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Clay's matchmaking 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 Szostak.

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 chains.

Computer games can treat phobias
Computer 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.

Exposure therapy

"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 Behaviour.

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 patient.

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 Frog that 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
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.

Full Article At Nature
Drought Resistant Plants
drought resistant plants

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 @Africa


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