Publications
| Title | Abstract | Year(sorted ascending) Filter | PMID Filter |
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| 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 ... | 2002 | 12109739 |
| 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 ... | 2002 | 12117501 |
| 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 ... | 2002 | 12219145 |
| 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 ... | 2002 | 12242641 |
| 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 ... | 2002 | 12242642 |
| 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 ... | 2002 | 12386715 |
| 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 ... | 2002 | 12426585 |
| 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 ... | 2002 | 12426594 |
| 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. ... | 2002 | 12426595 |
| 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 ... | 2002 | 12426602 |
| 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 ... | 2003 | 12489007 |
| 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 ... | 2003 | 12489010 |
| comparative gene analysis of biomphalaria glabrata hemocytes pre- and post-exposure to miracidia of schistosoma mansoni. | the internal defense mechanism of the snail biomphalaria glabrata during a schistosome infection is activated and mediated via the immune effector cells known as hemocytes. since resistance and susceptibility to schistosome infection is known to be genetically determined, our interest was to use the est approach as a gene discovery tool to examine transcription profiles in hemocytes of resistant snails pre- and post-exposure to schistosoma mansoni. comparative analysis of the transcripts suggest ... | 2003 | 12615317 |
| effects of plagiorchis elegans (digenea: plagiorchiidae) infection of biomphalaria glabrata (pulmonata: planorbidae) on a challenge infection with schistosoma mansoni (digenea: schistosomatidae). | prior exposure of biomphalaria glabrata to the eggs of an incompatible digenean, plagiorchis elegans, rendered this snail host less suitable to a compatible species, schistosoma mansoni. although p. elegans failed to develop patent infections in b. glabrata, it reduced the production of s. mansoni cercariae by 88%. concomitantly, host attributes such as reproduction, growth, and survival were compromised. the effect of p. elegans infection was most severe among snails that, in addition, had deve ... | 2003 | 12659305 |
| extra-cellular matrix changes in schistosoma mansoni-infected biomphalaria glabrata. | reactivity of snails against parasites exhibits a primitive focal reaction, with encapsulation, phagocytosis and destruction of parasite larvae by macrophage-like cells - the hemocytes. this reaction mimics granulomatous inflammation seen in higher animals. however, different from the latter, little is known about the participation of extra-cellular matrix in such snail defense reactions. normal and schistosoma mansoni-infected biomphalaria glabrata of different strains were submitted to cytolog ... | 2003 | 12700871 |
| [schistosomiasis in hyperendemic area of taquarendi: i- schistosoma mansoni infection and severe clinical forms]. | the study was carried out in taquarendi (bahia), a caatinga zone with a small irrigated strip of land, where biomphalaria glabrata snails are found. from the 1,532 inhabitants, 1,105 (72.1%) were submitted to clinical examination and 1058 out of them (95.7%) made stool examinations. prevalence of schistosomiasis was 73.1% and 16.2% of these patients eliminated more than 1,000 eggs per gram of stool. by clinical examination, the size and the consistency of the left liver lobe were increased in 54 ... | 2003 | 12806456 |
| pharmacological and autoradiographical characterization of serotonin transporter-like activity in sporocysts of the human blood fluke, schistosoma mansoni. | the present study focuses on the role of the biogenic monoamine serotonin (5-hydroxytryptamine) in the biology of sporocyst stages of the human blood fluke, schistosoma mansoni, and its importance during obligate development within its snail host biomphalaria glabrata. based on previous work demonstrating that snails infected with s. mansoni have reduced levels of 5-hydroxytryptamine, we hypothesized that sporocysts actively transport this molecule from the host milieu. intact sporocysts isolate ... | 2003 | 12861423 |
| altered behavior of the snail biomphalaria glabrata as a result of infection with schistosoma mansoni. | in this comparative behavioral study, the effect of infection with schistosoma mansoni on its snail intermediate host biomphalaria glabrata was investigated. three groups of snails were compared for their activity: (1) uninfected, (2) infected with male parasites, and (3) infected with female parasites. in solitary movement trials, uninfected snails traveled greater distances at faster rates, explored more surface area, and had shorter rest periods than snails infected with either male or female ... | 2003 | 12880237 |
| the respiratory properties of biomphalaria glabrata exposed to schistosoma mansoni infection, starvation, co, and choices of different oxygen concentrations. | the oxygen consumption rate (vo(2)) of biomphalaria glabrata populations, using polarometric and manometric methods, when plotted against dried body mass as logarithmic co-ordinates, respectively, fell on a regression line with a slope between 0.933 and 1.02. the slope of the regression line for non-infected schistosoma mansoni populations was found to be 1.04 with no differences in the vo(2) between infected and non-infected snails. the vo(2) of co-treated snails was the same as for the control ... | 2003 | 12880585 |
| apparent competition through facilitation between melanoides tuberculata and biomphalaria glabrata and the control of schistosomiasis. | interactions between two species that result in reduced growth rates for both and extinction of one of the species are generally considered cases of asymmetric interspecific competition. exploitative or interference competition is the usual mechanism invoked. here we describe another mechanism producing the same result, named apparent competition through facilitation (acf), observed between melanoides tuberculata and biomphalaria glabrata populations. the superior competitor actually gives some ... | 2003 | 12886429 |
| parasite infection, host resistance and mate choice: battle of the genders in a simultaneous hermaphrodite. | parasites have been proposed to be fundamental in the evolution of mate choice because differential mating on the basis of heritable disease resistance is expected to lead to progeny with a better genome-environment match than random mating. however, direct empirical data in support of this hypothesis are often lacking, and the relative influences of current and potential infection status (i.e. resistance genotype), and of mate choice versus mate conflict, remain largely unknown. we demonstrate ... | 2003 | 12965013 |
| transplantation of in vitro-generated schistosoma mansoni mother sporocysts into biomphalaria glabrata. | specific studies on schistosome gene functions require both access to the parasite stages, preferably the larvae, and to complete the life cycle. in the present study, we investigated whether short-term in vitro cultivation of sporocysts and surgical transplantation into snails could be combined to produce cercariae. miracidia were maintained in vitro in the presence of biomphalaria glabrata embryonic (bge) cells or, alternatively, in bge-cell-conditioned medium. the transformation of miracidia ... | 2003 | 14551763 |
| acute schistosomiasis outbreak in the metropolitan area of belo horizonte, minas gerais: alert about the risk of unnoticed transmission increased by growing rural tourism. | the present article describes the occurrence of 17 cases of acute schistosomiasis in the metropolitan area of belo horizonte, state of minas gerais, brazil. all individuals affected took a bath in a swimming pool of a holiday resort that was provided with water from a nearby brook. the apparently clean water and the absence of snails in the pool gave the wrong impression that there was no risk for infection. during a malacological survey at the site snails of the species biomphalaria glabrata we ... | 2003 | 14595449 |
| a comparative parasitologic study on biomphalaria glabrata snail and c3h/he mice infected with human and murine isolates of schistosoma mansoni derived from sumidouro, rio de janeiro, brazil. | experiments were carried out to analyze the biological characteristics of two sympatric isolates of schistosoma mansoni derived from humans and murines in a low endemic transmission area (sumidouro county, state of rio de janeiro, brazil). sympatric reared-laboratory biomphalaria glabrata and c3h/he mice were used as experimental hosts. parameters assessed comprised: precercarial period, infectivity and mortality (snails), prepatent period, infectivity (percentage of cercariae maturation into ad ... | 2003 | 14595456 |
| genome size estimates for two important freshwater molluscs, the zebra mussel (dreissena polymorpha) and the schistosomiasis vector snail (biomphalaria glabrata). | the haploid genome sizes of two important molluscs were assessed by feulgen image analysis densitometry. the genome size of the zebra mussel (dreissena polymorpha), a prolific invader of north american lakes, was estimated to be 1c = 1.70 +/- 0.03 pg, and that of the freshwater snail biomphalaria glabrata, the predominant intermediate vector of the human parasite schistosoma mansoni, was estimated at 0.95 +/- 0.01 pg. these estimates will be important in future efforts in molluscan genomics, whi ... | 2003 | 14608401 |
| phylogeography of biomphalaria glabrata and b. pfeifferi, important intermediate hosts of schistosoma mansoni in the new and old world tropics. | the historical phylogeography of the two most important intermediate host species of the human blood fluke schistosoma mansoni, b. glabrata in the new world, and b. pfeifferi in the old world, was investigated using partial 16s and nd1 sequences from the mitochondrial genome. nuclear sequences of an actin intron and internal transcribed spacer (its)-1 were also obtained, but they were uninformative for the relationships among populations. phylogenetic analyses based on mtdna revealed six well-di ... | 2003 | 14629384 |
| schistosoma mansoni and echinostoma caproni excretory-secretory products differentially affect gene expression in biomphalaria glabrata embryonic cells. | biomphalaria glabrata embryonic (bge) cells have been shown to be a valuable in vitro cellular model for the study of snail host-parasite interactions. they both promote the growth and differentiation of various trematode species including schistosoma mansoni, and echinostoma caproni and share some morphological and functional features with circulating haemocytes. as an approach to investigate snail genes potentially regulated following exposure to trematode excretory-secretory (es) products, we ... | 2003 | 14700189 |
| difference in the susceptibility to certain molluscicides and schistosoma mansoni infection of three forms egyptian biomphalaria glabrata. | the first generation of 3 morphologically different forms of b. glabrata collected from giza were compared for lc50 values susceptibility to bayluscide and copper sulphate (chemical molluscicides) and anagallis arvensis and calendula micrantha (plant molluscicides) and to schistosoma mansoni infection. form (2) as juvenile and adult were less sensitive to c. micrantha and a. arvensis. form (3) as juvenile and form (1) as adult were least sensitive to cuso4. approximately the same susceptibility ... | 2003 | 14708851 |
| miracidia of an egyptian strain of schistosoma mansoni differentiate between sympatric snail species. | the host-finding behavior of miracidia of 2 strains of schistosoma mansoni from egypt and brazil was studied by recording their responses to snail-conditioned water (scw) from the egyptian sympatric snails, biomphalaria alexandrina, physa acuta, lymnaea cailliudi, and balinus truncatus, as well as from biomphalaria arabica and biomphalaria glabrata. miracidia of the egyptian strain significantly preferred scw from their compatible hosts b. alexandrina and b. arabica and showed no or a weak respo ... | 2003 | 14740921 |
| schistosoma mansoni miracidia transformed by particle bombardment infect biomphalaria glabrata snails and develop into transgenic sporocysts. | miracidia (and adults) of schistosoma mansoni which had been subjected to particle bombardment with a plasmid dna encoding enhanced green fluorescent protein (egfp) under control of the s. mansoni heat shock protein 70 (hsp70) promoter and termination elements were shown to express the reporter gene. bombarded miracidia were able to penetrate and establish in biomphalaria glabrata the intermediate host snail. gold particles could be detected in the germ balls of parasites in paraffin-sections of ... | 2003 | 14969695 |
| synthesis and evaluation of the molluscicidal activity of the 5,6-dimethyl-dihydro-pyran-2,4-dione and 6-substituted analogous. | five dihydro-piran-2,4-diones, including 5,6-dimethyl-dihydro-piran-2,4-dione one of the intermediates of the synthesis of caloverticilic acid, were synthesized and submitted to molluscicidal bioassay. the compound's yields varied from moderate to good (42%- 80%) and were achieved through the preparation of the dianion of ethyl acetoacetate, reaction with and aldehyde followed by hydrolysis of the ester (naoh, h(2)o, 2 h, t.a.) and lactonization in acidic medium (hcl, 0 degrees c). the 5,6-dimet ... | 2004 | 14980598 |
| mitotic responses to extracts of miracidia and cercariae of schistosoma mansoni in the amebocyte-producing organ of the snail intermediate host biomphalaria glabrata. | suspensions of miracidia and cercariae of schistosoma mansoni were subjected to repeated freeze-thaw cycles and then injected into resistant salvador strain biomphalaria glabrata snails. a pronounced increase in the number of mitotic figures, relative to uninjected, sham-injected, or diluent (water)-injected controls, was observed in the amebocyte-producing organ (apo) at 3 days postinjection (pi). after centrifugation of miracidia freeze-thaw extract (fte), the resulting supernatant (fts) and p ... | 2004 | 15040672 |
| heredity of specific host-finding behaviour in schistosoma mansoni miracidia. | two strains of schistosoma mansoni were used to investigate the hereditary basis of species-specific host recognition by analysing behavioural responses of miracidia to snail-conditioned water. an egyptian strain of s. mansoni, capable of distinguishing its host snail biomphalaria alexandrina from other snails was cycled repeatedly through biomphalaria glabrata, the intermediate host of a brazilian strain known to respond even to non-susceptible snails with high intensity. after 5 cycles in the ... | 2004 | 15206466 |
| schistosoma mansoni: resistant specific infection-induced gene expression in biomphalaria glabrata identified by fluorescent-based differential display. | the freshwater tropical snail biomphalaria glabrata is an intermediate host for schistosoma mansoni, the causative agent of human intestinal schistosomiasis, and strains differ in their susceptibility to parasite infection. changes in gene expression in response to parasite infection have been simultaneously examined in a susceptible strain (nhm1742) and a resistant strain (nhm1981) using a newly developed fluorescent-based differential display method. such rna profiling techniques allow the exa ... | 2004 | 15208043 |
| freshwater snails and schistosomiasis mansoni in the state of rio de janeiro, brazil: iv - sul fluminense mesoregion. | in this paper, the forth of a series dealing with the survey of freshwater gastropods of the state of rio de janeiro, the results of collections carried out in the sul fluminense mesoregion from 2000 to 2002 are presented and revealed the occurrence of 18 species: antillorbis nordestensis; biomphalaria glabrata; biomphalaria peregrina; biomphalaria straminea; biomphalaria tenagophila; drepanotrema anatinum; drepanotrema cimex; drepanotrema lucidum; ferrissia sp.; gundlachia ticaga; gundlachia sp ... | 2004 | 15273799 |
| differential gene expression and the effects of biomphalaria glabrata embryonic (bge) cell factors during larval schistosoma mansoni development. | 2004 | 15287597 | |
| behavior of schistosoma mansoni-induced histopathological lesions in biomphalaria glabrata submitted to ionizing radiation. | present report demonstrates that repeated radiation of schistosoma mansoni-infected biomphalaria glabrata, totaling 15,000 rads, caused a sudden, albeit transient, suppression of cercarial shedding. initially, sporocysts practically disappeared from the snail tissues. the more resistant developing cercariae presented nuclear clumping and vacuolation, before undergoing lysis. no host tissue reaction was evident at any time. thirty-four days after the last irradiation, the snails resumed cercarial ... | 2004 | 15330060 |
| polymerase chain reaction and restriction fragment length polymorphism analysis of the its2 region for differentiation of brazilian biomphalaria intermediate hosts of the schistosoma mansoni. | we sequenced the internal transcribed spacer 2 of the ribosomal dna (its2-dnar) from the three schistosoma mansoni intermediate hosts in brazil: biomphalaria glabrata, biomphalaria tenagophila and biomphalaria straminea. analysis of a restriction map from those sequences allowed us to select putative restriction enzymes able to identify the snail species under study. four restriction enzymes were used and hpaii provided simple species-specific profiles easily visualized in polyacrylamide gels. t ... | 2004 | 15334271 |
| molecular identification of symbionts from the pulmonate snail biomphalaria glabrata in brazil. | the icthyosporean, capsaspora owczarzaki, a known predator of schistosoma mansoni sporocysts in vitro, is more prevalent in laboratory-reared strains of the intermediate snail host, biomphalaria glabrata resistant to s. mansoni, than from the susceptible m line strain. we examined whether b. glabrata resistant to the nih-pr-1 strain of s. mansoni from 2 regions in brazil were also host to c. owczarzaki. symbiont presence was examined using hemolymph culturing and nested polymerase chain reaction ... | 2004 | 15357065 |
| constitutive differences in cu/zn superoxide dismutase mrna levels and activity in hemocytes of biomphalaria glabrata (mollusca) that are either susceptible or resistant to schistosoma mansoni (trematoda). | genetic strains of the snail biomphalaria glabrata vary in their resistance to the parasite schistosoma mansoni. phagocytic cells (hemocytes) circulating in the hemolymph of b. glabrata play an essential role in the snail's innate immune response. hemocytes of resistant b. glabrata kill s. mansoni in vitro via a mechanism which involves a respiratory burst. reactive oxygen species (ros), which are products of the respiratory burst, can act as mediators of both oxidative damage and of immune-rela ... | 2004 | 15383302 |
| long-term controlled field experiment on the competition between two species of biomphalaria (mollusca, basommatophora), the snail vectors of schistosoma mansoni in northeastern brazil. | a long-term controlled field experiment on the interactions of the populations of biomphalaria glabrata (target population) and b. straminea (competitor) was carried out in the county of alhandra, state of paraíba, brazil, during the period 1980 through 1989. results obtained in the current paper show that the snail b. straminea has strong competitive advantages over b. glabrata. in six out of nine streams the native population of b. glabrata were totally excluded and replaced by b. straminea. t ... | 2004 | 15448838 |
| ultrastructural study of the in vitro interaction between biomphalaria glabrata hemocytes and schistosoma mansoni miracidia. | biomphalaria glabrata and schistosoma mansoni relationship was studied by light microscopy (lm) and freeze-fracture replica technique (ffr). we observed very thin cytoplasmic extensions of hemocytes in the lm, which then surround immobilize the miracidia. ffr images showed that the contact site between hemocytes cytoplasmic extensions and the external tegumentary coat involved only superficial layers of miracidia. numerous vacuoles and filopodia were observed in the hemocyte cytoplasm, the latte ... | 2004 | 14762516 |
| representation of an immune responsive gene family encoding fibrinogen-related proteins in the freshwater mollusc biomphalaria glabrata, an intermediate host for schistosoma mansoni. | fibrinogen-related proteins (freps) are found in the hemolymph of the freshwater snail biomphalaria glabrata, are up-regulated following exposure to digenetic trematode parasites, and bind to trematode larval surfaces, suggestive of a role in internal defense. southern blot and degenerate-polymerase chain reaction (pcr) analyses were undertaken to better understand the diversity of the frep-encoding gene family. probes corresponding to the n-terminal igsf domains of specific frep gene subfamilie ... | 2004 | 15474308 |
| the initial epidemiological studies in the low endemicity schistosomiasis area in esteio, rio grande do sul, the southernmost brazilian state, 1997 to 2000. | nor biomphalaria glabrata neither schistosoma mansoni were reported from rio grande do sul, the southernmost brazilian state before 1997. their detection next to the sinos river, esteio, confirmed predictions of schistosomiasis expansion to the south. parasitological examinations both in snails and fecal samples from the human population were performed from 1997 to 2000. the last 3 out of 5 surveys were performed after a preliminar serological screening procedure in a risk group identified at a ... | 2004 | 15486639 |
| spatial distribution of schistosomiasis foci on itamaracá island, pernambuco, brazil. | acute cases of schistosomiasis have been found on the coastal area of pernambuco, brazil, due to environmental disturbances and disorderly occupation of the urban areas. this study identifies and spatially marks the main foci of the snail host species, biomphalaria glabrata on itamaracá island. the chaotic occupation of the beach resorts has favoured the emergence of transmission foci, thus exposing residents and tourists to the risk of infection. a database covering five years of epidemiologica ... | 2004 | 15486640 |
| rural tourism as risk factor for the transmission of schistosomiasis in minas gerais, brazil. | recently, the booming rural tourism in endemic areas of the state of minas gerais was identified as a contributing factor in the dissemination of the infection with schistosoma mansoni. this article presents data from six holiday resorts in a rural district approximately 100 km distant from belo horizonte, mg, brazil, where a possibly new and until now unperceived way of transmission was observed. the infection takes place in swimming pools and little ponds, which are offered to tourists and the ... | 2004 | 15486645 |
| molecular ecology of schistosoma mansoni transmission inferred from the genetic composition of larval and adult infrapopulations within intermediate and definitive hosts. | we investigated the genotypic composition of the digenetic parasite schistosoma mansoni for its adult stages within the definitive host (the wild rat, rattus rattus) and for the larval stages within the intermediate host (the snail, biomphalaria glabrata) both collected at the same transmission site. our analyses are based upon the recognition and distribution of 200 different multilocus genotypes generated by rapd markers. while intramolluscan larval infrapopulations are characterized by a low ... | 2004 | 15552402 |
| the mitochondrial genome of biomphalaria glabrata (gastropoda: basommatophora), intermediate host of schistosoma mansoni. | the complete mitochondrial (mt) genome of the gastropod biomphalaria glabrata, a major intermediate host for the human parasite schistosoma mansoni, was sequenced. the circular genome, the first determined from a basommatophoran snail, is at rich (74.6%) and the smallest mt genome (13,670 nucleotides [nt]) characterized from mollusks to date. sequences from 2 b. glabrata strains, m-line and 1742, differed by only 18 nt. phylogenetic analysis of 16s and nd1 sequences confirmed the brazilian ances ... | 2004 | 15562597 |
| identification of transcripts generated during the response of resistant biomphalaria glabrata to schistosoma mansoni infection using suppression subtractive hybridization. | suppression subtractive hybridization (ssh) was used to construct a complementary dna library enriched for transcripts more abundantly expressed in the resistant bs90 strain of biomphalaria glabrata at 12 hr postinfection with schistosoma mansoni as compared with the susceptible m-line strain under the same circumstances. one hundred and twelve clones of the library were sequenced, yielding 88 unique ssh-expressed sequence tags (ests). differential expression screening indicated that 22 of the 8 ... | 2004 | 15562603 |
| effects of schistosoma mansoni infection on inorganic elements in the snail biomphalaria glabrata. | inductively coupled plasma atomic emission spectrometry (icp-aes) was used to study element ions in whole bodies of uninfected biomphalaria glabrata snails and those experimentally infected with larval schistosoma mansoni trematodes. infected snails were analysed 8 weeks post-infection. cohort snails that were left uninfected were analysed at the same time as the infected snails. sixteen elements (aluminum, boron, barium, calcium, cadmium, copper, iron, potassium, magnesium, manganese, sodium, n ... | 2004 | 15575993 |
| specific identification of egyptian biomphalaria species and possible hybrids using the polymerase chain reaction based on nuclear and mitochondrial loci. | the snail historically implicated in the transmission of schistosoma mansoni in egypt is biomphalaria alexandrina. the problem of schistosomiasis in egypt has been complicated in recent years by the introduction of biomphalaria glabrata, which has been reported to hybridize with b. alexandrina. both introduced and hybrid snails also pose a threat with respect to s. mansoni transmission. as morphological differentiation of these snails is difficult, using three dna loci, nuclear its1 and its2, an ... | 2004 | 15652216 |
| distribution and schistosoma mansoni infection of biomphalaria glabrata in different habitats in a rural area in the jequitinhonha valley, minas gerais, brazil: environmental and epidemiological aspects. | this paper examines the distribution and infection of biomphalaria glabrata with schistosoma mansoni in all aquatic snail habitats in a rural area in the state of minas gerais, brazil, in relation to physico/biotic and behavioral factors. snail and environmental surveys were carried out semi-annually between july 2001 and november 2002 at 106 sites. collected snails were examined in the laboratory for infection. b. glabrata densities were highest in overflow ponds, irrigation ponds, springs, can ... | 2004 | 15654420 |
| gene discovery and expression analysis of immune-relevant genes from biomphalaria glabrata hemocytes. | the immune effector cells (hemocytes) of the snail host biomphalaria glabrata are known to play a key role in recognition and elimination of larval helminths such as the human blood fluke schistosoma mansoni. to identify novel immune-relevant genes, we undertook an expressed sequence tag program. a hemocyte cdna library was constructed using snails that were not exposed to a particular pathogen or parasite but maintained in non-axenic conditions. putative function could be assigned to 53% of the ... | 2004 | 15707661 |
| dispersal in a parasitic worm and its two hosts: consequence for local adaptation. | characterizing host and parasite population genetic structure and estimating gene flow among populations is essential for understanding coevolutionary interactions between hosts and parasites. we examined the population genetic structure of the trematode schistosoma mansoni and its two host species (the definitive host rattus rattus and the intermediate host biomphalaria glabrata) using microsatellite markers. parasites were sampled from rats. the study was conducted in five sites of the guadelo ... | 2005 | 15807416 |
| a conserved retinoid x receptor (rxr) from the mollusk biomphalaria glabrata transactivates transcription in the presence of retinoids. | retinoid x receptors (rxr) are members of the nuclear receptor superfamily of ligand-activated transcription factors that have been characterized in a wide variety of metazoan phyla. they act as heterodimer partners of other nuclear receptors, and in vertebrates also activate transcription as homodimers in the presence of a ligand, 9-cis retinoic acid. in order to test the hypothesis that retinoic acid signaling pathways involving rxrs are present in the lophotrochozoa, we have sought to isolate ... | 2005 | 15821117 |
| [quantitative study of metal present in the hemolymph of biomphalaria glabrata (gastropoda), infected and uninfected with schistosoma mansoni]. | we conducted a preliminary study to quantify and compare two concentrations of the same metals present in the hemolymph of snail biomphalaria glabrata. in this context, we used induction coupled plasma optical emission spectroscopy technique (icp-oes), to analyze the metals in the two samples (snails infected and not infected with schistosoma mansoni). the metals studied were: aluminum, calcium, cadmium, cobalt, chromium, copper, iron, potassium, magnesium, manganese, lead and zinc. preliminary ... | 2005 | 15821791 |
| intraspecific competition and the evolution of virulence in a parasitic trematode. | intrahost competition between parasite genotypes has been predicted to be an important force shaping parasite ecology and evolution and has been extensively cited as a mechanism for the evolution of increased parasite virulence. however, empirical evidence demonstrating the existence and nature of intraspecific competition is lacking for many parasites. here, we compared within-host competitiveness between genetic strains of schistosoma mansoni with high (high-v) or low (low-v) virulence to thei ... | 2005 | 15856697 |
| differential expression of frep genes in two strains of biomphalaria glabrata following exposure to the digenetic trematodes schistosoma mansoni and echinostoma paraensei. | fibrinogen-related proteins (freps) are hypothesized to function in non-self-recognition in the snail biomphalaria glabrata. to investigate this assumption, the expression of four members of the frep gene family was studied using quantitative pcr at 0.5-16 days following exposure of m line and bs-90 strain b. glabrata to echinostoma paraensei and schistosoma mansoni. both strains react to, but fail to eliminate e. paraensei. only the bs-90 strain is immunologically resistant to s. mansoni. both ... | 2005 | 15859234 |
| respiratory burst of biomphalaria glabrata hemocytes: schistosoma mansoni-resistant snails produce more extracellular h2o2 than susceptible snails. | the production of reactive oxygen species by hemocytes from the gastropod biomphalaria glabrata has been linked to their ability to kill the trematode parasite schistosoma mansoni. for 2 laboratory strains of the snail, 1 resistant (13-16-r1) and 1 susceptible (mo) to the pr1 strain of s. mansoni, we compared hemocyte production of extracellular hydrogen peroxide when stimulated with the protein kinase c agonist phorbol myristate acetate (pma). the time course of the pma-induced response is simi ... | 2005 | 15986600 |
| a molecular survey of biomphalaria in egypt: is b. glabrata present? | two species of biomphalaria are reported from egypt, the indigenous biomphalaria alexandrina and biomphalaria glabrata, the latter believed to be introduced during the past few decades. both are known to be excellent hosts of schistosoma mansoni, the human-infecting blood fluke common in egypt. given the concerns regarding the spread of the exotic b. glabrata, this study was carried out to get a more current picture of the status of biomphalaria in egypt. snail collections were undertaken during ... | 2005 | 16014848 |
| influence of saccharose on the development of cercariae from schistosoma mansoni strains bh and sj. | the development of cercariae from schistosoma mansoni strains bh and sj in biomphalaria glabrata and biomphalaria tenagophila treated with saccharose was studied. the molluscs were maintained in dechlorinated tap water containing 0.01% saccharose. after one week of treatment with saccharose, b. glabrata and b. tenagophila were exposed to ten s. mansoni miracidia, from bh and sj strains respectively. control snails of both species were maintained in dechlorinated tap water without saccharose and ... | 2005 | 16025902 |
| manganese superoxide dismutase from biomphalaria glabrata. | the investigation of the response of biomphalaria glabrata snails to echinostoma paraensei (digenea) at 2 days post-exposure by suppression subtractive hybridization yielded a partial sequence of the anti-oxidant enzyme manganese superoxide dismutase (mnsod). full-length mnsod (669nt) from m line and bs-90 strains of b. glabrata differed by one synonymous nucleotide replacement. b. glabrata has 1-4 mnsod loci (southern hybridization). both snail strains expressed mnsod at equal baseline levels ( ... | 2005 | 16081093 |
| [schistosomiasis mansoni in two mesoregions of the state of alagoas]. | in brazil, high levels of schistosomiasis mansoni are linked to the presence of the species biomphalaria glabrata, considered to be the main host of schistosoma mansoni in endemic areas. this work conducted a survey of 40 endemic municipalities in the state of alagoas, aiming at identifying this species and its important role in the maintenance of schistosomiasis. among the municipalities surveyed, 28 lie in the mesoregion of the leste alagoano and 12, in the mesoregion of the agreste alagoano. ... | 2005 | 16082475 |
| multi-species interactions among a commensal (chaetogaster limnaei limnaei), a parasite (schistosoma mansoni), and an aquatic snail host (biomphalaria glabrata). | this study assessed the effects of a commensal, chaetogaster limnaei limnaei, and a parasitic trematode, schistosoma mansoni, on infection patterns and life-history responses in the aquatic snail biomphalaria glabrata. prevalence of infection was significantly higher in snails that were devoid of c. limnaei limnaei relative to those that were colonized by the commensal, indicating that the oligochaete may protect the host from trematode infection. this finding appeared to be the direct result of ... | 2005 | 16108575 |
| isolation and characterization of the full-length cdna encoding a member of a novel cytochrome p450 family (cyp320a1) from the tropical freshwater snail, biomphalaria glabrata, intermediate host for schistosoma mansoni. | cytochrome p450s (cyp450s) are a family of structurally related proteins, with diverse functions, including steroid synthesis and breakdown of toxins. this paper reports the full-length sequence of a novel cyp450 gene, the first to be isolated from the tropical freshwater snail biomphalaria glabrata, an important intermediate host of schistosoma mansoni. the nucleotide sequence is 2291 bp with a predicted amino acid sequence of 584aa. the sequence demonstrates conserved cyp450 structural motifs, ... | 2005 | 16113864 |
| are biomphalaria snails resistant to schistosoma mansoni? | among biomphalaria glabrata/schistosoma mansoni snail-trematode combinations, it appears that some parasites succeed whilst others fail to infect snails. snails that become infected are termed susceptible hosts. those which are not infected are traditionally determined as 'resistant'. here the concept of b. glabrata resistance to s. mansoni is re-examined in the light of additional observations. it is suggested that, in b. glabrata/s. mansoni, compatibility is tested independently for each indiv ... | 2005 | 16153311 |
| [genetic selection of biomphalaria glabrata and biomphalaria tenagophila seeking the alteration of the susceptibility and resistance to schistosoma mansoni]. | generations of biomphalaria glabrata and biomphalaria tenagophila selected genetically for resistance and susceptibility to schistosoma mansoni of strains bh and sj were used in a study of the trematode adaptation to the intermediate host. descendants of the planorbids were obtained by self-fertilization of the mollusks that became susceptible or resistant after exposure to the miracidia of schistosoma mansoni. for biomphalaria glabrata they were obtained from the following generations: parental ... | 2005 | 16172752 |
| [geographic distribution of schistosoma mansoni transmitter snail species in state of são paulo]. | a thorough knowledge of the geographic distribution of schistosoma mansoni vector snails is indispensable for the control of schistosoma mansoni schistosomiasis and its epidemiologic surveillance. from the water masses of the state of são paulo (brazil) 8,771 lots of snails--total of 108,244 individuals of the genus biomphalaria--were captured between 1982 and 2002. these specimens are now part of the malacological collection of (superintendência de controle de endemias--são paulo). according to ... | 2005 | 16172761 |
| effects of various larval digeneans on the calcium carbonate content of the shells of helisoma trivolvis, biomphalaria glabrata, and physa sp. | the calcium carbonate concentrations in the shells of helisoma trivolvis and physa sp. naturally infected with larval trematodes and biomphalaria glabrata experimentally infected with larval trematodes were analyzed quantitatively. the larval trematode-snail relationships studied were h. trivolvis infected with larval echinostoma trivolvis and physa sp. infected with various larval digeneans, and b. glabrata infected with echinostoma caproni or schistosoma mansoni. the calcium carbonate concentr ... | 2005 | 15678354 |
| [socio-cultural and ethical factors involved in the diagnosis of schistosomiasis mansoni in an area of low endemicity]. | five annual parasitological surveys and one serological survey, respectively based on the kato-katz and free sedimentation methods and the western blot technique, were conducted in sumidouro, rio de janeiro, brazil, an endemic county for schistosomiasis. possible influences of the use of these methodologies on social, cultural, and ethical aspects of the study population were also evaluated. having the opportunity to choose the different techniques was a conclusive issue influencing participatio ... | 2005 | 15692642 |
| biomphalaria glabrata cytosolic copper/zinc superoxide dismutase (sod1) gene: association of sod1 alleles with resistance/susceptibility to schistosoma mansoni. | variation in susceptibility of the snail biomphalaria glabrata to infection by the parasite schistosoma mansoni is, at least in part, genetically determined. functional studies have demonstrated that hemocyte-mediated killing of the parasite involves hydrogen peroxide, the enzymatic product of superoxide dismutase (sod). the present study identifies alleles of the gene coding for cytosolic copper/zinc sod (sod1). the resistance/susceptibility phenotypes and sod1 genotypes were determined for 354 ... | 2006 | 16564582 |
| behavior of angiostrongylus costaricensis in planorbids. | some terrestrial mollusks are natural hosts of angiostrongylus costaricensis. in the laboratory, this nematode can be maintained in certain planorbids, which are aquatic mollusks and intermediate hosts of schistosoma mansoni. mollusks can be infected with angiostrongylus costaricensis by ingestion of or active penetration by the first-stage larvae. in this work we assessed the ability of biomphalaria glabrata to attract first-stage larvae of a. costaricensis. movement of the nematode larvae towa ... | 2006 | 16710513 |
| geographical variations in infectivity and susceptibility in the host-parasite system schistosoma mansoni/biomphalaria glabrata: no evidence for local adaptation. | we investigated local adaptation in the spatially structured natural biomphalaria glabrata/schistosoma mansoni host-parasite system in the marshy forest focus of guadeloupe using cross-transplantation experiments. we demonstrated strong and highly significant variations in susceptibility/infectivity of host and parasite populations, respectively, but found no evidence of local adaptation neither for s. mansoni nor for b. glabrata. environmental as well as genetic factors are discussed to explain ... | 2006 | 16719959 |
| the effects of temperature change on the infection rate of biomphalaria glabrata with schistosoma mansoni. | the aim of this study was to investigate the influence of temperature on the development of schistosoma mansoni infections in biomphalaria glabrata. the snails were infected at 15, 20, and 30 degrees c, and the cercarial release was analyzed after 30 and 60 days post-infection. our results showed that a decrease in the temperature has a substantial influence on the development of s. mansoni infection in b. glabrata, with significant differences (p < 0.05) between 15 and 30 degrees c. these data ... | 2006 | 16830717 |
| molluscicidal activity of solanum species of the northeast of brazil on biomphalaria glabrata. | seven species of solanum were screened for their molluscicidal properties against biomphalaria glabrata, the intermediated host of schistosoma mansoni, solanum agrarium, s. jabrense, s. melissarum, s. megalonyx, s. paludosum, s. paraibanum and s. stipulaceum. four extracts showed molluscicidal activity with lc(50) from 22 to 56 microg/ml. | 2006 | 16842935 |
| red blood with blue-blood ancestry: intriguing structure of a snail hemoglobin. | the phylogenetic enigma of snail hemoglobin, its isolated occurrence in a single gastropod family, the planorbidae, and the lack of sequence data, stimulated the present study. we present here the complete cdna and predicted amino acid sequence of two hemoglobin polypeptides from the planorbid biomphalaria glabrata (intermediate host snail for the human parasite schistosoma mansoni). both isoforms contain 13 different, cysteine-free globin domains, plus a small n-terminal nonglobin "plug" domain ... | 2006 | 16877545 |
| schistosoma mansoni excretory-secretory products stimulate a p38 signalling pathway in biomphalaria glabrata embryonic cells. | following infection with schistosoma mansoni larvae, haemocytes of resistant biomphalaria glabrata snails execute a rapid defence during which they migrate towards and encapsulate the parasites. such immediate and precise responses are thought to depend on signal transduction cascades though the signalling components involved remain largely unknown. it is proposed that mitogen-activated protein kinases may play a role in b. glabrata immune signalling, in particular p38 mitogen-activated protein ... | 2006 | 16194541 |
| in vivo and in vitro knockdown of frep2 gene expression in the snail biomphalaria glabrata using rna interference. | rna interference (rnai) is reported here for the first time for biomphalaria glabrata, the snail intermediate host for the human parasite schistosoma mansoni. the fibrinogen-related protein 2 (frep2) gene, normally expressed at increased levels following exposure to digenetic trematode parasites, such as s. mansoni or echinostoma paraensei, was targeted for knockdown. double-stranded rna (dsrna) corresponding to specific regions of the frep2 gene was introduced into snails by direct injection in ... | 2006 | 16442620 |
| identification of the boudicca and sinbad retrotransposons in the genome of the human blood fluke schistosoma haematobium. | schistosomes have a comparatively large genome, estimated for schistosoma mansoni to be about 270 megabase pairs (haploid genome). recent findings have shown that mobile genetic elements constitute significant proportions of the genomes of s. mansoni and s. japonicum. much less information is available on the genome of the third major human schistosome, s. haematobium. in order to investigate the possible evolutionary origins of the s. mansoni long terminal repeat retrotransposons boudicca and s ... | 2006 | 17072464 |
| primary culture of the region of the amebocyte-producing organ of the snail biomphalaria glabrata, the intermediate host of schistosoma mansoni. | biomphalaria glabrata snails are major hosts for the digenetic trematoda schistosoma mansoni, the causative agent of human schistosomiasis. the success or failure of the infection will be dependent on the mobilization of the molluskan internal defense system, where a major role will be played by circulating hemocytes produced by the apo (amebocyte-producing organ) of the snail. in this report, the primary culture of the apo region of b. glabrata was obtained for the first time, as well as a cont ... | 2006 | 17072476 |
| lethal and sub-lethal effects of uvb on juvenile biomphalaria glabrata (mollusca: pulmonata). | although schistosoma mansoni occurs mainly in the tropics, where intense levels of solar radiation are present, the impact of ultraviolet (uv) light on schistosome transmission is not known. the purpose of this study was to investigate potential effects of uvb (290-320nm) on juvenile biomphalaria glabrata, the snail intermediate host of s. mansoni. albino and wild-type snails were exposed to doses of uvb from uv-fluorescent lamps, and the following were measured: survival, photoreactivation (lig ... | 2006 | 16996081 |
| thin layer chromatographic analysis of glucose and maltose in estivated biomphalaria glabrata snails and those infected with schistosoma mansoni. | thin layer chromatography was used to analyze the glucose and maltose concentrations of the digestive gland-gonad complex (dgg) of uninfected-estivated biomphalaria glabrata snails and estivated b. glabrata patently infected with schistosoma mansoni. all snails were estivated in a most chamber at a relative humidity of 98+/-1% and a temperature of 23+/-1 degrees c for 14 days. carbohydrates were extracted from the dgg with 70% aqueous ethanol, and extracts were analyzed on silica gel preadsorben ... | 2006 | 17010650 |
| a bacterial artificial chromosome library for biomphalaria glabrata, intermediate snail host of schistosoma mansoni. | to provide a novel resource for analysis of the genome of biomphalaria glabrata, members of the international biomphalaria glabrata genome initiative (http://biology.unm.edu/biomphalaria-genome.html), working with the arizona genomics institute (agi) and supported by the national human genome research institute (nhgri), produced a high quality bacterial artificial chromosome (bac) library. the bb02 strain b. glabrata, a field isolate (belo horizonte, minas gerais, brasil) that is susceptible to ... | 2006 | 17308766 |
| differential lectin labelling of circulating hemocytes from biomphalaria glabrata and biomphalaria tenagophila resistant or susceptible to schistosoma mansoni infection. | lectins/carbohydrate binding can be involved in the schistosoma mansoni recognition and activation of the biomphalaria hemocytes. therefore, expression of lectin ligands on biomphalaria hemocytes would be associated with snail resistance against s. mansoni infection. to test this hypothesis, circulating hemocytes were isolated from b. glabrata bh (snail strain highy susceptible to s. mansoni), b. tenagophila cabo frio (moderate susceptibility), and b. tenagophila taim (completely resistant strai ... | 2006 | 17308768 |
| a contribution to the pathobiology of biomphalaria glabrata hemocytes. | this study attempts to investigate the relationship between the hemocytes in the two compartments: circulating peripheral lymph and the connective tissues. the hemocytes are compared with the vertebrate macrophages and constitute the principal line of defense against external aggression. the hemocytes were counted in circulating hemolymph and their phagocytic capability was evaluated in schistosoma mansoni-infected biomphalaria glabrata and the results were compared with those obtained from norm ... | 2006 | 17308769 |
| changes induced in biomphalaria glabrata (say, 1818) following trials for artificial stimulation of its internal defense system. | biomphalaria glabrata can react through different pathways to schistosoma mansoni miracidium penetration, according to the degree of resistance/susceptibility presented by different snail strains, which is a genetically determined character, resistance being the dominant feature. however, it has been observed that previous susceptible snail strain may change its reactive behavior along the course of infection, exhibiting later a pattern of cercarial shedding and histopatopathological picture com ... | 2006 | 17308770 |
| on the origin of the biomphalaria glabrata hemocytes. | a histologic, morphometric and ultrastructural study performed on biomphalaria glabrata submitted to infection with schistosoma mansoni miracidia failed to provide significant evidences that the so-called amebocyte-producing organ (apo) is really the central organ for hemocyte production. in infected snails no general reactive changes appeared in the apo, the mitoses were seen only occasionally, and the possibility of cellular hyperplasia was ruled out by morphometric measurements. under the ele ... | 2006 | 17308772 |
| freshwater snails and schistosomiasis mansoni in the state of rio de janeiro, brazil: vi--noroeste fluminense mesoregion. | in this paper, the last of a series dealing with the survey of freshwater gastropods of the state of rio de janeiro, the results of collections carried out in the noroeste fluminense mesoregion from 2002 to 2005 are presented and revealed the occurrence of 20 species: antillorbis nordestensis; biomphalaria glabrata; b. straminea; b. tenagophila; drepanotrema anatinum; d. cimex; d. depressissimum; d. lucidum; ferrissia sp.; gundlachia ticaga; gundlachia sp.; heleobia sp.; idiopyrgus sp.; lymnaea ... | 2006 | 17308776 |
| activity of praziquantel on in vitro transformed schistosoma mansoni sporocysts. | praziquantel (pzq) is effective against all the evolutive phases of schistosoma mansoni. infected biomphalaria glabrata snails have their cercarial shedding interrupted when exposed to pzq. using primary in vitro transformed sporocysts, labeled with the probe hoechst 33258 (indicator of membrane integrity), and lectin of glycine max (specific for carbohydrate of n-acetylgalactosamine membrane), we evaluated the presence of lysosomes at this evolutive phase of s. mansoni, as well as the influence ... | 2006 | 17308783 |
| interspecific antagonism and virulence in hosts exposed to two parasite species. | co-infection of host organisms by multiple parasite species has evolutionary consequences for all participants in the symbiosis. in this study, we co-exposed aquatic-snails (biomphalaria glabrata) to two of their trematode parasites, schistosoma mansoni and echinostoma caproni. in co-exposed snails, e. caproni prevalence was 63% compared to only 23% for s. mansoni. co-exposed e. caproni-infected snails exhibited reduced fecundity, higher mortality, and higher parasite reproduction (higher virule ... | 2007 | 17400242 |
| effects of aestivation and starvation on the neutral lipid and phospholipid content of biomphalaria glabrata infected with schistosoma mansoni. | the effects of aestivation or starvation on the neutral lipid and phospholipid content of biomphalaria glabrata patently infected with schistosoma mansoni were determined by high-performance thin-layer chromatography-densitometry. infected-aestivated snails were maintained in a moist chamber at 24 +/- 1 c and a relative humidity of 98 +/- 1%. infected-starved snails were maintained in artificial spring water (asw) at 23 +/- 1 c without exogenous food. infected snails (the controls) were maintain ... | 2007 | 17436935 |
| mitotic responses to injected extracts of larval and adult schistosoma mansoni in biomphalaria glabrata: effects of dose and colchicine treatment. | biomphalaria glabrata snails injected with extracts of schistosoma mansoni miracidia, mother sporocyst excretory-secretory product, cercariae, and adults, showed increased mitotic activity in histological sections of the amebocyte-producing organ (apo) relative to water-injected controls. the mitotic response was generally higher to extracts adjusted to 1.0 mg protein/ml than to a 10-fold lower concentration, although in most cases this increase was not statistically significant. colchicine trea ... | 2007 | 17436970 |
| antioxidant gene expression and function in in vitro-developing schistosoma mansoni mother sporocysts: possible role in self-protection. | the ability of the larval forms of schistosoma mansoni to invade and parasitize their molluscan host, biomphalaria glabrata, is determined by a multitude of factors. in this study we sought to elucidate the possible mechanisms by which the invading larvae are able to counteract the potentially harmful oxidative environment presented by the host upon initial miracidial infection. this was attempted by examining the gene expression profile of parasite antioxidant enzymes of the linked glutathione- ... | 2007 | 17445325 |
| high performance column liquid chromatographic analysis of selected carboxylic acids in biomphalaria glabrata patently infected with schistosoma mansoni. | high-performance liquid chromatography (hplc) was used to determine the effects of a patent schistosoma mansoni infection on certain carboxylic acids in the digestive gland gonad complex (dgg) and hemolymph of biomphalaria glabrata. an analysis of dgg samples was done using extraction with 50% locke's solution, cleanup of the extract by anion exchange solid phase extraction (spe), and ion exclusion hplc with ultraviolet detection. hemolymph was applied directly to the spe column. acetic, fumaric ... | 2007 | 17483962 |
| evaluation of the effect of oxamniquine, praziquantel and a combination of both drugs on the intramolluscan phase of schistosoma mansoni. | the activity of oxamniquine (oxa), praziquantel (pzq), and a combination of both drugs was evaluated at the intramolluscan phase of schistosoma mansoni. biomphalaria glabrata snails infected with s. mansoni were treated with 500 mg/kg oxa, 1000 mg/kg pzq or with 250 mg/kg oxa and 500 mg/kg pzq, in association, at the pre-patent and patent phases of infection. the results showed that either treatments with oxa or pzq, alone, at the pre-patent period, delayed the parasite's development, increasing ... | 2007 | 17498638 |
| nimbus (bgi): an active non-ltr retrotransposon of the schistosoma mansoni snail host biomphalaria glabrata. | the freshwater snail biomphalaria glabrata is closely associated with the transmission of human schistosomiasis. an ecologically sound method has been proposed to control schistosomiasis using genetically modified snails to displace endemic, susceptible ones. to assess the viability of this form of biological control, studies towards understanding the molecular makeup of the snail relative to the presence of endogenous mobile genetic elements are being undertaken since they can be exploited for ... | 2007 | 17521654 |
| interplay between host genetic variation and parasite transmission in the biomphalaria glabrata-schistosoma mansoni system. | genetic variability is often predicted to enhance host fitness in the face of parasitism, yet this idea is rarely tested in an experimental setting, particularly with animal hosts. to assess this question, we used a relatively resistant line of snail hosts (biomphalaria glabrata) to generate inbred and outcrossed progeny that were then either exposed or sham-exposed to the trematode parasite, schistosoma mansoni. results showed no difference in prevalence between the groups; however, large diffe ... | 2007 | 17564726 |
| is host-schistosome coevolution going anywhere? | that pathogens and hosts coevolve is a powerful concept with broad theoretical and applied implications spanning from genetic theory to the medical and veterinary sciences, particularly in the context of infectious disease epidemiology. a substantial body of theory has been developed to explore the likelihood and consequences of coevolution, but few empirical studies have been conducted to test these theories, particularly for indirectly-transmitted pathogen-host systems. we initiated replicate ... | 2007 | 17567519 |
| excretory-secretory proteome of larval schistosoma mansoni and echinostoma caproni, two parasites of biomphalaria glabrata. | schistosoma mansoni and echinostoma caproni are two trematode species that use different strategies (mimicry and immunosuppression, respectively) to interfere with the snail innate immune system. parasites excretory-secretory (es) products have been shown to play a key role in these host-parasite immune interactions. however, they remain largely uncharacterized in larval trematodes. we developed a global proteomic approach to characterize the es proteome of s. mansoni and e. caproni primary spor ... | 2007 | 17606306 |
| ki-67 is expressed in multiplying forms of schistosoma mansoni, but not in snail host tissues. | ki-67 is a protein expressed in the nucleus of several species during cell-division, being absent during the go resting phase of the cellular cycle. during attempts to disclose mitosis in the so-called " amebocyte-producing organ " in biomphalaria glabrata infected with schistosoma mansoni, the parasite multiplying forms appeared strongly marked for ki-67, while the snail tissues were completely negative. these data are worth registering to complement general data on ki-67, and to help future st ... | 2007 | 17710314 |