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1.
We have examined whether assimilation of CO2 can be used as a measure of metabolic activity in planktonic and sessile heterotrophic bacteria. CO2 assimilation by environmental samples and pure cultures of heterotrophic bacteria was studied using 14CO2 and 13CO2 as tracers. Heterotrophic growth on complex organic substrates resulted in assimilation of CO2 into cell biomass by activated sludge, drinking water biofilm, and pure cultures of Escherichia coli ATCC 25922, Es. coli ATCC 13706, Rhodococcus ruber, Burkholderia sp., Bacillus circulans, Pseudomonas putida, Pseudomonas stutzeri, and Pseudomonas aeruginosa. Analysis of 13C-labelled phospholipid fatty acids (PLFAs) confirmed that heterotrophic bacteria may assimilate 13CO2 into cell macromolecules such as membrane lipids. All major PLFAs extracted from activated sludge and drinking water biofilm samples were enriched in 13C after incubation with CO2. Between 1.4% and 6.5% of the biomass produced by cultures of P. putida and a drinking water biofilm during growth in complex media was apparently derived from assimilation of CO2. Resting cells assimilated less CO2 compared to actively growing cells, and CO2 assimilation activity correlated with the amount of biomass produced during heterotrophic growth. The 14CO2 assimilation assay was evaluated as a tool to examine inhibitory effects of biocides on planktonic and sessile heterotrophs (biofilms). On the basis of 14CO2 assimilation activity, the minimum inhibitory concentration (MIC) of benzalkonium chloride was estimated to 21.1 and 127.2 mg l(-1) for planktonic and biofilm samples, respectively. The results indicate that assimilation of isotopically labelled CO2 can be used as a relatively simple measure of metabolic activity in heterotrophic bacteria. CO2 assimilation assays may be used to study the effects of antimicrobial agents on growth and survival of planktonic and sessile heterotrophic organisms. 相似文献
2.
A 1 μM solution of ammoniates [ZnCu(NH3)n]2+(CO3)2− was inserted into a cut shoot of flax with the transpiration stream of water. Analysis of the 14C content after 14CO2 assimilation by the shoot showed that ammoniates increased radioactive label contents in the tissues (especially in the young
leaves and stem). In the leaves the higher sucrose to hexoses ratio, an increased radioactivity of glycerate and malate and
decreased incorporation of 14C into oligosaccharides and pigments were observed. These effects were more pronounced in the young leaves. Spraying of plants
with 20 mM solution resulted in an increase of plant height and leaf number. 相似文献
3.
We demonstrate for the first time that the pathogenic bacteria Yersinia pseudotuberculosis and Listeria monocytogenes (pathogens of saprozoonoses) are capable of chemolithoautotrophic assimilation of CO2. Low temperature is favorable for better absorption of CO2 by these bacteria; this is supported by increased enzymatic activity of carbonic anhydrase acting as the supplier of the substrate to the site of carboxylation. Data of radioisotopic methods indicate that assimilated labeled carbon of CO2 is incorporated into all major cell biopolymers. The bacteria can utilize not only CO2, but also other C1-compounds for biosynthesis. 相似文献
4.
5.
Isotope Labeling and Microautoradiography of Active Heterotrophic Bacteria on the Basis of Assimilation of 14CO2
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Martin Hesselsoe Jeppe Lund Nielsen Peter Roslev Per Halkjr Nielsen 《Applied microbiology》2005,71(2):646-655
Most heterotrophic bacteria assimilate CO2 in various carboxylation reactions during biosynthesis. In this study, assimilation of 14CO2 by heterotrophic bacteria was used for isotope labeling of active microorganisms in pure cultures and environmental samples. Labeled cells were visualized by microautoradiography (MAR) combined with fluorescence in situ hybridization (FISH) to obtain simultaneous information about activity and identity. Cultures of Escherichia coli and Pseudomonas putida assimilated sufficient 14CO2 during growth on various organic substrates to obtain positive MAR signals. The MAR signals were comparable with the traditional MAR approach based on uptake of 14C-labeled organic substrates. Experiments with E. coli showed that 14CO2 was assimilated during both fermentation and aerobic and anaerobic respiration. The new MAR approach, HetCO2-MAR, was evaluated by targeting metabolic active filamentous bacteria, including “Candidatus Microthrix parvicella” in activated sludge. “Ca. Microthrix parvicella” was able to take up oleic acid under anaerobic conditions, as shown by the traditional MAR approach with [14C]oleic acid. However, the new HetCO2-MAR approach indicated that “Ca. Microthrix parvicella,” did not significantly grow on oleic acid under anaerobic conditions with or without addition of NO2−, whereas the addition of O2 or NO3− initiated growth, as indicated by detectable 14CO2 assimilation. This is a metabolic feature that has not been described previously for filamentous bacteria. Such information could not have been derived by using the traditional MAR procedure, whereas the new HetCO2-MAR approach differentiates better between substrate uptake and substrate metabolism that result in growth. The HetCO2-MAR results were supported by stable isotope analysis of 13C-labeled phospholipid fatty acids from activated sludge incubated under aerobic and anaerobic conditions in the presence of 13CO2. In conclusion, the novel HetCO2-MAR approach expands the possibility for studies of the ecophysiology of uncultivated microorganisms. 相似文献
6.
7.
Mohn J Szidat S Fellner J Rechberger H Quartier R Buchmann B Emmenegger L 《Bioresource technology》2008,99(14):6471-6479
A field application of the radiocarbon ((14)C) method was developed to determine the ratio of biogenic vs. fossil CO(2) emissions from waste-to-energy plants (WTE). This methodology can be used to assign the Kyoto relevant share of fossil CO(2) emissions, which is highly relevant for emission budgets and emission trading. Furthermore, heat and electricity produced by waste incinerators might be labelled depending on the fossil or biogenic nature of the primary energy source. The method development includes representative on-site CO(2) absorption and subsequent release in the laboratory. Furthermore, a reference value for the (14)C content of pure biogenic waste (f(M,bio)) was determined as 1.130+/-0.038. Gas samples for (14)CO(2) analysis were taken at three WTEs during one month each. Results were compared to an alternative approach based on mass and energy balances. Both methods were in excellent agreement and indicated a fraction of biogenic CO(2) slightly above 50%. 相似文献
8.
Hanba YT Shibasaka M Hayashi Y Hayakawa T Kasamo K Terashima I Katsuhara M 《Plant & cell physiology》2004,45(5):521-529
The internal conductance for CO(2) diffusion (g(i)) and CO(2) assimilation rate were measured and the related anatomical characteristics were investigated in transgenic rice leaves that overexpressed barley aquaporin HvPIP2;1. This study was performed to test the hypothesis that aquaporin facilitates CO(2) diffusion within leaves. The g(i) value was estimated for intact leaves by concurrent measurements of gas exchange and carbon isotope ratio. The leaves of the transgenic rice plants that expressed the highest levels of Aq-anti-HvPIP2;1 showed a 40% increase in g(i) as compared to g(i) in the leaves of wild-type rice plants. The increase in g(i) was accompanied by a 14% increase in CO(2) assimilation rate and a 27% increase in stomatal conductance (g(s)). The transgenic plants that had low levels of Aq-anti-HvPIP2;1 showed decreases in g(i) and CO(2) assimilation rate. In the plants with high levels of Aq-anti-HvPIP2;1, mesophyll cell size decreased and the cell walls of the epidermis and mesophyll cells thickened, indicating that the leaves had become xeromorphic. Although such anatomical changes could partially offset the increase in g(i) by the aquaporin, the increase in aquaporin content overcame such adverse effects. 相似文献
9.
10.
Effects of elevated [CO2] and/or ozone on limitations to CO2 assimilation in soybean (Glycine max) 总被引:3,自引:0,他引:3
Soybean (Glycine max) was grown in open-top field
chambers at ambient (360 mol
mol-1) or doubled [CO2] either in charcoal-filtered
air (20 nmol mol-1 [O3]) or in non-filtered air
supplemented to 1,5 x ambient [O3] (70 nmol mol-1)
to determine the major limitations to assimilation under conditions of
elevated [CO2] and/or [O3]. Through plant ontogeny, assimilation versus
intercellular CO2 concentration (A/Ci) responses were
measured to assess the limitations to assimilation imposed by the capacity
for Rubisco carboxylation, RuBP regeneration, and stomatal diffusion.In the
vegetative stages, no significant treatment effects of elevated [CO2]
and/or [O3] were observed on Rubisco carboxylation efficiency
(CE), light and CO2-saturated assimilation capacity
(Amax), and chlorophyll content
(Chl). However, for plants grown in elevated [CO2],
the assimilation rate at growth [CO2] (A) was 60%
higher than at ambient [CO2] up to the seed maturation stage, and the
potential rate of assimilation by Rubisco capacity
(Ap) was increased. Also in elevated [CO2]:
A was 51% of Ap; the relative
stomatal limitation (%Stomata) was 5%; and the
relative RuBP regeneration limitation (%RuBP) was 44%.
In ambient [CO2], O3 gradually decreased A per unit
leaf area, but had little effect on Ap and the
relative limitations to assimilation where A remained
51% of Ap, %Stomata was 27%, and
%RuBP was 22%.During reproduction,
CE declined for plants grown in elevated [CO2] and/or
[O3]; Ap was unaffected by elevated [CO2], but was
reduced by [O3] at ambient [CO2]; A increased to 72%
of Ap in elevated [CO2] and/or [O3]-fumigated air; the
%Stomata increased; and the %RuBP
decreased, to become non significant in elevated [CO2] from the beginning
of seed growth on, and in O3-fumigated air at ambient [CO2] at the seed
maturation stage. The decrease in %RuBP occurred
concomitantly with an increase in Amax and
Chl. Significant [CO2] x [O3] interactions support the
lack of an O3 effect on assimilation and its limitations at elevated [CO2]
during seed maturation. These data suggest that elevated [CO2] alleviated
some of the effects of O3 on photosynthesis.Keywords:
CO2 by O3 interactions, elevated [CO2], O3 fumigation, Rubisco
carboxylation efficiency, RuBP regeneration.
相似文献
11.
Bacterial mortality was studied using two complementary methods between 2002 and 2004 in the two main basins (north and south) of Lake Tanganyika. The disappearance of radioactivity from the DNA of natural assemblages of bacteria previously labeled with tritiated thymidine was used to estimate the mortality due to grazing by predators (72%) and due to the cell lysis (28%). Measurements of ingestion rate of bacteria by protozoa using fluorescent micro-particles yielded protozoan grazing rates similar to those provided by the thymidine method, and showed that heterotrophic nano-flagellates were responsible for most of the grazing pressure on the bacterial community of the pelagic zone (92-99%). Bacterial cell lysis was the second process involved in bacterial mortality, ranking before ciliate grazing. Overall, bacterial mortality was balanced with bacterial production. With regard to the assessment of the trophic role of bacteria, it was estimated that c. 5-8% of the organic carbon taken up by bacteria was converted into protozoan biomass and was thus available for metazoans. 相似文献
12.
13.
A heterotrophic semisolid medium was used with two sensitive assay methods, C(2)H(2) reduction and O(2)-dependent tritium uptake, to determine nitrogenase and hydrogenase activities, respectively. Organisms known to be positive for both activities showed hydrogenase activity in both the presence and absence of 1% C(2)H(2), and thus, it was possible to test a single culture for both activities. Hydrogen uptake activity was detected for the first time in N(2)-fixing strains of Pseudomonas stutzeri. The method was then applied to the most-probable-number method of counting N(2)-fixing and H(2)-oxidizing bacteria in some natural systems. The numbers of H(2)-oxidizing diazotrophs were considerably higher in soil surrounding nodules of white beans than they were in the other systems tested. This observation is consistent with reports that the rhizosphere may be an important ecological niche for H(2) transformation. 相似文献
14.
Marianne Mousseau 《Photosynthesis research》1986,8(2):187-191
Summary Plantlets of Nicotiana tabacum (var. Samsun) were grown under CO2 enriched air supplied by a Warburg buffer. Growth of all plant parts was enhanced. The maximum growth increase was found for roots (120%).Addition of 30 g.l-1 sucrose in the medium resulted in a three time faster growth. However, the effect of CO2 enrichment was still positive in these conditions, although less pronounced than in autotrophic cultures. 相似文献
15.
The influence of solar ultraviolet radiation and photosynthetically active radiation (PAR) on summertime marine bacterial uptake and assimilation of sulfur from radiolabeled dimethlysulfoniopropionate (35S-DMSP) was studied at four Arctic and two Antarctic stations. Incubations with 3H-leucine were also conducted for comparative purposes as a measurement of bacterial activity. Arctic waters were characterized by large numbers of colonial Phaeocystis pouchetii and higher DMSP concentrations than in the two diatom-dominated Antarctic samples. Exposure to full sunlight radiation (280–700?nm), and to a lesser extent to PAR?+?UVA (320–700?nm), generally decreased the bacterial assimilation of 3H-leucine with respect to darkness, and caused variable effects on 35S-DMSP assimilation. By using a single-cell approach involving microautoradiography we found high percentages of sulfur assimilating cells within the bacterial groups Gammaproteobacteria, Bacteroidetes, SAR11 and Roseobacter despite the varying DMSP concentrations between Arctic and Antarctic samples. The dominant SAR11 clade contributed 50–70% of the cells assimilating both substrates in the Arctic stations, whereas either Gammaproteobacteria or SAR11 were the largest contributors to 3H-leucine uptake in samples from the two Antarctic stations. Only one station was analyzed for single-cell 35S-DMSP assimilation in Antarctica, and Gammaproteobacteria were major contributors to its uptake, providing the first evidence for Antarctic bacteria actively taking up 35S-DMSP. PAR?+?UVA repeatedly increased the number of SAR11 cells assimilating 3H-leucine. This pattern also occurred with other 35S-DMSP assimilating groups, though not so consistently. Our results support a widespread capability of polar bacteria to assimilate DMSP-sulfur during the season of maximum DMSP concentrations, and show for the first time that all major polar taxa can be highly active at this assimilation under the appropriate circumstances. Our findings further confirm the role of sunlight as a modulator of heterotrophic carbon and sulfur fluxes in the surface ocean. 相似文献
16.
17.
Autotrophic CO2 assimilation and the evolution of ribulose diphosphate carboxylase 总被引:18,自引:0,他引:18
B A McFadden 《Bacteriological reviews》1973,37(3):289-319
18.
Feisthauer S Wick LY Kästner M Kaschabek SR Schlömann M Richnow HH 《Environmental microbiology》2008,10(6):1641-1651
Motivated by the finding that Pseudomonas knackmussii B13 but not Rhodococcus opacus 1CP grows in the absence of externally provided CO(2), we investigated the assimilation of (13)CO(2) into active cells cultivated with non-labelled glucose as sole energy substrate. (13)C found in the bulk biomass indicated a substantial but different CO(2) assimilation by Pseudomonas and Rhodococcus, respectively (3500 per thousand and 2600 per thousand). Cellular fatty acids were labelled from -15 per thousand to 470 per thousand and amino acids from 500 per thousand to 24,000 per thousand demonstrating clear differences between various compound classes. 'You are what you eat plus 1 per thousand' is therefore only valid for the average bulk C without specific isotope signature deviation of the external CO(2) or carbonates. Odd-numbered and 10-methyl fatty acids, which are much more abundant in Rhodococcus or other Gram-positive bacteria, were up to fivefold higher enriched in (13)C relative to the Pseudomonas fatty acids. A high-level growth-phase-independent, labelling of the oxaloacetate-derived amino acids indicated heterotrophic CO(2) fixation by anaplerotic reactions known to replenish the tricarboxylic acid cycle. Although both strains assimilate CO(2) via similar general pathways, Rhodococcus depends to a much higher extent on carboxylations reactions with external CO(2) owing to the formation of odd-numbered fatty acids. As a general consequence, heterotrophic fixation of CO(2) should be taken into account in investigations of degradation experiments using isotope tracer compounds. 相似文献
19.
Understanding how photosynthetic capacity acclimatises when plants are grown in an atmosphere of rising CO2 concentrations will be vital to the development of mechanistic models of the response of plant productivity to global environmental change. A limitation to the study of acclimatisation is the small amount of material that may be destructively harvested from long-term studies of the effects of elevation of CO2 concentration. Technological developments in the measurement of gas exchange, fluorescence and absorption spectroscopy, coupled with theoretical developments in the interpretation of measured values now allow detailed analyses of limitations to photosynthesisin vivo. The use of leaf chambers with Ulbricht integrating spheres allows separation of change in the maximum efficiency of energy transduction in the assimilation of CO2 from changes in tissue absorptance. Analysis of the response of CO2 assimilation to intercellular CO2 concentration allows quantitative determination of the limitation imposed by stomata, carboxylation efficiency, and the rate of regeneration of ribulose 1:5 bisphosphate. Chlorophyll fluorescence provides a rapid method for detecting photoinhibition in heterogeneously illuminated leaves within canopies in the field. Modulated fluorescence and absorption spectroscopy allow parallel measurements of the efficiency of light utilisation in electron transport through photosystems I and IIin situ.Abbreviations A
net rate of CO2 uptke per unit leaf area (µmol m–2 s–1)
- Asat
light-saturated A
- A820
change in absorptance of PSI on removal of illumination (OD)
- c
CO2 concentration in air (µmol mol–1)
- ca
c in the bulk air; ci, c in the intercellular spaces
- ce
carboxylation efficiency (mol m–2 s–1)
- E
transpiration per unit leaf area (mol m–2 s–1)
- F
fluorescence emission of PSII (relative units)
- Fm
maximal level of F
- Fo
minimal level of F upon illumination when PSII is maximally oxidised
- Fs
the steady-state F following the m peak
- Fv
the difference between Fm and Fo
- F'm
maximal F' generated after the m peak by addition of a saturating light pulse
- F'o
the minimal level of F' after the m peak determined by re-oxidising PSII by far-red light
- g1
leaf conductance to CO2 diffusion in the gas phase (mol m–2 s–1)
- g'1
leaf conductance to water vapour diffusion in the gas phase (mol m–2 s–1)
- kc and ko
the Michaelis constants for CO2 and O2, respectively, (µmol mol–1);
- Jmax
the maximum rate of regeneration of rubP (µmol m–2 s–1)
- l
stomatal limitation to CO2 uptake (dimensionless, 0–1)
- LCP
light compensation point of photosynthesis (µmol m–2 s–1)
- oi
the intercellular O2 concentration (mmol mol–1)
- Pi
cytosol inorganic phosphate concentration
- PSI
photosystem I
- PSII
photosystem II
- Q
photon flux (µmol m–2 s–1)
- Qabs
Q absorbed by the leaf
- rubisCO
ribulose 1:5 bisphosphate carboxylase/oxygenase; rubP, ribulose 1:5 bisphosphate; s, projected surface area of a leaf (m2)
- Vc,max
is the maximum rate of carboxylation (µmol m–2 s–1)
- Wc
the rubisCO limited rate of carboxylation (µmol m–2 s1)
- Wj
the electron transport limited rate of regeneration of rubP (µmol m–2 s–1)
- Wp
the inorganic phosphate limited rate of regeneration of rubP (µmol m–2 s–1)
-
absorptance of light (dimensionless, 0–1)
- a
of standard black absorber 1, of leaf
- s
of integrating sphere walls
- , CO2
compensation point of photosynthesis (µmol mol–1)
-
the specificity factor for rubisCO carboxylation (dimensionless)
- ,
convexity of the response of A to Q (dimensionless 0–1)
-
the quantum yield of photosynthesis on an absorbed light basis (A/Qabs; dimensionless)
-
the quantum yield of photosynthesis on an incident light basis (A/Q; dimensionless)
- app
the maximum
- m
the maximum
- m,app
the photochemical efficiency of PSII (dimensionless, 0–1)
- PSII,m
the maximum 相似文献
20.
The small-scale production of [U-14C]acetylene from Ba14CO3: application to labeling of ammonia monooxygenase in autotrophic nitrifying bacteria 总被引:4,自引:0,他引:4
A small-scale method has been adapted from an established procedure for the generation of [U-14C]acetylene from inexpensive and commonly available precursors. The method involves the fusing of Ba14CO3 with excess barium metal to produce Ba14C2. The BaC2 is reacted with water to generate acetylene which is then selectively dissolved into dimethyl sulfoxide (DMSO). The results presented demonstrate the effect of Ba:BaCO3 ratio on the concentrations of various gases released during the hydrolysis reaction and quantify the selectivity of the DMSO-trapping process for each gas. [U-14C]Acetylene generated by this method has been used to inactivate ammonia monooxygenase in three species of autotrophic nitrifying bacteria: Nitrosomonas europaea, Nitrosococcus oceanus, and Nitrosolobus multiformis. Our results demonstrate that acetylene inactivation of this enzyme in all three species results in the covalent incorporation of radioactive label into a polypeptide of apparent Mr of 25,000-27,000, as determined by sodium dodecylsulfate-polyacrylamide gel electrophoresis and fluorography. 相似文献