Figure 2. The newly designed filter adapter and its applications.

The adapter is placed on the top of the condenser (A). This adapter has a diaphragm (B) and a gap between the filter and frame (C). (D) Bright field and (E) fluorescence of green fluorescent protein (GFP)-labeled embryonic stem (ES) cells in the ICM of a chimeric mouse blastocyst. When the diaphragm is opened, halogen light can pass around the filter and a merged image can be obtained (F). This filter adapter could also be useful in purifying rare cell populations. Typically, fluorescence-activated cell sorting is used for this purpose, but cannot be applied if samples do not contain sufficient cell numbers. We collected spermatogonia from neonatal mouse testes using a CD9 antibody labeled with phycoerythrin. The CD9-positive spermatogonia could be discriminated from other cells and we were able to collect them using a micromanipulator without the need for a mercury vapor lamp. (G) Spermatogonia were detected using a CD9 antibody–phycoerythrin conjugate and positively stained cells (arrows) were drawn into a micropipette using a micromanipulator (H).