ALBERT — All Library Books, journals and Electronic Records Telegrafenberg

Hits per page

hits 1 - 2 | 2 hits

Sorting

Electronic Resource

Microtubule-dependent migration of the cell nucleus toward a future leading edge in amoebae ofPhysarum polycephalum (2000)

Ueda, M. ; Kuroiwa, T. ; Matsunaga, S. ; [et al.]

Springer

Protoplasma 211 (2000), S. 172-182

add to mindlist on the mindlist

Details

ISSN: 1615-6102

Keywords: Centrosome ; Chemotaxis ; Microtubules ; Nucleus ; Pseudopod

Source: Springer Online Journal Archives 1860-2000

Topics: Biology

Notes: Summary In several cell types, an intriguing correlation exists between the position of the centrosome and the direction of cell locomotion. The centrosome is positioned between the leading edge pseudopod and the nucleus. This suggests that the polarized distribution of organelles in the cytoplasm is coupled spatially with structural and functional polarity in the cell cortex. To study cellular polarization with special interest in the roles of microtubules, we have analyzed the effects of microtubule-disrupting reagents and local laser irradiation on behaviors of both the nucleus and the centrosome in living amoebae ofPhysarum polycephalum. Physarum cells often have 2–3 pseudopods. One of the pseudopods keeps extending to become a stable leading edge while the rest retracts, a crucial step that reorients cells during locomotion. The nucleus, together with the centrosome, moves specifically toward the pseudopod that will become the leading edge. Disruption of microtubules with nocodazole randomizes positions of the nucleus, indicating the involvement of microtubules in the directional migration of the nucleus toward a specific pseudopod. The migration direction of the nucleus is reversed immediately after the UV laser is irradiated at regions between the nucleus and the future leading pseudopod. In contrast, irradiation at regions between the future tail and the nucleus does not affect nuclear migration. By immunofluorescence, we confirmed fragmentation of microtubules specifically in the irradiated region. These results suggest that the nucleus is pulled together with the centrosome toward the future leading-edge pseudopod in a microtubule-dependent manner. Microtubules seem to exert the pulling force generated in the cell cortex on the centrosome. They may serve as a mediator of shape changes initiated in the cell cortex to the organelle geometry in the endoplasm.

Type of Medium: Electronic Resource

URL: http://dx.doi.org/10.1007/BF01304485

Permalink

	Location	Call Number	Expected	Availability

Others were also interested in ...

Paper (German National Licenses)

Fulltext

Electronic Resource

Vinylhydroquinone. III. Copolymerization of vinylhydroquinone and vinyl monomers by tri-n-butylboraneDedicated to Professor Yoshio Iwakura on the occasion of his 60th birthday. (1974)

Iwabuchi, S. ; Kojima, K. ; Nakahira, T. ; [et al.]

New York : Wiley-Blackwell

Journal of Polymer Science: Polymer Chemistry Edition 12 (1974), S. 2801-2808

add to mindlist on the mindlist

Details

ISSN: 0360-6376

Keywords: Physics ; Polymer and Materials Science

Source: Wiley InterScience Backfile Collection 1832-2000

Topics: Chemistry and Pharmacology

Notes: The copolymerization of vinylhydroquinone (VHQ) and vinyl monomers, e.g., methyl methacrylate (MMA), 4-vinyl-pyridine (4VP), acrylamide (AA), and vinyl acetate (VAc), by tri-n-butylborane (TBB) was investigated in cyclohexanone at 30°C under nitrogen. VHQ is assumed to copolymerize with MMA, 4VP, and AA by vinyl polymerization. The following monomer reactivity ratios were obtained (VHQ = M2): for MMA/VHQ/TBB, r1 = 0.62, r2 = 0.17; for 4VP/VHQ/TBB, r1 = 0.57, r2 = 0.05; for AA/VHQ/TBB, r1 = 0.35, r2 = 0.08. The Q and e values of VHQ were estimated on the basis of these reactivity ratios as Q = 1.4 and e = -;1.1, which are similar to those of styrene. This suggests that VHQ behaves like styrene rather than as an inhibitor in the TBB-initiated copolymerization. No homopolymerization was observed either under nitrogen or in the presence of oxygen. The reaction mechanism is discussed.

Additional Material: 2 Ill.