Histochemical studies on eggshell formation in Paramphistomum cervi (Digenea: Paramphistomatidae)

Morphological and Molecular Identification of Paramphistomum epiclitum from Buffaloes in Pakistan

INTRODUCTION

Little is known about the genetic and morphological characters of Paramphistomum epiclitum. For the first time in Pakistan, adult flukes were morphologically characterized and the sequence variation in the nuclear ribosomal DNA (rDNA) region, including the first internal transcribed spacers (ITS1) and the 5.8S gene of the Paramphistomum epiclitum were studied.

METHODS

Adult amphistomes were examined by light microscopy and sequences of ITS1 and 5.88S rDNA genes were obtained.

RESULTS

Twenty adult flukes were measured, 13.17 ± 1.19 mm in length and 5.28 ± 1.34 mm in width. Seventeen adult flukes were sequenced and high sequence variability was observed in 5' end of ITS1 region. The 5.8S and 3' end of ITS1 sequences had 100% identity among the samples. A comparative analysis revealed that different types and numbers of repeats were found within each ITS1 region. The 3' end of ITS1 region from P. epiclitum showed 98% homology with P. cervi from China and formed a subclade with genetic distance of 0.1663. The 5.8S gene showed 100% identity within Paramphistomidae family and formed a sub-clade with P. epiclitum, P. leydeni, P. cervi and Cotylophoron cotylophorum species isolated from China, India and Uruguay.

CONCLUSION

This work provides new information on morphological identity and genetics of P. epiclitum from Pakistan.

Isolation, enrichment and primary characterisation of vitelline cells from Schistosoma mansoni obtained by the organ isolation method

In the emerging era of post-genomic research on schistosomes, new methods are required to functionally analyse genes of interest in more detail. Among other tools, schistosome cell lines are needed to overcome present research constraints. Based on a recently established organ isolation protocol for adult Schistosoma mansoni, we report here on the successful enrichment of vitellarium tissue and isolation of vitelline cells. Morphological analyses performed by bright field, fluorescence, scanning and transmission electron microscopy showed typical features of S1 to S4 stage vitelline cells. In addition, molecular analyses using reverse transcription-PCR confirmed the identity of vitelline cells. Cytological and physiological studies included staining experiments with viability dyes and a neutral lipid stain, as well as calcium (Ca2+) imaging. Together they demonstrated cell viability, the possibility to define the differentiation stage of individual vitelline cells, and the suitability to investigate Ca(2+)-associated processes herein. Finally, fluorescence-activated cell sorting was shown to be a convenient way to separate and enrich S1 to S4 stage vitelline cells. In summary, these results demonstrate the expedience of the organ isolation protocol to obtain vitellarium tissue. Importantly, the protocol allows vitelline cells representing defined differentiation stages to be purified, which can be cultured in vitro and used to investigate diverse aspects of schistosome reproductive biology in the post-genomic era.

Morphology and histology of the adult Paramphistomum gracile Fischoeder, 1901

In the present study, we evaluated the histological morphology of the adult Paramphistomum (P.) gracile. Adult flukes with bodies 5~15 mm in length and 2~7 mm in width were subjected to histological analysis. Longitudinal and transversal serial-sections were stained with hematoxylin and eosin, and examined. The body surface and longitudinal section of P. gracile were also assessed using scanning electron microscopy. In this species, the anterior sucker and posterior sucker (acetabulum) were present on an anterior and posterior part of the body, respectively. The major folds were located in the areas of the anterior sucker, genital canal, and posterior sucker. The fluke membrane was spineless at the tegument surface and in the tegument tissue. Histological data showed structural-systematic characteristics of the digestive tract, reproductive tract, excretory tract, copulatory organs, connective tissues, and muscle tissues. We attempted to elucidate the histological characteristics of P. gracile that might increase the knowledge and understanding of rumen fluke morphology.