Life is weak to radiation, could we become something more than biological? What if we were made from Iron or Silicon, or Nitrogen?

When it comes down to it what on earth or anywhere else is “life”? From our perspective rocks, spoons, and slippes are all inanimate objects. But how do we decide what is alive and what is not? Is there a point where the chemistry sudddenly crosses over? Would we recognize an alien species if we saw it? And if you believe hard enough can you bring something to life? When you’re trying to define life, you realize it can’t be black and white. Its like asking ow man trees do you need to make a forest, when is a snack equal to a meal. There is no oine criteria we can use to define life, we have an obvious tendancy to focus on our planetary carbon-based existence when there are actually countless other worlds that could have created living beings form any other elements, such as silicon or Iron. So if we accept that life is a very grey area, then we must focus on key facets to determine if something really is alive. Firstly, complexity. Life needs to practice homeostasis, an equilibrium for it’s internal conditions, temperature, ph value, glucose levels, etc. So what about life on earth? What piece of chemical creativity created the winding path from molecule to monkey to mammal?

Let’s have a quick wonder into the hypothetical. We’re made of carbon, but what other kinds of elements could create life and what conditions would they need to exist? Silicon is probably the most likely candidate since it can create molecules that are large enough to carry the massive amount of information that you need to encode a life form. What more we have a hint at it’s existence on earth, a type of algae called diatoms have a cell wall made of silicon. V adam N seesovich has proposed a possible space born life form in the form of dust suspended in plasma. In certain extraterrestrial conditions, the dust could self organize into complicated structures, and from there, who knows what the dust could evolve into. All in all, you are unbelievably lucky to be alive. It’s not just a particular combination of genes, but also the overwhelming amount of chance and good fortune that got us from little dots in molecular soup, to walking talking land mammals.

Could living rocks exist? Somewhere out there in the universe there might be creatures so different from us that we wouldn’t even recognize them as alive. All living things that we know about have some basic things in common, they grow, reproduce, respond to stimuli in their environement, and evolve over time. They share the same basic biochemistry, they’re made of long chains of carbon molecules that hang out in a water based medium. But it’s also possible there’s life that’s not carbon based, and that life would be a lot different than what we’re used to. Carbon’s abiliuty to form long chains makes it the perfect base for building molcules complex enough to keep a living thing alive. But even though carbon is great for building these big complex molecules, it’s not the only element that can do this, which is just under carbon in the perriodic table is in the same elemental group chalcogens, shares many of the same chemical properties. Just like carbon, the outer layer of a silicon atom has 4 unpaired aelectrons ready to form molecule building bonds. It can also form long chains and bond to oxygen, just like carbon. But a lot of the bonds formed by silicon arer weaker than those formed by carbon, especially the silicon-silicon bonds it would need to make long chains, and even when Silicon-Silicon bonds do form they’re generally unstable if there’s oxygen around. Still because they have sop much in common, some scientists think that silicon based life could theoretically be possible, even though we’ve never found any. Like carbon based life, silicon based life would grow, reproduce, respond to stimuli, and evolve over time. But we might not even recognize it as life at first. A silicon life form might look a lot more like a pile of rockls than a plant or animal, and would probably do some pretty weird things. When silicon reacts to oxygen for example, it turns into quartz, so silicon based organisms that breath oxygen would exhale quartz. The silicon based bonds are most stable at high temperatures so if silicon based life does exist, the best place to look for it would be very hot places, like deep beneath the planet’s surface. But silicon based life probably wouldn’t be very complex because of ts unstable bonds. Still sci fi writers had a lot of fun with this idea, like the star trek originaal’s silicon based creatures. But organisms with such different biochemistry might be hard to even detect. They might look more like rocks or crystals than anythiong we’d recognize as alive. some scientists have proposed the idea that there could be a so called shadow biosphere of non-carbon based life living right here beside us on earth. After all, silicon is the 2nd most common element in the earth’s crust after oxygen, but that silicon is bound up in rocks where it would be hard for organisms to incorporate it into their biochemistry. If silicon-based life does exxist on earth, it might be in the form of silicon based life forms living in magma deep inside the earths mantel, but no one has found any actual evidence of this. Some scientists are working on making their own version of silicon nbased live or at least the first steps toward it. In march caltech scientists announced that they had found a species of thermophillic bacteria, bacteria that thrive in extrreme heat, with an enzyme that in very rare cases incorporated silicon based molecules into it’s carbon based molecules, a sort of chemical accident. Using artificial selection they were able to modify the bacteria ina lab to produce the molecules with silicon in the 2000 times as often. Someday artificially created makeups like this may be able to produce complex silicon molecules that chemical molecules that chemical companies can turn into glues and sealants. Even better, research like this also helps scientists understand more about how life can use silicon

SCIENTISTS CREATE SILICON-BASED LIFE

Despite the fact that silicon makes up about 30 percent of the Earth’s crust, it plays no role in the creation of organic life, and no known organisms are able to incorporate it into the carbon chains that make up their biological material. However, after performing a little genetic trickery, scientists have finally got living cells to bind silicon and carbon together, creating new opportunities for industrial and pharmaceutical production.

Silicon-containing compounds have a range of applications, and are used to create industrial catalysts, superconductors, and medicinal products. However, creating these materials can be costly and often requires the use of highly expensive trace metals.

Researchers from the California Institute of Technology therefore decided to seek out alternative methods of producing these materials, turning to nature for inspiration. First, they sifted through databases in search of organic enzymes that are capable of catalyzing silicon, and identified an iron-based enzyme that helps to bind silicon with hydrogen in a bacteria called Rhodothermus marinus, found in underwater hot springs.

They then synthesized the gene for this protein and inserted it into E.coli cells, which caused the bacteria to bind silicon and carbon when fed certain silicon-containing ingredients. However, reporting their findings in the journal Science, the study authors write that the efficiency of this catalyst was not particularly impressive.

They therefore tweaked the enzyme’s genetic code slightly, adding in a few mutations that they suspected would create an active site to catalyze silicon-carbon binding. Lo and behold, their suspicions turned out to be accurate, as the altered protein was able to bind the two elements with superb efficiency, producing a yield 15 times higher than that of the most advanced industrial catalysts.

In their write-up, the researchers claim their findings “affirm the notion that nature’s protein repertoire is highly evolvable and poised for adaptation,” adding that “with only a few mutations, existing proteins can be repurposed to efficiently forge chemical bonds not found in biology and grant access to areas of chemical space that living systems have not explored.”

Despite the fact that silicon makes up about 30 percent of the Earth’s crust, it plays no role in the creation of organic life, and no known organisms are able to incorporate it into the carbon chains that make up their biological material. However, after performing a little genetic trickery, scientists have finally got living cells to bind silicon and carbon together, creating new opportunities for industrial and pharmaceutical production.

Silicon-containing compounds have a range of applications, and are used to create industrial catalysts, superconductors, and medicinal products. However, creating these materials can be costly and often requires the use of highly expensive trace metals.

Researchers from the California Institute of Technology therefore decided to seek out alternative methods of producing these materials, turning to nature for inspiration. First, they sifted through databases in search of organic enzymes that are capable of catalyzing silicon, and identified an iron-based enzyme that helps to bind silicon with hydrogen in a bacteria called Rhodothermus marinus, found in underwater hot springs.

They then synthesized the gene for this protein and inserted it into E.coli cells, which caused the bacteria to bind silicon and carbon when fed certain silicon-containing ingredients. However, reporting their findings in the journal Science, the study authors write that the efficiency of this catalyst was not particularly impressive.

They therefore tweaked the enzyme’s genetic code slightly, adding in a few mutations that they suspected would create an active site to catalyze silicon-carbon binding. Lo and behold, their suspicions turned out to be accurate, as the altered protein was able to bind the two elements with superb efficiency, producing a yield 15 times higher than that of the most advanced industrial catalysts.

In their write-up, the researchers claim their findings “affirm the notion that nature’s protein repertoire is highly evolvable and poised for adaptation,” adding that “with only a few mutations, existing proteins can be repurposed to efficiently forge chemical bonds not found in biology and grant access to areas of chemical space that living systems have not explored.”

 

 

 

6a00d8341bf7f753ef0147e054b9f4970b-600wi.jpg

 

Advertisements