ISSN:
0886-1544
Keywords:
microtubules
;
chromosome movement
;
Paramecium
;
nuclear lamina
;
Life and Medical Sciences
;
Cell & Developmental Biology
Source:
Wiley InterScience Backfile Collection 1832-2000
Topics:
Biology
,
Medicine
Notes:
The micronuclear spindle apparatus in Paramecium bursaria was studied by electron microscopy during prophase, metaphase, and anaphase of the first meiotic division. During prophase, the spindle apparatus consists mostly of intermediate-like filaments, relatively few spindle microtubules, and unique cone-shaped structures termed microlamellae. Microlamellae join the ends of chromosomes to the fibrous elements of the spindle. The capacity to preserve the intermediate-like filaments is largely dependent upon the use of collidine buffer during fixation. In contrast, during metaphase and anaphase, microtubules are the dominant fibrous element of the spindle. The microtubules interact with chromosomes during these phases by joining to true kinetochores. Neither treatment with cytochalasin B or fixation with a low concentration of osmium tetroxide affects the development of intermediate filaments during prophase. Because intermediate-like filaments are abundant during prophase and microtubules are more common during metaphase and anaphase, the structural differences may reflect differences in the mechanisms for chromosome movement.
Additional Material:
12 Ill.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1002/cm.970130105