Friday, November 18, 2005
You've got to love Ben Goldacre. On what seems like a one man mission to spread some understanding of how science works and how the public are led astray by poor science journalism and dodgy science used to make people rich. For sure, his tirade against humanities graduate is offensive to said BAs, but only if you fail to notice the partially cheek implanted tounge (only partially, since he has a point about those not qualified in the sciences irresposibly pontificating in the press, and how this can be dangerous, especially when it comes to peoples health, or their perception of their health).
Friday, October 28, 2005
The marriage of molecular genetics and traditional embryology has resulted in the field of modern developmental biology. In turn, developmental biology is being used to answer evolutionary question, much as comparative embryology was in the past. This is the exciting field of evo-devo (evolutionary developmental biology, you know how these crazy biologists love their snappy titles),
One of the coolest things I think that genetics has told us about evolution is the how many genes are preserved, both in form and functions, though out the taxa of modern mammals. A famous example, if not the most famous example, is that of the HOX genes as they are known in vertebrates, or Homeotic selector genes (HOM) in the fruit fly. These guys are found in a nested pattern along the anterior posterior length (think tail to head) of developing human, mice, frogs, fish, lamprey (ugly ‘primitive’ jawless fish), truncates and fruit fly. So basically the common ancestor of all vertebrates and all insects, apparently a “flattish round worm” that lived, ooo I duuno, ages ago (I really should look that up. Let’s say it was 500 million years ago, but I just made that up. Probably much further back.) had this ‘code’ that specified its arse from its head and kept it has not changed since, more or less.
The nested patter basically means that the domain of expression extends further from the tail to the head in some HOX genes than others. Different areas express a different compliment of of hox genes, and these different areas grown into different structures. The tail expressing more of the HOX genes that those nearer the head. In jawed vertebrates the head doesn’t express any hox genes.
If you use the evil powers possessed by the evil biologist you can extend the expression of the HOX genes more anteriorly. Similarly you can restrict the expression away form areas it is normally expressed. For example, in mice (an humans) the 1st branchial arch (BA1) does not express any HOX genes and develops into the jaw.The 2nd branchial arch (BA2) expresses HOX2A only and develops into the hyoid and other neck type things. Knocking HOX2A out of BA2 leads to it developing suspiciously jaw like structures, and knocking HOXA2 in to BA1 leads to it developing suspiciously hyoid like structures. Cool huh? You can do similar experiments to these in frogs, fish and fruit fly and get similar results, showing that these transcription factors do the same thing in all these diverse animals. I really think this is ace. Properly.
check this review.
Gaunt, S.J. 1994. Conservation in the Hox code during morphological evolution. International Journal of Developmental Biology 38:549-552
its old, but I’d give a load of papers, but that would involve looking them up, and I'm lazy.
Monday, September 19, 2005
Researchers in France have used mouse embryonic stem cells (ESTs) to repair the heart muscle of sheep, and in doing so shown that the stem cells of one species of mammal may possibly be used in future stem cell therapy of another (i.e, us lot) with out incuring the usual immune response problems what have dogged xenotransplantation research since such things were first thought of, which was ages ago. I'm sure I seem to remember that in the 1600 some Russian used a bit of a dogs skull to repair the skull of an arisotcrat. Or some such. That doesn't really sound credible does it? Oh well.
Basically stem cells are cells that can differentiate into any, or almost any, of the cell types in the body and so are known as totipotent (if they can form any cell type), or pluripotent (for those that can form many many cell types). Only the cells of the first few divisions of a zygote are truley totipotent, so most ESTs are pluripotent. ESTs don't seem to elicite an immune response, possibly due to fewer cell surface signalling molecules or some such, and so were selected to see it they could cross the species barrier.
Some sheeps were taken, some of which were immuno-repressed, and heart attacks indues, thus leaving scaring on the heart muscle. Murine ESTs were cultured with bone morphogenetic protein 2 (BMP2, one of the curses of my life) to make turn towards a cardiac fate, before being grafted on to the scar tissue of the the sheeps hearts. And you know what, it only boody worked. Well, kinda. And they only had 9 experimental animals, so don't do rushing out to get mice to help repair your heart attacks...
Claudine Mnard, Albert A Hagge, Onnik Agbulut, Marietta Barro, Miguel Cortes Morichetti, Camille Brasselet, Alain Bel, Emmanuel Messas, Alvine Bissery, Patrick Bruneval et al., Transplantation of cardiac-committed mouse embryonic stem cells to infarcted sheep myocardium: a preclinical study, The Lancet, Volume 366, Issue 9490, 17 September 2005-23 September 2005, Pages 1005-1012.
Thursday, September 08, 2005
Thankfully the sublimely anal Ben Goldacre's of "Bad Science" will not be leaving, though I'm not sure if Bad Science will carry on in its current guise. To tell the truth, I'm a little scared...
Monday, August 08, 2005
Last year, on Wednesday 15th of September 2004 to be exact, hurricane Ivan passed over wave-tide gauges used by the US Naval Research Laboratory (NRL) to measure these things The largest measured waves were to be around 27 meters, and the ones they missed reckoned to be 40 meters, or in surf-imperial, like, 132 feet dude. My lord. Surf's up.
 Science, Vol 309, Issue 5736, 896 , 5 August 2005
Wednesday, August 03, 2005
If you are of the former opinion and have ever tried to feed one of the smashers some jelly and ice cream, only to have the little get turn his nose up at you and then bring you a mouse for your three year old self to try and eat, you may be interested in knowing that new research indicates why cats, unlike most mammals, can not taste sweet stuff .
You may have read this in the papers as this is a rare old piece of research that can make genetics seem all cute and fluffy (kinda) instead of the evil monster that will turn us all in to rabid flesh eating zombies, a la Resident Evil.
Li et al found that the conserved gene for sweet receptors, Tas1r2 and 3 (TAS1R2 and 3 in humans, since we are special) are non-functional in domestic cats, where as they are all good and functional in sweet loving humans, rats, dogs and mice. There is a similar lack of sweet taste in the tigers and other felidae.
They also ask some interesting questions as to which came first, loss of sweets function in felidae or the exclusively carnivorous behavior.
Read it your self is you want more, I'm spent.
 Li X, Li W, Wang H, Cao J, Maehashi K, et al. (2005) Pseudogenization of a sweet-receptor gene accounts for catsÂ’ indifference toward sugar. PLoS Genet 1(1): e3. Full text online
Saturday, July 30, 2005
They got some volunteers to wear light-proof goggles and put a fibre optic cable in their mouth which shone light on to their retinas by making their whole head glow, while lying in an fMRI scanner. The fibre optic was to make sure that it was the blinking, rather than the lack of light, that made the brain do what it did. Whenever the volunteers blinked, brain activity in the visual cortex was suppressed.
So that's why you don't notice yourself blinking. Though I bet you're noticing it now you've read this eh?
1. Bristow D, Haynes JD, Sylvester R, Frith CD, Rees G: Blinking suppresses the neural response to unchanging retinal stimulation. Curr Biol. 2005 26;15(14):1296-300.
Little is known about giant squid - sightings have been few and far between. Early human sightings fostered myths of sea monsters (such as the Kraken) perhaps understably. They are the largest invertebrate at up to 18m (that's the length of a bendy bus), have the largest eye of the animal kingdom (25cm diameter) and weigh nearly a ton. No one really knows what they eat, as their stomach contents are usually pulverised to such a soup that no body parts can be recognised.
The cannibal squid in question was caught by fisherman and Deagle and his team analysed the DNA in the 'amorphous slurry' from the squid's gut. The DNA turned out to be that of A. dux (along with the blue grenadier fish). They also found among the slurry some pieces of giant squid tentacle and possible squid beaks.
They don't know however whether the tentacles belonged to a rival squid or whether they were this squid's own - like us biting our nails when nervous, giant squid have been known to chew off their own tentacles when stressed.
1. Deagle BE, Jarman SN, Pemberton D, Gales NJ: Genetic Screening for Prey in the Gut Contents from a Giant Squid (Architeuthis sp.). J Hered. 2005 96(4):417-23
Tuesday, July 19, 2005
Basically, the Chinese space programme is sending 50g of pig semen up on their next manned mission. Now i don't know off hand how much the average pig ejaculates, but I do know about human (again, off hand, as it were) and it's about 5ml. I'm assuming that semen is a little denser than water, so that's going to be no more than 10g at the very most, so 50g will be probably around 50ml, if not more. (That's a double). This will then be used to fertilise a female pig back on eart to study the effects of space travel on fertility and I suppose sperm storage....
Thursday, July 14, 2005
Those clever people at the University of Sheffield have recently
pubilished a paper in NeuroImage  to try and explain why auditory
verbal hallucinations, or voices in the head experienced commonly in
schizophrenia, are nearly always male.
Basically they played male, female and "gender ambiguous" voices to
male Sheffield uni students whist there brains were in a functional
magnetic resonance imaging (fMRI) machine and looked how the brain
reacted to each stimulus.
The long and short of their finding is that the male student brain (and
I suppose by inference the male bran in general) process male and
female voices in distinct ways. The female voice activates regions of a
brain specialising in "hearing" human voices (the right anterior
superior temporal gyrus, near the superior temporal sulcus), rather
than the general "minds ear" that the male brain activates. (the
mesio-parietal precuneus area). So this may explain why female voices
are more engaging to listen to. I'll let you insert your own quip
Does this mean that we, humans, have evolved to pay more attention to
female voices? Or just that males have evolved to pay more attention to
female voices? I suppose they'd have to do a similar set of fMRIs on an
equivalent female group.
Dilraj S. Sokhi, Michael D. Hunter, Iain D. Wilkinson and Peter W.R.
Woodruff, Male and female voices activate distinct regions in the male
brain, NeuroImage, In Press, Corrected Proof, Available online 22 June
Wednesday, July 13, 2005
No, not Science, the guy currently in channel 4's Big Brother 6 house. This is not a space to big him up. But perhaps we should since his very name is promoting the public awareness of science, especially amongst the brain dead who tune in to BB6 (I don't watch it, honest, though it is often on when I put the tv on, and I find myself looking and listening in the general direction of the box..........)
So, lets get going with the SCIENCE!!!!