Aquaporins

Biology. Water Research. Aquaporins Claymation Project. Life Sciences. Aquaporin-mediated transport. Aquaporins.org l Integral Membrane Proteins. Aquaporins. Water crosses cell membranes by two routes: by diffusion through the lipid bilayer and through water channels called aquaporins.

Functional characterization of the first aquaporin was reported in 1992, but water channels were suspected to exist well before that time, because the osmotic permeability of some types of epithelial cells was much too large to be accounted for by simple diffusion through the plasma membrane. A single human aquaporin-1 channel facilitates water transport at a rate of roughly 3 billion water molecules per second. Such transport appears to be bidirectional, in accordance with the prevailing osmotic gradient. Precious Bodily Fluids [PSC] If you could travel through the body, a swamp boat might be a good vehicle.

Structure, Dynamics, and Function of Aquaporins. The Art of Water Transport in Aquaporins Aquaporins are membrane water channels that play critical roles in controlling the water contents of cells.

These channels are widely distributed in all kingdoms of life, including bacteria, plants, and mammals. More than ten different aquaporins have been found in human body, and several diseases, such as congenital cataracts and nephrogenic diabetes insipidus, are connected to the impaired function of these channels. They form tetramers in the cell membrane, and facilitate the transport of water and, in some cases, other small solutes across the membrane. However, the water pores are completely impermeable to charged species, such as protons, a remarkable property that is critical for the conservation of membrane's electrochemical potential, but paradoxical at the same time, since protons can usually be transfered readily through water molecules.

The hydrosphere and the oceans. Where did the water come from?

It appears to have been bound up in the silica-based materials such as micas and amphiboles which accreted to form the Earth. The heat released during this process would have been sufficient to drive off this water, which amounted to about 0.01% by mass of the primoridal material. The Structure of Liquid Water. Return to Home Page A Time-Averaged, Semi-Classical Model Abstract Ideal liquid water is here defined as a pure, (microcanonical) collection of water molecules in the liquid state without hydroxide or hydronium ions.

This interstitial structure is described pictorially using geometry and mathematically using the thermodynamic partition function. The combined descriptions potentially make liquid water completely computerizeable. After thoroughly examining the water molecule, a first approximation is made that the liquid structure is roughly the hexagonal cell structure of ice with the appropriate number of interstitial molecules needed to reproduce the observed density of a given temperature given the inter-molecular lengths seen by x-ray at that temperature. Next a molecular stick-figure of these hexagonal cells is drawn with the interstitial molecules placed to minimize the inter-molecular electrical potential energy.

Symmetry, Selectivity, and the 2003 Nobel Prize. To view the full text, please login as a subscribed user or purchase a subscription.

Click here to view the full text on ScienceDirect. Figure 1 Rod MacKinnon (Right) with Former Mentor, Chris Miller Photo courtesy of Robin Miller. Redirection page. Molecular Anatomy of a Trafficking Organelle. Open Archive Summary Membrane traffic in eukaryotic cells involves transport of vesicles that bud from a donor compartment and fuse with an acceptor compartment.

Common principles of budding and fusion have emerged, and many of the proteins involved in these events are now known. However, a detailed picture of an entire trafficking organelle is not yet available. Using synaptic vesicles as a model, we have now determined the protein and lipid composition; measured vesicle size, density, and mass; calculated the average protein and lipid mass per vesicle; and determined the copy number of more than a dozen major constituents. Introduction. L'eau du robinet n'est pas conforme à la bio-électronique. Eau douce ou eau dure ?

(mise à jour du lundi 2 décembre 2013) Remarque préliminaire - Ce document (rédigé en liaison avec un groupe de médecins, pharmaciens, dentistes, chimistes, et autres experts en cette complexe matière) adopte un style délibérément dogmatique afin de rendre son contenu plus clair et plus accessible. Le terme « eau pure » ou « ultrapure » est par exemple un euphémisme ou raccourci pratique car une telle eau relève plus de la théorie que de la réalité physique.

Les recherches scientifiques sur l’eau sont loin d’être terminées et de nombreux « bémols » dus à la complexité du sujet seraient à apporter à ce texte pour qu’il puisse être qualifié de « scientifique », comme me l’a fait remarquer le biophysicien Yann Olivaux) Aquaporins: Stimulation by Vitamins, Steroids and Sugar Alcohols. Nov 1, 2008 | Contact Author | By: Bud Brewster, C&T magazine Save To Save to My Library You must Create an Account with Cosmetics & Toiletries and you will get FREE access to: the My Library toolCosmetics & Toiletries magazine content andThe ability to save and share information with your peers.

Start to build your own personal library by registering now. Create an Account or Log InCancel Article Media Keywords/Abstract Excerpt Only This is a shortened version or summary of the article you requested. Aquaporins are proteins that reside in the cellular membrane. Close Save Z-COTE LSA provides broad-spectrum protection from long wave UVA rays and medium wave UVB rays by physically scattering, reflecting and absorbing solar radiation. Zinc Oxide Triethoxycaprylylsilane Functions UVA, UVB Sunscreen. Cell. Hydra IQ.