Production and roles of IAA and ABA during development of superior and inferior rice grains

2020 ◽  
Vol 47 (8) ◽  
pp. 716 ◽  
Author(s):  
Heather M. Nonhebel ◽  
Karina Griffin

Current understanding of the role of plant hormones during cereal grain filling is confounded by contradictory reports on hormone production that is based on poor methodology. We report here on the accurate measurement of indole-3-acetic acid (IAA) and abscisic acid (ABA) by combined liquid chromatography-tandem mass spectrometry in multiple reaction-monitoring mode with heavy isotope labelled internal standards. ABA and IAA contents of superior versus inferior rice grains (ABA maxima 159 ng g–1 FW and 109 ng g–1 FW, IAA maxima 2 µg g–1 FW and 1.7 µg g–1 FW respectively) correlated with the expression of biosynthetic genes and with grain fill. Results confirm that grain ABA is produced primarily by OsNCED2(5), but suggest that ABA import and metabolism also play important roles in ABA regulation. The IAA content of grains is primarily influenced by OsYUC9 and OsYUC11. However, the distinct expression profile of OsYUC12 suggests a specific role for IAA produced by this enzyme. Co-expression of OsYUC12 with OsIAA29 indicates their involvement in a common signalling pathway. Co-expression and cis-element analysis identified several aleurone-specific transcriptional regulators as well as glutelin as strong candidates for detailed investigation for direct regulation by the auxin-signalling pathway.

Molecules ◽  
2019 ◽  
Vol 24 (24) ◽  
pp. 4618 ◽  
Author(s):  
Paweł Kubica

The content of tobacco-specific nitrosamines (TSNAs) possessing carcinogenic properties has been an important area of research since replacement liquids were introduced for e-cigarettes. A method for determining N′-nitrosonornicotine (NNN), 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone (NNK), N′-nitrosoanatabine (NAT), and N′-nitrosoanabasine (NAB) in replacement liquids for electronic cigarettes was developed using liquid chromatography–tandem mass spectrometry with electrospray ionisation (HPLC-ESI-MS/MS) in the multiple reaction monitoring mode. The sample preparation of replacement liquids was accomplished via the ultrasound-assisted solvent extraction of a porous membrane packed sample. The sample preparation proved to be successful in extracting the analytes, with recoveries from 87% to 105%, with coefficients of variation < 4.9%. Moreover, the linearity and limits of detection and quantitation (LOD, LOQ), together with repeatability and accuracy, were determined for the developed method. The proposed sample preparation and developed chromatographic method were successfully applied to the determination of TSNAs in 9 replacement liquid samples. The NNK and NNN were found to be most frequently detected (89 and 67%, respectively), with concentration ranges from 1.2–54.3 ng/mL and 4.1–30.2 ng/mL, respectively, while NAT was detected with frequency of 22% with range 1.7–2.5 ng/mL and NAB were found to be below the LOD in all samples.


Author(s):  
Yufeng Ni ◽  
Yujia Zhang ◽  
Chong Zou ◽  
Li Ding

A rapid and reproducible liquid chromatography-tandem mass spectrometry (LC-MS/MS) method was developed and validated to simultaneously determine sacubitril, valsartan and a metabolite of sacubitril (LBQ657) in human plasma using sacubitril-d4 and valsartan-d3 as the internal standards. Following protein precipitation, the analytes were operated on an Ultimate® XB-C18 column (2.1 × 50 mm, 3.5 μm, Welch) with a gradient elution with acetonitrile, and 5 mM ammonium acetate and 0.1% formic acid in water as the mobile phase. The detection was performed on a Triple Quad™ 4000 mass spectrometer coupled with an electrospray ionization source (ESI) under positive-ion multiple reaction monitoring mode. The linearities are 2.00-4000, 5.00-10000 and 5.00-10000 ng mL-1 for sacubitril, valsartan and LBQ657, respectively. The accuracy and precision of intra- and inter-day, dilution accuracy, recovery and stability of the method were all within the acceptable limits and no matrix effect or carryover was observed. The suitability of the method was successfully demonstrated in terms of the quantification of sacubitril, valsartan and LBQ657 in plasma samples collected from healthy Chinese volunteers in a clinical trial.


Author(s):  
Revathi Naga Lakshmi Ponnuri ◽  
Prahlad Pragallapati ◽  
Ravindra N ◽  
Venkata Basaveswara Rao Mandava

  Objective: The main objective of the work was to develop a straightforward, fast and selective liquid chromatography/tandem mass spectrometry (LC-MS/MS) assay for determination of pioglitazone (PG), keto pioglitazone (KPG), and hydroxy pioglitazone (HPG) in human plasma and to validate as per recent guidelines.Methods: Analyte and the internal standard (IS) were extracted from plasma through liquid-liquid extraction and chromatographed on a Xterra RP18, 100×4.6, 5 μ column using methanol: acetonitrile mixture and 10 mM Ammonium formate buffer (70:30, v/v) as the mobile phase at a flow rate of 0.7 mL/min. The API-3200 Q Trap LC-MS/MS instrument in multiple reaction monitoring mode was used for detection. Diphenhydramine was utilized as IS.Results: The linearity was established in the concentration range of 20.15-1007.58 ng/mL for PG, 20.35-1017.58 ng/mL for KPG, and 19.68-491.22 ng/mL for HPG in human plasma. All the validation parameters were well within the acceptance limits.Conclusion: A new simple LC-MS/MS method was developed for the determination of PG, KPG, and HPG in human plasma. This method can be easily applied for the estimation of pharmacokinetic parameters of PG, KPG, and HPG.


2019 ◽  
Vol 26 (1) ◽  
pp. 63-77
Author(s):  
Shencong Lv ◽  
Henghui Wang ◽  
Yong Yan ◽  
Miaohua Ge ◽  
Jian Guan

A simple, rapid, and efficient liquid chromatography tandem mass spectrometry (LC–MS/MS) method, operated in electrospray ionization and quadrupole linear ion trap modes, has been developed for the identification and structural characterization of aflatoxins in peanuts and its derivative products or bean sauce. Samples (5 g) were extracted with acetonitrile/water/formic acid (79:20:1, v/v). After centrifugation and dilution, the extracts were separated on a C18 analytical column by gradient elution (acetonitrile/0.2% formic acid) and analyzed by UPLC–MS/MS. External calibration was used for qualification. The developed multiple reaction monitoring–information-dependent acquisition–enhanced product ion method enabled quantification and confirmation of the analytes in a single run. Enhanced product ion mode was used for qualitative analysis, while multiple reaction monitoring mode was used for quantitative analysis. An in-house library was constructed for identification. Calibration curves showed good linearity with correlation coefficients (r) higher than 0.994. Limits of detection were determined to be below 0.26 µg kg−1 for most analytes. The recoveries for those substances were in the acceptable range of 80.2%–119.1%. A new LC–MS3 method was established for further confirmation. One pickled pepper peanut was found to contain aflatoxins B1, B2, and G1 with contents of 90.93, 26.64, and 1.92 µg kg−1, respectively.


2013 ◽  
Vol 96 (3) ◽  
pp. 657-662 ◽  
Author(s):  
Shao-Ying Liu ◽  
Quan Jin ◽  
Xi-Hui Huang ◽  
Guo-Nian Zhu

Abstract An improved analytical method was developed for simultaneous quantification of seven carbamates in milk by ultra-performance LC combined with electrospray ionization triple quadrupole tandem mass spectrometry in the multiple reaction monitoring mode. Samples were extracted and purified using a modified Quick, Easy, Cheap, Effective, Rugged, and Safe (QuEChERS) method. The LOQs ranged from 0.033 to 0.23 μg/kg; reasonable recoveries (85.4 to 110.9%) of the seven carbamates in milk were demonstrated at different spike levels. The developed analytical method would be appropriate for the routine, high throughput, high sensitivity quantification of the seven carbamates using modified QuEChERS pretreatment.


Molecules ◽  
2019 ◽  
Vol 24 (7) ◽  
pp. 1403 ◽  
Author(s):  
Xiaoyong Zheng ◽  
Feng Feng ◽  
Xiunan Jiang ◽  
Jieying Qiu ◽  
Xiaojun Cai ◽  
...  

Gomisin D, a lignan compound isolated from Fructus Schisandra, is a potential antidiabetic and anti-Alzheimer’s agent. Recently, gomisin D was used as a quality marker of some traditional Chinese medicine (TCM) formulas. In this study, a rapid ultra-performance liquid chromatography/tandem mass spectrometry method (UPLC-MS/MS) was developed and validated to quantify gomisin D in rat plasma for a pharmacokinetic and bioavailability study. Acetonitrile was used to precipitate plasma proteins. Separations were performed on a BEH C18 column with a gradient mobile phase comprising of acetonitrile and water (0.1% formic acid). An electrospray ionization source was applied and operated in the positive ion mode. The multiple reaction monitoring mode (MRM) was utilized to quantify gomisin D and nomilin (internal standard, IS) using the transitions of m/z 531.2 → 383.1 and m/z 515.3 → 161.0, respectively. The calibration curve was linear over the working range from 1 to 4000 ng/mL (R2 = 0.993). The intra- and interday precision ranged from 1.9% to 12.9%. The extraction recovery of gomisin D was in the range of 79.2–86.3%. The validated UPLC-MS/MS method was then used to obtain the pharmacokinetic characteristics of gomisin D after intravenous (5 mg/kg) and intragastric (50 mg/kg) administration to rats. The bioavailability of gomisin D was 107.6%, indicating that this compound may become a promising intragastrical medication. Our results provided useful information for further preclinical studies on gomisin D.


2020 ◽  
Vol 58 (10) ◽  
pp. 922-928
Author(s):  
Jing Zhang ◽  
Quan Wen ◽  
Meng-ying Zhou ◽  
Chen-cong Zhong ◽  
Yulin Feng ◽  
...  

Abstract Chimonanthi Radix (CR) is widely used in the treatment of influenza in China. Extensive studies revealed that the major bioactive constituents of CR were coumarins. However, pharmacokinetic study of coumarins in CR has not been fully studied. The purpose of this study was to establish a convenient and effective high-performance liquid chromatography–tandem mass spectrometry method that was used to simultaneously determine scopoletin, scopolin and isofraxidin in rat plasma after oral administration of CR extract using xanthotoxin as the internal standard. The chromatographic separation was carried out on a COSMOCORE C18 column (100 × 2 mm, 2.6 μm), using gradient elution with the mobile phase consisting of 0.1% formic acid (A) and acetonitrile (B). Three coumarins and IS were quantified by positive ion electrospray ionization in multiple reaction monitoring mode. The method was fully validated in terms of specificity, accuracy, precision (intra- and inter-day), matrix effect, recovery as well as the stability of the analytes under various conditions. The results could provide further research foundation for anti-influenza mechanism of three coumarins in CR.


Author(s):  
Xi Luo ◽  
Xiu Jin Zhang ◽  
Wen Ling Zhu ◽  
Jin Ling Yi ◽  
Wen Gang Xiong ◽  
...  

Abstract A high performance liquid chromatography–tandem mass spectrometry assay for the determination of afatinib (AFT) in human plasma was established. A simple sample preparation of protein precipitation was used and separation was achieved on a C18 column by the gradient mixture of mobile Phase A of water (containing 0.1% ammonia) and the mobile Phase B of acetonitrile and water (V:V = 95:5, containing 0.2% ammonia). The multiple reaction monitoring mode was used to monitor the precursor-to-production transitions of m/z 486.2 → m/z 371.4 for AFT and m/z 492.2 → m/z 371.3 for AFT-d6 (internal standard) at positive ionization mode. The calibration curve ranged from 0.100 to 25.0 ng·mL−1 and the correlation coefficient was greater than 0.99. The intra- and inter-batch precision was less than or equal to 10.0%. Accuracy determined at four concentrations was in the range of 92.3–103.3%. In summary, our method was sensitive, simple and reliable for the quantification of AFT and was successfully applied to a bioequivalence study.


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