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Query: UNIPROT:P06889 (Mol)
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This report describes a method for the identification of the sex of Schistosoma mansoni cercariae using a cloned DNA probe which is female-specific. The probe is a 339 bp repeat; the sequence is presented. Cercariae from nine mono-miracidially infected snails were used in a double blind study. Mice were infected and the sex of adult worms observed. DNA was isolated from cercariae, digested with EcoRI, subjected to agarose gel electrophoresis, transferred to a matrix and hybridized with the cloned female-specific DNA probe. In all nine cases the sex of the cercariae as determined by DNA analysis agreed with the sex of the adult parasites.
Mol Biochem Parasitol 1987 Nov
PMID:A cloned DNA probe identifies the sex of Schistosoma mansoni cercariae. 282 46

An abundant 0.9 kb female-specific mRNA in Schistosoma mansoni is thought to code for an egg-shell precursor protein [Bobek et al. (1986) Proc. Natl. Acad. Sci. USA 83, 5544-5548]. This gene contains two ORFs. A recombinant plasmid was constructed that expresses a fusion protein containing a glycine- and tyrosine-rich polypeptide coded for by one of these ORFs. Antisera raised against homogenates of female, but not of male, S. mansoni recognise this fusion protein, providing direct evidence that this ORF is used by S. mansoni. In comparative Western blots of S. mansoni homogenates from males and females affinity purified antibodies that react with the fusion protein react exclusively with proteins from females, recognising a 28 kDa polypeptide and a smear of immunoreactive material probably caused by oxidative crosslinking. In immunohistology, the affinity purified antibodies react with mature vitelline cells in female schistosomes. The immunoreactive material is localised in the so-called 'vitelline droplets' that are morphologically very similar to 'shell globules', known to contain egg-shell precursors, that are found in Fasciola hepatica. In situ hybridisation shows that the eggshell precursor gene is only transcribed in immature vitelline cells and has a short half-life. Taken together, these observations provide persuasive evidence that the 0.9 kb mRNA codes for an eggshell precursor.
Mol Biochem Parasitol 1988 Nov
PMID:Identification and localisation of the products of a putative eggshell precursor gene in the vitellarium of Schistosoma mansoni. 284 44

We have isolated six independent genomic clones encoding schistosome chorion or eggshell proteins from a Schistosoma mansoni genomic library. A linkage may of five of the clones spanning 35 kilobase pair (kbp) of the S. mansoni genome was constructed. The region contained two eggshell protein genes closely linked, separated by 7.5 kbp of intergenic DNA. The two genes of the cluster were arranged in the same orientation, that is, they were transcribed from the same strand. The sixth clone probably represents a third copy of the eggshell gene that is not contained within the 35-kbp region. The 5' end of the mRNA transcribed from these genes was defined by primer extension directly off the RNA. The ATCAT cap site sequence was homologous to a silkmoth chorion PuTCATT cap site sequence, where Pu indicates any purine. DNA sequence analysis showed that there were no introns in these genes. The DNA sequences of the three genes were very homologous to each other and to a cDNA clone, pSMf61-46, differing only in three or four nucleotides. A multiple TATA box was located at positions -23 to -31, and a CAAAT sequence was located at -52 upstream of the eggshell transcription unit. Comparison of sequences in regions further upstream with silkmoth and Drosophila sequences revealed several very short elements that were shared. One such element, TCACGT, recently shown to be an essential cis-regulatory element for silkmoth chorion gene promoter function, was found at a similar position in all three organisms.
Mol Cell Biol 1988 Aug
PMID:Small gene family encoding an eggshell (chorion) protein of the human parasite Schistosoma mansoni. 285 Apr 76

A previously described cDNA clone, pSF10, of Schistosoma mansoni encoding the very dominant female specific polypeptide (FSP) has been used to characterize the gene and its expression. The gene is detectable in different isolates of S. mansoni and is estimated to be present in 3 copies per haploid genome. The gene is not sex linked and exhibits neither amplification nor rearrangement concomitant with expression. Expression of the gene by parasites maturing in hamsters is first detected after 5 weeks when the RNA is present at 1/10 the level of that of 6 week worms. Although the FSP gene is specifically and highly expressed by egg laying female worms a corresponding polypeptide produced by the cell-free translation of RNA is not detectable. It was confirmed, however, that pSF10 does indeed encode a mRNA by DNA sequence analysis. The sequence demonstrated a mRNA containing a poly(A) tail and two open reading frames. One reading contains no methionine but is very high (47%) in glycine. This amino acid composition could account for the inability to detect the gene product by cell-free translation in the presence of [35S]methionine.
Mol Biochem Parasitol 1987 Jan 15
PMID:Characterisation of the structure and expression of the gene encoding a major female specific polypeptide of Schistosoma mansoni. 288 71

Two Schistosoma mansoni proteins of 43 and 39 kDa (Sm43 and Sm39) were shown to react with rabbit antibodies produced against Biomphalaria glabrata proteins. Two-dimensional gel electrophoresis of miracidial proteins indicated that Sm43 and Sm39 were acidic proteins (pI 4.8 and 4.9 respectively) and were in vitro translated from miracidial messenger RNA in the same molecular forms. Sm43 and Sm39 were expressed by all parasite stages of S. mansoni. Using anti-Sm43 and anti-Sm39 mouse sera, we demonstrated that both parasite proteins were antigenically related and cross-reacted with a unique 39 kDa (pI 4.9) protein from B. glabrata (Bg39). Cross-reactive components were found in fresh water and land snails but not in vertebrate tissues, suggesting that the 39 kDa protein was specific for invertebrates.
Mol Biochem Parasitol 1989 Jan 01
PMID:Schistosoma mansoni and its intermediate host Biomphalaria glabrata express a common 39 kilodalton acidic protein. 291 Dec 78

To understand mechanisms involved in sex-specific gene expression in Schistosoma mansoni, a cDNA (fs800) was isolated that hybridized to an 800 nucleotide mRNA present in high levels only in mature female worms. The fs800 cDNA sequence was characterized by two long open reading frames and central stretches of repeated amino acids. Fs800 did not share similarities with other known sequences in computer searches. In situ hybridization, however, revealed that the mRNA corresponding to fs800 was found only in female vitelline cells, suggesting that the product of this gene may be involved in the production or function of eggs. Fs800 is developmentally regulated as expression of this gene is dependent on the maturity of female worms. Furthermore, during in vitro culture, when female worms are known to stop egg production, expression of fs800 selectively ceased.
Mol Biochem Parasitol 1989 Jan 15
PMID:Localization and pattern of expression of a female specific mRNA in Schistosoma mansoni. 292 41

Protective immunity has been demonstrated in experimental schistosomiasis and is also believed to occur in man. It can be mediated by antibodies from infected animals or animals immunized with attenuated organisms. Recombinant Escherichia coli synthesizing antigenic polypeptides from the three principal species of schistosome that infect man, Schistosoma mansoni, S. japonicum and S. haematobium, have been constructed. Libraries of adult worm cDNA were prepared from each species in the expression vector lambda gt 11 and directly screened with antibodies from animals experimentally immunized with S. mansoni and S. japonicum and from humans infected with S. haematobium. The S. mansoni clones have been analysed in greatest detail. At least four different types of clones were identified. All the detected recombinant polypeptide antigens were recognised by antibodies from chronically infected mice and most were also recognised by antibodies from mice immunized with attenuated cercariae and anti-surface membrane antibodies. Clones synthesizing species-specific antigens for both S. mansoni and S. japonicum were identified by simultaneous screening of both libraries. At least three types of S. haematobium clones were identified by screening with human infection serum, most of which were species-specific. All the antigens were in the form of fusion peptides with E. coli beta-galactosidase and their expression was induced by isopropylthiogalactopyranoside. Since known protective monoclonal antibodies recognise highly glycosylated membrane proteins which cannot be identified in the form of nascent polypeptides, the direct identification of polypeptide antigens defined by their reactivity, as reported here, is an essential step in producing reagents by recombinant DNA technology, suitable for vaccination and diagnosis.
Mol Biochem Parasitol 1986 Feb
PMID:Adult schistosome cDNA libraries as a source of antigens for the study of experimental and human schistosomiasis. 293 4

A cDNA library was constructed from the mRNA of adult worms of Schistosoma mansoni, in the expression vector lambda gt11. This library was screened with a pool of sera raised against either soluble egg antigens or purified schistosomulum tegumental membranes. An antiserum raised against the fusion protein of one clone immunoprecipitated a 45 kDa polypeptide from the in vitro translation products of adult worm mRNA and recognised a 50 kDa antigen in homogenates of adult worms. This serum gave positive fluorescence of the surface of schistosomula in indirect immunofluorescence assays and was able to mediate killing of schistosomula by human eosinophils in vitro, suggesting that this clone contained part of a gene encoding a surface antigen.
Mol Biochem Parasitol 1988 Jul
PMID:Cloning of the gene encoding a 50 kilodalton potential surface antigen of Schistosoma mansoni. 296 55

Cloned DNA fragments of the ribosomal RNA gene of Schistosoma mansoni hybridise strongly to Echinococcus DNA following restriction endonuclease and Southern transfer analysis. Individuals within a strain of E. granulosus exhibit identical patterns of hybridisation. However, the hybridisation patterns show significant differences between E. granulosus and E. multilocularis, and between the horse and sheep strains of E. granulosus. This technique represents a powerful, additional method for the identification and characterisation of new isolates of E. granulosus and E. multilocularis.
Mol Biochem Parasitol 1985 Nov
PMID:Identification of the Echinococcus (hydatid disease) organisms using cloned DNA markers. 299 90

The ribosomal RNA (rRNA) gene units of Schistosoma mansoni (lateral spined eggs) and six species of schistosomes with terminal spined eggs (S. haematobium, S. curassoni, S. bovis, S. intercalatum, S. margrebowiei and S. mattheei) have been studied. The schistosome rRNA gene unit consists of a regular interspersion of the two genes encoding the large and small rRNA units with two spacers. The large spacer is not transcribed while the small spacer is part of the transcription unit. Variation in the rRNA gene unit of the species studied is demonstrated and takes three forms: First, variation in DNA sequence leads to both reduced homology in the spacer regions between species and loss or gain of restriction sites. Second, variation in the length of the transcribed spacer is demonstrated and DNA insertions of 0.2 kilobases (kb) and 0.1 kb are observed in S. mattheei and S. margrebowiei, respectively. Third, the length of the non-transcribed spacer region varies between species. S. haematobium has a 0.5 kb deletion in this region, while that of S. margrebowiei contains varying numbers of a 0.4 kb DNA insert. These interspecific variations have been shown to be conserved within species. Analysis of the rRNA genes by DNA hybridisation techniques therefore serves as a means of species identification, whereby it is possible to differentiate S. haematobium from other schistosome species with terminal spined eggs. Similarly, S. margrebowiei and S. mattheei may be clearly distinguished, although no major variation has been detected between S. curassoni, S. bovis and S. intercalatum. All these species differ from S. mansoni by the absence of certain restriction sites in the non-transcribed spacer.
Mol Biochem Parasitol 1986 Aug
PMID:Differentiation of Schistosoma haematobium from related species using cloned ribosomal RNA gene probes. 301 58


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