“One human chimera came to light when
a 52-year-old woman demanded an explanation from doctors after tests
showed that two of her three grown-up sons were biologically unrelated
to her.
“Although the woman, "Jane", conceived them naturally
with her husband, tests to see if she could donate a kidney suggested
that somehow she had given birth to somebody else's children.”
“In medicine, a person composed
of two genetically distinct types of cells. Human chimeras were first discovered
with the advent of blood typing when it was found that some people had more
than one blood type. Most of them proved to be "blood chimeras"
-- non-identical twins who shared a blood supply in the uterus. Those who
were not twins are thought to have blood cells from a twin that died early
in gestation. Twin embryos often share a blood supply in the placenta, allowing
blood stem cells to pass from one and settle in the bone marrow of the other.
About 8% of non-identical twin pairs are chimeras.” [Quoted from medterms.com]
In Greek mythology, the Chimera
is fire-breathing female monster with a lion’s head, a goat’s
body and a serpent’s tail. Its parents were Typhon and Echidna.
In due course, the Chimera was killed by Bellerophon, a Corinthian hero.
programming biological reactions, like programming computers
We can program [tell] computers to do huge calculations,
we can make word processors follow series of instructions, now researchers
are starting to make biological processes act according to instructions.
In this case, some DNA tells other DNA to ‘walk’ along a DNA
track.
“[...] long-term vision of developing a "compiler
for biomolecular function" that takes as input a modular conceptual
device design and provides as output a list of biomolecules that interact
to implement the desired function.” [Quoted from The
Pierce Lab]
“Ultimately, the development of an efficient catalytic DNA fuel
delivery mechanism should enable the rational design of a completely
artificial DNA walker that locomotes autonomously, allowing detailed
programming of a motor protein mimic.” [Quoted from The
Pierce Lab]
Right: “The diagrams depict (a) unbound walker, (b) walker attached
to branch 1, (c) walker attached to branches 1 and 2, and (d) walker released
from branch 1 to yield duplex waste.”
For those who are interested to a greater degree, here
follows the detailed description of this walking process (note that the
description is in science-speak).
“The system has four components (Table 1,
which lists the DNA sequences used): a walker (W), a track (T),
attachment fuel strands (A), and detachment fuel strands (D).
“The walker consists of two partially complementary oligonucleotides,
with a 20-bp helix joining two single-stranded legs (each 23 bases).
“The track, constructed of six oligonucleotides, has four protruding
single-stranded branches (each 20 bases) separated by 15-bp scaffold
helices.
“Neighboring branches run in opposite directions, so spacing
of 1.5 helical turns places all branches on the same side of the track
approximately 5 nm apart [see diagram above].
“[As seen in the diagram], the walker strides along the track
under the external control of A [attachment]
and D [detachment] strands. An A strand specifically
anchors the walker to a branch by forming helices with the corresponding
leg (18-bp) and branch (17-bp).
“Single-stranded hinges adjacent to either end of these helices
(underlined in Table 1) provide flexibility for adopting different conformations
depending on the fuel species that are present. When both legs are bound
to the track [ c) in the diagram], the
trailing leg is released using a D strand that nucleates with the perfectly
complementary A strand at a 10-base overhang and then undergoes a strand
displacement reaction to produce duplex waste and free the walker leg
for the next step [ d) in the diagram].”
end notes
compiler
A compiler takes a program written in a higher level language and turns it into
a series of machine code instructions.
A common form of modern analysis is to take large numbers
of papers, whittle them down to the most promising - a typical area
being where there is replication of studies - and analyse them statistically to seek
correlations of results. Below are extracts from such a study that started with more
than 1000 papers.
“The team, led by Liping Wei, surveyed scientific literature
published in the past 30 years and collected 2,343 items of evidence
linking genes and chromosome regions to addiction based on single-gene
strategies, microarray, proteomics, or genetic studies. They made this
gene atlas freely available in the first online molecular database for
addiction, named KARG,
with extensive annotations and friendly web interface.”
“She found 18 [genes] that were involved in addiction to at
least one type of drug. Five, however, were common to all four types,
and these five pathways therefore look as though they are at the core
of the process of addiction. Three of the five were already under suspicion.
Dr Wei's result provided strong statistical evidence to back up what
had just been hunches. Two other pathways, however, had not previously
been considered as being involved in addiction.
“The existence of these five central pathways helps explain a
lot about addiction. First, it gives weight to the belief that some
people are more susceptible to all sorts of addiction than others are.
That contrasts with the thought that addictions are substance-by-substance
phenomena, though the two ideas are not mutually exclusive since changes
in the 13 substance-specific pathways clearly also result in addiction.
“Second, the particular pathways involved help to explain why
addiction is so hard to reverse. Several of them take part in strengthening
the connections between nerve cells, which is the underlying basis of
learning. Unlearning something by breaking these connections is hard.
“Third, Dr Wei was able to link the five central pathways together
into a network, and show that this network has four positive-feedback
loops in it. Work on other species in other contexts suggests that the
mixture of loops she found was one that often results in rapid and irreversible
biological processes - which is exactly what is seen in addiction.”
“Bill Gates and ex-Microsoft executive Charles Simonyi have donated
a combined $30 million to the Large
Synoptic Survey Telescope, which will feature the largest digital
camera ever constructed. Scientists say it will provide a "color
movie" of the universe.”
—
“The telescope is to be built on 9,000-foot Cerro Pachon in northern
Chile. It will take an image every 15 seconds nightly, and its camera
- the world’s largest and most powerful digital device - will
read out the image in 2 seconds.
“There are lots of things that happen every night in the sky,
and no one has been able to track them and detect them," Sweeney
said.
“With the telescope operating, he said, scientists will be able
to quickly find Earth-threatening asteroids and supernovae, and will
be able to map out 100 billion galaxies.”
Large Synoptic Survey Telescope on Cerro Pachon,
northern Chile [Artist’s impression]. Image: Michael Mullen Design, LSST Corporation
“Google, the world's largest Internet search engine, has joined
a group of nineteen universities, national labs and private foundations
that is building the Large Synoptic Survey Telescope (LSST).”
[Quoted from wired.com]
Come
to Denmark. There, a kind of large blue butterfly ensure that their caterpillars
smell like ant larvae, so the ants will taken the caterpillars home and
feed them. When the ants catch on, change the smell of their larvae and
start ignoring the caterpillars, the butterflies go and parasite on a
different, closy related, ant species.
[David Nash:]
“The caterpillars first start developing on a food plant, but
after they reach a certain stage they leave the food plant and wait
on the ground to be discovered by these ants, and they mimic the surface
chemicals that the ants have on their own brood. So again, they’re
producing a signal which says, I’m an ant brood. And we’ve
been able to show that the closer that mimicry is, the faster they are
picked up by ants and taken back into the ant nest and put amongst the
brood. And once they’re there amongst the ant’s own brood,
they become highly virulent parasites; they eat some of the brood, and
they will also get fed by the worker ants, and they’ll get fed
in preference than the ant’s own brood.”
—
“ [...] we think in some areas the butterfly can actually suppress
that ant colony so much that it becomes very rare and is no longer worth
exploiting for the butterfly, and then it tends to use the other ant
species as a refuge while that other species recovers. One way you can
put it is, if we have one species where the ant is exploited at a relatively
constant rate, and we have another species which, when it’s common,
is exploited even more than you would expect, but when it’s rare
it’s hardly exploited at all.”
Where neighbouring ant colonies are closely related genetically, David
Nash and his colleagues found the ants to be changing their surface chemistry,
and so the way they and their larvae smell, in response to the parasitism
by the butterflies, and in some cases, they seem to be avoiding parasitism
that way.
The above is excerpts from the transcript of
a Science and AAAS [American Association for the Advancement
of Science]podcast
interview [MP3 format]. The interview is the
first item after the intial fluff and self-advertising.
The serious content of this seven-part video lecture
series is an introduction to risk management (there
are 82 videos listed, most of which are just under 10 minutes). The
series, given by Greg Craven [also known as wonderingmind42], is applied to AGW, but that is not the prime value of the talks.
And here is a short version for those who don’t
want a headache, and who also have faith! This video has been watched
several million times and is available in many copies. It has only been
on the web less than a year single-part
version.
This
news item has been ‘promoted’ to its own page - 
![Large Synoptic Survey Telescope on Cerro Pachon, northern Chile [Artist’s impression].Image: Michael Mullen Design, LSST Corporation](/images/4news11/telescope_dome_cerro_pachon.jpg "Large Synoptic Survey Telescope on Cerro Pachon, northern Chile [Artist’s impression].Image: Michael Mullen Design, LSST Corporation")
“ [...] we think in some areas the butterfly can actually suppress
that ant colony so much that it becomes very rare and is no longer worth
exploiting for the butterfly, and then it tends to use the other ant
species as a refuge while that other species recovers. One way you can
put it is, if we have one species where the ant is exploited at a relatively
constant rate, and we have another species which, when it’s common,
is exploited even more than you would expect, but when it’s rare
it’s hardly exploited at all.”