Publications

TitleAbstractYear
Filter
PMID(sorted ascending)
Filter
[compatibility between nine strains of biomphalaria glabrata coming from endemic and non-endemic areas and one strain of schistosoma mansoni from venezuela].nine lots of 32 b. glabrata snails (5-7mm in diameter) from the following strains from the endemic area: cagua, valencia lake (puerta negra sector), ingenio bolívar (aragua state), mariara, caserío el 25 and güigüe (carabobo state), and from the non-endemic area: anzoátegui (lara state), chabasquén (portuguesa state) and caripe (monagas state) were experimentally infected (5 miracidiums/snail) with c5 schistosoma mansoni strain. the intramolluscal prepatent period oscillated between 23 and 25 da ...199910881105
microsatellite variation in the freshwater schistosome-transmitting snail biomphalaria glabrata. 200010886671
[a malacological survey in city parks in belo horizonte, minas gerais, brasil]the greater metropolitan area of belo horizonte currently contains 18 city parks (also known as "ecological parks") with various bodies of water (lakes, springs, streams, etc). initial research in 17 of these parks showed the occurrence of intermediate mollusk hosts for schistosoma mansoni in at least 4. monthly captures done from august 1994 to february 1996 showed the following results for these planorbids: julien rien park: 1,145 specimens of biomphalaria glabrata (2 to 13 mm); betânia park: ...199710886861
toxicity of euphorbia milii latex and niclosamide to snails and nontarget aquatic species.the toxicity of euphorbia milii molluscicidal latex and niclosamide (ncl) to target snails (biomphalaria glabrata and biomphalaria tenagophila) and nontarget aquatic organisms is evaluated. planorbidae snails were killed by very low concentrations of lyophilized latex (48-h lc(50), mg/l: b. glabrata, 0.12; b. tenagophila, 0.09; helisoma duryi, 0.10). latex was less toxic (48-h lc(50) or ec(50), mg/l) to oligochaeta (tubifex tubifex, 0.31), planktonic crustacea (daphnia similis, 0.38; c. dubia, 1 ...200010903832
toxic activities of the plant jatropha curcas against intermediate snail hosts and larvae of schistosomes.the aim of studies on plant molluscicides is to complement methods for controlling snails acting as intermediate hosts of schistosomes. we report on the toxic activity of extracts from jatropha curcas l. (euphorbiaceae) against snails transmitting schistosoma mansoni and s. haematobium. we studied different extracts' effects on infectious larvae, cercariae and miracidia of s. mansoni. compared to aqueous extract, methanol extract showed the highest toxicity against all tested organisms with lc10 ...200010929142
[susceptibility of biomphalaria glabrata to schistosoma mansoni from venezuela and brazil].schistosoma mansoni partially develops its life cycle into snails of the family planorbid. biomphalaria glabrata represents an important host-intermediate. this paper reports experimental infection with miracidia vs. snail in sympatric and parapatric combination. the infection assay to sympatric combination were: bh snail (belo horizonte, brasil) vs. a common geographic origin parasite, and barbula, carabobo state, venezuela vs. sm venezuela parasitic. the parapatric combination were: bh snail v ...199910932760
[ecoepidemiology of urban schistosomiasis in itamaracá island, pernambuco, brazil].in 1988, 22 autochthonous cases from accidental exposure were registered in forte orange beach, itamaracá island, pernambuco, brazil. all cases occurred in middle-to-upper class individuals who were vacationing in the island. after the cases were identified, the major objective was to find breeding sites of schistosomiasis vectors and correlate the biological factors with the environmental conditions.200010973151
schistosome invasion of human skin and degradation of dermal elastin are mediated by a single serine protease.aquatic larvae (cercariae) of the trematode parasite schistosoma mansoni rapidly penetrate human skin by degrading host proteins including elastin. two serine proteases, one chymotrypsin-like and the second trypsin-like, have been proposed to be involved. to evaluate the relative roles of these two proteases in larval invasion, both were purified, identified by sequence, and then biochemically characterized. the trypsin-like activity was resolved into two distinct serine proteases 76% similar in ...200010993899
biological control of the snail hosts of schistosomiasis in areas of low transmission: the example of the caribbean area.the biological control of schistosomiasis has already proven its efficiency in several habitats in the caribbean area. two main types of biological control agents, either trematode parasites or competitor snails have been studied and tested against the snail hosts of schistosomiasis in this region. the first one, ribeiroia guadeloupensis, a trematode sterilizing biomphalaria glabrata was successfully tested in a guadeloupean pond housing a natural population of b. glabrata. the second agent invo ...200010996120
influence of microgravity on crystal formation in biomineralization.biomineralized tissues are widespread in animals. they are essential elements in skeletons and in statocysts. the function of both can only be understood with respect to gravitational force, which has always been present. therefore, it is not astonishing to identify microgravity as a factor influencing biomineralization, normally resulting in the reduction of biomineralized materials. all known biominerals are composite materials, in which the organic matrix and the inorganic materials, organize ...200011007601
molluscicidal activity of 2-hydroxy-3-alkyl-1,4-naphthoquinones and derivatives.in the search for new molluscicidal agents we tested the activity of lapachol and other 2-hydroxy-3-alkylnaphthoquinones possessing nitrogenated alkyl chains, against the snail biomphalaria glabrata. lapachol, isolapachol and nor-lapachol showed strong molluscicidal activity against the adult snail (ld(90)<10 ppm) and significant toxicity against snail egg masses (ld(90)<0.2 ppm). as lapachol is easily extracted, and the derivatives can be synthesised without any difficulty, large-scale synthesi ...200011027788
comparative studies for development of schistosoma mansoni sporocysts in puerto rican and brazilian biomphalaria glabrata.the development of sporocysts of schistosoma mansoni was monitored in pigmented and albino biomphalaria glabrata from puerto rico and brazil. the snails were exposed individually to 20 miracidia, and sporocysts were allowed to develop for 3 to 12 weeks. most of the immature sporocysts were found in the seminal receptacle sac and vas deferens during development. in contrast, mature daughter sporocysts were detected everywhere except in the foot at 12 weeks after exposure to the miracidia. it was ...200011043519
[assessment of schistosomiasis and other intestinal parasitoses in school children of the bambuí municipality, minas gerais, brazil].this work was carried out with the purpose of determining the prevalence of intestinal parasitoses in the school children of bambuí, through parasitological examinations (direct and kato-katz methods) and reevaluating the snails' breeding places described in the county. of the 2,091 school children examined, 20.1% had at least one parasitic infection. giardia lamblia, entamoeba coli, ascaris lumbricoides and hookworm are the most frequent parasites, with a prevalence of 6.2%, 6.2%, 4.8% and 1.4% ...200011064579
calcium carbonate modifications in the mineralized shell of the freshwater snail biomphalaria glabrata.the mineralized shell (consisting of calcium carbonate) of the tropical freshwater snail biomphalaria glabrata was investigated with high resolution synchrotron x-ray powder diffractometry and x-ray absorption spectroscopy (exafs). parts from different locations of the snail shell were taken from animals of different age grown under various keeping conditions. additionally, eggs with ages of 60, 72, 120, and 140 hours were examined. traces of aragonite were found as first crystalline phase in 12 ...200011073237
calcium binding constituents of the organic shell matrix from the freshwater snail biomphalaria glabrata.the ca2+ binding of an edta-free water-soluble (sm) and -insoluble (im) organic matrix of the freshwater snail biomphalaria glabrata was investigated, using a 45ca2+ autoradiography after sds-electrophoretical separation and a calcium binding assay. electrophoresis of the sm showed a considerable amount of alcian blue and stains all positive material, regarded as glycosaminoglycans (gags) or proteoglycans (pgs). this part of the sm was slightly positive after 45ca2+ autoradiography at ph 6.8. th ...200011079377
mechanisms underlying digenean-snail specificity: role of miracidial attachment and host plasma factors.digenetic trematodes usually show a high degree of specificity for their molluscan intermediate hosts. a panel of 4 digenean species (echinostoma paraensei, e. trivolvis, schistosoma mansoni, and schistosomatium douthitti) and 5 snail species (biomphalaria glabrata, helisoma trivolvis, lymnaea stagnalis, stagnicola elodes, and helix aspersa representing 3 gastropod families) was used to assess the relative contributions of miracidial behavior, host plasma osmolality, and host plasma factors in d ...200011128473
a comparative study of mechanisms underlying digenean-snail specificity: in vitro interactions between hemocytes and digenean larvae.a panel of 4 digenetic trematode species (echinostoma paraensei, e. trivolvis, schistosoma mansoni, and schistosomatium douthitti) and 5 snail species (biomphalaria glabrata, helisoma trivolvis, lymnaea stagnalis, stagnicola elodes, and helix aspersa) was examined to determine if known patterns of host specificity could be explained by the tendency of digenean larvae to be bound by snail hemocytes, or by the ability of larvae to influence the spreading behavior of hemocytes. in short-term (1 hr) ...200011128474
molecular evidence supports an african affinity of the neotropical freshwater gastropod, biomphalaria glabrata, say 1818, an intermediate host for schistosoma mansoni.freshwater snails of the genus biomphalaria, preston 1910, are the most important and widely distributed intermediate hosts of schistosoma mansoni, the blood fluke responsible for human intestinal schistosomiasis, in africa and the neotropics. s. mansoni is thought to have been imported repeatedly into the americas during the last 500 years with the african slave trade. surprisingly considering that the new and old world separated 95-106 million years (myr) ago, the disease rapidly became establ ...200011133023
neutral lipids in cercariae, encysted metacercariae, and rediae of echinostoma caproni.high performance thin-layer chromatography (hptlc) was used to analyse the neutral lipids in the rediae, cercariae, and encysted metacercariae of echinostoma caproni from biomphalaria glabrata snails. visual observations of the chromatograms showed that the most abundant lipid fraction in all stages was free sterol. quantification of the free sterol revealed mean weights of 2.7 +/- 0.64 ng per redia, 0.53 +/- 0.023 ng per cercaria, and 0.081 +/- 0.0098 ng per encysted metacercaria. oil red o sta ...200011138028
biodegradability of the molluscicidal saponins of phytolacca dodecandra.the biodegradability of water-extracted saponins of berries from the endod plant, phytolacca dodecandra l'herit, was evaluated under oecd standardized conditions. persistence of the saponins was evaluated by determination of saponin concentrations in water over a 30-day period, using a quantitative hplc method and a semiquantitative hemolytic assay, which is considered a potential field method. the two methods were compared. bioassays were simultaneously conducted using biomphalaria glabrata fre ...200011162718
effects of the serotonin receptor ligand methiothepin on reproductive behavior of the freshwater snail biomphalaria glabrata: reduction of egg laying and induction of penile erection.the biogenic monoamine serotonin (5-ht) has been reported to enhance egg laying in the freshwater gastropod biomphalaria glabrata, an intermediate host for human blood flukes. methiothepin, a vertebrate 5-ht(1/2) receptor ligand which binds with high affinity to a 5-ht receptor (5-htlym) in lymnaea stagnalis was tested for its ability to block egg laying in b. glabrata as a possible target for snail control. a single 30-min application of methiothepin (1 microm) was sufficient to prevent egg lay ...200111170017
galactan biosynthesis in snails: a comparative study of beta-(1--> 6) galactosyltransferases from helix pomatia and biomphalaria glabrata.adult snails synthesize in their albumen glands a polysaccharide which is composed exclusively of d- or d- and l-galactose (gal) residues which are interglycosidically linked by 1 --> 3 and 1 --> 6 bonds. it is the only carbohydrate source for embryos and freshly hatched snails. two galactosyltransferases are described in this study which are most likely involved in the biosynthesis of this polysaccharide. one identified in helix pomatia acts on oligosaccharides and could be used to synthesize a ...200011192266
effects of diet on the development of schistosoma mansoni in biomphalaria glabrata and on the neutral lipid content of the digestive gland-gonad complex of the snail.in a previous study, when the snail biomphalaria glabrata was infected with schistosoma mansoni and maintained on a diet of hen's egg yolk, it produced fully developed cercariae in about one-half the time taken by snails fed romaine lettuce. increased lipids were also noted in the snails fed the yolk diet. the purpose of the present study was to further investigate nutritional effects of a high-lipid diet on larval schistosome development and to reexamine the time to cercarial patency in infecte ...200111227897
the origins, fate, and ecological significance of free amino compounds released by freshwater pulmonate snails.the mass-specific accumulation rates (msar) of both total (tfac) and individual free amino compounds (fac) in conditioned media were measured by hplc, using the orthophthaldialdehyde (opa) methods, in the following cases: (a) laboratory-reared freshwater snails (b. glabrata) with chemosterilized shells; (b) biomphalaria glabrata with non-chemosterilized shells; (c) b. glabrata faeces; (d) isolated shells of b. glabrata; and (e) 10 other species of freshwater gastropods from the lewes brooks, eas ...199811253805
molluscicidal and trypanocidal activities of lapachol derivatives.the activity of the potassium salt of lapachol against the snail biomphalaria glabrata and its egg masses was tested. the obtained ic50 values (2.70 ppm and 1.43 ppm, respectively) are indicative of a strong activity. lapachol derivatives were also assayed against infective trypomastigote blood forms of t. cruzi and the triacetoxy derivative of reduced lapachol showed relevant trypanocidal activity, killing 95.7% of the parasites at the concentration of 42 microg/ml.200111270734
isoterchebulin and 4,6-o-isoterchebuloyl-d-glucose, novel hydrolyzable tannins from terminalia macroptera.two new hydrolyzable tannins, isoterchebulin (1) and 4,6-o-isoterchebuloyl-d-glucose (2), together with six known tannins, 3-8, were isolated from the bark of terminalia macroptera. their structures were elucidated by extensive 1d and 2d nmr studies, ms, and chemical transformations. biological activities of all compounds were evaluated against the snail biomphalaria glabrata, the bacteria bacillus subtilis and pseudomonas fluorescens, the nematode caenorhabditis elegans, and four cancer cell li ...200111277742
interspecific competition between freshwater snails of medical importance: a venezuelan example.lake valencia is located in the centre of the endemic area of the intestinal schistosimiasis in venezuela. the dominance of two pulmonate species, biomphalaria glabrata and b. prona., was observed in the lake. both species are strongly associated with two distinct types of habitats suggesting that competition is occurring between these two species. b. glabrata and b. prona play the role of intermediate hosts of schistosomes in venezuela. at the present time, parasite transmission is not occurrin ...200111280046
the molluscicidal activity of the latex of euphorbia splendens var. hislopii on melanoides tuberculata (thiaridae), a snail associated with habitats of biomphalaria glabrata (planorbidae).the use of the latex of euphorbia splendens var. hislopii was considered as an effective control method for biomphalaria glabrata in sumidouro, rio de janeiro. however, the appearance and expansion of the snail melanoides tuberculata since august 1997, with the concomitant reduction of the population of b. glabrata suggest that competitive exclusion might be taking place. depending on the susceptibility of the thiarid to the e. splendens toxin, the natural control that is occurring could be inte ...200111285483
male-female larval interactions in schistosoma mansoni-infected biomphalaria glabrata.this paper investigates schistosoma mansoni male-female larval interactions in simultaneous bi-miracidial biomphalaria glabrata infections. larval interactions were analysed at four levels of infection: (i), miracidial infectivity, estimated by the prevalence of mollusc infection; (ii), mollusc pathology, measured by the mollusc growth and survival; (iii), dynamics of the cercarial sex ratio; and (iv), cercarial infectivity, measured as the success of development into adulthood. our results show ...200111306113
synthesis, electrochemistry, and molluscicidal activity of nitroaromatic compounds: effects of substituents and the role of redox potential.abstract-molluscicidal bioassays and electrochemical studies (measurement of first wave reduction potential, epcl) were performed on several synthetic nitroaromatics, in relation to possible correlation between biological activity, redox potential and structural effects. five of them presented a significant molluscicidal activity on biomphalaria glabrata (ld50 < 20 ppm). the epc1 values ranged from -0.532 to -0.857 v versus ag/agcl (0.1 m) (-0.260 to -0.585 v versus nhe), all of them, in the fav ...200111310601
molluscicidal properties of some species of annona.in search for plant molluscicides for the vector control of schistosomiasis, ethanolic extracts from different parts of six species of the annonaceae family were evaluated against adult forms and egg masses of biomphalaria glabrata. results from accurate experiments indicate that the majority of analyzed extracts possess properties lethal to biomphalaria glabrata, some of them with significant ld90 values (< 20 ppm), as showed for annona crassiflora m: [pulp and seed (ld50 = 13.21), steem (2.34) ...200111315753
killing of schistosoma mansoni sporocysts by hemocytes from resistant biomphalaria glabrata: role of reactive oxygen species.the fate of schistosoma mansoni (trematoda) sporocysts in its molluscan host biomphalaria glabrata (gastropoda) is determined by circulating phagocytes (hemocytes). when the parasite invades a resistant snail, it is attacked and destroyed by hemocytes, whereas in a susceptible host it remains unaffected. we used 3 inbred strains of b. glabrata: 13-16-r1 and 10-r2, which are resistant to the pr-1 strain of s. mansoni, and m-line oregon (mo), which is susceptible to pr-1. in an in vitro killing as ...200111318558
effect of miracidial dose on adoptively transferred resistance to schistosoma mansoni in the snail intermediate host, biomphalaria glabrata.adoptively transferred resistance to schistosoma mansoni in the snail intermediate host biomphalaria glabrata was measured as a function of miracidial challenge dose. schistosome-susceptible snails implanted with the amebocyte-producing organ (apo) from resistant donors showed 29 and 39% prevalences of infection after challenge with 5 and 10 miracidia, respectively, but 68-83% prevalences when exposed to 25-200 miracidia. prevalences in control (untampered) susceptible snails ranged from 97 to 1 ...200111318589
differential gene expression in haemocytes of the snail biomphalaria glabrata: effects of schistosoma mansoni infection.parasite encapsulation and destruction in biomphalaria glabrata has been shown to involve the cellular component of the snail's internal defence system, the haemocytes. to identify genes involved in the immunobiology of these cells, we used the method of differential display reverse transcriptase polymerase chain reaction (ddrt-pcr) to investigate differential gene regulation in haemocytes isolated from schistosoma mansoni exposed and unexposed snails. rna isolated from circulating haemocytes fr ...200111336750
[host parasite relationship among 3 schistosoma mansoni and 6 biomphalaria glabrata strains from epidemic and no epidemic venezuelan areas is studied].six lots of 18 b. glabrata from: la victoria, turmero, cagua in aragua state; caserío el 25 in carabobo state, chabasquén in portuguesa state and humocaro bajo in lara state, were experimentally infected with miracidia of sm, c5 and c6 strains of schistosoma mansoni (18 snails/schistosoma mansoni strain). the averages of the intramolluscal period (imp) obtained for the s. mansoni strains were very similar and comprised between 35.4 and 36.1 days. no significative statistical differences in the i ...200011338975
isolation and characterization of an alpha-macroglobulin from the gastropod mollusc helix pomatia with tetrameric structure and preserved activity after methylamine treatment.a proteinase inhibitor with m(r) 697000 and 20.3% (w/w) carbohydrate was isolated from the haemolymph of the snail helix pomatia and characterized. it was shown to have a tetrameric structure with subunits disulphide linked by two. it inhibited the activity of several types of proteinases against large substrates but not that of trypsin against n-alpha-benzoyl-dl-arginine-4-nitroanilide. this indicated a nonspecific and steric hindrance mode of inhibition. the ratio of trypsin molecules inactiva ...200111342036
characterization of an insulin receptor-related receptor in biomphalaria glabrata embryonic cells.tyrosine kinase receptors play a key role in the communication of cells with their environment. growth hormone receptors, such as insulin receptors, are involved in the regulation of cell growth, differentiation and metabolism in multicellular organisms. insulin-related peptides and members of the insulin receptor subfamily have been described in a wide variety of invertebrates, including freshwater molluscs. in this paper, we describe the metabolic effect of insulin on a mollusc cell line (bge) ...200111342169
the control of the schistosome-transmitting snail biomphalaria glabrata by the plant molluscicide euphorbia splendens var. hislopii (syn milli des. moul): a longitudinal field study in an endemic area in brazil.under laboratory conditions, latex from euphorbia splendens has shown promise as a plant molluscicide for control of biomphalaria species, intermediate hosts for schistosoma mansoni. the purpose of this study was to evaluate its efficiency under field conditions. application of filtered latex at 12 ppm to one stream in an endemic rural area in minas gerais state, brazil, in september 1995, did result in a reduction in snail density as compared to an untreated stream but the snail population reco ...200111369309
structure of two frep genes that combine igsf and fibrinogen domains, with comments on diversity of the frep gene family in the snail biomphalaria glabrata.upon exposure to infection with digenetic trematodes such as echinostoma paraensei, the freshwater snail biomphalaria glabrata produces increased quantities of hemolymph lectins, some of which are unique polypeptides containing both immunoglobulin superfamily (igsf) and fibrinogen domains. these unusual lectins have been termed fibrinogen-related proteins (freps), and recognize and precipitate digenean antigens. we here report 11 distinct frep-encoding sequences from b. glabrata, and provide the ...200111376947
genetic variability in brazilian populations of biomphalaria straminea complex detected by simple sequence repeat anchored polymerase chain reaction amplification.biomphalaria glabrata, b. tenagophila and b. straminea are intermediate hosts of schistosoma mansoni, in brazil. the latter is of epidemiological importance in the northwest of brazil and, due to morphological similarities, has been grouped with b. intermedia and b. kuhniana in a complex named b. straminea. in the current work, we have standardized the simple sequence repeat anchored polymerase chain reaction (ssr-pcr) technique, using the primers (ca)8ry and k7, to study the genetic variability ...200111391428
parasite (schistosoma mansoni) and host (biomphalaria glabrata) genetic diversity: population structure in a fragmented landscape.random amplified polymorphic dna (rapd) markers were used to quantify genetic diversity within and between 5 populations of schistosoma mansoni within its definitive host (rattus rattus) and the 5 corresponding populations of the snail intermediate host (biomphalaria glabrata) from a limited endemic area of murine schistosomiasis on the island of guadeloupe. analysis of molecular variance (amova) and canonical correspondence analysis (cca) were used to test the significance of genetic differenti ...200111393828
differential display analysis of hemocytes from schistosome-resistant and schistosome-susceptible intermediate hosts.hemocytes from schistosome-resistant and schistosome-susceptible biomphalaria glabrata differ fundamentally in their behavior towards an invading parasite. when the schistosome infects a resistant snail host it is quickly surrounded by hemocytes, encapsulated and destroyed. hemocytes from susceptible hosts fail to kill the parasite. to detect the differences between these two host phenotypes, we used differential-display reverse-transcription pcr (ddrt-pcr), based on rna extracted from isolated ...200111411951
refractoriness of host haemocytes to parasite immunosuppressive factors as a putative resistance mechanism in the biomphalaria glabrata-echinostoma caproni system.in contrast to the growing knowledge accumulated on plant resistance to pathogens, mechanisms of parasite resistance largely remain to be elucidated in animal species. in the present study we investigated mechanisms underlying resistance/susceptibility in the snail-trematode system biomphalaria glabrata-echinostoma caproni. in particular, we compared the effect of the parasite excretory-secretory (e-s) products on the defence functions of haemocytes from 2 susceptible and 2 resistant snail strai ...200111444618
[freshwater snails of the campus of manguinhos, oswaldo cruz foundation, rio de janeiro, rj].a survey of freshwater gastropods of the campus of manguinhos, fundação oswaldo cruz, rio de janeiro, was carried out during the last two years aiming to compare the current species with those found at the beginning of this century. among 18 breeding sites in 880,000m2 of the surveyed area, 13 showed the following species: antillorbis nordestensis; biomphalaria glabrata; biomphalaria straminea; lymnaea columella; melanoides tuberculatus; physa cubensis; pomacea glauca and pomacea lineata. notabl ...200111460215
hematopoietic tissue allografts in biomphalaria glabrata (mollusca: pulmonata) induce humoral immunity to schistosoma mansoni.we examined a potential mechanism for adoptively transferred resistance against schistosoma mansoni in schistosome-susceptible snails receiving allografts of the hematopoietic amebocyte-producing organ (apo) from a schistosome-resistant strain of biomphalaria glabrata. susceptible nih albino snails first were implanted with the apo from resistant salvador strain donors. at 14 days post-implantation, cell-free plasma was isolated from apo recipients and injected into a second group of nih albino ...200111472778
sequential histological changes in biomphalaria glabrata during the course of schistosoma mansoni infection.biomphalaria glabrata, highly susceptible to schistosoma mansoni, were seen to shed less and less cercariae along the time of infection. histological examination kept a close correlation with this changing pattern of cercarial shedding, turning an initial picture of no-reaction (tolerance) gradually into one of hemocyte proliferation with formation of focal encapsulating lesions around disintegrating sporocysts and cercariae, a change that became disseminated toward the 142nd day post miracidial ...200111500778
screening of malian medicinal plants for antifungal, larvicidal, molluscicidal, antioxidant and radical scavenging activities.a total of 78 different extracts from 20 medicinal plants belonging to 14 plant families from mali were tested for their antifungal, larvicidal, molluscicidal, antioxidant and radical scavenging activities. dichloromethane, methanol, water and ethanol extracts were used. tlc autobiography for antifungal activity was run with cladosporium cucumerinum and candida albicans. extracts were also tested on the larvae of the mosquitoes aedes aegypti, anopheles gambiae and culex quinquefasciatus. mollusc ...200111507731
involvement of nitric oxide in killing of schistosoma mansoni sporocysts by hemocytes from resistant biomphalaria glabrata.in strains of the snail biomphalaria glabrata (gastropoda) that are resistant to the parasite schistosoma mansoni (trematoda), hemocytes in the hemolymph are responsible for elimination of s. mansoni sporocysts. the defensive role of reactive nitrogen species was investigated in in vitro interactions between hemocytes derived from the resistant 13-16-r1 strain of b. glabrata and the parasite. the nitric oxide synthase (nos) inhibitor n(omega)-nitro-l-arginine methylester (l-name) and the nitric ...200111534641
larval schistosoma mansoni excretory-secretory glycoproteins (esps) bind to hemocytes of biomphalaria glabrata (gastropoda) via surface carbohydrate binding receptors.flow cytometric analysis of circulating blood cells (hemocytes) of biomphalaria glabrata, molluscan intermediate host of schistosoma mansoni, revealed the presence of 2 overlapping hemocyte subpopulations, designated r1 and r2. r1 hemocytes are characterized by their smaller size, reduced granularity, and the presence of the bgh1 surface epitope, whereas r2 cells are larger, more granulated, and generally lack the bgh1 cell marker. both hemocyte subpopulations bound fluorescent dye (oregon green ...200111534642
the c.e.b.a.s.-aquarack project: the laboratory prototype and first results of the scientific frame program.the paper explains the basic conception of a "closed equilibrated biological aquatic system" (c.e.b.a.s.) incorporated in a aquarack as a research tool for zoological, botanical and interdisciplinary research in space biology and describes the construction principle of laboratory prototype consisting of a modular habitat for aquatic animals a semi-biological/physical water recycling system and a computerized control unit. further on the running scientific frame program in which as well five germ ...199211541194
novel laboratory approaches to multi-purpose aquatic bioregenerative closed-loop food production systems.based on the construction principle of the closed equilibrated biological aquatic system (c.e.b.a.s.) two novel combined animal-plant production systems were developed in laboratory scale the first of which is dedicated to mid-term operation in closed state up to two years. in principle both consist of the "classic" c.e.b.a.s. subcomponents: animal tank (zoological component), plant cultivators (botanical component), ammonia converting bacteria filter (microbial component) and data acquisition/c ...201311541608
an aquatic ecosystem in space.the closed equilibrated biological aquatic system (cebas) mini-module experiment was designed to study aquatic ecosystem performance within a middeck locker on the space shuttle. cebas was flown aboard sts-89 in january 1998 with a population of four pregnant xiphophorus helleri female fish and eleven adult biomphalaria glabrata snails in the first compartment and 200 juvenile x. helleri and 48 adult and juvenile b. glabrata in the second compartment. a plant compartment contained eleven snails ...199911543037
the c.e.b.a.s.-minimodule: behaviour of an artificial aquatic ecological system during spaceflight.the c.e.b.a.s.-minimodule, a closed aquatic ecosystem integrated into a middeck locker and consisting of a zoological (animal tanks), a botanical (plant bioreactor), a microbial (bacteria filter) and an electronic component (data acquisition/control system) was flown on the sts-89 spaceshuttle mission in january 1998 for 9 days. preflight the plant bioreactor was loaded with 53 g of ceratophyllum demersum (coontail) and the animal tanks with 4 adult pregnant females of the fish, xiphophorus hell ...200011543160
protein kinase c regulation of cell spreading in the molluscan biomphalaria glabrata embryonic (bge) cell line.cellular adhesion and spreading are critical components involved in the processes of cell and tissue development, and immune responses in molluscs, but at present, little is known regarding the signaling pathways involved in these basic cellular functions. in the present study, the molluscan biomphalaria glabrata embryonic (bge) cell line was used as an in vitro model to study the signal transduction pathways regulating molluscan cell adhesion and spreading behavior. western blot analysis using ...200111583819
possible competitive displacement of planorbids by melanoides tuberculata in minas gerais, brazil.several species of snails, including pomacea haustrum, marisa cornuarietis and helisoma duryi, have been identified as probable competitors and/or predators of planorbid intermediate hosts of schistosoma. during the last few years, studies carried out in the caribbean region have shown reductions and even disappearances of populations of biomphalaria glabrata and b. straminea in breeding places where the snail melanoides tuberculata was introduced. observations made over a period of 10 years in ...200111586446
freshwater snails and schistosomiasis mansoni in the state of rio de janeiro, brazil: i-- metropolitan mesoregion.in order to elaborate a planorbid chart of the state of rio de janeiro a survey of freshwater gastropods in the metropolitan mesoregion of this state was performed and revealed the occurrence of 20 species: antillorbis nordestensis (lucena, 1954); biomphalaria glabrata (say, 1818); biomphalaria schrammi (crosse, 1864); biomphalaria straminea (dunker, 1848); biomphalaria tenagophila (orbigny, 1835); burnupia sp.; drepanotrema anatinum (orbigny, 1835); drepanotrema cimex (moricand, 1839); drepanot ...200111586447
[the model of statoconia distribution in the gravity receptors of shells in ontogenesis].based on the experimental data of wiederhold et al., analyzed was distribution of statoconia in gravireceptors of biomphalaria glabrata and aplysia californica in ontogenesis. a mathematical model of size distribution of statoconia in statocyst biomphalaria glabrata in ontogenesis has been developed. growth of statoconia in size is described as a process of crystallization from solution. hypothetically, redistribution of statoconia in ontogenesis is determined by generation of new statoconia and ...200111589158
description of the adult worms of a new brazilian isolate of echinostoma paraensei (platyhelminthes:digenea) from its natural vertebrate host nectomys squamipes by light and scanning electron microscopy and molecular analysis.echinostoma paraensei lie and basch, 1967 (echinostomatidae:platyhelminthes), a 37 collar spine echinostome of the "revolutum group", has been used extensively as a model organism to study the interactions of digenetic trematodes with both their snail and vertebrate hosts. this worm was first isolated from the snail biomphalaria glabrata from belo horizonte (bh isolate), minas gerais state, brazil, by lie and basch [j parasitol (1967) 53:1192-1199]. the natural definitive host for the bh isolate ...200111688891
biological aspects of a new isolate of echinostoma paraensei (trematoda: echinostomatidae): susceptibility of sympatric snails and the natural vertebrate host.a new isolate of echinostoma paraensei (lie & basch, 1967) was obtained from a natural vertebrate host, the water rat nectomys squamipes. relationships with sympatric snails, biomphalaria glabrata; physa marmorata and lymnaea columella, as well as allopatric snails and the definitive hosts n. squamipes, mus musculus, rattus norvegicus, mesocricetus auratus and birds were investigated. e. paraensei developed in all sympatric snail species following exposure to one or five miracidia. p. marmorata ...200111688893
axenic culture of schistosoma mansoni sporocysts in low o2 environments.recent successes in culturing intramolluscan larval stages of schistosoma mansoni have relied on synxenic culture with a cell line (bge) developed from embryos of a molluscan host biomphalaria glabrata. to further facilitate progress toward control of schistosomiasis, a system for axenic in vitro culture of the parasite has now been developed. when culture media were preconditioned by bge cells, sporocysts lived longer in vitro and produced more offspring. because bge-derived components could be ...200111695386
evolutionary relationships and biogeography of biomphalaria (gastropoda: planorbidae) with implications regarding its role as host of the human bloodfluke, schistosoma mansoni.the wide geographic distribution of schistosoma mansoni, a digenetic trematode and parasite of humans, is determined by the occurrence of its intermediate hosts, freshwater snails of the genus biomphalaria (preston 1910). we present phylogenetic analyses of 23 species of biomphalaria, 16 neotropical and seven african, including the most important schistosome hosts, using partial mitochondrial ribosomal 16s and complete nuclear ribosomal its1 and its2 nucleotide sequences. a dramatically better r ...200111719572
the relationship between schistosoma mansoni and biomphalaria glabrata: genetic and molecular approaches.biomphalaria glabrata is a major intermediate host for the helminth parasite schistosoma mansoni. beginning in the mid-20th century, studies were carried out with this snail species to identify the immunological and genetic components that might be involved in controlling schistosome development. a number of genetically well-defined snail stocks were derived as a direct result of these studies and have since played major roles in helping investigators to identify important cellular and humoral c ...200111769281
molecular approaches in the study of biomphalaria glabrata--schistosoma mansoni interactions: linkage analysis and gene expression profiling.gene mapping and the generation of linkage groups are fundamental to an understanding of the organization and relationships of genes and marker sequences, providing a framework with which to investigate their association with traits of interest. the abundance of techniques available for generating polymorphic molecular markers, and recent advances in high throughput screening, have allowed the extension of map analysis to the tropical freshwater snail biomphalaria glabrata, an important intermed ...200111769282
further characterization of passively transferred resistance to schistosoma mansoni in the snail intermediate host biomphalaria glabrata.a heat-labile plasma factor from genetically resistant 10-r2 biomphalaria glabrata snails confers passively transferred resistance (ptr) to schistosoma mansoni when injected into susceptible snails within 24-hr of exposure to miracidia. however, no additional details on ptr have emerged since the initial 1984 report, nor has the plasma resistance factor been characterized. in the present study, new information is provided on the occurrence of resistance factor in plasma of additional types of sn ...200111780822
biological characteristics of praziquantel-resistant and -susceptible isolates of schistosoma mansoni.if there is a change in the biological characteristics of schistosomes associated with the development of resistance to praziquantel, this could affect the transmission and pathology of the diseases they cause. to investigate this possibility, the host-parasite relationships of five praziquantel-resistant and five praziquantel-susceptible isolates of schistosoma mansoni were compared in biomphalaria glabrata snails and outbred cd(1) albino mice. whether praziquantel-resistant or -susceptible, al ...200111784425
parasite-responsive igsf members in the snail biomphalaria glabrata: characterization of novel genes with tandemly arranged igsf domains and a fibrinogen domain.two novel genes of the immunoglobulin superfamily (igsf), frep3 and frep7, are reported from the snail biomphalaria glabrata, a prominent intermediate host of the human parasite schistosoma mansoni. they resemble other b. glabrata genes that encode fibrinogen-related proteins (freps), but differ in that they encode proteins with two tandemly arranged igsf domains followed by a c-terminal fibrinogen domain. freps are hemolymph proteins that increase in abundance following exposure to a digenetic ...200111797103
[abundance and infection of biomphalaria glabrata with schistosoma glabrata in the state of rio de janeiro, brazil].to investigate the spatial distribution, abundance and natural schistosomiasis infection levels in the snail biomphalaria glabrata, the intermediate host of schistosoma mansoni in an area of the state of rio de janeiro, brazil.200111799465
mixed strain schistosome infections of snails and the evolution of parasite virulence.mathematical models often propose that within-host competition between parasites can be a major factor in the evolution of increased parasite virulence. kin selection predicts that as the coefficient of relatedness between infecting parasites decreases, the benefits of competition to individual genotypes increases. thus where parasites can adjust their behaviour in response to current conditions, higher virulence is predicted in multiple genotype infections. there is limited experimental data, h ...200211811801
aquatic modules for bioregenerative life support systems based on the c.e.b.a.s. biotechnology [correction of biotechnilogy].most concepts for bioregenerative life support systems are based on edible higher land plants which create some problems with growth and seed generation under space conditions. animal protein production is mostly neglected because of the tremendous waste management problems with tetrapods under reduced weightlessness. therefore, the "closed equilibrated biological aquatic system" (c.e.b.a.s.) was developed which represents an artificial aquatic ecosystem containing aquatic organisms which are ad ...200611858270
fine-scale population structure and dispersal in biomphalaria glabrata, the intermediate snail host of schistosoma mansoni, in venezuela.biomphalaria glabrata is the main intermediate host of schistosoma mansoni in america and one of the most intensely studied species of freshwater snails, yet very little is known about its population biology. here, we used seven highly polymorphic microsatellite loci to analyse genetic diversity in the valencia lake basin, which represents the core of the endemic area for schistosomiasis in venezuela. populations were sampled at short spatial scale (a few kilometres), both inside the lake and in ...200211975704
[influence of hydrocortisone on schistosoma mansoni development in biomphalaria glabrata].the effect of hydrocortisone on the development of bh strain of s. mansoni in b. glabrata snails is evaluated. snails in a randomly chosen group were submitted to hydrocortisone during four days. in the second day of hydrocortisone exposure, the snails were exposed, each, to ten s. mansoni miracidia. another group, not treated with hydrocortisone, was exposed to miracidia and observed in the same manner. various items of data were observed: the infection rate, survival time, prepatent period and ...200212011923
a new method for fixing biomphalaria glabrata for histologic studies, using shell perforation.a new technique for fixation of biomphalaria glabrata for histologic studies is described. it consists in performing several external holes in the shell, before placing the entire snail into the fixative. it is a very practical and quick procedure that showed excellent results when compared to the usual techniques.200212016457
monoamines in the albumen gland, plasma, and central nervous system of the snail biomphalaria glabrata during egg-laying.the potential role of selected biogenic monoamines and related compounds in the reproductive physiology of the freshwater snail biomphalaria glabrata was investigated. extracts of the albumen gland (ag), plasma, and central nervous system (cns) were subjected to high pressure liquid chromatography with electrochemical detection (hplc-ed), and under the extraction and separation conditions employed the following amines were detected: tyrosine, dihydroxyphenylalanine (dopa), dopamine, and tryptoph ...200212020657
interaction between the intermediate host of schistosomiasis in brazil biomphalaria glabrata (planorbidae) and a possible competitor melanoides tuberculata (thiaridae): i. laboratory experiments.the biological control of biomphalaria glabrata, intermediate host of schistosoma mansoni, is one the accepted options to fight schistosomiasis. one of the most promising candidates to control b. glabrata is the snail melanoides tuberculata, a potential competitor. however, the mechanisms of interaction between the two species are not clear. our objective is to determine if m. tuberculata indeed compete with b. glabrata, using two laboratory experiments. in experiment 1, we tested the effect of ...200212048567
nitric oxide limits parasite development in vectors and in invertebrate intermediate hosts.nitric oxide (no) possesses antiparasitic effects on both protozoa and metazoa in vertebrate definitive and intermediate hosts. inducible no limits parasite development also in rhodnius prolixus and anopheles stephensi, the natural vectors of human trypanosomiasis and malaria respectively, and in the snail biomphalaria glabrata, a natural invertebrate intermediate host of human schistosomiasis. therefore, no limits trypanosoma, plasmodium, and schistosoma development at all stages of the parasit ...200212049194
schistosoma mansoni sporocysts in culture: host plasma hemoglobin contributes to in vitro oxidative stress.the initiation and promotion of sporocyst propagation and subsequent production of cercariae by intramolluscan larval stages of digenic trematodes are thought to depend on mollusc-derived factors. the ability to investigate this using in vitro cultures of schistosoma mansoni sporocysts has been impeded by the fact that plasma from the host, biomphalaria glabrata, becomes toxic to the parasite in long-term cultures. the present study identifies hemoglobin as the plasma component responsible for t ...200212053954
distribution of schistosome infections in molluscan hosts at different levels of parasite prevalence.biomphalaria glabrata snails infected with schistosoma mansoni were collected during consecutive seasons from a site in brazil known to have a very high percentage of infected snails. schistosoma mansoni cercariae from single snails were used to infect individual mice, and the recovered adult worms were genetically assessed using a mtvntr marker. the number of unique parasite genotypes found per snail was compared to expected abundance values, based on the infection prevalence at the site, to de ...200212053991
toxicology of a potential molluscicide derived from the plant solanum xanthocarpum: a preliminary study.a potential molluscicidal extract, obtained from the indigenous chinese plant solanum xanthocarpum (schrad. and wendl), was tested for toxicity against snails and fish in static, acute-toxicity tests. the extract had a significant effect on mature and young snails of the amphibious asian freshwater prosobranch oncomelania hupensis (gredler) and also on mature specimens of the freshwater pulmonate snails biomphalaria glabrata (say) and lymnaea stagnalis (linnaeus). the minimum dose that produced ...200212061979
genetic variability of the main intermediate host of the schistosoma mansoni in brazil, biomphalaria glabrata (gastropoda: planorbidae) assessed by ssr-pcr.the genetic variability of brazilian biomphalaria glabrata populations was studied using ssr-pcr. this technique is a variant of the polymerase chain reaction (pcr), which consists of using a single primer directed towards microsatellite regions under high stringency reaction conditions. twenty snails of each population from eight distant brazilian localities were analyzed. morphology and pcr-rflp were used for previous specific identification of the snails. bands generated after gel electrophor ...200212062789
toxicity of lapachol and isolapachol and their potassium salts against biomphalaria glabrata, schistosoma mansoni cercariae, artemia salina and tilapia nilotica.the toxicity of soluble derivatives (potassium salt) of lapachol and isolapachol in different stages of the life cycle of schistosoma mansoni is evaluated. the potassium salts of isolapachol and lapachol showed significant molluscicidal activity against the adult snail (lc90<7 ppm) and snail egg masses (lc90<3 ppm). cercaricidal assays revealed strong activities for both compounds. lethality assays against brine shrimp eggs (artemia salina leach) indicated very high toxicity for the potassium sa ...200212062792
molluscicidal activity of plants from puerto rico.overall, 173 tropical plants from 72 different families, collected from the north-western and western regions of puerto rico, were screened for their molluscicidal properties against biomphalaria glabrata, the intermediate host of schistosoma mansoni. six plant extracts were effective at 50 ppm. the two most effective extracts were those from the leaves of didymopanax morototoni (araliaceae) and mammea americana (guttiferae), which, at 50 ppm, killed all snails after 24 h of exposure and a day f ...200212080983
serine protease and phenoloxidase activities in hemocytes of biomphalaria glabrata snails with varying susceptibility to infection with the parasite schistosoma mansoni.the snail biomphalaria glabrata possesses hemocytes, which are supposed to interact with the larval stages of the human parasite schistosoma mansoni. we describe trypsin-like serine protease(s) and phenoloxidase activities in lysates from these hemocytes. both enzymes have activity optima around ph 9.5. the serine protease was inhibited by edta, pmsf, antipain and aprotinin, and the phenoloxidase activity by diethydithiocarbamate. by comparison, the serine protease activity in secretions of s. m ...200212107469
resistance to cadmium and parasite infection are inversely related in two strains of a freshwater gastropod.phenotypes that are either resistant or susceptible to infection by the trematode parasite schistosoma mansoni exist in the tropical freshwater snail biomphalaria glabrata. we tested the hypothesis that a cost of parasite resistance in b. glabrata is greater sensitivity to cadmium toxicity, using parasite-resistant and parasite-susceptible strains exposed to cadmium in the laboratory. survival analysis showed that time to death for cadmium was significantly shorter in eggs, juveniles, and adults ...200212109739
the symbiont capsaspora owczarzaki, nov. gen. nov. sp., isolated from three strains of the pulmonate snail biomphalaria glabrata is related to members of the mesomycetozoea.while investigating the resistance of some strains of biomphalaria glabrata to infection with schistosoma mansoni, a unicellular eukaryotic symbiont was noted in the snail haemolymph. it was similar in appearance to nuclearia sp. reported from b. glabrata. sequences comprising the 18s, its1, 5.8s, its2 and the beginning of the 28s rdna gene regions were obtained from symbionts isolated from three strains of b. glabrata, and compared with the same sequences obtained from a culture of nuclearia sp ...200212117501
in vitro cultivation of cells from ovotestis tissue of pigmented biomphalaria glabrata.cells derived from ovotestis tissue of pigmented biomphalaria glabrata, puerto rican strain were cultured in double diluted git medium supplemented with modification of amino acids components of pigmented b. glabrata, ovotestis and mid-gut region and 3% inactivated fetal calf serum. as a result, two types of cells, epithelial and fibroblastic like cells increased in number during the cultivation. it seem that the medium used in this study is a suitable medium for cultivation of cells from ovotes ...200212125924
molluscicidal activity against biomphalaria glabrata of brazilian cerrado medicinal plants.alcoholic extracts of six brazilian cerrado medicinal plants were evaluated for their molluscicidal activity against biomphalaria glabrata, intermediate host of schistosomiasis. stryphnodendron polyphyllum bark extract, rich in condensed tannins, was the most promising as molluscicide.200212165343
the molluscicidal activity of niclosamide (bayluscide wp70(r)) on melanoides tuberculata (thiaridae), a snail associated with habitats of biomphalaria glabrata (planorbidae).the aim of this study was to determine the toxicity of niclosamide (bayluscide (r)) on melanoides tuberculata and biomphalaria glabrata under laboratory conditions. the latter species is the intermediate host of schistosoma mansoni (sambon 1917). m. tuberculata was successfully used as competitor of b. glabrata in biological control programs in french west indies. both molluscicide and biological control using m. tuberculata have proved to be successful in reducing the population density of b. g ...200212219145
genetic differentiation, dispersal and mating system in the schistosome-transmitting freshwater snail biomphalaria glabrata.biomphalaria glabrata is the main intermediate host of schistosoma mansoni in america and one of the most intensely studied species of freshwater snail, yet very little is known about its population biology. here, we used seven highly polymorphic microsatellite loci to analyse genetic diversity in populations from three regions (lesser antilles, venezuela and southern brazil). considerable genetic variation was detected, with an average (s.d.) h(0) = 0.32 (0.24). more diversity per population wa ...200212242641
evolutionary history and phylogeography of the schistosome-vector freshwater snail biomphalaria glabrata based on nuclear and mitochondrial dna sequences.the phylogeography of the freshwater snail biomphalaria glabrata remains poorly known, although this species is the major vector of schistosomiasis in the new world. it was here investigated in south america and the lesser antilles, based on partial mitochondrial large ribosomal subunit (16s rdna) and nuclear internal transcribed spacer-2 (its-2) gene sequences. sampling included 17 populations from a large part of the current geographic range of the species (brazil, venezuela and lesser antille ...200212242642
embryonic development of the freshwater snail biomphalaria glabrata under microgravity conditions (sts-89 mission).the embryonic development of the fresh-water snail biomphalaria glabrata was examined under microgravity-conditions and compared with the ground control and standard embryos, putting special emphasis on the shell formation. the process of shell formation may be particularly sensitive to the change of gravitational forces. the project aimed at determining whether the processes of mineralization during the formation of the exoskeleton in the growing snail embryo take place normally under micrograv ...200112365448
the influence of hydrocortisone on cellular defence mechanisms of biomphalaria glabrata.since the internal defense system of mollusks consists of cellular and humoral mechanisms, we examined the role of hydrocortisone in mollusks defense cells and the influence of this steroid on the development of schistosoma mansoni in its intermediary host. hydrocortisone had an immunosuppressive action in biomphalaria glabrata, as reflected in the reduced number of defense cells and the altered cell physiology. histopathological analysis showed that hydrocortisone facilitated the intramolluscan ...200212386715
schistosomiasis mansoni in areas of low transmission: epidemiological characterization of venezuelan foci.severe schistosomiasis is a rare event in venezuela nowadays, after a successful national campaign by the schistosomiasis control program. unfortunately, this program has practically disappeared, and snail surveillance in field is not a priority, anymore. thus, schistosomiasis has become a neglected disease in this country. however, surveys in different populations from the endemic area have shown particular epidemiological features described herein. in five communities we evaluated 2,175 person ...200212426585
sequencing of simple sequence repeat anchored polymerase chain reaction amplification products of biomphalaria glabrata.simple sequence repeat anchored polymerase chain reaction amplification (ssr-pcr) is a genetic typing technique based on primers anchored at the 5' or 3' ends of microsatellites, at high primer annealing temperatures. this technique has already been used in studies of genetic variability of several organisms, using different primer designs. in order to conduct a detailed study of the ssr-pcr genomic targets, we cloned and sequenced 20 unique amplification products of two commonly used primers, c ...200212426589
polymerase chain reaction and restriction fragment length polymorphism of cytocrome oxidase subunit i used for differentiation of brazilian biomphalaria species intermediate host of schistosoma mansoni.the intermediate hosts of schistosoma mansoni, in brazil, biomphalaria glabrata, b. tenagophila and b. straminea, were identified by restriction fragment length polymorphism analysis of the mitochondrial gene cytochrome oxidase i (coi). we performed digestions with two enzymes (alui and rsai), previously selected, based on sequences available in genbank. the profiles obtained with rsai showed to be the most informative once they were polymorphic patterns, corroborating with much morphological da ...200212426594
genetic markers between biomphalaria glabrata snails susceptible and resistant to schistosoma mansoni infection.the analysis of the genetic variability related to susceptibility to schistosoma mansoni infection in the vector of the genus biomphalaria is important in terms of a better understanding of the epidemiology of schistosomiasis itself, the possible pathological implications of this interaction in vertebrate hosts, and the formulation of new strategies and approaches for disease control. in the present study, the genetic variability of b. glabrata strains found to be resistant or susceptible to s. ...200212426595
antigenic community between schistosoma mansoni and biomphalaria glabrata: on the search of candidate antigens for vaccines.we have previously confirmed the presence of common antigens between schistosoma mansoni and its vector, biomphalaria glabrata. cross-reactive antigens may be important as possible candidates for vaccine and diagnosis of schistosomiasis. sera from outbred mice immunized with a soluble biomphalaria glabrata antigen (sbga) of non-infected b. glabrata snails recognized molecules of sbga itself and s. mansoni awa by western blot. recognition of several molecules of the sbga were inhibited by pre-inc ...200212426602
parasite-susceptibility phenotypes of f1 biomphalaria glabrataprogeny derived from interbreeding schistosoma mansoni-resistant and -susceptible snails.in an effort to investigate the 'flow' of parasite-resistance genes through laboratory snail populations, we determined the susceptibility of progeny snails from freely interbreeding parasite-susceptible and parasite-resistant parents. five parental populations of biomphalaria glabrata were used to generate the progeny snails. three of them contained different proportions of schistosoma mansoni-susceptible albino snails (nmri stock) and s. mansoni-resistant pigmented snails (bs-90), while single ...200312489007
gene expression changes in schistosoma mansoni sporocysts induced by biomphalaria glabrata embryonic cells.biomphalaria glabrataembryonic (bge) cells have been shown to provide favourable environmental conditions for the development of schistosoma mansoni sporocysts. we investigated the effect of bge excretory-secretory products on metabolic activity and gene transcription in s. mansoni mother sporocysts. using the differential-display technique, we identified several sporocyst transcripts regulated by exposure to bge soluble components. research in databases indicated that six of the eight different ...200312489010
emergence of cercariae of echinostoma caproni and schistosoma mansoni from biomphalaria glabrata under different laboratory conditions.release of echinostoma caproni cercariae and schistosoma mansoni from experimentally infected biomphalaria glabrata snails maintained under different laboratory conditions was studied. infected snails were isolated individually for 1 h in stender dishes containing 5 ml of artificial spring water and the number of cercariae released during this time was recorded. of numerous conditions tested, the addition of lettuce, the use of water conditioned by b. glabrata snails and a temperature of 35 degr ...200212498644
in vitro and in vivo encystment of the cercariae of echinostoma caproni.in vitro and in vivo studies were conducted on the cercariae of echinostoma caproni. of the 15 media tried, 2 resulted in effective in vitro encystment in petri dish cultures maintained at 23 +/- 1 c. they were a locke's--artificial springwater (asw) (1:1) medium (67% encystment) and a biomphalaria glabrata embryonic cell line medium (23% encystment). to obtain large numbers of in vitro--formed cysts, finger bowl cultures containing 40 ml of the locke's-asw (1:1) medium were used at 23 +/- 1 c. ...200212537105
Refresh
firstprev
12345678910...
nextlast
Displaying items 801 - 900 of 1375