The In Vivo Distribution of Bacterial Polysomes, Ribosomes, and Ribosomal Subunits

Effects of tris and oligoamines on the ribosomal size distribution in lysates of B. licheniformis

“…The cationic composition of the intracellular fluid of exponential-phase bacteria appears to be about 60 mM K +, 10 mM Mg 2÷ and 1 to 2 mM of oligoamines [4,[11][12][13][14][15]. Other cations are usually present in much lower concentrations.…”

“…The size distribution of ribosomes in bacterial lysates depends on the cationic composition of the lysis buffer [1][2][3][4]. Little or no 70 S particles are present when lysis is carried out in 5 mM tris-buffer containing 40 to 60 mM Na + [3][4][5][6] or a low concentration of Mg 2÷ ions [1,2].…”

“…Little or no 70 S particles are present when lysis is carried out in 5 mM tris-buffer containing 40 to 60 mM Na + [3][4][5][6] or a low concentration of Mg 2÷ ions [1,2]. In other cases a prominent peak of 70 S particles is observed in the sedimentation pattern [7][8][9][10][11].…”

Occurrence of termination ribosomes as free 70 S particles

“…Moreover Varricchio has found 4-7 percent of the total ribosomes as initiation monosomes. He and other workers [9,5,6] have suggested that the ribosome profile obtained in Na'-containing gradients was a good picture of the in uivo distribution and that during the ribosome cycle the subunits were released from polyribosomes at the end of each round of translation.…”

“…These results, based on the ribosome profiles obtained after sucrose gradient centrifugations, vary according to the culture medium [l] , the lysis conditions [2][3][4][5][6][7] and the ionic composition of the sucrose solutions employed.…”