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Results for “Cryo-ET”

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4 recordsLinked to original sources
PubMed2005

Development of severe ovarian hyperstimulation syndrome after inadvertent stimulation with a gonadotropin-releasing hormone agonist and human menopausal gonadotropin in a pre-existing early pregnancy.

OBJECTIVE: To report a case of severe ovarian hyperstimulation syndrome (OHSS) after inadvertent GnRH long protocol/hMG stimulation in a pre-existing early pregnancy. DESIGN: Case report. SETTING: Private infertility clinic. PATIENT(S): A 28-year-old woman who conceived spontaneously following IVF and cryo-embryo transfer (cryo-ET). INTERVENTION(S): IVF/intracytoplasmic sperm injection (ICSI), cryo-ET, analgesia, and forced diuresis. MAIN OUTCOME MEASURE(S): Viable pregnancy. RESULT(S): Viable pregnancy with OHSS despite inadvertent administration of GnRH-agonist, stimulation with hMG, and ET in a pre-existing pregnancy. CONCLUSION(S): Observation of follicle development following stimulation during pregnancy with low quantity and poor quality oocytes combined with abnormal endometrium.

Adult↗
PubMed2004

New insights into the structural organization of eukaryotic and prokaryotic cytoskeletons using cryo-electron tomography.

Cryo-electron tomography (cryo-ET) is an emerging imaging technology that combines the potential of three-dimensional (3-D) imaging at molecular resolution (<5 nm) with a close-to-life preservation of the specimen. In conjunction with pattern recognition techniques, it enables us to map the molecular landscape inside cells. The application of cryo-ET to intact cells provides novel insights into the structure and the spatial organization of the cytoskeleton in prokaryotic and eukaryotic cells.

Actin Cytoskeleton↗
PubMed2005

Structural studies by electron tomography: from cells to molecules.

Electron tomography (ET) is uniquely suited to obtain three-dimensional reconstructions of pleomorphic structures, such as cells, organelles or supramolecular assemblies. Although the principles of ET have been known for decades, its use has gathered momentum only in recent years, thanks to technological advances and its combination with improved specimen preparation techniques. The rapid freezing/freeze-substitution preparation is applicable to whole cells and tissues, and it is the method of choice for ET investigations of cellular ultrastructure. The frozen-hydrated preparation provides the best possible structural preservation and allows the imaging of molecules, complexes, and supramolecular assemblies in their native state and their natural environment. Devoid of staining and chemical fixation artifacts, cryo-ET provides a faithful representation of both the surface and internal structure of molecules. In combination with advanced computational methods, such as molecular identification based on pattern recognition techniques, cryo-ET is currently the most promising approach to comprehensively map macromolecular architecture inside cellular tomograms.

Algorithms↗
PubMed2025

Macromolecular and cytological changes in fission yeast G0 nuclei.

When starved of nitrogen, cells of the fission yeast Schizosaccharomyces pombe enter a quiescent 'G0' state with smaller nuclei and transcriptional repression. The genomics of S. pombe G0 cells has been well studied, but much of its nuclear cell biology remains unknown. Here, we use confocal microscopy, immunoblots and electron cryotomography to investigate the cytological, biochemical and ultrastructural differences between S. pombe proliferating, G1-arrested and G0 cell nuclei, with an emphasis on the histone acetylation, RNA polymerase II fates and macromolecular complex packing. Compared to proliferating cells, G0 cells have lower levels of histone acetylation, nuclear RNA polymerase II and active transcription. The G0 nucleus has similar macromolecular crowding yet fewer chromatin-associated multi-megadalton globular complexes. Induced histone hyperacetylation during nitrogen starvation results in cells that have larger nuclei and therefore chromatin that is less compact. However, these histone-hyperacetylated cells remain transcriptionally repressed with similar nuclear crowding. Canonical nucleosomes - those that resemble the crystal structure - are rare in proliferating, G1-arrested and G0 cells. Our study therefore shows that extreme changes in nucleus physiology are possible without extreme reorganization at the macromolecular level.

Schizosaccharomyces↗