'Artificial Life' Comes a Step Closer?

[bomohwkl]

http://news.bbc.co.uk/1/hi/sci/tech/4104483.stm

Researchers at Rockefeller University in the US have made the first tentative steps towards creating a form of artificial life.

Their creations, small synthetic vesicles that can process (express) genes, resemble a crude kind of biological cell.

The parts for their "vesicle bioreactors", as they call them, all come from diverse realms of life.

The soft cell walls are made of fat molecules taken from egg white. The cell contents are an extract of the common gut bug E. coli, stripped of all its genetic material.

This essence of life contains ready-made much of the biological machinery needed to make proteins; the researchers also added an enzyme from a virus to allow the vesicle to translate DNA code.

When they added genes, the cell fluid started to make proteins, just like a normal cell would.

Jelly fish

A gene for green fluorescent protein taken from a species of jellyfish was the first they tried. The glow from the protein showed that the genes were being transcribed.

With a second gene, from the bacterium Staphylococcus aureus, the researchers got their cells to make small pores in their walls.


Some bacteria can survive with just a few hundred genes
These let nutrients in from the surrounding "soup", so that the cells could function, in some instances, for several days.

Albert Libchaber, who heads the project, stresses that these bioreactors are not alive - they're performing simple chemical reactions that can also happen in cell-free biological fluids.

But the research is one strand in a new field called synthetic biology, where the aim is to re-design entire organisms, or recreate them from scratch.

The bio-entrepreneur Craig Venter, who headed the commercial venture to decode the human genome, is currently trying to strip a bacterium down to the minimum set of genes needed for survival.

Synthetic virus

Two years ago, another team showed that polio viruses could assemble themselves from off-the-shelf chemical components mixed in a test-tube.

And several chemists are exploring the kinds of chemical reactions that may have preceded life.

Albert Libchaber's hope is to build up towards a minimal synthetic organism, with a designed cell wall, and a mixture of gene circuits that would let it maintain itself like a living cell.

As these constructs become more lifelike, the rest of us will have to start rethinking the nature of life.

"This is rather philosophical," says Dr Libchaber.

"For me, life is just like a machine - a machine with a computer program. There's no more to it than that. But not everyone shares this point of view," he told the BBC.

He also stresses that there is no danger in the experiments. Not only are his cells artificial, they can function only in the nutrient medium he supplies them.

He said: "If you take our system out of its environment, it just doesn't function."

Details of Libchaber's work with Vincent Noireaux have been published by the journal Proceedings of the National Academy of Sciences.

[Vesko]

Difficulty in building life: scientists have incorrectly lead the general public to believe that by the knowledge of the building structures and the genome of an organism, we could build the organism. There's one little secret that I've learned recently from the book "Human Devolution": we do not know how genes result in the formation of the complex biological structures. Genes do not reveal how those structures are formed. To us, they are like switches for a black box. Could it be that the information (blueprint) for the formation of complex biological structures is not, or not entirely, in the physical body?

[Vesko]

Here's more on what I wrote above about why understanding of genes is not enough:

The world-famous biologist Rupert Sheldrake from the 2005 "Edge Annual Question": http://www.edge.org/q2005/q05_easyprint.html:

Over the course of fifteen years of research on plant development, I came to the conclusion that for understanding the development of plants, their morphogenesis, genes and gene products are not enough. Morphogenesis also depends on organizing fields. The same arguments apply to the development of animals. Since the 1920s many developmental biologists have proposed that biological organization depends on fields, variously called biological fields, or developmental fields, or positional fields, or morphogenetic fields.

All cells come from other cells, and all cells inherit fields of organization. Genes are part of this organization. They play an essential role. But they do not explain the organization itself. Why not?

Thanks to molecular biology, we know what genes do. They enable organisms to make particular proteins. Other genes are involved in the control of protein synthesis. Identifiable genes are switched on and particular proteins made at the beginning of new developmental processes. Some of these developmental switch genes, like the Hox genes in fruit flies, worms, fish and mammals, are very similar. In evolutionary terms, they are highly conserved. But switching on genes such as these cannot in itself determine form, otherwise fruit flies would not look different from us.

Many organisms live as free cells, including many yeasts, bacteria and amoebas. Some form complex mineral skeletons, as in diatoms and radiolarians, spectacularly pictured in the nineteenth century by Ernst Haeckel. Just making the right proteins at the right times cannot explain such structures without many other forces coming into play, including the organizing activity of cell membranes and microtubules.

Most developmental biologists accept the need for a holistic or integrative conception of living organization. Otherwise biology will go on floundering, even drowning, in oceans of data, as yet more genomes are sequenced, genes are cloned and proteins are characterized.