Relative quantification of phenolic compounds in exocarp-mesocarp and endocarp of sumac (Toxicodendron vernicifluum) combined with transcriptome analysis provides insights into glycosylation of flavonoids and biflavonoid biosynthesis.

The pericarp of fruit can be differentiated into endocarp, mesocarp, and exocarp. To explore the differences in gene expression and metabolites in different tissues of the pericarp, the fruits of sumac (Toxicodendron vernicifluum) were separated into endocarp and mesocarp-exocarp. The metabolites and transcriptome of exocarp-mesocarp and endocarp of Toxicodendron vernicifluum were analyzed by HPLC-QTOF-MS/MS and RNA sequencing, respectively. A total of 52 phenolic compounds were identified, including 3 phenylpropane derivatives, 10 urushiol compounds and 39 flavonoids. The exocarp-mesocarp contained more urushiol compounds and flavonoid glycosides while the endocarp contained more biflavonoids, such as rhusflavone and dihydromorelloflavone. The characteristic component of endocarp was rhusflavone and the characteristic component of exocarp-mesocarp was urushiol (triene). Most of the genes involved in flavonoid synthesis pathway were upregulated in endocarp compared with exocarp-mesocarp and positively correlated with the content of flavonoids. The candidate genes related to the synthesis of components of flavonoid glycosides and biflavonoids were screened. Metabolomic and transcriptomic analyses provide new insights into the synthesis and distribution of flavonoid glycosides and biflavonoids in the fruits of Toxicodendron vernicifluum.

Simultaneous Quantitation of Clevidipine and Its Active Metabolite H152/81 in Human Whole Blood by LC-MS/MS: Application to Bioequivalence Study.

Clevidipine is an ultrashort-acting dihydropyridine calcium antagonist, which can control blood pressure accurately. It is necessary to develop a liquid chromatography-tandem mass spectrometry (LC-MS/MS) method to quantitate clevidipine and its active metabolite H152/81 for clinical pharmacokinetic study and therapeutic drug monitoring. Liquid-liquid extraction was used for sample preparation, and clevidipine-d7 and H152/81-13C-d3 were chosen as the isotope internal standard. The chromatographic separation was performed on an ACE Excel 2 Phenyl column (50 × 2.1 mm). Mass quantification was carried out on the multiple reaction monitoring of the transitions of m/z 473.1→338.1, 480.1→338.1, 356.0→324.0, and 362.2→326.2 for clevidipine, clevidipine-d7, H152/81, and H152/81-13C-d3. The validated method gave an excellent linearity over a concentration range of 0.1-30 ng/ml for clevidipine and 2-600 ng/ml for H152/81. Other fully validated content such as accuracy, precision, extraction recovery, matrix effect, and stability were also investigated and showed satisfactory results. It was strongly recommended that whole blood is the first choice for clinical bioanalysis. Using whole blood for sample analysis can reduce the whole blood collection volume (1 ml vs. 4 ml) and shorten the time from sample collection to storage to 5 min, and there is no centrifugation process and precooling in the ice water bath, which can further reduce the instability caused by exposure. The method was successfully applied to a bioequivalence study of clevidipine butyrate-injectable emulsion.

Alkaline hydrothermal liquefaction of swine carcasses to bio-oil.

It is imperative that swine carcasses are disposed of safely, practically and economically. Alkaline hydrothermal liquefaction of swine carcasses to bio-oil was performed. Firstly, the effects of temperature, reaction time and pH value on the yield of each liquefaction product were determined. Secondly, liquefaction products, including bio-oil and solid residue, were characterized. Finally, the energy recovery ratio (ERR), which was defined as the energy of the resultant products compared to the energy input of the material, was investigated. Our experiment shows that reaction time had certain influence on the yield of liquefaction products, but temperature and pH value had bigger influence on the yield of liquefaction products. Yields of 62.2wt% bio-oil, having a high heating value of 32.35MJ/kg and a viscosity of 305cp, and 22wt% solid residue were realized at a liquefaction temperature of 250°C, a reaction time of 60min and a pH value of 9.0. The bio-oil contained up to hundreds of different chemical components that may be classified according to functional groups. Typical compound classes in the bio-oil were hydrocarbons, organic acids, esters, ketones and heterocyclics. The energy recovery ratio (ERR) reached 93.63%. The bio-oil is expected to contribute to fossil fuel replacement in stationary applications, including boilers and furnaces, and upgrading processes for the bio-oil may be used to obtain liquid transport fuels.

In situ reactive extraction of cottonseeds with methyl acetate for biodiesel production using magnetic solid acid catalysts.

A magnetic solid acid catalyst S2O8(2)(-)/ZrO2-TiO2-Fe3O4 was prepared by coprecipitation and impregnation methods and its catalytic activity was investigated for the reactive extraction of cottonseeds with methyl acetate to produce biodiesel. The physicochemical properties of the catalyst were characterized in detail. The influences of Zr/Ti molar ratio and calcination temperature on the catalytic performance were investigated. Moreover, optimization of the reactive extraction process was performed using response surface methodology coupled with central composite design. The catalyst with a Zr/Ti molar ratio of 3/1 calcined at 550°C showed the best activity. An optimum biodiesel yield of 98.5% was obtained under the reaction temperature of 50°C, catalyst amount of 21.3wt.%, methyl acetate/seed ratio of 13.8ml/g and 10.8h of reaction time. Reuse of this catalyst indicated that it had steady catalytic activity and high recovery rate which could be a promising catalyst for biodiesel production from oilseeds.

Ion-pairing chromatography on a porous graphitic carbon column coupled with time-of-flight mass spectrometry for targeted and untargeted profiling of amino acid biomarkers involved in Candida albicans biofilm formation.

BACKGROUND: Candida albicans, the most common fungal pathogen related to colonization and biofilm formation on the surfaces of indwelling medical devices, shows high resistance to the most commonly used antifungal drugs. In this study, an ion-pairing chromatography-porous graphitic carbon column coupled with a time-of-flight mass spectrometry (IP-PGC-TOF/MS) system was developed for targeted and untargeted profiling of metabolites involved in biofilm and planktonic growth of C. albicans. Using untargeted profiling analysis, 16 differential metabolites were screened and identified as potential biomarkers, most of which were amino acids or related compounds. Based on untargeted profiling analysis, targeted quantitative analysis of 22 amino acids was established and carefully evaluated using stable isotope-labeled internal standards. Among them, 9 amino acids that were not screened by untargeted profiling were further characterized as new biomarkers. Finally, a total of 25 potential biomarkers were screened using the combined targeted and untargeted strategy, among which 16 were characterized for the first time. Our results confirmed that amino acid metabolism and polyamine metabolism were at a high level in biofilms, except for some new biomarkers including ornithine, arginine and proline that were directly related to ornithine. Further experiments were carried out on the ornithine decarboxylase-negative (spe1Δ) mutant, and the results showed that the consumption of ornithine for putrescine biosynthesis has a significant impact on biofilm formation and may prove to be a drug target for resolving drug resistance of C. albicans. This study provides a systematic view of changes in amino acid metabolism during C. albicans biofilm formation by a combination of targeted and untargeted profiling using an original IP-PGC-TOF/MS method. It is a feasible approach for characterizing subtle variations and screening novel biomarkers from the microbial metabolome.

Effect of amphotericin B on the metabolic profiles of Candida albicans.

Amphotericin B (AmB) is a polyene antifungal drug widely used for systemic fungal infections. In this study, a metabonomic method using gas chromatography-mass spectrometry (GC/MS) was developed to characterize the metabolic profiles of Candida albicans cells exposed to AmB. Thirty-one differentially produced metabolites between AmB-treated and the control groups were identified, among which 10 metabolites were upregulated and 21 metabolites were downregulated. These differentially produced metabolites were mainly involved in polyamines synthesis, tricarboxylic acid (TCA) cycle, oxidative stress, glutathione metabolism, lipid synthesis and glycolysis. Further experiments showed that the polyamines including putrescine, spermidine, and spermine played an important role in the sensitivity of C. albicans cells upon AmB treatment, and combined use of AmB and inhibitors of polyamine biosynthesis pathway might be a potential antifungal strategy. This study provided a systemic view of the metabolic pattern in C. albicans upon exposure to AmB, which shed new light on the mechanisms of action of antifungal agents.

Liquid chromatography coupled with time-of-flight and ion trap mass spectrometry for qualitative analysis of herbal medicines.

With the expansion of herbal medicine (HM) market, the issue on how to apply up-to-date analytical tools on qualitative analysis of HMs to assure their quality, safety and efficacy has been arousing great attention. Due to its inherent characteristics of accurate mass measurements and multiple stages analysis, the integrated strategy of liquid chromatography (LC) coupled with time-of-flight mass spectrometry (TOF-MS) and ion trap mass spectrometry (IT-MS) is well-suited to be performed as qualitative analysis tool in this field. The purpose of this review is to provide an overview on the potential of this integrated strategy, including the review of general features of LC-IT-MS and LC-TOF-MS, the advantages of their combination, the common procedures for structure elucidation, the potential of LC-hybrid-IT-TOF/MS and also the summary and discussion of the applications of the integrated strategy for HM qualitative analysis (2006-2011). The advantages and future developments of LC coupled with IT and TOF-MS are highlighted.