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Chromatography-based Biomolecule Purification Methods

JoVE 5683

In biochemistry, chromatography-based purification methods are employed to isolate compounds from a complex mixture. Two such methods used commonly by biochemists are size-exclusion chromatography and affinity chromatography. In size-exclusion chromatography, a column packed with porous beads separates components of a mixture based on size. On the other hand, affinity chromatography allows for …


 Biochemistry

Nuclear Magnetic Resonance (NMR) Spectroscopy

JoVE 5680

Source: Laboratory of Dr. Henrik Sundén – Chalmers University of Technology



Nuclear magnetic resonance (NMR) spectroscopy is a vital analysis technique for organic chemists. With the help of NMR, the work in the organic lab has been facilitated tremendously. Not only can it provide information about the structure…


 Organic Chemistry

Schlenk Lines Transfer of Solvents

JoVE 5679

Source: Hsin-Chun Chiu and Tyler J. Morin, laboratory of Dr. Ian Tonks—University of Minnesota Twin Cities


Schlenk lines and high vacuum lines are both used to exclude moisture and oxygen from reactions by running reactions under a slight overpressure of inert gas (usually N2 or Ar) or under vacuum. Vacuum transfer has been developed …


 Organic Chemistry

Scanning Electron Microscopy (SEM)

JoVE 5656

Source: Laboratory of Dr. Andrew J. Steckl — University of Cincinnati


A scanning electron microscope, or SEM, is a powerful microscope that uses electrons to form an image. It allows for imaging of conductive samples at magnifications that cannot be achieved using traditional microscopes. Modern light microscopes can achieve a…


 Analytical Chemistry

Detecting Reactive Oxygen Species

JoVE 5654

Reactive oxygen species are chemically active, oxygen-derived molecules capable of oxidizing other molecules. Because of their reactive nature, there are many deleterious effects associated with unchecked ROS production, including structural damage to DNA and other biological molecules. However, ROS can also be mediators of physiological signaling. There is accumulating…


 Cell Biology

The ATP Bioluminescence Assay

JoVE 5653

In fireflies, the luciferase enzyme converts a compound called luciferin into oxyluciferin, and produces light or “luminescence” as a result. This reaction requires energy derived from ATP in order to proceed, so researchers have exploited the luciferase-luciferin interaction to gauge ATP levels in cells. Given ATP’s role as the cell’s currency of…


 Cell Biology

An Introduction to Cell Metabolism

JoVE 5652

In cells, critical molecules are either built by joining together individual units like amino acids or nucleotides, or broken down into smaller components. Respectively, the reactions responsible for this are referred to as anabolic and catabolic. These reactions require or produce energy typically in the form of a “high-energy” molecule called ATP. Together,…


 Cell Biology

The TUNEL Assay

JoVE 5651

One of the hallmarks of apoptosis is the nuclear DNA fragmentation by nucleases. These enzymes are activated by caspases, the family of proteins that execute the cell death program. TUNEL assay is a method that takes advantage of this feature to detect apoptotic cells. In this assay, an enzyme called terminal deoxynucleotidyl transferase catalyzes the addition of dUTP…


 Cell Biology

Annexin V and Propidium Iodide Labeling

JoVE 5650

Staining with annexin V and propidium iodide (PI) provides researchers with a way to identify different types of cell death—either necrosis or apoptosis. This technique relies on two components. The first, annexin V, is a protein that binds certain phospholipids called phosphatidylserines, which normally occur only in the inner, cytoplasm-facing leaflet of a…


 Cell Biology

An Introduction to Cell Death

JoVE 5649

Necrosis, apoptosis, and autophagic cell death are all manners in which cells can die, and these mechanisms can be induced by different stimuli, such as cell injury, low nutrient levels, or signaling proteins. Whereas necrosis is considered to be an “accidental” or unexpected form of cell death, evidence exists that apoptosis and autophagy are both programmed…


 Cell Biology

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