Robot Yeast


A milestone in biology was reached this month when scientists in USA were able to create an entirely synthetic chromosome from a Saccharomyces cerevisiae, commonly known as yeast, in the lab.

chromosome

A chromosome has been created for the first time in the lab, step by step

To start this process they identified the full genetic sequence of yeast’s chromosome III, chosen because it’s one of the smallest chromosomes and can therefore be replicated more easily.
But it was still too big, so they took out a few less than 45,000 nucleotides, all of those thought to be ‘junk’ DNA, that is, DNA that doesn’t seem to have any function. This left 270,000, all of which had to be joined together to make up the chromosome, starting from scratch.
This is an enormous amount of work, so they ended up working with a team of 60 undergraduates, each team building a part of the chromosome until they were all joined together to form the final masterpiece.
Once the chromosome was ready, they inserted it into the yeast cell, and fortunately it seemed to work just as fine as the natural one would. They are now working on repeating this task on the whole of the yeast’s genome, instead of only one chromosome.

There have been some experiments in the past which managed to recreate the genome of organisms, especially bacteria, but no one up until now had managed to change it so much and still have it work. It is an outstanding feat in science that could teach biologists a lot more on how genes work and interact with each other.

However, this achievement is not only good in the way of creating artificial life, but it could also show some improvements in the chemical industry world.
When they decided which nucleotides to take out, they also haad to chose some changes to be made to the genome, so as to learn something from the genes changed. One of these tweaks was to change the stop codon, TAG, to TAA. This meant that TAG now doesn’t code for anything, but scientists could change this so it codes for a new amino acid, not found in the cell before. This could give rise to new substances and biopolymers, whose properties could prove to be very useful. If this worked, we could eventually have cells become factories, all with changed genetic sequences, so they produced new chemicals for many possible functions.

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Humans Are Suprisingly Nosy


There have been plenty of studies on the human vision and hearing senses, but there is rarely one on our smelling sense. But this time, a group of researchers at Rockefeller University in NYC decided to break the rule and have arrived to a fascinating conclusion.

rose

A rose’s smell is composed of many odorant molecules that combine to give off that particular scent

Normally, a smell is a mixture of hundreds of different odorant molecules, and particular combinations of these give rise to a variety of smells, such as chocolate and flowers.
Based on this idea, these scientists produced three types of mixtures out of 128 odours, having 10, 20 or 30 of them in each mixture with different combinations. These were then given to a group of inexperienced volunteers, in the form of three samples: two of the same mixture and a different one.

Results were collected, and using mathematics such as the probability theory, they reached the verdict that there were more than a trillion combinations of those odours, which is also quite an underestimate since there are many more existing odours.
These results differ drastically from previous experiments, like the last one, made in the 1927, which said that humans were able to tell only 10,000 smells apart.
Not only that, but it also makes the olfactory sense defeat the visual sense since it can distinguish far more stimuli. In fact, the human eye can differentiate 10 million colours (which is still pretty good), but means that our sense of smell is 100,000 times more varied than the sense of vision.

The obvious conclusion was that the more common odorants two substances shared, the harder it was to distinguish them. However, volunteers proved to be quite good at distinguishing smells, but not as good at naming them. A possible reason is that although we have more than 400 receptors in our nose, the olfactory nerves are not connected to the area in the brain where language is used.
It is still very remarkable that humans have the capability of setting apart such a great number of smells, and scientists are already working on expanding their knowledge on the smelling sense using this investigation and its consequences.

Detecting Baby Waves


In Einstein’s theory of general relativity, he said that massive objects moving at incredible speeds, or giant objects’ gravity interacting could cause ripples in the space-time fabric, known as gravitational waves. They had been searched by scientists for years, and they had successfully hidden, but not anymore.

A series of experiments taking place in the South Pole have finally provided the scientific community with a solid detection of these elusive waves. The project, called BICEP2, has released its findings today, and are awaiting further revision for official publication.

gravitational echo

The graph showing the primoridal gravitational waves when first detected.

There has been a lot of excitement over these waves, because they are able to prove one of the most popular theories regarding the birth of our universe: inflation. The theory, suggested by physicist Alan Guth, says that a few moments after the universe was created, it suffered a dramatic increase in size (by a factor of 1078). After this, its expansion rate slowed down considerably.

What’s important is that if this theory was correct, the sudden growth would have caused ripples in the space-time, hopefully strong enough for us to detect.

And this is what this amazing team has done. They have detected the gravitational waves that were given off during the expansion, given the fancy name of primordial gravitational waves.

The results are impressive just by themselves. The fact they have caught these waves is already world-changing, but there are even more interesting details that deserve our attention.

The waves they found were stronger than they thought they could be, which leads to a rethinking of the current inflation theory. There are some ‘sub-theories’ that can explain this fact, so many eyes are turning towards these and reconsidering them for answers.

But if there’s something we’ve learnt after all these years is to remain cautious after big discoveries (incredible stem cell method not that incredible after all?). The findings have yet to be backed up by other experiments from other teams, but overall there is a positive feeling towards this data.

If they were to be true, they would prove inflation to be true once and for all, but they could also prove useful in completing quantum mechanics. This field is very effective when working with subatomic particles, but when you add gravity, it all goes to rubbish. An understanding of gravitational waves could be useful and could help scientists find that key they need to wrap it all up.

 

Check out BICEP2’s official website:

http://www.cfa.harvard.edu/CMB/bicep2/science.html

Quantum Droplet


Quasichemistry is a branch of chemistry that studies a special type of particles called quasiparticles.

These are different from normal particles because they cannot exist individually, but only inside of solids. They act as if they were floating freely in space, with weak interactions with other particles.

For example, it is believed an electron, although a fundamental particle (the simplest substance which doesn’t have any substructure), is made of 3 quasiparticles, a holon, a spinon and an orbiton. Each of these quasiparticles has a different characteristic that codes for the electron. The holon carries the electron’s charge, the spinon its spin and the orbiton its location in the orbit.

dropleton

Named dropleton because it’s like a liquid drop

However, they are not real particles, just a mathematical tool used to simplify the way electrons and nuclei move in a specific way.

There have been many quasiparticles discovered, and they are used to explore the quantum world in more depth. So every time a new quasiparticle is discovered it’s a celebration that we are closer to understanding physics at it’s smallest level.

Recently, a new quasiparticle was created, the “dropleton” (named because it’s a quantum droplet).

The way it is created is when a short laser pulse was directed at a semiconductor made of gallium arsenide. The energy given to the material causes electrons to move, creating excitons (pairs of holes in a material because of the absence of an electron). Once there are many excitons, they start joining to electrons, and moving around the solid.

But what’s interesting is the way they travel. Normal quasiparticles move like normal particles, but the dropletons flowed, rather than moved. In fact, they behaved like a group of particles in a liquid. It’s the first quasiparticles to act in a liquid fashion.

They are also special because of their longevity. They last for 25 picoseconds, which although is extremely short period of time for us humans it is quite a long time in the quantum world. This and their size (200 nanometres) allows scientists to test them and discover more about them. Not only that, but they also form stable structures. The smallest dropleton is 4 electron-hole pairs; the biggest is 14.

Autism Hates Males


Autism is a genetic condition that affects both males and females, but a recent study suggests that women have a special protection against this disorder that men lack.

For a person to become autistic there must be a genetic mutation. Sometimes it only takes a mutation in one gene, but normally it is a group of mutations that end up causing autism. In fact, throughout the years, there’s been hundreds of mutations discovered that have the ability of causing it. But now we know that the number of genes that cause autism in humans can be different depending on gender.

This difference because of sex was found out by a group of scientists in the University Hospital of Lausanne in Switzerland, where more than 700 families with a child with autism were tested, and their genome analysed.

They were looking for two different types of mutations: copy number variations (where large parts of the genetic material is destroyed or duplicated) and single gene mutations. The conclusion was females were three times more likely to have more of these mutations than males.autism

The fact that girls have to have more mutations to contract this condition means they are more protected than men, which explains why there are 4 times as many male autistic people as there are females. So their brains can work better with mutations than men’s with the same mutations.

To back these results, there’s been another investigation, from the Autism Genome Project, with 2400 patients, which shows similar results. The aim of this foundation is to map the genome of as many autistic people as possible, so as to find a trend they could understand and translate it into a treatment for autism. Although there is still no conclusion, there is progress in this field, demonstrated by this discovery. If we were able to decipher the way in which females are protected, we could be closer to creating a cure for this condition suffered by more than tens of millions of people worldwide.