September 16, 2002

Today, I have:
(1)  Updated the Prolongevity Index
(2)  Further updated yesterday's Prolongevity_Index
(3)  Moved some of the materials on the front (index) page of the website to their appropriate indices.
(4)  Investigated longevity research sites and gathered information concerning alleged  health-promoting supplements. (I won't post that until I have a clearer picture of what's recommended and why, but one of the supplements will be carnosine.)

    It's clear that the immortality or rejuvenation of germ cells is understood among those interested in the mechanisms of aging. As John Furber puts it,

 "It is noteworthy that the germ line of egg and sperm has been maintained alive and safe from senescence and oxidative decay for over a billion years. Our life is part of an unbroken chain of life, extending back in time to our earliest ancestors.

"Most of the biochemical reactions of life were developed long ago in single-celled organisms and bacteria, long before multicellular organisms arose. These single-celled organisms reproduced by dividing into two equal halves. Neither half was parent or child. Their descendants are still thriving today, living and dividing, and apparently not senile. Consequently, it is attractive to think of these protista and monera as never aging. However, there is evidence that the processes of growing and dividing are important factors in maintaining the youthful state of these cells."

    The prevailing view seems to be that germ cells keep themselves in a state of perfect repair, rather than rejuvenating when reproduction occurs. However, as John Furber has observed, there's some indication that growing and dividing is important in the maintenance of juvenescence.
    It seems to me that the question then becomes: How do germ cells completely prevent (or completely repair) free radical damage? What do they do about the cross-linking (toughening up) of "junk" inside the cell? What biochemical molecules do they use to either prevent or repair such mishaps? A company called "Alteon Pharmaceuticals" is testing a drug called ALT-711 that would restore elasticity to skin and arterial walls (lowering blood pressure). Presumably, ALT-711 is a synthetic compound. What do germ cells use to accomplish this function?  And so forth. What does Nature use to avoid or repair all the age-related damage that occurs to  somatic cells?
    A crucial point, I think, is that whatever mechanisms are involved, they have to be present in all living species! (I'm excluding viruses from my definition of "living organism".) But this would suggest that the same machinery should be present in large classes of "germ cell" organisms, if not all of them. It means that all unicellular organisms (protista and monera) must possess this machinery. And unicellular organisms must have had this digital, error-correcting machinery in place from the very beginning, so that they could create accurate replicas of themselves. 
    This raises interesting questions. I have the impression that different bacteria employ different DNA repair enzymes. Maintaining the integrity of the genome would seem to be required to pass a perfect copy of it along to daughter cells. Are there many DNA repair enzymes that can maintain a perfectly-clean genome? The example of deinococcus radiodurans comes to mind. Looking at it, it seems clear that not all DNA repair enzymes can perfectly repair genomes for reproduction under all circumstances. 

   So far, I haven't seen any mention made of this.