tag:blogger.com,1999:blog-25425497.post116478463629473448..comments2011-11-18T22:26:00.006-08:00Anne Corwinhttp://www.blogger.com/profile/04940566603711834053noreply@blogger.comBlogger4125tag:blogger.com,1999:blog-25425497.post-1164954813921057722006-11-30T22:33:00.000-08:002006-11-30T22:33:00.000-08:00As an aside:<BR/><BR/><A HREF="http://www.cnn.com/2006/HEALTH/11/30/hand.transplant.ap/index.html" REL="nofollow">http://www.cnn.com/2006/HEALTH/11/30/hand.transplant.ap/index.html</A><BR/><BR/>It's a long way from growing someone a new hand from their own tissue, but we're getting there. :)403http://www.blogger.com/profile/08710944505136912842noreply@blogger.comtag:blogger.com,1999:blog-25425497.post-1164872104936001532006-11-29T23:35:00.000-08:002006-11-29T23:35:00.000-08:00nerdinium asked:<BR/><BR/><I>Are female ova special places where the degradation of mitochondrial DNA does not happen?</I><BR/><BR/>Funny you should ask that...I just came across <A HREF="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=pubmed&cmd=Retrieve&list_uids=17127355" REL="nofollow">this link</A>, which suggests:<BR/><BR/><I>Females live longer than males in many mammalian species, including humans. This natural phenomenon can be explained on the basis of the mitochondrial theory of aging. Mitochondria are a major source of free radicals in cells. Mitochondria from female rats generate half the amount of hydrogen peroxide than those of males and have higher levels of mitochondrial reduced glutathione. The latter is due to females behaving as double transgenic in over-expressing antioxidant enzymes. Estrogens bind to the estrogen receptors and subsequently activate the mitogen activated protein (MAP) kinase and nuclear factor kappa B (NFkappaB) signalling pathways, resulting in an upregulation of antioxidant enzymes. Moreover, the 16S rRNA expression, which decreases significantly with aging, is four times higher in mitochondria from females than in those from males of the same chronological age. On the contrary, the oxidative damage of mitochondrial DNA is fourfold higher in males than in females. Ovariectomy abolishes the gender differences between males and females and estrogen replacement rescues the effect of ovariectomy. The challenge for the future is to find molecules that have the beneficial effects of estradiol, but without its feminizing effects. Phytoestrogens or phytoestrogen-related molecules may be good candidates to meet this challenge.</I><BR/><BR/>As for whether it would be possible to infuse old cells with healthier newer mitochondria...I am just talking off the top of my head here, but these newly-infused mitochondria would need to harbor some kind of selective advantage over the nonfunctioning "mutants" that eventually take over the host cell. Part of the problem with the "mutants" is that they can sometimes escape being slated for destruction in the lysosome for longer than would be ideal, because the mutants can still have intact membranes. <BR/><BR/>Hence, the cell would still be vulnerable to take-over because it could be "tricked" into harboring nonfunctioning mitochondria and allowing these mutants to reproduce and eventually take over, edging out the healthy mitochondria you added. I suppose adding healthy mitochondria periodically might confer some benefit (at least, I can't see why not at the moment) but I am more intrigued by the idea of moving the mtDNA into the nucleus, since evolution has already started that process, and the nucleus is a far "friendlier" environment for such things. <BR/><BR/>If this were accomplished it wouldn't matter if the local mtDNA mutated, because the proper proteins necessary for mitochondrial functioning would still be produced according to the instructions now contained in the nucleus.AnneChttp://www.blogger.com/profile/04940566603711834053noreply@blogger.comtag:blogger.com,1999:blog-25425497.post-1164850954099798272006-11-29T17:42:00.000-08:002006-11-29T17:42:00.000-08:00I'm confused - I know from previous reading that mitochondria are the descendants of once free swimming bacteria that entered into a symbiotic relationship with a different type of bacteria to form our own and all eukaryotic cells. They supply energy to the cell, and will reproduce if more energy is needed - from 70 up to several hundred mitochondria in each cell. Are female ova special places where the degredation of mitochondrial DNA does not happen? <BR/><BR/>I was also wondering would it be possible to infuse old cells with healthier newer mitochondria, as they are able to reproduce by themselves within the cell, and as far as I know wouldn't be rejected as they are a symbiote. Do you know (I don't) of anyone that has managed to culture mitochondria outside of the interior of a cell? The only site I was able to find was this one, but the fellow tried it in the 1920s:<BR/><BR/>http://www.dnaftb.org/dnaftb/concept_30/con30bio.htmlNerdiniumhttp://www.blogger.com/profile/11237835436251481464noreply@blogger.comtag:blogger.com,1999:blog-25425497.post-1164808094482981912006-11-29T05:48:00.000-08:002006-11-29T05:48:00.000-08:00> advances anywhere in biotech have the potential to advance SENS science<BR/><BR/>One way to contribute to and learn about biotech research is to participate in distributed computing biotech projects like for instance <A HREF="http://www.rosettaathome.org/" REL="nofollow">Rosetta@home</A> (info on Rosetta@home is available in <A HREF="http://betterhumans.com/forums/thread/6658.aspx" REL="nofollow">this</A> Betterhumans forum thread).hoelder1inhttp://betterhumans.com/forums/thread/6658.aspxnoreply@blogger.com