Wynik wyszukiwania w bazie Polska Bibliografia Lekarska GBL

Zapytanie: KORYCKA-MACHAŁA
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Tytuł oryginału: Lipidy ściany komórkowej rodzaju Mycobacterium.
Tytuł angielski: Mycobacterial cell wall lipids.
Autorzy: Rumijowska-Galewicz Anna, Korycka-Machała Małgorzata, Sedlaczek Leon
Źródło: Post. Mikrobiol. 2002: 41 (3) s.235-258, il., tab., bibliogr. 100 poz., sum.
Sygnatura GBL: 304,786

Hasła klasyfikacyjne GBL:
  • mikrobiologia

    Streszczenie angielskie: Mycobacteria are surrounded by a cell wall unique structural and functional features which result from the chemical compositum of the variety of lipids and related compounds. The outermost cell wall layer is composed mainly of easily extractable species-and type-specific complex lipids. These include glycolipids, sulpholipids (SL), glycopeptidolipids (GPL), lipooligosaccharides (LOS), phenolic glycolipids (PGL), acylated trehaloses (trehalose-6,6'-dimycolate and other trehalose esters), waxes (phtiocerol dimycocerostases PDIM), lipoarabinomannan (LAM), phospholipids, triglicerides and others. The polarity of these lipids ranges from non-polar PDIM to highly polar GPL and LOS. Most of these lipids are characterized by unsual long-chain saturated and unsaturated fatty acids with numerous methyl branches, i.e., mycocerosoic, phtioceranic, mycolipenic and phlei acids, whose chemical structure differs markedly from those which form the plasma membrane. Some complex lipids of the outermost cell wall layer are bilogically active phenolic glycolipids, polar glycopeptidolipids and lipooligosaccharides are proven surface antigens. Mycolic acids, which are the most prominent component of the mycobacterial cell wall, from its lipidic interior. They are ŕ-branched-á-hydroxy fatty acids in which the main chain (meromycolate) contains 50 to 60 carbon atoms chracterized by double bonds, keto groups, methoxy groups and/or cyclopropyl rings. The ŕ=branch chain has been shown to be a saturated hydrocarbon containing 22 to 26 carbon atoms. Mycolic acids occuree as a close-packed quasi-crystalline layer perpendicular to the peptidoglycan layer.

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    Tytuł oryginału: Fizyczna organizacja składników ściany komórkowej mikrobakterii i jej przepuszczalność dla związków chemicznych.
    Tytuł angielski: Physical organization and the permeability of the mycobacterial cell wall.
    Autorzy: Korycka-Machała Małgorzata, Rumijowska-Galewicz Anna, Sedlaczek Leon
    Źródło: Post. Mikrobiol. 2002: 41 (3) s.259-276, il., bibliogr. 59 poz., sum.
    Sygnatura GBL: 304,786

    Hasła klasyfikacyjne GBL:
  • mikrobiologia

    Streszczenie angielskie: The very numerous and varied of the mycobacterial cell wall lipids occur as an unique, asymmetric bilayer. The outer leaflet consists of easily extractable species- and type-specific complex lipids, the polar head groups of which are exposed on the cell surface, whereas the lipidic components interact with hydrocarbon chains of the underlying mycolic acids. Mycolic acids form the inner leaflet of the bilayer, either alone (model of arrangement of the cell wall lipids analogous to structure of a normal biological membrane) or intercalated with intermediate-lenght (C28-34) fatty acid hydrocarbon chains of complex lipids (intercalation model). The branched nature of mycolic acids, with a longer and shorter hydrocarbon chain such intercalation structurally plausible. Biophysical studies including X-ray diffraction analysis of the purified cell wall revealed, that the hydrocarbon chains of mycolic acids are packed side by side, perpendicular to the peptidoglycan layer, and that the mycolic acid-containing inner leaflet is covered by an outer leaflet composed of extractable lipids. The direct consequence of this arrangement is the existence of a fluidity gradient across the bilayer. Differential scanning calorimetric (DSC) and electron spin resonance studies confirm that the deepest part of mycolic acids layer forms a region of extremely low fluidity, resonsible for the permeability barrier to hydrophilic and lipophilic solutes. Small hydrophilic molecules traverse the cell wall through porin channels, but the influx of these agents is extremely slow...

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