Microbial degradation of [14C]polystyrene and 1,3-diphenylbutane

1978 ◽  
Vol 24 (7) ◽  
pp. 798-803 ◽  
Author(s):  
M. Sielicki ◽  
D. D. Focht ◽  
J. P. Martin

Microbial degradation of [β-14C]polystyrene and 1,3-diphenylbutane, a compound structurally representing the smallest repeating unit of styrene (dimer), was investigated in soil and liquid enrichment cultures. Degradation rates in soil, as determined by 14CO2 evolution from applied [14C]polystyrene, varied from 1.5 to 3.0% for a 4-month period. Although relatively low, these percentages were 15 to 30 times greater than values previously reported. Enrichment cultures, containing 1,3-diphenylbutane as the only carbon source, were used to determine the mechanisms of microbial oxidation of the polymer chain ends. Metabolism of 1,3-diphenylbutane appeared to involve the attack by a monooxygenase to form 2-phenyl-4-hydroxyphenylbutane followed by a further oxidation and subsequent fission of the benzene ring to yield 4-phenylvaleric acid and an unidentified 5-carbon fragment via the classic meta-fission pathway. Phenylacetic acid was probably formed from 4-phenylvaleric acid by subsequent β-oxidation of the side chain, methyl-oxidation, and decarboxylation. An initial examination of the population of microorganisms in the diphenylbutane enrichment cultures indicated that these oxidative reactions are carried out by common soil microorganisms of the genera Bacillus, Pseudomonas, Micrococcus, and Nocardia.

1933 ◽  
Vol 8 (5) ◽  
pp. 447-449 ◽  
Author(s):  
Steward Basterfield ◽  
James W. Tomecko

The ionization constants of p-nitrophenylacetic and phenylmalonic acids have been determined from conductivity data. The value of K for p-nitrophenylacetic acid at 25 °C. is 1.04 × 10−4, about twice that of phenylacetic acid. The nitro group in the nucleus has not as powerful an effect on the ionization when the COOH group is in the side chain as it has when both nitro group and COOH are in the nucleus. K for p-nitrobenzoic acid is six times as great as K for benzoic acid. K for phenylmalonic acid is 2. 77 × 10−3 as compared with 1.6 × 10−3 for malonic acid.


2018 ◽  
Vol 187 ◽  
pp. 243-259 ◽  
Author(s):  
Mohammad-Saeid Jami ◽  
Juan-Francisco Martín ◽  
Carlos Barreiro ◽  
Rebeca Domínguez-Santos ◽  
María-Fernanda Vasco-Cárdenas ◽  
...  
Keyword(s):  

1981 ◽  
Vol 15 (9) ◽  
pp. 1125-1127 ◽  
Author(s):  
E DAVIS ◽  
H MURRAY ◽  
J LIEHR ◽  
E POWERS

1984 ◽  
Vol 30 (12) ◽  
pp. 1458-1466 ◽  
Author(s):  
B. S. Rajagopal ◽  
V. R. Rao ◽  
G. Nagendrappa ◽  
N. Sethunathan

Metabolism of side chain and ring 14C-labelled carbaryl and carbofuran in a mineral salts medium by soil-enrichment cultures and a Bacillus sp. was studied. A change in the substrate of the medium from carbaryl to carbofuran led to a marked shift in the dominant bacterium from Bacillus sp. to Arthrobacter sp. although carbaryl-enrichment culture was the primary inoculum in both media. Hydrolysis was the major route of microbial degradation of both carbamate insecticides. During carbaryl degradation by enrichment cultures and Bacillus sp., 1-naphthol and 1,4-naphthoquinone accumulated in the medium. Of the three metabolites formed from carbofuran, 3-hydroxycarbofuran and 3-ketocarbofuran were further metabolized rapidly, while carbofuran phenol was resistant to further degradation. Evolution of 14CO2 and other gaseous 14C-labelled products from both side chain and ring labels was negligible. This and slow degradation of the hydrolysis products led to significant accumulation of 14C in the medium even after prolonged incubation.


Weed Science ◽  
1972 ◽  
Vol 20 (4) ◽  
pp. 344-347 ◽  
Author(s):  
H. D. Skipper ◽  
V. V. Volk

Microbial degradation of 2-chloro-4-(ethylamino)-6-(isopropylamino)-s-triazine (atrazine) and 2-hydroxy-4-(ethylamino)-6-(isopropylamino)-s-triazine (hydroxyatrazine) was investigated in three Oregon soils. Hydrolysis of atrazine was determined by the presence of14C-hydroxyatrazine in methanol extracts. Respired14CO2from the14C-ethyl side chain of atrazine represented less than 10% of the added14C in the soils after 28 days. Degradation was dependent on soil type, atrazine concentration, and moisture content. The isopropyl and ring constituents of atrazine were subject to minimal attack. The hydroxyatrazine ring was attacked more readily than the atrazine ring. Hydroxyatrazine accounted for approximately 10% of the extracted14C from14C-atrazine-treated Parkdale-A, Parkdale-C, and Coker soils and 40% from the Woodburn soil. Hydrolysis was the dominant pathway of detoxification in the Woodburn soil, whereas detoxification of atrazine in Parkdale-A, Parkdale-C, and Coker soils was a combination of chemical hydrolysis and slow microbial degradation byN-dealkylation of the ethyl side chain constituent.


Weed Science ◽  
1969 ◽  
Vol 17 (1) ◽  
pp. 52-55 ◽  
Author(s):  
Don S. Murray ◽  
Walter L. Rieck ◽  
J. Q. Lynd

Phytotoxicity of five substituted urea herbicides 3-(3,4-dichlorophenyl)-1,1-dimethylurea (diuron), 3-(p-chlorophenyl)-1,1-dimethylurea (monuron), 3-phenyl-1,1-dimethylurea (fenuron), 3-hexahydro-4,7-methanoindan-5-yl) −1,1-dimethylurea (norea), and 3-(m-trifluoromethylphenyl)-1,1-dimethylurea (fluometuron) at 0, 10, 100, and 1000 ppm were determined in factorial combination at four urea nitrogen levels of 0, 45, 450, and 900 ppm with three Aspergilli: A. niger, A. sydowi, and A. tamarii. Response interactions were apparent, with all three fungi most tolerant for fenuron and least for diuron. Apparent tolerance order of the three intermediates were: A. niger, norea > fluometuron > monuron; A. sydowi, fluometuron > monuron > norea; and A. tamarii, fluometuron > norea > monuron. Oat (Avena sativa L.) bioassay for residual herbicide toxicity indicated significant differences in herbicide degradation rates between these three fungi at 5, 10, and 20 ppm in Eufaula sand. Diuron was more rapidly degraded than monuron at these levels with fluometuron and norea somewhat intermediate. A. niger was most effective in degradation of these herbicides with A. tamarii greater than A. sydowi. High nitrogen levels in soil organic matter amendment generally favored increased rates of urea herbicide degradation.


1981 ◽  
Vol 193 (1) ◽  
pp. 325-337 ◽  
Author(s):  
T P Karpetsky ◽  
K K Shriver ◽  
C C Levy

Segments of poly(A) at the 3′-termini of 5 S rRNA inhibit the activities of ribonucleases from Citrobacter, Enterobacter, bovine pancreas, human spleen and human plasma. Certain polyamines, or compounds containing polyamine substructures, mediate reversal of this inhibition. Effective compounds contain three amino groups, at least two of which are charged and are separated from the others by no less than three carbon atoms. Spermidine and 9-aminoacridines, which contain substituted propyl- or butylamino moieties at the 9-amino position and which bear two positive charges per molecule, are efficacious at low concentrations (5 microM). A decrease in effectiveness is associated with the removal of one aromatic ring from the 9-aminoacridines. However, the resulting 4-aminoquinolines, unlike the acridines, do not inhibit enzyme activity when present in concentrations above 30 microM. Relocating the diamino side chain from the 4- to the 8-position of the quinoline nucleus causes a decrease in charge density to +1, with the result that such compounds are ineffective. The orders of polyamine efficacy of reversal of inhibition were similar for enzymes from Citrobacter, bovine pancreas, and human plasma, and paralleled the order of binding of polyamines to either poly(A) or 5 S rRNA. This was not the case with Enterobacter and human spleen RNAases, indicating that the identity of the most effective polyamines depends on the RNAase studied. The combination of variable 3′-terminal poly(A) segment length and polyamine identity and concentration constitutes a system by which RNAase activities, and, therefore, substrate-degradation rates, may be easily varied.


1970 ◽  
Vol 117 (3) ◽  
pp. 593-600 ◽  
Author(s):  
G. R. Whistance ◽  
D. R. Threlfall

1. By means of 14C tracer experiments and isotope competition experiments the roles of d-tyrosine, p-hydroxyphenylpyruvic acid, p-hydroxyphenylacetic acid, phenylacetic acid, homogentisic acid and homoarbutin (2-methylquinol 4-β-d-glucoside) in the biosynthesis of plastoquinones, tocopherols and α-tocopherolquinone by maize shoots was investigated. It was established that d-tyrosine, p-hydroxyphenylpyruvic acid and homogentisic acid can all be utilized for this purpose, whereas p-hydroxyphenylacetic acid, phenylacetic acid and homoarbutin cannot. Studies on the mode of incorporation of d-tyrosine, p-hydroxyphenylpyruvic acid and homogentisic acid showed that their nuclear carbon atoms and the side-chain carbon atom adjacent to the nucleus give rise (as a C6-C1 unit) to the p-benzoquinone rings and nuclear methyl groups (one in each case) of plastoquinone-9 and α-tocopherolquinone and the aromatic nuclei and nuclear methyl groups (one in each case) of γ-tocopherol and α-tocopherol. 2. By using [14C]-homogentisic acid it has been shown that homogentisic acid is also a precursor of plastoquinone, tocopherols and α-tocopherolquinone in the higher plants Lactuca sativa and Rumex sanguineus, the green algae Chlorella pyrenoidosa and Euglena gracilis and the blue–green alga Anacystis nidulans.


1969 ◽  
Vol 24 (5) ◽  
pp. 569-574 ◽  
Author(s):  
L. Jaenicke ◽  
Ch. Molzberger ◽  
I. Schlie ◽  
R. Tschesche ◽  
K. Brandau ◽  
...  

Extracts of Mycobacterium smegmatis synthesise dihydro-pteroate and dihydro-folate from dihydro-pteridine-6-carbinol as well as from dihydro-neopterin and dihydro-neopterin-3′-phosphate. The 7-isomers of the pteridine precursors are neither substrates nor inhibitors of folate biosynthesis. Side-chain 14C-labelled dihydro-neopterin yields similarly labelled dihydro-folate. From the isotopic data it is concluded that a two-carbon fragment is split off the chain and that C-1′ of dihydroneopterin becomes the bridging methylene group between the pteridine and the p-aminobenzoyl moiety of the compound produced.


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