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Electron Multiplying Charge-Coupled Devices (EMCCDs)
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.
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Microtubule EB3 in HeLa Cells
 Objective: UPlanSApo 100x oil/1.40 |
Exposure: 250 ms |
| Microscope: Olympus DSU/IX81 |
Gain: 3 |
| Camera: Hamamatsu ImagEM |
Interval: 500 ms |
Microtubules transport vesicles, organelles, and other molecules throughout the cell. Distribution is regulated by motor proteins that ferry, for instance, secretory vesicles for export from the Golgi apparatus to the plasma membrane. Mitochondria are transported back and forth through the cytoplasm by microtubules, while nerve cells use them to translocate vesicles containing neurotransmitters along their axon tips. Motor proteins "burn" adenosine triphosphate (ATP) to fuel the transformation and travel along the microtubules. By altering their three-dimensional conformation, motor proteins move along the microtubule filament by releasing one portion of the filament and gripping another site farther along the tubule. 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.