Spatial and temporal variations in bacterial macromolecule labeling with (methyl-/sup 3/H)thymidine in a hypertrophic lake
The incorporation of (methyl-/sup 3/H)thymidine into three macromolecular fractions, designated as DNA, RNA, and protein, by bacteria from Hartbeespoort Dam, South Africa, was measured over 1 year by acid-base hydrolysis procedures. Samples were collected at 10 m, which was at least 5 m beneath the euphotic zone. On four occasions, samples were concurrently collected at the surface. Approximately 80% of the label was incorporated into bacterial DNA in surface samples. At 10 m, total incorporation of label into bacterial macromolecules was correlated to bacterial utilization of glucose. The labeling of DNA, which ranged between 0 and 78% of total macromolecule incorporation, was inversely related to glucose uptake, total thymidine incorporation, and euphotic zone algal production. With decreased DNA labeling, increasing proportions of label were found in the RNA fraction and proteins. Enzymatic digestion followed by chromatographic separation of macromolecule fragments indicated that DNA and proteins were labeled while RNA was not. The RNA fraction may represent labeled lipids or other macromolecules or both. The data demonstrated a close coupling between phytoplankton production and heterotrophic bacterial activity in this hypertrophic lake but also confirmed the need for the routine extraction and purification of DNA during (methyl-/sup 3/H)thymidine studies of aquatic bacterial production.
- Research Organization:
- National Institute for Water Research, Pretoria, South Africa
- OSTI ID:
- 6842329
- Journal Information:
- Appl. Environ. Microbiol.; (United States), Vol. 52:6
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
BACTERIA
PRODUCTIVITY
DNA
LABELLING
PROTEINS
RNA
THYMIDINE
UPTAKE
AQUATIC ECOSYSTEMS
LAKES
SPATIAL DISTRIBUTION
TIME DEPENDENCE
TRITIUM COMPOUNDS
AZINES
DISTRIBUTION
ECOSYSTEMS
HETEROCYCLIC COMPOUNDS
LABELLED COMPOUNDS
MICROORGANISMS
NUCLEIC ACIDS
NUCLEOSIDES
NUCLEOTIDES
ORGANIC COMPOUNDS
ORGANIC NITROGEN COMPOUNDS
PYRIMIDINES
RIBOSIDES
SURFACE WATERS
550701* - Microbiology- Tracer Techniques
550201 - Biochemistry- Tracer Techniques