584 J. T. HOLDEN 
material recoverable from normal cells by standard isolation procedures. Essentially 
normal glutamate accumulation occurs within vitamin B,-deficient cells if the in- 
cubation buffer is supplemented with acetate, ammonium ion and vitamin B, 
(Fig. 9)48. Furthermore, pretreatment of deficient cells with these substances and [12C]- 
glutamic acid results in an increased ability to accumulate [!4C|glutamic acid or 
alanine in the absence of the stimulatory substances or sucrose. A large increase in 
isolatable cell wall occurs during the pretreatment period. Although there was a 

Fig. 8(a). Electron micrographs of (a) nutritionally normal, and (b) vitamin B,-deficient cells of 
L. avabinosus. Total magnification 160 000 X 
References p. 592/594 
