#protocells

The cells that make up all living things, despite their endless variations, contain three fundamental elements. There are molecules that encode information and can be copied—DNA and its simpler relative, RNA. There are proteins—workhorse molecules that perform important tasks. And encapsulating them all, there’s a membrane made from fatty acids. Go back far enough in time, before animals and plants and even bacteria existed, and you’d find that the precursor of all life—what scientists call a “protocell”—likely had this same trinity of parts: RNA and proteins, in a membrane. As the physicist Freeman Dyson once said, “Life began with little bags of garbage.”

The bags—the membranes—were crucial. Without something to corral the other molecules, they would all just float away, diffusing into the world and achieving nothing. By concentrating them, membranes transformed an inanimate world of disordered chemicals into one teeming with redwoods and redstarts, elephants and E. coli, humans and hagfish. Life, at its core, is about creating compartments. And that’s much easier and much harder than it might seem.

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Scientists Identify Molecule That Could Have Helped Cells Survive—and Thrive—on Early Earth

To truly understand how the body works and improve human health, researchers need to tease apart the building blocks of our cells. But as scientists continue to make major breakthroughs in cellular biology, an important question lingers: How did cells originally form billions of years ago?

A new study, led by Ramanarayanan Krishnamurthy, PhD, of Scripps Research, and Sheref Mansy, PhD, of the…

アート＋ウェットな人工生命：今日、科学や工学をはじめとするさまざまな技術の進歩により、プロトセルや自走性油滴、化学システムとロボットのハイブリッドといった、「生命らしさ」をつくる技術が加速している。この進歩には、アーティストも高く注目し、芸術のための新たな素材としての可能性に挑戦し、多様なビジョンを構築している。このワークショップでは、「プロトセル」の世界的な権威であるラスムッセン教授を迎え、教授による基調講演と、ハンズオン形式の実践という2つの軸で構成されている。理論と実践が融合した全体を通じて、以下の2つのテーマを探求する。①21世紀のアートとウェットな人工生命の関係について知り、新たな視点を得、人工生命に近く最もシンプルなモデルであるプロトセルについて実践を通じ理解を深める。②生命らしいウェットな人工生命をつくる技術にともなって生まれる美学や哲学、倫理性などの課題について、アートに期待される使命や可能性を議論する。

企画：Juan M. Castro and Akihiro Kubota 　　　　

主催 ：東京大学大学院総合文化研究科　　　　

New Post has been published on http://www.newsnish.com/technology/science/protocells-show-ability-to-reproduce/

‘Protocells’ Show Ability to Reproduce

Man-made balls of genetic material and membranes can pull off a decent impression of primitive cells.

These squishy spheres known as “protocells” can accept chemical deliveries to sustain a division process that mimics that of living cells, researchers in Japan report September 29 in Nature Communications. These cell-like creations may be a step toward making future protocells that can imitate evolution, the scientists say.

The results offer clues to how living cells developed their ability to reproduce, says study coauthor Tadashi Sugawara, a physical organic chemist at Kanagawa University in Japan. Like the cells within plants and animals, these protocells have four stages in their division process, Sugawara says.

The real living cells and the protocells both have a replication stage and division stage. But instead of two growth phases, these protocells have an “ingestion” stage, in which they take in substances from their surroundings, and a “maturity” stage.

The protocells, composed of thin membranes wrapped around DNA and proteins, can expand and divide when provided with a membrane-building molecule. But new protocells quickly run out of other biochemical ingredients needed to continue reproducing. So the researchers designed membrane-wrapped delivery vessels that provide daughter protocells with additional biological building blocks. With these ingredients, the protocells can continue dividing for a third generation.

These protocells appear to require a complex design to work properly, says evolutionary biologist David Baum of the University of Wisconsin–Madison. Plus, some scientists believe cell precursors like these may not have been the first living things to undergo evolution, he says. Chemical oozes may have been able to cooperate with each other and grow more sophisticated over time, before a cell’s ancestors developed, he says.

Baum notes that the protocells in the study aren’t self-sustaining, as the researchers must replenish the system with essential chemical ingredients. The protocells also depend on fluctuations in heat and acidity to copy their genetic material and accept chemical deliveries, which makes them too artificial to be sustainable, Sugawara says. But he notes that hot, acidic environments like those around hydrothermal vents could have driven similar genetic processes in nature.

Good imitators of early cells could help scientists understand how real cells evolved, he adds. “If we could make many instances where we could get evolving protocells, and we could see what you need, that would really help us understand how that could have arisen naturally.”