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Biomedical subjects

F I Maclean

Publications and source records attributed to F I Maclean.

9 recordsLinked to original sources
PubMed1987

Rectangular game theory and metabolic response to random changes in environmental states.

Rectangular game theory is applied to the response of organisms to random environmental changes: A hypothetical example of the response of a facultative algae to random changes in illumination is analyzed. Two strategies are discussed: Bayes' risk and maximin. It is shown how to detect such strategies in populations. The analysis does not require assumptions about the form of the relationship between metabolic activities and selective advantage, but assumptions about evolutionary optimization are required. The maximin strategy is shown to be related to metabolic homeostasis.

Animals↗
PubMed1966

Stimulation of photophosphorylation and cytochrome c photooxidation by pteridines.

A number of pteridines were examined for activity in promoting photophosphorylation in broken spinach chloroplasts and in stimulating cytochrome c photooxidation in sonicated chloroplasts. Correlation was found between activities for the 2 reactions. Photophosphorylation promoted by pteridines was inhibited by DCMU and by anaerobic conditions. It is concluded that pteridines may stimulate photophosphorylation by linking photosystem 1 with molecular oxygen and thereby allowing noncyclic electron flow. Aromatic pteridines in both the 2,4-dihidroxy- and 2-amino-4-hydroxy-series were active; substitution at the 6 (or 7) position was a necessary but not sufficient condition for activity in both reactions. Reducing agents increased photophosphorylation activity of aromatic pteridines and an oxidant increased activity of a tetrahydropteridine. It is postulated that pteridines are most active in their semiquinone or unstable dihydro forms.

Chloroplasts↗