SCHULTZ, DUMONT, AND KYTE 215 



exposed to a variety of compounds, including mercuric chloride 

 (Tingle, Paulet, and Cameron, 1973), nontobacco cigarette-smoke 

 residue (Gray and Kennedy, 1974), and phenol (Schultz and 

 Dumont, 1977). These responses undoubtedly represent generalized 

 reactions to a wide variety of adverse environmental conditions. 

 Concomitant wdth these events was the cessation of contractile 

 vacuole function; the contractile vacuole filled but ceased to 

 discharge and became severely enlarged. We interpreted this response 

 as indicative of the action of the phenolic components since pure 

 phenol (Schultz and Dumont, 1977) and the alkane-substituted 

 phenols examined in this study all elicit a similar response. 



The cytological effect of the toxicant on mitochondria is similar 

 to mitochondrial matrix changes noted in animals exposed to as Uttle 

 as 10 mg/liter of phenol (Schultz and Dumont, 1977). Unlike the 

 phenol-treated animals, however, in which the matrix density 

 returned to normal after 240 min, the matrix density of mitochon- 

 dria of Tetrahymena treated with 1% gasifier condensate did not 

 return to normal, possibly because methyl-substituted phenols, 

 which have been shown to elicit the same mitochondrial response, 

 were present in the sample. Changes in the configuration of 

 mitochondria have also been observed in media-grown exponential- 

 growth-phase Tetrahymena transferred to inorganic salts (Nilsson, 

 1970) or exposed to higher temperatures (Nilsson. 1976) or to 

 dimethyl sulfoxide (Nilsson, 1974). Hamburger and Zeuthen (1957; 

 1960) and Skriver and Nilsson (1974) reported a reduction in the 

 rate of respiration after these treatments. Schwab-Stey, Schwab, and 

 Krebs (1971) described three configurations of mitochondria isolated 

 from Tetrahymena (orthodox, intermediate, and condensed) but 

 were unable to correlate the configurational states with specific 

 energy stages or physiological conditions of the animal. The 

 orthodox configuration corresponds to the normal or control type 

 (see Fig. 3), and the condensed form is similar to mitochondria in 

 cells exposed to gasifier condensate (see Fig. 4). In our study the 

 configurational change corresponds to reduced respiratory activity, 

 but other physiological parameters that may also contribute to such 

 mitochondrial transformations are unknown at this time. 



A discussion of the significance of the effects on respiratory rates 

 of Tetrahymena cultures of longer exposure (up to 240 min) to 

 gasifier condensate must be tempered wdth the knowledge that 

 during these experiments the density of the population was reduced 

 because of cell lysis. Thus the respiratory rates correlated with the 

 number of viable cells in the culture at any given time. The 

 immediate decrease in oxygen saturation after addition of toxicant 



