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H S Forrest

Publications and source records attributed to H S Forrest.

At least 37 records · Page 2Linked to original sources
PubMed1971

Pteridines produced by Methylococcus capsulatus. Isolation and identification of a neopterin 2':3'-phosphate.

Three pteridines have been isolated from the methane- or methanol-oxidizing bacterium Methylococcus capsulatus. Two of these are known compounds, 2-amino-6-carboxy-4-hydroxypteridine and 2-amino-4-hydroxy-6-methylpteridine. The third is shown by degradative and synthetic experiments to be l-threo-neopterin 2':3'-phosphate. Labelling experiments show that both the pteridine moiety and phosphate residue are derived from a single GTP molecule. The possible metabolic significance of these compounds in methanol oxidation is discussed.

Bacteria↗
PubMed1971

Is Drosophila dAT on the Y chromosome?

DNA isolated from Drosophila melanogaster embryos contains measurable amounts of dAT, the copolymer of deoxyadenylate and deoxythymidylate. In wild-type (XX,XY) embryos, dAT constitutes 4% of the total DNA. In embryos containing extra Y chromosomes, or even extra portions of Y chromosomes, dAT constitutes as much as 7% of the total. The enrichment for dAT is dependent upon the number of extra short arms of the Y chromosome (Y(S)) or long arms (Y(L)) of the Y chromosome per individual. This enrichment of dAT dependent on the Y chromosome may be interpreted in several ways. The most straightforward interpretation is that dAT is present in high concentrations on the Y chromosome.

Adenine↗
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↗