Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound   Target Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound

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Query: EC:3.1.30.2 (endonuclease)
18,621 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

A segment of the ribosomal RNA gene of Schistosoma mansoni and a DNA fragment specific to Echinococcus granulosus, cloned in plasmids, have been used as DNA probes to assess the extent of genetic variability within E. granulosus and some distinct strains have been identified. The DNA analysis, involving restriction endonuclease digestion and Southern blot hybridization with the probes, did not demonstrate any significant genetic variation within the U.K. horse/dog or sheep/dog strains but confirmed the distinctiveness of the two strains shown in previous studies. The sheep/dog strain was shown to be cosmopolitan in its distribution and fertile bovine material originating from the United Kingdom, Kenya, Spain and India conformed to this strain by DNA hybridization. In contrast, cattle isolates from Holland produced markedly different DNA hybridization banding profiles indicating that cattle can harbour more than one strain of E. granulosus. Similarly, it was shown that goats can harbour two different strains of E. granulosus, the sheep/dog strain and a form which infects camels. The strain of E. granulosus infecting equines in Spain and Ireland is genetically identical to that infecting horses in the United Kingdom. There is also a different strain infecting pigs in Poland and Yugoslavia. This pig/dog strain appears to be very similar genetically to the forms of E. granulosus which use camels and goats as intermediate hosts and is similar, though not identical, to the variant infecting Dutch cattle. It has been shown that E. granulosus material, fixed for a prolonged period in ethanol, or lyophilized, is amenable to DNA analysis and that it is possible to characterize the DNA of a single adult worm.
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PMID:Genetic heterogeneity within Echinococcus granulosus: isolates from different hosts and geographical areas characterized with DNA probes. 255 77

Total DNAs, isolated from a range of taeniid cestodes (Taenia solium, T. saginata, T. pisiformis, T. crassiceps, T. hydatigena, T. ovis, T. multiceps and T. taeniaeformis), have been subjected to restriction enzyme digestion, Southern transfer and hybridization analysis using cloned fragments of the ribosomal RNA gene of Schistosoma mansoni. Substantial inter-specific genetic differences have been revealed on the basis of characteristic hybridization patterns for each of the taeniid cestode species. Furthermore, a random genomic DNA library has been constructed in the vector plasmid pAT153 using DNA extracted from a pig isolate (Indian origin) of T. solium. A panel of taeniid cestode DNAs including DNA from Echinococcus granulosus, has been used in conjunction with hybridization and restriction enzyme analysis to identify in the library a single recombinant plasmid with a T. solium-specific insert (coded pTS10) and two recombinant plasmids with T. solium inserts having selective specificities for T. solium and T. ovis (coded pTS17) and T. solium, T. saginata, T. ovis and T. multiceps (coded pTS28). These recombinant plasmids and the cloned fragments of the ribosomal RNA gene of S. mansoni have been used in restriction endonuclease, Southern transfer and hybridization analysis to detect intra-specific genetic variation in cysticerci of T. solium from India, Mexico and Zimbabwe. In addition, pTS10 and pTS17 have been used in a simple dot-blot assay to distinguish T. solium from T. saginata.
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PMID:Molecular cloning of Taenia solium genomic DNA and characterization of taeniid cestodes by DNA analysis. 284 36

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.
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PMID:Identification of the Echinococcus (hydatid disease) organisms using cloned DNA markers. 299 90

DNA has been prepared from adults and cercariae of Schistosoma mansoni utilizing a technique that involves centrifugation through cesium chloride. The DNA isolated from S. mansoni adults and that isolated from cercariae were found to be indistinguishable in all analyses. No modified bases were detected by chromatography or comparative endonuclease restriction. Cot analysis demonstrated that the haploid genome of S. mansoni is 0.26 pg (2.7 X 10(8) base pairs) and that the genome contains both moderately and highly repeated components. Some of the repetitive fraction of DNA consists of tandemly repeated ribosomal genes of which there are 500-1000 copies per genome (1.8-3.6% of the total DNA). Four other non-ribosomal repetitive sequences (comprising at least a further 2.0% of the total DNA) have been isolated from a DNA clone bank and their arrangement within the S. mansoni genome investigated by restriction and Southern blot analysis. These cloned segments of DNA appear in many different locations within the genome and thus are reminiscent of the interspersed DNA sequences described in higher eukaryotic organisms.
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PMID:The genome of Schistosoma mansoni: isolation of DNA, its size, bases and repetitive sequences. 618 65

The two large ribsomal RNA subunits of Schistosoma mansoni are encoded within a 10 000-base sequence, which is tandemly repeated in the schistosome genome. Restriction endonuclease digestion with Bam HI cuts the rRNA gene into three fragments, which have been clones separately in pBR322 and used to constract a physical map of the gene. The sequence encoding the smaller rRNA subunit is about 2000 bases in length and is situated on the 5' sie of the sequence encoding the larger subunit, which is about 4000 bases. Approximately 4000 bases of the rRNA gene are spacer and do not code for mature rRNA. There are approximately 100 copies of the rRNA gene per haploid genome of which about 10% exhibit length heterogeneity, as judged by the hybridization of the rDNA plasmids to restriction endonuclease digests of genomic DNA. These structural variants appear to contain additional DNA sequences at more than one site within the gene and are polymorphic within the species S. mansoni.
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PMID:The arrangement of ribosomal RNA genes in Schistosoma mansoni. Identification of polymorphic structural variants. 669 8

A fragment of the ribosomal RNA gene of Schistosoma mansoni pSM889 and two DNA fragments specific to Echinococcus granulosus pHD5 and pEG18 have been used as DNA probes to assess the extent of genetic variability within E. granulosus. The DNA analysis, including restriction endonuclease digestion and Southern blot hybridization with the probes, did not demonstrate any genetic variation among E. granulosus collected from sheep in Xinjiang, Qinghai, Gansu and Ninxia. Similarly, there was no genetic variation among E. granulosus isolates collected from yak in Qinghai and Gansu provinces. The authors deemed that the yak isolates and the sheep isolates of E. granulosus appear to belong to a same strain.
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PMID:[RFLP analysis of DNA from Echinococcus granulosus collected from four provinces/autonomous region in China]. 790 4

Genomic DNA from Schistosoma mansoni and S. japonicum adult worms was hybridized to a 32p-labelled pSM 889 probe after cleavage by restriction endonuclease BglII, BamHI, XbaI and EcoRI, or to a 32p-labelled pSM 389 probe after cleavage by EcoRI. The resulting hybridization banding patterns were significantly different between the two species. Genomic DNA from S. japonicum adult worms of Hunan, Hubei, Jiangxi, Zhejiang and Yunnan isolates was hybridized to a 32p-labelled pSM 389 probe after cleavage by EcoRI. The major hybridization bands were identical while the minor bands were more or less different among the isolates. Of them, isolates Hunan, Hubei and Zhejiang have similar minor bands while isolates Jiangxi and Yunnan have minor bands significantly different from those of the above three isolates and also markedly distinct from those of each other. These results indicate that the major hybridization banding patterns are unique to schistosome species while the minor banding patterns may serve as the basis for strain differentiation.
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PMID:[Differentiation of schistosome species and strains by DNA hybridization]. 840 68

Schistosoma mansoni genomic DNA from male and female adult worms was subjected to restriction by the isoschizomeric endonucleases HpaII and MspI, which display different sensitivities with respect to cytosine methylation. The digested DNA was hybridized with 13 S. mansoni probes. Southern blot analysis showed that there were no observable differences in the restriction patterns of the two isoschizomers and that the patterns were identical in male and female parasites. Adenine methylation was also ruled out since no differences were observed with DpnI, Sau3A1, or MboI restriction enzymes. The methylation-dependent restriction endonuclease McrBC, which cleaves DNA containing methylcytosine and will not cleave unmethylated DNA, did not digest S. mansoni genomic DNA. These results demonstrate that the genome of adult S. mansoni is not methylated.
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PMID:Lack of DNA methylation in Schistosoma mansoni. 1152 39

A new RTE-like, non-long terminal repeat retrotransposon, termed SjR2, from the human blood fluke, Schistosoma japonicum, is described. SjR2 is approximately 3.9 kb in length and is constituted of a single open reading frame encoding a polyprotein with apurinic/apyrimidinic endonuclease and reverse transcriptase domains. The open reading frame is bounded by 5'- and 3'-terminal untranslated regions and, at its 3'-terminus, SjR2 bears a short (TGAC)(3) repeat. Phylogenetic analyses based on conserved domains of reverse transcriptase or endonuclease revealed that SjR2 belonged to the RTE clade of non-long terminal repeat retrotransposons. Further, SjR2 was homologous, but probably not orthologous, to SR2 from the African blood fluke, Schistosoma mansoni; this RTE-like family of non-long terminal repeat retrotransposons appears to have arisen before the divergence of the extant schistosome species. Hybridisation analyses indicated that approximately 10,000 copies of SjR2 were dispersed throughout the S. japonicum chromosomes, accounting for up to 14% of the nuclear genome. Messenger RNAs encoding the reverse transcriptase and endonuclease domains of SjR2 were detected in several developmental stages of the schistosome, indicating that the retrotransposon was actively replicating within the genome of the parasite. Exploration of the coding and non-coding regions of SjR2 revealed two notable characteristics. First, the recombinant reverse transcriptase domain of SjR2 expressed in insect cells primed reverse transcription of SjR2 mRNA in vitro. By contrast, recombinant SjR2-endonuclease did not appear to cleave schistosome or plasmid DNA. Second, the 5'-untranslated region of SjR2 was >80% identical to the 3'-untranslated region of a schistosome heat shock protein-70 gene (hsp-70) in the antisense orientation, indicating that SjR2-like elements were probably inserted into the non-coding regions of ancestral S. japonicum HSP-70, probably after the species diverged from S. mansoni.
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PMID:Reverse transcriptase activity and untranslated region sharing of a new RTE-like, non-long terminal repeat retrotransposon from the human blood fluke, Schistosoma japonicum. 1211 99

Members of the retrotransposable element (RTE) clade of non-long terminal repeat (LTR) retrotransposon are widely distributed among eukaryote taxa, with representatives known from Caenorhabditis elegans, mammals, mosquitoes, schistosomes, and other taxa. An RTE retrotransposon has not, however, been characterized in detail from a parasitic nematode. Here, we characterize two discrete copies of an RTE-like non-LTR retrotransposon from the genome of the dog hookworm, Ancylostoma caninum. The elements were named dingo-1 and dingo-2. The full-length dingo-1 and dingo-2 elements were 3421 and 3171bp in length, respectively. They exhibited 54% nucleotide sequence identity to one another across their entire length and 40%/58% amino-acid sequence identity/similarity across their open reading frames. dingo-1 and dingo-2 exhibited hallmark structures and sequences of non-LTR retrotransposons of the RTE family including a single open reading frame encoding apurinic-apyrimidinic endonuclease (EN) and reverse transcriptase (RT), in that order. Phylogenetic analyses targeting the RT and the EN domains both confirmed that dingo-1 and dingo-2 were members of the RTE clade and that they were closely related to RTE-1 from C. elegans, to BDDF from Bos taurus and to SR2 from Schistosoma mansoni. Dot blot hybridization indicated that as many as 100-1000 copies of dingo-1 reside within the genome of A. caninum, while detection by RT-PCR of transcripts encoding dingo-like elements suggested that dingo-1 and -2 may be retrotranspositionally active within the genome of A. caninum. The dingo elements are the first retrotransposons to be characterized from a hookworm genome.
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PMID:The dingo non-long terminal repeat retrotransposons from the genome of the hookworm, Ancylostoma caninum. 1644 14


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