Dnatube Scientific Videos

In Situ Hybridization (ISH)
In Situ Hybridization (ISH), a technology for gene expression analysis. is a type of hybridization that uses a labeled complementary DNA or RNA strand (i.e., probe) to localize a specific DNA or RNA sequence in a portion or section of tissue (in situ), or, if the tissue is small enough (e.g. plant seeds, Drosophila embryos), in the entire tissue (whole mount ISH).
Tags // In Situ Hybridization
Added: November 23, 2010, 11:55 pm
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Secondary Messenger System and Insulin
Insulin and the Second Messenger System. nsulin is a hormone. And like many hormones, insulin is a protein. Insulin is secreted by groups of cells within the pancreas called islet cells. Second messengers are molecules that relay signals from receptors on the cell surface to target molecules inside the cell, in the cytoplasm or nucleus. They relay the signals of hormones like epinephrine (adrenalin), growth factors, and others, and cause some kind of change in the activity of the cell. They greatly amplify the strength of the signal.Secondary messengers are a component of signal transduction cascades. Read more: http://en.wikipedia.org/wiki/Second_messenger_system
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Added: November 23, 2010, 11:58 pm
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Insulin secretion process animation
Insulin secretion process. Insulin is secreted in primarily in response to elevated blood concentrations of glucose. This makes sense because insulin is "in charge" of facilitating glucose entry into cells. Some neural stimuli (e.g. sight and taste of food) and increased blood concentrations of other fuel molecules, including amino acids and fatty acids, also promote insulin secretion. Our understanding of the mechanisms behind insulin secretion remain somewhat fragmentary. Nonetheless, certain features of this process have been clearly and repeatedly demonstrated, yielding the following model: Glucose is transported into the beta cell by facilitated diffusion through a glucose transporter; elevated concentrations of glucose in extracellular fluid lead to elevated concentrations of glucose within the beta cell. Elevated concentrations of glucose within the beta cell ultimately leads to membrane depolarization and an influx of extracellular calcium. The resulting increase in intracellular calcium is thought to be one of the primary triggers for exocytosis of insulin-containing secretory granules. The mechanisms by which elevated glucose levels within the beta cell cause depolarization is not clearly established, but seems to result from metabolism of glucose and other fuel molecules within the cell, perhaps sensed as an alteration of ATP:ADP ratio and transduced into alterations in membrane conductance. Increased levels of glucose within beta cells also appears to activate calcium-independent pathways that participate in insulin secretion. Stimulation of insulin release is readily observed in whole animals or people. The normal fasting blood glucose concentration in humans and most mammals is 80 to 90 mg per 100 ml, associated with very low levels of insulin secretion. Read more: http://www.vivo.colostate.edu/hbooks/pathphys/endocrine/pancreas/insulin.html
Tags // Insulin secretion process
Added: November 24, 2010, 12:01 am
Runtime: 76.16 | Views: 3139 | Comments:0
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