The Air Turbine Ultracentrifuge, together with some Results upon Ultracentrifuging the Eggs of Fucus serratus

Abstract

1. An air turbine ultracentrifuge suitable for biological work and capable of developing a centrifugal force from 10,000 to 500,000 times gravity has been described. Advantages of the ultracentrifuge are: (1) The temperature does not vary in the centrifuge chamber over 2 or 3 degrees from that of the atmosphere; this is not sufficient to be an important factor in general biological work. (2) The cost of constructing the apparatus is very low in comparison with that of other high speed centrifuges.2. A modification of the air turbine ultracentrifuge in which the turbine rotor drives a second rotor, in this case the centrifuge rotor which spins in a vacuum, has been described. Here the centrifuge chamber is thermally insulated which is an important item in preventing troublesome convection currents from arising in the centrifuged material where such special problems as the rate of molecular sedimentation are being observed. Forces in excess of one million times gravity can easily be obtained by such an apparatus.

Modification of the Developmental Axis by Centrifugation in <i>Pteris vittata</i>

“…It is well known that even if the contents of Equisetum spores are strati fied in any direction by centrifugal force, it cannot modify the original developmental axis of the spore (Mosebach 1943, Nakazawa 1957. Similarly, the fact that the developmental axis is not altered by centrifuging was revealed in many experiments, for example; in Crepidula eggs (Conklin 1917), Fucus serratus eggs (Beams 1937), Urechis eggs (Pease 1939), sea urchin eggs (Motomura 1949), Vaucheria spores (Weber 1959) and in Coccophora and Sargassum eggs (Nakazawa 1961). Concerning these facts, Motomura (1949), Bunning (1957) and Nakazawa (1961) are of the opinion that the determinant of the developmental axis of these materials is concealed in the cortical cyto plasm which is hardly changeable by centrifugation.…”

The Protoplasmic Viscosity of Paramecium

“…The choice of instrument lay between the type designed by Harvey (1933), or that described by Beams (1937). These differ greatly in their optical systems, each having its own particular merits; the type due to Beams is carried on the air-turbine centrifuge, while Harvey's instrument has an electric drive.…”

Centrifuge polarizing microscope. I. Rationale, design and instrument performance

“…In this system, a first‐surface mirror is built into the rotor so that its reflecting surface intersects the rotational axis of the rotor in the plane containing the specimen (Fig. 2 from Beams, 1937). A horizontal microscope views the image of the specimen reflected from the 45° mirror, as though the specimen were aligned with the rotational axis of the turbine, thus keeping the image of the specimen more or less stationary.…”

“… Beam vs. centrifuge microscope (from Beams, 1937). (A) The specimen, placed in a high‐speed air‐driven centrifuge, is viewed with an external, horizontal microscope.…”

“…They found in Ascaris that the fertilized egg stratified by centrifugation could form normal appearing mitotic figures and undergo one to a few cycles of mitoses, but that the ensuing cleavages were absent at 150 000 × g , although not at 5000 × g . Fertilized Fucus eggs appeared to develop normally after centrifuging at 150 000 × g for 30 min (Beams, 1937).…”