Embryonic exposure to selenium nanoparticles delays growth and hatching in the freshwater snail Lymnaea stagnalis.

Selenium nanoparticles (SeNPs) have been applied in the biomedical and biocidal domain which may have potential environmental risks for aquatic systems. However, the knowledge of its toxicity and the role of functionalization on aquatic invertebrates are scarce. Thus, the present study aimed to analyze the embryotoxicity of two types of SeNPs coated with Sodium carboxymethyl cellulose (CMC-SeNPs) and Chitosan (CS-SeNPs) to the freshwater snail Lymnaea stagnalis in lake water, focusing on embryonic development. The influence of surface coatings and ions release, on the embryonic development of SeNPs to freshwater snail L. stagnalis was investigated. For this end, the snails were exposed to different concentrations of SeNPs and Se ions (0.05-1 mg L-1) during 7 days and multiple endpoints were analyzed, including developmental stage frequency, morphological alterations, embryos mortality and hatching success. The results showed that both Se forms promoted the developmental delay, mortality, morphological changes, and hatching inhibition in snail embryos in a concentration-dependent manner. CMC-SeNPs are 2.6 times more embryotoxic compared to CS-SeNPs indicating the importance of surface coating on the embryotoxicity. Moreover, the results revealed that although both forms of Se inhibited the embryo development and reduced the hatching of L. stagnalis, the mode of action on the embryogenesis was different. SeNPs had a higher toxicity to snails' embryos compared to their dissolved counterparts. Despite significant dissolution, by comparing the SeNPs with their dissolved fraction, the results suggest SeNPs inhibition effect on the snail development could be caused by both SeNPs and Se4+, and SeNPs might be the major development retardation driver rather than Se ions. The present study evidenced by the first time the toxicity effects of SeNPs on the snail embryogenesis, and highlighted how SeNPs intrinsic properties influence their transformation and toxicity in environmental relevant scenarios.

Long-term exposure to environmental diclofenac concentrations impairs growth and induces molecular changes in Lymnaea stagnalis freshwater snails.

As pharmaceutical substances are highly used in human and veterinary medicine and subsequently released in the environment, they represent emerging contaminants in the aquatic compartment. Diclofenac (DCF) is one of the most commonly detected pharmaceuticals in water and little research has been focused on its long-term effects on freshwater invertebrates. In this study, we assessed the chronic impacts of DCF on the freshwater gastropod Lymnaea stagnalis using life history, behavioral and molecular approaches. These organisms were exposed from the embryo to the adult stage to three environmentally relevant DCF concentrations (0.1, 2 and 10 µg/L). The results indicated that DCF impaired shell growth and feeding behavior at the juvenile stage, yet no impacts on hatching, locomotion and response to light stress were noted. The molecular findings (metabolomics and transcriptomic) suggested that DCF may disturb the immune system, energy metabolism, osmoregulation and redox balance. In addition, prostaglandin synthesis could potentially be inhibited by DCF exposure. The molecular findings revealed signs of reproduction impairment but this trend was not confirmed by the physiological tests. Combined omics tools provided complementary information and enabled us to gain further insight into DCF effects in freshwater organisms.

Molluscicidal effect of Achyranthes aspera L. (Amaranthaceae) aqueous extract on adult snails of Biomphalaria pfeifferi and Lymnaea natalensis.

BACKGROUND: Intestinal schistosomiasis caused by Schistosoma mansoni is a wide spread disease in most parts of Ethiopian highlands. Snail control is one major strategy in schistosomiasis control. The use of molluscicidal plant products is becoming interesting due to their environmental friendliness, accessibility and easy application. This research is aimed to evaluate the molluscicidal effect of Achyranthes aspera on Biomphalaria pfeifferi and Lymnaea natalensis snails, which are of great medical and veterinary importance in Ethiopia. METHODS: Adult B. pfeifferi snails were exposed to the various concentrations of A. aspera aqueous leaf extract for 24, 48 and 72 h. Similarly, adult L. natalensis snails were exposed to the extract for 24 h. Mortality data were analyzed using probit regression model. Phytochemical content of the plant was analyzed using standard screening methods. RESULTS: The plant's molluscicidal effect on the two snail species was demonstrated. The 24 h LC50 and LC90 values against L. natalensis were 69.5 and 93.9 ppm respectively. In the 24, 48 and 72 h exposure of B. pfeifferi, the LC50 values were 72.4, 69.9, 64.7 ppm and the LC90 were 96.5, 93.8, 92.8 ppm, respectively. The phytochemical screening tests indicated presence of saponins. CONCLUSION: From the findings of this study, A. aspera has a molluscicidal potential. The result provides a useful foundation for further in-depth studies to ensure its wider applicability in different water bodies and evaluate its toxic effects on non-target species.

Molluscicidal activity of Solanum elaeagnifolium seeds against Galba truncatula intermediate host of Fasciola hepatica: Identification of ß-solamarine.

CONTEXT: The persistence of fascioliasis in many developing countries urges the search for simple, cheap, and effective substances. In this view, plants provide interesting molluscicidal activities thanks to the secondary metabolites they produce. The genus Solanum is known for its potent effect on vector snails. OBJECTIVE: The molluscicidal activity of Solanum elaeagnifolium Cav. (Solanaceae) seeds against Galba truncatula Müll. (Lymnaeidae), intermediate host of Fasciola hepatica L. (Fasciolidae), was evaluated. MATERIALS AND METHODS: Solanum elaeagnifolium seeds were powdered and successively extracted using n-hexane, methylene chloride, acetone, and methanol, for 20 h each. After filtration, solvents were evaporated. An acid-base treatment was conducted on seed methanolic extract to isolate total alkaloids and ß-solamarine. Total saponins fraction was obtained after successive macerations and evaporations. The molluscicidal activity was evaluated by subjecting snails, in groups of 10, for 48 h to 500 mL of extracts, fractions, and pure product aqueous solutions, each containing amounts, ranging from 1 to 50 mg of plant material in 5 mg increments. RESULTS: The methanolic extract of seeds, ß-solamarine isolated for the first time from this plant and total saponins fraction showed very potent activities on snails, giving respective median lethal concentrations (LC50) of 1.18, 0.49, and 0.94 mg/L. Total alkaloids fraction obtained from the methanolic extract was less active giving an LC50 value of 14.67 mg/L. DISCUSSION AND CONCLUSION: This study emphasizes that glycoalkaloids and saponins of Solanum elaeagnifolium are potent molluscicidal agents. Seed methanolic extract, ß-solamarine, and total saponins fraction may be used as molluscicides.

Comparative toxicity of Paraquat herbicide and some plant extracts in Lymnaea natalensis snails.

Paraquat has been shown to be a highly toxic compound for humans and animals, and many cases of acute poisoning and death have been reported over the past few decades. The present study was undertaken to evaluate comprehensively herbicides (Paraquat) and some plant extracts to biochemical aspects of Lymnaea natalensis snails. It was found that the exposure of L. natalensis to Paraquat and plant extracts led to a significant reduction in the infectivity of Fasciola gigantica miracidia to the snail. The glucose level in hemolymph of exposed snails was elevated, while the glycogen showed a decrease in soft tissues when compared with the control group. In addition, the activity level of some enzymes representing glycolytic enzymes as hexokinase (HK), pyruvate kinase (PK), phosphofructokinase (PFK), lactate dehydrogenase (LDH), and glucose phosphate isomerase (GPI) in snail's tissues were reduced in response to the treatment. It was concluded that the pollution of the aquatic environment by herbicide would adversely affect the metabolism of the L. natalensis snails. Snails treated with Agave attenuate, Ammi visnaga, and Canna iridiflora plant had less toxic effect compared to snails treated with Paraquat.

Efeito moluscicida do óleo essencial de Cymbopogon winterianus Jowitt (Poaceae) sobre Lymnaea columella (Say, 1817) e Biomphalaria tenagophila (D'Orbigny, 1835) / Molluscicidal effect of essential oil of Cymbopogon winterianus Jowitt (Poaceae) on Lymnaea columella (Say, 1817) and Biomphalaria tenagophila (D'Orbigny, 1835)

RESUMO O uso das substâncias moluscicidas convencionais no controle de planorbídeos vetores constitui-se uma importante ferramenta no combate da fasciolose hepática e esquistossomose. Sendo, portanto, de extrema relevância para a pecuária e para os serviços de Vigilância Epidemiológica. Por outro lado, a seleção de caramujos resistentes a tais substâncias e sua baixa seletividade estimulam a busca por novas substâncias. Neste sentido, o presente trabalho foi desenvolvido para avaliar o efeito do óleo essencial de Cymbopogon winterianusJowitt sobre Lymnaea columella e Biomphalaria tenagophila, hospedeiros intermediários de Fasciola hepatica e esquistossomose mansônica, respectivamente. O óleo essencial foi extraído a partir de folhas frescas utilizando o sistema Clevenger. A análise qualitativa foi realizada por meio de cromatografia gasosa acoplada a espectrometria de massas (CG/EM) e a quantificação dos constituintes presentes no óleo foi determinada por cromatografia gasosa acoplada ao detector de ionização de chama (CG/DIC). O efeito moluscicida foi avaliado utilizando seis moluscos de cada espécie e o óleo essencial de C. winterianus nas concentrações finais de 10, 20, 30, 40, 60, 80 e 100 ppm. A análise por cromatografia gasosa do óleo essencial possibilitou a identificação dos componentes majoritários geraniol (28,62%), citronelal (23,62%) e citronelol (17,10%). Os valores de DL100 e DL50para os moluscos das espécies L. columella e B. tenagophila foram, respectivamente, 60 e 40 ppm; 80 ppm e 60 ppm. O óleo de Cymbopogon winterianus demonstrou-se uma alternativa promissora para o controle dos moluscos, sendo a espécie L. columella mais sensível ao mesmo.

ABSTRACT Conventional molluscicides have been employed to control of planorbids vectors and are an important tool in order to control the hepatic fascioliasis and schistosomiasis. Thus, these substances have been showinggreat relevance for both Veterinary and Livestock Services as well as for Epidemiology and Disease Surveillance. On the other hand, the process of drug pressure for the selection of resistant snails to such components and their low selectivity have stimulated the search for new substances. Since researches on new drugs are the starting point to assist on themolluscs control, this work was developed in order to evaluate the effect of Cymbopogon winterianus Jowitt essential oil on L. columella and B. tenagophila, intermediate hosts of Fasciola hepatica and Schistosoma mansoni, respectively. The essential oil was obtained from fresh leaves by hydrodistillation using a Clevenger apparatus. A qualitative analysis was performed by gas chromatography together with a mass spectrometry one (GC/MS) and the chemical constituent content was determined by gas chromatography with a flame ionization detector (GC/FID). The molluscicidal effect was evaluated through the use of six snails of each species and C. winterianus essential oil at 10, 20, 30, 40, 60, 80 and 100 ppm. The result of the gas chromatographic analysis for the essential oil showed geraniol (28.62%), citronellal (23.62%) and citronellol (17.10%) as the major chemical components . The DL100 and DL50 values for L. columella and B. tenagophila species were, respectively, 60 and 40 ppm; 80 ppm and 60 ppm. L. columella had demonstrated more sensitivity to this essential oil than theB. tenagophila species. The C. winterianus essential oil proved to be a promising alternative for the control of these molluscs being the L. columella species the most sensitive of them.

Laboratory evaluation of molluscicidal & mosquito larvicidal activities of leaves of Solanum nigrum L.

BACKGROUND & OBJECTIVES: Indiscriminate use of synthetic pesticides has created serious problem for the aquatic flora and fauna, and also resulted in appearance of pesticide resistance in vector population. This study was designed to evaluate the biocontrol efficacy of aqueous and solvent extracts of mature leaves of Solanum nigrum L., against fresh water snail Lymnaea acuminata f. rufescens (Gray) (an intermediate host of parasites causing fasciolopsiasis) and larvae of Culex vishnui group (Reuben) (vector of Japanese encephalitis). METHODS: Aqueous and solvent extracts of fresh, mature, green/shed dried leaves of S. nigrum were tested against adult L. acuminata and larvae of Cx. vishnui group. The lethal concentration was determined and the appropriate lethal concentration at 24 h of benzene extract was also studied on non target organisms such as Daphnia sp, Diplonychus annulatum and Chironomus circumdatus. A qualitative phytochemical analysis was carried out in search of active ingredient and the chemical nature of the active substance was also evaluated by infrared (IR) analysis. RESULTS: In a 72 h bioassay experiment with the aqueous extract, the highest mortality was recorded in 0.5 and 3 per cent extract against larvae of Cx. vishnui group and L. acuminata, respectivela. In the benzene solvent extract, the maximum mortality was recorded at a concentration of 150 ppm against L. acuminata and at 50 ppm against larvae of Cx. vishnui group with LC 50 values of 55.45 and 11.59 ppm, respectively at 72 h. The log probit analysis (95% confidence level) recorded lowest value at 72 h of exposure. Qualitative phytochemical analysis reported the presence of some biochemical compounds, such as saponin, flavonoids, steroid and tannin. Among these, the toxic compound was detected by IR analysis having Rf=0.87 (showed 66.70% and 76.70% mortality of L. acuminata and larvae of Cx. vishnui group, respectively). IR analysis provided preliminary information about the aliphatic amide nature of the active ingredient. INTERPRETATION & CONCLUSIONS: The study results provide considerable scope in exploiting local indigenous plant resources for molluscicidal and mosquito larvicidal activities.

Effects of single, binary and tertiary combinations with Jatropha gossypifolia and other plant-derived molluscicides on reproduction and survival of the snail Lymnaea acuminata.

The effect of sub-lethal doses (40% and 80% of LC(50)/24h) of plant derived molluscicides of singly, binary (1:1) and tertiary (1:1:1) combinations of the Rutin, Ellagic acid, Betulin and taraxerol with J. gossypifolia latex, leaf and stem bark powder extracts and their active component on the reproduction of freshwater snail Lymnaea acuminata have been studied. It was observed that the J. gossypifolia latex, stem bark, individual leaf and their combinations with other plant derived active molluscicidal components caused a significant reduction in fecundity, hatchability and survival of young snails. It is believed that sub-lethal exposure of these molluscicides on snail reproduction is a complex process involving more than one factor in reducing the reproductive capacity.

EFFECTS OF SINGLE, BINARY AND TERTIARY COMBINATIONS WITH Jatropha gossypifolia AND OTHER PLANT-DERIVED MOLLUSCICIDES ON REPRODUCTION AND SURVIVAL OF THE SNAIL Lymnaea acuminata / Efeitos de combinações unitárias, binárias e terciárias de Jatropha gossypifolia e outros muluscicidas derivados de plantas na reprodução e sobrevivência do caramujo Lymnaea acuminata

The effect of sub-lethal doses (40% and 80% of LC50/24h) of plant derived molluscicides of singly, binary (1:1) and tertiary (1:1:1) combinations of the Rutin, Ellagic acid, Betulin and taraxerol with J. gossypifolia latex, leaf and stem bark powder extracts and their active component on the reproduction of freshwater snail Lymnaea acuminata have been studied. It was observed that the J. gossypifolia latex, stem bark, individual leaf and their combinations with other plant derived active molluscicidal components caused a significant reduction in fecundity, hatchability and survival of young snails. It is believed that sub-lethal exposure of these molluscicides on snail reproduction is a complex process involving more than one factor in reducing the reproductive capacity.

O efeito de doses sub-letais (40% e 80% de LC50/24h) de moluscicidas derivados de plantas com combinações unitárias, binárias (1:1) e terciárias (1:1:1) de Rutin, ácido Elágico, Betulin e taraxerol com látex da J. gossypifolia, folhas e extrato em pó de casca de caule e seus componentes ativos foram estudados na reprodução do caramujo de água fresca Lymnaea acuminata. Foi observado que o látex da J. gossypifolia, casca do caule, folhas individualmente e suas combinações com componentes moluscicidas ativos derivados de outras plantas causaram redução significante na fecundidade, incubação e sobrevivência dos caramujos jovens. Acredita-se que a exposição sub-letal destes moluscicidas sobre a reprodução dos caramujos é processo complexo envolvendo mais de um fator na redução da capacidade reprodutiva.

In vitro phytotherapy of vector snails by binary combinations of larvicidal active components in effective control of fascioliasis.

A food-borne trematode infection fascioliasis is one among common public health problems worldwide. It caused a great economic loss for the human race. Control of snail population below a certain threshold level is one of the important methods in the campaign to reduce the incidence of fascioliasis. The life cycle of the parasite can be interrupted by killing the snail or Fasciola larva redia and cercaria inside of the snail Lymnaea acuminata. In vitro toxicity of different binary combinations (1:1 ratio) of plant-derived larvicidal active components such as citral, ferulic acid, umbelliferone, azadirachtin and allicin against Fasciola redia and cercaria were tested. The mortality of larvae was observed at 2h, 4h, 6h and 8h of treatment. In in vitro condition azadirachtin + allicin (1:1 ratio) was highly toxic against redia and cercaria (8h LC50 0.006 and 0.005 mg/L). Toxicity of citral + ferulic acid was lowest against redia and cercaria larvae.

In vitro PHYTOTHERAPY OF VECTOR SNAILS BY BINARY COMBINATIONS OF LARVICIDAL ACTIVE COMPONENTS IN EFFECTIVE CONTROL OF FASCIOLIASIS / Fitoterapia in vitro de caramujos vetores por combinações binárias de componentes ativos larvicidas como controle efetivo de fasciolíase

SUMMARY A food-borne trematode infection fascioliasis is one among common public health problems worldwide. It caused a great economic loss for the human race. Control of snail population below a certain threshold level is one of the important methods in the campaign to reduce the incidence of fascioliasis. The life cycle of the parasite can be interrupted by killing the snail or Fasciola larva redia and cercaria inside of the snail Lymnaea acuminata. In vitro toxicity of different binary combinations (1:1 ratio) of plant-derived larvicidal active components such as citral, ferulic acid, umbelliferone, azadirachtin and allicin against Fasciola redia and cercaria were tested. The mortality of larvae was observed at 2h, 4h, 6h and 8h of treatment. In in vitro condition azadirachtin + allicin (1:1 ratio) was highly toxic against redia and cercaria (8h LC50 0.006 and 0.005 mg/L). Toxicity of citral + ferulic acid was lowest against redia and cercaria larvae. .

RESUMO A infecção alimentar pelo trematóide da fasciolíase é uma dentre os mais comuns problemas de saúde pública mundiais, causando grande prejuízo econômico para a humanidade. Controle da população de caramujos abaixo de determinado nível é um dos métodos no campo mais importantes para a redução da incidência da fasciolíase. O ciclo de vida do parasita pode ser interrompido pela morte do caramujo ou da larva redia e cercária da Fasciola dentro da Lymnaea acuminata. Foi testada a toxicidade in vitro das diferentes combinações binárias (relação 1:1) entre os vários componentes larvicidas ativos da planta tais como citral, ácido ferúlico, umbeliferone, azadiractina, e alicina contra a Fasciola redia e a cercária. A mortalidade das larvas foi observada após duas, quatro, seis e oito horas de tratamento. A condição in vitro azadiractina + alicina (relação 1:1) foi altamente tóxica contra redia e cercária (8h LC50 0,006 e 0,005 mg/L). Toxicidade do citral + ácido ferúlico foi a mais baixa contra redia e larvas de cercária. .

Laboratory assessment of the molluscicidal and cercariacidal activities of Balanites aegyptiaca.

OBJECTIVE: To assess the molluscicidal and cercariacidal activities of aqueous extracts of Balanites aegyptiaca (B. aegyptiaca) against Ethiopian Biomphalaria pfeifferi (B. pfeifferi), Lymnaea natalensis (L. natalensis) and Schistosoma mansoni (S. mansoni) cercariae. METHODS: Extracts of seeds, endocarp, mesocarp, and fruit of B. aegyptiaca were tested for their activities against adult B. pfeifferi and L. natalensis. The cercariacidal activity of the seeds of the plant was also evaluated against S. mansoni. Bioassays were carried out following the methods recommended by WHO. Snail mortalities were compared between each plant part and snail species, and LC50 and LC90 values for the plant parts tested were computed. The cercariacidal activity of the plant was assessed by exposing the mice to the cercariae pre-exposed to aqueous extract of B. aegyptiaca seeds. RESULTS: For the molluscicidal activities of seeds, endocarp, mesocarp and whole fruit, the LC50 values against B. pfeifferi were 56.32, 77.53, 65.51 and 66.63 mg/L, respectively, while the respective LC90 values were 77.70, 120.04, 89.50 and 97.55 mg/L. Similarly, the LC50 values for the seeds, endocarp, mesocarp and whole fruit against L. natalensis were 80.33, 92.61, 83.52 and 87.84 mg/L, respectively, while the respective LC90 values were 102.30, 138.21, 115.42 and 127.69 mg/L. B. pfeifferi were found to be more susceptible to B. aegyptiaca than L. natalensis. S. mansoni cercariae exposed to 15 mg/L of extract of seeds were incapable of infecting mice. The mean egg load of tissue was reduced in mice infected with the cercariae exposed to 5 and 10 mg/L of the extract. CONCLUSIONS: The aqueous extracts of different parts of B. aegyptiaca exhibited reasonable molluscicidal activity against B. pfeifferi and L. natalensis, as well as cercariacidal activity against S. mansoni cercariae. However, comprehensive laboratory evaluation is recommended prior to field tests of the plant parts since their impact on other aquatic biota is not known.

An efficient analytical platform for on-line microfluidic profiling of neuroactive snake venoms towards nicotinic receptor affinity.

Venomous snakes have evolved their efficient venomous arsenals mainly to immobilize prey. The highly variable toxic peptides in these venoms target a myriad of neurotoxic and haemotoxic receptors and enzymes and comprise highly interesting candidates for drug discovery. Discovery of bioactive compounds from snake venoms, however, is a challenge to achieve. We have developed and applied a methodology to rapidly assess bioactives in a snake venom proteome. Our microfluidic platform opens up efficient and rapid profiling of venomous anti-cholinergic receptor compounds. The key advantages of our methodology are: (i) nano amounts of venom needed; and (ii) a direct correlation of selected bioaffinities with accurate mass. To achieve this, we have for the first time successfully constructed a functional post nano-LC split to MS and bioaffinity profiling. In our method, comprehensive venom profiles with accurate masses and corresponding bioaffinities are obtained in one analytical run and will subsequently allow immediate purification of bioactive peptides with LC-MS, guided by accurate masses of the bioactives only. We profiled several neurotoxic Elapidae snake venoms using our methodology in combination with the acetylcholine binding protein (AChBP) as biological target protein. The latter is a homologue of nicotinic acetylcholine receptors (nAChRs), a drug target in neurodegenerative diseases and cognitive decline such as Parkinson's and Alzheimer's, and in pain related diseases. Our methodology was evaluated and validated with high-affinity α-bungarotoxin and haemotoxic/proteolytic Vipera ammodytes venom spiked with α-bungarotoxin. Thereafter, the methodology was applied to profile the venom proteomes of Dendroaspis jamesoni kaimosae, Naja annulifera and Naja nivea. Gathering comprehensive profiling data took less than 2 h per snake venom measured. The data yielded 20 AChBP ligands of which the corresponding accurate masses were used to retrieve information from literature regarding their function and targeting specificity. We found that from these 20 ligands, 11 were previously reported on, while information on the others could not be found. From these 11 peptides, five have been reported to have nAChR affinity, while the others are reported as cytotoxic, cardiotoxic or as orphan toxin. Our methodology has the potential to aid the field of profiling complex animal venoms for drug discovery.

Laboratory evaluation of the effect of Egyptian native plants against some parasitic vectors.

OBJECTIVE: Four plant extracts possessing molluscicidal and insecticidal efficacy were evaluated under laboratory conditions versus Biomphalaria alexandrina, Lymnea cailliaudi snails, their egg masses and Culex pipiens larvae. These extracts included Grape seed, Eucalyptus, Pomegranate, Verbesina alcoholic extracts, as well as Eucalyptus oil. METHODS: Different mortalities in the exposed vectors were recorded due to the four plant extracts using different concentrations and exposure time. RESULTS: Total snail mortality LC < sub > 100 < /sub > was (100 ppm/12-24h) for Grape seed, (200 ppm/18-24h) for Eucalyptus, (100 ppm/12-18h) for Pomegranate, (100-200 ppm/24h) for Verbesina alcoholic extracts and (100-200 ppm/12h) for Eucalyptus oil. However, only Eucalyptus, Verbesina alcoholic extracts and Eucalyptus oil revealed snail ovicidal effects. LC < sub > 100 < /sub > was (100-200 ppm/24h), (100-200 ppm/24h) & (100-200 ppm/12-48h) respectively. Moreover, the same plant extracts were able to induce total Culex pipiens larvicidal mortality, LC < sub > 100 < /sub > was (200 ppm/48h). However, Grape seed and Pomegranate alcoholic extracts did not induce either snail ovicidal or Culex pipiens larvicidal total mortalities. Activities of the studied plant extracts were considered using reference molluscicidal (Copper sulfate) and insecticidal (Temephos) substances. CONCLUSION: Egyptian native plants continue to provide a wealth of potential sources for biologically active agents that may have a promising role in the production of safe, biodegradable eco-friendly and natural molluscicidal and insecticidal agents.

Characterization of the molluscicidal activity of Bauhinia variegata and Mimusops elengi plant extracts against the fasciola vector lymnaea acuminata / Caracterização da atividade moluscicida dos extratos das plantas Bauhinia variegata e Mimusops elengi contra o vetor da Fasciola, Lymnaea acuminata

The molluscicidal activity of Bauhinia variegata leaf and Mimusops elengi bark was studied against vector snail Lymnaea acuminata. The toxicity of both plants was time and concentration-dependent. Among organic extracts, ethanol extracts of both plants were more toxic. Toxicity of B. variegata leaf ethanolic extract (96h LC50- 14.4 mg/L) was more pronounced than M. elengi bark ethanolic extract (96h LC50-15.0 mg/L). The 24h LC50 of column purified fraction of B. variegata and M. elengi bark were 20.3 mg/L and 18.3 mg/L, respectively. Saponin and quercetin were characterized and identified as active molluscicidal component. Co-migration of saponin (Rf 0.48) and quercetin (Rf 0.52) with column purified bark of M. elengi and leaf of B. variegata on thin layer chromatography demonstrate same Rf value i.e. 0.48 and 0.52, respectively. The present study clearly indicates the possibility of using M. elengi and/or B. variegata as potent molluscicide.

A atividade moluscicida das folhas da Bauhinia variegata e da casca do Mimusops elengi foi testada contra o vetor caracol, Limnaea acuminata. A toxicidade de ambas as plantas é dependente do tempo e da concentração. Entre os extratos orgânicos, os extratos de etanol de ambas as plantas foi mais tóxico. A toxicidade do extrato etanólico da folha da B. variegata (96 h LC50 - 14,4 mg/L) foi mais pronunciada do que o extrato etanólico da casca do M. elengi (96h - LC50 - 15,0 mg/L). As frações purificadas em coluna durante 24 h LC50 do B. variegata e da casca do M. elengi foram 20,3 mg/L e 18,3 mg/L, respectivamente. A saponina e a quercentina foram caracterizadas e identificadas como os componentes ativos moluscicidas. A co-migração da saponina (Rf 0,48) e da quercentina (Rf 0,52) com a casca purificada por coluna do M. elengi e as folhas da B. variegata na cromatografia demonstraram o mesmo valor Rf isto é, 0,48 e 0,52 respectivamente. O presente estudo indica claramente a possibilidade de usar M. elengi e/ou B. variegata como moluscicidas potentes.

Characterization of the molluscicidal activity of Bauhinia variegata and Mimusops elengi plant extracts against the fasciola vector Lymnaea acuminata.

The molluscicidal activity of Bauhinia variegata leaf and Mimusops elengi bark was studied against vector snail Lymnaea acuminata. The toxicity of both plants was time and concentration-dependent. Among organic extracts, ethanol extracts of both plants were more toxic. Toxicity of B. variegata leaf ethanolic extract (96h LC50- 14.4 mg/L) was more pronounced than M. elengi bark ethanolic extract (96h LC50-15.0 mg/L). The 24h LC50 of column purified fraction of B. variegata and M. elengi bark were 20.3 mg/L and 18.3 mg/L, respectively. Saponin and quercetin were characterized and identified as active molluscicidal component. Co-migration of saponin (Rf 0.48) and quercetin (Rf 0.52) with column purified bark of M. elengi and leaf of B. variegata on thin layer chromatography demonstrate same Rf value i.e. 0.48 and 0.52, respectively. The present study clearly indicates the possibility of using M. elengi and/or B. variegata as potent molluscicide.

Molecular cloning and characterization of leucine aminopeptidase from Fasciola gigantica.

M17 leucine aminopeptidase (LAP) is one of a family of metalloexopeptidases, of which short peptide fragments are cleaved from the N-terminals. In this study, the full length of cDNA encoding Fasciola gigantica LAP (FgLAP) was cloned from adult parasites. The amino acid sequences of FgLAP showed a high degree of identity (98%) with that from Fasciola hepatica and a low degree of identities (11% and 9%) with those from cattle and human. Phylogenetic analysis revealed that the FgLAP was closely related and grouped with F. hepatica LAP (FhLAP). Northern analysis showed that FgLAP transcriptional products have 1800 base pairs. Analysis by RNA in situ hybridization indicated that LAP gene was expressed in the cecal epithelial cells of adult parasites. A polyclonal antibody to a recombinant FgLAP (rFgLAP) detected the native LAP protein in various developmental stages of the parasite. In a functional test, this rFgLAP displayed aminolytic activity using a fluorogenic Leu-MCA substrate, and was significantly inhibited by bestatin. Its maximum activity was at pH 8.0 and enhanced by Mn(2+) ions. Localization of LAP proteins by immunohistochemistry and immunofluorescence techniques indicated that the enzyme was distributed in the apical cytoplasm of cecal epithelial cells. Because of its important metabolic role and fairly exposed position, FgLAP is a potential drug target and a possible vaccine candidate against fasciolosis.

Tertiary combination of freeze-dried urine of Indian breeds of cow with plant products against snail Lymnaea acuminata.

Snail Lymnaea acuminata is the intermediate host of liver fluke Fasciola gigantica, which cause endemic fasciolosis among cattle population of eastern Uttar Pradesh. Control of snail population by molluscicides is one of the effective methods to control fasciolosis. In the present study molluscicidal activity of tertiary combination of freeze-dried urine of different Indian breeds of cow Sahiwal, Geer and Tharparkar with Annona squamosa seed powder, Ferula asafoetida root latex, Azadirachta indica oil and Camellia sinensis leaves have been tested against Lymnaea acuminata. It was noted that the toxicity of tertiary combination (1:1:5) of cow urine kept for 15 days in sunlight or laboratory condition with different plant products were highly toxic against snail L. acuminata. 96 h LC50 of tertiary combinations with Sahiwal urine kept for 15 days in sunlight with A. squamosa, F. asafoetida, A. indica oil and C. sinensis were 35.47 mg L(-1), 37.13 mg L(-1), 33.66 mg L(-1), respectively higher than the Geer and Tharparkar. The toxicity of Sahiwal urine kept for 15 days in laboratory condition with A. squamosa and C. sinensis (96 h LC50 28.28 mg L(-1)) was more potent than the all other combinations. Cow urine in combination with plant product can be used for effective control of snail.

Virtual screening against acetylcholine binding protein.

The nicotinic acetylcholine receptors (nAChRs) are a member of the ligand-gated ion channel family and play a key role in the transfer of information across neurological networks. The X-ray crystal structure of agonist-bound α(7) acetylcholine binding protein (AChBP) has been recognized as the most appropriate template to model the ligand-binding domain of nAChR for studying the molecular mechanism of the receptor-ligand interactions. Virtual screening of the National Cancer Institute diversity set, a library of 1990 compounds with nonredundant pharmacophore profiles, using AutoDock against AChBPs revealed 51 potential candidates. In vitro radioligand competition assays using [(3)H] epibatidine against the AChBPs from the freshwater snails, Lymnaea stagnalis, and from the marine species, Aplysia californica and the mutant (AcY55W), revealed seven compounds from the list of candidates that had micromolar to nanomolar affinities for the AChBPs. Further investigation on α(7)nAChR expressing in Xenopus oocytes and on the recombinant receptors with fluorescence resonance energy transfer (FRET)-based calcium sensor expressing in HEK cells showed that seven compounds were antagonists of α(7)nAChR, only one compound (NSC34352) demonstrated partial agonistic effect at low dose (10 µM), and two compounds (NSC36369 and NSC34352) were selective antagonists on α(7)nAchR with moderate potency. These hits serve as novel templates/scaffolds for development of more potent and specific in the AChR systems.

Bait formulations of molluscicides and their effects on biochemical changes in the ovotestis of snail Lymnaea acuminata (Mollusca; Gastropoda:Lymnaeidae).

The effect of sub-lethal feeding of bait formulations containing molluscicidal component of Ferula asafoetida (ferulic acid, umbelliferone), Syzygium aromaticum (eugenol) and Carum carvi (limonene) on biochemical changes in the ovotestis of snail Lymnaea acuminata were studied. Bait formulations feeding to L. acuminata were studied in clear glass aquaria having diameter of 30 cm. Baits were prepared from different binary combinations of attractant amino acid (valine, aspartic acid, lysine and alanine 10 mM) in 100 mL of 2% agar solution + sub-lethal (20% and 60% of 24h LC50) doses of different molluscicides (ferulic acid, umbelliferone, eugenol and limonene). These baits caused maximum significant reduction in free amino acid, protein, DNA, RNA levels i.e. 41.37, 23.56, 48.36 and 14.29% of control in the ovotestis of the snail, respectively. Discontinuation of feeding after treatment of 60% of 96h LC50 of molluscicide containing bait for next 72h caused a significant recovery in free amino acid, protein, DNA and RNA levels in the ovotestis of L. acuminata.