Premium
Isolation and Partial Characterization of Surface Membranes From Leishmania Donovani Promastigotes *
Author(s) -
DWYER DENNIS M.
Publication year - 1980
Publication title -
the journal of protozoology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.067
H-Index - 77
eISSN - 1550-7408
pISSN - 0022-3921
DOI - 10.1111/j.1550-7408.1980.tb04676.x
Subject(s) - membrane , differential centrifugation , density gradient , chemistry , chromatography , electron microscope , cytoplasm , leishmania donovani , biophysics , biochemistry , leishmania , biology , parasite hosting , physics , quantum mechanics , world wide web , computer science , optics
Cell surface pellicular membranes (PM) were isolated from promastigote forms of Leishmania donovani by differential and discontinuous sucrose gradient centrifugation procedures. the PM had a density equivalent of ∼ 1.19 g/cm 3 . As ascertained by electron microscopy, longitudinal parallel arrays of subpellicular microtubules (MT) remained attached to the isolated PM inner lamina, and this feature was used to assess membrane fraction purity. Gradient fractions having ∼ 95% of all membranes combined with MT were obtained routinely. the attached MT imparted a structural asymmetry to the PM permitting uniequivocal identification of the membrane external and cytoplasmic surfaces. the supramolecular structure of attached MT was evident in negatively stained PM. In ultrathin sections, PM had a mean width of ∼ 7.2 nm and attached MT a diameter of ∼ 29 nm. the MT were apparently cross‐bridged both to each other and to the PM via a flocculent filamentoid nexus. As determined by sodium dodecylsulfate‐polyacrylamide gel electrophoresis, isolated PM contained ∼ 40 peptide bands ranging in apparent molecular weight from ≤ 1.2 × 10 4 to ≥ 2.2 × 10 5 daltons. of these, 19 were stained with periodic acid‐Schiffs’ reagent suggesting that most PM carbohydrate constituents were present as glycopeptides. A presumpative glycolipid/polysaccharide PM constituent was also identified in such gels.