Combining Mass Spectrometry with Paternò-Büchi Reaction to Determine Double-Bond Positions in Lipids at the Single-Cell Level

Single cell MS (SCMS) techniques are under rapid development for molecular analysis of individual cells among heterogeneous populations. Lipids are basic cellular constituents playing essential functions in energy storage and the cellular signaling processes of cells. Unsaturated lipids are characterized with one or multiple carbon-carbon double (C═C) bonds, and they are critical for cell functions and human diseases. Characterizing unsaturated lipids in single cells allows for better understanding of metabolomic biomarkers and therapeutic targets of rare cells (e.g., cancer stem cells); however, these studies remain challenging. We developed a new technique using a micropipette needle, in which Paternò-Büchi (PB) reactions at C═C bond can be induced, to determine locations of C═C bonds in unsaturated lipids at the single-cell level. The micropipette needle is produced by combining a pulled glass capillary needle with a fused silica capillary. Cell lysis solvent and PB reagent (acetone or benzophenone) are delivered into the micropipette needle (tip size ≈ 15 um) through a fused silica capillary. The capillary needle plays multiple functions (i.e., single cell sampling probe, cell lysis container, microreactor, and nano-ESI emitter) in the experiments. Both regular (no reaction) and reactive (with PB reaction) SCMS analyses of the same cell can be achieved. C═C bond locations were determined from MS scan and MS/MS of PB products assisted by Python programs. This technique can potentially be used for other reactive SCMS studies to enhance molecular analysis for broad ranges of single cells.

Silver spray deposition for AgLDI imaging MS of cholesterol and other olefins on thin tissue sections

Olefins such as cholesterol and unsaturated fatty acids play important biological roles. Silver-assisted laser desorption ionization (AgLDI) takes advantage of the strong affinity of silver to conjugate with double bonds to selectively ionize these molecules for imaging mass spectrometry (IMS) experiments. For IMS studies, two main approaches for silver deposition have been described in the literature: fine coating by silver sputtering and spray deposition of silver nanoparticles. While these approaches allow for extremely high resolution IMS experiments to be conducted, they are not readily available to all laboratories. Herein, we present a silver nitrate spray deposition approach as an alternative to silver sputtering and nanoparticle deposition for routine IMS analysis. The silver nitrate spray has the same level of specificity and sensitivity for olefins, particularly cholesterol, and has shown to be capable of IMS experiments down to 10-μm spatial resolution. Minimal sample preparation and the affordability of silver nitrate make this a convenient and accessible technique worth considering.

Microbial inoculant and garbage enzyme reduced cadmium (Cd) uptake in Salvia miltiorrhiza (Bge.) under Cd stress

The uptake and accumulation of cadmium (Cd) in Salvia miltiorrhiza (Bge.) negatively affects the quality of its harvested roots, and seriously threatens human health. This study investigates the effect of a microbial inoculant (MI) and garbage enzyme (GE) on Cd uptake, the accumulation of bioactive compounds, and the community composition of microbes in the rhizosphere soil of S. miltiorrhiza under Cd stress. S. miltiorrhiza seedlings were transplanted to Cd-contaminated pots and irrigated with an MI, GE, a combination of an MI and GE (MIGE) or water (control). The results indicated that treatments with an MI, GE or MIGE can reduce Cd uptake in S. miltiorrhiza. The MIGE treatment had greater efficiency in reducing Cd uptake than the control (reduction by 37.90%), followed by the GE (25.31%) and MI (5.84%) treatments. Treatments with an MI, GE and MIGE had no significant impact on fresh and dry root biomass. Relative to the control, the MI treatment had the highest efficiency in increasing the accumulation of total tanshinones (an increase of 40.45%), followed by the GE treatment (40.08%), with the MIGE treatment (9.90%) treatment not having a more favorable effect than the separate application of an MI or GE. The salvianolic acid content for all groups was higher than the standard prescribed by Chinese pharmacopoeia, notwithstanding a slightly lower level in the treated groups relative to the control. In addition, metagenomic analysis indicated changes in the relative abundance of soil microbes associated with the bioremediation of heavy metals. The relative abundances of Brevundimonas, Microbacterium, Cupriavidus and Aspergillus were significantly greater in the treated groups than in the Control. These results suggest that using MI and GE, either separately or together, may not only improve the quality of S. miltiorrhiza but may also facilitate the microbial remediation of soil contaminated with Cd.

Polymethoxy-1-Alkenes Screening of Chlorella and Spirulina Food Supplements Coupled with In Vivo Toxicity Studies

Selected species of cyanobacteria and green algae have been reported to produce lipophilic polymethoxy-1-alkenes (PMAs) which were shown to exhibit in vivo teratogenicity. Considering that information on PMAs in Arthospira sp. (known commercially as Spirulina) and Chlorella sp. cultivated for food supplement production was essentially lacking, the present study screened Chlorella (n = 10) and Spirulina (n = 13) food supplements registered in the European Union. Mass spectrometry analysis of column fractionated extracts was performed. None of the four variants previously reported in some cyanobacteria and green algae, nor any potentially related structures were detected in the studied samples. Since the isolated lipophilic fractions contained various compounds, they were further screened for in vivo teratogenicity in Danio rerio embryo, and for the potential to induce oxidative stress and genotoxicity in the liver and neurotoxicity in the brain of adult zebrafish. None of the tested food supplements had detectable levels of PMAs or any potentially related structures. No teratogenicity was revealed except for spinal curvature induced by fractions obtained from two Chlorella products. Selected fractions revealed cytotoxicity as indicated by an increased level of reactive oxygen species, catalase activity, lipid peroxidation and increased frequency of DNA strand breaks in hepatic tissue. The majority (60%) of Chlorella fractions induced an increase in cholinesterase activity in zebrafish brain homogenate while exposure to 61.5% of Spirulina fractions was associated with its decrease. The present study confirms that Chlorella and Spirulina food supplements are free of teratogenic PMAs, although the observed in vivo toxicities raise questions regarding the quality of selected products.

Mass Spectrometric Detection and Characterization of Metabolites of Gemini Surfactants Used as Gene Delivery Vectors

Gemini surfactants are a class of lipid molecules that have been successfully used in vitro and in vivo as nonviral gene delivery vectors. However, the biological fate of gemini surfactants has not been well investigated. In particular, the metabolism of gemini surfactants after they enter cells as gene delivery vehicles is unknown. In this work, we used a high-resolution quadrupole-Orbitrap mass spectrometry (Q-Exactive) instrument to detect the metabolites of three model gemini surfactants, namely, (a) unsubstituted (16-3-16), (b) with pyridinium head groups (16(Py)-S-2-S-16(Py)), and (c) substituted with a glycyl-lysine di-peptide (16-7N(GK)-16). The metabolites were characterized, and structures were proposed, based on accurate masses and characteristic product ions. The metabolism of the three gemini surfactants was very different as 16-3-16 was not metabolized in PAM 212 cells, whereas 16(Py)-S-2-S-16(Py) was metabolized primarily via phase I reactions, including oxidation and dealkylation, producing metabolites that could be linked to its observed high toxicity. The third gemini surfactant 16-7N(GK)-16 was metabolized mainly via phase II reactions, including methylation, acetylation, glucose conjugation, palmityl conjugation, and stearyl conjugation. The metabolism of gemini surfactants provides insight for future directions in the design and development of more effective gemini surfactants with lower toxicity. The reported approach can also be applied to study the metabolism of other structurally related gemini surfactants.

Photolysis of 5-Azido-3-Phenylisoxazole at Cryogenic Temperature: Formation and Direct Detection of a Nitrosoalkene

To enhance the versatility of organic azides in organic synthesis, a better understanding of their photochemistry is required. Herein, the photoreactivity of azidoisoxazole 1 was characterized in cryogenic matrices with IR and UV-Vis absorption spectroscopy. The irradiation (λ = 254 nm) of azidoisoxazole 1 in an argon matrix at 13 K and in glassy 2-methyltetrahydrofuran (mTHF) at 77 K yielded nitrosoalkene 3. Density functional theory (DFT) and complete active space self-consistent field (CASSCF) calculations were used to aid the characterization of nitrosoalkene 3 and to support the proposed mechanism for its formation. It is likely that nitrosoalkene 3 is formed from the singlet excited state of azidoisoxazole 1 via a concerted mechanism or from cleavage of an intermediate singlet nitrene that does not undergo efficient intersystem crossing to its triplet configuration.

[Study on application of salvianolic acids reference extract in quality control of Salvia miltiorrhiza and salvianolic acids for injection]

The purpose of this study was to investigate the feasibility of the salvianolic acids reference extract for quality control for Salvia miltiorrhiza and salvianolic acids for injection. An Agilent ZORBAX SB-C18( 4. 6 mm×250 mm,5 μm) column was used with mobile phase consisting of 0. 1% formic acid-water and 0. 1% formic acid-acetonitrile in gradient elution procedure. The column temperature was 30 ℃; the flow rate was 1 m L·min-1; and the detection wavelength was 288 nm. The content of rosmarinic acid,lithospermic acid and salvianolic acid B in S. miltiorrhiza was determined by using the salvianolic acids reference extract as control substance. The content of caffeic acid,salvianolic acid E,rosmarinic acid,lithospermic acid,salvianolic acid B,and salvianolic acid Y in the salvianolic acids for injection was also determined. The linear relationship between chemicals was good( r>0. 998 9),and the injection precision RSD was 0. 30%-0. 90%. The sexual RSD is between 1. 4% and 3. 0%,and the RSD of the reproducibility of the extract is between 2. 1% and 5. 2%. The recovery rate of the three components in S. miltiorrhiza was 96. 80%-99. 20%,and the recovery rate of the six components in salvianolic acids for injection was 88. 90%-107. 5%. The solution of S. miltiorrhiza and salvianolic acids for injection were stable within 48 h. A total of 8 batches of S. miltiorrhiza and injection were determined by the reference extract,and the difference was smaller than that measured by the monomer control. This study preliminarily verified that the salvianolic acids reference extract can be used as a substitute for the monomer control for the quality control of S. miltiorrhiza and salvianolic acids for injection.

Investigation of emission characteristics of NMVOCs over urban site of western India

This is the first study to characterize the variation and emission of C₂-C₅ non-methane volatile organic compounds (NMVOCs) in a semi-urban site of western India based on measurements during February-December 2015. Anthropogenic NMVOCs show clear seasonal dependence with highest in winter and lowest in monsoon season. Biogenic NMVOCs likes isoprene show highest mixing ratios in the pre-monsoon season. The diurnal variation of NMVOC species can be described by elevated values from night till morning and lower values in the afternoon hours. The elevated levels of NMVOCs during night and early morning hours were caused mainly by weaker winds, temperature inversion and reduced chemical loss. The correlations between NMVOCs, CO and NOx indicate the dominant role of various local emission sources. Use and leakage of liquefied petroleum gas (LPG) contributed to the elevated levels of propane and butanes. Mixing ratios of ethylene, propylene, CO, NOx, etc. show predominant emissions from combustion of fuels in automobiles and industries. The Positive Matrix Factorization (PMF) source apportionments were performed for the seven major emission sectors (i.e. Vehicular exhaust, Mixed industrial emissions, Biomass/Fired brick kilns/Bio-fuel, Petrochem, LPG, Gas evaporation, Biogenic). Emissions from vehicle exhaust and industry-related sources contributed to about 19% and 40% of the NMVOCs, respectively. And the rest (41%) was attributed to the emissions from biogenic sources, LPG, gasoline evaporation and biomass burning. Diurnal and seasonal variations of NMVOCs were controlled by local emissions, meteorology, OH concentrations, long-range transport and planetary boundary layer height. This study provides a good reference for framing environmental policies to improve the air quality in western region of India.

Evaluation of antioxidant activities of various solvent extract from Sargassum serratifolium and its major antioxidant components

Sargassum serratifolium has been known to contain a high level of meroterpenoids as antioxidant components. We investigated antioxidant activities and active components in various solvent extracts from S. serratifolium. Ethyl acetate, ethanol, and methanol extracts showed relatively strong DPPH, ABTs, and superoxide radical scavenging activities. Hexane and ethyl acetate extract showed the strongest hydroxyl radical and reactive oxygen species (ROS), respectively, scavenging activities. Sargahydroquinoic acid (SHQA), sargachromanol (SCM) and sargaquinoic acid (SQA) were main antioxidant components in S. serratifolium. Ethanol extract showed the highest levels of SHQA, SCM, and SQA which comprised to be 227 ± 6.31 mg/g. SHQA and SCM exhibited stronger antioxidant capacities than SQA based on lower IC50 values in ROS, DPPH, ABTs, and superoxide radical scavenging assays. The result showed that ethanol is the most efficient extracting solvent for the active components from S. serratifolium and the plant has the potential as a natural antioxidant.

An appraisal of cuticular wax of Calotropis procera (Ait.) R. Br.: Extraction, chemical composition, biosafety and application

Plastic and polythene as hydrophobic materials become a grave concern due to their non-biodegradable nature, cumbersome recycling and waste management. Cuticular wax derived from Calotropis procera is explored as an eco-friendly and safe hydrophobic material. The effects of duration of exposure to solvent, solvent type, size and side of the leaf on cuticular wax yield have been studied. Leaf with the smallest area (10 cm²-25 cm²) was found to be the most suitable to isolate the wax. GC-MS analysis of the wax revealed that the wax consists of mainly esters, alkane and alkene. Mitochondrial reductase (MTT) and lactate dehydrogenase (LDH) assay have been carried out on M5S cell line at various concentrations and the results indicate that up to 1 μg/ml (acetone as solvent) and 3 μg/ml (chloroform as solvent) use of wax has no toxic effect. To evaluate the hydrophobic potential of the wax in developing hydrophobic paper water regains and contact angle has been measured. The gain in hydrophobicity of the paper is evident from the rise in contact angle (≥90˚) of paper coated with wax. Scanning electron micrograph and FTIR spectra generated physical and chemical evidence of coating of wax on paper.

Characterization of Key Odorants in Hoary Mountain Mint, Pycnanthemum incanum

Pycnanthemum incanum, a species of wild mountain mint endemic to North America, has a pungent mint-like odor that has not been fully characterized. Due in part to its high terpene content, P. incanum has broad potential for health-promoting, cosmetic, culinary, and food flavoring applications. Therefore, odorants of P. incanum were identified by coupling solvent assisted flavor evaporation (SAFE) and aroma extract dilution analysis (AEDA), which afforded 24 odorants including 14 odorants with flavor dilution (FD) factors ≥4. Selected odorants, including those with FD factors ≥16, were quantitated by stable isotope dilution assays (SIDAs), and odor activity values (OAVs) were determined. The odorants with the highest OAVs included β-ionone (floral, violet; OAV 300), myrcene (terpeny, OAV 120), linalool (floral, citrus; OAV 79), and pulegone (mint, medicinal; OAV 58). An odor-simulation model based on the quantitation closely matched the sensory attributes of the original P. incanum plant material. In addition, enantiomeric proportions of chiral odorants in P. incanum were determined by chiral chromatography.

Long TE PRESS and STEAM for measuring the triglyceride glycerol CH2 protons at 3 T

The glycerol methylene proton resonances (4-4.5 parts per million, ppm), which arise from the triglyceride backbone, are relevant to fat composition assessment and can be measured with proton MRS. The purpose of the presented work is to determine long TE (echo time) point resolved spectroscopy (PRESS) and stimulated echo acquisition mode (STEAM) values at 3 T to resolve the glycerol resonances from that of overlapping water. The response of the glycerol methylene protons of nine edible oils as a function of PRESS and STEAM TE (mixing time, TM = 20 ms) was investigated. In addition, high resolution NMR spectra of the oils were acquired at 16.5 T. Long TE values where J-coupling losses were lowest were selected, namely a TE of 180 ms for PRESS (first echo time 17 ms) and a TE of 100 ms for STEAM (mixing time 20 ms). Oil olefinic (≈5.4 ppm) to glycerol ratios were calculated from the long TE spectra and correlated with 16.5 T ratios. The two techniques yielded olefinic/glycerol ratios that correlated with 16.5 T ratios (R²  = 0.79 for PRESS and 0.90 for STEAM). The efficacy of the sequences in resolving the glycerol resonance from that of water was verified in vivo on tibial bone marrow of four healthy volunteers. In addition, the potential for using the glycerol methylene signal normalized to the methyl signal (≈0.9 ppm) to assess changes in free fatty acid content was demonstrated by measuring differences in spectra acquired from a triglyceride peanut oil phantom and from a phantom composed of a mixture of peanut oil and free fatty acid oleic acid.

Correlation between macroscopic characteristics and tissue-specific chemical profiling of the root of Salvia miltiorrhiza

BACKGROUND

Macroscopic identification has been widely used as a convenient method for herbal authentication and quality assessment. However, sensory evaluation heavily relied on personal experience and lacked enough evidence-based validations.

PURPOSE

We aim to reveal the correlation between macroscopic characteristics and tissue-specific chemical composition of the root of Salvia miltiorrhiza (SMR), and then develop a rapid method for quality assessment.

METHODS

Thirty-two batches of SMR were collected and evaluated. The outer-surface color and diameter as the representative tissue features of SMR were selected as the macroscopic indexes. SMR were then divided into three parts along transverse section as outer bark, middle part and central part, to explore the spatial distribution of chemicals. Outer-surface color information was converted into RGB values, while the diameter data were expressed by mean distance, respectively. Thirteen major components including eight salvianolic acids and five tanshinones in each part were determined by liquid chromatography tandem mass spectrometry. Finally, several mathematical models were established and optimized to evaluate the correlation between outer-surface color, size and chemical distribution.

RESULT

All five tanshinones mainly distributed in the outer bark while salvianolic acids were averagely existed among three parts. Correlational studies revealed that the surface color depth was significantly and positively correlated with tanshinone contents in the outer bark, while the size showed poor correlation in any chemicals. A color-oriented model was thus developed for the prediction of tanshinone contents in SMR, and a 9 × 9 standard color chart was created for easily use.

CONCLUSION

This study contributes an alternative method for macroscopic features-based quality evaluation of herbs, and also complements some scientific data for traditional knowledge.

Oviposition deterrent activity of basil plants and their essentials oils against Tuta absoluta (Lepidoptera: Gelechiidae)

The leafminer Tuta absoluta Meyrick (Lepidoptera: Gelechiidae) is one of the most important pests of tomato, reducing crop yields by up to 100% in greenhouses and fields, in several countries globally. Because synthetic insecticides lead to resistance and have adverse effects on natural enemies and the health of producers, alternative control methods are needed. In this study, we assessed the oviposition-deterring effect of basil plants, Ocimum gratissimum L. and O. basilicum L. (Lamiaceae), using dual-choice behavioural assays performed in flight tunnels. We found that both plants significantly reduced T. absoluta oviposition behaviour on a tomato plant located nearby. To evaluate the potential effect of basil volatile organic compounds, we formulated essential oils of both plant species in paraffin oil, and observed a similar oviposition-deterring effect. Gas chromatography analyses detected 18 constituents in these essential oils which the major constituents included thymol (33.3%), p-cymene (20.4%), γ-terpinene (16.9%), myrcene (3.9%) in O. gratissimum and estragol (73.8%), linalool (8.6%), β-elemene (2.9%) and E-β-ocimene (2.6%) in O. basilicum. Twenty and 33 compounds were identified of the volatiles collected on O. gratissimum and O. basilicum plants, respectively. The main components include the following: p-cymene (33.5%), γ-terpinene (23.6%), α-terpinene (7.2%), α-thujene (6.7%) and E-α-bergamotene (38.9%) in O. gratissimum, and methyl eugenol (26.1%), E-β-ocimene (17.7%), and linalool (9.4%) in O. basilicum. Four compounds (α-pinene, β-pinene, Myrcene, Limonene) were common in essential oils and plants. Our results suggest the valuable potential of basil and associated essential oils as a component of integrated management strategies against the tomato leafminer.

Characterization of volatile organic compounds and the impacts on the regional ozone at an international airport

In this study, the measurement of volatile organic compounds (VOCs) was conducted at Beijing Capital International Airport (ZBAA) and a background reference site in four seasons of 2015. Total concentrations of VOCs were 72.6 ± 9.7, 65.5 ± 8.7, 95.8 ± 11.0, and 79.2 ± 10.8 μg/m³ in winter, spring, summer, and autumn, respectively. The most abundant specie was toluene (10.1%-17.4%), followed by benzene, ethane, isopentane, ethane, acetylene, and n-butane. Seasonal variations of VOCs were analyzed, and it was found that the highest concentration occurring in summer, while the lowest in spring. For the diurnal variation, the concentration of VOCs in the daytime (9:00-15:00) was less than that at night (15:00-21:00) obviously. Ozone Formation Potential (OFP) was calculated by using Maximum Incremental Reactivity (MIR) method. The greatest contribution to OFP from alkenes and aromatics, which accounted for 27.3%-51.2% and 36.6%-58.6% of the total OFP. The WRF-CMAQ model was used to simulate the impact of airport emissions on the surrounding area. The results indicated that the maximum impact of VOCs emissions and all sources emissions at the airport on O₃ was 0.035 and -23.8 μg/m³, respectively. Meanwhile, within 1 km from the airport, the concentration of O₃ around the airport was greatly affected by airport emitted.

Electron ionization mass spectrometry fragmentation and multiple reaction monitoring quantification of bacterial metabolites of the sea ice biomarker proxy IP25 in Arctic sediments

RATIONALE

3,9,13-Trimethyl-6-(1,5-dimethylhexyl)tetradecan-1,2-diol and 2,8,12-trimethyl-5-(1,5-dimethylhexyl)tridecanoic acid appear to be produced during the bacterial metabolism of IP₂₅ , a highly branched isoprenoid lipid often employed for past Arctic sea ice reconstruction. Characterization and quantification of these metabolites in sediments are essential to determine if bacterial degradation may exert a significant influence on IP₂₅ -based palaeo sea ice reconstructions.

METHODS

Electron ionization mass spectrometry (EIMS) fragmentation pathways of 3,9,13-trimethyl-6-(1,5-dimethylhexyl)tetradecan-1,2-diol and 2,8,12-trimethyl-5-(1,5-dimethylhexyl)tridecanoic acid trimethylsilyl (TMS) derivatives were investigated. These pathways were deduced by: (i) low-energy collision-induced dissociation (CID) gas chromatography/tandem mass spectrometry (GC/MS/MS), (ii) accurate mass measurement, and (iii) deuterium labelling.

RESULTS

CID-MS/MS analyses, accurate mass measurement and deuterium-labelling experiments enabled us to elucidate the EIMS fragmentations of 3,9,13-trimethyl-6-(1,5-dimethylhexyl)tetradecan-1,2-diol and 2,8,12-trimethyl-5-(1,5-dimethylhexyl)tridecanoic acid TMS derivatives. Some specific fragment ions useful in addition to chromatographic retention times for further characterization could be identified. As an application of some of the described fragmentations, the TMS derivatives of these metabolites were characterized and quantified in MRM mode in different Arctic sediments.

CONCLUSIONS

EIMS fragmentations of 3,9,13-trimethyl-6-(1,5-dimethylhexyl)tetradecan-1,2-diol and 2,8,12-trimethyl-5-(1,5-dimethylhexyl)tridecanoic acid TMS derivatives exhibit specific fragment ions, which appear to be very useful for the quantification of these bacterial metabolites of the palaeo tracer IP₂₅ in sediments.

A quality marker study on salvianolic acids for injection

BACKGROUND

The quality of Chinese medicine (CM) has being an active and challenging research area for CM. Prof. Chang-Xiao Liu et al first proposed the concept of quality marker (Q-Marker) for the quality evaluation and control on CM. This article describe the exploratory studies of Q-Marker in salvianolic acids for injection (SAI) based on this new concept.

PURPOSE

This study was designed to screen Q-Marker of SAI and establish its quality control method based on the concept of CM Q-Marker.

METHODS

Based on the concept of CM Q-Marker, the SAI was investigated for the identification of chemical components and their sources. The pharmacological effects on cerebral ischemia and reperfusion induced injury in rats were also investigated. Furthermore, the target cell extracts and pharmacokinetic studies were conducted to screen Q-Markers. Finally, the fingerprints and determination based on Q-Markers were established to assess the quality of SAI more effectively.

RESULTS

Overall, 20 constituents in SAI were identified. It was found that salvianolic acid B (SA-B), rosmarinic acid (RA), lithospermic acid (LA), salvianolic acid D (SA-D) and salvianolic acid Y (SA-Y) are major chemical components of SAI. Based on chemical components identifications, analysis of their sources, target cell extracts and pharmacokinetic studies, four phenolic acids, namely SA-B, RA, LA and SA-D, were screened and determined as effective Q-Markers of SAI.

CONCLUSION

This study demonstrated that the described method is a powerful approach for detecting Q-Markers, which can be used as control index for the quality assessment of CM.

Are Isomeric Alkenes Used in Species Recognition among Neo-Tropical Stingless Bees (Melipona Spp)

Our understanding of the role of cuticular hydrocarbons (CHC) in recognition is based largely on temperate ant species and honey bees. The stingless bees remain relatively poorly studied, despite being the largest group of eusocial bees, comprising more than 400 species in some 60 genera. The Meliponini and Apini diverged between 80-130 Myr B.P. so the evolutionary trajectories that shaped the chemical communication systems in ants, honeybees and stingless bees may be very different. The aim of this study was to study if a unique species CHC signal existed in Neotropical stingless bees, as has been shown for many temperate species, and what compounds are involved. This was achieved by collecting CHC data from 24 colonies belonging to six species of Melipona from North-Eastern Brazil and comparing the results with previously published CHC studies on Melipona. We found that each of the eleven Melipona species studied so far each produced a unique species CHC signal based around their alkene isomer production. A remarkable number of alkene isomers, up to 25 in M. asilvai, indicated the diversification of alkene positional isomers among the stingless bees. The only other group to have really diversified in alkene isomer production are the primitively eusocial Bumblebees (Bombus spp), which are the sister group of the stingless bees. Furthermore, among the eleven Neotropical Melipona species we could detect no effect of the environment on the proportion of alkane production as has been suggested for some other species.

Simultaneous determination of eight bioactive components of Qishen Yiqi dripping pills in rat plasma using UFLC-MS/MS and its application to a pharmacokinetic study

In this study, a rapid and reliable ultra-fast liquid chromatography-tandem mass spectrometry method was developed and validated for the simultaneous determination of eight active ingredients, including astragaloside IV, ononin, tanshinol, protocatechualdehyde, protocatechuic acid, salvianolic acid D, rosmarinic acid and ginsenoside Rg1 , in rat plasma. The plasma samples were pretreated by protein precipitation with acetonitrile. Chromatographic separation was performed on a Waters Acquity UPLC® BEH C18 column (1.7 μm particles, 2.1 × 100 mm). The mobile phase consisted of 0.1% aqueous formic acid (A)-acetonitrile with 0.1% formic acid (B) at a flow rate of 0.4 mL/min. Quantification was performed on a triple quadruple tandem mass spectrometry with electrospray ionization by multiple reaction monitoring both in the negative and in the positive ion mode. The lower limit of quantification of tanshinol was 2.0 ng/mL and the others were 5.0 ng/mL. The extraction recoveries, matrix effects, intra- and inter-day precision and accuracy of eight tested components were all within acceptable limits. The validated method was successfully applied to the pharmacokinetic study of the eight active constituents after intragastric administration of three doses (1.0, 3.0, 6.0 g/kg body weight) of Qishen Yiqi Dripping Pills to rats.

Footprint, weathering, and persistence of synthetic-base drilling mud olefins in deep-sea sediments following the Deepwater Horizon disaster

Olefin-based synthetic-based drilling mud (SBM) was released into the Gulf of Mexico as a result of the Deepwater Horizon (DWH) disaster in 2010. We studied the composition of neat SBM and, using conventional GC-FID, the extent, concentration, and chemical character of SBM-derived olefins in >3600 seafloor sediments collected in 2010/2011 and 2014. SBM-derived (C₁₄-C₂₀) olefins occurred (up to 10cm deep) within a 6.5km² "footprint" around the well. The olefin concentration in most sediments decreased an order of magnitude between 2010/2011 and 2014, at least in part due to biodegradation, evidenced by the preferential loss C₁₆ and C₁₈ linear (α- and internal) versus branched olefins. Based on their persistence for 4-years in sediments around the Macondo well, and 13-years near a former unrelated drill site (~62km away), weathered SBM-derived olefins released during the DWH disaster are anticipated to persist in deep-sea sediment for (at least) a comparable duration.

Source Apportionment of Volatile Organic Compounds in an Urban Environment at the Yangtze River Delta, China

Volatile organic compounds (VOCs) were collected continuously during June-August 2013 and December 2013-February 2014 at an urban site in Nanjing in the Yangtze River Delta. The positive matrix factorization receptor model was used to analyse the sources of VOCs in different seasons. Eight and seven sources were identified in summer and winter, respectively. In summer and winter, the dominant sources of VOCs were vehicular emissions, liquefied petroleum gas/natural gas (LPG/NG) usage, solvent usage, biomass/biofuel burning, and industrial production. In summer, vehicular emissions made the most significant contribution to ambient VOCs (38%), followed by LPG/NG usage (20%), solvent usage (19%), biomass/biofuel burning (13%), and industrial production (10%). In winter, LPG/NG usage accounted for 36% of ambient VOCs, whereas vehicular emissions, biomass/biofuel burning, industrial production and solvent usage contributed 30, 18, 9, and 6%, respectively. The contribution of LPG/NG usage in winter was approximately four times that in summer, whereas the contribution from biomass/biofuel burning in winter was more than twice that in summer. The sources related to vehicular emissions and LPG/NG usages were important. Using conditional probability function analysis, the VOC sources were mainly associated with easterly, northeasterly and southeasterly directions, pointing towards the major expressway and industrial area. Using the propylene-equivalent method, paint and varnish (23%) was the highest source of VOCs in summer and biomass/biofuel burning (36%) in winter. Using the ozone formation potential method, the most important source was biomass/biofuel burning (32% in summer and 47% in winter). The result suggests that the biomass/biofuel burning and paint and varnish play important roles in controlling ozone chemical formation in Nanjing.

Influence of Winemaking Processing Steps on the Amounts of (E)-2-Decenal and Tridecane as Off-Odorants Caused by Brown Marmorated Stink Bug (Halyomorpha halys)

Brown marmorated stink bugs (BMSB) release stress compounds, tridecane and (E)-2-decenal, that affect final wine quality. This study focuses on determining the effect of wine processing on (E)-2-decenal and tridecane release in both red and white wines. Wines were produced by adding live BMSB to grape clusters at densities of 0, 0.3, 1, and 3 bugs/cluster. Compound concentrations were measured using headspace solid phase microextraction with multidimensional gas chromatography and mass spectrometry. For red wines, the highest levels of stress compounds were found using 3 BMSB/cluster [tridecane, 614 μg/L; (E)-2-decenal, 2.0 μg/L]. Pressing was found to be the critical process point for stress compound release, and additional pressing processes, press types, and press fractions were investigated. BMSB taint for white wines was not found to be problematic with respect to wine quality. An action control of 3 BMSB/cluster is recommended as this was related to the known consumption rejection threshold for (E)-2-decenal.

Valdecoxib Recovers the Lipid Composition, Order and Dynamics in Colon Cancer Cell Lines Independent of COX-2 Expression: An ATR-FTIR Spectroscopy Study

Prostanoids play an important role in a variety of physiological and pathophysiological processes including inflammation and cancer. The rate-limiting step in the prostanoid biosynthesis pathway is catalyzed by cyclooxygenases (COXs). Aberrant expression of the inducible isoform COX-2 plays a significant role in colon cancer initiation and progression. In this study, we have hypothesized that COX-2 specific inhibitors such as Valdecoxib (VLX), being highly hydrophobic, may alter biophysical properties of cellular lipids. In this study, COX-2 expressing (HT29) and COX-2 non-expressing (SW620) colon cancer cell lines were treated with VLX and examined using attenuated total reflection infrared spectroscopy. The results revealed that VLX treatment decreased lipid fluidity in the cells irrespective of COX-2 expression status and affected order parameters of the lipids in both cell lines. Cluster analysis also indicated that the spectral differences between the two cell lines are profound and could be successfully differentiated. Valdecoxib treatment could enhance the composition, order and dynamics of the lipids of colon cancer cells independently of its COX-2 inhibitory mechanism. Valdecoxib has therapeutic effects upon colon cancer, therefore it can be used as an adjuvant and/or chemopreventive agent for colon cancer.

Characterization and source apportionment of volatile organic compounds based on 1-year of observational data in Tianjin, China

From November 2014 to October 2015, the concentrations of volatile organic compounds (VOCs), O₃ and NOx were simultaneously monitored by using online instruments at the air monitoring station belonged to Tianjin Environmental Protection Bureau (TEPB). The results indicated that VOCs concentrations were higher in autumn and lower in spring, while O₃ concentrations were higher in summer, and lower in winter. The diurnal variations of VOCs and NOx (NO₂ plus NO) showed opposite tendency comparing to that of O₃. The concentrations of alkanes were higher (the average of 18.2 ppbv) than that of aromatics (5.3 ppbv) and alkenes (5.2 ppbv), however, the alkenes and aromatics made larger contributions to ozone because of their high reactivity. Tianjin belonged to the VOC-limited region during most of seasons (except summer) according to the VOC/NOx ratios (the 8:1 threshold). The automobile exhaust, industrial emission, liquefied petroleum gas/natural gas (LPG/NG), combustion, gasoline evaporation, internal combustion engine emission and solvent usage were identified as major sources of VOCs by Positive Matrix Factorization (PMF) model in Tianjin, and the contributions to VOCs for the entire year were 23.1%, 19.9%, 18.6%, 10.6%, 8.7%, 5.4% and 4.7%, respectively. The conditional probability function (CPF) analysis indicated that the contributing directions of automobile exhaust and industrial emission were mainly affected by source distributions, and that of other sources might be mainly affected by wind direction. The backward trajectory analysis indicated that the trajectory of air mass originated from Mongolia, which reflected the features of large-scale and long-distance air transport, and that of beginning in Jiangsu, Shandong and Tianjin, which showed the features of small-scale and short-distance. Tianjin, Beijing, Hebei and Northwest of Shandong were identified as major potential source-areas of VOCs by using potential source contribution function (PSCF) and concentration-weighted trajectory (CWT) models.

Chemical Composition, Anticonvulsant Activity, and Toxicity of Essential Oil and Methanolic Extract of Elettaria cardamomum

Elettaria cardamomum is an aromatic spice (cardamom) native to the humid Asian areas, which contains some compounds with a potential anticonvulsant activity. Various pharmacological properties such as anti-inflammatory, analgesic, antioxidant, and antimicrobial effects have been related to this plant. This research was conducted to examine the probable protective impact of the essential oil and methanolic extract of E. cardamomum against chemically (pentylentetrazole)- and electrically (maximal electroshock)-induced seizures in mice. In addition, neurotoxicity, acute lethality, and phytochemistry of the essential oil and methanolic extract were estimated. The TLC method showed the presence of kaempferol, rutin, and quercetin in the extract, and the concentration of quercetin in the extract was 0.5 µg/mL. The major compounds in the essential oil were 1,8-cineole (45.6 %), α-terpinyl acetate (33.7 %), sabinene (3.8 %), 4-terpinen-4-ol (2.4 %), and myrcene (2.2 %), respectively. The extract and essential oil showed significant neurotoxicity in the rotarod test at the doses of 1.5 g/kg and 0.75 mL/kg, respectively. No mortalities were observed up to the doses of 2 g/kg and 0.75 mL/kg for the extract and essential oil. The essential oil was effective in both the pentylentetrazole and maximal electroshock models; however, the extract was only effective in the pentylentetrazole model. The study suggested that E. cardamomum methanolic extract had no significant lethality in mice. Both the essential oil and methanolic extract showed movement toxicity. Anticonvulsant effects of E. cardamomum were negligible against the seizures induced by pentylentetrazole and maximal electroshock.