Development and characterization of five novel cell lines from snubnose pompano, Trachinotus blochii (Lacepede, 1801), and their application in gene expression and virological studies.

Five novel permanent cell lines have been established from gill, heart, kidney, eye and fin of snubnose pompano, Trachinotus blochii. They were designated as snubnose pompano gill (SPG), snubnose pompano heart (SPH), snubnose pompano kidney (SPK), snubnose pompano eye (SPE) and snubnose pompano fin (SPF), respectively. All these cell lines were characterized and cryopreserved successfully at different passage levels. Cell lines were passaged every alternate day; SPG, SPH, SPK, SPE and SPF cell lines attained passage levels of 68, 74, 82, 79 and 106, respectively, since the initiation of their development in 2019. The cell lines grew well in Leibovitz's 15 medium containing 15% foetal bovine serum at 28°C. Immunophenotyping of the cell lines revealed the presence of fibronectin and pancytokeratin. No mycoplasma contamination was found. The transfection study revealed the gene expression efficiency of these cell lines by expressing the green fluorescent protein (GFP). The authentication on origin of cell lines from T. blochii was confirmed by amplification of species-specific mitochondrial cytochrome oxidase I gene. The results showed the susceptibility of these cell lines to fish nodavirus (FNV) and tilapia lake virus (TiLV) and resistance to cyprinid herpesvirus 2 (CyHV-2). The FNV infection in the cell lines was confirmed by RT-PCR, Western blot, ELISA and immunocytochemistry, while TiLV infection was confirmed by RT-PCR assay. These results revealed that these cell lines are suitable for virological and foreign gene expression studies.

A new digenetic trematode Paradiscogaster mannari n. sp. (Faustulidae) from the emperor angel fish Pomacanthus imperator from Gulf of Mannar, India.

Paradiscogaster mannari n. sp. is described from the emperor angel fish Pomacanthus imperator collected from Gulf of Mannar and maintained in the marine aquarium at CMFRI, Mandapam, India. The new species differs from other species of the genus mainly in the shape of the body, the distribution of vitelline follicles entirely in the forebody on either side of cirrus sac and in the location of testes close to posterior end of body. The various species of Paradiscogaster so far recorded is listed together with information on the hosts and geographic distribution for each species. This constitutes the first report of a digenean from the emperor angel fish.