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Electrospray ionization mass spectrometry is a powerful tool for identification of biomolecules such as peptides, proteins, oligosaccharides and neurotransmitters. Recent development of the nanospray techniques, applied at ultralow flow-rates, allowed a sensitive analysis of compounds at femto/attomolar level. Here, we present application of a novel nanospray device for the analysis and fragmentation of peptides with high sensitivity on a sector instrument. The lowest applied flow-rate of the mobile phase was maintained at 50 nl/min with a sample load of 90 fmol. Nanospray also provided a complete analysis of 500 nl of the sample for over 10 min, including sequencing of as little as 40 pmol of a substance. Such analysis provides full structural information necessary to identify the molecules.
BACKGROUND AND AIMS: The kisspeptins (KP) are a family of peptide hormones, which in recent years have been shown to play a crucial role in the regulation of the hypothalamic–pituitary–gonadal axis, thus in turn influence fertility and reproduction. One of the fragments of KP-54 termed Kissorphin (KSO) shares amino acid similarities with the biologically active sequence of NPFF therefore it is possible that KSO could exhibit NPFF-like activity (Simonin et al. 2006) without influence on concentration of gonadotropinreleasing hormone (Roseweir et al. 2009, Milton 2012). This is particularly important since the NPFF may participate to the control of the mesocorticolimbic dopamine system activity by counteracting the effect of many psychostimulants (Marco et al. 1995, Cador et al. 2002). Therefore the aim of the present study was to investigate whether a KSO (Tyr-Asn-Trp-Asn-Ser-Phe-NH2) influence the expression of morphine- and ethanol-induced CPP. METHODS: Morphine- and ethanol-induced CPP were induced according to the previously established methods (Kotlinska et al. 2007). RESULTS: Our experiments showed that KSO, given intravenously (iv) at the doses of 1, 3 and 10 nmol/300 µl, inhibited the expression of both morphine and ethanol-induced CPP. KSO gave itself, neither induced place preference nor aversion. CONCLUSIONS: These results suggest that KSO is involved in the expression of morphine and ethanol reward. Moreover, our study supports an anti-opioid character of this peptide.
Temporin A (TA) and a cecropin A-temporin A hybrid peptide (CATA) were synthe­sized and assayed for their hemolytic, anticoagulant, and antifungal properties. CATA retains significant antifungal activity, is less hemolytic than TA, and inhibits blood coagulation. These results recommend further studies of the biological activi­ties of CATA.
A method has been developed for laser desorption/ionization of catecholamines from porous silicon. This methodology is particularly attractive for analysis of small molecules. MALDI TOF mass spectrometry, although a very sensitive technique, uti­lizes matrices that need to be mixed with the sample prior to their analysis. Each ma­trix produces its own background, particularly in the low-molecular mass region. Therefore, detection and identification of molecules below 400 Da can be difficult. Desorption/ionization of samples deposited on porous silicon does not require addi­tion of a matrix, thus, spectra in the low-molecular mass region can be clearly read­able. Here, we describe a method for the analysis of catecholamines. While MALDI TOF is superior for proteomics/peptidomics, desorption/ionization from porous sili­con can extend the operating range of a mass spectrometer for studies on metabo- lomics (small organic molecules and their metabolites, such as chemical neuro­transmitters, prostaglandins, steroids, etc.).
Linear and cyclic hymenistatin I (HS I) analogues with dipeptide segments Ile2 -Pro3 , Pro3 -Pro4 and Val6 -Pro7 replaced by their tetrazole analogues Ile2-Ψ[CN4]-Ala3 , Pro3 -Ψ[CN4]-Ala4 and Val6 -Ψ[CN4]-Ala7 were synthesized by the solid phase peptide synthesis method and cyclized with the TBTU and/or HATU reagent. The peptides were examined for their immunosuppressive activity in the lymphocyte proliferation test (LPT).
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