A fully automated method to quantitate total carbon dioxide in equine plasma by headspace GCMS.

Pre-race dosing of horses with alkalinising agents to manipulate performance has been evident in racing worldwide for over 30 years. To regulate the use of alkalinising agents, racing authorities adopted thresholds for total plasma carbon dioxide (TCO ) in racehorses. Traditionally, racing laboratories have measured plasma TCO using ion selective electrode (ISE) technology, with the Association of Official Racing Chemists (AORC) approving the use of only three ISE instruments for measurement.

Opposite fates of the purine metabolite allantoin under water and nitrogen limitations in bread wheat.

Degradation of nitrogen-rich purines is tightly and oppositely regulated under drought and low nitrogen supply in bread wheat. Allantoin is a key target metabolite for improving nitrogen homeostasis under stress. The metabolite allantoin is an intermediate of the catabolism of purines (components of nucleotides) and is known for its housekeeping role in nitrogen (N) recycling and also for its function in N transport and storage in nodulated legumes.

Comparative metabolic and ionomic profiling of two cultivars of Stevia rebaudiana Bert. (Bertoni) grown under salinity stress.

This study provides a comprehensive investigation on the impact of increasing NaCl concentrations on hydroponically grown Stevia rebaudiana cultivars (Shoutian-2 and Fengtian). Growth parameters including plant height, biomass and physiological responses including osmotic potential were measured. In addition, the levels of steviol glycosides, elements and primary metabolites were measured and statistically evaluated.

Quantification of Sugars and Organic Acids in Biological Matrices Using GC-QqQ-MS.

Gas chromatography coupled with triple quadrupole mass spectrometry (GC-QqQ-MS) can be used to accurately quantify endogenous small molecules extracted from biological samples such as plants and human fluids including sera and urine. In order to quantify primary metabolites typically from central carbon metabolism such as sugars from glycolysis and the pentose phosphate pathway; and organic acids involved in the tricarboxylic acid (TCA) cycle; polar endogenous metabolites must be extracted from the samples of interest, chemically derivatized and quantified against a linear calibration curve to a corresponding authentic standard. This chapter describes how to quantify a combination of 48 primary metabolites belonging to classes of sugars, sugar alcohols, sugar acids, sugar phosphates, and organic acids using a robust, optimized, multiple reaction monitoring (MRM)-based GC-QqQ-MS method.

Epidermal bladder cells confer salinity stress tolerance in the halophyte quinoa and Atriplex species.

Epidermal bladder cells (EBCs) have been postulated to assist halophytes in coping with saline environments. However, little direct supporting evidence is available. Here, Chenopodium quinoa plants were grown under saline conditions for 5 weeks.

From common to rare Zingiberaceae plants - A metabolomics study using GC-MS.

Zingiberaceae plants, commonly known as gingers, have been popular for their medicinal and culinary uses since time immemorial. In spite of their numerous health-promoting applications, many Zingiberaceae plants still receive no scientific attention. Moreover, existing reports mostly focused only on the Zingiberaceae rhizomes.

Root spatial metabolite profiling of two genotypes of barley (Hordeum vulgare L.) reveals differences in response to short-term salt stress.

Barley (Hordeum vulgare L.) is the most salt-tolerant cereal crop and has excellent genetic and genomic resources. It is therefore a good model to study salt-tolerance mechanisms in cereals.

Quantitative profiling of polar primary metabolites of two chickpea cultivars with contrasting responses to salinity.

This study reports a GC-QqQ-MS method for the quantification of forty-eight primary metabolites from four major classes (sugars, sugar acids, sugar phosphates, and organic acids) which can be applied to a number of biological systems. The method was validated in terms of linearity, reproducibility and recovery, using both calibration standards and real samples. Additionally, twenty-eight biogenic amines and amino acids were quantified using an established LC-QqQ-MS method.

Flicker light-induced retinal vasodilation is unaffected by inhibition of epoxyeicosatrienoic acids and prostaglandins in humans.

Purpose: To investigate the role of epoxyeicosatrienoic acids (EETs) and prostaglandins (PGs) in retinal blood vessel calibers and vasodilation during flicker light stimulation in humans.

Methods: Twelve healthy nonsmokers participated in a balanced crossover study. Oral fluconazole 400 mg and dispersible aspirin 600 mg were used to inhibit production of EETs and PGs, respectively.

A robust GC-MS method for the quantitation of fatty acids in biological systems.

Fatty acids (FAs) are involved in a wide range of functions in biological systems. It is important to measure the exact amount of fatty acids in biological matrices in order to determine the level of fatty acids and understand the role they play. The ability to quantify fatty acids in various systems, especially plant species and microbes has recently paved the way to the mass production of pharmaceuticals and energy substitutes including biodiesel.

A quantitative analysis of microalgal lipids for optimization of biodiesel and omega-3 production.

The lipid characteristics of microalgae are known to differ between species and change with growth conditions. This work provides a methodology for lipid characterization that enables selection of the optimal strain, cultivation conditions, and processing pathway for commercial biodiesel production from microalgae. Two different microalgal species, Nannochloropsis sp.