Abstract
Mitochondria isolated from the whole body of adult Sitophilus zeamais showed high rates of oxidation of pyruvate, α-glycerophosphate and various intermediates of the tricarboxilic acid cycle. The respiratory control ratio was 3.4-8.8 with pyruvate, 2.4-3.3 with α-ketoglutalate, 2.2-2.8 with malate, 1.8-2.3 with α-glycerophosphate, 1.8-2.2 with succinate and 1.3 with ascorbate+TMPD respectively as substrate. Respiration was accompanied by phosphorylation of ADP, with the expected ADP : O ratio for all substrates tested, indicating that there are three phosphorylation sites associated with the electron transport system. The maize weevil mitophodria showed a relatively high affinity for phosphate and RCR of the mitochodria was greatly influenced by Mg++. The purity and intactness of the mitochondria in morphology was also observed by electron microscopy.
