Centrifuge polarizing microscope. II. Sample biological applications

Abstract

SummaryThe rationale, design and general performance of the CPM (centrifuge polarizing microscope) were described in Part I of this study (Inoue  et al. J. Microsc. 201 (2001) 341±356. In this second part, we describe observations on several biological samples that we have explored over the past two years using the CPM.As described in the first part of the study, although the CPM was basically designed as a high-extinction centrifuge polarizing microscope, it also allows observations of the specimen exposed to high centrifugal fields up to 10 500  g (earth's gravitational acceleration) in fluorescence (532-nm excitation) and in DIC (differential interference or Nomarski contrast).

Directly observed reversible shape changes and hemoglobin stratification during centrifugation of human and Amphiuma red blood cells

“…Contrast of the specimen placed in the chambers, whose windows are designed to suffer only low degrees of stress birefringence, can be generated in bright field, in polarization optics with a sensitivity exceeding 1 nm in retardation, in differential interference contrast (Nomarski contrast), or in f luorescence excited by the 532-nm neodymium-yttrium͞ aluminum garnet laser illumination (32). Human red cells were generally observed with the compensator rotated sufficiently away from extinction, in other words, essentially as bright-field images, whereas the Amphiuma cells were observed either in bright field (Fig.…”

Live-cell imaging under centrifugation characterized the cellular force for nuclear centration in theCaenorhabditis elegansembryo

“…The centrifuge polarizing microscope (CPM) invented by Inoué and colleagues is capable of imaging under a rotational speed that generates up to ~10,000 ×g, the fastest to date, to the best of our knowledge 19,20 . The CPM has been used to apply forces to various biological samples [21][22][23] . In this study, by applying centrifugal forces using the CPM, we measured the cellular forces and frictional coefficient for nuclear centration in C. elegans embryos.…”