Gas chromatography–mass spectrometric analysis of bonded long chain fatty acids in a single zebrafish egg by ultrasound-assisted one-step transmethylation and extraction

Rapid high performance liquid chromatography-high resolution mass spectrometry methodology for multiple prenol lipids analysis in zebrafish embryos

The analysis of lipid molecules in living organism is an important step in deciphering metabolic pathways. Recently, the zebrafish has been adopted as a valuable animal model system to perform in vivo metabolomics studies, however limited methodologies and protocols are currently available to investigate zebrafish lipidome and even fewer to analyze specific classes of lipids. Here we present an HPLC-HRMS based method to rapidly measure multiple prenol lipid molecules from zebrafish tissues. In particular, we have optimized our method for concurrent detection of ubiquinones (Coenzyme Q6, Coenzyme Q9, Coenzyme Q10), cholesterol, vitamin E (α-tocopherol), vitamin K1 and vitamin K2. The purpose of this study was to compare different ionization modes, mobile phases and stationary phases in order to optimize lipid molecules separation. After HPLC-HRMS parameters selection, several extraction conditions from zebrafish embryos were evaluated. We assessed our methodology by quantitation of analytical recovery on zebrafish extracts from wild-type or zebrafish mutants (barolo) affected by impaired biosynthesis of ubiquinones.

[Rapid determination of fatty acids in Ranunculus ternatus Thunb by microwave-ultrasonic synergistic one-step extraction-derivatization and gas chromatography-mass spectrometry]

A rapid and simple microwave-ultrasonic synergistic one-step extraction-derivatization (MUED) method and gas chromatography-mass spectrometry was established for the determination of low content fatty acids (FAs) profile in Ranunculus ternatus Thunb. The critical experimental parameters for MUED method were optimized with response surface methodology by taking the chromatographic peak areas of total FAs as a major response index. The best technological parameters were determined as 5.0 g of Ranunculus ternatus Thunb. powder, 50.0 mL of n-hexane, 500 W of microwave power, 50 degree C of reaction temperature, 0.30 g of catalyst (KOH), 4.0 mL of derivatization reagent (methanol) and the time of extraction-derivatization of 8 min. The contents of individual FAs were quantified by internal standard method. The results showed that the chromatographic peak areas of the total FAs and the total unsaturated FAs contents obtained with MUED were (3.327 +/- 0.023) x 10(7) (n = 3) and (13.59 +/- 0.30) mg/g (n = 3) respectively. They were markedly higher than those obtained by the conventional method which were (2.410 +/- 0.036) x 10(7) (n = 3) and (12.05 +/- 0.34) mg/g (n = 3) respectively. The MUED method simplified the complicated sample handling steps, shortened the sample preparation time, reduced the cost of analysis, and improved the extraction and derivatization efficiency of the lipids, especially weakened the oxidization and decomposition of the unsaturated FAs. The simplicity, speed and practicability suggest the proposed method has significant potential for the determination of lowcontent FAs in herbal medicines.

Microwave-assisted one-step extraction-derivatization for rapid analysis of fatty acids profile in herbal medicine by gas chromatography-mass spectrometry

A rapid and practical microwave-assisted one-step extraction-derivatization (MAED) method was developed for gas chromatography-mass spectrometry analysis of fatty acids profile in herbal medicine. Several critical experimental parameters for MAED, including reaction temperature, microwave power and the amount of derivatization reagent (methanol), were optimized with response surface methodology. The results showed that the chromatographic peak areas of total fatty acids and total unsaturated fatty acids content obtained with MAED were markedly higher than those obtained by the conventional Soxhlet or microwave extraction and then derivatization method. The investigation of kinetics and thermodynamics of the derivatization reaction revealed that microwave assistance could reduce activation energy and increase the Arrhenius pre-exponential factor. The MAED method simplified the sample preparation procedure, shortened the reaction time, but improved the extraction and derivatization efficiency of lipids and reduced ingredient losses, especially for the oxidization and isomerization of unsaturated fatty acids. The simplicity, speed and practicality of this method indicates great potential for high throughput analysis of fatty acids in natural medicinal samples.

Chemical and genetic probes for analysis of protein palmitoylation

Reversible protein palmitoylation is one of the most important posttranslational modifications that has been implicated in the regulation of protein signaling, trafficking, localizing and enzymatic activities in cells and tissues. In order to achieve a precise understanding of mechanisms and functions of protein palmitoylation as well as its roles in physiological processes and disease progression, it is necessary to develop techniques that can qualitatively and quantitatively monitor the dynamic protein palmitoylation in vivo and in vitro. This review will highlight recent advances in both chemical and genetic encoded probes that have been developed for accurate analysis of protein palmitoylation, including identification and quantification of acyl moieties and palmitoylated proteins, localization of amino acid residues on which acyl moieties are attached, and imaging of cellular distributions of palmitoylated proteins. The role of major techniques of fluorescence microscopy and mass spectrometry in facilitating the analysis of protein palmitoylation will also be explored.