scholarly journals Elemental Composition, Phosphorous Uptake, and Characteristics of Growth of a SAR11 Strain in Batch and Continuous Culture

mSystems ◽  
2019 ◽  
Vol 4 (4) ◽  
Author(s):  
Scott R. Grant ◽  
Matthew J. Church ◽  
Sara Ferrón ◽  
Edward A. Laws ◽  
Michael S. Rappé
Keyword(s):  
Continuous Culture ◽  
Bacterial Production ◽  
P Uptake ◽  
Cellular Growth ◽  
Leucine Incorporation ◽  
Natural Seawater ◽  
Organic C ◽  
The Mean ◽  
Ocean Ecosystem ◽  
Specific Growth Rates

ABSTRACTIn this study, a strain of SAR11 subgroup IIIa (termed HIMB114) was grown in seawater-based batch and continuous culture in order to quantify cellular features and metabolism relevant to SAR11 ecology. We report some of the first direct measurements of cellular elemental quotas for nitrogen (N) and phosphorus (P) for SAR11, grown in batch culture: 1.4 ± 0.9 fg N and 0.44 ± 0.01 fg P, respectively, that were consistent with the small size of HIMB114 cells (average volume of 0.09 μm3). However, the mean carbon (C) cellular quota of 50 ± 47 fg C was anomalously high, but variable. The rates of phosphate (PO43−) uptake measured from both batch and continuous cultures were exceptionally slow: in chemostats growing at 0.3 day−1, HIMB114 took up 1.1 ± 0.3 amol P cell−1day−1, suggesting that <30% of the cellular P requirement of HIMB114 was met by PO43−assimilation. The mean rate of leucine incorporation, a measure of bacterial production, during late-log-phase growth of batch HIMB114 cultures was 0.042 ± 0.02 amol Leu cell−1h−1. While only weakly correlated with changes in specific growth rates, the onset of stationary phase resulted in decreases in cell-specific leucine incorporation that were proportional to changes in growth rate. The rates of cellular production, respiratory oxygen consumption, and changes in total organic C concentrations constrained cellular growth efficiencies to 13% ± 4%. Hence, despite a small genome and diminutively sized cells, SAR11 strain HIMB114 appears to grow at efficiencies similar to those of naturally occurring bacterioplankton communities.IMPORTANCEWhile SAR11 bacteria contribute a significant fraction to the total picoplankton biomass in the ocean and likely are major players in organic C and nutrient cycling, the cellular characteristics and metabolic features of most lineages have either only been hypothesized from genomes or otherwise not measured in controlled laboratory experimentation. The dearth of data on even the most basic characteristics for what is arguably the most abundant heterotroph in seawater has limited the specific consideration of SAR11 in ocean ecosystem modeling efforts. In this study, we provide measures of cellular P, N, and C, aerobic respiration, and bacterial production for a SAR11 strain growing in natural seawater medium that can be used to directly relate these features of SAR11 to biogeochemical cycling in the oceans. Through the development of a chemostat system to measure nutrient uptake during steady-state growth, we have also documented inorganic P uptake rates that allude to the importance of organic phosphorous to meet cellular P demands, even in the presence of nonlimiting PO43−concentrations.

scholarly journals Characteristics of a SAR11 strain grown in batch and continuous culture

2018 ◽  
Author(s):  
Scott R. Grant ◽  
Matthew J. Church ◽  
Sara Ferrón ◽  
Edward A. Laws ◽  
Michael S. Rappé
Keyword(s):  
Continuous Culture ◽  
Bacterial Production ◽  
P Uptake ◽  
Cellular Growth ◽  
Leucine Incorporation ◽  
Natural Seawater ◽  
Organic C ◽  
The Mean ◽  
Ocean Ecosystem ◽  
Specific Growth Rates

AbstractIn this study, a strain of SAR11 subgroup IIIa (termed HIMB114) isolated from the tropical Pacific Ocean was grown in seawater-based batch and continuous culture in order to quantify cellular features and metabolism relevant to SAR11 ecology. We report the first direct measurements of cellular elemental quotas for nitrogen (N) and phosphorus (P) for SAR11: 1.4 ± 0.9 fg N and 0.44 ± 0.01 fg P, respectively, that were consistent with the small size of HIMB114 cells (average volume of 0.09 µm3). However, the mean carbon (C) cellular quota of 50 ± 47 fg C was anomalously high, but variable. Rates of phosphate (PO43-) uptake measured from both batch and continuous cultures were exceptionally slow: in chemostats growing at 0.3 d−1, HIMB114 took up 1.1 ± 0.3 amol P cell−1d−1, suggesting that <30% of the cellular P requirement of HIMB114 was met by PO43-assimilation. The mean rate of leucine incorporation, a measure of bacterial production, during late log phase growth of batch HIMB114 cultures was 0.042 ± 0.02 amol Leu cell−1h−1. While only weakly correlated with changes in specific growth rates, the onset of stationary phase resulted in decreases in cell-specific leucine incorporation that were proportional to changes in growth rate. Rates of cellular production, respiratory oxygen consumption, and changes in total organic C concentrations constrained cellular growth efficiencies to 13 ± 4%. Hence, despite the small, streamlined genome and diminutively sized cells, SAR11 strain HIMB114 appears to grow at efficiencies similar to naturally occurring bacterioplankton communities.ImportanceWhile SAR11 bacteria contribute a significant fraction to the total picoplankton biomass in the ocean and likely are major players in organic C and nutrient cycling, the cellular characteristics and metabolic features of most lineages have either been only hypothesized from genomes or otherwise not measured in controlled laboratory experimentation. The dearth of data on even the most basic characteristics for what is arguably the most abundant heterotroph in seawater has limited the specific consideration of SAR11 in ocean ecosystem modeling efforts. In this study, we provide measures of cellular P, N, C, aerobic respiration and bacterial production for a SAR11 strain growing in natural seawater media that can be used to directly relate these features of SAR11 to biogeochemical cycling in the oceans. Through the development of a chemostat system to measure nutrient uptake during steady-state growth, we have also documented inorganic P uptake rates that allude to the importance of organic phosphorous to meet cellular P demands, even in the presence of non-limiting PO43-concentrations.

Column experiments show that cycling of both nitrogen and phosphorus is altered by dissolved organic carbon in river sediments

2021 ◽  
Author(s):  
Marc Stutter ◽  
Daniel Graeber ◽  
Gabriele Weigelhofer
Keyword(s):  
Organic Carbon ◽  
Nutrient Uptake ◽  
Inorganic Nitrogen ◽  
River Sediments ◽  
P Uptake ◽  
Controlled Study ◽  
Column Experiments ◽  
Nitrogen And Phosphorus ◽  
Organic C ◽  
Riparian Trees

&lt;p&gt;Since agriculture and wider development have altered simultaneously runoff, pollution and natural structures in catchments (e.g. wetlands, floodplains, soil drainage, riparian trees) aquatic ecosystems deviate from background concentrations of N and P, but also organic C (OC). Hence mechanistic studies coupling OC, N and P are needed and whilst data coupling OC:N is becoming more available and interpreted this is not yet the case for aquatic OC:P.&amp;#160; Column flow experiments (excluding light) allow preliminary controlled study of microbial biogeochemical processes in benthic sediments exposed to factorial nutrients (here +C, +NP, +CNP using simple dissolved substrates glucose, nitrate, and phosphate).&lt;/p&gt;&lt;p&gt;Based on the stoichiometric theory, we tested the hypothesis that bioavailable DOC will stimulate the heterotrophic uptake of soluble reactive P (SRP) and dissolved inorganic nitrogen in stream sediments. Glucose-C additions increased nutrient uptake, but also NP additions enhanced consumption of native and added OC. The effects of C addition were stronger on N than P uptake, presumably because labile C stimulated both assimilation and denitrification, while adsorption (unaffected by the presence or not of OC) formed a part of P uptake. Internal biogeochemical cycling lessened net nutrient uptake due to N and P recycling into dissolved organically-complexed forms (DOP and DON).&lt;/p&gt;&lt;p&gt;Simple column experiments point to mechanisms whereby availability of organic carbon can stimulate N and P sequestration in the bed of nutrient-polluted streams. This should promote further studies coupling OC with N and, especially P, towards better knowledge and ability to incorporate coupled macronutrient cycles into nutrient models and, potentially, ecosystem management.&lt;/p&gt;

Stratification of soil organic C, N and the C:N ratio as affected by different plastic film mulching modes in a semiarid region of China

Soil Research ◽  
2019 ◽  
Vol 57 (4) ◽  
pp. 408 ◽  
Author(s):  
Peng Zhang ◽  
Ting Wei ◽  
Zhikuan Jia ◽  
Xiaolong Ren
Keyword(s):  
Crop Yields ◽  
C:N Ratio ◽  
Semiarid Region ◽  
Plastic Film ◽  
Organic C ◽  
Soil C ◽  
North West ◽  
Plastic Film Mulching ◽  
Film Mulching ◽  
The Mean

The soil degradation caused by plastic film mulching tillage in rain-fed areas of north-west China is known to affect sustainable and stable crop yields because of major losses of soil organic carbon (SOC) and nutrients. To evaluate the effects of different plastic film mulching modes on SOC and total nitrogen (STN) sequestration capacity in loessic soil, we investigated the effects of different plastic film mulching on SOC, STN, and the soil C:N ratio in semiarid areas of southern Ningxia for a 4-year period (2013–2016). Five treatments were tested: (i) the control, conventional flat planting without mulching (CK); (ii) alternating mulching and bare rows without ridges and planting in mulched rows (P); (iii) furrow planting of maize, separated by consecutive plastic film-mulched ridges (S); (iv) furrow planting of maize, separated by alternating large and small plastic film-mulched ridges (D); and (v) furrow-flat planting of maize with a large plastic film-mulched ridge alternating with a flat plastic film-mulched space (R). In the final experimental year (2016), the results showed that the mean soil bulk density at 0–60 cm depth had decreased with film mulching treatments by 2.82%, 5.90% (P &lt; 0.05), 7.29% (P &lt; 0.05), and 9.46% (P &lt; 0.05) respectively, compared with CK. Film mulching increased the concentration of SOC and STN, which were ranked in order S &gt; R/D &gt; P &gt; CK; however, there was no significant increase with the storage of SOC and STN. The mean soil C:N ratio was higher with mulching treatment, i.e. 2.91% (P &gt; 0.05) higher than CK in 0–60 cm depth. Mulching treatments significantly (P &lt; 0.05) increased the stratification ratio (SR) of SOC and soil C: N ratio from the surface (0–20 cm) to all depths compared with CK, i.e. the SR of SOC at the 0–20:20–40 cm depth significantly (P &lt; 0.05) increased with D, R, S, and P by 14.81%, 9.47%, 14.18%, and 9.51% respectively, compared with CK.

Corrigenda - Application of a simple-model to assess the ground-water contamination potential of pesticides

Soil Research ◽  
1995 ◽  
Vol 33 (6) ◽  
pp. 1031
Author(s):  
HJ Di ◽  
RS Kookana ◽  
LAG Aylmore
Keyword(s):  
Simple Model ◽  
Ground Water ◽  
Water Contamination ◽  
Preferential Flow ◽  
Field Capacity ◽  
Ground Water Contamination ◽  
Organic C ◽  
Number Of Layers ◽  
Structured Soils ◽  
The Mean

A simple model is described for assessing the ground water contamination potential of pesticides. This model, based on simple processes of linear, equilibrium and singular partition between solution and soil organic matter, steady convective flow, and first-order degradation, calculates fractions of pesticides remaining in the soil as they leach to greater depth. Possible effects by preferential flow that may be present in structured soils are ignored. The soil profile is divided into a number of layers which may differ in bulk density, moisture content at field capacity, organic C content, and degradation half-life. The leaching depths predicted by this model generally agreed with the mean leaching depths measured in a field study, and with those predicted by the CALF model. The leaching depths by the simple model were also statistically related to those simulated by the LEACHM model, although the values by LEACHM were found to be much higher than those by the simple model and by CALF. Under the soil and environmental conditions given, the simple model predicted that chlorpyriphos and chlorthal dimethyl would not leach to any noticeable depth before being completely degraded, that metribuzin, prometryne, propyzamide and simazine would mostly degrade to insignificant concentrations before reaching 500 cm, and that traces of fenamiphos, metalaxyl and linuron might reach beyond 1000 cm.

scholarly journals Heterotrophic bacterial production in the South East Pacific: longitudinal trends and coupling with primary production

2007 ◽  
Vol 4 (4) ◽  
pp. 2761-2791 ◽  
Author(s):  
F. Van Wambeke ◽  
I. Obernosterer ◽  
T. Moutin ◽  
S. Duhamel ◽  
O. Ulloa ◽  
...  
Keyword(s):  
Pacific Ocean ◽  
Primary Production ◽  
Bacterial Production ◽  
South Pacific ◽  
Leucine Incorporation ◽  
The South ◽  
Phytoplankton Primary Production ◽  
East Pacific ◽  
Wide Range ◽  
South Pacific Gyre

Abstract. Spatial variations of heterotrophic bacterial production and phytoplankton primary production were investigated across South East Pacific Ocean (–141° W, –8° S to –72° W, –35° S) in November–December 2004. Bacterial production (³H leucine incorporation) integrated over the euphotic zone encompassed a wide range of values, from 43 mg C m−2 d−1 in the hyper-oligotrophic South Pacific Gyre to 392 mg C m−2 d−1 in the upwelling off Chile. Within the gyre (120° W, 22° S) records of low phytoplankton biomass (7 mg TChla m−2) were obtained and in situ 14C based particulate primary production rates were as low as 153 mg C m−2 d−1, thus equal to the value considered as a limit for primary production under strong oligotrophic conditions. In the South Pacific gyre average rates of ³H leucine incorporation rates, and leucine incorporation rates per cell (5–21 pmol L−1 h−1 and 15–56×10−21 mol cell−1 h−1, respectively), were in the same range as those reported for other oligotrophic sub tropical and temperate waters. Rates of dark community respiration, determined at selected stations across the transect varied in a narrow range (42–97 mmol O2 m−2 d−1), except for one station in the upwelling off Chile (245 mmol O2 m−2 d−1). Bacterial growth efficiencies varied between 5 and 38% and bacterial carbon demand largely exceeded 14C particulate primary production across the South Pacific Ocean. Net community production also revealed negative values in the South Pacific Gyre (–13±20 to –37±40 mmol O2 m−2 d−1). Such imbalances being impossible in this area far from any external input, we discuss the techniques involved for determining the coupling between primary production and bacterial heterotrophic production.

CONTINUOUS CULTURE STUDIES ON FOUR SPECIES OF FIBROLYTIC RUMEN BACTERIA WITH PURE CELLULOSE AS SUBSTRATE

1984 ◽  
Vol 64 (5) ◽  
pp. 49-49
Author(s):  
A. KISTNER ◽  
J. H. KORNELIUS ◽  
G. S. MILLER
Keyword(s):  
Continuous Culture ◽  
Growth Rates ◽  
Buffer Capacity ◽  
Specific Growth ◽  
Ph Value ◽  
Culture Studies ◽  
Pure Cellulose ◽  
Constant Ph ◽  
Continuous Culture System ◽  
Specific Growth Rates

The specific growth rates of one strain each of Ruminoccoccus flavefaciens, R. albus, Bacteroides succinogenes and Clostridium polysaccharolyticum were measured at a constant pH value in a pH-auxostat continuous culture system, using ball-milled filter paper cellulose as limiting substrate. By manipulating the buffer capacity of the medium, the degree to which the substrate was utilized before fresh medium was dosed to the cultures was controlled. With all four species, the specific growth rates declines as the cultures were forced to utilize the more refractory (crystalline?) portion of the substrate, but the species differed in the steepness of this decline. (Graphs of specific growth rates versus degree of solubilization of cellulose will be presented.) These dissimilarities in behavior are probably a reflection of differences between the species in the complements of cellulases at their disposal. Key words: Continuous culture, cellulases, bacteria, cellulose

scholarly journals Abundant proteins contribute strongly to noise in the growth rate of optimally growing bacteria

2020 ◽  
Author(s):  
L.H.J. Krah ◽  
R. Hermsen
Keyword(s):  
Growth Rate ◽  
Low Noise ◽  
Cellular Growth ◽  
Bacterial Cells ◽  
Noise Levels ◽  
Physiological Variables ◽  
Stochastic Fluctuations ◽  
Two Factors ◽  
The Mean ◽  
Related Proteins

AbstractIn bacterial cells, protein expression is a highly stochastic process. At the same time, physiological variables such as the cellular growth rate also fluctuate significantly. A common intuition is that, due to their relatively high noise amplitudes, proteins with a low mean expression level are the most important causes of these fluctuations on a larger, physiological scale. Noise in highly expressed proteins, whose stochastic fluctuations are relatively small, is often ignored. In this work, we challenge this intuition by developing a theory that predicts the contribution of a protein’s expression noise to the noise in the instantaneous, cellular growth rate. Using mathematical analysis, we decomposed the contribution of each protein into two factors: the noise amplitude of the protein, and the sensitivity of the growth rate to fluctuations in that protein’s concentration. Next, we incorporated evolution, which has shaped the mean abundances of growth-related proteins to optimise the growth rate, causing protein abundances, but also cellular sensitivities to be non-random. We show that in cells that grow optimally fast, the growth rate is most sensitive to fluctuations in highly abundant proteins. This causes such proteins to overall contribute strongly to the noise in the growth-rate, despite their low noise levels. The results are confirmed in a stochastic toy model of cellular growth.

scholarly journals Effect of Phosphorous Application on Yield and its Uptake by Soybean (Glycine max L.) in Different Cropping Systems

2021 ◽  
Author(s):  
R. Sikka ◽  
Simranpreet Kaur ◽  
R.K. Gupta
Keyword(s):  
Seed Yield ◽  
Surface Soil ◽  
Cropping Systems ◽  
Cropping System ◽  
P Uptake ◽  
Spring Maize ◽  
Stover Yield ◽  
Glycine Max L ◽  
The Mean ◽  
Optimum Production

Background: Soybean-wheat is the most dominant soybean based cropping system and it also fits well in soybean-spring maize and soybean-gobhi sarson cropping systems. Soybean being a highly nutrient-exhaustive crop requires higher amounts of nutrients, particularly phosphorus for its optimum production. Thus, the present investigation was undertaken. Methods: A field experiment was conducted for three years to study the effect of phosphorous application on yield and P uptake by soybean in different cropping systems. There were three cropping systems which were kept in main plots and five P levels viz., 0, 20, 40, 60 and 80 kg P2O5 ha-1 applied to soybean which were kept in the sub plot. Result: Application of 80 kg P2O5 ha-1 resulted in highest mean seed yield of soybean (20.9 qha-1) but significant response was observed up to 40 kg P2O5 ha-1 (19.8 qha-1) only. Highest mean seed P uptake of soybean was observed under application of 80 kg P2O5 ha-1. The mean seed yield, stover yield and P uptake of soybean was not affected significantly under different cropping systems. The interaction effects of cropping system and applied P levels were however non-significant. A significant build-up of available P in surface soil over control was observed under 80 kg P2O5 ha-1 level.

scholarly journals Seasonal and spatial variation of bacterial production and abundance in the northern Levantine Sea

2017 ◽  
Vol 18 (1) ◽  
pp. 97 ◽  
Author(s):  
N. YUCEL
Keyword(s):  
Bacterial Production ◽  
Bacterial Abundance ◽  
Phytoplankton Bloom ◽  
Euphotic Zone ◽  
Organic Carbon Content ◽  
Spring Phytoplankton Bloom ◽  
Levantine Sea ◽  
Spatial And Temporal Heterogeneity ◽  
The Mean ◽  
Mean Time

Spatial and temporal heterogeneity in bacterial production and abundance in relation to ambient bio-physicochemical parameters has been investigated in the Levantine Sea. Five stations with different trophic states in an area extending from highly eutrophic Mersin bay to the mesotrophic Rhodes gyre area including the oligotrophic offshore waters were sampled four times. Integrated bacterial production varied between 6.1 and 90.3 µg C m-2 d-1 with higher rates occurring during September 2012 in offshore waters. Bacterial abundance ranged between 0.18 and 7.3 x 105 cells ml-1 within the euphotic zone and was generally higher up to 100 meters throughout the study period. In offshore waters, bacterial production (0.401 to 0.050 µg C m-3 d-1), abundance (4.5 to 1.6 x 105 cells ml-1) and depth of the productive layer decreased from 150 to 75 meters westward along the transect. Although the highest abundance was observed in July 2012 in offshore waters, the highest activity was measured in September 2012. These results indicated that the temperature played a key role in regulating bacterial abundance and production in the area. High chlorophyll concentrations in March did not correspond to high bacterial abundance and production at the same time. Increase in dissolved organic carbon content following spring phytoplankton bloom and the increase in temperature in the mean time might have enhanced the bacterial activity towards summer.

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