ABSTRACT
The present study attempted sequencing the 18S rRNA gene of Myxoboluscatmrigalae infecting the gill lamellae of carp, Cirrhinusmrigala and compared its genetic homology and phylogenetic characteristics with 18S rRNA genes of other Myxobolus spp. The infected fish had up to 3 small, creamy white plasmodia per gill filament with 30-50 spores each. The spore size was 17.90 ± 0.70 × 7.40 ± 0.40 µm. The sporoplasm contained two large nuclei of size 0.57 ± 0.09 µm and no iodinophilous vacuole. The DNA sequence of M.catmrigalae was clustered phylogenetically with other Myxobolus spp. infecting the gills of cyprinids available in GenBank, which showed 77-87 % homogeneity. On the phylogenetic tree, M.catmrigalae (KC933944) was clustered with M.pavlovskii (HM991164) infecting the gill lamellae of silver carp, Hypophthalmichthysmolitrix. The species most closely related to M.catmrigalae in GenBank was M.pavlovskii (AF507973) infecting the gill lamellae of big head carp, Aristichthysnobilis with 87 % homogeneity. This is the first report on molecular characterization of gill lamellae infecting M. catmrigalae.
ABSTRACT
The present study was conducted from Garia, West Bengal, India to study the Prevalence, Morphology, Severity of infestation and Scanning Electron Microscopy of Myxozoan parasites in Indian Major Carps. A total of 155 fishes were examined, out of which 80 were found infected with myxozoan parasites (51.61 %) and severity of infestation varied from 0.5 to 2. Three known species Myxobolus orissae, M. carnaticus and Thelohanellus caudatus were found infecting various organs such as gills and fins of Indian major carps. Spores of the species, T. caudatus measures 12.84 ± 0.77 (11.4-14.2) µm × 8.5 ± 0.71 (7.6-9.6) µm and was elongated pyriform in shape with rounded posterior and tappering anterior end. Parietal folds were absent. The single polar capsule is rounded to oval shaped with slightly pointed anterior end and broad posterior end with size measuring 6.15 ± 2.09 (4.2-10.4) µm × 3.85 ± 1.18 (2.3-4.9) µm. M. orissae, size of the mature spore measures 15.6-19.7 (17.25) µm × 5.7-9.3 (6.70) µm and was elongated pyriform in shape. Two polar capsules are distinctly unequal. Large one measures 6.8-13.5 (8.75) × 1.4-3.1 (1.90) µm and smaller one 6.9-11.5 (7.44) × 1.7-2.4 (1.57) µm in size. Both are broadly pyriform with pointed pointed anterior end and rounded posterior end. Myxobolus carnaticus mature histozoic spores measures 8.1-12.9 (9.49) × 7.2-10 (8.27) µm are creamy white to yellow in colour tear shaped in valvular view with rounded posterior and bluntly pointed anterior ends.
