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.

Download Full-text

Myoinositol biosynthesis by Sertoli cells, and levels of myoinositol biosynthetic enzymes in testis and epididymis

Canadian Journal of Biochemistry ◽

10.1139/o79-117 ◽

1979 ◽

Vol 57 (6) ◽

pp. 962-967 ◽

Cited By ~ 32

Author(s):

Ranga Robinson ◽

Irving B. Fritz

Keyword(s):

Sertoli Cells ◽

Specific Activity ◽

Primary Cultures ◽

Defined Medium ◽

Seminiferous Tubules ◽

Chemically Defined Medium ◽

Dibutyryl Cyclic Amp ◽

Old Rats ◽

Specific Activities ◽

Germinal Cells

Levels of glucose-6-phosphate cyclase (myoinositol-1-phosphate synthase, EC 5.5.1.4) and myoinositol-1-phosphate phosphatase (myoinositol-1-phosphatase, EC 3.1.3.25) were determined in extracts of testes from 10-, 20-, and 30-day-old rats, and in extracts of Sertoli cells, germinal cells, and epididymides. The specific activity of the cyclase was approximately [Formula: see text] that of the phosphatase in all extracts found to contain either enzyme. Among cells in the testis examined, Sertoli cells had highest levels of enzymes required for inositol biosynthesis from glucose, while spermatocytes and round spermatids did not have detectable activity. Spermatozoa from the epididymis also had no detectable cyclase or phosphatase activity. In contrast, extracts of washed epididymides contained exceedingly high specific activities of these enzymes. Primary cultures of Sertoli cells, maintained in a chemically defined medium without added inositol, released inositol into the medium during three successive 24-h periods. The amounts released were greater in cells stimulated by dibutyryl cyclic AMP. Results were interpreted to indicate that inositol in the fluid of seminiferous tubules most probably originates from Sertoli cells, which synthesize inositol from glucose. Additional inositol in the fluid of epididymal tubules could readily be provided by metabolism of glucose by epididymal epithelial cells.

Download Full-text