线粒体荧光探针信息大全 （Probes for Mitochondria）包括各种常用探针，如JC-1，JC-9，TMRM，TMRE等
Mitochondria are found in eukaryotic cells, where they make up as much as 10% of the cell volume. They are pleomorphic organelles with structural variations depending on cell type, cell-cycle stage and intracellular metabolic state. The key function of mitochondria is energy production through oxidative phosphorylation (OxPhos) and lipid oxidation.1,2 Several other metabolic functions are performed by mitochondria, including urea production and heme, non-heme iron and steroid biogenesis, as well as intracellular Ca2+ homeostasis. Mitochondria also play a pivotal role in apoptosis — a process by which unneeded cells are removed during development, and defective cells are selectively destroyed without surrounding organelle damage in somatic tissues 3–5 (Section 15.5). For many of these mitochondrial functions, there is only a partial understanding of the components involved, with even less information on mechanism and regulation.
Visualizing Mitochondria in Cells and Tissues
The morphology of mitochondria is highly variable. In dividing cells, the organelle can switch between a fragmented morphology with many ovoid-shaped mitochondria, as often shown in textbooks, and a reticulum in which the organelle is a single, many-branched structure. The cell cycle– and metabolic state–dependent changes in mitochondrial morphology are controlled by a set of proteins that cause fission and fusion of the organelle mass. Mutations in these proteins are the cause of several human diseases, indicating the importance of overall morphology for cell functioning (see Note 12.2 "Technical Focus: Mitochondria in Diseases"). Organelle morphology is also controlled by cytoskeletal elements, including actin filaments and microtubules. In nondividing tissue, overall mitochondrial morphology is very cell dependent, with mitochondria spiraling around the axoneme in spermatozoa, and ovoid bands of mitochondria intercalating between actomyosin filaments. There is emerging evidence of functionally significant heterogeneity of mitochondrial forms within individual cells.
The abundance of mitochondria varies with cellular energy level and is a function of cell type, cell-cycle stage and proliferative state. For example, brown adipose tissue cells,6 hepatocytes 7 and certain renal epithelial cells 8 tend to be rich in active mitochondria, whereas quiescent immune-system progenitor or precursor cells show little staining with mitochondrion-selective dyes.9 The number of mitochondria is reduced in Alzheimer's disease and their protein and nucleic acids are affected by reactive oxygen species, including nitric oxide 10 (Chapter 18).
Molecular Probes has a range of mitochondrion-selective dyes with which to monitor mitochondrial morphology and organelle functioning. The uptake of most mitochondrion-selective dyes is dependent on the mitochondrial membrane potential; nonyl acridine orange and possibly our MitoTracker Green FM, MitoFluor Green and MitoFluor Red 589 probes are notable exceptions, although their membrane potential–independent uptake and fluorescence has been questioned in some cell types.11,12 Mitochondrion-selective reagents enable researchers to probe mitochondrial activity, localization and abundance,13,14 as well as to monitor the effects of some pharmacological agents, such as anesthetics that alter mitochondrial function.15 Molecular Probes offers a variety of cell-permeant stains for mitochondria, as well as subunit-specific monoclonal antibodies directed against proteins in the oxidative phosphorylation (OxPhos) system, all of which are discussed below.
