The oxidation of allylic alcohols is challenging to perform in a chemo‐ as well as stereo‐selective fashion at the expense of molecular oxygen using conventional chemical protocols. Here, we report the identification of a library of flavin‐dependent oxidases including variants of the berberine bridge enzyme (BBE) analogue from Arabidopsis thaliana (AtBBE15) and the 5‐(hydroxymethyl)furfural oxidase (HMFO) and its variants (V465T, V465S, V465T/W466H and V367R/W466F) for the enantioselective oxidation of sec‐allylic alcohols. While primary and benzylic alcohols as well as certain sugars are well known to be transformed by flavin‐dependent oxidases, sec‐allylic alcohols have not been studied yet except in a single report. The model substrates investigated were oxidized enantioselectively in a kinetic resolution with an E‐value of up to >200. For instance HMFO V465S/T oxidized the (S)‐enantiomer of (E)‐oct‐3‐en‐2‐ol (1 a) and (E)‐4‐phenylbut‐3‐en‐2‐ol with E>200 giving the remaining (R)‐alcohol with ee>99% at 50% conversion. The enantioselectivity could be decreased if required by medium engineering by the addition of cosolvents (e. g. dimethyl sulfoxide).
Einfuhrung und Fragestellung Die terminate Strombahn des GefaIsystems der menschtichen Nasenschleimhaut ist morphotogisch hoch differenziert. Ihre feine Struktur aus Arterien, Arterioten, Kapillarsystemen, arteriovenösen Anastomosen, venösen Sinusoiden, Venolen und Venen ermoglichen es der menschlichen Nasenschteimhaut im Zusammenspiel mit den Ge-fäIsphinkteren rasch den Zustand der Blutfullung zu verändern, und so ihren physiplogischen Aufgaben wie Erwärmung und Befeuchtung, nachzukommen. Kontrottiert wird der Füllzustand der terminalen Strombahn einerseits durch die in der Adventitia der Gefage getegenen marktosen vasomotorischen Nervenfasern, andererseits durch die in der Blutbahn zirkulierenden vasoaktiyen Stoffe. Adrenerge Nervenfasern bewirken auf chemischem Wege aipha-Rezeptoren eine Vasokonstriktion. Cholinerge Nervenfasern haben eine vasodilatierende Wirkung. Daf die Vasodilatation nicht ausschlieflich cholinerg vermittelt wird, ist durch ihre weitgehende Atropinresistenz bewiesen (1, 6, 15). Zahlreiche Untersuchungen weisen darauf hin, daf neben den ,,klassischen" Transmittersubstanzen Acetyicholin und Noradrenalin auch anderer Ubertragerstoffe mit vasodilatierender Wirkung aus der Gruppe der Neuropeptide im menschlichen zentralen und peripheren Nervensystem existieren. Bisher konnten mehr als 50 verschiedene Peptide
In about 10% of patients who are operated on for chronic sinusitis, an aspergilloma is found in the affected paranasal sinus. In order to detect possible underlying immune defects, 25 patients with aspergillomas were subjected to an immunological screening program. The data obtained were compared with those of patients with non-mycotic chronic sinusitis and healthy controls. Total lymphocyte counts and immunoglobulin levels were normal in both groups with sinusitis. However, leukocyte subset analyses using membrane fluorescence revealed a significant decrease of CD11+ cells (macrophages, monocytes and natural killer-cells) in both types of sinusitis. Furthermore, a markedly enhanced frequency of CD25+ cells (interleukin 2-receptor-bearing cells), was observed in patients with the aspergillomas. Additionally, peripheral blood lymphocytes in both groups of patients showed a significant reduction in the proliferative response to both T- and B-cell mitogens, with the values for the mitogens ConA and PHA being significantly lower in the aspergilloma patients as compared to those with non-mycotic sinusitis. This lack of lymphocyte stimulation in the aspergilloma group was also manifest in skin tests to recall antigens. These first data suggest that there is an immune deficiency in patients with chronic sinusitis caused by Aspergillus fumigatus. Further studies are needed to clarify if this defect is the cause or the result of the mycotic infection.
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