Catabolism of tritiated thymidine by aquatic microbial communities and incorporation of tritium into RNA and protein

Journal Article · Tue May 01 04:00:00 EDT 1990 · Applied and Environmental Microbiology; (USA)

OSTI ID:6642985

Brittain, A M; Karl, D M ^[1]

---

1. Univ. of Hawaii, Honolulu (USA)

The incorporation of tritiated thymidine by five microbial ecosystems and the distribution of tritium into DNA, RNA, and protein were determined. Nonspecific labeling was greatest in sediment samples, for which {>=}95% of the tritium was recovered with the RNA and protein fractions. The percentage of tritium recovered in the DNA fraction ranged from 15 to 38% of the total labeled macromolecules recovered. Nonspecific labeling was independent of both incubation time and thymidine concentration over very wide ranges. We also evaluated the specificity of (2-{sup 3}H) adenine incorporation into adenylate residues in both RNA and DNA in parallel with the ({sup 3}H) thymidine experiments and compared the degree of nonspecific labeling by ({sup 3}H) adenine with that derived from ({sup 3}H)thymidine. Rapid catabolism of tritiated thymidine was evaluated by determining the disappearance of tritiated thymidine from the incubation medium and the appearance of degradation products. Degradation product formation, including that of both volatile and nonvolatile compounds, was much greater than the rate of incorporation of tritium into stable macromolecules. The standard degradation pathway for thymidine coupled with utilization of Krebs cycle intermediates for the biosynthesis of amino acids, purines, and pyrimidines readily accounts for the observed nonspecific labeling in environmental samples.

• OSTI ID: 6642985
• Journal Information: Applied and Environmental Microbiology; (USA), Journal Name: Applied and Environmental Microbiology; (USA) Vol. 56:5; ISSN 0099-2240; ISSN AEMID
• Country of Publication: United States
• Language: English

Related Subjects

550501* -- Metabolism-- Tracer Techniques
59 BASIC BIOLOGICAL SCIENCES
ADENINES
AMINES
ANTIMETABOLITES
AQUATIC ORGANISMS
AROMATICS
AZAARENES
AZINES
CATABOLISM
DNA
DRUGS
HETEROCYCLIC COMPOUNDS
HYDROGEN COMPOUNDS
ISOTOPE APPLICATIONS
METABOLISM
MICROORGANISMS
NUCLEIC ACIDS
NUCLEOSIDES
NUCLEOTIDES
ORGANIC COMPOUNDS
ORGANIC NITROGEN COMPOUNDS
PROTEINS
PURINES
PYRIMIDINES
RIBOSIDES
RNA
THYMIDINE
TRACER TECHNIQUES
TRITIUM COMPOUNDS
UPTAKE