Microbial degradation of dissolved proteins in seawater1

An experimental protocol using radiolabeled proteins was developed to investigate the rates and mechanisms whereby dissolved proteins are degraded in natural marine plankton communities. The results of field observations and laboratory experiments indicate that proteins are degraded by a particle-bound, thermolabile system, presumably bacteria-associated enzymes, with an apparent half-saturation constant of ca. 25 ..mu..g bovine serum albumin (BSA) per liter. Gel permeation chromatography indicated that peptides of chain length intermediate between BSA and the final products of degradation (MW<700) do not accumulate in the medium. Competition experiments indicate that the system is relatively nonspecific. Turnover rates for the protein pool in samples collected in the Southern California Bight were of the same order of magnitude as the turnover rate of the L-leucine pool and were correlated with primary productivity, chlorophyll a concentrations, bacterial abundance and biomass, and L-leucine turnover rate. These data suggest that amino acids derived from proteins are utilized preferentially and do not completely mix with the amino acids in the bulk phase.

[1]  J. Fuhrman,et al.  Thymidine incorporation as a measure of heterotrophic bacterioplankton production in marine surface waters: Evaluation and field results , 1982 .

[2]  J. Fuhrman,et al.  Cycling of organic nitrogen in marine plankton communities studied in enclosed water columns , 1980 .

[3]  D. Deibel,et al.  Aggregation of organic matter by pelagic tunicates , 1980 .

[4]  J. Trent,et al.  Marine snow: Microscale nutrient patches1 , 1979 .

[5]  G. R. Carson,et al.  Measurement of Proteolysis in Natural Waters , 1979, Applied and environmental microbiology.

[6]  M. Silver,et al.  Marine Snow: Microplankton Habitat and Source of Small-Scale Patchiness in Pelagic Populations , 1978, Science.

[7]  J. Ravel,et al.  Radiolabeling of proteins by reductive alkylation with [14C]formaldehyde and sodium cyanoborohydride. , 1978, Analytical biochemistry.

[8]  F. Azam,et al.  Size distribution and activity of marine microheterotrophs1 , 1977 .

[9]  R. Ferguson,et al.  Contribution of bacteria to standing crop of coastal plankton1 , 1976 .

[10]  Alice L. Alldredge,et al.  Discarded appendicularian houses as sources of food, surface habitats, and particulate organic matter in planktonic environments , 1976 .

[11]  B. B. North.  Primary amines in California coastal waters: Utilization by phytoplankton1 , 1975 .

[12]  Hans W. Paeri.  Bacterial uptake of dissolved organic matter in relation to detrital aggregation in marine and freshwater systems1 , 1974 .

[13]  L. Stevenson,et al.  Environmental factors associated with proteolytic activity of estuarine bacteria. , 1974, Life sciences.

[14]  F. Azam,et al.  Use of tritiated substrates in the study of heterotrophy in seawater , 1973 .

[15]  R. Rice,et al.  Radioactive labeling of proteins in vitro. , 1971, The Journal of biological chemistry.

[16]  J. Payne.  Mechanisms of bacterial peptide transport. , 1971, Ciba Foundation symposium.

[17]  J. Hobbie,et al.  RESPIRATION CORRECTIONS FOR BACTERIAL UPTAKE OF DISSOLVED ORGANIC COMPOUNDS IN NATURAL WATERS1 , 1969 .

[18]  T. Parsons,et al.  A practical handbook of seawater analysis , 1968 .

[19]  C. Lorenzen,et al.  Fluorometric Determination of Chlorophyll , 1965 .

[20]  M. L. Anson,et al.  THE ESTIMATION OF PEPSIN, TRYPSIN, PAPAIN, AND CATHEPSIN WITH HEMOGLOBIN , 1938, The Journal of general physiology.