Plasticity and reprogramming of differentiated ocular tissue of tadpoles of the frog, Euphlyctis cyanophlyctis under the influence of vitamin A.

Present study has shown that differentiated cell types may loose their definitive characteristics and acquire features of another specialized cell type. Young (3 toe stage) and mature (5 toe stage) tadpoles of the frog, Euphylictis cyanophlyctis were employed as experimental animals. Experiments were completed in two phases: in the first part of experiment, lenses were extracted from right eye balls of tadpoles and treated with vitamin A; in the second part of the experiment, meshed lentectomized eye ball tissues were implanted into the pit made on mid lateral position of the tail of young and mature tadpoles and were treated with vitamin A.

Trans-differentiation of iris pigmented epithelial cells of Euphlyctis cyanophlyctis tadpoles into lens in vitro.

Meshed pigmented iris epithelium along with neural retina of tadpoles of the frog Euphlyctis cyanophlyctis were found to undergo dedifferentiation and subsequently transdifferentiate into lens in culture medium. During lag period, depigmentation (dedifferentiation) occurred in many cells. When culture became confluent 3-4 weeks after seeding tiny lens like structures differentiated from foci of cultured pigmented iris epithelium cells.

Effect of Emblica officinalis (Gaertn) on lens regeneration in the frog, Rana cyanophlyctis (Schneider).

Emblica officinalis (Amla) accelerated cell proliferation and dedifferentiation of pigmented epithelial cells of dorsal iris and consequently induced lens regeneration in R. cyanophlyctis. Further it enhanced the percentage of lens regeneration not only in young tadpoles but also is adult frogs.

The "third eye"-- a new concept of trans-differentiation of pineal gland into median eye in amphibian tadpoles of Bufo melanostictus.

Median third eye was found to develop from transplanted pineal gland of external gill stage tadpoles in the recipient 5 toe stage tadpoles of Bufo melanostictus. Pineal gland along with a bit part of brain tissue of the donor external gill stage tadpole was cut out and transplanted into a pit made between two lateral eyes of 5 toe stage recipient tadpoles. Half of the operated tadpoles were treated with vitamin A (15 IU/ml.

Homeotic regeneration of eye in amphibian tadpoles and its enhancement by vitamin A.

After removal of both the lateral eyes of external gill stage tadpoles of the toad Bufo melanostictus, the pineal organ gets transformed into a median eye. This type of transformation occurs in tadpoles of both control and vitamin A treated groups. However, vitamin A increases the likelihood of homeotic regeneration (57% in the control group and 71% in the vitamin A treated group).

Lens regeneration in mice under the influence of vitamin A.

The effect of vitamin A has been studied on lens regeneration in young (7 days old) as well as adult mice. A longitudinal slit was made under local anesthesia in the cornea over the lens. The lens was extracted intact through the incision.

Effect of vitamin A excess on oral armature in tadpoles of toad, Bufo melanostictus (Schneider) and frog, Rana cyanophlyctis (Schneider).

Tadpoles of B. melanostictus and R. cyanophlyctis were reared in vitamin A solution.