Abstract
Summary The ultrastructure of macronuclei, including replication bands, and of micronuclei are described for 5 hypotrieh species, Urostyla cristata, Holosticha sp., Styx sp., Euplotes eurystomus , and E. crassus . Macronuclei contain three major components: dispersed chromatin, condensed chromatin, and nucleoli. The dense chromatin represents the aggregation of at least most of the millions of gene-sized DNA molecules in hypotrieh macronuclei. The micronuclei in all 5 species have basically the same structure, i.e. a network of tightly packed, dense chromatin. The structure of macronuclear replication bands is similar in all 5 species. The forward zone contains tightly packed fibers ∼40 nm in diameter formed by dramatic reorganization of the chromatin at the leading border of the forward zone. An intermediate between chromatin and fibers is seen in U. cristata , consisting of finely divided particulate/fibrous material. The rear zone, in which DNA replication occurs, contain fibers ∼10 nm in diameter. Behind the rear zone the newly replicated DNA is aggregated into dense chromatin. Nucleoli remain intact as they pass through replication bands.
Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callMore From: Archiv für Protistenkunde : Protozoen, Algen, Pilze
Disclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
