dithranol-as-matrix-for-matrix-assisted-laser-desorptionionization

Dithranol as a Matrix for Matrix Assisted Laser Desorption/Ionization Imaging on a Fourier Transform Ion Cyclotron Resonance Mass Spectrometer

Mass spectrometry imaging (MSI) determines the spatial localization and distribution patterns of compounds on the surface of a tissue section, mainly ...

University of Victoria

Asukamycin, a manumycin-type metabolite, was isolated by a rapid and easily scalable purification scheme. Thus far, studies on the biological activity of asukamycin have been limited to its role as an antibacterial and antifungal agent. By using five different tumor cell lines we demonstrate antineoplastic activity of asukamycin. It inhibited cell growth at concentrations similar to other members of the manumycin family (IC50 1-5 microM). Cytotoxicity of asukamycin was accompanied by activation of caspases 8 and 3 and was diminished by SB 202190, a specific p38 mitogen-activated protein kinase (MAPK) inhibitor. These data, in combination with earlier observations showing its low in vivo toxicity, indicate that further studies on the potential antitumor activity of asukamycin are warranted.

Antitumor activity of asukamycin, a secondary metabolite from the actinomycete bacterium Streptomyces nodosus subspecies asukaensis.

Melatonin and serotonin have previously been described in mature wine grapes and finished wines, but the metabolism of these signalling molecules in the development of wine grapes has not previously been investigated. We harvested wine grapes at different stages of development from lag phase through véraison from eight different commercial vineyards representing a diversity of growing conditions, management practices, merlot varietals and localized ecosystems to determine whether different patterns in melatonin and serotonin can be found in wine grapes during seed development and berry maturation. Melatonin was detected in 45% of the fully developed purple, postvéraison grapes but only found in 23% of prelag phase samples. However, the actual concentration of melatonin was highest in wine grapes harvested at the early stage of véraison when the seed is developing. Serotonin was not detected in any of the prelag phase grapes but was consistently detected in 30-35% of grapes harvested during the véraison transition at consistent levels of about 8-10 mug/g. Interestingly, the nitrogen storage compound gamma-aminobutyric acid was also found at about 115 mug/g in 77% of early stage green grapes and declined in both prevalence and concentration with ripening. Together, these data are indicative of a potential role for these molecules in the development and maturation of wine grapes.

Changes in the levels of indoleamine phytochemicals during véraison and ripening of wine grapes.

To fill the unmet need for improved matrixes for matrix-assisted laser desorption ionization (MALDI) tissue imaging of small molecules, dithranol (DT)--a matrix mainly used for the analysis of synthetic polymers--was evaluated for detection of lipids in rat liver and bovine calf lens, using MALDI Fourier transform ion cyclotron resonance mass spectrometry (FTICR MS). The use of DT resulted in better detection of endogenous lipids than did two other commonly used matrixes, α-cyano-4-hydroxycinnamic acid (CHCA) and 2,5-dihydroxybenzoic acid (DHB), with >70 lipid entities (including phosphatidylcholines, phosphatidylethanolamines, sphingomyelins, phosphatidylserines, phosphatidylglycerol, phosphatidic acids, ceramide phosphates, sterol lipids, acyl carnitines, and glycerides) being detected in rat liver and bovine lens tissue sections, using positive-ion detection. Using saturated DT in chloroform/methanol (2:1, v/v), with 1% formic acid in the final mixture, 57 lipid entities were successfully imaged from bovine calf lens, with clear and distinct distribution patterns. In a section across the lens equatorial plane, all compounds showed concentric distributions around the lens nucleus and most showed specific abundance changes, which correlated with lens fiber cell age. As a novel finding, palmitoylcarnitine and oleoylcarnitine were found uniquely localized to the younger lens fiber cell cortex region. This work demonstrates the potential of DT as a new matrix for tissue imaging by MALDI-FTICR MS.

Article	Year
Antitumor activity of asukamycin, a secondary metabolite from the actinomycete bacterium Streptomyces nodosus subspecies asukaensis. International journal of molecular medicine\| PubMed ID: 19787206	2009
Changes in the levels of indoleamine phytochemicals during véraison and ripening of wine grapes. Journal of pineal research\| PubMed ID: 20536685	2010
Dithranol as a MALDI matrix for tissue imaging of lipids by Fourier transform ion cyclotron resonance mass spectrometry. Analytical chemistry\| PubMed ID: 22931516	2012

Cuong H. Le

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