Biomphalaria Glabrata Say Research Articles

Evaluation of molluscicidal activity of three mangrove species (Avicennia schaueriana, Laguncularia racemosa and Rhizophora mangle) and their effects on the bioactivity of Biomphalaria glabrata Say, 1818.

ABSTRACTSchistosomiasis is a disease of global extent reaching populations in social vulnerability. One of the control measures of this parasitosis is the use of molluscicidal substances that can fight snails of the genus Biomphalaria, intermediate hosts of Schistosoma mansoni. The aim of this work was to study the toxic activity of three mangrove species (Avicennia schaueriana Stapf. & Leech, ex Moldenke, 1939, Laguncularia racemosa (L.) CF Gaertn, 1807 and Rhizophora mangle L. 1753) on the biological activities of snails Biomphalaria glabrata. Hydroalcoholic extracts were prepared from the stem and leaves of each of the three plant species to which mollusks were exposed. The phytochemical analysis of plants showed the presence of important metabolites in the leaves and stems of L. racemosa and R. mangle, such as tannins and saponins, but the absence of these metabolites in A. schaueriana. Leaf and stem extracts of the three plant species showed low molluscicidal activity, not reaching the standards determined by the World Health Organization (WHO, 1983). L. racemosa and R. mangle has interfered with motility, feeding and oviposition of snails, unlike the extracts of A. schaueriana, which had no effect on these activities.

Biological screening of extracts from leaf and stem bark of Croton floribundus Spreng. (Euphorbiaceae).

This work describes the preliminary evaluation of cytotoxic, antimicrobial, molluscicidal, antioxidant and anticholinesterase activities from leaf (LECF) and stem bark alcoholic extracts (BECF) of the species Croton floribundus Spreng. (Euphorbiaceae), popularly known as capixingui or tapixingui. BECF presented significant toxicity (LC50 = 89.6 μg/ml) in the Artemia salina Leach, 1819 (Crustacea: Branchiopoda) bioassay, whereas LECF did not show activity (LC50 > 1000 μg/ml). From DPPH method, the values of IC50 for the LECF and BECF were 61.2 μg/ml and 62.2 μg/ml, respectively, showing that C. floribundus has an expressive antioxidant activity. Antimicrobial susceptibility was evaluated by microdilution technique and only BECF was active against Staphylococcus aureus (MIC = 39.6 μg/ml). The extracts did not present molluscicidal activity against snail Biomphalaria glabrata Say, 1818 (Gastropoda: Planorbidae). Both extracts revealed the presence of several components with an inhibiting capacity of acetylcholinesterase enzyme on the bioautographic assay. C. floribundus showed to be a promising species considering that it exhibited good biological activity in the most assays performed.

Moluscos límnicos como hospedeiros de trematódeos digenéticos de uma região metropolitana da ilha do Maranhão, Brasil

Este estudo se trata do primeiro levantamento malacológico de água doce e de larvas de trematódeos associadas, sem restrição, somente às espécies transmissoras da esquistossomose na região metropolitana da ilha do Maranhão. Dessa forma, objetivou-se caracterizar a diversidade de moluscos límnicos e de sua helmintofauna em ambientes com aspectos ecológicos variados. Os espécimes de gastrópodes foram coletados mensalmente no município de São Luís (MA), entre o período de novembro de 2014 a junho de 2015, em quatro pontos de coleta (P1 – lêntico e impactado, P2- lótico e impactado, P3 – lótico e alterado, P4 – lótico e conservado). Para cada local foram registrados o pH e Oxigênio Dissolvido, além de análise de Coliformes Totais e Escherichia coli. Foi coletado um total de 4112 moluscos límnicos, classificados como se segue: Biomphalaria glabrata Say, 1818 (62,86%), B. straminea Dunker, 1848 (24,71%), Pomacea sp. Perry, 1810 (7,91%), Physa sp. Draparnaud, 1801 (3,41%) e Drepanotrema sp. Crosse & Fischer, 1880 (1,11%). Destes, B. glabrata apresentou-se positivo para cercárias de Schistosoma mansoni e exemplares de Physa sp. e Pomacea sp. estavam infectados com xifidiocercárias. Houve correlação positiva e significativa em relação à pluviometria e a quantidade de moluscos (p<0,05). A maior abundância de espécimes foi registrada em áreas impactadas, bem como maior grau de parasitismo. A ocorrência de xifidiocercária representa o primeiro relato para a região metropolitana da ilha do Maranhão.

Toxicity of some glucose/mannose-binding lectins to Biomphalaria glabrata and Artemia salina

Schistosomiasis or bilharzia, which affects millions of people living in Africa, Asia and Latin America, is closely associated with certain species of aquatic snails. One way of attacking the disease is to eradicate the host snails. Molluscicidal activities of natural compounds are especially important in the widespread control of this tropical disease. As part of our search for natural compounds with molluscicidal properties for the vector control of schistosomiasis, we are now evaluating for the first time the toxicity of the plant lectins from Canavalia brasiliensis (ConBr), Cratylia floribunda (CFL), Dioclea guianensis (Dgui), Dioclea grandiflora (DGL) and Dioclea virgata (Dvir) to Biomphalaria glabrata Say and Artemia salina Leach. Results indicate that all the samples were toxic to A. salina Leach, some of them with values of lethal concentration that kills 90% of the population (LC 90) < 10 μg mL −1. They are also active against B. glabrata Say, killing 100% of adult snails, at a concentration of 50 μg mL −1. The lectins CFL and Dgui possess properties lethal to mollusks, with values of LC 90 = 50.3 μg mL −1 and LC 90 = 41.0 μg mL −1, respectively.

Activities of naphthoquinones against Aedes aegypti (Linnaeus, 1762) (Diptera: Culicidae), vector of dengue and Biomphalaria glabrata (Say, 1818), intermediate host of Schistosoma mansoni

Larvicidal (against Aedes aegypti Linnaeus, 1762) and molluscicidal (against Biomphalaria glabrata Say, 1818) activities of several natural and synthetic naphthoquinones were measured, with significant results. The best larvicidal compound is 3-bromojuglone, while the better molluscicides are 2-bromo- and 3-bromo-5-acetoxy-1,4-naphthoquinones together with the 3-bromo-5-methoxy derivative. The present results reinforce the potential use of substituted hydroxyquinones, their salts and halogenated quinones as very promising compounds against 4th instar larves of Aedes aegypti, the vector of dengue and against adult snail of Biomphalaria glabrata.

Behaviour of albino and melanic variants of Biomphalaria glabrata Say, 1818 (Mollusca: Planorbidae) following infection by Schistosoma mansoni Sambon, 1907

The behaviour of the albino and melanic variants of Biomphalaria glabrata of Belo Horizonte (MG. Brazil) was studied comparatively, in terms of their respective susceptibilities to infection by Schistosoma mansoni of the same origin, through observation of the elimination of cercariae for a three-month period and the calculation of mortality and infection rates, in control and in infected snails. The number of amoebocytes, granulocytes and hyalinocytes in the circulating hemolymph during different periods of infection was analyzed. The evolution of the infection in the tissues was observed by means of histological cross-sections. The melanic variant showed greater susceptibility to infection and a higher mortality rate. The albino variant showed a higher number of circulating amoebocytes, both granulocytes and hyalinocytes. A higher number of degenerated sporocysts were seen in the histological cross-sections of the albino variant. The results suggest that the melanic variant of B. glabrata was more susceptible to infection by S. mansoni than was the albino variant.

Screening of mediterranean Rosaceae plants for their molluscicidal and piscicidal activities

Extracts of increasing polarity of 13 plants belonging to Mediterranean Rosaceae were tested for possible lethal toxicity against Biomphalaria glabrata Say, a snail intermediate host of Schistosoma mansoni Sambon. Due to the search for compounds without toxicity in nontarget organisms, principally fish and humans, the piscicidal toxicity of the active extracts was also evaluated.

Molluscicidal and piscicidal activities of Venezuelan Chrysobalanaceae plants

Extracts of increasing polarity of 6 Venezuelan plants belonging to the Chrysobalanaceae family were tested for possible letal toxicity against Biomphalaria glabrata Say, a snail intermediate hosts of Schistosoma mansoni Sambon. The piscicidal toxicity of the active extracts was also evaluated with the aim of findings compounds without toxicity in nontarget organisms, principally fishes and humans.

EFFECTS OF HEAVY METALS ON SURVIVAL AND GROWTH OF BIOMPHALARIA GLABRATA SAY (GASTROPODA: PULMONATA) AND INTERACTION WITH SCHISTOSOME INFECTION

The effects of dissolved Pb, Cd and Hg on growth and survival of adult Biomphalaria glabrata Say, uninfected and infected with Schistosoma mansoni Sambon, were examined. Pb at concentrations from 0.25-100 M.M, Cd from 0.075-0.25 u.M and Hg from 0.25-1 JJ.M significantly reduced growth and survival of normal snails. With each metal the effects increased with increasing concentration. The LC 25 at 2 wks exposure was 82 ± 19, 0.22 ± 0.04 and 0.94 ± 0.13 M-M (x ± S.E.) for Pb, Cd and Hg, respectively. Snails exposed to heavy metals continued to be reproductively active, but the egg production was highly variable and no significant effect of heavy metal exposure was demonstrated. Infection also decreased survival and growth of snail hosts and infected individuals exposed to heavy metals displayed the greatest mortality. The LC 25 for infected snails at 2 wks exposure was 8 ± 3, 0.9 ± 0.02 and 0.29 ± 0.08 for Pb, Cd and Hg respectively. A significant interaction between heavy metal exposure and infection was apparent. Infected snails were not reproductively active. Cercarial shedding by infected snails was significantly reduced in the presence of heavy metals and by 6 wks shedding had ceased at the highest metal concentrations.

Molluscicidal properties of the new constituents from the stem of Dysoxylum lenticellare on Biomphalaria glabrata

AbstractTwo new alkaloids, 3‐epi‐2, 18‐dimethoxy‐schelhammericine and lenticellarine and a new diterpene, 8β‐methoxysandaracopimarene isolated from the stem of Dysoxylum lenticellare Gillespie were tested against Biomphalaria glabrata Say and found to possess molluscicidal activity.

Electron microscopic localization of chitin using colloidal gold labelled with wheat germ agglutinin.

The lectin wheat germ agglutinin (WGA) has a binding site which is able to bind a sequence of three N-acetyl-glucosamine residues. Therefore, it has a very strong affinity for the polymers of this sugar, especially chitin. Colloidal gold can be labelled with WGA and used as a specific electron-dense marker for the electron-microscopic localization of chitin. The specificity of the WGA-gold binding can be checked by competitive inhibition with 5-10 mM triacetyl chitotriose. The reliability of this method was tested in three species. In the formation zone of the radula of the snail, Biomphalaria glabrata Say, chitin or chitin precursors were localized in vesicles of the odontoblasts, outside the extremely long microvilli of odontoblasts and in the newly formed teeth. The inner peritrophic envelope of the earwig, Forficula auricularia L., is characterized by an orthogonal texture of bundles of microfibrils that are thought to contain chitin. The presence of chitin was proved using the present method. In the peritrophic membranes of the blowfly, Calliphora erythrocephala Meigen, it was possible to differentiate between chitin and glycoproteins which have N-acetylglucosamine residues.

Population density affecting adult shell size of snail Cepaea nemoralis L.

THOMAS et al.1,2 have questioned the ability of molluscs to limit their population size by self inhibition at high densities. They suggest that plant metabolites may have caused the reduction in growth and fecundity of the aquatic snail Biomphalaria glabrata Say ascribed to crowding in previous studies3,4. Field evidence for density-dependent regulation is limited. Yom-Tov5 found that the fecundity of the desert snail Trochoidea seetzeni Pfeiffer was adversely affected by population density; he considered that either self-inhibition or nutritional differences were responsible. While studying the population dynamics and energetics of the land snail Cepaea nemoralis L., we have found evidence for density-dependent effects that cannot readily be explained by resource limitation. In samples of C. nemoralis collected in 1968 to study shell polymorphism (M. A. Palles-Clark, unpublished) a negative correlation was noticed between adult shell diameter and sample size (r =−0.60, P <0.001). Snails were collected from chalk grassland between Beacon Hill and Round Down, West Sussex. A more detailed study carried out in the same area during the summer of 1973 confirmed this effect. The density of adult C. nemoralis was measured by mark-recapture at nine 20 × 20 m sites, situated 100–600 m apart. Each site was sampled in May, June and August. As there were insufficient recaptures to use multiple recapture methods for all sites, adult population densities were estimated for the second sampling occasion using the Lincoln index.

Oxygen Consumption of the Ampullariid Snail Marisa cornuarietis L. in Relation to Body Weight and Temperature

Both in laboratory conditions and during field studies, the South-American freshwater snail Marisa cornuarietis L. depressed populations of the planorbid snail Biomphalaria glabrata Say, an intermediate host of the trematode Schistosoma mansoni Sambon, responsible for bilharziosis in Brazil (OlivierGonzalez et al. 1956, Radke et al. 1961). Demian and Lutfy (1966) showed that during laboratory conditions Marisa reduced populations of Bulinus truncatus Audouin and Lymnea cailliaudi Bourguignat by predation. The latter are freshwater snails from Egypt and transmitters of parasitic worm diseases. Before the capacity of Marisa is utilized to reduce populations of snails spreading Bilharziosis, it is important to know its biology and physiology. Hunt (1961) showed that Marisa tolerates salinities of up to 25 per cent sea water (S = 8.5 %) The anatomy of the alimentary system was studied by Demian (1964), who also investigated the respiratory organs and movements (Demian 1965). Marisa has two respiratory structures, a monopectinate ctenidium and a pulmonary sac. Demian (1965) distinguished three modes of respiration, viz. bronchial respiration, siphonal pulmonary respiration, and direct pulmonary respiration. No quantitative measurements of the oxygen consumption of Marisa cornuarietis have been performed earlier. The purpose of this investigation was to study the respiration in