Effects of physiologic challenge on the ADC of intracellular water in the Xenopus oocyte.
The biophysical determinants of the intracellular water apparent diffusion coefficient (ADC) in mammalian tissues are poorly understood. Model systems that are more amenable to physical measurements may provide insights into the behavior of more complex systems. Toward that end, we used MRI to evaluate the effects of altered microtubule concentration, nuclear breakdown, and ATP depletion on intracellular water ADC in the Xenopus oocyte. Water ADC did not change in response to polymerization of microtubules with taxol or depolymerization with nocodazole. Water ADC did not change following the breakdown of the nucleus in healthy cells. Short-term depletion of ATP (approximately 20% of normal levels following 4 hr of exposure to sodium azide and 2-deoxy-D-glucose) was not associated with a change in intracellular ADC. Long-term depletion of ATP (approximately 20% of normal levels following 2 days of exposure to antimycin A) was associated with a significant decrease in intracellular water ADC. These findings suggest that intracellular water diffusion in oocytes is not dependent on the state of microtubule polymerization or short-term ATP depletion, although long-term ATP depletion is associated with changes that lead to a decrease in intracellular water ADC.
Sehy
Jonathan V
JV
Program in Molecular Cell Biology, Washington University, St. Louis, Missouri, USA.
Zhao
Lin
L
Xu
Junqian
J
Rayala
Heidi J
HJ
Ackerman
Joseph J H
JJ
Neil
Jeffrey J
JJ
D000255:Adenosine Triphosphate / Q000378:metabolism; D000818:Animals; D015153:Blotting, Western; D004058:Diffusion; D008279:Magnetic Resonance Imaging / Q000379:methods*; D015739:Nocodazole / Q000494:pharmacology; D009865:Oocytes / Q000378:metabolism*; D012044:Regression Analysis; D019810:Sodium Azide / Q000494:pharmacology; D014404:Tubulin / Q000378:metabolism; D014867:Water / Q000378:metabolism*; D014981:Xenopus
D014404:Tubulin; D014867:Water; D000255:Adenosine Triphosphate; D019810:Sodium Azide; D015739:Nocodazole