“NOT ONLY OUR FUTURE, WE CAN ALSO BECOME GREEN”
Year 2085, Government had passed an act to ban buildings. People live in glass houses similar to that of green houses. These houses are specially designed to receive maximum sunlight. Human population is now uniformly spread in the world, even in deserts and colder climates. There is no distinction between city and village. Human localities are now termed as Cerysiums (Cerysiums = Ceres+Elysium, Ceres –Roman goddess of food and agriculture, Elysium – Place like heaven.). Food and agriculture industry is now a history and no more farmers exist. Dairy, fishery and beef industry is lost. Food biotechnology is focused only on producing nutrients like vitamins, amino acids, nucleic acids etc. Very few restaurants left are now included as world heritage sites.
Confused or exited?
Generally future visualized by scientists is confusing compared to that shown by palmitologists. Science not only shows the future, it practically takes us to the future. It also tells the problems that might arise in reaching that future and also tries to solve them.
Human mainly race for 3 main needs. What we call in our language as “Roti, Kapda and Makan”. Now we are at the point where we can solve the problem of food forever.
Before entering into what is my idea about solving this problem of “Roti” let’s understand how we obtain food now.
What is food? Food is a complex organic mixture that we are consuming, mainly to obtain energy. We are vegetarian or non vegetarian. Our food contains organic molecules like carbohydrates, proteins, nucleic acids, fats etc. which are digested and converted through many processes into glucose. We use glucose for our all energy requiring processes. Now again the question arises that from where this energy gets stored into plants and animals. Plants can trap the energy of photons (sunlight) and convert it into glucose. This glucose is converted in starch, cellulose and other complex organic compound. Animals depend on these for their energy source. Earth gets its almost energy from the sun as sunlight. Plants and other photosynthetic organisms use this radiation energy and convert it into chemical energy in the form of glucose and other organic molecules. And that is the reason why this organisms are called autotrophs (auto – self). Plants can convert sunlight into chemical energy because they have chloroplast which can trap the energy of sunlight and use it to synthesize glucose (Ref. light and dark cycles of photosynthesis). They oxidize this glucose for their metabolic process and left over energy is stored by plants.
Herbivores eat plant and get the energy, use it for metabolic purpose and left over energy is stored in their body. Carnivores eat herbivores and get the energy. Humans eat plants or herbivores and obtain whatever energy that is stored in them. Thus on our planet glucose is the main source of energy.
Now let’s talk about the biochemistry of glucose oxidations so that we can understand how actually glucose gives energy. Glucose is oxidized in mitochondria. Mitochondria is a cellular organelle that is specialized for the oxidation of glucose (Ref. mitochondrial oxidation). Mitochondria is a double membraned organelle as shown in the diagram. Inner membrane is having enzyme machinery which oxidizes glucose products to pump out H+ from the matrix into the inter membrane space. Thus, oxidation of glucose leads to accumulation of H+ in the inter membrane space. Thus H+ tries to get back into the matrix and creates a ‘push’ on the inter membrane. One more machinery called ATPase uses this ‘push’ to generate ATP. This ATP is used as energy currency in the cell. All cells work on ATP, no cell can work without ATP. All living processes use this ATP as a source of energy. Every biochemical process works with ATP. Thus, all organisms produce ATP to run their life.
Now we know that human need to depend on other organisms for food because we can not produce glucose on our own. So we use external source of glucose and then oxidize it to get ATP. Thus human are heterotrophs( hetero- other, double). So the energy flows from sun to plants to animals and then to us. And during this transfer much of energy is lost and so our food is a costly affair for us. So can it be possible that we by pass plants and animals and obtain our energy directly from the Sun?.?.?
Many scientists thought about this and some imagined “green man” who is having chloroplasts in their cells. This chloroplast was of plants and thus capable of photosynthesizing like plants and thus human can get their food directly when they stand in sunlight, exactly like plants do.
This thing is practically not possible, as we all know that chloroplast is very big organelle and having thousands of proteins associated with it. So practically it is not possible to incorporate this organelle into human cells.
Before entering into some other discussion let’s talk about one bacterial protein that is having photosynthetic activity. Bacteriorhodopsin is a protein found in Bacteria halo bacterium. It is a very primitive type of bacteria which is also capable of synthesizing its own food. This bacterium shares a unique combination of mitochondria and chloroplast. Bacteriorhodopsin is a light sensitive protein and whenever it is exposed to sunlight it pumps out one H+ in the space between the membrane and cell wall. Thus till the time the Bacteriorhodopsin is exposed to sunlight it keeps on pumping out H+ out of the cell. Thus H+ keeps accumulating in the space between the cell wall and membrane and tries to “push” in to the cell. This bacterium also has enzyme machinery like ATPase of mitochondria and it functions similar to that of mitochondrial ATPase. So it also uses the ‘push’ of H+ and generates ATP. Thus bacteria can obtain ATP using sunlight.
Here my hypothesis is that what will happen if we incorporate the bacteriorhodopsin molecule into the inner membrane of mitochondria..,,,??? Whenever the cell is exposed to light, the bacteriorhodopsin will pump out H+ into the inter membrane space as it happens in the glucose oxidation. Thus H+ will keep accumulating in the inter membrane space (same like that happening in during glucose oxidation). And these H+ will try to ‘push’ in the mitochondrial matrix and the ATPase enzyme will use this “push” to generate ATP..,.,,,, Eureka !!!!!! We don’t need to depend on glucose to generate ATP i.e, energy.
So if you have bacteriorhodopsin in your mitochondrial inner membrane, you don’t need to depend on glucose. Just go and have sun bath! Bacteriorhodopsin will pump H+ in the inter membrane space. ATPase will use this H+ push to generate ATP. You don’t need to depend on the external glucose source.
Exiting na .?.
But the thing is not as easy as we think. Dealing with live cells is very difficult. As I had said in the beginning, science not only dreams but also leads us to full fill the dream.
Initially, we can start with experiments on cell culture. Here we can use the bacteriorhodopsin protein directly. In the living cells we can insert the bacteriorhodopsin in the cell using different techniques available now a days. After the protein gets into the cell we can direct this protein in the mitochondrial inner membrane using tagging sequences that specify the protein towards mitochondria.( Our cells have specific protein sorting mechanisms, i.e, there are specific sequences in the starting of protein which directs it to mitochondria or to other organelle.) Once protein gets into the mitochondrial inner membrane,. we can check for its functioning. Whenever the cell will be exposed to sun light it will be able to synthesize ATP.
But this is the story of one single cell. We can not use this method for practical application at organism level, having billion of cells. Here comes the role of genetic engineering. We can transfer the genes of bacteriorhodopsin operon( operon is the set of genes in bacteria) in the mitochondrial genome. Now with the other genes of mitochondria bacteriorhodopsin will also be expressed and its protein will be formed which will get into the mitochondrial inner membrane and start functioning.
So if we can do that successfully, all of our body cells that are exposed to sun light will become capable to produce ATP without glucose and use this ATP. The left out ATP can convert to Glucose and transfer it to other cells and they can also use it. Thus we don’t need to depend on plants and animals for our energy source. All we need is the nutrients like vitamins and other amino acids etc., which we can take as tablets as they are required in very little quantities.
This thing might appear very exiting but it is a fiction-cum-dream. We don’t know what will happen if we do this. We-eukaryotes are living with glucose oxidation from at least 2.5 billion years. F.e, if glucose oxidation won’t be required, what will happen to the hundreds of enzymes of glycolysis, Kreb’s cycle and ETS. What will be the systemic effect of this, as there are several hormones associated with it, what will be effect on the digestive systems, what will happen to our metabolism? There are thousand many questions that can be asked about it. Not only this, if it really happens so, our life and environment will get totally changed, we won’t need plants and animals. It will change human lives totally.
The changes it can cause are unpredictable. Entire world might be altered because of it, or the other thing that can happen with this thought is very possible. This thought arose in my mind, I took it down on paper and it will over here only.
The possibility of other case is 99.9%. My thought might get a practical shape but, I know that the possibility is very little. People won’t accept it, as nobody likes sudden changes. I don’t regret that my idea will be wasted, because I know that it is the nature of living animals that they don’t like sudden changes, as they are difficult to adapt.
One more question is of ethical problems, Nature created us for glucose oxidation, and it took 2 billion years to bring us to this level and we should not change it. I am a scientist and doing experiments is in my hands, I would like to do this experiment on other non human experimental models and make them autotrophic.
If it is successful in other models then should we try it humans?
I don’t have any answer to it., so I leave it on you…..
For further discussion and suggestions or firings please contact
Ayaz Rangrez (9924422717)
ayaz_kaish@yahoo.com
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