Search results for "Nucleoid"
showing 4 items of 4 documents
Detection of DNA damage in stimulated human lymphocytes after enflurane exposure in vitro
1992
DNA damage was detected by nucleoid sedimentation in human lymphocytes stimulated with pokeweed mitogen after exposure to enflurane. Enflurane induces DNA damage at an exposure concentration of 0.2 vol%. Higher enflurane concentrations increase the rate of DNA damage. The DNA damage seen after exposure to enflurane concentrations of 0.2 and 3.0% vol is comparable to damage after X-radiation of 0.1 and 0.7 Gy. DNA single-strand breaks can be demonstrated by nucleoid sedimentation and can indicate damage before DNA repair begins. Therefore, detected DNA single-strand breaks may be reversible. However, DNA repair is not always successful and an increased number of DNA single-strand breaks coul…
Damage in Escherichia coli Cells Treated with a Combination of High Hydrostatic Pressure and Subzero Temperature
2007
ABSTRACT The relationship between membrane permeability, changes in ultrastructure, and inactivation in Escherichia coli strain K-12TG1 cells subjected to high hydrostatic pressure treatment at room and subzero temperatures was studied. Propidium iodide staining performed before and after pressure treatment made it possible to distinguish between reversible and irreversible pressure-mediated cell membrane permeabilization. Changes in cell ultrastructure were studied using transmission electron microscopy (TEM), which showed noticeable condensation of nucleoids and aggregation of cytosolic proteins in cells fixed after decompression. A novel technique used to mix fixation reagents with the c…
ORGANIZATION OF HIGHER-LEVEL CHROMATIN STRUCTURES (CHROMOMERE, CHROMONEMA AND CHROMATIN BLOCK) EXAMINED USING VISIBLE LIGHT-INDUCED CHROMATIN PHOTO-S…
2002
The method of chromatin photo-stabilization by the action of visible light in the presence of ethidium bromide was used for investigation of higher-level chromatin structures in isolated nuclei. As a model we used rat hepatocyte nuclei isolated in buffers which stabilized or destabilized nuclear matrix. Several higher-level chromatin structures were visualized: 100 nm globules—chromomeres, chains of chromomeres—chromonemata, aggregates of chromomeres—blocks of condensed chromatin. All these structures were completely destroyed by 2 M NaCl extraction independent of the matrix state, and DNA was extruded from the residual nuclei (nuclear matrices) into a halo. These results show that nuclear …
Mitochondrial DNA Replication in Health and Disease
2011
Mitochondria are dynamic, semi-autonomous organelles that play a diverse role in cellular physiopathology, being involved in bioenergetics, ROS generation/signaling and redox balance, β-oxidation of free fatty acids, Ca2+ homeostasis, thermogenesis, and essential anabolic pathways (fatty acids, cholesterol, urea, haem and bile acids). They contain their own, mitochondrial DNA (mtDNA) which is one of the main points in favor of the hypothesis of the endosymbiotic origin of these organelles (Lang et al., 1999). The human mitochondrial genome, a 16.5 kb circular DNA consisting of a heavy and a light chain, contains 37 genes, 13 of which encode proteins involved in the mitochondrial electron tr…