Showing papers on "Biomphalaria alexandrina published in 2006"

Synthesis and Molluscicidal Activity of New Cinnoline and Pyrano[2,3‐c]pyrazole Derivatives.

Abstract: 2-(3-Hydroxy-5,5-dimethylcyclohexylidene)malononitrile 5 undergoes an azo coupling reaction with aryldiazonium salts to afford 3-amino-2-aryl-6,6-dimethyl-8-oxo-2,6,7,8-tetrahydrocinnoline-4-carbonitriles 7. Upon reflux in acetic acid, these compounds were acetylated to give the cinnoline derivatives 9. The pyrazolones 10a, b react with 3-furfurylidene- and 3-thienylidene-malononitrile derivatives 11a, b to afford the pyrano[2,3-c]pyrazole derivatives 13a-d. These newly synthesized compounds show generally a moderate molluscicidal activity to Biomphalaria alexandrina snails.

Molluscicidal activity and new flavonoids from Egyptian Iris germanica L. (var. alba).

Abstract: The molluscicidal activity of leaf and rhizome extracts of Iris germanica L. (var. alba) against Biomphalaria alexandrina snails was evaluated and the rhizome extracts were found to be the most potent. Activity-guided fractionation revealed that the chloroform extract showed the highest molluscicidal activity (LC90 = 1.26 mg/l) among the tested extracts of the rhizomes. Fraction B prepared from the chloroform extract was the most potent molluscicide (LC90 = 0.96 mg/l) in addition, it showed a significant heart rate reduction in the snail after a 6- to 24-h exposure period. It also displayed a significant level of cercaricidal potential in a time-concentration relationship pattern. Chromatographic fractionation and purification of fraction B resulted in the isolation of two novel compounds: 5,2'-dihydroxy-3-methoxy-6,7-methylenedioxyflavone and 5,7,2'-trihydroxy-6-methoxyflavanone. Their structures were established by one- and two-dimensional NMR methods and mass spectrometry.

Identification of a genetic marker associated with the resistance to Schistosoma mansoni infection using random amplified polymorphic DNA analysis

Abstract: In schistosomiasis, the host/parasite interaction remains not completely understood. Many questions related to the susceptibility of snails to infection by respective trematode still remain unanswered. The control of schistosomiasis requires a good understanding of the host/parasite association. In this work, the susceptibility/resistance to Schistosoma mansoni infection within Biomphalaria alexandrina snails were studied starting one month post infection and continuing thereafter weekly up to 10 weeks after miracidia exposure. Genetic variations between susceptible and resistant strains to Schistosoma infection within B. alexandrina snails using random amplified polymorphic DNA analysis technique were also carried out. The results showed that 39.8% of the examined field snails were resistant, while 60.2% of these snails showed high infection rates.In the resistant genotype snails, OPA-02 primer produced a major low molecular weight marker 430 bp. Among the two snail strains there were interpopulational variations, while the individual specimens from the same snail strain, either susceptible or resistant, record semi-identical genetic bands. Also, the resistant character was ascendant in contrast to a decline in the susceptibility of snails from one generation to the next.

Molluscicidal effect of three monoterpenes oils on schistosomiasis and fascioliasis vector snails in Egypt.

Abstract: Thymol, Linalool and Eugenol showed considerable molluscicidal effect against Biomphalaria alexandrina, Bulinus truncatus and Lymnneae natalensis. The thymol was the potent one at least LC50 and LC90) followed by euganol then linalool. L. natalensis were more sensitive to these compounds followed by B. truncatus and then B. alexandrina. The LC50 & LC90) of thymol were 22 and 34 ppm against B. alexaldrina, 20 and 30 ppm for B. truncatuts and 18 and 29 ppm for L. nalalensis. These values were higher with Eugenol, 28 and 48 ppm for B. alexuadrina, 24 and 44 ppm for B. truncatus and 22 and 40 ppm for L. natalensis. Linalool showed highest values of LCs5 and LC90 against B. alexandrina, 34 and 56 ppm, against B. truncatus 30 and 52 ppm and for L. natalensis 28 and 48 ppm, respectively. Maintaining of B. alexandrina at LC10 of Thymol for one week induced an inhibitory effect in the level of some enzymes (AchE, SDH). It led to increase in the activity of other enzymes (ACP, ALP & G-6-PD). Acetylcholine-sterase activity (AchE) of treated B. alexandrina was significantly reduced by 45.9% when compared to control. The results showed a significant decrease in succinate dehydrogenase activity (SDH) by 46.4% together with a concomitant increase in glucose-6-phosphate dehydrogenase activity level (G-6-PD) by 47.5% in comparison with control. The activities of acid phosphatase and alkaline phosphatase enzymes were found to be higher in the treated snails than in control ones. The percentage increases were 47.2% & 73.2% respectively. The results also showed an elevation in the hemolymph glucose content of treated snails by 51.9% while the tissue glycogen content was reduced by 48.1%. The infection of B. alexandrina with S. mansoni miracidia was greatly reduced by thymol LC10 (sublethal dose). The infection rate reduction was 43.1%. The treated snails' prepatent period was prolonged (34.2 +/- 3.3 days) compared to control (28.4 +/- 1.2 days). A highly significant reduction of total cercarial production per snail occurred in experimental snails as compared to control.

Effect of the plant Cupressus macro-carpa (Cupressacea) on some haematolo-gical and biochemical parameters of Biomphalaria alexandrina snails.

Abstract: The dry powder of the plant aereal part; Cupressus macro-carpa (Cupressacea) was tested against Biomphalaria alexandrina. LC50 & LC90 values were 59.5 & 98.8 ppm, respec-tively. Exposure of B. alexandrina to sublethal concentrations (LC0, LC10 & LC25) of C. macrocarpa for three weeks signi-ficantly decreased the number of circulating hemocytes. The magnitude of reduction was increased with increasing of the tested concentration. The main type of cell in the hemolymph of B. alexandrina was the granulocyte (71.8%), followed by large round cells or hyalinocytes (19.0%) and small round cells or undifferentiate cells (9.2%). The percentage of different hemocyte categories was changed in treated snails. In snails maintained at LC25, showed significantly higher percentages of small round cells than controls, 56.2% & 9.2% respectively. Maintainence of B. alexandrina in sublethal concentrations for three weeks significantly reduced protein & hemoglobin content in the hemolymph. Reduction in enzyme activities occurred in the hemolymph and tissues of treated snails. The enzymes were pyruvate kinase (PK), lactat dehydrogenase (LDH), hexokinase (HK) and phosphoenol pyruvate carboxy kinase (PEPCK) which are very important in metabolism of the protein and carbohydrate. The infectivity of Schistosoma mansoni miracidia was greatly reduced by exposure to the sublethal concentrations (LC0, LC10 & LC25) of Cupressus. Infection rate of B. alexandrina reached to 54.5%, 37.5% & 16.7%, respectively compared to control (81.25%). Duration of cercarial shedding and the total periodic cercarial production/snail showed significant reduction while the parasite incubation period was significantly longer (p<0.05).

Synthesis of furo-salicylanilides and their heterocyclic derivatives with anticipated molluscicidal activity.

Abstract: The synthesis of new furo-salicylanilides and their heterocyclic derivatives is described. Twenty-three compounds were screened for their molluscicidal activity against Biomphalaria alexandrina snails, the intermediate host of Schistosoma mansoni. Five of the tested compounds showed no activity, while eighteen compounds showed strong to moderate activity using bayluscide as a reference.

Molluscicidal effect of fenitrothion and anilofos on Lymnaea natalensis and Biomphalaria alexandrina snails and on the free larval stages of Schistosoma mansoni.

Abstract: Psticides; fenitrothion and anilofos (aniloguard) were testd as molluscicides against Lymnaea natalensis and Biomplhalaria alexandrina. The LC10 & LC90 of fenitrothion was 0.12 & 0.21 ppm for L. nalalensis and 0.17 & .26 ppm for B. alexandrina, respectively. The LC50 & LC90 anilofos was 2.61 & 6.47 ppm for Lymnaea and 3.07 & 8.6 ppm for Biomphalaria. The effect of sublethal concentrations (LC0, LC5 & C10) of Feni-rothion on B. alexandrina growth rate, eggs hatchability and on free larval stages of Schistosonma mansoni (miracidia & cerca-riae) were studied. The results obtained showed that sublethal concentrations of fenitrothion caused reduction in growth rate of B. alexandrina and reduction in the hatchibility of snails eggs. The mortality rates of miracidia and cercariae were elevated by increasing both the concentrations of fenitrothion and the time of exposure. The results showed that fenitrothion was more toxic to the free larval stages of S. mansoni than to their snails. The results showed a significant reduction in total protein of treated snails when compared with controls in haemolymph while there was an increase of protein contents of the tissue. The AlkP enzyme activity was slightly increased in the haemolymph of experimental groups than the control and in the tissues the values were significantly higher when compared with control. ALT enzyme activity in haemolymph of experimental groups was higher than controls while its activity in tissue was lower. AST enzyme activity was higher in haemolymph and tissue of experimental groups than in controls.

The molluscicidal activity of some plant extracts against biomphalaria alexandrina snails

Abstract: The present work evaluates the molluscicidal activities of certain plant extracts (water suspension, Cold water, Boiled water, methanol, ethanol, acetone and chloroform extract) against Biomphalaria alexandrina. Preliminary screening tests conducted on 10 plant species that belong to 9 different families showed that the higher potency was recorded for Agave celsii, Ammi visnaga and Chenopodium ambrosioices. Also, exposure of B. alexandrina snails to plant extracts led to a significant reduction in the survival and in the growth rates as well as in their infection with Schistosoma mansoni miracidia. The results obtained also revealed that the glucose concentration increased in haemolymph, while soft tissue glycogen and protein contents were decreased. The activities of Hexokinase, pyruvatekinase and lactate dehydrogenase were also significantly reduced in response to treatment, while adenosine triphosphatase (ATPase) activity of the tissue of the snails was significantly increased.

Influence of certain fertilizers on the activity of some molluscicides against Biomphalaria alexandrina and Lymnaea natalensis snails.

Abstract: Effect of the fertilizers (ammonium nitrate, potassium sulphate and urea) on molluscicidal activity of the molluscicides (copper sulphate, niclosamide & mollutox) against B. alexandrina and L. natalensis was investigated. The molluscicides were more potant than fertilizers. Snails were exposed for 24 hr to a fertilizers using LC0 (1/10 & LC50) then, to molluscicides. Pre-exposure to potassium sulphate caused a synergistic action with copper sulphate, niclosamide and mollutox on L. natalen-sis. Pre-exposure to urea caused an additive effect with niclo-samide and mollutox against L. natalensis and B. alexandrina respectively. Pre-exposure to ammonium nitrate caused an additive action to niclosamide on L. natalensis. Snails were exposed for 24hr to one molluscicide, then exposed to fertilizers, showed that pre-exposure to niclosamide or mollutox caused an additive effect with ammonium nitrate and potassium sulphate. Pre-exposure to mollutox caused an additive effect with urea on the two snails' sp. juvenile or adult B. alexandrina were ex-posed to LC0 of molluscicide-fertilizer mixture, showed that urea when mixed with each molluscicides showed greatly reduced on the growth rate percent (0.00), survival rate and snail fecundity. Molluscicides and fertilizers mixed at different ratios of LC (40:10, 30:20, 25:25, 20:30 & 10:40), the toxicity of the mixtures caused antagonistic effect on adult B. alexandrina, but a mixture of niclosamide-ammonium nitrate caused a potent effect (synergism or additive) except at ratio 20:30 which showed an antagonism on L. natalensis. Mixtures of copper sulphatepotassium sulphate (10:40), niclosamide-potassium sulphate (20:30), mollutox-ammonium nitrate (25:25) revealed an additive effect on L. natalensis.

Ultrastructural study on the effect of a plant molluscicide (solanum elaeagnifoljum) on the digestive and hermaphrodite glands of biomphalaria alexandrina

Abstract: U examination was applied to study the effect of short' (4 days) and long (10 days) exposures to sublethal concentration (1 ppm ) of ethanol extract of Solarium elaeagnifolium seeds (S. etaeag. ) (Family: Solanecae) on the digestive gland and hermaphrodite gland of infected and uninfected the pulmonate snail Biomphalaria alexandrina. Ultrastructural studies of the above two glands of infected snails illustrated remarkable cytologicai changes due to the infection with marked increase in the cytoplasmic vacuolation that almost occupied the whole cell of the digestive gland, The ultrastructural changes in the digestive and hermaphrodite gland cells due to exposure of snails to ethanol extract of the candidate plant showed degeneration in the nucleus, nucleolus and mitochondria with abnormal Golgi complex as well as in glycogen digestion. INTRODUCTION Schistosomiasis is one of the serious parasitic diseases which attack. many people in tropical and subtropical regions of the world causing serious losses in health and economy. In Egypt, the disease stands on the top of the public health problems and its impact on the health and economy is tremendous. Thus a considerable attention has been focused on its control by various means of which the control of the intermediate host snails of the parasite seems to be most possible if properly handled. 2 Abdalla M Ibrahim et ah Biomphalaria alexandrina ( Ehrenberg) is known to be the pulmonate species that acts as the intermediate host of Schistosoma mansoni in Egypt. The high cost and toxicity of synthetic molluscicides, used for the control of intermediate snail hosts of parasitic diseases, resulted in renewing the interest in plant molluscicides (Massoud and Habib,2003). The screening of local plants for their molluscicidal activity has received increasing attention by many authors (Tantawy et aL9 2000; Bakiy et aL, 2002). Extracts of plants in the genus Solarium (Solanaceae) showed significant mulluscicidal activity against some planorbid snails, (Bekkouch et aly 2000 ; Siiva et a/.,2005). Some general studies do exist about the ultrastructure of the digestive gland of certain molluscs, the most comprehensive of which were published by Walker(1970) and Pol(1971). On the electron microscopic level, Meuleman(1972) elucidated the changes induced in the digestive gland of south African strains of B. pfefferi as a result of infection with Schistosoma mansoni. Chen et al (2004) studied the ultrastructural changes induced in the hepatopancreas of. the gastropod Haliotis diversicolor as a result of ulcerate disease. The ultrastructural effects of extracts from Tetrapleura teiraptera (Taub.) and Bayluside on the digestive gland of B. glabrata were investigated by Bode et al (1996). The hepatopancreas and reproductive system in normal Oncomelania hupensis snails and in snails after treatment with seed extracts of Camellia sinensis were ultrastructurally examined by Song et al (1997). The present work aimed to study the effect of S. elaeagnifolium on infected and uninfected B. alexandrina as indicated by its action on the fine structure of both digestive and hermaphrodite glands. MATERMLS AND METHODS Solanum elaeagnifolium (Cav.) (Family: Solanaceae) was collected from north east Sainai, near El-Arish city. 250 grams of unripe seeds of Solanum elaeagnifolium were exhaustively extracted with 95% ethanol at room ^mperature. The extract was evaporated to dryness under vacuum. From the crude extract, a stock solution was prepared. B. alexandrina snails ( noninfected and infected with S. mansoni ) were obtained from Theodor Bilharz Research Institute, Imbaba, Giza, Egypt. ULTRASTRUCTURAL STUDY ON THE EFFECT OF 3 A PLANT MOLLUSCICIDE ON B. ALEXANDRINA Experimental desigmlnfected (shedding cercaria) and uninfected B. alexandrina snails(5-6 weeks old) were treated with bubiethql concentration (lppm) of ethanol extract of Solarium elaeagnifolium, Sonx of them were exposed to molluscicidal solution for 4 days and then recovered for 1 week. Others were exposed for 10 days continuously to themoliuscicide. Snails were then dissected to obtain the digestive and hermaphrodite glands to be prepared for ultrathin section examinationsExperimental conditions: During the experiments, snails were maintained at constant conditions of temperature (26°c ± 2°c) and artificial illumination (11 hours/day). Electron microscopy: 1 mm of both the digestive gland and the hermaphrodite gland of both infected and uninfected snails were primary fixed in 2% gluteraldehyde in sodium cacodylate buffer (0.1 (j. ,PH 7.4) for two hours at 4°c and then post fixed in 1% buffer osmium tetroxide for two hours at 4°c. The samples were dehydrated in acetone and embedded for 12 hours in Epon resin (812) (Luft, 1961). Ultrathin sections were cut and then mounted on copper grids, stained with uranyle acetate and lead citrate, and examined with Jeal JEM 100 S transmission electron microscope. RESULTS The digestive gland: The digestive gland of Biomphalaria alexandrina consists of two main types of cells, the digestive and secretory cells. The digestive cells: The electron microscope examination of uninfected and infected snails has revealed the presence of long, dense microvilli along the apical areas of the plasma membranes of the digestive cells (Fig. I). It also shows scattered cilia along thetuminal surface of these cells, each containing an axial filament complex of the conventional 9+2 configuration. The microvilli, as the cilia, are bounded by apical extensions from the plasma membranes of the cells. The ground cytoplasm of such cells contains a granular endoplasmic reticulum, mitochondria and occasionally Golgi complex. Also the digestive cells possess numerous digestive vacuoles of variable size (Fig. 1). The nuclei of the digestive cells occupy the basal regions, each containing a conspicuous nucleolus. The secretory cells: 4 Abdalla M. Ibrahim et al In the secretory cells of the digestive gland, the nucleus is situated in the broad basal part of the cell. At the ultrastructural level, the nucleolus appears to consist of a dense central part, surrounded by a less compact outer zone. The chromatin occurs mainly as clumps which lie scattered through the nucleoplasm and against the nuclear envelope. Outgrowths of the outer membrane of the nuclear envelope are continuous with cisternae of granular endoplasmic reticulum (GER). The extensive GER which is composed of tubules and numerous, mainly parallel, cisternae accounts for the strong basophilia of the cytoplasm, while a well develop Golgi apparatus is located in the supranuclear region. Mitochondria often occur in close association with the secretion granules (Fig. 2). A high density of mitochondria, longer and thicker than those of the digestive cells and occasionally containing small electron-dense granules are found apical to the nucleus and over the basal cell membrane. The degeneration of the secretory cells starts with the appearance of few vacuoles containing yellow bodies in the cytoplasm. Their ultrastructural examination show that these vacuoles contain acid phosphatase and so are probably autophagosomes and recognized as degenerating cell organelles. ■ The digestive cells of infected snails displayed various signs of degeneration. The endoplasmic-reticulum became distinctly swollen and the mitochondria were reduced in number, more elongated and accumulated (Fig.3). The cytoplasmic vacuoles became abundant without any apparent inclusions, causing change in the nucleus shape, the secretory cells of digestive gland displayed numerous vacuoles also (Figs.4&5). Ultrastructural changes of digestive gland after treatment with 1 ppm ethanol extract-.of & elaeagnifolium for 4 days and recovery for 1 week, showed phosphohydrolase reactions producing an accumulation of dense stain precipitate, surrounding the nucleus which started to separate from the cytoplasm presenting .a narrow suture (Fig. 6), However, the chromatin clumps were decreased and scattered against the nuclear envelope.. This is probably an.autophagosome indicating a sign of cell orgaiielies degeneration, No more damage in the digestive gland cell content was observed after short exposure to the molluscicide except a high density of mitochondria which appeared cloudy because the density of the matrix decreased and the inner membrane became displaced and collapsed onto ULTRASTRUCTURAL STUDY ON THE EFFECT OF 5 A PLANT MOLLUSCICIDE ON B. ALEXANDRINA a limited area of the external membrane. Some of these mitochondria appeared swollen. At daughter sporocyst, the mitochondria revealed more damage ana part of them became degenerated and seemed vacuolated mitochondria (Fig. 7). The same pathogenesis was observed in the digestive gland of snails exposed to 1 ppm ethanol extract of 5. elaeagnifolium for 10 days (Fig.8). However, more degeneration occurred in the endoplasmic reticulum accompanied with neumerous vacuoles. The hermaphrodite gland: Under light microscope, the sperm of B. alexandrina appears as an extremely long thin filament with a slightly enlarged anterior tip. At higher magnifications, a small corkscrew-shaped head is discernible ; provided with an acrosome and followed by a helicoidal middle piece which ends in a short tail (Fig. 9). The helix of the middle piece appears double in most of its length but is single near the tail. The inner organization of the sperm components was better understood by the ultrathin section examination (Fig, 10). Oogonia and mature ova are relatively little and therefore rarely seen. The hermaphrodite gland appeared more affected than the digestive gland, especially in snails exposed to 1 ppm of ethanol extract of S. elaeagnifolium for 10 days. After short exposure period (4 days) and 1 week recovery to 1 ppm of the plant molluscicide, the plasma membrane of the sperms appeared as dense fibrous bands (Fig. 11). Glycogen granules in the normal sperms appear as dense granu

Efficiency of melia azadrach fruit water extract on biomphalaria alxandrina snails

Abstract: Efficiency of Melia azadrach fruit water extract (F.W.E.) was studied on Biomphalaria alexandrina non-infected and Schistosoma mansoni-infected snails. The LC50 and LC90 values of F.W.E. were 161.4 and 372.6 ppm, respectively for non-infected adult snails after 72 hrs of exposure. Miracidicidal and cercaricidal activity of M. azadrach F.W.E. were studied. The LC50 and LC90 were 875.12, 13370.1 ppm, respectively for miracidia and 140.13, 561.4 ppm, respectively for cercariae after 60 minutes of exposure. Over 4 weeks of exposure, the tested concentration of M. azadrach F.W.E. (80 ppm) caused a significantly acceleration of the egg laying capacity of infected and non-infected snails. The treatment of infected snails led to reduction in prepatent period and significant increased the cercarial output. It also increased total hemocytes count of non-infected snails during the period from 72 hrs to 4th week while the total hemocytes count was significantly reduced in treated-infected snails during four weeks post infection. Moreover, the plant extract induced alterations of differential hemocytes count of infected and non - infected snails. Granular hemocytes were observed to be the major responsive hemocytes in treated snails. Also, some morphological abnormalities were observed in hemocytes during the first 3 days and ended by the 1st week. Elctrophoretic analysis of total plasma protein using SDS-PAGE electrophoresis revealed qualitative and quantitative differences with occasional appearance and absence of certain bands. The results indicated that treatment led to significant reduction of total plasma protein content.

Synthesis of Furo-salicylanilides and Their Heterocyclic Derivatives with Anticipated Molluscicidal Activity.

Abstract: The synthesis of new furo-salicylanilides and their heterocyclic derivatives is described. Twenty-three compounds were screened for their molluscicidal activity against Biomphalaria alexandrina snails, the intermediate host of Schistosoma mansoni. Five of the tested compounds showed no activity, while eighteen compounds showed strong to moderate activity using bayluscide as a reference.

Toxicity of commiphora molmol (myrrh) water suspension to some non-target aquatic organisms and its molluscicidal and biological activities on bulinus truncatus and biomphalaria alexandrina (mollusca, gastropoda) -

Abstract: The molluscicidal activity of Commiphora molmol (myrrh) water suspension showed that Bulinus truncatus snails were found to be about 3 times more susceptible than Biomphalaria alexandrina snails. The 24-hour LC50 values recorded were 46.4 and 145.8 ppm, respectively. There was a significant negative correlation between LC values and exposure periods. The present study is yet the first attempt to investigate the toxicity of C. molmol aquous suspension (in vitro) against non-target aquatic organisms coexisting with vector snails in their habitat. The obtained results revealed that the plant water suspension was more toxic at the molluscicidal levels to the crustaceans Daphnia sp, Cypris sp, Cyclops sp. , Cardina nilotica and the fish Gambuzia affinis at a concentration of 50 ppm (in average) after 48 hr of exposure. Culex larvae were more tolerant to the plant suspension than other organisms. Chronic effects of sublethal concentrations of C. molmol water suspension on some biological parameters of B. truncatus snails showed a significant decrease in food consumption and egg production of snails. At the sublethal concentration of LC50, no hatching was observed after 17 days of exposure. After 24 hour of exposure to C. molmol water suspension 70% mortality of newly hatched snails (3-days old) was observed at 50 ppm. In addition, biochemical investigation showed significant differences as compared to the control regarding the total protein content, and the activity of transaminases (AST, ALT) and Lactate dehydrogenase (LD) except a mild decrease in glycogen concentration and alkaline phosphatase activity in digestive gland tissue of snails. Ultrastuctural investigation of exposed snails to C. molmol water suspension showed some alterations in the digestive gland of snails (i.e. marked vaculation, increased lysosomal activity, swollen mitochondria and consumption of stored lipid and glycogen). Based on the toxicity of C. molmol to the aquatic ecosystem at the examined sublethal levels, it is not recommended as a herbal molluscicide.