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- Haak-Frendscho, M, et al.
(författare)
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Histidine decarboxylase expression in human melanoma.
- 2000
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Ingår i: Journal of Investigative Dermatology. - : Elsevier BV. - 0022-202X .- 1523-1747. ; 115:3, s. 345-52
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Tidskriftsartikel (refereegranskat)abstract
- Histamine has been implicated as one of the mediators involved in regulation of proliferation in both normal and neoplastic tissues. Histidine decarboxylase, the only enzyme that catalyzes the formation of histamine from L-histidine, is an essential regulator of histamine levels. In this study, we investigated the gene and protein expression of histidine decarboxylase in melanoma. Reverse transcriptase polymerase chain reaction and in situ hybridization studies of WM-35, WM-983/B, HT-168, and M1 human melanoma cell lines both resulted in positive signals for histidine decarboxylase messenger RNA. A polyclonal chicken antibody was developed against human histidine decarboxylase and protein expression was confirmed by western blot analysis of the cell lysates, revealing a predominant immunoreactive band at approximately 54 kDa corresponding to monomeric histidine decarboxylase. Protein expression of histidine decarboxylase was also shown by flow cytometric analysis and strong punctate cytoplasmic staining of melanoma cell lines. Moreover, both primary and metastatic human melanoma tissues were brightly stained for histidine decarboxylase. When compared with the very weak or no reactions on cultivated human melanocytes both western blot and immunohistochemical studies showed much stronger histidine decarboxylase expression in melanoma cells. These findings suggest that expression of histidine decarboxylase is elevated in human melanoma.
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| 2. |
- Horváth, E., et al.
(författare)
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Investigation of mandelic acid bonding on Pirkle type chromatographic stationary phases by Raman spectroscopy
- 2000
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Ingår i: Journal of Chromatography A. - 0021-9673 .- 1873-3778. ; 893:1, s. 37-46
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Tidskriftsartikel (refereegranskat)abstract
- The bonding of mandelic acid enantiomers has been studied on benzene-leucine, dinitrobenzene-leucine and dinitrobenzene-phenylalanine type chiral stationary phases connected to zeolite A supports. The π-donor, π-acceptor and H-bonding interactions responsible for diastereomer pair formations can be studied under quasi in situ chromatographic conditions by Fourier transform Raman and surface enhanced Raman spectroscopic techniques. Structural differences between diastereomer pairs result in observable spectral differences at a phase load of approx. 50%. It was shown that the decreasing π-acceptor character of the phase is associated with its increasing capability of H-bond formation. Correlating spectral data to chromatographic results it can be concluded that, in addition to H-bonding as well as to π-donor-π-acceptor interactions, steric hindrances due to bulky moieties of either the stationary phase or the analyte molecules are of importance in successful separations.
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| 3. |
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| 4. |
- Horvath, I. S., et al.
(författare)
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Selection of anion exchangers for detoxification of dilute-acid hydrolysates from spruce
- 2004
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Ingår i: Applied Biochemistry and Biotechnology. - 0273-2289 .- 1559-0291. ; 113, s. 525-538
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Tidskriftsartikel (refereegranskat)abstract
- Six anion-exchange resins with different properties were compared with respect to detoxification of a dilute-acid hydrolysate of spruce prior to ethanolic fermentation with Saccharomyces cerevisiae. The six resins encompassed strong and weak functional groups as well as styrene-, phenol-, and acrylic-based matrices. In an analytical experimental series, fractions from columns packed with the different resins were analyzed regarding pH, glucose, furfural, hydroxymethylfurfural, phenolic compounds, levulinic acid, acetic acid, formic acid, and sulfate. An initial adsorption of glucose occurred in the strong alkaline environment and led to glucose accumulation at a later stage. Acetic and levulinic acid passed through the column before formic acid, whereas sulfate had the strongest affinity. In a preparative experimental series, one fraction from each of six columns packed with the different resins was collected for assay of the fermentability and analysis of glucose, mannose, and fermentation inhibitors. The fractions collected from strong anion-exchange resins with styrene-based matrices displayed the best fermentability: a sevenfold enhancement of ethanol productivity compared with untreated hydrolysate. Fractions from a strong anion exchanger with acrylic-based matrix and a weak exchanger with phenol-based resin displayed an intermediate improvement in fermentability, a four- to fivefold increase in ethanol productivity. The fractions from two weak exchangers with styrene- and acrylic-based matrices displayed a twofold increase in ethanol productivity. Phenolic compounds were more efficiently removed by resins with styrene- and phenol-based matrices than by resins with acrylic-based matrices.
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