M. De Mets

Low molecular weight protein (γ-crystallin) in the lens of birds

Abstract A method is described for the isolation of low molecular weight protein (γ-crystallin) from the lens of birds, based on a combination of salting-out and gel filtration. The isolated protein appears as a single component after gel filtration, ultracentrifugation and immuno-electrophoretic analysis. Specific antiserum to γ-crystallin of two birds was prepared and the first results of the immunological cross-reactivity with the γ-crystallin of other vertebrates are reported.

Use of the Scanning Electron Microscope for Investigating Pollen Grains isolated from Honey Samples

SummaryExamination of pollen grains with an optical microscope yields imperfect images, owing to the highly refractive properties and opaque character of the grains, and to the very restricted depth of focus. A preliminary report is given on the use of the scanning electron microscope for pollen analysis of honey. The images provide an extremely good representation of the surface texture of the pollen grains, and are characterized by a considerable depth of focus.

Improved cathodoluminescence detection system.

Cathodoluminescence collection could be improved by using an ellipsoid mirror with a photomultiplier installed directly in the second focus of the mirror. No losses of light due to the light guide coupling can occur in this way.

Cathodoluminescence and stationary phase distribution: Experiments with diatomite supports

Abstract The stationary phase distribution on diatomite supports was controlled using the cathodoluminescence mode of operation of the scanning electron microscope. Benzylbiphenyl was loaded on Gas-Chrom P and Chromosorb P. Phase accumulation was present, independent of the loading technique used, and conditioning did not change this pattern.

Studies on embedding materials. I. Polydiallylphthalate (PDAP), a new embedding medium for biological tissues.

Polydiallylphthalate (PDAP) has been studied as a new embedding medium for biological tissues. The composition of the monomer mixture is: 10 ml diallylphthalate, 2 ml dibutylphthalate (flexibilizer), and 0.4–0.6 g benzoylperoxide (initiator). This mixture has an acceptable viscosity and infiltrates quite easily into the specimen. It is compatible with dehydrating liquids such as ethanol, acetone, and propylene oxide and can be stored for several weeks at 4°C. Polymerization is achieved in 2–3 days at 60°C, and longer heating times do not change the mechanical properties of the final product. This material has excellent cutting properties, and thin sections have been stained with KMnO 4 , uranyl acetate and lead citrate. Also sections of large size can be obtained and collected on grids without supporting membrane.

Scanning electron micrographs of small holes

The bottom of small and deep holes can be examined more clearly with the scanning electron microscope by using gun high tension values between 10 and 3 kv.