Homeotic transformation of tail to hindlimbs in anuran tadpoles is a manifestation of the reprogramming of positional information in the event of tail regeneration. Such discovery of homeosis is of particular interest considering its occurrence in a vertebrate under the influence of a morphogen which represents a self-organizing system in the context of developmental and regenerative studies. This article reviews homeotic transformation of tail to hindlimbs including pelvic girdles induced by retinoic acid (RA) /vitamin A palmitate during tail regeneration under the scope of self-organization and the role of blastema as an organizer.
View Article and Find Full Text PDFLimbs are trunk quintessential in tetrapods. Their development relies on the Retinoic acid (RA) gradient in association with the Fibroblast Growth Factors (FGFs). The role of various FGFs have been probed extensively and confirmed during the induction of ectopic limbs in vertebrates.
View Article and Find Full Text PDFBackground: Leprosy (Hansen's disease) is a neglected tropical disease affecting millions of people globally. The combined formulations of dapsone, rifampicin and clofazimine (multidrug therapy, MDT) is only supportive in the early stage of detection, while "reemergence" is a significant problem. Thus, there is still a need to develop newer antileprosy molecules either of natural or semi-synthetic origin.
View Article and Find Full Text PDFBiofilms form a complex layer with defined structures, that attach on biotic or abiotic surfaces, are tough to eradicate and tend to cause some resistance against most antibiotics. Several studies confirmed that biofilm-producing bacteria exhibit higher resistance compared to the planktonic form of the same species. Antibiotic resistance factors are well understood in planktonic bacteria which is not so in case of biofilm producing forms.
View Article and Find Full Text PDFAnuran tadpoles are excellent models for regeneration studies. The tail, an organ essential for swimming for the aquatic tadpole, regenerates completely following injury or amputation. However, treatment with the morphogen, vitamin A or retinoic acid inhibits normal tail regeneration and induces homeotic transformation of tail to limbs.
View Article and Find Full Text PDFSpinal cord injury could be fatal in man and often results in irreversible medical conditions affecting mobility. However, anuran amphibians win over such pathological condition by the virtue of regeneration abilities. The tail of anuran tadpoles therefore allures researchers to study spinal cord injury and self- repair process.
View Article and Find Full Text PDFScientificWorldJournal
December 2014
Blood was analyzed from eighty (forty males and forty females) adult individuals of Polypedates teraiensis to establish reference ranges for its hematological and serum biochemical parameters. The peripheral blood cells were differentiated as erythrocytes, lymphocytes, eosinophils, neutrophils, monocytes, basophils, and thrombocytes, with similar morphology to other anurans. Morphology of blood cells did not vary according to sex.
View Article and Find Full Text PDFThe present paper describes a sequential study of the leukocyte profiles and the changes in morphometry and morphology of erythrocytes in the tadpoles of Polypedates teraiensis during their development and metamorphosis, that is, transfer from an aquatic mode to a terrestrial mode of life. Blood smears of 21 different stages (Gosner stage 26 to 46) of tadpoles were investigated. Population of erythrocytes was heterogeneous in population represented by various forms (oval, elliptical or rounded cells, comma shaped, teardrop shaped, schistocytes, senile erythrocytes, crenulated RBCs).
View Article and Find Full Text PDFProgrammed cell death during anuran tail resorption is primarily brought about by apoptosis. Cathepsin D, a lysosomal aspartyl protease, is involved in the death of tail tissues. Thus, anuran tail resorption presents an ideal model to study cathepsin-mediated cell death during vertebrate development.
View Article and Find Full Text PDFCathepsin D, an aspartyl protease, plays a key role in the metabolic degradation of intracellular proteins in an acidic milieu of lysosomes. Proteolysis plays an essential role in anuran tail regression and a wide variety of thyroid hormone induced proteolytic enzymes have been reported to be involved in the regressing tail. The present study describes the trend of specific activity of cathepsin D in the tail of different developmental stages and immunohistochemical localization of cathepsin D during degradation of various tail tissues in the tadpoles of Polypedates maculatus.
View Article and Find Full Text PDFComp Biochem Physiol B Biochem Mol Biol
March 2002
Vitamin A and its derivatives inhibit normal tail regeneration in amphibians. The most remarkable effect is the development of limbs at the cut end of the tail in anurans. Prior to ectopic limb development, there is an abnormal tail regeneration in the treated tadpoles.
View Article and Find Full Text PDFIn this study the effects of vitamin A on tadpoles of Polypedates maculatus with an amputated tail were investigated. After amputation of half the tail at the hindlimb-bud stage, tadpoles were exposed to vitamin A (palmitate) 10 IU/ml solution for 24 hr (Group I), 48 hr (II), 72 hr (III), 96 hr (IV), 120 hr (V) or 144 hr (VI). Vitamin A was deleterious to survival of the tadpoles since 10, 30 and 30% tadpoles died from Group IV, V and VI, respectively before the emergence of forelimbs.
View Article and Find Full Text PDF