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PubMed2005

Determination of TNT and its metabolites in water samples by voltammetric techniques.

Square-wave voltammetry with the hanging drop mercury electrode as the working electrode was used for the determination of ultratraces of explosives in aqueous solution. It was shown that the strong pressure dependence of the pneumatically controlled multimode electrode system of a conventional Metrohm apparatus could be compensated by an additional pressure regulation, through which the pressure variations could be decreased when switching from deaeration to the static measurements. By using square-wave voltammetry with this electrode system after this modification the limits of detection for 2,4,6-trinitrotoluene (TNT) and other TNT-metabolites could be decreased down to 0.2 microg L(-1) when using a measurement time of 6 min. Also a simultaneous determination of TNT and hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX) was shown to be possible over a wide linear range and the detection limits then were 2.2 microg L(-1) for TNT and 25 microg L(-1) for RDX. By applying the highly stable and adjustable pressure as mentioned before, the calibrations could be kept stable over a period of up to 1 week.

Calibration↗
PubMed2006

A thermodynamic study on the complexation between riboflavin and a diaminotriazine derivative mediated by triple hydrogen bonds at water/oil interfaces.

The changes in Gibbs free energy (DeltaG (int)), enthalpy (DeltaH (int)) and entropy (TDeltaS (int)) upon complexation between riboflavin (RF) and N,N-dioctadecyl-[1,3,5]triazine-2,4,6-triamine (DTT), mediated by triple hydrogen bonds at water/carbon tetrachloride, trichloroethylene and chloroform interfaces, were determined via temperature-controlled interfacial tension measurements. It was shown that hydrogen bonding interactions between RF and DTT were best characterized by large and negative DeltaH (int) values, unlike those predicted from either the polarity in each phase or the arithmetic average of the polarities in the two phases. Furthermore, the DeltaH (int) values became more positive as the dielectric constant of the oil phase was increased. These results strongly indicate that DeltaH (int) is governed by the dielectric properties of the oil phase. Adsorption of RF, DTT and the RF-DTT complex at the water/oil interface gave rise to restrictions on the translational and rotational motions of these species, as demonstrated by the DeltaS (int) values observed, which is another characteristic of interfacial complexation. The thermodynamic parameters evaluated in the present study revealed the characteristic complexation behavior that occurs at a water/oil interface, as mediated by hydrogen bonding.

Hydrogen Bonding↗
PubMed2001

Electrospray ionization gas-phase electrophoresis under ambient conditions and it's potential or high-speed separations.

A moderately high resolution nanoelectrospray ionization gas-phase electrophoresis instrument was constructed and evaluated for simple high-speed separations of several groups of compounds. The insertion of a plate containing a 1.6 cm diameter exit orifice, 2.5 cm from the location of electrospray, allowed ions to be created and desolvated under ambient conditions with minimal solvent contamination to the drift tube. Ion separation selectivity is discussed and shown to be slightly altered by changing the drift gas flow rate. Issues of using gas-phase electrophoresis as a high-speed separation technique are discussed. Gas-phase electrophoresis-spectra of selected benzodiazepines, triazine herbicides, and simple combinatorial chemistry libraries are demonstrated.

Alprazolam↗
PubMed2001

Electrochemical behavior and voltammetric determination of the herbicide metribuzin at mercury electrodes.

The electrochemical behavior of the herbicide metribuzin (4-amino-6-tert-butyl-4,5-dihydro-3-methylthio-1,2,4-triazin-5-one) at mercury electrodes was studied in aqueous solutions by direct current (DC) and tast polarography, differential pulse (DPV) and cyclic voltammetry (CV), and controlled-potential coulometry. The electrolysis products were separated and identified by chromatographic techniques combined with mass spectrometric detection. The reduction process in acid media includes two irreversible steps. In the first four-electron step the N-NH2 and the 1,6-azomethine bonds are reduced. The second step leads to the formation of 5-tert-butyl-2,3,4,5-tetrahydroimidazol-4-one at the mercury-pool electrode. The first reduction step combined with adsorptive accumulation of the herbicide molecule at the mercury electrode surface was used for its determination by differential pulse adsorptive stripping voltammetry (DPAdSV). Calibration curves were linear in the range 1-30 microg L(-1) with a detection limit of 0.27 microg L(-1) (1 nmol L(-1)) under the conditions used (buffer pH 4.5, Eacc = -0.45 V relative to Ag/AgCl and tacc = 10 s). Preconcentration on solid-phase extraction columns (SPE-phenyl) was used for the determination of very small amounts of metribuzin in river water samples. Recovery was approximately 97%. The reproducibility of the analytical procedure including SPE treatment and DPV determination was expressed as relative standard deviations of 2.53 and 3.66% for 2 and 6 microg L(-1) metribuzin, respectively.

Chromatography, High Pressure Liquid↗
PubMed2001

Determination of antifouling pesticides and their degradation products in marine sediments by means of ultrasonic extraction and HPLC-APCI-MS.

A method has been developed for the simultaneous determination of antifouling pesticides and some of their degradation products, e.g. dichlofluanid, diuron, demethyldiuron, 1-(3,4-dichlorophenyl)urea, sea-nine, Irgarol 1051 and one of its metabolites (2-methylthio-4-tert-butylamino-s-triazine) in marine sediments. The determination of these compounds in sediment samples was performed by means of methanolic ultrasonic extraction then clean-up on an Isolute ENV+ solid phase extraction (SPE) cartridge. The resulting extract was then analyzed by reversed-phase high-performance liquid chromatography coupled with atmospheric-pressure chemical-ionization mass spectrometry in negative and positive ion modes (HPLC-APCI-MS). Recovery ranged from 54-109% for the antifouling agents and their degradation products. The determination limits for the different compounds varied between 0.2 and 1.6 microg kg(-1) dry sediment. The analytical procedure was successfully applied to the determination of these pesticides and their degradation products in marine sediment samples from different marinas of the Catalan coast. The compounds detected were: diuron, dichlofluanid, demethyldiuron, sea-nine, and Irgarol 1051. The highest concentrations were those of diuron and Irgarol 1051--136 and 88 microg kg(-1), respectively.

Aniline Compounds↗
PubMed2001

An immunoassay for terbutryn using direct hapten linkage to a glutaraldehyde network on the polystyrene surface of standard microtiter plates.

2-Aminobutylamino-4-ethylamino-6-isopropylamino-1,3,5-triazine (ABA-atrazine) has been synthesized and used as a coating hapten in an immunoassay with a monoclonal antibody against terbutryn. Coating was achieved by covalently linking ABA-atrazine to a glutaraldehyde polymer network directly bound to the polystyrene surface of a standard 96-well microtiter plate. The assay was carefully optimized. In particular, the coating hapten concentration had a strong effect on the ELISA sensitivity. By including a pre-incubation step a low test midpoint (IC50-value) of 0.130 microg L(-1) was achieved. As far as we are aware this is the most sensitive ELISA for terbutryn yet reported. The coating-hapten-format presented is proposed as generally applicable, because the glutaraldehyde-modified microtiter plate surface enables stable immobilization of a broad variety of coating haptens.

Antibodies, Monoclonal↗
PubMed2003

Transplacental passage of lamotrigine in a human placental perfusion system in vitro and in maternal and cord blood in vivo.

OBJECTIVE: We studied transplacental passage of lamotrigine (3,5-diamino-6-[2,3-dichlorophenyl]-1,2,4-triazine; LTG) using an ex vivo human placental perfusion method and in in vivo samples. METHODS: Term placentas from healthy mothers without medications were perfused in a recirculating dual perfusion system. LTG (2.5 microg/ml, n=4; 10 microg/ml, n=4) and reference compound antipyrine (100 microg/ml) were added into the maternal circulation. The disappearance of drugs from the maternal circulation and appearance into the foetal circulation was followed every 15 min up to 2 h. Drug concentrations were analysed using high-performance liquid chromatography. In addition to human placental perfusions, we analysed LTG concentrations in maternal vein and cord blood samples after delivery from two epileptic mothers receiving LTG therapy during pregnancy. RESULTS: LTG was detectable in the foetal circulation at 15 min in all of the perfusions, indicating rapid transfer. Maternal and foetal concentrations reached equilibrium at 60 min with both concentrations used. The feto-maternal ratio was 1.26+/-0.20 with 10 microg/ml LTG and 0.83+/-0.41 with 2.5 microg/ml LTG at the end of the perfusion. The transfer of LTG from the maternal to the foetal compartment at 120 min was 28.9+/-10.7% with 2.5 microg/ml LTG and 37.8+/-3.2% with 10 microg/ml LTG (p>0.05). In the serum samples from epileptic mothers, the cord blood maternal concentration ratio was 1.02 in one pair and 1.55 in the other. CONCLUSIONS: LTG crossed the placenta easily and rapidly, indicating that the maternal treatment leads to a considerable foetal exposure.

Anticonvulsants↗
PubMed2003

Pregnancy and use of oral contraceptives reduces the biotransformation of proguanil to cycloguanil.

OBJECTIVE: To determine the effects of late pregnancy and also oestrogen supplementation on the CYP2C19-mediated biotransformation of proguanil (PG) to its active antifol triazine metabolite cycloguanil (CG). METHODS: Case control study conducted on the NW border of Thailand; a single dose of PG (4 mg/kg) was administered to Karen women in late pregnancy and a single blood and urine sample taken 6 h later. Women were studied in late pregnancy (>36 weeks) and restudied 2 months after delivery. A separate cohort of Karen women newly attending a birth-control clinic were studied before and 3 weeks into their first course of oral contraceptives (OCP: levonorgestrel 0.15 mg and ethinyloestradiol 0.03 mg). Forty-five pregnant women and forty-two healthy OCP users were studied. RESULTS: The results were similar in both groups; pregnancy and OCP use were both associated with reduced formation of cycloguanil (CG). Impaired PG biotransformation was seen in women with the "extensive metaboliser" phenotype (urine PG/CG ratio <10). CG levels, adjusted for dose, were a median (range) 73% (-59 to 420%) higher following the pregnancy than during the pregnancy in women characterised as extensive metabolisers ( P<0.001). CG levels in women characterised as extensive metabolisers were 34% (-54 to 323%) higher before than while taking the OCP ( P<0.01). CONCLUSION: Late pregnancy and OCP use impair biotransformation of the active antimalarial metabolite CG from the parent PG. This may be mediated by oestrogen inhibition of CYP2C19 activity. The dose of PG should be increased by 50% in these groups.

Antimalarials↗
PubMed2004

The binary treatment of aqueous metribuzin using anodic fenton treatment and biodegradation.

An advanced oxidation process, anodic Fenton treatment (AFT), and a mixed microbial culture were used to degrade metribuzin [4-amino-6-tert-butyl-3-methylthio-1,2,4- triazin-5(4H)-one], a broad-use triazinone herbicide. Complete and rapid removal of metribuzin was demonstrated. The appearance and subsequent degradation of metribuzin oxidation products--deaminated metribuzin (DA), diketo metribuzin (DK), as well as the production of deaminated diketo metribuzin (DADK)--were observed. To support the use of AFT as a chemical pretreatment, the ratio of 5-day biochemical oxygen demand (BOD5) as measured in the standard test to chemical oxygen demand (COD) was investigated, and an increase from 0.03, a nonbiodegradable solution, to 0.35, a biodegradable solution, was observed. This increase in biodegradability was associated with decreased metribuzin, DA, and DK concentrations and increased DADK concentration. AFT effluent was inoculated with either an enriched microbial culture or Polyseed, a commercially available inoculum. Although there was minimal biodegradation of the remaining metribuzin, there was a significant decrease in DA concentration in inoculated incubations compared with sterile controls after 5- and 10-minute AFT treatment. The enrichment inoculate appeared more adapted toward the less-oxidized, 5-minute-treated effluent, whereas the Polyseed culture, developed to degrade complex waste solutions, appeared to be more effective in a moreoxidized, 10-minute-treated, and potentially more complex effluent. This research supports the continued investigation of AFT and biodegradation as a binary treatment of aqueous pesticide wastes.

Agriculture↗
PubMed2006

Preliminary examination of short-term cellular toxicological responses of the coral Madracis mirabilis to acute Irgarol 1051 exposure.

Irgarol 1051 is an s-triazine herbicide formulated with Cu2O in antifouling paints. Recent studies have shown that Irgarol 1051 inhibits coral photosynthesis at environmentally relevant concentrations, consistent with its mode of action as a photosystem II inhibitor. Related toxicologic effects of this herbicide on coral cellular physiology have not yet been investigated. We used cellular diagnostics to measure changes in 18 toxicologic cellular parameters in endosymbiotic algal (dinoflagellate) and cnidarian (host) fractions of the common branching coral Madracis mirabilis associated with in vivo 8- and 24-hour exposures to a nominal initial Irgarol 1051 concentration of 10 microg L(-1). Responses measured were (1) xenobiotic response, which includes total and dinoflagellate multixenobiotic resistance (MXR), cnidarian cytochrome (CYP) P450-3 and P450-6 classes, cnidarian, and dinoflagellate glutathione-s-transferase (GST); (2) oxidative damage and response, which includes cnidarian and dinoflagellate Cu/Zn and Mn superoxide dismutase (SOD), cnidarian and dinoflagellate glutathione peroxidase (GPx), cnidarian catalase, and total protein carbonyl); (3) metabolic homeostasis, which includes chloroplast and invertebrate small heat-shock proteins (sHsp), cnidarian protoporphyrinogen oxidase IX (PPO), cnidarian ferrochelatase, and cnidarian heme oxygenase; and (4) protein metabolic condition, which includes cnidarian and dinoflagellate heat shock proteins (hsp70 and hsp60), total ubiquitin, and cnidarian ubiquitin ligase. Acute responses to Irgarol 1051 exposure included significant increases in total and dinoflagellate MXR, dinoflagellate Cu/Zn SOD, dinoflagellate chloroplast sHsp, and cnidarian PPO. Irgarol 1051 exposure resulted in decreases in cnidarian GPx, cnidarian ferrochelatase, cnidarian catalase, and cnidarian CYP 450-3 and -6 classes. Related implications of Irgarol 1051 exposure to coral cellular condition are discussed.

Animals↗
PubMed2000

Soil dissipation of diuron, chlorotoluron, simazine, propyzamide, and diflufenican herbicides after repeated applications in fruit tree orchards.

In a pear tree orchard planted on loam soil, each plot was treated in April 1998 with either one of the ureas diuron or chlorotoluron, or triazine simazine herbicides applied at 3, 4, and 2 kg AI ha(-1), respectively. Some plots had not been previously treated with one of these herbicides. Other plots had been treated annually during the past 12 years with the same herbicide. One herbicide, and always the same, was thus applied to each plot. In the plots treated for the first time with either diuron, chlorotoluron, or simazine, the soil half-lives of these herbicides in the 0-10 cm surface soil layer were 81, 64, and 59 days, respectively. In the plots treated with the same herbicide for 12 years, the corresponding soil half-lives were 37, 11, and 46 days. Diuron thus produced a moderately enhanced biodegradation, chlorotoluron a high one, and simazine a low but significant one. In another pear tree orchard planted on sandy loam soil, each plot was treated in April 1998 with one of the amide propyzamide (1.25 or 1.0 AI kg ha(-1)) or diflufenican (250 g AI ha(-1)) herbicides. In the plots not previously treated with propyzamide, the propyzamide soil half-life was the same for both doses, i.e., about 30 days. In the plots treated annually for 3 or 14 years with propyzamide, the soil half-life was 12 and 10 days, respectively. In the plots treated for the first time with diflufenican and in those treated annually with diflufenican for 3 years, the diflufenican soil half-life was the same, i.e., 65 days. Propyzamide thus already showed a highly accelerated biodegradation after 3 years of repeated annual applications. Diflufenican, however, did not show enhanced biodegradation after 3 years of repeated annual applications.

Fruit↗
PubMed2001

Development of marine toxicity data for ordnance compounds.

A toxicity database for ordnance compounds was generated using eight compounds of concern and marine toxicity tests with five species from different phyla. Toxicity tests and endpoints included fertilization success and embryological development with the sea urchin Arbacia punctulata; zoospore germination, germling length, and cell number with the green macroalga Ulva fasciata; survival and reproductive success of the polychaete Dinophilus gyrociliatus; larvae hatching and survival with the redfish Sciaenops ocellatus; and survival of juveniles of the opossum shrimp Americamysis bahia (formerly Mysidopsis bahia). The studied ordnance compounds were 2,4- and 2,6-dinitrotoluene, 2,4,6-trinitrotoluene, 1,3-dinitrobenzene, 1,3,5-trinitrobenzene, 2,4,6-trinitrophenylmethylnitramine (tetryl), 2,4,6-trinitrophenol (picric acid), and hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX). The most sensitive toxicity test endpoints overall were the macroalga zoospore germination and the polychaete reproduction tests. The most toxic ordnance compounds overall were tetryl and 1,3,5-trinitrobenzene. These were also the most degradable compounds, often being reduced to very low or below-detection levels at the end of the test exposure. Among the dinitro- and trinitrotoluenes and benzenes, toxicity tended to increase with the level of nitrogenation. Picric acid and RDX were the least toxic chemicals tested overall.

Animals↗
PubMed2000

Microbial degradation of explosives: biotransformation versus mineralization.

The nitroaromatic explosive 2,4,6-trinitrotoluene (TNT) is a reactive molecule that biotransforms readily under both aerobic and anaerobic conditions to give aminodinitrotoluenes. The resulting amines biotransform to give several other products, including azo, azoxy, acetyl and phenolic derivatives, leaving the aromatic ring intact. Although some Meisenheimer complexes, initiated by hydride ion attack on the ring, can be formed during TNT biodegradation, little or no mineralization is encountered during bacterial treatment. Also, although the ligninolytic physiological phase and manganese peroxidase system of fungi can cause some TNT mineralization in liquid cultures, little to no mineralization is observed in soil. Therefore, despite more than two decades of intensive research to biodegrade TNT, no biomineralization-based technologies have been successful to date. The non-aromatic cyclic nitramine explosives hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX) and octahydro-1,3,5,7-tetranitro-1,3,5,7-tetrazocine (HMX) lack the electronic stability enjoyed by TNT or its transformed products. Predictably, a successful enzymatic change on one of the N-NO2 or C-H bonds of the cyclic nitramine would lead to a ring cleavage because the inner C-N bonds in RDX become very weak (<2 kcal/mol). Recently this hypothesis was tested and proved feasible, when RDX produced high amounts of carbon dioxide and nitrous oxide following its treatment with either municipal anaerobic sludge or the fungus Phanaerocheate chrysosporium. Research aimed at the discovery of new microorganisms and enzymes capable of mineralizing energetic chemicals and/or enhancing irreversible binding (immobilization) of their products to soil is presently receiving considerable attention from the scientific community.

Aerobiosis↗
PubMed1998

Metabolism of explosive compounds by sulfate-reducing bacteria.

The metabolism of various explosive compounds-1,3,5-trinitrobenzene (TNB), hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX), and octahydro-1,3,5,7-tetranitro-1,3,5,7-tetraazocine (HMX)-by a sulfate-reducing bacterial consortium, Desulfovibrio spp., was studied. The results indicated that the Desulfovibrio spp. used all of the explosive compounds studied as their sole source of nitrogen for growth. The concentrations of TNB, RDX, and HMX in the culture media dropped to below the detection limit (<0.5 ppm) within 18 days of incubation. We also observed the production of ammonia from the nitro groups of the explosive compounds in the culture media. This ammonia served as a nitrogen source for the bacterial growth, and the concentration of ammonia later dropped to <0.5 mg/L. The sulfate-reducing bacteria may be useful in the anaerobic treatment of explosives-contaminated soil.

Ammonia↗
PubMed2000

Use of fluorescently labelled calmodulins as tools to measure subcellular calmodulin activation in living dorsal root ganglion cells.

We have used fluorescently labelled calmodulins to probe the activity of calmodulin in living dorsal root ganglion cells. Calmodulin labelled with the fluorophore 5-([4,6 dichlorotriazin-2yl]amino)-fluorescein (FL-CaM) does not change its fluorescence when it binds calcium, while calmodulin labelled at lysine 75 with 2-chloro-(6-(4-N,N-diethylamino-phenyl)-1,4,5-triazin-4-yl (TA-CaM), an environment-sensitive probe, increases its fluorescence when it binds calcium. We micro-injected FL-CaM or TA-CaM into rat dorsal root ganglion cells and found that both probes localise to the cell nucleus. In contrast, endogenous cellular calmodulin, in dorsal root ganglion cells as in hippocampal neurones, is predominantly cytosolic unless the neurones are depolarised, then it moves to the nucleus. FL-CaM and TA-CaM, introduced into dorsal root ganglion cells via a patch pipette, also immediately move to the nucleus, indicating that the nuclear localisation is a property of the labelled calmodulins. Although the subcellular distribution of FL-CaM and TA-CaM does not necessarily match that of endogenous calmodulin, we show that FL-CaM can be used as a control for TA-CaM when studying calmodulin activation in different cellular compartments.

Animals↗
PubMed2003

Characterization of a novel cellulose synthesis inhibitor.

The physiological effects of an experimental herbicide and cellulose synthesis inhibitor, N2-(1-ethyl-3-phenylpropyl)-6-(1-fluoro-1-methylethyl)-1,3,5-triazine-2,4-diamine, called AE F150944, are described. In the aminotriazine molecular class, AE F150944 is structurally distinct from other known cellulose synthesis inhibitors. It specifically inhibits crystalline cellulose synthesis in plants without affecting other processes that were tested. The effects of AE F150944 on dicotyledonous plants were tested on cultured mesophyll cells of Zinnia elegans L. cv. Envy, which can be selectively induced to expand via primary wall synthesis or to differentiate into tracheary elements via secondary wall synthesis. The IC50 values during primary and secondary wall synthesis in Z. elegans were 3.91 x 10(-8) M and 3.67 x 10(-9) M, respectively. The IC50 in suspension cultures of the monocot Sorghum halapense (L.) Pers., which were dividing and synthesizing primary walls, was 1.67 x 10(-10) M. At maximally inhibitory concentrations, 18-33% residual crystalline cellulose synthesis activity remained, with the most residual activity observed during primary wall synthesis in Z. elegans. Addition to Z. elegans cells of two other cellulose synthesis inhibitors, 1 microM 2,6-dichlorobenzonitrile and isoxaben, along with AE F150944 did not eliminate the residual cellulose synthesis, indicating little synergy between the three inhibitors. In differentiating tracheary elements, AE F150944 inhibited the deposition of detectable cellulose into patterned secondary wall thickenings, which was correlated with delocalization of lignin as described previously for 2, 6-dichlorobenzonitrile. Freeze-fracture electron microscopy showed that the plasma membrane below the patterned thickenings of AE F150944-treated tracheary elements was depleted of cellulose-synthase-containing rosettes, which appeared to be inserted intact into the plasma membrane followed by their rapid disaggregation. AE F150944 also inhibited cellulose-dependent growth in the rosette-containing alga, Spirogyra pratensis, but it did not inhibit cellulose synthesis in Acetobacter xylinum or Dictyostelium discoideum, both of which synthesize cellulose via linear terminal complexes. Therefore, AE F150944 may inhibit crystalline cellulose synthesis by destabilizing plasma membrane rosettes.

Asteraceae↗
PubMed2005

White biotechnology for green chemistry: fermentative 2-oxocarboxylic acids as novel building blocks for subsequent chemical syntheses.

Functionalized compounds, which are difficult to produce by classical chemical synthesis, are of special interest as biotechnologically available targets. They represent useful building blocks for subsequent organic syntheses, wherein they can undergo stereoselective or regioselective reactions. "White Biotechnology" (as defined by the European Chemical Industry [ http://www.europabio.org/white_biotech.htm ], as part of a sustainable "Green Chemistry,") supports new applications of chemicals produced via biotechnology. Environmental aspects of this interdisciplinary combination include: Use of renewable feedstock Optimization of biotechnological processes by means of: New "high performance" microorganisms On-line measurement of substrates and products in bioreactors Alternative product isolation, resulting in higher yields, and lower energy demand In this overview we describe biotechnologically produced pyruvic, 2-oxopentaric and 2-oxohexaric acids as promising new building blocks for synthetic chemistry. In the first part, the microbial formation of 2-oxocarboxylic acids (2-OCAs) in general, and optimization of the fermentation steps required to form pyruvic acid, 2-oxoglutaric acid, and 2-oxo-D-gluconic acid are described, highlighting the fundamental advantages in comparison to chemical syntheses. In the second part, a set of chemical formula schemes demonstrate that 2-OCAs are applicable as building blocks in the chemical synthesis of, e.g., hydrophilic triazines, spiro-connected heterocycles, benzotriazines, and pyranoic amino acids. Finally, some perspectives are discussed.

Biotechnology↗
PubMed2005

Quantitative assessment of heteroplasmy levels in Senecio vulgaris chloroplast DNA.

Heteroplasmy in coding chloroplast DNA was only recently shown to occur and was so far not quantitatively assessed. We present a quantitative analysis of cpDNA heteroplasmy levels at a triazine-resistance determining site within and between individual Senecio vulgaris plants. Detectable levels of heteroplasmic haplotypes were observed in all tested plants. As expected, the levels of heteroplasmy vary greatly between plants. However, even within individual plants, the fraction of one haplotype may cover a range from below 1% to well over 90%. Our results suggest that heteroplasmy may be a common phenomenon in S. vulgaris. Possible consequences for molecular diagnostics of chloroplast encoded traits as well as evolutionary consequences of chloroplast heteroplasmy are discussed.

DNA, Chloroplast↗