Molecular identification of a new myxozoan, Myxobolus dermiscalis n. sp. (Myxosporea) infecting scales of Labeo rohita Hamilton in Harike Wetland, Punjab (India)

Background: Harike wetland (31°08¢ N to 31°23¢ N latitudes and 74°90¢ E to 75°12¢ E longitudes) is an internationally important Ramsar site, supports rare, vulnerable and endangered plants, fish and other faunal species. Weed infestation, pollution and encroachment are considered as important threats of its biota thus time series data with respect to fish diversity, catch composition and genetic variability has an utter importance to interpret changes over time. Cyprinidae family of freshwater fishes includes carps is the largest fish family found in Harike wetland comprising around 50% of total fish composition by weight basis and among carps, Rohu (Labeo rohita) is one of the commercially important food fish species available throughout the year and preferred by consumers. As river Beas and Sutlej, two major rivers of Indus river system confluence at Harike thus possibility of variation within fish stock is very high. With this background present study was carried out to evaluate the fish biodiversity and catch composition of Harike wetland. Study also emphasized on biometrics, length –weight relationship and genetic diversity based on mitochondrial marker genes of commercially important food fish Labeo rohita. Methods: Assessment of fish catch composition and diversity were conducted in landing centre adjacent to Harike wetland through Rapid Fisheries Assessment by Market Survey (RFAMS) technique. Fin tissue samples were collected for genetic diversity analysis of L. rohita by cytochrome oxidase subunit I (COI) gene sequencing, From the fish genomic DNA a partial fragment of approximately 655bp was PCR amplified by FishF1 (5'-TCAACCAACCACAAAGACATTGGCAC-3') and FishR1 (5'-TCGACTAATCATAAAGATATCGGC AC-3') primer pair. Calculation of intraspecific mean and pairwise distances was performed by MEGA 6.0 software using the K2P parameters Results: Total 30 species of fishes were recorded from Harike wetland and these belong to 14 families and 21 genera. In L. rohita average weight (Wt), total length (TL), standard length (SL) and forked length (FL) were recorded 2600±5.64g (1700-3600 g), 58.2±5.65 cm (51.3-67.6cm), 48.0±8.54 cm (42.5-55.5cm) and 46.0±0.25 cm (38.0-54.5cm), respectively. Biometric study revealed that sufficient numbers of mature L. rohita are available in wetland. L. rohita established negative algometric growth (b= 2.701); thus species became slender as it increased in length. The pairwise distances ranged from 0.00 to 18.49% with a mean ±S.E value of 4.70%±0.40. Total of 9 haplotypes were observed in L. rohita COI sequences. The diversity in haplotype and nucletide values were observed 0.848 and 0.024, respectively. The present study states that L. rohita stocks in Harike wetland are genetically diverse.

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Molecular identification and pathogenicity study of virulent Citrobacter freundii associated with mortality of farmed Labeo rohita (Hamilton 1822), in India

Aquaculture ◽

10.1016/j.aquaculture.2021.737437 ◽

2021 ◽

pp. 737437

Author(s):

Bijay KumarBehera ◽

Prasenjit Paria ◽

Abhishek Das ◽

Basanta Kumar Das

Keyword(s):

Molecular Identification ◽

Labeo Rohita ◽

Citrobacter Freundii

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Electron microscopy in diagnostic virology

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100110702 ◽

1984 ◽

Vol 42 ◽

pp. 70-73

Author(s):

S. E. Miller

Keyword(s):

Electron Microscopy ◽

Tissue Culture ◽

Molecular Identification ◽

Point Of View ◽

Negative Stain ◽

Viral Diagnosis ◽

Electron Microscopist ◽

Diagnostic Virology

The techniques for detecting viruses are many and varied including FAT, ELISA, SPIRA, RPHA, SRH, TIA, ID, IEOP, GC (1); CF, CIE (2); Tzanck (3); EM, IEM (4); and molecular identification (5). This paper will deal with viral diagnosis by electron microscopy and will be organized from the point of view of the electron microscopist who is asked to look for an unknown agent--a consideration of the specimen and possible agents rather than from a virologist's view of comparing all the different viruses. The first step is to ascertain the specimen source and select the method of preparation, e. g. negative stain or embedment, and whether the sample should be precleared by centrifugation, concentrated, or inoculated into tissue culture. Also, knowing the type of specimen and patient symptoms will lend suggestions of possible agents and eliminate some viruses, e. g. Rotavirus will not be seen in brain, nor Rabies in stool, but preconceived notions should not prejudice the observer into missing an unlikely pathogen.

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