Fragile binding

Hematological Methods. Hematological analyses can Include the determination of the total hemoglobin concentration (In g%), the packed cell volume (PCV In %), the red blood cell count (In 10 /mm ) and reticulocytes count (In %), calculation of the red cell Indices, examination of a blood film, tests to demonstrate the presence of Inclusion bodies and of sickle cells, tests to evaluate the distribution of fetal hemoglobin (Hb-F) Inside the red cells, the red cell osmotic fragility, the concentration of serum Iron (SI), total Iron binding capacity (TIBC), and the survival time of the red cells. Details of all... 

The genetic information of eukaryotic cells is propagated in the form of chromosomal DNA. Besides the nucleic acid component, chromosomes contain architectural proteins as stoichiometric components, which are involved in the protective compaction of the fragile DNA double strands. Together, the DNA and proteins form a nucleoprotein structure called chromatin. The fundamental repeating unit of chromatin is the nucleosome core particle. It consists of about 147 base pairs of DNA wrapped around a histone octamer of a (H3/H4)2 tetramer and two (H2A-H2B) heterodimers. One molecule of the linker histone HI (or H5) binds the linker DNA region between two nucleosome core particles (Bates and Thomas 1981). 

In fragile X syndrome, triplet repeat expansions are responsible for the majority of cases. It should be noted, however, that any mutation that disrupts the functional activity of the FMRl protein could lead to a similar phenotype. This was in fact established when a patient with severe fragile X syndrome was found who did not have a triplet repeat expansion. Rather, this patient had a point mutation that changed a highly conserved amino acid within the RNA-binding domain of the FMRl protein (De Boulle et al., 1993 Siomi et al., 1994 Musco et... 

Siomi, H., Choi, M., Siomi, M., Nussbaum, R., and Dreyfuss, G. (1994) Essential role for KH domains in RNA binding impaired RNA binding mutation in the KH domain of FMRl that causes fragile X syndrome. Cell 77 33-39. 

The extremely low abundance is the result of two factors, the relative fragility of the isotopes of Li, Be, and B and the high binding energy of 4He, which makes the isotopes of Li, Be, and B unstable with respect to decay/reactions that lead to 4He. For example, the nuclei 6Li, 7Li, 9Be, nB, and 10B are destroyed by stellar proton irradiations at temperatures of 2.0, 2.5, 3.5, 5.0, and 5.3 x 106 K, respectively. Thus, these nuclei cannot survive the stellar environment. (Only the rapid cooling following the Big Bang allows the survival of the products of primordial nucleosynthesis.)... 

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