The fixation of nuclei in glutaraldehyde.

The production of an artifactual network in the nuclear sap of the salivary glands of Drosophila has been investigated. Mechanical stress to the cells, 3% glutaraldehyde containing more than 4 mM calcium, tannins, or cacodylate buffer or whose temperature is above 10 degrees C all enhance this artifactual effect. Over the range pH 6.65-7.4 there is no significant effect of pH. The inclusion of sucrose, and adenine nucleotides or other 'chelating' agents in the fixative reduces the effect, especially at low temperature (6-10 degrees C). These influences are additive and can abolish the artifactual effect. So too can 8% glutaraldehyde, but this is irrespective of temperature.