Immunity by Incompatibility — Chiral Humans
By Jarek Duda, PhD
A fascinating cellular engineering concept to ensure perfect infection-free life
Arthur C. Clarke writes about a molecular mirror-image human being starving to death because his body cannot process normal sugars (see “Technical Error” in Clarke's book "The Collected Stories").
Jarek Duda takes this idea further, and shows us how we can prevent virtually ANY microbe (virus, bacterium, fungus, protozoan, etc) from infecting us — by constructing mirror-image (chiral) human beings which will be totally incompatible to these microbes!
Reconstructing ourselves in chiral form, using the mirror-image reflection of our cellular components is achieved by replacing left-handed amino acids with right-handed ones, in order to create mirror reflections of all human proteins.
Analogically, we could get chiral sugars, DNA, etc, on which reflected enzymes would work perfectly. Finally we would get a normally functioning molecular mirror reflection of a natural organism – a chiral counterpart organism – with which natural viruses and bacteria couldn’t interact. Electromagnetic force (chemistry) is unchanged under such molecular reflection transformation (P-symmetry). There is a small alteration of weak interactions under reflection, which can produce very small corrections, but these corrections are many orders of magnitude lower than thermal noise – almost certainly too tiny to alter any biochemistry.
Life on Earth only uses left-handed amino acids. All of biology has this homochirality. Chiral (right-handed) amino acids do not exist in nature, so any such chiral organism would be entering completely virgin territory, biologically speaking.
Such a chiral organism would obviously need to be feed with chiral food, produced by chiral plants. The great advantage, though, is that such chiral organisms would enjoy a disease-free life, completely immune to all viruses and microbes. And we would eliminate plagues and epidemics.
Viruses would be completely incompatible with the reflected human cellular structures; and bacteria, protozoa and fungi could not function because they would not be able to find normal sugars inside reflected organisms. The reverse sugars circulating in the chiral human body would be indigestible as far as normal bacteria are concerned, so any bacterium entering a chiral human would simply starve to death. The chiral environment is absolutely hostile for normal viruses, protozoa, bacteria, etc.
In order to infect a chiral human, existing bacteria would have to evolve their own mirror image structure from scratch. This is extremely unlikely to happen (since DNA holds the genes, the alphabet of evolution, but DNA itself is a priori to genes, and therefore more or less untouched by the process of evolution). Terrorist acts, however, are a concern. In the case of sabotage, we would have to control the spread of any terrorist-engineered chiral virus using the anti-terrorist and anti-biowarfare measures that we already have in place today.
How do we create a chiral organism, such as a reflected human? The synthesis of every molecule, a reflected zygote is difficult, because we don’t have chiral enzymes. But the real problem is creating the correct structure of membranes with specific concentrations. Nevertheless, with advancing nano-engineering, this could be possible in say 50 years, when we could slowly transform our ecosystems, starting from the bacterium E. coli, which will act as our factory, and later plants. Finally, if all goes well, the human being.
But in such a sterile environment, would we have perfect health? Perhaps the stresses created by small infections can, like small amounts of radiation, have positive long-term influence? For example, infection helps to get rid of damaged and weak cells in an organism. And the hygiene hypothesis states that the actual absence of exposure to microbes can lead to autoimmune diseases (although more probably, autoimmune diseases are due to chronic underlying infection from viruses and bacteria that have insinuated themselves deeply inside a living organism and its cells, rather than the lack of exposure to microbes; so we might in this way eliminate autoimmune conditions as well once humans move into chiral life).
We would also need to be careful about human endogenous retroviruses (HERVs). These are virus gene coding sequences that exist within the human genome (they originate from ancient infections), which theoretically can come to life as a virus. HERVs are best eliminated from our genome before we switch to chiral form, otherwise if these ancient viruses come to life in chiral form, they could evolve and mutate into new retroviruses viruses that could infect chiral human being society. We want create chiral life completely and totally free of chiral viruses, or any other chiral microorganism.
There are other dangers too: imagine a reflected unicellular organism, which needs only light and symmetric molecules like H2O, CO2, O2. Such a chiral unicellular organism could spread, evolve, and could even overthrow plant life.
So the main rule from the beginning should be: in the case of chlorophyll organisms: only plants whose population can be controlled should be transformed!
Transformation of our ecosystem would be expensive, but in the future we may need to create completely new ecosystems for populating other planets like Mars. In these situations, the effectiveness of such an ecosystem will be very important. We would need many kinds of microorganisms. Symbiotic ones wouldn’t need to have aggressive mechanisms; aggressive microbes would only re-emerge if they evolved from zero. I cannot imagine that chiral viruses would be needed; they wouldn’t be transformed at all. Thus chiral viruses would just re-appear if they evolved from zero, like free DNA, which is unlikely. Furthermore, the last time this happened, the viruses evolved in parallel with their targets; now organisms have very advanced specific and non-specific defensive systems, which will make it hard for any chiral virus to appear and establish itself in a chiral ecosystem.
Of course, once our ecosystem is transformed, if in the distant future, we find a new major problem, we can always reverse again!
Another option, which is much easier, is to just switch humans to chiral form, leaving the rest of the ecosystem untouched. In the near future, it is likely that we will bio-engineer some of our food, so we could just bio-engineer our own factory-made chiral foods, without needing to introduce chiral plants for our crops, or chiral animals for our meat.
This chiral humans-only approach would be much easier and safer than converting the whole ecosystem to chiral form, and we could then enjoy all of nature in its pure and natural form, without ever having to worry about parasites or infections, which we will have jumped beyond forever.
Links:
http://www.sciencefo...in-chiral-life/
http://www.gregbear....play.cfm?id=982
Edited by Hip, 09 September 2012 - 04:10 PM.