The L-Glutamine/Ammonia (Rapid) test kit is a novel method for the specific, convenient, cost effective and rapid measurement and analysis of L-glutamine and ammonia in culture media/supernatants and other materials.

Extended cofactors stability. Dissolved cofactors stable for > 1 year at 4^oC.

A mutation in GDP-mannose pyrophosphorylase causes conditional hypersensitivity to ammonium, resulting in Arabidopsis root growth inhibition, altered ammonium metabolism, and hormone homeostasis.

Barth, C., Gouzd, Z. A., Steele, H. P. & Imperio, R. M. (2010).  Journal of Experimental Botany, 61(2), 379-394. Link to Article Read Abstract Ascorbic acid (AA) is an antioxidant fulfilling a multitude of cellular functions. Given its pivotal role in maintaining the rate of cell growth and division in the quiescent centre of the root, it was hypothesized that the AA-deficient Arabidopsis thaliana mutants vtc1-1, vtc2-1, vtc3-1, and vtc4-1 have altered root growth. To test this hypothesis, root development was studied in the wild type and vtc mutants grown on Murashige and Skoog medium. It was discovered, however, that only the vtc1-1 mutant has strongly retarded root growth, while the other vtc mutants exhibit a wild-type root phenotype. It is demonstrated that the short-root phenotype in vtc1-1 is independent of AA deficiency and oxidative stress. Instead, vtc1-1 is conditionally hypersensitive to ammonium (NH₄⁺). To provide new insights into the mechanism of NH₄⁺ sensitivity in vtc1-1, root development, NH₄⁺ content, glutamine synthetase (GS) activity, glutamate dehydrogenase activity, and glutamine content were assessed in wild-type and vtc1-1 mutant plants grown in the presence and absence of high NH₄⁺ and the GS inhibitor MSO. Since VTC1 encodes a GDP-mannose pyrophosphorylase, an enzyme generating GDP-mannose for AA biosynthesis and protein N-glycosylation, it was also tested whether protein N-glycosylation is affected in vtc1-1. Furthermore, since root development requires the action of a variety of hormones, it was investigated whether hormone homeostasis is linked to NH₄⁺ sensitivity in vtc1-1. Our data suggest that NH₄⁺ hypersensitivity in vtc1-1 is caused by disturbed N-glycosylation and that it is associated with auxin and ethylene homeostasis and/or nitric oxide signalling.

Metabolic profiling of hematopoietic stem and progenitor cells during proliferation and differentiation into red blood cells.

Daud, H., Browne, S., Al-Majmaie, R., Murphy, W. & Al-Rubeai, M. (2016). New Biotechnology, 33(1), 179-186. Link to Article Read Abstract An understanding of the metabolic profile of cell proliferation and differentiation should support the optimization of culture conditions for hematopoietic stem and progenitor cell (HSPC) proliferation, differentiation, and maturation into red blood cells. We have evaluated the key metabolic parameters during each phase of HSPC culture for red blood cell production in serum-supplemented (SS) and serum-free (SF) conditions. A simultaneous decrease in growth rate, total protein content, cell size, and the percentage of cells in the S/G2 phase of cell cycle, as well as an increase in the percentage of cells with a CD71^-/GpA⁺ surface marker profile, indicates HSPC differentiation into red blood cells. Compared with proliferating HSPCs, differentiating HSPCs showed significantly lower glucose and glutamine consumption rates, lactate and ammonia production rates, and amino acid consumption and production rates in both SS and SF conditions. Furthermore, extracellular acidification was associated with late proliferation phase, suggesting a reduced cellular metabolic rate during the transition from proliferation to differentiation. Under both SS and SF conditions, cells demonstrated a high metabolic rate with a mixed metabolism of both glycolysis and oxidative phosphorylation (OXPHOS) in early and late proliferation, an increased dependence on OXPHOS activity during differentiation, and a shift to glycolytic metabolism only during maturation phase. These changes indicate that cell metabolism may have an important impact on the ability of HSPCs to proliferate and differentiate into red blood cells.

UV-method for the determination of L-Glutamine and Ammonia in cell culture media, foodstuffs and other materialsPrinciple: (glutaminase)(1) L-Glutamine + H₂O → L-glutamate + NH₄⁺ (microbial glutamate dehydrogenase)(2) NH₄⁺ + 2-Oxoglutarate + NADPH → L-glutamate + NADP⁺ + H₂O

Kit size: *50 assays of each (manual) / 500 assays of each (microplate)

*The number of manual tests per kit can be doubled if all volumes are halved.This can be readily accommodated using the MegaQuant^TMWaveSpectrophotometer (D-MQWAVE).

Method: Spectrophotometric at 340 nmReaction time: ~ 10 minDetection limit: 0.54 mg/L (L-glutamine) 0.06 mg/L (ammonia)Application examples: Cell culture media and cultures, dietary supplements, vegetablesand other materials (e.g. biological samples, etc.)Method recognition:Novel method

Advantages

• Very rapid reaction due to use of high activity glutaminase and uninhibited glutamate dehydrogense
• All enzymes supplied as stabilised suspensions
• Only enzymatic kit available
• Very cost effective
• All reagents stable for > 2 years after preparation
• Mega-Calc™ software tool is available from our website for hassle-free raw data processing
• Standard included