Vol 43, No 1 (2005)
Original paper
Published online: 2011-08-19
Stereological analysis of mitochondria in embryos of Rana temporaria and Bufo bufo during cleavage
Folia Histochem Cytobiol 2005;43(1):57-63.
Abstract
Total numbers of mitochondria and their morphology have been quantitatively determined in mature oocytes and
in cleaving embryos of two anuran species Rana temporaria and Bufo bufo using stereological methods. Surface densities of
inner mitochondrial membranes for both studied species during cleavage ranged from 5.43 m2/cm3 to 7.53 m2/cm3, whereas
volume densities of mitochondria did not exceed 1.65%. Since values of these parameters were low, thus embryos during
cleavage may be considered as metabolically "silent". Transition of ultrastructural morphology of mitochondria towards that
characterising actively respiring organelles occurs at stage 9 for R. temporaria and at stage 8 for B. bufo, correlated with
blastula-gastrula and mid-blastula transition, respectively. The total numbers of mitochondria N(c) in mature oocytes are as
high as 114.8 and 107.2 millions for R. temporaria and B. bufo, respectively, and during cleavage at late blastula stages they
increase to 300 millions for both species under study. We suggest that an undefined mechanism might eliminate during cleavage
those amphibian embryos which contain small number of mitochondria and low levels of nutrient substances.
Keywords: MitochondriaEmbryoCleavageRanaBufoStereology
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