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1

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

Microsoft Academic Search

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

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

2

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

PubMed Central

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. PMID:23878796

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

2013-01-01

3

New scope on the relationship between rotifers and Biomphalaria alexandrina snails  

PubMed Central

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

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

2013-01-01

4

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

PubMed

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

Omran, Nahla Elsayed; Salama, Wesam Mohamed

2013-11-01

5

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

PubMed

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

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

2015-01-01

6

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

PubMed Central

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

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

2014-01-01

7

Biomphalaria alexandrina in Egypt: past, present and future.  

PubMed

The African species of Biomphalaria appeared as a result of the relatively recent west-to-east trans-Atlantic dispersal of the Biomphalaria glabrata-like taxon. In Egypt, Biomphalaria alexandrina is the intermediate host for Schistosoma mansoni. Biomphalaria alexandrina originated in the area between Alexandria and Rosetta and has historically been confined to the Nile Delta. Schistosoma mansoni reached Egypt via infected slaves and baboons from the Land of Punt through migrations that occurred as early as the Vth Dynasty. The suggestion of the presence of Schistosoma mansoni infection in Lower Egypt during Pharaonic times is discussed despite the fact that that there is no evidence of such infection in Egyptian mummies. It is only recently that Biomphalaria alexandrina colonized the Egyptian Nile from the Delta to Lake Nasser. This change was likely due to the construction of huge water projects, the development of new water resources essential for land reclamation projects and the movement of refugees from the Suez Canal zone to the Delta and vice versa. The situation with respect to Biomphalaria in Egypt has become complicated in recent years by the detection of Biomphalaria glabrata and a hybrid between both species; however, follow-up studies have demonstrated the disappearance of such species within Egypt. The National Schistosoma Control Program has made great strides with respect to the eradication of schistosoma; however, there has unfortunately been a reemergence of Schistosoma mansoni resistant to praziquantel. There are numerous factors that may influence the prevalence of snails in Egypt, including the construction of water projects, the increase in reclaimed areas, global climate change and pollution. Thus, continued field studies in addition to the cooperation of several scientists are needed to obtain an accurate representation of the status of this species. In addition, the determination of the genome sequence for Biomphalaria alexandrina and the use of modern technology will allow for the study of the host-parasite relationship at a molecular level. PMID:23938396

Abou-El-Naga, Iman F

2013-09-01

8

Differences in susceptibility of Biomphalaria alexandrina to Schistosoma mansoni from Gize and Dakahlia Governorates, Egypt.  

PubMed

Biomphalaria alexandrina snails were collected from irrigation canals at Gize and Dakahlia Governorates. They were exposed to strains of Schistosoma mansoni from these localities. The snails showed different rates of susceptibility to the parasite. There was a high range of snail sensitivity to S. mansoni infection (53.9%-60.7%) when snail populations and parasite strains were from the same governorate. Supporting this was the high cercarial production from infected snails of these cases (288.2 cercariae/ snail/week of Dakahlia-Dakahlia group). However, snail populations and parasite strains from different Governorates (Gize-Dakahlia) exhibited poor values of snail sensitivity and cercarial production with significant variations from those of the group of the same governorate. PMID:8754642

Haroun, N H

1996-08-01

9

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

NASA Astrophysics Data System (ADS)

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

Sanad Soliman, Mahmoud; El-Ansary, Afaf

10

In vivo, attenuation of schistosome cercarial development and disturbance of egg laying capacity in Biomphalaria alexandrina using sublethal concentrations of plant molluscicides.  

PubMed

The dry powdered of Sinapis arvensis, Thymelaea hirsuta, Callistemon lanceolatus and Peganum harmala showed molluscicidal activity against Biomphalaria alexandrina, specific intermediate hosts to Schistosoma mansoni. Effect of LC25 of dry powdered plant molluscicides on hexokinase (HK), glucose phosphate isomerase (GPI), AMP deaminase, adenosine deaminase and phenol oxidase (PO) of B. alexandrina was traced. C. lanceolatus showed the highest molluscicidal activity as it has the lowest LC50 compared to S. arvensis, T. hirsuta, and P. harmala. LC25 of the latter three plants resulted in more significant inhibition of HK, GPI, AMP-deaminase and PO than C. lanceolatus. Treatment of snails with LC10 of these plants markedly affected compatibility of B. alexandrina to S. mansoni infection. Significant decrease in cercarial production recorded in snails treated with sublethal concentrations of S. arvensis, T. hirsuta, and P. harmala. Remarkable impairment of the egg laying capacity of molluscicide-treated snails was also recorded. Correlation between activity levels of HK, GPI and AMP deaminase and compatibility to parasitic infection and role of PO in the egglaying capacity of these snail species were discussed. PMID:11775093

el-Ansary, A; Sammour, E M; Soliman, M S; Gawish, F A

2001-12-01

11

Biomphalaria glabrata: a new threat for schistosomiasis transmission in Egypt.  

PubMed

This is the first report on the infestation of irrigation and drainage systems at Giza, Qalyoubiya and Kafr El Shiekh Governorates, with Biomphalaria glabrata (the snail host of Schistosoma mansoni in the new world). Identification of this snail species was based on morphometry of the shell, shape of the radular lateral teeth and presence of the characteristic renal ridge. B. glabrata snails collected from natural water courses in Egypt proved to be susceptible to a local strain of S. mansoni. These snails were infected by 52% versus 75% for Biomphalaria alexandrina (the only local host) under the same laboratory conditions. Meanwhile the periodic total cercarial production was higher in B. glabrata than in B. alexandrina (252 +/- 110 cercariae/snail versus 203 +/- 86 cercariae/snail, respectively). Differences in infection rate, length of schistosome incubation period, duration of cercarial shedding and cercarial production in various sizes of the two snail species are reported and discussed. PMID:8721240

Yousif, F; Haroun, N; Ibrahim, A; El-Bardicy, S

1996-04-01

12

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

Microsoft Academic Search

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

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

2000-01-01

13

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

PubMed

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

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

2000-05-01

14

Fasciola immature stages sought in Lymnaea species and Biomphalaria species in the water bodies of Dakahlia Governorate.  

PubMed

Examination of the five different water bodies in Dakahlia governorate, revealed four species of Lymnaea. These were L. natalensis (68.4%). L. truncatula (16%), L. stagnalis (12.2%) and L. columella (3.4%). Also, two species of Biomphalaria were recovered. These were B. alexandrina (54.7%) and B. glabrata (45.3%). Examination of all these snails showed natural infection with immature stages of Fasciola sp. in 5.5% of L. natalensis (= cailliaudi), 3.1% in L. truncatula and 0.67% in B. alexandrina. The importance of these snails in dissemination and spreading of fascioliasis was discussed. PMID:12049247

el-Shazly, Atef M; Helmy, Moshira M F; Haridy, Fouad M; el-Sharkawy, Eman M A; Morsy, Tosson A

2002-04-01

15

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

PubMed

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

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

2013-11-01

16

Specific identification of Egyptian Biomphalaria species and possible hybrids using the polymerase chain reaction based on nuclear and mitochondrial loci.  

PubMed

The snail historically implicated in the transmission of Schistosoma mansoni in Egypt is Biomphalaria alexandrina. The problem of schistosomiasis in Egypt has been complicated in recent years by the introduction of Biomphalaria glabrata, which has been reported to hybridize with B. alexandrina. Both introduced and hybrid snails also pose a threat with respect to S. mansoni transmission. As morphological differentiation of these snails is difficult, using three DNA loci, nuclear ITS1 and ITS2, and mitochondrial ND1, PCR-based assays were developed to identify these species and possible hybrids. The assays are rapid, reproducible, sensitive and specific. This technique may be used in field surveys to study the distribution of the two species of intermediate host and their putative hybrids in Egypt. PMID:15652216

Lotfy, Wael M; DeJong, Randall J; Black, Brandee S; Loker, Eric S

2005-02-01

17

Incidence of Parastrongylus cantonensis larvae in different fresh water snails in Dakahlia Governorate.  

PubMed

Samples of snails were collected from different water bodies in Dakahlia governorate to assess a survey on the naturally infected snails and their infection rate with the Parastrongylus cantonensis larvae. The nematode P. cantonensis is associated in the etiology of eosinophilic meningeoencephalitis of man. Lanistes carinatus showed the highest rate of infection with 19-400 larvae per snail. Biomphalaria alexandrina, B. glabrata, Bulinus truncatus, Lymnaea cailliaudi (natalensis), L. alexandrina, and Cleopatra cyclostomoides were found naturally infected with the larvae of P. cantonensis for the first time in Egypt. The number of larvae per infected snail varied depending on the snail type. The highest rate (39.2%) of infected snails was collected from the end canals at Tanneekh and the lowest in the river Nile (12.5%). PMID:12214935

el-Shazly, A M; el-Hamshary, Eman M; el-Shewy, Khalid M; Rifaat, Manal M A; el-Sharkawy, Iman M A

2002-08-01

18

Nucleolar organizer regions in Biomphalaria and Bulinus snails  

Microsoft Academic Search

Summary A method is described for the demonstration of nucleolar organizer regions (NORs) in freshwater snails and is applied to the study of one tetraploid and several diploid populations ofBulinus. We present evidence of dosage compensation with respect to the expression of NORs in that diploids and tetraploids both exhibit only 1 pair of NOR-bearing chromosomes.

M. A. Goldman; P. T. LoVerde; C. L. Chrisman; D. A. Franklin; F. Matthews; R. J. Pitchford; C. S. Richards

1983-01-01

19

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

NASA Technical Reports Server (NTRS)

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

Gao, Wenyuan; Wiederhold, Michael; Hejl, Robert

1997-01-01

20

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

PubMed Central

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

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

2014-01-01

21

Biomphalaria glabrata transcriptome: cDNA microarray profiling identifies resistant and susceptible-specific gene expression in haemocytes from snail strains exposed to Schistosoma mansoni  

Microsoft Academic Search

BACKGROUND: Biomphalaria glabrata is an intermediate snail host for Schistosoma mansoni, one of the important schistosomes infecting man. B. glabrata\\/S. mansoni provides a useful model system for investigating the intimate interactions between host and parasite. Examining differential gene expression between S. mansoni-exposed schistosome-resistant and susceptible snail lines will identify genes and pathways that may be involved in snail defences. RESULTS:

Anne E Lockyer; Jenny Spinks; Richard A Kane; Karl F Hoffmann; Jennifer M Fitzpatrick; David Rollinson; Leslie R Noble; Catherine S Jones

2008-01-01

22

Genetic diversity, fixation and differentiation of the freshwater snail Biomphalaria pfeifferi (Gastropoda, Planorbidae) in arid lands.  

PubMed

The freshwater snail Biomphalaria pfeifferi is the main intermediate host of human intestinal Bilharziasis. It is widely distributed in Africa, Madagascar and middle-eastern countries, and its habitat includes wetlands, and arid to semi-arid areas. Based on analysis of 18 microsatellites, we investigated reference allelic variation among 30 populations of B. pfeifferi from three drainage basins in Dhofar, Oman (the eastern limit of its distribution). This is an arid to semi-arid region, with a 9,000-year history of very low rainfall, but is subject to unpredictable and destructive flash floods. In this context we showed that genetic fixation was very high compared to genetic differentiation which was moderate and, that, relative to B. pfeifferi populations from wetlands, the populations in Dhofar show evidence of lower levels of genetic diversity, a higher degree of genetic fixation, a quasi-absence of migration, and a higher level of genetic drift. Despite the extreme conditions in the Dhofar habitat of this species, it is able to survive because of its very high self-fertilization (approaching 100 %) and fecundity rates. PMID:23543205

Mintsa Nguema, Rodrigue; Langand, Juliette; Galinier, Richard; Idris, Mohamed A; Shaban, Mahmoud A; Al Yafae, Salem; Moné, Hélène; Mouahid, Gabriel

2013-06-01

23

Differences in the number of hemocytes in the snail host Biomphalaria tenagophila, resistant and susceptible to Schistosoma mansoni infection.  

PubMed

The relationships between schistosomiasis and its intermediate host, mollusks of the genus Biomphalaria, have been a concern for decades. It is known that the vector mollusk shows different susceptibility against parasite infection, whose occurrence depends on the interaction between the forms of trematode larvae and the host defense cells. These cells are called amebocytes or hemocytes and are responsible for the recognition of foreign bodies and for phagocytosis and cytotoxic reactions. The defense cells mediate the modulation of the resistant and susceptible phenotypes of the mollusk. Two main types of hemocytes are found in the Biomphalaria hemolymph: the granulocytes and the hyalinocytes. We studied the variation in the number (kinetics) of hemocytes for 24 h after exposing the parasite to genetically selected and non-selected strains of Biomphalaria tenagophila, susceptible or not to infection by Schistosoma mansoni. The differences were analyzed referred to the variations in the number of hemocytes in mollusks susceptible or not to infection by S. mansoni. The hemolymph of the selected and non-selected snails was collected, and hemocytes were counted using a Neubauer chamber at six designated periods: 0 h (control, non-exposed individuals), 2 h, 6 h, 12 h, 18 h and, 24 h after parasite exposure. Samples of hemolymph of five selected mollusks and five non-selected mollusks were separately used at each counting time. There was a significant variation in the number of hemocytes between the strains, which indicates that defense cells have different behaviors in resistant and susceptible mollusks. PMID:21174263

Oliveira, A L D; Levada, P M; Zanotti-Magalhaes, E M; Magalhães, L A; Ribeiro-Paes, J T

2010-01-01

24

Life-history traits indicate local adaptation of the schistosome parasite, Schistosoma mansoni, to its snail host, Biomphalaria pfeifferi.  

PubMed

The digenean trematode Schistosoma mansoni causes schistosomiasis (Bilharziasis), a significant human disease especially in sub-Saharan Africa. We tested local adaptation of this parasite to its intermediate host, the freshwater snail Biomphalaria pfeifferi, by exposure of S. mansoni to B. pfeifferi from one sympatric and four allopatric populations and measurement of life-history traits of both species over time. The pre-patent period, infection rate, and cercarial production of the parasite were determined, and the shell diameter, fecundity, and survival of the snail host were determined. The results provide evidence for local adaptation of S. mansoni to its sympatric snail host: the pre-patent period was the shortest, the cercarial production was moderate and accompanied by a higher survival rate, the growth was greater during the pre-patent period, and the fecundity was greater during the pre-patent period. The greater growth and fecundity of sympatric B. pfeifferi suggests the presence of growth and fecundity compensation. These fitness traits are relevant to energy allocation of the snail host and to the transmission strategy of the schistosome parasite. PMID:23031799

Ibikounlé, M; Mouahid, G; Mintsa Nguéma, R; Sakiti, N G; Kindé-Gasard, D; Massougbodji, A; Moné, H

2012-12-01

25

Successful parasitism of vector snail Biomphalaria glabrata by the human blood fluke (trematode) Schistosoma mansoni: a 2009 assessment  

PubMed Central

Schistosomiasis, caused by infections by human blood flukes (Trematoda), continues to disrupt the lives of over 200,000,000 people in over 70 countries, inflicting misery and precluding the individuals’ otherwise reasonable expectations of productive lives. Infection requires contact with freshwater in which infected snails (the intermediate hosts of schistosomes) have released cercariae larvae. Habitats suitable for the host snails continue to expand as a consequence of water resource development. No vaccine is available, and the emergence and spread of resistance to the single licensed schistosomicide drug would be devastating. Since human infections would cease if parasite infections in snails were prevented, efforts are being made to discover requirements of intra-molluscan development of these parasites. Wherever blood flukes occur, naturally resistant conspecific snails are present. To understand the mechanisms used by parasites to ensure their survival in immunocompetent hosts, one must comprehend the internal defense mechanisms that are available to the host. For one intermediate host snail (Biomphalaria glabrata) and trematodes for which it serves as vector, molecular genetic and proteomic surveys for genes and proteins influencing the outcomes on infections are yielding lists of candidates. A comparative approach drawing on data from studies in divergent species provides a robust basis for hypothesis generation to drive decisions as to which candidates merit detailed further investigation. For example, reactive oxygen and nitrogen species are known mediators or effectors in battles between infectious agents and their hosts. An approach targeting genes involved in relevant pathways has been fruitful in the Schistosoma mansoni-B. glabrata parasitism, leading to discovery of a functionally relevant gene set (encoding enzymes responsible for the leukocyte respiratory burst) that associates significantly with host resistance phenotype. This review summarizes advances in the understanding of strategies used by both this trematode parasite and its molluscan host to ensure their survival. PMID:19393158

Bayne, Christopher J.

2009-01-01

26

Schistosoma mansoni in susceptible and resistant snail strains Biomphalaria tenagophila: in vivo tissue response and in vitro hemocyte interactions.  

PubMed

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

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

2012-01-01

27

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

PubMed Central

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

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

2012-01-01

28

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

PubMed

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

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

2014-11-01

29

Bibliotheca Alexandrina  

NSDL National Science Digital Library

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

30

A potential snail host of schistosomiasis in Bolivia: Biomphalaria amazonica Paraense, 1966.  

PubMed

Biomphalaria amazonica Paraense, 1996 was collected from a permanent pond in the outskirts of the Bolivian city of Santa Cruz. Identification of the collected specimens was made by comparison with the original description of the species and with topotypic material in the collection of Instituto Oswaldo Cruz. Phylogenetic analysis confirmed that these Bolivian specimens belong to B. amazonica. PMID:12386698

Pointier, J P; Paraense, W L; Dejong, R J; Loker, E S; Bargues, M D; Mas-Coma, S

2002-09-01

31

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

PubMed

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

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

2014-12-01

32

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

PubMed Central

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

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

2013-01-01

33

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

Microsoft Academic Search

Peptidoglycan (PGN) recognition proteins (PGRPs) and gram-negative bacteria binding proteins (GNBPs) play an essential role\\u000a in Toll\\/Imd signaling pathways in arthropods. The existence of homologous pathways involving PGRPs and GNBPs in other major\\u000a invertebrate phyla such as the Mollusca remains unclear. In this paper, we report four full-length PGRP cDNAs and one full-length GNBP cDNA cloned from the snail Biomphalaria

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

2007-01-01

34

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

PubMed

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

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

2014-04-01

35

Activation of an innate immune response in the schistosome-transmitting snail Biomphalaria glabrata by specific bacterial PAMPs  

PubMed Central

Injection of crude lipopolysaccharide (LPS) from Eschericia coli into the hemocoel of Biomphalaria glabrata stimulates cell proliferation in the amebocyte-producing organ (APO). However, it is not known if mitogenic activity resides in the lipid A or O-polysaccharide component of LPS. Moreover, the possible role of substances that commonly contaminate crude LPS and that are known to stimulate innate immune responses in mammals, e.g., peptidoglycan (PGN), protein, or bacterial DNA, is unclear. Therefore, we tested the effects of the following injected substances on the snail APO: crude LPS, ultrapurified LPS (lacking lipoprotein contamination), two forms of lipid A, (diphosphoryl lipid A and Kdo2-lipid A), O-polysaccharide, Gram negative PGN, both crude and ultrapurified (with and without endotoxin activity, respectively), Gram positive PGN, PGN components Tri-DAP and muramyl dipeptide, and bacterial DNA. Whereas crude LPS, ultrapurified LPS, and crude PGN were mitogenic, ultrapurified PGN was not. Moreover, LPS components, PGN components, and bacterial DNA were inactive. These results suggest that it is the intact LPS molecule which stimulates cell division in the APO. PMID:24113288

Sullivan, John T.; Belloir, Joseph A.

2013-01-01

36

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

PubMed Central

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

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

2012-01-01

37

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

PubMed

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

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

2006-09-01

38

[Life cycle of Clinostomum golvani n. sp. (Trematoda : Clinostomidae) a larval parasite of Biomphalaria glabrata, the snail vector of Schistosoma mansoni in Guadeloupe (author's transl)].  

PubMed

The life cycle of a new species of Clinostomidae, Clinostomum golvani, described in Guadeloupe (French West Indies). The first intermediate host is the snail vector of Schistosoma mansoni in this island, Biomphalaria glabrata, which can be sterilized by this parasite. Poecilia reticulata (guppy) serves as the second intermediate host. Adult worms were obtained under experimental conditions from Butorides virescens (the definitive host in nature), Nycticorax nycticorax and Ardea purpurea. The adult worm closely resembles Clinostomum complanatum but the larval stages (rediae and cercaria) show several differences. The chaetotaxic description of a cercaria of Clinostomidae is given for the first time. PMID:7224533

Nassi, H; Bayssade-Dufour, C

1980-01-01

39

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

PubMed

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. PMID:25055099

Oliveira-Filho, E C; Caixeta, N R; Simplício, N C S; Sousa, S R; Aragão, T P; Muniz, D H F

2014-02-01

40

Laboratory Studies on the Prevalence and Cercarial Rhythms of Trematodes from Bulinus truncatus and Biomphalaria Pfeifferi Snails from Khartoum State, Sudan  

PubMed Central

ObjectiveS: (a) To determine the natural infection rate of Bulinus truncatus and Biomphalaria pfeifferi snails with trematodes’ cercariae. (b) To determine the emergence and rhythmicity of cercariae. (c) To elucidate the high-risk time for man and other animals to acquire infection. Methods: Snails were collected from Dawar El Mahadi Agricultural Scheme, Khartoum State, identified in the laboratory, kept at room temperature and fed on lettuce. The snails were screened weekly for six weeks for natural infection and infected snails were kept in the dark. The swimming patterns and resting position of the freshly emerged cercariae were studied using a stereomicroscope. The rhythmicity of the different types of cercariae was studied by screening three sets of 5 naturally infected snails under fluorescent light from 07.00 to 19.00 and similar sets from 19.00 to 07.00. Results: Out of 1,257 screened Bulinus truncatus, 187 (14.9%) shed four types of cercariae. The highest prevalence of natural infection (9.5%) was by schistosome cercariae followed by amphistome (2.5%), xiphidiocercariae (2.4%) and lastly by avian cercariae (0.5%). However, out of 200 screened B. pfeifferi, 22 (11%) shed only xiphidiocercariae. The rhythmicity studies showed that the emergence of schistosome cercariae increased steadily from 07.00 to reach its peak at 11.00–13.00. The emergence rhythms of avian cercariae are similar to those of the schistosome, but with an early peak at 09.00–11.00. The xiphidiocercariae and amphistome cercariae started with high rate of emergence at 07.00. and decreased gradually to very low levels or complete disappearance, respectively, around sunset. Conclusion: Information on cercarial rhythmicity and chronobiological characteristics are thought to be useful in avoiding water contact during high-risk time of infection and may be helpful in the identification of closely related species and strains of cercariae. PMID:21748137

Ahmed, Abdel Aziz M; Ibrahim, Nidal A; Idris, Mohamed A

2006-01-01

41

Elimination of Biomphalaria pfeifferi, Bulinus tropicus and Lymnaea natalensis by the ampullarid snail, Marisa cornuarietis, in a man-made dam in northern Tanzania.  

PubMed

Marisa cornuarietis is a well known ampullarid competitor/predator of Biomphalaria glabrata in Puerto Rico. For the first time in Africa a flourishing population of Marisa has been established in a small, permanent, man-made dam at Kisangara, near Moshi, Tanzania. Prior to the release of M. cornuarietis in June 1977, this dam supported thriving populations of the pulmonate snail hosts Biomphalaria pfeifferi and Lymnaea natalensis; Bulinus tropicus and the melaniid Melanoides tuberculata were also common. Some 24 months after the establishment of Marisa the three pulmonate species had been eliminated; only M. tuberculata remained at about the same population density as originally recorded. Marisa has not caused any obvious adverse environmental impact in the dam. There is at present no valid evidence that this ampullarid would be a threat to local rice production, which is the only crop at risk, but carefully designed field trials should be undertaken to confirm or refute this view. In view of the vast number of permanent, lentic habitats throughout the Afrotropical region, which act as important transmission sites of schistosomiasis and fascioliasis, the role of Marisa cornuarietis as a cost-effective biological control agent in integrated control operations deserves henceforth to be energetically explored. PMID:6122367

Nguma, J F; McCullough, F S; Masha, E

1982-03-01

42

Molecular epidemiology of Brazilian Biomphalaria: a review of the identification of species and the detection of infected snails.  

PubMed

The three vector species of Schistosoma mansoni in Brazil, Biomphalaria glabrata, B. tenagophila and B. straminea show different susceptibility levels to the trematode besides a wide geographical distribution. The identification of such molluscs is important to further understand the disease epidemiology. Considering the fact that morphological identification may become difficult or even impossible under particular circumstances, the use of molecular-based methods have permitted the generation of more consistent information concerning the population structure of Biomphalaria furthering knowledge on taxonomy and diagnosis of infection. We have developed methodologies in order to provide simultaneous species identification of the intermediate host and diagnosis of infection with S. mansoni. PMID:19426656

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

2009-07-01

43

Resistance of Biomphalaria glabrata 13-16-R1 snails to Schistosoma mansoni PR1 is a function of haemocyte abundance and constitutive levels of specific transcripts in haemocytes.  

PubMed

Continuing transmission of human intestinal schistosomiasis depends on the parasite's access to susceptible snail intermediate hosts (often Biomphalaria glabrata). Transmission fails when parasite larvae enter resistant individuals in wild snail populations. The genetic basis for differences in snail susceptibility/resistance is being intensively investigated as a means to devise novel control strategies based on resistance genes. Reactive oxygen species produced by the snail's defence cells (haemocytes) are effectors of resistance. We hypothesised that genes relevant to production and consumption of reactive oxygen species would be expressed differentially in the haemocytes of snail hosts with different susceptibility/resistance phenotypes. By restricting the genetic diversity of snails, we sought to facilitate identification of resistance genes. By inbreeding, we procured from a 13-16-R1 snail population with both susceptible and resistant individuals 52 lines of B. glabrata (expected homozygosity ~87.5%), and determined the phenotype of each in regard to susceptibility/resistance to Schistosoma mansoni. The inbred lines were found to have line-specific differences in numbers of spreading haemocytes; these were enumerated in both juvenile and adult snails. Lines with high cell numbers were invariably resistant to S. mansoni, whereas lines with lower cell numbers could be resistant or susceptible. Transcript levels in haemocytes were quantified for 18 potentially defence-related genes. Among snails with low cell numbers, the different susceptibility/resistance phenotypes correlated with differences in transcript levels for two redox-relevant genes: an inferred phagocyte oxidase component and a peroxiredoxin. Allograft inflammatory factor (potentially a regulator of leucocyte activation) was expressed at higher levels in resistant snails regardless of spread cell number. Having abundant spreading haemocytes is inferred to enable a snail to kill parasite sporocysts. In contrast, snails with fewer spreading haemocytes seem to achieve resistance only if specific genes are expressed constitutively at levels that are high for the species. PMID:24681237

Larson, Maureen K; Bender, Randal C; Bayne, Christopher J

2014-05-01

44

Identification and characterization of five transcription factors that are associated with evolutionarily conserved immune signaling pathways in the schistosome-transmitting snail Biomphalaria glabrata  

PubMed Central

Innate immunity consists of humoral and cellular components that play a vital role in regulation of defense responses to various pathogens in vertebrates and invertebrates. Recent studies have shown that Rel/DIF (dorsal-related immunity factor), Relish, STAT (signal transducer and activator of transcription (STAT), and CREB (cAMP response element-binding protein) transcription factors associated pathways are evolutionarily conserved across the animal kingdom. Although the primary role and general structure of the pathways in immunity have been revealed in many invertebrates, particularly arthropods, almost nothing is known about those pathways in the freshwater snail Biomphalaria glabrata, an intermediate host of the human blood fluke Schistosoma mansoni, a causative agent of human schistosomiasis. Given the central role of transcription factors (TF) in controlling expression of effector genes, understanding the role of a given TF is essential to obtaining insight into the general function of the corresponding signaling pathway. To better understand the immunity of B. glabrata, we investigated five homologues of TFs that have been shown to be associated with multiple prominent immune signaling pathways based on the considerable data reported from a wide phylogenetic range of animals. In this study we identified and characterized cDNAs of five TFs from B. glabrata, designated BgRelish, BgRel, BgSTAT1, BgSTAT2 and BgCREB, for the first time. Among the five TFs, Relish is first reported in Lophotrochozoa, one of three superphyla in Metazoa. Our identification of class I (BgRelish) and II (BgRel) NF-?B in B. glabrata suggests the two pathways, Toll-like receptor (TLR) and immune deficiency (IMD)-like pathways, are present in the superphylum Lophotrochozoa. Preliminarily expression studies indicate these TF-associated pathways may be involved in the snail's anti-schistosome response. This study not only advances our understanding of the snail defenses, but also provides new perspectives about the evolution of animal immunity. PMID:21696828

Zhang, Si-Ming; Coultas, Kristen A.

2011-01-01

45

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

PubMed Central

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

Zeng, Yong; Loker, Eric S.

2013-01-01

46

Field-derived Schistosoma mansoni and Biomphalaria pfeifferi in Kenya: a compatible association characterized by lack of strong local adaptation, and presence of some snails able to persistently produce cercariae for over a year.  

PubMed

Background Schistosoma mansoni is widely distributed in sub-Saharan Africa with Biomphalaria pfeifferi being its most widespread and important snail intermediate host. Few studies have examined the compatibility of field-derived B. pfeifferi snails with S. mansoni miracidia derived from human hosts. We investigated compatibility (as defined by shedding of cercariae following exposure to miracidia) of two isolates of S. mansoni from school children from Asao (western Kenya) and Mwea (central Kenya) with B. pfeifferi collected directly from Asao stream or the Mwea rice fields.MethodsWe exposed snails from both regions to four different doses of miracidia (1, 5, 10 and 25) from sympatric or allopatric S. mansoni, and maintained them in a shaded, screened out-of-doors rearing facility in Kisian, in western Kenya. Both snail survival and the number of snails that became infected were monitored weekly. This was done for 25 weeks post-exposure (PE). Those infected snails which survived beyond this period were monitored until they all died.ResultsAlthough overall survival of Mwea snails maintained in western Kenya was generally low, both sympatric and allopatric combinations of parasites and snails exhibited high compatibility (approximately 50% at a dose of one miracidium per snail), with an increase in infection rates as the miracidial dose was increased (P¿<¿0.002). Schistosomes were no more compatible with sympatric than allopatric snails, nor were snails less compatible with sympatric than allopatric schistosomes. Snail mortality increased significantly with dose of miracidia (P¿<¿0.05). Approximately 3% of Asao snails exposed to a low dose of sympatric miracidia (1 or 5) continued to shed cercariae for as long as 58 weeks post exposure.ConclusionsThere were no significant local adaptation effects for either schistosomes or snails. Also, the existence of ¿super-survivor¿ snails is noteworthy for its implications for current control initiatives that mostly rely on mass drug administration (MDA). Long-term shedders could provide an ongoing source of cercariae to initiate human infections for many months, suggesting care is required in considering how human MDA treatments are timed. Future control programs should incorporate means to eliminate infected snails to complement chemotherapy interventions in controlling schistosomiasis. PMID:25425455

Mutuku, Martin W; Dweni, Celestine K; Mwangi, Moses; Kinuthia, Joseph M; Mwangi, Ibrahim N; Maina, Geoffrey M; Agola, Lelo E; Zhang, Si-Ming; Maranga, Rosebella; Loker, Eric S; Mkoji, Gerald M

2014-11-26

47

Habitat characteristics for different freshwater snail species as determined biologically through macroinvertebrate information.  

PubMed

Macro-invertebrates including freshwater snails collected from 643 sites over 8 successive seasons among the River Nile, branches, main canals and certain drains in eight Egyptian Governorates. Thirteen snail species and one bivalve species were identified. The most distributed were Lanistus carinatus and Physa acuta while the most abundant were Cleopatra bulimoides and Physa acuta during the whole study. The sites that harbored each snail species in all the examined water-courses were grouped seasonally and their biological assessment was determined by their minimum and maximum total point similarity percentage to that of the corresponded reference site and mean of the total points. Habitats for most snail species attained minimum total point's similarity percentage less than 21% (very poor habitat) during autumn and winter then spring while during summer very poor habitat was harbored by only few snail species. P. acuta was the only survived snails in habitat which attained 0 as a minimum total point's similarity percentage during two seasons and L. carinatus and Succinea cleopatra during one season. With respect to medically important snails very poor sites constituted 23% of Biomphalaria alexandrina sites, 14% of Lymnaea natalensis and 9.4% of Bulinus truncatus sites. The studied macroinvertebrate matrices, total number of organisms, taxa richness, the Ephemeroptera, Plecoptera, and Trichoptera (EPT) index, ratio of EPT index to chironomidae, ratio of scraper to filtering collector, contribution of dominant macroinvertebrate major group, comparison revealed descending tolerances from B. alexanrina followed by L. natalensis then B. truncates, but Hilsenhoff Biotic Index (HBI) showed the same tolerance to organic pollution. PMID:22435158

El-Khayat, Hanaa M M; Mahmoud, Kadria M A; Mostafa, Bayomy B; Tantawy, Ahmad A; El-Deeb, Fatma A; Ragb, Fawzy M; Ismail, Nahed M; El-Said, Kalil M; Taleb, Hoda M Abu

2011-12-01

48

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

PubMed Central

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

2013-01-01

49

Biomphalaria havanensis Identified as a Potential Intermediate Host for the Digenetic Trematode Bolbophorus damnificus  

Microsoft Academic Search

The digenetic trematode Bolbophorus damnificus has been associated with mortalities in commercial channel catfish Ictalurus punctatus in the Mississippi Delta. In the life cycle of B. damnificus, the only confirmed first intermediate host is the ram's horn snail Planorbella trivolvis. Recently, the exotic snail Biomphalaria havanensis has been isolated in several channel catfish ponds in the Mississippi Delta. The aim

Marlena C. Yost; Linda M. Pote; David J. Wise; Brian S. Dorr; Terry D. Richardson

2009-01-01

50

Schistosoma mansoni : Effect on growth, fertility, and development of distal male organs in Biomphalaria glabrata exposed to miracidia at different ages  

Microsoft Academic Search

Growth, egg laying rate, and mortality ofBiomphalaria glabrata (Portorican strain), maintained in groups of two, after exposure at different ages (1, 2, 4, 6, 8 weeks) to three miracidia each ofSchistosoma mansoni (Liberian strain) were determined. The findings in infected snails were compared with those in exposed but uninfected (negative) and in unexposed snails. Younger snails were infected at higher

M. Meier; C. Meier-Brook

1981-01-01

51

Breeding of Biomphalaria tenagophila in mass scale.  

PubMed

An efficient method for breeding Biomphalaria tenagophila (Taim lineage/RS) was developed over a 5-year-period (2005-2010). Special facilities were provided which consisted of four cement tanks (9.4 x 0.6 x 0.22 m), with their bottom covered with a layer of sterilized red earth and calcium carbonate. Standard measures were adopted, as follows: each tank should contain an average of 3000 specimens, and would be provided with a daily ration of 35,000 mg complemented with lettuce. A green-house effect heating system was developed which constituted of movable dark canvas covers, which allowed the temperature to be controlled between 20 - 24 ºC. This system was essential, especially during the coldest months of the year. Approximately 27,000 specimens with a diameter of 12 mm or more were produced during a 14-month-period. The mortality rates of the newly-hatched and adult snails were 77% and 37%, respectively. The follow-up of the development system related to 310 specimens of B. tenagophila demonstrated that 70-day-old snails reached an average of 17.0 ± 0.9 mm diameter. The mortality rates and the development performance of B. tenagophila snails can be considered as highly satisfactory, when compared with other results in literature related to works carried out with different species of the genus Biomphalaria, under controlled laboratory conditions. PMID:23328724

Rosa, Florence Mara; Marques, Daisymara P Almeida; Maciel, Engels; Couto, Josiane Maria; Negrão-Corrêa, Deborah A; Teles, Horácio M Santana; Santos, João Batista dos; Coelho, Paulo Marcos Zech

2013-01-01

52

O-Glycosylation of snails.  

PubMed

The glycosylation abilities of snails deserve attention, because snail species serve as intermediate hosts in the developmental cycles of some human and cattle parasites. In analogy to many other host-pathogen relations, the glycosylation of snail proteins may likewise contribute to these host-parasite interactions. Here we present an overview on the O-glycan structures of 8 different snails (land and water snails, with or without shell): Arion lusitanicus, Achatina fulica, Biomphalaria glabrata, Cepaea hortensis, Clea helena, Helix pomatia, Limax maximus and Planorbarius corneus. The O-glycans were released from the purified snail proteins by ?-elimination. Further analysis was carried out by liquid chromatography coupled to electrospray ionization mass spectrometry and - for the main structures - by gas chromatography/mass spectrometry. Snail O-glycans are built from the four monosaccharide constituents: N-acetylgalactosamine, galactose, mannose and fucose. An additional modification is a methylation of the hexoses. The common trisaccharide core structure was determined in Arion lusitanicus to be N-acetylgalactosamine linked to the protein elongated by two 4-O-methylated galactose residues. Further elongations by methylated and unmethylated galactose and mannose residues and/or fucose are present. The typical snail O-glycan structures are different to those so far described. Similar to snail N-glycan structures they display methylated hexose residues. PMID:22581130

Stepan, Herwig; Pabst, Martin; Altmann, Friedrich; Geyer, Hildegard; Geyer, Rudolf; Staudacher, Erika

2012-05-01

53

The distribution of Biomphalaria spp. in different habitats in relation to physical, biological, water contact and cognitive factors in a rural area in Minas Gerais, Brazil.  

PubMed

A total of 256 sites in 11 habitats were surveyed for Biomphalaria in Melquiades rural area (State of Minas Gerais) in August and November 1999 and in March 2000. Of the 1,780 Biomphalaria collected, 1,721 (96.7%) were B. glabrata and 59 (3.3%) B. straminea. Snails were found in all habitats except in wells, with the largest mean numbers in tanks, seepage ponds and canals, and the smallest numbers in springs, rice fields and fishponds. People's knowledge of the occurrence of Biomphalaria at the collection sites and the presence of Biomphalaria ova were strongly correlated with the occurrence of snails, and distance between houses and collection sites, as well as water velocity were inversely correlated with Biomphalaria occurrence (p < 0.001). The strongest predictor o f Biomphalaria occurrence was the presence of tilapia fish in fishponds. Fourteen Biomphalaria (0.8% of all snails) found at 6 sites were infected with Schistosoma mansoni. Suggestions are made for the utilization of local people's knowledge in snail surveys and further studies are recommended on the possible use of tilapia for biological control of Biomphalaria in fishponds, as well as modeling of S. mansoni transmission and reinfection. PMID:11586427

Kloos, H; de Souza, C; Gazzinelli, A; Soares Filho, B S; da Costa Temba; Bethony, J; Page, K; Grzywacz, C; Lewis, F; Minchella, D; LoVerde, P; Oliveira, R C

2001-01-01

54

Snail Snooping.  

ERIC Educational Resources Information Center

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

Miller, Dorothy

1993-01-01

55

Demographic Responses to Multigeneration Cadmium Exposure in Two Strains of the Freshwater Gastropod, Biomphalaria  

E-print Network

Demographic Responses to Multigeneration Cadmium Exposure in Two Strains of the Freshwater cadmium exposure on two strains of the freshwater gastropod, Biomphalaria glabrata: the parasite- resistant BS90 and parasite-susceptible NMRI strains. Snails were exposed to waterborne cadmium for three

Miller, Tom

56

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

PubMed

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

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

2014-11-19

57

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

PubMed

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

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

2015-01-01

58

Land and water snails  

NSDL National Science Digital Library

Land snails live on the land and water snails make water their habitat. Land snails have shells to protect them and so do water snails. Land snails have two sets of antennae, while water snails only have one set.

Olivia Worland (Purdue University; Biological Sciences)

2008-06-03

59

Water snails  

NSDL National Science Digital Library

Water snails have a shell for protection. They have two tentacles, a foot, and a head and a tail region. Water snails have eyes at the base of their sensory stalks. The stalks are used to smell and feel around the snail's environment.

Scott Bauer (USDA; ARS)

2005-08-03

60

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

PubMed

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

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

1986-01-01

61

Genetic variability and molecular identification of Brazilian Biomphalaria species (Mollusca: Planorbidae).  

PubMed

Freshwater snails belonging to the genus Biomphalaria are intermediate hosts of the trematode Schistosoma mansoni in the Neotropical region and Africa. In Brazil, one subspecies and ten species of Biomphalaria have been identified: B. glabrata, B. tenagophila, B. straminea, B. occidentalis, B. peregrina, B. kuhniana, B. schrammi, B. amazonica, B. oligoza, B. intermedia and B.t. guaibensis. However, only the first three species are found naturally infected with S. mansoni. The classical identification of these planorbids is based on comparison of morphological characteristics of the shell and male and female reproductive organs, which is greatly complicated by the extensive intra-specific variation. Several molecular techniques have been used in studies on the identification, genetic structure as well as phylogenetic relationships between these groups of organisms. Using the randomly amplified polymorphic DNAs (RAPD) analysis we demonstrated that B. glabrata exhibits a remarkable degree of intra-specific polymorphism. Thus, the genetics of the snail host may be more important to the epidemiology of schistosomiasis than those of the parasite itself. Using the simple sequence repeat anchored polymerase chain reaction (SSR-PCR) in intra-populational and intra-specific studies we have demonstrated that snails belonging to the B. straminea complex (B. straminea, B. kuhniana and B. intermedia) clearly presented higher heterogeneity. Using the low stringency polymerase chain reaction (LS-PCR) technique we were able to separate B. glabrata from B. tenagophila and B. tenagophila from B. occidentalis. To separate all Brazilian Biomphalaria species we used the restriction fragment length polymorphism (PCR-RFLP) of the internal transcribed spacer region (ITS) of the DNA gene. The method also proved to be efficient for the specific identification of DNA extracted from snail eggs. Recently we have sequenced the ITS2 region for phylogenetic studies of all Biomphalaria snails from Brazil. PMID:11769284

Carvalho, S; Caldeira, R L; Simpson, A J; Vidigal, T H

2001-01-01

62

Effects of the organophosphate insecticide azinphos-methyl on the reproduction and cholinesterase activity of Biomphalaria glabrata  

Microsoft Academic Search

Azinphos-methyl is an organophosphate insecticide used for pest control on a number of food crops in many parts of the world. The snail Biomphalaria glabrata is a freshwater gastropod widely distributed in South America, Central America and Africa. The aim of the present work was to investigate whether azinphos-methyl causes alterations in the reproduction of B. glabrata. To this end,

Gisela Kristoff; Luis C. Cacciatore; Noemí R. Verrengia Guerrero; Adriana C. Cochón

2011-01-01

63

Habitat preference of freshwater snails in relation to environmental factors and the presence of the competitor snail Melanoides tuberculatus (Müller, 1774).  

PubMed

Our objective is to evaluate the habitat preference of freshwater snails in relation to environmental factors and the presence of the competitor snail Melanoides tuberculatus. In the first phase, snails was collected at 12 sites. This sampling sites presented a degree of organic input. In the second phase 33 sampling sites were chosen, covering a variety of lotic and lentic environments. The snail species found at Guapimirim, state of Rio de Janeiro, displayed a marked habitat preference, specially in relation to the physical characteristics of each environment. Other limiting factors for snail distribution at the studied lotic environments were the water current velocity and the amount of organic matter, mainly to Physa marmorata, M. tuberculatus, and Biomphalaria tenagophila. The absence of interactions between M. tuberculatus and another snails could be associated to the distinct spatial distribution of those species and the instability of habitats. This later factor may favor the coexistence of M. tuberculatus with B. glabrata by reduction of population density. In areas of schistosomiasis transmission some habitat modification may add to the instability of the environment, which would make room for the coexistence of M. tuberculatus and Biomphalaria spp. In this way, some of the usual measures for the control of snail hosts would prevent the extinction of populations of Biomphalaria spp. by M. tuberculatus in particular habitats. PMID:16021304

Giovanelli, Alexandre; da Silva, Cesar Luiz Pinto Ayres Coelho; Leal, Geórgia Borges Eccard; Baptista, Darcílio Fernandes

2005-04-01

64

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

PubMed Central

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

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

2007-01-01

65

Garden snail  

NSDL National Science Digital Library

One reason why the snail is considered to be a mollusk is because it doesn't have any legs. It moves around on its belly, which is actually called the foot. Some snails live in water while others only live on land.

Danielle N/A (None;)

2007-07-28

66

Snail Trails  

ERIC Educational Resources Information Center

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

Galus, Pamela

2002-01-01

67

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

PubMed

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

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

2009-09-01

68

Snails home  

NASA Astrophysics Data System (ADS)

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

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

2014-06-01

69

Schistosomes and snails: a molecular encounter  

PubMed Central

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

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

2014-01-01

70

Identification of genes involved in interactions between Biomphalaria glabrata and Schistosoma mansoni by suppression subtractive hybridization.  

PubMed

Biomphalaria glabrata is an intermediate snail host for Schistosoma mansoni, a medically important schistosome. In order to identify transcripts involved in snail-schistosome interactions, subtractive cDNA libraries were prepared, using suppression subtractive hybridization (SSH) between a parasite-exposed schistosome-resistant and a susceptible strain of B. glabrata, and also between schistosome-exposed and unexposed snails from the resistant snail line. Separate libraries were made from both haemocytes and the haemopoietic organ. Subtraction was performed in both directions enriching for cDNAs differentially expressed between parasite-exposed resistant and susceptible samples and up or down-regulated in the resistant line after challenge. The resulting eight libraries were screened and eight genes, differentially expressed between the haemocytes of resistant and susceptible snail strains, were identified and confirmed with reverse transcriptase PCR, including two transcripts expected to be involved in the stress response mechanism for regulating the damaging oxidative burst pathways involved in cytotoxic killing of the parasite: the iron-storage and immunoregulatory molecule, ferritin, and HtrA2, a serine protease involved in the cellular stress response. Transcripts with elevated levels in the resistant strain, had the same expression patterns in the subtracted libraries and unsubtracted controls; higher levels in exposed resistant snails compared to susceptible ones and down-regulated in exposed compared with unexposed resistant snails. Differential expression of two of the transcripts with no known function from the susceptible strain, was independently confirmed in a repeat exposure experiment. PMID:17081633

Lockyer, Anne E; Spinks, Jennifer; Noble, Leslie R; Rollinson, David; Jones, Catherine S

2007-01-01

71

Snail Shell  

USGS Multimedia Gallery

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

72

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

PubMed

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 exhibits a remarkable degree of intraspecific polymorphism. Low stringency-PCR using primers for 18S rRNA permitted 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 Ddel 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. PMID:9921330

Vidigal, T H; Dias Neto, E; Spatz, L; Nunes, D N; Pires, E R; Simpson, A J; Carvalho, O S

1998-01-01

73

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

PubMed

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

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

2012-01-01

74

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

Microsoft Academic Search

Snail surveys were carried out in various parts of Mali. All areas surveyed are part of the Niger basin being either affluents\\u000a or irrigation schemes fed by this river. The snail species present varied greatly between areas. The following potential hosts\\u000a of schistosomes were recorded: Biomphalaria pfeifferi, Bulinus truncatus, B. globosus, B. umbilicatus, B. forskalii and B. senegalensis.\\u000a \\u000a In the

Henry Madsen; Godefroy Coulibaly; Peter Furu

1987-01-01

75

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

Microsoft Academic Search

We collected six species of freshwater snails from Dominica, including Biomphalaria kuhniana (Clessin, 1883), Gundlachia radiata (Guilding, 1828), Helisoma (=Planorbella) trivolvis (Say, 1817), Melanoides tuberculata (Müller, 1774), Neritina punctulata Lamarck, 1816, and Physa marmorata Guilding, 1828. Our collections indicate that un-reported species such as G. radiata and H. trivolvis are established on Dominica, West Indies. We tested a limited number

Will K. Reeves; Robert T. Dillon; Gregory A. Dasch

2008-01-01

76

Freshwater snails and Schistosomiasis mansoni in the state of Rio de Janeiro, Brazil: IV - Sul Fluminense Mesoregion.  

PubMed

In this paper, the forth of a series dealing with the survey of freshwater gastropods of the state of Rio de Janeiro, the results of collections carried out in the Sul Fluminense Mesoregion from 2000 to 2002 are presented and revealed the occurrence of 18 species: Antillorbis nordestensis; Biomphalaria glabrata; Biomphalaria peregrina; Biomphalaria straminea; Biomphalaria tenagophila; Drepanotrema anatinum; Drepanotrema cimex; Drepanotrema lucidum; Ferrissia sp.; Gundlachia ticaga; Gundlachia sp.; Heleobia sp.; Lymnaea columella; Melanoides tuberculatus; Physa acuta; Physa marmorata; Pomacea sordida and Pomacea sp. As to the snail hosts of Schistosoma mansoni the most frequent species was B. tenagophila, found in all municipalities surveyed, except Parati. Besides new records the present study extends the distribution of B. peregrina and B. straminea in the state. No specimens were found harbouring larval forms of S. mansoni although different kinds of cercariae had been observed. An account about the current schistosomiasis transmission sites in this Mesoregion is presented as well. PMID:15273799

Thiengo, Silvana C; Mattos, Aline C; Boaventura, M Fernanda; Fernandez, Monica A

2004-05-01

77

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

ERIC Educational Resources Information Center

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

Tocatlian, Jacques

1991-01-01

78

Schistosomiasis in the southern region of Oman: vector snails and serological identification of patients in several locations.  

PubMed

The snail Biomphalaria arabica is apparently ubiquitous in the south of Oman (Dhofar province). Snails bred in the laboratory were susceptible to infection with miracidia of Schistosoma mansoni (Puerto Rican strain). The snail Bulinus wrighti, a potential intermediate host of S. haematobium, was found for the first time in Dhofar. Human sera from five localities had antibodies against adult worm antigens and in particular against Sm31/32. The prevalence of seropositive patients was 28% of 47 farm workers, 12% of 99 out-patients from a clinic and 1% of 389 children from four localities. Autochthonous transmission of schistosomiasis in Dhofar is discussed. PMID:8064941

Idris, M A; Ruppel, A; Numrich, P; Eschlbeck, A; Shaban, M A; Diesfeld, H J

1994-08-01

79

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

PubMed

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

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

2015-01-01

80

Snail control in urban sites in Brazil with slow-release hexabutyldistannoxane and pentachlorophenol*  

PubMed Central

Slow release formulations of hexabutyldistannoxane (TBTO) and pentachlorophenol (PCP) were tested for the control of Biomphalaria tenagophila in 52 urban sites in Rio de Janeiro. TBTO acted faster and lasted longer than PCP and at 15 g/m2 it eliminated snails from 76% of the treated sites for 1 year. Water pollution and rate of flow had no significant influence on the molluscicidal properties of either compound, but alkalinity lowered the activity of TBTO. Failure to control snail populations was due mainly to human interference and to the non-treatment of adjacent breeding sites that were temporarily dry and therefore overlooked. PMID:1088356

Toledo, J. V.; Da Silva, C. S. Monteiro; Bulhões, M. S.; Leme, L. A. Paes; Netto, J. A. Da Silva; Gilbert, B.

1976-01-01

81

Apple Snails (Ampullariidae)  

NSDL National Science Digital Library

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

Ghesquiere, Stijn A.

82

Development of species-specific primers for identification of Biomphalaria arabica, the intermediate host of Schistosoma mansoni in Saudi Arabia.  

PubMed

Schistosoma mansoni is mediated through the intermediate host Biomphalaria arabica which lives in Saudi Arabia. Molecular characterization and identification of this intermediate host are important for epidemiological studies of schistosomiasis. The present work aimed to determine the molecular variations among the populations of B. arabica found in Southern part of Saudi Arabia, and to develop species-specific primers for identification of these snails as a first step in the development of multiplex PCR for simultaneously identifying the snails and diagnosing its infections in a single step. Five populations of Saudi B. arabica snails were collected from freshwater bodies. Three populations were collected from Asser and two populations were collected from AL-Baha. Genomic DNA was extracted from snails and was amplified using five different RAPD-PCR primers. The banding patterns of amplified materials by primers P1 and P5 were identical in all populations. However, the rest primers displayed intra-specific differences among populations with variable degrees. Largest sizes of RAPD-PCR products were cloned into TA cloning vector as a preparatory step for DNA sequence analysis. After sequencing, similarity searches of obtained DNA sequences revealed that there are no similar sequences submitted to genebank data bases and its associated banks. The results obtained will be helpful in the development of simultaneous identification of B. arabica snails and diagnosis of S. mansoni infection within it in a single step by an implementation of multiplex PCR. PMID:24596501

Al-Quraishy, Saleh A; Bin Dajem, Saad M; Mostafa, Osama M; Ibrahim, Essam H; Al-Qahtani, Ahmed

2014-01-01

83

Molluscicidal activities of six species of Bignoniaceae from north-eastern Brazil, as measured against Biomphalaria glabrata under laboratory conditions.  

PubMed

The molluscicidal profile and brine-shrimp bio-activity of the ethanolic extracts of plants from the Bignoniaceae family were determined. The six extracts investigated were of the stems of Melloa quadrivalvis and Tabebuia aurea, and whole plants of Adenocalymma comosum, Arrabidaea parviflora, Cuspidaria argentea and Clytostoma binatum. When tested in the laboratory, with Biomphalaria glabrata as the test snail, all six extracts gave median lethal concentrations (9-54 microg/ml) that fell well below the upper threshold, of 100 mug/ml, set for a potential molluscicide by the World Health Organization. PMID:17524251

Silva, T M S; Da Silva, T G; Martins, R M; Maia, G L A; Cabral, A G S; Camara, C A; Agra, M F; Barbosa-Filho, J M

2007-06-01

84

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

PubMed Central

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

McCreesh, Nicky; Booth, Mark

2014-01-01

85

Analysis of Circulating Haemocytes from Biomphalaria glabrata following Angiostrongylus vasorum Infection Using Flow Cytometry  

PubMed Central

Angiostrongylus vasorum is an emerging parasite of dogs and related to carnivores that have an indirect life cycle, with a wide range of terrestrial and aquatic gastropods as the obligatory intermediate host. Unfortunately, the relationship between A. vasorum and their snail hosts remains poorly understood. Circulating haemocytes are the main line of cellular defence involved in the destruction of helminths in snails. Aiming to further characterize the haemocyte subsets in Biomphalaria snails, we have performed a flow cytometric analysis of whole haemolymph cellular components using a multiparametric dual colour labelling procedure. Our findings demonstrated that B. glabrata infected with A. vasorum have two major circulating haemocyte subsets, referred to as small and large haemocytes. Differences in the cell proportion occurred over time. The development of better invertebrate infection control strategies would certainly result in the better control of human diseases caused by other species of the genus Angiostrongylus. Such knowledge will assist in the establishment of novel control strategies aimed at parasites that use molluscs as intermediate hosts and clarify new aspects of the parasite-host relationship regarding cell recognition and activation mechanisms, which are also found in the innate response of vertebrates. PMID:22545202

Barçante, Thales A.; Barçante, Joziana M. P.; Fujiwara, Ricardo T.; Lima, Walter S.

2012-01-01

86

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

PubMed

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

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

2014-01-01

87

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

PubMed Central

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

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

2013-01-01

88

Effect of water temperature and population density on the population dynamics of Schistosoma mansoni intermediate host snails.  

PubMed

BackgroundMathematical models can be used to identify areas at risk of increased or new schistosomiasis transmission as a result of climate change. The results of these models can be very different when parameterised to different species of host snail, which have varying temperature preferences. Currently, the experimental data needed by these models are available for only a few species of snail. The choice of density-dependent functions can also affect model results, but the effects of increasing densities on Biomphalaria populations have only previously been investigated in artificial aquariums.MethodsLaboratory experiments were conducted to estimate Biomphalaria sudanica mortality, fecundity and growth rates at ten different constant water temperatures, ranging from 13-32°C. Snail cages were used to determine the effects of snail densities on B. sudanica and B. stanleyi mortality and fecundity rates in semi-natural conditions in Lake Albert.Results B. sudanica survival and fecundity were highest at 20°C and 22°C respectively. Growth in shell diameter was estimated to be highest at 23°C in small and medium sized snails, but the relationship between temperature and growth was not clear. The fecundity of both B. sudanica and B. stanleyi decreased by 72-75% with a four-fold increase in population density. Increasing densities four-fold also doubled B. stanleyi mortality rates, but had no effect on the survival of B. sudanica.ConclusionsThe optimum temperature for fecundity was lower for B. sudanica than for previously studied species of Biomphalaria. In contrast to other Biomphalaria species, B. sudanica have a distinct peak temperature for survival, as opposed to a plateau of highly suitable temperatures. For both B. stanleyi and B. sudanica, fecundity decreased with increasing population densities. This means that snail populations may experience large fluctuations in numbers, even in the absence of any external factors such as seasonal temperature changes. Survival also decreased with increasing density for B. stanleyi, in contrast to B. sudanica and other studied Biomphalaria species where only fecundity has been shown to decrease. PMID:25388819

McCreesh, Nicky; Arinaitwe, Moses; Arineitwe, Wilber; Tukahebwa, Edridah M; Booth, Mark

2014-11-12

89

Participation of N-acetyl-D-glucosamine carbohydrate moieties in the recognition of Schistosoma mansoni sporocysts by haemocytes of Biomphalaria tenagophila.  

PubMed

Lectin-carbohydrate binding may be involved in the recognition of Schistosoma mansoni sporocysts by haemocytes of Biomphalaria; therefore, we tested if this interaction is associated with snail resistance against Schistosoma infection. In vitro data showed that most of the S. mansoni sporocysts cultured with haemocytes from Biomphalaria glabrata BH, a highly susceptible snail strain, had a low number of cells that adhered to their tegument and a low mortality rate. Moreover, the addition of N-acetyl-D-glucosamine (GlcNAc) did not alter this pattern of adherence and mortality. Using haemocytes and haemolymph of Biomphalaria tenagophila Cabo Frio, we observed a high percentage of sporocysts with adherent cells, but complete encapsulation was not detected. Low concentrations of GlcNAc increased haemocyte binding to the sporocysts and mortality, which returned to basal levels with high concentrations of the carbohydrate. In contrast, haemocytes plus haemolymph from B. tenagophila Taim encapsulated cellular adhesion index of level 3 and destroyed over 30% of the S. mansoni sporocysts in culture. Interestingly, the addition of GlcNAc, but not mannose, to the culture medium resulted in the significant inhibition of cellular adhesion to the parasite tegument and the reduction of parasite mortality, suggesting that GlcNAc carbohydrate moieties are important to the recognition of S. mansoni by B. tenagophila Taim. PMID:22124562

Martins-Souza, Raquel Lopes; Pereira, Cintia Aparecida Jesus; Rodrigues, Leonardo; Araújo, Emília Souza; Coelho, Paulo Marcos Zech; Corrêa Jr, Ary; Negrão-Corrêa, Deborah

2011-11-01

90

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

PubMed

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

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

2004-11-01

91

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

PubMed

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

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

2009-03-01

92

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

PubMed Central

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

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

2013-01-01

93

All About Snails  

NSDL National Science Digital Library

This website introduces younger students to snails. Topics include their physical characteristics and living habits, diet, reproduction, locomotion, life history, predators, and many others. There are also links to additional material on snails, including lesson plans, stories, poems, and songs, clip-art, art and craft activties, and other resources.

2001-11-01

94

Snail Shell Science.  

ERIC Educational Resources Information Center

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

Matthews, Catherine

1992-01-01

95

The Classroom Animal: Snails.  

ERIC Educational Resources Information Center

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

Kramer, David S.

1985-01-01

96

The plasma proteins of Biomphalaria glabrata in the presence and absence of Schistosoma mansoni.  

PubMed

Snail plasma serves as both a sink for metabolites and a source of nutrients for parasites developing within their intermediate hosts. It also contains molecules involved in immunological events like non-self recognition, phagocytosis and encapsulation. In this study we present improved protocols for the separation and partial characterization of plasma proteins of schistosome-susceptible and resistant strains of Biomphalaria glabrata. Within each strain, the plasma of snails 12, 24, 48 and 72 h post-exposure to Schistosoma mansoni and of non-exposed snails was compared. Protein concentrations in hemolymph of all snail strains, non-exposed or parasite-exposed, were about 29 mg/mL and were not found to differ significantly. The dominant plasma molecule (80-85%) is extracellular hemoglobin (Hb) with a native mass of > 1 M Da, and subunits of 190 kDa. It is the only protein bearing heme as shown after separation by native-PAGE and LDS-PAGE. The relatively large amounts of Hb and its large size cause problems if native plasma components are to be separated in PAGE. To obtain satisfactory separation, we used short-term ultracentrifugation to deplete Hb from plasma without qualitative loss of other proteins. Using this methodology, we have examined proteins by native polyacrylamide gel electrophoresis, in the presence of SDS or LDS only or SDS and mercaptoethanol, and by isoelectric focusing. Proteins have been detected in gels by silver stains and staining for heme groups, and, after transfer to membranes, by means of lectins and neoglycoproteins. Molecular weights of plasma proteins range between 10 and > 450 kDa, and isoelectric points are from pH 4 to 9.4. All strains show similar protein patterns, although minor inter- and intrastrain differences occur. These differences are quantitative rather than qualitative, not consistent, and cannot be correlated with the snail's ability to effectively attack and kill S. mansoni sporocysts. In all snail strains, plasma proteins remained qualitatively stable during 3 days after exposure to S. mansoni. New proteins were not evident, and none was lost as a consequence of exposure to parasites. Our new Hb-depletion technique is an excellent approach to separate and examine Biomphalaria plasma proteins in their native state. The use of lectins to probe for the presence of carbohydrates showed that the majority of plasma proteins is glycosylated. Mannose, galactose, and N-acetylgalactosamine are their major carbohydrate components; fucose was not detected. Several lectins apparently in the molecular mass range of 330-500 and 56-135 kDa with major carbohydrate-specificities for N-acetyl-galactosamine, N-acetylglucosamine, mannose, glucose, galactose and fucose were detected in the plasma of both resistant and susceptible snails by using neoglycoproteins as probes. PMID:8595817

Zelck, U E; Becker, W; Bayne, C J

1995-01-01

97

Toxicity of Euphorbia milii latex and niclosamide to snails and nontarget aquatic species.  

PubMed

The toxicity of Euphorbia milii molluscicidal latex and niclosamide (NCL) to target snails (Biomphalaria glabrata and Biomphalaria tenagophila) and nontarget aquatic organisms is evaluated. Planorbidae snails were killed by very low concentrations of lyophilized latex (48-h LC(50), mg/L: B. glabrata, 0.12; B. tenagophila, 0.09; Helisoma duryi, 0.10). Latex was less toxic (48-h LC(50) or EC(50), mg/L) to oligochaeta (Tubifex tubifex, 0.31), planktonic crustacea (Daphnia similis, 0.38; C. dubia, 1.07; Artemia sp., 0.93), and fishes (Danio rerio, 0.96; Poecilia reticulata, 1. 39), and considerably less toxic to Ampullariidae snails (Pomacea sp. , 10.55) and frog tadpoles (Rana catesbeiana, 7.50). Latex (up to 100 mg/L) was not toxic to bacteria (P. putida and V. fischeri), algae (Selenastrum capricornutum and Chlorella vulgaris), and mosquito larvae (Anopheles albitarsis, Aedes aegypti, Aedes fluviatilis). NCL was very toxic (48-h LC(50) or EC(50), mg/L) to Planorbidae snails (B. glabrata, 0.15, B. tenagophila, 0.13; H. duryi, 0.10), T. tubifex (0.11), crustacea (D. similis, 0.19; Ceriodaphnia dubia, 0.47; Artemia sp. 0.18), fishes (D. rerio, 0.25; P. reticulata, 0.29), R. catesbeiana (0.16), and Pomacea sp. (0.76). NCL was toxic to bacteria, algae (96-h IC(50), mg/L: S. capricornutum, 0.34; C. vulgaris, 1.23) and slightly toxic to mosquito larvae. In conclusion, E. milii latex, as compared with the reference molluscicide niclosamide, presents a higher degree of selectivity toward snails which are intermediate hosts of Schistosoma trematodes. PMID:10903832

Oliveira-Filho, E C; Paumgartten, F J

2000-07-01

98

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

PubMed Central

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

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

2013-01-01

99

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

PubMed Central

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

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

2014-01-01

100

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

PubMed

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

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

2014-01-01

101

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

PubMed Central

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

Malek, Emile A.; File, Sharon K.

1971-01-01

102

New insights into the amphibious life of Biomphalaria glabrata and susceptibility of its egg masses to fungal infection.  

PubMed

The air-breathing snail Biomphalaria glabrata proliferates in stagnant freshwater, and nothing is known about the survival of eggs in intermittently (rather than perpetually) wet habitats. In the present study their egg masses matured, and juveniles subsequently eclosed and were mobile in a stable water film of transitory habitats simulated by two different simple test devices described here. The viability of eggs maintained in an unstable film however, was diminished. The maturation of egg masses in a water film or in water was significantly prevented by the entomopathogenic fungi Beauveria bassiana and Metarhizium anisopliae. The efficiency depended on the fungal propagule and test environment. Hyphal bodies were more effective against egg masses than conidia. This appears to be a first report of activity of either entomopathogen against a mollusc. Both devices offer accurate and reproducible conditions to test both biological questions and the effects of substances or pathogens against B. glabrata egg masses in water films. PMID:25576771

Duarte, Glennyha F; Rodrigues, Juscelino; Fernandes, Éverton K K; Humber, Richard A; Luz, Christian

2015-02-01

103

Reduced susceptibility of a Biomphalaria tenagophila population to Schistosoma mansoni after introducing the resistant Taim/RS strain of B. tenagophila into Herivelton Martins stream.  

PubMed

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

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

2014-01-01

104

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

PubMed Central

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

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

2014-01-01

105

Lichen endozoochory by snails.  

PubMed

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

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

2011-01-01

106

Small Snails, Enormous Elephants  

NSDL National Science Digital Library

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

Chicago Children's Museum

2011-01-01

107

Lichen Endozoochory by Snails  

PubMed Central

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

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

2011-01-01

108

Eye to Eye With Garden Snails  

NSDL National Science Digital Library

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

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

1994-07-30

109

Inquiry, Land Snails, and Environmental Factors.  

ERIC Educational Resources Information Center

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

Barrow, Lloyd H.; Krantz, Patrick D.

2002-01-01

110

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

PubMed Central

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

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

2008-01-01

111

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

PubMed

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

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

2013-10-01

112

Characterization of ?-L-fucosidase and other digestive hydrolases from Biomphalaria glabrata.  

PubMed

Schistosoma mansoni is one of the major agents of the disease Schistosomiasis, which is one of the major global public health concerns. Biomphalaria glabrata is an obligate intermediate mollusc host of S. mansoni. Although the development of S. mansoni occurs in the snail hepatopancreas, studies that focus on this organ remain limited. In this study, we biochemically identified five distinct carbohydrases (amylase, maltase, ?-glucosidase, trehalase, and ?-L-fucosidase), lipases, and peptidases in the B. glabrata hepatopancreas and focused on the isolation and characterization of the activity of ?-L-fucosidase. The isolated ?-L-fucosidase has a molecular mass of 141kDa, an optimum pH of 5.8, and is inhibited by Tris, fucose, and 1-deoxyfuconojirimycin. B. glabrata ?-L-fucosidase is an exoglycosidase that can hydrolyze the natural substrate fucoidan to fucose residues. It presented Km values of 48.4?M to 4-Methylumbelliferyl ?-L-fucopyranoside and 0.55mM to p-nitrophenyl-?-L-fucopyranoside. Thus, ?-L-fucosidase has a high activity in the hepatopancreas of B. glabrata, and the differential expression of this enzyme between susceptible and resistant strains indicates that besides its digestive role, ?-L-fucosidase may also be important in host/parasite interactions. PMID:25218034

Perrella, Natalia N; Cantinha, Rebeca S; Nakano, Eliana; Lopes, Adriana R

2015-01-01

113

Biomphalysin, a new ? pore-forming toxin involved in Biomphalaria glabrata immune defense against Schistosoma mansoni.  

PubMed

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

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

2013-03-01

114

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

PubMed Central

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

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

2013-01-01

115

Polymorphism in pleistocene land snails.  

PubMed

Under suitable conditions the colors and patterns of the shells of land snails may be preserved for thousands of years. In a late Pleistocene population of Limicolaria martensiana all the major color forms that occur in modern living snails may be distinguished, and the basic polymorphism is at least 8,000 to 10,000 year old. PMID:17830234

Owen, D F

1966-04-01

116

Glow-Worms nu Snails  

Microsoft Academic Search

YOUR correspondent, Mr. R. S. Newall, has unconsciously reversed the natural condition of affairs in his note (NATURE, vol. xx. p. 197). The heading should have been as above Glow-worms devour snails, which are their natural food. The particular snail in question had probably been attacked by the one of the glow-worms, which had left some of its phosphorescent matter

R. McLachlan

1879-01-01

117

Molecular characterisation of intermediate snail hosts and the search for resistance genes.  

PubMed

The relationship between schistosomes and their intermediate hosts is an extremely intricate one with strains and species of the parasite depending on particular species of snail, which in turn may vary in their susceptibility to the parasites. In order to gain a better understanding of the epidemiology of the disease we have been investigating the use of molecular markers for snail identification and for studying host-parasite relationships. In this paper we will draw on examples concerning schistosomiasis in West and East Africa to illustrate how a molecular analysis can be used as part of a "total evidence" approach to characterisation of Bulinus species and provide insights into parasite transmission. Particular emphasis is given to ribosomal RNA genes (rRNA), random amplified polymorphic DNA (RAPDs) and the mitochondrial gene cytochrome oxidase I (COI). Snails resistant to infection occur naturally and there is a genetic basis for this resistance. In Biomphalaria glabrata resistance to Schistosoma mansoni is known to be a polygenic trait and we have initiated a preliminary search for snail genomic regions linked to, or involved in, resistance by using a RAPD based approach in conjunction with progeny pooling methods. We are currently characterising a variety of STSs, (sequence tagged sites) associated with resistance. These can be used for local linkage and interval mapping to define genomic regions associated with the resistance trait. The development of such markers into simple dot-blot or specific PCR-based assays may have a direct and practical application for the identification of resistant snails in natural populations. PMID:9921331

Rollinson, D; Stothard, J R; Jones, C S; Lockyer, A E; de Souza, C P; Noble, L R

1998-01-01

118

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

PubMed Central

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

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

2012-01-01

119

Interaction of Schistosoma mansoni Sporocysts and Hemocytes of Biomphalaria  

PubMed Central

Human infection by Schistosoma mansoni affects more than 100 million people worldwide, most often in populations of developing countries of Africa, Asia, and Latin America. The transmission of S. mansoni in human populations depends on the presence of some species of Biomphalaria that act as an intermediate host. The compatibility between S. mansoni and its intermediate host is influenced by behavioral, physiological, and genetical factors of the mollusc and the parasite. The susceptibility level of the mollusc has been attributed to the capacity of internal defense system (IDS)—hemocytes and soluble components of the hemolymph—to recognize and destroy the parasite, and this will be the center of interest of this paper. The schistosome-resistant Biomphalaria can be an alternative strategy for the control of schistosomiasis. PMID:22811885

Negrão-Corrêa, D.; Mattos, A. C. A.; Pereira, C. A. J.; Martins-Souza, R. L.; Coelho, P. M. Z.

2012-01-01

120

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

SciTech Connect

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

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

2008-08-20

121

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

PubMed Central

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

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

2014-01-01

122

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

PubMed Central

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

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

2009-01-01

123

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

PubMed Central

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

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

2006-01-01

124

APPLE SNAILS AS DISEASE VECTORS  

Technology Transfer Automated Retrieval System (TEKTRAN)

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

125

Freshwater snails and schistosomiasis mansoni in the state of Rio de Janeiro, Brazil: V -- Norte Fluminense Mesoregion.  

PubMed

In this paper, the fifth of a series dealing with the survey of freshwater gastropods of the state of Rio de Janeiro, the results of collections carried out in the Norte Fluminense Mesoregion from 2002 to 2003 are presented and revealed the occurrence of 19 species: Antillorbis nordestensis; Burnupia sp.; Biomphalaria tenagophila; Drepanotrema anatinum; Drepanotrema cimex; Drepanotrema depressissimum; Drepanotrema lucidum; Ferrissia sp.; Gundlachia ticaga; Gundlachia sp.; Heleobia sp.; Hebetancylus moricandi; Idiopyrgus sp.; Lymnaea columella; Melanoides tuberculatus; Physa acuta; Physa marmorata; Pomacea sordida, and Pomacea sp. Concerning the snail hosts of Schistosoma mansoni only B. tenagophila was found, in contrast with other previuosly studied mesoregions.No specimens were found harbouring larval forms of S. mansoni although different kinds of cercariae had been observed. An account about the current schistosomiasis transmission sites in this Mesoregion is presented as well. PMID:15486644

Thiengo, Silvana C; Mattos, Aline C; Boaventura, M Fernanda; Loureiro, Márcio S; Santos, Sonia B; Fernandez, Monica A

2004-01-01

126

Freshwater snails and schistosomiasis mansoni in the state of Rio de Janeiro, Brazil: VI--Noroeste Fluminense Mesoregion.  

PubMed

In this paper, the last of a series dealing with the survey of freshwater gastropods of the state of Rio de Janeiro, the results of collections carried out in the Noroeste Fluminense Mesoregion from 2002 to 2005 are presented and revealed the occurrence of 20 species: Antillorbis nordestensis; Biomphalaria glabrata; B. straminea; B. tenagophila; Drepanotrema anatinum; D. cimex; D. depressissimum; D. lucidum; Ferrissia sp.; Gundlachia ticaga; Gundlachia sp.; Heleobia sp.; Idiopyrgus sp.; Lymnaea columella; Melanoides tuberculatus; Physa acuta; P. marmorata; Plesiophysa guadeloupensis; Pomacea lineata; and Pomacea sp. Concerning the snail hosts of schistosomiasis the three natural vectors were identified and, although no specimens were found harbouring larval forms of Schistosoma mansoni, different kinds of cercariae had been observed. PMID:17308776

Thiengo, Silvana C; Mattos, Aline C; Santos, Sonia B; Fernandez, Monica A

2006-09-01

127

F-LE Snail Invasion  

NSDL National Science Digital Library

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

128

Representation of an immune responsive gene family encoding fibrinogen-related proteins in the freshwater mollusc Biomphalaria glabrata, an intermediate host for Schistosoma mansoni  

PubMed Central

Fibrinogen-related proteins (FREPs) are found in the hemolymph of the freshwater snail Biomphalaria glabrata, are up-regulated following exposure to digenetic trematode parasites, and bind to trematode larval surfaces, suggestive of a role in internal defense. Southern blot and degenerate-polymerase chain reaction (PCR) analyses were undertaken to better understand the diversity of the FREP-encoding gene family. Probes corresponding to the N-terminal IgSF domains of specific FREP gene subfamilies (FREPs 2, 3, 4, 7, 12 and 13) revealed between 1 to 8 loci per subfamily on Southern blots. Probes representing the relatively conserved C-terminal fibrinogen domain of FREPs bound many sequences in Southern blots of genomic DNA from B. glabrata, and from two related gastropod species, Biomphalaria pfeifferi and Helisoma trivolvis. Using degenerate-PCR, we obtained 42 unique fibrinogen-encoding sequences from 180 clones derived from a single individual of the M-line strain of B. glabrata, further supporting the notion of their abundant representation in the B. glabrata genome. The fibrinogen-encoding sequences of FREPs encoding one or two IgSF domains tended to separate into distinct clades, but bootstrap support for this separation was low. A novel category of fibrinogen-encoding sequence was also revealed. This study provides the approximate number of gene copies in several FREP subfamilies, confirms the existence of a diverse FREP gene family, reports additional unusual sequences encoding fibrinogen-like molecules, and provides further justification to explore the functional roles of FREPs in both B. glabrata and B. pfeifferi, both important intermediate hosts of the human pathogen, Schistosoma mansoni. PMID:15474308

Zhang, Si-Ming; Loker, Eric S.

2013-01-01

129

Production of apple snail for space diet  

NASA Astrophysics Data System (ADS)

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

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

130

Controlling slugs and snails in orchids  

Technology Transfer Automated Retrieval System (TEKTRAN)

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

131

Inquiry, Land Snails, and Environmental Factors  

ERIC Educational Resources Information Center

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

Barrow, Lloyd H.; Krantz, Patrick D.

2005-01-01

132

Freshwater snails and schistosomiasis mansoni in the state of Rio de Janeiro, Brazil: V - Norte fluminense mesoregion  

Microsoft Academic Search

In this paper, the forth of a series dealing with the survey of freshwater gastropods of the state of Rio de Janeiro, the results of collections carried out in the Sul Fluminense Mesoregion from 2000 to 2002 are presented and revealed the occurrence of 18 species: Antillorbis nordestensis; Biomphalaria glabrata; Biomphalaria peregrina; Biomphalaria straminea; Biomphalaria tenagophila; Drepanotrema anatinum; Drepanotrema cimex;

Silvana C Thiengo; Aline C Mattos; M Fernanda Boaventura; Monica A Fernandez; Sonia B Santos

2004-01-01

133

Non-random organization of the Biomphalaria glabrata genome in interphase Bge cells and the spatial repositioning of activated genes in cells co-cultured with Schistosoma mansoni  

PubMed Central

Biomphalaria glabrata is a major intermediate host for the parasitic trematode Schistosoma mansoni, a causative agent of human schistosomiasis. To decipher the molecular basis of this host-parasite interaction, the Bge embryonic cell line provides a unique in vitro model system to assess whether interactions between the snail and parasite affect the cell and genome biology in either organism. The organisation of the B. glabrata genome in Bge cells was studied using image analysis through positioning territories of differently sized chromosomes within cell nuclei. The snail chromosome territories are similar in morphology as well as in non-random radial positioning as those found in other derived protostome and deuterostome organisms. Specific monitoring of four gene loci, piwi, BgPrx, actin and ferritin, revealed non-random radial positioning of the genome. This indicates that specific parts of the snail genome reside in reproducible nuclear addresses. To determine whether exposure to parasite is reflected in genome organization, the interphase spatial positioning of genes was assessed after co-culturing Bge cells with either normal or irradiation attenuated miracidia for 30 min to 24 h. The loci of actin and ferritin, genes that are up-regulated in the snail when subjected to infection, were visualized by fluorescence in situ hybridisation (FISH) and their radial nuclear positions i.e. their position in the interphase nucleus with respect to the nuclear edge/envelope, mapped. Interestingly, large scale gene repositioning correlated to temporal kinetics of gene expression levels in Bge cells co-cultured with normal miracidia while irradiated parasites failed to elicit similar gene expression or gene loci repositioning as demonstrated using the ferritin gene. This indicates that normal but not attenuated schistosomes provide stimuli that evoke host responses that are reflected in the host’s nuclear architecture. We believe that this is not only the first time that gene-repositioning studies have been attempted in a mollusc but also demonstrates a parasite influencing the interphase genome organisation of its host. PMID:20849859

Knight, Matty; Ittiprasert, Wannaporn; Odoemelam, Edwin C.; Adema, Coen M; Miller, André; Raghavan, Nithya; Bridger, Joanna M.

2011-01-01

134

Tentacular function in snail olfactory orientation  

Microsoft Academic Search

1.The olfactory orienting behavior of the terrestrial snailAchatina fulica was studied in intact animals, in animals with bilateral lesions of either the anterior tentacles or the posterior tentacles, and in animals with unilateral lesions of the posterior tentacles. Tentacular function was evaluated under three different conditions.2.One assay required the snails to locomote upwind in a two-armed olfactometer and enter the

Ronald Chase; Roger P. Croll

1981-01-01

135

[Remarks on the ecological adaptation of the snail aquatic fauna in saline medium of the Dallol ponds. (Republique du Niger) (author's transl)].  

PubMed

Human vesical and intestinal bilharziasis, bovine fasciolosis and paramphistomosis, equine gastrodiscosis and ovine carmyeriosis, are frequent in the Dallols'region, (12 degrees - 13 degrees 30 N. lat. ; 3 degrees E. long.), Republique du Niger, Africa. Dallols are fossil valleys pouring water from late Saharian lakes. They are also tributaries of the Niger River. During the dry season, they become dry and many residual ponds of varied dimensions; from tens feet to one or two miles long, are lying along the valley bottom. The water is sometimes fresh but more frequently salt, (sodium, calcium and potassium, chlorides, sulfates, carbonates and bicarbonate), are in solution of variable proportions. From november to april, the total salt concentration is increasing by high evaporation and the medium becomes non likely to live for aquatic vector snails, Bulinus truncatus, Biomphalaria pfeifferi, Bulinus forskalii, Lymnaea natalensis and Afrogyrus coretus. PMID:1221913

Gretillat, S; Gaston, G

1975-01-01

136

The role of Snail in prostate cancer  

PubMed Central

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

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

2012-01-01

137

Snail1, Snail2, and E47 promote mammary epithelial branching morphogenesis  

PubMed Central

Several E-box-binding transcription factors regulate individual and collective cell migration and enhance the motility of epithelial cells by promoting epithelial-mesenchymal transition (EMT). Here, we characterized the role of a subset of these transcription factors and the EMT proteome in branching morphogenesis of mammary epithelial tissues using a three-dimensional organotypic culture model of the mammary duct. We found that the transcription factors Snail1, Snail2, and E47 were transiently upregulated at branch sites; decreasing the expression of these transcription factors inhibited branching. Conversely, ectopic expression of Snail1, Snail2, and E47 induced branching in the absence of exogenous stimuli. These changes correlated with the expression of mesenchymal markers and repression of E-cadherin, which was essential for branching. Snail1 and Snail2 also promoted cell survival at branch sites, but this was not sufficient to induce branching. These findings indicate that Snail1, Snail2, and E47 can promote collective migration during branching morphogenesis of mammary epithelial tissues through key regulators of EMT. PMID:21610693

Lee, KangAe; Gjorevski, Nikolce; Boghaert, Eline; Radisky, Derek C; Nelson, Celeste M

2011-01-01

138

Snail1 Expression Is Required for Sarcomagenesis12  

PubMed Central

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. PMID:24947186

Alba-Castellón, Lorena; Batlle, Raquel; Francí, Clara; Fernández-Aceñero, María J.; Mazzolini, Rocco; Peña, Raúl; Loubat, Jordina; Alameda, Francesc; Rodríguez, Rufo; Curto, Josué; Albanell, Joan; Muñoz, Alberto; Bonilla, Félix; Ignacio Casal, J.; Rojo, Federico; García de Herreros, Antonio

2014-01-01

139

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

Microsoft Academic Search

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

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

2009-01-01

140

Epigenetic Regulation of EMT: The Snail Story  

PubMed Central

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

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

2014-01-01

141

Glycotope Sharing between Snail Hemolymph and Larval Schistosomes: Larval Transformation Products Alter Shared Glycan Patterns of Plasma Proteins  

PubMed Central

Recent evidence supports the involvement of inducible, highly diverse lectin-like recognition molecules in snail hemocyte-mediated responses to larval Schistosoma mansoni. Because host lectins likely are involved in initial parasite recognition, we sought to identify specific carbohydrate structures (glycans) shared between larval S. mansoni and its host Biomphalaria glabrata to address possible mechanisms of immune avoidance through mimicry of elements associated with the host immunoreactivity. A panel of monoclonal antibodies (mABs) to specific S. mansoni glycans was used to identify the distribution and abundance of shared glycan epitopes (glycotopes) on plasma glycoproteins from B. glabrata strains that differ in their susceptibilities to infection by S. mansoni. In addition, a major aim of this study was to determine if larval transformation products (LTPs) could bind to plasma proteins, and thereby alter the glycotopes exposed on plasma proteins in a snail strain-specific fashion. Plasma fractions (<100 kDa/>100 kDa) from susceptible (NMRI) and resistant (BS-90) snail strains were subjected to SDS-PAGE and immunoblot analyses using mAB to LacdiNAc (LDN), fucosylated LDN variants, Lewis X and trimannosyl core glycans. Results confirmed a high degree of glycan sharing, with NMRI plasma exhibiting a greater distribution/abundance of LDN, F-LDN and F-LDN-F than BS-90 plasma (<100 kDa fraction). Pretreatment of blotted proteins with LTPs significantly altered the reactivity of specific mABs to shared glycotopes on blots, mainly through the binding of LTPs to plasma proteins resulting in either glycotope blocking or increased glycotope attachment to plasma. Many LTP-mediated changes in shared glycans were snail-strain specific, especially those in the <100 kDa fraction for NMRI plasma proteins, and for BS-90, mainly those in the >100 kDa fraction. Our data suggest that differential binding of S. mansoni LTPs to plasma proteins of susceptible and resistant B. glabrata strains may significantly impact early anti-larval immune reactivity, and in turn, compatibility, in this parasite-host system. PMID:22448293

Yoshino, Timothy P.; Wu, Xiao-Jun; Liu, Hongdi; Gonzalez, Laura A.; Deelder, André M.; Hokke, Cornelis H.

2012-01-01

142

Mate desertion in the snail kite  

USGS Publications Warehouse

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

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

1988-01-01

143

What happens when snails get sick?  

NSDL National Science Digital Library

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

American Association for the Advancement of Science (AAAS; )

2004-07-09

144

The Dispersal of Snails by Birds  

Microsoft Academic Search

I WAS present at a meeting of the Malacological Society last May when Dr. Boycott read a very interesting paper, in which he showed how the small snail Balea perversa occurred on trees, walls, and rocks, but not on the ground. The question arose how it got from tree to tree; and in the resulting discussion the fact was brought

T. D. A. Cockerell

1921-01-01

145

[Temporary and permanent breeding sites for Biomphalaria in Jaboatão dos Guararapes, PE].  

PubMed

A malacological survey of permanent and temporary breeding sites was conducted in the Piedade neighborhood of Jaboatão dos Guararapes, Pernambuco, between November 2006 and November 2007, with the aim of determining the malacological fauna at this locality, along with the potential for Schistosomiasis mansoni transmission. In addition to Biomphalaria glabrata (Say, 1818), the molluscs Drepanotrema cimex (Moricand, 1837), Pomacea sp and Melanoides tuberculatus (Muller, 1774) were collected. Among the specimens of Biomphalaria glabrata that were collected, 1,490 were found alive, and 74 (5%) were positive for Schistosoma mansoni. The largest numbers of molluscs collected, and all of the specimens that were positive for Schistosoma mansoni, were collected during the annual rainy season. The presence of larvae of other trematodes infecting the Biomphalaria glabrata molluscs was also observed. These trematodes were from the families Strigeidae and Diplostomatidae and, at first sight, they presented morphology that could lead to confusion with Schistosoma mansoni cercariae. Thus, knowledge of these trematodes becomes essential for the differential diagnosis of the etiological agent for schistosomiasis. PMID:18719804

Souza, Marco Antônio Andrade de; Barbosa, Verônica Santos; Wanderlei, Tereza Neuma Guedes; Barbosa, Constança Simões

2008-01-01

146

The Biological Control of the Snail Hosts of Schistosomes: The Role of Competitor Snails and Biological Invasions  

Microsoft Academic Search

\\u000a Biological control of the snail hosts of schistosomes has been ­considered in the last few decades as an alternative to molluscicides.\\u000a Several groups of organisms have been proposed to control snail hosts, but very few have proven their efficacy in the field.\\u000a Competitor snails can be considered as the most efficient biological control agents and numerous promising laboratory studies\\u000a and

Jean-Pierre Pointier; Patrice David; Philippe Jarne

147

The convoluted evolution of snail chirality  

NASA Astrophysics Data System (ADS)

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

Schilthuizen, M.; Davison, A.

2005-11-01

148

Dragonfly predators influence biomass and density of pond snails.  

PubMed

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

Turner, Andrew M; Chislock, Michael F

2007-08-01

149

Predation Risk and Avoidance Behavior in Two Freshwater Snails  

Microsoft Academic Search

We examined the predator avoidance behav- iors of two common freshwater snails, Physella virgata and Planorbella trivolvis, to the crayfish Procambarus simulans. In response to crayfish predation, the snails crawled above the waterline for several hours, then re- turned to the water. A significant size-dependent rela- tionship existed between crawlout (vertical migration above the waterline) and vulnerability to predation. All

JAMES E. ALEXANDER; ALAN P. COVICH

1991-01-01

150

Barriers, repellents and antifeedants for slug and snail control  

Microsoft Academic Search

Laboratory bioassays were carried out to evaluate the efficacy of various products with potential for slug and snail control in horticulture and agriculture. The products tested were cinnamamide, copper ammonium carbonate, garlic, aluminium and copper foil, a mulch, ureaformaldehyde and the proprietary products SnailBan® and Tex-R® matting. The trials were carried out using the slug Deroceras panormitanum (Lessona and Pollonera,

I Schüder; G. Port; J. Bennison

2003-01-01

151

Images of Minute Minnesota Land Snails Matt Barthel  

E-print Network

at the University of Wisconsin-Green Bay (UWGB). The shells imaged were assigned to species (or subspecies) based Scanning Electron Microscope (SEM). The snails were imaged in N-SEM mode at a vacuum of 10 Pa collection and lab processing of samples containing the shells. Students enrolled in the land snail practicum

Nekola, Jeffrey C.

152

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

E-print Network

Carthusian snail Monacha cartusiana Michigan State University's invasive species factsheets as a prohibited mollusk species by Michigan's plant protection regulations (MDA 2009). Plant hosts A wide variety plants. In addition, invasive snails can potentially transmit plant and animal pathogens and displace

153

Slime-Trail Tracking in the Predatory Snail, Euglandina rosea  

Microsoft Academic Search

Euglandina rosea, a predatory land snail, tracks prey and mates by following slime trails. Euglandina follow slime trails more than 80% of the time, following trails of their own species, but not those of prey snails, in the direction that they were laid. The attractive elements of prey slime are small, water-soluble compounds detected by specialized lip extensions. Although olfaction

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

2003-01-01

154

The Snail Resource of the Eastern Berin9 Sea  

E-print Network

; potential resources, like east- ern Bering Sea snails, are virtually un- known. Several species of large. Japan has harvested snails in the eastern Bering Sea since the early 1970's and there is potential for the development of a U.S. domestic fishery ABSTRACT-A trawl survey in the east- ern Bering Sea outlined

155

Supercharged Snails for Stream Ecology & Water-Quality Studies  

ERIC Educational Resources Information Center

Gill-breathing freshwater snails (Family "Pleuroceridae") are ecologically important, abundant in many streams in the United States, and easy to collect and maintain under classroom conditions. These snails can be used in classroom tests to demonstrate effects of pollutants on aquatic organisms. In more advanced classes, students can cage the…

Stewart, Arthur J.; Ryon, Michael G.

2003-01-01

156

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

PubMed

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

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

2014-01-01

157

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

PubMed Central

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

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

2014-01-01

158

The Mitochondrial Genome of the Venomous Cone Snail Conus consors  

PubMed Central

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

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

2012-01-01

159

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

E-print Network

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

McIntyre, Peter

160

Biological Control of Aquatic Pest Snails by the Black Carp Mylopharyngodon piceus  

Microsoft Academic Search

Some freshwater snail species are severe pests to human health or agriculture. We tested the hypothesis that the fish Mylopharyngodon piceus, the black carp, may serve as a biological control agent of two pest snails, Physella acuta (a bank-dwelling snail) and Melanoides tuberculata (a substratum-dwelling snail). Experiments were carried out in the laboratory and under controlled field conditions. In the

Frida Ben-Ami; Joseph Heller

2001-01-01

161

A magazine providing a snapshot of the latest developments across the chemical Substitutes for snail slime  

E-print Network

. Substitutes for snail slime 20 March 2007 A team of engineers set a small robot climbing walls in order to compare how natural and artificial snail slimes work. A snail's slime acts as both a glue and a lubricant and repair works in natural snail slime and in synthetic slimes based on clay and polymers. They calculated

162

Modeling snail breeding in Bioregenerative Life Support System  

NASA Astrophysics Data System (ADS)

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

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

163

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

PubMed Central

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

Yong, Tai-Soon

2014-01-01

164

Crawling beneath the free surface: Water snail locomotion  

E-print Network

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

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

2008-06-23

165

[Freshwater snails of the Campus of Manguinhos, Oswaldo Cruz Foundation, Rio de Janeiro, RJ].  

PubMed

A survey of freshwater gastropods of the Campus of Manguinhos, Fundação Oswaldo Cruz, Rio de Janeiro, was carried out during the last two years aiming to compare the current species with those found at the beginning of this century. Among 18 breeding sites in 880,000m2 of the surveyed area, 13 showed the following species: Antillorbis nordestensis; Biomphalaria glabrata; Biomphalaria straminea; Lymnaea columella; Melanoides tuberculatus; Physa cubensis; Pomacea glauca and Pomacea lineata. Notably, Biomphalaria tenagophila reported by Lutz in 1918, had disappeared and B. straminea and the Asiatic thiarid M. tuberculatus had been introduced. No specimens infected with Schistosoma mansoni were found. PMID:11460215

Fernandez, M A; Thiengo, S C; Boaventura, M F

2001-01-01

166

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

PubMed Central

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

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

2013-01-01

167

[Influence of EDTA on growth and reproduction of Biomphalaria glabrata (author's transl)].  

PubMed

The influence of EDTA on B. glabrata has been investigated. Newly hatched snails were exposed to concentrations of EDTA from 1 to 64 ppm, and young (diameter of 6 mm) snails to concentrations of 50, 80 and 100 ppm, for periods of 90 days. Fifty percent reduction of egg productivity has been caused by concentration of 16 ppm of EDTA while 50% of mortality has occurred at about 70 ppm. The calcium and iron content both in treated and non-treated young snails have been estimated by atomic absorption photometry. The uptake of calcium was 40, 83 and 90% less for calcium and 37, 77 and 81% less for iron as compared with the untreated group. The calcium content of the shell was 5--15 times greater than that of the soft body, while the iron content of those two parts was in the proportion of 1:1. These proportions were maintained constant in the treated and non-treated groups. The interference of increasing concentrations of EDTA has resulted in the proportional reduction of growth-rate, reproduction rate and of longevity of the exposed snails. PMID:119284

de Souza, C P; Pereira, J P; de Azevedo, M de L; Mendes, N M; Paulini, E

1979-09-01

168

Excretory–secretory proteome of larval Schistosoma mansoni and Echinostoma caproni, two parasites of Biomphalaria glabrata  

Microsoft Academic Search

Schistosoma mansoni and Echinostoma caproni are two trematode species that use different strategies (mimicry and immunosuppression, respectively) to interfere with the snail innate immune system. Parasites excretory–secretory (ES) products have been shown to play a key role in these host–parasite immune interactions. However, they remain largely uncharacterized in larval trematodes. We developed a global proteomic approach to characterize the ES

François Guillou; Emmanuel Roger; Yves Moné; Anne Rognon; Christoph Grunau; André Théron; Guillaume Mitta; Christine Coustau; Benjamin E. F. Gourbal

2007-01-01

169

Snails, stable iostopes, and southwestern desert paleoclimates  

SciTech Connect

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

Sharpe, S.E. [Univ. and Community College System of Nevada, Reno, NV (United States); Whelan, J.F.; Forester, R.M.; Burdett, J.

1995-09-01

170

Dragonfly predators influence biomass and density of pond snails  

Microsoft Academic Search

Studies in lakes show that fish and crayfish predators play an important role in determining the abundance of freshwater snails.\\u000a In contrast, there are few studies of snails and their predators in shallow ponds and marshes. Ponds often lack fish and crayfish\\u000a but have abundant insect populations. Here we present the results of field surveys, laboratory foraging trials, and an

Andrew M. Turner; Michael F. Chislock

2007-01-01

171

Sequestration of lichen compounds by three species of terrestrial snails  

Microsoft Academic Search

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

Sonja Hesbacher; Bruno Baur; Anette Baur; Peter Proksch

1995-01-01

172

Respiration rates and population metabolism of woodland snails  

Microsoft Academic Search

Experiments were done to measure the respiration rates of twenty species of terrestrial snail. Acclimatization phenomena were sought in two species, Discus rotundatus and Hygromia striolata, but not detected. The Q10s between 5 and 15° C for the twenty species varied between 1.20 and 4.27, with a mean Q10 of 2.21. Q10 was higher in larger snail species. There was

C. F. Mason; Botanic Gardens

1971-01-01

173

Camouflaged or tanned: plasticity in freshwater snail pigmentation  

PubMed Central

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

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

2013-01-01

174

In vivo studies on inhibition and recovery of B-esterase activities in Biomphalaria glabrata exposed to azinphos-methyl: analysis of enzyme, substrate and tissue dependence.  

PubMed

Cholinesterases and carboxylesterases belong to the group of B-esterases, the serine superfamily of esterases that are inhibited by organophosphorus compounds. It is now generally accepted that before using the B-esterases as biomarkers of exposure to organophosphorus and carbamates in a given species, the biochemical characteristics of these enzymes should be carefully studied. In this study, the enzyme/s and the tissue/s to be selected as sensitive biomarkers of organophosphorus exposition in the freshwater gastropod Biomphalaria glabrata were investigated. Firstly, the substrate dependence of cholinesterase and carboxylesterase activities in whole organism soft tissue and in different tissues of the snail (head-foot, pulmonary region, digestive gland, and gonads) was analyzed. Measurements of cholinesterase activity were performed using three substrates: acetylthiocholine (AcSCh), propionylthiocholine (PrSCh), and butyrylthiocholine (BuSCh). Carboxylesterase activity was determined using four different substrates: 1-naphthyl acetate (1-NA), 2-naphthyl acetate (2-NA), p-nitrophenyl acetate (p-NPA), and p-nitrophenyl butyrate (p-NPB). Regardless of the tissue analyzed, the highest specific activity was obtained when using AcSCh, followed by PrSCh. Cholinesterase activity measured with BuSCh was very low in all cases. On the other hand, the highest cholinesterase activity was measured in head-foot and in pulmonary region, representing in the case of AcSCh hydrolysis 196% and 180% of the activity measured in whole organism soft tissue, respectively. In contrast, AcSCh hydrolysis in digestive gland and gonads was 28% and 50% of that measured in whole organism soft tissue. Regarding carboxylesterase activity, although all tissues hydrolyzed the four substrates assayed, substrate preferences varied among tissues. In particular, digestive glands showed higher carboxylesterase activity than the other tissues (299%, 359% and 137% of whole organism soft tissue activity) when measured with 1-NA, 2-NA and p-NPA as substrates, respectively. In contrast, with p-NPB as substrate, the highest carboxylesterase activity was observed in pulmonary region. Exposure of the snails for 48 h to azinphos-methyl concentrations in the range of 0.05-2.5 mg L?¹ resulted in different degrees of inhibition of cholinesterase and carboxylesterase activities, depending on the enzyme, pesticide concentration, the substrate, and the tissue analyzed. In general, carboxylesterase activity measured with p-NPA and p-NPB was much more sensitive to azinphos-methyl inhibition than cholinesterase activity. The results also showed that while B-esterase activities in whole organism soft tissue and pulmonary region recovered completely within 14 days, carboxylesterase activity in digestive glands remained highly inhibited. On the whole, the results of the present study emphasize how important it is to characterize and measure cholinesterase and carboxylesterase activities jointly to make a proper assessment of the impact of organophosphorus pesticides in non-target species. PMID:22360939

Kristoff, Gisela; Barrionuevo, Daniela Chiny; Cacciatore, Luis C; Guerrero, Noemí R Verrengia; Cochón, Adriana C

2012-05-15

175

Vineyard snail allergy possibly induced by sensitization to house-dust mite (Dermatophagoides pteronyssinus).  

PubMed

A female patient experienced a severe allergic reaction after consumption of vineyard snails. The patient proved to be sensitized to house-dust mite (HDM) and demonstrated a positive skin test and specific IgE to snail (Eobania vermiculata, Lofarma). The snail RAST was > 80% inhibited by HDM, whereas the mite RAST was < 10% inhibited by snail extract. This is possibly another example of food allergy related to primary sensitization by an aeroallergen. PMID:7573833

De Maat-Bleeker, F; Akkerdaas, J H; van Ree, R; Aalberse, R C

1995-05-01

176

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

Microsoft Academic Search

The present study characterized copper (Cu) uptake and depuration by juvenile and adult Florida apple snails (Pomacea paludosa) from water, soil, and diet. During a 28-day uptake period, juvenile apple snails were exposed to aqueous Cu and adult apple\\u000a snails were exposed to Cu-contaminated soil, water, and food. In the follow-up 14-day depuration period, both juvenile and\\u000a adult apple snails

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

2008-01-01

177

The Neogastropoda: Evolutionary Innovations of Predatory Marine Snails with Remarkable Pharmacological Potential  

Microsoft Academic Search

\\u000a The Neogastropoda include many familiar molluscs, such as cone snails (Conidae), purple dye snails (Muricidae), mud snails\\u000a (Nassariidae), olive snails (Olividae), oyster drills (Muricidae), tulip shells (Fasciolariidae), and whelks (Buccinidae).\\u000a Due to their amazing predatory specializations, neogastropods are often dominant members of the benthic community at the top\\u000a of the food chain. In a dazzling display that ranges from boring

Maria Vittoria Modica; Mandë Holford

178

Implication of Snail in Metabolic Stress-Induced Necrosis  

PubMed Central

Background 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. Methodology/Principal Findings 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. Conclusions/Significance Taken together, our findings demonstrate that Snail is implicated in metabolic stress-induced necrosis, providing a new function for Snail in tumor progression. PMID:21448462

Ju, Min Kyung; Moon, Ji Young; Park, Hye Gyeong; Yoo, Mi-Ae; Choi, Byung Tae; Yook, Jong In; Lim, Sung-Chul; Han, Song Iy; Kang, Ho Sung

2011-01-01

179

The effects of water availability on the life history of the desert snail, Trochoidea seetzeni  

Microsoft Academic Search

Summary In the Negev desert of Israel, the pulmonate land snailTrochoidea seetzeni is active, grows and reproduces in the month following the torrential winter rains. Thereafter, these snails estivate until the following year's rains. By experimental supplementation of water in the field, we examined the ability of these snails to alter their life histories. Specifically, we measured changes in feeding

David Ward; Robert Slotow

1992-01-01

180

Predation and the distribution and abundance of a pulmonate pond snail  

Microsoft Academic Search

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

Kenneth M. Brown; Dennis R. DeVries

1985-01-01

181

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

PubMed Central

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. PMID:15841274

2005-01-01

182

Effects of azinphos-methyl exposure on enzymatic and non-enzymatic antioxidant defenses in Biomphalaria glabrata and Lumbriculus variegatus  

Microsoft Academic Search

Azinphos-methyl is an organophosphate insecticide used for pest control on a number of food crops in many parts of the world. The oligochaete Lumbriculus variegatus and pigmented and non-pigmented specimens of the gastropod Biomphalaria glabrata are freshwater invertebrates that have been recommended for contamination studies. Recently, it has been shown that L. variegatus worms exhibit a higher cholinesterase (ChE) activity

Gisela Kristoff; Noemí R. Verrengia Guerrero; Adriana C. Cochón

2008-01-01

183

MTA3 regulates CGB5 and Snail genes in trophoblast  

SciTech Connect

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

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

2013-04-19

184

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

PubMed

Euglandina rosea, a predatory land snail, tracks prey and mates by following slime trails. Euglandina follow slime trails more than 80% of the time, following trails of their own species, but not those of prey snails, in the direction that they were laid. The attractive elements of prey slime are small, water-soluble compounds detected by specialized lip extensions. Although olfaction plays no role in trail following, strong odors disrupt tracking. Inhibition of nitric oxide synthase also disrupts slime trail following, suggesting a role for nitric oxide in neural processing of slime trail stimuli. Euglandina can be conditioned to follow novel trails of glutamate or arginine paired with feeding on prey snails. These experiments demonstrate that slime-trail tracking in Euglandina is a robust, easily measured behavior that makes a good model system for studying sensory processing and learning in a novel modality. PMID:14570557

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

2003-10-01

185

Hitchhiking behaviour in the obligatory upstream migration of amphidromous snails  

PubMed Central

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

Kano, Yasunori

2009-01-01

186

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

Technology Transfer Automated Retrieval System (TEKTRAN)

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

187

Influence of snail feces and mucus on oviposition and larval behavior ofPherbellia cinerella (Diptera: Sciomyzidae).  

PubMed

Larvae of the sciomyzid flyPherbellia cinerella are voracious predators of terrestrial helicid snails. Eggs are deposited in areas where snails occur and larvae hunt actively for their prey. Snail feces and mucus were tested to determine if they had any kairomone or stimulatory effects onP. cinerella. Adult flies oviposited more frequently on substrates containing fresh snail feces than on substrates containing snail mucus or water (control). However, mucus and feces both stimulated increased search behaviour in first instar larvae. These results are discussed in relation to snail biology, and the potential for augmentation of these flies in areas affected by pest snails. PMID:24227402

Coupland, J B

1996-02-01

188

Nuclear ubiquitination by FBXL5 modulates Snail1 DNA binding and stability  

PubMed Central

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

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

2014-01-01

189

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

PubMed

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

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

2008-06-01

190

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

PubMed

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 knowledge gap in O. viverrini disease ecology and highlights the potential effect of anthropogenic irrigation practices on B.s. goniomphalos snail ecology. PMID:24561073

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

2015-01-01

191

Survey of Pulmonate Snails of Central Minnesota. I. Lymnaeidae  

Microsoft Academic Search

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

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

1992-01-01

192

Reproductive anomalies in stenoglossan snails related to pollution from marinas.  

PubMed

Over 3090 snails of the dioecious intertidal species Nassarius obsoletus Say were collected from a total of 71 localities. Their reproductive anatomy was examined for a superimposition of male characteristics on to the normal female anatomy, an abnormality called 'imposex'. Imposex was rated numerically in terms of the fraction of the population affected and the intensity of expression in bearer snails. An initial survey of 22 localities in Fairfield and Westport, Connecticut, led to the hypothesis that imposex was related to a substance arising from marinas. This was tested at nine pairs of marina and control localities in Long Island Sound, as well as six pairs along a transect ranging from Rhode Island to Georgia. Imposex scores were significantly higher at the marina locality in every pair. Further confirmation was found in a detailed survey of the estuarine harbor at Southport, Connecticut, which showed that adjacent populations could differ in the amount of imposex to the extent that both the snails and the waters they lived in remained separated by natural or man-made barriers. Imposex has been found in populations of N. obsoletus ranging from Damariscotta, Maine, to Savannah, Georgia, and it has been reported from San Francisco Bay, California. Similar anatomical abnormalities have been reported in at least 27 other species of taenioglossan and stenoglossan snails, extending the range to the Atlantic and Mediterranean coast of Europe and the British Isles. Concern is raised regarding the possible existence of another global pollutant with novel effects on marina biota. PMID:7185869

Smith, B S

1981-02-01

193

The snail superfamily of zinc-finger transcription factors  

Microsoft Academic Search

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

M. Angela Nieto

2002-01-01

194

Sequestration of lichen compounds by three species of terrestrial snails.  

PubMed

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

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

1995-02-01

195

Land Snail Ecology and Biogeography of Eastern Maine  

E-print Network

to the state fauna (Euconulus alderi, Punctum n.sp., Vertigo cristata, Vertigo malleata, Vertigo morseiLand Snail Ecology and Biogeography of Eastern Maine Vertigo bollesiana Vertigo nylanderi Vertigo in the state (Nesovitrea binneyana, Planogyra asteriscus, Striatura ferrea, Striatura milium, Vertigo

Nekola, Jeffrey C.

196

Snail Shells in a Practical Application of Statistical Procedures  

ERIC Educational Resources Information Center

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

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

2007-01-01

197

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

PubMed

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

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

2014-09-01

198

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

PubMed Central

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

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

2014-01-01

199

Small angle x-ray scattering of the hemoglobin from Biomphalaria glabrata.  

PubMed

The hemoglobin from Biomphalaria glabrata is an extracellular respiratory protein of high molecular mass composed by subunits of 360 kDa, each one containing two 180 kDa chains linked by disulfide bridges. In this work, small angle x-ray scattering (SAXS) measurements were performed with the hemoglobin at pH 5.0 and 7.5. Radii of gyration of 98.6 +/- 0.5 and 101.8 +/- 0.2 A and maximum diameters of 300 +/- 10 and 305 +/- 10 A, respectively, were obtained from Guinier plot extrapolation and analytical curve fitting. The pair distance distribution functions p(r) corresponded to globular particles with a somewhat anisotropic shape for both preparations. Computer analysis of the low angle part of the scattering curve led to the determination of the low resolution envelope of the protein, revealing a P(222) symmetry. Shape reconstruction from ab initio calculations using the complete scattering curve furnished a compact prolate three-dimensional (3D) bead model for the protein. Hydrodynamic parameters were obtained from experiments and theoretical calculations using the 3D model. The results of the structural and biochemical studies reported herein indicate that the multisubunit structure of this hemoglobin is compatible with a tetrameric arrangement. PMID:12879493

Arndt, Márcio H L; de Oliveira, Cristiano L P; Régis, Wiliam C B; Torriani, Iris L; Santoro, Marcelo M

2003-08-01

200

Snail2 controls mesodermal BMP/Wnt induction of neural crest  

PubMed Central

The neural crest is an induced tissue that is unique to vertebrates. In the clawed frog Xenopus laevis, neural crest induction depends on signals secreted from the prospective dorsolateral mesodermal zone during gastrulation. The transcription factors Snail2 (Slug), Snail1 and Twist1 are expressed in this region. It is known that Snail2 and Twist1 are required for both mesoderm formation and neural crest induction. Using targeted blastomere injection, morpholino-based loss of function and explant studies, we show that: (1) Snail1 is also required for mesoderm and neural crest formation; (2) loss of snail1, snail2 or twist1 function in the C2/C3 lineage of 32-cell embryos blocks mesoderm formation, but neural crest is lost only in the case of snail2 loss of function; (3) snail2 mutant loss of neural crest involves mesoderm-derived secreted factors and can be rescued synergistically by bmp4 and wnt8 RNAs; and (4) loss of snail2 activity leads to changes in the RNA levels of a number of BMP and Wnt agonists and antagonists. Taken together, these results identify Snail2 as a key regulator of the signals involved in mesodermal induction of neural crest. PMID:21715424

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

2011-01-01

201

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

PubMed Central

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

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

2014-01-01

202

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

PubMed

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

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

2011-11-01

203

Metabolic acceleration in the pond snail Lymnaea stagnalis?  

NASA Astrophysics Data System (ADS)

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

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

2014-11-01

204

Snail and Sonic Hedgehog activation in neuroendocrine tumors of the ileum  

Microsoft Academic Search

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

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

2007-01-01

205

Use of Bayluscide (Bayer 73) for Snail Control in Fish Ponds  

Microsoft Academic Search

Bayluscide applied to ponds on two commercial fish farms at five rates (from L1 to 13.5 kilogram per surface hectare) effectively controlled aquatic snails. Laboratory toxicity tests confirmed susceptibility of three endemic species of aquatic snail—Melanoides tuberculatus, Physella hendersoni, and Planorbella duryi—to Bayluscide. Observed 24-h concentrations lethal to 50% of snails (LC50) ranged from 0.062 to 0.085 mg\\/L, and 24-h

Ruth Francis-Floyd; James Gildea; Peggy Reed; Ruthellen Klinger

1997-01-01

206

Structure of mega-hemocyanin reveals protein origami in snails.  

PubMed

Mega-hemocyanin is a 13.5 MDa oxygen transporter found in the hemolymph of some snails. Similar to typical gastropod hemocyanins, it is composed of 400 kDa building blocks but has additional 550 kDa subunits. Together, they form a large, completely filled cylinder. The structural basis for this highly complex protein packing is not known so far. Here, we report the electron cryomicroscopy (cryo-EM) structure of mega-hemocyanin complexes from two different snail species. The structures reveal that mega-hemocyanin is composed of flexible building blocks that differ in their conformation, but not in their primary structure. Like a protein origami, these flexible blocks are optimally packed, implementing different local symmetries and pseudosymmetries. A comparison between the two structures suggests a surprisingly simple evolutionary mechanism leading to these large oxygen transporters. PMID:25482543

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

2015-01-01

207

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

NASA Astrophysics Data System (ADS)

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

Hodgson, Alan N.; Dickens, John

2012-08-01

208

Analysis of Snail1 function and regulation by Twist1 in palatal fusion  

PubMed Central

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

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

2013-01-01

209

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

PubMed Central

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

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

2014-01-01

210

The Helix aspersa (Brown Garden Snail) Allergen Repertoire  

Microsoft Academic Search

Background: Ingestion of snails can induce strong asthmatic or anaphylactic responses, mainly in house-dust-mite-sensitized patients. The aim of this study was to identify the Helix aspersa (Hel a), Theba pisana (The p) and Otala lactea (Ota l) allergens and the extent of their cross-reactivity with the Dermatophagoides pteronyssinus (Der p) mite. Patients and Methods: In 60 atopicpatients, skin prick tests

Luís Miguel Lourenço Martins; Gabriel Peltre; Carlos José Fialho da Costa Faro; Euclides Manuel Vieira Pires; Filipe Fernando da Cruz Inácio

2005-01-01

211

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

PubMed

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

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

2013-12-01

212

Embryonic Toxin Expression in the Cone Snail Conus victoriae  

PubMed Central

Predatory marine cone snails (genus Conus) utilize complex venoms mainly composed of small peptide toxins that target voltage- and ligand-gated ion channels in their prey. Although the venoms of a number of cone snail species have been intensively profiled and functionally characterized, nothing is known about the initiation of venom expression at an early developmental stage. Here, we report on the expression of venom mRNA in embryos of Conus victoriae and the identification of novel ?- and O-conotoxin sequences. Embryonic toxin mRNA expression is initiated well before differentiation of the venom gland, the organ of venom biosynthesis. Structural and functional studies revealed that the embryonic ?-conotoxins exhibit the same basic three-dimensional structure as the most abundant adult toxin but significantly differ in their neurological targets. Based on these findings, we postulate that the venom repertoire of cone snails undergoes ontogenetic changes most likely reflecting differences in the biotic interactions of these animals with their prey, predators, or competitors. To our knowledge, this is the first study to show toxin mRNA transcripts in embryos, a finding that extends our understanding of the early onset of venom expression in animals and may suggest alternative functions of peptide toxins during development. PMID:21504902

Safavi-Hemami, Helena; Siero, William A.; Kuang, Zhihe; Williamson, Nicholas A.; Karas, John A.; Page, Louise R.; MacMillan, David; Callaghan, Brid; Kompella, Shiva Nag; Adams, David J.; Norton, Raymond S.; Purcell, Anthony W.

2011-01-01

213

Effect of amphotericin B on the infection success of Schistosoma mansoni in Biomphalaria glabrata.  

PubMed

In the present study, we examined the effect of amphotericin B on larval stages (miracidia and primary sporocyst) of the helminth Schistosoma mansoni, the causative agent of human schistosomiasis. Amphotericin B (AmB) is a polyene macrolide that disturbs the function of the cell membrane; it is widely used as prophylactic antimycotic agent in in vitro culture. We show for the first time that S. mansoni miracidia infectivity is considerably reduced after AmB treatment. Moreover we demonstrate that AmB does not affect the development, growth, viability, and behavior of miracidia and primary sporocysts. Our data indicate that AmB effects on S. mansoni sporocyst prevalence are linked to the oxidative properties of AmB. These may alter the capacity of sporocysts to respond to the oxidative stress generated by the snail immune defence system. PMID:20067790

Moné, Yves; Mitta, Guillaume; Duval, David; Gourbal, Benjamin E F

2010-06-01

214

Freshwater snails and schistosomiasis mansoni in the State of Rio de Janeiro, Brazil: I-- Metropolitan mesoregion.  

PubMed

In order to elaborate a planorbid chart of the State of Rio de Janeiro a survey of freshwater gastropods in the Metropolitan Mesoregion of this State was performed and revealed the occurrence of 20 species: Antillorbis nordestensis (Lucena, 1954); Biomphalaria glabrata (Say, 1818); Biomphalaria schrammi (Crosse, 1864); Biomphalaria straminea (Dunker, 1848); Biomphalaria tenagophila (Orbigny, 1835); Burnupia sp.; Drepanotrema anatinum (Orbigny, 1835); Drepanotrema cimex (Moricand, 1839); Drepanotrema lucidum (Pfeiffer, 1839); Ferrissia sp.; Gundlachia ticaga (Marcus & Marcus, 1962); Heleobia davisi Silva & Thomé, 1985; Lymnaea columella Say, 1817; Melanoides tuberculatus (Müller, 1774); Physa cubensis Pfeiffer, 1839; Physa marmorata Guilding, 1828; Pomacea sp.; Pomacea canaliculata (Lamarck, 1822); Pomacea lineata (Spix, 1827) and Pomacea sordida (Swainson, 1823). Among the planorbid species B. tenagophila was the most frequent, occurring in all municipalities surveyed. The present study extends the distribution of B. straminea in the State of Rio de Janeiro and reports new records for A. nordestensis, B. schrammi, G. ticaga, H. davisi and the genera Burnupia and Ferrissia. An account about the current transmission areas of schistosomiasis mansoni in this Mesoregion is presented as well. PMID:11586447

Thiengo, S C; Fernandez, M A; Boaventura, M F; Grault, C E; Silva, H F; Mattos, A C; Santos, S B

2001-01-01

215

Plagiorchis elegans (Trematoda) and incompatible snail hosts: implications for snail life history traits and biocontrol of human schistosomiasis.  

PubMed

We examined the effect of Plagiorchis elegans on egg production and survival on Bulinus truncatus and Helisoma trivolvis trivolvis. Both species are incompatible hosts for P. elegans. Helisoma t. trivolvis occurs sympatrically with P. elegans; B. truncatus does not. Overall, P. elegans had no effect on survivorship or egg production in H. t. trivolvis or on the survivorship of B. truncatus. Its effect on egg production in B. truncatus was transitory; egg production was reduced by 50% for 5 wk following exposure but returned to normal thereafter. Neither egg production nor survivorship was affected in adult H. t. trivolvis. Egg production ceased at 14 wk post-exposure (PE), but resumed when the snails were paired. Young H. t. trivolvis also produced eggs after exposure, but later than the adults and only after they had been paired with another snail. This suggests that a need for periodic cross-fertilization in H. t. trivolvis rather than the effect of the parasite is responsible for the cessation of egg production in this species. Survivorship in young H. t. trivolvis was significantly higher in exposed snails between wk 7 to 10 PE than in controls. PMID:19566345

Daoust, Simon P; Mader, Brian J; McLaughlin, J Daniel; Rau, Manfred E

2009-12-01

216

Fresh water malacologic fauna in Dakahlia Governorate.  

PubMed

Ten snail species representing the snail fauna in Dakahlia were identified as P. acuta, B. unicolor, L. carinatus, Cleopatra species, B. alexandrina, M. tuberculatus, H. duryi, B. truncatus, N. nilotica and L. caillaudi. The density of snail population has had a major peak at July and August while a minor peak was found at the winter closure period during the winter months. PMID:2230321

el-Shazly, A M; Handoussa, A E; Romia, S A; el-Ganaini, G A; Youssef, M E; Abou-Zakham, A A; Hegazi, M M

1990-12-01

217

Survival of the Faucet Snail after Chemical Disinfection, pH extremes, and Heated Water Bath Treatments  

Microsoft Academic Search

The faucet snail Bithynia tentaculata, a nonindigenous aquatic snail from Eurasia, was introduced into Lake Michigan in 1871 and has spread to the mid-Atlantic states, the Great Lakes region, Montana, and most recently, the Mississippi River. The faucet snail serves as intermediate host for several trematodes that have caused large-scale mortality among water birds, primarily in the Great Lakes region

Andrew J. Mitchell; Rebecca A. Cole

2008-01-01

218

Temperature Tolerance of Red-Rim Melania Melanoides tuberculatus, an Exotic Aquatic Snail Established in the United States  

Microsoft Academic Search

The red-rim melania Melanoides tuberculatus (family Thiaridae), a tropical, nonindigenous aquatic snail, has become established and is spreading in the United States. Concerns associated with the spread of this snail include its potential to displace native snail populations and to transmit trematodes. Of particular concern is the gill trematode Centrocestus formosanus now found in U.S. commercial and wild fish stocks.

Andrew J. Mitchell; Thomas M. Brandt

2005-01-01

219

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

ERIC Educational Resources Information Center

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

Stewart, Timothy W.

2007-01-01

220

The influence of TCS on the growth and behavior of the freshwater snail, Physa acuta  

Microsoft Academic Search

Triclosan (TCS) is among the top 10 most persistent contaminants found in U.S. rivers, streams, lakes, and aquifers. Although TCS has not been found to be hazardous to humans, it can be toxic to aquatic environments and animals. The effects of TCS on growth rates and the locomotive behavior of the freshwater snail, Physa acuta, were studied by exposing snails

Jenell Brown; Melody J. Bernot; Randall J. Bernot

2012-01-01

221

The detection of snail host habitats in liver fluke infected farms by use of plant indicators  

Microsoft Academic Search

Field investigations in 361 liver fluke infected cattle- or sheep-breeding farms on acid soil were carried out during thirty years in March and April to record indicator plants in relation to the category of site colonized by the intermediate host of liver fluke, the snail Galba truncatula. Seven types of snail zones and six species of indicator plants were recorded

Daniel Rondelaud; Philippe Hourdin; Philippe Vignoles; Gilles Dreyfuss; Jacques Cabaret

2011-01-01

222

Effect of light intensity on Opisthorchis viverrini cercarial shedding levels from Bithynia snails — A preliminary study  

Microsoft Academic Search

Opisthorchis viverrini requires Bithynia snails as the first intermediate host and cyprinid fish as the second intermediate host. Very low natural infection rates have been reported in Bithynia snails, but very high rates have been found in cyprinid fish in the same endemic region. This study investigated the effect of light intensity, the most important stimulus, on the quantity of

Sasithorn Kaewkes; Wanlop Kaewkes; Thidarut Boonmars; Banchob Sripa

223

A molecular phylogeography approach to biological invasions of the New World by parthenogenetic Thiarid snails  

Microsoft Academic Search

The parthenogenetic snail Melanoides tuberculata , present in tropical fresh waters of most of the Old World before 1950, has now invaded the Neotropical area. The phylogeography of this snail was studied to evaluate the pathways and number of such invasions. Because of parthenogenetic reproduction, individuals are structured into genetical clones. Within populations from both the original and invaded areas,

B. FACON; J.-P. POINTIER; M. GLAUBRECHT; C. POUX; P. JARNE; P. DAVID

2003-01-01

224

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

Technology Transfer Automated Retrieval System (TEKTRAN)

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

225

Effects of desiccation on two life stages of an invasive snail and its native cohabitant  

Microsoft Academic Search

Invasive species are of critical concern as they have the potential to rapidly alter biotic systems around the globe. The\\u000a upper Mississippi River (UMR) system has been recently invaded by the aquatic snail, Bithynia tentaculata, which spread from the Great Lakes region. In addition to potentially impacting native aquatic snails, B. tentaculata also carries three parasites which kill thousands of

Allison M. Wood; Cody R. Haro; Roger J. Haro; Gregory J. Sandland

226

Larval stages of digenetic trematodes in Melanopsis praemorsa snails from freshwater bodies in Palestine  

PubMed Central

Objective To detect the species of larval trematodes (cercariae) in Melanopsis praemorsa snails from 5 different fresh water bodies in Palestine. Methods A total of 1 880 Melanopsis praemorsa snails were collected from different fresh water bodies in Palestine from October, 2008 to November, 2010. Cercariae in Melanopsis praemorsa snails were obtained by lighting and crushing methods. The behavior of cercariae was observed using a dissecting microscope. Results Three different species of larval trematodes were identified from Melanopsis praemorsa snails collected only from Al-Bathan fresh water body, while snails from other water bodies were not infected. These species were microcercous cercaria, xiphidiocercaria and brevifurcate lophocercous cercaria. These cercariae called Cercaria melanopsi palestinia I, Cercaria melanopsi palestinia II and Cercaria melanopsi palestinia III have not been described before from this snail in Palestine. The infection rate of Melanopsis praemorsa collected from Al-Bathan fresh water body was 5.7%, while the overall infection rate of snails collected from all fresh water bodies was 4.3%. Details are presented on the morphology and behavior of the cercariae as well as their development within the snail. Conclusions These results have been recorded for the first time and these cercariae may be of medical and veterinary importance. PMID:23569759

Bdir, Sami; Adwan, Ghaleb

2011-01-01

227

Guanine and Inosine Nucleotides, Nucleosides and Oxypurines in Snail Muscles as Potential Biomarkers of Fluoride Toxicity  

Microsoft Academic Search

The aim of the present study was to determine the toxicity of fluorides on energy metabolism in muscles of the Helix aspersa maxima snail. Qualitative and quantitative analysis of purine compounds was performed in slices of foot from mature snails with high-performance liquid chromatography. Fluoride concentrations were measured using an ion-selective electrode and gas chromatography. The results show that exposure

Monika E. Ra?; Krzysztof Safranow; Barbara Do??gowska; Zygmunt Machoy

2007-01-01

228

Acetylation and hydroxylation of sulphatroxazole in the snail Cepaea hortensis and the slug Arion rufus  

Microsoft Academic Search

The snail Cepaea hortensis can acetylate and hydroxylate sulphatroxazole via a pathway similar to that in man. The principal metabolic pathways, in order of decreasing rate, are hydroxylation, glucuronidation and acetylation. The slug Anion rufus also can acetylate and hydroxylate sulphatroxazole, although, in contrast to the snail, is rate of acetylation is higher than that of hydroxylation.

T. B. Vree; M. L. Vree; J. F. M. Nouws

1987-01-01

229

Acetylation and hydroxylation of sulphatroxazole in the snail Cepaea hortensis and the slug Arion rufus.  

PubMed

The snail Cepaea hortensis can acetylate and hydroxylate sulphatroxazole via a pathway similar to that in man. The principal metabolic pathways, in order of decreasing rate, are hydroxylation, glucuronidation and acetylation. The slug Arion rufus also can acetylate and hydroxylate sulphatroxazole, although, in contrast to the snail, is rate of acetylation is higher than that of hydroxylation. PMID:3564322

Vree, T B; Vree, M L; Nouws, J F

1987-01-01

230

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

SciTech Connect

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

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

2013-12-10

231

Predator-induced life-history shifts in a freshwater snail.  

PubMed

The snail Physella virgata virgata, a widely distributed freshwater pulmonate, was observed to change its life-history characteristics in the presence of the crayfish Orconectes virilis in spring-fed Oklahoma streams. These changes were apparently initiated by a water-borne cue released when crayfish fed on conspecific snails. In the presence of the cue, snails exhibited rapid growth rates and little reproduction until they reached a size of about 10 mm after 8 months. In the absence of the cue, snails typically grew to about 4 mm (3.5 months) and then began reproduction. The chemically inducible shift indicates that the life histories of these snails are phenotypically plastic. By increasing the variance associated with size and age of maturity, prey may increase the likelihood of coexisting with seasonal predators. PMID:17776452

Crowl, T A; Covich, A P

1990-02-23

232

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

PubMed

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

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

2009-03-18

233

Transcription factor Snail regulates TNF-?-mediated synovial fibroblast activation in rheumatoid joint.  

PubMed

Objective. Transcription factor Snail is involved in various biological functions. We hypothesized that this molecule regulates TNF-?-mediated synovial fibroblasts (SF) activation in rheumatoid joint, and examined its roles in expression of Cadherin-11 (Cad-11) and myofibroblast markers, invasive ability and IL-6 production. Methods. Synovium was obtained from rheumatoid arthritis (RA) patients and collagen-induced arthritis (CIA) rats. SF were treated with TNF-? or a Wnt signaling inducer, and CIA joints were injected with a TNF-? antagonist. Modulation of Snail expression in SF and joints was performed by lentiviral vector-mediated transfer of cDNA or short hairpin RNA. Results. Snail and Cad-11 were expressed at higher levels in synovium and SF from RA patients and CIA rats. TNF-? stimulation or Wnt signaling activation upregulated the expression levels of Snail, Cad-11 and ?-smooth muscle actin (SMA) in SF, and anti-TNF-? therapy down-regulated their expression levels in CIA joints. While Snail-overexpressed SF transfectants had increased expression levels of Cad-11 and ?-SMA and enhanced TNF-?-mediated invasive capacity and IL-6 production, Snail-knockdowned CIASF transfectants had decreased expression levels and the opposite effect on these functions. Snail-overexpressed normal joints had hyperplastic synovium with increased expression levels of Cad-11, ?-SMA and IL-6. Silencing Snail expression ameliorated arthritis with reduced Cad-11 expression and extracellular matrix deposition levels in CIA joints, whereas overexpression of Snail exacerbated arthritis with increased expression and deposition levels. Conclusion. Our results demonstrate that Snail regulates TNF-?-mediated SF activation in rheumatoid joint, and these findings might contribute to the pharmacological development of therapeutics targeting SF in RA patients. © 2014 American College of Rheumatology. PMID:25303734

Chen, Shih-Yao; Shiau, Ai-Li; Li, Yuan-Tsung; Lin, Chi-Chen; Jou, I-Ming; Liu, Ming-Fei; Wu, Chao-Liang; Wang, Chrong-Reen

2014-10-01

234

Why are there few algae on snail shells? The effects of grazing, nutrients and shell chemistry on the algae on shells of Helisoma trivolvis  

Microsoft Academic Search

SUMMARY 1. Freshwater snails often lack visible growths of algae on their shells. We tested three possible mechanisms that may account for this (grazing, snail-derived nutrients and chemical defences), using the ramshorn snail Helisoma trivolvis. 2. The experiments were carried out in floating plastic enclosures in a pond and comprised seven treatments. Grazing treatments were: a lone snail (ungrazed, as

LINDSEY L. ABBOTT; ELIZABETH A. BERGEY

2007-01-01

235

Population studies on Oncomelania quadrasi, the snail intermediate host of Schistosoma japonicum, in the Philippines. 5. Quantitative analysis on successful snail control by land reclamation.  

PubMed

For the control of Oncomelania quadrasi, environmental modifications, i.e., clearing of vegetation, leveling of swampy depression and draining of stagnant water by channeling and excavation were carried out at 3 areas in Leyte, Philippines from 1974 to 1977. The change of snail population resulted in the land reclamation was evaluated by the methods previously developed by the population studies on this snail. As a result of statistical analysis based on y = log(x + 0.01) transformation and the antilogarithmic mean density A-y = (antilog -y) -0.01, the reduction of snail population was observed at 13 out of 18 sites studied at 3 project areas and the significant reduction was statistically confirmed at 9 sites of them. Particularly at Dagami area, which was a wide and heavily snail-infested land adjacent to Dagami Poblacion, the reduction rate of snail density reached 87.7% to 99.2% and some wet depressions have been converted into good rice fields with little snail infestation at the last survey. PMID:3090317

Makiya, K; Tanaka, H; Bañez, E; Blas, B L; Santos, A T

1986-04-01

236

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

PubMed

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

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

2010-01-01

237

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

SciTech Connect

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

Russell, L.K. (Northrop Services Inc., Corvallis, OR); DeHaven, J.I.; Botts, R.P.

1981-05-01

238

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

PubMed Central

Invertebrates were long thought to possess only a simple, effective and hence non-adaptive defence system against microbial and parasitic attacks. However, recent studies have shown that invertebrate immunity also relies on immune receptors that diversify (e.g. in echinoderms, insects and mollusks (Biomphalaria glabrata)). Apparently, individual or population-based polymorphism-generating mechanisms exists that permit the survival of invertebrate species exposed to parasites. Consequently, the generally accepted arms race hypothesis predicts that molecular diversity and polymorphism also exist in parasites of invertebrates. We investigated the diversity and polymorphism of parasite molecules (Schistosoma mansoni Polymorphic Mucins, SmPoMucs) that are key factors for the compatibility of schistosomes interacting with their host, the mollusc Biomphalaria glabrata. We have elucidated the complex cascade of mechanisms acting both at the genomic level and during expression that confer polymorphism to SmPoMuc. We show that SmPoMuc is coded by a multi-gene family whose members frequently recombine. We show that these genes are transcribed in an individual-specific manner, and that for each gene, multiple splice variants exist. Finally, we reveal the impact of this polymorphism on the SmPoMuc glycosylation status. Our data support the view that S. mansoni has evolved a complex hierarchical system that efficiently generates a high degree of polymorphism—a “controlled chaos”—based on a relatively low number of genes. This contrasts with protozoan parasites that generate antigenic variation from large sets of genes such as Trypanosoma cruzi, Trypanosoma brucei and Plasmodium falciparum. Our data support the view that the interaction between parasites and their invertebrate hosts are far more complex than previously thought. While most studies in this matter have focused on invertebrate host diversification, we clearly show that diversifying mechanisms also exist on the parasite side of the interaction. Our findings shed new light on how and why invertebrate immunity develops. PMID:19002242

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

2008-01-01

239

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

PubMed Central

Background 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. Methods 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. Results 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?Snail overexpression, including genes related to metastasis and invasion. Conclusion Snail significantly affects invasiveness/migratory ability of GCs, and may also be used as a predictive biomarker for prognosis or aggressiveness of GCs. PMID:23151184

2012-01-01

240

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

PubMed

The chemokine receptor 7 (CCR7) and Snail signaling have been linked to various types of cancers. The associations between these signalings and the epithelial-mesenchymal transition (EMT) are not clear in gastric cancer. Here, the expression of CCR7 and Snail was detected in gastric cancer by immunohistochemistry and Western blot. Meanwhile, gastric cancer cells were subjected to CCL19, si-control, and si-Snail treatment. Cell cycle, migration, and invasion were also analyzed. The expression patterns of CCR7 and Snail were similar in either gastric cancer tissues or cells. The increased expression of CCR7 was closely associated with the increased Snail expression, which both were closely correlated with metastasis, stage and differentiation, and poor prognosis. The increased p-ERK, p-AKT, Snail, and MMP9 expression and the decreased E-cadherin were confirmed in MGC803 cells in a dose-dependent manner in response to CCL19 treatment. However, the blockade of Snail abrogated the up-regulation of MMP9 and down-regulation of E-cadherin. CCR7-induced ERK and PI3K pathway regulated Snail signaling. Besides si-Snail treatment led to MGC803 cell cycle arrest and affected the migration and invasion. In conclusion, our study suggested that CCR7 promotes Snail expression to induce the EMT, resulting in cell cycle progression, migration, and invasion in gastric cancer. CCR7-Snail pathway provided more potential regimens for cancer therapy. PMID:25572817

Zhang, Jianping; Zhou, Yunzhe; Yang, Yonggang

2015-02-01

241

Snail Regulates Cell-Matrix Adhesion by Regulation of the Expression of Integrins and Basement Membrane Proteins*  

PubMed Central

Snail, a transcriptional repressor of E-cadherin expression, plays a role in the process of epithelial-mesenchymal transition. However, the molecular basis of the role of snail in epithelial-mesenchymal transition has not been fully clarified. Here we show that the expression of snail in epithelial Madin-Darby canine kidney (MDCK) and A431 cells enhances both cell detachment and attachment. Snail did not confer resistance to anoikis induced by loss of contact but instead enhanced cell attachment to extracellular matrices such as fibronectin. This attachment was inhibited by Arg-Gly-Asp (RGD) peptides. Up-regulation of the promoter activity of integrin ?V was observed in snail-expressing MDCK (MDCK/snail) cells. Snail also enhanced MDCK cell migration toward osteopontin that is a ligand for integrin ?V?3. We confirmed the reduction of basement membrane proteins such as laminin (LN) ?3, ?3, and ?2 (laminin-5/LN-5) and of receptors for LN-5 such as integrins ?3, ?6, or ?4 in MDCK/snail or in snail-expressing A431 (A431/snail) cells. Nevertheless, suppression of LN-?3 chain by transient transfection of small interference RNAs resulted in no enhancement of cell detachment. We also found an induction of matrix metalloproteinase-3 in MDCK/snail and A431/snail cells. However, the inhibition of matrix metalloproteinase-3 showed no significant effect on the detachment of MDCK/snail cells. These results suggest that snail enhances cell detachment by multiple mechanism and leads to cell migration and reattachment at a second site, at least in part, by changing the expression of integrins in the cells. PMID:18593711

Haraguchi, Misako; Okubo, Tadashi; Miyashita, Yayoi; Miyamoto, Yasunori; Hayashi, Masao; Crotti, Tania N.; McHugh, Kevin P.; Ozawa, Masayuki

2008-01-01

242

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

PubMed

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

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

2014-01-01

243

Allying with armored snails: the complete genome of gammaproteobacterial endosymbiont  

PubMed Central

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

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

2014-01-01

244

A molecular role for lysyl oxidase-like 2 enzyme in Snail regulation and tumor progression  

PubMed Central

The transcription factor Snail controls epithelial–mesenchymal transitions (EMT) by repressing E-cadherin expression and other epithelial genes. However, the mechanisms involved in the regulation of Snail function are not fully understood. Here we show that lysyl-oxidase-like 2 and 3 (LOXL2 and LOXL3), two members of the lysyl-oxidase gene family, interact and cooperate with Snail to downregulate E-cadherin expression. Snail's lysine residues 98 and 137 are essential for Snail stability, functional cooperation with LOXL2/3 and induction of EMT. Overexpression of LOXL2 or LOXL3 in epithelial cells induces an EMT process, supporting their implication in tumor progression. The biological importance of LOXL2 is further supported by RNA interference of LOXL2 in Snail-expressing metastatic carcinoma cells, which led to a strong decrease of tumor growth associated to increased apoptosis and reduced expression of mesenchymal and invasive/angiogenic markers. Taken together, these results establish a direct link between LOXL2 and Snail in carcinoma progression. PMID:16096638

Peinado, Héctor; del Carmen Iglesias-de la Cruz, Maria; Olmeda, David; Csiszar, Katalin; Fong, Keith S K; Vega, Sonia; Nieto, Maria Angela; Cano, Amparo; Portillo, Francisco

2005-01-01

245

Snail-Mediated Regulation of Reactive Oxygen Species in ARCaP Human Prostate Cancer Cells  

PubMed Central

Reactive oxygen species increases in various diseases including cancer and has been associated with induction of epithelial-mesenchymal transition (EMT), as evidenced by decrease in cell adhesion-associated molecules like E-cadherin, and increase in mesenchymal markers like vimentin. We investigated the molecular mechanisms by which Snail transcription factor, an inducer of EMT, promotes tumor aggressiveness utilizing ARCaP prostate cancer cell line. An EMT model created by Snail overexpression in ARCaP cells was associated with decreased E-cadherin and increased vimentin. Moreover, Snail-expressing cells displayed increased concentration of reactive oxygen species (ROS), specifically, superoxide and hydrogen peroxide, in vitro and in vivo. Real time PCR profiling demonstrated increased expression of oxidative stress-responsive genes, such as aldeyhyde oxidase I, in response to Snail. The ROS scavenger, N-acetyl cysteine partially reversed Snail-mediated EMT after 7 days characterized by increased E-cadherin levels and decreased ERK activity, while treatment with the MEK inhibitor, UO126, resulted in a more marked effect by 3 days, characterized by cells returning back to the epithelial morphology and increased E-cadherin. In conclusion, this study shows for the first time that Snail transcription factor can regulate oxidative stress enzymes and increase ROS-mediated EMT regulated in part by ERK activation. Therefore, Snail may be an attractive molecule for therapeutic targeting to prevent tumor progression in human prostate cancer. PMID:21093414

Barnett, Petrina; Arnold, Rebecca S.; Mezencev, Roman; Chung, Leland W. K.; Zayzafoon, Majd; Odero-Marah, Valerie

2010-01-01

246

Snail intermediate host/Schistosoma haematobium relationships from three transmission sites in Benin (West Africa).  

PubMed

The relationships between three strains of Schistosoma haematobium (Doh, Sô-Tchanhoué and Toho-Todougba; from Benin, West Africa) and their snail hosts were assessed by measurement of several life-history traits, including the infection rate; pre-patent period; cercarial production of each parasite strain; and growth, fecundity and survival of the host snails. Adaptations to its local snail host was found for the Toho-Todougba strain and included a short pre-patent period, a long patent period and production of more cercariae in its local snail host. In contrast, the life-history traits of the Doh and Sô-Tchanhoué strains indicated non-local adaptations, as some sympatric host-parasite combinations were not compatible, the highest infection rates occurred in the allopatric snail Bulinus wrighti, and the duration of cercarial production was short because of the high level of mortality of the snails. Furthermore, snail reproduction ceased following infection by each of the three parasite strains, and the life-history traits were not influenced by the miracidial dose. PMID:23052762

Ibikounlé, Moudachirou; Mouahid, Gabriel; Mintsa Nguema, Rodrigue; Sakiti, Nestor; Massougbodji, Achille; Moné, Hélène

2013-01-01

247

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

PubMed

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

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

2015-01-01

248

Does social facilitation affect responses to natural and anthropogenic stressors in the freshwater snail Planorbella trivolvis?  

PubMed

Social facilitation is the initiation or increase of a trait, such as stressor tolerance, when in the presence of conspecifics, members of the same species. It has been shown to alter the outcome of toxicity experiments in colonial organisms. We evaluated whether social facilitation would impact responses to stressors in the noncolonial New Mexico ramshorn snail (Planorbella trivolvis) by exposing snails to stressors either singly or in groups of three. Social facilitation did not impact snail responses to malathion but did affect responses to predator cues and temperature stress. PMID:21935982

Plautz, Stephanie C; Salice, Christopher J

2011-12-01

249

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

PubMed Central

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

Bartlett, K H; Trust, T J

1976-01-01

250

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

PubMed Central

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

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

2013-01-01

251

High temperature enhances host pathology in a snail trematode system: possible consequences of climate  

E-print Network

of amphibian limb malformations, and its snail intermediate host Planorbella trivolvis. We determined deformities, phenological mismatch, Planorbella trivolvis, Ribeiroia ondatrae, vital rates Introduction is amplified at higher temperatures. 4. The timing of interactions between R. ondatrae and P. trivolvis may

Johnson, Pieter

252

The production of mammalian trematode infective stages by the snail Galba truncatula.  

PubMed

Several experiments on the breeding of trematode-infected Galba truncatula for obtaining and packaging Fasciola hepatica and Paramphistomum daubneyi metacercariae were carried out to determine the more convenient methods to use for commercial production of these infective stages. Compared to the breeding of infected snails in aquaterraria, the use of 14-cm Petri dishes allowed a greater prevalence of snail infection and a higher number of metacercariae. The production of these larvae was still 2.3-3.4 times greater if infected snails were dissected during the patent period. The aspiration of these metacercariae at the extremity of a Pasteur pipette significantly shortens the time necessary for their transfer from Petri dishes to Eppendorf tubes. Using 14-cm Petri dishes, snail dissection and metacercarial aspiration for their transfer strongly reduce the cost price for metacercarial production of the trematodes Fasciola hepatica and Paramphistomum daubneyi. PMID:23182081

Rondelaud, D; Mouzet, R; Vignoles, P; Dreyfuss, G; Cabaret, J

2014-03-01

253

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

PubMed Central

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

Deheyn, Dimitri D.; Wilson, Nerida G.

2011-01-01

254

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

PubMed Central

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

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

2014-01-01

255

Cloning of an olfactory sensory neuron-specific protein in the land snail (Eobania vermiculata).  

PubMed Central

We have isolated a gene encoding for an olfactory sensory neuron (OSN)-specific protein in an invertebrate, the land snail Eobania vermiculata (GenBank accession number AY147909). Using in situ hybridization, we detected expression of its mRNA in the dendrite, cell body and axon of OSNs. By neural tracing, using the lipophilic tracer DiI and in situ hybridization, we have revealed the organization of OSNs and their connections with olfactory glomeruli in the land snail. Sequence and expression pattern analogy of land snail protein with olfactory marker protein (OMP) from vertebrates suggest that the land snail protein is an OMP-like protein. This protein could represent a plesiomorphic character in the evolution of olfactory proteins. PMID:15101416

Mazzatenta, Andrea; Pelosi, Paolo; Cellerino, Alessandro

2004-01-01

256

Stages of oogenesis in the snail, Helix aspersa : cytological, cytochemical and ultrastructural studies  

E-print Network

Stages of oogenesis in the snail, Helix aspersa : cytological, cytochemical and ultrastructural, France. Summary. Oogenesis was studied in adult Helix aspersa using light and electron micros- copy rela- tions between oocytes and follicle cells. Introduction. Oogenesis inside molluscs

Paris-Sud XI, Université de

257

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

PubMed Central

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

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

2012-01-01

258

Evening roosts of the snail kite in Florida  

USGS Publications Warehouse

A total of 36 roost sites of the Snail Kite (Rostrhamus sociabilis) were studied in southern Florida, of which four (11%) were used regularly for 6 or more years. Major roosts were also used as nesting sites. All roosts were in flooded marshes and 33 (91.6%) were in stands of coastal-plain willow. Population increase and the number of roosts were strongly correlated. The number of kites arriving at roosts before sunset was smaller than arriving after sunset (37.8:62.2%), and gray birds (adult and subadult males) generally went to roost earlier than brown birds (all females and immature males). Rites tended to go to roost earlier on cloudy days. Morning departure from roosts was over a much shorter time than arrivals in the afternoon. Ninety-two percent of the kite roosts were also used by other species of birds for roosting, 8 1% of which were eight species of herons.

Sykes, P.W., Jr.

1985-01-01

259

The Epithelial-Mesenchymal Transition Factor SNAIL Paradoxically Enhances Reprogramming  

PubMed Central

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

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

2014-01-01

260

Copper toxicity to the fresh water snail, Lymnaea luteola  

SciTech Connect

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

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

1987-07-01

261

Solar radio-transmitters on snail kites in Florida  

USGS Publications Warehouse

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

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

1989-01-01

262

Feeding and Growth Responses of the Snail Theba pisana to Dietary Metal Exposure  

Microsoft Academic Search

The effects of dietary exposure to copper (Cu), lead (Pb), and zinc (Zn) on feeding activities, growth response, and mortality\\u000a of Theba pisana snails were studied in 5-week feeding tests. Snails were fed on an artificial diet containing the following Cu, Pb, or Zn\\u000a concentrations: 0, 50, 100, 500, 1000, 5000, 10,000, and 15,000 ?g\\/g dry food. At the end of

K. S. El-Gendy; M. A. Radwan; A. F. Gad

2011-01-01

263

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

NASA Astrophysics Data System (ADS)

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

Verbitskaya, Olga; Manukovsky, Nickolay; Kovalev, Vladimir

264

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

PubMed

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

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

2012-01-01

265

Polymorphism and Population Density in the African Land Snail, Limicolaria martensiana.  

PubMed

In natural populations of the African land snail, Limicolaria martensiana, the degree of polymorphism in color and pattern may vary with the density of the population. This could occur because predators eat the snails selectively and use past experience as a guide in finding further prey. Hence contrasting color forms may be at an advantage in dense populations where predators would have ample opportunity to learn to recognize prey. PMID:17737105

Owen, D F

1963-05-10

266

Foraging trade-offs and resource patchiness: theory and experiments with a freshwater snail community  

Microsoft Academic Search

Empirical results concerning a freshwater snail community are interpreted using a two- species consumer model that incorporates resource structure. Behavioural-scale measurements on a guild of five species of freshwater pond snails (Mollusca: Pulmonata) indicate a trade-off between the ability to utilize a patch's resource and the ability to quickly find new resource patches. Community-level experiments demonstrate that both species richness

Jonathan M. Chase; Will G. Wilson; Shane A. Richards

2001-01-01

267

Dose-Dependent Effects of Cadmium on the Growth of Snails in Toxicity Bioassays  

Microsoft Academic Search

.   The effects on survival and growth of exposure to cadmium (Cd) in the food were analyzed in juvenile snails (age one month,\\u000a mean weight 1 g) of the two subspecies Helix aspersa aspersa (H.a.a.) and H. aspersa maxima (H.a.m.). The experiments lasted for four weeks and the animals were fed with special snail food containing 0-, 50-, 100-,\\u000a 200-,

A. Gomot

1997-01-01

268

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

PubMed Central

Parasitized individuals are often expected to be poor competitors because they are weakened by infections. Many trematode species, however, although extensively exploiting their mollusc hosts, also induce gigantism (increased host size) by diverting host resources towards growth instead of reproduction. In such systems, alternatively to reduced competitive ability due to negative effects of parasitism on host performance, larger size could allow more efficient resource acquisition and thus increase the relative competitive ability of host individuals. We addressed this hypothesis by testing the effect of a trematode parasite Diplostomum pseudospathaceum on the competitive ability of its snail host Lymnaea stagnalis. We experimentally examined the growth of snails kept in pairs in relation to their infection status and intensity of resource competition (i.e. food availability). We found that parasitized snails grew faster and their reproduction was reduced compared to unparasitized individuals indicating parasite-induced gigantism. However, growth of the snails was faster when competing with parasitized individuals compared to unparasitized snails indicating reduced competitive ability due to parasitism. The latter effect, however, was relatively weak suggesting that the effects of the parasite on snail physiology may partly override each other in determining competitive ability. PMID:24205383

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

2013-01-01

269

Molluscicidal activity of vulgarone B against ram's horn snail (Planorbella trivolvis).  

PubMed

The ram's horn snail (Planorbella trivolvis (Say)) is an intermediate host for a digenetic trematode (Bolbophorus confusus (Krause) Dubois) that has recently been discovered to be a significant problem in commercial channel catfish (Ictalurus punctatus Raf) production ponds in the Mississippi Delta region in the USA. In these catfish ponds, the digenetic life cycle of this parasitic trematode involves two intermediate hosts, the ram's horn snail and the channel catfish, and the final host, the American white pelican (Pelecanus erythrorhynchos Gmelin). One approach to eradicate this problem is to disrupt the life cycle of the parasitic trematodes by eliminating the snails. During our search for natural-product-based molluscicides to control the snails in the catfish ponds, vulgarone B, isolated from the steam distillate of the aerial parts of the plant Artemisia douglasiana Besser (Asteraceae), was found to be active towards the snails with a LC50 of ca 24 microM. Channel catfish toxicity studies indicated a LC50 of ca 207 microM. Vulgarone B may be an environmentally acceptable alternative for snail control in aquaculture. PMID:15154515

Meepagala, Kumudini M; Sturtz, George; Mischke, Charles C; Wise, David; Duke, Stephen O

2004-05-01

270

Studies of the snail vectors of bilharziasis mansoni in north-eastern Brazil  

PubMed Central

The authors describe the bilharziasis endemic areas in north-eastern Brazil, giving the rainfall and general characteristics of the climate. The life-cycles of the two snail vectors—Australorbis glabratus and Tropicorbis centimetralis—in Pernambuco are described. Considerable attention is given to the effects on the snails of the annual drought, which causes many of the habitats to dry up and seriously affects the snail life-cycles and survival patterns. The snails are able to populate habitats that are dry for 5-7 months every year. They survive during the dry season in the protection of debris, vegetation, etc. A. glabratus is more susceptible to infection with Schistosoma mansoni than is T. centimetralis, but the latter is an effective vector, nevertheless, probably because it often occurs in very large numbers. A. glabratus with mature infections die or lose their infections when removed from the water for 20-30 days. Immature parasites are not killed under the same conditions. Infection with S. mansoni injures the snails and may kill them. It also reduces the reproductive capacity of the vectors, but it does not permanently castrate them. The epidemiological significance of these findings and their meaning in terms of snail control are discussed. PMID:13573116

Barbosa, Frederico S.; Olivier, Louis

1958-01-01

271

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

PubMed Central

The gastrointestinal (GI) tract of invasive land snail Achatina fulica is known to harbor metabolically active bacterial communities. In this study, we assessed the bacterial diversity in the different regions of GI tract of Giant African snail, A. fulica by culture-independent and culture-dependent methods. Five 16S rRNA gene libraries from different regions of GI tract of active snails indicated that sequences affiliated to phylum ?-Proteobacteria dominated the esophagus, crop, intestine, and rectum libraries, whereas sequences affiliated to Tenericutes dominated the stomach library. On phylogenetic analysis, 30, 27, 9, 27, and 25 operational taxonomic units (OTUs) from esophagus, crop, stomach, intestine, and rectum libraries were identified, respectively. Estimations of the total bacterial diversity covered along with environmental cluster analysis showed highest bacterial diversity in the esophagus and lowest in the stomach. Thirty-three distinct bacterial isolates were obtained, which belonged to 12 genera of two major bacterial phyla namely ?-Proteobacteria and Firmicutes. Among these, Lactococcus lactis and Kurthia gibsonii were the dominant bacteria present in all GI tract regions. Quantitative real-time polymerase chain reaction (qPCR) analysis indicated significant differences in bacterial load in different GI tract regions of active and estivating snails. The difference in the bacterial load between the intestines of active and estivating snail was maximum. Principal component analysis (PCA) of terminal restriction fragment length polymorphism suggested that bacterial community structure changes only in intestine when snail enters estivation state. PMID:23233413

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

2012-01-01

272

Snail2/Slug cooperates with Polycomb repressive complex 2 (PRC2) to regulate neural crest development.  

PubMed

Neural crest cells arise from the border of the neural plate and epidermal ectoderm, migrate extensively and differentiate into diverse cell types during vertebrate embryogenesis. Although much has been learnt about growth factor signals and gene regulatory networks that regulate neural crest development, limited information is available on how epigenetic mechanisms control this process. In this study, we show that Polycomb repressive complex 2 (PRC2) cooperates with the transcription factor Snail2/Slug to modulate neural crest development in Xenopus. The PRC2 core components Eed, Ezh2 and Suz12 are expressed in the neural crest cells and are required for neural crest marker expression. Knockdown of Ezh2, the catalytic subunit of PRC2 for histone H3K27 methylation, results in defects in neural crest specification, migration and craniofacial cartilage formation. EZH2 interacts directly with Snail2, and Snail2 fails to expand the neural crest domains in the absence of Ezh2. Chromatin immunoprecipitation analysis shows that Snail2 regulates EZH2 occupancy and histone H3K27 trimethylation levels at the promoter region of the Snail2 target E-cadherin. Our results indicate that Snail2 cooperates with EZH2 and PRC2 to control expression of the genes important for neural crest specification and migration during neural crest development. PMID:25617436

Tien, Chih-Liang; Jones, Amanda; Wang, Hengbin; Gerigk, Magda; Nozell, Susan; Chang, Chenbei

2015-02-15

273

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

SciTech Connect

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

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

1994-01-01

274

[Dynamic transmission of Schistosoma by Biomphalaria pfeifferi in the region of Man in Côte d'Ivoire].  

PubMed

Intestinal schistosomiasis by Schistosoma mansoni is a parasitary affection transmitted in West Africa by the mollusc Biomphalaria pfeifferi. Transmission dynamic of schistosomiasis by Biomphalaria pfeifferi has seldom been investigated in Côte d'Ivoire. In the framework of a research project on the epidemiology of schistosomiasis in the natural forest ecosystems, this study was performed longitudinally over a period of three years in Man region, in western Côte d'Ivoire. The trial set up from 1986 to 1989 and the project was funded by the World Health Organization. The general objective is to design a strategy of schistosomiasis control based on chemotherapy. The approach aims at interrupting or considerably reducing the reinfections, prolonging in that way the duration of the positive effects of the chemotherapy. The specific objectives assigned to the work consisted in studying the dynamic of the B. pfeifferi population and the infection of B. pfeifferi. To achieve our objectives, diverse methods (i: the molluscs sampling by two prospectors during 15 minutes per study site and ii: individual isolation of molluscs in test tubes with 5 or 10 mL of filtered water and exposure to light) have been used. They enabled us in the sampling of the intermediary host molluscs of Schistosoma and seek their infections. The results show that apparent high densities of B. pfeifferi can be observed at the end of the dry season and at the beginning of rainy seasons. In addition, the variation of relative abundance of intermediary host molluscs of Schistosoma is significantly influenced by rainfall and the system of water ways. The period of transmission of the infection to man is six months at Gueupleu village and ten months at Botonguiné village. In order to optimize the effect of chemotherapy in these sites of transmission characterized by a high level of endemy (68 %), an extreme mobility of human populations and a multiplicity of contamination sites, this study should not only take into account the geographic space of the illness, but also it should eventually associate with a molluscicide action and/or a sanitary education through the teaching of primary health care. PMID:25351337

Yapi Yapi, G; Touré, M; Boka, O M; Tia, E; Boby, O A-M

2014-12-01

275

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

Microsoft Academic Search

This study aims to demonstrate the influence of the metabolic CO2 derived from the diet and of the atmospheric CO2 on the shell carbonate ?13C of the pulmonate snail Helix aspersa maxima raised under controlled conditions. Adult snails were analyzed and compared with three hatching and 1-day old young snails stemming from the same breeding. One day after, the 2-day

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

2003-01-01

276

Comparison of snail density, standing stock, and body size between Caribbean karst wetlands and other freshwater ecosystems  

Microsoft Academic Search

Synthesizing data from multiple studies generates hypotheses about factors that affect the distribution and abundance of species\\u000a among ecosystems. Snails are dominant herbivores in many freshwater ecosystems, but there is no comprehensive review of snail\\u000a density, standing stock, or body size among freshwater ecosystems. We compile data on snail density and standing stock, estimate\\u000a body size with their quotient, and

Clifton B. RuehlJoel; Joel C. Trexler

2011-01-01

277

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

PubMed Central

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

Yeung, Norine W; Hayes, Kenneth A

2013-01-01

278

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

PubMed

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

Pinto, Hudson Alves; Caffara, Monica; Fioravanti, Maria Letizia; de Melo, Alan L

2014-08-01

279

A phylogeny of the land snails (Gastropoda: Pulmonata).  

PubMed Central

We have undertaken the first large-scale molecular phylogenetic analysis of the Stylommatophora. Sequences of the ribosomal RNA gene-cluster were examined in 104 species of snails and slugs from 50 families, encompassing all the currently recognized major groups. It allows an independent test of the present classification based on morphology. At the level of families our molecular phylogeny closely supports the current taxonomy, but the deep branches within the tree do not. Surprisingly, a single assemblage including the families Achatinidae, Subulinidae and Streptaxidae lies near the base of the tree, forming a sister group to all remaining stylommatophorans. This primary division into 'achatinoid' and 'non-achatinoid' taxa is unexpected, and demands a radical reinterpretation of early stylommatophoran evolution. In particular, the Orthurethra appear to be relatively advanced within the 'non-achatinoid clade', and broadly equivalent to other super-familial clusters. This indicates that supposedly primitive features such as the orthurethran kidney are derived. The molecular tree also suggests that the origin of the Stylommatophora is much earlier than the main period of their diversification. PMID:11270439

Wade, C. M.; Mordan, P. B.; Clarke, B.

2001-01-01

280

Distribution of fasciolosis in Kansas, with results of experimental snail susceptibility studies.  

PubMed

A total of 278 veterinarians throughout Kansas were sent mail-in survey forms asking specific questions relating to their experience with fasciolosis in their practice area. Replies were received from 178 (64%) veterinarians representing six practice types; one-third reported having seen cases of fasciolosis in their practice. The results of our survey indicate that the majority of the cattle diagnosed with liver fluke disease in Kansas are imported from other areas of the USA. However, in both central and southeastern regions of Kansas, some cattle that had never been out of the state were infected with Fasciola hepatica. Thus, these areas of Kansas should be considered endemic for liver fluke disease. Methods of diagnosis, types of operations, and improvements seen after treatment were also discussed. In order to ascertain the existence of one or more possible snail intermediate hosts within Kansas, five species of lymnaeid snails were collected from central and southeastern parts of the state and tested for their susceptibility to infection by Fasciola hepatica. The snails collected included Pseudosuccinea columella, Fossaria obrussa, Fossaria bulimoides, Fossaria parva and Fossaria dalli. Of these, Pseudosuccinea columella and Fossaria bulimoides proved susceptible to experimental infection by Fasciola hepatica. Metacercariae obtained from experimentally infected snails were used to infect both a weanling calf thereby completing the life cycle of the parasite. This report is the first to identify the existence of suitable snail intermediate hosts for Fasciola hepatica in Kansas. PMID:7754605

McKown, R D; Ridley, R K

1995-02-01

281

Evaluation of environmental methods to control snails in an irrigation system in Central Morocco.  

PubMed

The Moroccan Ministry of Public Health has launched a programme to eliminate schistosomiasis. One of the components in this process is the control of Bulinus truncatus, the intermediate host snail of Schistosoma haematobium. We evaluated three environmentally safe measures to control B. truncatus in siphon boxes, the main breeding sites for these snails in the Tessaout Amont irrigation system. The first method involved covering the siphon boxes to exclude light and reduce algal growth, the second consisted of increasing the frequency of emptying and cleaning the siphon boxes, and the third method increased water velocity to hinder the establishment of the intermediate hosts. The results showed that covering had a pronounced effect on snail and egg mass density, was accepted by the local community and prevented water contact. Cleaning the siphons three times during the irrigation season led to a reduction in snail density although it was not statistically significant and recolonization was rapid. Increasing water velocity by reducing the dimensions of siphon boxes delayed recolonization, but such a control measure can be applied only in specific situations where it does not pose hydraulic problems. The three interventions were selectively effective against B. truncatus, whereas other snails such as Physa acuta and Lymnaea peregra were hardly affected. Covering, the most promising control measure, could be useful in the Moroccan schistosomiasis eradication programme. However, further investigations are needed to assess its impact on water quality. PMID:10995096

Laamrani, H; Khallaayoune, K; Boelee, E; Laghroubi, M M; Madsen, H; Gryseels, B

2000-08-01

282

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

PubMed Central

Snail is one of the important components of an aquatic ecosystem, it acts as intermediate host of Fasciola species. Control of snail population below a certain threshold level is one of the important methods in the campaign to reduce the incidence of fascioliasis. Life cycle of the parasite can be interrupted by killing the snail or Fasciola larva redia and cercaria in the snail body. In vivo and in vitro toxicity of the plant products and their active component such as citral, ferulic acid, umbelliferone, azadirachtin, and allicin against larva of Fasciola in infected snail Lymnaea acuminata were tested. Mortality of larvae were observed at 2?h, 4?h, 6?h, and 8?h, of treatment. In in vivo treatment, azadirachtin caused highest mortality in redia and cercaria larva (8?h, LC50 0.11, and 0.05?mg/L) whereas in in vitro condition allicin was highly toxic against redia and cercaria (8?h, LC50 0.01, and 0.009?mg/L). Toxicity of citral was lowest against redia and cercaria larva. PMID:22132306

Sunita, Kumari; Singh, D. K.

2011-01-01

283

Inhibiting interactions of lysine demethylase LSD1 with snail/slug blocks cancer cell invasion.  

PubMed

The process of epithelial-mesenchymal transition (EMT) which is required for cancer cell invasion is regulated by a family of E-box-binding transcription repressors, which include Snail (SNAIL1) and Slug (SNAI2). Snail appears to repress the expression of the EMT marker E-cadherin by epigenetic mechanisms dependent on the interaction of its N-terminal SNAG domain with chromatin-modifying proteins including lysine-specific demethylase 1 (LSD1/KDM1A). We assessed whether blocking Snail/Slug-LSD1 interaction by treatment with Parnate, an enzymatic inhibitor of LSD1, or TAT-SNAG, a cell-permeable peptide corresponding to the SNAG domain of Slug, suppresses the motility and invasiveness of cancer cells of different origin and genetic background. We show here that either treatment blocked Slug-dependent repression of the E-cadherin promoter and inhibited the motility and invasion of tumor cell lines without any effect on their proliferation. These effects correlated with induction of epithelial and repression of mesenchymal markers and were phenocopied by LSD1 or Slug downregulation. Parnate treatment also inhibited bone marrow homing/engraftment of Slug-expressing K562 cells. Together, these studies support the concept that targeting Snail/Slug-dependent transcription repression complexes may lead to the development of novel drugs selectively inhibiting the invasive potential of cancer cells. PMID:23054398

Ferrari-Amorotti, Giovanna; Fragliasso, Valentina; Esteki, Roza; Prudente, Zelia; Soliera, Angela Rachele; Cattelani, Sara; Manzotti, Gloria; Grisendi, Giulia; Dominici, Massimo; Pieraccioli, Marco; Raschellà, Giuseppe; Chiodoni, Claudia; Colombo, Mario Paolo; Calabretta, Bruno

2013-01-01

284

Isolation of a phosphoryl choline-binding protein from the hemolymph of the snail, Achatina fulica.  

PubMed

A phosphorylcholine-binding protein from the hemolymph of the snail Achatina fulica was purified to near homogeneity using a Sepharose phenylphosphorylcholine affinity column. The protein bound to the affinity column was eluted with 5 mM phosphorylcholine as a single symmetrical peak. The purified protein (400 Kda) contained 35-40% carbohydrate. On SDS-PAGE the protein separated into two bands of 20 and 24 Kda, and had a pI of 5.9. On immunodiffusion, antiserum to the snail phosphorylcholine binding protein did not cross-react against other phosphorylcholine binding proteins, like rat serum phosphorylcholine-binding protein (PCBP), limulus C-reactive protein (CRP), or human CRP. On pretreatment of the snail hemolymph with this antiserum, the hemagglutination titer of the hemolymph was markedly decreased. The purified snail phosphorylcholine binding protein agglutinated rabbit erythrocytes in the absence of divalent cation (Ca+2) but trace amount of Ca+2 increased its binding. The strongest inhibitor of the agglutination reaction was lactose, followed by melibiose and 2-deoxygalactose. The relationships of the snail phosphorylcholine binding protein to other hemolymph agglutinins and to CRPs are discussed in light of common phylogeny. PMID:1773848

Mandal, C; Biswas, M; Nagpurkar, A; Mookerjea, S

1991-01-01

285

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

PubMed

Freshwater snails have received much attention for their role as intermediate hosts for trematodes causing disease in people and animals such as schistosomiasis and various food-borne trematodes. While effective medical treatment exists for some of these diseases there is need for preventive measures to reduce transmission, e.g. control of intermediate hosts because transmission patterns are often complicated due to presence of reservoir final hosts. In order to implement control measures against the intermediate host snails with minimal impact on the freshwater ecosystems and their biodiversity, a profound knowledge on transmission patterns of the trematodes is required and this is partly related to distribution, habitat preferences, and seasonal variation in density of the intermediate host species. Identification of snail species can be problematic on the basis of morphological and anatomical characters alone as some species show morphological plasticity and similarly morphological differentiation of cercariae found in snails may be difficult and this could lead to biased perceptions of intermediate host spectra and transmission patterns. In this paper, we give an overview of the snail families and their medical and veterinary importance in Asia but with main focus on Vietnam. PMID:25149356

Madsen, H; Hung, N M

2014-12-01

286

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

PubMed

More than 100 species of venomous cone snails (genus Conus) are highly effective predators of fish. The vast majority of venom components identified and functionally characterized to date are neurotoxins specifically targeted to receptors, ion channels, and transporters in the nervous system of prey, predators, or competitors. Here we describe a venom component targeting energy metabolism, a radically different mechanism. Two fish-hunting cone snails, Conus geographus and Conus tulipa, have evolved specialized insulins that are expressed as major components of their venoms. These insulins are distinctive in having much greater similarity to fish insulins than to the molluscan hormone and are unique in that posttranslational modifications characteristic of conotoxins (hydroxyproline, ?-carboxyglutamate) are present. When injected into fish, the venom insulin elicits hypoglycemic shock, a condition characterized by dangerously low blood glucose. Our evidence suggests that insulin is specifically used as a weapon for prey capture by a subset of fish-hunting cone snails that use a net strategy to capture prey. Insulin appears to be a component of the nirvana cabal, a toxin combination in these venoms that is released into the water to disorient schools of small fish, making them easier to engulf with the snail's distended false mouth, which functions as a net. If an entire school of fish simultaneously experiences hypoglycemic shock, this should directly facilitate capture by the predatory snail. PMID:25605914

Safavi-Hemami, Helena; Gajewiak, Joanna; Karanth, Santhosh; Robinson, Samuel D; Ueberheide, Beatrix; Douglass, Adam D; Schlegel, Amnon; Imperial, Julita S; Watkins, Maren; Bandyopadhyay, Pradip K; Yandell, Mark; Li, Qing; Purcell, Anthony W; Norton, Raymond S; Ellgaard, Lars; Olivera, Baldomero M

2015-02-10

287

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

PubMed Central

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

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

2014-01-01

288

Seasonal dynamics of two mortality-related trematodes using an introduced snail.  

PubMed

Seasonal dynamics of 2 trematode species, Cyathocotyle bushiensis and Sphaeridiotrema globulus, were assessed in relation to life history traits of the parasites and their hosts, as well as abundance of host species and abundance of infective stages. Both of these trematodes are associated with recurrent mortality of migrating waterbirds on the Upper Mississippi River National Wildlife and Fish Refuge. An invasive snail species, Bithynia tentaculata, serves as intermediate host for both trematode species. In total, 2,970 snails were collected at 2 study sites. Prevalence and mean abundance of the 2 trematode species varied among dates and was attributed to several factors, including migration patterns of definitive hosts, snail population dynamics, and seasonal changes in temperature. The surge of new infections of both parasites seems to be due to avian hosts foraging at this site during spring migration. The high prevalence and abundance of metacercariae among the snail population promote mortality among molluscivorous birds by increasing the probability of ingestion of a lethal dose. Additionally, mortality of non-molluscivorous birds can be explained by accidental ingestion of a couple of highly infected snails resulting in a lethal dose. PMID:20049988

Herrmann, Kristin K; Sorensen, Robert E

2009-08-01

289

Adenine nucleotides in snail muscles as one of biomarkers of fluoride toxicity.  

PubMed

The aim of this work was to determine the extent of bioaccumulation of fluorides in tissues of Helix aspersa maxima. The toxicity of fluorides administered orally on the energy balance of the snail's foot was investigated based on measurements of concentrations of adenine nucleotides and their metabolism degradation products. Quantitation of fluoride levels was done in soft tissues (foot, hepatopancreas) and shells of mature snails. Qualitative and quantitative analysis of purine compounds was performed in slices of foot from mature snails. Fluoride concentrations in pulverized shells were measured using an ion-selective electrode. Gas chromatography was used to determine fluoride concentrations in soft tissues (hepatopancreas and foot). Purines were measured in foot muscle slices with high-performance liquid chromatography (HPLC). Fluoride levels in soft tissues of the snail cannot serve as an indicator for biomonitoring purposes as no significant accumulation was observed during exposure to maximum allowable concentrations of fluoride in drinking water. Contrary to this, levels of fluoride in the shell rose significantly with this concentration of fluoride in drinking water. The effect of fluorides on energy metabolism of foot muscle was evidenced by elevated AMP levels, increased adenine nucleotide pool and reduced conversion of ADP to ATP. Exposure to rising F(-) concentrations was accompanied by decreasing values of the adenylate energy charge AEC. Determination of AMP or AEC in foot muscle of exposed snails seems to be a useful indicator of fluoride effects on metabolic activity. PMID:15931426

Rac, Monika; Safranow, Krzysztof; Jakubowska, Katarzyna; Chlubek, Dariusz; Machoy, Zygmunt

2005-06-01

290

A Snail1/Notch1 Signaling Axis Controls Embryonic Vascular Development  

PubMed Central

Notch1-Delta-like 4 (Dll4) signaling controls vascular development by regulating endothelial cell (EC) targets that modulate vessel wall remodeling and arterial-venous specification. The molecular effectors that modulate Notch signaling during vascular development remain largely undefined. Here we demonstrate that the transcriptional repressor, Snail1, acts as a VEGF-induced regulator of Notch1 signaling and Dll4 expression. EC-specific Snail1 loss-of-function conditional knockout mice die in utero with defects in vessel wall remodeling in association with losses in mural cell investment and disruptions in arterial-venous specification. Snail1 loss-of-function conditional knockout embryos further display up-regulated Notch1 signaling and Dll4 expression that is partially reversed by inhibiting ?-secretase activity in vivo with Dll4 identified as a direct target of Snail1-mediated transcriptional repression. These results document a Snail1-Dll4/Notch1 axis that controls embryonic vascular development. PMID:24894949

Wu, Zhao-Qiu; Rowe, R. Grant; Lim, Kim-Chew; Lin, Yongshun; Willis, Amanda; Tang, Yi; Li, Xiao-Yan; Nor, Jacques E; Maillard, Ivan; Weiss, Stephen J

2014-01-01

291

Application of Failure Mode and Effect Analysis (FMEA) and Cause and Effect Analysis in Conjunction with ISO 22000 to a Snails (Helix aspersa) Processing Plant; A Case Study  

Microsoft Academic Search

Failure Mode and Effect Analysis (FMEA) has been applied for the risk assessment of snails manufacturing. A tentative approach of FMEA application to the snails industry was attempted in conjunction with ISO 22000.Preliminary Hazard Analysis was used to analzse and predict the occurring failure modes in a food chain system (snails processing plant), based on the functions, characteristics, and\\/or interactions

Ioannis S. Arvanitoyannis; Theodoros H. Varzakas

2009-01-01

292

A Copper Sulfate?Citric Acid Pond Shoreline Treatment to Control the Rams-Horn Snail Planorbella trivolvis  

Microsoft Academic Search

The rams-horn snail Planorbella trivolvis carries at least two important digenetic trematodes that infect propagated fish species in the southeastern United States. These snails are found in fish production ponds, and there are no proven chemical methods for eliminating them that would not also kill the fish. Application of an aqueous solution of 589 g of copper sulfate and 58.9

Andrew J. Mitchell

2002-01-01

293

Fecal bacterial contamination in natural water reservoirs as an indicator of seasonal infection by Opisthorchis viverrini in snail intermediate hosts  

Microsoft Academic Search

Opisthorchis viverrini, a carcinogenic liver fluke, requires Bithynia snails as the first intermediate host, which release cercariae after ingesting fluke eggs from contaminated water. Fecal bacterial contamination and O. viverrini-infected Bithynia snails were investigated in samples collected from natural water reservoirs in Ban Phai, Chonnabot and Muang Districts (Ban Lerngpeuy) in Khon Kaen Province, northeast Thailand, where there is a

Wanlop Kaewkes; Sasithorn Kaewkes; Smarn Tesana; Thewarach Laha; Banchob Sripa

294

Failure of transmission of low-pathogenic avian influenza virus between Mallards and freshwater snails: an experimental evaluation.  

PubMed

In aquatic bird populations, the ability of avian influenza (AI) viruses to remain infectious in water for extended periods provides a mechanism that allows viral transmission to occur long after shedding birds have left the area. However, this also exposes other aquatic organisms, including freshwater invertebrates, to AI viruses. Previous researchers found that AI viral RNA can be sequestered in snail tissues. Using an experimental approach, we determined whether freshwater snails (Physa acuta and Physa gyrina) can infect waterfowl with AI viruses by serving as a means of transmission between infected and naïve waterfowl via ingestion. In our first experiment, we exposed 20 Physa spp. snails to an AI virus (H3N8) and inoculated embryonated specific pathogen-free (SPF) chicken eggs with the homogenized snail tissues. Sequestered AI viruses remain infectious in snail tissues; 10% of the exposed snail tissues infected SPF eggs. In a second experiment, we exposed snails to water contaminated with feces of AI virus-inoculated Mallards (Anas platyrhynchos) to evaluate whether ingestion of exposed freshwater snails was an alternate route of AI virus transmission to waterfowl. None of the immunologically naïve Mallards developed an infection, indicating that transmission via ingestion likely did not occur. Our results suggest that this particular trophic interaction may not play an important role in the transmission of AI viruses in aquatic habitats. PMID:24502718

Oesterle, Paul T; Huyvaert, Kathryn P; Orahood, Darcy; Mooers, Nicole; Sullivan, Heather; Franklin, Alan B; Root, J Jeffrey

2013-10-01

295

Size-fecundity relationships in the land snail Helix aspersa: preliminary results on a form outside the norm  

Microsoft Academic Search

Reproductive traits of the land snail Helix aspersa Müller were investigated under artificial conditions in a breeding population of a giant subspecies from North Africa, namely Helix aspersa maxima. The results were compared with data obtained from experiments conducted under the same experimental with the common form Helix aspersa aspersa from (1) a population from the same snail farm, which

LUC MADEC; ANNIE GUILLER; MARIE-AGNES COUTELLEC-VRETO; CHRISTOPHE DESBUQUOIS

1998-01-01

296

Influence of diets enriched with different vegetable oils on the fatty acid profiles of snail He lix aspersa maxima  

Microsoft Academic Search

The proximate analyses and fatty acid profiles of snail (Helix aspersa maxima) muscle submitted to different feedings with diets enriched with 3% of different vegetable oils (canola, soybean, flaxseed, sunflower, maize and rice) were analysed. The lowest value of lipids was in the snail muscle of the treatment enriched with soybean oil. The main fatty acids detected were palmitic (C16:0),

Maria Cristina Milinsk; Roseli das Graças Padre; Carmino Hayashi; Nilson Evelázio de Souza; Makoto Matsushita

2003-01-01

297

Shell of snail Helix aspersa maxima (Helicidae) as a protection of bioaccumulation toxic sodium fluoride in soft tissue.  

PubMed

The aim of this work was to determine the extent of bioaccumulation of sodium fluorides in tissues of snails under strictly controlled conditions, and also to determine resistance and tolerance to sodium fluoride load in these organisms. The study was performed on snails removed from aestivation. Quantitation of fluoride levels was done in soft tissues (foot, hepatopancreas) and shells of mature snails. Results show that long exposure to sodium fluoride pollution at a low level results in accumulation principally in the soft tissues of the snails. Because of the possibility of fluoride accumulation in the foot, the number of snails used for culinary purposes must be controlled, as it can potentially cause chronic toxemia caused by this trace element. Results also show that the shells of snails offer protection against the bioaccumulation of toxic fluoride in the soft tissue. The Helix aspersa maxima snail is characterised by high resistance and tolerance to fluoride load. Fluoride levels in soft tissues of the snail cannot serve as an indicator for biomonitoring purposes. In contrast, levels in the shell rose significantly with the concentration of fluoride and can be used in biomonitoring of sodium fluoride pollution. PMID:19058550

Ra?, Monika Ewa; Stachowska, Ewa; Machoy, Zygmunt

2005-01-01

298

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

PubMed

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. PMID:20236558

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

2010-12-01

299

Hatching of Echinostoma trivolvis miracidia in response to snail host and non-host chemical cues.  

PubMed

Environmental cues are used by many organisms to time life history transitions and can be important for trematode host location. However, while much is understood about how larval trematodes locate hosts, much less is known about the potential role of host cues in the timing of trematode egg development and hatching. We addressed the potential role of host chemical cues in mediating hatching of Echinostoma trivolvis miracidia by comparing hatching in response to cues from the first intermediate host (the snail Planorbella trivolvis), a non-host snail (the snail Goniobasis proxima), and a non-host invertebrate (earthworm, Lumbricus terrestris). We hypothesized that in the presence of cues from their first intermediate host, E. trivolvis would hatch sooner and would be more synchronized than when host cues were absent. However, we found that hatching was unaffected by our cue treatments. In all treatments, hatching uniformly began at 13 days and was nearly evenly spread over the next 3 weeks. PMID:19513751

Belden, Lisa K; Widder, Pamela D; Fischer, Lauren R; Carter, Ashlee B; Wojdak, Jeremy M

2009-09-01

300

Association between shell morphology of micro-land snails (genus Plectostoma) and their predator's predatory behaviour.  

PubMed

Predator-prey interactions are among the main ecological interactions that shape the diversity of biological form. In many cases, the evolution of the mollusc shell form is presumably driven by predation. However, the adaptive significance of several uncommon, yet striking, shell traits of land snails are still poorly known. These include the distorted coiled "tuba" and the protruded radial ribs that can be found in micro-landsnails of the genus Plectostoma. Here, we experimentally tested whether these shell traits may act as defensive adaptations against predators. We characterised and quantified the possible anti-predation behaviour and shell traits of Plectostoma snails both in terms of their properties and efficiencies in defending against the Atopos slug predatory strategies, namely, shell-apertural entry and shell-drilling. The results showed that Atopos slugs would first attack the snail by shell-apertural entry, and, should this fail, shift to the energetically more costly shell-drilling strategy. We found that the shell tuba of Plectostoma snails is an effective defensive trait against shell-apertural entry attack. None of the snail traits, such as resting behaviour, shell thickness, shell tuba shape, shell rib density and intensity can fully protect the snail from the slug's shell-drilling attack. However, these traits could increase the predation costs to the slug. Further analysis on the shell traits revealed that the lack of effectiveness in these anti-predation shell traits may be caused by a functional trade-off between shell traits under selection of two different predatory strategies. PMID:24749008

Liew, Thor-Seng; Schilthuizen, Menno

2014-01-01

301

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

PubMed Central

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

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

2012-01-01

302

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

PubMed Central

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

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

2014-01-01

303

Inhibition kinetics of certain organophosphorus and carbamate pesticides on acetylcholinesterase from the snail Lymnaea acuminata.  

PubMed

k2, Kd and ki, for 2 organophosphorus (Phorate and Formothion) and 2 carbamate pesticides (Mexacarbate and Carbaryl) using acetylcholinesterase present in homogenates of the nervous tissue of the snail Lymnaea acuminata, were determined. Calculation of zero time velocities demonstrated that even in their P-S form the organophosphate compounds inhibited snail acetylcholinesterase. The kinetic constants of the 2 carbamates have been explained on the basis of their structure. The toxicity of the 4 pesticides has been explained on the basis of their kinetic constants. PMID:6658844

Singh, D K; Agarwal, R A

1983-12-01

304

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

PubMed Central

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

2014-01-01

305

HMGA2 and Smads Co-regulate SNAIL1 Expression during Induction of Epithelial-to-Mesenchymal Transition*S?  

PubMed Central

Epithelial-mesenchymal transition (EMT) is important during embryonic cell layer movement and tumor cell invasiveness. EMT converts adherent epithelial cells to motile mesenchymal cells, favoring metastasis in the context of cancer progression. Transforming growth factor-? (TGF-?) triggers EMT via intracellular Smad transducers and other signaling proteins. We previously reported that the high mobility group A2 (HMGA2) gene is required for TGF-? to elicit EMT in mammary epithelial cells. In the present study we investigated the molecular mechanisms by which HMGA2 induces EMT. We found that HMGA2 regulates expression of many important repressors of E-cadherin. Among these, we analyzed in detail the zinc-finger transcription factor SNAIL1, which plays key roles in tumor progression and EMT. We demonstrate that HMGA2 directly binds to the SNAIL1 promoter and acts as a transcriptional regulator of SNAIL1 expression. Furthermore, we observed that HMGA2 cooperates with the TGF-?/Smad pathway in regulating SNAIL1 gene expression. The mechanism behind this cooperation involves physical interaction between these factors, leading to an increased binding of Smads to the SNAIL1 promoter. SNAIL1 seems to play the role of a master effector downstream of HMGA2 for induction of EMT, as SNAIL1 knock-down partially reverts HMGA2-induced loss of epithelial differentiation. The data propose that HMGA2 acts in a gene-specific manner to orchestrate the transcriptional network necessary for the EMT program. PMID:18832382

Thuault, Sylvie; Tan, E-Jean; Peinado, Hector; Cano, Amparo; Heldin, Carl-Henrik; Moustakas, Aristidis

2008-01-01

306

Pseudechinoparyphium echinatum (Digenea: Echinostomatidae): experimental observations on cercarial specificity toward second intermediate hosts.  

PubMed

Infectivity of Pseudechinoparyphium echinatum cercariae to 11 species of gastropod was examined experimentally. Broad specificity and differential host-parasite compatibility were exhibited. Nine gastropod species functioned as second intermediate hosts. Planorbarius corneus, Physa fontinalis, Lymnaea peregra and Biomphalaria alexandrina showed high levels of compatibility with the parasite. In single-species exposures over 90% of cercariae encysted in each of these hosts. Low compatibility with the first intermediate host species Lymnaea stagnalis may be a mechanism preventing super-infection of emitting snails. Cercariae did not infect the prosobranchs Bithynia tentaculata and Viviparus viviparus. Experimental infection of a host community comprised of 8 European gastropod species revealed an order of host utilization similar to that shown in single-species exposures. However, cercarial transmission success in P. fontinalis and L. peregra (compared to that in P. corneus) was significantly reduced. This may have been due to the marked preference of cercariae for P. corneus compared to the other two highly suitable hosts for whom cercariae showed equal preference. PMID:2362767

McCarthy, A M; Kanev, I

1990-06-01

307

Biotic interactions modify the transfer of cesium-137 in a soil-earthworm-plant-snail food web.  

PubMed

The present study investigated the possible influence of the earthworm Aporrectodea tuberculata on the transfer of cesium-137 ((137)Cs) from a contaminated (130 Bq/kg) deciduous forest soil to the lettuce Lactuca sativa and to the snail Cantareus aspersus (formerly Helix aspersa) in two laboratory experiments. In the first experiment, the International Organization for Standardization 15952 test was used to expose snails for five weeks to contaminated soil with or without earthworms. In these conditions, the presence of earthworms caused a two- to threefold increase in (137)Cs concentrations in snails. Transfer was low in earthworms as well as in snails, with transfer factors (TFs) lower than 3.7 x 10(-2). Activity concentrations were higher in earthworms (2.8- 4.8 Bq/kg dry mass) than in snails (<1.5 Bq/kg). In the second experiment, microcosms were used to determine the contribution of soil and lettuce in the accumulation of (137)Cs in snails. Results suggest that the contribution of lettuce and soil is 80 and 20%, respectively. Microcosms also were used to study the influence of earthworms on (137)Cs accumulation in snail tissues in the most ecologically relevant treatment (soil-earthworm-plant-snail food web). In this case, soil-to-plant transfer was high, with a TF of 0.8, and was not significantly modified by earthworms. Conversely, soil-to-snail transfer was lower (TF, approximately 0.1) but was significantly increased in presence of earthworms. Dose rates were determined in the microcosm study with the EDEN (elementary dose evaluation for natural environment) model. Dose rates were lower than 5.5 x 10(-4) mGy/d, far from values considered to have effects on terrestrial organisms (1 mGy/d). PMID:18266477

Fritsch, Clémentine; Scheifler, Renaud; Beaugelin-Seiller, Karine; Hubert, Philippe; Coeurdassier, Michaël; de Vaufleury, Annette; Badot, Pierre-Marie

2008-08-01

308

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

PubMed Central

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

2014-01-01

309

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

PubMed Central

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

Price, Melissa R.; Hadfield, Michael G.

2014-01-01

310

Trait compensation and cospecialization in a freshwater snail: size, shape and antipredator behaviour  

Microsoft Academic Search

We examined relationships between individual differences in antipredator behaviour and prey morphological characters (size, shape) that influence prey vulnerability. Behavioural responses of Physa gyrina to chemical cues associated with predation by crayfish Orconectes rusticus, were assayed in the laboratory for 6 days over a 13-day period. Snails displayed consistent, individually repeatable responses to the predation cues, including hiding (refuge use)

Thomas J. Dewitt; Andrew Sih; Jeffrey A. Hucko

1999-01-01

311

Evaluating Pond Shoreline Treatments of Slurried Hydrated Lime for Reducing Marsh Rams-Horn Snail Populations  

Microsoft Academic Search

Trematode parasites can cause massive infections in commercially raised fish. The most promising approach for the control of these infections is the reduction or elimination of snails that serve as vectors for the trematodes. A recent approach, the application of high concentrations of slurried hydrated lime (SHL) or copper sulfate pentahydrate (CSP) along pond margins (shoreline treatment), has shown promise

Andrew J. Mitchell; Scott Snyder; David J. Wise; Charles C. Mischke

2007-01-01

312

Sensitive and species-specific detection of Clonorchis sinensis by PCR in infected snails and fishes  

Microsoft Academic Search

In the present study, PCR procedures have been established for a rapid and easy preparation of DNA of parasite stages from\\u000a the intermediate hosts, i.e. sporocysts and rediae in snails and metacercariae in fishes. Primers have been developed, which\\u000a enable a highly sensitive and species-specific detection of Clonorchis sinensis.

Boris Müller; Jürgen Schmidt; Heinz Mehlhorn

2007-01-01

313

The toxic activities of Arisaema erubescens and Nerium indicum mixed with Streptomycete against snails.  

PubMed

The comparative molluscicidal activities of Arisaema erubescens tuber extracts and Nerium indicum leaf extracts mixed with Streptomycete violacerruber dilution (SD) against the snail Oncomlania hupensis and the responses of the isozymes, esterase (EST) and superoxide dismutase (SOD) to the A. erubescens extracts and the mixtures were investigated. The molluscicidal activity of A. erubescens water extracts mixed with S. violacerruber dilution was 4-5 times higher than a single A. erubescens or S. violacerruber dilution after 24-h exposure, and is also higher than that of N. indicum leaf water extracts mixed with S. violacerruber dilution. At the end of exposure to the N-butanol extracts of A. erubescens tubers (NEAT), the EST activity in snail liver decreased and some enzyme bands (EST 1 and EST 3 in exposure to NEAT) disappeared but the activities of SOD 1 increased. The effect was more obvious in mixture treatment than in single NEAT or SD treatment. The results indicated that molluscicidal activities of plant and microorganism could be more effective than single plant. The decline of the detoxic ability in snail liver cells could be the reason of the snail dying. PMID:21783953

Zhang, Yi; Ke, Wenshan; Yang, Jinglian; Ma, Anning; Yu, Zhensen

2009-03-01

314

Accumulation of cadmium and copper by the terrestrial snail Arianta arbustorum L.: kinetics and budgets  

Microsoft Academic Search

Specimens of the terrestrial gastropod Arianta arbustorum were fed on cadmium- or copper-enriched agar plates with the aim of performing an input\\/output analysis and of studying the distribution of these metals in several organs of the snails. After a feeding period of 20 days about 45% of cadmium were lost. 36% accumulated in the hepatopancreas, where a cadmium concentration of

Burkhard Berger; Reinhard Dallinger

1989-01-01

315

Metapopulation genetic structure and migration pathways in the land snail Helix aspersa: influence of landscape heterogeneity  

Microsoft Academic Search

The spatial genetic structuring of the land snail Helix aspersa was investigated for 32 colonies within an intensive agricultural area, the polders of the Bay of Mont-Saint-Michel (France). Given the habitat patchiness and envi- ronmental instability, the setting of H. aspersa colonies meets the broader view of a metapopulation structure. The identification of extrinsic barriers to migration and their impact

Jean-François Arnaud

2003-01-01

316

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

SciTech Connect

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

Jay, E.A. [North Carolina Univ., Chapel Hill, NC (United States)

1993-10-01

317

Snails avoid the medulla of Lobaria pulmonaria and L. scrobiculata due to presence of secondary compounds  

Microsoft Academic Search

Lichens are frequently grazed by various invertebrates, such as snails and slugs. However, these gastropods discriminate between the various layers of the lichen thallus. Likewise, carbon based secondary compounds (CBSCs), some of which are known to deter lichenivores, are unevenly distributed between the various layers. In this study, the degree of rejection of medullary CBSCs by gastropods is investigated. The

Johan Asplund

2011-01-01

318

EFFECTS OF COPPER, NICKEL AND ZINC ON THREE SPECIES OF OREGON FRESHWATER SNAILS  

EPA Science Inventory

Three snail species collected from western Oregon were exposed to metals - Juga plicifera and Lithoglyphus virens, which inhabit cool coastal streams, and Physa gyrina, which is found in Willamette Valley ponds. J. plicifera were exposed in flow-through laboratory tests to copper...

319

Inhibiting interactions of lysine demethylase LSD1 with Snail/Slug blocks cancer cell invasion  

PubMed Central

The process of epithelial-mesenchymal transition (EMT) which is required for cancer cell invasion is regulated by a family of E-box binding transcription repressors which include Snail (SNAI) and Slug (SNAI2). Snail appears to repress the expression of the EMT marker E-cadherin by epigenetic mechanisms dependent on the interaction of its N-terminal SNAG domain with chromatin modifying proteins including lysine specific demethylase 1 (LSD1/KDM1A). We assessed whether blocking Snail/Slug-LSD1 interaction by treatment with Parnate, an enzymatic inhibitor of LSD1, or TAT-SNAG, a cell-permeable peptide corresponding to the SNAG domain of Slug, suppresses the motility and invasiveness of cancer cells of different origin and genetic background. We show here that either treatment blocked Slug-dependent repression of the E-cadherin promoter and inhibited the motility and invasion of tumor cell lines without any effect on their proliferation. These effects correlated with induction of epithelial and repression of mesenchymal markers and were phenocopied by LSD1 or Slug down-regulation. Parnate treatment also inhibited bone marrow homing/engraftment of Slug-expressing K562 cells. Together, these studies support the concept that targeting Snail/Slug-dependent transcription repression complexes may lead to the development of novel drugs selectively inhibiting the invasive potential of cancer cells. PMID:23054398

Ferrari-Amorotti, Giovanna; Fragliasso, Valentina; Esteki, Rosa; Prudente, Zelia; Soliera, Angela Rachele; Cattelani, Sara; Manzotti, Gloria; Grisendi, Giulia; Dominici, Massimo; Pieraccioli, Marco; Raschellà, Giuseppe; Chiodoni, Claudia; Colombo, Mario Paolo; Calabretta, Bruno

2012-01-01

320

An improved 2-phase snail-cam type fan motor design  

Microsoft Academic Search

This paper deals with the design of a 2-phase switched reluctance motor (SRM) used for the cooling fan motor of a refrigerator. To reduce the dead zone and improve the efficiency, the snail-cam type rotor pole and the asymmetric stator pole are investigated. For the optimal shape design, the performances of each model are obtained from numerical calculation results by

Ji-Young Lee; Geun-Ho Lee; Jeong-Jong Lee; Jung-Pyo Hong; Kyung-Ho Ha

2003-01-01

321

USING LARVAL TREMATODES THAT PARASITIZE SNAILS TO EVALUATE A SALTMARSH RESTORATION PROJECT  

Microsoft Academic Search

We conducted a Before-After-Control-Impact (BACI) study using larval di- geneans infecting the California horn snail, Cerithidea californica, to evaluate the success of an ecological restoration project at Carpinteria Salt Marsh in California, USA. Digenean trematodes are parasites with complex life cycles requiring birds and other vertebrates as final hosts. We tested two hypotheses for prevalence and species richness of larval

Todd C. Huspeni; Kevin D. Lafferty

2004-01-01

322

The effect of earthworms and snails in a simple plant community  

Microsoft Academic Search

Snails and earthworms affected the dynamics of a simple, three-species plant community, in the Ecotron controlled environment facility. Earthworms enhanced the establishment, growth and cover of the legume Trifolium dubium, both via the soil and interactions with other plant species. Worms increased soil phosphates, increased root nodulation in T. dubium, and enabled T. dubium seedlings to establish in the presence

Lindsey Thompson; Chris D. Thomas; Julie M. A. Radley; Sarah Williamson; John H. Lawton

1993-01-01

323

Transmission control of schistosomiasis japonica: implementation and evaluation of different snail control interventions  

Microsoft Academic Search

The great progress made in the control of schistosomiasis japonica in China is to some extent explained by successful intermediate host snail control, in particular with environmental management commencing some 50 years ago. By 1995, interruption of Schistosoma japonicum transmission had been achieved in five of the 12 schistosome-endemic provinces while endemic areas in the remaining provinces had been reduced

Yi Yuan; Xing-Jian Xu; Hui-Fen Dong; Ming-Sen Jiang; Hui-Guo Zhu

2005-01-01

324

Foraging by the mud snail, Ilyanassa obsoleta (Say), modulates spatial variation in benthic community structure  

Microsoft Academic Search

We investigated the foraging behavior of the mud snail, Ilyanassa obsoleta, and its consequences for macrobenthic community structure on mud flats on Long Island, NY, USA. Field sampling demonstrated strong spatial heterogeneity in the population densities of I. obsoleta. We experimentally tested three hypotheses: (i) I. obsoleta are strongly attracted to areas with high levels of detritus; (ii) local abundances

Brendan P. Kelaher; Jeffrey S. Levinton; J. Matthew Hoch

2003-01-01

325

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

E-print Network

Intervention Analysis of Hurricane Effects on Snail Abundance in a Tropical Forest Using Long or rain, or indi- rectly, by altering the abiotic environment, habitat structure, resource availability-Term Spatiotemporal Data Marcos O. PRATES, Dipak K. DEY, Michael R. WILLIG, and Jun YAN Large-scale natural

Willig, Michael

326

Interrelationships of the emotionally positive and negative regions of the brain of the edible snail  

Microsoft Academic Search

The changes in the behavior of the garden snail during self-stimulation through electrodes chronically implanted in specific regions of the brain are described in this study. The stimulation of the mesocerebral region led to an increase in the frequency of reinforced behavior, whereas stimulation of the rostral portion of the parietal ganglia led to a decrease in the frequency of

P. M. Balaban; R. Chase

1991-01-01

327

Crawling beneath the free surface: Water snail locomotion Sungyon Lee,1  

E-print Network

onto a solid substrate. Since a free surface cannot support shear stress, adhesive locomotion by a thin layer of mucus. Here, a lubrication model is used to describe the mucus flow in the limit of small the snail's foot deforms the free surface, thereby generating curvature pressures and lubrication flows

Lauga, Eric

328

SMALL-SCALE DISTRIBUTION OF WINTERING TERRESTRIAL SNAILS IN FOREST SITE: RELATION TO HABITAT CONDITIONS  

Microsoft Academic Search

The aim of our study was to as- sess the small scale distribution (up to several m 2 ) of hibernating forest-dwelling snails in relation to small-scale environmental factors, like litter com- position, soil temperature and humidity or vegeta- tion cover. The study was conducted in the \\

Krystyna SZYBIAK

2009-01-01

329

Within-reach spatial variability of snails and molluscivory by brown trout  

Microsoft Academic Search

Linking habitat distributions of prey to the probability of predation is important to understanding consumptive effects of predators on prey populations. This study reports how within-reach spatial variability of two snails, the hydrobiid Potamopyrgus antipodarum and the physid Physella acuta, was linked to habitat-based predation risk by young brown trout (Salmo trutta) of different age classes. Potamopyrgus is endemic to

Joseph R Holomuzki

2010-01-01

330

Larval dermestid beetles feeding on nestling snail kites, wood storks, and great blue herons  

USGS Publications Warehouse

In recent years abdominal lesions attributable to larval dermestid beetles (D. nidum) have appeared in nestling snail (Everglade) kites (R. sociabilis), wood storks (M. americana) and great blue herons (A. herodias). Although it appears that most nestlings affected have survived, the degree of threat posed by dermestid larvae to various avian species is as yet unclear.

Snyder, N.F.R.; Ogden, J.C.; Bittner, J.D.; Grau, G.A.

1984-01-01

331

Larval dermestid beetles feeding on nestling snail kites, wood storks, and great blue herons  

USGS Publications Warehouse

In recent years abdominal lesions attributable to larval dermestid beetles (Dermestes nidum) have appeared in nestling Snail (Everglade) Kites (Rostrhamus sociabilis), Wood Storks (Mycteria americana), and Great Blue Herons (Ardea herodias). Although it appears that most nestlings affected have survived, the degree of threat posed by dermestid larvae to various avian species is as yet unclear.

Snyder, N.F.R.; Ogden, J.C.; Bittner, J.D.; Grau, G.A.

1984-01-01

332

Characteristics of apple snail giant neurons capable of generating action potentials in sodium-free solutions  

Microsoft Academic Search

The ability of apple snail giant neurons to generate action potentials in solutions that lack sodium ions is associated with the input resistance of these neurons in such a way that the higher the input resistance is, the more pronounced is this ability. Neurons in which this ability is well expressed usually exhibit low resting potential values and a slow

N. T. Parkhomenko

1970-01-01

333

Identification of an estrogen receptor gene in the natural freshwater snail Bithynia tentaculata.  

PubMed

Mollusks have received increasing interest in ecotoxicological studies but so far the available scientific analyses of how their genes are affected by anthropogenic pollutants are scarce. The focus of this study is to identify an estrogen receptor (er) gene in the common prosobranch snail Bithynia tentaculata and to test a hypothesis that 17?-Ethinylestradiol (EE2) will modulate er gene expression after short-term exposure. We set up exposure experiments with a total of 144 snails, which were collected from a natural population in southern Sweden. Snails were exposed to either 10ng/L or 100ng/L EE2 during 24h and/or 72h. From the isolated B. tentaculata RNA we successfully identified and characterized a novel er gene and phylogenetic analyses strongly indicate that the Bithynia er gene is an ortholog to the human ER? (ESR1, NR3A1). We found a significant interaction between EE2-dose and exposure duration on the er's gene expression (Two-way ANOVA; p=0.04). We also found a significant difference in the gene expression of the er when comparing the control and 100ng/L treatment groups after 72h in female snails (One-way ANOVA; p=0.047). The results from this study should be useful for future field-related studies of estrogen receptors in natural populations of mollusks. PMID:24583164

Hultin, Cecilia L; Hallgren, Per; Persson, Anders; Hansson, Maria C

2014-04-25

334

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

E-print Network

Annotated Checklist of the Aquatic snails of the Mariana Islands, Micronesia by Alexander M Kerr. The first students of Marianas aquatic zoology were Jean-René Constant Quoy and Joseph Paul Gaimard, both fauna of the Marianas are from another Frenchman, Constant Récluz, who described four species occurring

Mcilwain, Jenny

335

Diet alters delayed selfing, inbreeding depression, and reproductive senescence in a freshwater snail  

PubMed Central

Reproductive success is a critical fitness attribute that is directly influenced by resource availability. Here, we investigate the effects of diet-based resource availability on three interrelated aspects of reproductive success: a change in mating system based on mate availability, consequent inbreeding depression, and the deterioration of reproductive efficiency with age (senescence). We employed a factorial experimental design using 22 full-sib families of the hermaphroditic freshwater snail Physa acuta to explore these interactions. Individual snails were reared in one of two mate-availability treatments (isolated [selfing] or occasionally paired [outcrossing]) and one of two diet treatments (boiled lettuce or Spirulina, an algae that is rich in protein, vitamins, and minerals). Spirulina-fed snails initiated reproduction at a 13% earlier age and 7% larger size than lettuce-fed snails. Spirulina also resulted in a 30% reduction in the time delay before selfing. Compared to lettuce, a diet of Spirulina increased inbreeding depression by 52% for egg hatching rate and 64% for posthatching juvenile survival. Furthermore, Spirulina led to a 15-fold increase in the rate of reproductive senescence compared with a diet of lettuce. These transgenerational, interactive effects of diet on inbreeding depression and reproductive senescence are discussed in the context of diet-induced phenotypic plasticity. PMID:25165532

Auld, Josh R; Henkel, John F

2014-01-01

336

Diet alters delayed selfing, inbreeding depression, and reproductive senescence in a freshwater snail.  

PubMed

Reproductive success is a critical fitness attribute that is directly influenced by resource availability. Here, we investigate the effects of diet-based resource availability on three interrelated aspects of reproductive success: a change in mating system based on mate availability, consequent inbreeding depression, and the deterioration of reproductive efficiency with age (senescence). We employed a factorial experimental design using 22 full-sib families of the hermaphroditic freshwater snail Physa acuta to explore these interactions. Individual snails were reared in one of two mate-availability treatments (isolated [selfing] or occasionally paired [outcrossing]) and one of two diet treatments (boiled lettuce or Spirulina, an algae that is rich in protein, vitamins, and minerals). Spirulina-fed snails initiated reproduction at a 13% earlier age and 7% larger size than lettuce-fed snails. Spirulina also resulted in a 30% reduction in the time delay before selfing. Compared to lettuce, a diet of Spirulina increased inbreeding depression by 52% for egg hatching rate and 64% for posthatching juvenile survival. Furthermore, Spirulina led to a 15-fold increase in the rate of reproductive senescence compared with a diet of lettuce. These transgenerational, interactive effects of diet on inbreeding depression and reproductive senescence are discussed in the context of diet-induced phenotypic plasticity. PMID:25165532

Auld, Josh R; Henkel, John F

2014-07-01

337

J Mammary Gland Biol Neoplasia . Author manuscript Snail family regulation and epithelial mesenchymal transitions in breast  

E-print Network

J Mammary Gland Biol Neoplasia . Author manuscript Page /1 12 Snail family regulation the mammary gland as cellular model. EMT: general characteristics, stages of EMT found and . Partial EMTin wound healing and mammary tubulogenesis ( ), and leads to an intermediate phenotype, retaining some2

Paris-Sud XI, Université de

338

Snail1-dependent control of embryonic stem cell pluripotency and lineage commitment  

PubMed Central

Embryonic stem cells (ESCs) exhibit the dual properties of self-renewal and pluripotency as well as the ability to undergo differentiation that gives rise to all three germ layers. Wnt family members can both promote ESC maintenance and trigger differentiation while also controlling the expression of Snail1, a zinc-finger transcriptional repressor. Snail1 has been linked to events ranging from cell cycle regulation and cell survival to epithelial–mesenchymal transition (EMT) and gastrulation, but its role in self-renewal, pluripotency or lineage commitment in ESCs remains undefined. Here we demonstrate using isogenic pairs of conditional knockout mouse ESCs, that Snail1 exerts Wnt- and EMT independent control over the stem cell transcriptome without affecting self-renewal or pluripotency-associated functions. By contrast, during ESC differentiation, an endogenous Wnt-mediated burst in Snail1 expression regulates neuroectodermal fate while playing a required role in epiblast stem cell exit and the consequent lineage fate decisions that define mesoderm commitment. PMID:24401905

Lin, Yongshun; Li, Xiao-Yan; Willis, Amanda L.; Liu, Chengyu; Chen, Guokai; Weiss, Stephen J.

2014-01-01

339

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

NASA Astrophysics Data System (ADS)

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

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

2013-12-01

340

Antioxidant defenses and metabolic depression. The hypothesis of preparation for oxidative stress in land snails  

Microsoft Academic Search

The roles of enzymatic antioxidant defenses in the natural tolerance of environmental stresses that impose changes in oxygen availability and oxygen consumption on animals is discussed with a particular focus on the biochemistry of estivation and metabolic depression in pulmonate land snails. Despite reduced oxygen consumption and PO2 during estivation, which should also mean reduced production of oxyradicals, the activities

Marcelo Hermes-Lima; Janet M. Storey; Kenneth B. Storey

1998-01-01

341

Chemical analysis of mucus from certain land snails under Egyptian conditions  

Microsoft Academic Search

The present investigation was carried out to study the chemical analysis of the mucus of three common land snails, Eobania vermiculata, Theba pisana and Monacha obstructa, and identification of the chemical compositions by using GC-MS. Results revealed that several variations in composition were observed between all species. Oxime, methoxy-phenyl and cyclotrisiloxane, hexamethyl were major components found that in three species,

A. A. A. Sallam; S. A. El-Massry; I. N. Nasr

2009-01-01

342

Effect of Population Density on Growth of Land Snail Helix aspersa maxima  

Microsoft Academic Search

The first few weeks of life are of great importance for the growth of snails. Breeders have to carefully handle this delicate and costly phase. The impact of population density increased with the number of animals and the duration of nursery. The highest tested densities did not have a negative effect on growth up to two weeks, after which a

A. Blanc; J. Attia

1992-01-01

343

Double labelling of neural grafts for identification of sites mediating growth in snails  

Microsoft Academic Search

Several parameters were studied in an experiment on intracerebral neural grafts in young snails (Helix aspersa aspersa) in which growth was blocked by removal of the mesocerebrum. The results demonstrate that transplantation of adult mesocerebrum neurons from another subspecies (H aspersa maxima) into the location of the ablated mesocerebrum in the brain of a young juvenile host, leads to functional

A Gomot

1997-01-01

344

Guanine and inosine nucleotides, nucleosides and oxypurines in snail muscles as potential biomarkers of fluoride toxicity.  

PubMed

The aim of the present study was to determine the toxicity of fluorides on energy metabolism in muscles of the Helix aspersa maxima snail. Qualitative and quantitative analysis of purine compounds was performed in slices of foot from mature snails with high-performance liquid chromatography. Fluoride concentrations were measured using an ion-selective electrode and gas chromatography. The results show that exposure to fluoride pollution was accompanied by a statistically significant increase in fluoride concentrations in soft tissues. This effect was already noticeable with the smallest fluoride dose. Accumulation was greatest in the shell. There is a significant and positive correlation between fluoride concentrations in foot muscles and guanine and inosine nucleotides or uridine content. The content of low-energy guanylate, inosylate and oxypurine in foot muscles significantly increased with rising dose of fluoride. The difference as compared with controls was significant only for the highest dose of fluoride. Interestingly, uric acid, the final product of purine catabolism, dominated quantitatively in the foot muscles of snails. In conclusion, increased low-energy guanylate and inosylate as well as decreased xanthine concentrations in snail muscle can be indicators of the toxic influence of fluoride on the organism. The measuring of fluoride accumulation in the shell is the most suitable bioindicator of fluoride pollution in the environment. PMID:18274260

Ra?, Monika E; Safranow, Krzysztof; Do?egowska, Barbara; Machoy, Zygmunt

2007-01-01

345

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

ERIC Educational Resources Information Center

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

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

2005-01-01

346

Studying Land Snails: Inquiry with K-W-L or Four Question Strategies.  

ERIC Educational Resources Information Center

Summarizes how a group of teachers prepared a series of elementary-level inquiry experiences that focused on the study of land snails. Recommends and describes the K-W-L and Four Question inquiry strategies for younger and older students respectively. (WRM)

Coleman, Pamela; Thiessen, Ronda; Wilson, Debbie; Arey, Beth; Barrow, Lloyd H.

1999-01-01

347

Angiotensin II contributes to diabetic renal dysfunction in rodents and humans via Notch1/Snail pathway.  

PubMed

In nondiabetic rat models of renal disease, angiotensin II (Ang II) perpetuates podocyte injury and promotes progression to end-stage kidney disease. Herein, we wanted to explore the role of Ang II in diabetic nephropathy by a translational approach spanning from in vitro to in vivo rat and human studies, and to dissect the intracellular pathways involved. In isolated perfused rat kidneys and in cultured human podocytes, Ang II down-regulated nephrin expression via Notch1 activation and nuclear translocation of Snail. Hairy enhancer of split-1 was a Notch1-downstream gene effector that activated Snail in cultured podocytes. In vitro changes of the Snail/nephrin axis were similar to those in renal biopsy specimens of Zucker diabetic fatty rats and patients with advanced diabetic nephropathy, and were normalized by pharmacological inhibition of the renin-angiotensin system. Collectively, the present studies provide evidence that Ang II plays a relevant role in perpetuating glomerular injury in experimental and human diabetic nephropathy via persistent activation of Notch1 and Snail signaling in podocytes, eventually resulting in down-regulation of nephrin expression, the integrity of which is crucial for the glomerular filtration barrier. PMID:23707238

Gagliardini, Elena; Perico, Norberto; Rizzo, Paola; Buelli, Simona; Longaretti, Lorena; Perico, Luca; Tomasoni, Susanna; Zoja, Carla; Macconi, Daniela; Morigi, Marina; Remuzzi, Giuseppe; Benigni, Ariela

2013-07-01

348

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

PubMed

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. PMID:22728924

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

2012-08-01

349

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

PubMed Central

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

Leicht, Katja; Jokela, Jukka; Seppälä, Otto

2013-01-01

350

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

NASA Astrophysics Data System (ADS)

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

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

2014-09-01

351

Down regulation of sodium channels in the central nervous system of hibernating snails.  

PubMed

Hibernation, as behavior, is an evolutionary mode of adaptation of animal species to unfavorable environmental conditions. It is generally characterized by suppressed metabolism, which also includes down regulation of the energy consuming ion-channel functioning. Experimental data regarding decreased ion-channel function are scarce. Therefore, our goal was to study the possible down regulation of voltage-gated sodium channel (NaV) subtypes in the neurons of hibernating snails. Our immunohistochemical experiments revealed that the expression of NaV1.8-like channels in the central nervous system was substantially down regulated in hibernating animals. In contrast to NaV1.8-like, the NaV1.9-like channels were present in neurons independently from hibernating and non-hibernating states. Our western blot data supported the immunohistochemical results according to which the band of the NaV1.8-like channel protein was less intensively labeled in the homogenate of the hibernating snails. The NaV1.9-like immunoreactivity was equally present both in hibernating and active snails. Micro-electrophysiological experiments show that in hibernating snails both NaV1.8- and NaV1.9-like currents are substantially decreased compared to that of the active snails. The contradictory electrophysiological and immunohistochemical or western blot data suggest that the molecular mechanisms of the "channel arrest" could be different in diverse NaV channel subtypes. Climate changes will affect temperature extremes and a question is how different species beyond their physiological tolerance will or able to adapt to changing environment. Hibernation is an important mode of adaptation to extreme climatic variations, and pursuant to this the present results may contribute to the study of the behavioral ecology. PMID:24769022

Kiss, T; Battonyai, I; Pirger, Z

2014-05-28

352

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

PubMed Central

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

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

2004-01-01

353

Malacological assessment and natural infestation of Biomphalaria straminea (Dunker, 1848) by Schistosoma mansoni (Sambon, 1907) And Chaetogaster limnaei (K. Von Baer, 1827) in an urban eutrophic watershed.  

PubMed

The objective of this study was to perform a malacological assessment at the Ibirité reservoir watershed in the metropolitan region of Belo Horizonte (Minas Gerais) and to evaluate the natural infestation rate of Biomphalaria straminea (Gastropoda: Planorbidae) by Schistosoma mansoni (Platyhelminthes: Trematoda) and Chaetogaster limnaei (Oligochaeta: Naididae). The samples were collected from July to August 2002. The B. straminea individuals collected were kept in the laboratory; the natural infestation rate by S. mansoni and C. limnaei was assessed weekly. The malacological assessment identified five mollusk species present in the Ibirité reservoir watershed: B. straminea, Physa marmorata, Lymnea sp., Melanoides tuberculatus, and Pomacea austrum. Laboratory observations showed that the B. straminea individuals were infected by C. limnaei rather than S. mansoni. Although there was no infection of B. straminea by S. mansoni, presence of B. straminea in itself merits close attention due to possible risk of human schistosomiasis by the local population. PMID:16097724

Callisto, M; Moreno, P; Gonçalves, J F; Ferreira, W R; Gomes, C L Z

2005-05-01

354

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

Federal Register 2010, 2011, 2012, 2013, 2014

...Snail, Los Osos, San Luis Obispo County...incidental take permit under the Endangered...community of Los Osos, San Luis Obispo County...portion of Los Osos, San Luis Obispo County...are requesting a permit for take of...

2011-07-15

355

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

NASA Technical Reports Server (NTRS)

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

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

2006-01-01

356

[Malacophagous aptitudes of some French Zonitidae snails and their advantage in biological control of Lymnaea (Galba) truncatula Müller (author's transl)].  

PubMed

Experimental study of malacophagous aptitudes of different species of french Zonitidea snails. Analysis of their possibilities of grouping with Zonitoides nitidus in order to get an association of complementary predators in biological control of Lymnaea truncatula. The experiences show that the numbers of surviving snails are next for the groups: Zonitoides-Oxychilus draparnaudi and Z.-Aegopinella. But Aegopinella migrates less from experimental areas. Proposition of a technique of biological control without environmental modification. PMID:931319

Rondelaud, D

1977-01-01

357

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

PubMed Central

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

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

2005-01-01

358

Recruitment of Glycosyl Hydrolase Proteins in a Cone Snail Venomous Arsenal: Further Insights into Biomolecular Features of Conus Venoms  

PubMed Central

Cone snail venoms are considered an untapped reservoir of extremely diverse peptides, named conopeptides, displaying a wide array of pharmacological activities. We report here for the first time, the presence of high molecular weight compounds that participate in the envenomation cocktail used by these marine snails. Using a combination of proteomic and transcriptomic approaches, we identified glycosyl hydrolase proteins, of the hyaluronidase type (Hyal), from the dissected and injectable venoms (“injectable venom” stands for the venom variety obtained by milking of the snails. This is in contrast to the “dissected venom”, which was obtained from dissected snails by extraction of the venom glands) of a fish-hunting cone snail, Conus consors (Pionoconus clade). The major Hyal isoform, Conohyal-Cn1, is expressed as a mixture of numerous glycosylated proteins in the 50 kDa molecular mass range, as observed in 2D gel and mass spectrometry analyses. Further proteomic analysis and venom duct mRNA sequencing allowed full sequence determination. Additionally, unambiguous segment location of at least three glycosylation sites could be determined, with glycans corresponding to multiple hexose (Hex) and N-acetylhexosamine (HexNAc) moieties. With respect to other known Hyals, Conohyal-Cn1 clearly belongs to the hydrolase-type of Hyals, with strictly conserved consensus catalytic donor and positioning residues. Potent biological activity of the native Conohyals could be confirmed in degrading hyaluronic acid. A similar Hyal sequence was also found in the venom duct transcriptome of C. adamsonii (Textilia clade), implying a possible widespread recruitment of this enzyme family in fish-hunting cone snail venoms. These results provide the first detailed Hyal sequence characterized from a cone snail venom, and to a larger extent in the Mollusca phylum, thus extending our knowledge on this protein family and its evolutionary selection in marine snail venoms. PMID:22412800

Violette, Aude; Leonardi, Adrijana; Piquemal, David; Terrat, Yves; Biass, Daniel; Dutertre, Sébastien; Noguier, Florian; Ducancel, Frédéric; Stöcklin, Reto; Križaj, Igor; Favreau, Philippe

2012-01-01

359

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

PubMed

Several recent studies have demonstrated that the freshwater pulmonate snail Lymnaea stagnalis is extremely sensitive to metals (Co, Ni, Pb) in chronic exposures. The objective of the current study was to evaluate the acute and chronic sensitivity of L. stagnalis to Cu and investigate the underlying mechanism(s) of toxic action. A 96-h LC50 of 31?g L(-1) Cu was estimated indicating L. stagnalis was moderately acutely sensitive to Cu relative to other aquatic organisms. However, in a 30-day chronic exposure using juvenile snails an EC20 of 1.8?g L(-1) Cu was estimated for snail growth making L. stagnalis the most sensitive organism tested to date for Cu. Hardness-based and BLM-based water quality criteria for Cu at the water quality conditions used in this study were 7.8 and 1.5?g L(-1), respectively, indicating L. stagnalis is significantly under-protected by hardness-based WQC. Investigations into the mechanism(s) of toxic action for Cu were conducted on young adult snails necessitating higher Cu exposures. Exposure to Cu at 12?g L(-1) resulted in no detectable effects on hemolymph osmolality, net Ca(2+) uptake, titratable acid excretion, or ammonia excretion. Exposure to 48?g L(-1) Cu was shown to significantly reduce (91%) net Ca(2+) uptake which is strongly correlated with shell deposition and corresponding snail growth. Snails exposed to 48?g L(-1) Cu also exhibited reduced ammonia excretion, a marked hemolymph acidosis, and a compensatory increase in titratable acid excretion. The reduction in net Ca(2+) uptake was hypothesized to be a secondary effect of Cu-induced inhibition of carbonic anhydrase, but no reduction in carbonic anhydrase activity was detected. Overall, it remains unclear whether inhibition of Ca(2+) uptake is a direct result of Cu exposure or, along with the other observed physiological effects, is secondary to an unidentified primary mode of toxic action. Given the hypersensitivity of L. stagnalis to Cu, further study into the mechanisms of action and effects of varying water chemistry on Cu toxicity is clearly warranted. PMID:21723419

Brix, Kevin V; Esbaugh, Andrew J; Grosell, Martin

2011-09-01

360

Assessment of whole effluent toxicity on aquatic snails: bioaccumulation of Cr, Zn, and Fe, and individual effects in bioassays.  

PubMed

We used a freshwater gastropod, Lymnaea palustris, in chronic bioassays to assess the toxicity of an industrial effluent containing high levels of metals, particularly Cr, Zn, and Fe. Adult snails were exposed for four weeks to different concentrations of effluent sampled at three successive treatment steps (crude effluent, effluent after physicochemical treatment, and after biological treatment). Dose-dependent responses reflecting exposure (metal bioaccumulation) and effects on survival, fecundity, and malondialdehyde production (a proxy for oxidative stress) were investigated. We found that Cr and Zn were accumulated in snail tissues, whereas Fe was regulated. Body concentrations of Cr and Zn decreased along the effluent-treatment gradient, particularly after the physicochemical treatment. For controls versus treatments, no effect on malondialdehyde production was detected. Significant effects were noted for fecundity. The number of eggs per individual decreased for snails exposed to 20, 30, and 40% concentrations of physicochemically treated effluent and for snails exposed to an 80% concentration of the biologically treated effluent. A hormetic effect on the number of eggs per individual was observed for snails exposed to 10 and 20% concentrations of the effluent that had been biologically treated. Deleterious effects of the effluent on L. palustris fecundity were not correlated with high internal concentrations of metals in the snails, suggesting that toxicity resulted from other factors. PMID:15683184

Coeurdassier, Michaël; de Vaufleury, Annette; Crini, Nadia; Scheifler, Renaud; Badot, Pierre-Marie

2005-01-01

361

The Snail Transcription Factor Regulates the Numbers of Neural Precursor Cells and Newborn Neurons throughout Mammalian Life  

PubMed Central

The Snail transcription factor regulates diverse aspects of stem cell biology in organisms ranging from Drosophila to mammals. Here we have asked whether it regulates the biology of neural precursor cells (NPCs) in the forebrain of postnatal and adult mice, taking advantage of a mouse containing a floxed Snail allele (Snailfl/fl mice). We show that when Snail is inducibly ablated in the embryonic cortex, this has long-term consequences for cortical organization. In particular, when Snailfl/fl mice are crossed to Nestin-cre mice that express Cre recombinase in embryonic neural precursors, this causes inducible ablation of Snail expression throughout the postnatal cortex. This loss of Snail causes a decrease in proliferation of neonatal cortical neural precursors and mislocalization and misspecification of cortical neurons. Moreover, these precursor phenotypes persist into adulthood. Adult neural precursor cell proliferation is decreased in the forebrain subventricular zone and in the hippocampal dentate gyrus, and this is coincident with a decrease in the number of adult-born olfactory and hippocampal neurons. Thus, Snail is a key regulator of the numbers of neural precursors and newborn neurons throughout life. PMID:25136812

Zander, Mark A.; Cancino, Gonzalo I.; Gridley, Thomas; Kaplan, David R.; Miller, Freda D.

2014-01-01

362

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

PubMed

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. PMID:22438932

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

363

Gut Bacterial Communities in the Giant Land Snail Achatina fulica and Their Modification by Sugarcane-Based Diet  

PubMed Central

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. PMID:22438932

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

364

Molluscicidal effects of neem (Azadirachta indica) extracts on edible tropical land snails.  

PubMed

The effects of 350, 500 and 700 mg kg(-1) of crude extracts of neem, Azadirachta indica A Juss, on edible tropical land snails Archachatina marginata and Limicolaria aurora (Jay) were determined and compared with control using pawpaw, Carica papaya L as bait. Responses were measured through normal feeding, cessation of food intake, cessation of crawling, mucus secretion, lack of response to mechanical stimuli (mortality) and decomposition. Results showed no effects on the controls or snails exposed to neem seed oil extract. Crude extracts of bark, root and leaf of neem at 500 and 700 mg kg(-1) produced mortality after exposure for 48 h for L aurora and 72 h for A marginata. PMID:14971686

Ebenso, Ime E

2004-02-01

365

Strategic ejaculation in simultaneously hermaphroditic land snails: more sperm into virgin mates  

PubMed Central

Background It has been theorised that sperm competition promotes the strategic usage of costly sperm. Although sperm competition is thought to be an important driving force of reproductive traits in simultaneous hermaphrodites as well as in species with separate sexes, empirical studies on strategic ejaculation in simultaneous hermaphrodites are scarce. Results In the present study, we tested whether the simultaneously hermaphroditic land snail Euhadra quaesita adjusts the number of sperm donated according to the condition of the mate and whether the pattern of strategic ejaculation is in line with previously suggested theories. We found that individuals donated much more sperm when they copulated with a virgin mate than when they copulated with a non-virgin. Conclusion The virgin-biased pattern of ejaculation matches the theoretical prediction and suggests that sperm competition significantly influence the reproductive traits of simultaneously hermaphroditic land snails. PMID:24304518

2013-01-01

366

Enrichment and Identification of Cellulolytic Bacteria from the Gastrointestinal Tract of Giant African Snail, Achatina fulica.  

PubMed

The cellulolytic bacterial community structure in gastrointestinal (GI) tract of Achatina fulica was studied using culture-independent and -dependent methods by enrichment in carboxymethyl cellulose (CMC). Culture-dependent method indicated that GI tract of snail was dominated by Enterobacteriaceae members. When tested for cellulase activities, all isolates obtained by culture-dependent method showed both or either of CMCase or avicelase activity. Isolate identified as Citrobacter freundii showed highest CMCase and medium avicelase activity. Sequencing of clones from the 16S rRNA gene clone library identified ten operational taxonomic units (OTUs), which were affiliated to Enterobacteriaceae of phylum Gammaproteobacteria. Of these ten OTUs, eight OTUs closely matched with Enterobacter and Klebsiella genera. The most abundant OTU allied to Klebsiella oxytoca accounted for 70 % of the total sequences. The members of Klebsiella and Enterobacter were observed by both methods indicating their dominance among the cellulolytic bacterial community in the GI tract of the snail. PMID:25432338

Pawar, Kiran D; Dar, Mudasir A; Rajput, Bharati P; Kulkarni, Girish J

2014-11-29

367

Predator-Prey Interactions between Shell-Boring Beetle Larvae and Rock-Dwelling Land Snails  

PubMed Central

Drilus beetle larvae (Coleoptera: Elateridae) are specialized predators of land snails. Here, we describe various aspects of the predator-prey interactions between multiple Drilus species attacking multiple Albinaria (Gastropoda: Clausiliidae) species in Greece. We observe that Drilus species may be facultative or obligate Albinaria-specialists. We map geographically varying predation rates in Crete, where on average 24% of empty shells carry fatal Drilus bore holes. We also provide first-hand observations and video-footage of prey entry and exit strategies of the Drilus larvae, and evaluate the potential mutual evolutionary impacts. We find limited evidence for an effect of shell features and snail behavioral traits on inter- and intra-specifically differing predation rates. We also find that Drilus predators adjust their predation behavior based on specific shell traits of the prey. In conclusion, we suggest that, with these baseline data, this interesting predator-prey system will be available for further, detailed more evolutionary ecology studies. PMID:24964101

Castillo Cajas, Ruth F.; van Moorsel, Coline H. M.; Kundrata, Robin; Welter-Schultes, Francisco W.; Giokas, Sinos; Schilthuizen, Menno

2014-01-01

368

Consequences of Physical Disturbance by Tadpoles and Snails on Chironomid Larvae  

PubMed Central

Indirect interactions among community members impact on organisms. The effects of two snails, banded pond snail, Bellamya bengalensis (Lamarck), and Red-rimmed melania, Melanoides tuberculata (Müller), and tadpoles of Asian common toad, Duttaphrynus melanostictus (Schneider), on nonbiting midge larvae, Chironomus striatipennis Kieffer, were observed in experimental microcosm. Decrease in tube number and tube length of midge larvae was observed compared to control condition due to introduction of selected above mentioned organisms. The direct effects of non-predator organisms on the midge larvae are due to physical disturbance that destroys their tubes. This may result in vulnerability of midge larvae to predators in the wild. So the community structure may be altered by indirect effects, where one or more species, through their direct disturbance, indirectly change the abundance of other species. PMID:24672384

Pal, Gargi; Aditya, Gautam; Hazra, Niladri

2014-01-01

369

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

PubMed Central

Abstract Using published records and original data from recent field work and revision of Iranian material of certain species deposited in the collections of the Natural History Museum Basel, the Zoological Museum Berlin, and Natural History Museum Vienna, a checklist of the freshwater gastropod fauna of Iran was compiled. This checklist contains 73 species from 34 genera and 14 families of freshwater snails; 27 of these species (37%) are endemic to Iran. Two new genera, Kaskakia and Sarkhia, and eight species, i.e., Bithynia forcarti, Bithynia starmuehlneri, Bithynia mazandaranensis, Pseudamnicola georgievi, Kaskakia khorrasanensis, Sarkhia sarabensis, Valvata nowsharensis and Acroloxus pseudolacustris are described as new to science; Ecrobia grimmi (Clessin & Dybowski, 1888), Heleobia dalmatica (Radoman, 1974) and Hippeutis complanatus (Linnaeus, 1758) are reported for the first time from Iran. Additional field work is highly desirable for a more appropriate evaluation of the extant freshwater snail biodiversity in Iran. PMID:22977349

Glöer, Peter; Peši?, Vladimir

2012-01-01

370

Waste yield, proximate and mineral composition of three different types of land snails found in Nigeria.  

PubMed

Some aspects of the chemical and anatomical weight composition of land snails in Nigeria were analysed with a view to assessing the waste yield, carcass yield and their nutritional evaluation on wet weight basis. Proximate analysis of Archachatina, Archatina and Limicolaria species was carried out on the carcass. Moisture and protein contents were high in all samples, fat and ash contents were generally low while crude fibre was not detected. The concentrations of iron, copper, zinc, manganese, sodium, calcium, magnesium, potassium and cobalt were determined in the carcass. Values of iron, calcium, magnesium, sodium and potassium were consistently high while both chromium and cobalt were not detected. Anatomical fractionation showed the shell to vary between 17.12 - 31.99%, carcass varied between 36.97 - 45.14% and the intestine varied between 18.80 - 22.74%. Snails interact with man in a variety of ways, the beneficial interactions are enumerated. PMID:8833175

Adeyeye, E I

1996-03-01

371

Comparison of the bioaccumulation capacities of copper and zinc in two snail subspecies (Helix).  

PubMed

Bioaccumulation analyses of copper and zinc were carried out in two snail subspecies (Helix aspersa aspersa and Helix aspersa maxima) after 3 months of controlled farming (out of ground) with foods of different formulations. The results reveal some clear interspecific differences in affinity toward copper and zinc. For the two metals considered, H. aspersa aspersa has a bioaccumulation capacity much greater than that of H. aspersa maxima, mainly in the foot for copper and in the viscera for zinc. After 3 months, the concentrations of copper in feet and viscera are much higher than those presented in the literature on field animals. The farming and the analysis methodologies permitted obtaining snails under standard condition and open the way to the development of rational protocols for ecotoxicological studies in a laboratory as well as in the field. PMID:9417849

Gomot, A; Pihan, F

1997-11-01

372

Factors controlling carbon isotopic composition of land snail shells estimated from lab culturing experiment  

NASA Astrophysics Data System (ADS)

Carbon isotopic composition (?13C) of land snail shell carbonate is widely applied in reconstructing the C3/C4 vegetation distribution of paleo-environment, which is considered to reflect variations of some environmental parameters [1][2][3]. Land snail shell carbon has three potential sources: diet, atmospheric CO2 and ingested carbonate (limestone) [4]. However, their relative contributions to shell carbonate have not been understood well yet [4][5][6][7][8]. More researches are necessary before we could apply this tool in paleo-environment reconstruction, especially inter-lab culturing experiment. A kind of land snail species, Acusta despecta sieboldiana, was collected at Yokohama, Japan and cultured under suitable environment to lay eggs. The second generations were growing up from eggs to adults around 6-12 months at the temperature of 20°, 25° and 30°, respectively. All of the snails at 25° and 30° and most of those at 20° were fed by cabbage (C3 plant) during their life span while others were fed by corn (C4 plant). To investigate the effect of ingested carbonate, some of them were fed by Ca3(PO4)2 powder while others were fed by CaCO3 powder. ?13C of shells were analyzed by an Isotope Ratio Mass Spectrometry (Thermo Finnigan MAT 253); ?13C of food and snail tissue were measured by a Cavity Ring-Down Spectroscopy (Picarro G1121-i). At the same time, ?13C of eggshell and new born snails were analyzed by a Continuous Flow Isotope Ratio Mass Spectrometry (GasBench II). We confirmed that diet, atmospheric CO2 and ingested limestone could be important sources controlling shell ?13C values. And the temperature could affect shell carbonate ?13C values, too. A simple but credible frame was raised to discuss the mechanism of how each possible source and environmental parameter could affect shell carbonate ?13C values based on previous works [4][6][8] and this study. According to this frame and some reasonable assumptions, we have estimated the contribution of different carbon sources for each snail individual: to cabbage (C3 plant) fed groups, the contributions of diet, atmospheric CO2 and ingested limestone vary in a range of 66~80%, 16~24% and 0~13%, respectively. And to corn (C4 plant) fed groups, because of the possible food stress (lower consumption ability of C4 plant), they vary in 56~64%, 18~20% and 16~26%, respectively. We will discuss how these results could be consistent to the observations, which suggests our calculations are suitable and believable. In addition, we will discuss the carbon isotope fractionation during egg laying and hatching of land snails, too. [1] Goodfriend, 1992, Quaternary Sciences Reviews. 11, 665-685 [2] Yanes et al. 2009. Geochimica et Cosmochimica Acta, 73, 4077-4099 [3] Yanes et al., 2013. Palaeogeography, Plaeoclimatology, Palaeoecology, 378, 91-102 [4] Goodfriend and Hood, 1983. Radiocarbon, 25, 810-830 [5] Goodfriend and Stipp, 1983. Geology, 11, 575-577 [6] Stott, 2002. Earth and Planetary Science Letters, 195, 249-259 [7] Metref et al., 2003. Earth and Planetary Science Letters, 211, 381-393 [8] Romaniello et al., 2008. Quaternary Geochronology, 3, 68-75

Zhang, Naizhong; Yamada, Keita; Yoshida, Naohiro

2014-05-01

373

Downregulation of SNAIL sensitizes hepatocellular carcinoma cells to TRAIL-induced apoptosis by regulating the NF-?B pathway.  

PubMed

Hepatocellular carcinoma (HCC) is the sixth most common cancer and the second most lethal cancer worldwide. Evidence has shown HCC cell resistance to TRAIL?mediated apoptosis. In a previous study, we verified that silencing SNAIL downregulated the growth of HCC cells. In addition, the mechanism of resistance to TRAIL in HCC cells was connected with the activation of nuclear factor-?B (NF-?B). Thus, it was hypothesized that the downregultaion of SNAIL sensitizes HCC cells to TRAIL-induced apoptosis by regulating the NF-?B pathway. In the present study, the most effective lentiviral vectors carrying shRNA against SNAIL were selected and adenoviral vectors harboring TRAIL were constructed. The expression of SNAIL and TRAIL was detected by quantitative PCR and western blotting. HCC cell viability and apoptosis were assessed using an MTT assay and the Hoechst test. To determine how to sensitize HCC cells to TRAIL-induced apoptosis after silencing SNAIL, p53 was assessed by western blot analysis. We also investigated the expression of Bcl-xL, cIAP2, survivin and Raf-1 protein using western blot analysis and the apoptotic degree of HuH-7 cells was detected using the Hoechst test following the suppression of each gene, which was a possible molecular mechanism to sensitive TRAIL-induced apoptosis through the downregulation of SNAIL in HCC cells. Silencing SNAIL resulted in increased apoptosis by enhancing sensitization to TRAIL in all the HCC cells. Additionally, p53 protein was upregulated in HuH-7 cells. Expression of Bcl-xL, cIAP2, survivin and Raf-1 was downregulated following silencing of SNAIL, while down-regulation of any of the proteins contributed to SNAIL suppression enhancing HCC cell sensitivity to TRAIL?induced apoptosis, with the exception of cIAP2. The results demonstrated that silencing SNAIL can sensitize TRAIL-induced apoptosis in HCC cells by upregulating p53 protein and by regulating related genes of the NF-?B pathway such as Bcl-xL, survivin and Raf-1. PMID:25607597

Wan, Zhaojun; Pan, Huazheng; Liu, Shihai; Zhu, Jingjuan; Qi, Weiwei; Fu, Kai; Zhao, Teng; Liang, Jun

2015-03-01

374

Evolution of host resistance to parasite infection in the snail–schistosome–human system  

Microsoft Academic Search

The evolutionary strategies that emerge within populations can be dictated by numerous factors, including interactions with\\u000a other species. In this paper, we explore the consequences of such a scenario using a host–parasite system of human concern.\\u000a By analyzing the dynamical behaviors of a mathematical model we investigate the evolutionary outcomes resulting from interactions\\u000a between Schistosoma mansoni and its snail and

Yiding Yang; Zhilan Feng; Dashun Xu; Gregory J. Sandland; Dennis J. Minchella

375

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

PubMed Central

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

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

2012-01-01

376

Metapopulation genetic structure and migration pathways in the land snail Helix aspersa : influence of landscape heterogeneity  

Microsoft Academic Search

The spatial genetic structuring of the land snail Helix aspersa was investigated for 32 colonies within an intensive agricultural area, the polders of the Bay of Mont-Saint-Michel (France). Given the habitat patchiness and environmental instability, the setting of H. aspersa colonies meets the broader view of a metapopulation structure. The identification of extrinsic barriers to migration and their impact on the

Jean-François Arnaud

2003-01-01

377

Invasive Species Fact Sheets: Carp, Snail, Aphid, Comb Jelly, Chocolate Vine  

NSDL National Science Digital Library

This resource from ATEEC provides a number of fact sheets on invasive species which may be printed out or used as presentation material. The species described here are the big head carp, the giant African snail, the balsam wooly aphid, the comb jelly and the chocolate vine. The lesson plan is available for download as a PDF; users must create a free, quick login with ATEEC to access the materials.

2013-06-17

378

Hormetic Effects of Heavy Metals in Aquatic Snails: Is a Little Bit of Pollution Good?  

Microsoft Academic Search

Hormesis is the term to describe a stimulatory effects associated with a low dose of a potentially toxic substance or stress.\\u000a We had anecdotal evidence of hormetic effects in some of our previous experiments concerning the influence of heavy metals\\u000a on aquatic snail growth and recruitment. We therefore repeated a version of an earlier experiment but this time we expanded

Hugh Lefcort; Zachary Freedman; Sherman House; Mathew Pendleton

2008-01-01

379

PROCESSES CONTRIBUTING TO METABOLIC DEPRESSION IN HEPATOPANCREAS CELLS FROM THE SNAIL HELIX ASPERSA  

Microsoft Academic Search

Cells isolated from the hepatopancreas of the land snail Helix aspersa strongly depress respiration both immediately in response to lowered PO• (oxygen conformation) and, in the longer term, during aestivation. These phenomena were analysed by dividing cellular respiration into non-mitochondrial and mitochondrial respiration using the mitochondrial poisons myxothiazol, antimycin and azide. Non-mitochondrial respiration accounted for a surprisingly large proportion, 65±5

T. BISHOP; M. D. BRAND

380

Land snails as a diet diversification proxy during the early upper palaeolithic in Europe.  

PubMed

Despite the ubiquity of terrestrial gastropods in the Late Pleistocene and Holocene archaeological record, it is still unknown when and how this type of invertebrate resource was incorporated into human diets. In this paper, we report the oldest evidence of land snail exploitation as a food resource in Europe dated to 31.3-26.9 ka yr cal BP from the recently discovered site of Cova de la Barriada (eastern Iberian Peninsula). Mono-specific accumulations of large Iberus alonensis land snails (Ferussac 1821) were found in three different archaeological levels in association with combustion structures, along with lithic and faunal assemblages. Using a new analytical protocol based on taphonomic, microX-Ray Diffractometer (DXR) and biometric analyses, we investigated the patterns of selection, consumption and accumulation of land snails at the site. The results display a strong mono-specific gathering of adult individuals, most of them older than 55 weeks, which were roasted in ambers of pine and juniper under 375°C. This case study uncovers new patterns of invertebrate exploitation during the Gravettian in southwestern Europe without known precedents in the Middle Palaeolithic nor the Aurignacian. In the Mediterranean context, such an early occurrence contrasts with the neighbouring areas of Morocco, France, Italy and the Balkans, where the systematic nutritional use of land snails appears approximately 10,000 years later during the Iberomaurisian and the Late Epigravettian. The appearance of this new subsistence activity in the eastern and southern regions of Spain was coeval to other demographically driven transformations in the archaeological record, suggesting different chronological patterns of resource intensification and diet broadening along the Upper Palaeolithic in the Mediterranean basin. PMID:25141047

Fernández-López de Pablo, Javier; Badal, Ernestina; Ferrer García, Carlos; Martínez-Ortí, Alberto; Sanchis Serra, Alfred

2014-01-01

381

Antipredatory Behavior as an Index of Heavy-Metal Pollution? A Test Using Snails and Caddisflies  

Microsoft Academic Search

.   The loss of behaviors that organisms use to avoid predation may serve as a sensitive indicator of pollution. We tested the\\u000a hypothesis that a correlation exists in the field between heavy metal levels and antipredator behaviors. We examined the antipredator\\u000a behavior of aquatic caddisfly larvae and snails at sites in the Coeur d'Alene basin of Northern Idaho which varied

H. Lefcort; E. Ammann; S. M. Eiger

2000-01-01

382

Diurnal variations in physiological activities in the garden snail, Cryptozona ligulata  

Microsoft Academic Search

Acetylcholinesterase (AChE) activity in the central nervous system and foot muscle in the garden snail,Cryptozona ligulata, was maximum at 20.00 h and minimum at 08.00 h during the 24 h period of the day. The cyclic variation in acetylcholine (ACh) was out of phase with that of AChE. In the body fluid, ACh content showed a rhythm with maximum at

G. Rajarami Reddy; T. Pavan Kumar; P. Murali Mohan; K. Sasira Babu

1978-01-01

383

Variation In Metabolic Cost of Embryonic Development of the Freshwater Snail, Phsya sp  

Microsoft Academic Search

Embryos of the freshwater snail Physa sp. complete their development within an egg capsule and hatch as juveniles. To estimate the energetic cost of development, oxygen consumption rates of egg masses were monitored from deposition to hatching. Oxygen consumption increased during development (r2=O.173, p\\u000aOriginally presented in the John Wesley Powell Student Research Conference - April 14, 2007 and used

Hall Andrew

2007-01-01

384

Oreohelix strigosa cooperi (Cooper’s Rocky Mountain Snail): A Technical Conservation Assessment  

Microsoft Academic Search

ACKNOWLEDGMENTS This assessment was prepared for the Rocky Mountain Region of the USDA Forest Service under contract number,53-82X9-3-0060. Special thanks to Kerry Burns of the Back Hills National Forest for providing GIS coverages of snail distribution and fire events. Gary Patton of the USFS was especially helpful in setting up the assessment format. Richard Vacirca of the USDA Forest Service

Tamara Anderson

385

Determination of digestive enzyme kinetics: a new method to define trophic niches in freshwater snails  

Microsoft Academic Search

Fluorogenic substrate analogues (MUF substrates) are very sensitive in detecting hydrolytic enzymes. This method was adapted\\u000a for the quantitative analysis of extracellular enzymes in snails and other animals. It was then used to determine cellobiase,\\u000a chitobiase, protease, esterase, phosphatase and lipase in the digestive tract of Radix \\u000a peregra and Bithynia \\u000a tentaculata. The method was sensitive enough to determine the complete

Heinz Brendelberger

1996-01-01

386

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

USGS Publications Warehouse

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

Riggs, A.C.

1984-01-01

387

Spawning and larval development of the black turban snail Tegula funebralis (Prosobranchia: Trochidae)  

Microsoft Academic Search

An understanding of spawning and larval development can be fundamental to interpreting the abundance, distribution, and population\\u000a structure of marine invertebrate taxa. Tegula funebralis (A. Adams, 1855), the black turban snail, has been the focus of numerous ecological studies on the Pacific coast of North\\u000a America. To date, there are only conflicting and anecdotal reports of spawning, and there is

A. L. Moran

1997-01-01

388

Comparison of the Bioaccumulation Capacities of Copper and Zinc in Two Snail Subspecies ( Helix)  

Microsoft Academic Search

Bioaccumulation analyses of copper and zinc were carried out in two snail subspecies (Helix aspersa aspersaandHelix aspersa maxima) after 3 months of controlled farming (out of ground) with foods of different formulations. The results reveal some clear interspecific differences in affinity toward copper and zinc. For the two metals considered,H. aspersa aspersahas a bioaccumulation capacity much greater than that ofH.

Annette Gomot; François Pihan

1997-01-01

389

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

Microsoft Academic Search

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

A. C. RIGGS

1984-01-01

390

Major Carbon14 Deficiency in Modern Snail Shells from Southern Nevada Springs  

Microsoft Academic Search

Carbon-14 contents as low as 3.3 ± 0.2 percent modern (apparent age, 27,000 years) measured from the shells of snails Melanoides tuberculatus living in artesian springs in southern Nevada are attributed to fixation of dissolved HCO3{}- with which the shells are in carbon isotope equilibrium. Recognition of the existence of such extreme deficiencies is necessary so that erroneous ages are

Alan C. Riggs

1984-01-01

391

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

SciTech Connect

Carbon-14 contents as low as 3.3 +/- 0.2% modern (apparent age, 27,000 years) measured from the shells of snails Melanoides tuberculatus living in artesian springs in southern Nevada are attributed to fixation of dissolved HCO/sub 3//sup -/ with which the shells are in carbon isotope equilibrium. Recognition of the existence of such extreme deficiencies is necessary so that erroneous ages are not attributed to fresh water biogenic carbonates. 2 figures, 1 table.

Riggs, A.C.

1984-04-06

392

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

PubMed

Carbon-14 contents as low as 3.3 +/- 0.2 percent modern (apparent age, 27,000 years) measured from the shells of snails Melanoides tuberculatus living in artesian springs in southern Nevada are attributed to fixation of dissolved HCO(3)(-) with which the shells are in carbon isotope equilibrium. Recognition of the existence of such extreme deficiencies is necessary so that erroneous ages are not attributed to freshwater biogenic carbonates. PMID:17783523

Riggs, A C

1984-04-01

393

Land Snails as a Diet Diversification Proxy during the Early Upper Palaeolithic in Europe  

PubMed Central

Despite the ubiquity of terrestrial gastropods in the Late Pleistocene and Holocene archaeological record, it is still unknown when and how this type of invertebrate resource was incorporated into human diets. In this paper, we report the oldest evidence of land snail exploitation as a food resource in Europe dated to 31.3-26.9 ka yr cal BP from the recently discovered site of Cova de la Barriada (eastern Iberian Peninsula). Mono-specific accumulations of large Iberus alonensis land snails (Ferussac 1821) were found in three different archaeological levels in association with combustion structures, along with lithic and faunal assemblages. Using a new analytical protocol based on taphonomic, microX-Ray Diffractometer (DXR) and biometric analyses, we investigated the patterns of selection, consumption and accumulation of land snails at the site. The results display a strong mono-specific gathering of adult individuals, most of them older than 55 weeks, which were roasted in ambers of pine and juniper under 375°C. This case study uncovers new patterns of invertebrate exploitation during the Gravettian in southwestern Europe without known precedents in the Middle Palaeolithic nor the Aurignacian. In the Mediterranean context, such an early occurrence contrasts with the neighbouring areas of Morocco, France, Italy and the Balkans, where the systematic nutritional use of land snails appears approximately 10,000 years later during the Iberomaurisian and the Late Epigravettian. The appearance of this new subsistence activity in the eastern and southern regions of Spain was coeval to other demographically driven transformations in the archaeological record, suggesting different chronological patterns of resource intensification and diet broadening along the Upper Palaeolithic in the Mediterranean basin. PMID:25141047

Fernández-López de Pablo, Javier; Badal, Ernestina; Ferrer García, Carlos; Martínez-Ortí, Alberto; Sanchis Serra, Alfred

2014-01-01

394

The effect of changes in habitat conditions on the movement of juvenile Snail Kites Rostrhamus sociabilis  

USGS Publications Warehouse

The degradation of habitats due to human activities is a major topic of interest for the conservation and management of wild populations. There is growing evidence that the Florida Everglades ecosystem continues to suffer from habitat degradation. After a period of recovery in the 1990s, the Snail Kite Rostrhamus sociabilis population suffered a substantial decline in 2001 and has not recovered since. Habitat degradation has been suggested as one of the primary reasons for this lack of recovery. As a consequence of the continued degradation of the Everglades, we hypothesized that this would have led to increased movement of juvenile Kites over time, as a consequence of the need to find more favourable habitat. We used multistate mark-recapture models to compare between-site movement probabilities of juvenile Snail Kites in the 1990s (1992–95; which corresponds to the period before the decline) and 2000s (2003–06; after the decline). Our analyses were based on an extensive radiotelemetry study (266 birds tracked monthly over the entire state of Florida for a total period of 6 years) and considered factors such as sex and age of marked individuals. There was evidence of increased movement of juvenile Snail Kites during the post-decline period from most of the wetland regions used historically by Kites. Higher movement rates may contribute to an increase in the probability of mortality of young individuals and could contribute to the observed declines.

Bowling, Andrea C.; Martin, Julien; Kitchens, Wiley M.

2012-01-01

395

Distribution and abundance of the Japanese snail, Viviparus japonicus, and associated macrobenthos in Sandusky Bay, Ohio  

USGS Publications Warehouse

A survey of the macrobenthos of Sandusky Bay, Lake Erie, in June, 1963, provided information on the abundance and distribution of the introduced Japanese snail, Viviparus japonicus, which has become a nuisance to commercial seine fishermen. The abundance and distribution varied considerably within the bay; at the time of the survey, most snails were found near the north-central shore. Environmental characteristics were nearly uniform and had no apparent effect on the distribution; concentrations in different areas at different times appeared to result from water movements induced by winds. The time of the study coincided with a period of reproduction; young-of-the-year snails were most abundant in areas where adults were most common. The frequency distributions of shell height and diameter suggested the presence of two age groups of adults in the population. Considerable natural mortality was seen, both at the time of the study and in other seasons. Only three other gastropods were observed in the bay; the most abundant was another viviparid, Campeloma decisum. Other mollusks present were four species of Sphaeriidae and 18 species of Unionidae. A summary of invertebrates found, other than the mollusks, is also presented.

Wolfert, David R.; Hiltunen, Jarl K.

1968-01-01

396

Inhibition of HSP27 blocks fibrosis development and EMT features by promoting Snail degradation.  

PubMed

Idiopathic pulmonary fibrosis (IPF) is a devastating disease characterized by myofibroblast proliferation. Transition of epithelial/mesothelial cells into myofibroblasts [epithelial-to-mesenchymal transition (EMT)] occurs under the influence of transforming growth factor (TGF)-?1, with Snail being a major transcription factor. We study here the role of the heat-shock protein HSP27 in fibrogenesis and EMT. In vitro, we have up- and down-modulated HSP27 expression in mesothelial and epithelial cell lines and studied the expression of different EMT markers induced by TGF-?1. In vivo, we inhibited HSP27 with the antisense oligonucleotide OGX-427 (in phase II clinical trials as anticancer agent) in our rat subpleural/pulmonary fibrosis models. We demonstrate that HSP27 is strongly expressed during the fibrotic process in patients with IPF and in different in vivo models. We showed that HSP27 binds to and stabilizes Snail and consequently induces EMT. Conversely, HSP27 knockdown leads to Snail proteasomal degradation, thus inhibiting TGF-?1-induced EMT. Inhibition of HSP27 with OGX-427 efficiently blocks EMT and fibrosis development. Controls in vivo were an empty adenovirus that did not induce fibrosis and a control antisense oligonucleotide. The present work opens the possibility of a new therapeutic use for HSP27 inhibitors against IPF, for which there is no conclusively effective treatment. PMID:23288928

Wettstein, Guillaume; Bellaye, Pierre-Simon; Kolb, Martin; Hammann, Arlette; Crestani, Bruno; Soler, Paul; Marchal-Somme, Joëlle; Hazoume, Adonis; Gauldie, Jack; Gunther, Andreas; Micheau, Olivier; Gleave, Martin; Camus, Philippe; Garrido, Carmen; Bonniaud, Philippe

2013-04-01

397

Nitric oxide is necessary for labilization of a consolidated context memory during reconsolidation in terrestrial snails.  

PubMed

Nitric oxide (NO) is known to be involved in associative memory formation. We investigated the influence of blocking NO function on the reconsolidation of context memory in terrestrial snails (Helix lucorum L.). After a 10 day session of electric shocks in one context only, context memory in snails was observed in test sessions as the significant difference of amplitudes of withdrawal responses to tactile stimuli in two different contexts. After a 1 day rest, a session of 'reminding' was performed, preceded by injection in different groups of the snails with either vehicle or combination of the protein synthesis blocker anisomycin (ANI) with one of the following drugs: the NO scavenger carboxy-PTIO, the NO-synthase inhibitors N-omega-nitro-L-arginin, nitroindazole and NG-nitro-L-arginine methyl ester hydrochloride, or the NO donor S-nitroso-N-acetyl-DL-penicillamine. Testing the context memory at different time intervals after the reminder under ANI injection showed that the context memory was impaired at 24 h and later, whereas the reminder under combined injection of ANI and each of the NO-synthase inhibitors used or the NO scavenger showed no impairment of long-term context memory. Injection of the NO donor S-nitroso-N-acetyl-DL-penicillamine with or without reminder had no effect on context memory. The results obtained demonstrated that NO is necessary for labilization of a consolidated context memory. PMID:24910164

Balaban, Pavel M; Roshchin, Matvey; Timoshenko, Alia K; Gainutdinov, Khalil L; Bogodvid, Tatiana K; Muranova, Lyudmila N; Zuzina, Alena B; Korshunova, Tatiana A

2014-09-01

398

Adaptive shell color plasticity during the early ontogeny of an intertidal keystone snail  

PubMed Central

We report a mechanism of crypsis present during the vulnerable early post-metamorphic ontogeny (?20 mm peristomal length) of the muricid snail Concholepas concholepas, a rocky shore keystone predator characteristic of the southeastern Pacific coast. In the field, we found a significant occurrence (>95%) of specimens bearing patterns of shell coloration (dark or light colored) that matched the background coloration provided by patches of Concholepas' most abundant prey (mussels or barnacles respectively). The variation in shell color was positively associated with the color of the most common prey (r = 0.99). In laboratory experiments, shell coloration of C. concholepas depended on the prey-substrate used to induce metamorphosis and for the post-metamorphic rearing. The snail shell color matched the color of the prey offered during rearing. Laboratory manipulation experiments, switching the prey during rearing, showed a corresponding change in snail shell color along the outermost shell edge. As individuals grew and became increasingly indistinguishable from the surrounding background, cryptic individuals had higher survival (71%) than the non cryptic ones (4%) when they were reared in the presence of the predatory crab Acanthocyclus hassleri. These results suggest that the evolution of shell color plasticity during the early ontogeny of C. concholepas, depends on the color of the more abundant of the consumed prey available in the natural habitat where settlement has taken place; this in turn has important consequences for their fitness and survivorship in the presence of visual predators. PMID:19805296

Manríquez, Patricio H.; Lagos, Nelson A.; Jara, María Elisa; Castilla, Juan Carlos

2009-01-01

399

WAVE3 promotes epithelial-mesenchymal transition of gastric cancer through upregulation of Snail.  

PubMed

WAVE3, an actin cytoskeleton remodeling protein overexpressed in many kinds of cancers, has been associated with a lot of metastatic diseases. However, the role and mechanisms of the high expression of WAVE3 in human gastric cancer has not been fully elucidated. Here we demonstrated that WAVE3 was expressed in all six kinds of gastric-cancer cell lines: BGC-823, SGC-7901, AGS, MGC803, MKN28 and MKN45. Furthermore, a correlation was found between aggressiveness of these cell lines and expression of WAVE3. Next, we investigated the role of WAVE3 in SGC-7901 cells and found that upregulating WAVE3 could promote the migration, invasion and proliferation of SGC-7901 cells in vitro. It has been reported that WAVE3 could induce cancer invasion and metastasis by participating epithelial-mesenchymal transition (EMT). However, the mechanisms are not entirely clear. In this study we showed that elevated WAVE3 levels could induce EMT in SGC-7901 cells by dampening the expression of E-cadherin while increasing the expression of vimentin. Elevated WAVE3 levels could also improve the expression of transcription factor Snail. In addition, downregulating Snail could particularly reduce EMT and the metastasis, invasion and proliferation activity in SGC-7901 cells elevated by overexpression of WAVE3. Taken together, we demonstrated that WAVE3 promoted gastric-cancer-cells migration and invasion by taking part in EMT via upregulation of Snail. WAVE3 could be a useful target for gastric-cancer prevention and therapy. PMID:25378074

Yue, Z; Feng, W; Xiangke, L; Liuxing, W; Qingxia, F; Jianbo, G

2014-12-01

400

Identification and characterization of a goose-type lysozyme from sewage snail Physa acuta.  

PubMed

Freshwater snail Physa acuta has been considered as an important invasive species and medical mollusc. Field investigation has shown that this snail could survive better than other snails in polluted water bodies. To understand the immune mechanisms of P. acuta, suppression subtractive hybridization hepatopancreas cDNA library has been constructed with bacterial challenge. In this study, a full-length cDNA of a novel goose-type lysozyme (PALysG) has been identified from P. acuta by EST and RACE technique. The conservative structure domains share high homology with other molluscan g-type lysozymes including the SLT domain, the substrate binding sites, the catalytic residues, three alpha-helices structures and six molluscan specific cysteines. Meanwhile, PALysG is the first record of goose-type lysozyme in Gastropoda. Real-time PCR indicated that PALysG mRNA had been expressed significantly at high levels in hepatopancreas for 8-48 h. PALysG recombinant protein displayed the lytic activity of g-type lysozyme with other organisms against Micrococcus lysodikicus. PMID:24882016

Guo, Yunhai; He, Hongxuan

2014-08-01

401

Evolution of separate predation- and defence-evoked venoms in carnivorous cone snails  

PubMed Central

Venomous animals are thought to inject the same combination of toxins for both predation and defence, presumably exploiting conserved target pharmacology across prey and predators. Remarkably, cone snails can rapidly switch between distinct venoms in response to predatory or defensive stimuli. Here, we show that the defence-evoked venom of Conus geographus contains high levels of paralytic toxins that potently block neuromuscular receptors, consistent with its lethal effects on humans. In contrast, C. geographus predation-evoked venom contains prey-specific toxins mostly inactive at human targets. Predation- and defence-evoked venoms originate from the distal and proximal regions of the venom duct, respectively, explaining how different stimuli can generate two distinct venoms. A specialized defensive envenomation strategy is widely evolved across worm, mollusk and fish-hunting cone snails. We propose that defensive toxins, originally evolved in ancestral worm-hunting cone snails to protect against cephalopod and fish predation, have been repurposed in predatory venoms to facilitate diversification to fish and mollusk diets. PMID:24662800

Dutertre, Sébastien; Jin, Ai-Hua; Vetter, Irina; Hamilton, Brett; Sunagar, Kartik; Lavergne, Vincent; Dutertre, Valentin; Fry, Bryan G.; Antunes, Agostinho; Venter, Deon J.; Alewood, Paul F.; Lewis, Richard J.

2014-01-01

402

Adjustment of metabolite composition in the haemolymph to seasonal variations in the land snail Helix pomatia.  

PubMed

In temperate regions, land snails are subjected to subzero temperatures in winter and hot temperatures often associated to drought in summer. The response to these environmental factors is usually a state of inactivity, hibernation and aestivation, respectively, in a temperature and humidity buffered refuge, accompanied by physiological adjustments to resist cold or heat stress. We investigated how environmental factors in the microhabitat and body condition influence the metabolite composition of haemolymph of the endangered species Helix pomatia. We used UPLC and GC-MS techniques and analyzed annual biochemical variations in a multivariate model. Hibernation and activity months differed in metabolite composition. Snails used photoperiod as cue for seasonal climatic variations to initiate a physiological state and were also highly sensitive to temperature variations, therefore constantly adjusting their physiological processes. Galactose levels gave evidence for the persistence of metabolic activity with energy expenditure during hibernation and for high reproductive activity in June. Triglycerides accumulated prior to hibernation might act as cryoprotectants or energy reserves. During the last month of hibernation snails activated physiological processes related to arousal. During activity, protein metabolism was reflected by high amino acid level. An exceptional aestivation period was observed in April giving evidence for heat stress responses, like the protection of cells from dehydration by polyols and saccharides, the membrane stabilization by cholesterol and enhanced metabolism using the anaerobic succinic acid pathway to sustain costly stress responses. In conclusion, physiological adjustments to environmental variations in Helix pomatia involve water loss regulation, cryoprotectant or heatprotectant accumulation. PMID:21136264

Nicolai, Annegret; Filser, Juliane; Lenz, Roman; Bertrand, Carole; Charrier, Maryvonne

2011-05-01

403

FOXM1 Promotes Lung Adenocarcinoma Invasion and Metastasis by Upregulating SNAIL  

PubMed Central

The forkhead box M1 (FOXM1) transcription factor is one of the key genes inducing tumor invasion and metastasis by an unknown mechanism. In this study, we set out to investigate the effects of FOXM1 overexpression on metastatic human lung adenocarcinoma and the underlying mechanism. FOXM1 expression was analyzed in 78 frozen lung adenocarcinoma tissue samples using an Affymetrix microarray and a 155-paraffin-embedded lung adenocarcinoma tissue microarray with immunohistochemical detection. FOXM1 was found to be overexpressed in lung adenocarcinoma, particularly in metastatic patients, compared to non-metastatic patients. Knockdown of FOXM1 by a specific siRNA significantly suppressed EMT progression, migration and invasion of lung adenocarcinoma cells in vitro, and tumor growth and metastasis in vivo, whereas restored expression of FOXM1 had the opposite effect. FOXM1 binds directly to the SNAIL promoter through two specific binding sites and constitutively transactivates it. Collectively, our findings indicate that FOXM1 may play an important role in advancing lung adenocarcinoma progression. Aberrant FOXM1 expression directly and constitutively activates SNAIL, thereby promoting lung adenocarcinoma metastasis. Inhibition of FOXM1-SNAIL signaling may present an ideal target for future treatment. PMID:25561901

Wei, Ping; Zhang, Nu; Wang, Yiqin; Li, Dawei; Wang, Lisha; Sun, Xiangjie; Shen, Chen; Yang, Yusi; Zhou, Xiaoyan; Du, Xiang

2015-01-01

404

FOXM1 Promotes Lung Adenocarcinoma Invasion and Metastasis by Upregulating SNAIL.  

PubMed

The forkhead box M1 (FOXM1) transcription factor is one of the key genes inducing tumor invasion and metastasis by an unknown mechanism. In this study, we set out to investigate the effects of FOXM1 overexpression on metastatic human lung adenocarcinoma and the underlying mechanism. FOXM1 expression was analyzed in 78 frozen lung adenocarcinoma tissue samples using an Affymetrix microarray and a 155-paraffin-embedded lung adenocarcinoma tissue microarray with immunohistochemical detection. FOXM1 was found to be overexpressed in lung adenocarcinoma, particularly in metastatic patients, compared to non-metastatic patients. Knockdown of FOXM1 by a specific siRNA significantly suppressed EMT progression, migration and invasion of lung adenocarcinoma cells in vitro, and tumor growth and metastasis in vivo, whereas restored expression of FOXM1 had the opposite effect. FOXM1 binds directly to the SNAIL promoter through two specific binding sites and constitutively transactivates it. Collectively, our findings indicate that FOXM1 may play an important role in advancing lung adenocarcinoma progression. Aberrant FOXM1 expression directly and constitutively activates SNAIL, thereby promoting lung adenocarcinoma metastasis. Inhibition of FOXM1-SNAIL signaling may present an ideal target for future treatment. PMID:25561901

Wei, Ping; Zhang, Nu; Wang, Yiqin; Li, Dawei; Wang, Lisha; Sun, Xiangjie; Shen, Chen; Yang, Yusi; Zhou, Xiaoyan; Du, Xiang

2015-01-01

405

Mucus secretion by the freshwater snail Lymnaea stagnalis limits aluminum concentrations of the aqueous environment  

SciTech Connect

Extracellular mucopolysaccharide (EPS) is a significant component in many waters. Its role in the cycling and mobilization of metals is unclear. In vitro studies were conducted to examine the influence of EPS, secreted by the freshwater pond snail, Lymnaea stagnalis, on soluble water Al concentrations at near-neutral pH. Snails maintained in aerated water of known ion content and added aluminum reduced Al in solution as compared to controls. Although snails accumulated Al into soft tissue, this only accounted for a small percentage of the total reduction. The remaining Al was recovered following acidification of the water. This observation was attributed to pedal EPS secreted by L. stagnalis which is chiefly insoluble and substrate bound. The Al that remained in solution was more labile, possibly due to the influence of soluble EPS. Further experiments with isolated EPS, confirmed that this poorly soluble film binds and reduces Al in solution. The influence of EPS on the solution chemistry and bioavailability of Al and possibly other metals may be important in natural waters.

Jugdaohsingh, R.; Thompson, R.P.H.; Powell, J.J. [St. Thomas Hospital, London (United Kingdom)] [St. Thomas Hospital, London (United Kingdom); Campbell, M.M.; Mccrohan, C.R.; White, K.N. [Univ. of Manchester (United Kingdom). School of Biological Sciences] [Univ. of Manchester (United Kingdom). School of Biological Sciences

1998-09-01

406

Nutritional status of four species of giant land snails in Nigeria.  

PubMed

Four species of African giant land snails (Archachatina marginata (ovum) Pfeiffer, Archachatina marginata (saturalis) Philippi, Achatina achatina and Limicolaria spp.) were assessed for their proximate and mineral compositions aimed at establishing their nutritive values on wet weight basis. Analysis of muscle revealed that composition of crude protein varied from 18.66%+/-0.57% in Limicolaria spp. and 20.56%+/-0.05% in Archachatina marginata (ovum) Pfeiffer; moisture content was 76.56%+/-0.04% in Archachatina marginata (ovum) Pfeiffer and 78.68%+/-0.68% in Limicolaria spp. and ash was 1.34%+/-0.02% in Achatina achatina and 1.44%+/-0.01% in Archachatina marginata (ovum) Pfeiffer. These values were statistically different from each other (P<0.05). Carbohydrate and fat content were generally low. Crude fibre was not detected in any of the species. The concentrations of zinc, iron, manganese, magnesium, calcium, phosphorus, sulphur, potassium and sodium in the flesh of the snails were determined. Values of iron, magnesium, calcium, phosphorus, potassium and sodium were consistently high while cobalt, copper and lead were not detected. Snails complement the required trace and minor elements needed for proper growth and development in human being, so it is recommended for regular consumption. PMID:16909467

Fagbuaro, O; Oso, J A; Edward, J B; Ogunleye, R F

2006-09-01

407

Nutritional status of four species of giant land snails in Nigeria  

PubMed Central

Four species of African giant land snails (Archachatina marginata (ovum) Pfeiffer, Archachatina marginata (saturalis) Philippi, Achatina achatina and Limicolaria spp.) were assessed for their proximate and mineral compositions aimed at establishing their nutritive values on wet weight basis. Analysis of muscle revealed that composition of crude protein varied from 18.66%±0.57% in Limicolaria spp. and 20.56%±0.05% in Archachatina marginata (ovum) Pfeiffer; moisture content was 76.56%±0.04% in Archachatina marginata (ovum) Pfeiffer and 78.68%±0.68% in Limicolaria spp. and ash was 1.34%±0.02% in Achatina achatina and 1.44%±0.01% in Archachatina marginata (ovum) Pfeiffer. These values were statistically different from each other (P<0.05). Carbohydrate and fat content were generally low. Crude fibre was not detected in any of the species. The concentrations of zinc, iron, manganese, magnesium, calcium, phosphorus, sulphur, potassium and sodium in the flesh of the snails were determined. Values of iron, magnesium, calcium, phosphorus, potassium and sodium were consistently high while cobalt, copper and lead were not detected. Snails complement the required trace and minor elements needed for proper growth and development in human being, so it is recommended for regular consumption. PMID:16909467

Fagbuaro, O.; Oso, J.A.; Edward, J.B.; Ogunleye, R.F.

2006-01-01

408

Dose-dependent effects of cadmium on the growth of snails in toxicity bioassays.  

PubMed

The effects on survival and growth of exposure to cadmium (Cd) in the food were analyzed in juvenile snails (age one month, mean weight 1 g) of the two subspecies Helix aspersa aspersa (H.a.a.) and H. aspersa maxima (H.a.m.). The experiments lasted for four weeks and the animals were fed with special snail food containing 0-, 50-, 100-, 200-, 400-, and 800 microg Cd/g of dry food. No significant adverse effect (NOEC) was noted at 50 microg/g for three weeks. A negative effect of Cd on growth was noted from 100 to 800 microg/g and plotting the growth coefficient variation against the Cd concentration led to an estimate of the EC75 at day 14 of 370 microg/g in H.a.a. and 470 microg/g in H.a.m. and at day 28 of 290 microg/g in H.a.a. and 330 microg/g in H.a.m. Juvenile snails are thus a suitable material for use as bioindicators in the assay of contamination of food. PMID:9294251

Gomot, A

1997-08-01

409

Sexual selection on land snail shell ornamentation: a hypothesis that may explain shell diversity  

PubMed Central

Background Many groups of land snails show great interspecific diversity in shell ornamentation, which may include spines on the shell and flanges on the aperture. Such structures have been explained as camouflage or defence, but the possibility that they might be under sexual selection has not previously been explored. Presentation of the hypothesis The hypothesis that is presented consists of two parts. First, that shell ornamentation is the result of sexual selection. Second, that such sexual selection has caused the divergence in shell shape in different species. Testing the hypothesis The first part of the hypothesis may be tested by searching for sexual dimorphism in shell ornamentation in gonochoristic snails, by searching for increased variance in shell ornamentation relative to other shell traits, and by mate choice experiments using individuals with experimentally enhanced ornamentation. The second part of the hypothesis may be tested by comparing sister groups and correlating shell diversity with degree of polygamy. Implications of the hypothesis If the hypothesis were true, it would provide an explanation for the many cases of allopatric evolutionary radiation in snails, where shell diversity cannot be related to any niche differentiation or environmental differences. PMID:12791170

Schilthuizen, Menno

2003-01-01

410

Pharmaceutical bioaccumulation by periphyton and snails in an effluent-dependent stream during an extreme drought.  

PubMed

Increasing evidence indicates that pharmaceutical bioaccumulate in fish collected downstream from municipal wastewater effluent discharges. However, studies of pharmaceutical bioaccumulation by other aquatic organisms, including primary producers (e.g., periphyton) and grazers (e.g., snails), are lacking in wadeable streams. Here, we examined environmental occurrence and bioaccumulation of a range of pharmaceuticals and other contaminants of emerging concern in surface water, a common snail (Planorbid sp.) and periphyton from an effluent-dependent stream in central Texas, USA, during a historic drought, because such limited dilution and instream flows may represent worst-case exposure scenarios for aquatic life to pharmaceuticals. Water and tissue samples were liquid-liquid extracted and analyzed by liquid chromatography-tandem mass spectrometry (LC-MS/MS) with electrospray ionization. Target analytes included 21 pharmaceuticals across multiple drug classes and 2 pharmacologically active metabolites. Several pharmaceuticals were detected at up to 4.7?gkg(-1) in periphyton and up to 42?gkg(-1) in Planorbid sp. We then identified limitations of several bioconcentration factor and bioaccumulation factor models, developed for other invertebrates, to assist interpretation of such field results. Observations from the present study suggest that waterborne exposure to pharmaceuticals may be more important than dietary exposure for snails. PMID:25261960

Du, Bowen; Haddad, Samuel P; Scott, W Casan; Chambliss, C Kevin; Brooks, Bryan W

2015-01-01

411

Effect of light intensity on Opisthorchis viverrini cercarial shedding levels from Bithynia snails--a preliminary study.  

PubMed

Opisthorchis viverrini requires Bithynia snails as the first intermediate host and cyprinid fish as the second intermediate host. Very low natural infection rates have been reported in Bithynia snails, but very high rates have been found in cyprinid fish in the same endemic region. This study investigated the effect of light intensity, the most important stimulus, on the quantity of O. viverrini cercariae shed from naturally infected Bithynia (Digoniostoma) siamensis goniomphalos snails. Snails were evaluated for cercariae output every hour after exposure to various light intensities for a total period of 7h. The same infected snail was tested under different intensities of light: in the dark, and at 1000, 3000 and 5000 lx. The data showed that under exposure to 1000 and 3000 lx of light, the average percentage and number of cercariae released were higher than that exposed to 5000 lx during the first 2h of the experiment. In contrast, under higher illumination (5000 lx) a longer time (6h) was required to stimulate the peak emergence of cercariae. Darkness was not able to induce O. viverrini cercariae emergence. Among the three intensities of light, exposure at 1000 lx induced the highest average number of released cercariae per snail and the highest percentage of cercarial emergence within the first 2h (125, 54.86%), followed by exposure at 3000 lx (69, 25.58%) and 5000 lx (12, 7.78%). The results suggest that the light intensity of 1000 lx for 2h would be optimal for O. viverrini cercarial shedding from naturally infected B. (D.) siamensis goniomphalos snails. PMID:21872679

Kaewkes, Sasithorn; Kaewkes, Wanlop; Boonmars, Thidarut; Sripa, Banchob

2012-03-01

412

Snail bioaccumulation of triclocarban, triclosan, and methyltriclosan in a North Texas, USA, stream affected by wastewater treatment plant runoff.  

PubMed

Grazing by freshwater snails promotes nutrient turnover in algal communities. Grazed algal compartments may include antimicrobial agents and metabolites, such as triclocarban (TCC), triclosan (TCS), and methyltriclosan (MTCS), which are incompletely removed by wastewater treatment plant (WWTP) processing. The present study quantifies snail bioaccumulation factors (BAFs) for TCC, TCS, and MTCS at the outfall of Pecan Creek (TX, USA), the receiving stream for the city of Denton (TX, USA) WWTP. Helisoma trivolvis (Say) is ubiquitous and thrives under standard laboratory conditions, leading to its choice for this bioaccumulation study in conjunction with Cladophora spp. Along with providing substrate for epiphytic growth, Cladophora spp. provide a source of food and shelter for H. trivolvis. After being caged for two weeks, algae and snails were collected from the WWTP outfall, along with water-column samples, and analyzed by isotope dilution gas chromatography-mass spectrometry for TCS and MTCS and by liquid chromatography-mass spectrometry for TCC. Algal and snail samples were analyzed before exposure and found to be below practical quantitation limits for all antimicrobial agents. Triclocarban, TCS, and MTCS in water samples were at low-ppt concentrations (40-200 ng/L). Triclocarban, TCS, and MTCS were elevated to low-ppb concentrations (50-300 ng/g fresh wt) in caged snail samples and elevated to low-ppb concentrations (50-400 ng/g fresh wt) in caged algal samples. Resulting snail and algal BAFs were approximately three orders of magnitude, which supports rapid bioaccumulation among algae and adult caged snails at this receiving stream outfall. The results further support TCC, TCS, and MTCS as good candidate marker compounds for evaluation of environmental distribution of trace WWTP contaminants. PMID:18380516

Coogan, Melinda A; La Point, Thomas W

2008-08-01

413

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

PubMed Central

Studies of plant invasions rarely address impacts on molluscs. By comparing pairs of invaded and corresponding uninvaded plots in 96 sites in floodplain forests, we examined effects of four invasive alien plants (Impatiens glandulifera, Fallopia japonica, F. sachalinensis, and F.×bohemica) in the Czech Republic on communities of land snails. The richness and abundance of living land snail species were recorded separately for all species, rare species listed on the national Red List, and small species with shell size below 5 mm. The significant impacts ranged from 16–48% reduction in snail species numbers, and 29–90% reduction in abundance. Small species were especially prone to reduction in species richness by all four invasive plant taxa. Rare snails were also negatively impacted by all plant invaders, both in terms of species richness or abundance. Overall, the impacts on snails were invader-specific, differing among plant taxa. The strong effect of I. glandulifera could be related to the post-invasion decrease in abundance of tall nitrophilous native plant species that are a nutrient-rich food source for snails in riparian habitats. Fallopia sachalinensis had the strongest negative impact of the three knotweeds, which reflects differences in their canopy structure, microhabitat humidity and litter decomposition. The ranking of Fallopia taxa according to the strength of impacts on snail communities differs from ranking by their invasiveness, known from previous studies. This indicates that invasiveness does not simply translate to impacts of invasion and needs to be borne in mind by conservation and management authorities. PMID:25238059

Horá?ková, Jitka; Ju?i?ková, Lucie; Šizling, Arnošt L.; Pyšek, Petr

2014-01-01

414

Sewage sludge application in a plantation: effects on trace metal transfer in soil-plant-snail continuum.  

PubMed

We studied the potential bioaccumulation of Cu, Zn, Pb and Cd by the snail Cantareus aspersus and evaluated the risk of leaching after application of sewage sludge to forest plantation ecosystems. Sewage sludge was applied to the soil surface at two loading rates (0, and 6 tons ha(-1) in dry matter) without incorporation into the soil so as to identify the sources of trace metal contamination in soil and plants and to evaluate effects on snail growth. The results indicated a snail mortality rate of less than 1% during the experiment, while their dry weight decreased significantly (<0.001) in all treatment modalities. Thus, snails showed no acute toxicity symptoms after soil amendment with sewage sludge over the exposure period considered. Additions of sewage sludge led to higher levels of trace metals in forest litter compared to control subplots, but similar trace metal concentrations were observed in sampling plants. Bioaccumulation study demonstrated that Zn had not accumulated in snails compared to Cu which accumulated only after 28 days of exposure to amended subplots. However, Pb and Cd contents in snails increased significantly after 14 and 28 days of exposure in both the control and amended subplots. At the last sampling date, in comparison to controls the Cd increase was higher in snails exposed to amended subplots. Thus, sludge spread therefore appears to be responsible for the observed bioaccumulation for Cu and Cd after 28days of exposure. Concerning Pb accumulation, the results from litter-soil-plant compartments suggest that soil is this metal's best transfer source. PMID:25262293

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

2015-01-01

415

Identification of optimum scopes of environmental factors for snails using spatial analysis techniques in Dongting Lake Region, China  

PubMed Central

Background Owing to the harmfulness and seriousness of Schistosomiasis japonica in China, the control and prevention of S. japonica transmission are imperative. As the unique intermediate host of this disease, Oncomelania hupensis plays an important role in the transmission. It has been reported that the snail population in Qiangliang Lake district, Dongting Lake Region has been naturally declining and is slowly becoming extinct. Considering the changes of environmental factors that may cause this phenomenon, we try to explore the relationship between circumstance elements and snails, and then search for the possible optimum scopes of environmental factors for snails. Methods Moisture content of soil, pH, temperature of soil and elevation were collected by corresponding apparatus in the study sites. The LISA statistic and GWR model were used to analyze the association between factors and mean snail density, and the values in high-high clustered areas and low-low clustered areas were extracted to find out the possible optimum ranges of these elements for snails. Results A total of 8,589 snail specimens were collected from 397 sampling sites in the study field. Besides the mean snail density, three environmental factors including water content, pH and temperature had high spatial autocorrelation. The spatial clustering suggested that the possible optimum scopes of moisture content, pH, temperature of the soil and elevation were 58.70 to 68.93%, 6.80 to 7.80, 22.73 to 24.23°C and 23.50 to 25.97 m, respectively. Moreover, the GWR model showed that the possible optimum ranges of these four factors were 36.58 to 61.08%, 6.541 to 6.89, 24.30 to 25.70°C and 23.50 to 29.44 m, respectively. Conclusion The results indicated the association between snails and environmental factors was not linear but U-shaped. Considering the results of two analysis methods, the possible optimum scopes of moisture content, pH, temperature of the soil and elevation were 58.70% to 68.93%, 6.6 to 7.0, 22.73°C to 24.23°C, and 23.5 m to 26.0 m, respectively. The findings in this research will help in making an effective strategy to control snails and provide a method to analyze other factors. PMID:24886456

2014-01-01

416

Effects of dietary calcium on growth and oviposition of the African land snail Limicolaria flammea (Pulmonata: Achatinidae).  

PubMed

In an attempt to elucidate the role of calcium in the life of the edible Achatinid snail, Limicolaria flammea (Miller) I investigated short and long term effects of calcium added to the food. The short term experiments lasted for 18, 30 and 32 weeks respectively, while the long term experiment to determine life time utilization of calcium carbonate lasted for 15 months. In the short term experiments, hatchlings were divided into densities of one, ten and 50 snails. In the 10 snail group, there was a positive correlation between calcium provision, body weight (t test, p < 0.01; r = 0.96, p < 0.0001) and shell length (t test, p < 0.01; r = 0.96, p < 0.00001). There was also a positive correlation between increase in shell length and availability of calcium in the 1 snail group (t test, p< 0.01; r = 0.99, p < 0.00001). In the 50-snail group, the correlation was positive for shell length of the snails (t test, p < 0.05; r = 0.99, p < 0.0001) and body weight (t-test, p < 0.05; r = 99, p < 0.00001). Mortality was very high in the snails deprived of calcium and they did not produce eggs. In the long term experiment, there were three feeding peaks in L. flammea. In the first feeding peak, amount of food and calcium ingested by the snails increased in the first three months of life. The second feeding peak occurred at six months of age, while the last occurred at 10 months of age. The amount of calcium ingested during the second peak decreased gradually in the 4th and 5th month. The amount of calcium ingested was lowest during the 3rd feeding peak. The period of highest weight gained by the snails was between the 1st and 6th month and then dropped at between six and 12 months of age which corresponds to the period of egg production. There were also three peaks of egg production; the first was between six and eight months (535 eggs), the second at between 10 and 11 months (350 eggs) and the third at 13 to 14 months (310 eggs) respectively. PMID:18624247

Egonmwan, Rosemary I

2008-03-01

417

Comparative evaluation of haemagglutination potential of haemolymph from two species of giant African land snails (Archachatina marginata and Achatina achatina).  

PubMed

A comparative study was conducted to evaluate haemagglutination potential in the haemolymph of two species of giant African land snails (Archachatina marginata and Achatina achatina). Three liveweight groups of snails (<100 g, 101-150 g and >150 g) were used with 4 replicates per liveweight per species for haemagglutination assay (HA). The effect of aestivation on haemagglutination potential was also evaluated. Erythrocytes (2%) from cattle, sheep, goat and chicken were used for HA assay. Results showed that agglutinin-like substances that agglutinate erythrocytes of sheep, goat, cattle and chicken were present in the haemolymph of the two species of giant African land snails. Effect of species was found to be significant (P < 0.001) on haemagglutination titre. Haemolymph of A. marginata, had higher haemagglutination titre than that of A. achatina across the three liveweight groups used in this study. Snail liveweight had no significant effect (P > 0.05) on agglutinin content of the haemolymph in both species. Agglutination level depended on the source of erythrocyte used. Sheep erythrocyte recorded the highest haemagglutination titre, followed by goat, cattle, and chicken in that order. To our knowledge, this is the first evidence that Giant African land snails (GALS) haemolymph contain agglutinins as previously reported for Helix species. This evidence may be the basis for its survivability in the wild and thus establish the use of GALS for African herbal medicinal applications. PMID:24657726

Abiona, John Adesanya; Akinduti, Paul Akinniyi; Oyekunle, Mufutao Atanda; Osinowo, Olusegun Ayodeji; Onagbesan, A Okanlawon Mohammed

2014-05-01

418

Chemical extractions and predicted free ion activities fail to estimate metal transfer from soil to field land snails.  

PubMed

This study investigates the relevance of several soil chemical extractions (calcium chloride, acetic acid, citric acid and a four-step sequential procedure) and predicted free metal ion activities in the soil solution to characterise the transfer of trace metals (Cd, Pb, and Zn