By incorporating on-chip multiplication gain, the electron multiplying CCD achieves, in an all solid-state sensor, the single-photon detection sensitivity typical of intensified or electron-bombarded CCDs at much lower cost and without compromising the quantum efficiency and resolution characteristics of the conventional CCD structure.
Objective: UPlanSApo 100x oil/1.40 | Exposure: 250 ms |
Microscope: Olympus DSU/IX81 | Gain: 3 |
Camera: Hamamatsu ImagEM | Interval: 500 ms |
Abundant globular cytoplasmic proteins, known as tubulin, are the subunits that comprise microtubules. alpha-tubulin and beta-tubulin are closely related but slightly different globular proteins that form heterodimers, which subsequently bind tightly together to form the basic subunit of microtubules. This structure has the useful property of exhibiting a distinct polarity that arises from the organization of tubulin proteins. In effect, all tubulin homodimers point in the same direction to form 13 parallel protofilaments with only alpha-tubulin proteins exposed on one end and beta-tubulin capping the other. The digital video above illustrates the tracking of microtubule +TIPs (plus end tracking proteins) in human cervical carcinoma (HeLa line) epithelial cells labeled with a chimera of EB3 fused to mEGFP.