Showing papers on "Nucleolar chromatin published in 2012"
Journal Article•
TL;DR: 3D reconstruction on the basis of serial ultrathin sections was used to study localization of chromatin bodies which by morphological criteria might correspond to nucleolar organizers and concluded that activity in different parts of interphase complex network-like nucleoli of D. nasutum is approximately the same.
Abstract: We showed earlier that nucleoli in interphase ciliates Didinium nasutum, appearing on single ultrathin sections as individual structures, actually are parts of more complex network-like structures in which fibrillar component is located on periphery, and granular--in the central part of a nucleolus. It is known, that nucleolar organizers in D. nasutum are represented by chromatin bodies connected with nucleoli. In this work we used 3D reconstruction on the basis of serial ultrathin sections to study localization of chromatin bodies which by morphological criteria might correspond to nucleolar organizers. Our data showed, that all such chromatin bodies settled down outside of nucleoli, near the periphery of fibrillar component. Even those chromatin bodies which on single sections looked completely surrounded by fibrillar nucleolar component, actually settled down in fibrillar component cavities open to nucleoplasm. Analysis of distribution of nucleolar chromatin bodies allowed us to conclude that activity in different parts of interphase complex network-like nucleoli of D. nasutum is approximately the same.
2 citations
TL;DR: It is concluded that different parts of the complex interfase netlike nucleoli of D. nasutum have approximately the same activity, and those chromatin bodies which appeared to be completely surrounded by the fibrillar nucleolar component on single ultrathin sections are actually settled down in nucleolus cavities open to the nucleoplasm.
Abstract: According to our computer modeling data obtained earlier, nucleoli in interphase ciliates Didinium nasutum are complex netlike structures, in which the trabeculumor lamella-shaped fibrillar component is located on the periphery, and the granular component in the central part of the nucleolus. Chromatin bodies connected with nucleoli act as the nucleolar organizers in D. nasutum. In the present work, the arrangement of all chromatin bodies, which could correspond to nucleolar organizers by morphological criteria, is studied by means of a 3D-reconstruction. It is shown that all of these chromatin bodies are localized outside the nucleoli, on the fibrillar component’s periphery. Even those chromatin bodies which appeared to be completely surrounded by the fibrillar nucleolar component on single ultrathin sections are actually settled down in nucleolus cavities open to the nucleoplasm. This proves that the RNA processing in D. nasutum nucleoli is directed toward the center of nucleoli, where the granular component is located. The analysis of the nucleolar chromatin distribution made it possible to conclude that different parts of the complex interfase netlike nucleoli of D. nasutum have approximately the same activity.
1 citations