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1.
A Pseudomonas sp., isolated from soil, was grown aerobically on para-chloroaniline (PCA) as an only carbon and nitrogen source with a generation time of 15 hr. Balance studies with 14C-ring-labeled PCA revealed that 64% of the carbon of PCA was released as CO2 and 14% was associated with the biomass. For the ring substituents, 60% of the nitrogen and 96% of the chlorine of PCA accumulated in the medium as ammonium and chloride, respectively. The strain was also able to grow on aniline and 3-chloroaniline rapidly and 2-chloroaniline slowly as sole carbon and nitrogen sources. 相似文献
2.
Mixed populations of soil microorganisms were enriched in the presence of trifluralin (α,α,α-trifluoro-2,6-dinitro-N,N-dipropyl-p-toluidine) and 180 pure strains were subsequently isolated. About a third were able to liberate 1.5–6% 14CO2 from 0.15 mM [propyl-1-14C]trifluralin after growing for 21 days on a complex medium. One strain, identified as a Candida sp., showed a 14CO2 evolution of 11%. The amount of liberated 14CO2 could not be enhanced by adding small concentrations (<3%) of solvents to the culture, by varying the concentration of trifluralin, or by varying the composition of the complex medium. The Candida sp. was unable to cleave the aromatic ring of trifluralin or to use trifluralin as a sole source of carbon or nitrogen. Only traces (< 1%) of dealkylated trifluralin were accumulated in the culture. 相似文献
3.
[14C]-Labelled methazole, 1-(3,4-dichlorophenyl)-3-methylurea (DCPMU), 1-(3,4-dichlorophenyl)urea (DCPU), and diuron were incubated in soil at 20°C and field capacity soil moisture content. Decomposition followed first-order kinetics; half-lives for degradation of these four compounds were 2.4, 144, 30 and 108 days respectively. The amount of DCPMU and DCPU that could be extracted decreased with time and the decrease was accompanied by the generation of an equivalent amount of 14CO2. This was not so in the studies with diuron and methazole, however, and the decrease in the concentrations of radioactivity extracted from soil treated with these compounds could not be entirely accounted for as carbon dioxide. It is concluded that the unextractable radiochemical that was present was DCPMU. Methazole appeared to be degraded through DCPMU to 3,4-dichloroaniline (DCA) with the production of only traces of DCPU. 相似文献
4.
《Pesticide biochemistry and physiology》1987,27(2):182-188
Aspergillus nidulans is able to hydrolyze the herbicide propanil (3′,4′-dichloropropionanilide) with liberation of 3′,4′-dichloroaniline. When the fungus is grown with or without propanil, the hydrolytic activity is identical, but can be increased by starving the mycelium either for carbon, nitrogen, or both carbon and nitrogen. The enzyme which is responsible of this activity is of the aryl acylamidase type (EC 3.5.1 aryl acylamine amidohydrolase). It is also active on propionanilide and acetanilide, two structural analogs of propanil. A value of Km = 0.13 mM has been obtained for propanil. Temperature optimum is 40°C, when assayed with propanil as substrate. Although the pH optimum is 8, there is a relatively high enzyme activity over a wide range of pH values between 7.8 and 10.2. Carbaryl has been found to effectively inhibit the enzyme activity on propanil (Ki = 0.03 mM). The results indicated that the properties of this aryl acylamidase from A. nidulans are very similar to those of enzymes isolated from a variety of organisms such as rice, mammals and the fungus Fusarium solani. 相似文献
5.
Growth of Penicillium digitatum was inhibited after a 40-min incubation in a culture medium containing 0.5 mM sec-butylamine, and the dry weight of the hyphae was 50% of the control value after 180 min. Respiration of the hyphae was reduced 13% after a 20-min contact with 0.5 mM sec-butylamine but this treatment did not influence the uptake of amino acids, glucose, or phosphate nor intensify the efflux of 33P- or 14C-labeled metabolites from the cells. The syntheses of cell walls and total lipids were inhibited 20–30% after a 90-min incubation with sec-butylamine, and nucleic acid synthesis was reduced to about 50% of the control value at this time. sec-Butylamine inhibited the incorporation of labeled carbon from [14C]glucose into the protein fraction of the hyphae to a greater degree than 14C derived from labeled proline, lysine, or leucine. These observations suggested that sec-butylamine interfered primarily with the intermediary metabolism of glucose rather than inhibiting a later stage of macromolecule synthesis. Hyphae incubated with [14C]glucose and sec-butylamine accumulated pyruvic acid to a level seven times greater than in control hyphae. Furthermore, sec-butylamine strongly inhibited 14CO2 evolution from hyphae metabolizing [14C]pyruvate whereas CO2 derived from acetate or glucose after a 45-min incubation was only slightly reduced by sec-butylamine. These observations implicate pyruvate oxidation as the primary site of sec-butylamine action in young hyphae of P. digitatum. 相似文献
6.
Degradation of ioxynil (4-hydroxy-3,5-diiodobenzonitrile) to CO2 was detected in a clay loam, high organic matter content soil. The majority of radioactivity was recovered as 14CO2 from both ring-labeled and cyano-labeled ioxynil; however, 14CO2 was always released from cyano-labeled ioxynil at a much faster initial rate. No 14CO2 was released in treated sterile soil, either aerobically or anaerobically. Production of 14CO2 from cyanolabeled and ring-labeled ioxynil was greatly inhibited by HgCl2 (10?5M), and p-chloromercuribenzoate (5 × 10?5M), but slightly inhibited by ferricyanide (10?4M). No 14CO2 was evolved from ring-labeled ioxynil under anaerobic conditions. These observations indicated that the degradation of ioxynil to CO2 in soil was a microbial action and was oxygen dependent. This is consistent with the known mechanism of oxygenases in degrading benzene rings. Anaerobically, a small amount of 14CO2 was released from cyano-labeled ioxynil. Thin-layer chromatographic analyses of the culture supernatant revealed that 3,5-diiodo-4-hydroxybenzamide and 3,5-diiodo-4-hydroxybenzoic acid were intermediate metabolites. 相似文献
7.
Enzymatically isolated leaf cells from navy beans (Phaseolus vulgaris L., cv. “Tuscola”) were used to study the effect of buthidazole (3-[5-(1,1-dimethylethyl)-1,3,4-thiadiazol-2-yl]-4-hydroxy-1-methyl-2-imidazolidinone) and tebuthiuron (N-[5-(1,1-dimethylethyl)-1,3,4-thiadiazol-2-yl]-N,N′-dimethylurea) on photosynthesis, protein, ribonucleic acid (RNA), and lipid synthesis. The incorporation of NaH14CO3, [14C]leucine, [14C]uracil, and [14C]acetic acid as substrates for the respective metabolic process was measured. Time-course and concentration studies included incubation periods of 30, 60, and 120 min and concentrations of 0.1, 1, 10, and 100 μM of both herbicides. Photosynthesis was very sensitive to both buthidazole and tebuthiuron and was inhibited in 30 min by 0.1 μM concentrations. RNA and lipid syntheses were inhibited 50 and 87%, respectively, by buthidazole and 42 and 64%, respectively, by tebuthiuron after 120 min at 100 μM concentration. Protein synthesis was not affected by any herbicide at any concentration or any exposure time period. The inhibitory effects of buthidazole and tebuthiuron on RNA and lipid syntheses may be involved in the ultimate herbicidal action of these herbicidal chemicals. 相似文献
8.
Soil enrichment studies were conducted with nitralin [4-(methylsulfonyl)-2,6-dinitro-N,N-dipropylaniline] with and without exogenous carbon and nitrogen. Bacterial isolates obtained were placed into three categories. Eight fungal isolates, notably Fusarium and Penicillium sp., were obtained from the enriched soil culture. Only one bacterial isolate (Erwinia trachelphila) and no fungal isolates appeared to degrade nitralin. The degradation product isolated was tentatively identified by TLC and radioautography as 4-(methylsulfonyl)-2,6-dinitrophenol. No 14CO2 evolution from ring-labelled nitralin was detected from any isolates tested. 相似文献
9.
The rapid effects of the herbicide EPTC (S-ethyl dipropylthiocarbamate) and the protectant DDCA (N,N-diallyl-2,2-dichloroacetamide) on [2-14C]acetate incorporation into lipids of maize cell cultures were studied in order to determine whether they act at similar sites of lipid synthesis. DDCA, at 0.05 mM and 0.1 mM, increased the incorporation of [2-14C]acetate into neutral lipids of a total lipid extract within 2 h. It had very little effect on the major polar lipid constituents. DDCA altered neither the distribution of label within the major lipid classes, nor turnover of the major lipids within 2 h. EPTC (0.1 mM) inhibited overall uptake of [2-14C]acetate into both neutral and polar lipids by about 30% after a 2-h incubation. The major polar lipid affected was an unidentified glycolipid. In addition to reducing the quantity of lipids synthesized, EPTC changed the lipid profile, altering the distribution of label, mainly within the neutral lipid fraction. A crude membrane fraction from maize cells contained both polar lipids and some neutral lipids. DDCA stimulated [2-14C]acetate incorporation into different lipid species. EPTC inhibited incorporation of [2-14C]acetate into both neutral and polar membrane lipids but altered significantly only its distribution into neutral lipids. DDCA (0.1 mM) given together with EPTC (0.2 mM) partially counteracted the effect of EPTC within the neutral lipid fraction. It is suggested that DDCA has a rapid effect on lipid synthesis, but it is probably not sufficient to account for the entire mode of action of the protectant. 相似文献
10.
R.E. Wilkinson 《Pesticide biochemistry and physiology》1985,23(1):95-101
l-[U-14C]sucrose accumulation by phloem sieve tube members (PSTM) of wheat (Triticum aestivum L. ‘Holley’) and sorghum (Sorghum bicolor L. ‘G522 DR’) was inhibited by the nonpermeant sulfhydryl inhibitor p-chloromercuribenzenesulfonic acid (PCMBS), and this inhibition was reversed by the permeant sulfhydryl protectants dithiothreitol (DTT) and dithioerythritol (DTE). S-Ethyl dipropylthiocarbamate (EPTC) (≤0.1 mM) did not inhibit [14C]sucrose accumulation by wheat or sorghum PSTM. N-N-Diallyl-2-chloroacetamide (CDAA) (1 mM) inhibited [14C]sucrose accumulation by sorghum but not by wheat PSTM. The inhibition of [14C]sucrose accumulation in sorghum PSTM by the membrane permeant CDAA was reversed by DTT. Sorghum growth was inhibited by <1 μM CDAA. Membrane permeant 2-chloroallyl diethyldithiocarbamate (CDEC) (0.1 mM) inhibited [14C]sucrose accumulation by PSTM of sorghum but not wheat. The inhibition of sucrose accumulation in sorghum PSTM by 0.1 mM CDEC was reversed by DDT. 相似文献
11.
Cells were isolated from the developing leaves of Ipomoea aquatica and Digitaria sanguinalis. The effects of phenoxy alkanoic acid herbicides on light-dependent 14CO2 fixation and oxygen evolution in these leaf cells were studied. (2,4-Dichlorophenoxy)acetic acid and (2,4,5-trichlorophenoxy) acetic acid (2,4,5-T and 2,4-D) caused a 20% stimulation of 14CO2 fixation at 0.8 × 10?5M and an inhibition at 1 × 10?4M in I. aquatica leaf cells. Temperature seemed to have a marked influence on such action. No effect or very little effect was observed in the leaf cells of D. sanguinalis. The nonactive (2,4,6-Trichlorophenoxy)acetic acid (2,4,6-T) caused a similar stimulation of CO2 fixation as 2,4-D and 2,4,5-T at low concentrations in I. aquatica leaf cells, but no inhibition was observed at high concentration. Increase of hight intensity increased the rate of CO2 fixation in both control and 2,4,6-T-treated cells; however, the percentage of stimulation remained the same. At stimulatory concentration, all three compounds did not cause any stimulation in either photosystem I and II or photosystem II-mediated oxygen evolution. At higher concentrations, the differential effects of 2,4-D and 2,4,5-T on the light-induced CO2 fixation and photosystem II-mediated oxygen evolution in the I. aquatica leaf cells and D. sanguinalis mesophyll (ms) cells may be attributed in part to their selective action against dicotyledonous plants. 相似文献
12.
Steven J. Roberts Allan Walker Nisha R. Parekh Sarah J. Welch Martin J. Waddington 《Pest management science》1993,39(1):71-78
A stable mixed bacterial culture which degrades the herbicide linuron was isolated from soil by enrichment with linuron in a liquid mineral medium. Radio-respirometry studies showed that the culture mineralised linuron completely. No intermediate degradation products were detected in the medium. The culture was able to utilise linuron as a source of both nitrogen and carbon and was also able to degrade the related herbicides monolinuron and chlorbromuron and the possible intermediate degradation products of linuron: 3,4-dichlorophenyl-l-methylurea, 3,4-dichlorophenylurea and 3,4-dichloroaniline. The culture was unable to degrade the 1,1-dimethyl substituted ureas monuron, diuron or metoxuron. The culture contained Gram-negative aerobic rods, and Gram-positive aerobic non-spore-forming rods and cocco-bacilli. Of 124 isolates from the mixed culture, none degraded linuron in pure culture, indicating that a consortium of organisms is involved. Further investigation suggested that Pseudomonas spp. were important components of the population responsible for degradation. 相似文献
13.
Cells were isolated from the developing leaves of Ipomoea aquatica (water spinach), a C3 plant, and three kinds of C4 plants, namely, Digitaria sanguinalis (NADP+-specific malate dehydrogenase type), Panicum miliaceum (NAD+-specific malic enzyme type), and Panicum texanum (phosphoenopyruvate carboxy kinase type), to study the effect of monuron on light-dependent 14CO2 fixation and oxygen evolution. Bundle sheath cells, except for those of D. sanguinalis, and mesophyll cells of all plants fixed approximately the same amount of 14CO2. Monuron, at the range used (2 to 10 × 10?7M), showed strong inhibition in the mesophyll cells of water spinach and in bundle sheath cells of P. miliaceum and P. texanum and moderate inhibition in the mesophyll cells of all C4 plants. In the bundle sheath cells of D. sanguinalis the low rate of 14CO2 fixation was stimulated to some extent by the addition of malate and ribose 5-phosphate. The I50 value was 6 × 10?7M for the sensitive cells. Monuron inhibited the oxygen evolution of all seven cell types and their I50 values varied between 3 × 10?7 to 6 × 10?7M. The differential response of isolated plant cells from different species to light-dependent CO2 fixation in the presence of monuron may also be involved in urea herbicide selectivity and undoubtedly is due to the differential photosynthetic pathways present nn them. 相似文献
14.
A bacterial strain has been isolated from an enhanced thiocarbamate degradation soil and identified as Corynebacterium sp. The strain was capable of rapidly metabolizing EPTC in a liquid culture where the herbicide was the sole source of carbon. Evolution of high quantities of [14C]carbon dioxide was coupled with a rapid decline of [14C]EPTC in the medium; after 12 h incubation these accounted for, respectively, 60% and 0% of the recoverable radioactivity. Radioactivity in the polar extract increased gradually up to 20% after 6 h of incubation and then declined slowly. TLC analysis and identification based on comparison to reference compounds showed that the polar extract consisted of EPTC sulfoxide and two conjugates, EPTC-GSH and EPTC-cysteine (1·8%, 3·4%, and 16%, respectively). Piperonyl butoxide and tetcyclasis, but not tridiphane, were found to be effective inhibitors of EPTC metabolism in the bacterial culture, suggesting that the breakdown of EPTC might be carried out by a cytochrome P-450 monooxygenase-type activity. The thiocarbamate extender, dietholate, also strongly inhibited the metabolism of EPTC in bacterial culture. Based on these results it was postulated that the bacteria metabolize EPTC mainly by hydroxylation of the α-propyl carbon finally to release [14C]carbon dioxide, while EPTC sulfoxidation appears to be a minor route. 相似文献
15.
Standing water from carbofuran-treated Azolla plots showing accelerated degradation was further enriched by five repeated transfers to carbofuran-supplemented mineral salts medium. This enrichment culture developed from standing water of carbofuran-treated Azolla plot can utilise carbofuran as sole source of carbon and nitrogen. The enrichment culture was able to hydrolyse nearly 100% of [ring-14C]carbofuran to carbofuran phenol in five days, which accumulated in the medium, while the carbamate side-chain in [carbonyl-14C]carbofuran was readily mineralized to [14C]carbon dioxide. Enrichment culture was able to degrade carbofuran up to 1000 µg ml−1 levels in mineral salts medium with ease. © 1999 Society of Chemical Industry 相似文献
16.
Buffers and leaf discs of mature tobacco (Nicotiana tabacum L.) were utilized to study [14C]-ethylene and 14CO2 evolution from radiolabeled ethephon, (2-chloroethyl)phosphonic acid. Metabolic fate of [14C]ethephon in leaf discs was investigated by use of thin-layer chromatography, high-voltage paper electrophoresis, autoradiography, and liquid scintillation spectroscopy. The evolution of labeled ethylene generally increased with increasing buffer pH, buffer volume, and dosage of [14C]ethephon. [14C]Ethylene was evolved, increasingly with time, from [14C]ethephon either added to the buffer or applied to leaf discs. The rate of [14C]ethylene evolution was maximum during the first day and leveled off on the fourth day. More than 50% of the total [14C]ethylene evolution over a 96-hr period was recovered during the first 24 hr after [14C]ethephon application. No 14CO2 was evolved when [14C]ethephon was degraded in the presence of buffer or leaf discs. Only ethephon itself, and no detectable metabolite thereof, was discovered in the methanolic extract of the leaf disc tissue. An insignificant amount of 14C activity (approximately 2% of the extracted 14C) was detected in the residue. By means of gas chromatography, it was confirmed that in buffers and tobacco leaf tissue ethephon breaks down to release ethylene but not CO2. 相似文献
17.
The breakdown of the herbicide benzoylprop ethyl [SUFFIX, ethyl N-benzoyl-N-(3,4-dichlorophenyl)-2-aminopropionate] has been examined in wheat, oat, and barley seedlings after application of 14C-labeled herbicide to the foliage.Within 15 days of the application the route and rate of the breakdown were similar in the plants of all three species. Some of the herbicide was present in the plants in a complexed form which could be extracted from the plant with organic solvents and converted back into the herbicide on treatment with hot acid. Evidence was obtained for hydrolysis of the herbicide in the plant to give its des-ethyl analog which conjugated with plant sugars. There was some evidence for a small degree of degradation of benzoylprop ethyl by debenzoylation to give products which also conjugated or complexed.There was no evidence for the formation of 3,4-dichloroaniline in the plants. 相似文献
18.
R.E. Wilkinson 《Pesticide biochemistry and physiology》1985,24(1):103-111
Vernolate (0, 8, 16, 31, 62, 125.0, or 250.0 ppbw) incorporated into sand inhibited the growth of wheat (Triticum aestivum L. cv Holley) at 125.0 ppbw. These growth inhibition and morphological responses were virtually identical to wheat response to EPTC at 125 ppbw. 14C from vernolate (carbonyl labeled) (125.0 ppbw) was absorbed into wheat seedlings at approximately 1.8 μM on the presumption that the 14C present was [14C]vernolate. Since the response of wheat to the thiocarbamate herbicides resembles a gibberellic acid (GA) deficiency and cell enlargement requires the presence of functional plasmalemmas and tonoplasts, the question of membrane disruption by excessive concentrations of thiocarbamate herbicides and potential reversal thereof by GA3 was studied by measuring the efflux of K+, Na+, and Mg2+. GA3 (0.003 μM) stimulated lettuce leaf disc growth in diameter and fresh weight. This GA-stimulated increase in size and weight was reversed by 1 mM EPTC. Betacyanin efflux from beet leaf tonoplasts was increased by 1 mM EPTC and this efflux was not reversed by exogenous GA3 (0.3 μM). This influence by supraoptimal EPTC concentrations was shown to be via membrane disruption, which obviated any possible GA influence by eliminating the functionality of the membranes requisite to the development of a GA response. It is concluded that viable mode-of-action studies must measure physiological responses consistent with the symptomology of herbicide responses normally observed with each herbicide at field concentrations. 相似文献
19.
The metabolism of [ 14 C]-4-nitrophenol and [ 14 C]-3,4-dichloroaniline (the xenobiotics are degradation products of parathion and propanil, respectively) was studied in cell suspension cultures of carrot (Daucus carota L.). 4-Nitrophenol was transformed almost quantitatively to water-soluble conjugates with minor amounts of non-extractable residues. The conjugates identified were 1-(O-β-D-glucopyranosyl)-4-nitrobenzene and 1-(6′-O-malonyl-O-β-D-glucopyranosyl)-4-nitrobenzene. In addition, two unidentified metabolites were observed, possibly a disaccharide and another malonylated glycoside of 4-nitrophenol. Time-course studies demonstrated that 4-nitrophenol was rapidly taken up and conjugated; all metabolites remained associated with the cells rather than nutrient medium. 3,4-Dichloroaniline was transformed quantitatively to water-soluble conjugates and bound residues (3.6%). The water-soluble metabolites were identified as 6′-O-malonyl-N-(β-D-glucopyranosyl)-3,4-dichloroaniline, N-(β-D-glucopyranosyl)-3,4-dichloroaniline and N-malonyl-3,4-dichloroaniline. A time-course study showed that the glucosides were formed initially, then decreased, possibly due to hydrolysis. This decrease was paralleled by an increase of the main metabolite, N-malonyl-3,4-dichloroaniline, which was predominantly recovered from the medium. 相似文献
20.
L. Müller W. Mittelstaedt J. Pfitzner F. Führ H.J. Jarczyk 《Pesticide biochemistry and physiology》1983,19(3):254-261
In a lysimeter experiment, [3-14C]metamitron was sprayed in a preemergence treatment of sugar beets, corresponding to approx 4.9 kg metamitron (7 kg Goltix)/ha. After 6 months, the beets contained metamitron equivalents amounting to 0.1 mg/kg fresh wt, calculated on the basis of the specific radioactivity of the [3-14C]metamitron employed. Radioactivity was also detected in the pure sugar isolates. The 14C activity represented approx 0.2 mg metamitron equivalent/kg pure sugar. Since the specific radioactivities of the sugar fractions were too low to employ physicochemical methods, a microbial degradation was used to investigate whether the radiocarbon was incorporated in the sucrose molecule. Microorganisms (Proteus vulgaris) degraded [U-14C] sucrose and the sugar isolates at the same 14CO2 release rates under strictly controlled experimental conditions. This result indicates that about one fourth of the carbon from the C-3 position of the triazine ring of the metamitron, found in the sugar beets at harvest time, is partly being used as a substrate in the production of sucrose possibly via assimilation of mineralized 14CO2. 相似文献