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.
Two of the Rab family of proteins involved in vesicle trafficking were targeted in a specimen of pig kidney cells. Rab5a was tagged with the green fluorescent protein mEmerald and Rab4a was fluorescently labeled with mCherry. The Rab5a protein is a marker of early endosomes, while Rab4a is a marker of recycling endosomes. In addition to these two endosomal types, cells also contain a third form of endosome known as the late endosome. Markers of late endosomes include Rab7 and Rab9.