About half a year ago,(I haven't been here for a long time) there was a thread somewhere about how humans could live forever if we simply take away the genes that make us look the way we are when we age. while after that, I was reading a Popular Science magazine that said that the reason why we age is because of the chemicals in the proteins we eat. They said that they actually attack and damage our genes, which makes us somewhat 'mutate', and that's how we 'grow old'. I was wondering if there have been any updates on this, new theories, related expiriments, or any thoughts that you may have.Please Register or Log in to view the hidden image! Please Register or Log in to view the hidden image! Please Register or Log in to view the hidden image!
The most recent theory on aging (I think it's the most recent anyways) involves telomeres, which are at the end of the DNA strands. These are there to protect the DNA from being damaged at the end. DNA replication is inefficient at the ends of the strand, so they are damaged that way. However, over time, the telomeres themselves get damaged, or aren't replicated correctly, and get shorter. Eventually, they disappear, and the ends of your DNA strand are susceptible to the damage that the telomeres were preventing (and enduring themselves). This causes the effects of aging. This is from memory, and I may be missing parts. If anyone wants to elaborate, or point out things I missed, please do.
Please Register or Log in to view the hidden image! Thanks for the reply, that idea seems to make sense. By the way, they had some evidence to back up the theory I mentioned. They took animals -before and after they were born- and gave them unusually high-protien diets. These animals were born weak and shrivelled, and already-born animals seemed to age many times faster than they should. However, stuffing lab monkeys full of proteins every day of their lives isn't really the healthiest thing to do Please Register or Log in to view the hidden image!
That does make sense. Think about it this way. Proteins are long polymers of monomer subunits (not exactly the correct term, but for getting the point across, it works) called amino acids. When you take proteins into your diet, you break them up into pieces, which are amino acids, and use those to synthesize the proteins used in your body. You do this because animal proteins can be different than human ones (most are likely very similar if we have the same ones), so we can't just use their proteins to make our own tissues. That, and most proteins are denatured during the cooking process. However, I am beginning to digress a little too far away from the topic. Which brings us to amino acids. The build-up of a lot of amino acids can cause a lot of problems. So, when you eat a lot of protein, you cannot synthesize proteins fast enough, and you begin to build up the amino acids in your blood stream. This can cause all sorts of problems, and would likely be the cause of the rapid aging that they were observing.
That does sound about right, but still, pumping monkey full of amino acids from proteins until they die can cause other problems than just destroying genes, as you said, and the monkeys they had tested died within weeks. Would the same problems occur (Besides the genes being destroyed) if the acids were given less frequently and in regular doses?
I've found a website loosely related to this topic, in a magazine article. I didn't get very much time to look at it, but it talks about something to do with folding and misfolding of proteins and the diseases caused by misfolding protiens. You can gind it at: http://folding.stanford.edu/
What I said in my previous post, is that since we only have two copies of each gene, we can only synthesize proteins so quickly. When we ingest a lot of protein, break it into the amino acids and can't use them fast enough, they build up. Some of them can be toxic and quite damaging in high concentrations. Improper folding can be due to a mutation in the DNA that codes for that particular protein, and causes an amino acid in the chain to be replaced by a different one. Since folding relies entirely on the amino acids interacting with eachother within the molecule, and the different acids having different chemistry, the protein can look different if even one amino acid out of 300 is different. If a protein folds incorrectly, but has the correct amino acid sequence, it can be refolded by larger proteins called "molecular chaperones". A lot of the large proteins (ones with long chains), are usually folded by molecular chaperones as soon as they leave the ribosomes, so there is less a chance of error. You are correct though, improperly shaped proteins can cause death rather quickly. As an interesting point, Mad Cow Disease, Scrapie (in sheep), Creutzfeld-Jakob (in humans), and Kuru (also in humans)are caused by virus-like particles of protein called prions. These proteins have identical amino acid sequences to a protein that is found in the respective animal, but is folded differently. The prion protein causes the regular to proteins to refold to the prion's shape. Having a different solubility in water (the prion is not soluble in water), you can see that a lot of problems will result. In Kuru, scrapie, and Mad Cow, cannibalism was the main mode of infection.
Ok, I get it now. I misinterpreted what you said. Please Register or Log in to view the hidden image!
I'll take this Aging is caused by many things, mainly its a mechanism against cancer. Theres three main forces in aging, there mutation buildup(caused by oxidants, verious mutagens), theres the reduction in telomeric length, and theres also the decrease in certain hormones in the endocrine system. The latter two try to work to minimize the effects of the first. By having a certain telomeric length, evolution has reduced the average lethality of a tumor. Some of them still turn into cancer(metastisize), but its a smaller number. Also its not a good thing to reach the minimal telomeric length, cause sometimes p53 does not kick in and properly arrest growth. So in addition to the telomeric length, certain cells within your brain(probably depending on their own telomeric length) reduce the production of hormones that WOULD normally cause growth. We can inject human growth hormone into old men and they start to look younger, larger muslce mass, smooth skin, etc. However we increase the number of cells that will reach their telomeric limit, and still continue dividing. Check the general science forum, I had a lengthy post there as well.
free aging From Nature vol 421 page 125-126 and 182-186 they knocked out the IGF-1r gene (insulin-like growth factor type 1 receptor). The homozygotes were not viable (in which both copies of the gene are not working), but the heterozygote was (which has one normal copy and one non-working copy). These mice lived on average 26% longer than normal wild type mice. Unfortunately the females lived longer than the males (since I am a male). The good news was that the mice were seemingly normal in every other aspect and didn't really develop serious problems. apparently IGFR works by recuding oxidative stress
Im actually I'm actually trying to get funding to look into something similar to that, anyway we have to wonder if its the decrease in the rate of growth, or primarily the decrease in the number of duplications that results in the lower cancer rate.
Re: Im actually wouldn't they have noticed the difference in growth rate by simply weighing them and comparing mouse sizes at different stages. I saw one comparison in the article and if I remember correctly they were the same size (wildtype and heterozygote). and for popcorn, i think that this is the thread: http://www.sciforums.com/showthread.php?s=&threadid=12048 'a non-chemical theory of aging'
I've read youngbiologist's first (of I believe many) replies to the subject, after flipping through about half a dozen pages. Some of the things you had to say were pretty interesting, and I'm beginning to see that there are many possible theories- proven or not- that describe how we age; and yours has been the most interesting so far. Please Register or Log in to view the hidden image!
well well I keep up with the latest stuff, there was a great website thats a shootoff from www.science.com that was concentrated on aging research news. Its called sage btw, but after january 1st of 2003 it costs 80 bucks to go to the website now. I'm still procrastinating about buying in, kinda expensive for just viewing a website, especially for an undergrad.
