Stephen P. Timoshenko, 1878–1972

Abstract

Few men in this century have had as great an impact on engineedng mechanics and engineering education as St~phen P. Timoshenko. Through his research and his writing he contributed remarkably to the advancement of his profession, and through his teaching and his contagious enthusiasm inspired thousands of his students and colleagues.Professor Timoshenko started his career in Russia during the turbulellt years before and d1ll'ing the Communist Revolution.

Polyamine stimulation of in vivo rates of macromolecular synthesis in a putrescine auxotroph of Aspergillus nidulans

“…The rapidity of the stimulation is consistent with the view that it is primary effects on macromolecular synthesis that are being observed. These results are similar to those obtained with a polyamine auxotroph of E. coli [3] where an immediate increase in the amount of protein was detected upon addition of putrescine to putrescine-depleted cultures while RNA and DNA did not increase for another hour. In the latter study the accumulation of radioactivity in nucleic acids and proteins was measured over an 8 h period after giving a single pulse of radioactive precursor whereas in our experiments samples were removed periodically and incubated with the radioisotope for 10 min.…”

“…It has been proposed that polyamines are involved in the synthesis of nucleic acids and proteins and/or maintaining membrane stability [ 11. Investigations of E. coli polyamine auxotrophs have demonstrated a role for polyamines in protein synthesis that is independent of transcription [2,3] . However, since both the relative amounts of the different polyamines and the control mechanisms of macromolecular synthesis in bacteria are distinct from those of eukaryotes the role of polyamines may not be comparable in both groups of organisms.…”