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identification of a schistosoma mansoni sporocyst excretory-secretory antioxidant molecule and its effect on superoxide production by biomphalaria glabrata hemocytes.excretory-secretory (e-s) products obtained during in vitro schistosoma mansoni miracidium-to-sporocyst transformation were found to contain a 108-kda polypeptide capable of scavenging both exogenously produced and m-line biomphalaria glabrata hemocyte-derived superoxide (o2-) anions. separation of crude transformation e-s products using hplc and ion exchange chromatography resulted in the separation of two isoforms of the 108-kda molecule. using an in vitro phagocytosis assay, both isoforms wer ...19911664845
schistosoma mansoni: use of a cloned ribosomal rna gene probe to detect restriction fragment length polymorphisms in the intermediate host biomphalaria glabrata.adult susceptibility of biomphalaria glabrata to schistosoma mansoni infection is controlled by simple mendelian genetics. in this study a molecular approach was used to determine the degree of genetic variation between well-defined lines of b. glabrata which are either resistant (10-r2) or susceptible (m-line) to s. mansoni infection. a cloned probe psm389, which contains part of the s. mansoni small ribosomal rna gene and a portion of the nontranscribed spacer was found to cross-hybridize with ...19911680745
schistosoma mansoni and biomphalaria glabrata have some common epitopes. i. common epitopes are present on the surface of early stages of s. mansoni.1. the presence of snail and glycocalyx antigens in the schistosoma mansoni cercarial surface and their permanence throughout development in vitro and in vivo was investigated. 2. rabbit antisera raised against two fractions of glycocalyx released from cercariae and biomphalaria glabrata soft tissues or haemolymph were obtained. 3. all four antisera bound to cercariae and schistosomula kept in vitro or in vivo for up to 24 hr. 4. no binding to schistosomula kept in vivo for 5 days or longer was ...19911726079
isolation and functional characterization of snail hemocyte-modulating polypeptide from primary sporocysts of schistosoma mansoni.infection with larval trematodes has been shown to inhibit several snail-host defences, including hemocyte phagocytosis, cytotoxicity, motility, and adherence. certain plasma factors which mediate snail defence responses, and which may be produced by host hemocytes, also appear to be altered by these parasites. in this study we present protocols for the isolation of 2 proteins from larval schistosoma mansoni excretory-secretory (es) products and detail the effects of these components on biomphal ...19911775150
thermal preferences of resistant and susceptible strains of biomphalaria glabrata (gastropoda) exposed to schistosoma mansoni (trematoda).the thermal preferences of two strains of the snail biomphalaria glabrata, one resistant to, and one susceptible to, the parasite schistosoma mansoni were determined in an aquatic thermal gradient. snails were tested without exposure to the parasite, and 2 h and 5 weeks after exposure to trematode miracidia. the mean temperature selected by susceptible strain snails 2 h post-exposure tended to be lower than that of unexposed controls, although this was not statistically significant. in this stra ...19911780172
[effects of eugenol and derivatives on biomphalaria glabrata].biomphalaria glabrata snails and egg-masses were exposed, for six to twenty-four hours to concentrations of 1, 10, 100 and 1000 ppm of eugenol, o-methyleugenol, o-benzyleugenol and dehydrodieugenol. only at 10 ppm o-benzyleugenol enhanced mortality of snails and egg-masses. the other substances showed ovicidal and molluscicidal activity only at 100 and 1000 ppm concentrations, causing a significant cardiac frequency reduction in snails after 6 to 24 hours of exposure as well as perduring low car ...19911844101
[repopulation of breeding habitats of biomphalaria glabrata after treatment with niclosamide].experiments were undertaken both in the laboratory and in the field between 1980-1984 to evaluate the causes of repopulation of breeding places of biomphalaria glabrata following treatment with niclosamide. laboratory bioassays showed that the susceptibility to emulsifiable niclosamide of b. glabrata collected monthly from an irrigation ditch system varied during the year. lethal concentrations (lc90) ranged between 0.15 mg/l-1 and 0.60 mg/l-1. statistically significant differences (alpha = 0.01 ...19911844951
physiologic studies of snail-schistosome interactions and potential for improvement of in vitro culture of schistosomes.despite extensive efforts to develop suitable media for rearing the intramolluscan stages of schistosomes, successful in vitro culture of these parasites remains elusive. recent 31p nmr studies demonstrated that the levels of free phospholipids, particularly phosphatidylcholine, in the digestive gland of the snail, biomphalaria glabrata, were dramatically reduced when the host was infected with schistosoma mansoni. it was speculated that absorption of host phosphatides may be an important source ...19911869492
[relationship between the pathogenicity of schistosoma mansoni in mice and the susceptibility of the vector mollusc. i. cercariae infectivity and worm burden].the possible influence of the immune mechanisms of the molluscs on the development of the sporocysts and the resultant behavior of the adult worm in the vertebrate host were studied. two strains of schistosoma mansoni (bh and sj) were used. these were genetically selected for their susceptibility and maintained, respectively, in biomphalaria glabrata and biomphalaria tenagophila, the natural invertebrate hosts. experimental groups of mice infected with cercariae proceeding from the two species o ...19911820625
[identification of a new focus of schistosoma mansoni. (municipality of nova lima, mg, brazil].the detection of a new transmission focus of schistosomiasis in nova lima town, minas gerais state, brazil, is reported. the search of snail intermediate hosts in banqueta do bananal a small locality of boa vista neighbourhood detected 356 specimens of biomphalaria glabrata, with a infection rate of 8.4%. in hundred-sixty-two patients stool examinations (kato-katz method) were done, showing ninety-one patients with eggs of schistosoma mansoni in their feces. the integrated action of local reside ...19911842844
lectin-binding properties of the surfaces of in vitro-transformed schistosoma mansoni and echinostoma paraensei sporocysts.as carbohydrates on the surfaces of sporocysts of digenetic trematodes may be targets of attack by the molluscan internal defense system, the lectin-binding patterns of living, in vitro-transformed sporocysts of schistosoma mansoni and echinostoma paraensei were characterized. schistosoma mansoni sporocysts specifically bound 8 and e. paraensei 6 of 11 lectins examined. sporocysts of the 2 species responded differently to 7 of the 11 lectins. lectins inhibitable by mannose, galactose, and n-acet ...19911919922
influence of the nontarget mollusc marisa cornuarietis on the hourly cercarial production of schistosoma mansoni from biomphalaria glabrata.a comparative study of hourly cercarial productivities of schistosoma mansoni from infected biomphalaria glabrata was carried out in the presence of either healthy b. glabrata (control) or healthy marisa cornuarietis (experimental). the results showed that, with m. cornuarietis, almost all the hourly cercarial productivities increased by a factor varying from 1.3 to 2.5 without modification of the shedding period.19911919935
[the use of the shell of the cashew nut, anacardium occidentale, as an alternative molluscacide].bioassays using hexanolic extracts of cashew nut shells, of anacardium occidentale, collected in ceará in 1972 (sample 1) and 1987 (sample 2) were undertaken with adult snails and egg masses of biomphalaria glabrata, b. tenagophila and b. straminea both in the laboratory and in the field. non extracted shells, 18.5 g, sample 1, were also tested with adult snails and egg masses of the three species. the toxicity of extract was tested with fish (poecilia reticulata) and tadpoles. the lethal concen ...19921342111
natural infection of wild rodents by schistosoma mansoni. parasitological aspects.the evaluation of the role of rodents as natural hosts of schistosoma mansoni was studied at the pamparrão valley, sumidouro, rj, with monthly captures and examination of the animals. twenty-three nectomys squamipes and 9 akodon arviculoides with a schistosomal infection rate of 56.5% and 22.2% respectively eliminated a great majority of viable eggs. with a strain isolated from one of the naturally infected n. squamipes, we infected 75% of simpatric biomphalaria glabrata and in 100% of albino mu ...19921343794
carbohydrate-binding plasma proteins from the gastropod biomphalaria glabrata: strain specificity and the effects of trematode infection.as lectins are believed to mediate non-self-recognition in molluscs, carbohydrate-binding proteins (cbp) from the circulating plasma of the gastropod biomphalaria glabrata were harvested by affinity chromatography using six different monosaccharides as ligands. pools of plasma were derived from b. glabrata of either the m line strain, which is susceptible to infection with the pr1 strain of the digenetic trematode schistosoma mansoni, or from the 13-16-r1 strain, which is resistant to infection. ...19921330758
immunosuppression in the definitive and intermediate hosts of the human parasite schistosoma mansoni by release of immunoactive neuropeptides.evidence supporting the concept that the parasitic trematode schistosoma mansoni may escape immune reactions from its vertebrate (man) or invertebrate (the freshwater snail biomphalaria glabrata) hosts by using signal molecules it has in common with these hosts was obtained by the following experiments. the presence of immunoactive proopiomelanocortin (pomc)-derived peptides [corticotropin (acth), beta-endorphin] in, and their release from, s. mansoni was demonstrated. coincubation of adult worm ...19921309957
immunoelectrophoretic study on common antigens of são lourenço da mata and belo horizonte strains of schistosoma mansoni adult worms and biomphalaria snails.immunoelectrophoretic studies on common antigens were carried out by using rabbits sera immunized against são lourenço da mata and belo horizonte strains of schistosoma mansoni adult worms and antigens of biomphalaria glabrata pigmented (jaboatão--pe); b. glabrata albino (belo horizonte--mg) and b. straminea (são lourenço da mata, pe). furthermore, the reverse approach was proceeded, namely, sera anti biomphalaria snails produced in rabbits were tested against both strains of schistosoma adult w ...19921284896
biological control of the snail intermediate hosts of schistosoma mansoni in martinique, french west indies.in martinique water-cress beds constituted the last transmission sites for schistosomiasis. the competitor snail, melanoides tuberculata, was introduced at the beginning of 1983 to a group of water-cress beds and eliminated the snail hosts, biomphalaria glabrata and b. straminea, in less than two years. following this first success, m. tuberculata was introduced to the other groups of beds which were inventoried at the beginning of the eighties. at the present time, b. glabrata and b. straminea ...19921519033
a municipal level approach to the management of schistosomiasis control in peri-peri, mg, brazil.a schistosomiasis control program was implemented between 1974/87 in peri-peri, mg (622 inhabitants). molluscicide (niclosamide) was applied at three monthly intervals in water sources with biomphalaria glabrata, and individuals eliminating schistosoma mansoni eggs in the feces were treated annually with oxamniquine. from 1974 to 1983 the control measures were undertaken by staff of the "rené rachou" research center fiocruz (cpqrr), and from 1984 to 1987 these measures were included in the capim ...19921342123
excretory-secretory products of echinostoma paraensei sporocysts mediate interference with biomphalaria glabrata hemocyte functions.miracidia of echinostoma paraensei were cultured in medium containing 14c-labeled amino acids, allowed to transform into sporocysts, and their excretory/secretory products (e-s) were collected and characterized by sodium dodecyl sulfate polyacrylamide gel electrophoresis and autoradiography. effects of e-s on hemocytes of biomphalaria glabrata were also assessed. e-s collected during day 1 of culture (e-s1) contained several polypeptides, none of which were labeled, suggesting that e-s1 are larg ...19921738052
intermediate hosts of schistosoma mansoni in brazil.the brazilian planorbidical chart is slowly but progressively been increased by new data. distribution of vector species of schistosoma mansoni, according to paraense, 1986, may be thus resumed: biomphalaria glabrata--delimited by parallels 13 and 21 degrees s and meridians 39 and 45 degrees w, area of greater dominance (southeast bahia, oriental hal of minas gerais and espírito santo). it is observed along the coast line of the states of sergipe, alagoas, pernambuco, paraiba and rio grande do n ...19921343914
miracidium of schistosoma mansoni: a macromolecular glycoconjugate as signal for the behaviour after contact with the snail host.1. the behaviour of the miracidium of schistosoma mansoni after contact with agar blocks containing biomphalaria glabrata snail conditioned water (scw) or its components, was studied. 2. "repeated investigation" was the most specific response at contact with the snail host. 3. fractionation and specific chemical treatment of scw revealed that this response was stimulated by a lysozyme sensitive glycoconjugate with a mol. wt greater than 300,000. 4. low molecular weight components of scw had no s ...19921348464
studies on common antigenicities between the belo horizonte strain, brazil of schistosoma mansoni eggs and biomphalaria snails by immunoelectrophoresis.immunoelectrophoretic studies of common antigenicities were carried out by using rabbit sera immunized against the belo horizonte strain of schistosoma mansoni eggs and crude antigens of biomphalaria snails and vice versa. with regard to common antigenicities between s. mansoni eggs and biomphalaria snails, s. mansoni eggs produced 4 to 5 bands with biomphalaria glabrata pigmentado, 3 to 4 bands with b. glabrata albino and only 1 band with b. straminea. in our laboratory, the infection rate of s ...19921381846
responses of echinostoma caproni miracidia to gravity, light, and chemicals.in a four-tube vertical system, echinostoma caproni miracidia exhibited a strong negative geotaxis which was dominated by a positive phototaxis. in horizontal chambers a positive phototactic response was also demonstrated. these miracidia showed a positive chemoresponse, as determined in phi-chambers, to glutamic and aspartic acids but not leucine. positive responses were also elicited to snail-conditioned water and sulfuric and acetic acids. ammonia, mg2+, and hcl produced no significant reacti ...19921399253
schistosoma mansoni infection in diapausing biomphalaria glabrata snails: studies of temperature and genetic influences on diapausing behavior.snails that are capable of undergoing diapause can circumvent unfavorable environmental conditions, including long periods of drought. studies were performed to investigate possible temperature and/or genetic factors that may trigger lamella formation and diapausing behavior. the influence of diapause in biomphalaria glabrata snails on susceptibility to schistosoma mansoni infection and levels of cercarial production was also investigated. rearing temperatures of 23 degrees c or higher did not i ...19921443349
early enhanced growth of the digestive gland of biomphalaria glabrata infected with schistosoma mansoni: side effect or parasite manipulation?we carried out a comparative study of the dynamics of the sporocyst population and the growth rate of the host habitat (digestive and genital gland) within the schistosoma mansoni/biomphalaria glabrata system during monomiracidial infections. the volume of the digestive gland increased sharply during the first 2 weeks of infection and then decreased at 2-4 weeks post-infection during the exponential growth phase of the sporocyst infrapopulation. the effects of the parasite on the development of ...19921495925
echinostoma paraensei and schistosoma mansoni: adherence of unaltered or modified latex beads to hemocytes of the host snail biomphalaria glabrata.hemocytes derived from a strain (13-16-r1) of biomphalaria glabrata resistant to schistosoma mansoni were significantly more likely to bind untreated latex beads than hemocytes from the schistosome-susceptible m line strain. beads preincubated in 13-16-r1 plasma were more readily bound by both 13-16-r1 and m line hemocytes than beads preincubated in m line plasma. beads preincubated in plasma derived from snails of either strain infected with the trematode echinostoma paraensei were more readily ...19921516670
spatial and energy compromise between host and parasite: the biomphalaria glabrata-schistosoma mansoni system.the development of a sporocyst infrapopulation of schistosoma mansoni within the biomphalaria glabrata snail is, from a spatial point of view, detrimental to the host's digestive-genital gland complex growth. for mono- and plurimiracidial infections, the digestive gland volumes are, respectively 51 and 24% of those of control snails. identical reduction of the infected genital gland volume (43% of controls) occurs in both cases. after the prepatent period, the ratio of parasite/digestive gland v ...19921563925
schistosoma mansoni infections in neonatal biomphalaria glabrata snails.in areas endemic for schistosomiasis, the population dynamics of the snail intermediate hosts have a direct effect on parasite transmission. the present study focused on the potential for neonatal biomphalaria glabrata snails to become infected with schistosoma mansoni and to produce cercariae under various conditions. it was found that snails as small as 0.74 mm in shell diameter could survive miracidial penetration and could release cercariae when as small as 1.6 mm in diameter. cercariae prod ...19921597786
identification, comparison and partial characterization of glycoproteins in the hemolymph of schistosoma mansoni (trematoda)-susceptible and resistant biomphalaria glabrata (gastropoda).1. glycoproteins in the plasma (cell-free hemolymph) of schistosoma mansoni-resistant and susceptible strains of biomphalaria glabrata were identified, characterized and compared using sodium dodecyl sulfate-polyacrylamide gel electrophoresis, electroblotting and a series of peroxidase-labeled lectins with different sugar specificities. 2. schistosome-resistant snails possessed at least three glycoproteins (70, 116, 205 kda) that were not present in plasma from susceptible snails. 3. sporocysts ...19921617939
biomphalaria glabrata: influence of calcium, lectins, and plasma factors on in vitro phagocytic behavior of hemocytes of noninfected or schistosoma mansoni-infected snails.in vitro phagocytosis of erythrocytes by hemocytes of b. glabrata, intermediate host of s. mansoni, is strongly influenced by calcium, several lectins, and plasma factors. our results indicate that two different mechanisms of non-self-recognition in b. glabrata may occur: (1) in the presence of calcium, phagocytosis occurs in noninfected and in infected snails without involvement of any other substances, and hemocytes of schistosome resistant as well as those of susceptible snails are able to re ...19921639158
the prolonged use of niclosamide as a molluscicide for the control of schistosoma mansoni.applications of niclosamide at three-monthly intervals were undertaken for 14 years in foci of biomphalaria glabrata in the water sources of peri-peri (capim branco, mg). all the residents of the area were submitted to an annual fecal examination (kato/katz) and those individuals eliminating schistosoma mansoni eggs were treated with oxamniquine. a malacological survey was undertaken at three-monthly intervals by means of ten scoops with a perforated ladle each ten metres along the two banks of ...19921342106
genetics of biomphalaria glabrata and its effect on the outcome of schistosoma mansoni infection.the genetics of the snail biomphalaria glabrata is better characterized than that of any other intermediate host of schistosomes of humans. using techniques of selective breeding, several snail stocks have been developed that consistently display resistant or susceptible phenotypes. investigators using these stocks have learned that several snail and parasite genes influence the course of parasite development. here, charles richards, matty knight and fred lewis discuss the importance of the snai ...199215463608
[preliminary trials of guaiacum officinale l. as a molluscicide].aqueous suspensions of fruit's pericarp, leaves, root's bark and seeds of guaiacum officinale were tested at different concentrations as molluscicide, cercaricide and piscicide. in the laboratory the suspension of fruit's pericarp produced 100% mortality for egg masses of b. glabrata at 100 ppm, for adult snails of biomphalaria glabrata, b. straminea and b. tenagophila at 20 ppm, for lebistes reticulatus (fishes) at 5 ppm and schistosoma mansoni's cercariae at 1 ppm. the ethanolic extract of fru ...19937997754
[relationship between the pathogenicity of schistosoma mansoni in mice and the susceptibility of the mollusk vector. ii. number of eggs in feces and number and size of granuloma in visceras].the influence of the susceptibility of the vector snails of s. mansoni on the development of the pathogenicity of the worm to the host was studied. off-spring of snails biomphalaria glabrata and biomphalaria tenagophila were used, selected with regard to the susceptibility to s. mansoni of the strains bh and sj trait, respectively. parenteral, f1, f2, f3 and f4 generation cercariae were used for the infection of swiss mice, which were killed eight weeks after infection. the number of eggs in the ...19937997811
schistosoma mansoni: comparison of cloned tropomyosin antigens shared between adult parasites and biomphalaria glabrata.rabbit antisera, raised against whole, homogenized hepatopancreas from uninfected biomphalaria glabrata, were used to screen a cdna library prepared from adult schistosoma mansoni. of 1.8 x 10(5) recombinants screened, 34 clones were specifically immunoreactive with the antisera. twenty of the clones were subcloned for further analysis, and 13 of the 20 were demonstrated to hybridize to a cdna probe encoding schistosome tropomyosin i (psmtm) at high stringency (xu et al. experimental parasitolog ...19937685709
the introduction of melanoides tuberculata (mollusca: thiaridae) to the island of saint lucia (west indies) and its role in the decline of biomphalaria glabrata, the snail intermediate host of schistosoma mansoni.a malacological survey was carried out in may 1992 in the whole hydrographic system of saint lucia 11 years after the end of a biological control programme to eliminate biomphalaria glabrata, the snail intermediate host of schistosoma mansoni. a competitor snail, melanoides tuberculata, was introduced to saint lucia in 1978 and field experiments in several habitats were conducted by prentice between 1978 and 1986. at the present time m. tuberculata is the most common freshwater snail in saint lu ...19938103624
[urban focus of schistosomiasis in a metropolitan area in a southeastern region of brazil].urban focus of schistosomiasis in an urban area of south-eastern, brazil. an active, urban focus of schistosomiasis in belo horizonte, mg, brazil is described. it is located in the "julien rien" park, a leisure area of 48,500 m2 created by the local administration in 1980 on the south side of city. snail captures were made over 10 years (1983-1992) resulting in the collection of 3,361 biomphalaria glabrata, ranging from 6.4 to 12.8 mm in diameter (mean = 9.3); 23 (0.7%) of these were found to be ...19938115836
schistosoma mansoni: analysis of an unusual infection phenotype in the intermediate host snail biomphalaria glabrata.snails from a b. glabrata stock, selected for nonsusceptibility to the nmri strain of s. mansoni, exhibited unusual schistosome infections, with multiple sporocysts prominent in the head-foot (foot-sporocysts). when f1 progeny from numerous crosses between well-defined susceptible (s) and resistant (r) parental snails were exposed, 60% of the infected snails also exhibited this unusual phenotype. f1 progeny from s x s snail crosses developed normal infections. foot-sporocysts usually developed m ...19938224090
compatibility of one brazilian and two venezuelan strains of schistosoma mansoni with various strains of biomphalaria glabrata.for evaluation of the degree of genetic heterogeneity in parasite and snail strains, the compatibility between biomphalaria glabrata and schistosoma mansoni from different geographical areas was studied. venezuelan snails from bárbula, manuare (areas of schistosome transmission) and tinaquillo (non-transmission area) and brazilian bh snails were exposed to infection with miracidia of both the venezuelan yt and sm strains and the brazilian bh strain of s. mansoni. snail-parasite compatibility was ...19938415568
comparison of hemocyte components from schistosoma mansoni (trematoda)-susceptible and resistant biomphalaria glabrata (gastropoda) that cross-react with larval schistosome surface proteins.1. cross-reactive antigens between larval schistosoma mansoni and hemocytes from schistosome-resistant and susceptible strains of biomphalaria glabrata were identified and compared using sodium dodecyl sulfate-polyacrylamide gel electrophoresis (sds-page), immunoblotting and surface radioiodination. 2. four sporocyst (larval s. mansoni) surface antigens (27, 39, 40 and 70 kda) reacted with antibodies to hemocytes from resistant snails whereas only one surface antigen (70 kda) was recognized by a ...19938472536
biochemical and morphological pathology of the foot of the schistosome vector biomphalaria glabrata infected with schistosoma mansoni.infection by schistosoma mansoni resulted in morphological and biochemical changes to the foot of its intermediate host, biomphalaria glabrata. migration through, and emergence of cercariae from, the foot was observed and evidenced by lesions on the ciliated foot surface. this was accompanied by a significant decrease in the velocity of movement by infected individuals. in vivo 31p nmr spectral analyses demonstrated that the foot of infected snails had a lower phosphoarginine (pa)/adenosine 5' t ...19938233591
transmission of schistosoma mansoni under experimental conditions using the bovine--biomphalaria glabrata-bovine model.three calves experimentally infected with schistosoma mansoni, and passing viable eggs in feces, as well as 5 normal calves (coming from a non-endemic area for schistosomiasis) kept as controls, were maintained in an enclosure (850 m2 in area). in this enclosure, a tank with water received 500 laboratory reared biomphalaria glabrata. all the control calves were infected for a period ranging from 79 to 202 days after the beginning of the experiment, and afterwards presented viable s. mansoni eggs ...19938278740
morphological characterization of the hemocytes of the pulmonate snail biomphalaria tenagophila.the blood cells of the pulmonate snail biomphalaria tenagophila, an important transmitter of the trematode schistosoma mansoni in brazil, were examined by light and transmission electron microscopy (tem). two hemocyte types were identified: hyalinocytes and granulocytes. hyalinocytes are small young (immature), poorly spreading cells, which have a high nucleocytoplasmic ratio and are especially rich in free ribosomes. they do not appear to contain lysosome-like bodies and represent less than 10% ...19938246758
production of heterogeneous carbohydrate-binding proteins by the host snail biomphalaria glabrata following exposure to echinostoma paraensei and schistosoma mansoni.hemolymph lectins may play an important role in the internal defense responses of gastropods to parasites. two groups of known carbohydrate-binding polypeptides, of 150-220 kda (designated as group 1 molecules, or g1m) and of 75-130 kda (group 2 molecules, or g2m), were harvested from pooled plasma samples of biomphalaria glabrata using affinity chromatography and examined using 2-dimensional electrophoresis. plasma samples were derived from control snails or snails exposed 8 days earlier to the ...19938501600
effects of schistosoma mansoni infection on phagocytosis and killing of proteus vulgaris in biomphalaria glabrata hemocytes.with the use of a fluorescence microassay, in vitro phagocytosis and killing of proteus vulgaris were measured in hemocytes of nih albino biomphalaria glabrata infected with schistosoma mansoni for 1, 2, 3, or 4 wk. although hemocytes of infected snails displayed decreased phagocytosis, relative to hemocytes of uninfected snails, at 4 wk postinfection (pi), they exhibited enhanced microbicidal activity at 3 wk pi. no microbicidal activity was detected in the plasma of either infected or uninfect ...19938459340
polypeptides synthesized in vitro by biomphalaria glabrata hemocytes bind to schistosoma mansoni primary sporocysts.in vitro labeled polypeptides secreted by schistosome-susceptible and -resistant biomphalaria glabrata were tested for their ability to bind the surface tegument of schistosoma mansoni primary (= mother) sporocysts. out of a complex pattern of sds-page-separated hemocyte polypeptides, only two (19 and 46 kda) bound to sporocysts. the 19-kda polypeptide consistently bound to both live and fixed sporocysts, although fixed larvae usually bound more than living sporocysts. the 46-kda component bound ...19938463708
invertebrate host-parasite relationships: convergent evolution of a tropomyosin epitope between schistosoma sp., fasciola hepatica, and certain pulmonate snails.monoclonal antibodies (mab) directed against schistosoma mansoni tropomyosin isoform, smtm (xu et al. experimental parasitology 69, 373-392, 1989), were used to test for cross-reactivity with biomphalaria glabrata antigens. one mab (1f10) recognized antigens of 39, 41, and 80 kda in a snail head/foot antigen preparation but not a hepatopancreas antigen preparation. another mab (1c1) cross-reacted with a 39-kda antigen in the head/foot extract but not in the hepatopancreas extract. epitope mappin ...19947512930
studies on host-parasite relationship between the puerto rican strain of schistosoma mansoni and biomphalaria snails.immunoelectrophoretic studies on common antigenicities were carried out by using rabbits sera immunized with the puerto rican strain of schistosoma mansoni adult worms or eggs and antigens of several adult biomphalaria snails and vice versa. as the result, s. mansoni adult worm extracts produced 8 bands both with extracts of biomphalaria glabrata pigmentation and b. glabrata pigmentado, 3 to 4 bands with those of b. glabrata albino and 1 to 2 bands with those of b. straminea. on the other hand, ...19947777917
schistosomicidal activities of lymnaea stagnalis haemocytes: the role of oxygen radicals.macrophage-like defence cells (haemocytes) of the pond snail lymnaea stagnalis mediate cytotoxicity through reactive oxygen intermediates (rois). this activity is nadph-oxidase dependent, as in mammalian phagocytes during the respiratory burst. in this study, mother sporocysts of schistosomes, the compatible trichobilharzia ocellata and the incompatible schistosoma mansoni evoke in vitro roi activities (detected by luminol dependent chemiluminescence, ldcl) from l. stagnalis haemocytes. s. manso ...19947800416
biomphalaria glabrata: extensive genetic variation in brazilian isolates revealed by random amplified polymorphic dna analysis.to examine the extent of genetic variation in biomphalaria glabrata, the intermediate host of schistosoma mansoni, specimens from seven brazilian isolates were studied. regions of genomic dna were amplified using short, arbitrarily selected oligonucleotide primers under low-stringency conditions (random amplified polymorphic dnas--rapds) and analyzed by polyacrylamide gel electrophoresis followed by silver staining. the rapd profiles of snails of the same isolate were relatively homogeneous, wit ...19947914497
interspecific stimulation of parthenogenesis in schistosoma intercalatum and s. mansoni.experimental studies of mating behaviour of schistosoma intercalatum and schistosoma mansoni in mixed infections in mice showed that in simultaneous infections, without the possibility of choice of mate, heterologous pairing occurs readily. the paired females reach sexual maturity, are inseminated and lay parthenogenetic eggs. miracidia originating from the s. mansoni male x s. intercalatum female are non infective to either biomphalaria glabrata or bulinus forskalii, whereas those from the reve ...19947930460
schistosoma mansoni: modulation of hemocyte surface polypeptides detected in individual snails, biomphalaria glabrata, following larval exposure.as an approach to better understand the molecular mechanisms underlying the differential cellular response to larval schistosoma mansoni observed in biomphalaria glabrata, we have analyzed hemocyte membrane-associated polypeptides from inbred susceptible and resistant strains of b. glabrata. a combination of techniques involving biotin-labeling of cell surface-exposed polypeptides and a highly sensitive chemiluminescent detection technique has allowed the identification of major polypeptides exp ...19948050520
schistosoma mansoni: relationship between low fecundity and reduced susceptibility to parasite infection in the snail biomphalaria glabrata.biomphalaria glabrata snails which were not susceptible as juveniles to infection by schistosoma mansoni were selectively bred (by self-fertilization) from the highly susceptible nmri laboratory snail stock. the susceptibility rate among juvenile snails derived from interbreeding nmri parents was initially 85-95%, but after several generations of selection, less than 5% of exposed snails became infected by the parasite. selection for low susceptibility also resulted in a large proportion of snai ...19948050522
high performance thin-layer chromatographic analysis of sugars in biomphalaria glabrata (gastropoda) infected with echinostoma caproni (trematoda).high performance thin-layer chromatographic analysis was done on the hemolymph and digestive gland-gonad complex (dgg) of biomphalaria glabrata snails experimentally infected with the intramolluscan stages of echinostoma caproni. the major sugars detected in both the dgg and hemolymph of infected and uninfected snails were glucose and trehalose. quantitative analysis by scanning densitometry showed a significant reduction in glucose in both the hemolymph and dgg of infected snails at 4, 6, and 8 ...19948158483
transfer of resistance to schistosoma mansoni in biomphalaria glabrata by allografts of amoebocyte-producing organ.allografts of amoebocyte-producing organ (apo) were implanted heterotopically into the schistosome-susceptible nih albino stock of biomphalaria glabrata from either 13-16-r1 (a schistosome-resistant stock) or nih albino donors. at 3, 7-8, 14-15, 21, 28-33, or 47-71 days postimplantation (pi), allograft recipients were exposed to 50 miracidia each of schistosoma mansoni and subsequently monitored for development of sporocysts and cercariae. relative to untampered snails and recipients of nih albi ...19948195947
interleukin 1 activity in haemolymph from strains of the snail biomphalaria glabrata varying in susceptibility to the human blood fluke, schistosoma mansoni: presence, differential expression, and biological function.cytokines control many of the steps in the complex pathways of immune and inflammatory responses in mammals. recent reports also indicate that some invertebrates may produce cytokines such as interleukin 1 (il-1). certain strains of the snail, biomphalaria glabrata (intermediate host for the human blood fluke, schistosoma mansoni), possess a soluble plasma factor that stimulates the haemocyte-mediated killing of larval schistosomes, making them resistant to infection. in this study, we have soug ...19948003629
parthenogenesis in the genus schistosoma: electrophoretic evidence for this reproduction system in s. japonicum and s. mansoni.mixed infections with schistosoma japonicum and s. mansoni were carried out in mice. s. japonicum females paired with s. mansoni males developed normally and produced numerous viable eggs; very little sperm was found in the female genital tract. the eggs yielded many miracidia infective to oncomelania hupensis, the host of s. japonicum. cercariae arising from miracidia developed into male worms with an electrophoretic pattern of malate dehydrogenase (mdh) corresponding only to the maternal speci ...19948036230
[susceptibility of biomphalaria tenagophila and biomphalaria glabrata from a same region to 2 schistosoma mansoni strains].b. tenagophila snails from ouro branco, mg, showed positivity for s. mansoni, with infection rates of 5%, 10%, (sj strain), and 1% (le strain) using a pool of miracidia. the mollusks were found to be susceptive from the 3rd generation reared in laboratory onwards. the b. tenagophila (ob, mg) when individually exposed to 10 miracidia, showed infection rate of 2% for le strain. b. glabrata snails from gagé, mg, showed a positivity rate of 58% for s. mansoni (le strain), under experimental conditio ...19947569607
characterization of immunoreactive tnf alpha molecules in the gastropod biomphalaria glabrata.in recent years, several studies have demonstrated the existence of cytokine-like molecules in invertebrates, therefore suggesting that cytokines may have been conserved throughout evolution. in this study, we investigated the presence of immunoreactive tnf alpha (ir tnf alpha) in the gastropod mollusc biomphalaria glabrata, the specific intermediate host for the trematode schistosoma mansoni. immunocytochemical study indicated the presence of ir tnf alpha in mollusc hemocytes corresponding to a ...19948001700
surface membrane polypeptides associated with hemocytes from schistosoma mansoni-susceptible and -resistant strains of biomphalaria glabrata (gastropoda).previous studies have shown that hemocytes from inbred susceptible and resistant strains of the snail, biomphalaria glabrata, differentially react to primary sporocysts of the blood fluke, schistosoma mansoni. it has been hypothesized that this differential reactivity may be due to differences in the expression of hemocyte surface determinants serving as parasite recognition and/or hemocyte activating factors. in order to begin addressing this hypothesis the hemodynamics and surface polypeptides ...19948106743
production of schistosoma mansoni cercariae by biomphalaria glabrata from a focus in belo horizonte, minas gerais.the snail density, levels of infection and the monthly production of schistosoma mansoni cercariae by biomphalaria glabrata were determined in a focus of barreiro de baixo (belo horizonte, mg, brazil). during a period of 38 months (1984 to 1987) 5,366 snails were collected of which 324 (6.03%) were infected with s. mansoni. the total number of cercariae shed was 5,667,312. each snail shed an average of 17,422 cercariae during the time that it was under study in the laboratory. the greatest longe ...19947569620
schistosoma mansoni: interleukin-1 increases phagocytosis and superoxide production by hemocytes and decreases output of cercariae in schistosome-susceptible biomphalaria glabrata.decreases in the number of schistosoma mansoni cercariae released from susceptible m-line biomphalaria glabrata were detected following injection with the recombinant human cytokine, interleukin-1. no differences in either the time post-exposure at which shedding began or the percentage of snails shedding cercariae were detected between interleukin-1 injected, heat-inactivated interleukin-1 injected, or sham injected controls. however, sham injected and heat-inactivated interleukin-1 injected sn ...19957821403
spatial distribution patterns of the sporocyst infrapopulation of schistosoma mansoni within its mollusc host (biomphalaria glabrata): an unusual phenotype of aggregation.a study carried out on the intramolluscan development of the larval stages of schistosoma mansoni from venezuela in its intermediate host biomphalaria glabrata shows the existence of 2 patterns for the spatial distribution of daughter sporocysts within the digestive gland of the snail. besides the normal pattern, which is a random distribution of daughter sporocysts within the gland, 11% of the infected snails harbored an infection phenotype with daughter sporocysts strongly aggregated in only t ...19957707215
distribution of schistosome genetic diversity within molluscan intermediate hosts.naturally infected biomphalaria glabrata snails were collected at two sites near belo horizonte, brazil, and schistosoma mansoni cercariae isolated from single snails were used to infect individual mice. genetic comparison of single worm dna was accomplished by hybridization of southern blots to a polymorphic repetitive dna element. genetic profiles of parasite individuals revealed a diverse array of parasite genotypes in naturally infected intermediate hosts. the observed distribution of schist ...19957675537
schistosoma mansoni: excretory-secretory polypeptides exhibit selective binding to plasma components of the snail biomphalaria glabrata.previous studies have shown that schistosoma mansoni excretory-secretory polypeptides (esp) inhibit various internal defense functions of hemocytes from biomphalaria glabrata and that plasma also may exert a modulatory effect on hemocyte activity. to better understand how plasma may influence hemocyte-schistosome interactions in inbred strains of snails, biotinylated esp (b-esp) were used as probes to identify esp-reactive plasma components and partially characterize the nature of their binding ...19957498426
development of schistosoma mansoni in biomphalaria tenagophila, biomphalaria straminea and biomphalaria glabrata.a comparative study of the development of schistosoma mansoni during the intra-molluscan phase was made by means of histological sections of biomphalaria tenagophila, b. straminea and b. glabrata from brazil. two hundred snails of each species were individually exposed to 50 miracidia of the s. mansoni, al line. no larvae were observed in the snails fixed 72 h after exposure. in specimens shedding cercariae, 31 days after exposure tissue reactions encapsulating the larvae were seen in b. tenagop ...19958525264
hemocytes of schistosome-resistant and -susceptible biomphalaria glabrata recognize different antigens on the surface of schistosoma mansoni sporocysts.a cytoadherence assay was used to determine whether antibodies to plasma and hemocyte components of schistosoma mansoni-susceptible (m-line) and -resistant (10-r2, 13-16-r1) strains of biomphalaria glabrata affected attachment of hemocytes to chemically fixed schistosome sporocysts differentially. experiments used purified, intact igg and purified fab fragments of each antibody. indirect fluorescent antibody tests confirmed that the intact purified igg to plasma and hemocytes from the 3 strains ...19957707192
production of schistosoma mansoni daughter sporocysts from mother sporocysts maintained in synxenic culture with biomphalaria glabrata embryonic (bge) cells.in vitro production of schistosoma mansoni daughter sporocysts (ds) from miracidium-derived mother sporocysts (ms) was achieved by synxenic larval cultivation with cells of the biomphalaria glabrata embryonic (bge) cell line. the in vitro growth and viability of ms cocultured with bge cells or in bge cell-conditioned medium were significantly extended beyond that of larvae cultured in fresh medium alone. however, complete ds development and emergence from ms were achieved only in the presence of ...19957472861
killing of schistosoma mansoni sporocysts in biomphalaria glabrata implanted with amoebocyte-producing organ allografts from resistant snails.schistosome-susceptible national institutes of health (nih) albino biomphalaria glabrata were implanted with the amoebocyte-producing organ (apo) from 4 types of donors: (1) exposed-resistant (er), i.e., schistosome-resistant 13-16-r1 snails that had been exposed to miracidia of schistosoma mansoni 30 or more days previously in order to verify their resistance, (2) exposed-susceptible (es), i.e., nih albino snails that had been similarly exposed to miracidia, (3) unexposed-resistant (ur), and (4 ...19957472893
[relationship between the pathogenicity of schistosoma mansoni in mice and the susceptibility of the vector mollusk. iii. mortality, body and viscera weight].the relationship between the development of hepatomegaly, splenomegaly, body weight and mortality rate and the degree of susceptibility of biomphalaria glabrata and b. tenagophila at which infective cercariae developed was studied. the study utilized swiss mice, spf, as definitive hosts and populations of snails genetically selected for character susceptibility as intermediate hosts. low body weight and smaller viscera were observed in infected mice with cercariae originating from snails that sh ...19958729275
dna polymorphism of schistosomes and their snail hosts.analysis of the genomes of schistosomes and one of their intermediate hosts, biomphalaria glabrata, using random amplified polymorphic dna (rapd) demonstrated that intraspecific genetic polymorphism in the parasite is limited but in the snail is highly pronounced. this suggests an important role for the snail in the determination of the epidemiology of the disease. in addition to their intraspecific stability, schistosome derived rapds exhibit a high level of interspecific polymorphism and are t ...19958531659
a method for immunoisolation of sporocysts of schistosoma mansoni in nonsusceptible snails.a technique is described for immunoisolation of sporocysts of schistosoma mansoni in nonsusceptible biomphalaria glabrata by microencapsulation in agarose. based on histological evidence, all 11 microencapsulated sporocysts implanted into 3 schistosome-resistant 13-16-r1 snails were alive at 72 hr postimplantation, although in a developmentally retarded condition. however, among 146 sporocysts derived from miracidia that had penetrated 5 snails, 96% were dead by 72 hr. these results suggest that ...19958544049
schistosoma mansoni: changes in the albumen gland of biomphalaria glabrata snails selected for nonsusceptibility to the parasite.the lac-line strain of the snail biomphalaria glabrata has very low susceptibility to the parasite schistosoma mansoni and a very low reproductive potential. upon examination of the reproductive tract of these snails, light and electron microscopy revealed obvious abnormalities in the albumen gland. secretory cells that are normally cuboidal in susceptible nmri (f0) snails were squamous in lac-line snails. these lac-line cells contained small secretory granules and negligible rough endoplasmic r ...19958544062
longitudinal study of circadian rhythms in the cercarial emergence of schistosoma mansoni from biomphalaria glabrata. 19958551950
cercarial emergence of schistosoma mansoni from biomphalaria glabrata and biomphalaria straminea. 19958569474
influence of temperature on development of schistosoma mansoni female cercariae in biomphalaria glabrata.in these experiments the ratio of male to female s. mansoni larvae in b. glabrata from belo horizonte and ribeirão das neves minas gerais, brazil, either reared in laboratory or collected in the field, varied from 1:1 to 1:1.3 or 1.4:1. cercariae of le strain of schistosoma mansoni, shed by 39 snails maintained at 25 +/- 0.5 degrees c were used to infect mice on a weekly basis. subsequent perfusion resulted in 76.6% male and 23.4% female worms. the cercariae produced by 32 infected snails mainta ...19958599060
the plasma proteins of biomphalaria glabrata in the presence and absence of schistosoma mansoni.snail plasma serves as both a sink for metabolites and a source of nutrients for parasites developing within their intermediate hosts. it also contains molecules involved in immunological events like non-self recognition, phagocytosis and encapsulation. in this study we present improved protocols for the separation and partial characterization of plasma proteins of schistosome-susceptible and resistant strains of biomphalaria glabrata. within each strain, the plasma of snails 12, 24, 48 and 72 h ...19958595817
altered nutrition and assimilation of the snail host (biomphalaria glabrata) as a consequence of the parasitic spatial constraint (schistosoma mansoni). 19969133164
[behavior of hemolymph amebocytes from planorbidae in the presence of schistosoma mansoni larvae parasitism, after inoculation of indian ink or fracture of the shell].the behavior of the hemolymph amebocytes of biomphalaria glabrata and biomphalaria tenagophila was studied by means of the infection by the schistosoma mansoni, using inoculation with indian ink and fracture of the shell. a differential count of the amebocytes in the hemolymph was made with special attention given to the types of cell found in each sample. histopathological evaluation of the molluscs exposed to the schistosoma mansoni miracidia and analyses of the amebocytes were made. correlati ...19969201894
a low stringency polymerase chain reaction approach to the identification of biomphalaria glabrata and b. tenagophila, intermediate snail hosts of schistosoma mansoni in brazil.the low stringency-polymerase chain reaction (ls-pcr) with a pair of specific primers for the amplification of the 18s rrna gene was evaluated as a means of differentiating between the two schistosoma mansoni intermediate host species in brazil: biomphalaria glabrata and b. tenagophila. individual snails obtained from different states of brazil were used and the amplification patterns obtained showed a high degree of genetic variability in these species. nevertheless, 4 and 3 clearly defined spe ...19969283656
urban schistosomiasis: morbidity, sociodemographic characteristics and water contact patterns predictive of infection.schistosomiasis (schistosoma mansoni) is classically described as a rural disease that occurs in areas with poor sanitary conditions. this cross-sectional study was undertaken in a suburban area of a large industrialized city in brazil (belo horizonte), aiming at examining epidemiological characteristics of schistosomiasis in an urban setting.19969027538
schistosoma mansoni: the sex ratios of worms in animals infected with cercariae from three species of biomphalaria.the ratios of male to female worms of schistosoma mansoni were determined in mice infected with cercariae from le, sj and al strains shed by mollusc hosts of the parasite in brazil. the sex ratios of worms in the animals were similar with cercariae from biomphalaria glabrata and b. tenagophila varying from 1.1:1 to 1.6:1 with le and al strains and 1:1.1 with sj. in the animals infected with cercariae from b. straminea the ratio of male to female worms was similar to those obtained using cercaria ...19969071034
use of rapd-pcr to differentiate genetically defined lines of an intermediate host of schistosoma mansoni, biomphalaria glabrata.the genetic differentiation among several laboratory-maintained pedigree snail lines of biomphalaria glabrata (with different susceptibility phenotypes to schistosoma mansoni infection) was assessed with the random amplified polymorphic dna method. out of the 20 primers tested, 2 (opa-01 and opa-06) gave reproducible markers with either individual or bulked dna samples from resistant (bs-90, 10-r2, lac-line) and susceptible (m-line) snails. arbitrary primer, opa-01, amplification of bs-90 dna id ...19968604090
killing of schistosoma mansoni sporocysts by biomphalaria glabrata hemolymph in vitro: alteration of hemocyte behavior after poly-l-lysine treatment of plastic, and the kinetics of killing by different host strains.behavior of hemocytes of the gastropod mollusc biomphalaria glabrata was markedly changed on plastic by treatment of the substrate with 0.1 mg/ml poly-l-lysine compared to behavior on untreated plastic. on lysine, the cells showed minimal spreading, moved significantly faster, and formed aggregates. cell-mediated cytotoxicity (cmc) assays were set up on the modified and untreated substrates to compare the killing capacities of b. glabrata hemocytes against schistosoma mansoni sporocysts. hemolym ...19968604109
male reproductive success of schistosoma mansoni-infected biomphalaria glabrata snails.infection of biomphalaria glabrata by schistosoma mansoni results in a dramatic reduction in the snail's ability to produce eggs. we studied the ability of such parasitically castrated snails to fertilize the eggs of uninfected snails. pigmented b. glabrata snails (13141 stock) were infected with s. mansoni miracidia and reared individually until they ceased laying eggs. these infected snails were then given the opportunity to mate with uninfected albino (nmri) snails. each of the infected snail ...19968636847
analysis of lectin- and snail plasma-binding glycopeptides associated with the tegumental surface of the primary sporocysts of schistosoma mansoni.carbohydrates associated with the tegumental surface of schistosoma mansoni primary sporocyst may serve as potential receptors for mediating recognition by the internal defence system of the molluscan host, biomphalaria glabrata. therefore, a combination of sds-page and lectin probe analyses were carried out on biotin-labelled tegumental glycopeptides as a first step to defining the carbohydrates expressed at the sporocyst surface. the majority of surface polypeptides, ranging in relative molecu ...19968677136
biogenic monoamines in the freshwater snail, biomphalaria glabrata: influence of infection by the human blood fluke, schistosoma mansoni.the biogenic monoamines, serotonin (5-ht), dopamine (da) and l-dopa were measured using high performance liquid chromatography with electrochemical detection (hplc-ed) in the extracts of the central nervous system (cns) and plasma of uninfected freshwater snails, biomphalaria glabrata, and in snails at 7, 14, 21 and 28 days postexposure (pe) to the miracidia of the human blood fluke, schistosoma mansoni. relative to age-matched uninfected snails, a general depression of biogenic amine levels was ...19968759145
circadian pattern of cercarial emergence in schistosoma mansoni (platyhelminthes:digenea) from isolated biomphalaria glabrata.the present work aimed to compare the acrophases (peak hours) of emergence of schistosoma mansoni cercariae among isolated individuals of the snail biomphalaria glabrata. laboratory stocks of melanic b. glabrata from the same biotope as the s. mansoni strain (belo horizonte, minas gerais) were used. twenty-two snails individually exposed to five miracidia were tested. chronobiological trials were performed outdoors after an acclimation period of at least a week. three groups of snails were teste ...19968877118
identification of the first major allergen of a squid (todarodes pacificus).in japan, squid is an important seafood, and some patients with food allergies are sensitive to squid. there has been no report, however, describing the major allergens of squid.19968939158
schistosoma mansoni: the ultrastructure of larval morphogenesis in biomphalaria glabrata and of associated host-parasite interactions.an electron microscopic study has been carried out to describe the transformation of the miracidium of s. mansoni into the mother sporocysts in the susceptible b. glabrata and the associated host-parasite interactions. the miracidium enters the snail host without morphological alterations. within 3 hr after entering, all the ciliary epidermal plates of the miracidium are discarded. a new tegument is quickly formed by 5 hr postinfection by the expansion of epidermal ridges. the rapid formation of ...19969086392
schistosoma mansoni: use of a subtractive cloning strategy to search for rflps in parasite-resistant biomphalaria glabrata.a subtractive cloning strategy has been applied for the identification of two cdna clones whose corresponding transcripts were elevated in schistosoma mansoni-resistant (bs-90) compared to susceptible (m-line) snails. clone pbs11 encoded a 1.9-kb transcript that was more elevated compared to a 500-bp transcript encoded by clone pbs12. consequently, more attention was focused on the molecular characterization of clone pbs11. results showed that the transcript encoded by this clone was expressed i ...19968948331
phagocytosis of latex beads by biomphalaria glabrata hemocytes is modulated in a strain-specific manner by adsorbed plasma components.circulating phagocytes of the mollusc biomphalaria glabrata help determine the fate of invading schistosoma mansoni larvae. in mediating cytotoxicity against this trematode parasite, phagocytic hemocytes may interact with unidentified plasma components. in this study, positively and negatively charged latex beads were coated with plasma for use in in vitro phagocytosis assays. hemocytes from s. mansoni-susceptible and -resistant strains of b. glabrata were tested for their ability to internalize ...19968738934
biomphalaria glabrata: a new threat for schistosomiasis transmission in egypt.this is the first report on the infestation of irrigation and drainage systems at giza, qalyoubiya and kafr el shiekh governorates, with biomphalaria glabrata (the snail host of schistosoma mansoni in the new world). identification of this snail species was based on morphometry of the shell, shape of the radular lateral teeth and presence of the characteristic renal ridge. b. glabrata snails collected from natural water courses in egypt proved to be susceptible to a local strain of s. mansoni. t ...19968721240
inhibition of cysteine proteinase from schistosoma mansoni larvae by alpha-macroglobulin from the plasma of biomphalaria glabrata.the hemolymph of biomphalaria glabrata, a molluscan host of schistosoma mansoni, contains an alpha-macroglobulin proteinase inhibitor (alpham). in this study we have demonstrated that this host molecule inhibits a cysteine proteinase produced by larval s. mansoni. inhibition by alpham involves conformational changes through proteolytic cleavage by the proteinase, thus the enzyme must be active for interactions to occur. a specific cysteine proteinase inhibitor (e64) was used to block the interac ...19968604113
schistosoma mansoni: distribution patterns of miracidia among biomphalaria glabrata snail as related to host susceptibility and sporocyst regulatory processes.parasite prevalences, miracidia developmental capacity, mother sporocyst mean intensities, sporocyst distribution patterns, and cercarial production levels were determined after individual exposure of biomphalaria glabrata snails to increased doses of schistosoma mansoni miracidia for two geographical strains (brazilian, bre, and guadeloupean, gua) of host and parasite. for a high level (100%) of host-parasite susceptibility and in the absence of mother sporocyst regulatory processes for the bre ...19979024196
change in schistosome sex ratio under the influence of a biotic environmental-related factor.schistosoma mansoni is a dioecious trematode responsible for intestinal schistosomiasis in man. the sex ratio was determined for s. mansoni adults derived from cercariae obtained from infected biomphalaria glabrata maintained in the presence of the nonvector molluse. marisa cornuarietis. the presence of m. cornuarietis is responsible for enhanced growth of b. glabrata and for a change in the sex ratio of the schistosome, which becomes more male-biased as compared to control snails maintained in ...19979105300
a family of fibrinogen-related proteins that precipitates parasite-derived molecules is produced by an invertebrate after infection.after infection with the digenetic trematode echinostoma paraensei, hemolymph of the snail biomphalaria glabrata contains lectins comprised of 65-kda subunits that precipitate polypeptides secreted by e. paraensei intramolluscan larvae. comparable activity is lacking in hemolymph of uninfected snails. three different cdnas with sequence similarities to peptides derived from the 65-kda lectins were obtained and unexpectedly found to encode fibrinogen-related proteins (freps). these freps also con ...19979238039
[the resistance of biomphalaria glabrata to schistosoma mansoni infection: variations in the prepatent period and in compatibility].biomphalaria glabrata from belo horizonte, minas gerais, brazil, reared in laboratory, has a level of infection of 90% when exposed to 20 miracidia of the autochibonous le strain. the prepatent period was of 5 to 7 weeks whereas 5 to 10% of exposed snails do not shed cercariae. the eggs of negative snails were collected and the progeny was again submitted to individual infection with 20 miracidia. the mean of infection from f14 to f20 was of 43.6%. histological sections from f12, f14 and f15 sna ...19979265222
partially degraded dna of parasitological interest serves as an adequate template for the production of random amplified polymorphic dnas (rapds).genomic dna was extracted from schistosoma mansoni adult worms and deliberately degraded by sonication. samples with varying average molecular weight were subjected to rapd (randomly amplified polymorphic dna) analysis using the primer 3307 (5'-agtgctacgt-3') and other primers. reproducible and complex dna banding patterns were obtained, irrespective of the extent of dna degradation. the same amplification protocol was employed with naturally degraded biomphalaria glabrata genomic dna and the pr ...19979267422
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