Pitfalls in the Detection of Volatiles Associated with Heated Tobacco and e-Vapor Products When Using PTR-TOF-MS.

We investigated the applicability of proton transfer reaction-time-of-flight mass spectrometry (PTR-TOF-MS) for quantitative analysis of mixtures comprising glycerin, acetol, glycidol, acetaldehyde, acetone, and propylene glycol. While PTR-TOF-MS offers real-time simultaneous determination, the method selectivity is limited when analyzing compounds with identical elemental compositions or when labile compounds present in the mixture produce fragments that generate overlapping ions with other matrix components. In this study, we observed significant fragmentation of glycerin, acetol, glycidol, and propylene glycol during protonation via hydronium ions (H3O+). Nevertheless, specific ions generated by glycerin (m/z 93.055) and propylene glycol (m/z 77.060) enabled their selective detection. To thoroughly investigate the selectivity of the method, various mixtures containing both isotope-labeled and unlabeled compounds were utilized. The experimental findings demonstrated that when samples contained high levels of glycerin, it was not feasible to perform time-resolved analysis in H3O+ mode for acetaldehyde, acetol, and glycidol. To overcome the observed selectivity limitations associated with the H3O+ reagent ions, alternative ionization modes were investigated. The ammonium ion mode proved appropriate for analyzing propylene glycol (m/z 94.086) and acetone (m/z 76.076) mixtures. Concerning the nitric oxide mode, specific m/z were identified for acetaldehyde (m/z 43.018), acetone (m/z 88.039), glycidol (m/z 73.028), and propylene glycol (m/z 75.044). It was concluded that considering the presence of multiple product ions and the potential influence of other compounds, it is crucial to conduct a thorough selectivity assessment when employing PTR-TOF-MS as the sole method for analyzing compounds in complex matrices of unknown composition.

Analysis of potential phenylacetone precursors (ethyl 3-oxo-2-phenylbutyrate, methyl 3-oxo-4-phenylbutyrate, and ethyl 3-oxo-4-phenylbutyrate) by gas chromatography/mass spectrometry and their conversion to phenylacetone.

Methyl 3-oxo-2-phenylbutyrate (MAPA) is a recently circulating precursor of phenylacetone (P2P), a precursor of amphetamine and methamphetamine. MAPA has a hybrid chemical structure of acetoacetic acid ester and P2P. Acetoacetic acid ester is de-esterified and decarboxylated to give the ketone by heating under acidic conditions; therefore, MAPA is presumed to be converted to P2P by such treatment. Considering that ethyl 3-oxo-2-phenylbutyrate (EAPA), methyl 3-oxo-4-phenylbutyrate (MGPA), and ethyl 3-oxo-4-phenylbutyrate (EGPA) have the same chemical features as MAPA, these three compounds are potential P2P precursors. The authors examined the analysis of these compounds by gas chromatography-mass spectrometry (GC-MS) and their conversion to P2P by heating under acidic and basic conditions. These compounds were remarkably decomposed into P2P during GC-MS analysis regardless of the injection method and injector temperature. EAPA and EGPA also caused ester exchange to methyl ester by injection of methanol solution. P2P production and transesterification were almost prevented by methoxime derivatization. These compounds were converted to P2P by heating under acidic conditions. The reaction of MGPA and EGPA proceeded quicker than that of EAPA. The important by-product associated with the reaction was phenylacetylcarbinol (formed from EAPA and MGPA), which will be converted to (pseudo)ephedrine, important methamphetamine impurities. By heating under basic conditions, MGPA and EGPA were converted to P2P but EAPA was mainly converted to phenylacetic acid. In the future, when these compounds are in circulation, our study will be useful for identifying and elucidating the synthetic method of P2P.

Lernaea cyprinacea Linnaeus, 1758 (Copepoda: Lernaeidae) infection on Betta rubra Perugia, 1893 (Anabantiformes: Osphronemidae) from Aceh Province, Indonesia / Infecção por Lernaea cyprinacea Linnaeus, 1758 (Copepoda: Lernaeidae) em Betta rubra Perugia, 1893 (Anabantiformes: Osphronemidae) provenientes da província de Aceh, Indonésia

Abstract Betta rubra is an ornamental freshwater fish endemic to northern Sumatra, Indonesia. The B. rubra population has decreased in recent decades, and is classified as an endangered species in the IUCN Red List. This study aims to report for the first time infection by L. cyprinacea in B. rubra harvested from the Aceh Besar region of Indonesia. The fish samples were obtained from the Cot Bira tributaries, Aceh Besar District, Indonesia from January to December 2020. The results showed that the parasite infected 6 out of 499 samples in August and September, with a prevalence and intensity rate of 1% and 2 parasites/fish, respectively. The eyes and pectoral fins were the common infection sites. Despite B. rubra is not an optimal host (small size) for the parasite, this parasite might serve as additional threatening factors for the endangered B. rubra fish population.

Resumo Betta rubra é um peixe de água doce ornamental endemico da região norte Sumatra, Indonesia. A população de Betta rubra diminuiu ao longo dos anos, sendo classificada como espécie em extinção na Lista Vermelha da IUCN. Este estudo tem como objetivo relatar pela primeira vez infecção por L. cyprinacea em B. rubra coletados na região de Aceh Besar na Indonésia. As amostras de peixes foram obtidas nos afluentes Cot Bira, distrito de Aceh Besar, Indonésia de janeiro a dezembro de 2020. Os resultados mostraram que o parasito infectou 6 das 499 amostras em agosto e setembro, com uma prevalência e taxa de intensidade de 1% e 2 parasitas/peixes, respectivamente. Os olhos e as nadadeiras peitorais foram os sítios de infecção mais comuns. Apesar de B. rubra não ser um hospedeiro ideal (pequeno tamanho) para o parasita, este parasita pode servir como fator de ameaça adicional para a população de peixes B. rubra, ameaçada de extinção.

Evolution of a Novel and Adaptive Floral Scent in Wild Tobacco.

Many plants emit diverse floral scents that mediate plant-environment interactions and attain reproductive success. However, how plants evolve novel and adaptive biosynthetic pathways for floral volatiles remains unclear. Here, we show that in the wild tobacco, Nicotiana attenuata, a dominant species-specific floral volatile (benzyl acetone, BA) that attracts pollinators and deters florivore is synthesized by phenylalanine ammonia-lyase 4 (NaPAL4), isoflavone reductase 3 (NaIFR3), and chalcone synthase 3 (NaCHAL3). Transient expression of NaFIR3 alone in N. attenuata leaves is sufficient and necessary for ectopic foliar BA emissions, and coexpressing NaIFR3 with NaPAL4 and NaCHAL3 increased the BA emission levels. Independent changes in transcription of NaPAL4 and NaCHAL3 contributed to intraspecific variations of floral BA emission. However, among species, the gain of expression of NaIFR3 resulted in the biosynthesis of BA, which was only found in N. attenuata. This study suggests that novel metabolic pathways associated with adaptation can arise via reconfigurations of gene expression.

Determination of New Psychoactive Substances in Whole Blood Using Microwave Fast Derivatization and Gas Chromatography/Mass Spectrometry.

The production and consumption of new psychoactive substances (NPSs) has been raising a major concern worldwide. Due to easy access and available information, many NPSs continue to be synthesized with an alarming increase of those available to purchase, despite all the control efforts created. A new analytical method was developed and validated to determine a group of phenethylamines and synthetic cathinones: cathinone, flephedrone, buphedrone, 4-MTA, α-PVP, methylone, 2C-P, ethylone, pentylone, MDPV and bromo-dragonFLY in whole blood. A mixed-mode solid phase extraction was applied to 250 µL of sample, and the extracts were derivatized with fast microwave technique before being analyzed by gas chromatography-mass spectrometry (GC-MS). The validation procedure followed the Scientific Working Group for Forensic Toxicology (SWGTOX) guidelines with parameters that included selectivity, linearity, limits of detection and quantification, intra- and inter-day precision and accuracy, recoveries and stability. The method presented linearity between 5 and 500 ng/mL for cathinone, buphedrone, 4-MTA, methylone, 2C-P and bromo-dragonFLY, 10-500 ng/mL for flephedrone, ethylone, pentylone and MDPV, and 40-500 ng/mL for α-PVP, with determination coefficients above 0.99 for all analytes. Recoveries ranged between 70.3% and 116.6%, and regarding intra- and inter-day precision, the relative mean errors were typically lower than 8.6%. The method was successfully applied to over 100 authentic samples from the Laboratory of Chemistry and Forensic Toxicology, Centre Branch, of the National Institute of Legal Medicine and Forensic Sciences, Portugal.

Effect of Nutrition Education and Multi-Nutrient Biscuit Interventions on Nutritional and Iron Status: A Cluster Randomized Control Trial on Undernourished Children Aged 6-23 Months in Aceh, Indonesia.

Undernutrition and iron deficiencies on under-five children in Indonesia remain high and very closely related to inadequate complementary feeding. This study investigated the effect of weekly nutrition education by home visite using the food monitoring card (FMC) models and daily provision multi-nutrient biscuits and combination on growth and reduction of iron deficiency and anemia among underweight children aged 6-23 mo in Aceh Indonesia. A 6-mo, cluster randomized, control trial was conducted on 121 children received nutrition education (NE), multi-nutrient biscuit (MNB), combination both nutrition education and biscuits (NE+MNB), and control group. The outcome weight gain and prevalence of underweight (weight for age z-score <-2SD) were collected by anthropometric and iron deficiency were serum ferritin measuring with ELISA method. After the 6-mo intervention, the rate of weight gain was higher in combination intervention group 1.51±0.68 kg than multi-biscuit group 1.40±0.72 kg, NE group 1.34±0.66 kg and control group 1.21±0.42 kg, and the rate increase of serum ferritin was higher in combination NE+MNB and biscuit group (2.54 µg/L and 2,17 µg/L). At the end of study there were a significant decrease in prevalence of underweight (p=0.003), the incidence of underweight in NE+MNB (45.2%) lower than NE group (63.3%), MNB group (64.5%) and control group (69,0%) and significant decrease of iron deficiency (p=0.02), the incidence lower in MNB group (6.5%) than NE+MNB (22.6%), NE group (23.3%) and control group (24.1%). The combination of nutritional education and multi-nutrient biscuits intervention improving nutritional and iron deficiency status on undernourished children. These risearch highlight the need integration of nutrition education and food base intervention to prevent underweight and iron deficiency on children 6-23 mo old.

Side-Chain Dynamics of the Trifluoroacetone Cysteine Derivative Characterized by 19F NMR Relaxation and Molecular Dynamics Simulations.

19F NMR spectroscopy is a powerful tool for the study of the structures, dynamics, and interactions of proteins bearing cysteine residues chemically modified with a trifluoroacetone group (CYF residue). 19F NMR relaxation rates for the fluoromethyl group of CYF residues are sensitive to overall rotational tumbling of proteins, fast rotation about the CF3 methyl axis, and the internal motion of the CYF side-chain. To develop a quantitative understanding of these various motional contributions, we used the model-free approach to extend expressions for 19F- T2 NMR relaxation to include side-chain motions for the CYF residue. We complemented the NMR studies with atomic views of methyl rotation and side-chain motions using molecular dynamics simulations. This combined methodology allows for quantitative separation of the contributions of fast pico- to nanosecond dynamics from micro- to millisecond exchange processes to the 19F line width and highlights the utility of the CYF residue as a sensitive reporter of side-chain environment and dynamics in proteins.

Discrimination between chewing of coca leaves or drinking of coca tea and smoking of "paco" (coca paste) by hair analysis. A preliminary study of possibilities and limitations.

BACKGROUND: Hair analysis is a suitable way to discriminate between coca chewers and consumers of manufactured cocaine using the coca alkaloids hygrine (HYG) and cuscohygrine (CUS) as markers. In the present preliminary study it was examined whether CUS and HYG can be detected in hair of occasional and moderate coca chewers or coca tea drinkers, whether CUS and HYG appear in hair of PACO consumers (smoking coca paste waste), and whether anhydroecgonine methyl ester (AEME) is a useful cocaine smoking marker in this context. METHOD: Three groups were included: 10 volunteers from Buenos Aires with occasional or moderate chewing of coca leaves or drinking coca tea, 20 Argentinean PACO smokers and 8 German cocaine users. The hair samples (1-4 segments) were analyzed by a validated LC-MS/MS method for cocaine (COC), norcocaine (NC), benzoylecgonine (BE), ecgonine methyl ester (EME), cocaethylene (CE), cinnamoylcocaine (CIN), tropacocaine (TRO), AEME, CUS and HYG. For comparison, eight samples of coca leaves or coca tea were analyzed. RESULTS: Only low concentrations of COC were found in hair of seven occasional users of coca leaves or coca tea (0.010-0.051 ng/mg). For three moderate chewers of coca leaves all compounds were detected including AEME but except TRO. The hair samples of PACO smokers contained much higher concentrations of COC (0.027-341 ng/mg, mean 37.4 ng/mg) and its metabolites. CUS was not found in these samples but traces of HYG were seen in 8 of 37 hair segments. AEME as a marker for coca smoking was detected in hair of 15 smokers. In comparison to COC, the concentrations of EME and CIN were higher for PACO smokers than for German cocaine consumers. AEME (56 ± 20 µg/g) was detected in all coca leave and coca tea samples which explains the detection of this substance in hair of coca chewers. Therefore, its use for differentiation between coca chewers and PACO smokers is limited. CONCLUSION: CUS remains to be the most suitable marker in hair for chewing coca leaves or drinking coca tea more frequently than two times per month since it does not appear in hair of Argentinean PACO smokers and German cocaine users. Contrary to a previous proposal, the ratios CIN/COC and EME/COC appeared not to be applicable as criteria for this purpose because of the higher concentration of these alkaloids in hair of PACO smokers. More research is needed to assess the value of AEME in hair of South American coca leave or cocaine users.

Structural and kinetic characterization of (S)-1-amino-2-propanol kinase from the aminoacetone utilization microcompartment of Mycobacterium smegmatis.

Bacterial microcompartments encapsulate enzymatic pathways that generate small, volatile, aldehyde intermediates. The Rhodococcus and Mycobacterium microcompartment (RMM) operon from Mycobacterium smegmatis encodes four enzymes, including (S)-1-amino-2-propanol dehydrogenase and a likely propionaldehyde dehydrogenase. We show here that a third enzyme (and its nonmicrocompartment-associated paralog) is a moderately specific (S)-1-amino-2-propanol kinase. We determined the structure of apo-aminopropanol kinase at 1.35 Å, revealing that it has structural similarity to hexosamine kinases, choline kinases, and aminoglycoside phosphotransferases. We modeled substrate binding, and tested our model by characterizing key enzyme variants. Bioinformatics analysis established that this enzyme is widespread in Actinobacteria, Proteobacteria, and Firmicutes, and is very commonly associated with a candidate phospholyase. In Rhizobia, aminopropanol kinase is generally associated with aromatic degradation pathways. In the RMM (and the parallel pathway that includes the second paralog), aminopropanol kinase likely degrades aminoacetone through a propanolamine-phosphate phospho-lyase-dependent pathway. These enzymatic activities were originally described in Pseudomonas, but the proteins responsible have not been previously identified. Bacterial microcompartments typically co-encapsulate enzymes which can regenerate required co-factors, but the RMM enzymes require four biochemically distinct co-factors with no overlap. This suggests that either the RMM shell can uniquely transport multiple co-factors in stoichiometric quantities, or that all enzymes except the phospho-lyase reside outside of the shell. In summary, aminopropanol kinase is a novel enzyme found in diverse bacteria and multiple metabolic pathways; its presence in the RMM implies that this microcompartment degrades aminoacetone, using a pathway that appears to violate some established precepts as to how microcompartments function.

Structure and Kinetics of the S-(+)-1-Amino-2-propanol Dehydrogenase from the RMM Microcompartment of Mycobacterium smegmatis.

S-(+)-1-Amino-2-propanol dehydrogenase (APDH) is a short-chain dehydrogenase/reductase associated with the incompletely characterized Rhodococcus and Mycobacterium bacterial microcompartment (RMM). We enzymatically characterized the APDH from M. smegmatis and showed it is highly selective, with a low micromolar Km for S-(+)-1-amino-2-propanol and specificity for NADP(H). A paralogous enzyme from a nonmicrocompartment-associated operon in the same organism was also shown to have a similar activity. We determined the structure of APDH in both apo form (at 1.7 Å) and as a ternary enzyme complex with NADP+ and aminoacetone (at 1.9 Å). Recognition of aminoacetone was mediated by strong hydrogen bonds to the amino group by Thr145 and by Glu251 from the C-terminus of an adjacent protomer. The substrate binding site entirely encloses the substrate, with close contacts between the aminoacetone methyl group and Phe95, Trp154, and Leu195. Kinetic characterization of several of these residues confirm their importance in enzyme functioning. Bioinformatics analysis of APDH homologues implies that many nonmicrocompartment APDH orthologues partake in an aminoacetone degradation pathway that proceeds via an aminopropanol O-phosphate phospholyase. RMM microcompartments may mediate a similar pathway, though possibly with differences in the details of the pathway that necessitates encapsulation behind a shell.

The production of formaldehyde and hydroxyacetone in methacrolein photooxidation: New insights into mechanism and effects of water vapor.

Methacrolein (MACR) is an abundant multifunctional carbonyl compound with high reactivity in the atmosphere. In this study, we investigated the hydroxyl radical initiated oxidation of MACR at various NO/MACR ratios (0 to 4.04) and relative humidities (<3% to 80%) using a flow tube. Meanwhile, a box model based on the Master Chemical Mechanism was performed to test our current understanding of the mechanism. In contrast to the reasonable predictions for hydroxyacetone production, the modeled yields of formaldehyde (HCHO) were twice higher than the experimental results. The discrepancy was ascribed to the existence of unconsidered non-HCHO forming channels in the chemistry of CH3C(CH2)OO, which account for approx. 50%. In addition, the production of hydroxyacetone and HCHO were affected by water vapor as well as the initial NO/MACR ratio. The yields of HCHO were higher under humid conditions than that under dry condition. The yields of hydroxyacetone were higher under humid conditions at low-NOx level, while lower at high-NOx level. The reasonable explanation for the lower hydroxyacetone yield under humid conditions at high-NOx level is that water vapor promotes the production of methacrolein nitrate in the reaction of HOCH2C(CH3)(OO)CHO with NO due to the peroxy radical-water complex formation, which was evidenced by calculational results. And the minimum equilibrium constant of this water complex formation was estimated to be 1.89×10-18cm3/molecule. These results provide new insights into the MACR oxidation mechanism and the effects of water vapor.

Jasmonate signaling makes flowers attractive to pollinators and repellant to florivores in nature.

Flowers are required for the Darwinian fitness of flowering plants, but flowers' advertisements for pollination services can attract florivores. Previous glasshouse work with Nicotiana attenuata revealed the role of jasmonate (JA) signaling in flower development, advertisement and defense. However, whether JA signaling mediates flowers' filtering of floral visitors in nature remained unknown. This field study revealed that silencing JA signaling resulted in flowers that produce less nectar and benzyl acetone, two pollinator-attractive traits. Meanwhile, flowers of defenseless plants were highly attacked by a suite of native herbivores, and damage to buds in native plants correlated negatively with their JA-Ile levels.

Behaviour of hygrine and cuscohygrine in illicit cocaine production establishes their use as markers for chewing coca leaves in contrast with cocaine abuse.

Hygrine (HYG) and cuscohygrine (CUS) are natural alkaloids of coca leaves but are not found in illicit cocaine seizures. Therefore, they were proposed as markers for coca chewing in contrast to cocaine abuse in urine and hair testing. In order to examine at which step of the illegal cocaine production these compounds are lost, coca leaves were processed according to an authentic procedure by extraction with lime and kerosene, re-extraction with sulphuric acid, and precipitation of coca paste with ammonia. Non-extracted and extracted coca leaves, acidic extract and coca paste were analyzed by gas chromatography-mass spectrometry (GC-MS) and liquid chromatography-tandem mass spectrometry (LC-MS/MS) for cocaine, ecgonine methyl ester (EME), cinnamoylcocaine (CIN), HYG, and CUS. It follows from the results that under these conditions, HYG and CUS are extracted only to a minor extent by kerosene and are not precipitated from the acidic re-extract in the coca paste. Due to this behaviour in illegal cocaine production, they fulfil the conditions as markers for coca chewing in an optimal way. However, for unambiguous discrimination between coca chewing and cocaine abuse in human samples, additional markers of manufactured cocaine are required. Copyright © 2016 John Wiley & Sons, Ltd.

Synthesis, Molecular Structure Optimization, and Cytotoxicity Assay of a Novel 2-Acetyl-3-amino-5-[(2-oxopropyl)sulfanyl]-4-cyanothiophene.

A novel thiophene-containing compound, 2-acetyl-3-amino-5-[(2-oxopropyl)sulfanyl]-4-cyanothiophene (4) was synthesized by reaction of malononitrile with CS2 in the presence of K2CO3 under reflux in DMF and the subsequent reaction with chloroacetone followed by cyclization. This compound has been characterized by means of FT-IR, ¹H-NMR, (13)C-NMR, and mass spectrometry as well as elemental analysis. In addition, the molecular structures of compound 4 was determined by X-ray crystallography. The geometry of the molecule is stabilized by an intramolecular interaction between N1-H1···O1 to form S6 graf set ring motif. In the crystal, molecules are linked via N1-H2···O1 and C7-H7A···N2 interactions to form a three-dimensional network. Molecular structure and other spectroscopic properties of compound 4 were calculated using DFT B3LYP/6-31G (d,p) method. Results revealed a good agreement between the optimized geometric parameters and the observed X-ray structure. Furthermore, and by employing the natural bond orbital (NBO) method, the intramolecular charge transfer (ICT) interactions along with natural atomic charges at different sites, were calculated; results indicated strong n→π* ICT from LP(1)N5→BD*(2)C15-C16 (63.23 kcal/mol). In addition, the stabilization energy E(2) of the LP(2)O3→ BD*(1)N5-H6 ICT (6.63 kcal/mol) indicated the presence of intramolecular N-H···OH bonding. Similarly, calculations of the electronic spectra of compound 4 using, TD-DFT revealed a good agreement with the experimental data. Finally, compound 4 was evaluated for its in vitro cytotoxic effect against PC-3 and HeLa cell lines, as an anticancer agent, and found to be nontoxic.

Occurrence and health risk assessment of halogenated disinfection byproducts in indoor swimming pool water.

Swimming pool disinfection byproducts (DBPs) have become a concern in many countries all over the world. In this study, the concentrations of several categories of DBPs, including trihalomethanes (THMs), haloacetic acids (HAAs), haloacetonitriles (HANs), haloketones (HKs) and trichloronitromethane (TCNM), in 13 public indoor swimming pools in Nanjing, China were determined, the correlations between DBPs and water quality parameters as well as between different DBP categories were evaluated, and the health risks of the DBPs to human were examined. The results indicate that the DBP levels in the swimming pools in Nanjing were relatively high, with HAAs as the most dominant category, followed by THMs, HANs, HKs and TCNM sequentially. Bromochloroacetic acid (BCAA), trichloromethane (TCM), dichloroacetonitrile (DCAN), and 1,1,1-trichloropropanone (1,1,1-TCP) were the most dominant species among HAAs, THMs, HANs, and HKs, respectively. For all the different categories of DBPs, the concentrations in the pool disinfected with ozonation/chlorination were lower than those in the pool disinfected with chlorination. The DBP levels were generally not affected by the number of swimmers and the DBP levels on different dates were relatively stable. Besides, the chlorine residual seemed to be a critical concern in most of the swimming pools in this study. Moreover, there were some correlations between DBPs and water quality parameters as well as between different DBP categories. It is to be noted that the predicted cancer and health risks of the DBPs in these swimming pools were generally higher than the regulatory limits by USEPA, and thus DBPs in these swimming pools should be concerned.

Determination of Synthetic Cathinones in Urine Using Gas Chromatography-Mass Spectrometry Techniques.

In recent years, the abuse of synthetic cathinones has increased considerably. This study proposes a method, based on gas chromatography/mass spectrometry (GC-MS), to analyze and quantify six synthetic cathinones in urine samples: mephedrone (4-MMC), methylone (bk-MDMA), butylone, ethylone, pentylone and methylenedioxypyrovalerone (MDPV). In our procedure, the urine samples undergo solid-phase extraction (SPE) and derivatization prior to injection into the GC-MS device. Separation is performed using a HP-5MS capillary column. The use of selective ion monitoring (SIM mode) makes it is good sensitivity in this method, and the entire analysis process is within 18 min. In addition, the proposed method maintains linearity in the calibration curve from 50 to 2,000 ng/mL (r(2) > 0.995). The limit of detection of this method is 5 ng/mL, with the exception of MDPV (20 ng/mL); the limit of quantification is 20 ng/mL, with the exception of MDPV (50 ng/mL). In testing, the extraction performance of SPE was between 82.34 and 104.46%. Precision and accuracy results were satisfactory <15%. The proposed method was applied to six real urine samples, one of which was found to contain 4-MMC and bk-MDMA. Our results demonstrate the efficacy of the proposed method in the identification of synthetic cathinones in urine, with regard to the limits of detection and quantification. This method is highly repeatable and accurate.

Pharmacological activation of endogenous protective pathways against oxidative stress under conditions of sepsis.

BACKGROUND: Mitochondrial oxidative stress has a role in sepsis-induced organ dysfunction. The endogenous mechanisms to initiate protective pathways are controlled by peroxisome proliferator-activated receptor gamma co-activator 1-alpha (PGC1α) and nuclear factor erythroid 2-like 2 (NFE2L2). Activation of these pathways are potential therapeutic targets in sepsis. We used pharmacological activators to determine the effects on markers of mitochondrial damage and inflammation in human endothelial cells under conditions of sepsis. METHODS: Human endothelial cells were exposed to lipopolysaccharide plus peptidoglycan G to mimic a sepsis environment, with a range of concentrations of a selective synthetic agonist of silent information regulator-1 (SIRT-1) which activates PGC1α, or bis(2-hydroxy-benzylidene) acetone (2HBA) which activates NFE2L2, with and without inhibitors of these pathways. Cells were cultured for up to seven days and we measured mitochondrial membrane potential, metabolic activity, and density (as a marker of biogenesis), interkeukin-6 (to reflect inflammation) and glutathione (as a measure of antioxidant status). RESULTS: Under conditions mimicking sepsis, activation of the PGC1α and NFE2L2 pathways protected cells from LPS/PepG-induced loss of mitochondrial membrane potential (P=0.0002 and P=0.0009, respectively) and metabolic activity (P=0.05 and P<0.0001, respectively), and dampened interleukin-6 responses (P=0.003 and P=0.0001, respectively). Mitochondrial biogenesis (both P=0.0001) and glutathione (both P<0.0001) were also increased. These effects were blunted by the respective inhibitors. CONCLUSIONS: The development of organ dysfunction during human sepsis is linked to mitochondrial dysfunction, and so activation of PGC1α/NFE2L2 is likely to be beneficial. These pathways are attractive therapeutic targets for sepsis.

Application of acetone acetals as water scavengers and derivatization agents prior to the gas chromatographic analysis of polar residual solvents in aqueous samples.

The sensitivity of gas chromatography (GC) combined with the full evaporation technique (FET) for the analysis of aqueous samples is limited due to the maximum tolerable sample volume in a headspace vial. Using an acetone acetal as water scavenger prior to FET-GC analysis proved to be a useful and versatile tool for the analysis of high boiling analytes in aqueous samples. 2,2-Dimethoxypropane (DMP) was used in this case resulting in methanol and acetone as reaction products with water. These solvents are relatively volatile and were easily removed by evaporation enabling sample enrichment leading to 10-fold improvement in sensitivity compared to the standard 10µL FET sample volumes for a selection of typical high boiling polar residual solvents in water. This could be improved even further if more sample is used. The method was applied for the determination of residual NMP in an aqueous solution of a cefotaxime analogue and proved to be considerably better than conventional static headspace (sHS) and the standard FET approach. The methodology was also applied to determine trace amounts of ethylene glycol (EG) in aqueous samples like contact lens fluids, where scavenging of the water would avoid laborious extraction prior to derivatization. During this experiment it was revealed that DMP reacts quantitatively with EG to form 2,2-dimethyl-1,3-dioxolane (2,2-DD) under the proposed reaction conditions. The relatively high volatility (bp 93°C) of 2,2-DD makes it possible to perform analysis of EG using the sHS methodology making additional derivatization reactions superfluous.

Catalytic function of the mycobacterial binuclear iron monooxygenase in acetone metabolism.

Mycobacteria such as Mycobacterium smegmatis strain mc(2)155 and Mycobacterium goodii strain 12523 are able to grow on acetone and use it as a source of carbon and energy. We previously demonstrated by gene deletion analysis that the mimABCD gene cluster, which encodes a binuclear iron monooxygenase, plays an essential role in acetone metabolism in these mycobacteria. In the present study, we determined the catalytic function of MimABCD in acetone metabolism. Whole-cell assays were performed using Escherichia coli cells expressing the MimABCD complex. When the recombinant E. coli cells were incubated with acetone, a product was detected by gas chromatography (GC) analysis. Based on the retention time and the gas chromatography-mass spectrometry (GC-MS) spectrum, the reaction product was identified as acetol (hydroxyacetone). The recombinant E. coli cells produced 1.02 mM of acetol from acetone within 24 h. Furthermore, we demonstrated that MimABCD also was able to convert methylethylketone (2-butanone) to 1-hydroxy-2-butanone. Although it has long been known that microorganisms such as mycobacteria metabolize acetone via acetol, this study provides the first biochemical evidence for the existence of a microbial enzyme that catalyses the conversion of acetone to acetol.

How to get the best deal.

Floral scents and nectar attract both pollinators and other animals that may reduce the plant's fitness, and therefore put flowering plants in a challenging situation.