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PubMed2001

Contamination of the coastal waters of Bermuda by organotins and the triazine herbicide Irgarol 1051.

A study of the distribution of the 'booster' biocide 2-methylthio-4-tert-butylamino-6-cyclopropyl amino-s-triazine (Irgarol 1051) was carried out in the coastal waters of Bermuda. Irgarol 1051 concentrations (as determined by GC/MS) up to 590 ng l-1 have been measured within Hamilton Harbour. The data presented herein unequivocally demonstrate contamination of the coastal system of Bermuda by Irgarol 1051. Concurrently, TBT concentrations were measured and results indicate that levels are falling through legislated changes in antifouling treatments, from 220 ng l-1 in 1990 to < 20 ng l-1 (as Sn) by 1995, in the open water area of Hamilton Harbour. Concentrations of TBT immediately offshore from a boatyard were found to be > 600 ng l-1 (Sn), indicating continuing release due to painting operations and sediments in the area.

Bermuda↗
PubMed2002

Fenton oxidation of hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX) and octahydro-1,3,5,7-tetranitro-1,3,5,7-tetrazocine (HMX).

Oxidation of the high explosives hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX) and octahydro-1,3,5,7-tetranitro-1.3,5,7-tetrazocine (HMX) using Fenton's reagent proceeds rapidly between 20 degrees C and 50 degrees C at pH 3. At an H2O2: Fe2+: RDX molar ratio of 5,178: 48: 1, RDX and HMX were completely removed in 1 to 2 h. All the experimental data could be fit to a pseudo first-order rate equation. The reaction rate was also strongly dependent on Fenton's reagent concentrations. NO3- and N2 were identified as nitrogen byproducts from RDX and HMX oxidation. The experiment with radiolabeled RDX showed that approximately 37% of organic carbon in RDX was mineralized to CO2. We observed formaldehyde and formic acid as a short-lived intermediate. No other volatile or nonvolatile byproducts were found from GC/MS analysis. The results show that RDX and HMX can be effectively mineralized with Fenton's reagents.

Azocines↗
PubMed2003

Biodegradation pathways of hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX) by Clostridium acetobutylicum cell-free extract.

Hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX), a military high explosive, is becoming an increasingly important pollutant in the US. The cleanup of RDX-contaminated soil and groundwater has been a serious challenge due to its recalcitrance in the environment. This study was conducted to determine the biodegradation kinetics of RDX by crude cell extract of Clostridium acetobutylicum (ATCC 824), and to examine whether this bacterium will carry out reductive transformation pathways similar to the transformation of 2,4,6-trinitrotoluene (TNT), 2,4- and 2,6-dinitrotoluenes (DNTs) we have reported previously. Batch studies on the anaerobic transformation of RDX were conducted in serum bottles with U-ring-14C-RDX. RDX and its transformation products were quantified by HPLC and qualified by LC/ MS interfaced to two soft ionization techniques--an atmospheric pressure ionization and an electron spray ionization (API-ES). Results demonstrated that C. acetobutylicum is capable of transforming RDX with H2 as the electron donor. The transformation followed a zero-order kinetics and the rates increased with increasing H2. RDX was transformed into several polar intermediates that could not be separated by reverse-phase HPLC and its molecular ions were unstable under the condition of commonly used electron impact detector. Using a polar and water immiscible solvent (ethyl acetate) and the softer MS ionization techniques, mass spectroscopy detected the presence of several RDX derivatives including mononitroso-, monohydroxylamino-, mononitrosomonohydroxylamino-, monoamino-, diamino-, and triamino-compounds. The presence of hydroxylamino compounds is analogous to the transformation of TNT and DNTs we elucidated previously.

Anaerobiosis↗
PubMed2003

Non-degradable triazine substrates of atrazine and cyanuric acid hydrothermally and in supercritical water under the UV-illuminated photocatalytic cooperation.

Strong oxidation by titanium dioxide photocatalysis can occur by photodegradation of organic contaminants in air and water. Some endocrine disruptors such as 2,4-dichlorophenoxy acetic acid (;;; ), 2,4-dichlorophenol (;;; ), nonylphenol (; ), bisphenol A (), diethyl phthalate (; ), etc. which can be neither biodegraded by bacteria nor degraded thermally can be degraded by TiO(2) photocatalytic treatment. However, incomplete photomineralization partly occurred, when TiO(2) photocatalytic degradation is employed for the treatment of certain endocrine disruptors. For example, no atrazine pesticide having triazine skeleton can be completely mineralized even by a photocatalytic procedure; the photodegradation of atrazine ultimately stops at the intermediate step of cyanuric acid, which cannot be photodegraded even after long illumination times (). In this study, the decomposition of atrazine and cyanuric acid was carried out with a device combining photocatalytic degradation in supercritical water (scH(2)O) or hydrothermal water (hyH(2)O). Atrazine and cyanuric acid can be degraded by the cooperation of either scH(2)O or hyH(2)O and UV illuminated TiO(2)-photocatalytic dispersed system under the fixed pressure of 23 MPa at 623 K or 683 K in a 120-ml Hastelloy batch reactor. The photocatalytic degradation method under high temperature and pressure has found appropriate for the photocatalytic oxidation of acetic acid and 2-chlorobiphenyl under continuous flow conditions at 160 degrees C and 20 atm (). In addition, the wet peroxide oxidation of PCBs by high temperature and pressure has been reported (). The main aims of this research are following. (i): the degradation of atrazine and cyanuric acid within the scH(2)O or hyH(2)O, (ii) the decomposition of atrazine and cyanuric acid catalyzed by TiO(2) particles under scH(2)O or hyH(2)O, and the synergistic effect for several reactions with TiO(2) and scH(2)O or hyH(2)O, and (iii) the mineralization yield of nitrogen and chlorine atoms concerning the chemical structures of atrazine or cyanuric acid (only nitrogen).

Atrazine↗
PubMed2003

The use of Enterobacter cloacae ATCC 43560 in the development of a two-phase partitioning bioreactor for the destruction of hexahydro-1,3,5-trinitro-1,3,5-s-triazine (RDX).

Research on the biodegradation of explosives has focussed exclusively on the treatment of contaminated soil and water. In the present work the anaerobic degradation of hexahydro-1,3,5-trinitro-1,3,5-s-triazine (RDX) by Enterobacter cloacae ATCC 43560 was investigated, and a two-phase partitioning bioreactor (TPPB) was developed for the destruction of pure, past-date munitions. TPPBs are characterized by a cell-containing aqueous phase, and an immiscible and biocompatible organic phase into which very large amounts of toxic and/or insoluble substrates can be dissolved. Based on equilibrium partitioning, the substrate is then transported to the cells, in response to their metabolic requirements, providing a means of demand-based substrate delivery, and high bioreactor productivity. Through consideration of the critical logP of E. cloacae, whether various classes of solvents could be used as sole carbon and energy sources, the capacity of various organics to dissolve RDX, and solvent cost, 2-undecanone was ultimately selected as the delivery solvent for the TPPB. Using this solvent, both batch and fed-batch operation of the TPPB were undertaken, and the volumetric degradation rate of RDX was found to be higher in this arrangement than any previous values reported in the literature. This work has demonstrated the potential of a method for the destruction of decommissioned munitions involving the dissolution of RDX in 2-undecanone, the use of the RDX-rich solvent as the second phase in a TPPB to degrade this explosive, and the subsequent recycling and re-use of the solvent.

Anaerobiosis↗
PubMed1984

Carcinogenic effects of 3-di(hydroxymethyl)-amino-6-(5-nitro-2-furylethenyl)-1,2,4-triazine in the small intestine of Ishibashi and Wistar rats.

The carcinogenic effect of an oral administration of 3-di(hydroxymethyl)-amino-6-(5-nitro-2-furylethenyl)-1,2,4-triazin e (DHNT) was studied in two strains of rats. Ishibashi (IS) rats have a perpetual absorption disturbance while Wistar Imamichi (WI) rats have no such disturbance. Small intestinal carcinomas developed in 10 out of 15 (66.7%) IS rats and in all 8 (100%) Wistar rats given 3,500 ppm DHNT for 43 weeks. The total number of lesions in the small intestine was 24 in IS rats and 21 in WI rats. Histologically, the lesions consisted of 7 mucosal dysplasias, 4 adenomas and 12 tubular and 1 papillary adenocarcinoma in IS rats, and 3 mucosal dysplasias, 1 adenomas, and 15 tubular and 2 papillary adenocarcinomas in WI rats. The levels of plasma leucine aminopeptidase, copper and total protein were lower, while blood urea nitrogen was higher in both strains of rats given DHNT than in control rats.

Adenocarcinoma↗
PubMed1998

Affinity chromatography of serine proteases on the triazine dye ligand Cibacron Blue F3G-A.

The interaction between complement component factor B and the triazine dye ligand Cibacron Blue F3G-A coupled to a cross-linked agarose matrix (Blue Sepharose) was found to involve the Bb part of the molecule, and to be inhibited by benzamidine. Human, chicken and rainbow trout factor B which had bound to Blue Sepharose could, subsequently be eluted with benzamidine. Other serine proteases (C2, factor II, factor IX, trypsin, chymotrypsin, proteinase 3) also bound to Blue Sepharose but only those belonging to the trypsin family could be eluted with benzamidine. Trypsin treated with the active-site inhibitor phenylmethylsulfonyl fluoride did not bind to Blue Sepharose and pretreatment of Blue Sepharose with benzamidine did not influence binding of proteases. We conclude that trypsin-like serine proteases can be purified on Blue Sepharose and that the interaction of these serine proteases with Blue Sepharose involves the active site of the enzyme.

Animals↗
PubMed2003

Multi-analyte assay for triazines using cross-reactive antibodies and neural networks.

A biosensor system based on total internal reflectance fluorescence (TIRF) was used to discriminate a mixture of the triazines atrazine and simazine. Only cross-reactive antibodies were available for these two analytes. The biosensor is fully automated and can be regenerated allowing several hundreds of measurements without any user input. Even a remote control for online monitoring in the field is possible. The multivariate calibration of the sensor signal was performed using artificial neural networks, as the relationship between the sensor signals and the concentration of the analytes is highly non-linear. For the development of a multi-analyte immunoassay consisting of two polyclonal antibodies with cross-reactivity to atrazine and simazine and different derivatives immobilised on the transducer surface, the binding characteristics between these substances like binding capacity and cross-reactivity were characterised. The examination of three different measurement procedures showed that a two-step measurement using only one antibody per step allows a quantification of both analytes in a mixture with limits of detection of 0.2 microg/l for atrazine and 0.3 microg/l for simazine. The biosensor is suitable for online monitoring in the field and remote control is possible.

Algorithms↗
PubMed1999

Trace level detection of hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX) by microimmunosensor.

Reported in this paper is the development and characterization of a highly sensitive microcapillary immunosensor for the detection of the explosive, hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX). The immunosensor exploits antibodies as recognition elements for target antigens, fluorescence dye conjugates for reporter molecules and fused silica microcapillaries for its high surface-to-volume ratio. Detection of RDX with the microcapillary immunosensor requires covalent immobilization of anti-RDX antibodies on the inner core of the microcapillaries via heterobifunctional cross-linker chemistry. Subsequent saturation of all antibody binding domains follows with a synthetically prepared fluorescent analog of RDX. Displacement immunoassays were performed with the microcapillary immunosensor with the injection of unlabeled RDX at concentration levels from 1 part-per-trillion (pptr) to 1000 part-per-billion (ppb). As unlabeled RDX reaches the binding domain of the antibody, fluorescent RDX analog is displaced from the antibody, flows downstream and is measured by a spectrofluorometer. Fluorescence measurements of the displaced fluorescent RDX analog were equated to a standard calibration curve to quantify sample concentration. Complete evaluation of the RDX microcapillary immunosensor for selectivity and sensitivity was performed based on the following criteria: variable flow rates, antibody cross-reactivity, reproducibility and cross-linker (carbon spacer) comparison. Results indicate the lowest detectable limit (LDL) for RDX is 10 pptr (ng/l) with a linear dynamic range from 0.1 to 1000 ppb (ug/l).

Biosensing Techniques↗
PubMed2002

Imidazo[5,1-f]triazin-4(3H)-ones, a new class of potent PDE 5 inhibitors.

2-aryl-substituted imidazo[5,1-f][1,2,4]triazin-4(3H)-ones represent a new class of potent cGMP-PDE 5 inhibitors that prove to be superior to other purine-isosteric inhibitors. Subnanomolar inhibitors of PDE 5 with activity in in vivo models for erectile dysfunction have been identified. BAY 38-9456 (Vardenafil-hydrochloride) has been selected for clinical studies in the indication of erectile dysfunction.

3',5'-Cyclic-GMP Phosphodiesterases↗
PubMed2003

Identification of a novel class of orally active pyrimido[5,4-3][1,2,4]triazine-5,7-diamine-based hypoglycemic agents with protein tyrosine phosphatase inhibitory activity.

A novel series of orally active pyrimido[5,4-3][1,2,4]triazine-5,7-diamine-based hypoglycemic agents have been identified. These compounds show non-selective inhibitory properties against a panel of protein tyrosine phosphatases including PTP1B. Compounds 12 and 13 display oral glucose lowering effects in ob/ob mice.

Administration, Oral↗
PubMed2003

Synthesis of solution-phase combinatorial library of 4,6-diamino-1,2-dihydro-1,3,5-triazine and identification of new leads against A16V+S108T mutant dihydrofolate reductase of Plasmodium falciparum.

An efficient method to synthesize solution-phase combinatorial library of 1-aryl-4,6-diamino-1,2-dihydro-1,3,5-triazine was developed. The strategy involved an acid-catalyzed cyclocondensation between arylbiguanide hydrochlorides and carbonyl compounds in the presence of triethyl orthoacetate as water scavenger. A 96-membered combinatorial library was constructed from 6 aryl biguanides and 16 carbonyl compounds. Screening of the library by iterative deconvolution method revealed two candidate leads which are equally active against wild-type Plasmodium falciparum dihydrofolate reductase, but are about 100-fold more effective against the A16V+S108T mutant enzyme as compared to cycloguanil.

Amino Acid Substitution↗
PubMed1999

Phosphodiesterase 4 inhibitors as airways smooth muscle relaxant agents: synthesis and biological activities of triazine derivatives.

A series of triazine derivatives was synthesized. The compounds were evaluated for tracheal smooth muscle relaxant and type 4 phosphodiesterase inhibitory activities. A highly significant correlation was observed between the two effects. Two compounds exhibited potent relaxant activity (EC50: 17 and 24 nM) and might be useful for the treatment of asthma.

3',5'-Cyclic-AMP Phosphodiesterases↗
PubMedDate not supplied

Cross-linking of protein subunits by 1,3, 5-triacryloyl-hexahydro-s-triazine.

Six difunctional and trifunctional derivatives of acrylamide were synthesized and investigated as potential protein lysine residue cross-linking agents. 1,3,5-Triacryloyl-hexahydro-s-triazine (TAT) was considered the best. The rate constants for the reactions of TAT with model nucleophiles in water solution at 25 degreesC were with the glycine anion amino group, 7.69 x 10(-3) M-1 s-1; with the anionic form of the N-acetyl-L-cysteine thiol group, 5.54 M-1 s-1; and with the Nalpha-acetyl-L-histidine imidazole ring, 1.19 x 10(-5) M-1 s-1 (at pH 9.0). The kinetics of modification of amino groups by TAT were studied for several proteins: alpha1-casein, bovine serum albumin, recombinant human growth hormone, recombinant human interferons-alpha2b, and -gamma. The results indicate that if proteins are associated into oligomeric structures in water, their subunits are effectively cross-linked by TAT.

Cross-Linking Reagents↗
PubMed2001

Absorption changes induced by the binding of triazines to the QB pocket in reaction centers of Rhodobacter capsulatus.

Inhibitors which block electron transfer from the primary (Q(A)) to the secondary (Q(B)) quinone of the bacterial reaction center are competing with the pool ubiquinones for binding at the Q(B) pocket. Due to the much greater stability of the semiquinone state Q(B)(-) compared with fully oxidized or reduced quinone, a displacement of the inhibitors takes place after one flash from state Q(A)(-)I to state Q(A)Q(B)(-). This process can be monitored from near-IR absorption changes which reflect local absorption shifts specific to Q(A)(-) and Q(B)(-). An anomalous behavior was observed when using triazines in chromatophores of R. capsulatus: the IR absorption change reflecting the formation of Q(B)(-) after one flash was absent. A normal transient decay of this signal was, however, triggered by a second flash, followed by a rapid return to the baseline. We show that this phenomenon is due to an absorption change induced by inhibitor binding (thus present in the dark baseline), with a spectrum close to that of Q(B)(-), so that the Q(B)(-) changes are canceled out during the inhibitor displacement process. On the second flash, one monitors the destruction of the semiquinone, leading transiently to the Q(A)Q(B) state, followed by inhibitor rebinding. This allows a direct measurement of the binding kinetics. This behavior was observed both in chromatophores and in isolated reaction centers from R. capsulatus, but not in R. sphaeroides.

Atrazine↗
PubMedDate not supplied

Combinatorial synthesis of heterocycles: solid-phase synthesis of 6-amino-2,4-dioxo-3,4-dihydro-1,3,5-triazine derivatives.

A new solid-phase synthesis of trisubstituted 6-amino-2,4-dioxo-3,4-dihydro-1,3,5-triazines from a resin-bound amine component is described. The amine was readily converted to the corresponding polymer-bound S-methylthiopseudourea, which upon reaction with secondary amines gave the disubstituted guanidines. Cyclization of the polymer-bound guanidines with chlorocarbonylisocyanate afforded the triazinediones. The third point of diversity was introduced by the Mitsunobu reaction. The method is amenable for iterative combinatorial library generation.

Amines↗