麻豆淫院

Life on Earth possesses an exceptional ability to self-reproduce, which, even on a simple cellular level, is driven by complex biochemistry. But can self-reproduction exist in a biochemistry-free environment?

A by researchers from Harvard University demonstrated that the answer is yes.

The researchers designed a non-biochemical system in which synthetic cell-like structures form and self-reproduce by ejecting polymeric spores.

The PNAS paper reports a one-pot reaction in which chemically active polymer protocells began their journey as a uniform mixture of molecules that usually do not self-assemble. However, when placed under green light (530 nm), they formed vesicle-like structures that grew and divided as the reaction proceeded.

Living organisms produce offspring from their own cellular material, giving rise to new, independent life forms which interact with their environment to obtain food, energy, and information needed for survival. If all goes well, the internal chemical networks of these new systems also enable them to self-reproduce, leading to future generations. As Rudolf Virchow, father of cellular pathology, stated in 1858, "every cell comes from a pre-existing cell."

In biochemistry-based life, even single-celled organisms like bacteria depend on a chain of well-coordinated complex chemical processes to run the life-sustaining processes and reproduction.

It is known that biochemistry is sufficient for driving self-reproduction, but is it essential? Or can we build artificial, compartmentalized chemical systems in the lab that can self-assemble and reproduce on their own?

Previous studies have shown reproduction-like behaviors such as polymerization-induced self-assembly (PISA) in micelles and vesicles. However, these processes were neither biochemistry-free nor did they demonstrate true autonomous self-reproduction.

To explore the unknown, the team designed a one-pot PISA batch reactor consisting of strictly non-biochemical molecules with an aim to synthesize amphiphiles that can self-organize, self-assemble, and self-initiate into chemically active entities.

The reaction vial included an aqueous solution of a hydrophilic polymer with a hydrophobic chain transfer agent molecule (CTA) attached to its end, along with the monomer to be polymerized and a photocatalyst in a nitrogen-filled inert environment. This mixture was then allowed to sit under green LED light for 90 minutes at 33掳C.

They observed that the mixture of chemicals undergoes photo-Reversible Addition-Fragmentation Chain Transfer (RAFT) photopolymerization in water to transform the starting molecules into amphiphilic block copolymers. These block copolymers then gave rise to non-biochemical polymer vesicles or synthetic cells that displayed self-reproduction behavior via PISA.

The vesicles not only formed and sustained themselves but also released polymeric "spores" that seeded a nonlinear, exponential increase in vesicle numbers, with each new generation inheriting certain properties from their "parent" vesicles.

The behavior shown in this study mimics self-reproduction鈥攁 key feature of living systems鈥攁rising from simple chemistry without the need for complex biochemical processes.

The researchers note that the findings not only offer insights into how life might have begun but also open new possibilities for creating a wide range of abiotic, life-like systems.

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