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PubMed1986

Liquid-liquid extraction of lactate dehydrogenase from muscle using polymer-bound triazine dyes.

An extract from porcine muscle containing soluble enzymes has been partitioned between the two liquid phases of an aqueous, biphasic system consisting of dextran, polyethylene glycol, and water. The influence of polymer-bound triazine dyes (Cibacron blue F3G-A and Procion yellow HE-3G) on the partition of lactate dehydrogenase and total protein was studied. The effects of pH and concentrations of polymers and buffer on this so-called affinity partitioning were also determined. The two-phase systems were used in extraction procedures for purification of lactate dehydrogenase to a specific activity of 456-494 U (7.6-8.4 mukat) per mg protein. The use of these systems for extraction of enzymes in technical scale is discussed.

Animals↗

PubMed2002

Use of DRYLAB to compare octadecylsilane and carbon supports for reversed-phase chromatography of triazine herbicide test solutes.

One of the most important aspects of method development in reversed-phase high-performance liquid chromatography (RPLC) is the accurate prediction of the resolution as one or more experimental variables (usually the mobile-phase composition) are changed. By use of commercially available computer simulation programs, e.g. Drylab 2000, data from a few initial experimental runs are used to predict how the separation will vary with composition so that a computer program can then rapidly locate the optimum conditions. Assumption of a linear relationship between log k' (retention factor) and phi (volume fraction of organic modifier in the element) minimizes the number of initial runs required for a separation and is usually adequate when the range of phi is not large. In this work the linearity of plots of log k' against phi for octadecylsilane-coated silica (ODS) and carbon-coated zirconia (C-ZrO(2)) columns were compared and the plots were used to determine whether prediction of the separation of triazine herbicides was adequate. Analysis of the slopes and intercepts of such plots are presented for both types of columns.

Chromatography, High Pressure Liquid↗

PubMed2003

Multianalyte determination of different classes of pesticides (acidic, triazines, phenyl ureas, anilines, organophosphates, molinate and propanil) by liquid chromatography-electrospray-tandem mass spectrometry.

This work describes the optimization of a liquid chromatography-electrospray-tandem mass spectrometry (LC-ESI-MS-MS) method for the multianalyte determination of twenty pesticides, selected based on current regulations and extent of use. Chromatographic separation was carried out on a Purospher STAR RP-18e column using gradient acetonitrile-water as mobile phase. Triazines, phenylureas, organophosphates, anilines, and molinate were determined in the positive ionization mode, and acidic pesticides and propanil in the negative ion mode. Two different precursor ion-product ion transitions were selected for each analyte and monitored under time scheduled multiple reaction monitoring (MRM) conditions. The optimized method was shown to be linear in the range 1 to 1000 ng/mL with correlation coefficients higher than 0.99 for all but one (diazinon) of the analytes, very sensitive (with limits of detection between 0.010 and 4.528 ng/mL), and repeatable (with relative standard deviations, calculated from the replicate analysis of standard mixtures, lower than 14%). The present work was also devoted to the elucidation of the structures of the principal fragment ions obtained after collision-induced dissociation of the pesticides investigated, an aspect often overlooked in the literature.

Aniline Compounds↗

PubMed2003

Assessing the impact of triazine herbicides on organophosphate insecticide toxicity to the earthworm Eisenia fetida.

A standard Organization for Economic Cooperation and Development (OECD) filter paper test was used to assess the acute toxicity of chlorpyrifos, atrazine, cyanazine, and simazine to the earthworm Eisenia fetida. Acute toxicity of chlorpyrifos was also determined in combination with the three-triazine herbicides. Surprisingly, atrazine and cyanazine caused mortality at concentrations lower than chlorpyrifos. Atrazine and cyanazine also increased the toxicity of chlorpyrifos 7.9- and 2.2-fold, respectively. However, simazine caused no toxicity to the worms and did not affect chlorpyrifos toxicity in binary mixture experiments. Possible mechanisms for the greater-than-additive toxicity for the binary combinations of atrazine and cyanazine with chlorpyrifos were investigated, including changes in uptake and biotransformation rates of chlorpyrifos in the presence of atrazine. Uptake of chlorpyrifos into the worms decreased slightly when atrazine was present in the system, therefore eliminating increased uptake as a possible explanation for the increased toxicity. Body residue analysis of worms indicated increased metabolite formation, suggesting the greater-than-additive response may be due to increased biotransformation to more toxic oxon metabolites.

Animals↗

PubMed2004

Toxicologic and histopathologic response of the terrestrial salamander Plethodon cinereus to soil exposures of 1,3,5-trinitrohexahydro-1,3,5-triazine.

Red-backed salamanders (Plethodon cinereus) were exposed to four different concentrations of 1,3,5-trinitrohexahydro-1,3,5-triazine (RDX) in soil under controlled laboratory conditions for 28 days. Wild-caught P. cinereus (N = 20/treatment) were exposed to target concentrations of 5,000, 1000, 100, 10, and 0 mg RDX/kg soil (dry wt) using a microcosm design. Animals were fed 5 to 10 uncontaminated mutant Drosophila flies every 3 days and monitored daily. Animals were weighed 1 day before being placed in treatment and weekly thereafter. RDX concentrations in soil were analytically determined after the compound was added and mixed at the beginning, the midpoint, and the end of exposure. RDX soil concentrations were relatively stable throughout the exposure period. Signs of overt toxicity were observed primarily in the highest exposure group. Salamanders exposed to 5,000 mg RDX/kg soil exhibited signs of neuromuscular effects (lethargy, gaping, hypersensitivity, tremors) and exhibited significant weight loss. A single moribund animal from this group lost >20% of its original body weight and was killed. Animals in this exposure group also lost weight relative to animals in other treatments. Histopathologic evaluations, including an evaluation of melanomacrophage parameters, indicated no strong treatment-related findings. This study provided information regarding the effects from subchronic dermal exposure of a terrestrial amphibian species to RDX in soil and provides a microcosm approach to the evaluation of toxicity of contaminants in soil to a terrestrial vertebrate.

Administration, Cutaneous↗

PubMed2004

Characterization of Pseudomonas sp. HK-6 cells responding to explosive RDX (hexahydro-1,3,5-trinitro-1,3,5-triazine).

The cellular responses of Pseudomonas sp. HK-6 to explosive hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX) have been extensively analyzed in this study. The stress shock proteins, which might contribute to enhancing the cellular resistance to the cytotoxic effect of RDX, were induced at different concentrations of RDX used as a substrate for cell culture of Pseudomonas sp. HK-6. The proteins were identified as 70-kDa DnaK and 60-kDa GroEL by SDS-PAGE and Western blot using the anti-DnaK and anti-GroEL monoclonal antibodies. The stress shock proteins induced by RDX were found to increase in proportion to the RDX concentration used for this work. Analysis of membrane fatty acids of strain HK-6 following exposure to RDX showed that the amounts of dominant lipids 16:1 omega7c/15:0 iso 2OH, 16:0 and 18:1 omega7c/omega9t/omega12t decreased substantially or were not detected in the cells exposed to RDX, while amounts of lipids 10:0 iso, 14:1 omega5c/omega5t and 16:10 methyl increased dramatically. Scanning electron microcopy analyses revealed the presence of perforations and irregular rod shapes with wrinkled surfaces for cells treated with 0.135 mM RDX for 12 h, suggesting that RDX has a substantial cytotoxic impact on cells of strain HK-6.

Chaperonin 60↗

PubMed2005

Prediction of growth and biotransformation rates of hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX) in the presence of barium.

The biotransformation of explosives has been investigated by many researchers. Bioremediation of soil and water contaminated with hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX) is becoming the method of choice for clean-up of a variety of sites. In this study, we investigated biotransformation of RDX in the presence of barium. Ba is a metal commonly found in combination with RDX at sites requiring remediation. RDX was biotransformed by both a consortium of bacteria and an isolate from the consortium under anoxic conditions using a rich medium. However, Ba inhibited cell growth under both aerobic and anoxic conditions and slowed biotransformation rates by 40%. RDX and Ba inhibited growth of the isolate more than growth of the consortium. An additive inhibition model is proposed that accurately predicts the reduced growth rates observed.

Barium↗

PubMed2004

Anaerobic biodegradation of hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX) by Acetobacterium malicum strain HAAP-1 isolated from a methanogenic mixed culture.

In previous work, we studied the anaerobic biodegradation of hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX) by a methanogenic mixed culture that biodegrades RDX by using H2 as the sole electron donor. Strain HAAP-1 was isolated after enriching for the homoacetogens in a mineral medium containing RDX and an H2-CO2 (80:20) headspace. Strain HAAP-1 degraded 29.0 microM RDX in <14 days and formed 13.0 mM acetate when grown in a mineral medium with an H2-CO2 headspace. Methylenedinitramine was observed as a transient intermediate, indicating ring cleavage had occurred. In live cultures containing an N2-CO2 headspace, RDX was not degraded, and no acetate was formed. The 16S rRNA gene sequence for strain HAAP-1, consisting of 1485 base pairs, had a 99.2% and 99.1% sequence similarity to Acetobacterium malicum and A. wieringae, respectively. This is the first report of RDX degradation by a homoacetogen growing autotrophically and extends the number of genera known to carry out this transformation.

Acetic Acid↗

PubMed2006

Hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX) serves as a carbon and energy source for a mixed culture under anaerobic conditions.

We studied the anaerobic biodegradation of hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX) in a mineral medium by a mixed culture. RDX degradation activity was maintained for more than a year with only the addition of RDX. We observed a steady increase in the protein concentration of the culture from 4.8 microg mL(-1) to more than 24.4 microg mL(-1), a >400% increase. There was only a slight increase in protein in the RDX unamended control bottles containing live culture, increasing from 4.8 microg mL(-1) to 7.8 microg mL(-1). Radiolabeled (14)C-RDX confirmed mineralization of the cyclic nitramine to (14)CO(2). After 164 days, 35% of the radiolabel was recovered as 14CO2. This is the first report demonstrating the mineralization of RDX when it serves as a growth substrate for a mixed culture.

Anaerobiosis↗

PubMed2005

Hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX) degradation by Acetobacterium paludosum.

Substrates and nutrients are often added to contaminated soil or groundwater to enhance bioremediation. Nevertheless, this practice may be counterproductive in some cases where nutrient addition might relieve selective pressure for pollutant biodegradation. Batch experiments with a homoacetogenic pure culture of Acetobacterium paludosum showed that anaerobic RDX degradation is the fastest when auxiliary growth substrates (yeast extract plus fructose) and nitrogen sources (ammonium) are not added. This bacterium degraded RDX faster under autotrophic (H2-fed) than under heterotrophic conditions, even though heterotrophic growth was faster. The inhibitory effect of ammonium is postulated to be due to the repression of enzymes that initiate RDX degradation by reducing its nitro groups, based on the known fact that ammonia represses nitrate and nitrite reductases. This observation suggests that the absence of easily assimilated nitrogen sources, such as ammonium, enhances RDX degradation. Although specific end products of RDX degradation were not determined, the production of nitrous oxide (N2O) suggests that A. paludosum cleaved the triazine ring.

Acetobacterium↗

PubMed1984

Affinity partitioning of albumin and alpha-fetoprotein in an aqueous two-phase system using poly(ethylene glycol)-bound triazine dyes.

Human albumin and alpha-fetoprotein are partitioned in an aqueous two-phase system composed of 10% (w/w) Dextran and 7.5% (w/w) poly(ethylene glycol). When a small amount of poly(ethylene glycol) is replaced by Cibacron Blue F3G-A-liganded poly(ethylene glycol) the partition coefficient, K, of albumin increases by the factor of about 4000 whereas the K value of alpha-fetoprotein undergoes only a small change. The change of the partition coefficient in a logarithmic scale induced by increasing dye-polymer concentrations turned out as a useful measure for the affinity of albumin and alpha-fetoprotein to the dyes. The effect of pH and salt concentration on the affinity partition of albumin and alpha-fetoprotein is demonstrated. The partition of the two proteins in presence of Cibacron Blue F3G-A-liganded poly(ethylene glycol) is compared with seven other triazine dye-poly(ethylene glycol) derivatives.

Charcoal↗

PubMed1986

Affinity precipitation of lactate dehydrogenase with a triazine dye derivative: selective precipitation of rabbit muscle lactate dehydrogenase with a procion blue H-B analog.

A simple methoxylated derivative of the triazine dye, Procion blue H-B, selectively precipitates rabbit muscle lactate dehydrogenase from solution. Optimum protein precipitation occurred at an enzyme subunit:dye ratio of approximately 2:1 and was fully reversible upon addition of competitive ligands such as NADH. With a crude extract of rabbit muscle, affinity precipitation with the dye followed by dissolution with NADH yielded homogeneous lactate dehydrogenase in 97% overall yield.

Animals↗

PubMed1986

Specifically increased solubility of enzymes in polyethyleneglycol solutions using polymer-bound triazine dyes.

The enzymes glucose-6-phosphate dehydrogenase (EC 1.1.1.49) and 3-phosphoglycerate kinase (EC 2.7.2.3), present in an extract of Bakers' yeast, are largely kept in solution by minor amounts of polyethylene glycol-bound triazine dyes (Procion yellow HE-3G and Procion olive MX-3G) even when the solution contains such concentrations of polyethylene glycol (12.5% w/w) which normally precipitate the enzymes. The specific prevention from precipitation can be used for purification of enzyme, preferentially in dealing with crude extracts, which has been demonstrated in this work. A 3.4-fold purification of glucose-6-phosphate dehydrogenase has been achieved with good recovery (93%). Further purification has been possible by combining the recovered (enzyme-containing) supernatant liquid with a solution of dextran which generates an aqueous two-phase system. The lower, dextran-containing phase extracts part of the remaining bulk proteins leaving the target enzyme in the upper phase. The advantages of this method for enzyme purification in large scale are discussed.

Coloring Agents↗

PubMed1986

Mapping of the triazine binding site to a highly conserved region of the QB-protein.

A number of herbicide classes, including the s-triazines and ureas (atrazine, diuron) inhibit photosynthetic electron transport via a direct interaction with the QB-protein. This protein, also known as the 32-kDa protein or herbicide binding protein, is believed to bind the plastoquinone QB, which functions as the second stable electron acceptor at the reducing side of Photosystem II. The site of covalent attachment of the photoaffinity herbicide analog azido-[14C]atrazine to the QB-protein of spinach chloroplast thylakoid membranes has been determined. Two amino acid residues are labeled; one residue is methionine-214, the other lies between histidine-215 and arginine-225. Both residues are within a region of the amino acid sequence which is highly conserved between the QB-protein and the L and M reaction center proteins of Rhodopseudomonas capsulata and R. sphaeroides. This region includes the site of a mutation which results in diuron resistance in Chlamydomonas reinhardi (valine-219). However, this region is well removed from point mutations at phenylalanine-255 (which gives rise to atrazine resistance in C. reinhardi) and at serine-264, (which results in extreme atrazine resistance in C. reinhardi and naturally occurring weed biotypes). The patterns of labeling and mutation imply that the quinone and herbicide binding site is formed by at least two protein domains.

Affinity Labels↗

PubMed1981

Affinity chromatography on immobilised triazine dyes. Studies on the interaction with multinucleotide-dependent enzymes.

A systematic investigation into the interaction of several triazinyl dyes with two enzymes from purine metabolism, IMP dehydrogenase (IMP: NAD+ oxidoreductase, EC 1.2.1.14( and adenylosuccinate synthetase (IMP: L-aspartate ligase (GDP-forming), EC 6.3.4.4) has been conducted. Evidence from kinetic inhibition studies, enzyme inactivation with specific affinity labels and specific elution techniques from agarose-immobilised dyes indicate that triazine dyes such as Procion Blue H-B (Cibacron Blue F3G-A), Red HE-3B and Red H-3B are able to differentiate between the nucleotide-binding sites of these enzymes. This information has been exploited to design specific elution techniques for the purification of these enzymes by affinity chromatography.

Adenylosuccinate Synthase↗

PubMed1985

Inhibition of rat brain galactocerebroside sulfotransferase by triazine aromatic dyes: interaction with the 3'-phosphoadenosine 5'-phosphosulfate binding site.

The mechanism of inhibition of rat brain cerebroside sulfotransferase (EC 2.8.2.11) by a series of triazine aromatic dyes was examined. These dyes are putative site-specific probes of the "dinucleotide fold". All of the dyes examined were competitive inhibitors of cerebroside sulfotransferase with respect to 3'-phosphoadenosine 5'-phosphosulfate (PAPS) binding. In addition, the binding of the dye, Congo Red, to the sulfotransferase was associated with a red shift in its absorption spectrum. Based on these results, it is suggested that rat brain cerebroside sulfotransferase contains a "dinucleotide fold" as a structural feature of the protein.

Adenine Nucleotides↗

PubMed1983

Inhibition of a methotrexate-insensitive dihydrofolate reductase from L5178Y cells by substituted triazines and quinazolines.

Inhibition by a variety of substituted triazines and quinazolines of a methotrexate-insensitive form of dihydrofolate reductase from highly MTX-resistant L5178Y mouse leukemia cells was examined. Some of these compounds were significantly more potent than MTX (up to 100-fold). Two triazenes, terminally substituted with benzenesulfonylfluoride residues, were approximately 30-fold more potent than MTX. Quinazoline analogs of folic acid with alterations in different parts of the molecule varied in their potencies as inhibitors. Although none of the compounds tested was as potent as MTX against MTX-sensitive dihydrofolate reductases, these studies show that some types of folate antagonists have increased specificity against this MTX-insensitive dihydrofolate reductase. This finding increases the likelihood that it may be possible to produce compounds with marked specificity for the insensitive reductase. Such compounds might have utility in antifolate combinations designed to overcome methotrexate resistance.

Animals↗

PubMed1985

The effect of s-triazine-type pesticides and chlorinated hydrocarbons on lactate dehydrogenase.

The effect of pesticides on nontarget organisms was studied by following their effect on enzymes from these organisms in vitro. s-Triazines substituted in positions 2, 4, and 6 behaved as inhibitors of plant and animal lactate dehydrogenase, acting competitively with respect to the coenzyme. The inhibition constants were of the order of 10(-3) M and the structure of the substituents exerted no pronounced effect on the inhibition type and the value of the inhibition constant. Polycyclic chlorinated hydrocarbons were found to be much stronger inhibitors, with inhibition constants of the order of 10(-5) M. These substances inhibit the reaction catalyzed by lactate dehydrogenase not only by reaction with the enzyme, but also by a probable direct reaction with the coenzyme.

Animals↗