Mouse anti-Human SPEG monoclonal antibody, clone 3D33D8

Escherichia coli CAG2242 cells are deficient in the speG gene encoding spermidine acetyltransferase. When these cells were cultured in the presence of 0.5 to 4 mM spermidine, their viability was greatly decreased through the inhibition of protein synthesis by overaccumulation of spermidine, When the cells were cultured with a high concentration of spermidine (4 mM), a revertant strain was obtained. We found that a 55-kDa protein, glycerol kinase, was overexpressed in the revertant and that synthesis of a ribosome modulation factor and the RNA polymerase sigma (38) subunit, factors important for cell viability, was increased in the revertant. Levels of L-glycerol 3-phosphate also increased; in the revertant. Transformation of glpFK, which encodes a glycerol diffusion facilitator (glpF) and glycerol kinase (glpK), to E, coli CAG2242 partially prevented the cell death caused by accumulation of spermidine. It was also found that L-glycerol 3-phosphate inhibited spermidine binding to ribosomes and attenuated the inhibition of protein synthesis caused by high concentrations of spermidine. These results indicate that L-glycerol 3-phosphate reduces the binding of excess amounts of spermidine to ribosomes so that protein synthesis is recovered.

We have measured the elastic scattering of a He-6 secondary beam on a C-12 target at 41.6 MeV/u. The secondary beam was produced by fragmentation with SISSI, and transported to SPEG. The combined use of SISSI and SPEG allows very good quality data to be obtained in terms of energy and angular resolution. The cross section is analysed within a 4-body (alpha + n + n + C-12) eikonal scattering model which is completely parameter-free. Very good agreement with the data is found.