Biological growth inhibition

S. Alstrom and R. G. Burns, Cyanide production by rhizobacteria as a possible mechanism of plant growth inhibition. Biology and Fertility of Soils 7 232 (1989). 

Table 7.3 shows the concentrations of 1-5 that result in 50% growth inhibition (GI50) of five human cancer cell lines. Inspection of these data reveals that cytostatic activity of 1 and 3-5 depends on the thermodynamic favorability of the quinone methide species compared to the corresponding keto form. The most cytostatic prekinamycins 1 and 5 are associated with the thermodynamically stable quinone methides. In contrast, the inactive prekinamycins 3 and 4 are associated with thermodynamically stable keto tautomers. The exception is prekinamycin 2, which is cytostatic and possesses a relatively stable keto tautomer 3 compared to its quinone methide. Although the AE value for quinone methide tautomerization can predict cytostatic properties, prekinamycin 2 shows that there must be other factors determining biological activity. 

Chemicals are added to the circulation system to prevent fouling. Dispersants are added to prevent deposit of solids, corrosion inhibitors to prevent corrosion and biocides to inhibit biological growth. 

Concern for the continued widespread use of chlordane centers on its ability to cause liver cancer in domestic mice. Other adverse effects in mammals, such as elevated tissue residues and growth inhibition, were frequently associated with diets containing between 0.76 and 5.0 mg chlordane/kg feed. Metabolism of technical chlordane by mammals results primarily in oxychlordane, a metabolite that is about 20 times more toxic than the parent compound and the most persistent metabolite stored in adipose tissues. Chlordane interactions with other agricultural chemicals produced significant biological effects in warm-blooded organisms, indicating a need for additional research on this subject. 

To determine the toxicity of a compound for a biological system, an observable and well-defined end effect must be identified. Turbidity or acid production, reflecting the growth or growth inhibition of a culture, may be used as an endpoint in bacterial... 

L-Canaline shares with canavanine an appreciable potential for eliciting adverse biological effects. Evaluations with].. minor of some 55 naturally occurring and synthetic amino acids indicated that canavanine and canaline were amongst the most toxic canaline exhibited slightly greater growth-inhibition than canavanine ( ). These toxic non-protein amino acids interact to curtail additively the proliferation of this aquatic plant (24). 

Environment Canada (1992b) Biological test method growth inhibition test using the freshwater alga Selenastrum capricornutum, Environmental Protection Publications, Environment Canada, Ottawa, EPS Report l/RM/25, 41 pp. 

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