A new versatile compression chamber for examination of living microorganisms

Abstract

A new type of compression chamber for microscopic studies of living microorganisms is described. This broadly applicable instrument allows controlled slowing down, turning and compression of vagile organisms. It has been developed for use with different types of microscopes, especially the modern inverted versions. Due to the extremely flat design, illumination according to the Köhler principles is guaranteed. Therefore, all modern procedures such as bright-, darkfield, phase-contrast, differential interference contrast, polarized and fluorescent microscopy can be carried out. Once focused, parfocal objective lenses (even oil immersion high power objectives) can be interchanged without refocusing. The chamber is composed of three basic elements: (1) baseplate, with cylindrical head-piece, (2) compression ring for vertical adjustment, (3) rotor, non-threaded and gliding on viscous silicon. An upper and a lower circular coverslip is permanently glued to the rotor and baseplate respectively. Preparation and interchange of the specimens are rapidly done by lifting and subsequent insertion of the non-threaded rotor. Thus, the new chamber is an almost non-evaporating closed system and the organisms to be studied are preserved alive for many hours. Except when high power magnifications are used, the principles, on which the compression chamber is based, allow various modifications in outfitting and design, such as transformation into a continuous flow system for fresh- or seawater, or exchange of media at choice. The chamber and its function is compared with similar instruments, such as the rotocompressor and the Spoon microcompressor.