scholarly journals Characterization of S-Triazine Herbicide Metabolism by a Nocardioides sp. Isolated from Agricultural Soils

2000 ◽  
Vol 66 (8) ◽  
pp. 3134-3141 ◽  
Author(s):  
Edward Topp ◽  
Walter M. Mulbry ◽  
Hong Zhu ◽  
Sarah M. Nour ◽  
Diane Cuppels
Keyword(s):  
Agricultural Soils ◽  
Sole Source ◽  
Bacterial Strains ◽  
Corn Production ◽  
Whole Cells ◽  
Carbon And Nitrogen ◽  
Cell Extracts ◽  
Hydrolytic Reaction ◽  
Central Canada

ABSTRACT Atrazine, a herbicide widely used in corn production, is a frequently detected groundwater contaminant. Nine gram-positive bacterial strains able to use this herbicide as a sole source of nitrogen were isolated from four farms in central Canada. The strains were divided into two groups based on repetitive extragenic palindromic (rep)-PCR genomic fingerprinting with ERIC and BOXA1R primers. Based on 16S ribosomal DNA sequence analysis, both groups were identified as Nocardioides sp. strains. None of the isolates mineralized [ring-U-14C]atrazine. There was no hybridization to genomic DNA from these strains usingatzABC cloned from Pseudomonas sp. strain ADP or trzA cloned from Rhodococcus corallinus. S-Triazine degradation was studied in detail inNocardioides sp. strain C190. Oxygen was not required for atrazine degradation by whole cells or cell extracts. Based on high-pressure liquid chromatography and mass spectrometric analyses of products formed from atrazine in incubations of whole cells with H2 18O, sequential hydrolytic reactions converted atrazine to hydroxyatrazine and then to the end productN-ethylammelide. Isopropylamine, the putative product of the second hydrolytic reaction, supported growth as the sole carbon and nitrogen source. The triazine hydrolase from strain C190 was isolated and purified and found to have a Km for atrazine of 25 μM and a V max of 31 μmol/min/mg of protein. The subunit molecular mass of the protein was 52 kDa. Atrazine hydrolysis was not inhibited by 500 μM EDTA but was inhibited by 100 μM Mg, Cu, Co, or Zn. Whole cells and purified triazine hydrolase converted a range of chlorine or methylthio-substituted herbicides to the corresponding hydroxy derivatives. In summary, an atrazine-metabolizingNocardioides sp. widely distributed in agricultural soils degrades a range of s-triazine herbicides by means of a novel s-triazine hydrolase.

scholarly journals Aerobic Degradation of Dinitrotoluenes and Pathway for Bacterial Degradation of 2,6-Dinitrotoluene

2000 ◽  
Vol 66 (5) ◽  
pp. 2139-2147 ◽  
Author(s):  
Shirley F. Nishino ◽  
George C. Paoli ◽  
Jim C. Spain
Keyword(s):  
Burkholderia Cepacia ◽  
Dienoic Acid ◽  
Sole Source ◽  
Bacterial Degradation ◽  
Ring Cleavage ◽  
Bacterial Strains ◽  
Carbon And Nitrogen ◽  
Isolation And Characterization ◽  
Oxidative Pathway

ABSTRACT An oxidative pathway for the mineralization of 2,4-dinitrotoluene (2,4-DNT) by Burkholderia sp. strain DNT has been reported previously. We report here the isolation of additional strains with the ability to mineralize 2,4-DNT by the same pathway and the isolation and characterization of bacterial strains that mineralize 2,6-dinitrotoluene (2,6-DNT) by a different pathway.Burkholderia cepacia strain JS850 andHydrogenophaga palleronii strain JS863 grew on 2,6-DNT as the sole source of carbon and nitrogen. The initial steps in the pathway for degradation of 2,6-DNT were determined by simultaneous induction, enzyme assays, and identification of metabolites through mass spectroscopy and nuclear magnetic resonance. 2,6-DNT was converted to 3-methyl-4-nitrocatechol by a dioxygenation reaction accompanied by the release of nitrite. 3-Methyl-4-nitrocatechol was the substrate for extradiol ring cleavage yielding 2-hydroxy-5-nitro-6-oxohepta-2,4-dienoic acid, which was converted to 2-hydroxy-5-nitropenta-2,4-dienoic acid. 2,4-DNT-degrading strains also converted 2,6-DNT to 3-methyl-4-nitrocatechol but did not metabolize the 3-methyl-4-nitrocatechol. Although 2,6-DNT prevented the degradation of 2,4-DNT by 2,4-DNT-degrading strains, the effect was not the result of inhibition of 2,4-DNT dioxygenase by 2,6-DNT or of 4-methyl-5-nitrocatechol monooxygenase by 3-methyl-4-nitrocatechol.

Characterization of Muscle Sarcoplasmic and Myofibrillar Protein Hydrolysis Caused by Lactobacillus plantarum

1999 ◽  
Vol 65 (8) ◽  
pp. 3540-3546 ◽  
Author(s):  
Silvina Fadda ◽  
Yolanda Sanz ◽  
Graciela Vignolo ◽  
M.-Concepción Aristoy ◽  
Guillermo Oliver ◽  
...  
Keyword(s):  
Lactobacillus Plantarum ◽  
Myofibrillar Protein ◽  
Myofibrillar Proteins ◽  
Muscle Proteins ◽  
Whole Cells ◽  
Sarcoplasmic Proteins ◽  
Cell Extracts ◽  
Hydrophobic Nature ◽  
Hydrolysis Of

ABSTRACT Strains of Lactobacillus plantarum originally isolated from sausages were screened for proteinase and aminopeptidase activities toward synthetic substrates; on the basis of that screening,L. plantarum CRL 681 was selected for further assays on muscle proteins. The activities of whole cells, cell extracts (CE), and a combination of both on sarcoplasmic and myofibrillar protein extracts were determined by protein, peptide, and free-amino-acid analyses. Proteinase from whole cells initiated the hydrolysis of sarcoplasmic proteins. The addition of CE intensified the proteolysis. Whole cells generated hydrophilic peptides from both sarcoplasmic and myofibrillar proteins. Other peptides of a hydrophobic nature resulted from the combination of whole cells and CE. The action of both enzymatic sources on myofibrillar proteins caused maximal increases in lysine, arginine, and leucine, while the action of those on sarcoplasmic proteins mainly released alanine. In general, pronounced hydrolysis of muscle proteins required enzyme activities from whole cells in addition to those supplied by CE.

scholarly journals Isolation, Biochemical and Genomic Characterization of Glyphosate Tolerant Bacteria to Perform Microbe-Assisted Phytoremediation

2021 ◽  
Vol 11 ◽  
Author(s):  
Francisco Massot ◽  
Panagiotis Gkorezis ◽  
Jonathan Van Hamme ◽  
Damian Marino ◽  
Bojana Spirovic Trifunovic ◽  
...  
Keyword(s):  
Plant Growth ◽  
Plant Growth Promotion ◽  
Large Scale ◽  
Agricultural Soils ◽  
Growth Promotion ◽  
Sole Source ◽  
Bacterial Strains ◽  
Positive Effects ◽  
Assisted Phytoremediation

The large-scale use of the herbicide glyphosate leads to growing ecotoxicological and human health concerns. Microbe-assisted phytoremediation arises as a good option to remove, contain, or degrade glyphosate from soils and waterbodies, and thus avoid further spreading to non-target areas. To achieve this, availability of plant-colonizing, glyphosate-tolerant and -degrading strains is required and at the same time, it must be linked to plant-microorganism interaction studies focusing on a substantive ability to colonize the roots and degrade or transform the herbicide. In this work, we isolated bacteria from a chronically glyphosate-exposed site in Argentina, evaluated their glyphosate tolerance using the minimum inhibitory concentration assay, their in vitro degradation potential, their plant growth-promotion traits, and performed whole genome sequencing to gain insight into the application of a phytoremediation strategy to remediate glyphosate contaminated agronomic soils. Twenty-four soil and root-associated bacterial strains were isolated. Sixteen could grow using glyphosate as the sole source of phosphorous. As shown in MIC assay, some strains tolerated up to 10000 mg kg–1 of glyphosate. Most of them also demonstrated a diverse spectrum of in vitro plant growth-promotion traits, confirmed in their genome sequences. Two representative isolates were studied for their root colonization. An isolate of Ochrobactrum haematophilum exhibited different colonization patterns in the rhizoplane compared to an isolate of Rhizobium sp. Both strains were able to metabolize almost 50% of the original glyphosate concentration of 50 mg l–1 in 9 days. In a microcosms experiment with Lotus corniculatus L, O. haematophilum performed better than Rhizobium, with 97% of glyphosate transformed after 20 days. The results suggest that L. corniculatus in combination with to O. haematophilum can be adopted for phytoremediation of glyphosate on agricultural soils. An effective strategy is presented of linking the experimental data from the isolation of tolerant bacteria with performing plant-bacteria interaction tests to demonstrate positive effects on the removal of glyphosate from soils.

scholarly journals The isolation and identification of 6-hydroxycyclohepta-1,4-dione as a novel intermediate in the bacterial degradation of atropine

1993 ◽  
Vol 293 (1) ◽  
pp. 115-118 ◽  
Author(s):  
B A Bartholomew ◽  
M J Smith ◽  
M T Long ◽  
P J Darcy ◽  
P W Trudgill ◽  
...  
Keyword(s):  
Growth Medium ◽  
Sole Source ◽  
Bacterial Degradation ◽  
Diauxic Growth ◽  
Growth Substrate ◽  
Isolation And Identification ◽  
Carbon And Nitrogen ◽  
Tropic Acid ◽  
Cell Extracts

Growth of Pseudomonas AT3 on the alkaloid atropine as its sole source of carbon and nitrogen is nitrogen-limited and proceeds by degradation of the tropic acid part of the molecule, with the metabolism of the tropine being limited to the point of release of its nitrogen. A nitrogen-free compound accumulated in the growth medium and was isolated and identified as 6-hydroxycyclohepta-1,4-dione. This novel compound is proposed as an intermediate in tropine metabolism. It served as a growth substrate for the organism and was also the substrate for an NAD(+)-linked dehydrogenase present in cell extracts. The enzyme was induced during the tropine phase of diauxic growth on atropine or during growth on tropine alone.

scholarly journals Characterization of an Atrazine-DegradingPseudaminobacter sp. Isolated from Canadian and French Agricultural Soils

2000 ◽  
Vol 66 (7) ◽  
pp. 2773-2782 ◽  
Author(s):  
Edward Topp ◽  
Hong Zhu ◽  
Sarah M. Nour ◽  
Sabine Houot ◽  
Melanie Lewis ◽  
...  
Keyword(s):  
Trifolium Pratense ◽  
Agricultural Soils ◽  
Red Clover ◽  
Metabolite Identification ◽  
Sole Source ◽  
Degradation Pathway ◽  
Triazine Herbicides ◽  
Bacterial Strains ◽  
16S Rrna Sequence ◽  
Atrazine Degradation

ABSTRACT Atrazine, a herbicide widely used in corn production, is a frequently detected groundwater contaminant. Fourteen bacterial strains able to use this herbicide as a sole source of nitrogen were isolated from soils obtained from two farms in Canada and two farms in France. These strains were indistinguishable from each other based on repetitive extragenic palindromic PCR genomic fingerprinting performed with primers ERIC1R, ERIC2, and BOXA1R. Based on 16S rRNA sequence analysis of one representative isolate, strain C147, the isolates belong to the genusPseudaminobacter in the family Rhizobiaceae. Strain C147 did not form nodules on the legumes alfalfa (Medicago sativa L.), birdsfoot trefoil (Lotus corniculatusL.), red clover (Trifolium pratense L.), chickpea (Cicer arietinum L.), and soybean (Glycine maxL.). A number of chloro-substituted s-triazine herbicides were degraded, but methylthio-substituted s-triazine herbicides were not degraded. Based on metabolite identification data, the fact that oxygen was not required, and hybridization of genomic DNA to the atzABC genes, atrazine degradation occurred via a series of hydrolytic reactions initiated by dechlorination and followed by dealkylation. Most strains could mineralize [ring-U-14C]atrazine, and those that could not mineralize atrazine lacked atzB or atzBC. The atzABC genes, which were plasmid borne in every atrazine-degrading isolate examined, were unstable and were not always clustered together on the same plasmid. Loss of atzBwas accompanied by loss of a copy of IS1071. Our results indicate that an atrazine-degradingPseudaminobacter sp. with remarkably little diversity is widely distributed in agricultural soils and that genes of the atrazine degradation pathway carried by independent isolates of this organism are not clustered, can be independently lost, and may be associated with a catabolic transposon. We propose that the widespread distribution of the atrazine-degradingPseudaminobacter sp. in agricultural soils exposed to atrazine is due to the characteristic ability of this organism to utilize alkylamines, and therefore atrazine, as sole sources of carbon when the atzABC genes are acquired.

scholarly journals Characterization of the Polyurethanolytic Activity of Two Alicycliphilus sp. Strains Able To Degrade Polyurethane and N-Methylpyrrolidone

2007 ◽  
Vol 73 (19) ◽  
pp. 6214-6223 ◽  
Author(s):  
Alejandro Oceguera-Cervantes ◽  
Agustín Carrillo-García ◽  
Néstor López ◽  
Sandra Bolaños-Nuñez ◽  
M. Javier Cruz-Gómez ◽  
...  
Keyword(s):  
Esterase Activity ◽  
Maximum Growth ◽  
Maximal Activity ◽  
Gas Chromatography Mass Spectrometry ◽  
Rrna Gene ◽  
Bacterial Strains ◽  
Carbon And Nitrogen ◽  
Gene Sequence Analysis ◽  
Hyperbolic Behavior

ABSTRACT Two bacterial strains (BQ1 and BQ8) were isolated from decomposed soft foam. These were selected for their capacity to grow in a minimal medium (MM) supplemented with a commercial surface-coating polyurethane (PU) (Hydroform) as the carbon source (MM-PUh). Both bacterial strains were identified as Alicycliphilus sp. by comparative 16S rRNA gene sequence analysis. Growth in MM-PUh showed hyperbolic behavior, with BQ1 producing higher maximum growth (17.8 ± 0.6 mg·ml−1) than BQ8 (14.0 ± 0.6 mg·ml−1) after 100 h of culture. Nuclear magnetic resonance, Fourier transform infrared (IR) spectroscopy, and gas chromatography-mass spectrometry analyses of Hydroform showed that it was a polyester PU type which also contained N-methylpyrrolidone (NMP) as an additive. Alicycliphilus sp. utilizes NMP during the first stage of growth and was able to use it as the sole carbon and nitrogen source, with calculated K s values of about 8 mg·ml−1. Enzymatic activities related to PU degradation (esterase, protease, and urease activities) were tested by using differential media and activity assays in cell-free supernatants of bacterial cultures in MM-PUh. Induction of esterase activity in inoculated MM-PUh, but not that of protease or urease activities, was observed at 12 h of culture. Esterase activity reached its maximum at 18 h and was maintained at 50% of its maximal activity until the end of the analysis (120 h). The capacity of Alicycliphilus sp. to degrade PU was demonstrated by changes in the PU IR spectrum and by the numerous holes produced in solid PU observed by scanning electron microscopy after bacterial culture. Changes in the PU IR spectra indicate that an esterase activity is involved in PU degradation.

Isolation, Identification, and Characterization of Lambda-Cyhalothrin Pesticide Degrading Bacterium ZC-5

2016 ◽  
Vol 723 ◽  
pp. 628-632
Author(s):  
Rong Hu Zhang ◽  
Zhen Hua Zhou ◽  
Jian Cheng Feng
Keyword(s):  
Sole Source ◽  
Achromobacter Xylosoxidans ◽  
Logarithmic Phase ◽  
Aeration Tank ◽  
16S Rdna Sequence ◽  
Carbon And Nitrogen ◽  
Degrading Bacterium ◽  
Lambda Cyhalothrin ◽  
Novel Strategy

A highly efficient lambda-cyhalothrin-degrading bacterium, designated as strain ZC-5, was isolated from the activated sludge of a sewage aeration tank in a pesticide factory by enrichment acclimation and the streak plate method. Strain ZC-5 can grow on minimal medium with lambda-cyhalothrin as the sole source of carbon and nitrogen. After cultivation for 6 h to 24 h, the biomass of the bacterial strain significantly increased at the logarithmic phase. By contrast, the concentration of lambda-cyhalothrin rapidly decreased. The residual lambda-cyhalothrin presented a concentration of 250 mg/L and a degradation rate of 50%. Gas chromatography revealed that this strain can degrade 87.1% lambda-cyhalothrin (500 mg/L) in the culture within 2 days. Morphological analysis showed the Gram-negative strain as short rods. Physiological and biochemical characterizations, as well as phylogenetic analysis of the 16S rDNA sequence identified the bacterium to be an Achromobacter xylosoxidans strain. Results showed that this strain can provide a novel strategy to biodegrade the pesticide lambda-cyhalothrin.

Characterization of an inducible porter required for L-proline catabolism by Escherichia coli K12

1979 ◽  
Vol 57 (10) ◽  
pp. 1191-1199 ◽  
Author(s):  
Janet M. Wood ◽  
David Zadworny
Keyword(s):  
Escherichia Coli ◽  
Catabolite Repression ◽  
Sole Source ◽  
Proline Oxidase ◽  
Transport Reaction ◽  
Carbon And Nitrogen ◽  
Escherichia Coli K12 ◽  
Proline Catabolism ◽  
Uptake Activity

L-Proline can serve as sole source of carbon and nitrogen for the growth of Escherichia coli K12 and other Enterobacteria. L-Proline uptake and L-proline oxidase are suoject both to catabolite repression and to specific induction by L-proline or glycyl-L-proline, although their regulation is not strictly coordinate. A strain defective for L-proline uptake due to a lesion at the locus putP does not show elevated uptake activity either on relief of catabolite repression or when grown on glycyl-L-proline as nitrogen source. The apparent Km for L-proline uptake decreases up to 14-fold as uptake Vm increases when cells are induced for both L-proline uptake and L-proline oxidase; cells with increased uptake activity, alone, do not show an altered Km. Although L-proline is metabolized during the uptake measurements, uptake is always active. The observed variations in uptake Km are unlikely to result from the escape of radioactive L-proline metabolites or from reversal of the transport reaction during the uptake measurements. We conclude that the L-proline porter encoded in putP is responsible for 80 to 90% of the constitutive and for the inducible L-proline uptake activity of wild-type bacteria. Although this porter is amplified in cells induced for L-proline catabolism, the observed values for uptake Vm may not be taken as a direct indicator of porter concentration.

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