BACKGROUND: Of the major families of long terminal repeat (LTR) retrotransposons, the Pao/BEL family is probably the least well studied. It is becoming apparent that numerous LTR retrotransposons and other mobile genetic elements have colonized the genome of the human blood fluke, Schistosoma mansoni.

RESULTS: A proviral form of Sinbad, a new LTR retrotransposon, was identified in the genome of S. mansoni. Phylogenetic analysis indicated that Sinbad belongs to one of five discreet ...

The recent release of draft genome sequences of two of the major human schistosomes has underscored the pressing need to develop functional genomics approaches for these significant pathogens. The sequence information also makes feasible genome-scale investigation of transgene integration into schistosome chromosomes. Retrovirus-mediated transduction offers a means to establish transgenic lines of schistosomes, to elucidate schistosome gene function and expression, and to advance ...

BACKGROUND: Schistosomes are trematode parasites of the phylum Platyhelminthes. They are considered the most important of the human helminth parasites in terms of morbidity and mortality. Draft genome sequences are now available for Schistosoma mansoni and Schistosoma japonicum. Non-coding RNA (ncRNA) plays a crucial role in gene expression regulation, cellular function and defense, homeostasis, and pathogenesis. The genome-wide annotation of ncRNAs is a non-trivial task unless ...

Cysteine proteinases expressed by schistosomes appear to play key roles in the digestion of host hemoglobin, the principal source of amino acid nutrients utilized by these parasites. We have shown previously that the predominant cysteine proteinase activity in soluble extracts and excretory/secretory (ES) products of adults of Schistosoma mansoni and S. japonicum is cathepsin L-like in its substrate specificity. However, biochemical analysis of the cathepsin L activity in extracts and ES ...

BACKGROUND: The liver fluke Opisthorchis viverrini infects several million people in Southeast Asia. Adult flukes live in the bile ducts of humans, where they cause hepatobiliary pathology, including cholangiocarcinoma. Here, we investigated the potential of extracellular vesicles (EVs) secreted by the fluke and defined recombinant proteins derived from EVs to generate protective immunity in a hamster vaccination-challenge model.

METHODOLOGY/PRINCIPAL FINDINGS: EVs isolated from the ...

This report presents the deduced amino acid sequence of a novel cathepsin L proteinase from Schistosoma mansoni, and describes cathepsin L-like activity in extracts of adult schistosomes. Using consensus primers specific for cysteine proteinases, gene fragments were amplified from adult S. mansoni cDNA by PCR and cloned. One of these fragments showed marked identity to Sm31, the cathepsin B cysteine proteinase of adult S. mansoni, whereas another differed from Sm31 and was employed as a ...

The genome of Schistosoma mansoni contains a proviral form of a retrovirus-like long terminal repeat (LTR) retrotransposon, designated BOUDICCA: Sequence and structural characterization of the new mobile genetic element, which was found in bacterial artificial chromosomes prepared from S. mansoni genomic DNA, revealed the presence of three putative open reading frames (ORFs) bounded by direct LTRs of 328 bp in length. ORF1 encoded a retrovirus-like major homology region and a Cys/His box ...

BACKGROUND: The liver fluke Opisthorchis viverrini is classified as a class I carcinogen due to the association between cholangiocarcinoma and chronic O. viverrini infection. During its feeding activity within the bile duct, the parasite secretes several cathepsin F cysteine proteases that may induce or contribute to the pathologies associated with hepatobiliary abnormalities.

METHODOLOGY/PRINCIPAL FINDINGS: Here, we describe the cDNA, gene organization, phylogenetic relationships, ...

More than 750 million people are at risk of infection with foodborne liver flukes. Opisthorchis viverrini is considered among the most important of these parasites, due to its strong association with cholangiocarcinoma (CCA). O. viverrini infection results in a chronic inflammatory challenge to the host, which can lead to advanced, pathogen-specific disease sequelae including obstructive jaundice, hepatomegaly, cholecystitis, as well as CCA. However, before disease sequelae are apparent, ...

BACKGROUND: It is becoming apparent that perhaps as much as half of the genome of the human blood fluke Schistosoma mansoni is constituted of mobile genetic element-related sequences. Non-long terminal repeat (LTR) retrotransposons, related to the LINE elements of mammals, comprise much of this repetitive component of the schistosome genome. Of more than 12 recognized clades of non-LTR retrotransposons, only members of the CR1, RTE, and R2 clades have been reported from the schistosome ...

BACKGROUND: Nasopharyngeal carcinoma (NPC) is a solid tumor of the head and neck. Multimodal therapy is highly effective when NPC is detected early. However, due to the location of the tumor and the absence of clinical signs, early detection is difficult, making a biomarker for the early detection of NPC a priority. The dysregulation of small non-coding RNAs (miRNAs) during carcinogenesis is the focus of much current biomarker research. Herein, we examine several miRNA discovery methods ...

The human liver fluke, Opisthorchis viverrini, induces inflammation of the hepatobiliary system. Despite being constantly exposed to inimical oxygen radicals released from inflammatory cells, the parasite survives for many years. The mechanisms by which it avoids oxidative damage are unknown. In this study, thioredoxin peroxidase (TPx), a member of the peroxiredoxin superfamily, was cloned from an O. viverrini cDNA library. O. viverrini TPx cDNA encoded a polypeptide of 212 amino acid ...

The liver fluke Opisthorchis felineus is a member of the triad of epidemiologically relevant species of the trematode family Opisthorchiidae, and the causative agent of opisthorchiasis felinea over an extensive range that spans regions of Eurasia. The International Agency for Research on Cancer classifies the infection with the liver flukes Opisthorchis viverrini and Clonorchis sinensis as group 1 agents and a major risk factor for cholangiocarcinoma. However, the carcinogenic potential ...

We characterized the consensus sequence and structure of a long terminal repeat (LTR) retrotransposon from the genome of the human blood fluke, Schistosoma japonicum, and have named this element, Gulliver. The full length, consensus Gulliver LTR retrotransposon was 4788 bp, and it was flanked at its 5'- and 3'-ends by LTRs of 259 bp. Each LTR included RNA polymerase II promoter sequences, a CAAT signal and a TATA box. Gulliver exhibited features characteristic of a functional LTR ...

The human liver fluke, Opisthorchis viverrini, infects millions of people throughout south-east Asia and is a major cause of cholangiocarcinoma, or cancer of the bile ducts. The mechanisms by which chronic infection with O. viverrini results in cholangiocarcinogenesis are multi-factorial, but one such mechanism is the secretion of parasite proteins with mitogenic properties into the bile ducts, driving cell proliferation and creating a tumorigenic environment. Using a proteomic approach, ...