The structure of chromatophores from purple photosynthetic bacteria fused with lipid‐impregnated collodion films determined by near‐field scanning optical microscopy

FEBS Letters

White, Jeffrey O²  Shinkarev, Vladimir P¹  Wraight, Colin A¹  Brunner, Robert² 

[1] Department of Plant Biology, University of Illinois at Urbana-Champaign, 190 ERML, 1201 W. Gregory Drive, Urbana, IL 61801, USA;Frederick Seitz Materials Research Laboratory, University of Illinois at Urbana-Champaign Urbana, IL, USA

关键词: Near-field scanning optical microscopy;    Chromatophore;    Membrane fusion;    Sulforhodamine B;    Rhodamine 6G;    Rhodobacter sphaeroides;    HEPES;    4-(2-hydroxyethyl)-1-piperazine-ethanesulfonic acid;    NSOM;    near-field scanning optical microscopy;   

DOI  :  10.1016/S0014-5793(99)00630-4

学科分类：生物化学/生物物理

来源: John Wiley & Sons Ltd.

【 摘 要 】

Lipid-impregnated collodion (nitrocellulose) films have been frequently used as a fusion substrate in the measurement and analysis of electrogenic activity in biological membranes and proteoliposomes. While the method of fusion of biological membranes or proteoliposomes with such films has found a wide application, little is known about the structures formed after the fusion. Yet, knowledge of this structure is important for the interpretation of the measured electric potential. To characterize structures formed after fusion of membrane vesicles (chromatophores) from the purple bacterium Rhodobacter sphaeroides with lipid-impregnated collodion films, we used near-field scanning optical microscopy. It is shown here that structures formed from chromatophores on the collodion film can be distinguished from the lipid-impregnated background by measuring the fluorescence originating either from endogenous fluorophores of the chromatophores or from fluorescent dyes trapped inside the chromatophores. The structures formed after fusion of chromatophores to the collodion film look like isolated (or sometimes aggregated, depending on the conditions) blisters, with diameters ranging from 0.3 to 10 μm (average ≈1 μm) and heights from 0.01 to 1 μm (average ≈0.03 μm). These large sizes indicate that the blisters are formed by the fusion of many chromatophores. Results with dyes trapped inside chromatophores reveal that chromatophores fused with lipid-impregnated films retain a distinct internal water phase.

【 授权许可】

Unknown