Showing papers on "Biomphalaria alexandrina published in 2016"

The endocrine disruptor effect of the herbicides atrazine and glyphosate on Biomphalaria alexandrina snails.

Abstract: 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 snailBiomphalaria alexandrina(Mollusca: Gastropoda) as a bioindicator for endocrine disrupters in terms of steroid levels (testosterone (T) and 17β-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.

The Impact of Three Herbicides on Biological and Histological Aspects of Biomphalaria alexandrina, Intermediate Host of Schistosoma mansoni

Abstract: Schistosomiasis remains a public health problem in the developing world. Biomphalaria alexandrina is the intermediate host of Schistosoma mansoni, with a widespread distribution in Egypt. In Egypt molluscicides have been important, but otherwise molluscicides have been of minor significance. They may, however, become important now that WHO talks about eradicating schistosomiasis in some countries and that WHO has finally accepted that snail control is important.The present study investigated the different effects of three commercial herbicidical compounds, Butralin (as Amex 48% EC), glyphosate isopropylammonium (Herphosate 48% SL) and Pendimethalin (Stomp 50% EC) on B. alexandrina. All three compounds were found to have a molluscicidal effect, with Pendimethalin the most toxic over the examined range of concentrations. In addition, at sublethal concentrations, these compounds reduced growth rates and reproductive output (numbers of eggs laid) in exposed B. alexandrina, and it reduced viability of...

Separation of a compound effective against Biomphalaria alexandrina snails from the filtrate of Penicillium janthinellum

Abstract: Biomphalaria alexandrina snails, as intermediate hosts of schistosomiasis, play a central role in dissemination of the disease. Control of these snails by chemical molluscicides adversely affects the aquatic environment, causing toxic and carcinogenic effects on non-target organisms. Searching for promising substances from biological origin becomes an urgent need to overcome these drawbacks. Screening tests were carried out on 236 fungal genera isolated from the habitat of freshwater snails in four Egyptian governorates. Twenty species were effective against B. alexandrina snails, but the most potent was Penicillium janthinellum as the value of LC50 was 1.03%. Chemical analyses of this filtrate resulted in the separation of a compound effective against snails; it was identified as methyl gallate. Protein electrophoresis showed that both fungal filtrate and methyl gallate affect the protein pattern of snails’ haemolymph. Little or no mortality of Daphnia pulex individuals was observed after their exposure ...

Alterations in the fatty acid profile, antioxidant enzymes and protein pattern of Biomphalaria alexandrina snails exposed to the pesticides diazinon and profenfos.

Abstract: The use of pesticides is widespread in agricultural activities. These pesticides may contaminate the irrigation and drainage systems during agriculture activities and pests' control and then negatively affect the biotic and a biotic component of the polluted water courses. The present study aimed to evaluate the effect of the pesticides diazinon and profenfos on some biological activities of Biomphalaria alexandrina snails such as fatty acid profile, some antioxidant enzymes (thioredoxin reductase (TrxR), sorbitol dehydrogenase (SDH), superoxide dismutase (SOD), catalase (CAT) as well as glutathione reductase (GR) and lipid peroxidation (LP)) and protein patterns in snails' tissues exposed for 4 weeks to LC10 of diazinon and profenfos. The results showed that the two pesticides caused considerable reduction in survival rates and egg production of treated snails. Identification of fatty acid composition in snail tissues treated with diazinon and profenfos pesticides was carried out using gas-liquid chromatography (GLC). The results declared alteration in fatty acid profile, fluctuation in percentage of long chain and short chain fatty acid contributions either saturated or unsaturated ones, and a decrease in total lipid content in tissues of snails treated with these pesticides. The data demonstrate that there was a significant inhibition in the activities of tissues SOD, CAT, glutathione reductase (GR), TrxR, and SDH in tissues of treated snails, while a significant elevation was detected in LP as compared to the normal control. On the other hand, the electrophoretic pattern of total protein showed differences in number and molecular weights of protein bands due to the treatment of snails. It was concluded that the residues of diazinon and profenfos pesticides in aquatic environments have toxic effects onB. alexandrina snails.

Molecular approach for detecting early prepatent Schistosoma mansoni infection in Biomphalaria alexandrina snail host.

Abstract: The present study aimed to evaluate a polymerase chain reaction (PCR) assay used for detection of Schistosoma mansoni infection in Biomphalaria alexandrina snails in early prepatent period and to compare between it and the ordinary detection methods (shedding and crushing). Biomphalaria alexandrina snails are best known for their role as intermediate hosts of S. mansoni. DNA was extracted from infected snails in addition to non-infected “negative control” (to optimized the efficiency of PCR reaction) and subjected to PCR using primers specific to a partial sequence of S. mansoni fructose-1,6-bus phosphate aldolase (SMALDO). SMALDO gene was detected in the infected laboratory snails with 70, 85, and 100 % positivity at the 1st, 3rd, and 7th day of infection, respectively. In contrast, the ordinary method was not sensitive enough in detection of early prepatent infection even after 7 days of infection which showed only 25 % positivity. By comparing the sensitivity of the three methods, it was found that the average sensitivity of shedding method compared to PCR was 23.8 % and the average sensitivity of crushing method compared to PCR was 46.4 % while the sensitivity of PCR was 100 %. We conclude that PCR is superior to the conventional methods and can detect positive cases that were negative when examined by shedding or crushing methods. This can help in detection of the areas and times of high transmission which in turn will be very beneficial in planning of the exact timing of the proper control strategy.

Digenetic larvae in Schistosome snails from El Fayoum, Egypt with detection of Schistosoma mansoni in the snail by PCR.

Abstract: The present study aims to detect the digenetic larvae infections in Bulinus truncatus and Biomphalaria alexandrina snails and also PCR detection of Schistosoma mansoni infection. The snails were collected from different branches of Yousef canal and their derivatives in El Fayoum Governorate. The snails were investigated for infection through induction of cercarial shedding by exposure to light and crushing of the snails. The shed cercariae were S. mansoni, Pharyngeate longifurcate type I and Pharyngeate longifurcate type II from B. alexandrina, while that found in B. truncatus were Schitosoma haematobium and Xiphidiocercaria species cercariae. The seasonal prevalence of infection was discussed. Polymerase chain reaction was used for the detection of S. mansoni in the DNA from field collected infected and non infected snails. The results of PCR showed that the pool of B. alexandrina snails which shed S. mansoni cercariae in the laboratory, gave positive reaction in the samples. Pooled samples of field collected B. alexandrina that showed negative microscopic shedding of cercariae gave negative and positive PCR in a consecutive manner. Accordingly, a latent infection in the snail (negative microscopic) could be detected by using PCR.

Gas chromatography-mass spectrometry analysis and antioxidant activity of punica granatum l. peels and its role as immunostimulant against schistosoma mansoni infection in biomphalaria alexandrina

Abstract: Objective: To evaluate the antioxidant activity and chemical composition of Punica granatum L. and test it as immunostimulants against Schistosoma mansoni infection to Biomphalaria alexandrina snails. Methods: Antioxidant activity was evaluated by measuring the free radical scavenging activity of the 90% defatted methanol extract (90% DM) of P. granatum peels and its sub-derived fractions was evaluated via 2,2’-diphenyl-1-picrylhydrazyl and its chemical constituents were identified via gas chromatography-mass spectrometry (GC-MS) analysis. B. alexandrina snails were exposed to pomegranate extracts (PEs) for 1 month before their challenging with S. mansoni miracidia. Infection rates, immunological and histological parameters were, then, evaluated in PE-exposed snails and compared to controls. R esults: The antioxidants activities of PE, expressed as scavenging concentration at 50%, were in the following order; 90% DM (12.45) ˃ n -butanol(15.59) ˃ethyl acetate (21.36) ˃water (49.16) µg/ml, compared to 7.50 µg/ml for ascorbic acid. The infection rates of PE-exposed snails were 20%,50%, 60%, 70%, and 80%, respectively, for 90% DM, n -butanol, ethyl acetate, water, and dichloromethane extracts compared to 95% in control snails. The number of amoebocytes showed a significant increase, clear differentiation, and size increment in exposed snails compared to controls. Moreover, hermaphrodite glands histology shows a full maturity in the formation of reproductive cells in PE-exposed snails. The GC-MS analysis of the 90% DM extract revealed the presence of 36 compounds representing 93.1% of the total composition. Piperidin-4-ol, 1,3-dimethyl-2,4,6-triphenyl (19.87%), and 6,11-dihydroxy-5,12 naphthacenequinone-1-carboxylic acid (7.80%) were the major components. C onclusion: The identified compounds in 90% DM extract of P. granatum may be responsible for the high antioxidant activity of the fruit and it may account for its immunostimulatory effect against S. mansoni infection in B. alexandrina . Ke ywords: Punica granatum L., Antioxidant activity, Biomphalaria alexandrina, Schistosoma mansoni , Infection rate, Gas chromatography-mass spectrometry.

Schistosomicidal and molluscicidal activities of two Junipers species cultivated in Egypt and the chemical composition of their essential oils

Abstract: In the present study, in vitro bioassay screening of total methanolic extracts of two Juniperus species (Juniperus horizontalis Moench. and Juniperus communis L.) cultivated in Egypt for schistosomicidal and molluscicidal activities was carried out. Schistosoma mansoni Sambon worms and Biomphalaria alexandrina (Ehrenberg) snails were used. The screening results showed that both tested extracts had almost similar schistosomicidal activity (LC50 ≈ 91 µg/ml, in 3 days) while J. communis extract possess more potent molluscicidal activity than J. horizontalis (LC50 = 22.9 and 38.9 ppm, after one day, respectively). Analysis of the chemical composition of the essential oils obtained by hydro-distillation of the aerial parts of the two Junipers species was done by GC/MS. Sixty seven (94.32%) components were identified in J. communis oil with homogeraniol (36.95%) being the major constituent, while sixty (95.39%) components were identified in J. horizontalis oil with the main component, bronyl acetate representing 41.17%. Key words: Essential oils, Juniperus, molluscicidal, schistosomicidal.

Experimental evaluation of Odonata nymph in the biocontrol of schistosomiasis intermediate hosts.

Abstract: Objective To evaluate the predatory potential of the Odonata nymph on freshwater snails that serve as intermediate hosts for Schistosoma species ( Bulinus truncatus and Biomphalaria alexandrina ). Methods Observations on the searching, attacking and devouring of the two snail types with series of laboratory-based predation experiments, whose aims were to determine daily predation rate, differential predation, prey preference considering small-, medium- and large-sized snails were conducted. Results Laboratory evaluation revealed that, the Odonata nymph could kill and consume the two intermediate hosts. The number of snails consumed differed according to the snail type, size and density. The times taken for searching and handling times were dependent on the snail size, type and satiation of the predator. The predation rate varied also with respect to snail type, size and density. This study also evaluated that Odonata nymphs consumed more Bulinus truncatus than Biomphalaria alexandrina per unit time, and that there may be a preference for smaller than larger snails. Conclusions According to our observation, the predator, Hemianax ephippiger nymph may be a suitable biocontrol agent in connection with Schistosoma intermediate hosts.

Factors affecting the molluscicidal activity of Asparagus densiflorus and Oreopanax guatemalensis plants and Difenoconazole fungicide on Biomphalaria alexandrina snails

Abstract: Many factors may enhance or suppress the molluscicidal activity regardless of their origin. The present study aims to determine the molluscicidal activity of two plants, namely Asparagus densiflorus and Oreopanax guatemalensis besides, Difenoconazole fungicide against Biomphalaria alexandrina snails, miracidia and cercariae. The most effective agent was Difenoconazole followed by A. densiflorus and O. guatemalensis against B. alexandrina snails, where the LC90 values after 24 h of exposure reached 2.5, 102, and 188 ppm, respectively. Toxicity of tested agents was more pronounced at high temperatures. A. densiflorus and Difenoconazole showed no changes in their activities after their exposure to sunlight for 6 h. Also, neutral and acidic media were favorable for maintaining their toxic action. The presence of aquatic plants, mud particles, and storage period had negative effects on the activities of the tested agents. Both A. densiflorus and Difenoconazole had a fast effect against miracidia and cercariae of Schistosoma mansoni after 3 h of the exposure. Moreover, the tested agents recorded adverse impact on the total reproductive rate of exposed snails. Such effects were supported by histopathological examinations of the hermaphrodite gland. It showed an abnormal necrosis in male and female gametogenic cells, besides a decrease in the number of ova and other gametogenic stages.

Total protein composition of young and adult Biomphalaria alexandrina snails with different compatibilities to Schistosoma mansoni infection.

Abstract: In the current study differentiation of the total proteins among Biomphalaria alexandrina snails at different ages was done to identify the proteins responsible for the snails’ compatibility outcome. The work was conducted on snails that differ in their age and the genetic backgrounds. Four subgroups from the progeny of self reproduced susceptible and resistant snails were studies. Infection rates of these subgroups (young susceptible, adult susceptible, young resistant and adult resistant) were 90%, 75%, 40% and 0% respectively. Using Sodium dodecyl sulphate polyacrylamide gel electrophoresis, differences in protein expression were shown between adult and young snails in different subgroups. Dice similarity coefficient was calculated to determine percentage band sharing among the experimental subgroups. The results revealed that the combination of similarities between both age and compatibility status of the snails has led to the highest similarity coefficient followed by the combination of similarities of both genetic origin and age although they differ in the compatibility status. On the other hand, the differences in the genetic background, age and compatibility status have led to the least similarity index. It was also found that in young snails the genetic background plays the main role in determination of their compatibility, while the internal defense system has the upper hand in determination of adult compatibility. Further characterization of the shared protein bands among the studied subgroups is needed to clarify their role in host-parasite relationship.

Trials of vaccination by lung schistosomula and Biomphalaria alexandrina vaccines against experimental Schistosoma mansoni

Abstract: Background Schistosomulum stage is believed to be the target of protective immunity. Over the past two decades, several investigators have demonstrated the antigenic communion between Schistosoma mansoni and Biomphalaria alexandrina. Objective The present study aimed to evaluate the effect of combining S. mansoni schistosomal lung antigen preparations and B. alexandrina antigen preparations for use as antischistosomal vaccination in murine models, and to compare their efficacy with and without the use of complete Freund’s adjuvant (CFA). Materials and methods Seventy laboratory-bred Swiss albino male mice were used in this study. They were classified into seven groups (10 mice each). Each mouse was sensitized with an initial subcutaneous injection of the extracted antigens. After 2 weeks, a second subcutaneous injection of the same antigen dose was given. Two weeks after the last dose of vaccination, all mice groups were infected with 100 S. mansoni cercariae subcutaneously. Mice were sacrificed by rapid decapitation 7 weeks post-infection for assessment of the inoculated antigens by parasitological (stool egg count, worm burden, tissue egg load, and oogram pattern) and histopathological (hepatic sections stained with hematoxylin and eosin for detection of granuloma number and diameter) studies. Results The data showed that vaccination with combined antigens (S. mansoni schistosomal lung antigen prepations + B. alexandrina antigen preparations with CFA) had the best protective effect. Conclusion The single antigen vaccination did not protect against infection by antigenically complexed S. mansoni. The cocktail vaccine apparently induced an agreeable immune response against many of the antigenic components. This new cocktail represents a promising approach toward the future development of vaccine strategy.

Factors Affecting Lethality of Bisphenol a on Biomphalaria alexandrina Snails

Abstract: The present study was undertaken to investigate the influence of some environmental factors including temperature, water vegetation, bed mud and pH on LC50, LC90 and LT50 of bisphenol A (BPA) on the snail host of Schistosoma mansoni, Biomphalaria alexandrina. Effects of exposure to the sublethal concentrations of BPA on some biological aspects of the snails and on the cercarial output form S. mansoni infected snails were studied. Results showed that temperature, water vegetation, bed mud and pH markedly affected the lethality of BPA.

Characterization of the hemocytes of susceptible and resistant biomphalaria alexandrina snail.

Abstract: The internal defense system consists of soluble components of hemolymph and circulating cells known as hemocytes. The circulating hemocytes play a central role in innate immunity. This work aimed to study the hemocytes of both susceptible and resistant B. alexandrina snails exposed to S. mansoni infection using light and electron microscopes. Two tested groups were included in the study; 60 susceptible and 60 resistant B. alexandrina snails. Both tested groups were studied as regad the hemocyte count (before and after infection) and the morphological characteristics of both circulating and tissue hemocytes by light and electron microscopes. Before infection, .there was no significant difference between the two groups as regard the hemocyte count, however after infection, there is a significant decrease in the circulating hemocytes of the resistant group. Light microscopy revealed five morphological types of circulating cells of both susceptible and resistant snails. Regarding scannig electron microscopy, hemocytes of susceptible snails appeared rounded with smooth or slightly rough surface. However, that of the resistant snails appeared irregular in shaped with corrugated surface. Furthermore, Light microscopy and the transmission electron microscopy revealed signs of cell activation in the hemocytes of the resistant group. The circulating hemocytes consist of five cell types in both susceptible and resistant B. alexandarina and morphologies of these cells are quite similar, but with more signs of cell activations in the resistant group. More specific studies on the functional activities of the hemocytes and mechanisms that may affect or influence the susceptibility and/or non-susceptibility of molluscs to invade microorganisms is essential and how they can act in the immune response.