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At least 1,207 records · Page 67Linked to original sources
PubMed2000

Discriminant analysis of free fatty acids of some Egyptian snails as a step for schistosomiasis control: new trends.

Schistosomiasis is still the most common occupational health problem of rural workers in Egypt. The use of molluscicides, either chemical or biological, and environmental changing are the most successful methods of snail control. The new trend in Schistosoma control programs is to study the ecological factors that attract miracidium Schistosoma specific snails, to emphasizing to find out new environmental safe control methods. Since Schistosoma worms do not make fatty acids de novo, they require host lipids for survival and to complete their life cycle. Discriminate analysis of the estimated free fatty acids was done in this study in Biomphalaria alexandrina, Biomphalaria glabrata, and Bulinus truncatus, viz. Lymnaea truncatula and Physa acuta (Schistosoma intermediate and non-intermediate respectively). With the objective of determination of the biochemical difference that attract the infestation of Schistosoma miracidium to the target snails, as a step of the new control trends. Caprylic acid (C8:0), and Oleic acid (C18:1) are significantly lower in the tissues of Schistosoma intermediate snails compared to the non-intermediate snails. While, Capric acid (C10:0), Margaric acid (C17:0), and Lenoleic acid (C18:2) of the intermediate snails are significantly higher than that of non-intermediate snails. The percent of correct medical classification of snails are more than 80% according to Caprylic acid, Margaric acid, and Lenoleic acid, the other 15 fatty acids are less than 80%. These three free fatty acids could be chemoattractive of Schistosoma miracidium, and could be used as safe environmental control compounds, which needs further research.

Animals↗
PubMed1966

Field tests on two new molluscicides (Molucid and WL 8008) in the Egypt-49 project area.

In a continuing search for more effective molluscicides, tests were carried out in the Egypt-49 area on Molucid and WL 8008. Molucid, a 35% w/v solution of isobutyltriphenyl-methylamine (ICI 24223), was applied at 2 ppm for 6 hours; after the treatment, no live Bulinus truncatus, Biomphalaria alexandrina or Lymnaea caillaudi were observed for at least three months and snail densities remained low for at least seven months. Egg-masses were not affected by the treatment, however. WL 8008, N-tritylmorpholine, was applied as a 10% w/v emulsifiable concentrate in carbon tetrachloride (formulation 1), as a 20% w/v emulsifiable concentrate in tetrachlorethylene (formulation 2) or as bait. The two liquid formulations, applied at 0.25 ppm for 6 hours, gave a high initial kill, but snail densities regained their original levels within two months for Bulinus and within four months for Biomphalaria. The bait, applied at 62 lb-150 lb (28 kg-68 kg) per feddan, was ineffective. Like Molucid, WL 8008 is non-ovicidal.

Animals↗
PubMed1978

Immunodiffusion studies on Schistosoma mansoni and its host stage specific antigens. 1. Immunoelectrophoresis cross-reactions between S. mansoni adults and larval stages antigens.

IMMUNOELECTROPHORESIS was applied to evaluate the immunologic relationship between the different stages in the life cycle of Schistosoma mansoni (S.m.). The preparation of antigens and antisera was described. Separated female and male adult worms tested seem to be identical. Eggs, miracidia and cercariae from Biomphalaria glabrata and Biomphalaria alexandrina showed varying degree of cross-reactions. The maximal number of pricipitin arcs was observed, when anti-miracidia-serum was checked against all other S.m. antigens.

Animals↗
PubMed1993

Helisoma duryi: its present range of distribution and implications with schistosomiasis snails in Egypt.

The range of distribution of Helisoma duryi, a potential competitor to schistosomiasis snail vectors in Egypt, was determined in the south of Nile Delta. Results show that H. duryi was found in the River Nile, Geziret El Kerateyeen banks, Damietta and Rosetta Branches, Tawfiky and Menoufy Canals and their branches and Bassoussiya, Bahadiya and Sheshaa canals and their branches. Helisoma was found in all categories of canals and drains co-existing in various degrees with other snail species including schistosomiasis vectors (Bulinus truncatus and Biomphalaria alexandrina). The population density of H. duryi and associated B. truncatus, B. alexandrina and Physa acuta were studied for one year in three channels. Statistical analysis of results show that Helisoma has a significantly negative correlation with schistosomiasis vectors in these channels. Helisoma population showed a major peak in the warmest months of the year (July-August) thus showing recovery in population after "Winter Closure" later than Bulinus, Biomphalaria and Physa. Helisoma proved to be free of any natural trematode infection.

Animals↗
PubMed1996

Integrated control trial of schistosomiasis at Nakiwogo fishing village near Entebbe, Uganda.

Using the Kato Katz technique, 600 people living in Nakiwogo fishing village at Lake Victoria, Uganda, were examined for Schistosoma mansoni infection. The total population of this village was estimated between 1,000 and 1,500 mainly consisting of migrants from western Uganda. Of the 600 individuals in the study group, 328 people (54.7%) were found to be infected with S. mansoni. The geometric mean egg count was 422 eggs per gramme of stool. A survey of the snail intermediate hosts for S. mansoni and S. haematobium at Nakiwogo was carried out. The collected snails were tested for cercariae shedding. A significant decrease in the number of Biomphalaria choanomphala and Biomphalaria pfeifferi (52%) which both still shed cercariae and Bulinus tropicus (52.5%) could be observed. There was a lower none-significant decrease of 13.3% of the Bulinus globosus population. With a combined approach including community participation in control measures in the form of health education, sanitation, environmental management and chemotherapy, the prevalence of S. mansoni infection was reduced from 54.7% to 14.6% in the period of one year.

Adolescent↗
PubMed2000

Screening of Mediterranean Rosaceae plants for their molluscicidal and piscicidal activities.

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

Animals↗
PubMed1993

[Molluscacidal activity of spiro-alpha-methylene-gamma-butyrolactone].

The alpha-methylene-gamma-butyrolactones 1-28 were tested in vitro for molluscicidal activity against Biomphalaria glabrata. The racemic compound 25 shows the best activity. The synthesis was carried out by modified Reformatzky reaction of the corresponding carbonyl compounds and bromomethylacrylic acid ethyl ester. 7-10, 17 and 22-27 have been synthesized for the first time.

4-Butyrolactone↗
PubMed2006

Synthesis and molluscicidal activity of some 1,3,4-triaryl-5-chloropyrazole, pyrano[2,3-c]pyrazole, pyrazolylphthalazine and pyrano[2,3-d]thiazole derivatives.

2-(5-Chloro-1,3-diphenyl-1H-pyrazol-4-ylmethylene)-malononitrile 1a reacts with the arylidenes of malononitrile 2a-d to afford the triaryl-5-chloropyrazoles 3a-d, respectively. 1a reacts with the active methylene pyrazolinones 5a, b and 12a, b to afford different products 8, 9, 10, 11, and 14a, b--depending on the substitution in the pyrazole ring. Compound 1a reacts also with the pyridazinone derivative 15 to afford the phthalazinone 16, and with the thiazolinones 17a-c to afford the pyrano[2,3-d]thiazoles 20a-c, respectively. It reacts also with the malononitrile dimer 21a and with ethyl cyanoacetate dimer 21b to yield the pyrazolyl pyridines 22a, b, respectively. The synthesized compounds showed a moderate molluscicidal activity towards Biomphalaria alexandrina snails.

Animals↗
PubMed2006

Synthesis of furo-salicylanilides and their heterocyclic derivatives with anticipated molluscicidal activity.

The synthesis of new furo-salicylanilides and their heterocyclic derivatives is described. Twenty-three compounds were screened for their molluscicidal activity against Biomphalaria alexandrina snails, the intermediate host of Schistosoma mansoni. Five of the tested compounds showed no activity, while eighteen compounds showed strong to moderate activity using bayluscide as a reference.

Animals↗
PubMed2006

Synthesis and molluscicidal activity of new cinnoline and pyrano [2,3-c]pyrazole derivatives.

2-(3-Hydroxy-5,5-dimethylcyclohexylidene)malononitrile 5 undergoes an azo coupling reaction with aryldiazonium salts to afford 3-amino-2-aryl-6,6-dimethyl-8-oxo-2,6,7,8-tetrahydrocinnoline-4-carbonitriles 7. Upon reflux in acetic acid, these compounds were acetylated to give the cinnoline derivatives 9. The pyrazolones 10a, b react with 3-furfurylidene- and 3-thienylidene-malononitrile derivatives 11a, b to afford the pyrano[2,3-c]pyrazole derivatives 13a-d. These newly synthesized compounds show generally a moderate molluscicidal activity to Biomphalaria alexandrina snails.

Animals↗
PubMed1998

Detecting distant relatives of mammalian LPS-binding and lipid transport proteins.

In mammals, a family of four lipid binding proteins has been previously defined that includes two lipopolysaccharide binding proteins and two lipid transfer proteins. The first member of this family to have its three-dimensional structure determined is bactericidal/permeability-increasing protein (BPI). Using both the sequence and structure of BPI, along with recently developed sequence-sequence and sequence-structure similarity search methods, we have identified 13 distant members of the family in a diverse set of eukaryotes, including rat, chicken, Caenorhabditis elegans, and Biomphalaria galbrata. Although the sequence similarity between these 13 new members and any of the 4 original members of the BPI family is well below the "twilight zone," their high sequence-structure compatibility with BPI indicates they are likely to share its fold. These findings broaden the BPI family to include a member found in retina and brain, and suggest that a primitive member may have contained only one of the two similar domains of BPI.

Acute-Phase Proteins↗
PubMed1994

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 mapping revealed the 1F10 epitope to be between amino acids 135 and 188 of both Bg39 (Dissous et al. Molecular and Biochemical Parasitology 43, 245-256, 1990) and BgTMII (Weston and Kemp, Experimental Parasitology 76, 358-370, 1993), while the 1C1 epitope was located between amino acids 189 and 213 of BgTMII. Various invertebrate species, including members from Trematoda, Pulmonata, Annelida, and Arthropoda, were tested for cross-reactivity with the monoclonal antibodies. While the 1F10 mAb displayed broad invertebrate cross-reactivity, the 1C1 mAb cross-reactivity was restricted to schistosomes, F. hepatica, and the pulmonate snails B. glabrata and Physa sp.

Amino Acid Sequence↗
PubMed2000

Flukes without snails: advances in the in vitro cultivation of intramolluscan stages of trematodes.

In vitro cultivation of parasitic helminths, including the digenetic trematodes, has long been a valuable tool in medical and veterinary parasitology, permitting and/or facilitating the development of diagnostic reagents, chemotherapeutic agents, and vaccines and providing insights into naturally complex host-parasite interactions. In vitro cultivation of the intramolluscan stages of trematodes has been particularly challenging, given the ontogenic complexities involved in the production of multiple larval generations from germinal tissues through an asexual "budding" process. Recently, however, advanced larval development has been achieved by incorporating the Biomphalaria glabrata embryonic (Bge) cell line into cocultivation systems. Most notably, the entire intramolluscan cycle (from miracidium to cercaria) has been completed for the human blood fluke Schistosoma mansoni, while significant primary sporocyst development has been attained for several other digeneans including S. japonicum and Fascioloides magna. Here we review recent advances in the cultivation of several larval trematode species and discuss the potential use of this culture system for addressing fundamental questions of host-parasite compatibility.

Animals↗
PubMed1997

Heat-shock response in a molluscan cell line: characterization of the response and cloning of an inducible HSP70 cDNA.

Sublethal heat-shock of cells of the Bge (Biomphalaria glabrata embryonic) snail cell line resulted in increased or new expression of metabolically labeled polypeptides of approximately 21.5, 41, 70, and 74 kDa molecular mass. Regulation of this response appeared to be at the transcriptional level since a similar protein banding pattern was seen upon SDS-PAGE/fluorographic analysis of polypeptides produced by in vitro translation of total RNA from cells subjected to heat shock. Using a yeast (Saccharomyces cerevisiae) 70-kDa heat-shock protein (HSP70) probe to screen a cDNA library from heat-treated Bge cells, we isolated a full-length cDNA clone encoding a putative Bge HSP70. The cDNA was 2453 bp in length and contained an open reading frame of 1908 bp encoding a 636-amino-acid polypeptide with calculated molecular mass of 70,740 Da. Comparison of a conserved region of 209 amino acid residues revealed > 80% identity between the deduced amino acid sequence of Bge HSP70 and that of yeast (81%), the human blood fluke Schistosoma mansoni (for which B. glabrata serves as intermediate host) (81%), Drosophila (81%), human (84%), and the marine gastropod Aplysia californica (88%, 90%). In addition to the extensive sharing of sequence homology, the identification of several eukaryotic HSP70 signature sequences and an N-linked glycosylation site characteristic of cytoplasmic HSPs strongly support the identity of the Bge cDNA as encoding an authentic HSP70. Results of a Northern blot analysis, using Bge HSP70 clone-specific probes, indicated that gene expression was heat inducible and not constitutively expressed. This is the first reported sequence of an inducible HSP70 from cells originating from a freshwater gastropod and provides a first step in the development of a genetic transformation system for molluscs of medical importance.

Amino Acid Sequence↗
PubMed1975

Immunodiagnosis of human schistosomiasis using different immunoprecipitation techniques.

One hundred sera of individuals infected with Schistosoma mansoni and/or S. haematobium were examined for the presence of specific anti Schistosoma antibodies by means of different immunoprecipitation techniques: immunoelectrophoresis, immunodiffusion, immunoelectroosmophoresis (on two different supports), and electroimmunodiffusion. The immunoelectroosmophoresis proved to be superior to the other immunoprecipitation techniques, its main advantages being sensitivity, rapidity, and economic use of reagents. Precipitins against the antigen of the intermediate host, Biomphalaria glabrata, were demonstrated in 66% of the sera.

Antibodies↗
PubMed1975

Immunoprecipitation and class-specific immunofluorescence titration of human serum antibodies to Schistosoma mansoni antigens.

Twenty sera of individuals with Schistosoma mansoni infections were examined by means of immunoelectrophoresis, Indirect Flourescent Antibody (IFA) technique and the Defined Antigen Substrate Spheres (DASS) system. Immunoprecipitins against S. mansoni antigen and against antigen of the intermediate host, Biomphalaria glabrata, were demonstrated. The presence of specific anti-S. mansoni IgA, IgM, IgG and IgE antibodies were demonstrated. The presence of specific anti-S. MANSONI IgA, IgM, IgG and IgE antibodies was identified with the IFA-technique on frozen sections of adult parasites. The DASS-system proved to be more sensitive than the IFA-technique.

Adolescent↗
PubMed1986

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

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

Animals↗
PubMed1980

The development of daughter sporocysts inside the mother sporocyst of Schistosoma mansoni with special reference to the ultrastructure of the body wall.

The development of the mother sporocyst and the differentiation of the daughter sporocyst of Schistosoma mansoni in Biomphalaria pfeifferi are described. The tegumental structure of the mother sporocyst, consisting of an outer layer connected to internally situated nucleated cell bodies, forms extensions which enwrap the germinal cells. The parenchyma cells, in which the germinal cells were embedded before, degenerate. When daughter sporocyst embryos develop from germinal cells they are enveloped by a primitive epithelium which is formed by fusion of the extensions of the tegumental structure of the mother sporocyst. Somatic cells located peripherally in the developing daughter sporocyst expand and coalesce beneath the primitive epithelium to form the future outer layer of the tegumental structure of the daughter sporocyst. The primitive epithelium degenerates, the newly-formed layer looses its nuclei, and becomes connected to internally situated nucleated cell bodies. Further developments in the tegumental structure of the daughter sporocyst include the formation of microvillus-like projections, a surface coat, spines, and a basement membrane.

Animals↗