Molecular aspects of cytodifferentiation

Soluble protein and peptide pattern from different regions of rat brain during pre- and early postnatal development

Isotachophoretic pattern from phylogenetically different regions of rat brain during pre- and early postnatal development were studied. Four main observations were made: a) The patterns were greatly similar during maturation of the respective regions studied; b) One complex of peaks disappeared or decreased in quantity during the 2nd and 3rd weeks of postnatal development; c) New peaks appeared and accumulated during the same period; d) Slight differences were observable in the different regions studied.

Gene regulation in Drosophila: independent expression of closely linked, related structural loci

A number of biochemical and genetic features shared by aldehyde oxidase and pyridoxal oxidase in Drosophila melanogaster indicate a close relationship between these enzymes. The present work shows that probable structural genes for these enzymes are within about 0.08 map unit of each other. Comparison with intensively studied regions of the genome suggests that this value is of the order of magnitude expected for adjacent functional units. Despite this close linkage, there is no indication of coordinate expression of the two enzymes. These results are consistent with the idea that each structural gene is under control of its own regulatory region, but alternative explanations are possible.

Tryptophan catabolism during sporulation in Bacillus cereus

1. Two intermediates of tryptophan catabolism were isolated from a sporulating culture of Bacillus cereus and identified as anthranilic acid and kynurenine by their spectral properties. 2. During sporulation the rate of formation of anthranilic acid and kynurenine by whole cells increased and reached a maximum at the pre-spore stage. 3. The specific activities of tryptophan pyrrolase and formylase also increased during sporulation and exhibited a maximal activity at the pre-spore stage. 4. Kynureninase activity reached a maximum during early stages of sporulation and then started to decline. 5. There was a net increase in the activity of tryptophan pyrrolase when cells were grown in the presence of l-tryptophan or dl-kynurenine. 6. The cultures exhibited the maximal activity of kynureninase 2h earlier in the presence of dl-kynurenine whereas l-tryptophan delayed the appearance of the maximal activity by 2h. 7. The omission of glucose from the medium had no effect on the pattern of development of tryptophan pyrrolase during growth and sporulation. 8. On the addition of tryptophan to a chemically defined medium no significant change in the pattern of development of tryptophan pyrrolase was observed.