Original contribution
Estimation of water content and water mobility in the nucleus and cytoplasm of Xenopus laevis oocytes by NMR microscopy

https://doi.org/10.1016/0730-725X(94)00109-GGet rights and content

Abstract

NMR microscopy is a noninvasive approach for studying cell structure and properties. Spatially resolved measurement of the relaxation times T1 and T2 provided information on the water proton spin density and water mobility in different parts of Xenopus laevis oocytes. The spin-lattice relaxation time T1 was determined using a saturation-recovery sequence and the common spin-echo sequence with increasing repetition times, while the transverse relaxation time T2 was measured by means of the spin-echo sequence with varying echo times. From the relaxation times, the mole fractions of possible reorientational correlation times τc for different types of intracellular water were calculated according to a simple two-phase model. The values for T1, T2, and proton spin density (i.e., water content) are: nucleus ⪢ animal cytoplasm > vegetal cytoplasm. Based on the estimation of τc, nearly 90% of the nuclear water and 74.4% of the water of the animal pole was considered as free mobile water, whereas 55.5% of the water of the vegetal pole appeared as bound water.

References (31)

  • R.D. Moore et al.

    Effect of insulin on intracellular pH as observed by 31P NMR spectroscopy

  • K. Kusano et al.

    Acetylcholine receptors in the oocyte membrane

    Nature

    (1977)
  • J.B. Aguayo et al.

    Nuclear magnetic resonance imaging of a single cell

    Nature

    (1986)
  • H.K. Mild et al.

    High density cell water in amphibian eggs?

    J. Exp. Biol.

    (1979)
  • H.K. Mild et al.

    A note on the cell water density in amphibian eggs

    J. Exp. Biol.

    (1981)
  • Cited by (31)

    • Single cell spectroscopy: Noninvasive measures of small-scale structure and function

      2013, Methods
      Citation Excerpt :

      Although this review is primarily focused on spectroscopic approaches it is worth brief mention of additional spatially resolved biophysical information that can be obtained through NMR imaging (MRI). The possibilities include intracellular structural information [49], maps of water content and mobility [50], water diffusion properties [51], membrane permeability [52], and lipid-specific spin-density maps [51]. Again, due to past and current hardware limitations, single-cell studies have been performed only with the Xenopus oocytes, due to their relatively large diameter.

    • Osmotic and aging effects in caviar oocytes throughout water and lipid changes assessed by <sup>1</sup>H NMR T<inf>1</inf> and T<inf>2</inf> relaxation and MRI

      2007, Magnetic Resonance Imaging
      Citation Excerpt :

      A biexponential decay was observed for the T2 relaxation decay of both s and us samples. In agreement with previously reported data [5,14], the T1 measurements of intracellular water yielded to values approximately 50 times higher with respect to the T2 values. Indeed, as is well known, under the extreme narrowing conditions, the theory of dipolar relaxation requires nearly an equality of T1 and T2, as what was reported for pure water.

    • Subcellular in vivo<sup>1</sup>H MR spectroscopy of Xenopus laevis oocytes

      2006, Biophysical Journal
      Citation Excerpt :

      To examine the reason for this factor, we compared T2, the spin-spin relaxation times, of the methylene peak at 1.1 ppm in both compartments. Values of 14 ± 1 ms and 12 ± 0.2 ms were obtained for the animal and vegetal cytoplasm, respectively—well in agreement with previously gathered data (12,29). Our in vivo 1H spectra did not reveal metabolites other than triglycerides.

    • Picoliter <sup>1</sup> H NMR spectroscopy

      2002, Journal of Magnetic Resonance
    View all citing articles on Scopus
    View full text