Activity inhibit growth/metabolic

Bernlohr and Novelli reported that, although the mechanism of antibiotic synthesis differs from protein synthesis, there appears to be a competition between the two processes for the amino acids available in the cell. During active cellular growth with high protein synthesis, practically no bacitracin was produced. In contrast, bacitracin synthesis was high, when the requirements for protein synthesis were low, as at the end of the log phase or when protein synthesis was inhibited. The production of bacitracin, and some other antibiotics, seems to be related in some way to the sporeforming metabolism . In this phase a great part of the cell wall is dissolved, while protein production remains very low. 

Koller [31] reported that growth inhibition of wheat seedlings by all four isomers of the triazole fungicide triadimenol was not abolished by G A3, but that the effects of fungicide and GA treatments were independent. He found that the most effective isomer as a retardant was one of the most active inhibitors of sterol metabolism and concluded that this was the primary mode of action of triadimenol. In the case of the paclobutrazol enantiomers, however, there is a good correlation between KOI activity and growth retardation [4j. 

Several pesticides and other xenobiotics are metabolized in plants by mixed-function oxidases which are cytochrome P-450-dependent [28]. Inhibitors of such enzymes might therefore serve as synergists of herbicides or other crop protection compounds which are oxidatively degraded. Therefore, it has been logical to test whether the growth retardants believed to be oxygenase inhibitors would interfere with xenobiotic metabolism. Under in vitro conditions it has indeed been observed that tetcyclacis at relatively low concentrations inhibits the metabolism of the herbicide chlortoluron [10]. Similarly, the herbicidal activity of bentazon could be enhanced by tetcyclacis which, most likely, reduced its oxidative inactivation [18]. Further studies will, however, be required to find out whether such effects can be used under practical conditions. 

The typical results shown in Table 3 indicate the minimum concentrations (jLig/ml) necessary to inhibit growth of either wild-type or the recombination-deficient rec45) strain in liquid broth at 37°C. The ratio MIC (Rec )/MIC (Rec ) indicates the degree of DNA damage that was nonreparable in the repair-deficient strain in either the presence or the absence of S-9 metabolic activation. 

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