we have found that when a buffer utilized for in vitro polymerization of microtubules , i.e. , 1 mm guanosine triphosphate , 1 mm mgso4 , 2 mm ethylene glycol bis ( beta-aminoethyl ether ) -n , n'-tetraacetic acid 100 mm piperazine-n , n'-bis ( 2-ethanesulfonic acid ) , ph 6.9 polymerization mix , was used in the glutaraldehyde prefixation regimen instead of classical fixative buffers , i.e. , isotonic cacodylate or phosphate buffer , the following features were observed in thin-sections of the cytoplasm of interphase hela cells : ( a ) a greater than 2-fold increase in total microtubule contour length , ( b ) a 2-fold increase in a number of microtubules greater than or equal to 1 mu long , ( c ) an enhanced association of microtubules with cytoplasmic organelles , and ( d ) an increased clustering of 100 a filaments located in a perinuclear region of the cell .
C0010834
cytoplasm
C1179962
cytoplasmic organelles