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67 results for “Chemical identification”
Chemical variations in Quercus pollen as a tool for taxonomic identification: implications for long-term ecological and biogeographical research
<p><strong>Aim</strong> </p> <p>Fossil pollen is an important tool for understanding biogeographic patterns in the past, but the taxonomic resolution of the fossil-pollen record may be limited to genus or even family level. Chemical analysis of pollen grains has the potential to increase the taxonomic resolution of pollen, but present-day chemical variability is poorly understood. This study aims to investigate whether a phylogenetic signal is present in the chemical variations of <em>Quercus</em> L. pollen and to assess the prospects of chemical techniques for identification in biogeographic research.</p> <p><strong>Location</strong> </p> <p>Portugal</p> <p><strong>Taxon</strong> </p> <p>Six taxa (five species, one subspecies) of <em>Quercus</em> L., <em>Q. faginea, Q. robur, Q. robur</em> ssp. <em>estremadurensis, Q. coccifera, Q. rotundifolia</em> and <em>Q. suber</em> belonging to three sections: <em>Cerris, Ilex</em>, and <em>Quercus</em> (<a href="https://www.biorxiv.org/content/10.1101/761148v2#ref-13">Denk, Grimm, Manos, Deng, & Hipp, 2017</a>)</p> <p><strong>Methods</strong> </p> <p>We collected pollen samples from 297 individual <em>Quercus</em> trees across a 4° (∼450 km) latitudinal gradient and determined chemical differences using Fourier-transform infrared spectroscopy (FTIR). We used canonical powered partial least-squares regression (CPPLS) and discriminant analysis to describe within- and between-species chemical variability.</p> <p><strong>Results</strong> </p> <p>We find clear differences in the FTIR spectra from <em>Quercus</em> pollen at the section level (<em>Cerris</em>: ∼98%; <em>Ilex</em>: ∼100%; <em>Quercus</em>: ∼97%). Successful discrimination is based on spectral signals related to lipids and sporopollenins. However, discrimination of species within individual <em>Quercus</em> sections is more difficult: overall, species recall is ∼76% and species misidentifications within sections lie between 18% and 31% of the test-set.</p> <p><strong>Main Conclusions</strong> </p> <p>Our results demonstrate that subgenus level differentiation of <em>Quercus</em> pollen is possible using FTIR methods, with successful classification at the section level. This indicates that operator-independent FTIR approaches can surpass traditional morphological techniques using the light microscope. Our results have implications both for providing new insights into past colonisation pathways of <em>Quercus</em>, and likewise for forecasting future responses to climate change. However, before FTIR techniques can be applied more broadly across palaeoecology and biogeography, our results also highlight a number of research challenges that still need to be addressed, including developing sporopollenin-specific taxonomic discriminators and determining a more complete understanding of the effects of environmental variation on pollen-chemical signatures in <em>Quercus</em>.</p>
Underlying data for Slimani et al. Identification of dominant hydrogeochemical processes for groundwaters in the Algerian Sahara supported by inverse modeling of chemical and isotopic data
<p>The data hereafter underlie the paper by Slimani et al. doi:10.5194/hess-20-1-2016,</p> <p>appeared to Hydrol. Earth Syst. Sci., 20, 1-23, 2016.</p> <p> </p> <p> </p> <p>1. File Tableaux_data.xls</p> <p> </p> <p>This is an Excel sheet file. It contains:</p> <p>- raw analytical data, mostly in mg/L;</p> <p>- data converted in mmol/L;</p> <p>- data corrected from the defect of cations - anions balance; the correction is made proportionally.</p> <p>- the previous data completed with logarithms of activities, computed by Phreeqc, </p> <p>for calcium, sulfate, carbonate and water; those data are used to plot equilibrium diagrams for calcite and gypsum (figure 6);</p> <p>- for Phreatic aquifer only, saturation indexes for halite, anhydrite, calcite, dolomite and gypsum, along with distance from south to north, used in figure 7.</p> <p>2. Directory Phreeqc_res</p> <p>Contains the input file with all samples from CI, CT and Phr in a single file, and the selected output file.</p> <p>All calculations were made with version phreeqc-3.1.2 and database sit.dat.</p> <p>3. Directory Inverse models</p> <p>This directory contains inverse models for computing transformations:</p> <p>- from CI (average) to CT (average):</p> <p>- from CT (average) to Phr (pole I, average);</p> <p>- from pure water to Phr (pole II, sample P036);</p> <p>- for mixing Phr pole I and II, and try to explain a sample typical of medium mixing ratio, sample P068.</p>
Chemical variations in Quercus pollen as a tool for taxonomic identification: implications for long-term ecological and biogeographical research
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Evaluation of Grain size, Amorphous Fe-Mn Oxides, and Chemical Weathering Effects on Geochemical Identification of the Yangtze River and Yellow River Sediments
<p>The data of grain size of the Yangtze River and Yellow River sediments are given in ds01.xls. Trace and REEs in the HCl- and AC-residual size-differentiated components of the Yangtze River and Yellow River sediments are given in ds02.xls. Major elements in the AC-residual <5 µm fractions of the Yangtze River and Yellow River sediments are given in ds03.xls. Major, trace, and REEs in the HCl- and AC-leachable fractions of the Yangtze River and Yellow River sediments are given in ds04.xls.</p>
European demonstration program on the effect-based and chemical identification and monitoring of organic pollutants in European surface waters - Supporting Material
<p>This data contains the supporting material of the publicaiton <a href="https://www.sciencedirect.com/science/article/pii/S0048969717314365">European demonstration program on the effect-based and chemical<br> identification and monitoring of organic pollutants in European surface waters.</a></p> <p> </p>
Fig. 7 in Chemical identification of 18-hydroxycarlactonoic acid as an LjMAX1 product and in planta conversion of its methyl ester to canonical and noncanonical strigolactones in Lotus japonicus
Fig. 7. Conversion of [13C]-18-OH-MeCLA to [13C]-5DS and [13C]-lotuslactone (LL) in the feeding experiment using L. japonicus roots. A) Conversion of [10–13C]-18-OH-MeCLA to [6′-13C]-5DS. LC-MS/MS analysis of [6′-13C]-5DS in root exudates after feeding [10–13C]-18-OHMeCLA. MRM chromatograms (left) and full-scan spectra of fragment ions (right). The MRM chromatograms of authentic 5DS (red: 331.15/217.00, blue: 331.15/97.00, green: 331.15/234.00, m/z in positive mode) and [6′-13C]-5DS (red: 332.15/218.00, blue: 332.15/97.00, green: 332.15/ 235.00, m/z in positive mode) are shown. B) Conversion of [10–13C]-18- HO-MeCLA to [6′-13C]-LL. LC-MS/MS analysis of [6′-13C]-LL in root exudates after feeding [10–13C]-18-OH-MeCLA. MRM chromatograms (left) and full-scan spectra of fragment ions (right). The MRM chromatograms of authentic LL (red: 373.00/276.00, blue: 373.00/244.00, green: 373.00/ 216.00, m/z in positive mode) and [6′-13C]-LL (red: 374.00/277.00, blue: 374.00/245.00, green: 374.00/216.00, m/z in positive mode) are shown. (For interpretation of the references to color in this figure legend, the reader is referred to the Web version of this article.)
Fig. 8 in Chemical identification of 18-hydroxycarlactonoic acid as an LjMAX1 product and in planta conversion of its methyl ester to canonical and noncanonical strigolactones in Lotus japonicus
Fig. 8. The proposed biosynthetic pathway of 5DS and LL in L. japonicus. LjMAX1 catalyzes the oxidation of CL to 18-OH-CLA via CLA. (11R)-CL, CLA and 18- hydroxylated carlactonoates are precursors for 5DS and LL in L. japonicus. Solid arrows indicate confirmed pathways reported in previous studies and this study and dashed arrows indicate putative pathways. Blue letters indicate the position number. (For interpretation of the references to color in this figure legend, the reader is referred to the Web version of this article.)
Fig. 6 in Chemical identification of 18-hydroxycarlactonoic acid as an LjMAX1 product and in planta conversion of its methyl ester to canonical and noncanonical strigolactones in Lotus japonicus
Fig. 6. Conversion of [13C]-CLA to [13C]-5DS and [13C]-18-OH-CLA in the feeding experiment using L. japonicus roots. A) Conversion of [1-13CH]- 3 CLA to [8-13CH]-5DS. LC-MS/MS analysis of [8-13CH]-5DS in root exu3 3 dates after feeding [1-13CH]-CLA. MRM chromatograms (left) and full3 scan spectra of fragment ions (right). The MRM chromatograms of authentic 5DS (red: 331.15/217.00, blue: 331.15/97.00, green: 331.15/ 234.00, m/z in positive mode) and [8-13CH]-5DS (red: 332.15/218.00, 3 blue: 332.15/97.00, green: 332.15/235.00, m/z in positive mode) are shown. B) Conversion of [1-13CH]-CLA to [1-13CH]-18-OH-CLA. LC-MS/ 3 3 MS analysis of [1-13CH]-18-OH-CLA in root exudates after feeding 3 [1-13CH]-CLA. MRM chromatograms (left) and full-scan spectra of frag3 ment ions (right). Authentic 18-OH-CLA was prepared by feeding CL to recombinant Os900. MRM chromatograms of authentic 18-OH-CLA (red: 347.00/303.00, blue: 347.00/113.00, m/z in negative mode) and [1-13CH]-18-OH-CLA (red: 348.00/304.00, blue: 348.00/113.00, m/z in 3 negative mode) are shown. (For interpretation of the references to color in this figure legend, the reader is referred to the Web version of this article.)
Fig. 3 in Chemical identification of 18-hydroxycarlactonoic acid as an LjMAX1 product and in planta conversion of its methyl ester to canonical and noncanonical strigolactones in Lotus japonicus
Fig. 3. Synthetic scheme of 13C-labeled and unlabeled 18-OH-MeCLA. Asterisks indicate the position of 13C.
Fig. 2 in Chemical identification of 18-hydroxycarlactonoic acid as an LjMAX1 product and in planta conversion of its methyl ester to canonical and noncanonical strigolactones in Lotus japonicus
Fig. 2. Detection of 18-hydroxycarlactonoic acid (18-OH-CLA), 4DO and 5DS in CLA feeding experiment by recombinant LjMAX1 and Os900. CLA was incubated with recombinant yeast microsomes. Yeast microsomes having an empty vector and the expression vector pYeDP60-Os900 were used as a negative and a positive control, respectively. The extracts of the microsomes and authentic standard were analyzed by LC-MS/MS. The peak at 7.0 min was presumed to be 18-OH-CLA which may be converted artificially to 4DO and 5DS in the ion source of mass spectrometer, and detected in the MRM transitions for 4DO and 5DS (red: 331.15/216.00, blue: 331.15/97.00, green: 331.15/234.00, m/z in positive mode). (For interpretation of the references to color in this figure legend, the reader is referred to the Web version of this article.)
Fig. 1 in Chemical identification of 18-hydroxycarlactonoic acid as an LjMAX1 product and in planta conversion of its methyl ester to canonical and noncanonical strigolactones in Lotus japonicus
Fig. 1. Detection of carlactonoic acid (CLA), 4-deoxyorobanchol (4DO) and 5- deoxystrigol (5DS) in carlactone (CL) feeding experiment by recombinant Lotus japonicus MAX1 (LjMAX1) and Os900. CL was incubated with yeast microsomes. Yeast microsomes having an empty vector and the expression vector pYeDP60-Os900 were used as a negative and a positive control, respectively. The extracts of the microsomes and authentic standard were analyzed by LCMS/MS. MRM chromatograms of CLA (red: 331.10/69.00, blue: 331.10/ 113.00, m/z in negative mode), 4DO and 5DS (red: 331.15/216.00, blue: 331.15/97.00, green: 331.15/234.00, m/z in positive mode) are shown. (For interpretation of the references to color in this figure legend, the reader is referred to the Web version of this article.)
Fig. 28 in Glucosinolate structural diversity, identification, chemical synthesis and metabolism in plants
Fig. 28. The desulfation reaction catalyzed by sulfatase and used for derivatization in glucosinolate analysis.
Fig. 26 in Glucosinolate structural diversity, identification, chemical synthesis and metabolism in plants
Fig. 26. Mixed reaction catalyzed by "nitrilase" enzymes in crucifers. (A) The strict functional definition of nitrilase activity (E.C. 3.5.5.1). (B) A side reaction catalyzed by crucifer nitrilases to variable degree, probably caused by premature termination of the reaction after the first round of addition of water (Jandhyala et al., 2005), functionally defined as nitrile hydratase activity (E.C. 4.2.1.84).
Fig. 24 in Glucosinolate structural diversity, identification, chemical synthesis and metabolism in plants
Fig. 24. Examples of glucosinolate-derived indole phytoalexins and biosynthetic connections. Asterisks indicate a selected example of a labeling study of the brassinin biosynthesis (Pedras and Yaya, 2013). Question marks above some arrows signify steps that are demonstrated in vivo but for which specific enzymes are not yet known. MYR, myrosinase.
Fig. 25 in Glucosinolate structural diversity, identification, chemical synthesis and metabolism in plants
Fig. 25. Examples of crucifer non-indole phytoalexins derived from phenethyl isothiocyanate (Pedras and To, 2018). Question marks above some arrows signify steps that are demonstrated in vivo but for which specific enzymes are not yet known. MYR, myrosinase.
Fig. 22 in Glucosinolate structural diversity, identification, chemical synthesis and metabolism in plants
Fig. 22. Diverse products of allyl glucosinolate (GSL) depending on presence or absence of specifier proteins. The asterisks over the GSL, the isothiocyanate and the thiocyanate summarize the results of labeling studies (Benn, 1977; Rossiter et al., 2007) as previously detailed (Agerbirk and Olsen, 2012). All GSLs can form isothiocyanates, although some may be unstable, and nitriles. Only aliphatic GSLs with a terminal unsaturation can form epithionitriles. Only allyl GSL and two other GSLs (formally able to form a resonance-stabilized cation) can form organic thiocyanates. Some specifier proteins have other activities than those they are named from, as indicated in brackets. MYR, myrosinase; ESP, epithiospecifier protein; NSP, nitrile specifier protein; TFP, thiocyanate-forming protein.
Fig. 23 in Glucosinolate structural diversity, identification, chemical synthesis and metabolism in plants
Fig. 23. Participation of glutathione and a glutathione-S-transferase in forming a GSL-derived amine as a product of glucosinolate metabolism in intact cells, important for plant immunity. Question marks above some arrows signify steps that are demonstrated in vivo but for which specific enzymes are not yet known. Reactions are unbalanced. Amine and acid products are illustrated as the corresponding ammonium and carboxylate ions, as they would mainly exist at physiological pH. MYR, myrosinase.
Fig. 21 in Glucosinolate structural diversity, identification, chemical synthesis and metabolism in plants
Fig. 21. Selected examples of glucosinolate analogs synthesized for studying the interaction of natural glucosinolates with myrosinase.
Fig. 20 in Glucosinolate structural diversity, identification, chemical synthesis and metabolism in plants
Fig. 20. Synthesis of a glucosinolate epitope coupled to bovine serum albumin (BSA), intended for elicitation of an immune response.
Fig. 17 in Glucosinolate structural diversity, identification, chemical synthesis and metabolism in plants
Fig. 17. Two novel glucosinolates demonstrated by NMR and MS, but without conclusion of a single structure since the position of the methyl group is undetermined in each case.
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