Differences in Hydration State of Nucleus and Cytoplasm of the Amphibian Oocyte

Morrill, Gene A.; Kostellow, Adele B.; Osterlow, K; Gupta, Raj K.

doi:10.1007/s002329900108

Cited by 7 publications

(8 citation statements)

References 14 publications

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“…Recent microimaging studies by Grant et al. (4, 5), Sehy et al (6 -8, 10), Minard et al (9), and Morrill et al (11) involving the L7 Aplysia neuron and the X. leavis oocyte have used the volume coils successfully to achieve spatial resolution similar to ours, but often at much longer acquisition times. In addition, a key aspect of our work is the ability to select the optimal depth of imaging plane by varying the applied pulse power.…”

Section: Discussionsupporting

confidence: 50%

“…Additional benefits of using planar coils instead of volume coils occur in studies where the samples cannot be easily loaded or well contained within a volume coil, such as cell cultures, distributed cellular clusters, and noncylindrical implantable biocapsules. Recent microimaging studies by Grant et al (4,5), Sehy et al (6 -8, 10), Minard et al (9), and Morrill et al (11) involving the L7 Aplysia neuron and the X. leavis oocyte have used the volume coils successfully to achieve spatial resolution similar to ours, but often at much longer acquisition times. In addition, a key aspect of our work is the ability to select the optimal depth of imaging plane by varying the applied pulse power.…”

Section: Discussionmentioning

confidence: 52%

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NMR spiral surface microcoils: Applications

Gimi

Eroglu

Leoni

et al. 2003

Concepts Magn Reson

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ABSTRACT:We describe the use of planar submillimeter diameter radio frequency (RF) microcoils at 500 MHz (11.74 T) to image biologic samples, specifically late-stage frog oocytes (typical diameter 750 -1000 m) and isolated rat pancreatic islets (typical diameter 150 -200 m). For the frog oocyte we obtained a 25 ϫ 25 m in-plane resolution on a 100 m slice in 34 min, and for the pancreatic islets we obtained a 14 ϫ 14 m in-plane resolution on a 100-m slice in 68 min. These results demonstrate that it is possible to obtain images of living cells with high temporal and spatial resolution under conditions where viability in maintained and functional stimulation is possible. The extension of these studies to smaller diameter microcoils or arrays of microcoils may allow magnetic resonance imaging to be performed on individual cells in culture, and could lead to in vivo assessment of cell function within biocapsules or tissue implants.

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Section: Discussionsupporting

confidence: 50%

Section: Discussionmentioning

confidence: 52%

NMR spiral surface microcoils: Applications

Gimi

Eroglu

Leoni

et al. 2003

Concepts Magn Reson

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“…The difference in the pH levels in the peroxisomal lumen and in surrounding cytoplasm may be created by the mechanism known as a Donnan equilibrium [41,42]. This phenomenon is responsible, while only partially, for the maintenance of an acid pH in lysosomes [43] and for some other cellular parameters [44,45]. The presence of charged macromolecules (proteins) in peroxisomes and the low permeability of mammalian peroxisomal membrane to 'bulky' solutes such as cofactors and ATP, which are mainly charged compounds, may be responsible for the formation of a pH gradient between the peroxisomal lumen and the cytoplasm.…”

Section: Discussionmentioning

confidence: 99%

Solute traffic across mammalian peroxisomal membrane – single channel conductance monitoring reveals pore-forming activities in peroxisomes

Antonenkov

Rokka

Sormunen

et al. 2005

Cell. Mol. Life Sci.

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Mouse liver peroxisomes were isolated by centrifugation in a self-generated Percoll gradient followed by an Optiprep density gradient centrifugation. Peroxisomes contributed 90-96% of the total protein content in the fraction, as confi rmed by marker enzyme assays, protein pattern in SDS-PAGE, immunoblotting, and electron microscopy. Solubilized peroxisomal membrane proteins were reconstituted into a planar lipid bilayer. A singlechannel conductance monitoring of the reconstituted lipid bilayer revealed the presence of two pore-forming components with a conductance in 1 M KCl of 1.3 nS and 2.5 nS. Control experiments with fractions enriched in mitochondria, lysosomes, and fragments of endoplasmic reticulum showed that the peroxisomal channel-forming activities were not due to admixture of isolated peroxisomes with other cellular organelles. The peroxisomal channels were well preserved in membrane preparations but became unstable after solubilization from the membranes by detergent. * Corresponding authors.Peroxisomes are ubiquitous organelles which contain enzymes and other proteins participating in different metabolic pathways such as a-and b-oxidation of fatty acids, synthesis of bile acids, plasmalogens, and waxes, and oxidation of L-a-hydroxy acids, polyamines, purines, and some amino acids [1][2][3]. The importance of peroxisomes for cell metabolism is emphasized by the existence of a group of inherited diseases (Zellweger syndrome, neonatal adrenoleukodystrophy, infantile Refsum's disease, rhizomelic chondrodysplasia punctata) caused by impairment of one or more peroxisomal functions [2,4]. Peroxisomes consist of a matrix containing mostly soluble proteins which is surrounded by a single membrane [1]. The carbon fl uxes through peroxisomal pathways require a continuous metabolite crossing of the peroxisomal membrane. A long-standing and still unresolved problem in the physiology of mammalian peroxisomes is the role of the membrane of these organelles as a permeability barrier to solute molecules [reviewed in refs. 3, 5, 6]. A key question is whether metabolites are transferred across the membrane by specifi c protein translocators, as in the case of inner mitochondrial membrane, or whether

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“…but the chemical thermodynamic predictions show the nuclear proteins favored by relatively oxidizing conditions. Studies using nuclear magnetic resonance (NMR) showing that the hydration state of the nucleus is higher than the cytoplasm [16,13] bring into question the prediction consistent with Fig. 1e that the formation of the nuclear proteins is favored relative to their cytoplasmic counterparts by decreasing activity of water.…”

Section: Comparison With Subcellular Redox Measurementsmentioning

confidence: 98%

“…RMSD values were calculated using Eqn. (13), and ρ denotes the Spearman rank correlation coefficient, calculated using Eqn. (14).…”

Section: Relative Abundances Of Proteins Within Compartmentsmentioning

confidence: 99%