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SYNOPSIS. Protozoa of the order Euglenida contain a polysaccharide storage product, paramylon, composed of 1, 3-linked glucose molecules arranged into an extremely resistant granule. An enzyme was purified from the soluble phase of Euglena gracilis which would degrade this polysaccharide to single glucose residues, providing the integrity of the paramylon granule was 1st disrupted by dilute base. This enzyme, a β-1, 3 glucanase, had optimal activity at pH 5.0 and 60 C and bound tightly to base-disrupted paramylon substrate tho not to the intact granules. The specific activity of the enzyme was doubled when cell cultures reached stationary phase, the phase where net carbohydrate utilization began. An ATP-dependent hexokinase reaction was also present in Euglena homogenate. No phosphorylase activity has been found in Euglena. It is suggested, therefore, that Euglena do utilize their paramylon as a carbohydrate reserve and the mechanism of this utilization is by exo-hydrolytic cleavage to free glucose followed by phosphorylation and glycolysis.

1. 1. Conditions are discussed for obtaining population levels of 200,000/ml in 6 days using axenic cultures of the nematode, Caenorhabditis elegans. Lifespan and growth data under these conditions are presented. 2. 2. An isolation procedure which results in high quality mitochondria is presented, and metabolic data on respiaration rates, respiratory control ratios, and ADP: O ratios using various substrates are given. 3. 3. The effects of inhibitors of respiration and ATPase activity and of uncouplers of oxidative phosphorylation are presented. 4. 4. Cytochrome content of the mitochondria as determined from difference spectra is given. No indication of the large amounts of the b type pigment reported in Turbatrix aceti was found. 5. 5. The metabolism and respiratory chain of C. elegans appear to be similar to the classic mammalian systems. The only gross difference noted was the absence of ATPase stimulation by traditional uncouplers of oxidative phosphorylation. In this respect, the C. elegans mitochondria resemble more closely those of ascaris.