Equalitarian Blood


Blood flows around the body all the time, yet we barely see it unless we suffer from an accident. If this were the case, and we lost too much of it, we’d need a blood transfusion. But it is not as easy as just putting blood from one individual into another: you need to test it and make sure the blood is compatible.

RBC

Can you guess what antigens these red blood cells have?

This occurs because human blood can be divided into many categories. The most common one is the ABO group classification, which divides blood into four types: A, B, AB and O. In each, red blood cells (those cells specialised in carrying oxygen around the body) have a specific antigen depending on the blood type. For example, if you have group A blood, you will have A antigens; if you have AB blood, you will have A and B antigens; and most importantly, if you have O blood, you will have no antigens.

Each antigen stimulates a response from our immune system to produces antibodies against the other antigens. So if you have blood group A, you will produce antibodies that will destroy cells with antigen B, and vice versa. This is potentially very dangerous, because if you give someone of type A blood from a person of type B, the antibodies can attack each other’s red blood cells and wreck havoc in our bodies.

When it comes to transfusing blood, the best one is group O- since it has no antigens, so there is no way your body can attack it. That is why we call it universal, since it works for anyone, no matter their blood type. This makes it very sought after for blood transfusions, but there isn’t always plenty of it available.

But what if we could convert all blood into O type blood? We can’t change the genotype of adults so that their body produced it, but we can change the blood itself after the blood has been donated. The most successful way to do this would be to insert bacterial enzymes into the blood which can recognise antigens in the red blood cells and cut them off so they are just like red blood cells from O group blood.

In the experiment which created this mechanism, the original enzyme worked mostly with cells from group B only, so to make it effective on cells from group A too they used a very interesting method called directed evolution. It’s just as it sounds: they grew the bacteria that produce this type of enzyme, and slowly mutated their genome (by adding bases to their DNA) so that every generation produced a better enzyme. At the end of the experiment, after 5 generations of bacteria, the final enzyme was produced, which not only could severe A antigens, but was also an impressive 170 times more efficient than the original one.

Yet this method is still not perfect: the enzyme can’t modify all the thousands of red blood cells in a sample of blood and therefore can’t make it completely safe, as there will still be some red blood cells with antigens present. But with enough time, the scientists hope to perfect it and make the technique available so blood transfusions are easier to carry out.

Micro Slavery


bacteria culture

This is the only way these modified organisms can live: in a dish in the lab

Bacteria can be both useful and lethal. In either case, scientists want total control over them to maximise their efficiency or prevent any diseases. However, it does sounds impossible: how can humans control a bacterium, which is a free living organism so small we can’t see it with our naked eye and is incapable of understanding our commands? But of course they have accomplished this, or otherwise I wouldn’t be writing an article on it.

Subjugating bacteria is done by a simple method. All living organisms require proteins made out of amino acids to live, and bacteria are no different. They use them to carry out many varied functions: they act as enzymes, hormones, connective tissue… so if you control how bacteria make proteins, you can basically dictate how they live their lives. Since proteins are coded by the DNA, scientists tweaked the genetic information so that bacteria didn’t code for proteins they way they would usually do. But changing the whole genome is a long, tiresome process; so instead, they targeted a specific set of genes which code for a specific set of proteins: those that are crucial for a bacterium to make other proteins. It is quite effective. If bacteria can’t make the proteins that guide DNA transcription and translation (the processes that produce proteins), then the bacteria are hindered and can’t work any further.

The modifications involved changing the bases in the DNA sequence so they didn’t code for the usual, natural amino acids. Instead, some new bases introduced coded for an artificial amino acid, created and only found in the lab, so proteins could only be made if this one artificial amino acid was present. This idea, although creative, was developed by two independent teams, one of which used a large, artificial amino acid and the other used three different artificial amino acids. Either way, if these bacteria wanted to survive, they would have to stay in the lab, the only place where they can obtain the amino acid necessary for creating proteins.

The main implications of this development are related to genetically modified organisms (GMOs). People fear that creating beings with features enhanced in the laboratory is dangerous, and if they somehow make it into the wild and grow there, they can harm other, more natural species, or reproduce with them, which would destroy the natural balance of natural selection. This technique solves both of those problems, since the new GMOs developed with dependency on this amino acid would only be able to live in the lab, and could be easily controlled and kept in small numbers.

Antibiotic Hero


Antibiotics are the real wonder drug. They were a revolution in the 20th century, capable of fighting the most powerful bacterial infections. Scientists understood their potential and worked tirelessly to create a wide variety of them to harness their power, but eventually they stopped. Since the 1980s, no new antibiotic has been discovered. Since we have a great amount of them, it wouldn’t be too big of an issue, if it weren’t for a growing problem: resistance.

Due to the threat antibiotics represent to bacteria, these organisms feel a high selection pressure to evolve and develop new ways to defend themselves from these drugs. And they have succeeded. Many strains of bacteria, especially for diseases like MRSA and TB, have become immune to many antibiotics and are proving really hard to fight. Due to the increase in antibiotic resistance, there has been a hunt for new antibiotics in the recent years, and it has finally paid off.

The most common way to obtain an antibiotic is from bacteria themselves. We are not the only ones who want to get rid of them; competing bacteria do too. So when these bacteria develop chemicals to destroy other bacteria, we need to extract them and use them to our advantage. But to extract the chemicals, bacteria need to be cultured in the lab, which can be difficult at time, since the most used bacteria for this process are found in the soil, which has conditions difficult to recreate in the lab. A new method created by researchers in Boston could solve this: it consists of creating a culture with three layers: two layers of soil on either side of a semi permeable membrane. These are perfect conditions for bacteria and have made it possible for thousands of them to grow and for a possible new antibiotic to be isolated.

teixobactin

Teixobactin could fight TB and other diseases which, over the years, have become immune to our medications

 It’s called teixobactin, and it targets proteins on the membrane of bacteria, eventually killing them. Because of its complicated mechanism, it is very hard for bacteria to develop resistance to its action. However, it is not impossible. Scientists predict that if used correctly (that is, without overprescribing), teixobactin could be effective for over 30 years, quite a long lifespan for an antibiotic. As it is completely new and bacteria have never been exposed to it, many say it could be the key to fight multidrug resistant bacteria, fighting superbugs and giving us and edge over the most fierce and dangerous infections. These hopeful results have yet to be confirmed in human trials, but the effectiveness of the new antibiotic seems to be as good as it sounds in animal tests.

 With this new method and this new antibiotic, the future of medicine could prosper, and bacterial infection could remain an enemy we can defeat.

A Bacterial Lunch


The secrets to weight loss may not lie on strange synthetic chemicals or unhealthy new fad diets, but actually in some simple bacteria we’ve known for as long as we’ve been born.

The bacteria in our intestines help us digest the food we intake; from carbohydrates to proteins to fats. But there’s something we humans can’t actually digest: fibre, so instead we use it to push the rest of the food through our guts and prevent constipation. However, since we should eat plenty of fibre, some bacteria use the excess and digest it too, and when doing so, release a substance scientists call propionate. This chemical triggers a reaction in our cells which results in them releasing a specific type of hormones: satiety hormones, such as PYY and GLP-1. As their name suggest, they are used by the body to make people feel ‘full’, by sending messages to the brain telling it to stop eating. In people, it usually takes a decent amount of fibre to trigger this response, so the person has to ingest a large amount of food before this reaction happens.

bacteria lunch

Don’t they look delicious?

But in developed countries, there is an excess of food, so people over indulge and end up over weight or obese. To stop this, scientists have been working with these bacteria in our guts and have come up with a possible solution.

In the form of IPE (inulin-propionate ester), propionate is in a concentration 8 times as large as that of a normal dinner, high enough to trigger the “I’m full” response despite not eating enough fibre. In theory, if a person takes this at some point during the day, they will produce the satiety hormones that will tell the body they are full so the person won’t feel the impulse to eat. The objective of the drug is therefore to reduce weight gain by reducing food intake.

To test this drug, some interesting experiments were carried out. The most curious one consisted of having two groups of people: one taking IPE and one not (the control) face a buffet and an open invitation to eat as much as they wanted (a.k.a. heaven). People with IPE in their system ate 14% less than those without IPE. And if the drug was given to people leading normal lives for six months, those taking the drug ate on average 9% less than those with no drug.

So although eating bacteria’s remains doesn’t sound like the most appealing plate in the book, it could produce long-term improvements in our health.

Superhero Chloroplasts


This week, I bring you another plant-related article, this time discuss how scientists are trying to upgrade the photosynthetic process in plants.

chloroplast

A chloroplast, which, in the future, could be filled with honeycomb-like structure called carboxysomes

It has been a billion years since an eukaryote ingested a chloroplast and by accident created the essential symbiotic relationship to which we owe all the energy by which we survive. However, the way chloroplasts work hasn’t really changed in all these years, even though the environment has, and its system is quite obsolete. On the other hand, the descendants from the species of the first chloroplast, the cyanobacteria, have really changed their photosynthesis, which is much more efficient than that of chloroplasts.

The main difference between our world and the world a billion years ago, at least for this topic, is CO2 and 02 levels in the atmosphere. Before, there was an enormous amount of carbon dioxide in the atmosphere, which cyanobacteria and chloroplasts could exploit to produce food by photosynthesis. But as plants became more abundant, they absorbed the CO2 and released 02 , giving rise to our current balance of elements in the air. The most favourable conditions for a fast photosynthetic rate are high levels of CO2 in the air but since this is not the case anymore, there is a need for some changes in the organisms themselves. Plants, which have remained mostly unchanged, have reduced their efficiency, whereas cyanobacteria, which have evolved, actually improved it. The key to their success lies in their ability to maintain high levels of CO2 within the cell, thanks to carboxysomes. These are tiny, regularly-shaped compartments that fill the bacteria, and are specialised in maintaining CO2 trapped in them, so there is more of it available for photosynthesis. They even have protein pumps in their membrane which actively pumps CO2 into the cell.

This unique mechanism is what scientists are now trying to copy into a normal plant chloroplast. To do so, they would use genetic engineering: adding genes from the marvelous cyanobacteria to the chloroplasts so they would develop the pumps, which could increase efficiency between 15-25%; an outstanding upgrade. Transferring the carboxysome technology would be a bit more complicated, requiring more genes and the knowledge on how to make the structure itself, which at the moment is lacking.

Still, this innovative improvement offers an immense upgrade, which would sure be useful to farmers and food suppliers, who have found a rapid increase in their customer pool but a slow increase in their yield, a problem which could be remedied if this solution worked.

As always, there is some opposition, arguing that if plants have evolved for millions of years and have never developed a new way for photosynthesis to occur, there must be a reason for a reason, so natured shouldn’t be tinkered with. The pros and cons for this situation are many, and it is a subject which divides the scientific community.

Pikachu Bacteria


Similar to Mary Shelly’s Frankenstein, scientists have discovered a type of bacteria that live only on pure electrons. Found in the seabed, in mud or rocks, these bacteria survive by extracting electrons from the surface of nearby materials, and after processing them and using their energy, they excrete them.

Although it sounds like a very simple and basic organism, its way of life is actually quite smart. In more evolved beings like us humans, we use many complex molecules to obtain energy: sugar and oxygen, which turn into ATP, and all this respiration process to end up with energy for survival. These bacteria manage to eliminate these useless (to them) intermediates, and just function with the basic electrons. They go for the easy route, whilst we masochists use larger molecules when all we really need are the electrons in those molecules.

electricity bacteria

These unimaginable bacteria live in electricty and from that they can extract everything they need to survive

However, these are not the first bacteria found to have this peculiar lifestyle. Other species, like the Shewanella or Geobacte bacteria do pretty much the same thing, but the novelty in this case is that the new bacteria can be found in large numbers by just applying a slight current through some seabed rocks. The fascinating experiment studied the microbiome of said rocks and analysed it, to determine how much voltage each of the new 8 bacteria species needed to survive. This eventually led to the recreation of those conditions in a culture, using a battery and an electrode to supply the energy to the bacteria. This simple way of life also raised a question: How much do these bacteria essentially need to survive? If all they need is electrons, by constantly feeding them these in a set of electrodes, they could theoretically live forever.

And as always, what some would call ‘greedy scientists’ are looking for ways to earn some profit out of their discoveries. In this case, it’s the possibility of automated biomachines, where these robots could carry out jobs with no necessary electrical input, only their ability to use power from their surroundings.

Life is all about Change


In an experiment in Michigan State University, scientist Richard Lenski started growing a group of E. coli bacteria in 1988. The bacteria have kept reproducing since then, making the incredible amount of more than 50,000 generations. But there is a purpose to this experiment: study evolution and answer a very simple question: Is there an end to evolution?

Lenski grew about 12 different groups of E.coli bacteria in a simple, constant medium. He used bacteria because this type of organism grows and reproduces very quickly and they are fairly easy to manipulate and study. It was important that the environment was kept constant, because any little change could affect the evolutionary process.

After every 500 generations, a sample was taken and frozen, so at some point, a group of bacteria from different generations was put together and their aptitude at surviving compared to each other is be measured.

The results are very surprising and revealing. Every generation, Lenski found, had a minor improvement over the former one. The grandson was always fitter than the grandfather; no matter how many times the experiment was repeated. But this was expected. The news is that, at some point, the improvements were less and less obvious, so even though there were still changes, they weren’t so useful or noticeable with each generation.

E. Coli bacteria

E. Coli bacteria

This is an example of power law, a mathematical term used to describe a sequence that is ever increasing, but the amount by which it grows, decreases.

This information is interesting because, up until now, it was thought that organisms had a limit as to how adapted they could be. This applies only to constant mediums. In the real world, there is always going to be changes, because the environment or the habitat changes all the time, however small the changes are. So the answer to our first question was no. There are always changes around us, so we are always going to be changing. Even if the world stopped changing in every minute detail, we would still be developing new ways in which to be fitter for survival.

Some people say that this could not be applied to humans or other species, but the idea is the same. Just like your parents said, there is always something you can do to be better.