[3H]Leucine incorporation methodology to estimate epiphytic bacterial biomass production

1995 ◽  
Vol 29 (1) ◽  
Author(s):  
S.M. Thomaz ◽  
R.G. Wetzel
Keyword(s):  
Biomass Production ◽  
Bacterial Biomass ◽  
Leucine Incorporation

scholarly journals Biomass Production and Assimilation of Dissolved Organic Matter by SAR11 Bacteria in the Northwest Atlantic Ocean

2005 ◽  
Vol 71 (6) ◽  
pp. 2979-2986 ◽  
Author(s):  
Rex R. Malmstrom ◽  
Matthew T. Cottrell ◽  
Hila Elifantz ◽  
David L. Kirchman
Keyword(s):  
Molecular Weight ◽  
Organic Matter ◽  
Atlantic Ocean ◽  
Dissolved Organic Matter ◽  
Biomass Production ◽  
Growth Rates ◽  
Bacterial Biomass ◽  
Leucine Incorporation ◽  
Northwest Atlantic ◽  
Specific Growth Rates

ABSTRACT Members of the SAR11 clade often dominate the composition of marine microbial communities, yet their contribution to biomass production and the flux of dissolved organic matter (DOM) is unclear. In addition, little is known about the specific components of the DOM pool utilized by SAR11 bacteria. To better understand the role of SAR11 bacteria in the flux of DOM, we examined the assimilation of leucine (a measure of biomass production), as well as free amino acids, protein, and glucose, by SAR11 bacteria in the Northwest Atlantic Ocean. We found that when SAR11 bacteria were >25% of total prokaryotes, they accounted for about 30 to 50% of leucine incorporation, suggesting that SAR11 bacteria were major contributors to bacterial biomass production and the DOM flux. Specific growth rates of SAR11 bacteria either equaled or exceeded growth rates for the total prokaryotic community. In addition, SAR11 bacteria were typically responsible for a greater portion of amino acid assimilation (34 to 61%) and glucose assimilation (45 to 57%) than of protein assimilation (≤34%). These data suggest that SAR11 bacteria do not utilize various components of the DOM pool equally and may be more important to the flux of low-molecular-weight monomers than to that of high-molecular-weight polymers.

scholarly journals The Leucine Incorporation Method Estimates Bacterial Growth Equally Well in Both Oxic and Anoxic Lake Waters

2001 ◽  
Vol 67 (7) ◽  
pp. 2916-2921 ◽  
Author(s):  
David Bastviken ◽  
Lars Tranvik
Keyword(s):  
Bacterial Growth ◽  
Bacterial Biomass ◽  
Leucine Incorporation ◽  
Anoxic Conditions ◽  
Anoxic Waters ◽  
Anoxic Environments ◽  
Significant Difference ◽  
Bacterial Growth Rates ◽  
Lake Waters ◽  
Incorporation Method

ABSTRACT Bacterial biomass production is often estimated from incorporation of radioactively labeled leucine into protein, in both oxic and anoxic waters and sediments. However, the validity of the method in anoxic environments has so far not been tested. We compared the leucine incorporation of bacterial assemblages growing in oxic and anoxic waters from three lakes differing in nutrient and humic contents. The method was modified to avoid O2 contamination by performing the incubation in syringes. Isotope saturation levels in oxic and anoxic waters were determined, and leucine incorporation rates were compared to microscopically observed bacterial growth. Finally, we evaluated the effects of O2 contamination during incubation with leucine, as well as the potential effects of a headspace in the incubation vessel. Isotope saturation occurred at a leucine concentration of above about 50 nM in both oxic and anoxic waters from all three lakes. Leucine incorporation rates were linearly correlated to observed growth, and there was no significant difference between oxic and anoxic conditions. O2 contamination of anoxic water during 1-h incubations with leucine had no detectable impact on the incorporation rate, while a headspace in the incubation vessel caused leucine incorporation to increase in both anoxic and O2-contaminated samples. The results indicate that the leucine incorporation method relates equally to bacterial growth rates under oxic and anoxic conditions and that incubation should be performed without a headspace.

scholarly journals Limitation of Bacterial Growth by Dissolved Organic Matter and Iron in the Southern Ocean

2000 ◽  
Vol 66 (2) ◽  
pp. 455-466 ◽  
Author(s):  
Matthew J. Church ◽  
David A. Hutchins ◽  
Hugh W. Ducklow
Keyword(s):  
Organic Matter ◽  
Dissolved Organic Matter ◽  
Southern Ocean ◽  
Bacterial Growth ◽  
Bacterial Biomass ◽  
Biomass Accumulation ◽  
Growth Efficiency ◽  
Bacterial Growth Efficiency ◽  
Leucine Incorporation ◽  
Mean Cell Volume

ABSTRACT The importance of resource limitation in controlling bacterial growth in the high-nutrient, low-chlorophyll (HNLC) region of the Southern Ocean was experimentally determined during February and March 1998. Organic- and inorganic-nutrient enrichment experiments were performed between 42°S and 55°S along 141°E. Bacterial abundance, mean cell volume, and [3H]thymidine and [3H]leucine incorporation were measured during 4- to 5-day incubations. Bacterial biomass, production, and rates of growth all responded to organic enrichments in three of the four experiments. These results indicate that bacterial growth was constrained primarily by the availability of dissolved organic matter. Bacterial growth in the subtropical front, subantarctic zone, and subantarctic front responded most favorably to additions of dissolved free amino acids or glucose plus ammonium. Bacterial growth in these regions may be limited by input of both organic matter and reduced nitrogen. Unlike similar experimental results in other HNLC regions (subarctic and equatorial Pacific), growth stimulation of bacteria in the Southern Ocean resulted in significant biomass accumulation, apparently by stimulating bacterial growth in excess of removal processes. Bacterial growth was relatively unchanged by additions of iron alone; however, additions of glucose plus iron resulted in substantial increases in rates of bacterial growth and biomass accumulation. These results imply that bacterial growth efficiency and nitrogen utilization may be partly constrained by iron availability in the HNLC Southern Ocean.

scholarly journals Bacterioplankton abundance, biomass and production in a Brazilian coastal lagoon and in two German lakes

2001 ◽  
Vol 73 (1) ◽  
pp. 39-49 ◽  
Author(s):  
ANDRÉ L. S. FURTADO ◽  
PETER CASPER ◽  
FRANCISCO A. ESTEVES
Keyword(s):  
Bacterial Production ◽  
Bacterial Abundance ◽  
Bacterial Biomass ◽  
Isotopic Dilution ◽  
Leucine Incorporation ◽  
Temperate Lakes ◽  
Tropical Lagoon ◽  
Organic Carbon Concentration ◽  
Micro Organisms ◽  
Bacterioplankton Abundance

The bacterioplanktonic abundance, biomass, and production within a tropical lagoon (Cabiúnas, Brazil) and two temperate lakes (Stechlin and Dagow, Germany) were compared. Bacterial abundance and production were significantly different among the three water bodies. The lowest bacterial production ( 0.8mug C l-1 d-1) was observed in the tropical Cabiúnas Lagoon despite its higher mean temperature and dissolved organic carbon concentration. Highest bacterioplankton abundance ( 2.6 x 10(9) cells l-1) and production ( 68.5mug C l-1 d-1) were measured in eutrophic Lake Dagow. In oligotrophic Lake Stechlin, the lowest bacterial biomass ( 48.05mug C l-1) was observed because of lower bacterial biovolume ( 0.248mum³) and lower bacterial abundance. Bacterial populations in the temperate lakes show higher activity (production/biomass ratio) than in the tropical lagoon. The meaning of isotopic dilution and leucine incorporation by non-bacterial micro-organisms were evaluated in the oligotrophic temperate system. Leucine uptake by non-bacterial micro-organisms did not have significant influence on bacterial production.

Bacterial population dynamics, production, and heterotrophic activity in a recently formed reservoir

1999 ◽  
Vol 45 (9) ◽  
pp. 747-753 ◽  
Author(s):  
Louis B Jugnia ◽  
Rémy D Tadonléké ◽  
T Sime-Ngando ◽  
J Devaux ◽  
C Andrivon
Keyword(s):  
Primary Production ◽  
Chlorophyll A ◽  
Biomass Production ◽  
Resource Availability ◽  
Bacterial Production ◽  
Standing Stock ◽  
Bacterial Biomass ◽  
Heterotrophic Activity ◽  
Chlorophyll A Concentration ◽  
Biological Variables

Seasonal and spatial fluctuations in abundance, biomass production, and potential heterotrophic activity (i.e., 14C-glucose uptake) of bacterioplankton assemblages in a 1-year-old reservoir (the Sep Reservoir, Puy-de-Dôme, France) were examined concurrently with water temperature, phytoplankton chlorophyll a concentration, and primary production (PP). Based on the values observed for these biological variables, the Sep Reservoir was considered to have evolved to an oligo-mesotrophic state. Spatiotemporal variations of bacterial variables were a consequence of the seasonal evolution of the reservoir coupled with the resource availability. Multivariate regression analyses suggest that about 14 and 26% of the variance in bacterial standing stock and activity may be explained by the physical environment (i.e., temperature) and a resource availability index (chlorophyll a concentration or primary production), respectively. A carbon budget indicated that 4-126% (mean = 20%) of the ambient PP may be channeled through the microbial loop via bacterial biomass production. Heterotrophic bacterial production in the Sep Reservoir may therefore, on occasion, represent a significant source of carbon for higher order consumers.Key words: reservoirs, plankton, bacteria, heterotrophic uptake, primary and bacterial production.

Sign in / Sign up

Export Citation Format

Share Document