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1.
Anaerobic Biodegradation of the Lignin and Polysaccharide Components of Lignocellulose and Synthetic Lignin by Sediment Microflora 总被引:13,自引:8,他引:5
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Specifically radiolabeled [14C-lignin]lignocelluloses and [14C-polysaccharide]lignocelluloses were prepared from a variety of marine and freshwater wetland plants including a grass, a sedge, a rush, and a hardwood. These [14C]lignocellulose preparations and synthetic [14C]lignin were incubated anaerobically with anoxic sediments collected from a salt marsh, a freshwater marsh, and a mangrove swamp. During long-term incubations lasting up to 300 days, the lignin and polysaccharide components of the lignocelluloses were slowly degraded anaerobically to 14CO2 and 14CH4. Lignocelluloses derived from herbaceous plants were degraded more rapidly than lignocellulose derived from the hardwood. After 294 days, 16.9% of the lignin component and 30.0% of the polysaccharide component of lignocellulose derived from the grass used (Spartina alterniflora) were degraded to gaseous end products. In contrast, after 246 days, only 1.5% of the lignin component and 4.1% of the polysaccharide component of lignocellulose derived from the hardwood used (Rhizophora mangle) were degraded to gaseous end products. Synthetic [14C]lignin was degraded anaerobically faster than the lignin component of the hardwood lignocellulose; after 276 days, 3.7% of the synthetic lignin was degraded to gaseous end products. Contrary to previous reports, these results demonstrate that lignin and lignified plant tissues are biodegradable in the absence of oxygen. Although lignocelluloses are recalcitrant to anaerobic biodegradation, rates of degradation measured in aquatic sediments are significant and have important implications for the biospheric cycling of carbon from these abundant biopolymers. 相似文献
2.
The seeds of Heimia salicifolia do not contain alkaloids. Two unidentified alkaloids were detected in 1-week-old seedlings; these alkaloids were absent from older plant samples. Lyfoline, cryogenine, and lythrine were first detected in 2-week-old plants. Sinicuichine was first observed in 3-week-old plants and nesodine in 2-month-old plants. The maximum rates of synthesis for most of these alkaloids occurred in 1- to 2-month-old plants. Following administration of 14CO2 to H. salicifolia plants, small quantities of alkaloids were purified to constant specific activity without alkaloid dilution; 95.6% of the administered 14CO2 was assimilated and up to 0.16% of this activity was incorporated into known alkaloids. Sinicuichine and lyfoline were shown to undergo catabolism, while cryogenine was degraded very slowly, if at all. Evidence is presented for the conversion of lyfoline to lythrine. 相似文献
3.
Richard L. Smith Frances E. Strohmaier Ronald S. Oremland 《Archives of microbiology》1985,141(1):8-13
Enrichment cultures that anaerobically degraded oxalate were obtained from lake sediment inocula. From these, 5 pure cultures of anaerobic oxalate-degrading bacteria were isolated and partially characterized. The isolates were Gram-negative, non-sporeforming, non-motile, obligate anaerobes. Oxalate was required for growth and was stoichiometrically converted to formate; 14CO2 was also recovered when 14C-oxalate was added. Maximal growth occurred when the oxalate concentration was 50 mM. Acetate stimulated growth in the presence of oxalate, however, 14C-experiments indicated that acetate was only utilized for cell carbon.The isolates were either spiral-shaped or rod-shaped organisms. The first morphotype grew much more slowly than the second and exhibited 13-fold lower cell yields. These isolates represent a new strain of oxalate-degrading bacteria. The second morphotype was similar to the anaerobic oxalate-degrading bacteria previously found in rumen. This report extends the known habitats in which anaerobic oxalate-degrading organisms have been found to include aquatic sediments. 相似文献
4.
Metabolism of EDTA and its metal chelates by whole cells and cell-free extracts of strain BNC1 总被引:5,自引:0,他引:5
The influence of metal ions on the metabolism of ethylenediaminetetraacetate (EDTA) by whole cells and cell-free extracts
of strain BNC1 was investigated. Metal-EDTA chelates with thermodynamic stability constants below 1012 were readily mineralized by whole cells with maximum specific turnover rates of 15 (MnEDTA) to 20 (Ca-, Mg-, and BaEDTA)
μmol g protein−1 min−1. With the exception of ZnEDTA, chelates with stability constants greater than 1012 were not oxidized at a significant rate. However, it was shown for Fe(III)EDTA that even strong complexes can be degraded
after pretreatment by addition of calcium and magnesium salts in the pH range 9–11. The range of EDTA chelates converted by
cell-free extracts of strain BNC1 did not depend on their thermodynamic stabilities. The EDTA chelates of Ba2+, Co2+, Mg2+, Mn2+, and Zn2+ were oxidized whereas Ca-, Cd-, Cu-, Fe-, Pb-, and SnEDTA were not. The first catabolic enzyme appears to be an EDTA monooxygenase
since it requires O2, NADH, and FMN for its activity and yields glyoxylate and ethylenediaminetriacetate as products. The latter is further degraded
via N,N′-ethylenediaminediacetate. The maximum specific turnover rate with MgEDTA, the favoured EDTA species, was 50–130 μmol g protein−1 min−1, and the K
m value was 120 μmol/l (K
s for whole cells = 8 μmol/l). Whole cells as well as cell-free extracts of strain BNC1 also converted several structural analogues
of EDTA.
Received: 4 July 1997 / Received revision: 25 September 1997 / Accepted: 29 September 1997 相似文献
5.
Bacterial Degradation of EDTA 总被引:1,自引:0,他引:1
Satroutdinov A. D. Dedyukhina E. G. Chistyakova T. I. Minkevich I. G. Eroshin V. K. Egli T. 《Microbiology》2003,72(1):8-11
Degradation of EDTA (ethylenediaminetetraacetic acid) or metal–EDTA complexes by cell suspensions of the bacterial strain DSM 9103 was studied. The activity of EDTA degradation was the highest in the phase of active cell growth and decreased considerably in the stationary phase, after substrate depletion in the medium. Exponential-phase cells were incubated in HEPES buffer (pH 7.0) with 1 mM of uncomplexed EDTA or EDTA complexes with Mg2+, Ca2+, Mn2+, Pb2+, Co2+, Cd2+, Zn2+, Cu2+, or Fe3+. The metal–EDTA complexes (Me–EDTA) studied could be divided into three groups according to their degradability. EDTA complexes with stability constants K below 1016 (log K < 16), such as Mg–EDTA, Ca–EDTA, and Mn–EDTA, as well as uncomplexed EDTA, were degraded by the cell suspensions at a constant rate to completion within 5–10 h of incubation. Me–EDTA complexes with log K above 16 (Zn–EDTA, Co–EDTA, Pb–EDTA, and Cu–EDTA) were not completely degraded during a 24-h incubation, which was possibly due to the toxic effect of the metal ions released. No degradation of Cd–EDTA or Fe(III)–EDTA by cell suspensions of strain DSM 9103 was observed under the conditions studied. 相似文献
6.
From soil samples of different origin (field, grassland and forest soils) small numbers ofNocardin andPseudomonas spec., able to utilize benzene and phenol could be isolated. Organisms which could only utilize phenol and phenolcarboxylic acids were more numerous and consisted mainly ofArthrobacter spec. It was tested to what extent these organisms could also utilize chlorinated aromatic and cyclohexane derivatives. For the degradation studies the bacteria were precultivated on benzene or p-hydroxybenzoic acid and then the compounds used were added. These compounds were labeled by14C and their degradation rates determined by measuring the14CO2 release.Pseudomonas andNocardia spec. precultivated on benzene could also degrade the chlorinated derivatives of benzene and phenol. The monochlorinated derivates were degraded more easily than the di- and trichlorinated derivates. The chlorinated benzenes, especially in higher concentrations, were less degraded than the chlorinated phenols, but with lower concentrations their degradation rates were about similar. This was due to a higher toxicity of the benzenes. The phenol utilizingArthrobacter spec. were only able to degrade phenol and the chlorinated phenols. Benzoic and m-chlorobenzoic acid were degraded to CO2 by thePseudomonas andNocardia spec. only. The benzene utilizing pseudomonads released more CO2 from γ-pentachlorocyclohexane than from γ-hexachlorocyclohexane, but none from cyclehexane. Upon precultivation of benzene utilizing pseudomonads in glucose, the aromatic compounds were also degraded, but especially the chlorinated derivatives to a lower extent. In comparison with these soil organisms in pure culture, experiments with soil samples showed a degradation of all compounds which were used by the isolated organisms after variable induction periods. Cyclohexane was degraded slowly to CO2 by the mixed soil flora in contrast to the benzene or phenol utilizing pure cultures. 相似文献
7.
Effect of Mineral and Organic Soil Constituents on Microbial Mineralization of Organic Compounds in a Natural Soil 总被引:5,自引:2,他引:3
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David B. Knaebel Thomas W. Federle Drew C. McAvoy J. Robie Vestal 《Applied microbiology》1994,60(12):4500-4508
This research addressed the effect of mineral and organic soil constituents on the fate of organic compounds in soils. Specifically, it sought to determine how the associations between organic chemicals and different soil constituents affect their subsequent biodegradation in soil. Four 14C-labeled surfactants were aseptically adsorbed to montmorillonite, kaolinite, illite, sand, and humic acids. These complexes were mixed with a woodlot soil, and 14CO2 production was measured over time. The mineralization data were fitted to various production models by nonlinear regression, and a mixed (3/2)-order model was found to most accurately describe the mineralization patterns. Different mineralization patterns were observed as a function of the chemical and soil constituents. Surfactants that had been preadsorbed to sand or kaolinite usually showed similar mineralization kinetics to the control treatments, in which the surfactants were added to the soil as an aqueous solution. Surfactants that had been bound to illite or montmorillonite were typically degraded to lesser extents than the other forms, while surfactant-humic acid complexes were degraded more slowly than the other forms. The desorption coefficients (Kd) of the soil constituent-bound surfactants were negatively correlated with the initial rates of degradation (k1) and estimates of 14CO2 yield (Po) as well as actual total yields of 14CO2. However, there was no relationship between Kd and second-stage zero-order rates of mineralization (ko). Microbial community characteristics (biomass and activity) were not correlated with any of the mineralization kinetic parameters. Overall, this study showed that environmental form had a profound effect on the ultimate fate of biodegradable chemicals in soil. This form is defined by the physicochemical characteristics of the chemical, the composition and mineralogy of the soil, and the mode of entry of the chemical into the soil environment. 相似文献
8.
Aerobic Mineralization of Trichloroethylene, Vinyl Chloride, and Aromatic Compounds by Rhodococcus Species 总被引:3,自引:2,他引:1
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K. J. Malachowsky T. J. Phelps A. B. Teboli D. E. Minnikin D. C. White 《Applied microbiology》1994,60(2):542-548
Two Rhodococcus strains which were isolated from a trichloroethylene (TCE)-degrading bacterial mixture and Rhodococcus rhodochrous ATCC 21197 mineralized vinyl chloride (VC) and TCE. Greater than 99.9% of a 1-mg/liter concentration of VC was degraded by cell suspensions. [1,2-14C]VC was degraded by cell suspensions, with the production of greater than 66% 14CO2 and 20% 14C-aqueous phase products and incorporation of 10% of the 14C into the biomass. Cultures that utilized propane as a substrate were able to mineralize greater than 28% of [1,2-14C]TCE to 14CO2, with approximately 40% appearing in 14C-aqueous phase products and another 10% of 14C incorporated into the biomass. VC degradation was oxygen dependent and occurred at a pH range of 5 to 10 and temperatures of 4 to 35°C. Cell suspensions degraded up to 5 mg of TCE per liter and up to 40 mg of VC per liter. Propane competitively inhibited TCE degradation. Resting cell suspensions also degraded other chlorinated aliphatic hydrocarbons, such as chloroform, 1,1-dichloroethylene, and 1,1,1-trichloroethane. The isolates degraded a mixture of aromatic and chlorinated aliphatic solvents and utilized benzene, toluene, sodium benzoate, naphthalene, biphenyl, and n-alkanes ranging in size from propane to hexadecane as carbon and energy sources. The environmental isolates appeared more catabolically versatile than R. rhodochrous ATCC 21197. The data report that environmental isolates of Rhodococcus species and R. rhodochrous ATCC 21197 have the potential to degrade TCE and VC in addition to a variety of aromatic and chlorinated aliphatic compounds either individually or in mixtures. 相似文献
9.
Dark Fixation of CO(2) by Crassulacean Plants: Evidence for a Single Carboxylation Step 总被引:8,自引:8,他引:0
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Malic acid isolated from Bryophyllum pinnatum (Lamk.) Oken (B. calycinum Salisb.), Bryophyllum tubiflorum Harv., Kalanchoë diagremontiana Hamet et Perrier and Sedum guatamalense Hemsl. after dark 14CO2 fixation was degraded by an in vitro NADP-malic enzyme technique. In the short term (5 to 30 seconds) the malic acid was almost exclusively labeled in the C-4 carboxyl carbon (greater than 90%). The percentage of 14C in the C-4 carboxyl of malic acid declined slowly with time, reaching 70% in B. tubiflorum and 54% in B. pinnatum after 14 hours of exposure to 14CO2. It was found that malic acid-adapted Lactobacillus arabinosus may seriously underestimate the C-4 carboxyl component of label in malic acid-14C. The amount of substrate which the bacteria can completely metabolize was easily exceeded; there was a significant level of randomization of label even when β-decarboxylation proceeded to completion, and in extended incubation periods, more than 25% of label was removed from malic acid-U-14C. The significance of these findings in relation to pathways of carbohydrate metabolism and malic acid synthesis in Crassulacean acid metabolism is discussed. 相似文献
10.
V.W.M. Van Hinsbergh J.H. Veerkamp H.Th.B. Van Moerkerk 《Archives of biochemistry and biophysics》1978,190(2):762-771
Oxidation of palmitate by rat skeletal muscle mitochondria was determined polarographically and radiochemically under state 3 conditions. Maximal oxidation rate is reached at 4 μm palmitate, palmitoyl-CoA, or palmitoyl-l-carnitine. At palmitoyl-CoA concentrations higher than 30 μm oxidation is inhibited. At limiting substrate concentrations as used in polarographic experiments palmitate is totally degraded to CO2. At higher concentrations the palmitate molecule is only partially degraded, due to the accumulation of intermediates. Citric acid cycle intermediates, especially 2-oxoglutarate, accumulate during oxidation of palmitate in the presence of malate. It is suggested that this accumulation is stimulated by dicarboxylate exchange. The rate of formation of 14CO2 and 14C-labeled perchloric acid-soluble products is higher from [1-14C]palmitate than that from [U-14C]palmitate. This difference, which is enhanced by higher carnitine concentrations indicates incomplete oxidation during the β-oxidation in state 3. The simultaneous determination of 14CO2 production and 14C-labeled perchloric acid-soluble products appears to be a more accurate and sensitive method for measuring 14C-fatty acid oxidation than that of 14CO2 production alone. 相似文献
11.
Summary Lignin biodegradation, carbon loss and in vitro dry matter digestibility (IVDMD) have been investigated during the solid state fermentation of wheat straw by eight previously selected strains of white-rot fungi. A mathematical model of the degradation kinetics is presented. [The time period required to reach maximum rates of 14CO2 and unlabeled CO2 release from (14C)-lignin-labelled wheat straw and from whole wheat straw, respectively, was generally short (6–10 days).] High rates of 14C-lignin degradation were achieved by Pycnoporus cinnabarinus (2.9% 14CO2 evolved/day), an unidentified strain Nancon (3.0%/day), Sporotrichum pulverulentum Nov. (3.4%/day), Bjerkandera adusta (2.4%/day), and Dichomitus squalens (2.3%). However, only the latter two strains degraded whole wheat straw slowly and Bjerkandera adusta was not able to degrade more than 23% of the 14C-lignin.
Cyathus stercoreus and Dichomitus squalens facilitated the highest improvement in IVDMD (68% against 38% for the sound straw) after 20 and 15 days of cultivation respectively, with low dry matter losses (15–20%). A study of the fate of 14C-lignin during fermentation using these two fungal strains showed that maximal levels of (14C)-water-soluble compounds are reached before peak levels of 14CO2 evolution suggesting that these compounds are intermediates in lignin degradation. A possible relationship between water-soluble lignins and IVDMD improvement is discussed. 相似文献
12.
Gp41 peptide antigen of the HIV-1 envelope (TP41-1:TPRGPDRPEGIEEEGGERDR, a highly conserved region) was enzymatically degraded by the antibody light chain 41S-2-L after an induction period. The peptide bond between Glu14 and Gly15 was cleaved early in the reaction. When EDTA was added in the induction period, it inhibited the degradation of TP41-1 thus ceasing the catalytic activity of 41S-2-L. In contrast, when EDTA was added after the induction period, only a small reduction in the catalytic activity was observed. These observations suggest that metal ions are important in stimulating catalytic activity early in the reaction. 相似文献
13.
Atrial natriuretic peptide (ANP) is a fluid-regulating peptide hormone that promotes vasorelaxation, natriuresis, and diuresis. The mechanisms for the release of ANP and for its clearance from the circulation play important roles in modulating its biological effects. Recently, we have reported that the cell surface of an endothelial cell line, CPA47, could degrade 125I-ANP in the presence of EDTA. In this study, we have characterized this degradation of 125I-ANP. The kinetics of ANP degradation by the surface of CPA47 cells were first order, with a Km of 320 ± 60 nM and Vmax of 35 ± 14 pmol of ANP degraded/10 min/105 cells at pH 7.4. ANP is degraded by the surface of CPA47 cells over a broad pH range from 7.0–8.5. Potato carboxypeptidase inhibitor and bestatin inhibited 125I-ANP degradation, suggesting that this degradative activity on the surface of CPA47 cells has exopeptidase characteristics. The selectivity of CPA47 cell-surface degradation of ANP was demonstrated when 125I-ANP degradation was inhibited in the presence of neuropeptide Y and angiotensin I and II but not bradykinin, bombesin, endothelin-1, or substance P. The C-terminal amino acids phe26 and tyr28 were deduced to be important for ANP interaction with the cell-surface peptidase(s) based on comparison of the IC50 of various ANP analogues and other natriuretic peptides for the inhibition of ANP degradation. These data suggest that a newly characterized divalent cation-independent exopeptidase(s) that selectively recognizes ANP and some other vasoactive peptides exists on the surface of endothelial cells. 相似文献
14.
D D Hackney 《Biochemical and biophysical research communications》1979,91(1):233-238
The soluble mitochondrial ATPase, F1, can be slowly inactivated by incubation with Mg+2 in a manner consistent with the observations of Moyle and Mitchell , 55 (1975)). This inhibition results in a low initial rate of ATP hydrolysis upon addition to an ATPase assay medium of F1 which has been incubated with Mg+2. This inhibition, however, is completely reversible by Mg·ATP in a time dependent process and results in the rate of ATP hydrolysis increasing during the ATPase assay to reach control levels after 30 sec. The length of the lag is independent of the F1 concentration in the ATPase assay and the lag is also completely reversed by subsequent incubation with excess EDTA before assay.F1 is unstable if incubated with EDTA in the absence of free nucleotides or Mg+2. The rate of inactivation increases with decreasing protein concentration until a limiting rate is reached at high dilution. Mg+2 in excess of the EDTA or 50 μM ADP stabilize the F1 against the inactivation but cannot reverse prior denaturation. 相似文献
15.
Michael A. Heitkamp James P. Freeman Dwight W. Miller Carl E. Cerniglia 《Archives of microbiology》1991,156(3):223-230
The metabolism of 14C-labeled 1-nitropyrene in microcosms containing nonsterile estuarine sediments, and in cultures of a Mycobacterium sp. previously isolated from oil-contaminated sediments was investigated. Although mineralization of 1-nitropyrene by pure cultures of the Mycobacterium sp. totaled only 12.3% after 10 days of incubation, over 80% of the ethyl acetate extractable 14C-labeled compounds consisted of 1-nitropyrene metabolites. High pressure liquid chromatographic analysis of 1-nitropyrene degradation products indicated that two major metabolites were formed. They were identified as 1-nitropyrene cis-9,10-and 4,5-dihydrodiols, based on their UV-visible, mass and NMR spectra. Time course studies in microcosms showed that 1-nitropyrene was degraded slowly under aerobic and anaerobic conditions in estuarine sediments. Less than 1% had been converted to 14CO2 after 8 weeks of aerobic incubation. The addition of 1-nitropyrene to anaerobic sediments resulted in no 14CO2 evolution; however, the nitro group of 1-nitropyrene was reduced to form 1-aminopyrene. Although the mineralization of 1-nitropyrene in sediments was slow, the Mycobacterium sp. metabolized 1-nitropyrene in pure culture. This bacterium appears promising for the bioremediation of this ubiquitous pollutant in contaminated waste.Abbreviations DEP
Direct exposure probe
- HPLC
high pressure liquid chromatography
- GC/MS
gas chromatography/mass spectrometry
- Nitro-PAHS
nitropolycyclic aromatic hydrocarbons
- TLC
thin-layer chromatography
- UV
ultraviolet 相似文献
16.
Changes in haemolymph proteins and lipoproteins during adipokinetic hormone action have been studied using polyacrylamide gel electrophoresis (PAGE) and a heparin/EDTA precipitation technique. During hormone action, the formation of A+ takes place at the expense of Ayellow and CL-proteins, which decrease in free concentration in the haemolymph. Ayellow is heparin precipitable, whereas A+ precipitates with EDTA after prior treatment with heparin. After injection of adipokinetic hormone, heparin-precipitable protein (HPP) decreases after a delay of 10–15 min, but heparin/EDTA precipitable protein (HEPP) increases immediately. These changes occur in response to extracts of corpora cardiaca and to synthetic adipokinetic hormone, and are dose-dependent. Both the lipid and the CL-protein content of the HEPP rise as its protein content increases. A+ formation does not occur in fifth-instar nymphs or newly emerged adults, but this response to adipokinetic hormone develops slowly as the adults mature. 相似文献
17.
The counting rate of [1-14C]trichloroacetic acid (TCA) was not stable in a standard toluene/Triton X-100 liquid scintillation solution because this compound becomes partially degraded to 14CO2 and CHCl3. Both toluene and Triton were contributing factors in causing this degradation. The NCS solubilizer added to the toluene/Triton scintillation solution trapped 14CO2 and stabilized counting rates of [1-14C]TCA. When [2-14C]TCA was used, 14CHCl3 remained in the scintillation solution resulting in stable counting rates without the addition of NCS. 相似文献
18.
A. D. Satroutdinov T. I. Chistyakova E. G. Dedyukhina E. N. Kaparullina V. K. Eroshin 《Applied Biochemistry and Microbiology》2005,41(5):469-473
A novel strain of bacteria (LPM-4) characterized by a unique EDTA requirement for cell growth was isolated. Suspensions of washed cells of strain LPM-4 degraded EDTA complexes with Ba2+, Mg2+, Ca2+, and Mn2+ at constant rates ( 0.310 ± 0.486 mmol EDTA/(g h)) and Zn-EDTA at an initial rate of 0.137 ± 0.016 mmol EDTA/(g h). The temperature optima for cell growth and EDTA degradation were determined under pH-auxostat cultivation. As compared with the known EDTA-degrading bacteria, strain LPM-4 exhibited a higher specific growth rate (0.095? 1) and lower mass cell yield (0.219 g cells/g EDTA), which is promising for its practical applications for EDTA removal in wastewater treatment plants. 相似文献
19.
Biphenyl was readily degraded and mineralized to CO2 and CH4 by a PCB-dechlorinating anaerobic microbial consortium. Degradation occurred when biphenyl was supplied as a sole source of carbon or as a co-metabolic substrate together with glucose and methanol. p-Cresol was detected and confirmed by mass spectroscopy as a transient intermediate. Production of 14 C-CO2 and 14C-CH4 from 14C-biphenyl was observed in the approximate ratio of 1:2. The results indicated the existence of novel pathways for biphenyl degradation in a natural anaerobic microbial community. 相似文献
20.
Summary Germinating jack bean cotyledons liberated 14CO2 when fed 14C-guanidoxy-canavanine but did not accumulate any 14C-compounds other than the applied canavanine. This suggested that the canavanine was being degraded by the action of canavanase to canaline and urea, the urea then being converted to ammonia and carbon dioxide by the action of urease. Hydroxyurea and acetohydroxamic acid (both inhibitors of urease activity) strongly inhibited the liberation of 14CO2 from 14C-guanidoxy-canavanine by the cotyledons but neither compound induced the accumulation of 14C-urea within the tissues. This inhibitory action of hydroxyurea on 14CO2 output was thought to be due at least in part, to this inhibition of canavanase activity. 相似文献