Click
here to close Hello! We notice that
you are using Internet Explorer, which is not supported by Echinobase
and may cause the site to display incorrectly. We suggest using a
current version of Chrome,
FireFox,
or Safari.
???displayArticle.abstract???
Equilibrium between mitotic microtubules and tubulin is analyzed, using birefringence of mitotic spindle to measure microtubule concentration in vivo. A newly designed temperature-controlled slide and miniature, thermostated hydrostatic pressure chamber permit rapid alteration of temperature and of pressure. Stress birefringence of the windows is minimized, and a system for rapid recording of compensation is incorporated, so that birefringence can be measured to 0.1 nm retardation every few seconds. Both temperature and pressure data yield thermodynamic values (delta H similar to 35 kcal/mol, delta S similar to 120 entropy units [eu], delta V similar to 400 ml/mol of subunit polymerized) consistent with the explanation that polymerization of tubulin is entropy driven and mediated by hydrophobic interactions. Kinetic data suggest pseudo-zero-order polymerization and depolymerization following rapid temperature shifts, and a pseudo-first-order depolymerization during anaphase at constant temperature. The equilibrium properties of the in vivo mitotic microtubules are compared with properties of isolated brain tubules.
Aronson,
Nuclear membrane fusion in fertilized Lytechinus variegatus eggs.
1973,
Pubmed
,
Echinobase
Borisy,
Microtubule assembly in vitro.
1974,
Pubmed
Bryan,
Biochemical properties of microtubules.
1974,
Pubmed
,
Echinobase
Fuseler,
Mitosis in Tilia americana endosperm.
1975,
Pubmed
Gaskin,
Turbidimetric studies of the in vitro assembly and disassembly of porcine neurotubules.
1974,
Pubmed
Haga,
Polymerization and depolymerization of microtubules in vitro as studied by flow birefringence.
1974,
Pubmed
Inoué,
Growth and lability of Chaetopterus oocyte mitotic spindles isolated in the presence of porcine brain tubulin.
1974,
Pubmed
Inoué,
Cell motility by labile association of molecules. The nature of mitotic spindle fibers and their role in chromosome movement.
1967,
Pubmed
Kresheck,
The effect of D2-O on the thermal stability of proteins. Thermodynamic parameters for the transfer of model compounds from H2-O to D2-O.
1965,
Pubmed
Olmsted,
Characterization of microtubule assembly in porcine brain extracts by viscometry.
1973,
Pubmed
Rebhun,
Regulation of size and birefringence of the in vivo mitotic apparatus.
1974,
Pubmed
,
Echinobase
Salmon,
A new miniature hydrostatic pressure chamber for microscopy. Strain-free optical glass windows facilitate phase-contrast and polarized-light microscopy of living cells. Optional fixture permits simultaneous control of pressure and temperature.
1975,
Pubmed
Stephens,
A thermodynamic analysis of mitotic spindle equilibrium at active metaphase.
1973,
Pubmed
,
Echinobase
Weisenberg,
Microtubule formation in vitro in solutions containing low calcium concentrations.
1972,
Pubmed
Weisenberg,
In vitro polymerization of microtubules into asters and spindles in homogenates of surf clam eggs.
1975,
Pubmed
