Tryptophan (Trp) and its metabolites, especially indole-3-acetic acid (IAA), are considered to be potential precursors of 2-aminoacetophenone (AAP), an aroma compound that causes an "untypical aging off-flavor" (UTA) in Vitis vinifera wines. In this study, RP-HPLC with fluorescence detection was used for the qualitative and quantitative analysis of Trp and Trp metabolites in grape musts and wines to which different viticultural measures had been applied (time of harvest, soil treatment, leaf plucking, vine prune). An alkaline hydrolysis was developed to release bound IAA and Trp. A sensitive and selective determination of different Trp metabolites was achieved after solid phase extraction using a strong anion exchange material. In the examined grape musts, more than 95% of the total IAA was bound either as ester conjugate or as amide conjugate. Free IAA and other Trp metabolites were below the detection limit (<3 microg/L) or could be determined only in traces. Their amounts increased significantly during fermentation, whereas the amount of Trp decreased. It could be shown that the different viticultural measures applied (except the vine prune) as well as the climatic conditions of the vintage exhibited significant influences on the amounts of Trp and Trp metabolites in grape musts or wines.
Zn dem ersten eucht, wie m e Obigem erbellt, auch Hr. R a y m a n n zu gelangen; dennoch werde ich meine schon begonnenen Untereuchnngen iiber die Darstelluog der beiden Kbrper forteeteen, urn so mehr als die bis jetzt erhaltenrn Thataachen ziir Aanahme innerer Condensation in der Metareihe zu fiihren schoinen.St. P e t e r s b u r g , Berg-Institat. H. Kohler mdA. M i c h a e l i e : Ueber Phenylphorphin nnd Phorphobenrtol (Diphorphenyl). Der Eine von uns hat friiher 1) gezeigt, dass aurch Einwirkung von Alkohol aaf jodwweratoffeaures Phosphenyljodiir C, H, P J,, H J Phenylphosphin entsteht, gemiim der Gleichung: 3 C, H, P J, I H J + 9 C g H, O H = C, H5 P Ha + 2 C, H, P O (0 H), + 3 H 2 0 + 9 c2 H, J. Bei weiterem Studium d i e e r Reaction haben wir gefunden , daae die Einwirknog nur earn Thai1 nach dieser Gleichung verl&oft, und dnae eI0 groreer Theil dee Jodiirs nach der Oleichung zersetzt w i d . Die BO gebildete phosphenylige SHure zerftillt aber beim Erhitxen miter in Phosphenyleeiure und Phenylphosghin, wie An anoff') end der Eine von nna gezeigt haben. Da nundie Denitellung den jodwwemtoffeauren Phenylphosphina immer etwae umetlindlich iat, haben wir veraucht, das Pheoylphosphin nur nach lottterer Reaction darzuetellea. M i c h a e l i e und A n a n o f f baben ewar friiher gefunden, daaa durch Erhitzen 0011 phoephenyliger S u r e nur eehr wenig Phenglphoephin enteteht, d a dieeelben damals aber nur mit wenlgen Grammen arbeiteten, so echien es une nicht unwichbg die Reaction mit griimeren Mengen zu wiederholen. Wir wollen gleich bier bemerken, d w wir diese Methode als eebr hrauchbr gefunden haben, M) dime ea jetzt keine Schwierigkeit mehr macht, Phenylphosphin aas Phospheoylchlorid darzustellen. C, H,PJ, HJ + 3CaK6OH = C s H 5 PO1 H, + H a 0 + 3C2H, J I) Ann. Cham. 181, 841. *) Dieae Berichte VII, 1888.
CD44 is an integral cell-surface glycoprotein. Overexpression of the CD44 standard (CD44st) and its variants (CD44v) has been implicated in transformation and progression of many cancer types. Here, we investigated expression of CD44st, CD44v3-7, CD44v7/8, and v10 in five human pancreatic tumor cell lines and normal human pancreatic duct cells transfected with the SV40 large T antigen. CD44st and its variant proteins were quantified using immunocytochemistry and flow cytometry. CD44v7 was expressed at low levels, whereas CD44st, CD44v3, CD44 v4, CD44v, and CD44v6 were expressed at moderate levels in all pancreatic tumor cell lines. In contrast, CD44v7/8 and CD44v10 were expressed at very low levels in two out of the five pancreatic tumor cell lines. Overall, staining of CD44st and CD44 variants was significantly weaker compared to another surface molecule, ICAM-1, reported to be overexpressed in pancreatic cancer cells. Furthermore, the SV40 large T transfected duct cells showed only a weak staining for CD44st, CD44v5, and CD44v6. To determine a possible mechanism for the regulation of surface expression of CD44st, v5 and v6, we incubated Panc-1 cells with bFGF, TGF-β1, EGF, TNFα, and IFNγ. Only IFNγ affected the CD44 expression by down-regulation of CD44v6. The constitutive expression of CD44 variants seems to be associated with the malignant state of invasive carcinoma. Teratogenesis Carcinog. Mutagen. 21:97-106, 2001.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.