Showing papers by "Andreas Herrmann published in 1997"
TL;DR: The results suggest that the presence of specific sphingolipids is sufficient to mediate lytic activity of eiseniapore, and this action contributes to the understanding of earthworm immune responses.
69 citations
TL;DR: It is concluded that 1) the GPI-HA-mediated hemifusion intermediate is meta-stable and 2) expansion of an aqueous fusion pore requires the transmembrane and/or cytoplasmic domain of HA.
49 citations
TL;DR: The results support recent hypotheses that the fusion-competent conformation is an intermediate of the fusionThe fusion-inactivated structure of HA is found to be in its early phase reversible as found for A/Japan.
42 citations
TL;DR: Hohere Fullerene stehen zwar noch nicht in groseren Mengen zur Verfugung, doch hat sich the Situation ahnlich wie bei C60 seit den Anfangstagen der Fullerenchemie stetig verbessert as discussed by the authors.
Abstract: Hohere Fullerene stehen zwar noch nicht in groseren Mengen zur Verfugung, doch hat sich die Situation ahnlich wie bei C60 seit den Anfangstagen der Fullerenchemie stetig verbessert. Viele der loslichen groseren Kohlenstoffkafige sind mittlerweile in reiner Form oder als Isomerengemische auch kommerziell erhaltlich. Insbesondere C70 kann heute im praparativen Masstab ohne aufwendige hochleistungsflussigkeitschromatographische Trennung ausgehend von Fullerenrus rein gewonnen werden, wodurch die Chemie dieses hoheren Fullerens einen starken Auftrieb erfahren hat. So gelang im Verlauf der letzten Jahre eine Vielzahl von Funktionalisierungen mit C70, und selbst von den groseren und komplexeren Kohlenstoffballen C76, C84 und neuerdings auch C78 wurden Derivate rein isoliert und charakterisiert. Anhand der so gewonnenen Daten lassen sich erste allgemeine Gesetzmasigkeiten zur Reaktivitat und Selektivitat dieser weniger symmetrisch als C60 gebauten Fullerene erkennen. Wichtige Informationen liefern insbesondere Mehrfachadditionen an hohere Fullerene; sie verlaufen mit einer erstaunlichen Selektivitat, die die bei C60 gefundene ubertrifft. Ein besonders reizvolles Thema ist die Chiralitat einiger dieser Kohlenstoffallotrope sowie die zahlreicher Derivate. Zwar beschrankt sich die Chiralitat von Fullerenaddukten nicht auf die hoheren Fullerene, aber sie wurde hauptsachlich im Zusammenhang mit deren Chemie erforscht und kann auf unterschiedliche strukturelle Merkmale zuruckgefuhrt werden. Ein kurzlich vorgeschlagenes System ermoglicht anhand eines einzigen Deskriptors eine einfache Spezifizierung der Konfiguration von chiralen Fullerenen und Fullerenderivaten einschlieslich hochverzweigter Kohlenstoffgeruste mit einer Vielzahl moglicher stereogener Zentren.
27 citations
TL;DR: Evidence is given that the intracellular pH affects the active transport of aminophospholipids but not the extracellular pH, and constituents of the red blood cell cytoplasm do not mediate the influence of pH on the ATP-dependent inward movement ofAminoph phospholipid movement.
21 citations
TL;DR: The kinetics of incorporation of the spin-labeled phosphatidylcholine (PC) analog 1-palmitoyl-2-(4-doxylpentanoyl)-sn-glycero-3-phosphocholine (SL-PC) and of its accessibility to chemical reduction and to back-exchange at room temperature are studied by means of stopped-flow electron paramagnetic resonance (EPR) spectroscopy.
19 citations
TL;DR: Using principles of metabolic control analysis, the role of the various active and passive processes in determining the asymmetric distribution of lipids under in vivo conditions is quantified and explained in quantitative terms.
18 citations
TL;DR: In this paper, three possible structures were finally proposed for a C2-symmetrical tris-adduct of======C2v-C78, and two structures for a======C3-smoothed symmetric trisadrithm of======D3-c78.
Abstract: Multiple cyclopropanation of an isomeric mixture of
C2v- and D3-C78
(ca. 3∶1) with diethyl 2-bromomalonate yielded two
C1-symmetrical bis-adducts, one of which was
isolated without HPLC, and at least eight isomeric tris-adducts. Most of
the adducts were isolated in pure state by HPLC and characterised by
UV–VIS, 1H and 13C NMR spectroscopy, as well
as by mass spectrometry. In the case of the tris-adducts, three isomers
displayed a higher symmetry than C1 and could
therefore be unambiguously assigned to the C78 isomer from
which they arise. Three possible structures were finally proposed for a
C2-symmetrical tris-adduct of
C2v-C78, and two structures for a
C3-symmetrical tris-adduct of
D3-C78. Based on the comparison of the
spectra obtained for the C2-symmetrical tris-adduct
with those of the bis-adducts, three possible structures were proposed
for one of the C1-symmetrical bis-adducts, being the
direct precursor of the corresponding tris-adduct. The compounds
described in this work represent the first adducts
of C2v- and
D3-C78 isolated and characterised
in a pure state.
14 citations
TL;DR: The transbilayer movement and distribution of spin-labelled phospholipid analogues were studied in the plasma membrane of ram sperm cells isolated from functionally different regions of the epididymis (caput, cauda) and from the ejaculate, suggesting an asymmetric steady state transbilayers distribution ofospholipids.
Abstract: The transbilayer movement and distribution of spin-labelled phospholipid analogues were studied in the plasma membrane of ram sperm cells isolated from functionally different regions of the epididymis (caput, cauda) and from the ejaculate. As already shown for ejaculated cells, (i) a rapid movement of aminophospholipid analogues phosphatidylserine and phosphatidylethanolamine from the exoplasmic to the cytoplasmic leaflet, and (ii) a slow transbilayer movement of phosphatidylcholine were observed in the plasma membrane of maturating ram sperm cells. This suggests an asymmetric steady state transbilayer distribution of phospholipids, with a preferential enrichment of aminophospholipids on the cytoplasmic leaflet of those cells. The fast inward redistribution of the aminophospholipid analogues is consistent with the presence of an aminophospholipid translocase activity in all three sperm cell preparations. The translocase activity was enhanced slightly during the epididymal transit of spermatozoa. However, compared with epididymal sperm cells, a marked increase in the aminophospholipid translocase activity and a more pronounced phospholipid asymmetry for phosphatidylethanolamine was established for ejaculated spermatozoa. The physiological relevance of the rapid removal of aminophospholipids from the exoplasmic leaflet of the plasma membrane of ram sperm cells is discussed. The quality of sperm cell fractions was characterized by the cell morphology, membrane integrity and the cellular ATP concentration.
8 citations
TL;DR: Findings show that the influenza virus hemagglutinin (HA) is a suitable vehicle to target foreign proteins with therapeutical potential into the cell membrane and could potentially be used to block the abnormal signals generated by particular proteins in the cell membranes that lead to cell transformation.
3 citations