ULTRASTRUCTURAL CHANGES IN REGRESSING TAIL MUSCLES OF XENOPUS LARVAE AT METAMORPHOSIS

Ultrastructural Changes in Regressing Tail Muscles of Xenopus Larvae at Metamorphosis

One of the duplicated matrix metalloproteinase-9 genes is expressed in regressing tail during anuran metamorphosis.

The drastic morphological changes of the tadpole are induced during the climax of anuran metamorphosis, when the concentration of endogenous thyroid hormone is maximal. The tadpole tail, which is twice as long as the body, shortens rapidly and disappears completely in several days. We isolated a cDNA clone, designated as Xl MMP-9TH, similar to the previously reported Xenopus laevis MMP-9 gene, ...

Remodeling the exocrine pancreas at metamorphosis in Xenopus laevis.

At metamorphosis the Xenopus laevis tadpole exocrine pancreas remodels in two stages. At the climax of metamorphosis thyroid hormone (TH) induces dedifferentiation of the entire exocrine pancreas to a progenitor state. The organ shrinks to 20% of its size, and approximately 40% of its cells die. The acinar cells lose their zymogen granules and approximately 75% of their RNA. The mRNAs that enco...

The lateral line system at metamorphosis in Xenopus laevis (Daudin).

Marked changes in the anatomy of the lateral line system occur during the metamorphosis of Xenopus. The distribution of rows differs in larva and adult and the orientation and number of organs are modified at metamorphosis. Larval plaques are functional, as shown by recording from their nerves. Two classes of cells with polarized cilia are present in the tadpole well before the orientation of i...

Ultrastructural changes in regressing equine sarcoid tumours--mysterious role of mitochondria.

Mitochondrial changes of healing sarcoids were followed in 17 affected horses. Biopsies of this fibroblastic skin tumour were collected both before and during the treatment and tumour regression. The therapy consisted of the partial excision of tumours, repeated immunizations with autogenous polymerized tumour particles and supportive dietary treatment with stannic chloride and folic acid. Pres...