Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “Amphibia”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 739 records · Page 41Linked to original sources
PubMedDate not supplied

[Specific growth rate and the rate of energy metabolism in the ontogenesis of axolotl, Ambystoma mexicanum (Amphibia: Ambystomatidae)].

Concordant changes in the rate of energy metabolism and specific growth rate of axolotls have been revealed. Several periods of ontogeny are distinguished, which differ in the ratio of energy metabolism to body weight and, therefore, are described by different allometric equations. It is suggested that the specific growth rate of an animal determines the type of dependence of energy metabolism on body weight.

Ambystoma mexicanum↗
PubMedDate not supplied

[Comparison of variability of Rana temporaria (Amphibia, Anura) gastrula from different populations developing under the conditions of antropogenic pollution].

The gastrulation of Rana temporaria embryos was studied at the natural spawning sites of Moscow city and Moscow district by means of morphometric analysis. We demonstrated that anthropogenic pollution plays an important role in morphogenesis of Anura. The measurements of embryos from the Moscow ponds made it possible to show an increased variability of gastrulation. Moreover, the level of gastrulation variability depends on the degree of pollution of a spawning pond and is coupled with increased correlations between the morphological features. This increase of correlations could be due to: (1) an increased number of correlating features (appearance of new correlations) and (2) strengthening of the existing correlations. The first way makes the gastrulation process more coordinated, and the second one causes the appearance of morphological structures, which are normally formed only at the next developmental stages.

Adaptation, Physiological↗
PubMedDate not supplied

An ultrastructural study of sperm of the genus Bufo (Amphibia, Anura, Bufonidae).

The sperm ultrastructure of Bufo schineideri and B. granulosus consists of entwined seminiferous tubules formed by groups of germ cells and Sertoli cells. The spermatozoa of B. schineideri and B. granulosus measure about 66.7 microm and 85.4 microm in length, respectively. The head measures approximately 24.8 microm in B. schineideri and 17.7 microm in B. granulosus and consists of a single vesicle acrosomal, subacrosomal cone and nucleus. The midpiece measures approximately 3.8 microm in B. schineideri and 2.5 microm in B. granulosus and presents a mitochondrial collar around the tail. The tail consists of a typical axoneme, 9 + 2 microtubules, paraxonemal rod, axial sheath and axial fiber. The axial fiber extends through an electrondense structure that supports the undulating membrane. The structure and ultrastructure of the spermatozoa of the species here described are similar to the majority of sperm found in the other bufonids and may be a contribution for future phylogenetic analysis.

Acrosome↗