Using the Nucleus as a Source of Energy

To get the nuclei to react, the bombarding nucleus must have enough kinetic euCTgy to overcome the repulsion of electric charges of the nuclei. The first reaction uses only deuterium, which is present in ordinary water. It is therefore very attractive as a source of energy. But, as we will discuss, the second reaction is more likely to be used first. 

In nuclear fission, neutron bombardment causes a nucleus to split, releasing neutrons that split other nuclei to produce a chain reaction. A nuclear power plant controls the rate of the chain reaction to produce heat that creates steam, which is used to generate eiectricity. Potential hazards, such as radiation leaks, thermal pollution, and disposal of nuclear waste, remain current concerns. Nuclear fusion holds great promise as a source of clean abundant energy, but it requires extremely high temperatures and is not yet practical. 

For X-ray generation, other radionucleides such as 241 Am (r = 430 years) can be used. This nucleus emits a radiation accompanied by b photons of 60 keV energy. Finally, it is possible to mix a / -emitter and a second element, which is used as a target and plays the role of the anticathode in an X-ray tube. For example, the source 147Pm/Al (r — 2.6 years) emits a decelerating radiation between 10 and 200 keV. 

Anti-deoxyribonucleic acid autoantibodies from human and mice suffering from Lupus erythematosus can penetrate into cells and accumulate in the cell nucleus. Based on the characteristics of a mi-ON A autoantibodies, VAYISRGGVSTYYSDTVKGRFTRQKYNKRA peptide (P3), which exhibits a-helix, has been used as a vector for the intracytoplasmic and intranuclear translocation of macromolecules (Table 16.7) (Avrameas et al., 1998, 1999). P3 shares similar capabilities with Antenapedia peptide (Derossi et al., 1994), but in contrast P3 operates only at 37 °C by an energy dependent mechanism. P3 linked to a 19 lysine residue sequence (K19-P3) forms complexes with plasmid DNA. Efficient transfection of mouse 3T3 cells and hamster lung CCL39 cells were obtained with these complexes. This transfection was not impaired by the presence of serum and did not require helper molecules such as chloroquine. These observations suggest that peptides from cell specific anti-DNA autoantibodies may represent a source of peptide-based gene delivery system with different specificities. 

---