SciELO - Scientific Electronic Library Online

vol.46 issue1Acclimatization to chronic intermittent hypoxia in mine workers: a challenge to mountain medicine in ChileHigh gender -specific susceptibility to curare- a neuromuscular blocking agent author indexsubject indexarticles search
Home Pagealphabetic serial listing  

Services on Demand




Related links


Biological Research

Print version ISSN 0716-9760


LEONOVA, Olga G et al. Quantitative analysis of nucleolar chromatin distribution in the complex convoluted nucleoli of Didinium nasutum (Ciliophora). Biol. Res. [online]. 2013, vol.46, n.1, pp.69-74. ISSN 0716-9760.

We have earlier shown that the typical Didinium nasutum nucleolus is a complex convoluted branched domain, comprising a dense fibrillar component located at the periphery of the nucleolus and a granular component located in the central part. Here our main interest was to study quantitatively the spatial distribution of nucleolar chromatin structures in these convoluted nucleoli. There are no "classical" fibrillar centers in D.nasutum nucleoli. The spatial distribution of nucleolar chromatin bodies, which play the role of nucleolar organizers in the macronucleus of D.nasutum, was studied using 3D reconstructions based on serial ultrathin sections. The relative number of nucleolar chromatin bodies was determined in macronuclei of recently fed, starved D.nasutum cells and in resting cysts. This parameter is shown to correlate with the activity of the nucleolus. However, the relative number of nucleolar chromatin bodies in different regions of the same convoluted nucleolus is approximately the same. This finding suggests equal activity in different parts of the nucleolar domain and indicates the existence of some molecular mechanism enabling it to synchronize this activity in D. nasutum nucleoli. Our data show that D. nasutum nucleoli display bipartite structure. All nucleolar chromatin bodies are shown to be located outside of nucleoli, at the periphery of the fibrillar component.

Keywords : 3D reconstruction; ciliates; electron microscopy; macronucleus; nucleoli.

        · text in English     · English ( pdf )


Creative Commons License All the contents of this journal, except where otherwise noted, is licensed under a Creative Commons Attribution License