Rapamycin increases lifespan in mice
Lynne Cox wrote an article on the BSRA News Section about the recent Nature paper by David Harrison and colleagues: Rapamycin fed late in life extends lifespan in genetically heterogeneous mice; Nature 460, 392-395 (16 July 2009); doi:10.1038/nature08221; Published online 8 July 2009. This paper was also reported in a news item by Matt Kaeberlein and Brian Kennedy also within that Nature issue.
Here’s a portion of Lynne’s article:
“Rapamycin (C51H79NO13), now more correctly known as sirolimus, is a macrolide antibiotic produced by the soil bacterium Streptomyces hygroscopicus, initially found on Easter Island in the South Pacific. Perhaps this is one of the reasons why the media hype surrounding this story grew to such proportions: Easter Island is renowned for its mysterious monoliths, and it might be easy for the superstitious to find some sort of connection between this mystery and the so-called “elixir of youth”. More prosaically, the biosynthetic pathway of rapamycin, mediated by a series of bacterial Rap genes, is known and the drug is manufactured commercially, disconnecting it from its ‘mysterious’ origins.”
This study on mice lifespan is all good. However, it has to be reiterated — rapamycin is a potent immunosuppressant.
Twiggy and Ageing
I cannot avoid mentioning that Twiggy, the so called “The Original Supermodel” is turning 60. And it is without doubt that she still remains in the limelight and continues to be a darling of the press. She recently published a book on ageing, for women above 40. I reckon this book is partly autobiographical too. What is inside the book intrigues me. Check her out.
how old was he
I overheard this conversation today, about a person who died recently:
Lady 1: How old was he?
Lady 2: 63
Lady 1: Oh I see. I would have been surprised if he was in his 40s or younger.
It struck me that there seems to exist a notion that older people have more reason to die than younger people. Why is that? Why can’t we think that anybody, regardless of age, has the same chance of dying anytime anywhere as anyone else? I thought this might have something to do with how people perceive old age. Despair appears to dominate the experience of getting older. It is like waiting for your own self-destruction … is it really?
(c/o Jo Burt)
vintage and the hamburger bed
If you have not heard of it yet, do not be alarmed, you are only missing a bed. Yes, it a real bed, a real hamburger bed. It went on sale as of July 16 on Ebay. Apparently, it has been featured in seven magazines and over 100 blogs. What a remarkable, world-famous, handmade hamburger bed. Should you decide to purchase it, you will not only own the bed, but the official Hamburger Bed website and its Facebook fan page with 12,000 fans too. It does look like a good bargain. You never run out of that lovely burger as you get old. Now I’m off to a vintage fair and will try my luck on any vintage hamburger bed paraphernalia.
for the sake of time
Looks like we’re going to give up the benzonase mystery soon. We are a bit constrained by time. Solving the benzonase mystery seems to be an exciting prospect. However, we will have to carry on with our purification efforts.
the benzonase mystery
Recently, we have been intrigued by the association of benzonase and our molecule of interest. And so I thought it might be handy to dig up information on benzonase. Benzonase is the commerical version of the extracellular endonuclease from the pathogenic enteric Gram-negative bacterium Serratia marcescens (1-4). It is composed of a single polypeptide chain (245 residues, Mr 26,700). It is capable of digesting DNA and RNA, both single- and double-stranded. Similar to DNase I, it is magnesium-dependent and catalyzes the cleavage of the 3′ O-P bond (4). In addition to its broad specificity, it retains catalytic activity even in extreme conditions such incubation with 4 M urea (7). Now, the mystery involves the formation of precipitates upon incubation of our clear lysate with benzonase. SDS-PAGE of the supernatant and the precipitate indicated that our molecule of interest is is in the precipitate, and not in the supernatant. Upon solubilisation of that precipitate (or pelle) with another round of lysis buffer, followed by SDS-PAGE, resulted into the similar gel profile of our molecule of interest showing up in the precipitate and not in the supernatant. What is going on?
References:
1) Product Specifications for Benzonase, The first industrial endonuclease. (Benzon Pharma A/S, Helseholmen 1, PO box 1185, DK-2650 Hvidovre Denmark. 1993.
2) Saito H, Elting L, Bodey GP, Berkey P. (1989) Rev Infect Dis. 11: 912-920
3) Acar JF. (1986) Infect Control. 7: 273-278
4) Ball TK, Saurugger PN, Benedik MJ (1987) Gene. 57: 183-192
5) Eaves GN, Jeffries CD. (1963) J Bact. 85: 273-278
6) Nestle M, Roberts WK. (1969) J Biol Chem. 244: 5219-5225
7) Filimonova MN, Balaban NP, Sharipova FR, Leshchinskaya IB. (1980) Biokhimiya. 45: 2096-2103
Miller MD, Tanner J, Alpaugh M, Benedik M, Krause KL. (1994) Nat Struc Biol 1: 461-468
ageing population
A few days ago, I attended the 2009 meeting of the British Society for Research on Ageing (BSRA) in Manchester. It helps to reminded again of the current statistics:
—Of the current total world population of over 6.8 billion, there are over 750 million people aged 60 and over (11% of the total population).
—By 2050, the over-60 population is predicted to be just over 2 billion.
— By the end of the decade, there will be about 106 million people aged 80 or over. By 2050, this figure is projected to nearly quadruple to 395 million.
—By 2050, there are expected to be eight times as many people aged 100 and over as there will be in 2010.
—By 2050, there will be more people aged 60 and over than aged 14 or less.
—In China by 2050, there will be 438 million people aged 60 and over. Of those, 103 million will be 80 or older.
(source: UN World Population Prospects 2009)
Next time, I will write a lengthier account of the highlights from that meeting.
