Cell Biology Terms Starting With W
Cell Biology Glossary: W
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Western Blotting
/ WES-tern BLOT-ing / · Named informally after Southern blotting (Edwin Southern)
Western blotting is a laboratory technique that separates proteins by molecular weight using gel electrophoresis, then uses antibodies to identify a specific protein transferred onto a membrane.
Scientists apply a protein mixture to a polyacrylamide gel and run an electric current through it, causing smaller proteins to migrate farther than larger ones. The separated proteins are then transferred onto a nitrocellulose or PVDF membrane where they bind tightly. Primary antibodies specific to the target protein bind it on the membrane, followed by secondary antibodies linked to enzymes or fluorescent labels that produce a visible band.
Harry Towbin developed the method in 1979, and modern protocols can detect proteins at concentrations as low as 0.1 nanograms, making it one of the most sensitive protein detection tools in cell biology.
A single Western blot can distinguish between two proteins that differ in molecular weight by as little as 1 to 2 kilodaltons, provided the gel percentage is optimized for that size range. This resolution has made the technique indispensable for confirming post-translational modifications such as phosphorylation, which shifts a protein's apparent molecular weight by only a few kilodaltons.
Western blotting measures DNA. Proteins are its target, while Southern blotting detects DNA and Northern blotting detects RNA.
Building Blocks of Nucleic Acids →Researchers studying breast cancer cells use Western blots to measure HER2 protein levels before and after treatment with the drug trastuzumab. A band appearing at approximately 185 kilodaltons on the membrane confirms HER2 presence, and band intensity quantified by densitometry reflects relative protein abundance across treatment conditions.
Wound Response
/ WOOND rih-SPAWNS / · From Old English wund meaning injury and Latin respondere meaning to answer or reply.
Wound response is the coordinated set of cellular and molecular events activated after tissue injury to restore barrier function, clear damaged cells, and rebuild lost tissue.
Hemostasis initiates within seconds of injury as platelets aggregate and form a fibrin clot, releasing growth factors including PDGF and TGF-beta that recruit immune cells to the site. Inflammation peaks within 24 to 48 hours as neutrophils and macrophages infiltrate the damaged area, clearing debris and secreting cytokines that stimulate cell proliferation. During the proliferative phase, which lasts roughly 4 to 14 days, fibroblasts deposit collagen while epithelial cells migrate across the wound bed at rates approaching 0.5 millimeters per day.
Angiogenesis restores blood supply through VEGF-driven endothelial sprouting, and the subsequent remodeling phase extends over months as matrix metalloproteinases convert weaker type III collagen to stronger type I. Even single-celled organisms such as amoebae display a rapid wound response, recruiting actin and myosin to reseal membrane breaches within 3 to 40 seconds.
Endogenous electric fields form naturally at wound edges, reaching strengths of 40 to 200 millivolts per millimeter. These voltages actively guide epithelial cell migration through a process called galvanotaxis, and disrupting them significantly impairs healing rates in experimental models.
Wounds do not heal faster when kept dry and exposed to air. Moist wound environments accelerate epithelial migration by up to 50 percent compared with dry conditions, which is why occlusive dressings are preferred in clinical wound management.
African spiny mice (Acomys cahirinus) can regenerate full-thickness skin wounds spanning 4 millimeters without scarring, completely restoring hair follicles and sebaceous glands within 30 days. This mammalian regenerative capacity rivals that traditionally seen only in salamanders and suggests latent healing programs exist across a broader range of mammals than previously recognized.