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1

There are two things happening: First melanin absorbs the energy from the UV radiation and releases it as infrared energy and thus protects the cells in the skin. This happens in all people, the deeper the skin color is, the better is the protection. What is different between people is the amount of pigment they produce, the number of melanocytes is ...


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Some additional details on the same lines as Chris' answer: Coelho et al. have studied the short and long term effects of UV on human skin and they report that there are different stages of tanning: Immediate pigment darkening: happens in a few minutes and persists for some hours. It is most probably due to melanosome redistribution and melanin oxidation ...


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When our skin is exposed to the sun, this can cause some damage in the upper layers of skin. This activates DNA damage repair and also induces signalling towards the melanocytes (which produce the pigment). Signalling means the excretion of signalling molecules (mostly alpha-Melanocyte stimulating hormone, aMSH) which binds to the MC1R receptor (melanocortin ...


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First, one should mention types of skin: skin type defines how the person will tan - Second, the solar radiation (UV) absorbed by sun defines the amount of melanin produced by melanocytes of the skin to protect the skin = melanogenesis (which in turn depends on skin type). When the solar exposure diminish, the natural repair processes causes ...


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Necrotic cells could be trypan blue positive. WST-1 Assay could reflect cell number by measuring mitochondrial dehydrogenase, therefore, you could not know how many cells die in dishes. When you define apoptosis in your experiment as caspase dependent cell death, measuring caspase activity is the best. PS Trypan Blue Staining actually is a method to see ...


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It's commonly believed that it's muscle cells that have the largest amount of mitochondria, and for good reason. Muscle cells are continually used to move the body, so they have the most mitochondria because of the large energy requirement. If you want to be more specific, the muscle cells of a marathon runner have even more since the muscle cells involved ...


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The secretion pushes the cell organelles to the basal part. (although the fat cells have no polarity, their organelles have been pushed to one side of the cell: Comparing to adipose cells, the acinar cells secrete their specific proteins on one specific end of the cell, this is why in contrast with fat cells they have well defined polarity.


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A simple method would me to express a fluorescent protein in the cell that specifically localizes to mitochondria. mito-dsRed is a Red Fluorescent Protein which has that property; it can be expressed from a plasmid. Using fluorescent microscopy and image analysis, you would be able to measure the geometric properties of the mitochondria. This can be done at ...


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The reason why the cell would shrink more in CaCl2 solution is because it has a higher van't Hoff factor i.e. total number of dissociated ionic species per solute molecule (it is 2 for NaCl whereas it is 3 for CaCl2). (Nonionic solutes do not dissociate and will therefore have a van't Hoff factor of 1) Osmotic pressure (and other colligative properties) ...


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I can't find the LG2 cell line that you mentioned but often times you can find karyotype information on ATCC or COSMIC (for cancer cells)


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Cancer is successful at killing it's victims because it is genetically still very similar to the host. The immune system does not respond to it sufficiently to eradicate the mutated cells and this allows it to grow out of control. When dealing with any kind of transmittal this would be close to an organ donation. Without a very close match, and ...


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Although transmissible cancer has been found in some species, such as Tasmanian Devils and clams, it is quite rare in most species. Certain viral and bacterial agents that cause cancer, however, can be transmitted. One example is HPV, which can cause cervical cancer


1

Might be considered "not answering the question" but: Option 1: Depending on the type of cells you are using, you can use milder methods to detach cells. Example include Versene which is essentially PBS + EDTA. Milder still is to just use PBS that has no Mg or Ca (no chelation). Option 2: Duplicate your setup - instead of two dishes - one with drug, one ...


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Most ligands are synthesized as the same way as receptors integrated in membrane: synthesized on rough-ER, pulled into the lumen of ER. If proteins synthesized on rough-ER have a hydrophobic amino acid sequence, the hydrophobic region could stay in membrane because inside of membrane is hydrophobic and has affinity to hydrophobic amino acid sequences. ...


6

A perfectly reasonable definition of a ligand from Wikipedia: In biochemistry and pharmacology, a ligand is a substance that forms a complex with a biomolecule to serve a biological purpose. A ligand can be anything, so long as it binds to a biomolecule. Often, the ligand is a small molecule or peptide, and the thing that it binds to is a protein. On ...


5

In biology ligand is a very broad term. Everything is called a ligand that has a receptor for it, regardless whether it is free or membrane-bound. There is very much sense in membrane bound ligands, because many cells in our body are capable of actively moving around (for example T-cells). Cells can use signal transduction by direct cell-to-cell contact - ...


2

It would be stressful for cells to be trypsinized 24 hours after seeding. After cells are plated, there is a lag time to start growing. Perhaps, during the lag time, physiological state of cells is stabilized. They have to express proteins digested by trypsin and display on the surface etc. Then you could disturb the state again by trypsinizing cells again ...


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It is not advisable to trypsinize the cells too often when you have to maintain them. However, in your case the situation is different. Time required to attach depends on cell type. In any case while performing an experiment, your cells should not be already under stress. Therefore you should seed the flasks/culture plates with a smaller concentration of ...


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There is a reasonable speculation. That is to get more areas where ATP synthases are localized in order to produce ATP. But this doesn't tell why the structure has to be the exactly that shape. As the review Ilan show, the shape seems to be determined by ATP synthase dimerizetion. The shap may be just a consequence of ATP synthase dimerizetion, although ...


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It is not possible to know in most cases whether a chromosome is maternal or paternal without knowing the genome sequence of both mother and father (with some additional effort; see below). There are certain exceptions and these include chromosomes that bear imprinted genes. For example H19 gene on chromosome-1 is maternally imprinted i.e. the paternal ...


4

TGF-beta would be a good candidate. To cite: "TGF-β inhibits G1/S progression in a variety of eukaryotic cell types. Among these, untransformed epithelial cells are particularly sensitive to the growth inhibition by TGF-β." http://genesdev.cshlp.org/content/14/24/3093.full Fetal bovine serum (FBS) contains a high level of latent TGF-β. Human serum as well ...


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The cytogenetic notation seems to refer to parts of the chromosome when they're being karyotyped when the chromsomes are condensed in metaphase. If so, I think you might be able to use FISH to look for pieces of maternal or paternal genetic content on the chromosome. It looks like you can use mat and pat to refer to a maternal or paternal chromosome.



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