A NEW TOOL FOR THE OBSERVATION OF EMBRYOS AND OTHER LARGE SPECIMENS -CONFOCAL THETA-FLUORESCENCE MICROSCOPY

A theta microscope for three objective lenses was designed and built a t the European Molecular Biology Laboratory (EMBL). It was used to eva luate the principles of confocal theta fluorescence microscopy and to prove its ability to handle biological specimens, A resolution improve ment over confocal fluorescence microscopy has been predicted due to a detection at an angle to the illumination axis, This is verified usin g fluorescent beads and a fluorophore-coated capillary. The suitabilit y of theta microscopy for the observation of biological specimens is v erified by observing a FITC-labelled mouse embryo, In addition, the de sign of a theta microscope and the handling of biological material are explained in detail.