Morphology, Molecular and Chromosomal Identification of Adenoscolex oreini Fotedar, 1958 (Cestoda: Caryophyllidea) from Jammu & Kashmir, India

Authors:

Ahmad F¹, Mohi-ud-din Sofi O², Sofi TA¹*, Sheikh BA¹ and Fazili KM³

Volume 1, Issue 1

Abstract

Abstract
Introduction: Caryophyllids are unique among Eucestoda in having a monopleuroid body plan i.e., they have neither internal proglottidization nor external segmentation and have a single set of reproductive organs. They are intestinal parasites of cypriniform and siluriform freshwater fishes; intermediate hosts are aquatic annelids. Knowledge of chromosome sets of caryophyllidean tapeworms has increased within the past 40 years. To date, 23 species of all four existing families have been studied cytogenetically and karyotypes of 14 species have been completed. The diploid chromosome number of all but one species ranges from 14 to 20; Caryoaustralus sprenti, represents the exception, having only six chromosomes. Adenoscolex oreini recovered during the present investigation belongs to this order. Material and methods: The genomic DNA was isolated from the parasite of Adenoscolex oreini collected from the fish hosts of Carassius carassius; Schizothorax niger; Schizothorax curvifrons; Schizothorax labiatus; Schizothorax esocinus and Schizothorax plagiostomus from River Jhelum, River Sindh, Dal, Manasbal and Wular lakes of Kashmir valley by using standard ethanol precipation technique. The resultant DNA was separated by electrophoresis through 1.5% (w/v) agarose gel in TAE buffer stained with ethidium bromide, transilluminated under ultraviolet light and then photographed. The known size fragments of 100 bp ladder in agarose gel were used as marker. The rDNA regions spaning ITS regions were amplified by PCR. Results: During the helminthological survey of fishes in Kashmir, India, specimens of genus Adenoscolex were collected from Carassius carassius and Schizothorax spp fishes. The morphological and molecular study inferred with partial sequence of 28S rDNA and chromosome analysis confirmed the specimens as Adenoscolex oreini. Phylogenetic analysis further confirmed its taxonomic status, as it comes under the same clade formed by other same family members reported from other geographical regions. This study first time describes the molecular identification of Adenoscolex oreini from Kashmir.
Conclusion: It is concluded that Adenoscolex oreini can be differentiated on the basis of morphology, molecular and karyological features. By using molecular approach, there is marked difference between the nucleotide sequences of this tapeworm. The sequences of ITS region of 28S rDNA gene have been proved a valuable tool for taxonomic studies of closely related taxa including cestodes from fresh water bodies of fishes. The variation in size of smallest bivalent and other bivalents indicates that the somatic chromosomes will show a marked variation in the length of longest and shortest chromosome in Adenoscolex oreini. It is apparent that the systematics of the Adenoscolex and its position among the basal tapeworms (Eucestoda) is still unresolved, because of the low number of molecular characters used and very low consistency index of the trees; it is premature to speculate on some of the molecular and evolutionary implications of the present data. New material of most genera is needed for analyses of molecular data.

Keywords:

Cestode; Adenoscolex oreini; Kashmir; Carassius carassius and Schizothorax; 28S rDNA.

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