The Possible Role of Hydroxylation in the Detoxification of Atrazine in Mature Vetiver (Chrysopogon zizanioides Nash) Grown in Hydroponics

2005 ◽  
Vol 60 (5-6) ◽  
pp. 427-434 ◽  
Author(s):  
Sylvie Marcacci ◽  
Muriel Raveton ◽  
Patrick Ravanel ◽  
Jean-Paul Schwitzguébel
Keyword(s):  
Cytochromes P450 ◽  
Resistance Mechanism ◽  
Uv Spectra ◽  
Chrysopogon Zizanioides ◽  
Retention Factors ◽  
Glutathione S Transferases ◽  
Layer Chromatography ◽  
Major Metabolic Pathway

The resistance mechanism of vetiver (Chrysopogon zizanioides) to atrazine was investigated to evaluate its potential for phytoremediation of environment contaminated with the herbicide. Plants known to metabolise atrazine rely on hydroxylation mediated by benzoxazinones, conjugation catalyzed by glutathione-S-transferases and dealkylation probably mediated by cytochromes P450. All three possibilities were explored in mature vetiver grown in hydroponics during this research project. Here we report on the chemical role of benzoxazinones in the transformation of atrazine.Fresh vetiver roots and leaves were cut to extract and study their content in benzoxazinones known to hydroxylate atrazine, such as 2,4-dihydroxy-2H-1,4-benzoxazin-3(4H)- one (DIBOA), 2,4-dihydroxy-7-methoxy-2H-1,4-benzoxazin-3(4H)-one (DIMBOA) and their mono- and di-glucosylated forms. Identification of benzoxazinones was performed by thin layer chromatography (TLC) and comparison of retention factors (Rf) and UV spectra with standards: although some products exhibited the same Rf as standards, UV spectra were different. Furthermore, in vitro hydroxylation of atrazine could not be detected in the presence of vetiver extracts. Finally, vetiver organs exposed to [14C]-atrazine did not produce any significant amount of hydroxylated products, such as hydroxyatrazine (HATR), hydroxydeethylatrazine (HDEA), and hydroxy-deisopropylatrazine (HDIA). Altogether, these metabolic features suggest that hydroxylation was not a major metabolic pathway of atrazine in vetiver.

Binding of 63Ni(II) to Ultrafiltrable Constituents of Rabbit Serum In Vivo and In Vitro

1975 ◽  
Vol 21 (4) ◽  
pp. 521-527 ◽  
Author(s):  
Noritake Asato ◽  
Maria van Soestbergen ◽  
F William Sunderman
Keyword(s):  
Rabbit Serum ◽  
Total Serum ◽  
In Vivo Experiments ◽  
The Mean ◽  
Layer Chromatography ◽  
In Vivo Administration ◽  
Mean Concentration

Abstract Binding of 63Ni(Il) to ultrafiltrable constituents of rabbit serum was studied (a) after in vitro incubation (2 h, 37 °C) of rabbit serum with 63NiCl2 (10-100 µmol/liter), and (b) at intervals (0.25-2 h) after in vivo administration of 63NiCl2 (40-160 µmol/kg body wt, i.v.). Serum ultrafiltrates were fractionated by thin-layer chromatography, and the separated compounds made visible by autoradiography and by ninhydrin staining. Several (≃5) ultrafiltrable 63Ni-complexes were demonstrable as distinct radiodense 63Ni-bands with chromatographic mobilities corresponding to those of ninhydrin-positive bands. Unbound 63Ni(II) was not detected in serum ultrafiltrates in either the in vitro or in vivo experiments. In sera (n = 10) incubated in vitro with 63Ni(II) (10 µmol/ liter), the mean percentage of ultrafiltrable 63Ni was 36% (range = 33-38) of total serum 63Ni. In contrast, in sera (n = 10) obtained 2 h after i.v. injection of 63Ni(II) (40 µmol/kg), the mean concentration of total serum 63Ni was 10.8 µmol/liter (range = 6-14), and the mean percentage of ultrafiltrable 63Ni was 15% (range = 9-21) of total serum 63Ni. The disparity between the percentages of ultrafiltrable 63Ni obtained in vitro and in vivo was obviated when the in vivo experiments were performed in rabbits bilaterally nephrectomized, with ligated common bile ducts. This investigation confirms the existence of several nickel receptors in serum ultrafiltrates and substantiates the role of ultrafiltrable complexes in the excretion of nickel.

scholarly journals Distinct Roles for Two CYP226 Family Cytochromes P450 in Abietane Diterpenoid Catabolism by Burkholderia xenovorans LB400

2007 ◽  
Vol 190 (5) ◽  
pp. 1575-1583 ◽  
Author(s):  
Daryl J. Smith ◽  
Marianna A. Patrauchan ◽  
Christine Florizone ◽  
Lindsay D. Eltis ◽  
William W. Mohn
Keyword(s):  
Cytochromes P450 ◽  
Degradation Pathway ◽  
Dehydroabietic Acid ◽  
Burkholderia Xenovorans ◽  
Substrate Removal ◽  
Burkholderia Xenovorans Lb400 ◽  
Abietane Diterpenoids ◽  
Insertion Mutants

ABSTRACT The 80-kb dit cluster of Burkholderia xenovorans LB400 encodes the catabolism of abietane diterpenoids. This cluster includes ditQ and ditU, predicted to encode cytochromes P450 (P450s) belonging to the poorly characterized CYP226A subfamily. Using proteomics, we identified 16 dit-encoded proteins that were significantly more abundant in LB400 cells grown on dehydroabietic acid (DhA) or abietic acid (AbA) than in succinate-grown cells. A key difference in the catabolism of DhA and AbA lies in the differential expression of the P450s; DitU was detected only in the AbA-grown cells, whereas DitQ was expressed both during growth on DhA and during growth on AbA. Analyses of insertion mutants showed that ditQ was required for growth on DhA, ditU was required for growth on AbA, and neither gene was required for growth on the central intermediate, 7-oxo-DhA. In cell suspension assays, patterns of substrate removal and metabolite accumulation confirmed the role of DitU in AbA transformation and the role of DitQ in DhA transformation. Spectral assays revealed that DitQ binds both DhA (dissociation constant, 0.98 ± 0.01 μM) and palustric acid. Finally, DitQ transformed DhA to 7-hydroxy-DhA in vitro. These results demonstrate the distinct roles of the P450s DitQ and DitU in the transformation of DhA and AbA, respectively, to 7-oxo-DhA in a convergent degradation pathway.

Angiotensin II binding sites in aortic endothelium of domestic fowl

1990 ◽  
Vol 258 (3) ◽  
pp. R777-R782 ◽  
Author(s):  
J. N. Stallone ◽  
H. Nishimura ◽  
A. Nasjletti
Keyword(s):  
Angiotensin Ii ◽  
Domestic Fowl ◽  
Angiotensin Receptors ◽  
Ang Ii ◽  
Aortic Endothelium ◽  
Specific Receptors ◽  
Layer Chromatography

In domestic fowl, angiotensin II (ANG II) produces a unique vasodepressor response in vivo and endothelium-dependent relaxation of aortic rings in vitro that appear to be a direct effect on vascular smooth muscle mediated through vascular angiotensin receptors. To explore the possible role of the endothelium in ANG II-induced vasodilation, ANG II binding to aortic membrane fractions and intact endothelium and prostaglandin (PG) production were examined in fowl aortas. 125I-[Ile5]ANG II binding by endothelium-intact aortic membrane fractions was consistently higher than binding by identically prepared endothelium-deleted membrane fractions at virtually all concentrations of ligand (10 pM-0.20 microM). Incubation of intact aortic rings with 125I-[Ile5]ANG II (0.50 nM) resulted in specific endothelial binding that increased linearly with time from 5.5 +/- 1.7 (SE) fmol/mg protein at 5 min to 13.7 +/- 1.8 at 30 min. Endothelial ANG II binding increased linearly with the dose of ligand, from 2.7 +/- 0.3 fmol/mg protein at 0.1 nM to 21.0 +/- 2.2 at 1.0 nM. Specific ANG II binding to aortic endothelium was competitively displaced 73 +/- 11% by unlabeled ANG II (0.1 microM) but not by bradykinin (0.1 microM). Incubation of intact aortic rings with [14C]arachidonic acid resulted in the formation of radioactive metabolites that comigrated in thin-layer chromatography with authentic PGE2 but not with 6-keto-PGF1 alpha. PGE2 production by aortic rings (44.4 +/- 4.5 ng.mg dry tissue-1.h-1) was not stimulated by addition of ANG II. These results suggest that specific receptors for ANG II exist in fowl aortic endothelium and that PGs are not involved in ANG II-induced vasodilation of the fowl aorta.

scholarly journals Immunopurified Small Nucleolar Ribonucleoprotein Particles Pseudouridylate rRNA Independently of Their Association with Phosphorylated Nopp140

2002 ◽  
Vol 22 (24) ◽  
pp. 8457-8466 ◽  
Author(s):  
Chen Wang ◽  
Charles C. Query ◽  
U. Thomas Meier
Keyword(s):  
Cajal Body ◽  
Small Nucleolar Rnas ◽  
Ribonucleoprotein Particle ◽  
Vitro Assay ◽  
Body Protein ◽  
Core Proteins ◽  
Layer Chromatography ◽  
Nucleolar Rnas

ABSTRACT The isomerization of up to 100 uridines to pseudouridines (Ψs) in eukaryotic rRNA is guided by a similar number of box H/ACA small nucleolar RNAs (snoRNAs), each forming a unique small nucleolar ribonucleoprotein particle (snoRNP) with the same four core proteins, NAP57 (also known as dyskerin or Cbf5p), GAR1, NHP2, and NOP10. Additionally, the nucleolar and Cajal body protein Nopp140 (Srp40p) associates with the snoRNPs. To understand the role of these factors in pseudouridylation, we established an in vitro assay system. Short site-specifically 32P-labeled rRNA substrates were incubated with subcellular fractions, and the conversion of uridine to Ψ was monitored by thin-layer chromatography after digestion to single nucleotides. Immunopurified box H/ACA core particles were sufficient for the reaction. SnoRNPs associated quantitatively and reversibly with Nopp140. However, pseudouridylation activity was independent of Nopp140, consistent with a chaperoning role for this highly phosphorylated protein. Although up to 14 bp between the snoRNA and rRNA were required for the in vitro reaction, rRNA pseudouridylation and release occurred in the absence of ATP and magnesium. These data suggest that substrate release takes place without RNA helicase activity but may be aided by the snoRNP core proteins.

scholarly journals 17,20β-P and cortisol are the main in vitro metabolites of 17-hydroxy-progesterone produced by spermiating testes of Micropogonias furnieri (Desmarest, 1823) (Perciformes: Sciaenidae)

2015 ◽  
Vol 13 (3) ◽  
pp. 613-624 ◽  
Author(s):  
Denise Vizziano Cantonnet ◽  
Magdalena Mateo ◽  
Andrés Alberro ◽  
Florencia Barrios ◽  
Alexis Fostier
Keyword(s):  
Steroid Production ◽  
White Croaker ◽  
Potential Mediator ◽  
Micropogonias Furnieri ◽  
Hydroxy Progesterone ◽  
Layer Chromatography ◽  
Clear Increase ◽  
Circulating Levels

The aim was to investigate the major C21 steroids produced by spermiating white croaker Micropogonias furnieri (Sciaenidae) in order to establish the potential mediator of gamete maturation in males of this species. The testes steroid production at the spawning season was identified incubating the 3H-17-hydroxy-4-pregnene-3,20-dione precursor through thin layer chromatography, high pressure liquid chromatography, enzymatic oxydation, acetylation and immunochemistry analyses. 17,20β-Dihydroxy-4-pregnen-3-one (17,20β-P) and 11β,17,21-Trihydroxy-4-pregnene-3,20-dione (cortisol) were the main metabolites produced. Contrary to what we expected, 17,20β,21-Trihydroxy-4-pregnen-3-one was not detected. Circulating levels of 17,20β-P were undetectable in immature testes and in those at the first spermatogenesis stages, while a clear increase was observed during the whole spermatogenesis and spermiation phases (from undetectable to 1047 pg mL-1). In vitro studies together with plasma detection suggest that 17,20β-P is a good steroid candidate involved in M. furnieri testes maturation. The role of cortisol during late phases of testes development needs further studies.

scholarly journals Phenobarbital Induction and Chemical Synergism Demonstrate the Role of UDP-Glucuronosyltransferases in Detoxification of Naphthalophos by Haemonchus contortus Larvae

2014 ◽  
Vol 58 (12) ◽  
pp. 7475-7483 ◽  
Author(s):  
Andrew C. Kotze ◽  
Angela P. Ruffell ◽  
Aaron B. Ingham
Keyword(s):  
Haemonchus Contortus ◽  
Synergistic Effects ◽  
Cytochromes P450 ◽  
Resistance Mechanism ◽  
Fold Increase ◽  
Protective Role ◽  
Detoxification Enzymes ◽  
Content Type ◽  
Parasitic Worms

ABSTRACTWe used an enzyme induction approach to study the role of detoxification enzymes in the interaction of the anthelmintic compound naphthalophos withHaemonchus contortuslarvae. Larvae were treated with the barbiturate phenobarbital, which is known to induce the activity of a number of detoxification enzymes in mammals and insects, including cytochromes P450 (CYPs), UDP-glucuronosyltransferases (UDPGTs), and glutathione (GSH)S-transferases (GSTs). Cotreatment of larvae with phenobarbital and naphthalophos resulted in a significant increase in the naphthalophos 50% inhibitory concentration (IC50) compared to treatment of larvae with the anthelmintic alone (up to a 28-fold increase). The phenobarbital-induced drug tolerance was reversed by cotreatment with the UDPGT inhibitors 5-nitrouracil, 4,6-dihydroxy-5-nitropyrimidine, probenecid, and sulfinpyrazone. Isobologram analysis of the interaction of 5-nitrouracil with naphthalophos in phenobarbital-treated larvae clearly showed the presence of strong synergism. The UDPGT inhibitors 5-nitrouracil, 4,6-dihydroxy-5-nitropyrimidine, and probenecid also showed synergistic effects with non-phenobarbital-treated worms (synergism ratio up to 3.2-fold). This study indicates thatH. contortuslarvae possess one or more UDPGT enzymes able to detoxify naphthalophos. In highlighting the protective role of this enzyme group, this study reveals the potential for UDPGT enzymes to act as a resistance mechanism that may develop under drug selection pressure in field isolates of this species. In addition, the data indicate the potential for a chemotherapeutic approach utilizing inhibitors of UDPGT enzymes as synergists to increase the activity of naphthalophos against parasitic worms and to combat detoxification-mediated drug resistance if it arises in the field.

scholarly journals Resistance in the Genus Spodoptera: Key Insect Detoxification Genes

Insects ◽  
2021 ◽  
Vol 12 (6) ◽  
pp. 544
Author(s):  
Frédérique Hilliou ◽  
Thomas Chertemps ◽  
Martine Maïbèche ◽  
Gaëlle Le Goff
Keyword(s):  
Abc Transporters ◽  
Molecular Mechanisms ◽  
Spodoptera Exigua ◽  
Cytochromes P450 ◽  
Point Mutations ◽  
Detoxification Enzymes ◽  
Over Expression ◽  
Glutathione S Transferases ◽  
Lepidoptera Noctuidae

The genus Spodoptera (Lepidoptera: Noctuidae) includes species that are among the most important crop pests in the world. These polyphagous species are able to feed on many plants, including corn, rice and cotton. In addition to their ability to adapt to toxic compounds produced by plants, they have developed resistance to the chemical insecticides used for their control. One of the main mechanisms developed by insects to become resistant involves detoxification enzymes. In this review, we illustrate some examples of the role of major families of detoxification enzymes such as cytochromes P450, carboxyl/cholinesterases, glutathione S-transferases (GST) and transporters such as ATP-binding cassette (ABC) transporters in insecticide resistance. We compare available data for four species, Spodoptera exigua, S. frugiperda, S. littoralis and S. litura. Molecular mechanisms underlying the involvement of these genes in resistance will be described, including the duplication of the CYP9A cluster, over-expression of GST epsilon or point mutations in acetylcholinesterase and ABCC2. This review is not intended to be exhaustive but to highlight the key roles of certain genes.

Penicillin-binding proteins of Bacteroides fragilis and their role in the resistance to imipenem of clinical isolates

2005 ◽  
Vol 54 (11) ◽  
pp. 1055-1064 ◽  
Author(s):  
Juan Ayala ◽  
Alberto Quesada ◽  
Santiago Vadillo ◽  
Jerónimo Criado ◽  
Segundo Píriz
Keyword(s):  
Binding Proteins ◽  
Antimicrobial Agents ◽  
Resistance Mechanism ◽  
Bacteroides Fragilis ◽  
Resistance Mechanisms ◽  
Gene Encoding ◽  
Penicillin Binding Proteins ◽  
Mechanism Of Resistance

In this study penicillin-binding proteins (PBPs) of Bacteroides fragilis and the resistance mechanisms of this micro-organism to 11 β-lactam antibiotics were analysed. The study focused on the role of PBP2Bfr and metallo-β-lactamase in the mechanism of resistance to imipenem. The mechanism of β-lactam resistance in B. fragilis was strain dependent. The gene encoding the orthologue of Escherichia coli PBP3 gene (pbpBBfr, which encodes the protein PBP2Bfr) was sequenced in five of the eight strains studied, along with the ccrA (cfiA) gene in strain 119, and their implications for resistance were examined. Differences were found in the amino-acid sequence of PBP2Bfr in strains AK-2 and 119, and the production of β-lactamases indicated that these differences may be involved in the mechanism of resistance to imipenem. In vitro binding competition assays with membrane extracts using imipenem indicated that the PBP that bound imipenem with the highest affinity was PBP2Bfr, and that increased affinity in strain 7160 may be responsible for the moderate susceptibility of this strain to imipenem. In the same way, the importance of the chromosomal class A β-lactamase CepA in the resistance mechanism of the B. fragilis strains NCTC 9344, 7160, 2013E, AK-4, 0423 and R-212 was studied. In these strains this is the principal resistance mechanism to antimicrobial agents studied other than imipenem.

Sign in / Sign up

Export Citation Format

Share Document