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

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Colin H Kyle

Full Text Available 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

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

KAUST Repository

Sun, Jin

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

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

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Yan Liu

2011-09-01

Full Text Available 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.

The occurrence of digenean larvae in freshwater snails at Mbezi ...

African Journals Online (AJOL)

The occurrence of digenean larvae in freshwater snails at Mbezi-Temboni pond, Dar es Salaam. ESP Kigadye, G Nkwengulila. Abstract. The abundance of digenean larvae in snails at a pond in Mbezi-Temboni, Dar es Salaam, was investigated from July 1996 to June 1997. A total of 2,112 snails belonging to three species, ...

A temperature-dependent physiologically based model for the invasive apple snail Pomacea canaliculata

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Gilioli, Gianni; Pasquali, Sara; Martín, Pablo R.; Carlsson, Nils; Mariani, Luigi

2017-11-01

In order to set priorities in management of costly and ecosystem-damaging species, policymakers and managers need accurate predictions not only about where a specific invader may establish but also about its potential abundance at different geographical scales. This is because density or biomass per unit area of an invasive species is a key predictor of the magnitude of environmental and economic impact in the invaded habitat. Here, we present a physiologically based demographic model describing and explaining the population dynamics of a widespread freshwater invader, the golden apple snail Pomacea canaliculata, which is causing severe environmental and economic impacts in invaded wetlands and rice fields in Southeastern Asia and has also been introduced to North America and Europe . The model is based on bio-demographic functions for mortality, development and fecundity rates that are driven by water temperature for the aquatic stages (juveniles and adults) and by air temperature for the aerial egg masses. Our model has been validated against data on the current distribution in South America and Japan, and produced consistent and realistic patterns of reproduction, growth, maturation and mortality under different scenarios in accordance to what is known from real P. canaliculata populations in different regions and climates. The model further shows that P. canaliculata will use two different reproductive strategies (semelparity and iteroparity) within the potential area of establishment, a plasticity that may explain the high invasiveness of this species across a wide range of habitats with different climates. Our results also suggest that densities, and thus the magnitude of environmental and agricultural damage, will be largely different in locations with distinct climatic regimes within the potential area of establishment. We suggest that physiologically based demographic modelling of invasive species will become a valuable tool for invasive species managers.

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

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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.

Using ensemble forecasting to examine how climate change promotes worldwide invasion of the golden apple snail (Pomacea canaliculata).

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Lei, Juncheng; Chen, Lian; Li, Hong

2017-08-01

The golden apple snail, Pomacea canaliculata, is one of the world's 100 most notorious invasive alien species. Knowledge about the critical climate variables that limit the global distribution range of the snail, as well as predictions of future species distributions under climate change, is very helpful for management of snail. In this study, the climatically suitable habitats for this kind of snail under current climate conditions were modeled by biomod2 and projected to eight future climate scenarios (2 time periods [2050s, 2080s] × 2 Representative Concentration Pathways [RCPs; RCP2.6, RCP8.5] × 2 atmospheric General Circulation Models [GCMs; Canadian Centre for Climate Modelling and Analysis (CCCMA), Commonwealth Scientific and Industrial Research Organisation (CSIRO)]). The results suggest that the lowest temperature of coldest month is the critical climate variable to restrict the global distribution range of P. canaliculata. It is predicted that the climatically suitable habitats for P. canaliculata will increase by an average of 3.3% in 2050s and 3.8% in 2080s for the RCP2.6 scenario, while they increase by an average of 8.7% in 2050s and 10.3% in 2080s for the RCP8.5 scenario. In general, climate change in the future may promote the global invasion of the invasive species. Therefore, it is necessary to take proactive measures to monitor and preclude the invasion of this species.

Value-chain analysis of freshwater apple snail (Pila globosa used for on-farm feeds in the freshwater prawn farming sector in Bangladesh

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S.A.A. Nahid

2013-12-01

Full Text Available Growth of the freshwater prawn (Macrobrachium rosenbergii sector in Bangladesh since 1970s has been supported by natural availability of freshwater apple snail (Pila globosa, used for on-farm prawn feeds. The present study identified the current configuration of the value-chain benefits and constraints of freshwater apple snail in south-western Bangladesh in August 2011, based upon Rapid Market Appraisal (RMA approach. The site of snail collection was Chanda Beel in Gopalganj district, while trading, processing and final consumption was represented by Rayer Mahal Bazar in Khulna district. There were seven different nodes recognized throughout the value chain. Snail marketing was identified as a seasonal business and took place during June to November each year. Between 1995 and 2011 the price of whole snail, meat and shell has increased by 800%, 325% and 315%, respectively. The abundance of snail had been reduced and its demand has increased due to the expansion of the prawn farming industry. Prawn farmers preferred snail meat due to its’ low cost (US$ 0.21 kg-1 as a source of protein compared to commercial prawn feed (US$ 0.41 kg-1. Snail harvesting and processing were considered as additional livelihood options for the poor, where 60% of the labour involved in snail harvesting were women, and 95% the de-shelling workforce. Induced breeding in captivity and sustainable management in nature as well as development of commercial production of apple snails might reduce the pressure on ecosystems and positively contributed to the continued expansion of freshwater prawn farming in Bangladesh.

Scientific Opinion on the evaluation of the pest risk analysis on Pomacea insularum, the island apple snail, prepared by the Spanish Ministry of Environment and Rural and Marine Affairs

DEFF Research Database (Denmark)

Baker, R.; Candresse, T.; Dormannsné Simon, E.

2012-01-01

of the European Union have climatic conditions, that are very similar to those of the areas of native distribution of Pomacea spp. snails, and suitable host plants are available. The Panel agrees with the Spanish PRA on the following points with regard to the risk assessment area: (i) the potential consequences...

Complete mitochondrial genome of the giant ramshorn snail Marisa cornuarietis (Gastropoda: Ampullariidae).

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Wang, Mingling; Qiu, Jian-Wen

2016-05-01

We report the complete mitochondrial genome (mitogenome) of the giant ramshorn snail Marisa cornuarietis, a biocontrol agent of freshwater weeds and snail vectors of schistosomes. The mitogenome is 15,923 bp in length, encoding 13 protein-coding genes, 22 transfer RNAs and 2 ribosomal RNAs. The mitogenome is A+T biased (70.0%), with 28.9% A, 41.1% T, 16.7% G, and 13.3% C. A comparison with Pomacea canaliculata, the other member in the same family (Ampullariidae) with a sequenced mitogenome, shows that the two species have an identical gene order, but their intergenic regions vary substantially in sequence length. The mitogenome data can be used to understand the population genetics of M. cornuarietis, and resolve the phylogenetic relationship of various genera in Ampullariidae.

Modeling freshwater snail habitat suitability and areas of potential snail-borne disease transmission in Uganda

DEFF Research Database (Denmark)

Stensgaard, Anna-Sofie; Jørgensen, Aslak; Kabatereine, N B

2006-01-01

-borne disease transmission areas. Furthermore, knowledge of abiotic factors affecting intra-molluscan parasitic development can be used to make "masks" based on remotely sensed climatic data, and these can in turn be used to refine these predictions. We used data from a recent freshwater snail survey from......Geographic information system (GIS-based modeling of an intermediate host snail species environmental requirements using known occurrence records can provide estimates of its spatial distribution. When other data are lacking, this can be used as a rough spatial prediction of potential snail...... Uganda, environmental data and the genetic algorithm for rule-set prediction (GARP) to map the potential distribution of snail species known to act as intermediate hosts of several human and animal parasites. The results suggest that large areas of Uganda are suitable habitats for many of these snail...

Naididae (Annelida, Oligochaeta associated with Pomacea bridgesii (Reeve (Gastropoda, Ampullaridae Naididae (Annelida: Oligochaeta associados a Pomacea bridgesii (Reeve (Gastropoda, Ampullaridae

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Guilherme R. Gorni

2006-12-01

Full Text Available The family Amplullaridae belongs to this class Gastropoda and is made up of freshwater organisms with a wide geographical distribution in tropical regions. Oligochaeta worms can be found in association with snails of this family, inhabiting the umbilicus of their shells. Due to the lack of information on the ecology of these worms, this work focused on investigating which kind of Oligochaeta species associate with the mollusk Pomacea bridgesii (Reeve, 1856. Samples were collected during winter and spring 2003 and summer 2004. From a total of 209 snails collected, the presence of Oligochaeta worms was observed in only 58 of them (27.75%. In these infected snails, 89 Oligochaeta worms were found, all belonging to the family Naididae. The species Haemonais waldvogeli Bretscher, 1900, Dero (Dero nivea Aiyer, 1929 and Dero (Dero sawayai Marcus, 1943 were the most abundant (43.68%, 12.32% and 10.08%, respectively. Haemonais waldvogeli was found in all of the seasons studied, what demonstrates its affinity for this kind of substrate. The results indicate that several Naididae species find in the umbilicus of these snails's shells (which contains fine detritus a favorable habitat for establishing themselves.A família Ampullaridae, pertencente à classe Gastropoda, é caracterizada por organismos de água doce com ampla distribuição na região tropical. Vermes Oligochaeta associados a esses caracóis podem ser encontrados habitando o umbílico de suas conchas. Devido à carência de informação sobre a ecologia desses vermes, o presente trabalho centrou-se em um levantamento de espécies de Oligochaeta associadas ao molusco Pomacea bridgesii (Reeve, 1856. Em amostragens realizadas no inverno e na primavera de 2003 e no verão de 2004, foram observados 209 caracóis, sendo que somente em 58 deles foi detectada a presença de vermes Oligochaeta, correspondendo a uma incidência de 27,75%. Foram encontrados, no total, 89 oligoquetos, todos da fam

Biological control of golden apple snail, Pomacea canaliculata by Chinese soft-shelled turtle, Pelodiscus sinensis in the wild rice, Zizania latifolia field

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Shengzhang Dong

2012-04-01

Full Text Available The wild rice, Zizania latifolia Turcz, used to be one of the important aquatic vegetables cultivated in China. Recently, the golden apple snail - GAS (Pomacea canaliculata (Lamarck was found to be a major invasive pest attacking Z. latifolia. To control efficiently GAS, predation by the Chinese soft-shelled turtles (Pelodiscus sinensis on GAS was evaluated in laboratory and field trials. P. sinensis had a strong predatory capacity and selectivity for GAS both in laboratory and field conditions. All the sizes of P. sinensis prefer to capture smaller snails. The optimum number of P. sinensis released in Z. latifolia field was dependent on the density of over-wintered GAS, and varied between 30 and 50 turtles per 666.7 m². The number of GAS declined in the fields with turtles as compared to turtle-free field. A pattern of releasing P. sinensis in Z. latifolia fields was developed and widely adopted by farmers because of much more benefit besides biologically controlling GAS.

An overview of freshwater snails in Asia with main focus on Vietnam

DEFF Research Database (Denmark)

Madsen, Henry; Hung, N. M.

2014-01-01

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...

Fasciola hepatica: Infection Status of Freshwater Snails Collected from Gangwon-do (Province), Korea.

Science.gov (United States)

Lee, Jae-Hyung; Quan, Juan-Hua; Choi, In-Wook; Park, Gab-Man; Cha, Guang-Ho; Kim, Hyun-Ju; Yuk, Jae-Min; Lee, Young-Ha

2017-02-01

Fasciola hepatica is a trematode that causes zoonosis, mainly in cattle and sheep, and occasionally in humans. Few recent studies have determined the infection status of this fluke in Korea. In August 2015, we collected 402 samples of freshwater snails at Hoenggye-ri (upper stream) and Suha-ri (lower stream) of Song-cheon (stream) in Daegwalnyeong-myeon, Pyeongchang-gun in Gangwon-do (Province) near many large cattle or sheep farms. F. hepatica infection was determined using PCR on the nuclear ribosomal internal transcribed spacer 2 (ITS-2). Among the 402 samples, F. hepatica 1TS-2 marker was detected in 6 freshwater snails; thus, the overall prevalence in freshwater snails was 1.5%. The prevalence varied between collection areas, ranging from 0.0% at Hoenggye-ri to 2.9% at Suha-ri. However, F. gigantica ITS-2 was not detected in the 6 F. hepatica -positive samples by PCR. The nucleotide sequences of the 6 F. hepatica ITS-2 PCR-positive samples were 99.4% identical to the F. hepatica ITS-2 sequences in GenBank, whereas they were 98.4% similar to F. gigantica ITS-2 sequences. These results indicated that the prevalence of F. hepatica in snail intermediate hosts was 1.5% in Gangwon-do, Korea; however the prevalence varied between collection areas. These results may help us to understand F. hepatica infection status in natural environments.

Interactions between freshwater snails and tadpoles: competition and facilitation.

Science.gov (United States)

Brönmark, Christer; Rundle, Simon D; Erlandsson, Ann

1991-06-01

Freshwater snails and anuran tadpoles have been suggested to have their highest population densities in ponds of intermediate size where abiotic disturbance (e.g. desiccation) is low and large predators absent. Both snails and tadpoles feed on periphytic algae and, thus, there should be a large potential for competitive interactions to occur between these two distantly related taxa. In a field experiment we examined the relative strength of competition between two closely related snail species, Lymnaea stagnalis and L. peregra, and between L. stagnalis and tadpoles of the common frog, Rana temporaria. Snail growth and egg production and tadpole size at and time to metamorphosis were determined. Effects on the common food source, periphyton, were monitored with the aid of artificial substrates. Periphyton dry weight was dramatically reduced in the presence of snails and/or tadpoles. There were no competitive effects on growth or egg production of the two snail species when they were coexisting. Mortality of L. peregra was high (95%) after reproduction, but independent of treatment. Growth of L. stagnalis was reduced only at the highest tadpole densities, whereas egg production was reduced both by intraspecific competition and by competition with tadpoles. Differences in egg production were retained after tadpole metamorphosis. Tadpole larval period increased, weight of metamorphosing frogs decreased and growth rate was reduced as a function of increasing tadpole density. However, contrary to expectation, snails had a positive effect on tadpole larval period, weight and growth rate. Further, in experimental containers without snails there was a dense growth of the filamentous green alga Cladophora sp. We suggest that the facilitative effects of snails on tadpoles are due to an "indirect mutualistic" mechanism, involving competition between food sources of different quality (microalgae and Cladophora sp.) and tadpoles being competitively dominant over snails for the

Biological control and invading freshwater snails. A case study.

Science.gov (United States)

Pointier, J P; Augustin, D

1999-12-01

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

Development and Evaluation of Poly Herbal Molluscicidal Extracts for Control of Apple Snail (Pomacea maculata

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Guruswamy Prabhakaran

2017-03-01

Full Text Available Golden Apple Snail (GAS is the most destructive invasive rice pest in Southeast Asia. The cost of synthetic molluscicides, their toxicity to non-target organisms, and their persistence in the environment have propelled the research of plant-derived molluscicides. Most research efforts have focused on individual plant extracts for their molluscicidal potency against GAS and have not been proven to be entirely effective in rice field conditions. Selective combination of synergistically acting molluscicidal compounds from various plant extracts might be an effective alternative. In this direction, ethanolic extracts from six different plants (Neem, Tobacco, Nerium, Pongamia, Zinger, and Piper were evaluated against Pomacea maculata Perry. Of the various combinations studied, a binary extract (1:1 of nerium and tobacco (LC90 177.71 mg/L, 48 h, and two tri-herbal extract formulations (1:1:1 of (nerium + tobacco + piper and (nerium + tobacco + neem were found to be most effective, with LC90 values of 180.35 mg/L and 191.52 mg/L, respectively, in laboratory conditions. The synergistic effect of combined herbal extracts resulted in significant reduction in LC90 values of the individual extracts. The findings of this study demonstrate that the selective combinations of potent molluscicidal herbal extracts are effective for management of P. maculata under laboratory conditions.

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

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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.

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

International Nuclear Information System (INIS)

Kefford, Ben J.; Nugegoda, Dayanthi

2005-01-01

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

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

Science.gov (United States)

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.

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

Science.gov (United States)

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

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

Directory of Open Access Journals (Sweden)

Rita S. W. Yam

2016-02-01

Full Text Available 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.

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.

Science.gov (United States)

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.

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

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Chontananarth, Thapana; Wongsawad, Chalobol

2013-03-01

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

[Reproductive aspects of Pomacea flagellata (Mollusca: Ampullariidae) at Bacalar lagoon, Quintana Roo, México].

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Oliva-Rivera, José J; Ocaña, Frank A; Navarrete, Alberto de Jesús; Carrillo, Rosa M de Jesús; Vargas-Espósitos, Abel A

2016-12-01

The freshwater snail Pomacea flagellata is native from Southeastern Mexico. Studies about this species are scarce and none has treated their reproduction. This snail has been exploited at Bacalar lagoon for many years, leading to a significant decrease in their abundance and currently, a permanent ban was proposed by the government. This work aimed to assess the temporal variations of mating frequency and the abundance of egg clutches of P. flagellata at Bacalar lagoon, as well as their relation with snails density and environmental variables. Sampling was done during the three climatic seasons: Rainy (July, August and September/2012), North or Cold fronts (December/2012 and January and February/2013) and Dry (March, April and May/2013) in 12 sampling stations located along the Bacalar lagoon. On each station a transect of 100 m length was set parallel to the edge, and the number of fresh egg clutches (pink color) laid over vegetation, rocks or manmade structures, were counted. In the water, three 50 x 2 m transects were set and the number of snails were counted as well as the mating frequency. Density of snails varied significantly among seasons, decreasing from the rainy to the dry season. There were no significant differences of snail abundance among months, nested in climatic seasons (ANOVA, p>0.05). During the rainy season the mating frequency was significantly higher than in the Norths, meanwhile in the dry season no mating were registered (Kruskal-Wallis, p˂0.05). Eggs clutches appeared from July to March. Density of egg clutches presented no differences between the Rainy and the North seasons (2.72 and 2.93 clutches/m, respectively), nonetheless during the dry season abundance of egg masses was significantly lower (0.1 clutches/m) (H, p˂0.05). Mating frequency was related with snail abundance (rs= 0.26; p<0.05) and water temperature (rs= 0.34; p<0.05) and the abundance of egg masses is related with snail abundance (rs= 0.46; p<0.05). In general, we

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

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Christer Brönmark

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

Apple snails and their endosymbionts bioconcentrate heavy metals and uranium from contaminated drinking water.

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Vega, Israel A; Arribére, María A; Almonacid, Andrea V; Ribeiro Guevara, Sergio; Castro-Vazquez, Alfredo

2012-09-01

The differential ability of apple snail tissues, endosymbionts, and eggs to bioaccumulate several metals (Sb, As, Ba, Br, Zn, Cr, Fe, Hg, Se, and U) was investigated. Metal concentrations were determined by neutron activation analysis in several tissues, endosymbionts, and eggs from mature apple snails cultured in either drinking water or reconstituted water (prepared with American Society for Testing and Materials type I water). The highest bioconcentration factors (BCFs) in the midgut gland were found for Ba, Zn, Se, As, U, Br, and Hg (in decreasing order), while the highest in the kidney were for Ba, Br, and Hg. The foot showed the highest BCFs for Ba, Hg, Br, and Se (in decreasing order). Calcified tissues (uterus, shell) and eggs showed low BCFs, except for Ba. Both C corpuscles and gland tissue showed statistically higher BCFs than K corpuscles for Ba, Fe, U, Br, and Sb. The concentration of most of the studied elements was significantly lower in tissues and endosymbionts obtained from snails cultured in reconstituted water instead of drinking water. Snails cultured in reconstituted water and then exposed or not to Hg, As, and U (at the maximum contaminant level allowed by the US Environmental Protection Agency) also resulted in high levels accumulated in midgut gland, endosymbionts and kidney. Our findings suggest that the midgut gland (and the symbionts contained therein), the kidney, and the foot of Pomacea canaliculata may be useful bioindicators of Hg, As and U pollution in freshwater bodies and that the unrestricted use of ampullariid snails as human and animal food must be considered with caution.

Predation risk affects growth and reproduction of an invasive snail and its lethal effect depends on prey size

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Guo, Jing; Martín, Pablo R.; Zhang, Chunxia

2017-01-01

The behavior of invasive species under predation risk has been studied extensively, but their growth and reproductive responses have rarely been investigated. We conducted experiments with juveniles and adults of the invasive freshwater snail Pomacea canaliculata, and we observed changes in growth and reproduction in response to predation risk from a caged predator (Trachemys scripta elegans). P. canaliculata produced eggs earlier in the presence of predators and injured conspecifics compared with the control group (no risk), although the total number of egg masses laid by per female was exceeded by that of the controls after 15 days. Egg hatching success noticeably decreased under predation risk, and the incubation period was significantly prolonged; however, the oviposition height of the snails was not affected. A lethal effect of predation risk was detected in juvenile snails but not in adults. The growth of juvenile P. canaliculata was inhibited under predation risk, probably due to a reduction in food intake. Adult females exhibited a greater reduction in growth under predation risk than males, which likely resulted in part from the high reproductive investment of females in egg laying. These results indicate that P. canaliculata snails under predation risk face a trade-off between predator avoidance and growth and reproduction, where the lethal effect of predation risk is linked to the size of the prey. PMID:29136660

Predation risk affects growth and reproduction of an invasive snail and its lethal effect depends on prey size.

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Jing Guo

Full Text Available The behavior of invasive species under predation risk has been studied extensively, but their growth and reproductive responses have rarely been investigated. We conducted experiments with juveniles and adults of the invasive freshwater snail Pomacea canaliculata, and we observed changes in growth and reproduction in response to predation risk from a caged predator (Trachemys scripta elegans. P. canaliculata produced eggs earlier in the presence of predators and injured conspecifics compared with the control group (no risk, although the total number of egg masses laid by per female was exceeded by that of the controls after 15 days. Egg hatching success noticeably decreased under predation risk, and the incubation period was significantly prolonged; however, the oviposition height of the snails was not affected. A lethal effect of predation risk was detected in juvenile snails but not in adults. The growth of juvenile P. canaliculata was inhibited under predation risk, probably due to a reduction in food intake. Adult females exhibited a greater reduction in growth under predation risk than males, which likely resulted in part from the high reproductive investment of females in egg laying. These results indicate that P. canaliculata snails under predation risk face a trade-off between predator avoidance and growth and reproduction, where the lethal effect of predation risk is linked to the size of the prey.

The Use of Golden Snail (Pomacea sp. as Animal Feed in the Philippines

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Serra, AB.

1997-01-01

Full Text Available The golden snail is introduced to the Philippines in early 80's for culture as food source. This herbivorous snail, a voracious feeder of live and fresh plant materials become a serious rice pest. Its elimination in the ecosystems is impossible. To use them as animal feed is much better alternative for their control and more environmentally friendly than the use of chemicals. Thus, this mini review paper aimed to collate any existing information on the use of golden snail as animal feed. The different meal forms that can be extracted are golden snail meal (30 % calcium and 15 % crude protein, golden snail meat meal (62 % crude protein and 3336 kcal/kg and golden shell meal (35 % calcium. Feeding trials indicate that golden snail meal can be a part of swine and chicken layer diets up to 15 %. Golden snail meat meal can be a part of broiler chicken diet up to 12 %. Feeding fresh and ground golden snail to ducks can replace 50 % of their diet under total confinement system. Whereas, golden snail meat meal (75 % of the diet plus rice bran can be beneficially fed to tilapia. With the information collated, golden snail can be a promising animal feed in the Philippines.

Prime waterfront real estate: Apple snails choose wild taro for oviposition sites

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Colin H. KYLE, Alexis W. KROPF, Romi L. BURKS

2011-10-01

Full Text Available While difficult to prevent introductions, scientific research can help guide control efforts of exotic, invasive species. South American island apple snails Pomacea insularum have quickly spread across the United States Gulf Coast and few control measures exist to delay their spread. Usually occupying cryptic benthic habitats, female apple snails crawl out of the water to deposit large, bright pink egg clutches on emergent objects. To help identify the most likely place to find and remove clutches, we conducted four lab experiments to investigate what specific object qualities (i.e. material; shape and height; plant species; natural and artificial attracted P. insularum females to lay clutches. In our fourth experiment, we specifically examined the relationship between female size and reproductive output. To further understand reproductive output, we quantified experimental clutch chara- cteristics (height above water, dimensions, mass, approximate volume, number of eggs, hatching efficiency. Pomacea insularum females laid more clutches on plant material, chose round over flat surfaces and failed to differentiate between tall and short structures. In comparison to a common native plant in the eastern US, Pontederia cordata, snails clearly preferred to lay clutches on a widely distributed exotic, invasive plant (wild taro, Colocasia esculenta. Unexpectedly, smaller snails showed higher overall total fecundity as well as more eggs per clutch than larger snails. Therefore, hand removal efforts of large females may not be enough to slow down clutch production. Collectively, our results indicate that conservationists and managers should search emergent plants for P. insularum clutches carefully to guard against established populations [Current Zoology 57 (5: 630–641, 2011].

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

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Larcher, Marie; Crane, Adam L

2015-12-01

Chemically-mediated orientation is essential for many animals that must locate sites containing resources such as mates or food. One way to find these areas is by using publically-available information from other individuals. We tested a freshwater snail, Physa gyrina, for chemoreception of conspecific cues and predicted they could discriminate between cues based on information regarding hunger levels. We placed 'tracker' snails into a 2-arm arena where they could either follow or avoid an area previously used by a 'marker' snail. The hunger levels of both trackers and markers was manipulated, being either starved or fed. Starved and fed trackers did not differ in their following response when markers were hungry, but starved trackers were significantly more likely to follow fed markers, compared to fed trackers that tended to avoid areas used by fed markers. This outcome suggests that P. gyrina uses conspecific chemical cues to find food and potentially in some situations to avoid intra-specific food competition. Copyright © 2015 Elsevier B.V. All rights reserved.

Tributyltin bioaccumulation and toxic effects in freshwater gastropods Pomacea canaliculata after a chronic exposure: field and laboratory studies.

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Martínez, María L; Piol, María N; Sbarbati Nudelman, Norma; Verrengia Guerrero, Noemí R

2017-07-01

Freshwater samples and gastropod mollusks (Pomacea canaliculata) were collected at 5 sampling stations located along the lower Río de la Plata basin, Argentina, to assess the extent of tributyltin (TBT) contamination. Determined data revealed the presence of TBT and some of its breakdown products (dibutyltin: DBT, and monobutyltin: MBT) in all freshwater samples and also in soft tissues of P. canaliculata gastropods. Chronic bioassays (6 months) were performed using female gastropods that had been reared under laboratory conditions and exposed to a similar TBT concentration than the value determined in freshwater samples (1 µg L -1 ). The aims of this study were to evaluate the extent of TBT accumulation, the tissue distribution, and the effects on selected biomarkers (activity of superoxide dismutasa: SOD, activity of catalase: CAT, levels of total glutathione: t-GSH, lipid peroxidation, and activity of acetylcholinesterase: AChE). Gonads presented the highest accumulation, followed by the cephalopedal region, albumin gland, and finally hepatopancreas. Both metabolites, DBT and MBT, were also found. All exposed female animals presented development of a penis reflecting the potential of TBT as an endocrine disrupting chemical for this gastropod species. Results on the selected biomarkers confirmed additional adverse effects induced by TBT. An increase in CAT activity and changes in t-GSH levels are indicative of alterations on the cellular redox status. The inhibition of AChE could reflect signs of neurotoxicity. Altogether, these results reveal a negative impact on the health of this gastropod population.

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

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Kefford, Ben J; Nugegoda, Dayanthi

2005-04-01

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

Assessment the Molluscicidal Properties of Azadirachtin Against Golden Apple Snail, Pomacea Canaliculata

International Nuclear Information System (INIS)

Rosdiyani Massaguni; Siti Noor Hajjar Mohd Latip

2015-01-01

Concern with the negative impact of synthetic pesticide on environment and human health have led this study in order to evaluate the molluscicidal efficacies of azadirachtin in neem seed crude extract on golden apple snail. Azadirachtin was extracted by maceration technique using four different solvents and the quantity of azadirachtin in extracts was compared to select the best solvent. Then, bioassays were performed on adult of golden apple snail to compare the molluscicidal activity of azadirachtin. A comparison of the extractive yields of different solvents indicated that the polarity of the solvents tested not significantly influence in enhanced the azadirachtin yields. The result on mortality rate of golden apple snail subjected to various concentration and solvent extracts indicated that neem seed crude extracts significantly killed the golden apple snail. The LC 50 values of the methanol extract (21.008 mg/ ml) were the lowest, indicating the highest potency, followed in order by ethanol extract (43.726 mg/ ml), acetone extract (48.110 mg/ ml) and water extract (53.654 mg/ ml). The mortality rate was correlated positively with the extract concentrations as the mortality of snail increased with the increase of extract concentration. Therefore, this study indicated that neem seed crude extracts possessed molluscicidal effect for controlling the golden apple snail. (author)

The maintenance of hybrids by parasitism in a freshwater snail.

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Guttel, Yonathan; Ben-Ami, Frida

2014-11-01

Hybrids have often been labelled evolutionary dead-ends due to their lower fertility and viability. However, there is growing awareness that hybridisation between different species may play a constructive role in animal evolution as a means to create variability. Thus, hybridisation and introgression may contribute to adaptive evolution, for example with regards to natural antagonists (parasites, predators, competitors) and adaptation to local environmental conditions. Here we investigated whether parasite intensity contributes to the continuous recreation of hybrids in 74 natural populations of Melanopsis, a complex of freshwater snails with three species. We also examined, under laboratory conditions, whether hybrids and their parental taxa differ in their tolerance of low and high temperatures and salinity levels. Infections were consistently less prevalent in males than in females, and lower in snails from deeper habitats. Infection prevalence in hybrids was significantly lower than in the parental taxa. Low hybrid infection rates could not be explained by sediment type, snail density or geographic distribution of the sampling sites. Interestingly, infected hybrid snails did not show signs of parasite-induced gigantism, whereas all parental taxa did. We found that hybrids mostly coped with extreme temperatures and salinity levels as well as their parental taxa did. Taken together, our results suggest that Melanopsis hybrids perform better in the presence of parasites and environmental stress. This may explain the widespread and long-term occurrence of Melanopsis hybrids as evidenced by paleontological and biogeographic data. Hybridisation may be an adaptive host strategy, reducing infection rates and resisting gigantism. Copyright © 2014 Australian Society for Parasitology Inc. Published by Elsevier Ltd. All rights reserved.

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

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Pointier, J P

2001-01-01

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

Endosymbiotic and host proteases in the digestive tract of the invasive snail Pomacea canaliculata: diversity, origin and characterization.

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Martín S Godoy

Full Text Available 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.

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

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Franca Maltez, Heloisa [Department of Physical and Analytical Chemistry, Faculty of Chemistry, University of Oviedo, Julian Claveria 8, 33006 Oviedo (Spain); Villanueva Tagle, Margarita [Faculty of Chemistry, University of La Habana (Cuba); Rosario Fernandez de la Campa, Maria del [Department of Physical and Analytical Chemistry, Faculty of Chemistry, University of Oviedo, Julian Claveria 8, 33006 Oviedo (Spain); Sanz-Medel, Alfredo, E-mail: asm@uniovi.es [Department of Physical and Analytical Chemistry, Faculty of Chemistry, University of Oviedo, Julian Claveria 8, 33006 Oviedo (Spain)

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.

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

Science.gov (United States)

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.

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

International Nuclear Information System (INIS)

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

2009-01-01

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.

Insights into embryo defenses of the invasive apple snail Pomacea canaliculata: egg mass ingestion affects rat intestine morphology and growth.

Science.gov (United States)

Dreon, Marcos S; Fernández, Patricia E; Gimeno, Eduardo J; Heras, Horacio

2014-06-01

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. 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. 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 the toxic effect of plant antipredator strategies. This defense

Insights into embryo defenses of the invasive apple snail Pomacea canaliculata: egg mass ingestion affects rat intestine morphology and growth.

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Marcos S Dreon

2014-06-01

Full Text Available 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.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.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 the toxic effect of plant antipredator strategies

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

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Emmanuel Noumi

2008-03-01

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

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

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Jean-Pierre Pointier

2001-09-01

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

Echinostoma revolutum: freshwater snails as the second intermediate hosts in Chiang Mai, Thailand.

Science.gov (United States)

Chantima, Kittichai; Chai, Jong-Yil; Wongsawad, Chalobol

2013-04-01

The occurrence of 37-collar spined echinostome metacercariae in freshwater snails was investigated in 6 districts of Chiang Mai Province, Thailand, from October 2011 to April 2012. A total of 2,914 snails that belong to 12 species were examined, and 7 snail species (Clea helena, Eyriesia eyriesi, Bithynia funiculata, Bithynia siamensis siamensis, Filopaludina doliaris, Filopaludina sumatrensis polygramma, and Filopaludina martensi martensi) were found infected with echinostome metacercariae. The prevalence of metacercariae was the highest in Filopaludina spp. (38.5-58.7%) followed by B. funiculata (44.0%), E. eyriesi (12.5%), B. siamensis siamensis (8.2%), and C. helena (5.1%). Metacercariae were experimentally fed to hamsters and domestic chicks, and adult flukes were recovered from both hosts at days 15 and 20 post-infection. The adult flukes were identified based on morphological features, morphometrics, host-parasite relationships, and geographical distribution. They were compatible to Echinostoma revolutum or Echinostoma jurini, with only minor differences. As the adults were recovered from both hamsters and chicks, our specimens were more compatible to E. revolutum rather than E. jurini (reported only from mammals). This is the first report for metacercariae of E. revolutum in the snail host, C. helena, and also confirmed that Filopaludina spp., E. eryresi, and Bithynia spp. act as the second intermediate hosts of E. revolutum under natural conditions, which are indigenously distributed in Chiang Mai province.

Toxicity of Metals to a Freshwater Snail, Melanoides tuberculata

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M. Shuhaimi-Othman

2012-01-01

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

Types of trematodes infecting freshwater snails found in irrigation canals in the East Nile locality, Khartoum, Sudan

DEFF Research Database (Denmark)

Mohammed, Nidal A. I.; Madsen, Henry; Ahmed, Abdel Aziz A. R. M.

2016-01-01

Background: The planorbid freshwater snails of the two genera, Biomphalaria and Bulinus -have been vigorously studied due to the role they play as intermediate hosts of schistosomiasis. In Sudan specifically, most studies have focused on the chemical and ecological control of the two genera, but ...

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

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Zhuo MingMing

2011-10-01

Full Text Available Abstract 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.

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

CSIR Research Space (South Africa)

Musee, N

2010-01-01

Full Text Available -alumina, modified TiO2 (M-TiO2), and commercial TiO2 (C-TiO2) ENPs on the survival, behaviour, and early life stages of the freshwater snail Physa acuta (Draparnaud). The toxicity evaluation was carried out after spiking commercial sand with ENPs concentrations of 0...

Current Situation of Edible Snails in Indonesia

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Schneider, K.

1999-01-01

Full Text Available From March 7, 1995 to April 16, 1995 du ring the rainy season the utilisation of edible snails was investigated in Indonesia. To assess the current situation, the focus was put to answer the following questions : - Is it feasible under the present circumstances to domesticate these snails with the aim to conserve the natural resources ? - Could any individual or private initiative be enhanced or utilized ? - Would local disadvantaged groups (traditional animal farmers, women oryouths be benefitted through domestication of these snails ? - Is there any existing private organisation or NGO, which already gathers and trades the snails or would be interested to do this in the future ? Snails gatherers, -dealers and -farmers were visited and interviewed on the following topics using standardised questionnaires : Spreading and ecology ways of marketing, consumption habits, breeding and rearing. Diotopes were also visited and investigated. Results Spreading and ecology : Achatina fulica, Pomacea canaliculata, Pila ampullacea and Bellamia javanica are eaten. The snails can be found ail overJava. Ways of marketing : The snails gathered in the biotope are either marketed directly or through various marketing paths. A. fulica is exported in large quantifies. The population is therefore endangered. Consumption habits : Snails are not eaten regularly. Snail meat is known to be healthy. The consumption depends on the consumer's ethnie background. Breeding and rearing experience : with simple breeding systems for A. fulica and P. canaliculata are seldom found. The breeding of P. canaliculata is forbidden in Indonesia. There is no interest in breeding P. ampullacea or B. javanica. The breeding of A. fulica can ben-efit disadvantaged groups financially and help to conserving the natural snail population.

Comparison of four species of snails as potential decoys to intercept schistosome miracidia.

Science.gov (United States)

Laracuente, A; Brown, R A; Jobin, W

1979-01-01

Preliminary studies have shown that various species of aquatic snails may be used as decoys or "sponges" to intercept schistosome miracidia, thereby preventing the miracidia from reaching the snails which normally serve as their intermediate host. In this study, four species of snails were evaluated as candidate decoys for field trials: Marisa cornuarietis, Pomacea australis, Helisoma caribaeum, and Tarebia granifera. In the laboratory all four species caused considerable reductions in the proportion of Biomphalaria glabrata infected by miracidia of Schistosoma mansoni. The most effective decoys were M. cornuarietis and H. caribaeum, both of which caused experimental infection levels of 90% to decrease to 25% when five decoy snails were present for each target snail. When ten decoy snails were present for each target snail, the proportion infected decreased to 1%. M. cornuarietis was chosen as the candidate for field trials because it was found more frequently in Puerto Rico than was H. caribaeum. Initial field trials in two ponds showed that M. cornuarietis blocked infections at a ratio of 6 decoys to 1 target snail, confirming the laboratory results. Further studies in flowing water are needed before the technique can be generally evaluated in an endemic area.

DAYA MAKAN, DIAPAUSE DAN MOBILITAS KEONG MAS (POMACEA CANALICULATA PADA BERBAGAI KEDALAMAN AIR

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Jacqualine Arriani Bunga

2017-04-01

Full Text Available Feeding rate, aestivation and mobility of golden snails (Pomacea canaliculata at different depths of water. The research was studied in Malaka District, East Nusa Tenggara Province, during the dry and the rainy season (October 2014 - March 2015. Studies on capacity of damage to the Ciherang rice seedlings were carried out for three weeks. The size of snails used in this experiment was 11-20; 21-30; and 31-40 mm. The numbers of seedlings that were planted were 3, 6, 9, 12, 15, 18 and 21 seeds. The treatments were repeated 5 times. The numbers of seeds which are damaged by the snails then were tabulated and analyzed. Snails with the size of 11-20 mm damaged the seeds in 31.67%, followed by snails with the size of 21-30 mm and 31- 40 mm with potency of damaging were 64.76% and 97.38%, respectively. The size of snails affects the level of damage to rice seedlings when transplanting. Study about aestivation was conducted in five villages, namely Kamanasa, Wehali, Umakatahan, Harekakae and Kletek when the rice fields were fallow. The observation point was observed at the corner of the dike and along the dike, evaluated every 10 meters away. The results showed snails aestivate when the fields were dry. Studies on snail’s mobility conducted on the experiment arena on the mud in buckets, which planted with 20 paddy seedlings. The treatment depth of puddles in the experiment were without puddles, half, the same height and twice the height of snails shell. The treatments were repeated 10 times. Measurement of snail’s mobility was performed routinely every 2 hours, observed from the beginning when the snails were placed for 24 hours in advance. The results showed that the depth of the water significantly affected the mobility of snails. Without puddles, the mobility of snails was severely hampered in the mud. The mobility of the juvenile was significantly higher than the imago. The implication of this study was benefit to that the regulating the level

Chemical speciation and bioavailability of transuranics for a freshwater snail (Lymnaea stagnalis L.)

International Nuclear Information System (INIS)

Thiels, G.M.; Murray, C.N.; Rade, J.

1981-01-01

It is now becoming clear that the determination of the physico-chemical forms of transuranic elements is an important step in assessing their behaviour at very low environmental levels. Data from both simulated environmental systems as well as in-situ investigations have shown the necessity of understanding the source term of contamination, which probably plays a major role in the long-term distribution of these elements. In the present paper an experimental procedure is outlined, which allows a more extensive investigation into some aspects of the biogeochemical behaviour of two transuranics: 237 Pu and 241 Am. Two chemical methods were applied to a study of the freshwater snail Lymnaea stagnalis L.. Data were obtained on the uptake and retention patterns of different oxidation states of 237 Pu and 241 Am at the organ and cellular levels of the pond snail. An attempt was made to relate the environmental chemistry of both radionuclides to the fixation in L. stagnalis. (author)

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

Science.gov (United States)

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

2013-01-01

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

Alterations in carbohydrates and the protein metabolism of the harmful freshwater vector snail Lymnaea acuminata induced by the Euphorbia tirucalli latex extract.

Science.gov (United States)

Tiwari, Sudhanshu; Singh, A

2005-11-01

To know the short- as well as long-term effect of aqueous latex extracts of Euphorbia tirucalli on carbohydrate and protein metabolism, the snail Lymnaea acuminata was exposed to sublethal doses of 0.37 and 0.55 mg/L for a 24-h and 0.20 and 0.31 mg/L for a 96-h exposure period. Significant (P<0.05) alterations in the glycogen, pyruvate, lactate, total protein, and free amino acid level, as well as in the activity of enzyme lactic dehydrogenase, succinic dehydrogenase, cytochrome oxidase, protease, aspartate aminotransaminase, and alanine aminotransaminase were observed in the nervous, hepatopancreatic, and ovotestis tissues of the freshwater vector snail L. acuminata exposed to sublethal doses of E. tirucalli latex extract. The alterations in all biochemical parameters were significantly (P<0.05) time and dose dependent. After the 7th day of the withdrawal of treatment, there was significant (P<0.05) recovery in glycogen, pyruvate, lactate, total protein, and the free amino acid level and in the activity of the lactic dehydrogenase, succinic dehydrogenase, cytochrome oxidase, protease, aspartate aminotransaminase and alanine aminotransaminase enzymes in all three of the studied tissues of the snail, which supports the view that the plant product is safe for use as a molluscicide for the control of harmful freshwater vector snails in the aquatic environment.

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.

Science.gov (United States)

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

Bioaccumulation of sup(95m)Tc in fish and snails

Energy Technology Data Exchange (ETDEWEB)

Blaylock, B.G.; Frank, M.L.; DeAngelis, D.L. (Oak Ridge National Lab., TN (USA))

1982-03-01

Concentration factors for technetium recommended in radiological assessment models for freshwater biota are default values based on the behavior of iodine in the environment. A small experimental freshwater pond was spiked with sup(95m)Tc to obtain data for calculating concentration factors for fish and snails. A model using the pond data was developed to calculate steady-state body burdens for freshwater biota. The concentration factors based on the calculated body burden for carp (Caprinus carpio), mosquitofish (Gambusia affinis), and snails (Helisoma sp.) were 11,75 and 121, respectively. The concentration factor for carp was less than the recommended value of 15 listed in the USNRC Regulatory Guide 1.109 for calculating radiation dose to man; however, the concentration factors for mosquitofish and snails exceeded the recommended values by 5 and 25 times, respectively.

Comparative proteomics and codon substitution analysis reveal mechanisms of differential resistance to hypoxia in congeneric snails

KAUST Repository

Mu, Huawei; Sun, Jin; Cheung, Siu Gin; Fang, Ling; Zhou, Haiyun; Luan, Tiangang; Zhang, Huoming; Wong, Chris K.C.; Qiu, Jian-Wen

2017-01-01

Although high-throughput proteomics has been widely applied to study mechanisms of environmental adaptation, the conclusions from studies that are based on one species can be confounded by phylogeny. We compare the freshwater snail Pomacea canaliculata (a notorious invasive species) and its congener Pomacea diffusa (a non-invasive species) to understand the molecular mechanisms of their differential resistance to hypoxia. A 72-h acute exposure experiment showed that P. canaliculata is more tolerant to hypoxia than P. diffusa. The two species were then exposed to three levels of dissolved oxygen (6.7, 2.0 and 1.0mgL−1) for 8h, and their gill proteins were analyzed using iTRAQ-coupled LC-MS/MS. The two species showed striking differences in protein expression profiles, with the more hypoxia tolerant P. canaliculata having more up-regulated proteins in signal transduction and down-regulated proteins in glycolysis and the tricarboxylic acid cycle. Evolutionary analysis revealed five orthologous genes encoding differentially expressed proteins having clear signal of positive selection, indicating selection has acted on some of the hypoxia responsive genes. Our case study has highlighted the potential of integrated proteomics and comparative evolutionary analysis for understanding the genetic basis of adaptation to global environmental change in non-model species. SignificanceRapid globalization in recent decades has greatly facilitated species introduction around the world. Successfully established introduced species, so-called invasive species, have threatened the invaded ecosystems. There has been substantial interest in studying how invasive species respond to extreme environmental conditions because the results can help not only predict their range of expansion and manage their impact, but also may reveal the adaptive mechanisms underlying their invasiveness. Our study has adopted a comparative approach to study the differential physiological and proteomic

Comparative proteomics and codon substitution analysis reveal mechanisms of differential resistance to hypoxia in congeneric snails

KAUST Repository

Mu, Huawei

2017-11-06

Although high-throughput proteomics has been widely applied to study mechanisms of environmental adaptation, the conclusions from studies that are based on one species can be confounded by phylogeny. We compare the freshwater snail Pomacea canaliculata (a notorious invasive species) and its congener Pomacea diffusa (a non-invasive species) to understand the molecular mechanisms of their differential resistance to hypoxia. A 72-h acute exposure experiment showed that P. canaliculata is more tolerant to hypoxia than P. diffusa. The two species were then exposed to three levels of dissolved oxygen (6.7, 2.0 and 1.0mgL−1) for 8h, and their gill proteins were analyzed using iTRAQ-coupled LC-MS/MS. The two species showed striking differences in protein expression profiles, with the more hypoxia tolerant P. canaliculata having more up-regulated proteins in signal transduction and down-regulated proteins in glycolysis and the tricarboxylic acid cycle. Evolutionary analysis revealed five orthologous genes encoding differentially expressed proteins having clear signal of positive selection, indicating selection has acted on some of the hypoxia responsive genes. Our case study has highlighted the potential of integrated proteomics and comparative evolutionary analysis for understanding the genetic basis of adaptation to global environmental change in non-model species. SignificanceRapid globalization in recent decades has greatly facilitated species introduction around the world. Successfully established introduced species, so-called invasive species, have threatened the invaded ecosystems. There has been substantial interest in studying how invasive species respond to extreme environmental conditions because the results can help not only predict their range of expansion and manage their impact, but also may reveal the adaptive mechanisms underlying their invasiveness. Our study has adopted a comparative approach to study the differential physiological and proteomic

Production of apple snail for space diet

Science.gov (United States)

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

Evolutionary implications of a high selfing rate in the freshwater snail Lymnaea truncatula.

Science.gov (United States)

Trouvé, S; Degen, L; Renaud, F; Goudet, J

2003-10-01

Self-compatible hermaphroditic organisms that mix self-fertilization and outcrossing are of great interest for investigating the evolution of mating systems. We investigate the evolution of selfing in Lymnaea truncatula, a self-compatible hermaphroditic freshwater snail. We first analyze the consequences of selfing in terms of genetic variability within and among populations and then investigate how these consequences along with the species ecology (harshness of the habitat and parasitism) might govern the evolution of selfing. Snails from 13 localities (classified as temporary or permanent depending on their water availability) were sampled in western Switzerland and genotyped for seven microsatellite loci. F(IS) (estimated on adults) and progeny array analyses (on hatchlings) provided similar selfing rate estimates of 80%. Populations presented a low polymorphism and were highly differentiated (F(ST) = 0.58). Although the reproductive assurance hypothesis would predict higher selfing rate in temporary populations, no difference in selfing level was observed between temporary and permanent populations. However, allelic richness and gene diversity declined in temporary habitats, presumably reflecting drift. Infection levels varied but were not simply related to either estimated population selfing rate or to differences in heterozygosity. These findings and the similar selfing rates estimated for hatchlings and adults suggest that within-population inbreeding depression is low in L. truncatula.

Bioaccumulation of /sup 95m/Tc in fish and snails

Energy Technology Data Exchange (ETDEWEB)

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

1982-03-01

Concentration factors for technetium recommended in radiological assessment models for freshwater biota are default values based on the behavior of iodine in the environment. In this study a small experimental freshwater pond was spiked with /sup 95/mTc to obtain data for calculating concentration factors for fish and snails. A model using the pond data was developed to calculate steady-state body burdens for freshwater biota. The concentration factors based on the calculated body burden for carp (Caprinus carpio), mosquitofish (Gambusia affinis), and snails (Helisoma sp.) were 11, 75 and 121, respectively. The concentration factor for carp was less than the recommended value of 15 listed in the USNRC Regulatory Guide 1.109 for calculating radiation dose to man; however, the concentration factors for mosquitofish and snails exceeded the recommended values by 5 and 24 times, respectively.

Whole genome analysis of a schistosomiasis-transmitting freshwater snail

NARCIS (Netherlands)

Adema, Coen M; Hillier, LaDeana W; Jones, Catherine S; Loker, Eric S; Knight, Matty; Minx, Patrick; Oliveira, Guilherme; Raghavan, Nithya; Shedlock, Andrew; do Amaral, Laurence Rodrigues; Arican-Goktas, Halime D; Assis, Juliana G; Baba, Elio Hideo; Baron, Olga L; Bayne, Christopher J; Bickham-Wright, Utibe; Biggar, Kyle K; Blouin, Michael; Bonning, Bryony C; Botka, Chris; Bridger, Joanna M; Buckley, Katherine M; Buddenborg, Sarah K; Lima Caldeira, Roberta; Carleton, Julia; Carvalho, Omar S; Castillo, Maria G; Chalmers, Iain W; Christensens, Mikkel; Clifton, Sandra; Cosseau, Celine; Coustau, Christine; Cripps, Richard M; Cuesta-Astroz, Yesid; Cummins, Scott F; di Stephano, Leon; Dinguirard, Nathalie; Duval, David; Emrich, Scott; Feschotte, Cédric; Feyereisen, Rene; FitzGerald, Peter; Fronick, Catrina; Fulton, Lucinda; Galinier, Richard; Gava, Sandra G; Geusz, Michael; Geyer, Kathrin K; Giraldo-Calderón, Gloria I; de Souza Gomes, Matheus; Gordy, Michelle A; Gourbal, Benjamin; Grunau, Christoph; Hanington, Patrick C; Hoffmann, Karl F; Hughes, Daniel; Humphries, Judith; Jackson, Daniel J; Jannotti-Passos, Liana K; de Jesus Jeremias, Wander; Jobling, Susan; Kamel, Bishoy; Kapusta, Aurélie; Kaur, Satwant; Koene, Joris M; Kohn, Andrea B; Lawson, Dan; Lawton, Scott P; Liang, D.C.; Limpanont, Yanin; Liu, Sijun; Lockyer, Anne E; Lovato, TyAnna L; Ludolf, Fernanda; Magrini, Vince; McManus, Donald P; Medina, Monica; Misra, Milind; Mitta, Guillaume; Mkoji, Gerald M; Montague, Michael J; Montelongo, Cesar; Moroz, Leonid L; Munoz-Torres, Monica C; Niazi, Umar; Noble, Leslie R; Oliveira, Francislon S; Pais, Fabiano S; Papenfuss, Anthony T; Peace, Rob; Pena, Janeth J; Pila, Emmanuel A; Quelais, Titouan; Raney, Brian J; Rast, Jonathan P; Rollinson, David; Rosse, Izinara C; Rotgans, Bronwyn; Routledge, Edwin J; Ryan, Kathryn M; Scholte, Larissa L S; Storey, Kenneth B; Swain, Martin; Tennessen, Jacob A; Tomlinson, Chad; Trujillo, Damian L; Volpi, Emanuela V; Walker, Anthony J; Wang, Tianfang; Wannaporn, Ittiprasert; Warren, Wesley C; Wu, Xiao-Jun; Yoshino, Timothy P; Yusuf, Mohammed; Zhang, Si-Ming; Zhao, Min; Wilson, Richard K

2017-01-01

Biomphalaria snails are instrumental in transmission of the human blood fluke Schistosoma mansoni. With the World Health Organization's goal to eliminate schistosomiasis as a global health problem by 2025, there is now renewed emphasis on snail control. Here, we characterize the genome of

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

Science.gov (United States)

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

2015-12-15

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

Whole genome analysis of a schistosomiasis-transmitting freshwater snail

DEFF Research Database (Denmark)

Adema, Coen M; Hillier, Ladeana W; Jones, Catherine S

2017-01-01

Biomphalaria snails are instrumental in transmission of the human blood fluke Schistosoma mansoni. With the World Health Organization's goal to eliminate schistosomiasis as a global health problem by 2025, there is now renewed emphasis on snail control. Here, we characterize the genome of Biompha...

Utilization Of Golden Snail As Alternative Liquid Organic Fertilizer LOF On Paddy Farmers In Dairi Indonesia

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Ameilia Zuliyanti Siregar

2017-11-01

Full Text Available Golden snail Pomaceae canaliculata is a pest of rice plants and used as a food source to be processed into satay seasoning spices biscuits pastry candy crackers animal feed and fertilizer. In Lae Parira village the golden snail is very diverse. Because of this reason the preliminary study and utilization of golden snail used for of liquid organic fertilizer called LOF or and microorganisms local MOL. The golden snail is obtained from a livestock that is still alive and then washed boiled and removed from its shell. The golden snail meat is cut into small pieces separated from the intestine and other visceral organs. Flesh of golden snail give coconut water dilute brown sugar EM4 and fermentation until 10-14 days. The use of mashed LOF can be sprayed on the surface of the soil or all parts of the plant. For fertilization in rice plants the recommended dose of 250 ml15 liters of water is sprayed on the rice age 10 days after planting and repeated again at interval distance of 15 days. Fertilization on the plant recommended 200ml 15 liters of water sprayed on leaves and soil 7 days after planting and repeated every 7 days. The golden snail is potensial used for fertilizer in paddy plantation environmentally.

The effects of wetland habitat structure on Florida apple snail density

Science.gov (United States)

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

2006-01-01

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

Diet quality affects chemical tolerance in the freshwater snail Lymnaea stagnalis.

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Fidder, Bridgette N; Reátegui-Zirena, Evelyn G; Salice, Christopher J

2018-04-01

Organisms generally select high-quality diets to obtain maximal energy while devoting the least amount of time and energy. Diets, however, can vary in natural systems. In ecotoxicological testing, the effect of diet type on organismal responses to toxicants has not been explored despite the potential for dietary effects to influence toxicological endpoints. We first evaluated diet quality using growth rate and sensitivity to the fungicide pyraclostrobin of Lymnaea stagnalis fed lettuce (common laboratory diet), turtle pellets (high nutrient composition), and a combination diet of both food items. We also measured the macronutrient content of snails raised on the multiple diets to determine how diet may have impacted energy allocation patterns. Finally, we evaluated whether snails discernibly preferred a particular diet. Snails fed high-nutrient and combination diets grew larger overall than snails fed a lettuce-only diet. Snails fed the high-nutrient and combination diets, both juvenile and adult, were significantly more tolerant to pyraclostrobin than snails fed lettuce. When measured for macronutrient content, snails raised on high-nutrient and combination diets had significantly higher carbohydrate content than snails fed lettuce. Despite the strong effects of diet type, snails did not exhibit a clear diet choice in preference trials. Dietary composition clearly influences growth rate, sensitivity, and macronutrient content of Lymnaea stagnalis. These results suggest that the nutritional environment has potentially strong impacts on toxicant sensitivity. Environ Toxicol Chem 2018;37:1158-1167. © 2017 SETAC. © 2017 SETAC.

Copper desorption in flooded agricultural soils and toxicity to the Florida apple snail (Pomacea paludosa): Implications in Everglades restoration

International Nuclear Information System (INIS)

Hoang, Tham C.; Rogevich, Emily C.; Rand, Gary M.; Gardinali, Piero R.; Frakes, Robert A.; Bargar, Timothy A.

2008-01-01

Copper (Cu) desorption and toxicity to the Florida apple snail were investigated from soils obtained from agricultural sites acquired under the Comprehensive Everglades Restoration Plan. Copper concentrations in 11 flooded soils ranged from 5 to 234 mg/kg on day 0 and from 6.2 to 204 mg/kg on day 28 (steady-state). The steady-state Cu concentration in overlying water ranged from 9.1 to 308.2 μg/L. In a 28-d growth study, high mortality in snails occurred within 9 to 16 d in two of three soil treatments tested. Growth of apple snails over 28 d was affected by Cu in these two treatments. Tissue Cu concentrations by day 14 were 12-23-fold higher in snails exposed to the three soil treatments compared to controls. The endangered Florida snail kite and its main food source, the Florida apple snail, may be at risk from Cu exposure in these managed agricultural soil-water ecosystems. - Copper desorbs from agricultural soils and is toxic to the Florida apple snail

[Conversion methods of freshwater snail tissue dry mass and ash free dry mass].

Science.gov (United States)

Zhao, Wei-Hua; Wang, Hai-Jun; Wang, Hong-Zhu; Liu, Xue-Qin

2009-06-01

Mollusk biomass is usually expressed as wet mass with shell, but this expression fails to represent real biomass due to the high calcium carbonate content in shells. Tissue dry mass and ash free dry mass are relatively close to real biomass. However, the determination process of these two parameters is very complicated, and thus, it is necessary to establish simple and practical conversion methods for these two parameters. A total of six taxa of freshwater snails (Bellamya sp., Alocinma longicornis, Parafossarulus striatulus, Parafossarulus eximius, Semisulcospira cancellata, and Radix sp.) common in the Yangtze Basin were selected to explore the relations of their five shell dimension parameters, dry and wet mass with shells with their tissue dry mass and ash free dry mass. The regressions of the tissue dry mass and ash free dry mass with the five shell dimension parameters were all exponential (y = ax(b)). Among them, shell width and shell length were more precise (the average percentage error between observed and predicted value being 22.0% and 22.5%, respectively) than the other three parameters in the conversion of dry mass. Wet mass with shell could be directly converted to tissue dry mass and ash free dry mass, with an average percentage error of 21.7%. According to the essence of definition and the errors of conversion, ash free dry mass would be the optimum parameter to express snail biomass.

Nontraditional protein sources and their effect on growth and survival, during masculinization, of the fish Cichlasoma urophthalmus (Perciformes: Cichlidae)

OpenAIRE

Cuenca-Soria, Carlos A.; Navarro Angulo, Leonardo I.; Castillo-Domínguez, Alfonso; Melgar Valdes, Carolina E.; Pérez-Palafox, Xchel A.; Ortiz-Hernández, Mateo

2016-01-01

In Southeastern Mexico, aquaculture has been seriously affected by the high costs of commercial food. As part of the search for alternative foods we tested the freshwater fish Astyanax aeneus and the snail Pomacea flagellata as possible protein sources for Cichlasoma urophthalmus. We applied fluoxymesterone androgenic hormone for 45 days. One kilogram of experimental food (P. flagellate/A. aeneus) and one of commercial food were sprayed with solution of fluoxymesterone/absolute ethanol, at 5m...

Fecundity of the Chinese mystery snail in a Nebraska reservoir

Science.gov (United States)

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.

Biological control of the snail hosts of schistosomiasis in areas of low transmission: the example of the Caribbean area.

Science.gov (United States)

Pointier, J P; Jourdane, J

2000-10-23

The biological control of schistosomiasis has already proven its efficiency in several habitats in the Caribbean area. Two main types of biological control agents, either trematode parasites or competitor snails have been studied and tested against the snail hosts of schistosomiasis in this region. The first one, Ribeiroia guadeloupensis, a trematode sterilizing Biomphalaria glabrata was successfully tested in a Guadeloupean pond housing a natural population of B. glabrata. The second agent involves several species of competitor snails belonging to the Ampullariidae (Pomacea glauca, Marisa cornuarietis) and Thiaridae (Tarebia granifera, Melanoides tuberculata) families. Ampullarid snails were tested with success in several West Indian islands such as Guadeloupe. Thiarid snails have also proven their efficiency but also their limits in several types of habitats in Guadeloupe, Martinique, St. Lucia and Venezuela. Competitor snails have also proven to be useful in preventing the recolonization by the snail hosts after molluscicide treatments. The case of the rivers of the littoral central part of Venezuela is particularly relevant to this issue. The island of Martinique also constitutes a good example of the importance of competitor snails in a post-transmission phase of schistosomiasis control. This island is a well-developed country where schistosomiasis transmission was interrupted in the 1970s. However, the reactivation of some transmission sites was observed in the 1980s. The introduction of M. tuberculata into these sites resulted in the interruption of transmission and the near total disappearance of the snail hosts. Presently, the thiarid snails have colonized the whole Martinican hydrographic system and maintain dense populations preventing an eventual recolonization by the planorbid snails and thus are maintaining a sustainable control.

Contribution of Golden Apple Snail Flour to Enhance Omega- 3 and Omega-6 Fatty Acids Contents in Weaning Food

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Marsyha, D. D.; Wijayanti, H. S.; Nuryanto; Anjani, G.

2018-02-01

The case of undernourished children in Grobogan District (15.3%) is caused by children nutrients intake less than the Recommendation Dietary Allowance (RDA). To enhance children nutrients intake, be required formulation of weaning food using high-nutrient local food such as golden apple snail (Pomacea canaliculata). Golden apple snail flour contains high contents of zinc, iron, omega-3 and omega-6 fatty acids. This study aims to analyze the effect of golden apple snail flour substitution on nutrients content and organoleptic properties of weaning food (baby porridge). This is an experimental research by substitution of golden apple snail flour in the making of weaning food with four treatments of substitution (0%, 5%, 10%, 15%). Substitution of golden apple snails flour could affect the nutrient content levels of fat, zinc, iron (p=0.0001), carbohydrate (p=0.011), water (p=0.003), ash (p=0.001), omega-3 and omega-6 fatty acids. Whereas, it could not affect the content of energy (p=0.678), protein (p=0.129) and fiber (p=0.482). Furthermore, the substitution could affect the organoleptic properties include color, texture and taste (p=0.0001) while not for the aroma (p=0.798). Based on nutrient content analysis, substitution of golden apple snail flour could enhance the zinc, iron, omega-3 and omega-6 fatty acids contents of weaning food.

Invasive snails and an emerging infectious disease: results from the first national survey on Angiostrongylus cantonensis in China.

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Shan Lv

Full Text Available BACKGROUND: Eosinophilic meningitis (angiostrongyliasis caused by Angiostrongylus cantonensis is emerging in mainland China. However, the distribution of A. cantonensis and its intermediate host snails, and the role of two invasive snail species in the emergence of angiostrongyliasis, are not well understood. METHODOLOGY/PRINCIPAL FINDINGS: A national survey pertaining to A. cantonensis was carried out using a grid sampling approach (spatial resolution: 40x40 km. One village per grid cell was randomly selected from a 5% random sample of grid cells located in areas where the presence of the intermediate host snail Pomacea canaliculata had been predicted based on a degree-day model. Potential intermediate hosts of A. cantonensis were collected in the field, restaurants, markets and snail farms, and examined for infection. The infection prevalence among intermediate host snails was estimated, and the prevalence of A. cantonensis within P. canaliculata was displayed on a map, and predicted for non-sampled locations. It was confirmed that P. canaliculata and Achatina fulica were the predominant intermediate hosts of A. cantonensis in China, and these snails were found to be well established in 11 and six provinces, respectively. Infected snails of either species were found in seven provinces, closely matching the endemic area of A. cantonensis. Infected snails were also found in markets and restaurants. Two clusters of A. cantonensis-infected P. canaliculata were predicted in Fujian and Guangxi provinces. CONCLUSIONS/SIGNIFICANCE: The first national survey in China revealed a wide distribution of A. cantonensis and two invasive snail species, indicating that a considerable number of people are at risk of angiostrongyliasis. Health education, rigorous food inspection and surveillance are all needed to prevent recurrent angiostrongyliasis outbreaks.

Invasive Snails and an Emerging Infectious Disease: Results from the First National Survey on Angiostrongylus cantonensis in China

Science.gov (United States)

Lv, Shan; Zhang, Yi; Liu, He-Xiang; Hu, Ling; Yang, Kun; Steinmann, Peter; Chen, Zhao; Wang, Li-Ying; Utzinger, Jürg; Zhou, Xiao-Nong

2009-01-01

Background Eosinophilic meningitis (angiostrongyliasis) caused by Angiostrongylus cantonensis is emerging in mainland China. However, the distribution of A. cantonensis and its intermediate host snails, and the role of two invasive snail species in the emergence of angiostrongyliasis, are not well understood. Methodology/Principal Findings A national survey pertaining to A. cantonensis was carried out using a grid sampling approach (spatial resolution: 40×40 km). One village per grid cell was randomly selected from a 5% random sample of grid cells located in areas where the presence of the intermediate host snail Pomacea canaliculata had been predicted based on a degree-day model. Potential intermediate hosts of A. cantonensis were collected in the field, restaurants, markets and snail farms, and examined for infection. The infection prevalence among intermediate host snails was estimated, and the prevalence of A. cantonensis within P. canaliculata was displayed on a map, and predicted for non-sampled locations. It was confirmed that P. canaliculata and Achatina fulica were the predominant intermediate hosts of A. cantonensis in China, and these snails were found to be well established in 11 and six provinces, respectively. Infected snails of either species were found in seven provinces, closely matching the endemic area of A. cantonensis. Infected snails were also found in markets and restaurants. Two clusters of A. cantonensis–infected P. canaliculata were predicted in Fujian and Guangxi provinces. Conclusions/Significance The first national survey in China revealed a wide distribution of A. cantonensis and two invasive snail species, indicating that a considerable number of people are at risk of angiostrongyliasis. Health education, rigorous food inspection and surveillance are all needed to prevent recurrent angiostrongyliasis outbreaks. PMID:19190771

Ecotoxicological assessment of the impact of fluoride (F-) and turbidity on the freshwater snail Physella acuta in a polluted river receiving an industrial effluent.

Science.gov (United States)

Camargo, Julio A; Alonso, Álvaro

2017-06-01

We carried out field studies and laboratory experiments to assess the impact of fluoride (F - ) and turbidity on the freshwater snail Physella acuta in a polluted river receiving an industrial effluent (the middle Duraton River, Central Spain). Fluoride concentrations and turbidity levels significantly increased downstream from the industrial effluent (with the highest values being 0.6 mg F - /L and 55.2 nephelometric turbidity unit). In addition, higher deposition of fine inorganic matter was evident at polluted sampling sites. Conversely, the abundance of P. acuta significantly declined (until its virtual disappearance) downstream from the industrial effluent. Toxicity bioassays showed that P. acuta is a relatively tolerant invertebrate species to fluoride toxicity, with estimated safe concentrations (expressed as LC 0.10 values for infinite hours of exposure) for juvenile and adult snails being 2.4 and 3.7 mg F - /L, respectively. Furthermore, juvenile snails (more sensitive than adult snails) did not show significant alterations in their behavior through 15 days of exposure to 2.6 mg F - /L: mean values of the proportion of test snails located on the water surface habitat, as well as mean values of the sliding movement rate (velocity) of test snails, never showed significant differences when comparing control and treatment glass vessels. It is concluded that instream habitat degradation, derived from increased turbidity levels, might be a major cause for significant reductions in the abundance of P. acuta downstream from the industrial effluent. The presence of the competing gastropod Ancylus fluviatilis could also affect negatively the recovery of P. acuta abundance.

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

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Juan A Cueto

Full Text Available 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

Effects of chronic waterborne nickel exposure on growth, ion homeostasis, acid-base balance, and nickel uptake in the freshwater pulmonate snail, Lymnaea stagnalis.

Science.gov (United States)

Niyogi, Som; Brix, Kevin V; Grosell, Martin

2014-05-01

The freshwater pulmonate snail, Lymnaea stagnalis, is the most sensitive aquatic organism tested to date for Ni. We undertook a series of experiments to investigate the underlying mechanism(s) for this observed hypersensitivity. Consistent with previous experiments, juvenile snail growth in a 21-day exposure was reduced by 48% relative to the control when exposed to 1.3 μg l(-1) Ni (EC20 less than the lowest concentration tested). Ca(2+) homeostasis was significantly disrupted by Ni exposure as demonstrated by reductions in net Ca(2+) uptake, and reductions in Ca(2+) concentrations in the hemolymph and soft tissues. We also observed reduced soft tissue [Mg(2+)]. Snails underwent a significant alkalosis with hemolymph pH increasing from 8.1 to 8.3 and hemolymph TCO2 increasing from 19 to 22 mM in control versus Ni-exposed snails, respectively. Unlike in previous studies with Co and Pb, snail feeding rates were found to be unaffected by Ni at the end of the exposure. Snails accumulated Ni in the soft tissue in a concentration-dependent manner, and Ni uptake experiments with (63)Ni revealed a biphasic uptake profile - a saturable high affinity component at low exposure concentrations (36-189 nM) and a linear component at the high exposure concentrations (189-1,897 nM). The high affinity transport system had an apparent Km of 89 nM Ni(2+) and Vmax of 2.4 nmol g(-1)h(-1). This equates to a logK of 7.1, significantly higher than logK's (2.6-5.2) for any other aquatic organisms evaluated to date, which will have implications for Biotic Ligand Model development. Finally, pharmacological inhibitors that block Ca(2+) uptake pathways in snails did not inhibit Ni uptake, suggesting that the uptake of Ni does not occur via Ca(2+) uptake pathways. As with Cu and Pb, the exact mechanism for the significant disruption in Ca(2+) homeostasis and reduction in juvenile snail growth remains unknown. Copyright © 2014 Elsevier B.V. All rights reserved.

On Pomacea canaliculata (Lamarck, 1822 (Mollusca; Pilidae: Ampullariidae

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Silvana C. Thiengo

1993-03-01

Full Text Available This paper deals with the morphology of Pomacea caniculata (Lamarck, 1822 collected at Corrientes, Argentina. Comparison is made with Pomacea lineata (Spix, 1827 and Pomacea sordida (Swainson, 1823. The shell is globose, heavy, with greenish or horn-colored periostracum and dark spiral bands; apex subelevated, 5-6 whorls increasing rather rapidly and separated by very deep suture. Aperture large, rounded to subelongated; lip sometimes reddish; umbilicus large and deep; operculum corneous, entirely closing the aperture. Ratios: shell width/shell length = 0.78-0.96 (mean 0.86; aperture length/shell length = 0.68-0.77 (mean 0.72. Radula similar to other congeneric species. Testis and spermiduct as in P. lineata and P. sordida; prostate cylindric and short, cream in color as the testis. Penial sheath straight bearing a central outer gland deeply embedded in the tissue of its basal portion and a large wrinkled gland occupying 2/3 of the distal tip of its inner surface; the rigth margin of the sheath overlaps the left one until 2/3 of its proximal end. Female reproductive apparatus similar to that P. lineata; vestigial male copulatory apparatus (penis and its sheath present in all females examined.

First proteome of the egg perivitelline fluid of a freshwater gastropod with aerial oviposition

KAUST Repository

Sun, Jin

2012-08-03

Pomacea canaliculata is a freshwater snail that deposits eggs on solid substrates above the water surface. Previous studies have emphasized the nutritional and protective functions of the three most abundant perivitelline fluid (PVF) protein complexes (ovorubin, PV2, and PV3) during its embryonic development, but little is known about the structure and function of other less abundant proteins. Using 2-DE, SDS-PAGE, MALDI TOF/TOF, and LC-MS/MS, we identified 59 proteins from the PVF of P. canaliculata, among which 19 are novel. KEGG analysis showed that the functions of the majority of these proteins are "unknown" (n = 34), "environmental information processing" (10), 9 of which are related to innate immunity, and "metabolism" (7). Suppressive subtractive hybridization revealed 21 PVF genes to be specific to the albumen gland, indicating this organ is the origin of many of the PVF proteins. Further, the 3 ovorubin subunits were identified with 30.2-35.0% identity among them, indicating their common origin but ancient duplications. Characterization of the PVF proteome has opened the gate for further studies aiming to understand the evolution of the novel proteins and their contribution to the switch to aerial oviposition. © 2012 American Chemical Society.

Freshwater snail distribution related to environmental factors in ...

African Journals Online (AJOL)

This station which received domestic sewage from the neighbouring cities was characterized by the highest conductivity and pH and the lowest values of dissolved oxygen. Multiple stepwise regression analysis showed that snail densities were probably influenced by conductivity, dissolved oxygen, pH, and canopy cover.

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

Science.gov (United States)

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) 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.

Desarrollo morfológico e histológico del sistema reproductor de Pomacea patula catemacensis (Baker 1922 (Mollusca, Caenogastropoda: Ampullariidae Morphological and histological development of the reproductive system of Pomacea patula catemacensis (Baker 1922 (Mollusca, Caenogastropoda: Ampullariidae

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AURA CARREÓN-PALAU

2003-12-01

Full Text Available El "tegogolo" Pomacea patula catemacensis es un gasterópodo dulceacuícola comestible, endémico del Lago de Catemaco en Veracruz, México. En los últimos años las poblaciones naturales se han visto diezmadas debido a que su captura se realiza sin control, a lo que se suma el alto grado de deterioro ambiental que presenta el lago, producto del "azolvamiento", así como por la contaminación por plaguicidas y detergentes. El objetivo del presente estudio fue caracterizar histológica y morfológicamente el sistema reproductor de P. patula catemacensis y determinar las etapas de madurez gonádica en condiciones de laboratorio. Se determinó que la maduración depende de la talla y no de la edad de los organismos, y se identificaron cuatro etapas principales en el desarrollo de machos y hembras: Los estadios y sus longitudes promedio ± intervalo de confianza del 95 % son (1 inmadura o indiferenciada (talla de 0,72 a 7 mm, (2 maduración temprana (18,95 ± 1,96 mm, (3 maduración intermedia (29,29 ± 4,9 mm y (4 madurez total (35,89 ± 3,92 mm. En este molusco los sexos están separados, la fertilización es interna y el desarrollo es ovovivíparo. En las hembras la secreción de albúmina y de carbonato de calcio se realiza en la glándula de la albúmina, característica en la que difiere de otras especies como P. paludosa y P. canaliculata, las cuales poseen además glándula de la cápsula. Es posible identificar el grado de madurez de los caracoles utilizando criterios anatómicos visuales, como la glándula de la albúmina, en el caso de la hembra, y el órgano copulador en el machoThe "apple snail" Pomacea patula catemacensis is an edible freshwater mollusc, endemic to the Catemaco Lake in Veracruz, Mexico. During the past few years, the natural populations of this species have been depleted mainly by uncontrolled fishery, and because of environmental degradation and pollution by pesticides and detergents. In the present study, we carried

Novel estrogen receptor-related Transcripts in Marisa cornuarietis; a freshwater snail with reported sensitivity to estrogenic chemicals.

Science.gov (United States)

Bannister, Richard; Beresford, Nicola; May, Denise; Routledge, Edwin J; Jobling, Susan; Rand-Weaver, Mariann

2007-04-01

We have isolated novel molluskan steroid receptor transcripts orthologous to vertebrate estrogen receptors (ERs) and estrogen receptor-related receptors (ERRs) from the freshwater snail Marisa cornuarietis. Radiolabeled ligand binding analyses showed that neither recombinant receptor protein specifically bound 17beta-estradiol over the range applied (0.3-9.6 nM). These novel receptor transcripts have thus been designated mcER-like and mcERR respectively. Quantitative PCR revealed mcER-like to be expressed ubiquitously throughout a range of male and female structures studied, including neural and reproductive tissues. Highest absolute levels were seen in the male penis-sheath complex. The mcERR mRNA was also expressed ubiquitously throughout all male and female tissues analyzed here, with very low absolute transcript numbers in female accessory sex structures compared to other tissues.

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

Science.gov (United States)

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 (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.

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

International Nuclear Information System (INIS)

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

2014-01-01

Silver nanoparticles (AgNPs) are widely used in many applications and likely released into the aquatic environment. There is increasing evidence that Ag is efficiently delivered to aquatic organisms from AgNPs after aqueous and dietary exposures. Accumulation of AgNPs through the diet can damage digestion and adversely affect growth. It is well recognized that aspects of water quality, such as hardness, affect the bioavailability and toxicity of waterborne Ag. However, the influence of water chemistry on the bioavailability and toxicity of dietborne AgNPs to aquatic invertebrates is largely unknown. Here we characterize for the first time the effects of water hardness and humic acids on the bioaccumulation and toxicity of AgNPs coated with polyvinyl pyrrolidone (PVP) to the freshwater snail Lymnaea stagnalis after dietary exposures. Our results indicate that bioaccumulation and toxicity of Ag from PVP-AgNPs ingested with food are not affected by water hardness and by humic acids, although both could affect interactions with the biological membrane and trigger nanoparticle transformations. Snails efficiently assimilated Ag from the PVP-AgNPs mixed with diatoms (Ag assimilation efficiencies ranged from 82 to 93%). Rate constants of Ag uptake from food were similar across the entire range of water hardness and humic acid concentrations. These results suggest that correcting regulations for water quality could be irrelevant and ineffective where dietary exposure is important. - Highlights: • AgNP coated with polyvinyl pyrrolidone (PVP), PVP-AgNP were efficiently assimilated by Lymnaea stagnalis. • Water chemistry has no influence on the dietary uptake of PVP-AgNP by snails. - L. Stagnalis assimilated PVP-AgNPs efficiently from food and water chemistry had no influence on their uptake and toxicity

On Pomacea sordida (Swainson, 1823 (Prosobranchia, Ampullariidae Sobre Pomacea sordida (Swaison, 1823 (Prosobranchia, Ampullariidae

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Silvana Carvalho Thiengo

1989-09-01

Full Text Available A description of Pomacea sordida (Swainson, 1823 collected in Caxias and Nova Iguaçu, state of Rio de Janeiro, is presented. The shell is globose, heavy, whith greenish or horn-colored periostracum and dark spinal bands; apex subelevated, 4-5 moderately shoudered whorls, increasing rather rapidly and separated by deep suture. Aperture large, moderately round, yellowish or violaceous; lip thick and sometimes dark brown; umbilicus large and deep; operculum corneous and heavy, entirely closing the aperture. Ratios: shell width/shell length = 0.81-0.91 (mean 0.86; aperture length/shell length = 0.66-0.75 (mean 0.70. Testis, spermiduct and penis pouch as in Pomacea lineata (Spix, 1827. Seminal vesicle whitish and bean-shaped. Prostate cylindric and narrow, cream in coloar as the testis. Penis whiplike whith a closed circular spermiduct. Penial sheath elongated and tapered, with its distal tip turned to the right; outer basal gland situated on the left; inner median gland rounded; apical gland elongated and wrinkled. Ovary composed of branched whitish tubules lying superficially on the digestive gland; oviduct and seminal receptacle as in P. lineata; albumen gland yellowish - orange. Vestigial male copulatory apparatus (penis and its sheath present in all females examined.Nesse trabalho é apresentada a descrição de Pomacea sordida (Swainson, 1823, coletada em Caxias e Nova Iguaçu, Estado do Rio de Janeiro. Concha globosa, espessa, com perióstraco esverdeado ou castanho e com faixas espirais escuras; ápice pouco elevado, 4-5 giros moderadamente arredondados, crescendo relativamente rápido, separados por suturas profundas. Abertura grande, moderadamente arredondada, amarelada ou violácea; lábio espesso e algumas vezes marrom escuro; umbílico grande e profundo; opérculo córneo e espesso, fechando completamente a abertura. Razões: largura da concha/comprimento da concha=0.81-0.91 (média 0.86; comprimento da abertura/comprimento da concha=0

Molecular diversity of avian schistosomes in Danish freshwater snails

DEFF Research Database (Denmark)

Christiansen, Anne Ø.; Olsen, Annette; Buchmann, Kurt

2016-01-01

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 ...

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

Science.gov (United States)

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

2007-02-01

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

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

Science.gov (United States)

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

2014-01-01

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

Redescription of Temnocephala iheringi (Platyhelminthes: Temnocephalida based on specimens from Pomacea canaliculata (Mollusca: Ampullariidae of the state of Rio Grande do Sul, Brazil: the possible type host and type locality

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Samantha A. Seixas

2010-04-01

Full Text Available The original description of Temnocephala iheringi Haswell, 1893 was based on specimens collected by Hermann von Ihering from undetermined ampullariid apple snails, which at that time were identified as Ampullaria sp., and sent to William H. Haswell, with the type locality simply indicated as Brazil. The type specimens studied by Haswell were not found in the scientific collections of Brazil, Europe or Australia, and should be considered lost. In 1941, Pereira & Cuocolo collected specimens from apple snails, identified as Pomacea lineata (Spix in Wagner, 1827, at two localities (Guaicurús and Salobra in the state of Mato Grosso do Sul, central Brazil. These specimens could not be located either and should, thus, be considered lost as well. Pomacea canaliculata (Lamarck, 1822, the main host of T. iheringi in southern Brazil, is known to have a geographical distribution that reaches Uruguay and 400 km beyond the province of Buenos Aires, Argentina. Three hundred and one mollusks were collected from 1999 to 2007. Temnocephalans found in the pallial cavity presented a greenish body pigmentation (adults and lacked eye pigment of any color, including the red-eye pigment, typical of Neotropical species of Temnocephala Blanchard, 1849; straight cirrus, with a thick band at base of the introvert' swelling; and a single, circular, asymmetric vaginal sphincter, wider in diameter in the posterior portion. As the species occurs concurrently with two other species, at least in P. canaliculata from Rio Grande do Sul, the eggs of T. iheringi could not be reliably distinguished. A redescription of the species is provided. A comparison of data from the present work with those of earlier papers published on T. iheringi from Argentina showed that the Argentinean specimens had the smallest measurements.

[Radioecological studies of freshwater mollusks in the Chernobyl accident exclusion zone].

Science.gov (United States)

Gudkov, D I; Nazarov, A B; Dziubenko, E V; Kaglian, A E; Klenus, V G

2009-01-01

Species-specificity and dynamics of 90Sr, 137Cs and some transuranic elements accumulation in bivalve and gastropod freshwater molluscs of the Chernobyl exclusion zone during 1997-2008 was analyzed. The results of radiation dose and chromosome aberration rate estimation and the analysis of hemolymph composition of freshwater snail (Lymnaea stagnalis L.) was produced. The absorbed dose rate was registered in the range of 0.3-85.0 microGy/h. In closed water bodies the heightened chromosome aberration rate (up to 27%) in embryo tissues, and also the change of haematological indexes for the adult individuals of snails was registered.

First records of freshwater molluscs from the ecological reserve El Edén, Quintana Roo, México Primeros registros de moluscos dulceacuícolas de la Reserva Ecológica El Edén, Quintana Roo, México

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Roberto Cózatl-Manzano

2007-12-01

Full Text Available The diversity of the freshwater molluscs at El Edén was unknown. This is the first treatment of them, allowing us to compare spatial and temporal species distribution. Eleven species of freshwater molluscs were found in 2 surveys carried in March (dry season and September (rainy season 1998 at the reserve El Edén. A total of 266 individuals were collected; 8 pulmonates, Mayabina spiculata, Mexinauta impluviatus, Physa sp., Biomphalaria havanensis, Drepanotrema lucidum, Drepanotrema kermatoides, Planorbella (Pierosoma trivolvis, and Planorbula armigera; 2 prosobranchs, Pyrgophorus sp. and Pomacea flagellata; and one bivalve, Musculium transversum. Pulmonata dominate over Prosobranchia species in diversity. No significant differences were observed in diversity between dry and rainy seasons. However, species abundance recorded in both seasons was very low, probably due to a combination of inadequate food resources and disadvantageous climate (periodic conditions of drought and flooding. Further studies using a combination of different sampling methods and more frequent samplings are needed to confirm or identify these factors. We suggest that future studies should focus on cultivation of species with economic potential such as the apple snail Pomacea flagellata.La diversidad de moluscos dulceacuícolas de la Reserva Ecológica El Edén se desconocía; este estudio constituye su primer registro. Asimismo, esta investigación permite comparar la distribución espacial y temporal de las especies registradas. Las recolectas se efectuaron en marzo (temporada de sequía y septiembre (lluvia de 1998. Se registran 11 especies (266 individuos en total, 8 pulmonados: Mayabina spiculata, Mexinauta impluviatus, Physa sp., Biomphalaria havanensis, Drepanotrema lucidum, Drepanotrema kermatoides, Planorbella (Pierosoma trivolvis y Planorbula armigera; dos prosobranquios: Pyrgophorus sp. y Pomacea flagellata, y un bivalvo: Musculium transversum. Los pulmonados

Uptake and release of 65Zn and 124Sb by Biomphalaria alexandrina and Cleopatra bulimoides snails and their effects on the ultrastructure of the hermaphrodite gland

International Nuclear Information System (INIS)

Moloukhia, H.; Alian, A.

1999-01-01

The freshwater snails, are by far the most prevalent organisms among the local freshwater fauna, and represent an important group of mollusks, from the stand point of health and economy. This is due to he role played by many of them as hosts for certain parasites of man and his animals. These snails are rather considered pests and so their populations are currently controlled by several measures. On the other hand, various radioactive elements are increasingly detected in the aquatic environment, some of them may find their way to the freshwater ecosystems. So it became necessary to find any radiobioindicator from among the common aquatic biota that can be used to detect any radioactive disposal into the freshwater environment. This paper reports a radioactive tracer study on weather the previously mentioned snails can be used either in the biological treatment of low-level radioactive waste and/or as radiobioindicators

Effects of snails, submerged plants and their coexistence on eutrophication in aquatic ecosystems

OpenAIRE

Mo Shuqing; Zhang Xiufeng; Tang Yali; Liu Zhengwen; Kettridge Nicholas

2017-01-01

Eutrophication resulting from nutrient loading to freshwater habitats is a severe problem, leading to degradation of ecosystems, including deterioration of water quality, water clarity and loss of biodiversity. Measures enacted to restore degraded freshwater ecosystems often involve the reintroduction of submerged plants and aquatic animals with beneficial ecological functions. In a mesocosm experiment, three treatments (planting with Vallisneria natans, introduction of the snail Bellamya aer...

Micro-distribution of freshwater snails before and after water flow ...

African Journals Online (AJOL)

Bulinus truncatus the intermediate host of Schistosoma haematobium, is widely distributed in modern irrigation schemes in Morocco. These schemes have intermittent irrigation and canals dry out in between irrigation periods. The snail species is therefore associated with the 'siphon boxes' connecting canal segments, ...

Modelling climate change impact on the spatial distribution of fresh water snails hosting trematodes in Zimbabwe.

Science.gov (United States)

Pedersen, Ulrik B; Stendel, Martin; Midzi, Nicholas; Mduluza, Takafira; Soko, White; Stensgaard, Anna-Sofie; Vennervald, Birgitte J; Mukaratirwa, Samson; Kristensen, Thomas K

2014-12-12

Freshwater snails are intermediate hosts for a number of trematodes of which some are of medical and veterinary importance. The trematodes rely on specific species of snails to complete their life cycle; hence the ecology of the snails is a key element in transmission of the parasites. More than 200 million people are infected with schistosomes of which 95% live in sub-Saharan Africa and many more are living in areas where transmission is on-going. Human infection with the Fasciola parasite, usually considered more of veterinary concern, has recently been recognised as a human health problem. Many countries have implemented health programmes to reduce morbidity and prevalence of schistosomiasis, and control programmes to mitigate food-borne fascioliasis. As these programmes are resource demanding, baseline information on disease prevalence and distribution becomes of great importance. Such information can be made available and put into practice through maps depicting spatial distribution of the intermediate snail hosts. A biology driven model for the freshwater snails Bulinus globosus, Biomphalaria pfeifferi and Lymnaea natalensis was used to make predictions of snail habitat suitability by including potential underlying environmental and climatic drivers. The snail observation data originated from a nationwide survey in Zimbabwe and the prediction model was parameterised with a high resolution Regional Climate Model. Georeferenced prevalence data on urinary and intestinal schistosomiasis and fascioliasis was used to calibrate the snail habitat suitability predictions to produce binary maps of snail presence and absence. Predicted snail habitat suitability across Zimbabwe, as well as the spatial distribution of snails, is reported for three time slices representative for present (1980-1999) and future climate (2046-2065 and 2080-2099). It is shown from the current study that snail habitat suitability is highly variable in Zimbabwe, with distinct high- and low

Endemic angiostrongyliasis in the Brazilian Amazon: natural parasitism of Angiostrongylus cantonensis in Rattus rattus and R. norvegicus, and sympatric giant African land snails, Achatina fulica.

Science.gov (United States)

Moreira, V L C; Giese, E G; Melo, F T V; Simões, R O; Thiengo, S C; Maldonado, A; Santos, J N

2013-01-01

Angiostrongylus cantonensis, the rat lungworm, is one etiological agent of eosinophilic meningoencephalitis in humans. This zoonosis is frequently found in Asia and, more recently, in North America, Caribbean Island and northeastern of South America. Until now, research of A. cantonensis in southern, southeastern and northeastern regions of Brazil has been found natural infections only terrestrial and freshwater intermediate snail hosts (Achatina fulica, Sarasinula marginata, Subulina octona, Bradybaena similaris and Pomacea lineate). In this study, we examined the occurrence of helminthes in the synantropic rodents Rattus rattus and Rattus norvegicus in northern Brazil, focusing on the role of these species as vertebrate hosts of A. cantonensis and A. fulica as intermediate host have found natural. Thirty specimens of R. rattus and twelve of R. norvegicus were collected in the Guamá and Jurunas neighborhoods of the city of Belém, in the Brazilian state of Pará, of which almost 10% harbored adult worms in their pulmonary arteries. Sympatric A. fulica were found to be infected by L(3) larvae, which experimental infection confirmed to be A. cantonensis. Natural infection of snails and rodents with A. cantonensis was confirmed through morphological and morphometrical analyses of adults and larvae using light microscopy, scanning electron microscopy and molecular sequences of partial Cytochrome Oxidase subunit I. Phylogenetic analyses showed that A. cantonensis isolated from Pará, Brazil is similar to Japan isolate; once these specimens produced a single haplotype with high bootstrap support with Rio de Janeiro isolate. This study confirms that A. cantonensis is now endemic in northern Brazil, and that R. rattus and R. norvegicus act as natural definitive hosts, and A. fulica as the intermediate host of the parasite in this region. Copyright © 2012 Elsevier B.V. All rights reserved.

Effects of snails, submerged plants and their coexistence on eutrophication in aquatic ecosystems

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Mo Shuqing

2017-01-01

Full Text Available Eutrophication resulting from nutrient loading to freshwater habitats is a severe problem, leading to degradation of ecosystems, including deterioration of water quality, water clarity and loss of biodiversity. Measures enacted to restore degraded freshwater ecosystems often involve the reintroduction of submerged plants and aquatic animals with beneficial ecological functions. In a mesocosm experiment, three treatments (planting with Vallisneria natans, introduction of the snail Bellamya aeruginosa and a combined treatment with both plants and snails were compared with controls to evaluate their effects on trophic state. The total nitrogen (TN, total phosphorus (TP and chlorophyll a (Chl a concentrations of planktonic and benthic algal samples were determined every two weeks, along with light intensity at the sediment surface. The plant-only treatment significantly reduced the TN levels and planktonic and benthic algal biomass and increased the light intensity at the sediment surface. The snail-only treatment reduced the concentrations of TN and reduced planktonic and benthic algal biomass. The combined treatment decreased the concentrations of TN and TP, reduced planktonic algal biomass and increased the light intensity on the sediment surface. The results indicate that while submerged plants and snails can both improve water quality, the most pronounced effect in aquatic ecosystems is achieved by their presence in combination. A combined reintroduction approach may provide enhanced benefits in restoring the eutrophic ecosystems, following the reduction of external nutrient loading.

Distribution, habitats and role as intermediate host of the freshwater snail, Bulinus forskalii, in South Africa

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K.N. De Kock

2005-09-01

Full Text Available This paper focuses on the geographical distribution and habitats of Bulinus forskalii, the snail intermediate host of the conical fluke of equids, Gastrodiscus aegyptiacus as reflected by the 1 209 samples in the database of the National Freshwater Snail Collection of South Africa. The 362 different loci on record represent an extensive distribution in KwaZulu-Natal Province, the Limpopo Province, the coastal areas of the Eastern Cape Province and the south-eastern part of the North West Province. Although it was recorded from all types of water-body represented in the database, the highest percentages of samples were recovered from dams (30.4 % and brooks (28.2 %. The majority of samples came from perennial habitats (59.1%, 60.7% from habitats with standing water, 54.0 % from habitats with clear water and 71.8 % from habitats of which the water was described as fresh. The majority of samples (39.5 % were collected in habitats of which the substratum was recorded as muddy. The highest percentage of samples, by far (81.5 %, was collected in habitats that fell within the mean yearly temperature interval ranging from 15-20 °C. An integrated decision tree constructed from the data in the database indicated that temperature and type of water-body played a decisive role in determining the presence of B. forskalii in a given area. The results of experimental exposure to miracidia of a local strain of both Schistosoma haematobium and Schistosoma mattheei in the laboratory indicated that a local strain of B. forskalii was incompatible with both these strains of parasite. Research to clarify the role of B. forskalii in the transmission of both Calicophoron microbothrium and G. aegyptiacus in South Africa, is recommended.

A malacological survey in the Manso Power Plant, State of Mato Grosso, Brazil: new records of freshwater snails, including transmitters of schistosomiasis and exotic species

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Monica Ammon Fernandez

2014-07-01

Full Text Available Introduction Schistosomiasis is a parasitic disease of public health concern in Brazil, and the construction of hydroelectric dams, in addition to increasing permanent human settlement and tourism, has created conditions suitable for the establishment of mollusks that can transmit schistosomiasis. Such areas require a number of actions to prevent the establishment of schistosomiasis. This paper reports on a freshwater malacological survey carried out in the geographical area of the Manso Power Plant. Methods Mollusks were collected in 18 municipalities in the State of Mato Grosso between February 2002 and February 2004 (qualitative study and from April 2009 to February 2011 (quantitative study. Results Thirty-one species of mollusks were collected, including newly recorded species (Antillorbis nordestensis and Burnupia ingae. In addition, the geographic distributions of known species, including Biomphalaria straminea, a snail vector of Schistosoma mansoni, were expanded. A total of 4,507 specimens were collected in the APM Manso reservoir (Usina Hidrelétrica de Aproveitamento Múltiplo de Manso during the quantitative study, and Biomphalaria amazonica was found in six of the 10 localities analyzed. The Afroasiatic species Melanoides tuberculata, introduced after February 2009, was the dominant species (relative abundance 94.96%. Conclusions The study area is epidemiologically important due to the occurrence of B. straminea and B. amazonica, which are vectors of schistosomiasis, and M. tuberculata, a snail host of Centrocestus formosanus, which is responsible for centrocestiasis transmission. Observations of M. tuberculata and the exotic freshwater clams Corbicula fluminea and Corbicula largillierti raise concerns about biodiversity.

Feeding behavior of black carp Mylopharyngodon piceus (Pisces: Cyprinidae) on fry of other fish species and trematode transmitting snail species

DEFF Research Database (Denmark)

Hung, Nguyen Manh; The, Dang Tat; Stauffer, Jay R.

2014-01-01

Fish raised in aquaculture ponds may get infected with fishborne zoonotic trematodes (FZT) during the nursing stage. Freshwater snails serve as intermediate hosts for FZT and we wanted to explore the possibility of controlling snails by stocking nursery ponds with a few juvenile specimens...

Survival and growth of freshwater pulmonate and nonpulmonate snails in 28-day exposures to copper, ammonia, and pentachlorophenol

Science.gov (United States)

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.

Tissue distributions and seasonal dynamics of the hepatotoxic microcystins-LR and -RR in a freshwater snail (Bellamya aeruginosa) from a large shallow, eutrophic lake of the subtropical China

International Nuclear Information System (INIS)

Chen Jun; Xie Ping; Guo Longgen; Zheng Li; Ni Leyi

2005-01-01

Tissue distributions and seasonal dynamics of the hepatotoxic microcystins-LR and -RR in a freshwater snail (Bellamya aeruginosa) were studied monthly in a large shallow, eutrophic lake of the subtropical China during June-November, 2003. Microcystins (MCs) were quantitatively determined by High-Performance Liquid Chromatography (HPLC) with a qualitative analysis by a Finnigan LC-MS system. On the average of the study period, hepatopancreas was the highest in MC contents (mean 4.14 and range 1.06-7.42 μg g -1 DW), followed by digestive tracts (mean 1.69 and range 0.8-4.54 μg g -1 DW) and gonad (mean 0.715 and range 0-2.62 μg g -1 DW), whereas foot was the least (mean 0.01 and range 0-0.06 μg g -1 DW). There was a positive correlation in MC contents between digestive tracts and hepatopancreas. A constantly higher MC content in hepatopancreas than in digestive tracts indicates a substantial bioaccumulation of MCs in the hepatopancreas of the snail. The average ratio of MC-LR/MC-RR showed a steady increase from digestive tracts (0.44) to hepatopancreas (0.63) and to gonad (0.96), suggesting that MC-LR was more resistant to degradation in the snail. Since most MCs were present in the hepatopancreas, digestive tracts and gonad with only a very small amount in the edible foot, the risk to human health may not be significant if these toxic parts are removed prior to snail consumption. However, the possible transference of toxins along food chains should not be a negligible concern. - Snails bioaccumulate microcystins in their hepatopancreas, gut and gonad, posing a risk to human consumers

Identification and Profiling of Active Compounds from Golden Apple Snail’s Egg Pigments

Directory of Open Access Journals (Sweden)

Asadatun Abdullah

2017-08-01

Full Text Available Golden apple snail (Pomacea canaliculata has been known as rice corps pest due to high adaptability and reproductive power. Utilization of Pomacea canaliculata’s eggs as raw materials in the food and health industry is one of the efforts to eradicate the pest snail. This study was aimed to identify the active compounds contained in the extract pigments of Pomacea canaliculata’s eggs. The methods of this study were extraction of pigments using acetone and methanol, analyzing the active compound (secondary metabolite qualitatively, TLC to determine pigment components and LC-MS/MS to identify active compounds semi quantitatively. The results showed that active compounds in the methanol extract contain 11 carotenoid pigments of xanthophyl group, two carotenoid pigments of carotene group, and 2 active compounds in nonpigmented form, whereas the acetone extract contain 11 pigmentcarotenoids of xanthophyl group and 2 compounds active in non-pigment form.

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

Science.gov (United States)

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.

Egg extract of apple snail for eco-friendly synthesis of silver nanoparticles and their antibacterial activity.

Science.gov (United States)

Janthima, Ratima; Khamhaengpol, Arunrat; Siri, Sineenat

2018-03-01

Green synthesis of silver nanoparticles (AgNPs) provides the alternative method with cost effectiveness and the eco-friendly process by using natural biomolecules as reducing and stabilizing agents. Alternative to the most studies of plant extracts, this work demonstrated a use of egg extract of apple snail (Pomacea canaliculata) for an eco-friendly production of AgNPs. The extract contained at least six proteins with the molecular weight in a range of 24-65 kDa that exhibited the reducing activity. The dispersive AgNPs were produced in the reaction containing only the extract and silver nitrate, as determined by the characteristic surface plasmon resonance peak of silver at 412 nm. The synthesized AgNPs were spherical with the average diameter of 9.0 ± 5.9 nm. The X-ray diffraction pattern and selected area electron diffraction (SAED) analyses confirmed the face-cubic centre (fcc) unit cell structure of AgNPs. The synthesized AgNPs exhibited the antibacterial activity against both Gram-positive Staphylococcus aureus and Gram-negative Escherichia coli. Results of this work clearly showed the potential use of the egg extract of apple snail for a green synthesis of small size AgNPs exhibiting the antibacterial activity.

Snail abundance in freshwater canals in the eastern province of ...

African Journals Online (AJOL)

Ksu-network

2012-07-19

Jul 19, 2012 ... Recent Advances in Freshwater Biology. New Delhi. Anmol. Publication. Vol. 2. pp. 187-202. Al-Akel and Suliman. 12261. Supian Z, Ikhwanuddin AM (2002). Population dynamics of freshwater mollusks (Gastropod: Melanoides Tuberculatus) in crocker range park, Sabah. ASEAN Rev. Biodiv. Environ.

Reproductive characterization of three species of Giant African land ...

African Journals Online (AJOL)

Administrator

2011-09-05

Sep 5, 2011 ... wild lay eggs about two to three times per season. (Cobbinah et al., 2008). ... courtship and copulatory duration of three (3) species of. Giant African land ... digital stop watch and the snails were observed from 6.00 pm to. 7.00 am daily ..... trail following in apple snail, Pomacea canaliculata. J. Mollusc stud.

Evidence for non-assimilation of Chlorella by the African freshwater snail Bulinus (Physopsis) globosus

International Nuclear Information System (INIS)

Van Aardt, W.J.; Wolmarans, C.T.

1981-01-01

Little is known about the assimilation of its natural food by South African basommatophorans. It is generally assumed that the snails are microphagus herbivores which ingest mainly periphytic algae, detritus and the bacterial component of their food. Preliminary observations indicated that Chlorella spp. were by far the dominant algal species on stems and leaves of Juncus on which the snails were usually found in our study. This report describes experiments to see whether Chlorella is ingested and assimilated by Bulinus (Physopsis) globosus. A closely related species, B. (B.) tropicus, which occupies the same niche was also included in the study for purposes of comparison. It was found that, although Chlorella was continuously ingested by both species, it was assimilated by neither. Possible reasons for this are given

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

Science.gov (United States)

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

Population genetic structure of the freshwater snail, Bulinus globosus, (Gastropoda: Planorbidae) from selected habitats of KwaZulu-Natal, South Africa.

Science.gov (United States)

Mkize, Lwamkelekile Sitshilelo; Mukaratirwa, Samson; Zishiri, Oliver Tendayi

2016-09-01

The freshwater snail Bulinus globosus is an important intermediate host of Schistosoma haematobium, the causative agent of urinary schistosomiasis. This disease is of major health concern, especially in Africa where the majority of cases have been reported. In this study the inter- and intra-genetic diversity and population genetic structure of B. globosus from nine locations in the KwaZulu-Natal province of South Africa was studied using four polymorphic microsatellite loci (BgZ1-BgZ4). Moderate genetic diversity was detected within populations with a mean diversity (HE) of 0.49±0.09. The majority of populations significantly deviated from Hardy-Weinberg equilibrium (p<0.05), due to a deficit of heterozygotes. Such deviations may be due to founder events that were caused by bottlenecks that occurred as a result of frequent droughts and flooding that these snails' habitats are exposed to. Overall, the populations studied seem to be partially inbreeders/selfers with mean estimates of 0.24/0.38. A discernable genetic structure was elucidated among populations as evident by the mean pairwise FST of 0.58±0.13. There was no significant association between genetic and geographical distance among populations, an indication of limited gene flow. This increases the chances of populations losing alleles due to genetic drift. Populations in close proximity demonstrated high genetic differentiation (58.77% total variation) due to allelic differences between them. The sample populations fell into 12 clusters, however, the populations from uMkhanyakude and uThungulu exhibited no discernable genetic structure. Genetically, the Bhobhoyi site found within the uGu district was equidistant to the two main sampling regions. Copyright © 2016 Elsevier B.V. All rights reserved.

A faunistic survey of digenean larvae infecting freshwater snails ...

African Journals Online (AJOL)

Biomphalaria and Bulinus spp have been reported in Tanzania as vectors of Schistosoma mansoni and Schistosoma haematobium respectively. Thus most schistosomiasis control efforts have focussed on elimination of these molluscs in freshwater systems or deworming infected persons. In addition almost there is limited ...

Impact of the redox-cycling herbicide diquat on transcript expression and antioxidant enzymatic activities of the freshwater snail Lymnaea stagnalis

Energy Technology Data Exchange (ETDEWEB)

Bouetard, Anthony, E-mail: anthony.bouetard@rennes.inra.fr [INRA, UMR INRA-Agrocampus Ouest ESE 0985, Equipe Ecotoxicologie et Qualite des Milieux Aquatiques, 65 rue de Saint-Brieuc, 35042 Rennes cedex (France); Besnard, Anne-Laure; Vassaux, Daniele; Lagadic, Laurent; Coutellec, Marie-Agnes [INRA, UMR INRA-Agrocampus Ouest ESE 0985, Equipe Ecotoxicologie et Qualite des Milieux Aquatiques, 65 rue de Saint-Brieuc, 35042 Rennes cedex (France)

2013-01-15

The presence of pesticides in the environment results in potential unwanted effects on non-target species. Freshwater organisms inhabiting water bodies adjacent to agricultural areas, such as ditches, ponds and marshes, are good models to test such effects as various pesticides may reach these habitats through several ways, including aerial drift, run-off, and drainage. Diquat is a non-selective herbicide used for crop protection or for weed control in such water bodies. In this study, we investigated the effects of diquat on a widely spread aquatic invertebrate, the holarctic freshwater snail Lymnaea stagnalis. Due to the known redox-cycling properties of diquat, we studied transcript expression and enzymatic activities relative to oxidative and general stress in the haemolymph and gonado-digestive complex (GDC). As diquat is not persistent, snails were exposed for short times (5, 24, and 48 h) to ecologically relevant concentrations (22.2, 44.4, and 222.2 {mu}g l{sup -1}) of diquat dibromide. RT-qPCR was used to quantify the transcription of genes encoding catalase (cat), a cytosolic superoxide dismutase (Cu/Zn-sod), a selenium-dependent glutathione peroxidase (gpx), a glutathione reductase (gred), the retinoid X receptor (rxr), two heat shock proteins (hsp40 and hsp70), cortactin (cor) and the two ribosomal genes r18S and r28s. Enzymatic activities of SOD, Gpx, Gred and glutathione S-transferase (GST) were investigated in the GDC using spectrophoto/fluorometric methods. Opposite trends were obtained in the haemolymph depending on the herbicide concentration. At the lowest concentration, effects were mainly observed after 24 h of exposure, with over-transcription of cor, hsp40, rxr, and sod, whereas higher concentrations down-regulated the expression of most of the studied transcripts, especially after 48 h of exposure. In the GDC, earlier responses were observed and the fold-change magnitude was generally much higher: transcription of all target genes increased

Morphological and molecular characterization of lymnaeid snails and their potential role in transmission of Fasciola spp. in Vietnam.

Science.gov (United States)

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

2013-12-01

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

Seasonal dynamics of snail populations in coastal Kenya: Model calibration and snail control

Science.gov (United States)

Gurarie, D.; King, C. H.; Yoon, N.; Wang, X.; Alsallaq, R.

2017-10-01

A proper snail population model is important for accurately predicting Schistosoma transmission. Field data shows that the overall snail population and that of shedding snails have a strong pattern of seasonal variation. Because human hosts are infected by the cercariae released from shedding snails, the abundance of the snail population sets ultimate limits on human infection. For developing a predictive dynamic model of schistosome infection and control strategies we need realistic snail population dynamics. Here we propose two such models based on underlying environmental factors and snail population biology. The models consist of two-stage (young-adult) populations with resource-dependent reproduction, survival, maturation. The key input in the system is seasonal rainfall which creates snail habitats and resources (small vegetation). The models were tested, calibrated and validated using dataset collected in Msambweni (coastal Kenya). Seasonal rainfall in Msambweni is highly variable with intermittent wet - dry seasons. Typical snail patterns follow precipitation peaks with 2-4-month time-lag. Our models are able to reproduce such seasonal variability over extended period of time (3-year study). We applied them to explore the optimal seasonal timing for implementing snail control.

Turning snails into slugs: induced body plan changes and formation of an internal shell.

Science.gov (United States)

Osterauer, Raphaela; Marschner, Leonie; Betz, Oliver; Gerberding, Matthias; Sawasdee, Banthita; Cloetens, Peter; Haus, Nadine; Sures, Bernd; Triebskorn, Rita; Köhler, Heinz-R

2010-01-01

The archetypal body plan of conchiferan molluscs is characterized by an external calcareous shell, though internalization of shells has evolved independently in a number of molluscan clades, including gastropod families. In gastropods, the developmental process of torsion is regarded as a hallmark that is associated with a new anatomical configuration. This configuration is present in extant prosobranch gastropod species, which predominantly bear external shells. Here, we show that short-term exposure to platinum during development uncouples at least two of the processes associated with torsion of the freshwater snail Marisa cornuarietis. That is, the anus of the treated snails is located anteriorly, but the gill and the designated mantle tissue remains in a posterior location, thus preventing the formation of an external shell. In contrast to the prosobranchian archetype, platinum treatment results in the formation of a posterior gill and a cone-shaped internal shell, which persists across the lifetime. This first finding of artificially induced snail-slug conversion was also seen in the pulmonate snail Planorbarius corneus and demonstrates that selective alteration of embryonic key processes can result in fundamental changes of an existing body plan and-if altered regulation is inherited-may give rise to a new one. © 2010 Wiley Periodicals, Inc.

Snail meat: Significance and consumption

Directory of Open Access Journals (Sweden)

Dragićević Olgica

2005-01-01

Full Text Available The consumption of snail meat goes back to prehistoric times. Different ancient nations had snails on their menu, but Helices culture as a productive activity was born as a Roman culture. Some of the most economically important edible species are: Helix aspersa (Mtiller Helixpomatia (Linne, Helix iucorum (Linne, Helix aperta (Born, Eobania vermiculata (Miiller. Together with its tasie, snail meat has several advantages over others: quite low lipid rate and calorie values versus rich mineral, essential amino acid and fatty acid content. The composition of snail meat is presented. In addition, the composition of different snail species and the part analyzed (pedal mass and visceral mass is presented. Also, the differences in composition according to the species (snail meat horse/chicken meat, beef, swine meat, fish meat are presented. The French are the world's leading consumers of snails. !n France snails come to market in a variety of ways. Estimated consumption of snails in France is around 40 000 tones/year. Total French imports account for 25% of world imports. France is also the leading exporter of prepared snails, mainly sold as preserved snails and prepared dishes. Snail imports have been much higher than exports (65 tones exported in 2002. vs. 2.700 tones imported. Despite the large consumption, only 3% of snails in France come from production (farming. Italy is in second place in the world consumption of snails, and Spain and Germany are in the third and fourth place. The development of snails consumption in Italy is followed with the same amount of production of snails in the whole biological circle. In 2001, from 24,700 tons, 9,350 tons (37.8% came from production, 6 00 tons (2.4% came from nature, and 14,750 tons (59.70% came from imports (frozen, fresh and prepared snails. In Serbia, at the beginning of 2005, we had over 400 registered farms for snail production.

Ionotropic Receptors Identified within the Tentacle of the Freshwater Snail Biomphalaria glabrata, an Intermediate Host of Schistosoma mansoni.

Directory of Open Access Journals (Sweden)

Di Liang

Full Text Available Biomphalaria glabrata (B. glabrata is an air-breathing aquatic mollusc found in freshwater habitats across the Western Hemisphere. It is most well-known for its recognized capacity to act as a major intermediate host for Schistosoma mansoni, the human blood fluke parasite. Ionotropic receptors (IRs, a variant family of the ionotropic glutamate receptors (iGluR, have an evolutionary ancient function in detecting odors to initiate chemosensory signaling. In this study, we applied an array of methods towards the goal of identifying IR-like family members in B. glabrata, ultimately revealing two types, the iGluR and IR. Sequence alignment showed that three ligand-binding residues are conserved in most Biomphalaria iGluR sequences, while the IRs did exhibit a variable pattern, lacking some or all known glutamate-interactingresidues, supporting their distinct classification from the iGluRs. We show that B. glabrata contains 7 putative IRs, some of which are expressed within its chemosensory organs. To further investigate a role for the more ancient IR25a type in chemoreception, we tested its spatial distribution pattern within the snail cephalic tentacle by in situ hybridization. The presence of IR25a within presumptive sensory neurons supports a role for this receptor in olfactory processing, contributing to our understanding of the molecular pathways that are involved in Biomphalaria olfactory processing.

Impacts of an invasive snail (Tarebia granifera) on nutrient cycling in tropical streams: the role of riparian deforestation in Trinidad, West Indies.

Science.gov (United States)

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.

Effects of acute and chronic exposure to lead on the behavior of the pond snail Helisoma trivolvis

Energy Technology Data Exchange (ETDEWEB)

Bennett, V.T.; Copeland, J. [Georgia Southern Univ., Statesboro, GA (United States)

1997-09-01

The behavior of aquatic invertebrates may be useful as an indicator for the presence of toxicants in both freshwater and marine environments. The pond snail Helisoma trivolvis, the red ram`s horn, was exposed to low levels of lead (0.05 ppm). Chronic exposure significantly reduced the number of head movements but had no affect on radula movement or antenna twitches. Acute exposure resulted in curling of the foot that lasted 0.5 to 14.0 minutes. Electrochemical analysis of lead levels within treated snails indicated a higher concentration of lead in the tissue than that in the treated environment. Organ analysis of the digestive gland, 1 salivary gland, reproductive organs and the cerebral ganglion is currently being studied.

Field application of a set of cellular biomarkers in the digestive gland of the freshwater snail Radix peregra (Gastropoda, Pulmonata)

International Nuclear Information System (INIS)

Guerlet, Edwige; Ledy, Karine; Giamberini, Laure

2006-01-01

An active biomonitoring study was performed in the vicinity of two pulp and paper mill effluents (PPMEs) released in two different streams in northeastern France. Freshwater gastropods, Radix peregra (=Lymnaea peregra or Lymnaea pereger), were transplanted for 0, 3, 14 and 21 days at two to three sites located upstream and downstream from the mill discharge points in both rivers. Lysosomal and peroxisomal systems, as well as lipofuscin and neutral lipids, were tested using histochemical methods on cryostat sections of digestive gland tissues, and stereological data were obtained by image analysis. Evidence of structural changes in the lysosomal system was found in animals exposed to both effluents, comprising general stress responses such as enlarged and more numerous lysosomes; and also possible specific pluri-phasic effects. Modifications of the lysosomal and cytoplasmic contents of lipid-related materials were also described, namely enhanced lipofuscin deposit and neutral lipid depletion. The peroxisomal proliferation in exposed snails seems to show its implication in oxidative stress detoxication, without preventing higher lipoperoxidation, as indicated by the increased amounts of digestive lipofuscin. Structural changes of the lysosomal and peroxisomal systems, digestive lipofuscin and neutral lipid contents have potential for use as early cellular biomarkers in Radix peregra exposed to environmental stressors, which deserve further investigations

Modelling spatial distribution of snails transmitting parasitic worms with importance to human and animal health and analysis of distributional changes in relation to climate

DEFF Research Database (Denmark)

Pedersen, Ulrik Bo; Midzi, Nicholas; Mduluza, Takafira

2014-01-01

to naturalists but also of importance to human and animal health. The spatial distribution of freshwater snail intermediate hosts involved in the transmission of schistosomiasis, fascioliasis and paramphistomiasis (i.e. Bulinus globosus, Biomphalaria pfeifferi and Lymnaea natalensis) were modelled by the use...

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

OpenAIRE

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

2007-01-01

Previous investigations have shown that bisphenol A (BPA) induces a superfeminization syndrome in the freshwater snail Marisa cornuarietis at concentrations as low as 1 μg/L. Superfemales are characterized by the formation of additional female organs, enlarged accessory sex glands, gross malformations of the pallial oviduct, and a stimulation of egg and clutch production, resulting in increased female mortality. However, these studies were challenged on the basis of incomplete experiment...

The bioavailability of the transuranic elements 237Pu and 241Am for the pond snail, Lymnaea stagnalis L., and their behaviour in selected natural surface waters

International Nuclear Information System (INIS)

Thiels, G.M.

1983-01-01

An attempt was made to characterise the bioavailability of 237 Pu and 241 Am for the pond snail Lymnaea stagnalis L. in selected surface waters. The uptake, distribution and retention patterns were studied through the contamination route water-snail. The effects of a number of parameters, such as seasonal variation, water type (pH, conductivity, ionic composition) and presence of food, on the bioavailability of the transuranics were evaluated. Finally, an assessment was made concerning the chemical speciation of plutonium and americium in the selected freshwaters

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

Science.gov (United States)

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.

Estimating factors influencing the detection probability of semiaquatic freshwater snails using quadrat survey methods

Science.gov (United States)

Roesler, Elizabeth L.; Grabowski, Timothy B.

2018-01-01

Developing effective monitoring methods for elusive, rare, or patchily distributed species requires extra considerations, such as imperfect detection. Although detection is frequently modeled, the opportunity to assess it empirically is rare, particularly for imperiled species. We used Pecos assiminea (Assiminea pecos), an endangered semiaquatic snail, as a case study to test detection and accuracy issues surrounding quadrat searches. Quadrats (9 × 20 cm; n = 12) were placed in suitable Pecos assiminea habitat and randomly assigned a treatment, defined as the number of empty snail shells (0, 3, 6, or 9). Ten observers rotated through each quadrat, conducting 5-min visual searches for shells. The probability of detecting a shell when present was 67.4 ± 3.0%, but it decreased with the increasing litter depth and fewer number of shells present. The mean (± SE) observer accuracy was 25.5 ± 4.3%. Accuracy was positively correlated to the number of shells in the quadrat and negatively correlated to the number of times a quadrat was searched. The results indicate quadrat surveys likely underrepresent true abundance, but accurately determine the presence or absence. Understanding detection and accuracy of elusive, rare, or imperiled species improves density estimates and aids in monitoring and conservation efforts.

SHORT COMMUNICATION Challenges to increased Snail ...

African Journals Online (AJOL)

The commercial production of snails has not kept pace with the demand for it in Ibarapa Local Government Areas (ILGA) of Oyo State, Nigeria. A study was carried out to characterize the snail farmers, identify challenges to an increased snail production and suggest measures for sustainable snail production. Structured ...

MOLLUSKS IN RADIOECOLOGICAL STUDIES OF FRESHWATER ECOSYSTEMS

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Д. Гудков

2012-04-01

Full Text Available Species-specificity and dynamics of 90Sr, 137Cs and some transuraniс elements accumulation in bivalveand gastropod freshwater molluscs of the Chernobyl exclusion zone during 1998–2010 was analyzed. Theresults of radiation dose as well as chromosome aberration rate estimation and analysis of hemolymphcomposition of molluscs was produced. The radiation absorbed dose rate was registered in the range of 0.3–85.0 μGy h–1. In closed water bodies the heightened chromosome aberration rate (up to 27 % in embryotissues, and also change of haematological indexes for the adult individuals of snails was registered

Modelling spatial distribution of snails transmitting parasitic worms with importance to human and animal health and analysis of distributional changes in relation to climate

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Ulrik B. Pedersen

2014-05-01

Full Text Available The environment, the on-going global climate change and the ecology of animal species determine the localisation of habitats and the geographical distribution of the various species in nature. The aim of this study was to explore the effects of such changes on snail species not only of interest to naturalists but also of importance to human and animal health. The spatial distribution of freshwater snail intermediate hosts involved in the transmission of schistosomiasis, fascioliasis and paramphistomiasis (i.e. Bulinus globosus, Biomphalaria pfeifferi and Lymnaea natalensis were modelled by the use of a maximum entropy algorithm (Maxent. Two snail observation datasets from Zimbabwe, from 1988 and 2012, were com- pared in terms of geospatial distribution and potential distributional change over this 24-year period investigated. Climate data, from the two years were identified and used in a species distribution modelling framework to produce maps of pre- dicted suitable snail habitats. Having both climate- and snail observation data spaced 24 years in time represent a unique opportunity to evaluate biological response of snails to changes in climate variables. The study shows that snail habitat suit- ability is highly variable in Zimbabwe with foci mainly in the central Highveld but also in areas to the South and West. It is further demonstrated that the spatial distribution of suitable habitats changes with variation in the climatic conditions, and that this parallels that of the predicted climate change.

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

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Stephen W Attwood

Full Text Available 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.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.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.

Acidic, neutral and alkaline forest ponds as a landscape element affecting the biodiversity of freshwater snails.

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Spyra, Aneta

2017-08-22

In recent years, the number of areas remaining under the influence of acidity has increased. At all levels of ecosystems, biodiversity decreases with acidification, due to the elimination of species that are most sensitive to low pH. Forest ponds belong to a specific group that varied in location, a huge amount of leaf litter, and isolation from other aquatic environments. They are crucial in the industrial landscape with well-developed industry and human activity. The aim was to investigate the relative importance of water chemistry in explaining snail assemblage compositions and species richness in forest ponds of contrasting pH. Patterns in gastropod communities were determined from an analysis in 26 forest ponds with multivariate gradient analysis. Ponds ranged in a base mean pH from 3.0 to 9.0. pH has been found to be an important factor influencing gastropod fauna. Neutral ponds support diverse communities, typical of small water bodies. In two acidic pond types, snail fauna was different. Among the species characteristic for acidic ponds (pH landscape management and planning.

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

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

2013-01-01

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

Snail modulates cell metabolism in MDCK cells

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

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

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

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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.

Freshwater gastropods in the Northern littoral mesoregion of Espírito Santo, Brazil

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Marco Antônio Andrade de Souza

2017-09-01

Full Text Available Studies on the distribution of molluscs in Brazilhave been conducted since the beginning of the twentieth and the knowledge of the species distributed in the country represent important findings, which contribute to the understanding of human diseases and those of veterinary importance, transmitted by them. In order to verify the distribution of freshwater gastropods in Espírito Santo, a malacological surveywas carried out in nine municipalities that comprise the Northern mesoregion of the State, between January 2010 and February 2015. Initially the water collections occurring in the municipality were verified and the lotic systems at different levels of use and conservation were determined. Molluscs were collected monthly using a hand net adapted to a stick steel. An individual sample effort of 30 minutes was applied, by scanning, at about ten meters in each one of the selected habitats. A total of 6,000 specimens were collected, represented by genera Melanoides, Drepanotrema, Physa, Biomphalaria and Pomacea. Among the molluscs, some specimens were positive for flatworm larvae of medical and veterinary importance. The results contributed to the knowledge of the current distribution of freshwater gastropods in the Northern region of Espírito Santo whose the only record for the region dates back to 1983.

Snail1 Expression Is Required for Sarcomagenesis

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Lorena Alba-Castellón

2014-05-01

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

Development of Helisoma trivolvis pond snails as biological samplers for biomonitoring of current-use pesticides.

Science.gov (United States)

Morrison, Shane A; Belden, Jason B

2016-09-01

Nontarget aquatic organisms residing in wetlands are commonly exposed to current-use pesticides through spray drift and runoff. However, it is frequently challenging to measure exposure because of rapid dissipation of pesticides from water and reduced bioavailability. The authors' hypothesis is that freshwater snails can serve as bioindicators of pesticide exposure based on their capacity to passively accumulate tissue residues. Helisoma trivolvis snails were evaluated as biomonitors of pesticide exposure using a fungicide formulation that contains pyraclostrobin and metconazole and is frequently applied to crops surrounding depressional wetlands. Exposure-response studies indicate that H. trivolvis are tolerant of pyraclostrobin and metconazole at concentrations >10 times those lethal to many aquatic species, with a median lethal concentration based on pyraclostrobin of 441 μg/L (95% confidence interval of 359-555 μg/L). Bioconcentration factors ranged from 137 mL/g to 211 mL/g and from 39 mL/g to 59 mL/g for pyraclostrobin and metconazole, respectively. Elimination studies suggested one-compartmental elimination and snail tissue half-lives (t50 ) of approximately 15 h and 5 h for pyraclostrobin and metconazole, respectively. Modeling derived toxicokinetic parameters in the context of an environmentally relevant pulsed exposure suggests that residues can be measured in snails long after water concentrations fall below detection limits. With high fungicide tolerance, rapid accumulation, and slow elimination, H. trivolvis may be viable for biomonitoring of pyraclostrobin and should be investigated for other pesticides. Environ Toxicol Chem 2016;35:2320-2329. © 2016 SETAC. © 2016 SETAC.

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

Science.gov (United States)

Pointier, J P

1993-06-01

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

The Classroom Animal: Snails.

Science.gov (United States)

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)

Energetic endpoints provide early indicators of life history effects in a freshwater gastropod exposed to the fungicide, pyraclostrobin

International Nuclear Information System (INIS)

Fidder, Bridgette N.; Reátegui-Zirena, Evelyn G.; Olson, Adric D.; Salice, Christopher J.

2016-01-01

Organismal energetics provide important insights into the effects of environmental toxicants. We aimed to determine the effects of pyraclostrobin on Lymnaea stagnalis by examining energy allocation patterns and life history traits. Juvenile snails exposed to pyraclostrobin decreased feeding rate and increased apparent avoidance behaviors at environmentally relevant concentrations. In adults, we found that sublethal concentrations of pyraclostrobin did not affect reproductive output, however, there were significant effects on developmental endpoints with longer time to hatch and decreased hatching success in pyraclostrobin-exposed egg masses. Further, there were apparent differences in developmental effects depending on whether mothers were also exposed to pyraclostrobin suggesting this chemical can exert intergenerational effects. Pyraclostrobin also affected protein and carbohydrate content of eggs in mothers that were exposed to pyraclostrobin. Significant effects on macronutrient content of eggs occurred at lower concentrations than effects on gross endpoints such as hatching success and time to hatch suggesting potential value for these endpoints as early indicators of ecologically relevant stress. These results provide important insight into the effects of a common fungicide on important endpoints for organismal energetics and life history. - Highlights: • We exposed a freshwater snail to relevant concentrations of pyraclostrobin. • We monitored energetic and life history endpoints. • Pyraclostrobin affected feeding, hatching success and egg macronutrient content. • Energetic-based endpoints may provide valuable insight to toxic effects. - The fungicide pyraclostrobin at environmentally relevant concentrations effects a range of life history and energetic endpoints in the freshwater snail, Lymnaea stagnalis.

Acidic, neutral and alkaline forest ponds as a landscape element affecting the biodiversity of freshwater snails

Science.gov (United States)

Spyra, Aneta

2017-10-01

In recent years, the number of areas remaining under the influence of acidity has increased. At all levels of ecosystems, biodiversity decreases with acidification, due to the elimination of species that are most sensitive to low pH. Forest ponds belong to a specific group that varied in location, a huge amount of leaf litter, and isolation from other aquatic environments. They are crucial in the industrial landscape with well-developed industry and human activity. The aim was to investigate the relative importance of water chemistry in explaining snail assemblage compositions and species richness in forest ponds of contrasting pH. Patterns in gastropod communities were determined from an analysis in 26 forest ponds with multivariate gradient analysis. Ponds ranged in a base mean pH from 3.0 to 9.0. pH has been found to be an important factor influencing gastropod fauna. Neutral ponds support diverse communities, typical of small water bodies. In two acidic pond types, snail fauna was different. Among the species characteristic for acidic ponds (pH aquatic ecosystems is still incomplete because anthropogenic acidification is a recent phenomenon. It is extremely important in forest habitats, since they react more intensively to climatic factors and are often used in landscape management and planning.

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

Science.gov (United States)

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

2000-12-01

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

Variation of snail's abundance in two water bodies harboring strains of Pseudosuccinea columella resistant and susceptible to Fasciola hepatica miracidial infection, in Pinar del Río Province, Cuba

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Alfredo Gutiérrez

2005-11-01

Full Text Available The abundance of freshwater snails in two rural sites of Pinar del Río, Cuba, which harbor Pseudosuccinea columella susceptible and resistant to miracidia of Fasciola hepatica was followed for one year. Susceptible snails were found in the most anthropic site (IPA whereas the resistant population inhabited the most preserved one (El Azufre. Only two snail species coexisted with P. columella at IPA site (Physa cubensis and Tarebia granifera while five species were found at El Azufre, including an endemic from that province (Hemisinus cubanianus. Populations of both resistant and susceptible snails showed stable densities throughout the year, although the susceptible strain attained higher abundance. The highest densities were observed in April-May 2004 for the susceptible population whereas the resistant strain attained its highest abundance in January 2004. No record of Fossaria cubensis was made and the thiarid T. granifera occurred only at low densities. One of the sampled sites (IPA meets all the conditions for the first report of P. columella naturally infected with larvae of F. hepatica.

Variation of snail's abundance in two water bodies harboring strains of Pseudosuccinea columella resistant and susceptible to Fasciola hepatica miracidial infection, in Pinar del Río Province, Cuba.

Science.gov (United States)

Gutiérrez, Alfredo; Hernandez, Dagmar F; Sánchez, Jorge

2005-11-01

The abundance of freshwater snails in two rural sites of Pinar del Río, Cuba, which harbor Pseudosuccinea columella susceptible and resistant to miracidia of Fasciola hepatica was followed for one year. Susceptible snails were found in the most anthropic site (IPA) whereas the resistant population inhabited the most preserved one (El Azufre). Only two snail species coexisted with P. columella at IPA site (Physa cubensis and Tarebia granifera) while five species were found at El Azufre, including an endemic from that province (Hemisinus cubanianus). Populations of both resistant and susceptible snails showed stable densities throughout the year, although the susceptible strain attained higher abundance. The highest densities were observed in April-May 2004 for the susceptible population whereas the resistant strain attained its highest abundance in January 2004. No record of Fossaria cubensis was made and the thiarid T. granifera occurred only at low densities. One of the sampled sites (IPA) meets all the conditions for the first report of P. columella naturally infected with larvae of F. hepatica.

Prognostic significance of snail expression in hilar cholangiocarcinoma

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Kong, Dalu [Department of Hepatobiliary Surgery, Tianjin Medical University Cancer Institute and Hospital, Hexi District, Tianjin (China); Liang, Jun [Department of Oncology, Affiliated Hospital of Medical College, Qingdao University, Qingdao, Shandong Province (China); Li, Rong [Department of Hepatobiliary Surgery, Tianjin Medical University Cancer Institute and Hospital, Hexi District, Tianjin (China); Liu, Shihai [Department of Laboratory Center, Affiliated Hospital of Medical College, Qingdao University, Qingdao, Shandong Province (China); Wang, Jigang [Department of Oncology, Affiliated Hospital of Medical College, Qingdao University, Qingdao, Shandong Province (China); Zhang, Kejun; Chen, Dong [Department of General Surgery, Affiliated Hospital of Medical College, Qingdao University, Qingdao, Shandong Province (China)

2012-05-11

Many patients with hilar cholangiocarcinoma (HC) have a poor prognosis. Snail, a transcription factor and E-cadherin repressor, is a novel prognostic factor in many cancers. The aim of this study was to evaluate the relationship between snail and E-cadherin protein expression and the prognostic significance of snail expression in HC. We examined the protein expression of snail and E-cadherin in HC tissues from 47 patients (22 males and 25 females, mean age 61.2 years) using immunohistochemistry and RT-PCR. Proliferation rate was also evaluated in the same cases by the MIB1 index. High, low and negative snail protein expression was recorded in 18 (38%), 17 (36%), and 12 (26%) cases, respectively, and 40.4% (19/47) cases showed reduced E-cadherin protein expression in HC samples. No significant correlation was found between snail and E-cadherin protein expression levels (P = 0.056). No significant correlation was found between snail protein expression levels and gender, age, tumor grade, vascular or perineural invasion, nodal metastasis and invasion, or proliferative index. Cancer samples with positive snail protein expression were associated with poor survival compared with the negative expresser groups. Kaplan-Meier curves comparing different snail protein expression levels to survival showed highly significant separation (P < 0.0001, log-rank test). With multivariate analysis, only snail protein expression among all parameters was found to influence survival (P = 0.0003). We suggest that snail expression levels can predict poor survival regardless of pathological features and tumor proliferation. Immunohistochemical detection of snail protein expression levels in routine sections may provide the first biological prognostic marker.

Human parasitic meningitis caused by Angiostrongylus cantonensis infection in Taiwan.

Science.gov (United States)

Tsai, Hung-Chin; Chen, Yao-Shen; Yen, Chuan-Min

2013-06-01

The major cause of eosinophilic meningitis in Taiwan is Angiostrongylus cantonensis. Humans are infected by ingesting terrestrial and freshwater snails and slugs. In 1998 and 1999, two outbreaks of eosinophilic meningitis caused by A. cantonensis infection were reported among 17 adult male immigrant Thai laborers who had eaten raw golden apple snails (Pomacea canaliculata). Another outbreak associated with consuming a health drink consisting of raw vegetable juice was reported in 2001. These adult cases differed from reports in the 1970s and 1980s, in which most of the cases were in children. With improvements in public health and education of foreign laborers, there have since been only sporadic cases in Taiwan. Review of clinical research indicates inconsistent association of Magnetic Resonance Imaging (MRI) results with clinical features of eosinophilic meningitis. MRI features were nonspecific but there was an association between the presence of high brain MRI signal intensities and severity of peripheral and cerebrospinal fluid (CSF) eosinophilia. Inflammatory markers have been identified in the CSF of patients with eosinophilic meningitis caused by A. cantonensis infection, and vascular endothelial growth factor (VEGF), hepatocyte growth factor (HGF), and the matrix metalloproteinase system may be associated with blood-brain barrier disruption. Eosinophilic meningitis caused by A. cantonensis infection is not a reportable disease in Taiwan. It is important that a public advisory and education program be developed to reduce future accidental infection.

Modeling snail breeding in Bioregenerative Life Support System

Science.gov (United States)

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

Eosinophilic meningitis risk associated with raw Ampullarium canaliculatus snails consumption

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Jiun-Jye Wang

2011-05-01

Full Text Available 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.

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

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Maria Kokkinopoulou

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

Modeling snail breeding in a bioregenerative life support system

Science.gov (United States)

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.

Snail arboreality: the microdistribution of Sitalajenyn.si (Gastropoda ...

African Journals Online (AJOL)

G = the number or snails in grasses, % = percentage proportion of shruh snail s to the total number ot' snails in both habitats, ..... transmission pylons (P.F. Kasigwa personal observations). .... ation and k is any positive integer. References.

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

International Nuclear Information System (INIS)

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

1981-01-01

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

Parasites of edible land snails in Edo State, Nigeria

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Igbinosa I. B.

2016-12-01

Full Text Available Land snails are sources of protein to man and are hosts to a number of parasites. It is imperative that the roles of the snail hosts and parasites are clearly defined. Before then however, the parasites of the different land snails collected in any locality should be identified. Land snails were collected in the wild in both dry and wet seasons. The internal organs and the faeces were examined for the presence of parasite. In the rainy season of 2015, a total of 272 snails were collected across four major towns (Benin, Uromi, Ekpoma and Auchi in Edo State, Nigeria, while in the dry season, fewer snails (n=91 were handpicked. The snail species seen are: Achatina achatina (Linnaeus, 1758, Achatina fulica (Férussac, 1821, Acharchatina marginata (Swainson, 1982, Limicolaria aurora (Jay, 1839, L. flammea (Müller, 1774 and Limicolariopsis spp. The larvae of Strongyloides stercoralis were isolated from the various snail species with overall prevalence of 54.04 %. Snails positive with Alaria mesocercariae were L. aurora, L. flammea and Limicolariopsis spp. Additionally, few L. flammea were positive of the cercariae of Drocoelium dedriticum. Meanwhile, some samples of A. fulica harboured larvae of Angiostrongylus cantonesis, sporocysts of Fasciola gigantica and Schistosoma mansoni. Therefore, these edible snails could pose serious health hazard to man and animals by serving as a possible alternative parasite transmission route.

Toxicidade aguda do sulfato de cobre e do extrato aquoso de folhas secas de nim para o caramujo (Pomacea canaliculata = Acute toxicity of copper sulfate and aqueous extract of dried neem leaves on snails (Pomacea canaliculata

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Francine Perri Venturini

2008-04-01

Full Text Available Os caramujos podem se tornar um problema ambiental e econômico, podendo causar muitos prejuízos. O trabalho teve como objetivo estimar a toxicidade aguda do sulfato de cobre pentaidratado (CuSO4.5H2O e do extrato aquoso de folhas secas de nim para o P. canaliculata, em condição de laboratório. Para determinação da CL (I(50;96h, o caramujo foi exposto a seis concentrações crescentes de sulfato de cobre (0,0; 0,01; 0,03; 0,05; 0,07 e 0,1 mg L-1 e a seis concentrações crescentes de extrato aquoso de folhas secas denim (0,0; 100; 125; 150; 175 e 200 mL de extrato aquoso de folhas secas de nim L-1 de água, equivalente a 0,0; 1,18; 1,47; 1,77; 2,06; e 2,36 mg de azadiractina L-1, com três repetições e um tratamento-controle em um experimento no delineamento inteiramente casualizado(DIC. A CL (I(50;96h estimada para o caramujo foi de 0,07 mg de sulfato de cobre L-1, com limite inferior de 0,05 mg L-1 e limite superior de 0,1 mg L-1. A concentração letal 50% (CL (I50;96h estimada do extrato aquoso de folhas secas de nim (EAFSN para o caramujo foi de 142,75 mL L-1, equivalente a 1,68 mg L-1 de azadiractina, com limite inferior de 130,89 mL L-1 (1,54, mg L-1 e limite superior de 155,69 mL L-1 (1,83 mg L-1.Snails can become an environmental and economic problem, causing substantial losses. The objective of this work was to estimatethe acute toxicity of copper sulfate pentahydrate (CuSO4.5H2O and the aqueous extract of dried neem leaves on snails (P. canaliculata under laboratory conditions. In order to estimate the lethal concentration 50% (LC (I50;96h, snails were exposed to six increasing copper sulfate concentrations (0.0; 0.01; 0.03; 0.05; 0.07 and 0.1 mg L-1 and six increasing concentrations of aqueous extract of dried neem leaves 0.0; 100; 125; 150; 175 and 200 mL aqueous extract of dried neem leaves L-1 water, equivalent to (0.0; 1.18; 1.47; 1.77; 2.06; and 2.36 mg azadirachtin L-1, in triplicate and one control treatment in an

Inheritance of Schistosoma mansoni infection incompatibility in Biomphalaria alexandrina snails

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Iman F Abou El Naga

2010-03-01

Full Text Available In this study, we looked at the inheritance of susceptibility and resistance to Schistosoma mansoni infection in the first generation of crossbred Biomphalaria alexandrina snails. Our ultimate goal is to use such information to develop a biological method of controlling schistosomiasis. We infected laboratory-bred snails with S. mansoni miracidia and examined cercarial shedding to determine susceptibility and resistance. Five parental groups were used: Group I contained 30 susceptible snails, Group II contained 30 resistant snails, Group III contained 15 susceptible and 15 resistant snails, Group IV contained 27 susceptible and three resistant snails and Group V contained three susceptible and 27 resistant snails. The percentage of resistant snails in the resulting progeny varied according to the ratio of susceptible and resistant parents per group; they are 7%, 100%, 68%, 45% and 97% from Groups I, II, III, IV and V, respectively. On increasing the percentage of resistant parent snails, the percentage of resistant progeny increased, while cercarial production in their susceptible progeny decreased.

Land Snail Extinctions at Kalaeloa, O`ahu

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T.S. Dye

2001-06-01

Full Text Available In this article we show that the interpretation of Polynesian influence drawn from the stratigraphic record of sub-fossil land snails at Kalaeloa (O'ahu, Hawai'i is based on a unique stratigraphic sequence at a single sinkhole. The interpretation was then applied to other land snail sequences, despite their lack of evidence for Polynesian influence. We present a reanalysis of the stratigraphic record to conclude that Polynesians had little, if any, effect on land snail populations in sinkholes. We show that directional change in land snail populations was underway before Polynesians colonised the islands. Decreases in the diversity of snail populations, possibly indicative of environmental stress, do occur near the end of the stratigraphic sequence. Based on available dating evidence, however, these changes probably took place in the post-Contact period when the regional environment was radically altered by sugar cane cultivation.

Possible competitive displacement of planorbids by Melanoides tuberculata in Minas Gerais, Brazil

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Carlos Tito Guimarães

2001-09-01

Full Text Available Several species of snails, including Pomacea haustrum, Marisa cornuarietis and Helisoma duryi, have been identified as probable competitors and/or predators of planorbid intermediate hosts of Schistosoma. During the last few years, studies carried out in the Caribbean region have shown reductions and even disappearances of populations of Biomphalaria glabrata and B. straminea in breeding places where the snail Melanoides tuberculata was introduced. Observations made over a period of 10 years in two lakes close to Belo Horizonte, MG, showed that there were marked reductions in autochthonous populations of B. glabrata and B. straminea after the arrival of M. tuberculata, both Biomphalaria species disappearing completely after eight years.

Possible competitive displacement of planorbids by Melanoides tuberculata in Minas Gerais, Brazil.

Science.gov (United States)

Guimarães, C T; Souza, C P; Soares Dd

2001-01-01

Several species of snails, including Pomacea haustrum, Marisa cornuarietis and Helisoma duryi, have been identified as probable competitors and/or predators of planorbid intermediate hosts of Schistosoma. During the last few years, studies carried out in the Caribbean region have shown reductions and even disappearances of populations of Biomphalaria glabrata and B. straminea in breeding places where the snail Melanoides tuberculata was introduced. Observations made over a period of 10 years in two lakes close to Belo Horizonte, MG, showed that there were marked reductions in autochthonous populations of B. glabrata and B. straminea after the arrival of M. tuberculata, both Biomphalaria species disappearing completely after eight years.

Lichen Endozoochory by Snails

Science.gov (United States)

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

2011-01-01

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

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

Science.gov (United States)

Suski, Jamie G.; Salice, Christopher J.; Patino, Reynaldo

2012-01-01

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

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

Science.gov (United States)

Wahl, Martin

2008-05-01

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

Miracidial infectivity of snail host ( Bulinus truncatus ) in the laboratory

African Journals Online (AJOL)

Miracidial infectivity rate of snail Bulinus truncatus collected from Agulu Lake was studied in the laboratory. The snails were maintained in the laboratory and eggs deposited were allowed to hatch and dates noted until snails of different ages were produced. These snails were consequently exposed to miracidia hatched ...

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

DEFF Research Database (Denmark)

Madsen, Henry; Coulibaly, Godefroy; Furu, Peter

1987-01-01

densities appeared to be associated with human water contact activities, which apparently create favourable biotopes for the snails. This is probably due to an alteration of the vegetation and an increase of the trophic status of the site by contamination with food remnants and other debris. The larger...

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

Science.gov (United States)

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

2011-01-01

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

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

International Nuclear Information System (INIS)

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

2012-01-01

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

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

Energy Technology Data Exchange (ETDEWEB)

Vincent-Hubert, Francoise, E-mail: francoise.vincent-hubert@irstea.fr [Unite de Recherche Hydrosystemes et Bioprocedes, equipe BELCA, IRSTEA/CEMAGREF, 1 rue Pierre-Gilles de Gennes, CS10030, 92761 Antony cedex, 92163 Antony (France); Revel, Messika [Unite de Recherche Hydrosystemes et Bioprocedes, equipe BELCA, IRSTEA/CEMAGREF, 1 rue Pierre-Gilles de Gennes, CS10030, 92761 Antony cedex, 92163 Antony (France); Garric, Jeanne [MALY Laboratoire d' ecotoxicologie, IRSTEA/CEMAGREF, 23 bis Quai Chauveau, 69006 Lyon (France)

2012-10-15

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

Salinity and temperature tolerance of the invasive freshwater gastropod Tarebia granifera

Directory of Open Access Journals (Sweden)

Renzo Perissinotto

2010-04-01

Full Text Available Invasive aquatic species, such as the gastropod Tarebia granifera, can cause ecological isturbances and potentially reduce biodiversity by displacing indigenous invertebrates. In South Africa, T. granifera was first recorded in an estuarine environment in the St Lucia Estuary. Its tolerance to salinity and temperature was investigated through the experimental manipulation of these factors. T. granifera can tolerate temperatures between 0 ºC and 47.5 ºC, allowing it to survive high temperature extremes. The species may also survive cold snaps and invade higher altitude areas. More remarkably, this snail survives high salinity for a relatively long time, as LS₅₀ (lethal salinity for 50% of the population was reached at 30 psu over 65–75 days. However, higher salinity adversely affected the T. granifera population. Snails acclimated to freshwater conditions and suddenly transferred to 30 psu experienced 100% mortality within 48 h. Snail activity also declined with increasing salinity. T. granifera’s environmental tolerance and parthenogenetic characteristics are the keys to successful introduction and establishment. Therefore, the management of T. granifera may prove diffcult in the short to medium term. The present findings constitute a contribution to the knowledge of biological invasions in Africa and to the understanding of estuarine invasions by T. granifera.

Microbiological quality of raw and processed wild and cultured edible snails.

Science.gov (United States)

Parlapani, Foteini F; Neofitou, Christos; Boziaris, Ioannis S

2014-03-15

An increasing interest in snail farming in Greece and other European countries has been observed. Despite the fact that edible snails have been involved with problems of Salmonella spp. contamination, there are to our knowledge only limited studies regarding microbiological safety and hygiene of such products. Enumeration of microbial populations and presence/absence of Salmonella spp. in snail meat and intestines of wild Cornu aspersum, Helix lucorum and cultured Cornu aspersum snails from indoor/outdoor type farms was conducted. Furthermore, snail-processing steps were simulated in the laboratory and the population reduction in snail meat was determined. Microbial populations were higher in intestines than snail meat in almost all cases. Escherichia coli/coliforms and Enterococcus spp. populations were lower in the intestines and snail meat of cultured C. aspersum. Salmonella spp. were detected in the intestines and snail meat of wild snails only. The high levels of bacterial populations were considerably reduced after the appropriate processing. The lower populations of E. coli/coliforms, Enterococcus spp. and especially the absence of Salmonella spp. in cultured snails show that the controlled conditions decrease the possibility of pathogen presence and contribute to food safety and public health. © 2013 Society of Chemical Industry.

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

International Nuclear Information System (INIS)

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

2014-01-01

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

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

KAUST Repository

Sun, Jin; Mu, Huawei; Zhang, Huoming; Chandramouli, Kondethimmanahalli H.; Qian, Peiyuan; Wong, Christina; Qiu, Jianwen

2013-01-01

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

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

Science.gov (United States)

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

2015-01-01

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

Degree of Acetylization Chitosan Gonggong Snail Shells

Science.gov (United States)

Horiza, H.; Iskandar, I.; Aldo, N.

2018-04-01

Chitosan is a polysaccharide obtained from the deacetylation of chitin, which is generally derived from crustacean animal waste and animal skins other sea. One marine animals that have compounds that can be processed chitin chitosan is derived from the snail Gonggong marine waters of Riau Islands province. The purpose of this study was to determine the degree of chitosan from the shells of snails asetilisasi Gonggong. This research is an experimental research laboratory. The results of this study indicate that the degree of chitosan shell snail deasetilisasi Gonggong is 70.27%.

Profitability of Snail Production in Osun State,Nigeria | Baba ...

African Journals Online (AJOL)

The study determined the features and profitability of snail farming in Osun State. To achieve the study objectives, 20 snail farmers each were randomly selected from Osogbo, Iwo and Ife-Ijesa townships, where majority of snail farmers in the State were located. Data collected from the farmers were analysed using ...

CYTOGENETIC STUDY OF FOUR SPECIES OF LAND SNAILS OF ...

African Journals Online (AJOL)

The chromosomal study of the four species of achatinid snails was carried out with the aim of determining their chromosome numbers as part of a preliminary attempt to understand the cytogenetics of land snails of Nigeria. The haploid chromosomes of various species of snails studied were obtained from their ovotestis ...

Desarrollo morfológico e histológico del sistema reproductor de Pomacea patula catemacensis (Baker 1922) (Mollusca, Caenogastropoda: Ampullariidae) Morphological and histological development of the reproductive system of Pomacea patula catemacensis (Baker 1922) (Mollusca, Caenogastropoda: Ampullariidae)

OpenAIRE

AURA CARREÓN-PALAU; ESTHER URIA-GALICIA; FÉLIX ESPINOSA-CHÁVEZ; FERNANDO MARTÍNEZ-JERÓNIMO

2003-01-01

El "tegogolo" Pomacea patula catemacensis es un gasterópodo dulceacuícola comestible, endémico del Lago de Catemaco en Veracruz, México. En los últimos años las poblaciones naturales se han visto diezmadas debido a que su captura se realiza sin control, a lo que se suma el alto grado de deterioro ambiental que presenta el lago, producto del "azolvamiento", así como por la contaminación por plaguicidas y detergentes. El objetivo del presente estudio fue caracterizar histológica y morfológicame...

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

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Edward P Levri

Full Text Available 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.

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

Science.gov (United States)

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.

Moluscos dulceacuícolas exóticos en Chile Exotic freshwater mollusks in Chile

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Sergio Letelier V.

2007-10-01

Full Text Available Las especies de moluscos exóticas dulceacuícolas registradas en esta contribución, corresponden a ejemplares recolectados en humedales en acuarios comerciales o interceptados en barreras aduaneras, así como de referencias bibliográficas. Un total de 7 especies pertenecientes a 6 géneros fueron identificadas: Pomacea bridgesii; Helobia sp.; Thiara (Melanoides tuberculata; Melanoides maculata; Physa sp.; Physella venustula y Biomphalaria sp. Melanoides maculata fue recolectada en el río Lluta y clasificada como especie criptogénica. Los moluscos exóticos recolectados podrían tener éxito en su establecimiento si se considera la vulnerabilidad de los hábitats nativos debido al cambio en las condiciones climáticas globales o a las elevaciones térmicas producidas en el sector costero por los fenómenos de El Niño. En este sentido, las especies subtropicales observadas se podrían considerar como no endémicas y vectores potenciales de zoonosis parasitarias. Las principales vías de introducción de moluscos dulceacuícolas exóticos se derivaron del intercambio comercial, por lo cual, y frente a su incremento interregional, se hace necesario recopilar datos ecológicos y taxonómicos adecuados que permitan evaluar el riesgo de su establecimiento, así como servir de base para la aplicación de futuros tratamientos en bioseguridad.The exotic freshwater mollusk species we report here were collected in wetlands, commercial aquariums, or were given to us by government officials who intercepted some exotic species at customs offices. Other records came from the specialized literature. These species are Pomacea bridgesii; Helobia sp.; Thiara (Melanoides tuberculata; Melanoides maculata; Physa sp., Physella venustula and Biomphalaria sp. It is not clear how Melanoides maculata, found in the Río Lluta, reached Chile. The exotic species collected could expand their ranges in Chilean territory given global environmental and climate change or the

Venomics-Accelerated Cone Snail Venom Peptide Discovery

Science.gov (United States)

Himaya, S. W. A.

2018-01-01

Cone snail venoms are considered a treasure trove of bioactive peptides. Despite over 800 species of cone snails being known, each producing over 1000 venom peptides, only about 150 unique venom peptides are structurally and functionally characterized. To overcome the limitations of the traditional low-throughput bio-discovery approaches, multi-omics systems approaches have been introduced to accelerate venom peptide discovery and characterisation. This “venomic” approach is starting to unravel the full complexity of cone snail venoms and to provide new insights into their biology and evolution. The main challenge for venomics is the effective integration of transcriptomics, proteomics, and pharmacological data and the efficient analysis of big datasets. Novel database search tools and visualisation techniques are now being introduced that facilitate data exploration, with ongoing advances in related omics fields being expected to further enhance venomics studies. Despite these challenges and future opportunities, cone snail venomics has already exponentially expanded the number of novel venom peptide sequences identified from the species investigated, although most novel conotoxins remain to be pharmacologically characterised. Therefore, efficient high-throughput peptide production systems and/or banks of miniaturized discovery assays are required to overcome this bottleneck and thus enhance cone snail venom bioprospecting and accelerate the identification of novel drug leads. PMID:29522462

Venomics-Accelerated Cone Snail Venom Peptide Discovery

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S. W. A. Himaya

2018-03-01

Full Text Available Cone snail venoms are considered a treasure trove of bioactive peptides. Despite over 800 species of cone snails being known, each producing over 1000 venom peptides, only about 150 unique venom peptides are structurally and functionally characterized. To overcome the limitations of the traditional low-throughput bio-discovery approaches, multi-omics systems approaches have been introduced to accelerate venom peptide discovery and characterisation. This “venomic” approach is starting to unravel the full complexity of cone snail venoms and to provide new insights into their biology and evolution. The main challenge for venomics is the effective integration of transcriptomics, proteomics, and pharmacological data and the efficient analysis of big datasets. Novel database search tools and visualisation techniques are now being introduced that facilitate data exploration, with ongoing advances in related omics fields being expected to further enhance venomics studies. Despite these challenges and future opportunities, cone snail venomics has already exponentially expanded the number of novel venom peptide sequences identified from the species investigated, although most novel conotoxins remain to be pharmacologically characterised. Therefore, efficient high-throughput peptide production systems and/or banks of miniaturized discovery assays are required to overcome this bottleneck and thus enhance cone snail venom bioprospecting and accelerate the identification of novel drug leads.

Bisphenol A Induces Superfeminization in the Ramshorn Snail (Gastropoda: Prosobranchia) at Environmentally Relevant Concentrations

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

2006-01-01

Previous investigations have shown that bisphenol A (BPA) induces a superfeminization syndrome in the freshwater snail Marisa cornuarietis at concentrations as low as 1 μg/L. Superfemales are characterized by the formation of additional female organs, enlarged accessory sex glands, gross malformations of the pallial oviduct, and a stimulation of egg and clutch production, resulting in increased female mortality. However, these studies were challenged on the basis of incomplete experimentation. Therefore, the objective of the current approach was to bridge several gaps in knowledge by conducting additional experiments. In an initial series of experiments, study results from the reproductive phase of the snails were evaluated in the sub-micrograms per liter range. Before and after the spawning season, superfemale responses were observed [NOEC (no observed effect concentration) 7.9 ng/L, EC10 (effective concentration at 10%) 13.9 ng/L], which were absent during the spawning season. A further experiment investigated the temperature dependence of BPA responses by exposing snails at two temperatures in parallel. The adverse effect of BPA was at least partially masked at 27°C (EC10 998 ng/L) when compared with 20°C (EC10 14.8 ng/L). In M. cornuarietis, BPA acts as an estrogen receptor (ER) agonist, because effects were completely antagonized by a co-exposure to tamoxifen and Faslodex. Antiandrogenic effects of BPA, such as a significant decrease in penis length at 20°C, were also observed. Competitive receptor displacement experiments indicate the presence of androgen- and estrogen-specific binding sites. The affinity for BPA of the estrogen binding sites in M. cornuarietis is higher than that of the ER in aquatic vertebrates. The results emphasize that prosobranchs are affected by BPA at lower concentrations than are other wildlife groups, and the findings also highlight the importance of exposure conditions. PMID:16818258

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

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EC Oliveira-Filho

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

Reproductive ecology of the giant African snail in South Florida

DEFF Research Database (Denmark)

Roda, Amy; Nachman, Gøsta Støger; Weihman, Scott

2016-01-01

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......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...

Determinants of production level of commercial snail farmers in Oyo ...

African Journals Online (AJOL)

The study investigates the determinants of productivity level among commercial snail farmers in Oyo State. A systematic sampling technique was employed to select one-hundred and forty–two snail farmers from the membership list provided by the Snail Farmers Association of Nigeria (SFAN), Oyo State Chapter.

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

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Bruno Bonnemain

2005-01-01

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

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

Energy Technology Data Exchange (ETDEWEB)

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

2013-12-10

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

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

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Amy Roda

Full Text Available 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 (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.

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

Science.gov (United States)

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 (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

A survey of snail farms in Cross River State, Nigeria | Ogogo | Global ...

African Journals Online (AJOL)

The existence of snail in the wild has become threatened, and information on the efficiency and effectiveness of ex - situ management of snails in many areas is urgently needed for consistent supply of snails. This work, therefore surveyed the practice and adoption of snail farming technology in Cross River State, Nigeria.

Relationship between snail population density and infection status of snails and fish with zoonotic trematodes in Vietnamese carp nurseries

DEFF Research Database (Denmark)

Clausen, Jesper Hedegaard; Madsen, Henry; Murrell, Kenneth Darwin

2012-01-01

ponds. Previous risk assessment on FZT transmission in the Red River Delta of Vietnam identified carp nursery ponds as major sites of transmission. In this study, we analyzed the association between snail population density and heterophyid trematode infection in snails with the rate of FZT transmission...... to juvenile fish raised in carp nurseries....

Evaluation of the toxic effect of endocrine disruptor Bisphenol A (BPA) in the acute and chronic toxicity tests with Pomacea lineata gastropod.

Science.gov (United States)

de Andrade, André Lucas Correa; Soares, Priscila Rafaela Leão; da Silva, Stephannie Caroline Barros Lucas; da Silva, Marília Cordeiro Galvão; Santos, Thamiris Pinheiro; Cadena, Marilia Ribeiro Sales; Soares, Pierre Castro; Cadena, Pabyton Gonçalves

2017-07-01

Bisphenol A (BPA) is a plasticizer and a risk when it interacts with organisms, and can cause changes in the development and reproduction of them. This study aimed to evaluate the effects of BPA, by acute and chronic toxicity tests with neonates and adults of Pomacea lineata. Adults and neonates were divided into groups exposed to BPA (1-20mg/L), or 17β-estradiol (1mg/L) and control in the acute and chronic toxicity tests. Behavior, heart rate, reproduction and hemolymph biochemical analysis were measured. In the acute toxicity test, the 96-h LC 50 with adults was 11.09 and with neonates was 3.14mg/L. In this test, it was observed lethargic behavior and an increase of 77.6% of aspartate aminotransferase in the adults' hemolymph (ptest, it was observed behaviors associated with reproduction, as Copulate, in the groups exposed to BPA. The results that were found in this study proved that BPA is a potentially toxic agent to Pomacea lineata according to biological parameters evaluated. These data contribute to the understanding of BPA toxic effects' in the aquatic invertebrates. Copyright © 2017 Elsevier Inc. All rights reserved.

Modelling the spatial and seasonal distribution of suitable habitats of schistosomiasis intermediate host snails using Maxent in Ndumo area, KwaZulu-Natal Province, South Africa

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Tawanda Manyangadze

2016-11-01

Full Text Available Abstract Background Schistosomiasis is a snail-borne disease endemic in sub-Saharan Africa transmitted by freshwater snails. The distribution of schistosomiasis coincides with that of the intermediate hosts as determined by climatic and environmental factors. The aim of this paper was to model the spatial and seasonal distribution of suitable habitats for Bulinus globosus and Biomphalaria pfeifferi snail species (intermediate hosts for Schistosoma haematobium and Schistosoma mansoni, respectively in the Ndumo area of uMkhanyakude district, South Africa. Methods Maximum Entropy (Maxent modelling technique was used to predict the distribution of suitable habitats for B. globosus and B. pfeifferi using presence-only datasets with ≥ 5 and ≤ 12 sampling points in different seasons. Precipitation, maximum and minimum temperatures, Normalised Difference Vegetation Index (NDVI, Normalised Difference Water Index (NDWI, pH, slope and Enhanced Vegetation Index (EVI were the background variables in the Maxent models. The models were validated using the area under the curve (AUC and omission rate. Results The predicted suitable habitats for intermediate snail hosts varied with seasons. The AUC for models in all seasons ranged from 0.71 to 1 and the prediction rates were between 0.8 and 0.9. Although B. globosus was found at more localities in the Ndumo area, there was also evidence of cohabiting with B. pfiefferi at some of the locations. NDWI had significant contribution to the models in all seasons. Conclusion The Maxent model is robust in snail habitat suitability modelling even with small dataset of presence-only sampling sites. Application of the methods and design used in this study may be useful in developing a control and management programme for schistosomiasis in the Ndumo area.

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

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Yousif, F; Lämmler, G

1975-10-16

Sixteen species of aquatic snails of four families were tested by quantitative technique under standardized conditions for their suitability as intermediate hosts for Angiostrongylus cantonensis. These species were the planorbid snails Biomphalaria glabrata, Biomphalaria alexandrina, Planorbis planorbis, Planorbis intermixtus, Bulinus truncatus, Bulinus contortus, Bulinus africanus, Bulinus tropicus and Helisoma sp.; the lymnaeid snails Lymnaea natalensis, Lymnaea tomentosa, Lymnaea stagnalis, and Stagnicola elodes; the physid snail Physa acuta (an Egyptian and a German strain) and the ampullariid snails Marisa cornuarietis and Lanistes carinatus. All these snail species proved to be susceptible to infection with A. cantonensis, and first stage larvae reached the infective third stage in all of them. However, the rate and intensity of infection varied with different species. B. glabrata was the most susceptible snail species with a 100% infection rate and an average percentage recovery of third stage larvae of 26.1. This was followed by S. elodes and B. africanus, with a 100% infection rate and an average percentage recovery of third stage larvae of 15.6 and 14.6 respectively. The rest of snail species proved to be less susceptible. For comparative evaluation of the suitability of the various snail species as intermediate hosts of A. cantonensis a "Capacity Index" was determined. This index should provide a useful method for the evaluation of the suitability of various snails as intermediate hosts of nematode parasites under standardized conditions in the laboratory.

Anatomia e histologia do aparelho reprodutor masculino de Pomacea canaliculata (Lamarck, 1822 (Mollusca, Gastropoda, Pilidae

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Eliana de Fátima Marques de Mesquita

1990-01-01

Full Text Available In this paper the authors give an anatomical and histological analysis of the male reproductive system of Pomacea canaliculata (Lamarck, 1822. Anatomically, the testis is better evidentiated than the ovary. In the structure of the testis a great number of very small channels converges to a single one. The male copulatory organs result of transformations that take place in the inner surface on the palial membrane. Histologically, the testis of immature males shows seminiferous ducts with round egg-shaped forms. In their lumens we could notice masses of cells that will originate spermatozoids. The penis has a conjunctive muscular sheath that can be seen in van Gieson's coloured preparations.

Enzootic Angiostrongyliasis in Guangzhou, China, 2008–2010

Science.gov (United States)

Yang, Xiao; Qu, Zhenyu; He, Hualiang; Zheng, Xiaoying; He, Ai; Wu, Yu; Liu, Qian; Zhang, Dongjing; Wu, Zhongdao; Li, Zhuoya; Zhan, Ximei

2012-01-01

This study was conducted to gain an understanding of the Angiostrongylus cantonensis infection status of rodent definitive host, snail intermediate host, and local residents in Guangzhou, China. A total of 430 rats were captured and 23 rats, from two species, were infected, with an average infection rate of 5.35%. A total of 795 Achatina fulica snails and 734 Pomacea canaliculata snails were collected. The average infection rates of these two species were 13.96% (111 of 795) and 1.50% (11 of 734), respectively. As for the seroprevalence of different occupations, the rate among the “general group” was significantly lower than the “occupational group.” From this survey, Guangzhou is implicated to be the natural focus of Angiostrongylus cantonensis. Rattus norvegicus and Achatina fulica play important roles in spreading this nematode in Guangzhou. Residents who live in Guangzhou, especially those working in certain industries such as agriculture, food-making, and aquaculture, face a higher risk of infection. PMID:22556086

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

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Iman Fathy Abou-El-Naga

2015-08-01

Full Text Available 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.

Modulation of defensive reflex conditioning in snails by serotonin

Science.gov (United States)

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

2015-01-01

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

[Application of electronic fence technology based on GIS in Oncomelania hupensis snail monitoring].

Science.gov (United States)

Zhi-Hua, Chen; Yi-Sheng, Zhu; Zhi-Qiang, Xue; Xue-Bing, Li; Yi-Min, Ding; Li-Jun, Bi; Kai-Min, Gao; You, Zhang

2017-07-27

To study the application of Geographic Information System (GIS) electronic fence technique in Oncomelania hupensis snail monitoring. The electronic fence was set around the history and existing snail environments in the electronic map, the information about snail monitoring and controlling was linked to the electronic fence, and the snail monitoring information system was established on these bases. The monitoring information was input through the computer and smart phone. The electronic fence around the history and existing snail environments was set in the electronic map (Baidu map), and the snail monitoring information system and smart phone APP were established. The monitoring information was input and upload real-time, and the snail monitoring information was demonstrated in real time on Baidu map. By using the electronic fence technology based on GIS, the unique "environment electronic archives" for each snail monitoring environment can be established in the electronic map, and real-time, dynamic monitoring and visual management can be realized.

Defense response of susceptible and resistant Biomphalaria alexandrina snails against Schistosoma mansoni infection

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Iman F. Abou-El-Naga

2012-09-01

Full Text Available In Egypt, Biomphalaria alexandrina is the intermediate host for Schistosoma mansoni. The fates of Schistosoma miracidia in the snails varies between different species of Biomphalaria. The internal defense system is one of the factors that influence the susceptibility pattern of the snails. The interaction between Biomphalaria snails and S. mansoni needs to be identified for each species, and even between the members of the same species with different degrees of susceptibility. In the present study, the first generation of susceptible and resistant parents of B. alexandrina was examined histologically at the 30th day post exposure. The study includes the characterization of the immune response, as expressed by tissue reactions, of susceptible and resistant B. alexandrina snails against S. mansoni. It was also designed to determine the impact of the resistance increase in parent snails, on the mechanisms of interaction of their offspring against infection. The results showed that the infection rate of the offspring from the susceptible parents was 92%. No susceptible offspring was produced from the resistant parents. When the parents were of equal number of susceptible and resistant snails, they gave an offspring with an infection rate of 20%. Susceptible snails that had susceptible parents showed a higher degree of susceptibility than those that had both susceptible and resistant parents. A common feature of the resistant snails was the absence of any viable parasites. The tissue reactions of the resistant snails having only resistant parents occurred at the site of miracidial penetration. In resistant snails for which susceptible ones were included in their parents, the reactions occurred in the deep tissues. These results characterized the immune response of B. alexandrina snails against Schistosoma infection which was found to occur by two different mechanisms. One type of defense occurs in highly resistant snails, and employs direct

Ejaculates are not used as nuptial gifts in simultaneously hermaphroditic snails.

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Lodi, Monica; Meijer, Fedde W; Koene, Joris M

2017-08-01

Promoted by sexual selection, males usually adopt different ways to increase their fertilization chances. In many insect taxa males donate nuptial gifts, together with sperm, which represent a valuable additional nutrient source that females can use to provision eggs. This has also been suggested to occur in simultaneous hermaphrodites, organisms with both sex functions. In theory, donation of nuptial gifts or extra nutrients might work in hermaphrodites that mate unilaterally (one-way donation of ejaculates), but will not be effective when these organisms mate reciprocally (mutual exchange of ejaculates), since on average each partner would receive the amount it also transfers. Hence, for the latter the net amount gained would be zero, and when considering the non-trivial costs of metabolic conversion the energy balance of this exchange ends up negative. To test this prediction, we measured the material (dry weight) and resource (carbon and nitrogen content) investment into ejaculates of the unilaterally mating freshwater snail Lymnaea stagnalis and spermatophores of the reciprocally mating land snail Cornu aspersum. When compared to eggs, our measurements indicate that the investment is low for ejaculates and spermatophores, neither of which represent a significant contribution to egg production. Importantly, during reciprocal matings, couples exchanged similar amounts of material and resources, thus a gain of extra substances seems irrelevant. Hence, caution is needed when generalizing functions of male reproductive strategies across mating systems. Although digestion of ejaculates does not provide extra material and resources in simultaneous hermaphrodites, their absorption could still be important to eliminate an excess of received sperm and to select sperm via cryptic female choice. Copyright © 2017 Elsevier GmbH. All rights reserved.

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

Science.gov (United States)

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

2006-04-01

Previous investigations have shown that bisphenol A (BPA) induces a superfeminization syndrome in the freshwater snail Marisa cornuarietis at concentrations as low as 1 microg/L. Superfemales are characterized by the formation of additional female organs, enlarged accessory sex glands, gross malformations of the pallial oviduct, and a stimulation of egg and clutch production, resulting in increased female mortality. However, these studies were challenged on the basis of incomplete experimentation. Therefore, the objective of the current approach was to bridge several gaps in knowledge by conducting additional experiments. In an initial series of experiments, study results from the reproductive phase of the snails were evaluated in the sub-micrograms per liter range. Before and after the spawning season, superfemale responses were observed [NOEC (no observed effect concentration) 7.9 ng/L, EC10 (effective concentration at 10%) 13.9 ng/L], which were absent during the spawning season. A further experiment investigated the temperature dependence of BPA responses by exposing snails at two temperatures in parallel. The adverse effect of BPA was at least partially masked at 27 degrees C (EC10 998 ng/L) when compared with 20 degrees C (EC10 14.8 ng/L). In M. cornuarietis, BPA acts as an estrogen receptor (ER) agonist, because effects were completely antagonized by a co-exposure to tamoxifen and Faslodex. Antiandrogenic effects of BPA, such as a significant decrease in penis length at 20 degrees C, were also observed. Competitive receptor displacement experiments indicate the presence of androgen- and estrogen-specific binding sites. The affinity for BPA of the estrogen binding sites in M. cornuarietis is higher than that of the ER in aquatic vertebrates. The results emphasize that prosobranchs are affected by BPA at lower concentrations than are other wildlife groups, and the findings also highlight the importance of exposure conditions.

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

Science.gov (United States)

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

2013-07-01

Tributyltin (TBT) and triphenyltin (TPT) are emblematic endocrine disruptors, which have been mostly studied in gonochoric prosobranchs. Although both compounds can simultaneously occur in the environment, they have mainly been tested separately for their effects on snail reproduction. Because large discrepancies in experimental conditions occurred in these tests, the present study aimed to compare the relative toxicity of TBT and TPT under similar laboratory conditions in the range of 0 ng Sn/L to 600 ng Sn/L. Tests were performed on the simultaneous hermaphrodite Lymnaea stagnalis, a freshwater snail in which effects of TPT were unknown. Survival, shell length, and reproduction were monitored in a 21-d semistatic test. Frequency of abnormal eggs was assessed as an additional endpoint. Triphenyltin hampered survival while TBT did not. Major effects on shell solidity and reproduction were observed for both compounds, reproductive outputs being more severely hampered by TBT than by TPT. Considering the frequency of abnormal eggs allowed increasing test sensitivity, because snail responses to TBT could be detected at concentrations as low as 19 ng Sn/L. However, the putative mode of action of the 2 compounds could not be deduced from the structure of the molecules or from the response of apical endpoints. Sensitivity of L. stagnalis to TBT and TPT was compared with the sensitivity of prosobranch mollusks with different habitats and different reproductive strategies. Copyright © 2013 SETAC.

Socio-Economic Characteristics Of Snail Farmers, Consumers And ...

African Journals Online (AJOL)

The socio-economic characteristic of snail farmers in Oyo State Agricultural Development Programme (ADP) was evaluated in two out of the four zones that were available. The two zones selected were Ibadan/Ibarapa and Oyo zones, to determine the factors related to snail production, consumption and marketing in the ...

Snail arboreality: the microdistribution of Sitala jenynsi (Gastropoda ...

African Journals Online (AJOL)

The habitats and patterns of vertical migration of the shell banding morphs of the snail Sitala jenynsi (Pfeiffer) were studied in Dar es Salaam and Wazo regions of central coastal Tanzania Both dimorphic and trimorphic populations were arboreal throughout the year. The snails occurred randomly within mid-heights 180 to ...

[Analysis of trend of Oncomelania snail status in Yangtze River valley of Anhui Province, 1998-2009].

Science.gov (United States)

He, Jia-Chang; Wang, Jia-Sheng; Lu, Jin-You; Li, Ting-Ting; Gao, Feng-Hu; Zhou, Ping; Zhu, Chuan-Ming; He, Long-Zhu; Yu, Bei-Bei; Zhang, Shi-Qing

2011-04-01

To understand the trend of Oncomelania hupensis snail distribution in Yangtze River valley of Anhui Province so as to provide an evidence for making out schistosomiasis prevention and control strategies in the future. The snail data from 1998 to 2009 of the Yangtze River valley in Anhui Province were collected including the snail area, newly occurred and re-occurred snail areas, densities of snails and infected snails, etc., and the trend and influence factors were analyzed. With several fluctuations, the snail area showed a trend of declining in general after the devastating summer flooding in 1998. From 1998 to 2009, 3 peaks of newly occurred snail areas appeared in 1998, 2004 and 2006 and 2 peaks of reoccurred snail areas appeared in 1998 and 2004. The densities of living snails and infected snails were more severe in banks of the Yangtze River than in islets of the Yangtze River. During 12 years, 1 peak of living snail density appeared in 2003, and 3 peaks of infected snail density appeared in 1999, 2003-2004 and 2006 in the islets of the Yangtze River. The densities of living snails and infected snails in banks of the Yangtze both appeared 1 peak in 1998. The distribution of snails in the Yangtze River valley is related to nature, society and financial circumstances, and it is hard to completely perform the snail control in a short-term. Therefore, at the same time of strengthening snail control, we should also strengthen infectious source control.

Celss nutrition system utilizing snails

Science.gov (United States)

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.

Implication of snail in metabolic stress-induced necrosis.

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Cho Hee Kim

2011-03-01

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

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

Science.gov (United States)

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. © 2016 Society for Conservation Biology.

Biochemical evaluation of aestivation and starvation in two snail ...

African Journals Online (AJOL)

hope&shola

2010-11-08

Nov 8, 2010 ... food uptake ceases, water loss occurs and the snails are not able to rid .... Fasting glucose decreased in both aestivating and starved B. rohlfsi snails ... significant muscle wastage during aestivation and starvation. It has been ...

Nutritional Assessment of Some Nigerian Land and Water Snail ...

African Journals Online (AJOL)

Choice-Academy

lapillus) snail species for nutritional assessment using their muscular foot tissues. The mean of ... Kwashiorkor is a protein – energy malnutrition that occurs ... analyses from the same pool of snails. ... due to the fact that swimming in water is a.

Submerged macrophytes mitigate direct and indirect insecticide effects in freshwater communities.

Science.gov (United States)

Brogan, William R; Relyea, Rick A

2015-01-01

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

Submerged Macrophytes Mitigate Direct and Indirect Insecticide Effects in Freshwater Communities

Science.gov (United States)

Brogan, William R.; Relyea, Rick A.

2015-01-01

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

Submerged macrophytes mitigate direct and indirect insecticide effects in freshwater communities.

Directory of Open Access Journals (Sweden)

William R Brogan

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

MTA3 regulates CGB5 and Snail genes in trophoblast

Energy Technology Data Exchange (ETDEWEB)

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

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

MTA3 regulates CGB5 and Snail genes in trophoblast

International Nuclear Information System (INIS)

Chen, Ying; Miyazaki, Jun; Nishizawa, Haruki; Kurahashi, Hiroki; Leach, Richard; Wang, Kai

2013-01-01

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

A snail-eating snake recognizes prey handedness.

Science.gov (United States)

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

2016-04-05

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.

Local adaptation of the trematode Fasciola hepatica to the snail Galba truncatula

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Dreyfuss G.

2012-08-01

Full Text Available Experimental infections of six riverbank populations of Galba truncatula with Fasciola hepatica were carried out to determine if the poor susceptibility of these populations to this digenean might be due to the scarcity or the absence of natural encounters between these snails and the parasite. The first three populations originated from banks frequented by cattle in the past (riverbank group whereas the three others were living on islet banks without any known contact with local ruminants (islet group. After their exposure, all snails were placed in their natural habitats from the end of October up to their collection at the beginning of April. Compared to the riverbank group, snails, which died without cercarial shedding clearly predominated in the islet group, while the other infected snails were few in number. Most of these last snails released their cercariae during a single shedding wave. In islet snails dissected after their death, the redial and cercarial burdens were significantly lower than those noted in riverbank G. truncatula. Snails living on these islet banks are thus able to sustain larval development of F. hepatica. The modifications noted in the characteristics of snail infection suggest the existence of an incomplete adaptation between these G. truncatula and the parasite, probably due to the absence of natural contact between host and parasite.

A preliminary checklist of the freshwater snails of Sabah (Malaysian Borneo) deposited in the BORNEENSIS collection, Universiti Malaysia Sabah

Science.gov (United States)

Ng, Ting Hui; Dulipat, Jasrul; Foon, Junn Kitt; Lopes-Lima, Manuel; Alexandra Zieritz; Liew, Thor-Seng

2017-01-01

Abstract Sabah, a Malaysian state at the north-eastern tip of Borneo, is situated in one of the Earth’s biodiversity hotspots yet its freshwater gastropod diversity remains poorly known. An annotated checklist of the freshwater gastropods is presented, based on specimens deposited in the BORNEENSIS collection of the Institute for Tropical Biology and Conservation at Universiti Malaysia Sabah, Malaysia. A KMZ file is also provided, which acts as a repository of digital images and complete collection data of all examined material, so that it can be shared and adapted to facilitate future research. PMID:28769673

A preliminary checklist of the freshwater snails of Sabah (Malaysian Borneo deposited in the BORNEENSIS collection, Universiti Malaysia Sabah

Directory of Open Access Journals (Sweden)

Ting Hui Ng

2017-05-01

Full Text Available Sabah, a Malaysian state at the north-eastern tip of Borneo, is situated in one of the Earth’s biodiversity hotspots yet its freshwater gastropod diversity remains poorly known. An annotated checklist of the freshwater gastropods is presented, based on specimens deposited in the BORNEENSIS collection of the Institute for Tropical Biology and Conservation at Universiti Malaysia Sabah, Malaysia. A KMZ file is also provided, which acts as a repository of digital images and complete collection data of all examined material, so that it can be shared and adapted to facilitate future research.

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

Science.gov (United States)

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.

Salinization triggers a trophic cascade in experimental freshwater communities with varying food-chain length.

Science.gov (United States)

Hintz, William D; Mattes, Brian M; Schuler, Matthew S; Jones, Devin K; Stoler, Aaron B; Lind, Lovisa; Relyea, Rick A

2017-04-01

The application of road deicing salts in northern regions worldwide is changing the chemical environment of freshwater ecosystems. Chloride levels in many lakes, streams, and wetlands exceed the chronic and acute thresholds established by the United States and Canada for the protection of freshwater biota. Few studies have identified the impacts of deicing salts in stream and wetland communities and none have examined impacts in lake communities. We tested how relevant concentrations of road salt (15, 100, 250, 500, and 1000 mg Cl - /L) interacted with experimental communities containing two or three trophic levels (i.e., no fish vs. predatory fish). We hypothesized that road salt and fish would have a negative synergistic effect on zooplankton, which would then induce a trophic cascade. We tested this hypothesis in outdoor mesocosms containing filamentous algae, periphyton, phytoplankton, zooplankton, several macroinvertebrate species, and fish. We found that the presence of fish and high salt had a negative synergistic effect on the zooplankton community, which in turn caused an increase in phytoplankton. Contributing to the magnitude of this trophic cascade was a direct positive effect of high salinity on phytoplankton abundance. Cascading effects were limited with respect to impacts on the benthic food web. Periphyton and snail grazers were unaffected by the salt-induced trophic cascade, but the biomass of filamentous algae decreased as a result of competition with phytoplankton for light or nutrients. We also found direct negative effects of high salinity on the biomass of filamentous algae and amphipods (Hyalella azteca) and the mortality of banded mystery snails (Viviparus georgianus) and fingernail clams (Sphaerium simile). Clam mortality was dependent on the presence of fish, suggesting a non-consumptive interactive effect with salt. Our results indicate that globally increasing concentrations of road salt can alter community structure via both direct

Confocal Raman and electronic microscopy studies on the topotactic conversion of calcium carbonate from Pomacea lineate shells into hydroxyapatite bioceramic materials in phosphate media.

Science.gov (United States)

dePaula, S M; Huila, M F G; Araki, K; Toma, H E

2010-12-01

Conversion of Pomacea lineate shells into hydroxyapatite (HA) bioceramic materials was investigated by their in vitro treatment with phosphate solutions, at room temperature. Confocal Raman microscopy revealed that the conversion proceeds at distinct rates through the nacreous or periostracum sides of the shell. The conversion can be accelerated using powdered samples, yielding biocompatible materials of great interest in biomedicine. Copyright © 2010 Elsevier Ltd. All rights reserved.

Herbivorous snails can increase water clarity by stimulating growth of benthic algae.

Science.gov (United States)

Zhang, Xiufeng; Taylor, William D; Rudstam, Lars G

2017-11-01

Eutrophication in shallow lakes is characterized by a switch from benthic to pelagic dominance of primary productivity that leads to turbid water, while benthification is characterized by a shift in primary production from the pelagic zone to the benthos associated with clear water. A 12-week mesocosm experiment tested the hypothesis that the herbivorous snail Bellamya aeruginosa stimulates the growth of pelagic algae through grazing on benthic algae and through accelerating nutrient release from sediment. A tube-microcosm experiment using 32 P-PO 4 as a tracer tested the effects of the snails on the release of sediment phosphorus (P). The mesocosm experiment recorded greater total nitrogen (TN) concentrations and a higher ratio of TN:TP in the overlying water, and a higher light intensity and biomass of benthic algae as measured by chlorophyll a (Chl a) in the snail treatment than in the control. Concentrations of total phosphorus (TP), total suspended solids (TSSs), and inorganic suspended solids (ISSs) in the overlying water were lower in the snail treatment than in the control, though no significant difference in Chl a of pelagic algae between the snail treatment and control was observed. In the microcosm experiment, 32 P activity in the overlying water was higher in the snail treatment than in the control, indicating that snails accelerated P release from the sediment. Our interpretation of these results is that snails enhanced growth of benthic algae and thereby improved water clarity despite grazing on the benthic algae and enhancing P release from the sediment. The rehabilitation of native snail populations may therefore enhance the recovery of eutrophic shallow lakes to a clear water state by stimulating growth of benthic algae.

The influence of physico-chemical and ecological factors on the ...

African Journals Online (AJOL)

A survey was conducted to determine the influence of physico-chemical parameters on the distribution of freshwater snails in Manchok water intake, Kaduna State, Nigeria from January 2013 to December, 2013. A total of eight thousand, three hundred and forty one (8341) freshwater snails were collected using a long ...

Herbivore preference for native vs. exotic plants: generalist herbivores from multiple continents prefer exotic plants that are evolutionarily naïve.

Directory of Open Access Journals (Sweden)

Wendy E Morrison

2011-03-01

Full Text Available Enemy release and biotic resistance are competing, but not mutually exclusive, hypotheses addressing the success or failure of non-native plants entering a new region. Enemy release predicts that exotic plants become invasive by escaping their co-adapted herbivores and by being unrecognized or unpalatable to native herbivores that have not been selected to consume them. In contrast, biotic resistance predicts that native generalist herbivores will suppress exotic plants that will not have been selected to deter these herbivores. We tested these hypotheses using five generalist herbivores from North or South America and nine confamilial pairs of native and exotic aquatic plants. Four of five herbivores showed 2.4-17.3 fold preferences for exotic over native plants. Three species of South American apple snails (Pomacea sp. preferred North American over South American macrophytes, while a North American crayfish Procambarus spiculifer preferred South American, Asian, and Australian macrophytes over North American relatives. Apple snails have their center of diversity in South America, but a single species (Pomacea paludosa occurs in North America. This species, with a South American lineage but a North American distribution, did not differentiate between South American and North American plants. Its preferences correlated with preferences of its South American relatives rather than with preferences of the North American crayfish, consistent with evolutionary inertia due to its South American lineage. Tests of plant traits indicated that the crayfish responded primarily to plant structure, the apple snails primarily to plant chemistry, and that plant protein concentration played no detectable role. Generalist herbivores preferred non-native plants, suggesting that intact guilds of native, generalist herbivores may provide biotic resistance to plant invasions. Past invasions may have been facilitated by removal of native herbivores, introduction of

Species diversity of Plagiorchis Luhe, 1899 (Digenea: Plagiorchiidae) in lymnaeid snails from freshwater ecosystems in central Europe revealed by molecules and morphology

Czech Academy of Sciences Publication Activity Database

Zikmundová, Jana; Georgieva, Simona; Faltýnková, Anna; Soldánová, Miroslava; Kostadinova, Aneta

2014-01-01

Roč. 88, č. 1 (2014), s. 37-54 ISSN 0165-5752 R&D Projects: GA ČR GAP505/10/1562; GA ČR GBP505/12/G112 Institutional support: RVO:60077344 Keywords : larval trematodes digenea * partial lsrDNA sequences * great pond snail * maximum-likelihood * Lymnea stagnalis * life -cycle * platyhelminthes * differentiation * omphalometridae * phylogenies Subject RIV: EH - Ecology, Behaviour Impact factor: 1.336, year: 2014

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

Science.gov (United States)

Williams, Dana E; 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 m(2) plots. Snails were removed three additional times during a seven month "removal phase", then counted at five surveys over the next 19 months to track recolonization. At the conclusion, snails were collected, measured and sexed. Before-After-Control-Impact analysis revealed that both snail abundance and feeding scar prevalence were reduced in removal treatments compared to the control, but there was no difference between removal treatments. Recolonization by snails to baseline abundance is estimated to be 3.7 years and did not differ between removal treatments. Recolonization rate was significantly correlated with baseline snail abundance. Maximum snail size decreased from 47.0 mm to 34.6 mm in the removal treatments. The effort required to remove snails from A. palmata was 30 diver minutes per 150 m(2) plot, compared with 51 min to remove snails from all host corals. Since there was no additional benefit observed with removing snails from all host species, removals can be more efficiently focused on only A. palmata colonies and in areas where C. abbreviata abundance is high, to effectively conserve A. palmata in targeted areas.

Linking embryo toxicity with genotoxic responses in the freshwater snail Physa acuta: single exposure to benzo(a)pyrene, fluoxetine, bisphenol A, vinclozolin and exposure to binary mixtures with benzo(a)pyrene.

Science.gov (United States)

Sánchez-Argüello, Paloma; Aparicio, Natalia; Fernández, Carlos

2012-06-01

development of a life cycle test with freshwater snails even for undertaking multigeneration studies focused on transgenerational effects. Copyright © 2012 Elsevier Inc. All rights reserved.

ATM-mediated Snail Serine 100 phosphorylation regulates cellular radiosensitivity

International Nuclear Information System (INIS)

Boohaker, Rebecca J.; Cui, Xiaoli; Stackhouse, Murray; Xu, Bo

2013-01-01

Purpose: Activation of the DNA damage responsive protein kinase ATM is a critical step for cellular survival in response to ionizing irradiation (IR). Direct targets of ATM regulating radiosensitivity remain to be fully investigated. We have recently reported that ATM phosphorylates the transcriptional repressor Snail on Serine 100. We aimed to further study the functional significance of ATM-mediated Snail phosphorylation in response to IR. Material and methods: We transfected vector-only, wild-type, the Serine 100 to alanine (S100A) or to glutamic acid (S100E) substitution of Snail into various cell lines. We assessed colony formation, γ-H2AX focus formation and the invasion index in the cells treated with or without IR. Results: We found that over-expression of the S100A mutant Snail in HeLa cells significantly increased radiosensitivity. Meanwhile the expression of S100E, a phospho-mimicking mutation, resulted in enhanced radio-resistance. Interestingly, S100E could rescue the radiosensitive phenotype in ATM-deficient cells. We also found that expression of S100E increased γ-H2AX focus formation and compromised inhibition of invasion in response to IR independent of cell survival. Conclusion: ATM-mediated Snail Serine 100 phosphorylation in response to IR plays an important part in the regulation of radiosensitivity

Trace metallic elements in Helix aspersa terrestrial snails of a semiarid ecosystem

International Nuclear Information System (INIS)

Gaso P, M.I.; Segovia, N.; Zarazua, G.; Montes, F.; Morton, O.; Armienta, M.A.; Hernandez, E.

2001-01-01

The concentration of some major elements and traces in soil samples and of Helix aspersa eatable terrestrial snails were analysed at the Radioactive Wastes Storage Center (CADER) and in other reference sites. The methodology includes the use of an atomic absorption spectrophotometer, an X-ray fluorescence equipment and an Icp-mass spectroscope. The concentrations of some toxic elements (Ba, Cd, Cr, Ni, Pb and V) in the soft tissue of the snails were greater than the toxic levels reported in the literature for such trace elements. The snails compared with another wild eatable foods present transfer coefficients soil-snail high relatively. (Author)

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

Science.gov (United States)

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

1998-03-01

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

Arsenic transfer and impacts on snails exposed to stabilized and untreated As-contaminated soils

International Nuclear Information System (INIS)

Coeurdassier, M.; Scheifler, R.; Mench, M.; Crini, N.; Vangronsveld, J.; Vaufleury, A. de

2010-01-01

An As-contaminated soil (Unt) was amended with either iron grit (Z), a coal fly ash (beringite, B) or B + Z (BZ) and placed in lysimeters in 1997. An uncontaminated soil (R) was also studied. In summer and autumn 2003, lettuces were cultivated in the lysimeters and snails were caged for one month. Lettuce As concentrations were higher during the summer, while no differences occurred in snails between seasons. Snail As concentrations (μg g -1 DW) ranged from 2.5 to 7.0 in B, Z and BZ, and peaked at 17.5 in Unt. In summer, snail survival was affected in Unt and Z compared to R and B while no mortality was noticed in autumn. Snail growth decreased only in B, BZ and Unt in autumn. Snail As concentrations suggest a risk for their predators even on the remediated soils. - The addition of beringite along with iron grit into an As-contaminated soil decreases As transfer to and impacts on snails.

Nutritive potentials and utilization of garden snail (Limicolaria aurora ...

African Journals Online (AJOL)

The possibility of using garden snail (Limicolaria aurora) meat meal as a protein source in fish feeds was tested in Clarias gariepinus fingerlings. Five isonitrogenous (43% crude protein) diets in which garden snail meat meal was used to replace fish meal at 0%, (control diet), 25, 50, 75 and 100% inclusion levels were used ...

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

Directory of Open Access Journals (Sweden)

Dana E. Williams

2014-11-01

Full Text Available 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.

Host density increases parasite recruitment but decreases host risk in a snail-trematode system.

Science.gov (United States)

Buck, J C; Hechinger, R F; Wood, A C; Stewart, T E; Kuris, A M; Lafferty, K D

2017-08-01

Most species aggregate in local patches. High host density in patches increases contact rate between hosts and parasites, increasing parasite transmission success. At the same time, for environmentally transmitted parasites, high host density can decrease infection risk to individual hosts, because infective stages are divided among all hosts in a patch, leading to safety in numbers. We tested these predictions using the California horn snail, Cerithideopsis californica (=Cerithidea californica), which is the first intermediate host for at least 19 digenean trematode species in California estuaries. Snails become infected by ingesting trematode eggs or through penetration by free-swimming miracidia that hatch from trematode eggs deposited with final-host (bird or mammal) feces. This complex life cycle decouples infective-stage production from transmission, raising the possibility of an inverse relationship between host density and infection risk at local scales. In a field survey, higher snail density was associated with increased trematode (infected snail) density, but decreased trematode prevalence, consistent with either safety in numbers, parasitic castration, or both. To determine the extent to which safety in numbers drove the negative snail-density-trematode-prevalence association, we manipulated uninfected snail density in 83 cages at eight sites within Carpinteria Salt Marsh (California, USA). At each site, we quantified snail density and used data on final-host (bird and raccoon) distributions to control for between-site variation in infective-stage supply. After three months, overall trematode infections per cage increased with snail biomass density. For egg-transmitted trematodes, per-snail infection risk decreased with snail biomass density in the cage and surrounding area, whereas per-snail infection risk did not decrease for miracidium-transmitted trematodes. Furthermore, both trematode recruitment and infection risk increased with infective

Reciprocal Regulation between DNA-PKcs and Snail1 Conferring Genomic Instability

International Nuclear Information System (INIS)

Seo, Haeng Ran; Lee, Hae June; Jin, Yeung Bae; Bae, Sang Woo; Lee, Yun Sil; Kim, Nam Hee; Kim, Hyun Sil; Nam, Hyung Wook; Yook, Jong In

2010-01-01

Although the roles of DNA-dependent protein kinase catalytic subunit (DNA-PKcs) involving non-homologous end joining (NHEJ) of DNA repair are well recognized, the biological mechanisms and regulators by which DNA-PKcs regulate genomic instability are not clearly defined. We show herein that DNA-PKcs activity resulting from DNA damage caused by ionizing radiation (IR) phosphorylates Snail1 at serine 100, which results in increased Snail1 expression and its function by inhibition of GSK-3-mediated phosphorylation. Furthermore, Snail1 phosphorylated at serine 100 can reciprocally inhibit kinase activity of DNA-PKcs, resulting in an inhibition to recruit DNA-PKcs or Ku70/80 to a DNA double-strand break site, and ultimately inhibition of DNA repair activity. The impairment of repair activity by a direct interaction between Snail1 and DNA-PKcs increases the resistance to DNA damaging agents, such as IR, and genomic instability. Our findings provide a novel cellular mechanism for induction of genomic instability by reciprocal regulation of DNA-PKcs and Snail1

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

Science.gov (United States)

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.

Nutritive potentials and utilization of garden snail (Limicolaria aurora ...

African Journals Online (AJOL)

AJB SERVER

2006-10-16

Oct 16, 2006 ... The possibility of using garden snail (Limicolaria aurora) meat meal as a protein source in fish feeds was tested in ... garden snail meat meal was used to replace fish meal at 0%, (control diet), 25, 50, 75 and 100% inclusion ..... Randall DJ, Brett JR (eds) Fish Physiology, Academic Press, NY 8: 279-352,.

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

DEFF Research Database (Denmark)

Villarejo, Ana; Molina-Ortiz, Patricia; Montenegro, Yenny

2015-01-01

showed that loss of Snail2 leads to a decrease in proliferation indicating a non-cell autonomous role for Snail2 in the skin carcinogenic response observed in vivo. Bone marrow (BM) cross-reconstitution assays between Snail2 wild-type and null mice showed that Snail2 absence in the hematopoietic system...

Freshwater Megafauna: Flagships for Freshwater Biodiversity under Threat.

Science.gov (United States)

Carrizo, Savrina F; Jähnig, Sonja C; Bremerich, Vanessa; Freyhof, Jörg; Harrison, Ian; He, Fengzhi; Langhans, Simone D; Tockner, Klement; Zarfl, Christiane; Darwall, William

2017-10-01

Freshwater biodiversity is highly threatened and is decreasing more rapidly than its terrestrial or marine counterparts; however, freshwaters receive less attention and conservation investment than other ecosystems do. The diverse group of freshwater megafauna, including iconic species such as sturgeons, river dolphins, and turtles, could, if promoted, provide a valuable tool to raise awareness and funding for conservation. We found that freshwater megafauna inhabit every continent except Antarctica, with South America, Central Africa, and South and Southeast Asia being particularly species rich. Freshwater megafauna co-occur with up to 93% of mapped overall freshwater biodiversity. Fifty-eight percent of the 132 megafauna species included in the study are threatened, with 84% of their collective range falling outside of protected areas. Of all threatened freshwater species, 83% are found within the megafauna range, revealing the megafauna's capacity as flagship and umbrella species for fostering freshwater conservation.

Community ecology of tropical forest snails: 30 years after Solem

NARCIS (Netherlands)

Schilthuizen, M.

2011-01-01

Since Solem’s provocative claim in the early 1980s that land snails in tropical forests are neither abundant nor diverse, at least 30 quantitative-ecological papers on tropical land snail communities have appeared. Jointly, these papers have shown that site diversity is, in fact, high in tropical

Arsenic transfer and impacts on snails exposed to stabilized and untreated As-contaminated soils

Energy Technology Data Exchange (ETDEWEB)

Coeurdassier, M.; Scheifler, R.; Mench, M.; Crini, N.; Vangronsveld, J.; de Vaufleury, A. [Universite de Franche-Comte, Besancon (France)

2010-06-15

An As-contaminated soil (Unt) was amended with either iron grit (Z), a coal fly ash (beringite, B) or B + Z (BZ) and placed in lysimeters in 1997. An uncontaminated soil (R) was also studied. In summer and autumn 2003, lettuces were cultivated in the lysimeters and snails were caged for one month. Lettuce As concentrations were higher during the summer, while no differences occurred in snails between seasons. Snail As concentrations ({mu} g g{sup -1} DW) ranged from 2.5 to 7.0 in B, Z and BZ, and peaked at 17.5 in Unt. In summer, snail survival was affected in Unt and Z compared to R and B while no mortality was noticed in autumn. Snail growth decreased only in B, BZ and Unt in autumn. Snail As concentrations suggest a risk for their predators even on the remediated soils.

First report of Temnocephala haswelli (Platyhelminthes: Temnocephalida in Pomacea canaliculata (Mollusca: Ampullariidae from Brazil: description update based on specimens from the state of Rio Grande do Sul, Brazil

Directory of Open Access Journals (Sweden)

Samantha A. Seixas

2010-06-01

Full Text Available The impact of the discovery of Temnocephala haswelli Ponce de Léon, 1989, described as ectosymbionts of ampullariid apple snails outside of Uruguay, motivated us to collect a large number of specimens of Pomacea canaliculata (Lamarck, 1822 from several localities in the southern portion of the state of Rio Grande do Sul. This species was recorded three times after its description: in a study of chromosomes, in a study about the ultrastructure of the collar receptor cells, and in a study of the Haswell glands, all conducted in Uruguay. A total of 301 specimens of P. canaliculata were collected from 1999 to 2007. Temnocephalans found in the pallial cavity were identified as T. haswelli, which occurred in single infestations or concurrently with Temnocephala iheringi Haswell, 1893. Helminths usually showed a light-orange body pigmentation and conspicuous, intense red-eye pigment. Many taxonomic characters evidenced by several techniques were documented photographically for the first time. The typical curved cirrus, approximately 90°, typical of the species, showed some variation in the width of the shaft base, whereas the first longitudinal row of spines of the introvert appeared with shorter spines. The vagina was found to be thick-walled, but not very muscular, and to have a single, large and slightly asymmetrical sphincter, with the posterior portion of slightly larger diameter. Eggs were observed in the umbilicus and along the suture, but predominantly in the body whorl of the shell. Egg peduncles were found to be very short or, most of the time, the eggs were sessile, always with a long apical filament. The rounded shape of the dorsolateral 'excretory' syncytial epidermal plates had external margins reaching the ventrolateral region of the body and eccentric nephridiopores. This is the first record of the species outside Uruguay and in Brazil.

Weak involvement of octopamine in aversive taste learning in a snail.

Science.gov (United States)

Aonuma, Hitoshi; Kaneda, Mugiho; Hatakeyama, Dai; Watanabe, Takayuki; Lukowiak, Ken; Ito, Etsuro

2017-05-01

The pond snail Lymnaea stagnalis is capable of learning taste aversion by pairing presentations of a sucrose solution and an electric shock and consolidating it into long-term memory (LTM), which is referred to as conditioned taste aversion (CTA). We asked here if the neurotransmitter octopamine is involved in CTA. We first determined the levels of octopamine and its catabolites in the central nervous system (CNS) of snails with varying degrees of food deprivation, because CTA grades are correlated with degrees of food deprivation. We next manipulated the octopamine signaling using both an agonist and an antagonist of octopamine receptors and correlated their respective effects with CTA grades. We found that snails with the least amount of food-deprivation obtained the best CTA grade and had low levels of octopamine; whereas the most severely food-deprived snails did not form CTA and had the highest CNS octopamine levels. In modestly food-deprived snails, octopamine application increased the basal level of feeding response to a sucrose solution, and it did not obstruct CTA formation. Application of phentolamine, an octopamine receptor antagonist, to the most severely food-deprived snails decreased the basal level of feeding elicited by sucrose, but it did not enhance CTA formation. We conclude that octopamine involvement in CTA formation in Lymnaea is at best weak, and that the changes in CNS octopamine content are an epiphenomenon. Copyright © 2017 Elsevier Inc. All rights reserved.

Algumas observações de campo sobre biologia e ecologia de Pomacea haustrum (Reeve, 1856 (Mollusca, Pilidae Some field observation on biology and ecology of Pomacea haustrum (Reeve, 1856 (Mollusca, Pilidae

Directory of Open Access Journals (Sweden)

Carlos Tito Guimarães

1981-12-01

Full Text Available Algumas observações de campo sobre o pilídeo Pomacea haustrum (Reeve, 1856, predador-competidor de planorbíneos hospedeiros intermediários da esquistossomose mansoni mostraram que: Cópula e oviposição são realizadas, preferencialmente, à noite e de madrugada. As desovas - cujas dimensões e formas dependem do número de ovos e tipos dos suportes - sao ovipostas, na maioria das vezes, de 6 a 10 cm acima do nível da água eclodindo após 9 a 30 dias de incubação; o número médio de ovos por desova foi de 236. A alimentação habitual deste molusco consiste de algas confervóides, além de vegetais aquáticos natantes e submersos; entretanto, e comum a utilização de outros materiais como alimento.Tem como habitat a zona marginal mais rasa das coleções hídricas onde e encontrado, predominando, aparentemente, nos ambientes lênticos. A distribuição espacial esta condicionada por determinadas características dos biótopos. Algumas aves aquáticas - anatídeos, ralídeos, etc.- revelaram-se importantes inimigos naturais, atacando além das desovas exemplares jovens e adultos; em determinadas condições podem constituir fator impeditivo da implantação e colonização de novos biótopos.Some field observations on the pilid Pomacea haustrum (Reeve, 1856, predator-competitor of schistosomiasis mansoni planorbid intermediate hosts have shown that: Copula and oviposition are preferably carried out at night or at dawn. Eggmasses - whose dimension and shape depend on the number of eggs and types of supports - are often laid from 6 to 10 com above the water level and hatched 9 to 30 days after incubation; the average number of eggs/egg-mass was 236. Habitual food consist of confervoid algae, besides natant and submerged aquatic vegetation; it is common, however, the utilization of the other material as food. Its habitat is the shallower marginal zone of hidric collections, predominatly in lentic surrounding. Its spacial distribution is

Calcium, snails, and birds: a case study

Directory of Open Access Journals (Sweden)

R. Mänd

2000-10-01

Full Text Available Recent studies have shown that wild birds breeding in acidified areas have difficulties with obtaining sufficient calcium for their eggshells, and that the cause of it is the shortage of land snails. Many birds have to search for Ca-rich snail shells on a daily basis during egg production. Molluscs depend on litter calcium, which has decreased due to acidification of the environment. Calcium limitation may be a widespread phenomenon also in non-acidified, naturally Ca-poor areas. The problem is that while in the latter areas the time for development of specific adaptations may have been sufficient, then in acidified areas, on the contrary, calcium shortage is a recent phenomenon. Therefore, since the extent of calcium limitation in non-acidified areas is hard to derive from observational data, experimental approach is needed. We provide experimental evidence that specific calcium deficit does affect reproductive traits also in the birds breeding in naturally base-poor habitats. Our study was conducted in a heterogeneous woodland area in Estonia containing deciduous forest patches as well as base-poor pine forest with low snail abundance. Ca supplementation, using snail shell and chicken eggshell fragments, was carried out for pied flycatchers and great tits. Extra calcium affected positively several reproductive traits like egg volume and eggshell thickness, start of breeding, and fledglings’ parameters. The negative relationship between calcium availability and lay-date suggests that birds adjust their breeding tactics to conditions of Ca deficiency, for example, by postponing laying.

Analysis of land snail marketing in Owerri agricultural zone of Imo ...

African Journals Online (AJOL)

Analysis of land snail marketing in Owerri agricultural zone of Imo state, ... The study was conducted in Owerri Agricultural Zone of Imo state, Nigeria to assess the profitability of snail marketing during ... EMAIL FULL TEXT EMAIL FULL TEXT

Nuclear expression of Snail1 in borderline and malignant epithelial ovarian tumours is associated with tumour progression

International Nuclear Information System (INIS)

Tuhkanen, Hanna; Soini, Ylermi; Kosma, Veli-Matti; Anttila, Maarit; Sironen, Reijo; Hämäläinen, Kirsi; Kukkonen, Laura; Virtanen, Ismo; Mannermaa, Arto

2009-01-01

Transcription factor Snail1 has a central role in induction of epithelial-mesenchymal transition (EMT). The aim of the present study was to elucidate the expression of Snail1 protein during epithelial ovarian tumourigenesis and to study the association of Snail1 expression with clinicopathological factors and prognosis. Epithelial and stromal fibroblast-like fusiform cells of 14 normal ovarian samples, 21 benign, 24 borderline and 74 malignant epithelial ovarian tumours were studied for Snail1 protein using immunohistochemistry. Nuclei of surface peritoneal cells of normal ovaries (n = 14) were regarded as negative for Snail1. Nuclear expression of Snail1 protein in epithelial ovarian tumours was increased during tumour progression from precursor lesions into carcinomas both in epithelial (p = 0.006) and stromal cells (p = 0.007). Nuclei of benign tumours (n = 21) were negative for Snail1. In borderline tumours (n = 24) occasional positive epithelial cells were found in 2 (8%) samples and in 3 (13%) samples stromal cells were focally positive for Snail1. In carcinomas (n = 74) focal Snail1 staining in epithelial cells was present in 17 (23%) tumours, and in stromal cells in 18 (24%) tumours. Nuclear expression of Snail1 in epithelial or stromal cells was not associated with clinicopathological factors or prognosis. Nuclear Snail1 expression seems to be related to tumour progression, and expression in borderline tumours indicates a role for Snail1 in early epithelial ovarian tumour development. Snail1 also appears to function more generally in tissue remodelling as positive staining was demonstrated in stromal cells

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

Science.gov (United States)

Sidel'nikov, A P; Stepanov, I I

2000-01-01

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

Kinetic and dynamic aspects of soil-plant-snail transfer of cadmium in the field

International Nuclear Information System (INIS)

Gimbert, Frederic; Mench, Michel; Coeurdassier, Michael; Badot, Pierre-Marie; Vaufleury, Annette de

2008-01-01

The proper use of bioaccumulation in the assessment of environmental quality involves accounting for chemical fluxes in organisms. Cadmium (Cd) accumulation kinetics in a soil-plant-snail food chain were therefore investigated in the field under different soil contamination (from 0 to 40 mg kg -1 ), soil pH (6 and 7) and season. Allowing for an accurate and sensitive assessment of Cd transfer to snails, toxicokinetics appears an interesting tool in the improvement of risk assessment procedures and a way to quantify metal bioavailability for a defined target. On the basis of uptake fluxes, snails proved to be sensitive enough to distinguish moderate soil contaminations. The soil pH did not appear, in the range studied, as a modulating parameter of the Cd transfer from soil to snail whereas the season, by influencing the snail mass, may modify the internal concentrations. The present data specifying a time integrated assessment of environmental factors on metal bioavailability and transfer to terrestrial snails should ensure their rational use in environmental biomonitoring. - Toxicokinetics and uptake fluxes can be used to describe the environment contamination by Cd, its bioavailability and transfer to Helix aspersa snails in the field

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

Science.gov (United States)

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. Copyright © 2011 Australian Society for Parasitology Inc. All rights reserved.

Snail recruits Ring1B to mediate transcriptional repression and cell migration in pancreatic cancer cells.

Science.gov (United States)

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

2014-08-15

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

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

Science.gov (United States)

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. Copyright 2010 Elsevier B.V. All rights reserved.

Survival, growth and reproduction of the imported ampullarid snail Marisa cornuarietis in Central Sudan.

Science.gov (United States)

Haridi, A A; el Safi, S H; Jobin, W R

1985-04-01

The ampullarid snail Marisa cornuarietis was imported to the Sudan in 1981 for evaluation as a biological control agent against the planorbid snails which transmit human schistosomes. In initial field studies in small protected ponds the generation time of M. cornuarietis was 4 months, as in Puerto Rico. The snails reached 4 cm in diameter after 1 year, compared to 3 cm in Puerto Rico. Their population density varied from 60 to 175 snails per metre of shore-line, compared to a similar pond in Puerto Rico where the stable density was about 115 snails per metre. The proportion surviving after 1 year was 0.03, less than the annual proportion surviving of 0.10 in Puerto Rico. Thus the preliminary results indicated that the ampullarid snails could establish strong populations in permanent habitats in central Sudan where there was adequate food, although it might take longer than it does in Puerto Rico.

Snail regulates p21WAF/CIP1 expression in cooperation with E2 A and Twist

International Nuclear Information System (INIS)

Takahashi, Eishi; Funato, Noriko; Higashihori, Norihisa; Hata, Yuiro; Gridley, Thomas; Nakamura, Masataka

2004-01-01

Snail, a zinc-finger transcriptional repressor, is essential for mesoderm and neural crest cell formation and epithelial-mesenchymal transition. The basic helix-loop-helix transcription factors E2A and Twist have been linked with Snail during embryonic development. In this study, we examined the role of Snail in cellular differentiation through regulation of p21 WAF/CIP1 expression. A reporter assay with the p21 promoter demonstrated that Snail inhibited expression of p21 induced by E2A. Co-expression of Snail with Twist showed additive inhibitory effects. Deletion mutants of the p21 promoter revealed that sequences between -270 and -264, which formed a complex with unidentified nuclear factor(s), were critical for E2A and Snail function. The E2A-dependent expression of the endogenous p21 gene was also inhibited by Snail

To reduce the global burden of human schistosomiasis, use ‘old fashioned’ snail control

Science.gov (United States)

Sokolow, Susanne H.; Wood, Chelsea L.; Jones, Isabel J.; Lafferty, Kevin D.; Kuris, Armand; Hsieh, Michael H.; De Leo, Giulio A.

2018-01-01

Control strategies to reduce human schistosomiasis have evolved from ‘snail picking’ campaigns, a century ago, to modern wide-scale human treatment campaigns, or preventive chemotherapy. Unfortunately, despite the rise in preventive chemotherapy campaigns, just as many people suffer from schistosomiasis today as they did 50 years ago. Snail control can complement preventive chemotherapy by reducing the risk of transmission from snails to humans. Here, we present ideas for modernizing and scaling up snail control, including spatiotemporal targeting, environmental diagnostics, better molluscicides, new technologies (e.g., gene drive), and ‘outside the box’ strategies such as natural enemies, traps, and repellants. We conclude that, to achieve the World Health Assembly’s stated goal to eliminate schistosomiasis, it is time to give snail control another look.

Impact and cost-effectiveness of snail control to achieve disease control targets for schistosomiasis.

Science.gov (United States)

Lo, Nathan C; Gurarie, David; Yoon, Nara; Coulibaly, Jean T; Bendavid, Eran; Andrews, Jason R; King, Charles H

2018-01-23

Schistosomiasis is a parasitic disease that affects over 240 million people globally. To improve population-level disease control, there is growing interest in adding chemical-based snail control interventions to interrupt the lifecycle of Schistosoma in its snail host to reduce parasite transmission. However, this approach is not widely implemented, and given environmental concerns, the optimal conditions for when snail control is appropriate are unclear. We assessed the potential impact and cost-effectiveness of various snail control strategies. We extended previously published dynamic, age-structured transmission and cost-effectiveness models to simulate mass drug administration (MDA) and focal snail control interventions against Schistosoma haematobium across a range of low-prevalence (5-20%) and high-prevalence (25-50%) rural Kenyan communities. We simulated strategies over a 10-year period of MDA targeting school children or entire communities, snail control, and combined strategies. We measured incremental cost-effectiveness in 2016 US dollars per disability-adjusted life year and defined a strategy as optimally cost-effective when maximizing health gains (averted disability-adjusted life years) with an incremental cost-effectiveness below a Kenya-specific economic threshold. In both low- and high-prevalence settings, community-wide MDA with additional snail control reduced total disability by an additional 40% compared with school-based MDA alone. The optimally cost-effective scenario included the addition of snail control to MDA in over 95% of simulations. These results support inclusion of snail control in global guidelines and national schistosomiasis control strategies for optimal disease control, especially in settings with high prevalence, "hot spots" of transmission, and noncompliance to MDA. Copyright © 2018 the Author(s). Published by PNAS.

Snail1 induces epithelial-to-mesenchymal transition and tumor initiating stem cell characteristics

International Nuclear Information System (INIS)

Dang, Hien; Ding, Wei; Emerson, Dow; Rountree, C Bart

2011-01-01

Tumor initiating stem-like cells (TISCs) are a subset of neoplastic cells that possess distinct survival mechanisms and self-renewal characteristics crucial for tumor maintenance and propagation. The induction of epithelial-mesenchymal-transition (EMT) by TGFβ has been recently linked to the acquisition of TISC characteristics in breast cancer. In HCC, a TISC and EMT phenotype correlates with a worse prognosis. In this work, our aim is to elucidate the underlying mechanism by which cells acquire tumor initiating characteristics after EMT. Gene and protein expression assays and Nanog-promoter luciferase reporter were utilized in epithelial and mesenchymal phenotype liver cancer cell lines. EMT was analyzed with migration/invasion assays. TISC characteristics were analyzed with tumor-sphere self-renewal and chemotherapy resistance assays. In vivo tumor assay was performed to investigate the role of Snail1 in tumor initiation. TGFβ induced EMT in epithelial cells through the up-regulation of Snail1 in Smad-dependent signaling. Mesenchymal liver cancer post-EMT demonstrates TISC characteristics such as tumor-sphere formation but are not resistant to cytotoxic therapy. The inhibition of Snail1 in mesenchymal cells results in decreased Nanog promoter luciferase activity and loss of self-renewal characteristics in vitro. These changes confirm the direct role of Snail1 in some TISC traits. In vivo, the down-regulation of Snail1 reduced tumor growth but was not sufficient to eliminate tumor initiation. In summary, TGFβ induces EMT and TISC characteristics through Snail1 and Nanog up-regulation. In mesenchymal cells post-EMT, Snail1 directly regulates Nanog expression, and loss of Snail1 regulates tumor growth without affecting tumor initiation

CRCP-Prey choice of corallivorous snails

Data.gov (United States)

National Oceanic and Atmospheric Administration, Department of Commerce — The snail, Coralliophila abbreviata, is a common generalist corallivore and can be a major contributor to Caribbean acroporid tissue mortality. Considering the...

Unpredictable responses of garden snail (Helix aspersa) populations to climate change

NARCIS (Netherlands)

Bezemer, T.M.; Knight, K.J.

2001-01-01

We studied the impact of climate change on the population dynamics of the garden snail (Helix aspersa) in the Ecotron controlled environment facility. The experimental series ran for three plant generations, allowing the snails to reproduce. We investigated the isolated and combined effects of

An analysis of suppressing migratory effect on human urinary bladder cancer cell line by silencing of snail-1.

Science.gov (United States)

Salehi, Shima; Mansoori, Behzad; Mohammadi, Ali; Davoudian, Sadaf; Musavi Shenas, Seyed Mohammad Hossein; Shajari, Neda; Majidi, Jafar; Baradaran, Behzad

2017-12-01

Snail-1 actively participates in tumor progression, invasion, and migration. Targeting snail-1 expression can suppress the EMT process in cancer. The aim of this study was to investigate the effect of snail1 silencing on urinary bladder cancer. Quantitative RT-PCR was used to detect snail-1 and other related metastatic genes expression following siRNA knockdown in urinary bladder cancer EJ-138 cells. The protein level of snail1 was assessed by Western blot. MTT and TUNEL assays were assessed to understand if snail-1 had survival effects on EJ-138 cells. Scratch wound healing assay measured cell motility effects after snail1 suppression. The significant silencing of snail-1 reached 60pmol siRNA in a 48-h post-transfection. The result of scratch assay showed that snail-1 silencing significantly decreased Vimentin, MMPs, and CXCR4 expression; however, expression of E-cadherin was induced. The cell death assay indicated that snail-1 played the crucial role in bladder cancer survival rate. These results propose that snail-1 plays a major role in the progression and migration of urinary bladder cancer, and can be a potential therapeutic target for target therapy of invasive urinary bladder cancer. Copyright © 2017 Elsevier Masson SAS. All rights reserved.

Changes in frequency of spontaneous oscillations in procerebrum correlate to behavioural choice in terrestrial snails

Directory of Open Access Journals (Sweden)

Elena Samarova

2009-08-01

Full Text Available The aim of our study was to understand functional significance of spontaneous oscillations of local field potential in the olfactory brain lobe of terrestrial snail, the procerebrum (PC. We compared changes in frequency of oscillations in semi-intact preparations from snails trained to percept the same conditioned odor as positive (associated with food reinforcement or negative (associated with noxious reinforcement. In vivo recordings in freely behaving naïve snails showed a significant decrease of spontaneous PC oscillations frequency during a stage of tentacle withdrawal to odor presentation. In in vitro preparations from naïve snails, a similar decrease in frequency of the PC oscillations to odor presentation was observed. Changes in frequency of the oscillations to cineole presentations in the “aversive” group of snails (demonstrating withdrawal were much more pronounced than in naïve snails. No significant difference in responses to 5 and 20% cineole was noted. Changes in the spontaneous oscillations frequency in the snails trained to respond with positive reaction (approach to cineole depended on the concentration of the applied odor, and these responses were qualitatively similar to responses of other groups during the first 10 s of responses to odor, but significantly different (increase in PC oscillations frequency from the responses of the aversively trained and naïve snails in the interval 11-30 s, which corresponds to the end of the tentacle withdrawal and timing of decision making (approach or escape in the free behaving snails. Obtained results suggest that frequency of the PC lobe spontaneous oscillations correlate to the choice of behavior in snails: withdrawal (decrease in frequency or approach (increase in frequency to the source of odor.

Calcareous forest seepages acting as biodiversity hotspots and refugia for woodland snail faunas

Science.gov (United States)

Horsák, Michal; Tajovská, Eva; Horsáková, Veronika

2017-07-01

Land-snail species richness has repeatedly been found to increase with the increasing site calcium content and humidity. These two factors, reported as the main drivers of land-snail assemblage diversity, are also among the main habitat characteristics of calcareous seepages. Here we explore local species richness and compositional variation of forest spring-fed patches (i.e. seepages), to test the hypothesis that these habitats might act as biodiversity hotspots and refugia of regional snail faunas. In contrast to treeless spring fens, only little is known about land snail faunas inhabiting forest seepages. Studying 25 isolated calcareous forest seepages, evenly distributed across the White Carpathians Protected Landscape Area (SE Czech Republic), we found that these sites, albeit spatially very limited, can harbour up to 66% of the shelled land-snail species known to occur in this well-explored protected area (in total 83 species). By comparing land snail assemblages of the studied seepages with those occurring in the woodland surroundings of each site as well as those previously sampled in 28 preserved forest sites within the study area, we found the seepages to be among the most species rich sites. Although the numbers of species did not statistically differ among these three systems, we found highly significant differences in species composition. Seepage faunas were composed of many species significantly associated with spring sites, in contrast to the assemblages of both surrounding and preserved forest sites. Our results highly support the hypothesis that calcareous forest seepages might serve as refugia and biodiversity hotspots of regional land snail faunas. Protection of these unique habitats challenges both conservation plans and forest management guidelines as they might act as sources for the recolonization and restoration of forest snail assemblages particularly in areas impoverished by harvesting and clearcutting.

[Effect of agroforestry model on inhibition of Oncomelania snails in plateau mountainous area of Yunnan Province].

Science.gov (United States)

Zhang, Chun-Hua; Tang, Guo-Yong; Liu, Fang-Yan; Li, Kun

2012-10-01

To evaluate the effect of agroforestry models on the inhibition of Oncomelania snails in the plateau mountainous area of Yunnan Province. The experimental field was established at Sanying Village of Eryuan County, Yunnan Province, where the "Flourishing Forest and Controlling Snails Project" was implemented. Different drought crops (alfalfa, vegetables, broad bean, garlic, lettuce, celery, green onions, and wheat) were intercropped under walnut forest in experimental groups, and the crops were not intercropped under walnut forest in a control group. The growth of forest, the change of snails and short-term income of residents were investigated. Agroforestry models promoted the forestry growth and effectively inhibited the growth of snails. There was a little snail in one of the experimental group that forest was intercropped with alfalfa (the occurrence rate of frames with living snails was 3.33%, the average density of living snails was 0.004/0.1 m2, and the declining rates were both 50.00%). The snails were not found in other intercropped models. The income of residents in the experimental groups increased (900-6 800 Yuan per year) compared with that in the control group. The model of walnut forest intercropped with crops not only has the obvious effect on inhibition of snails, but also has good economic and ecological benefits in the plateau mountainous area of Yunnan Province.

Preliminary Screening a Potential AChE Inhibitor in Thai Golden Shower (Leguminosae mimosoideae Extracts

Directory of Open Access Journals (Sweden)

Jakkaphun Nanuam

2013-07-01

Full Text Available Pesticides are used to control pests of agriculture products in many countries including Thailand. Since they can exert harmful effects not only on target pests but also on other useful organisms, alternative agents are investigated. We studied the capacity of the Thai golden shower (Leguminosae mimosoideae extracts (root and pod to inhibit acetyl cholinestarese (AChE in the golden apple snail (Pomacea canaliculata as a pest representative. The results showed that the percentage of AChE inhibition increased with increasing in exposure times. The inhibition expressed the same trend in both male and female apple snails. AChE inhibition was higher in extracts from root than from pod. Chromatography-Mass Spectrometer (GC-MS chromatograms demonstrated anthraquinone, an AChE inhibitor, in extracts of golden shower. Our data indicate that a potential AChE inhibitor tends to accumulate more in the root part than in the pod.

Threatened freshwater and terrestrial molluscs (Mollusca, Gastropoda et Bivalvia of Santa Catarina State, Southern Brazil: check list and evaluation of regional threats

Directory of Open Access Journals (Sweden)

2011-06-01

Full Text Available A total of nineteen continental native mollusc species are confirmed for the Santa Catarina State (SC(organized in ten Genera and seven Families, one aquatic Prosobranchia/Caenogastropoda (Ampullariidae,six Pulmonata terrestrial gastropods (one Ellobiidae, three Megalobulimidae and two micro-snails –Charopidae and Streptaxidae and twelve freshwater mussels (eight Mycetopodidae and four Hyriidae. Thesespecies are designated by the International Union for Conservation of the Nature – IUCN as follows: seven as"Vulnerable", six "In Danger" and six “Without Category Established”. The general regional threats that thesespecies are subjected to are briefly analyzed.

Pengaruh beberapa Jenis Ekstrak Tanaman sebagai Moluskisida Nabati terhadap Keong Mas (Pomacea canaliculata

Directory of Open Access Journals (Sweden)

Agus Kardinan

1997-12-01

Full Text Available Research has been carried out at the Pest and Disease Laboratory, Research Institute for Spices and Medicinal Crops, Bogar, in the 1997. Research consisted of three parts, those were; (I The toxicity of Dens elliptica, Blumea balsamifera, and methaldehyde, by determining the LC50 values, (2 Effect of the leaves of B.balsamifera, Euphorbia tirucalli and Tephrosia vogelii, (3 Effect of the most poisonous plant as ovicides. Result showed that D.elliptica was the most poisonous material to golden snail with its LC50 value was 400ppm, but it was still under the toxicity value of methaldehyde (11. 78 ppm. There was no significant difference among B.balsamifera, T.vogelii and E. canaliculata, but extract of B.balsarnifera tended to be better material among those plant extracts tested. The extract of D.elliptica did not affect egg hatching of golden snail.

Sensory mediation of memory blocking stressors in the pond snail Lymnaea stagnalis.

Science.gov (United States)

Dalesman, Sarah; Karnik, Vikram; Lukowiak, Ken

2011-08-01

The great pond snail, Lymnaea stagnalis, is commonly used as a model species to study how stress affects the ability to form long-term memory (LTM); however, we still have little information about how the snail senses stressful stimuli. The osphradium is an external sensory organ that demonstrates electrophysiological responses to a variety of external chemical stimuli. We examined the role, if any, played by the osphradium in sensing two environmental stressors, crowding and low environmental calcium, both known to block LTM in intact animals. We severed the osphradial nerve, blocking external sensory input from this organ to the central nervous system, and then exposed the snails to low environmental calcium or crowding stress to assess whether these stressors continued to block LTM formation. When exposed to low environmental calcium, snails with their osphradial nerve severed responded as if they were maintained in our standard calcium environment. That is, they did not respond to low calcium as a stressor blocking LTM; therefore, the osphradium plays a crucial role in mediating how snails respond to this stressor. However, following crowding, LTM formation was blocked in both control groups and snails that had the osphradial nerve severed, indicating that sensory information from the osphradium is not required to sense crowded conditions. Together these data show that two stressors that result in the same behavioural phenotype, blocking LTM formation, do so via two distinct sensory pathways.

Utilisation of Giant African snail (Achatina fulica meal as protein source for laying hens

Directory of Open Access Journals (Sweden)

Siaka Seriba Diarra

2015-05-01

Full Text Available A 12-week experiment was carried out to investigate the effects of substituting Giant African snail meal for fish meal in laying hens diet. Four diets were formulated to contain snail meal as replacement for fish meal at 0 (control, 33, 67 and 100 %. A total of 120 Shaver Brown pullets aged 18 weeks were allocated to the dietary treatments in a randomised design. Each treatment consisted of three replicates and ten birds per replicate. Feed intake increased only for the 33% treatment as compared to the 67% replacement diet but did not differ from the other treatments. There were no significant treatment effects on egg performance parameters observed (egg production, egg weight, total egg mass, feed conversion ratio and percent shell. The overall feed cost of egg production reduced on the snail mealbased diets. The organoleptic evaluation of boiled eggs revealed no difference between the treatments. Based on these results it was concluded that total replacement of fish meal with cooked snail meat meal does not compromise laying performance or egg quality. The substitution is beneficial in terms of production cost reduction and the reduction of snails will have a beneficial impact especially where these snails are a serious agricultural pest. The manual collection and processing of snails can also become a source of rural income.

effect of different prevein level on the land snail (achatina chatina ...

African Journals Online (AJOL)

RAJAH

The foot (edible portion), the shell and the visceral materials were weighed separately for each snail. .... Biometrics.11: 1-42. Ejidike, B. N., 2001. Comparative effect of supplemental and complete diets on the performance of. African giant land snail. Archachatina marginata). Proc. 26th Ann. Conf. Nig. Soc. for. Anim. Prod.

The butterflies and land snails of Ndere Island National Park, Kenya ...

African Journals Online (AJOL)

After a survey of Ndere Island National Park between October and November 2004, we recorded 18 species of butterflies and 3 species of land snails. Eurema brigitta brigitta was the most abundant butterfly whereas Thapsia karamwegasensis was the most abundant land snail. Majority of the butterfly species are found in ...

Tinjauan Keanekaragaman Moluska Air Tawar Di Beberapa Situ Di DAS Ciliwung - Cisadane [Study on the Freshwater Mollusc Diversity of the Small Lakes Along Ciliwung and Cisadane Rivers

OpenAIRE

Marwoto, Ristiyanti M; Isnaningsih, Nur R

2014-01-01

The freshwater molluscs (snails and bivalves) can be found in many type of water course either flowing or stagnant water. Some of them have survived living in bad condition such as polluted water. There are 199 situ (small lakes) in Jabodetabek (Jakarta, Bogor, Depok, Tangerang, Bekasi) have been reported but only 20 % were in good condition, even 12% have dissapeared that caused by silting up of the situ. The aim of the study was to evaluate the diversity of the molluscs as well as to know t...

Chlorophyllin Bait Formulation and Exposure to Different Spectrum of Visible Light on the Reproduction of Infected/Uninfected Snail Lymnaea acuminata

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Navneet Kumar

2016-01-01

Full Text Available 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.

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

International Nuclear Information System (INIS)

Shin, Na Ri; Lee, Jae Hyuk; Park, Do Youn; Jeong, Eun Hui; Choi, Chang In; Moon, Hyun Jung; Kwon, Chae Hwa; Chu, In Sun; Kim, Gwang Ha; Jeon, Tae Yong; Kim, Dae Hwan

2012-01-01

Epithelial–mesenchymal transition (EMT) plays a significant role in tumor progression and invasion. Snail is a known regulator of EMT in various malignant tumors. This study investigated the role of Snail in gastric cancer. We examined the effects of silenced or overexpressed Snail using lenti-viral constructs in gastric cancer cells. Immunohistochemical analysis of tissue microarrays from 314 patients with gastric adenocarcinoma (GC) was used to determine Snail’s clinicopathological and prognostic significance. Differential gene expression in 45 GC specimens with Snail overexpression was investigated using cDNA microarray analysis. Silencing of Snail by shRNA decreased invasion and migration in GC cell lines. Conversely, Snail overexpression increased invasion and migration of gastric cancer cells, in line with increased VEGF and MMP11. Snail overexpression (≥75% positive nuclear staining) was also significantly associated with tumor progression (P < 0.001), lymph node metastases (P = 0.002), lymphovascular invasion (P = 0.002), and perineural invasion (P = 0.002) in the 314 GC patients, and with shorter survival (P = 0.023). cDNA microarray analysis revealed 213 differentially expressed genes in GC tissues with Snail overexpression, including genes related to metastasis and invasion. Snail significantly affects invasiveness/migratory ability of GCs, and may also be used as a predictive biomarker for prognosis or aggressiveness of GCs

Heavy metal concentrations in a soil-plant-snail food chain along a terrestrial soil pollution gradient

Energy Technology Data Exchange (ETDEWEB)

Notten, M.J.M. [Institute of Ecological Science, Department of Systems Ecology, Vrije Universiteit Amsterdam, De Boelelaan 1085, 1081 HV, Amsterdam (Netherlands)]. E-mail: martje.notten@ecology.falw.vu.nl; Oosthoek, A.J.P. [Institute of Ecological Science, Department of Systems Ecology, Vrije Universiteit Amsterdam, De Boelelaan 1085, 1081 HV, Amsterdam (Netherlands); Rozema, J. [Institute of Ecological Science, Department of Systems Ecology, Vrije Universiteit Amsterdam, De Boelelaan 1085, 1081 HV, Amsterdam (Netherlands); Aerts, R. [Institute of Ecological Science, Department of Systems Ecology, Vrije Universiteit Amsterdam, De Boelelaan 1085, 1081 HV, Amsterdam (Netherlands)

2005-11-15

We investigated concentrations of Zn, Cu, Cd and Pb in the compartments of a soil-plant (Urtica dioica)-snail (Cepaea nemoralis) food chain in four polluted locations in the Biesbosch floodplains, the Netherlands, and two reference locations. Total soil metal concentrations in the polluted locations were 4-20 times higher than those in the reference locations. Positive relationships between the generally low leaf concentrations and the soil concentrations were found for Zn only (r {sup 2} = 0.20). Bioaccumulation of Zn, Cu and Cd was observed in the snail tissues. We found positive relationships between the snail and leaf concentrations for all metals (range r {sup 2} = 0.19-0.46). The relationships between soil and snail concentrations were also positive, except for Cu (range r {sup 2} = 0.15-0.33). These results suggest transfer of metals to C. nemoralis snails from U. dioica leaves and from the soil. Metal transfer from polluted leaves to C. nemoralis is more important than transfer from the soil. - Bioaccumulation and positive snail-leaf relationships suggest metal transfer from Urtica dioica leaves to Cepaea nemoralis snails.

Heavy metal concentrations in a soil-plant-snail food chain along a terrestrial soil pollution gradient

International Nuclear Information System (INIS)

Notten, M.J.M.; Oosthoek, A.J.P.; Rozema, J.; Aerts, R.

2005-01-01

We investigated concentrations of Zn, Cu, Cd and Pb in the compartments of a soil-plant (Urtica dioica)-snail (Cepaea nemoralis) food chain in four polluted locations in the Biesbosch floodplains, the Netherlands, and two reference locations. Total soil metal concentrations in the polluted locations were 4-20 times higher than those in the reference locations. Positive relationships between the generally low leaf concentrations and the soil concentrations were found for Zn only (r 2 = 0.20). Bioaccumulation of Zn, Cu and Cd was observed in the snail tissues. We found positive relationships between the snail and leaf concentrations for all metals (range r 2 = 0.19-0.46). The relationships between soil and snail concentrations were also positive, except for Cu (range r 2 = 0.15-0.33). These results suggest transfer of metals to C. nemoralis snails from U. dioica leaves and from the soil. Metal transfer from polluted leaves to C. nemoralis is more important than transfer from the soil. - Bioaccumulation and positive snail-leaf relationships suggest metal transfer from Urtica dioica leaves to Cepaea nemoralis snails

Effects of endocrine disruptors on prosobranch snails (Mollusca: Gastropoda) in the laboratory. Part I: Bisphenol A and octylphenol as xeno-estrogens.

Science.gov (United States)

Oehlmann, J; Schulte-Oehlmann, U; Tillmann, M; Markert, B

2000-12-01

The effects of suspected endocrine disrupting chemicals on freshwater and marine prosobranch species were analysed in laboratory experiments. In this first publication, the responses of the freshwater snail Marisa cornuarietis and of the marine prosobranch Nucella lapillus to the xeno-estrogenic model compounds bisphenol A (BPA) and octylphenol (OP) are presented at nominal concentration ranges between 1 and 100 micrograms/L. Marisa was exposed during 5 months using adult specimens and in a complete life-cycle test for 12 months. In both experiments, the xeno-estrogens induced a complex syndrome of alterations in female Marisa referred to as "superfemales" at the lowest concentrations. Affected specimens were characterised by the formation of additional female organs, an enlargement of the accessory pallial sex glands, gross malformations of the pallial oviduct section resulting in an increased female mortality, and a massive stimulation of oocyte and spawning mass production. The effects of BPA and OP were comparable at the same nominal concentrations. An exposure to OP resulted in inverted U-type concentration response relationships for egg and spawning mass production. Adult Nucella from the field were tested for three months in the laboratory. As in Marisa, superfemales with enlarged accessory pallial sex glands and an enhancement of oocyte production were observed. No oviduct malformations were found probably due to species differences in the gross anatomical structure of the pallial oviduct. A lower percentage of exposed specimens had ripe sperm stored in their vesicula seminalis and additionally male Nucella exhibited a reduced length of penis and prostate gland when compared to the control. Because statistically significant effects were observed at the lowest nominal test concentrations (1 microgram BPA or OP/L), it can be assumed that even lower concentrations may have a negative impact on the snails. The results show that prosobranchs are sensitive to

Potentiation of zinc stress caused by parastic infection of snails

Energy Technology Data Exchange (ETDEWEB)

Guth, D.J. (Univ. of Michigan, Flint); Blankespoor, H.D.; Cairns, J. Jr.

1977-09-08

The purpose of this experiment was to determine the effects of parasitism (Schistosomatium douthitti Price and Trichobilharzia sp.) on the tolerance of snails Lymnaea stagnalis (L.) to acutely lethal concentrations of zinc. Significant reduction in tolerance occurred for snails with patent infections at 24 and 75 ppM of Zn/sup + +/. At two selected prepatent levels of parasite development, significant differences occurred at the higher concentration only.

The transcription factor snail controls epithelial-mesenchymal transitions by repressing E-cadherin expression

DEFF Research Database (Denmark)

Cano, A; Pérez-Moreno, M A; Rodrigo, I

2000-01-01

The Snail family of transcription factors has previously been implicated in the differentiation of epithelial cells into mesenchymal cells (epithelial-mesenchymal transitions) during embryonic development. Epithelial-mesenchymal transitions are also determinants of the progression of carcinomas......, occurring concomitantly with the cellular acquisition of migratory properties following downregulation of expression of the adhesion protein E-cadherin. Here we show that mouse Snail is a strong repressor of transcription of the E-cadherin gene. Epithelial cells that ectopically express Snail adopt...

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

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Nica Dragos V

2012-06-01

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

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

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Suzanne M. F. El-Nassery

2013-01-01

Full Text Available 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.

Effect of radiation on Lymnnea auricularia rubiginosa snails

International Nuclear Information System (INIS)

Cruz, B. de la; Yumul, B.V.; Anden, A.; Perpuse, W.G.

1976-03-01

As a means of checking the spread of fascioliasis, the intermediate host of F. hepatica and F. gigantica which is the Lumnea auricularia rubiginosa is exposed to different doses of radioisotopes. Radioisotopes used were 32 P, 3 H-thymidine, and 137 Cs. Findings show that at different concentration and doses of radioisotopes, there is a reduced viability and increase mortality in the eggs laid by the parent snails exposed to radiation. The effects on the development of irradiated eggs are also being studied as well as the effects of irradiation on the reproductive apparatus of the snails

A population growth trend analysis for Neotricula aperta, the snail intermediate host of Schistosoma mekongi, after construction of the Pak-Mun dam.

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Stephen W Attwood

2013-11-01

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

Distribution and habitats of the snail Lymnaea truncatula, intermediate host of the liver fluke Fasciola hepatica, in South Africa

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K.N. de Kock

2003-07-01

Full Text Available This paper focuses on the geographical distribution and habitats of Lymnaea truncatula, the intermediate, snail host of the liver fluke, Fasciola hepatica, as reflected by the 723 samples in the database of the National Freshwater Snail Collection, Potchefstroom, South Africa. The 221 different loci (1/16-degree squares on record reflect an extensive but discontinuous distribution, except in Lesotho and in parts of the Mpumalanga, Gauteng and North West provinces of South Africa. Although recorded from 12 different types of waterbody, it was mostly (42.0 % recovered from swamps. Most samples (45.8 % were collected in habitats with slow-flowing water. A muddy substratum was recorded for 62.5 % of the samples. Most samples (86.3 % were collected in habitats with a mean annual air temperature of 10-20 o C, and more than 69 % came from localities with a mean annual rainfall of 600-900mm. An integrated decision tree constructed from the data indicated that temperature and types of waterbody play a decisive role in determining the presence of L. truncatula in a given area. A temperature index calculated for all mollusc species ranked L. truncatula second in a total of 53 species according to its association with low temperatures. It remains to be established whether its distribution is indeed discontinuous, and whether its preference for a particular habitat, amphibious habits and ability to aestivate could have resulted in some populations having been overlooked during surveys.

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

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T. D. Mangal

2010-01-01

Full Text Available 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.

Effects of Deepwater Horizon Oil on the Movement and Survival of Marsh Periwinkle Snails (Littoraria irrorata).

Science.gov (United States)

Garner, T Ross; Hart, Michael A; Sweet, Lauren E; Bagheri, Hanna T J; Morris, Jeff; Stoeckel, James A; Roberts, Aaron P

2017-08-01

The Deepwater Horizon (DWH) oil spill resulted in the release of millions of barrels of oil into the Gulf of Mexico, and some marsh shorelines experienced heavy oiling including vegetation laid over under the weight of oil. Periwinkle snails (Littoraria irrorata) are a critical component of these impacted habitats, and population declines following oil spills, including DWH, have been documented. This study determined the effects of oil on marsh periwinkle movement and survivorship following exposure to oil. Snails were placed in chambers containing either unoiled or oiled laid over vegetation to represent a heavily impacted marsh habitat, with unoiled vertical structure at one end. In the first movement assay, snail movement to standing unoiled vegetation was significantly lower in oiled chambers (oil thickness ≈ 1 cm) compared to unoiled chambers, as the majority (∼75%) of snails in oiled habitats never reached standing unoiled vegetation after 72 h. In a second movement assay, there was no snail movement standing unoiled structure in chambers with oil thicknesses of 0.1 and 0.5 cm, while 73% of snails moved in unoiled chambers after 4h. A toxicity assay was then conducted by exposing snails to oil coated Spartina stems in chambers for periods up to 72 h, and mortality was monitored for 7 days post exposure. Snail survival decreased with increasing exposure time, and significant mortality (∼35%) was observed following an oil exposure of less than 24 h. Here, we have shown that oil impeded snail movement to clean habitat over a short distance and resulted in oil-exposure times that decreased survival. Taken together, along with declines documented by others in field surveys, these results suggest that marsh periwinkle snails may have been adversely affected following exposure to DWH oil.

Impact and cost-effectiveness of snail control to achieve disease control targets for schistosomiasis

OpenAIRE

Lo, Nathan C.; Gurarie, David; Yoon, Nara; Coulibaly, Jean T.; Bendavid, Eran; Andrews, Jason R.; King, Charles H.

2018-01-01

Schistosomiasis is a parasitic disease that affects over 240 million people globally. To improve population-level disease control, there is growing interest in adding chemical-based snail control interventions to interrupt the lifecycle of Schistosoma in its snail host to reduce parasite transmission. However, this approach is not widely implemented, and given environmental concerns, the optimal conditions for when snail control is appropriate are unclear. We assessed the potential impact and...

Release of lungworm larvae from snails in the environment: potential for alternative transmission pathways.

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Alessio Giannelli

2015-04-01

Full Text Available 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.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.Results of this study

Snail regulates cell survival and inhibits cellular senescence in human metastatic prostate cancer cell lines.

Science.gov (United States)

Emadi Baygi, Modjtaba; Soheili, Zahra Soheila; Schmitz, Ingo; Sameie, Shahram; Schulz, Wolfgang A

2010-12-01

The epithelial-mesenchymal transition (EMT) is regarded as an important step in cancer metastasis. Snail, a master regulator of EMT, has been recently proposed to act additionally as a cell survival factor and inducer of motility. We have investigated the function of Snail (SNAI1) in prostate cancer cells by downregulating its expression via short (21-mer) interfering RNA (siRNA) and measuring the consequences on EMT markers, cell viability, death, cell cycle, senescence, attachment, and invasivity. Of eight carcinoma cell lines, the prostate carcinoma cell lines LNCaP and PC-3 showed the highest and moderate expression of SNAI1 mRNA, respectively, as measured by quantitative RT-PCR. Long-term knockdown of Snail induced a severe decline in cell numbers in LNCaP and PC-3 and caspase activity was accordingly enhanced in both cell lines. In addition, suppression of Snail expression induced senescence in LNCaP cells. SNAI1-siRNA-treated cells did not tolerate detachment from the extracellular matrix, probably due to downregulation of integrin α6. Expression of E-cadherin, vimentin, and fibronectin was also affected. Invasiveness of PC-3 cells was not significantly diminished by Snail knockdown. Our data suggest that Snail acts primarily as a survival factor and inhibitor of cellular senescence in prostate cancer cell lines. We therefore propose that Snail can act as early driver of prostate cancer progression.

Are sick individuals weak competitors? Competitive ability of snails parasitized by a gigantism-inducing trematode.

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Otto Seppälä

Full Text Available 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.

Effects of 5-HT and insulin on learning and memory formation in food-deprived snails.

Science.gov (United States)

Aonuma, Hitoshi; Totani, Yuki; Kaneda, Mugiho; Nakamura, Ryota; Watanabe, Takayuki; Hatakeyama, Dai; Dyakonova, Varvara E; Lukowiak, Ken; Ito, Etsuro

2018-02-01

The pond snail Lymnaea stagnalis learns conditioned taste aversion (CTA) and consolidates it into long-term memory (LTM). How well they learn and form memory depends on the degree of food deprivation. Serotonin (5-HT) plays an important role in mediating feeding, and insulin enhances the memory consolidation process following CTA training. However, the relationship between these two signaling pathways has not been addressed. We measured the 5-HT content in the central nervous system (CNS) of snails subjected to different durations of food deprivation. One-day food-deprived snails, which exhibit the best learning and memory, had the lowest 5-HT content in the CNS, whereas 5-day food-deprived snails, which do not learn, had a high 5-HT content. Immersing 1-day food-deprived snails in 5-HT impaired learning and memory by causing an increase in 5-HT content, and that the injection of insulin into these snails reversed this impairment. We conclude that insulin rescues the CTA deficit and this may be due to a decrease in the 5-HT content in the CNS of Lymnaea. Copyright © 2018 Elsevier Inc. All rights reserved.

Perspectives on land snails - sampling strategies for isotopic analyses

Science.gov (United States)

Kwiecien, Ola; Kalinowski, Annika; Kamp, Jessica; Pellmann, Anna

2017-04-01

Since the seminal works of Goodfriend (1992), several substantial studies confirmed a relation between the isotopic composition of land snail shells (d18O, d13C) and environmental parameters like precipitation amount, moisture source, temperature and vegetation type. This relation, however, is not straightforward and site dependent. The choice of sampling strategy (discrete or bulk sampling) and cleaning procedure (several methods can be used, but comparison of their effects in an individual shell has yet not been achieved) further complicate the shell analysis. The advantage of using snail shells as environmental archive lies in the snails' limited mobility, and therefore an intrinsic aptitude of recording local and site-specific conditions. Also, snail shells are often found at dated archaeological sites. An obvious drawback is that shell assemblages rarely make up a continuous record, and a single shell is only a snapshot of the environmental setting at a given time. Shells from archaeological sites might represent a dietary component and cooking would presumably alter the isotopic signature of aragonite material. Consequently, a proper sampling strategy is of great importance and should be adjusted to the scientific question. Here, we compare and contrast different sampling approaches using modern shells collected in Morocco, Spain and Germany. The bulk shell approach (fine-ground material) yields information on mean environmental parameters within the life span of analyzed individuals. However, despite homogenization, replicate measurements of bulk shell material returned results with a variability greater than analytical precision (up to 2‰ for d18O, and up to 1‰ for d13C), calling for caution analyzing only single individuals. Horizontal high-resolution sampling (single drill holes along growth lines) provides insights into the amplitude of seasonal variability, while vertical high-resolution sampling (multiple drill holes along the same growth line

4 Prevalence of Snail.cdr

African Journals Online (AJOL)

Administrator

Kpong head pond is a lake system that was created just below the Kpong dam. The high occurrence of B. trunctus found by this study, coupled with the intense human activity that occurs at the banks of the head pond, indicates that an active transmission of S. haematobiumparasite occurs in the area. The snails were ...

Distribution and habitats of Lymnaea natalensis, snail intermediate host of the liver fluke Fasciola gigantica, in South Africa

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Editorial Office

2001-09-01

Full Text Available This paper focuses on the geographical distribution and the habitats of Lymnaea natalensis, the snail intermediate host of the liver fluke, Fasciola gigantica, as reflected by the collection sites of its 4 552 samples currently on record in the National Freshwater Snail Collection (NFSC of South Africa. Although this species was represented in a variety of waterbodies, the majority of samples(±70%came from rivers, brooks and dams and in 70.8% of the cases the water was described as permanent and in 71.8% as slow flowing or standing. The results of life-table studies conducted by various authors indicated that temperature should be a relatively unimportant factor in determining its geographical distribution, but that the availability of permanent water should be decisive for its presence in a given habitat. These results are in agreement with the finding that only 7.5% of the samples of this species in the NFSC were collected in habitats which were described as seasonal. Furthermore, it gives a logical explanation for the sporadic occurrence, or total absence of this species in the more arid regions of South Africa. Water impoundments and irrigation networks contribute to a large extent towards creating perennial habitats which would be suitable for L. natalensis. As intermediate host for one of the liver fluke species which already is an economic factor in South Africa, this certainly is an aspect which ought to be reckoned within the planning and construction of new irrigation schemes.

Impairment of context memory by β-amyloid peptide in terrestrial snail

Directory of Open Access Journals (Sweden)

2008-09-01

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

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

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

1990-01-01

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

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

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Gutiérrez Alfredo

2002-01-01

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

Effects of Bt-maize material on the life cycle of the land snail Cantareus aspersus

DEFF Research Database (Denmark)

Kramarz, Paulina; de Vaufleury, Annette; Gimbert, Frédéric

2009-01-01

). For snails not previously exposed to Bt material, hatchability of eggs was similar in the soils tested. The outcome of the experiments indicates that, in growing snails, long-term exposure is needed to reveal an effect of Bt-maize. The hazard analysis of Bt-maize which we performed, based on a worst......Insect resistant Bt-maize (MON 810) expresses active Cry1Ab endotoxin derived from Bacillus thuringiensis (Bt). Snails constitute non-target soil species potentially exposed to Bt-toxin through consumption of plant material and soil in fields where transgenic plants have been grown. We studied...... the effect of the Cry1Ab toxin on survival, growth and egg hatchability of the snail Cantareus aspersus. From the age of 4 to 88 weeks, snails were fed either powdered Bt-maize or non-Bt-maize and exposed to soil samples collected after harvesting either the Bt-maize or non-Bt-maize. We applied four...

CRCP-Acropora palmata snail corallivore removal evaluation

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National Oceanic and Atmospheric Administration, Department of Commerce — Corallivorous snail feeding scars are a common source of tissue loss for the threatened coral Acropora palmata, accounting for roughly one quarter of tissue loss in...

Impacts of Thermal Treatments on Major and Minor Allergens of Sea Snail, Cerithidea obtusa (Obtuse Horn Shell)

OpenAIRE

Rosmilah Misnan; Norazlin Salahudin Abd Aziz; Zailatul Hani Mohamad Yadzir; Faizal Bakhtiar; Noormalin Abdullah; Shahnaz Murad

2016-01-01

Snail is one of the worst causes of food allergy. Thus, the aim of this study was to identify the major and minor allergens of the local marine snail (Cerithidea obtusa) and subsequently to investigate the impacts of heat treatment on the IgE-binding activity of snail allergens. Proteins from raw and heat-treated snails (boiled, roasted and fried) were extracted and then resolved by sodium dodecyl sulphate-polyacrylamide gel electrophoresis (SDS-PAGE). Immunoblotting of all extracts were then...

Host ploidy, parasitism and immune defence in a coevolutionary snail-trematode system.

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Osnas, E E; Lively, C M

2006-01-01

We studied the role of host ploidy and parasite exposure on immune defence allocation in a snail-trematode system (Potamopyrgus antipodarum-Microphallus sp.). In the field, haemocyte (the defence cell) concentration was lowest in deep-water habitats where infection is relatively low and highest in shallow-water habitats where infection is common. Because the frequency of asexual triploid snails is positively correlated with depth, we also experimentally studied the role of ploidy by exposing both diploid sexual and triploid asexual snails to Microphallus eggs. We found that triploid snails had lower haemocyte concentrations than did diploids in both parasite-addition and parasite-free treatments. We also found that both triploids and diploids increased their numbers of large granular haemocytes at similar rates after parasite exposure. Because triploid P. antipodarum have been shown to be more resistant to allopatric parasites than diploids, the current results suggest that the increased resistance of triploids is because of intrinsic genetic properties rather than to greater allocation to defence cells. This finding is consistent with recent theory on the advantages of increased ploidy for hosts combating coevolving parasites.

Deposition of strontium and calcium in snail shell

Energy Technology Data Exchange (ETDEWEB)

Rosenthal, Jr, G M; Nelson, D J; Gardiner, D A

1965-07-03

The relative effects of strontium and calcium concentrations in the environment on their uptake and incorporation into snail shell were investigated. /sup 45/Ca and /sup 85/Sr were used as tracers and specific activities were used to determine deposition. Data are presented in tables and graphs. Deposition of both calcium and strontium in the snail shell depended primarily on the respective concentrations of these elements in the immediate environment. A slight effect of strontium on calcium deposition was observed. There was found to be a minimum strontium deposition for various combinations of strontium and calcium in the environment. It was concluded that strontium uptake is more closely associated with environmental strontium concentrations than with calcium concentrations.

Tropomyosin or not tropomyosin, what is the relevant allergen in house dust mite and snail cross allergies?

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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.

Prevalence of Haplorchis taichui in Field-Collected Snails: A Molecular Approach

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Chontananarth, Thapana

2010-01-01

The prevalence of the cercarial stage of an intestinal trematode, Haplorchis taichui, in thiarid snails (Gastropoda: Thiaridae) was investigated using light microscope and species-specific PCR procedures. A total of 988 snails were collected from Mae Taeng district, Chiang Mai province, northern Thailand, which comprised of 3 species; Melanoides tuberculata, Tarebia granifera, and Thiara scabra. The overall prevalence of pleurolophocercous cercariae was 21.7% as determined by the morphology. For genetic detection of H. taichui infection in snails, 2 primers Hapt_F (5'-GGCCAACGCAATCGTCATCC-3') and Hapt_R (5'-GCGTCGGGTTTCAGACATGG-3'), were used. The genomic DNA of H. taichui, which was used as a positive control, gave an amplification of the 256 bp fragment. The overall prevalence of H. taichui from specific PCR was 9.7%. The proportion of H. taichui among the pleurolophocercous cercariae in this study was 44.9%. PMID:21234240

Possible control of introduced giant African land snails (Achatina spp. by the reintroduced endemic skink Leiolopisma telfairii, Ile aux Aigrettes, Mauritius

Directory of Open Access Journals (Sweden)

Jamie A. COPSEY

2011-01-01

Full Text Available The giant African land snail (Achatina fulica is one of the world’s worst invasive species, out‐competing endemic snails, consuming native vegetation and potentially altering nutrient cycles. Attempts to eradicate the snail from islands have only been successful with incipient populations. We present correlative evidence that native island predators may act as an effective control agent for the snail. In 2000 a population of between 37,300 and 45,100 African land snails was estimated on the 26ha nature reserve island of Ile aux Aigrette, Mauritius. Between 2006 and 2007, 260 endemic Telfair’s skink Leiolopisma telfairii were reintroduced to the reserve. Snail population surveys in 2008 and 2009 showed that the introduced snail population had declined to 5,569 (± 3,630 and 6,871 (±5,379, respectively. Previous studies showed that the introduced snails were selective over other invertebrate prey items. We suggest that predation by the endemic skink has been an important causal factor behind the snail population decline.

Hormone-like peptides in the venoms of marine cone snails

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Robinson, Samuel D.; Li, Qing; Bandyopadhyay, Pradip K.; Gajewiak, Joanna; Yandell, Mark; Papenfuss, Anthony T.; Purcell, Anthony W.; Norton, Raymond S.; Safavi-Hemami, Helena

2015-01-01

The venoms of cone snails (genus Conus) are remarkably complex, consisting of hundreds of typically short, disulfide-rich peptides termed conotoxins. These peptides have diverse pharmacological targets, with injection of venom eliciting a range of physiological responses, including sedation, paralysis and sensory overload. Most conotoxins target the prey’s nervous system but evidence of venom peptides targeting neuroendocrine processes is emerging. Examples include vasopressin, RFamide neuropeptides and recently also insulin. To investigate the diversity of hormone/neuropeptide-like molecules in the venoms of cone snails we systematically mined the venom gland transcriptomes of several cone snail species and examined secreted venom peptides in dissected and injected venom of the Australian cone snail Conus victoriae. Using this approach we identified several novel hormone/neuropeptide-like toxins, including peptides similar to the bee brain hormone prohormone-4, the mollusc ganglia neuropeptide elevenin, and thyrostimulin, a member of the glycoprotein hormone family, and confirmed the presence of insulin. We confirmed that at least two of these peptides are not only expressed in the venom gland but also form part of the injected venom cocktail, unambiguously demonstrating their role in envenomation. Our findings suggest that hormone/neuropeptide-like toxins are a diverse and integral part of the complex envenomation strategy of Conus. Exploration of this group of venom components offers an exciting new avenue for the discovery of novel pharmacological tools and drug candidates, complementary to conotoxins. PMID:26301480

Hormone-like peptides in the venoms of marine cone snails.

Science.gov (United States)

Robinson, Samuel D; Li, Qing; Bandyopadhyay, Pradip K; Gajewiak, Joanna; Yandell, Mark; Papenfuss, Anthony T; Purcell, Anthony W; Norton, Raymond S; Safavi-Hemami, Helena

2017-04-01

The venoms of cone snails (genus Conus) are remarkably complex, consisting of hundreds of typically short, disulfide-rich peptides termed conotoxins. These peptides have diverse pharmacological targets, with injection of venom eliciting a range of physiological responses, including sedation, paralysis and sensory overload. Most conotoxins target the prey's nervous system but evidence of venom peptides targeting neuroendocrine processes is emerging. Examples include vasopressin, RFamide neuropeptides and recently also insulin. To investigate the diversity of hormone/neuropeptide-like molecules in the venoms of cone snails we systematically mined the venom gland transcriptomes of several cone snail species and examined secreted venom peptides in dissected and injected venom of the Australian cone snail Conus victoriae. Using this approach we identified several novel hormone/neuropeptide-like toxins, including peptides similar to the bee brain hormone prohormone-4, the mollusc ganglia neuropeptide elevenin, and thyrostimulin, a member of the glycoprotein hormone family, and confirmed the presence of insulin. We confirmed that at least two of these peptides are not only expressed in the venom gland but also form part of the injected venom cocktail, unambiguously demonstrating their role in envenomation. Our findings suggest that hormone/neuropeptide-like toxins are a diverse and integral part of the complex envenomation strategy of Conus. Exploration of this group of venom components offers an exciting new avenue for the discovery of novel pharmacological tools and drug candidates, complementary to conotoxins. Copyright © 2015 Elsevier Inc. All rights reserved.

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

Science.gov (United States)

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

2010-12-01

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

Identification of characteristic aroma compounds in raw and thermally processed African giant snail (Achatina fulica).

Science.gov (United States)

Lasekan, Ola; Muniady, Megala; Lin, Mee; Dabaj, Fatma

2018-04-24

Food flavor appreciation is one of the first signals along with food appearance and texture encountered by consumers during eating of food. Also, it is well known that flavor can strongly influence consumer's acceptability judgment. The increase in the consumption of snail meat across the world calls for the need to research into the aroma compounds responsible for the distinctive aroma notes of processed snail meat. The odorants responsible for the unique aroma notes in thermally processed giant African snail meats were evaluated by means of aroma extract dilution analysis (AEDA), gas chromatography-olfactometry (GC-O) and odor activity values (OAVs) respectively. Results revealed significant differences in the aroma profiles of the raw and thermally processed snail meats. Whilst the aroma profile of the raw snail meat was dominated with the floral-like β-ionone and β-iso-methyl ionone, sweaty/cheesy-like butanoic acid, and the mushroom-like 1-octen-3-one, the boiled and fried samples were dominated with the thermally generated odorants like 2-methylpyrazine, 2,5-dimethylpyrazine, 2-acetylthiazole and 2-acetylpyridine. Finally, results have shown that sotolon, 2-acetyl-1-pyrroline, 2-furanmethanethiol, 2-methylbutanal, 1-octen-3-one, octanal, furanone, 2-methoxyphenol, 2-acetylpyridine, 2-acetylthiazole, and 2-methylpyrazine contributed to the overall aroma of the thermally processed snail meat.

Role of the lymnaeid snail Pseudosuccinea columella in the transmission of the liver fluke Fasciola hepatica in Egypt.

Science.gov (United States)

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

2015-11-01

Experimental infections of three Egyptian Pseudosuccinea columella populations with sympatric miracidia of Fasciola sp., coming from cattle- or sheep-collected eggs, were carried out to determine the capacity of this lymnaeid to support larval development of the parasite. Using microsatellite markers, the isolates of Egyptian miracidia were identified as Fasciola hepatica. Apart from being independent of snail origin, prevalences ranging from 60.4 to 75.5% in snails infected with five miracidia of F. hepatica were significantly higher than values of 30.4 to 42.2% in snails with bi-miracidial infections. The number of metacercariae ranged from 243 to 472 per cercarial-shedding snail and was independent of snail origin, parasite origin and miracidial dose used for infection. If P. columella was subjected to two successive bi-miracidial infections with F. hepatica, prevalence of infection was 63.3%, with a mean of 311 metacercariae per snail. These values were clearly greater than those already reported for Radix natalensis infected with the same parasite and the same protocol. Successful experimental infection of P. columella with F. hepatica suggests that this lymnaeid snail is an important intermediate host for the transmission of fascioliasis in Egypt.

Endogenous growth factor stimulation of hemocyte proliferation induces resistance to Schistosoma mansoni challenge in the snail host.

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Pila, Emmanuel A; Gordy, Michelle A; Phillips, Valerie K; Kabore, Alethe L; Rudko, Sydney P; Hanington, Patrick C

2016-05-10

Digenean trematodes are a large, complex group of parasitic flatworms that infect an incredible diversity of organisms, including humans. Larval development of most digeneans takes place within a snail (Gastropoda). Compatibility between snails and digeneans is often very specific, such that suitable snail hosts define the geographical ranges of diseases caused by these worms. The immune cells (hemocytes) of a snail are sentinels that act as a crucial barrier to infection by larval digeneans. Hemocytes coordinate a robust and specific immunological response, participating directly in parasite killing by encapsulating and clearing the infection. Hemocyte proliferation and differentiation are influenced by unknown digenean-specific exogenous factors. However, we know nothing about the endogenous control of hemocyte development in any gastropod model. Here, we identify and functionally characterize a progranulin [Biomphalaria glabrata granulin (BgGRN)] from the snail B. glabrata, a natural host for the human blood fluke Schistosoma mansoni Granulins are growth factors that drive proliferation of immune cells in organisms, spanning the animal kingdom. We demonstrate that BgGRN induces proliferation of B. glabrata hemocytes, and specifically drives the production of an adherent hemocyte subset that participates centrally in the anti-digenean defense response. Additionally, we demonstrate that susceptible B. glabrata snails can be made resistant to infection with S. mansoni by first inducing hemocyte proliferation with BgGRN. This marks the functional characterization of an endogenous growth factor of a gastropod mollusc, and provides direct evidence of gain of resistance in a snail-digenean infection model using a defined factor to induce snail resistance to infection.

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

Science.gov (United States)

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.

Medium rare or well done - how would you like your snail? Influence of cooking practices on the isotopic composition of land snails' shells

Science.gov (United States)

Kwiecien, O.; Breitenbach, S. F. M.

2017-12-01

Since the seminal work of Goodfriend (1992, EPSL 11), several studies confirmed a relation between the isotopic composition (δ18O, δ13C) of land snail shell carbonate, and environmental parameters like precipitation amount, moisture source, temperature and vegetation. This relation, however, is not straightforward and, importantly, site dependent. The choice of sampling strategy (discrete or bulk sampling), cleaning procedure, and/or pre-depositional history further complicate the shell analysis. The advantage of using snail shells as environmental archive lies in their limited mobility, and thus an intrinsic aptitude of recording local and site-specific conditions. However, snail shells found at archaeological sites, even if of local origin, often represent a dietary component and boiling/roasting could potentially alter the isotopic signature of aragonite material. While thermal processing affects the clumped isotope composition of carbonates, its influence on traditional isotopes is still debated (Ritter et al. 2017, Sedimentology; Müller et al. 2017, Scientific Reports). Consequently, a proper sampling strategy is of great importance and should be chosen according to scientific question. Horizontal high-resolution shell sampling (drill holes along growth axis, across growth lines) provides insights into the amplitude of seasonal variability, while vertical high-resolution sampling (multiple drill holes along the same growth line) produces reproducible results. We took advantage of this reproducibility and, on a yet unprecedented scale, experimentally and sequentially tested the influence of boiling on the δ18O and δ13C signature of shells of modern Helix pomatia. Our results challenge recent reports on alteration due to boiling (Müller et al., 2017, Scientific Reports) and support uncompromised application of snail shells from archeological sites for paleoenvironmental reconstructions.

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

Science.gov (United States)

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

2012-12-01

The gastrointestinal (GI) tract of invasive land snail Achatina fulica is known to harbor metabolically active bacterial communities. In this study, we assessed the bacterial diversity in the different regions of GI tract of Giant African snail, A. fulica by culture-independent and culture-dependent methods. Five 16S rRNA gene libraries from different regions of GI tract of active snails indicated that sequences affiliated to phylum 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. © 2012 The Authors. Published by Blackwell Publishing Ltd.

Defense response of susceptible and resistant Biomphalaria alexandrina snails against Schistosoma mansoni infection

Directory of Open Access Journals (Sweden)

Iman F. Abou-El-Naga

2012-09-01

Full Text Available In Egypt, Biomphalaria alexandrina is the intermediate host for Schistosoma mansoni. The fates of Schistosoma miracidia in the snails varies between different species of Biomphalaria. The internal defense system is one of the factors that influence the susceptibility pattern of the snails. The interaction between Biomphalaria snails and S. mansoni needs to be identified for each species, and even between the members of the same species with different degrees of susceptibility. In the present study, the first generation of susceptible and resistant parents of B. alexandrina was examined histologically at the 30th day post exposure. The study includes the characterization of the immune response, as expressed by tissue reactions, of susceptible and resistant B. alexandrina snails against S. mansoni. It was also designed to determine the impact of the resistance increase in parent snails, on the mechanisms of interaction of their offspring against infection. The results showed that the infection rate of the offspring from the susceptible parents was 92%. No susceptible offspring was produced from the resistant parents. When the parents were of equal number of susceptible and resistant snails, they gave an offspring with an infection rate of 20%. Susceptible snails that had susceptible parents showed a higher degree of susceptibility than those that had both susceptible and resistant parents. A common feature of the resistant snails was the absence of any viable parasites. The tissue reactions of the resistant snails having only resistant parents occurred at the site of miracidial penetration. In resistant snails for which susceptible ones were included in their parents, the reactions occurred in the deep tissues. These results characterized the immune response of B. alexandrina snails against Schistosoma infection which was found to occur by two different mechanisms. One type of defense occurs in highly resistant snails, and employs direct

The use of ionizing radiation in the control of Oncomelania quadrasi snails

International Nuclear Information System (INIS)

Cruz, B. de la; Asis, A.V.; Pagulayan, P.; Payongayong, A.; Pineda, R.

1983-01-01

Schistosomiasis is still an endemic disease affecting mostly farmers. One way of checking the spread of the disease is to eradicate the intermediate host of parasite. Previous reports indicate that application of nuclear techniques could be a viable tool in the control of parasites of medical importance. To determine whether ionizing radiation could be a useful tool in the control of Oncomelania quadrasi, which is the vector host of Schistosoma japonicum. Attempts have been made to determine whether genetic effects on irradiated male snails can be transmitted to their progenies. These deleterious effects could be either short life span or defective reproductive capacity of the progenies. Attemps were also made to determine whether introduction of irradiated male snails in a given population could reduce the snail density. (author)

Soil parameters are key factors to predict metal bioavailability to snails based on chemical extractant data

International Nuclear Information System (INIS)

Pauget, B.; Gimbert, F.; Scheifler, R.; Coeurdassier, M.; Vaufleury, A. de

2012-01-01

Although soil characteristics modulate metal mobility and bioavailability to organisms, they are often ignored in the risk assessment of metal transfer. This paper aims to determine the ability of chemical methods to assess and predict cadmium (Cd), lead (Pb) and zinc (Zn) environmental bioavailability to the land snail Cantareus aspersus. Snails were exposed in the laboratory for 28 days to 17 soils from around a former smelter. The soils were selected for their range of pH, organic matter, clay content, and Cd, Pb and Zn concentrations. The influence of soil properties on environmental availability (estimated using HF-HClO 4 , EDTA, CaCl 2 , NH 4 NO 3 , NaNO 3 , free ion activity and total dissolved metal concentration in soil solution) and on environmental bioavailability (modelled using accumulation kinetics) was identified. Among the seven chemical methods, only the EDTA and the total soil concentration can be used to assess Cd and Pb environmental bioavailability to snails (r² adj = 0.67 and 0.77, respectively). For Zn, none of the chemical methods were suitable. Taking into account the influence of the soil characteristics (pH and CEC) allows a better prediction of Cd and Pb environmental bioavailability (r² adj = 0.82 and 0.83, respectively). Even though alone none of the chemical methods tested could assess Zn environmental bioavailability to snails, the addition of pH, iron and aluminium oxides allowed the variation of assimilation fluxes to be predicted. A conceptual and practical method to use soil characteristics for risk assessment is proposed based on these results. We conclude that as yet there is no universal chemical method to predict metal environmental bioavailability to snails, and that the soil factors having the greatest impact depend on the metal considered. - Highlights: ► New approach to identify chemical methods able to predict metal bioavailability to snails. ► Bioavailability of cadmium, lead and zinc to snails was determined by

Soil parameters are key factors to predict metal bioavailability to snails based on chemical extractant data

Energy Technology Data Exchange (ETDEWEB)

Pauget, B.; Gimbert, F., E-mail: frederic.gimbert@univ-fcomte.fr; Scheifler, R.; Coeurdassier, M.; Vaufleury, A. de

2012-08-01

Although soil characteristics modulate metal mobility and bioavailability to organisms, they are often ignored in the risk assessment of metal transfer. This paper aims to determine the ability of chemical methods to assess and predict cadmium (Cd), lead (Pb) and zinc (Zn) environmental bioavailability to the land snail Cantareus aspersus. Snails were exposed in the laboratory for 28 days to 17 soils from around a former smelter. The soils were selected for their range of pH, organic matter, clay content, and Cd, Pb and Zn concentrations. The influence of soil properties on environmental availability (estimated using HF-HClO{sub 4}, EDTA, CaCl{sub 2}, NH{sub 4}NO{sub 3}, NaNO{sub 3}, free ion activity and total dissolved metal concentration in soil solution) and on environmental bioavailability (modelled using accumulation kinetics) was identified. Among the seven chemical methods, only the EDTA and the total soil concentration can be used to assess Cd and Pb environmental bioavailability to snails (r Superscript-Two {sub adj} = 0.67 and 0.77, respectively). For Zn, none of the chemical methods were suitable. Taking into account the influence of the soil characteristics (pH and CEC) allows a better prediction of Cd and Pb environmental bioavailability (r Superscript-Two {sub adj} = 0.82 and 0.83, respectively). Even though alone none of the chemical methods tested could assess Zn environmental bioavailability to snails, the addition of pH, iron and aluminium oxides allowed the variation of assimilation fluxes to be predicted. A conceptual and practical method to use soil characteristics for risk assessment is proposed based on these results. We conclude that as yet there is no universal chemical method to predict metal environmental bioavailability to snails, and that the soil factors having the greatest impact depend on the metal considered. - Highlights: Black-Right-Pointing-Pointer New approach to identify chemical methods able to predict metal bioavailability

Removal of cadmium from aqueous solution using waste shells of golden apple snail

Science.gov (United States)

Benliang Zhao; Jia-en Zhang; Wenbin Yan; Xiaowu Kang; Chaogang Cheng; Ying Ouyang

2016-01-01

Golden apple snail (GAS) is one of the 100 worst invasive alien species. With the application of molluscicides to kill and control the spreading of these snails, a large amount of dead GAS shells are remained in many farms. This study ascertained the characteristics and removal of cadmium (Cd) by the GAS shell (GASS) powders and the associate mechanisms....

Studies on the Edible Terrestrial Snails Helix aspersa Muller Food Conversion Ratio in a Confined Microclimate System

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Adrian Toader-Williams

2010-05-01

Full Text Available Terrestrial edible snail breeding is an agricultural activity that finds itself at pioneering stage in Romania. One of the species used in snail farming is Helix aspersa Muller. In order to accelerate their growth, farmers feed the snails with pumpkins as well as concentrated forage consisting of mix of flours to which calcium carbonate is added in order to supplement snails need for shell’s development. In a controlled microclimate environment we measured the average growth of six weeks old Helix aspersa Muller snails placed in four different plastic enclosures. The consumption of different type of foods within 24 hours period was measured. The wheat (60%, corn flour (20% and calcium carbonate (20% mix had a superior food conversion ratio (FCR of 4.80, whereas the second FCR registered 6.04 in the case of 53% pumpkin and 47% flour mix served in the same time followed by the pure fresh vegetable mix accounting for a FCR of 8.00 and by 19.02 when only the pumpkin has been administrated as meal. During the experiments the snails did not have access to soil, being known that soil is an integral part of their diet.

Gut bacterial communities in the giant land snail Achatina fulica and their modification by sugarcane-based diet.

Science.gov (United States)

Cardoso, Alexander M; Cavalcante, Janaína J V; Vieira, Ricardo P; Lima, Joyce L; Grieco, Maria Angela B; Clementino, Maysa M; Vasconcelos, Ana Tereza R; Garcia, Eloi S; de Souza, Wanderley; Albano, Rodolpho M; Martins, Orlando B

2012-01-01

The invasive land snail Achatina fulica is one of the most damaging agricultural pests worldwide representing a potentially serious threat to natural ecosystems and human health. This species is known to carry parasites and harbors a dense and metabolically active microbial community; however, little is known about its diversity and composition. Here, we assessed for the first time the complexity of bacterial communities occurring in the digestive tracts of field-collected snails (FC) by using culture-independent molecular analysis. Crop and intestinal bacteria in FC were then compared to those from groups of snails that were reared in the laboratory (RL) on a sugarcane-based diet. Most of the sequences recovered were novel and related to those reported for herbivorous gut. Changes in the relative abundance of Bacteroidetes and Firmicutes were observed when the snails were fed a high-sugar diet, suggesting that the snail gut microbiota can influence the energy balance equation. Furthermore, this study represents a first step in gaining a better understanding of land snail gut microbiota and shows that this is a complex holobiont system containing diverse, abundant and active microbial communities.

Gut bacterial communities in the giant land snail Achatina fulica and their modification by sugarcane-based diet.

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Alexander M Cardoso

Full Text Available The invasive land snail Achatina fulica is one of the most damaging agricultural pests worldwide representing a potentially serious threat to natural ecosystems and human health. This species is known to carry parasites and harbors a dense and metabolically active microbial community; however, little is known about its diversity and composition. Here, we assessed for the first time the complexity of bacterial communities occurring in the digestive tracts of field-collected snails (FC by using culture-independent molecular analysis. Crop and intestinal bacteria in FC were then compared to those from groups of snails that were reared in the laboratory (RL on a sugarcane-based diet. Most of the sequences recovered were novel and related to those reported for herbivorous gut. Changes in the relative abundance of Bacteroidetes and Firmicutes were observed when the snails were fed a high-sugar diet, suggesting that the snail gut microbiota can influence the energy balance equation. Furthermore, this study represents a first step in gaining a better understanding of land snail gut microbiota and shows that this is a complex holobiont system containing diverse, abundant and active microbial communities.

Tropical Freshwater Biology

African Journals Online (AJOL)

Tropical Freshwater Biology promotes the publication of scientific contributions in the field of freshwater biology in the tropical and subtropical regions of the world. One issue is published annually but this number may be increased. Original research papers and short communications on any aspect of tropical freshwater ...

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

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Kumari Sunita

2011-01-01

Full Text Available 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.

Attraction to amino acids by Lymnaea acuminata, the snail host of Fasciola species

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Tiwari F.

2004-01-01

Full Text Available Adult Lymnaea acuminata (average length 20-22 mm were collected locally from lakes and low-lying submerged fields from Gorakhpur. The chemoattraction studies were made in round glass aquaria measuring 30 cm in diameter and filled to a depth of 10 mm with 500 ml dechlorinated tap water. Each aquarium was divided into four concentric zones. At the starting time of the assay 10 snails were placed on the circumference of outermost zone 0. Snail attractant pellets (SAP were added simultaneously in the center of central zone 3. SAP of different amino acids were prepared at concentrations of 10, 20, 50, 80 and 100 mM/2% agar solution and, subsequently, spread to a uniform thickness of 5 mm. After cooling, SAP were cut in small pieces of 5 mm in diameter. Lymnaea acuminata's attraction to amino acids was studied using different amino acid concentrations in SAP. Pellets containing amino acids with non-polar R groups (proline and tryptophan, a charged polar group (arginine and uncharged polar R groups (serine, citrulline and asparagine were tested. The snails were more attracted to the uncharged polar R group amino acid serine than to other groups of amino acids. The preferred amino acid concentration was 80 mM. The attraction of snails to different amino acids was concentration dependent. Snails could discriminate amongst the different amino acids at > or = 50 mM.

aPKC-ι/P-Sp1/Snail signaling induces epithelial-mesenchymal transition and immunosuppression in cholangiocarcinoma.

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Qian, Yawei; Yao, Wei; Yang, Tao; Yang, Yan; Liu, Yan; Shen, Qi; Zhang, Jian; Qi, Weipeng; Wang, Jianming

2017-10-01

Cholangiocarcinoma (CCA) is a highly malignant bile duct cancer that tends to invade and metastasize early. The epithelial-mesenchymal transition (EMT) has been implicated in cancer cell invasion and metastasis, as well as in cancer cell evasion of host immunity. In this study, we investigated the interaction between atypical protein kinase C-iota (aPKC-ι) and Snail in the regulation of EMT and its relationship to CCA immunosuppression. Our results demonstrated that aPKC-ι, Snail, and infiltrated immunosuppressive cells were significantly up-regulated in CCA tumor tissues and linked to poor prognosis. aPKC-ι induced EMT and immunosuppression by regulating Snail in vitro and in vivo, although aPKC-ι did not directly interact with Snail in coimmunoprecipitation experiments. To further clarify the molecular interaction between aPKC-ι and Snail in relation to EMT, quantitative iTRAQ-based phosphoproteomic analysis and liquid chromatography-tandem mass spectrometry were conducted to identify the substrates of aPKC-ι-dependent phosphorylation. Combined with coimmunoprecipitation, we showed that specificity protein 1 (Sp1) was directly phosphorylated by aPKC-ι on Ser59 (P-Sp1). Both Sp1 and P-Sp1 were up-regulated in CCA tumor tissues and associated with clinicopathological features and poor prognosis in CCA patients. Moreover, using chromatin immunoprecipitation assays, we found that P-Sp1 regulated Snail expression by increasing Sp1 binding to the Snail promoter. P-Sp1 also regulated aPKC-ι/Snail-induced EMT-like changes and immunosuppression in CCA cells. Our findings further indicated that CCA cells with EMT-like features appear to generate immunosuppressive natural T regulatory-like cluster of differentiation 4-positive (CD4 + )CD25 - cells rather than to increase CD4 + CD25 + natural T regulatory cells, in part by mediating T regulatory-inducible cytokines such as transforming growth factor β1 and interleukin 2. These results demonstrate that a

A description of the life stages of Echinoparyphium elegans ...

African Journals Online (AJOL)

The life cycle of Echinoparyphium elegans Looss 1899 is described from the Free State, South Africa.The freshwater snail Bulinus tropicus (Krauss 1848), the intermediate host of Calicophorort microbothrium (Paramphistomum microbothrium Fischoeder, 1901) in this area, serves as first intermediate host. The same snail ...

KUANTITAS ANAKAN KULTUR SEMUT RANGRANG, Oecophylla smaragdina, SECARA ARTIFISIAL DENGAN MENGGUNAKAN BEBERAPA JENIS PAKAN BERBEDA

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Lintang Dianing Ratri

2017-03-01

Full Text Available Oecophylla smaragdina or weaver ants is social insect that has an important role in the ecosystem. One of its main function is as a biological control agent in agriculture. The use of weaver ants in an effort to develop a biocontrol continues and increases, this has caused the significant decrease of the natural population of O. smaragdina. Therefore, the weaver ants rearing is needed to maintain its existence in natural habitat without excessive exploitation. The purpose of this study were to determine the effect of different types of feed i.e. snails, earthworms, and okara (tofu by-product in the production of weaver ants kroto; and to determine the different of treatments of feeds provided to the production quantity of weaver ants kroto. The experimental method used in this study with a completely randomized design. Treatment was given by different protein sources feeding i.e. snails (Pomacea canaliculata, earthworm (Lumbricus rubellus, and okara. Five replicates were appliead for each treatment. Earthworms fed ants produced highest number of kroto with total of 1,030 individuals and weight 87.4 gram in total. Snails fed ants produced 866 individuals and weight 73.1 gram. Okara fed ants produced 543 individuals and weight 45.9 gram.

[Study on the relationship between Terra-MODIS image and the snail distribution in marshland of Jiangning county, Jiangsu province].

Science.gov (United States)

Zhang, Bo; Zhang, Zhi-ying; Xu, De-zhong; Sun, Zhi-dong; Zhou, Xiao-nong; Gong, Zi-li; Liu, Shi-jun; Liu, Cheng; Xu, Bin; Zhou, Yun

2003-04-01

To analyze the relationship between the normalized difference vegetation index (NDVI) and the snail distribution in marshland of Jiangning county in Jiangsu province, and to explore the utility of Terra-MODIS image map in the small scale snail habitats surveillance. NDVI were extracted from MODIS image by vector chart of the snail distribution using ArcView 8.1 and ERDAS 8.5 software. The relationship between NDVI and the snail distribution were Investigated using Bivariate correlations and stepwise linear regression. The snail density on marshland was positively correlated with the mean NDVI in the first ten-day of May and the maximum NDVI (N(20max)) in the last ten-day of May. Incidence of pixel with the live snail on marshland was positively correlated with the mean NDVI (N(2mean)) in the first ten-day of May. An equation Y(1) = 0.009 47 x N(20max) (R(2) = 0.73), Y(2) = 0.018 6 x N(2mean) (R(2) = 0.906) was established. This study showed that the Terra-MODIS satellite images reflecting the status of the vegetation on marshland in Jiangning county could be applied to the study to supervise the snail habitat. The results suggested that MODIS images could be used to survey the small scale snail habitats on marshland.

Genetic variability and identification of the intermediate snail hosts of Schistosoma mansoni

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Teofânia HDA Vidigal

1998-01-01

Full Text Available Studies based on shell or reproductive organ morphology and genetic considerations suggest extensive intraspecific variation in Biomphalaria snails. The high variability at the morphological and genetic levels, as well as the small size of some specimens and similarities between species complicate the correct identification of these snails. Here we review our work using methods based on polymerase chain reaction (PCR amplification for analysis of genetic variation and identification of Biomphalaria snails from Brazil, Argentina, Uruguay and Paraguay. Arbitrarily primed-PCR revealed that the genome of B. glabrata exihibits a remarkable degree of intraespecific polymorphism. Low stringency-PCR using primers for 18S rRNA permited the identification of B. glabrata, B. tenagophila and B. occidentalis. The study of individuals obtained from geographically distinct populations exhibits significant intraspecific DNA polymorphism, however specimens from the same species, exhibit some species specific LSPs. We also showed that PCR-restriction fragment of length polymorphism of the internal transcribed spacer region of Biomphalaria rDNA, using DdeI permits the differentiation of the three intermediate hosts of Schistosoma mansoni. The molecular biological techniques used in our studies are very useful for the generation of new knowledge concerning the systematics and population genetics of Biomphalaria snails.

Function of insulin in snail brain in associative learning.

Science.gov (United States)

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

2015-10-01

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

Peroxisome Proliferator-Activated Receptor-γ Inhibits Transformed Growth of Non-Small Cell Lung Cancer Cells through Selective Suppression of Snail

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Rashmi Choudhary

2010-03-01

Full Text Available Work from our laboratory and others has demonstrated that activation of the nuclear receptor peroxisome proliferator-activated receptor-γ (PPARγ inhibits transformed growth of non-small cell lung cancer (NSCLC cell lines in vitro and in vivo. We have demonstrated that activation of PPARγ promotes epithelial differentiation of NSCLC by increasing expression of E-cadherin, as well as inhibiting expression of COX-2 and nuclear factor-κB. The Snail family of transcription factors, which includes Snail (Snail1, Slug (Snail2, and ZEB1, is an important regulator of epithelial-mesenchymal transition, as well as cell survival. The goal of this study was to determine whether the biological responses to rosiglitazone, a member of the thiazolidinedione family of PPARγ activators, are mediated through the regulation of Snail family members. Our results indicate that, in two independent NSCLC cell lines, rosiglitazone specifically decreased expression of Snail, with no significant effect on either Slug or ZEB1. Suppression of Snail using short hairpin RNA silencing mimicked the effects of PPARγ activation, in inhibiting anchorage-independent growth, promoting acinar formation in three-dimensional culture, and inhibiting invasiveness. This was associated with the increased expression of E-cadherin and decreased expression of COX-2 and matrix metaloproteinases. Conversely, overexpression of Snail blocked the biological responses to rosiglitazone, increasing anchorage-independent growth, invasiveness, and promoting epithelial-mesenchymal transition. The suppression of Snail expression by rosiglitazone seemed to be independent of GSK-3 signaling but was rather mediated through suppression of extracellular signal-regulated kinase activity. These findings suggest that selective regulation of Snail may be critical in mediating the antitumorigenic effects of PPARγ activators.

Radiation decontamination of Peruvian marine ''lead snail'' (Thais chocolata) inoculated with Vibrio cholerae O1 El Tor

International Nuclear Information System (INIS)

Torres, Z.; Arias, F.

2001-01-01

In vivo studies were conducted using marine snails (Thais chocolata) artificially contaminated in a tank containing sea water inoculated with a pure culture of Vibrio cholerae, such that 10 5 colony forming units per gram (CFU/g) were uptaken by the mollusks in 1.5 h. A radiation D 10 value of 0.12 kGy was determined for V. cholerae upon subsequent irradiation of the live snails at doses in the range 0.0-4.0 kGy. A second series of tests were conducted using naturally contaminated, non-inoculated snails, shelled and packaged simulating commercial procedures, irradiated at 0.0-3.0 kGy, and stored at 2-4 deg. C. These tests indicated that a dose of 2.0 kGy was optimal to extend the microbiological shelf-life of the snails to 21 days without inducing significant adverse sensory or chemical effects. Non-irradiated snails similarly treated and stored spoiled after only seven days. (author)

Dynamic of population-dynamics in a medically important snail species Lymnaea (Radix Luteola (Lamarck

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T. K. Misra

1993-09-01

Full Text Available The life-cycle parameters of the snail Lymnaea (Radix luteola and the factors influencing the same have been studied under laboratory conditions. Ins each month, from July 1990 to June 1991, a batch of 100 zero-day old individual were considered for studies. The snails of April batch survived for 19.42 days while those in December batch survived for 87.45 days. The May batch individual though survived for 65.67 days gained maximum shell size (15.84 mm in length and body weight (419.87 mg. All individuals of April batch died prior to attainment of sexual maturity. In the remaining 11 batches the snails became sexually mature between 32 and 53 days. At this stage, they were with varying shell lengths, 9.3 mm to 13,11 mm in respect to batches. The reproduction period varied from 1-67 days. An individual laid, on an average, 0,25 (March batch to 443.67 (May batch eggs in its life-span. A batch of such snails would leave 24312, 22520, 720268, 80408, 76067, 418165, 214, 9202, 0, 0, 2459386 and 127894 individuals at the end of 352nd day. Since the environmental conditions were almost similar the 'dynamic' of population dynamics seems to be involved with the 'strain' of the snail individuals of the batches concerned.

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

Science.gov (United States)

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.

[Short-term effect of black film covering on Oncomelania hupensis snail control in marshland and lake regions].

Science.gov (United States)

Zheng, Sheng-bang; Zhou, Yi-biao; Li, Lin-han; Wu, Jin-yi; Yao, Bao-dong; Zhu, Shao-ping; Wei, Cheng-jian; Li, Fu-ping; Hu, Ben-jiao; Ren, Guang-hui; Yi, Ping; Jiang, Qing-wu

2013-08-01

To evaluate the short-term effect of the black film covering combined with niclosamide on Oncomelania hupensis snail control in marshland and lake regions. A ditch with snails in Anxiang County was selected as the experimental sites. The ditch was divided into 3 groups: a film group, a niclosamide group, and a niclosamide and film group. The snails were surveyed before the test and 1, 3, 5, 7 days after the experiment. After the film covering, the highest temperature of the surface of soil was 63.7 degrees C on the first day, and the temperature higher than 40 degrees C lasted 4.34 hours. On the second day, the highest temperature was 52.3 degrees C, and the temperature higher than 40 degrees C lasted 4.96 hours. On the fourth day and fifth day, the temperature was lower than 30 degrees C, while the temperature was lower than 34 degrees C on the sixth day. On the seventh day of the experiment, the snail death rates of the film group, the niclosamide group, and the niclosamide and film group on the soil surface were 16.36%, 58.40% and 53.57%, respectively. On the seventh day, the snail death rates of the film group, and the niclosamide and film group under the soil were 20.00% and 40.00%, respectively, while no snails were found under the soil in the niclosamide group 3 days after the experiment. In mesh bags, the snail death rates of the film group, the niclosamide group, and the niclosamide and film group were 84.00%, 95.33% and 95.33%, respectively. The short-term effect of the black film covering on snail control is not obvious, and the black film covering does no promote the molluscicidal effect of niclosamide.

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

Science.gov (United States)

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

2011-01-01

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

Optimal stocking densities of snails [ Archachatina marginata ...

African Journals Online (AJOL)

Optimal stocking densities of breeding and fattening snails [Archachatina marginata Saturalis A.m.s (Swainson)] were determined through two experiments (five treatments, four replicates and randomised complete block design each) between April and December 1998.Experiment 1 had 3,6, 12, 17 and 22 A.m.s. adult ...

Forest snail diversity and its environmental predictors along a sharp climatic gradient in southern Siberia

Science.gov (United States)

Horsák, Michal; Juřičková, Lucie; Horsáková, Veronika; Pokorná, Adéla; Pokorný, Petr; Šizling, Arnošt L.; Chytrý, Milan

2018-04-01

Diversity patterns of forest snail assemblages have been studied mainly in Europe. Siberian snail faunas have different evolutionary history and colonization dynamics than European faunas, but studies of forest snail diversity are almost missing from Siberia. Therefore, we collected snails at 173 forest sites in the Russian Altai and adjacent areas, encompassing broad variation in climate and forest types. We found 51 species, with a maximum of 15 and an average of seven species per site. The main gradient in species composition was related to soil pH, a variable that also positively correlates with snail abundances. The second gradient was associated with climate characteristics of winter. We observed significant differences in both species richness and composition among six forest types defined based on vegetation classification. Hemiboreal continental forests were the poorest of these types but hosted several species characteristic of European full-glacial stages of the Late Pleistocene. A high snow cover in Temperate coniferous and mixed forests, protecting the soil from freezing, allowed the frost-sensitive large-bodied (>10 mm) species to inhabit this forest type. In contrast to most of the European snail assemblages studied so far we found that the factors responsible for the variation in species richness differed from those driving species composition. This may be attributed to the sharp climatic gradient and the presence of the cold-adapted species typical of the Pleistocene cold stages. We suggest that southern Siberian forests hosting these species can serve as modern analogues of full-glacial forests in periglacial Central and Eastern Europe.

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

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Butcher A.R.

2005-03-01

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

Scientific Opinion on the assessment of the potential establishment of the apple snail in the EU

OpenAIRE

EFSA Panel on Plant Health (PLH)

2013-01-01

EFSA requested the PLH Panel to review the current state of the art of the biology and ecology of apple snails, reported in this opinion, and to perform an environmental risk assessment for validation of the Plant Health environment guidance document, which will be provided in a second opinion. The Panel presents in this opinion the current state of the art of the biology of apple snails, and develops and uses a population dynamics model to assess the potential establishment of apple snails i...

Statement on the identity of apple snails

DEFF Research Database (Denmark)

Baker, R.; Candresse, T.; Dormannsné Simon, E.

2012-01-01

Following a request by the European Commission, EFSA’s Panel on Plant Health was asked to deliver a statement to clarify the current scientific knowledge regarding the identity of the apple snails in the context of the evaluation of the pest risk analysis prepared by the Spanish Ministry of Envir...

Growth Performance of Pekin Ducks Fed with Golden Snail and Fresh Banana Peelings

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Ulep, LJL.

1995-01-01

Full Text Available The growth performance and economics of feeding confined Pekin ducks with three different levels of golden snail fresh meat and banana peelings in equal percentage for replacing 50 %, 70 % or 90 % of the commercial feed of the diet was studied. Body weight gains and feed consumption of ducks, cost of feed and profit above feed and stock cost different significantly among treatments. Feed conversion varied during the first month of feeding but became comparable after the second month. Ducks fed the diet with 45 % banana peel and 45 % golden snail meat gave the best performance, were the most economical and yielded the highest profit. Snail meat and banana peeling utilization as replacement to commercial diet for ducks is advantageaous in terms of growth performance and cost benefit.

Large-scale determinants of intestinal schistosomiasis and intermediate host snail distribution across Africa

DEFF Research Database (Denmark)

Stensgaard, Anna-Sofie; Utzinger, Jürg; Vounatsou, Penelope

2013-01-01

The geographical ranges of most species, including many infectious disease agents and their vectors and intermediate hosts, are assumed to be constrained by climatic tolerances, mainly temperature. It has been suggested that global warming will cause an expansion of the areas potentially suitable...... impacts of climatic changes. Snail species distribution models included several combinations of climatic and habitat-related predictors; the latter divided into "natural" and "human-impacted" habitat variables to measure anthropogenic influence. The predictive performance of the combined snail...... are more likely to contract and/or move into cooler areas in the south and east. Importantly, we also note that even though climate per se matters, the impact of humans on habitat play a crucial role in determining the distribution of the intermediate host snails in Africa. Thus, a future contraction...

Effects of endocrine disruptors on prosobranch snails (Mollusca: Gastropoda) in the laboratory. Part III: Cyproterone acetate and vinclozolin as antiandrogens.

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Tillmann, M; Schulte-Oehlmann, U; Duft, M; Markert, B; Oehlmann, J

2001-12-01

The effects of suspected endocrine disrupting chemicals on freshwater and marine prosobranch species were analysed in laboratory experiments. In this last of three publications, the responses of the fresh water snail Marisa cornuarietis and of two marine prosobranchs (Nucella lapillus, Nassarius (Hinia) reticulatus) to the antiandrogenic model compounds cyproterone acetate (CPA) and vinclozolin (VZ) are presented. The snails were exposed to nominal CPA concentrations of 1.25 mg/L alone and simultaneously to a potent synthetic estrogen (ethinylestradiol), androgen (methyltestosterone) or an indirectly acting xeno-androgen (tributyltin) in experiments with adult specimens and in a life cycle test for 12 months. Marisa and Nucella were furthermore exposed to nominal concentrations of 0.03-1.0 microgram VZ/L for up to 5 months. The antiandrogens induced a number of biological responses in all three species. The length of the penis and of accessory male sex organs (e.g., penis sheath, prostate) were significantly reduced. For Marisa, this effect occurred only in sexually immature specimens and was reversible as the males attained puberty. Typical androgen-mediated responses (imposex development, delayed spermatogenesis, tubulus necrosis of the testis with orchitis and Leydig cell hyperplasia) were partially or totally suppressed by a simultaneous administration of CPA. In the two marine species even adult, sexually mature males responded to antiandrogens with a reduction of the male sex organs and an advancement of the sexual repose phase. The results for CPA and VZ are compared with the effects of an exposure to xeno-estrogens (bisphenol A, octylphenol) and xeno-androgens (triphenyltin, tributyltin) in the same species. Each group of endocrine disruptors induces a characteristic set of toxicological effects in prosobranch snails which can be used as endpoints in an organismic invertebrate test for the identification of endocrine mimetic test compounds. Estrogens cause

Responses of Withdrawal Interneurons to Serotonin Applications in Naïve and Learned Snails Are Different

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Tatiana K. Bogodvid

2017-12-01

Full Text Available Long-term changes in membrane potential after associative training were described previously in identified premotor interneurons for withdrawal of the terrestrial snail Helix. Serotonin was shown to be a major transmitter involved in triggering the long-term changes in mollusks. In the present study we compared the changes in electrophysiological characteristics of identifiable premotor interneurons for withdrawal in response to bath applications of serotonin (5-HT or serotonin precursor 5-hydroxytryptophan (5-HTP in preparations from naïve, neurotoxin-injected or associatively trained snails. It was found that 5-HT or 5-HTP applications caused a significant decrease of membrane potential in premotor interneurons of naïve snails, associatively trained snails and snails with impaired serotonergic system by injection of a selective neurotoxin 5,7-dihydroxytryptamine (5,7-DHT 1 week before the experiments. Applications of 5-HT or 5-HTP did not cause significant changes in the action potential (AP threshold potential of these neurons in naïve snails. Conversely, applications of 5-HT or 5-HTP to the premotor interneurons of previously trained or 5,7-DHT-injected snails caused a significant increase in the firing threshold potential in spite of a depolarizing shift of the resting membrane potential. Results demonstrate that responsiveness of premotor interneurons to extracellularly applied 5-HT or 5-HTP changes for days after the associative training or serotonin depletion. Similarity of the effects in trained and 5,7-DHT-injected animals may be due to massive release of serotonin elicited by 5,7-DHT injection. Our results suggest that serotonin release due to aversive conditionining or elicited by the neurotoxin administration triggers similar changes in resting membrane potential and AP threshold in response to bath applications of 5-HT or its precursor 5-HTP.

Hsp70 in the atrial neuroendocrine units of the snail, Achatina fulica.

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Martynova, M G; Bystrova, O A; Shabelnikov, S V; Margulis, B A; Prokofjeva, D S

2007-04-01

Heat shock proteins (Hsps) are evolutionary conserved peptides well known as molecular chaperones and stress proteins. Elevated levels of extracellular Hsps in blood plasma have been observed during the stress responses and some diseases. Information on the cellular sources of extracellular Hsps and mechanisms regulating their release is still scanty. Here we showed the presence and localization of Hsp70 in the neuroendocrine system in the atrium of the snail, Achatina fulica. The occurrence of the peptide in snail atrium lysate was detected by Western blot analysis. Immunoperoxidase and immunogold staining demonstrated that Hsp70-immunoreactivity is mainly confined to the peculiar atrial neuroendocrine units which are formed by nerve fibers tightly contacted with large granular cells. Immunolabelling intensity differed in morphologically distinct types of secretory granules in the granular cells. The pictures of exocytosis of Hsp70-immunolabeled granules from the granular cells were observed. In nerve bundles, axon profiles with Hsp70-immunoreactive and those with non-immunoreactive neurosecretory granules were found. In addition, Hsp70-like material was also revealed in the granules of glia-interstitial cells that accompanied nerve fibers. Our findings provide an immuno-morphological basis for a role of Hsp70 in the functioning of the neuroendocrine system in the snail heart, and show that the atrial granular cells are a probable source of extracellular Hsp70 in the snail hemolymph.

NUTRITIONAL VALUE OF CHICKEN OFFAL AS REPLACEMENT FOR LOCAL FISH MEAL IN GROWING SNAILS

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A OMOLE

2009-03-01

Full Text Available A total of ninety six growing snails of mean weight 91.23±2.4g were used to determine the effects of partial or total replacement of local fish meal, a source of protein but expensive to a less expensive, alternative source, chicken offal in the diet of growing snails. Completely randomized design was used for the study. The feeding trial had four treatments, C1, C2, C3 and C4 in which fish meal fraction of the diets was replaced at 0, 50, 75 and 100% with chicken offal respectively. The parameters taken were weight gain, feed intake. Feed conversion ratio, total feed cost, and cost per weight gain were calculated. The trial lasted for twelve weeks. Significant differences were not observed in the mean weekly feed intake of the snails in all the treatments. The mean weight gain in all the treatments were not significantly influenced by the inclusion of chicken offal in the diet (P>0.005. Total feed cost and cost/weight gain reduced as the level of the chicken offal increased while the lowest cost/weight gain was observed in C4. The inclusion of Chicken offal in all the diets had no detrimental effect on the snails in all the treatments. Based on the present results chicken offal could replace local fish meal in the diet of growing snail up to 100% and hereby reduce feed cost

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

Science.gov (United States)

2010-06-22

... means that the snail has a rounded plate that seals the mouth of the shell while the snail is inside... Conservation measures provided to species listed as endangered or threatened under the Act include recognition.... Recognition through listing increases public awareness of threats to the tulotoma, and promotes conservation...

[Species composition and distribution of medical mollusca in Shanghai City].

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Guo, Yun-hai; Lv, Shan; Gu, Wen-biao; Liu, He-xiang; Wu, Ying; Zhang, Yi

2015-02-01

To investigate the species diversity and distribution of medical mollusca in Shanghai City. From August 2012 to October 2013, all kinds of habitats in 8 districts and counties in Shanghai City, namely Jiading, Qingpu, Baoshan, Minhang, Songjiang, Jinshan, Chongming, Pudong, were selected for the field survey according to the distribution characteristics of the river system, and all the specimens of medical mollusca in the investigation sites were collected and classified by morphological identification. Meanwhile, the species composition, habitats as well as the fauna of the medical mollusca collected were analyzed. A total of 5,211 specimens were collected, which belonged to 2 classes, 14 families, 18 genera and 25 species, including Oncomelania hupensis hupensis, Pomacea canaliculata, Parafossarulus striatulus, Alocinma longicornis, Physa acuta, Galba pervia, Hippeutis cantori, etc. The species numbers of medical mollusca in Chongming, Jinshan, Pudong new area and Qingpu districts (counties) were 22, 22, 21 and 20, respectively, which were more than those of other areas. The habitat analysis suggested that the species numbers in the river and wetland were the most, both of which were 14 species. The main faunas of the medical mollusca in Shanghai were the cosmopolitan and oriental species. The freshwater gastropod species are paucity in Shanghai City, but almost of them can be served as the intermediate hosts of certain parasites to transmit snail-related parasitic diseases, so the surveillance of medical mollusca should be strengthened.

[Neuroeffector connections of multimodal neurons in the African snail (Achatina fulica)].

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Bugaĭ, V V; Zhuravlev, V L; Safonova, T A

2004-02-01

Using a new method of animal preparation, the efferent connections of giant paired neurons on the dorsal surface of visceral and right parietal ganglia of snail, Achatina fulica, were examined. It was found that spikes in giant neurons d-VLN and d-RPLN evoke postjunctional potentials in different points of the snail body and viscerae (in the heart, in pericardium, in lung cavity and kidney walls, in mantle and body wall muscles, in tentacle retractors and in cephalic artery). The preliminary analysis of synaptic latency and facilitation suggests a direct connections between giant neurons and investigated efferents.

Fulicin regulates the female reproductive organs of the snail, Achatina fulica.

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Fujisawa, Y; Masuda, K; Minakata, H

2000-08-01

Fulicin is a D-amino acid-containing neuropeptide that has been thought to control male copulatory behavior in the land snail, Achatina fulica. In the present study, we demonstrated that the vagina and the oviduct of Achatina were densely innervated by fulicin-like immunoreactive neuronal fibers. We confirmed that fulicin was actually present in the vagina by mass spectrometry. Furthermore, fulicin showed a profound excitatory effect on contractions of the vagina and the oviduct. These results suggest that fulicin controls female egg-laying behavior as an excitatory neuropeptide regulating the female reproductive organs of the snail.

Distribution of transuranic elements in a freshwater pond ecosystem

International Nuclear Information System (INIS)

Emery, R.M.; Klopfer, D.C.

1975-05-01

Preliminary results are reported from a study initiated on the Hanford Reservation concerning the ecological behavior of 238 Pu, 239 Pu, 240 Pu, and 241 Am in a freshwater environment. This study involves a waste pond which has been receiving Pu processing wastes for about 30 years. The pond has a sufficiently established ecosystem to provide an excellent location for limnological characterization. In addition, the ecological distribution of Pu and Am was investigated. The pond is also highly enriched with nutrients, thus supporting a high level of algal and macrophyte production. Seston (30 percent diatoms) appears to be the principal concentrators of Pu transuranics in the pond system. The major sink for Pu and Am in this system is the sediments. Organic floc, overlaying the pond sediments, is also a major concentrator of transuranics in this system []Aside from the seston and floc, no other ecological components of the pond appear to have concentrations significantly greater than those of the sediment. Dragonfly, larvae, watercress, and snails show concentrations which approximate those of the sediments but nearly all other food web components have levels of Pu and Am which are lower than those of the sediments, thus, Pu and Am seem to be relatively immobile in the aquatic ecosystem. (CH)

Adaptation of Lymnaea fuscus and Radix balthica to Fasciola hepatica through the experimental infection of several successive snail generations

Science.gov (United States)

2014-01-01

Background High prevalence of Fasciola hepatica infection (>70%) was noted during several outbreaks before the 2000s in several French farms where Galba truncatula is lacking. Other lymnaeids such as Lymnaea fuscus, L. glabra and/or Radix balthica are living in meadows around these farms but only juvenile snails can sustain complete larval development of F. hepatica while older snails were resistant. The low prevalence of infection (<20%) and limited cercarial production (<50 cercariae per infected snail) noted with these juveniles could not explain the high values noted in these cattle herds. As paramphistomosis due to Calicophoron daubneyi was not still noted in these farms, the existence of another mode of infection was hypothesized. Experimental infection of several successive generations of L. glabra, originating from eggs laid by their parents already infected with this parasite resulted in a progressive increase in prevalence of snail infection and the number of shed cercariae. The aim of this paper was to determine if this mode of snail infection was specific to L. glabra, or it might occur in other lymnaeid species such as L. fuscus and R. balthica. Methods Five successive generations of L. fuscus and R. balthica were subjected to individual bimiracidial infections in the laboratory. Resulting rediae and cercariae in the first four generations were counted after snail dissection at day 50 p.e. (20°C), while the dynamics of cercarial shedding was followed in the F5 generation. Results In the first experiment, prevalence and intensity of F. hepatica infection in snails progressively increased from the F1 (R. balthica) or F2 (L. fuscus) generation. In the second experiment, the prevalence of F. hepatica infection and the number of shed cercariae were significantly lower in L. fuscus and R. balthica (without significant differences between both lymnaeids) than in G. truncatula. Conclusion The F. hepatica infection of several successive snail generations

Biosorption of radionuclides by snail shell biomass

International Nuclear Information System (INIS)

Dhami, P.S.; Chaudhari, S.D.; Rathinam, M.; Gopalakrishnan, V.; Ramanujam, A.

2001-01-01

The sorption of various radionuclides from low acidic and alkaline medium was studied using biomass of snail shell origin. Quantitative removal of plutonium was achieved when an alkaline waste effluents of PUREX origin at pH 9.4 was treated using this biomass. The sorbed activity was recovered by dissolving it in 1.0 M nitric acid. (author)

Impact of the Three Gorges project on ecological environment changes and snail distribution in Dongting Lake area.

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Feiyue Li

2017-07-01

Full Text Available The Three Gorges Dam (TGD is a remarkable, far-reaching project in China. This study was conducted to assess the impact of TGD on changes in the ecological environment, snail distribution and schistosomiasis transmission in Dongting Lake area.Hydrological data were collected from 12 monitoring sites in Hunan section of Yangtze River before and after TGD was established. Data on snail distribution and human schistosomiasis infection were also collected. Correlation analyses were performed to detect the significance of snail distribution to changes in ecological environmental factors and human schistosomiasis infection.A series of ecological environmental factors have changed in Dongting Lake area following the operation of TGD. Volume of annual runoff discharged into Dongting Lake declined by 20.85%. Annual sediment volume discharged into the lake and the mean lake sedimentation rate decreased by 73.9% and 32.2%, respectively. From 2003 to 2015, occurrence rate of frames with living snails and mean density of living snails decreased overall by 82.43% and 94.35%, respectively, with annual decrements being 13.49% and 21.29%. Moreover, human infection rate of schistosomiasis had decreased from 3.38% in 2003 to 0.44% in 2015, with a reduction of 86.98%. Correlation analyses showed that mean density of living snails was significantly associated with water level (r = 0.588, p<0.001, as well as the mean elevation range of the bottomland (r = 0.374, p = 0.025 and infection rate of schistosomiasis (r = 0.865, p<0.001.Ecological environmental changes caused by the TGD were associated with distribution of snails, and might further affect the transmission and prevalence of schistosomiasis. Risk of schistosomiasis transmission still exists in Dongting Lake area and long-term monitoring is required.

Conservation status of freshwater gastropods of Canada and the United States

Science.gov (United States)

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

2013-01-01

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

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

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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.

Study on the relationship of abnormal transcription factors OCT4, HBP1 and Snail expression with progression of osteosarcoma

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Li Li

2016-09-01

Full Text Available Objective: To study the relationship of abnormal transcription factors OCT4, HBP1 and Snail expression with progression of osteosarcoma. Methods: Surgical removed osteosarcoma tissue specimens were selected as pathology group, surgically removed osteoid osteoma specimens were selected as control group, and the expression levels of gene transcription factors OCT4, HBP1 and Snail, proliferation genes, epithelial-mesenchymal transition marker molecules in tissue specimens were determined. Results: Oct4 and Snail protein levels of pathology group were significantly higher than those of control group and HBP1 protein level was significantly lower than that of control group; C-myc and cyclinD1 protein levels of pathology group were significantly higher than those of control group, positively correlated with OCT4 and negatively correlated with HBP1; p16 and p53 protein levels were significantly lower than those of control group, negatively correlated with OCT4 and positively correlated with HBP1; N-cadherin and Vimentin protein levels of pathology group were significantly higher than those of control group and positively correlated with Snail while E-cadherin and Occludin protein levels were significantly lower than those of control group and negatively correlated with Snail. Conclusion: Oct4 and Snail are highly expressed and HBP1 is lowly expressed in osteosarcoma tissue, Oct4 and Snail can participate in the regulation of cell proliferation, and HBP1 can participate in the regulation of epithelial-mesenchymal transition of cells.

Observations on the morphology of Pomacea lineata (Spix, 1827 (Mollusca, Ampullariidae Observações sobre a morfologia de Pomacea lineata (Spix, 1827 (Mollusca, Ampullaridae

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Silvana Carvalho Thiengo

1987-12-01

Full Text Available This paper deals with the morpholgy of Pomacea lineata (Spix, 1827 collected at its type locality. The shell is globose, moderately heavy, horn-colored with brown spiral bands; apex subelevated; 4 - 5 rounded whorls increasing in diameter rather rapidly, separated by deep suture. Aperture large and ovoid; outer lip sharp; umbilicus narrow and deep; operculum concentric, corneous. Ratios: shell width/shell length = 0.74 - 0.83 (mean 0.78; spire length/shell length = 0.10 - 0.18 (mean 0.13; aperture length/shell length = 0.70 - 0.77 (mean 0.73. The animal is longisiphonate. Renal organ brownish with marked invagination at its right edge. Ureter elongated with its long axis transverse to the main axis of the kidney. The radula is taenioglossate (2.1.1.1.2 and has on average 35 transverse rows of teeth. The form and arrangement of the radula teeth are nearly the same as in other Ampullariidae. The testis is cream-colored and lies in the first three whorls of the spire. Spermiduct uniformly narrow, running to the base of the spire. Seminal vesicle whitish, slightly pressed dorsoventrally. Prostate cylindric and thick, similar in color to the testis. Penis whiplike, with a closed circular spermiduct. Penis pouch ovoid completely envelping the penis. Penis sheath elongated, broad prosimally, tapering distally. Its inner surface shows a longitudinal channel along its proximal half and two glands, one on the middle and the other apical. Ovary composed of branched whitish tubules situated on the surface of the digestive gland. Oviduct slender running along the columellar axis toward the base of the spire. Seminal receptalble tubiform, thick-walled and rounded proximally. Albumen gland large, pink, enclosing the receptacle and the spiral capsule gland. Vestigial male copulatory apparatus (penis and its sheath present in all females examined.Neste trabalho e estudada a morfologia de Pomacea lineata (Spix, 1827 baseada em material coletado na localidade

Concentration and retention of Toxoplasma gondii oocysts by marine snails demonstrate a novel mechanism for transmission of terrestrial zoonotic pathogens in coastal ecosystems

Science.gov (United States)

Krusor, Colin; Smith, Woutrina A.; Tinker, M. Tim; Silver, Mary; Conrad, Patricia A.; Shapiro, Karen

2015-01-01

The parasite Toxoplasma gondii is an environmentally persistent pathogen that can cause fatal disease in humans, terrestrial warm-blooded animals and aquatic mammals. Although an association between T. gondii exposure and prey specialization on marine snails was identified in threatened California sea otters, the ability of kelp-dwelling snails to transmit terrestrially derived pathogens has not been previously investigated. The objective of this study was to measure concentration and retention of T. gondii by marine snails in laboratory aquaria, and to test for natural T. gondii contamination in field-collected snails. Following exposure to T. gondii-containing seawater, oocysts were detected by microscopy in snail faeces and tissues for 10 and 3 days respectively. Nested polymerase chain reaction was also applied as a method for confirming putative T. gondii oocysts detected in snail faeces and tissues by microscopy. Toxoplasma gondiiwas not detected in field-collected snails. Results suggest that turban snails are competent transport hosts for T. gondii. By concentrating oocysts in faecal pellets, snails may facilitate entry of T. gondii into the nearshore marine food web. This novel mechanism also represents a general pathway by which marine transmission of terrestrially derived microorganisms can be mediated via pathogen concentration and retention by benthic invertebrates.

Three Gorges Dam: Impact of Water Level Changes on the Density of Schistosome-Transmitting Snail Oncomelania hupensis in Dongting Lake Area, China.

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Jin-Yi Wu

Full Text Available Schistosomiasis remains an important public health issue in China and worldwide. Oncomelania hupensis is the unique intermediate host of schistosoma japonicum, and its change influences the distribution of S. japonica. The Three Gorges Dam (TGD has substantially changed the ecology and environment in the Dongting Lake region. This study investigated the impact of water level and elevation on the survival and habitat of the snails.Data were collected for 16 bottomlands around 4 hydrological stations, which included water, density of living snails (form the Anxiang Station for Schistosomiasis Control and elevation (from Google Earth. Based on the elevation, sixteen bottomlands were divided into 3 groups. ARIMA models were built to predict the density of living snails in different elevation areas.Before closure of TGD, 7 out of 9 years had a water level beyond the warning level at least once at Anxiang hydrological station, compared with only 3 out of 10 years after closure of TGD. There were two severe droughts that happened in 2006 and 2011, with much fewer number of flooding per year compared with other study years. Overall, there was a correlation between water level changing and density of living snails variation in all the elevations areas. The density of living snails in all elevations areas was decreasing after the TGD was built. The relationship between number of flooding per year and the density of living snails was more pronounced in the medium and high elevation areas; the density of living snails kept decreasing from 2003 to 2014. In low elevation area however, the density of living snails decreased after 2003 first and turned to increase after 2011. Our ARIMA prediction models indicated that the snails would not disappear in the Dongting Lake region in the next 7 years. In the low elevation area, the density of living snails would increase slightly, and then stabilize after the year 2017. In the medium elevation region, the change of

Diversity and biogeography of land snails (Mollusca, Gastropoda) in the limestone hills of Perak, Peninsular Malaysia

Science.gov (United States)

Foon, Junn Kitt; Clements, Gopalasamy Reuben; Liew, Thor-Seng

2017-01-01

Abstract Limestone hills are now gaining global conservation attention as hotspots for short-range endemic species. Levels of land snail endemism can be high at limestone hills, especially at hill clusters that are geographically isolated. In the State of Perak, Peninsular Malaysia, limestone hills have been opportunistically surveyed for land snails in the past, but the majority have yet to be surveyed. To address this knowledge gap, we systematically surveyed the terrestrial malacofauna of 12 limestone hills that, based on our opinion, are a representation of the limestone land snail assemblages within the State. Our inventory yielded high sampling completeness (>85%). We found 122 species of land snails, of which 34 species were unique to one of the surveyed hills. We identified 30 species that are potentially new to science. The number of land snail species recorded at each hill ranged between 39 and 63 species. Four of the sampled limestone hills namely, Prk 01 G. Tempurung, Prk 55 G. Pondok, Prk 47 Kanthan, and Prk 64 Bt Kepala Gajah, have high levels of species richness and unique species, representing 91% of the total species recorded in this study. We identified two clusters of limestone hills in central Perak with distinct differences in land snail species composition – a northern hill cluster on elevated granite bedrock and southern hill cluster in a low-lying valley surrounded by alluvial soils. As limestone hills continue to be quarried to meet the cement demand, the four identified limestone hills, along with other hills from the two clusters, warrant urgent conservation attention in order to maintain high species diversity within Perak’s terrestrial malacofauna. PMID:28769723

Susceptibility of Biomphalaria spp. to infection with Schistosoma mansoni in sympatric and allopatric combinations with observations on the genetic variability between snails.

Science.gov (United States)

Mostafa, Osama M S; El-Dafrawy, Shadia M

2011-08-25

This investigation was carried out to study the susceptibility of Saudi Biomphalaria arabica to Egyptian Schistosoma mansoni in comparison with the susceptibility of Egyptian Biomphalaria alexandrina to the same parasite. This was in order to know the possibility that the parasite might be able to spread into Saudi Arabia and to determine the genetic variability between Egyptian B. alexandrina and Saudi Biomphalaria arabica snails. Lab bred Egyptian B. alexandrina and Saudi B. arabica snails were exposed individually to 10 freshly hatched Egyptian S. mansoni miracidia/snail. The mortality rate, infection rate, prepatent period, duration of cercarial shedding and cercariae production per snail were recorded in both the sympatric couple (Egyptian B. alexandrina and Egyptian S. mansoni) and in the allopatric combination (Saudi B. arabica and Egyptian S. mansoni). The results revealed that, the survival rate of snails exposed to Egyptian S. mansoni miracidia at 34th day post-exposure (at first cercarial shedding) was higher in B. arabica than in B. alexandrina. After shedding, the mortality rate was higher in the B. arabica, compared to B. alexandrina. The infection rate was higher in B. arabica than B. alexandrina; the mean of prepatent period was shorter in the B. arabica than in the B. alexandrina. However, the duration of cercarial shedding was longer in the Egyptian snails and the cercarial production per snail was higher in B. alexandrina snails than in B. arabica. To study the genetic variability between B. alexandrina and B. arabica, RAPD-PCR on the genomic DNA of snails was done. RAPD-PCR revealed significant variation between the two snail species. In conclusion, the results suggest that B. arabica can play a role in the transmission of Egyptian S. mansoni in Saudi Arabia and therefore this parasite might be able to spread into the Kingdom. In addition, the RAPD-PCR results demonstrated genetic variability between the two species which may be related to the

Oxidation of glucose-U-/sup 14/C and synthesis of glycogen in different tissues of the garden snail, Cryptozona ligulata with reference to aestivation and starvation

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Krupanidhi, S; Raghavaiah, K; Padmanabha Naidu, B; Ramamurthi, R [Sri Venkateswara Univ., Tirupati (India). Dept. of Zoology

1978-03-01

The percent decrease of glycogen content in all the tissues investigated is more in 20-days starved snails than the 4-months aestivated snails when compared to active snails. Recovery of administered glucose-U/sup 14/C in the respiratory CO/sub 2/ is 42.27 % in active snails, whereas it is 8.81 % and 26.09 % in aestivated and starved snails respectively. Maximum levels of incorporation labelled glucose were found at 18 hr in all the tissues and the rate of incorporation was greatly elevated in the tissues of aestivated and starved snails. The causes for the difference in the rates of incorporation and the utilization of glycogen in active, aestivated and starved snails are discussed.

Toxicidade aguda do sulfato de cobre e do extrato aquoso de folhas secas de nim para o caramujo (Pomacea canaliculata - DOI: 10.4025/actascibiolsci.v30i2.3615 Acute toxicity of copper sulfate and aqueous extract of dried neem leaves on snails (Pomacea canaliculata - DOI: 10.4025/actascibiolsci.v30i3.3615

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Robinson Antonio Pitelli

2008-05-01

Full Text Available Os caramujos podem se tornar um problema ambiental e econômico, podendo causar muitos prejuízos. O trabalho teve como objetivo estimar a toxicidade aguda do sulfato de cobre pentaidratado (CuSO4.5H2O e do extrato aquoso de folhas secas de nim para o P. canaliculata, em condição de laboratório. Para determinação da CL (I(50;96h, o caramujo foi exposto a seis concentrações crescentes de sulfato de cobre (0,0; 0,01; 0,03; 0,05; 0,07 e 0,1 mg L-1 e a seis concentrações crescentes de extrato aquoso de folhas secas de nim (0,0; 100; 125; 150; 175 e 200 mL de extrato aquoso de folhas secas de nim L-1 de água, equivalente a 0,0; 1,18; 1,47; 1,77; 2,06; e 2,36 mg de azadiractina L-1, com três repetições e um tratamento-controle em um experimento no delineamento inteiramente casualizado (DIC. A CL (I(50;96h estimada para o caramujo foi de 0,07 mg de sulfato de cobre L-1, com limite inferior de 0,05 mg L-1 e limite superior de 0,1 mg L-1. A concentração letal 50% (CL (I50;96h estimada do extrato aquoso de folhas secas de nim (EAFSN para o caramujo foi de 142,75 mL L-1, equivalente a 1,68 mg L-1 de azadiractina, com limite inferior de 130,89 mL L-1 (1,54, mg L-1 e limite superior de 155,69 mL L-1 (1,83 mg L-1.Snails can become an environmental and economic problem, causing substantial losses. The objective of this work was to estimate the acute toxicity of copper sulfate pentahydrate (CuSO4.5H2O and the aqueous extract of dried neem leaves on snails (P. canaliculata under laboratory conditions. In order to estimate the lethal concentration 50% (LC (I50;96h, snails were exposed to six increasing copper sulfate concentrations (0.0; 0.01; 0.03; 0.05; 0.07 and 0.1 mg L-1 and six increasing concentrations of aqueous extract of dried neem leaves 0.0; 100; 125; 150; 175 and 200 mL aqueous extract of dried neem leaves L-1 water, equivalent to (0.0; 1.18; 1.47; 1.77; 2.06; and 2.36 mg azadirachtin L-1, in triplicate and one control treatment in an

Thevetia peruviana (Family: Apocynaceae in the control of slug and snail pests

Directory of Open Access Journals (Sweden)

A. Panigrahi

1994-06-01

Full Text Available An aqueous extract prepared from Kernels of the fruit of Thevetia peruviana (Pers. Schumann (Family : Apocynaceae was found under experimental conditions, to be toxic ti the slug Laevicaulis alte (Férussac and the snail Achatina fulica Bowdich, the important agrihorticultural pests of Indo-Pacific countries. Concentrations as low as 1% (w/v killed all the slugs exposed in less than 981.00 (± SD 22.76 min, and 2% of the extract killed 100% of the slugs L. alte and 50%, 50% and 30% of the snail A. fulica in between 92.34 (± SD 6.63 - 321.33 (± SD 4.14 and 271.20 (± SD 17.54 - 298.26 (± SD 16.69 min respectively. The most effective concentration of the extract was 20%; it killed 100% of exposed slugs and snails within a short time (40-50 and 90-1440 min respectively when the extract was exposed on the soil in experimental trays or when it was applied to potato slices offered as food to the gastropods.

Freshwater Fish Communities

Science.gov (United States)

Freshwater fish are ecologically important in stream ecosystems, and they provide people with significant food, recreation, and conservation value as biological indicator of freshwater streams. Historically, the streams and rivers of southern New England supported moderately dive...

Exploring Freshwater Science

Indian Academy of Sciences (India)

and long term studies on mapping freshwater biodiversity1. 1. R J Ranjit Daniels ... The hierarchical nature of stream organization offers opportunity to ecologists to ask .... threats, freshwater systems are losing their aesthetic value (Fig- ure 4).

Prevalence and Intensity of Urinary Schistosomiasis in Abarma

African Journals Online (AJOL)

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eggs/10ml of urine while the least infection rate occurred within the 30-. 39 years and 50-59 ... had the highest infection rate of 100.0% while those that went to the ... They hatch in freshwater and infect the appropriate aquatic snail intermediate hosts. Bulinus snails are intermediate host for S. haematobium. (Ukoli, 1984).

Elevated native terrestrial snail abundance and diversity in association with an invasive understory shrub, Berberis thunbergii, in a North American deciduous forest

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Utz, Ryan M.; Pearce, Timothy A.; Lewis, Danielle L.; Mannino, Joseph C.

2018-01-01

Invasive terrestrial plants often substantially reshape environments, yet how such invasions affect terrestrial snail assemblages remains understudied. We investigated how snail assemblages in deciduous forest soils with dense Berberis thunbergii (Japanese barberry), an invasive shrub in eastern North America, differ from forest areas lacking the shrub. Leaf litter and soil samples were collected from forest patches with dense B. thunbergii understories and adjacent control areas within two exurban forest tracts in western Pennsylvania, U.S.A. Snails were identified to species and quantified by standard diversity metrics. Contrary to our expectations, snails were significantly more abundant and diverse in B. thunbergii-invaded areas. Despite differences in abundance, the snail community composition did not differ between invaded and control habitats. The terrestrial snail assemblage we observed, which was composed entirely of native species, appears to respond favorably to B. thunbergii invasion and therefore may not be negatively impacted by physicochemical changes to soils typically observed in association with the plant. Such findings could reflect the fact that B. thunbergii likely creates more favorable habitat for snails by creating cooler, more humid, and more alkaline soil environments. However, the snail assemblages we retrieved may consist mostly of species with high tolerance to environmental degradation due to a legacy of land use change and acid deposition in the region.

Polyethylene Glycol Mediated Colorectal Cancer Chemoprevention: Roles of Epidermal Growth Factor Receptor and Snail

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Wali, Ramesh K.; Kunte, Dhananjay P.; Koetsier, Jennifer L.; Bissonnette, Marc; Roy, Hemant K.

2008-01-01

Polyethylene glycol (PEG) is a clinically widely used agent with profound chemopreventive properties in experimental colon carcinogenesis. We previously reported that Snail/β-catenin signaling may mediate the suppression of epithelial proliferation by PEG, although the upstream events remain unclear. We report herein the role of epidermal growth factor receptor (EGFR), a known mediator of Snail and overepressed in ~80% of human colorectal cancers (CRC), on PEG-mediated anti-proliferative and hence anti-neoplastic effects in azoxymethane (AOM)-rats and HT-29 colon cancer cells. AOM-rats were randomized to either standard diet or one with 10% PEG 3350 and euthanized 8 weeks later. The colonic samples were subjected to immunohistochemical or Western blot analyses. PEG decreased mucosal EGFR by 60% (pPEG effects were obtained in HT-29 cells. PEG suppressed EGFR protein via lysosmal degradation with no change in mRNA levels. To show that EGFR antagonism per se was responsible for the antiproliferative effect, we inhibited EGFR by either pre-treating cells with gefitinib or stably transfecting with EGFR-shRNA and measured the effect of PEG on proliferation. In either case PEG effect was blunted suggesting a vital role of EGFR. Flow cytometric analysis revealed that EGFR-shRNA cells, besides having reduced membrane EGFR also expressed low Snail levels (40%), corroborating a strong association. Furthermore, in EGFR silenced cells PEG effect on EGFR or Snail was muted, similar to that on proliferation. In conclusion, we show that EGFR is the proximate membrane signaling molecule through which PEG initiates antiproliferative activity with Snail/β-catenin pathway playing the central intermediary function. PMID:18790788

Polyethylene glycol-mediated colorectal cancer chemoprevention: roles of epidermal growth factor receptor and Snail.

Science.gov (United States)

Wali, Ramesh K; Kunte, Dhananjay P; Koetsier, Jennifer L; Bissonnette, Marc; Roy, Hemant K

2008-09-01

Polyethylene glycol (PEG) is a clinically widely used agent with profound chemopreventive properties in experimental colon carcinogenesis. We reported previously that Snail/beta-catenin signaling may mediate the suppression of epithelial proliferation by PEG, although the upstream events remain unclear. We report herein the role of epidermal growth factor receptor (EGFR), a known mediator of Snail and overexpressed in approximately 80% of human colorectal cancers, on PEG-mediated antiproliferative and hence antineoplastic effects in azoxymethane (AOM) rats and HT-29 colon cancer cells. AOM rats were randomized to either standard diet or one with 10% PEG-3350 and euthanized 8 weeks later. The colonic samples were subjected to immunohistochemical or Western blot analyses. PEG decreased mucosal EGFR by 60% (P PEG effects were obtained in HT-29 cells. PEG suppressed EGFR protein via lysosmal degradation with no change in mRNA levels. To show that EGFR antagonism per se was responsible for the antiproliferative effect, we inhibited EGFR by either pretreating cells with gefitinib or stably transfecting with EGFR-short hairpin RNA and measured the effect of PEG on proliferation. In either case, PEG effect was blunted, suggesting a vital role of EGFR. Flow cytometric analysis revealed that EGFR-short hairpin RNA cells, besides having reduced membrane EGFR, also expressed low Snail levels (40%), corroborating a strong association. Furthermore, in EGFR silenced cells, PEG effect on EGFR or Snail was muted, similar to that on proliferation. In conclusion, we show that EGFR is the proximate membrane signaling molecule through which PEG initiates antiproliferative activity with Snail/beta-catenin pathway playing the central intermediary function.

Freshwater and fish

International Nuclear Information System (INIS)

Saxen, R.

1997-01-01

Severe radioactive contamination of the freshwater environment could have serious consequences for both drinking water and fish. Most of the Nordic countries have an abundance of freshwater lakes and rivers. Finland alone has about 56,000 lakes, each with a surface area of 1 hectare or more. Nearly 10% of Finland's surface is covered with lakes and rivers. In Sweden, about 9% of the surface area is freshwater, in Norway about 5%, and in Denmark only about 2%. Freshwater plays a minor role in Iceland, but even there numerous rivers discharge from the volcanic soils to the Ocean. Cs-137 and 90 Sr are likely to be the most important radionuclides with respect to long term radioactive contamination of freshwater. If radioactive deposition occurs in the absence of snow and ice radionuclides will contaminate the surface water directly and may rapidly enter the aquatic food chain. Fish which eat contaminated plankton become contaminated almost immediately. Deposition during summer increases the transfer for radionuclides to fish since fish metabolism is faster during the warm season. During the cold period, fish metabolism is slow and thus uptake and excretion of radiocaesium are also slow. (EG)

The susceptibility of Marisa cornuarietis, a predator of schistosome bearing snails, to N-tritylmorpholine.

Science.gov (United States)

Meier-Brook, C; Tjhen, K Y

1977-03-01

Introduction of the ampullariid snail, Marisa cornuarietis (L.), into water treated with molluscicides, in order to secure the success of chemical control of schistosome host snails, is promising. Adult Marisa can be introduced only two days after treating water of pH less than or equal to 7-9 with N-tritylmorpholine (= FresconR Shell) at a concentration of 0-03 ppm. There is considerable variation in the susceptibility of different strains: the LT50 in a concentration of 0-03 ppm Frescon at 25 degrees C was about 27-3 hours for a Puerto Rican and 44-6 hours for a Floridan strain, both 52 weeks old. At sexual maturity, i.e. approximately 18 weeks at 25 degrees C, the LT50 for the Floridan strain was approximately 31-8 hours; experiments with a hybrid stock of the two strains had an LT50 of 30-0 hours. Younger snails were significantly more susceptible to the molluscicide, and eggs were approximately four times more resistant than adults; this agrees with findings by previous authors for other snail species. In the case of the accidental uncontrolled spread of Marisa to cultivated areas it is suggested that a concentration of 0-03 Frescon is applied for at least four days.

[Effect of water conservancy schistosomiasis control projects combined with molluscicide to control Oncomelania hupensis snails in rivers connecting with Yangtze River in Pukou District, Nanjing City].

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Qiang, Zhou; Li-Xin, Wan; De-Rong, Hang; Qi-Hui, You; Jun, You; Yu-Lin, Zhang; Zhao-Feng, Zhu; Yi-Xin, Huang

2017-12-07

To evaluate the effect of the water conservancy schistosomiasis control projects combined with molluscicide to control Oncomelania hupensis snails in the rivers connecting with the Yangtze River. The water conservancy schistosomiasis control projects of Zhujiashan River, Qili River and Gaowang River were chosen as the study objects in Pukou District, Nanjing City. The data review method and field investigation were used to evaluate the effect of the water conservancy schistosomiasis control projects combined with molluscicide to control O. hupensis snails. After the projects of the water level control and concrete slope protection and mollusciciding were implemented, the snails in the project river sections were completely eliminated. The snail diffusion did not happen in the inland irrigation area too. In the outside of the river beach, though the snails still existed, the snail densities plunged below 1.0 snail per 1.0 m 2 . The comprehensive measures of the combination of water level control, concrete slope protection and mollusciciding can effectively control and eliminate the snails, and prevent the snails from spreading.

[Oncomelania hupensis snail distribution in working areas of Yangtze River hydrologic agencies located in middle and lower reaches of Yangtze River in 2016].

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Min, Xu; Suo-Xin, Huang; Zheng-Yuan, Zhao; Ben-Jiao, Hu; Jun, Fu; Si-Min, Dai; Li-Hong, Wen

2016-10-13

To understand the Oncomelania hupensis snail distribution in the working areas of Yangtze River hydrologic agencies located in the middle and lower reaches of the Yangtze River in 2016, so as to provide the evidence for assessing the risk of schistosome infection of hydrological workers and establishing the control strategies. The suspicious environments with O. hupensis snails in the above working areas were selected as study areas, and the snail situation was surveyed by the system sampling method combined with the environmental sampling method. The survey data were collected and analyzed statistically. Totally 19 working areas from 17 hydrological agencies were selected as the investigation sites, among which, 10 working areas from 9 agencies were found with O. hupensis snail distribution. The constituent ratio of the areas with snails reached to 38.81% of the investigation areas, the occurrence rate of frames with snails was 3.08%, and the average density of living snails was 0.07 /0.1 m 2 . By comparison, the average density of living snails and occurrence rate of frames with snails in hydrological agencies under the jurisdiction of the Middle Reaches Administrative Bureau were the most serious among three administrative bureaus of the Yangtze River Water Resources Commission. There are various degrees of O. hupensis breeding in the working areas of hydrological agencies located in the middle and lower reaches of the Yangtze River, and the hydrological workers are facing with the risk of schistosome infection.

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

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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...

Behavior of technetium in freshwater environments

Energy Technology Data Exchange (ETDEWEB)

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

1984-01-01

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

Behavior of technetium in freshwater environments

International Nuclear Information System (INIS)

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

1984-01-01

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

Snails and their trails: the multiple functions of trail-following in gastropods.

Science.gov (United States)

Ng, Terence P T; Saltin, Sara H; Davies, Mark S; Johannesson, Kerstin; Stafford, Richard; Williams, Gray A

2013-08-01

Snails are highly unusual among multicellular animals in that they move on a layer of costly mucus, leaving behind a trail that can be followed and utilized for various purposes by themselves or by other animals. Here we review more than 40 years of experimental and theoretical research to try to understand the ecological and evolutionary rationales for trail-following in gastropods. Data from over 30 genera are currently available, representing a broad taxonomic range living in both aquatic and terrestrial environments. The emerging picture is that the production of mucus trails, which initially was an adaptation to facilitate locomotion and/or habitat extension, has evolved to facilitate a multitude of additional functions. Trail-following supports homing behaviours, and provides simple mechanisms for self-organisation in groups of snails, promoting aggregation and thus relieving desiccation and predation pressures. In gastropods that copulate, trail-following is an important component in mate-searching, either as an alternative, or in addition to the release of water- or air-borne pheromones. In some species, this includes a capacity of males not only to identify trails of conspecifics but also to discriminate between trails laid by females and males. Notably, trail discrimination seems important as a pre-zygotic barrier to mating in some snail species. As production of a mucus trail is the most costly component of snail locomotion, it is also tempting to speculate that evolution has given rise to various ways to compensate for energy losses. Some snails, for example, increase energy intake by eating particles attached to the mucus of trails that they follow, whereas others save energy through reducing the production of their own mucus by moving over previously laid mucus trails. Trail-following to locate a prey item or a mate is also a way to save energy. While the rationale for trail-following in many cases appears clear, the basic mechanisms of trail

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

Science.gov (United States)

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

2013-11-01

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

Utilization of the invasive plant Impatiens parviflora DC. by the snail Columella edentula Draparnaud in oak-hornbeam forests

Directory of Open Access Journals (Sweden)

Renata Piskorz

2011-01-01

Full Text Available This study investigated the extend to which the snail Columella edentula is more strongly associated with the small balsam Impatiens parviflora than with other plants in the herb layer of an oak-hornbeam forest, and to interpret the character of the interaction Impatiens parviflora - Columella edentula. Numbers of C. edentula and rates of colonization were compared on various plant species under natural and laboratory conditions. Seasonal variation in snail abundance on I. parviflora was observed on permanent plots. The leaf injuries caused by C. edentula were localized in respect of the morphological and anatomical structure of leaves. The results show that I. parviflora is one of the plant species of the herb layer that are most abundantly colonized by this snail in oak-hornbeam forest. Snail finds a plant particularly suitable as a place for resting. The most favoured attachment site is on the underside of the leaf, along the midrib, which provides the highest and relatively stable humidity, as well as protection from direct sunlight and predators. I. parviflora is also a food for the snails, but they do not eat these fragments of leaves where calcium carbonate is accumulated.

Predation as the primary selective force in recurrent evolution of gigantism in Poecilozonites land snails in Quaternary Bermuda

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Olson, Storrs L.; Hearty, Paul J.

2010-01-01

During the last half million years, pulses of gigantism in the anagenetic lineage of land snails of the subgenus Poecilozonites on Bermuda were correlated with glacial periods when lower sea level resulted in an island nearly an order of magnitude larger than at present. During those periods, the island was colonized by large vertebrate predators that created selection pressure for large size and rapid growth in the snails. Extreme reduction in land area from rising seas, along with changes in ecological conditions at the onset of interglacial episodes, marked extinction events for large predators, after which snails reverted to much smaller size. The giant snails were identical in morphology during the last two glacials when the predators included a large flightless rail Rallus recessus (marine isotope stages (MIS) 4-2) and a crane Grus latipes and a duck Anas pachysceles (MIS 6). In a preceding glacial period (MIS 10), when the fauna also included the tortoise Hesperotestudo bermudae, the snails were not only large, but the shells were much thicker, presumably to prevent crushing by tortoises. Evolution of Poecilozonites provides an outstanding example of dramatic morphological change in response to environmental pressures in the absence of cladogenesis. PMID:20554560

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

Science.gov (United States)

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

2005-01-01

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

[Comparison study on sampling methods of Oncomelania hupensis snail survey in marshland schistosomiasis epidemic areas in China].

Science.gov (United States)

An, Zhao; Wen-Xin, Zhang; Zhong, Yao; Yu-Kuan, Ma; Qing, Liu; Hou-Lang, Duan; Yi-di, Shang

2016-06-29

To optimize and simplify the survey method of Oncomelania hupensis snail in marshland endemic region of schistosomiasis and increase the precision, efficiency and economy of the snail survey. A quadrate experimental field was selected as the subject of 50 m×50 m size in Chayegang marshland near Henghu farm in the Poyang Lake region and a whole-covered method was adopted to survey the snails. The simple random sampling, systematic sampling and stratified random sampling methods were applied to calculate the minimum sample size, relative sampling error and absolute sampling error. The minimum sample sizes of the simple random sampling, systematic sampling and stratified random sampling methods were 300, 300 and 225, respectively. The relative sampling errors of three methods were all less than 15%. The absolute sampling errors were 0.221 7, 0.302 4 and 0.047 8, respectively. The spatial stratified sampling with altitude as the stratum variable is an efficient approach of lower cost and higher precision for the snail survey.

Spread of the Rat Lungworm (Angiostrongylus cantonensis) in Giant African Land Snails (Lissachatina fulica) in Florida, USA.

Science.gov (United States)

Iwanowicz, Deborah D; Sanders, Lakyn R; Schill, W Bane; Xayavong, Maniphet V; da Silva, Alexandre J; Qvarnstrom, Yvonne; Smith, Trevor

2015-07-01

The rat lungworm (Angiostrongylus cantonensis) is a parasitic nematode that causes rat lungworm disease. It is the leading cause of eosinophilic meningitis and is a zoonotic health risk. We confirmed the presence of A. cantonensis using species-specific, quantitative PCR in 18 of 50 (36%) giant African land snails (Lissachatina fulica) collected from Miami, Florida, US in May 2013. These snails were collected from seven of 21 core areas that the Florida Department of Agriculture and Consumer Services monitor weekly. Rat lungworms have not previously been identified in these areas. Duplicate DNA extractions of foot muscle tissue from each snail were tested. Of the seven core areas we examined, six were positive for A. cantonensis and prevalence of infection ranged from 27% to 100%. Of the 18 positive snails, only five were positive in both extractions. Our results confirm an increase in the range and prevalence of rat lungworm infection in Miami. We also emphasize the importance of extracting sufficient host tissue to minimize false negatives.

Epithelial-mesenchymal transition in breast epithelial cells treated with cadmium and the role of Snail.

Science.gov (United States)

Wei, Zhengxi; Shan, Zhongguo; Shaikh, Zahir A

2018-04-01

Epidemiological and experimental studies have implicated cadmium (Cd) with breast cancer. In breast epithelial MCF10A and MDA-MB-231 cells, Cd has been shown to promote cell growth. The present study examined whether Cd also promotes epithelial-mesenchymal transition (EMT), a hallmark of cancer progression. Human breast epithelial cells consisting of non-cancerous MCF10A, non-metastatic HCC 1937 and HCC 38, and metastatic MDA-MB-231 were treated with 1 or 3 μM Cd for 4 weeks. The MCF10A epithelial cells switched to a more mesenchymal-like morphology, which was accompanied by a decrease in the epithelial marker E-cadherin and an increase in the mesenchymal markers N-cadherin and vimentin. In both non-metastatic HCC 1937 and HCC 38 cells, treatment with Cd decreased the epithelial marker claudin-1. In addition, E-cadherin also decreased in the HCC 1937 cells. Even the mesenchymal-like MDA-MB-231 cells exhibited an increase in the mesenchymal marker vimentin. These changes indicated that prolonged treatment with Cd resulted in EMT in both normal and cancer-derived breast epithelial cells. Furthermore, both the MCF10A and MDA-MB-231 cells labeled with Zcad, a dual sensor for tracking EMT, demonstrated a decrease in the epithelial marker E-cadherin and an increase in the mesenchymal marker ZEB-1. Treatment of cells with Cd significantly increased the level of Snail, a transcription factor involved in the regulation of EMT. However, the Cd-induced Snail expression was completely abolished by actinomycin D. Luciferase reporter assay indicated that the expression of Snail was regulated by Cd at the promotor level. Snail was essential for Cd-induced promotion of EMT in the MDA-MB-231 cells, as knockdown of Snail expression blocked Cd-induced cell migration. Together, these results indicate that Cd promotes EMT in breast epithelial cells and does so by modulating the transcription of Snail. Copyright © 2018 Elsevier Inc. All rights reserved.

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

Science.gov (United States)

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.

First report of Angiostrongylus cantonensis in the giant African land snail Achatina fulica in French Polynesia detected using the SSU rRNA gene.

Science.gov (United States)

Fontanilla I, K C; Wade, C M

2012-12-01

The 5' end of the small subunit ribosomal RNA gene was used to determine whether 3rd larval stage Angiostrongylus cantonensis are present in populations of the giant African land snail Achatina fulica from French Polynesia. Two populations, one from Moaroa Valley, Tahiti (n=5) and the other from Haapiti Valley, Moorea (n=10), were examined. All snails from Tahiti were infected with nematodes, with parasite load ranging from 12 to 28. A total of 92 nematodes were found, of which 91 were positively identified as A. cantonensis. No nematodes were found in the snails from Moorea. We report for the first time the presence of A. cantonensis in A. fulica snails from French Polynesia, indicating a viable route of human infection of A. cantonensis in the region through the handling of A. fulica or consumption of the snail or contaminated food crops associated with the snail.

Implications of Changing Temperatures on the Growth, Fecundity and Survival of Intermediate Host Snails of Schistosomiasis: A Systematic Review

Directory of Open Access Journals (Sweden)

Chester Kalinda

2017-01-01

Full Text Available Climate change has been predicted to increase the global mean temperature and to alter the ecological interactions among organisms. These changes may play critical roles in influencing the life history traits of the intermediate hosts (IHs. This review focused on studies and disease models that evaluate the potential effect of temperature rise on the ecology of IH snails and the development of parasites within them. The main focus was on IH snails of schistosome parasites that cause schistosomiasis in humans. A literature search was conducted on Google Scholar, EBSCOhost and PubMed databases using predefined medical subject heading terms, Boolean operators and truncation symbols in combinations with direct key words. The final synthesis included nineteen published articles. The studies reviewed indicated that temperature rise may alter the distribution, optimal conditions for breeding, growth and survival of IH snails which may eventually increase the spread and/or transmission of schistosomiasis. The literature also confirmed that the life history traits of IH snails and their interaction with the schistosome parasites are affected by temperature and hence a change in climate may have profound outcomes on the population size of snails, parasite density and disease epidemiology. We concluded that understanding the impact of temperature on the growth, fecundity and survival of IH snails may broaden the knowledge on the possible effects of climate change and hence inform schistosomiasis control programmes.

Susceptibility of the Giant African snail (Achatina fulica) exposed to the gastropod parasitic nematode Phasmarhabditis hermaphrodita.

Science.gov (United States)

Williams, A J; Rae, R

2015-05-01

The Giant African snail (Achatina fulica) is a major pest in tropical countries. Current control methods involve the use of slug pellets (metaldehyde) but they are ineffective, therefore new methods of control are needed. We investigated whether A. fulica is susceptible to the gastropod parasitic nematode Phasmarhabditis hermaphrodita, which has been developed as a biological control agent for slugs and snails in northern Europe. We exposed A. fulica to P. hermaphrodita applied at 30 and 150nematodes per cm(2) for 70days and also assessed feeding inhibition and changes in snail weight. We show that unlike the susceptible slug species Deroceras panormitanum, which is killed less than 30days of exposure to P. hermaphrodita, A. fulica is remarkably resistant to the nematode at both doses. Also P. hermaphrodita does not reduce feeding in A. fulica nor did it have any effect on weight gain over 70days. Upon dissection of infected A. fulica we found that hundreds of P. hermaphrodita had been encapsulated, trapped and killed in the snail's shell. We found that A. fulica is able to begin encapsulating P. hermaphrodita after just 3days of exposure and the numbers of nematodes encapsulated increased over time. Taken together, we have shown that A. fulica is highly resistant to P. hermaphrodita, which could be due to an immune response dependent on the snail shell to encapsulate and kill invading parasitic nematodes. Copyright © 2015 Elsevier Inc. All rights reserved.

Effect of cysteine and humic acids on bioavailability of Ag from Ag nanoparticles to a freshwater snail

Science.gov (United States)

Luoma, Samuel N.; Tasha Stoiber,; Croteau, Marie-Noele; Isabelle Romer,; Ruth Merrifeild,; Lead, Jamie

2016-01-01

Metal-based engineered nanoparticles (NPs) will undergo transformations that will affect their bioavailability, toxicity and ecological risk when released to the environment, including interactions with dissolved organic material. The purpose of this paper is to determine how interactions with two different types of organic material affect the bioavailability of silver nanoparticles (AgNPs). Silver uptake rates by the pond snail Lymnaea stagnalis were determined after exposure to 25 nmol l-1 of Ag as PVP AgNPs, PEG AgNPs or AgNO3, in the presence of either Suwannee River humic acid or cysteine, a high-affinity thiol-rich organic ligand. Total uptake rate of Ag from the two NPs was either increased or not strongly affected in the presence of 1 – 10 mg 1-1 humic acid. Humic substances contain relatively few strong ligands for Ag explaining their limited effects on Ag uptake rate. In contrast, Ag uptake rate was substantially reduced by cysteine. Three components of uptake from the AgNPs were quantified in the presence of cysteine using a biodynamic modeling approach: uptake of dissolved Ag released by the AgNPs, uptake of a polymer or large (>3kD) Ag-cysteine complex and uptake of the nanoparticle itself. Addition of 1:1 Ag:cysteine reduced concentrations of dissolved Ag, which contributed to, but did not fully explain the reductions in uptake. A bioavailable Ag-cysteine complex (> 3kD) appeared to be the dominant avenue of uptake from both PVP AgNPs and PEG AgNPs in the presence of cysteine. Quantifying the different avenues of uptake sets the stage for studies to assess toxicity unique to NPs.

Characterization of South American Snails of the Genus Biomphalaria (Basommatophora: Planorbidae and Schistosoma mansoni (Platyhelminthes: Trematoda in Molluscs by PCR-RFLP

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Roberta Lima Caldeira

2016-01-01

Full Text Available The identification of snails of the genus Biomphalaria can be done using morphological characteristics which depends on the size of the snails and skill and knowledge of researcher. These methods sometimes are not adequate for identification of species. The PCR-RFLP, using the ITS region of the rDNA, has been used to identify Brazilian species of the genus Biomphalaria. Nevertheless, there is a lack of information about snails from other Latin American countries. In addition, some snails may be infected by Schistosoma mansoni and when submitted to PCR-RFLP they show molecular profiles different from those previously standardized for the other mollusc species. In this work the molecular profiles of 15 species and the subspecies were established by PCR-RFLP of ITS-rDNA with the enzyme DdeI. Moreover, the molecular profiles of host species, B. glabrata, B. straminea, B. tenagophila, and B. prona, infected by S. mansoni were also established. The molluscs were dissected to permit morphological identification. These results contribute to a correct identification of snails of the genus Biomphalaria and detection of these snails infected by S. mansoni.

Distribution of intermediate host snails of schistosomiasis and fascioliasis in relation to environmental factors during the dry season in the Tchologo region, Côte d'Ivoire

Science.gov (United States)

Krauth, Stefanie J.; Wandel, Nathalie; Traoré, Seïdinan I.; Vounatsou, Penelope; Hattendorf, Jan; Achi, Louise Y.; McNeill, Kristopher; N'Goran, Eliézer K.; Utzinger, Jürg

2017-10-01

Snail-borne trematodiases, such as fascioliasis and schistosomiasis, belong to the neglected tropical diseases; yet, millions of people and livestock are affected. The spatial and temporal distribution of intermediate host snails plays an important role in the epidemiology and control of trematodiases. Snail distribution is influenced by numerous environmental and anthropomorphic factors. The aim of this study was to assess the distribution and constitution of the snail fauna during the dry season in constructed and natural water bodies in the Tchologo region, northern Côte d'Ivoire, and to relate these findings to environmental factors and human infections. Snails were collected using standard procedures and environmental parameters were assessed from a total of 50 water bodies in and around 30 randomly selected villages. A canonical correspondence analysis was performed to establish the relationship between snail occurrence and environmental factors. Furthermore, a total of 743 people from the same 30 villages and nearby settlements were invited for stool and urine examination for the diagnosis of Fasciola spp., Schistosoma haematobium and Schistosoma mansoni. Snails of medical importance of the genera Biomphalaria, Bulinus, Lymnaea and Physa were found. Differences in snail occurrence from sites sampled in December 2014 and snails sampled in February 2015, as well as between the northern and southern part of the study area, were revealed. Various environmental factors, such as temperature and human activities, were related to the occurrence of intermediate host snail species in the region. Only 2.3% of human participants tested positive for schistosomiasis, while no Fasciola eggs were found in stool samples. We conclude that intermediate host snails of Fasciola and Schistosoma co-occur in water bodies in the Tchologo region and that the distribution of these snails correlates not only with environmental factors, but also with the presence of humans and animals

Ecology and distribution of gastropod snails of medical and ...

African Journals Online (AJOL)

A study on the ecology and distribution of snails of medical importance was conducted in water bodies from four different communities (Old Karmo, Gwagwa, ... The following floras were identified from the study-sites; Megathyrsus maximus, Guinea grass and Commelina nigritana (African dayflower) were identified from the ...

Spatially-resolved thermoluminescence from snail opercula using an EMCCD

DEFF Research Database (Denmark)

Duller, G.A.T.; Kook, Myung Ho; Stirling, R.J.

2015-01-01

In recent years opercula of the snail species Bithynia tentaculata have been shown to emit thermoluminescence (TL) signals that can be used to determine equivalent dose, and may be capable of dating events throughout the entire Quaternary period. Concentric growth lines are a notable feature of a...

Freshwater Fungal Infections

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Dennis J. Baumgardner

2017-01-01

Full Text Available Fungal infections as a result of freshwater exposure or trauma are fortunately rare. Etiologic agents are varied, but commonly include filamentous fungi and Candida. This narrative review describes various sources of potential freshwater fungal exposure and the diseases that may result, including fungal keratitis, acute otitis externa and tinea pedis, as well as rare deep soft tissue or bone infections and pulmonary or central nervous system infections following traumatic freshwater exposure during natural disasters or near-drowning episodes. Fungal etiology should be suspected in appropriate scenarios when bacterial cultures or molecular tests are normal or when the infection worsens or fails to resolve with appropriate antibacterial therapy.

Metagonimoides oregonensis (Heterophyidae:Digenea) Infection in pleurocerid snails and Desmognathus quadramaculatus salamander larvae in southern Appalachian streams

Science.gov (United States)

Lisa K. Belden; William E. Peterman; Stephen A. Smith; Lauren R. Brooks; E.F. Benfield; Wesley P. Black; Zhaomin Yang; Jeremy M. Wojdak

2012-01-01

Metagonimoides oregonensis (Heterophyidae) is a little-known digenetic trematode that uses raccoons and possibly mink as definitive hosts, and stream snails and amphibians as intermediate hosts. Some variation in the life cycle and adult morphology in western and eastern populations has been previously noted. In the southern Appalachians, Pleurocera snails and stream...

Characterization of gelatin/chitosan scaffold blended with aloe vera and snail mucus for biomedical purpose.

Science.gov (United States)

López Angulo, Daniel Enrique; do Amaral Sobral, Paulo José

2016-11-01

Biologically active scaffolds used in tissue engineering and regenerative medicine have been generating promising results in skin replacement. The present study aims to test the hypothesis that the incorporation of Aloe vera and snail mucus into scaffolds based on gelatin and chitosan could improve their structure, composition and biodegradability, with a potential effect on bioactivity. Homogeneous pore diameter as well as pore walls in the composite scaffold could be seen in the SEM image. The pores in the scaffolds were interconnected and their sizes ranged from 93 to 296μm. The addition of Aloe vera and snail mucus enlarged the mean pore size with increased porosity and caused changes in the pore architecture. The FTIR analysis has shown good affinity and interaction between the matrix and the Aloe, which may decrease water-binding sites, so this fact hindered the water absorption capacity of the material. The mechanical properties could explain the highest swelling capacity of the snail scaffold, because the high percentage of elongation could facilitate the entry of liquid in it, generating a matrix with plenty of fluid retention. The real innovation in the present work could be the use of these substances (Aloe and snail mucus) for tissue engineering. Copyright © 2016 Elsevier B.V. All rights reserved.

A checklist of land snails from the west coast islands of Sabah, Borneo (Mollusca, Gastropoda

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Chee-Chean Phung

2017-05-01

Full Text Available Sabah, situated in one of the world’s biodiversity hotspots, has the largest number of islands in Malaysia with more than 500 of various sizes and degrees of isolation. However, information on the islands’ biodiversity is limited. This study provides an up-to-date checklist of land snail species found on 24 west coast islands in Sabah. A total of 67 species (nearly 20% of the total number of land snail species in the state representing 37 genera and 19 families is enumerated based on systematic field surveys of 133 sampling plots, BORNEENSIS database records and species checklists published between 2000 and 2016. The number of species on the islands ranges from four to 29. Labuan Island has the highest number of species (29, followed by Tiga Island (25, Mantanani Besar Island (24 and Gaya Island (23. However, the populations of some land snail species may have declined as several previously recorded species on the islands were not found in a recent systematic field sampling. This checklist is provided as a baseline inventory for future island land snail studies and to better inform biodiversity conservation plans of marine parks and other islands on the Sabah west coast.

The Compatibility Between Biomphalaria glabrata Snails and Schistosoma mansoni: An Increasingly Complex Puzzle.

Science.gov (United States)

Mitta, G; Gourbal, B; Grunau, C; Knight, M; Bridger, J M; Théron, A

2017-01-01

This review reexamines the results obtained in recent decades regarding the compatibility polymorphism between the snail, Biomphalaria glabrata, and the pathogen, Schistosoma mansoni, which is one of the agents responsible for human schistosomiasis. Some results point to the snail's resistance as explaining the incompatibility, while others support a "matching hypothesis" between the snail's immune receptors and the schistosome's antigens. We propose here that the two hypotheses are not exclusive, and that the compatible/incompatible status of a particular host/parasite couple probably reflects the balance of multiple molecular determinants that support one hypothesis or the other. Because these genes are involved in a coevolutionary arms race, we also propose that the underlying mechanisms can vary. Finally, some recent results show that environmental factors could influence compatibility. Together, these results make the compatibility between B. glabrata and S. mansoni an increasingly complex puzzle. We need to develop more integrative approaches in order to find targets that could potentially be manipulated to control the transmission of schistosomiasis. Copyright © 2017 Elsevier Ltd. All rights reserved.

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

Science.gov (United States)

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.

Deshayes, 1834

African Journals Online (AJOL)

SARAH

30 nov. 2013 ... “No correlation between inbreeding depression and delayed selfing in the freshwater snail. Physa acuta”. Évolution 61:2655–2670. Henry P. Y., Bousset L., Sourrouille P., & Jarne P.,. 2005. “Partial selfing, ecological disturbance and reproductive assurance in an invasive freshwater snail”. Heredity, 95, pp ...

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

Science.gov (United States)

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

1997-06-01

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

Snail family members unequally trigger EMT and thereby differ in their ability to promote the neoplastic transformation of mammary epithelial cells.

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Baptiste Gras

Full Text Available By fostering cell commitment to the epithelial-to-mesenchymal transition (EMT, SNAIL proteins endow cells with motility, thereby favoring the metastatic spread of tumor cells. Whether the phenotypic change additionally facilitates tumor initiation has never been addressed. Here we demonstrate that when a SNAIL protein is ectopically produced in non-transformed mammary epithelial cells, the cells are protected from anoikis and proliferate under low-adherence conditions: a hallmark of cancer cells. The three SNAIL proteins show unequal oncogenic potential, strictly correlating with their ability to promote EMT. SNAIL3 especially behaves as a poor EMT-inducer comforting the concept that the transcription factor functionally diverges from its two related proteins.

Utilisation of Giant African snail (Achatina fulica) meal as protein source by laying hens

OpenAIRE

Diarra, Siaka Seriba; Kant, Rashmi; Tanhimana, Jemarlyn; Lela, Patrick

2015-01-01

A 12-week experiment was carried out to investigate the effects of substituting Giant African snail meal for fish meal in laying hens diet. Four diets were formulated to contain snail meal as replacement for fish meal at 0 (control), 33, 67 and 100%. A total of 120 Shaver Brown pullets aged 18 weeks were allocated to the dietary treatments in a randomised design. Each treatment consisted of three replicates and ten birds per replicate. Feed intake increased only for the 33% treatment as compa...

Management of shells of giant African snails (Achatinidae) from the ...

African Journals Online (AJOL)

SARAH

2014-12-01

Dec 1, 2014 ... Thus, to optimize the use of snail's shells in areas such as agricultural production ... The data collected focused on (1) stakeholders marketing system of the ... gathered was used to establish the general sales channel from the ...

Determination of 3-O- and 4-O-methylated monosaccharide constituents in snail glycans.

Science.gov (United States)

Stepan, Herwig; Bleckmann, Christina; Geyer, Hildegard; Geyer, Rudolf; Staudacher, Erika

2010-07-02

The N- and O-glycans of Arianta arbustorum, Achatina fulica, Arion lusitanicus and Planorbarius corneus were analysed for their monosaccharide pattern by reversed-phase HPLC after labelling with 2-aminobenzoic acid or 3-methyl-1-phenyl-2-pyrazolin-5-one and by gas chromatography-mass spectrometry. Glucosamine, galactosamine, mannose, galactose, glucose, fucose and xylose were identified. Furthermore, three different methylated sugars were detected: 3-O-methyl-mannose and 3-O-methyl-galactose were confirmed to be a common snail feature; 4-O-methyl-galactose was detected for the first time in snails. Copyright 2010 Elsevier Ltd. All rights reserved.

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

Energy Technology Data Exchange (ETDEWEB)

Kang, Hyereen; Lee, Minjae [Department of Biomedical Sciences, University of Ulsan College of Medicine, Seoul 138-736 (Korea, Republic of); Jang, Sung-Wuk, E-mail: swjang@amc.seoul.kr [Department of Biomedical Sciences, University of Ulsan College of Medicine, Seoul 138-736 (Korea, Republic of); Department of Biochemistry and Molecular Biology, University of Ulsan College of Medicine, Seoul 138-736 (Korea, Republic of)

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.

Elemental compositions of crab and snail shells from the Kueishantao hydrothermal field in the southwestern Okinawa Trough

Science.gov (United States)

Zeng, Zhigang; Ma, Yao; Wang, Xiaoyuan; Chen, Chen-Tung Arthur; Yin, Xuebo; Zhang, Suping; Zhang, Junlong; Jiang, Wei

2018-04-01

To reveal differences in the behavior of benthic vent animals, and the sources and sinks of biogeochemical and fluid circulations, it is necessary to constrain the chemical characteristics of benthic animals from seafloor hydrothermal fields. We measured the abundances of 27 elements in shells of the crab Xenograpsus testudinatus and the snail Anachis sp., collected from the Kueishantao hydrothermal field (KHF) in the southwestern Okinawa Trough, with the aim of improving our understanding of the compositional variations between individual vent organisms, and the sources of the rare earth elements (REEs) in their shells. The Mn, Hg, and K concentrations in the male X. testudinatus shells are found to be higher than those in female crab shells, whereas the reverse is true for the accumulation of B, implying that the accumulation of K, Mn, Hg, and B in the crab shells is influenced by sex. This is inferred to be a result of the asynchronous molting of the male and female crab shells. Snail shells are found to have higher Ca, Al, Fe, Ni, and Co concentrations than crab shells. This may be attributed to different metal accumulation times. The majority of the light rare earth element (LREE) distribution patterns in the crab and snail shells are similar to those of Kueishantao vent fluids, with the crab and snail shells also exhibiting LREE enrichment, implying that the LREEs contained in crab and snail shells in the KHF are derived from vent fluids.

Domain analysis of the Nematostella vectensis SNAIL ortholog reveals unique nucleolar localization that depends on the zinc-finger domains

NARCIS (Netherlands)

Dattoli, A.A.; Hink, M.A.; DuBuc, T.Q.; Teunisse, B.J.; Goedhart, J.; Röttinger, E.; Postma, M.

2015-01-01

SNAIL transcriptional factors are key regulators during development and disease. They arose early during evolution, and in cnidarians such as Nematostella vectensis, NvSNAILA/B are detected in invaginating tissues during gastrulation. The function of SNAIL proteins is well established in bilaterians

Novel animal defenses against predation: a snail egg neurotoxin combining lectin and pore-forming chains that resembles plant defense and bacteria attack toxins.

Directory of Open Access Journals (Sweden)

Marcos Sebastián Dreon

Full Text Available 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

Combined detection of Twist1, Snail1 and squamous cell carcinoma antigen for the prognostic evaluation of invasion and metastasis in cervical squamous cell carcinoma.

Science.gov (United States)

Yang, Huilun; Hu, Haiyang; Gou, Yanling; Hu, Yuhong; Li, Hui; Zhao, Hongwei; Wang, Beidi; Li, Peiling; Zhang, Zongfeng

2018-04-01

Cervical cancer is one of the most common malignant tumours of the female reproductive system, ranking second only to breast cancer in morbidity worldwide. Essential features of the progression of cervical cancer are invasion and metastasis, which are closely related to disease prognosis and mortality rate. At the present time there is no effective method to evaluate cancer invasion and metastasis before surgery. Here we report our study on molecular changes in biopsy tissue for the prognostic evaluation of cancer invasion and metastasis. Expression of the epithelial-mesenchymal transition-inducing transcription factors Twist1 and Snail1 was detected by immunohistochemistry in 32 normal, 36 low-grade squamous intraepithelial neoplasia (LSIL), 54 high-grade squamous intraepithelial neoplasia (HSIL) and 320 cervical squamous cell carcinoma (CSCC) samples. The correlation between the expression of Twist1, Snail1 and squamous cell carcinoma antigen (SCCA) in CSCC tissues and clinical pathology results was evaluated. A transwell migration and invasion assay was used to explore the roles of Twist1 and Snail1 in the invasion of cancer cells. Lymph node metastasis and lymphovascular space invasion (LVSI) rates for the following groups were analysed: SCCA(+) group, Twist1(+) group, Snail1(+) group, Twist1(+)Snail1(+)group, Twist1(+)SCCA(+)group, Snail1(+)SCCA(+)group and Twist1(+)Snail1(+)SCCA(+) group. The expression of Twist1 and Snail1 was significantly upregulated in HSIL and CSCC (p  0.05). The expression of SCCA was associated with LVSI, lymph node metastasis, FIGO stage and histological grade (p  0.05). Twist1 was an independent factor contributing to the invasion ability of cervical cancer cells. In addition, the positive rate of lymph node metastasis and LVSI was higher in the Twist1(+)Snail1(+)SCCA(+) group than in the SCCA(+) group, Twist1(+) group and Snail1(+) group, respectively (p < 0.05). Combined detection of Twist1 and Snail1 in SCCA-positive biopsy

Detection of early and single infections of Schistosoma japonicum in the intermediate host snail, Oncomelania hupensis, by PCR and loop-mediated isothermal amplification (LAMP) assay.

Science.gov (United States)

Kumagai, Takashi; Furushima-Shimogawara, Rieko; Ohmae, Hiroshi; Wang, Tian-Ping; Lu, Shaohong; Chen, Rui; Wen, Liyong; Ohta, Nobuo

2010-09-01

Polymerase chain reaction (PCR) with the specific primer set amplifying 28S ribosomal DNA (rDNA) of Schistosoma japonicum was able to detect genomic DNA of S. japonicum, but not S. mansoni, at 100 fg. This procedure enabled us to detect the DNA from a single miracidium and a snail infected with one miracidium at just 1 day after infection. We compared these results with those from loop-mediated isothermal amplification (LAMP) targeting 28S rDNA and found similar results. The LAMP could amplify the specific DNA from a group of 100 normal snails mixed with one infected snail A PCR screening of infected snails from endemic regions in Anhui Province revealed schistosomal DNA even in snails found negative by microscopy. PCR and LAMP show promise for monitoring the early infection rate in snails, and they may be useful for predicting the risk of infection in the endemic places.

The potential for using red claw crayfish and hybrid African catfish as biological control agents for Schistosoma host snails

NARCIS (Netherlands)

Monde, C.; Syampungani, S.; Rico, A.; Brink, van den P.J.

2017-01-01

The potential of red claw crayfish and hybrid African catfish (Clarias gariepinus and Clarias ngamensis) as predators for Schistosoma host snails was evaluated in 2014 by monitoring the consumption of snails by crayfish and catfish in experimental tanks over time under laboratory conditions. After

[Study of spatial stratified sampling strategy of Oncomelania hupensis snail survey based on plant abundance].

Science.gov (United States)

Xun-Ping, W; An, Z

2017-07-27

Objective To optimize and simplify the survey method of Oncomelania hupensis snails in marshland endemic regions of schistosomiasis, so as to improve the precision, efficiency and economy of the snail survey. Methods A snail sampling strategy (Spatial Sampling Scenario of Oncomelania based on Plant Abundance, SOPA) which took the plant abundance as auxiliary variable was explored and an experimental study in a 50 m×50 m plot in a marshland in the Poyang Lake region was performed. Firstly, the push broom surveyed data was stratified into 5 layers by the plant abundance data; then, the required numbers of optimal sampling points of each layer through Hammond McCullagh equation were calculated; thirdly, every sample point in the line with the Multiple Directional Interpolation (MDI) placement scheme was pinpointed; and finally, the comparison study among the outcomes of the spatial random sampling strategy, the traditional systematic sampling method, the spatial stratified sampling method, Sandwich spatial sampling and inference and SOPA was performed. Results The method (SOPA) proposed in this study had the minimal absolute error of 0.213 8; and the traditional systematic sampling method had the largest estimate, and the absolute error was 0.924 4. Conclusion The snail sampling strategy (SOPA) proposed in this study obtains the higher estimation accuracy than the other four methods.

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

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

Factors controlling carbon isotopic composition of land snail shells estimated from lab culturing experiment

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Zhang, Naizhong; Yamada, Keita; Yoshida, Naohiro

2014-05-01

Carbon isotopic composition (δ13C) of land snail shell carbonate is widely applied in reconstructing the C3/C4 vegetation distribution of paleo-environment, which is considered to reflect variations of some environmental parameters [1][2][3]. Land snail shell carbon has three potential sources: diet, atmospheric CO2 and ingested carbonate (limestone) [4]. However, their relative contributions to shell carbonate have not been understood well yet [4][5][6][7][8]. More researches are necessary before we could apply this tool in paleo-environment reconstruction, especially inter-lab culturing experiment. A kind of land snail species, Acusta despecta sieboldiana, was collected at Yokohama, Japan and cultured under suitable environment to lay eggs. The second generations were growing up from eggs to adults around 6-12 months at the temperature of 20°, 25° and 30°, respectively. All of the snails at 25° and 30° and most of those at 20° were fed by cabbage (C3 plant) during their life span while others were fed by corn (C4 plant). To investigate the effect of ingested carbonate, some of them were fed by Ca3(PO4)2 powder while others were fed by CaCO3 powder. δ13C of shells were analyzed by an Isotope Ratio Mass Spectrometry (Thermo Finnigan MAT 253); δ13C of food and snail tissue were measured by a Cavity Ring-Down Spectroscopy (Picarro G1121-i). At the same time, δ13C of eggshell and new born snails were analyzed by a Continuous Flow Isotope Ratio Mass Spectrometry (GasBench II). We confirmed that diet, atmospheric CO2 and ingested limestone could be important sources controlling shell δ13C values. And the temperature could affect shell carbonate δ13C values, too. A simple but credible frame was raised to discuss the mechanism of how each possible source and environmental parameter could affect shell carbonate δ13C values based on previous works [4][6][8] and this study. According to this frame and some reasonable assumptions, we have estimated the

Alterations in the fatty acid profile, antioxidant enzymes and protein pattern of Biomphalaria alexandrina snails exposed to the pesticides diazinon and profenfos.

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

2016-04-01

The use of pesticides is widespread in agricultural activities. These pesticides may contaminate the irrigation and drainage systems during agriculture activities and pests' control and then negatively affect the biotic and a biotic component of the polluted water courses. The present study aimed to evaluate the effect of the pesticides diazinon and profenfos on some biological activities of Biomphalaria alexandrina snails such as fatty acid profile, some antioxidant enzymes (thioredoxin reductase (TrxR), sorbitol dehydrogenase (SDH), superoxide dismutase (SOD), catalase (CAT) as well as glutathione reductase (GR) and lipid peroxidation (LP)) and protein patterns in snails' tissues exposed for 4 weeks to LC10 of diazinon and profenfos. The results showed that the two pesticides caused considerable reduction in survival rates and egg production of treated snails. Identification of fatty acid composition in snail tissues treated with diazinon and profenfos pesticides was carried out using gas-liquid chromatography (GLC). The results declared alteration in fatty acid profile, fluctuation in percentage of long chain and short chain fatty acid contributions either saturated or unsaturated ones, and a decrease in total lipid content in tissues of snails treated with these pesticides. The data demonstrate that there was a significant inhibition in the activities of tissues SOD, CAT, glutathione reductase (GR), TrxR, and SDH in tissues of treated snails, while a significant elevation was detected in LP as compared to the normal control. On the other hand, the electrophoretic pattern of total protein showed differences in number and molecular weights of protein bands due to the treatment of snails. It was concluded that the residues of diazinon and profenfos pesticides in aquatic environments have toxic effects onB. alexandrina snails. © The Author(s) 2013.

The role of snail aestivation in transmission of schistosomiasis in ...

African Journals Online (AJOL)

Aestivation therefore plays an important role in maintaining the transmission of schistosomiasis. This review assesses the possible impacts of climate change on the temporal and spatial distribution of schistosomiasis-transmitting snails with special emphasis on aestivation, and discusses the effect of schistosome infection ...

Differences in predatory pressure on terrestrial snails by birds and ...

Indian Academy of Sciences (India)

Supplementary table 2. Number of collected individuals of particular morph categories of C. nemoralis and C. hortensis with specification of undamaged and damaged snails. Morph. Total number of individuals. Undamaged individuals. Shells damaged by. Mice. Birds. Mouse + bird. Cepaea nemoralis. 732. 172. 105. 436.

Speciation and gene flow between snails of opposite chirality.

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Angus Davison

2005-09-01

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

Effects of climatic factors on prevalence of developmental stages of Fasciola gigantica infection in Lymnaea snails (Lymnaea auricularia var rufescens in Bangladesh

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Islam, K.M

2015-10-01

Full Text Available The present study was conducted to investigate the prevalence of developmental stages of Fasciola gigantica infection in Lymnaea snails and their populations in Sylhet region of Bangladesh. A total of 1865 Lymnaea snails were collected and examined, of which 56 (3% were found to having infected with developmental stages of Fasciola gigantica. Only 4.08% infected of 515 snails were collected from Biswanath Upazilla followed by 3.16% of 443 from Beanibazar, 2.53% of 396 from Balaganj then 2.40% of 292 Jaintapur Upazilla and the lowest 1.83% of 219 from Sylhet Sadar. Month-wise data, the prevalence of snail infections was observed to be the highest in May (5.06% and August (5.61% and the lowest in March (0.74% and February (0.68%. However there was no infection observed through November to January. Seasonal prevalence of the developmental stages of F. gigantica infection in Lymnaea snails was also studied. Highest prevalence (4.63% was recorded during rainy season and lowest prevalence (0.76% was recorded during winter season. The study revealed that the developmental stages of F. gigantica infection in snail populations decreases from November to January and increases from February to October and highest in August and September in Sylhet region of Bangladesh.

Within- and among-family variation in parasite load and parasite-induced mortality in the land snail Arianta arbustorum, a host of parasitic mites.

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Schüpbach, Hans Ulrich; Baur, Bruno

2010-08-01

Variation in host susceptibility and parasite-induced mortality are preconditions for parasite-related selection on host populations. In terrestrial gastropods, variation in resistance against ectoparasite infection is poorly understood. We examined the within- and among-family variation in parasite load in full-siblings of the land snail Arianta arbustorum experimentally infected with Riccardoella limacum , a mite living in the mantle cavity of helicid land snails. We also quantified the influence of family origin and host size on parasite load and calculated its heritability (h(2)). Furthermore, we examined the influence of parasite load, snail size, and family origin on host winter mortality, an important life-history trait of A. arbustorum . Parasite load was heritable (h(2) = 0.63). In infected snails, parasite load was affected by family origin and increased with increasing shell size. Host mortality during hibernation increased with increasing parasite load and differed among families, but was not affected by snail size. Our results show high among-family variation both in resistance against ectoparasite infection and in host winter mortality. Furthermore, we show that parasite load is linked to snail size, which suggests that the proliferation of R. limacum is limited by resources provided by A. arbustorum .

The Three Gorges Dam: Does the Flooding Time Determine the Distribution of Schistosome-Transmitting Snails in the Middle and Lower Reaches of the Yangtze River, China?

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Yu Yang

2018-06-01

Full Text Available Background: Schistosomiasis is one of the most devastating tropical diseases in the world. Oncomelania hupensis is the only intermediate host of Schistosoma japonicum, and its growth and development are sensitive to environmental factors. The Three Gorges Dam has substantially altered the water level in the Yangtze River. This study focused on the impact of the flooding time on the occurrence of Oncomelania snails in Hunan Province, China. Methods: The data regarding Oncomelania snails were collected from the Schistosomiasis Atlas of the People’s Republic of China. Air temperature, hours of daylight and relative humidity from 1995 to 2002 were collected from the China Meteorological Data Sharing Service System. The data for rainfall and days inundated with water were collected from the Hunan flood control information system and hydrological stations in Hunan Province. A generalized additive model was used to estimate the impact of these factors on the presence or absence of snails. Results: The number of days inundated with water in the areas with snails ranged from 56 to 212 days. However, 82 percent of the areas without snails were inundated with water less than 60 days. The lowest air temperature in a year in the areas without snails ranges from −2.88 °C to −2.10 °C, and the range was from −2.88 °C to −2.34 °C for areas with snails. Annual rainfall in the areas with snails ranged from 989 to 1565 mm, and the range was from 1230 mm to 1647 mm for the areas without snails. The results from the generalized additive model showed that the number of days inundated with water, lowest air temperature in a year, annual rainfall, days of daily rainfall greater than 0.1 mm, and hours of daylight were the factors that significantly affect the occurrence of snails in Hunan Province, China. Conclusions: The number of days inundated with water may be a key factor determining the geographical distribution of Oncomelania snails in Hunan Province

Growth, Age Determination and Longevity in the Giant African Snail ...

African Journals Online (AJOL)

Growth rates in terms of shell lengths were investigated in four subspecies of Archachatina marginata (Swainson) under culture conditions. Number of shell whorls, shell pigmentation and microsculpture were also studied to assess their usefulness in age determination. The snails displayed a sigmoid growth pattern, with ...

The influence of diet on the δ 13C of shell carbon in the pulmonate snail Helix aspersa

Science.gov (United States)

Stott, Lowell D.

2002-02-01

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

MYCOTOXINS CONTAMINATION IN EDIBLE LAND SNAIL AT GRAZING PADDOCK ENVIRONMENT

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Ime Ebenso

2013-02-01

Full Text Available Mycotoxins contamination of animal products is under reported. Juvenile edible land snails (Archachatina marginata were exposed as sentinels in bottomless metal drums for 1 week at abandoned, new and reference sites respectively at grazing paddock environment, to assess the presence of foodborne microbiological mycotoxins contamination during the dry season. Mycological analysis of A. marginata samples revealed high (p<0.05 contamination at all paddocks ranged from 1.2-1.3 x 105 cfu-g. Results revealed values that were found to be unacceptable by FAO/WHO standards. The presence of Aspergillus niger, A. fumigatus and Penicillum expansum were noted as potential toxicogenic mycoflora. Snails were tolerant to all levels of contamination with no clinical signs of infection or mortality. This finding could serve as basis for assessing pre-slaughter microbial contamination of livestock farm/field environment in order to establish data with comparative epidemiological value, which could highlight early warning signals of food safety risk and cross-contamination of mycotoxins in the food chain.

Arsenic Trioxide Modulates the Central Snail Neuron Action Potential

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Guan-Ling Lu

2009-09-01

Conclusion: As2O3 at 10 mM elicits BoPs in central snail neurons and this effect may relate to the PLC activity of the neuron, rather than protein kinase A activity, or calcium influxes of the neuron. As2O3 at higher concentration irreversibly abolishes the spontaneous action potentials of the neuron.

Trace metallic elements in Helix aspersa terrestrial snails of a semiarid ecosystem; Elementos metalicos traza en caracoles terrestres Helix aspersa de un ecosistema semiarido

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Gaso P, M.I.; Segovia, N.; Zarazua, G.; Montes, F. [Instituto Nacional de Investigaciones Nucleares, A.P. 18-1027, 11801 Mexico D.F. (Mexico); Morton, O.; Armienta, M.A.; Hernandez, E. [IGF-UNAM, Ciudad Universitaria, 04510 Mexico D.F. (Mexico)

2001-07-01

The concentration of some major elements and traces in soil samples and of Helix aspersa eatable terrestrial snails were analysed at the Radioactive Wastes Storage Center (CADER) and in other reference sites. The methodology includes the use of an atomic absorption spectrophotometer, an X-ray fluorescence equipment and an Icp-mass spectroscope. The concentrations of some toxic elements (Ba, Cd, Cr, Ni, Pb and V) in the soft tissue of the snails were greater than the toxic levels reported in the literature for such trace elements. The snails compared with another wild eatable foods present transfer coefficients soil-snail high relatively. (Author)

Adaptive Changes in the Vestibular System of Land Snail to a 30-Day Spaceflight and Readaptation on Return to Earth

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Nikolay Aseyev

2017-11-01

Full Text Available The vestibular system receives a permanent influence from gravity and reflexively controls equilibrium. If we assume gravity has remained constant during the species' evolution, will its sensory system adapt to abrupt loss of that force? We address this question in the land snail Helix lucorum exposed to 30 days of near weightlessness aboard the Bion-M1 satellite, and studied geotactic behavior of postflight snails, differential gene expressions in statocyst transcriptome, and electrophysiological responses of mechanoreceptors to applied tilts. Each approach revealed plastic changes in the snail's vestibular system assumed in response to spaceflight. Absence of light during the mission also affected statocyst physiology, as revealed by comparison to dark-conditioned control groups. Readaptation to normal tilt responses occurred at ~20 h following return to Earth. Despite the permanence of gravity, the snail responded in a compensatory manner to its loss and readapted once gravity was restored.

Effect of Twist, Snail and YB-1 gene expression in cervical cancer tissue on cell invasion and epithelial-mesenchymal transition

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Xin-Qin Kang1

2017-05-01

Full Text Available Objective: To study the effect of Twist, Snail and YB-1 gene expression in cervical cancer tissue on cell invasion and epithelial-mesenchymal transition. Methods: Cervical cancer tissue samples and tissue samples adjacent to carcinoma were collected from 138 patients with radical operation for cervical cancer, fluorescence quantitative PCR method was used to detect the mRNA expression of Twist, Snail and YB-1 genes, cell invasion-related genes and epithelial-mesenchymal transition marker genes, the Pearson test was used to analyze the correlation of Twist, Snail and YB-1 gene mRNA expression in cervical cancer tissue with cell invasion and epithelial-mesenchymal transition. Results: Twist, Snail and YB-1 gene mRNA expression in cervical cancer tissue were higher than those in tissue adjacent to carcinoma, the invasion genes STAT3, YAP1, TUG1, FoxM1 and Rab11 mRNA expression were higher than those in tissue adjacent to carcinoma, and the epithelial-mesenchymal transition markers E-cadherin and β-catenin gene mRNA expression were lower than those in tissue adjacent to carcinoma while vimentin gene mRNA expression was higher than that in tissue adjacent to carcinoma. Pearson test showed that Twist, Snail and YB-1 gene mRNA expression in cervical cancer tissue were directly correlated with cell invasion and epithelial-mesenchymal transition. Conclusion: Twist, Snail and YB-1 genes are highly expressed in cervical cancer tissue, and their abnormal expression directly leads to the increased tumor cell invasion activity and the aggravated epithelial-mesenchymal transition.

A Targeted Capture Linkage Map Anchors the Genome of the Schistosomiasis Vector Snail, Biomphalaria glabrata.

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Tennessen, Jacob A; Bollmann, Stephanie R; Blouin, Michael S

2017-07-05

The aquatic planorbid snail Biomphalaria glabrata is one of the most intensively-studied mollusks due to its role in the transmission of schistosomiasis. Its 916 Mb genome has recently been sequenced and annotated, but it remains poorly assembled. Here, we used targeted capture markers to map over 10,000 B. glabrata scaffolds in a linkage cross of 94 F1 offspring, generating 24 linkage groups (LGs). We added additional scaffolds to these LGs based on linkage disequilibrium (LD) analysis of targeted capture and whole-genome sequences of 96 unrelated snails. Our final linkage map consists of 18,613 scaffolds comprising 515 Mb, representing 56% of the genome and 75% of genic and nonrepetitive regions. There are 18 large (> 10 Mb) LGs, likely representing the expected 18 haploid chromosomes, and > 50% of the genome has been assigned to LGs of at least 17 Mb. Comparisons with other gastropod genomes reveal patterns of synteny and chromosomal rearrangements. Linkage relationships of key immune-relevant genes may help clarify snail-schistosome interactions. By focusing on linkage among genic and nonrepetitive regions, we have generated a useful resource for associating snail phenotypes with causal genes, even in the absence of a complete genome assembly. A similar approach could potentially improve numerous poorly-assembled genomes in other taxa. This map will facilitate future work on this host of a serious human parasite. Copyright © 2017 Tennessen et al.

Use of chemical methods to assess Cd and Pb bioavailability to the snail Cantareus aspersus: A first attempt taking into account soil characteristics

International Nuclear Information System (INIS)

Pauget, B.; Gimbert, F.; Coeurdassier, M.; Scheifler, R.; Vaufleury, A. de

2011-01-01

Highlights: → New methodology to identify chemical method able to assess metal bioavailability to snails. → Bioavailability of cadmium and lead to snails was determined by assessing accumulation kinetics. → Toxicokinetics were used to as a measure of bioavailability and related with chemical measures of metal availability. → Bioavailability of cadmium and lead was affected by different pH and organic matter content but not by clay content. → Concentrations of CaCl 2 extract and total dissolved metal estimate were not able to predict bioavailability to the snails. - Abstract: Bioavailability is a key parameter in conditioning contaminant transfer to biota. However, in risk assessment of terrestrial contamination, insufficient attention is being paid to the influence of soil type on trace metal bioavailability. This paper addresses the influence of soil properties on the chemical availability of cadmium (Cd) and lead (Pb) (CaCl 2 extraction and ionic activity) and bioavailability (accumulation kinetics) to the land snail Cantareus aspersus. Snails were exposed to nine contaminated soils differing by a single characteristic (pH or organic matter content or clay content) for 28 days. Toxicokinetic models were applied to determine metal uptake and excretion rates in snails and multivariate regression was used to relate uptake parameters to soil properties. The results showed that alkalinisation of soil and an increase of the organic matter content decreased Pb and Cd bioavailability to snails whereas kaolin clay had no significant influence. The CaCl 2 -extractable concentrations tended to overestimate the effects of pH when used to explain metal uptake rate. We conclude that factors other than those controlling the extractable fraction affect metal bioavailability to snails, confirming the requirement of biota measurements in risk assessment procedures.