borgqueenx
Well-Known Member
Sigh, i'm so tired of waiting, give me something to doooo!!!
post crappy photos now so we can laugh.
post crappy photos now so we can laugh.
Hibernation is one of the many mysteries of modern science. Anatomical and behavioral studies have revealed very little about the inner workings of this amazing ability. Hibernating animals can to lower their body temperature to 2° C and their heart rate to 2 beats per minute, while reducing their intake of oxygen to 1/50 of their waking levels. All of this occurs without consuming food and can last for as long as 6 months. Current progress in biochemistry and genetic research has finally started to enable our knowledge to catch up to our curiosity in this field. Several different factors have been discovered for the process of reducing the metabolic activity of the body and maximizing its efficient use of energy. Interestingly enough, the same genes may be latent in human beings.
While hibernating animals reduce their metabolic rate substantially, they still need to keep their bodies warm. The protein thermogenin has been found to uncouple the electron transport chain from the process of making adenosine triphosphate (ATP). The result is the production of heat, thermogenesis, instead of the ATP energy that would be usable by the body. The electron transport chain is a series of membrane proteins, which, in the processes of metabolizing food or food reserves, produces a very high concentration of hydrogen ions in the inter-membrane space of a mitochondrion. The matrix of the mitochondrion, which has relatively few hydrogen ions, and the intermembrane space are separated by a single lipid bilayer membrane. The result is an imbalance much like that of the waters on either side of a dam. On power producing dams there are generators that are able to convert the energy produced by the movement of the water through the dam into useable electricity. The generator of the mitochondria is called an ATP synthetase. ATP is the basic currency of energy used to drive most of the bodys functions. The generators make ATP by using the energy of the hydrogen ion movement across the membrane to attach a phosphate group to ADP. Thermogenin works by leveling the water on both sides of the dam. Its as if someone were to poke a hole into the dam so that water could flow to the other side without passing through the generator. In the case of the mitochondrial inner membrane the "hole" is a protein channel from the intermembrane space to the matrix. The energy that would have been converted to ATP is then released as heat. The presence of thermogenin in high quantity produces a darker color in animal adipose tissue, commonly called brown fat.
Uncoupling proteins (UCPs) are members of the mitochondrial transport carrier family, and have been implicated in a wide range of physiological and pathological conditions. Physiological conditions include thermogenesis, fatty acid metabolism and protection against free radicals and ageing; pathological conditions include involvement in obesity, diabetes and degenerative, neurological and immunological diseases.
The UCPs share general structural features with the other mitochondrial transport carriers. They have a tripartite structure, consisting of three homologous sequence repeats of approximately 100 residues. The carriers also have a signature motif, which is repeated in all members of the family and in all three repeats. The transmembrane arrangement of UCPs is 6 alpha-helix regions (2 regions per repeat) spanning the lipid bilayer with the amino and carboxyl termini facing the cytosolic side. The crystal structure of one member of the family, the adenine nucleotide translocase, is known, and UCPs can be successfully folded into this structure to indicate their probable 3D arrangement (Pebay-Peyroula et al., 2003; Kunji, 2004; Esteves and Brand, 2005).
The paradigm of this family, UCP1, catalyzes adaptive thermogenesis (i.e. heat generation) in mammalian brown adipose tissue. It does so by promoting a leak of protons through the mitochondrial inner membrane, which uncouples ATP production from substrate oxidation, leading to fast oxygen consumption and ultimately to heat production. The thermogenic activity of UCP1 in brown adipose tissue plays an important role when the organism needs extra heat, e.g. during cold weather conditions (for small rodents), the cold stress of birth and arousal from hibernation. UCP1 homologs have also been found in lower vertebrates such as fish, where their role is still unclear (Cannon and Nedergaard, 2004; Jastroch et al., 2005).
The proton conductance of UCP1 in brown adipose tissue is tightly controlled. It is strongly inhibited by purine nucleotides at physiological concentrations, and this inhibition is overcome by fatty acids, which are released from intracellular triacylglycerol stores following adrenergic activation in response to cold or overfeeding.
In the late 1990â€s, UCP2 and UCP3 were identified. These new UCPs have high amino acid sequence homology to UCP1 (59 and 57% amino-acid identity to UCP1, respectively). UCP2 has been identified in lung, spleen, pancreatic beta-cells and kidney, whereas UCP3 is found in brown adipose tissue and skeletal muscle. Homologs of UCP2 and UCP3 are found in marsupials, birds, fish and plants.
UCP2 and UCP3 only catalyze proton leak when activated. These proteins will transport protons and increase the net proton conductance of mitochondria in the presence of specific activators, in a way that is inhibited by purine nucleotides. Activators include superoxide, retinoic acid, the retinoid 4-[(E)-2-(5,6,7,8-tetrahydro-5,5,8,8-tetra-methyl-2-naphtalenyl)-1-propenyl]benzoic acid (TTNPB) and reactive alkenals, such as hydroxynonenal. Activation might require fatty acids. UCP1 is also activated by these compounds.
There is strong evidence that the regulated uncoupling caused by these proteins attenuates mitochondrial reactive oxygen species production, protects against cellular damage, and (in beta-cells) diminishes insulin secretion. There are also untested suggestions that their transport of fatty acids may be physiologically important (Brand and Esteves, 2005; Esteves and Brand, 2005; Krauss et al., 2005).
A number of models have been proposed for the molecular mechanism by which fatty acids lead to increased proton conductance by UCP1 in brown adipose tissue mitochondria, and presumably by the other UCPs as well. These are the "fatty acid cycling" model and the "proton buffering" model.
mali said:@Bosbeetle
Good to know![]()
The body has got some nifty techniques rarely known. I read about some kind of self-curing hibernation a while ago. I don't have links and it was in German anyway. A surgeon introduced a technique to operate people who wouldn't have survived an immediate surgery. He covered the open body with foil to prevent infection and let them rest for a night. He could continue the surgery the next day, as the body had regenerated partly.
Another interesting (true) story from the local newspaper. A family found their youngest child with one arm removed sleeping in bed. What happened? The young boy played with his elder brother with a washing machine. The young boy had his arm inside when the machine began rotation and ripped off his arm. The elder brother was in panic to be punished for this, so he hid the arm and put his brother in bed. The shock prevented the younger brother from feeling pain and the fact that the arm was ripped off let the veins curl up and stopped bleeding instantly.
mali said:
There might as well be things we just can't use right now. Latest studies revealed that inactive genes are switched on and off depending on outside conditions. So Lamarque wasn't _completely_ wrong as the condition of these genes enters the germ lineBosbeetle said:Sadly 'we' humans can not utilize this. That's why we cant go into hibernation.
mali said:There might as well be things we just can't use right now. Latest studies revealed that inactive genes are switched on and off depending on outside conditions. So Lamarque wasn't _completely_ wrong as the condition of these genes enters the germ lineBosbeetle said:Sadly 'we' humans can not utilize this. That's why we cant go into hibernation.![]()
YESBeholder said:This reminded me... Would not the "Han Solo Frozen In Carbonite Desk" be the ultimate "Pimp My Office" hallmark item?
B-b-bu-but...That chair costs like....FIVEHUNDREDANDNINETYNINEYOUESSDOLLARS!!!!!!Fzero said:that chair shown is pretty weak though, this table deserves nothing less than the villian chair
http://www.suck.uk.com/product.php?rangeID=55