Surface Replica Technique Research Articles

Use of egg membrane lysins in the preparation of sea urchin egg ghosts

Summary A water-soluble component, extracted from spermatozoa of Strongylocentrotus purpuratus, was used to lyse the eggs of these sea urchins. The egg peripheral membrane system was broken and the cytoplasmic components were extruded through the opening leaving only the egg ghosts. By the use of the preshadowed surface replica technique, the fine structure of the outer surface of purified ghosts was observed in the electron microscope to be an assembly of twisted filaments of about 20 A in thickness, and no regular repeating patterns were found. Since isolated ghosts disintegrated when the vitelline membrane component was removed from the peripheral membrane system by trypsin treatment, either before or after introduction of sperm extract, the surface ultrastructure observed on intact ghosts might be that of the vitelline membrane.

A surface replica technique for the examination of quartz sand grains in the electron microscope

ABSTRACT An improved method for preparing surface replicas of quartz sand grains using water soluble polyvinyl alcohol is described.

A surface replica technique for the examination of quartz sand grains in the electron microscope

ABSTRACT A paragenetic sequence of three authigenic minerals has been photographed in a fine-grained sandstone using the scanning electron microscope (SEM). The instrument used in these studies is the Stereoscan, manufactured by Cambridge Instrument Company. The SEM is superior to the transmission electron microscope for revealing delicate authigenic minerals. The electron micrographs illustrate the value of the SEM in studying micro-features of sedimentary rocks and point out the continuing need for supplementary mineralogical data.

The Surface of Cotton Fibers

The topography of unmoditied cotton fibers has been examined microscopically by means of surface replica techniques. The outstanding characteristic of the surface is a system of roughly parallel ridges and grooves spiraling around the fiber at an acute angle (usually 20 30 ) to its axis. The pattern of the surface is a reflection of the spiral fibrillar structure of the cellulose beneath the primary wall of the fiber. The average height and distance between ridges is approximately 0.5 micron. and many of the ridges are 10 or more microns in length. The surfaces of most native cottons are quite similar, although statistically significant differences in the average distance between ridges were found between certain samples The surface of fibers from unopened bolls is relatively smooth, but assumes the roughness of the typical fiber on drying for the first time. A characteristic surface formation ap peared to be associated with fibers known to have undergone compression. Drastic abrasion largely obliterates the normal appearance of the fiber surface.

The Electron Microscope in the Study of Paints

A brief account is given of the theory of the electron microscope and the special specimen techniques that are employed A method of mounting pigments and a surface replica technique for paints is d...