Changes in chiral monoterpenes during drought in a rainforest reveal distinct source mechanisms

2020 ◽  
Author(s):  
Joseph Byron ◽  
Christiane Werner ◽  
Nemiah Ladd ◽  
Laura Meredith ◽  
Gemma Purser ◽  
...  
Keyword(s):  
Atmospheric Chemistry ◽  
Biologically Active ◽  
Environmental Drivers ◽  
Daily Maximum ◽  
Optical Isomers ◽  
Alpha Pinene ◽  
Average Maximum ◽  
Source Mechanisms ◽  
Distinct Source ◽  
The Individual

<p>Monoterpenes are used by plants as antioxidants in the defense against reactive oxygen species and are also contributors to the formation of secondary organic aerosol and cloud condensation nuclei. Understanding how the emissions of monoterpenes from biogenic sources change due to different stresses such as drought is of importance as more frequent drought events are expected to occur in the future due to climate change. Monoterpenes such as alpha pinene and limonene exist as optical isomers in mirror image forms, (+) and (-). Studies on the effect of different stresses on plant emissions commonly measure the sum of enantiomers rather than conducting separate measurements for the individual enantiomers [1]. Recent measurements of chiral monoterpenes have highlighted the importance of independently measuring the individual enantiomers of a chiral pair, due to differences such as environmental drivers [2] and local measurement source [3]. Despite the enantiomers of the same monoterpene having the same chemical properties, they can interact differently with biologically active chiral molecules such as those that exist as olfactory receptors within insect antennae [4].</p><p>The atmospheric dynamics of chiral monoterpenes from beneath the canopy of the tropical rainforest biome at Biosphere 2, Arizona, USA, were measured during pre-drought, drought and rewetting using an online GC-MS during the B2 Water, Atmosphere and Life Dynamics campaign (B2WALD). Furthermore, sorbent tube samples were obtained from different forest compartments, to investigate the compartment specific chiral VOC emission. Drought was found to be a driver of a change in the enantiomeric excess of specific monoterpenes. (-) alpha pinene was the dominant monoterpene present in agreement with results from the Amazonian rainforest despite there being no atmospheric chemistry in the Biosphere greenhouse. Interestingly, during the pre-drought phase, due to the conditions in the greenhouse, (-) alpha pinene showed an average daily maximum at 11:00 while (+) alpha pinene peaked at 15:00, coincident with peak light and temperature respectively. By the rewet phase, the average daily maximum for (-) alpha pinene shifted to 13:00, coincident with peak Isoprene, whilst it remained at 15:00 for (+) alpha pinene. The average maximum daily mixing ratios of (+) and (-) alpha pinene, during the drought phase, increased by a factor of 4 and 2 respectively, when compared to the pre-drought values. These results reveal distinct source mechanisms for individual enantiomers and the differing impact drought has on the individual enantiomers in a rainforest ecosystem.</p><p> </p><p> </p><ol><li>Lavoir, A.V., et al., Drought reduced monoterpene emissions from the evergreen Mediterranean oak <em>Quercus ilex</em>: results from a throughfall displacement experiment. Biogeosciences, 2009. <strong>6</strong>(7): p. 1167-1180.</li> <li>Song, W., et al., Laboratory and field measurements of enantiomeric monoterpene emissions as a function of chemotype, light and temperature. Biogeosciences, 2014. <strong>11</strong>(5): p. 1435-1447.</li> <li>Staudt, M., et al., Compartment specific chiral pinene emissions identified in a Maritime pine forest. Science of The Total Environment, 2019. <strong>654</strong>: p. 1158-1166.</li> <li>Wibe, A., et al., Enantiomeric Composition of Monoterpene Hydrocarbons in Some Conifers and Receptor Neuron Discrimination of α-Pinene and Limonene Enantiomers in the Pine Weevil, Hylobius abietis. Journal of Chemical Ecology, 1998. <strong>24</strong>(2): p. 273-287.</li> </ol><p> </p>

Bioavailability of naringenin chalcone in humans after ingestion of cherry tomatoes

2020 ◽  
Vol 90 (5-6) ◽  
pp. 411-416 ◽  
Author(s):  
Carina Kolot ◽  
Ana Rodriguez-Mateos ◽  
Rodrigo Feliciano ◽  
Katharina Bottermann ◽  
Wilhelm Stahl
Keyword(s):  
Plasma Levels ◽  
Average Concentration ◽  
Biologically Active ◽  
Thiol Groups ◽  
Structural Element ◽  
Active Molecule ◽  
Reactive Center ◽  
Average Maximum ◽  
Alpha Beta ◽  
Cherry Tomatoes

Abstract. Chalcones are a type of flavonoids characterized by an α-β unsaturated structural element which may react with thiol groups to activate pathways such as the Nrf2-Keap-1 system. Naringenin chalcone is abundant in the diet but little is known about its bioavailability. In this work, the bioavailability of naringenin chalcone from tomatoes was investigated in a group of healthy men (n=10). After ingestion of 600 grams of tomatoes providing a single dose of 17.3 mg naringenin chalcone, 0.2 mg of naringenin, and 195 mg naringin plasma levels of free and conjugated naringenin and naringenin chalcone (glucuronide and sulfate) were analyzed by UHPLC-QTOF-MS at 0.5, 1, 3, and 6 h post-consumption. Plasma levels of conjugated naringenin increased to about 12 nmol/L with a maximum at about 3 h. Concentrations of free naringenin hardly elevated above baseline. Plasma levels of free and conjugated naringenin chalcone significantly increased. A maximum of the conjugated chalcone was reached at about 3 h after ingestion with an average concentration of about 0.5 nmol/L. No free chalcone was detectable at baseline but low amounts of the unconjugated compound could be detected with an average maximum of 0.8 nmol/L at about 1 h after ingestion. The data demonstrate that naringenin chalcone is bioavailable in humans from cherry tomatoes as a dietary source. However, availability is poor and intramolecular cyclisation as well as extended metabolism likely contribute to the inactivation of the reactive alpha-beta unsaturated reactive center as well as the excretion of the biologically active molecule, respectively.

Separation and Characterization of Standard Propoxyphene Diastereomers and Their Determination in Pharmaceutical and Illicit Preparations

1981 ◽  
Vol 64 (4) ◽  
pp. 875-883
Author(s):  
Shiv K Soni ◽  
Daniel Van Gelder
Keyword(s):  
High Pressure ◽  
Optical Isomers ◽  
Gold Chloride ◽  
Melting Points ◽  
Eutectic Melting ◽  
Racemic Mixtures ◽  
The Individual ◽  
Isomeric Mixtures ◽  
Asymmetric Carbon

Abstract Due to the existence of 2 asymmetric carbon atoms in: the propoxyphene molecule, there are 4 diastereomers: alpha dextro, alpha levo, beta dextro, and beta levo. Only α-d-propoxyphene is included under the federal Controlled Substances Act. Baseline separations of propoxyphene from various incipients (aspirin, caffeine, phenacetin, and acetaminophen) present in pharmaceutical and illicit preparations, and between the alpha and beta diastereomers, were achieved by high pressure liquid chromatography. The column eluant was collected and propoxyphene was extracted. The optical isomers were differentiated and characterized by melting points and by chemical microcrystalline tests. Using hot stage thermomicroscopy, the eutectic melting points of binary isomeric mixtures of propoxyphene bases and salts were found to be depressed about 10° and 15-30°C, respectively, below the individual isomer melting points. The characteristic microcrystals formed with the alpha racemic mixtures by using a glycerin-aqueous gold chloride reagent were not produced by the beta racemic mixtures.

Investigation of atmospheric hydrogen cyanide: a modelling perspective

2021 ◽  
Author(s):  
Antonio G. Bruno ◽  
Jeremy J. Harrison ◽  
David P. Moore ◽  
Martyn P. Chipperfield ◽  
Richard J. Pope
Keyword(s):  
Biomass Burning ◽  
Atmospheric Chemistry ◽  
Hydrogen Cyanide ◽  
Three Dimensional ◽  
Oxidation Reactions ◽  
Loss Mechanism ◽  
Mixing Ratios ◽  
The Individual ◽  
Atmospheric Loss ◽  
Physical And Chemical

<p>Hydrogen cyanide (HCN) is one of the most abundant cyanides present in the global atmosphere, and is a tracer of biomass burning, especially for peatland fires. The HCN lifetime is 2–5 months in the troposphere but several years in the stratosphere. Understanding the physical and chemical mechanisms of HCN variability is important due to its non-negligible role in the nitrogen cycle. The main source of tropospheric HCN is biomass burning with minor contributions from industry and transport. The main loss mechanism of atmospheric HCN is the reaction with the hydroxyl radical (OH). Ocean uptake is also important, while in the stratosphere oxidation by reaction with O(<sup>1</sup>D) needs to be considered.</p><p>HCN variability can be investigated using chemical model simulations, such as three-dimensional (3-D) chemical transport models (CTMs). Here we use an adapted version of the TOMCAT 3-D CTM at a 1.2°x1.2° spatial resolution from the surface to ~60 km for 12 idealised HCN tracers which quantify the main loss mechanisms of HCN, including ocean uptake, atmospheric oxidation reactions and their combinations. The TOMCAT output of the HCN distribution in the period 2004-2020 has been compared with HCN profiles measured by the Atmospheric Chemistry Experiment Fourier Transform Spectrometer (ACE-FTS) over an altitude grid from 6 to 42 km. HCN model data have also been compared with ground-based measurements of HCN columns from NDACC FTIR stations and with in-situ volume mixing ratios (VMRs) from NOAA ground-based measurement sites.</p><p>The model outputs for the HCN tracer with full treatment of the loss processes generally agree well with ACE-FTS measurements, as long as we use recent laboratory values for the atmospheric loss reactions. Diagnosis of the individual loss terms shows that decay of the HCN profile in the upper stratosphere is due mainly to the O(<sup>1</sup>D) sink. In order to test the magnitude of the tropospheric OH sink and the magnitude of the ocean sink, we also show the comparisons of the model tracers with surface-based observations. The implications of our results for understanding HCN and its variability are then discussed.</p>

Newly developed instrumentation for measuring highly oxidized molecules at atmospheric pressure

2021 ◽  
Author(s):  
Paap Koemets ◽  
Sander Mirme ◽  
Kuno Kooser ◽  
Heikki Junninen
Keyword(s):  
Gas Phase ◽  
Atmospheric Chemistry ◽  
Atmospheric Pressure ◽  
Chemical Ionization ◽  
Measurement Technology ◽  
Differential Mobility Analyzer ◽  
Neutral Cluster ◽  
Differential Mobility ◽  
Alpha Pinene ◽  
Ambient Measurements

<p>The Highly Oxidized Molecule Ion Spectrometer (HOMIS) is a novel instrument for measuring the total concentration of highly oxidized molecules (HOM-s) (Bianchi et al., 2019) at atmospheric pressure. The device combines a chemical ionization charger with a multi-channel differential mobility analyzer. The chemical ionization charger is based on the principles outlined by Eisele and Tanner (1993). The charger is attached to a parallel differential mobility analyzer identical to the ones used in the Neutral cluster and Air Ion Spectrometer (NAIS, Mirme 2011), but with modified sample and sheath air flow rates to improve the mobility resolution of the device. The complete mobility distribution in the range from 3.2 to 0.056 cm<sup>2</sup>/V/s is measured simultaneously by 25 electrometers. The range captures the charger ions, monomers, dimers, trimers but also extends far towards larger particles to possibly detect larger HOM-s that have not been measured with existing instrumentation. The maximum time resolution of the device is 1 second allowing it to detect rapid changes in the sample. The device has been designed to be easy to use, require little maintenance and work reliably in various environments during long term measurements.</p><p>First results of the prototype were acquired from laboratory experiments and ambient measurements. Experiments were conducted at the Laboratory of Environmental Physics, University of Tartu. The sample was drawn from a reaction chamber where alpha-pinene and ozone were introduced. Initial results show a good response when concentrations of alpha-pinene and ozone were changed. </p><p>Ambient measurements were conducted at the SMEAR Estonia measurement station in a hemiboreal forest for 10 days in the spring and two months in the winter of 2020. The HOMIS measurements were performed together with a CI-APi-TOF (Jokinen et al., 2012).</p><p> </p><p>References:</p><p>Bianchi, F., Kurtén, T., Riva, M., Mohr, C., Rissanen, M. P., Roldin, P., Berndt, T., Crounse, J. D., Wennberg, P. O., Mentel, T. F., Wildt, J., Junninen, H., Jokinen, T., Kulmala, M., Worsnop, D. R., Thornton, J. A., Donahue, N., Kjaergaard, H. G. and Ehn, M. (2019), “Highly Oxygenated Organic Molecules (HOM) from Gas-Phase Autoxidation Involving Peroxy Radicals: A Key Contributor to Atmospheric Aerosol”, Chemical Reviews, 119, 6, 3472–3509</p><p>Eisele, F. L., Tanner D. J. (1993), “Measurement of the gas phase concentration of H2SO4 and methane sulfonic acid and estimates of H2SO4 production and loss in the atmosphere”, JGR: Atmospheres, 98, 9001-9010</p><p>Jokinen T., Sipilä M., Junninen H., Ehn M., Lönn G., Hakala J., Petäjä T., Mauldin III R. L., Kulmala M., and Worsnop D. R. (2012), “Atmospheric sulphuric acid and neutral cluster measurements using CI-APi-TOF”, Atmospheric Chemistry and Physics, 12, 4117–4125</p><p>Mirme, S. (2011), “Development of nanometer aerosol measurement technology”, Doctoral thesis, University of Tartu</p>

scholarly journals HYBRID FORMATION BETWEEN BACTERIAL ENDOTOXINS

1967 ◽  
Vol 126 (1) ◽  
pp. 63-79 ◽  
Author(s):  
Jon A. Rudbach ◽  
Kelsey C. Milner ◽  
Edgar Ribi
Keyword(s):  
Bile Salt ◽  
Sodium Deoxycholate ◽  
Enteric Bacteria ◽  
Biologically Active ◽  
Antigenic Determinants ◽  
Hybrid Formation ◽  
Bacterial Endotoxins ◽  
New Type ◽  
The Individual

When endotoxins extracted from enteric bacteria were mixed in the presence of sodium deoxycholate, and the bile salt was subsequently removed by dialysis or by extraction with ethanol, a new type of endotoxin was formed. The latter material was as biologically active as the original endotoxins and possessed a combination of antigenic determinants that were previously unique to each of the individual endotoxins in the mixture. This hybrid formation between endotoxins was detected by immunodiffusion and radioautography and by quantitative precipitation procedures.

Time-Course Studies of Phytoalexins and Glucosinolates in UV-Irradiated Turnip Tissue

1991 ◽  
Vol 46 (3-4) ◽  
pp. 189-193 ◽  
Author(s):  
Kenji Monde ◽  
Mitsuo Takasugi ◽  
Jenny A. Lewis ◽  
G. Roger Fenwick
Keyword(s):  
High Performance ◽  
Time Course ◽  
Brassica Campestris ◽  
Structural Features ◽  
Biologically Active ◽  
Indole Glucosinolates ◽  
Freeze Dried ◽  
Indole Phytoalexins ◽  
The Individual ◽  
Complex Manner

Sliced turnip root (Brassica campestris L. ssp rapa) was irradiated for a total of 20 min with a 15 W germicidal lamp and the tissue incubated at 25 °C. The effects of such treatment on indole phytoalexins (methoxybrassinin (I); brassinin (II); cyclobrassinin (III); spirobrassinin (IV) and glucosinolates were determined using high performance liquid chromatography procedures. Accumulation of phytoalexins I - III was evident within 8 h of irradiation, whilst formation of spirobrassinin was evident only after 24 h. Maximal levels of III and IV (> 100 μg g-1 freeze dried tissue) were greater than those of I and II (27 and 17 μg g-1, respectively). The individual glucosinolate levels were affected in a complex manner; whilst most glucoinolates decreased on storage, the levels of indole glucosinolates, glucobrassicin (XI) and 1-methoxyglucobrassicin (XIII), increased until 5 to 6 days after irradiation and thereafter declined. Whilst structural features of I - IV , XI and XIII suggest close biosynthetic relationships between these classes of biologically-active indoles, further studies are needed to establish this point unambiguously.

Analysis of Changes in the Natural and Climatic Conditions of the Functioning of the Construction Industry (Operation of Buildings and Structures) in the Region

2018 ◽  
Vol 931 ◽  
pp. 1031-1036
Author(s):  
Boris A. Ashabokov ◽  
Alexander V. Shapovalov ◽  
Alla A. Tashilova
Keyword(s):  
Construction Industry ◽  
Extreme Values ◽  
Climatic Conditions ◽  
Daily Maximum ◽  
Climatic Zones ◽  
Air Temperatures ◽  
Average Maximum ◽  
European Part Of Russia ◽  
Different Seasons ◽  
Southern Russia

The manifestations of climatic changes on the territory of the south of the European part of Russia are considered. The estimates for the changes in the seasonal and annual average, maximum and minimum air temperatures, in the seasonal and annual sum of precipitation, daily maximum precipitation as well as the dynamics of the number of their extreme values ​​in different climatic zones of southern Russia and in different seasons are obtained. Possible effects of climate change on the functioning of the construction industry in different climatic zones of the region are considered.

Quantitative cytochemistry: the basis of sensitive bioassays, for comparison of bio-and immuno-reactive hormone values.

1978 ◽  
Vol 24 (8) ◽  
pp. 1399-1407 ◽  
Author(s):  
L Bitensky ◽  
J Chayen
Keyword(s):  
Physiological Effect ◽  
Biologically Active ◽  
Antigenic Determinants ◽  
Target Cells ◽  
Biochemical Activity ◽  
Cytochemical Bioassay ◽  
Polypeptide Hormones ◽  
Increased Sensitivity ◽  
The Individual ◽  
Quantitative Cytochemistry

Abstract Cytochemistry now extends biochemistry down to the single-cell level. Special procedures have been developed for cutting sections of uniform thickness with no measurable or detectable artifact. The cytochemical bioassays use chromogenic reactions with the immediate precipitation of the resulting chromophore so that biochemical activity can be related to the individual cells constituting a tissue. This activity, in individual cells, is measured by scanning and integrating microdensitometry which also increases the sensitivity of cytochemical measurement over that of conventional biochemistry. A hormone, or indeed any biologically active substance, acting on its target cell, causes a change in the chemical activity of that cell that mediates the physiological effect of the hormone. By cytochemical methods one can assess such changes in the target cells even if these constitute only a small part of the target-organ; thus such methods are ideally suited to measuring chemical changes of this sort induced by the hormone. Such cytochemical bioassay of polypeptide hormones, done as "within-animal" assays, are about 1000-f0ld more sensitive than the equivalent radioimmunoassays and are as precise. Thus they have two advantages: (a) bioreactive hormone is measured rather than a composite of antigenic determinants characteristic of part of the hormone molecule and (b) their increased sensitivity allows discrimination between low normal and subnormal concentrations of the circulating hormone.

Gas-chromatographic determination of nanogram amounts of enantiomers of nortilidine, a main metabolite of tilidine, in biological specimens.

1978 ◽  
Vol 24 (4) ◽  
pp. 692-697 ◽  
Author(s):  
H Hengy ◽  
K O Vollmer ◽  
V Gladigau
Keyword(s):  
Intravenous Administration ◽  
Chromatographic Determination ◽  
Optical Isomers ◽  
Sensitive Detector ◽  
Main Metabolite ◽  
Chiral Reagent ◽  
The Individual ◽  
Derivatives Of ◽  
Sensitive Method

Abstract We report a specific and sensitive method for determination of the individual optical isomers of nortilidine, a main metabolite of tilidine, with the aid of a nitrogen-sensitive detector. With N-trifluoroacetyl-L-leucyl chloride as chiral reagent, the diastereomeric derivatives of the nortilidine enantiomers could be separated and quantified in the nanogram range. Under these conditions, the enantiomers of bisnortilidine, another main metabolite of tilidine, were also separated. Investigations in rats with the enantiomers of tilidine and nortilidine indicated that no racemization occurs during N-demethylation in the organism. After oral and intravenous administration of 50 mg of tilidine.HCI to a human volunteer, identical concentrations of nortilidine enantiomers were found in the plasma.

scholarly journals Ratios among atmospheric trace gases together with winds imply exploitable information for bird navigation: a model elucidating experimental results

2013 ◽  
Vol 10 (11) ◽  
pp. 6929-6943 ◽  
Author(s):  
H. G. Wallraff
Keyword(s):  
Atmospheric Chemistry ◽  
Wind Direction ◽  
Spatial Information ◽  
Trace Gases ◽  
Atmospheric Trace Gases ◽  
Spatial Gradients ◽  
Home Site ◽  
Environmental Air ◽  
The Individual ◽  
At Home

Abstract. A model of avian goal-oriented navigation is described that is based on two empirical findings building a bridge from ornithology to atmospheric chemistry. (1) To orient their courses homeward from distant unfamiliar areas, homing pigeons require long-term exposure to undisturbed winds at the home site and olfactory access to the environmental air at home and abroad. (2) Above Germany, ratios among some atmospheric trace gases vary along differently oriented spatial gradients as well as depending on wind direction. The model emulates finding (1) by utilising the analysed air samples on which finding (2) is based. Starting with an available set of 46 omnipresent compounds, virtual pigeons determine the profile of relative weights among them at each of 96 sites regularly distributed around a central home site within a radius of 200 km and compare this profile with corresponding profiles determined at home under varying wind conditions. Referring to particular similarities and dissimilarities depending on home-wind direction, they try to estimate, at each site, the compass direction they should fly in order to approach home. To make the model work, an iterative algorithm imitates evolution by modifying sensitivity to the individual compounds stepwise at random. In the course of thousands of trial-and-error steps it gradually improves homeward orientation by selecting smaller sets of most useful and optimally weighted substances from whose proportional configurations at home and abroad it finally derives navigational performances similar to those accomplished by real pigeons. It is concluded that the dynamic chemical atmosphere most likely contains sufficient spatial information for home-finding over hundreds of kilometres of unfamiliar terrain. The underlying chemo-atmospheric processes remain to be clarified.

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