DIFFRACTION CONTRAST IMAGING OF EXTRACELLULAR-MATRIX COMPONENTS USINGZERO-LOSS FILTERING

The beta-chitin microfibrils hom the deep-sea hydrothermal vent worm R iftia pachyptila were studied in both mature and fresh tubes experimen tally obtained. The methods used were electron diffraction and electro n diffraction contrast images, in conjunction with an electron-energy filter, operated in the zero-loss mode, In both studied samples, micro fibrils are organized in successive layers, inside which they are para llel. However, the fresh tube is less densely packed and diffraction d ata show that these microfibrils may be in a partially hydrated state. These results indicate that a later step occurs in the compaction of the tube material once it has been extruded. Comparison of filtered an d unfiltered diffraction patterns shows that zero-loss filtering signi ficantly improves both working conditions and quality of diffraction r ecordings. (C) 1997 Academic Press.