Apoptosis Chromatin condensation

Another morphological assay of apoptosis is done with acridine orange, a nuclear staining that reveals chromatin condensation under light and fluorescent microscope. 

H3-H4 Chaperone activity during rapid replication in early embryogenesis Sperm decondensation Chromatin condensation during apoptosis... 

Histone H2B amino-terminal tail is essential for chromatin condensation (de la Barre et al, 2001). In Xenopus, chicken, and human cells phosphorylation of H2B at Serine 14 by Mstl (Mammalian Sterile Twenty) kinase has been finked to chromatin compaction during apoptosis (Ajiro, 2000 Cheung et al, 2003), and DNA double-strand breaks (Fernandez-Capetillo et al, 2004) (Fig. 2) (Table 1). At late time points after irradiation, phosphorylated H2B (S14) accumulates into... 

Thermal and chemical cellular stresses result in the rapid disappearance of ubiquitinated histones [258,259]. The levels of ubiquitinated histones drops precipitously after human tumor cells are treated with proteasome inhibitors [260,261]. Deubiquitination of uH2A also occurs during apoptosis, with its lose coinciding with nuclear pyknosis and chromatin condensation [262,263]. 

Further study demonstrated that THS significantly inhibited hepatic DNA fragmentation, the emergence of apoptotic bodies and chromatin condensation in D-GalN/LPS-induced liver injury in mice. The extent of the inhibitory effect of THS on hepatocyte apoptosis at 5 hr paralleled that on serum ALT elevation at 8 hr [87]. As mentioned above, in this model, a large number of hepatocytes undergoing apoptotic cell death can... 

On the other hand, there is strong evidence that the effects of flavonoids on cultured cells are not merely toxic but via induction of apoptosis or inhibition of proliferation. Thus signs of apoptosis, such as induction of caspase-3, fragmentation of DNA and chromatin condensation, are frequently detected upon cell exposure to flavonoids [213, 217-221]. In addition, the effects of flavonoids are generally reversible upon removal or addition of serum [222-224]. 

Currently, there are many methods available for determining cell death by apoptosis in cell cultures and tissues. These methods are based essentially on changes that occur in apoptotic cells. During apoptosis, several phenomena can be observed, such as DNA fragmentation, chromatin condensation, nuclear fragmentation, cytoplasm acidification, cytochrome c release from the mitochondria, exposure of intracellular phospholipids and the activation and breakdown of proteins. These apoptotic phenomena can be detected by direct or indirect methods, on cell populations or on individual cells that are representative of a population. The main principles used by the different detection methods are ... 

Several methods are based on microscopy observations to detect morphological changes in the cells, mainly chromatin condensation. Different markers can be used to differentiate between the stages of apoptosis. 

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