could have sparked life
Two of the crucial components for
the origin of life - genetic material and cell membranes
- could have been introduced to one another by a lump of
clay, new experiments have shown.
The study of montmorillonite clay, by Martin Hanczyc, Shelly
Fujikawa and Jack Szostak at the Massachusetts General Hospital
in Boston, revealed it can sharply accelerate the formation
of membranous fluid-filled sacs.
These vesicles also grow and undergo a simple form of division,
giving them the properties of primitive cells. Previous
work has shown that the same simple mineral can help assemble
the genetic material RNA from simpler chemicals. "Interestingly,
the clay also gets internalised in the vesicles," says
Leslie Orgel, an origin of life expert at the Salk Institute
for Biological Sciences in San Diego, California. "So
this work is quite nice in that it finds a connection between
the mechanism that creates RNA and encloses it in a membrane."
The genesis of genetic material and the emergence of cell
structure are hot areas of research, but until now the two
had not connected. The birth of genetic material was clearly
crucial for life to take on its unique abilities to inherit,
mutate and evolve.
And membranes were key to the physiology of cells because
they protect their contents, concentrate chemicals to promote
reactions and isolate successful genes from unsuccessful
ones. "It's clear you really need both these elements
to get evolution off the ground and running," says
Research has already shown that some of building blocks
for RNA-like molecules and membranes are spontaneously created
by chemical reactions in outer space and in conditions that
may have existed on the primordial Earth. But how these
subunits were then assembled is still debated.
For RNA, one popular theory revolves around the unusual
properties of montmorillonite clay. The negatively charged
layers of its crystals create a sandwich of positive charge
between them. This turns out to be a highly attractive environment
for RNA subunits to concentrate and join together into long
games can treat phobias
Popular computer games like Half-Life and Unreal Tournament
could provide a cheap and effective treatment for people
with debilitating phobias, say Canadian computer scientists.
Specially made virtual reality (VR) equipment is already
used to treat certain types of phobia. Exposing patients
to the source of their pathological fear within this controlled
and safe environment can be an effective therapy.
But Patrice Renaud and colleagues at the University of
Quebec in Canada took the simpler approach of customising
existing games to create VR worlds for a range of phobias.
Tests with phobic patients showed that the games stimulated
a response that could be used to perform controlled treatment.
The researchers suggest that computer games might, therefore,
be a cheap and easy-to-use form of VR treatment. The whole
cost of the software and hardware comes to a few hundred
dollars rather than many thousands, they say. The games
also provide highly realistic graphics and can be easily
adapted to an individual patient's particular fears.
"The effectiveness of the inexpensive hardware and
software used in this study shows that VR technology is
sufficiently advanced for VR exposure therapy to move into
the clinical mainstream," they write in a paper published
in the October edition of the journal CyberPsychology and
Games often have software tools that players can use to
build new levels or custom tournaments. The researchers
used these to construct their phobia-fighting virtual environments.
Off-the-shelf head-mounted displays and head-tracking sensors
were used to create a more immersive experience for each
Within Half-Life, scenes containing various different
types of spider were built to treat people with arachnophobia.
Unreal Tournament was used to make environments for those
with a fear of heights or confined spaces.
"Treating claustrophobia this way is most interesting,"
says Anthony Speed, a researcher specialising virtual reality
phobia therapies at University College London. He says others
have shown that it is relatively simple to treat a fear
of heights and spiders using a VR approach, but more costly
and complex walk-in virtual reality equipment is normally
needed to treat a fear of confined spaces.
|New frog family
points to India's past
Scientists have reported the discovery of a new species
of frog with unusually deep evolutionary roots in the Western
Ghats of southern India.
An article reflects on the implications of the discovery
of the species – which merits the establishment of
a new taxonomic family – for models of continental
drift of India.
The frog's closest relatives are the so-called sooglossids,
a small group of frogs found only in the Seychelles in the
Indian Ocean. Although now separated by 3,000 kilometres
of ocean, the Seychelles and India once formed part of a
greater landmass that split up millions of years ago.
The discovery of a living coelacanth in 1938 captured public
attention because it represented an ancient lineage of fishes
thought to have been extinct for some 80 million years.
Biologists are racing to survey and discover species in
hot spots before they disappear. Unfortunately, fieldwork
can be dangerous (diseases, guerrilla wars, venomous animals),
and greater efforts are now required to reach unaltered
habitats, such as the tops of mountains. Moreover, some
governments are afraid
Article At Nature
of losing their countries' genetic resources, and have been
discouraging foreign scientists from collecting plants and
animals. To complete a gloomy picture, taxonomy in general
has become an unpopular career choice. Nonetheless, extraordinary
discoveries such as this frog show that there is an urgent
need for more biotic surveys.
A type of resurrection plant, Xerophyta viscosa Baker is
an unusual (and very tough) plant. Xerophyta viscosa is
particular to Africa and is found in mountain top habitats
such as Cathedral Peak in the Drakensberg mountains, which
stretch across Lesotho and South Africa.
This plant has many medicinal applications. The species
of resurrection plant known in Zulu as 'isiphemba' or 'isiqumama'
(Xerophyta retinervis) is used for asthma treatment, nose
bleeds, general aches and as an anti-inflammatory. The active
ingredient, called amentoflavone, is also found in gingko
extract. But there is a critically important aspect to these
resurrection plants which has nothing to do with medicine
and has another branch of science very, very interested.
What is so unique about X. viscosa amongst the higher plants,
is that it is able to survive long periods without water.
When it rains again, the plants rehydrate completely and
remarkably resume their full metabolic functions within
24 to72 hours, depending on the species (1).
Imagine if other plants, in particular crop plants, were
capable of this? To the average farmer or small crop grower
living in drought-prone regions this may seem a little far-fetched.
Scientists say that this may in fact be achievable. The
secret is in the genes. X. viscosa's ability to survive
extremes of temperature, high winds and lack of water that
would see other plants perish, is in fact genetically coded.
Full Article At Science