Mostrando entradas con la etiqueta U of Bristol. Mostrar todas las entradas
Mostrando entradas con la etiqueta U of Bristol. Mostrar todas las entradas

martes, 21 de febrero de 2017

Scientists Just Found Evidence That Neurons Can Communicate in a Way We Never Anticipated

Andrii Vodolazhskyi/Shutterstock.com
A new brain mechanism hiding in plain sight. Researchers have discovered a brand new mechanism that controls the way nerve cells in our brain communicate with each other to regulate learning and long-term memory.

The fact that a new brain mechanism has been hiding in plain sight is a reminder of how much we have yet to learn about how the human brain works, and what goes wrong in neurodegenerative disorders such as Alzheimer's and epilepsy.

"These discoveries represent a significant advance and will have far-reaching implications for the understanding of 
  • memory, 
  • cognition, 
  • developmental plasticity, and 
  • neuronal network formation and stabilisation,"  
said lead researcher Jeremy Henley from the University of Bristol in the UK.

"We believe that this is a groundbreaking study that opens new lines of inquiry which will increase understanding of the molecular details of synaptic function in health and disease."

The human brain contains around 100 billion nerve cells, and each of those makes about 10,000 connections - known as synapses - with other cells.

That's a whole lot of connections, and each of them is strengthened or weakened depending on different brain mechanisms that scientists have spent decades trying to understand.

Until now, one of the best known mechanisms to increase the strength of information flow across synapses was known as LTP, or long-term potentiation.

LTP intensifies the connection between cells to make information transfer more efficient, and it plays a role in a wide range of neurodegenerative conditions -  
  • too much LTP, and you risk disorders such as epilepsy,  
  • too little, and it could cause dementia or Alzheimer's disease.
As far as researchers were aware, LTP is usually controlled by the activation of special proteins called NMDA receptors.

But now the UK team has discovered a brand new type of LTP that's regulated in an entirely different way.

After investigating the formation of synapses in the lab, the team showed that this new LTP mechanism is controlled by molecules known as kainate receptors, instead of NMDA receptors.

"These data reveal a new and, to our knowledge, previously unsuspected role for postsynaptic kainate receptors in the induction of functional and structural plasticity in the hippocampus," the researchers write in Nature Neuroscience.

This means we've now uncovered a previously unexplored mechanism that could control learning and memory.

"Untangling the interactions between the signal receptors in the brain not only tells us more about the inner workings of a healthy brain, but also provides a practical insight into what happens when we form new memories," said one of the researchers, Milos Petrovic from the University of Central Lancashire.

"If we can preserve these signals it may help protect against brain diseases."

Not only does this open up a new research pathway that could lead to a better understanding of how our brains work, but if researchers can find a way to target these new pathways, it could lead to more effective treatments for a range of neurodegenerative disorders.

It's still early days, and the discovery will now need to be verified by independent researchers, but it's a promising new field of research.

"This is certainly an extremely exciting discovery and something that could potentially impact the global population," said Petrovic.

The research has been published in Nature Neuroscience.

ORIGINAL: IFLScience
By FIONA MACDONALD
20 FEB 2017

sábado, 12 de diciembre de 2015

DNA sun protection

Researchers observe one of the world's fastest chemical reactions for the first time

Photo: .Enzymlogic, Licence: CC-BY-SA 2.0
UV radiation often damages our DNA. Researchers at Kiel University and The University of Bristol, Great Britain, have now seen for the first time what happens in DNA building blocks when they are stimulated by ultraviolet light, and what they do to prevent themselves from being destroyed. The results show: the molecules use the absorbed energy to set off a completely harmless reaction which prevents the genes being altered. The study can be found in the current edition of the journal Angewandte Chemie (Applied Chemistry).

Our DNA contains the bases adenine, guanine, cytosine and thymine. The chemists used ultra short blasts of light to shoot base pairs guanine and cytosine which were stimulated with UV light. They were only able to reveal the protective molecular mechanism using this method of femtosecond spectroscopy, because the process happened within a few quadrillionths of a second.

During the so-called electron-driven proton transfer process (EDPT), a hydrogen atom is displaced within the molecular compound. The base pair, however, immediately returns to its original starting structure from the same procedure. "Nature uses the reaction to strengthen the DNA's resistance to light by orders of magnitude - it is sort of a sun protection for DNA", said Professor Friedrich Temps, head of the Kiel research team from the Institute of Physical Chemistry. "The DNA building blocks themselves thereby relieve the cells' hugely complex and very slowly active repair mechanisms using enzymes. The discovery of these enzymes this year was awarded the Nobel Prize for Chemistry. Without the passive processes we observed, the cells' active repair mechanisms would be completely overloaded", added Professor Andrew Orr-Ewing, head of the team in Bristol. 

Katharina Röttger, Faculty prize winner for 2014 at Kiel University,
investigated a chemical process in DNA base pairs, together with colleagues, using extremely short pulses of light.
Photo/Copyright: Jürgen Haacks, Kiel University
In a few cases, however, the base pair was not able to return to the original situation. Here, EDPT caused two hydrogen atoms to be displaced. "The product could be a mutagen precursor and lead to DNA damage", explained Dr Katharina Röttger from the English working group, who received her doctoral degree in Kiel. Future experiments will have to show what then happens to this molecule. "We can only say that the potentially mutagen molecule survived our measurement time frame of one nanosecond (= a billionth of a second)", said Röttger. 

The scientists now want to find out whether the same processes also occur in a long DNA strand. The many interactions within and between the molecules and in the hydrogen bridges make this undertaking more complicated, however. Extremely fast reactions are often covered up by slower ones. Professor Temps and Professor Orr-Ewing are confident that the analysis tools of their working groups will soon be able to solve this puzzle, too.

Original publication
K. Röttger, H. J. B. Marroux, M. P. Grubb, P. M. Coulter, H. Böhnke, A. S. Henderson, M. C. Galan, F. Temps, A. J. Orr-Ewing, G. M. Roberts, "Ultraviolet Absorption Induces Hydrogen-Atom Transfer in G?C Watson-Crick DNA Base Pairs in Solution", Angew. Chem. Int. Ed. 54, (2015). DOI: 10.1002/anie.201506940

ORIGINAL: .Kiel University

viernes, 23 de octubre de 2015

Robot With Tummy Full of Microbes Can Swim in Dirty Water Forever


Image: University of BristolRow-bot with mouth open (inset shows mouth closed).
Robots are better than animals in almost every way. Well, they’re better in some ways, I guess. I mean, robots are occasionally okay at some things. A few things. None of those things are energetic autonomy: the ability to operate continuously and indefinitely without dependence on humans for refueling. There certainly are robots that operate autonomously for long durations, and they’re either feeding off of radioactivity, or they’re relying on solar panels that don’t work half the time. A better option (at least in some situations) might be robots that forage for food like animals do, taking care of their own energy needs all by themselves.

This is only a slightly crazy idea (although at one point it was briefly the craziest idea ever), and fuel cells that are full of living microbes are a real thing. At the Bristol Robotics Laboratory, in the United Kingdom, they’ve been developing a robot called Row-bot that can swim around, harvesting energy directly from the water using a microbial fuel cell as an artificial stomach.

According to the researchers, Microbial Fuel Cells (MFCs) generate electricity by “electrons mobilised by the redox reaction that takes place in electrogenic bacterial anabolism.” More specifically, in the case of their device, they explain that “raw organic biomass is used as both an inoculant for the bacterial culture and the anolyte that fuels the reaction resulting in an environmentally biocompatible means of electricity generation.” In other words (simpler ones), microbes eat stuff in the water and poop out electrons, and as long as you’ve got enough water with stuff in it to keep the microbes fat and happy, they’ll keep giving you electrons that you can use to make your robot do things. MFCs work in all kinds of water, including fresh water in rivers and lakes, seawater, and even waste water, and they actually clean the water as they go, which is nice.

Microbes are kind of tiny, and each one doesn’t produce a lot of energy, so to do anything useful, you either need a whole bunch of them (multiple fuel cells) or a very efficient robot. Row-bot is very efficient, modeled on a water beetle. It has two side paddles to move, little floaty feeties to keep it from drowning, and a microbial fuel cell in its tummy:


It has a mouth, too, that it can open to ingest water for the fuel cell, and also a fuel outflow port on its posterior end that we’d call its butt if we were immature, which we’re not. Each time the robot opens its mouth, it swims forward, ingests fresh water into its MFC tummy, digests for 3 minutes, and then expels the water out the back as it swims forward again, making room for a fresh gulp. Row-bot stores the energy generated by the MFC in a capacitor, and over one cycle (opening its mouth, swimming 10 strokes forward at just under 1 stroke per second and then closing its mouth), it only uses 1.8 joules. That’s 20 centimeters of motion with about 1 joule of energy leftover that could potentially be used to power sensors or laser turrets or something. 

As long as Row-bot has water to swim through, the MFC makes it more or less energetically autonomous, although the current design is mostly a testbed for integration of the MFC with actuators to see how well it works. There’s a lot more optimization that needs to happen, like reducing body drag and finding the most efficient combination of materials to use for the paddles, as well as altering the “stride” of the robot to better mimic actual water beetles. Also, multiple MFCs could be configured in series if you need more power for those aforementioned laser turrets.

Eventually, the researchers suggest that Row-bot could be developed for applications such as remote sensing and environmental monitoring and clean-up, although space exploration isn’t out of the question either.

Also, it’s called “Row-bot.” Get it? Row-bot the robot. Heh.

Row-bot: An Energetically Autonomous Artificial Water Boatman,” by Hemma Philamore, Jonathan Rossiter, Andrew Stinchcombe, and Ioannis Ieropoulos from the University of Bristol and University of the West of England, was presented at IROS 2015 in Hamburg, Germany.

Learn More fuel cell iros iros 201

ORIGINAL: IEEE Spectrum
By Evan Ackerman
Posted 22 Oct 2015

jueves, 27 de diciembre de 2012

Lake Ellsworth Antarctic drilling project called off

ORIGINAL: BBC
Analysis David Shukman Science editor, BBC News

The team burned much of its fuel in a bid to connect the under-ice boreholes

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An ambitious mission to drill through 3km (1.8 miles) of Antarctic ice to a lake that has been sealed off for thousands of years has been cut short.

The team at Lake Ellsworth decided to call off the mission in the early hours of Christmas Day UK time.

They were unable to join the main borehole with a parallel hole that was to be used to recover drilling water.

The team is now "weatherising" the equipment and it is unclear when they will be able to resume the project.

The £8m ($13m) project, headed by the British Antarctic Survey (Bas), aimed to drill carefully down using near-boiling water to pierce the lake, which has been untouched for as much as half a million years.

The hope had been to find hints of simple life forms existing in the extreme conditions of pressure and temperature, and to find a record of climate in the lake's sediments.

Searching for life in the hidden waters of Lake Ellsworth was one of the most ambitious British science projects of recent years, so this failure in the drilling programme will come as a huge blow.

The team knew that the risks were high, but the idea of exploring an ancient and mysterious body of water isolated for hundreds of thousands of years had inspired passion and determination.

The challenge of designing and engineering equipment that could remain sterilised on the long journey to Antarctica, and then down through the 3km of ice-sheet, was immense and involved hundreds of people.

So the disappointment will be felt far beyond the 12 men at their remote camp on the ice. Engineers, technicians, support staff - and researchers eager for the results - will feel heavy disappointment. They may try again next year. But this was frontier science, a gamble, and it did not pay off.

The programme ran into trouble last week as the main boiler used to heat drilling water broke down, with a replacement part being flown from the UK reaching the remote site last Friday.

With the boiler working, the team aimed to make two parallel boreholes, intended to join 300m below the surface.

A first borehole was drilled and left for 12 hours to create a hot-water cavity. This was to be used to re-circulate drilling water and to balance pressures when the sequestered lake was finally breached.

However, the team were unable to reach the cavity during the course of drilling the second, main borehole.

"We kept trying for over 24 hours to reach that connection but we couldn't do it," said principal investigator of the project Martin Siegert, from the University of Bristol.

"All that time we were losing fuel and water from the ice sheet surface and we got to a critical condition where our calculations showed us we simply didn't have enough fuel to continue any further down into the ice sheet to hit the top of the lake," he told BBC News.

The team is now starting the long process of gathering up its equipment for eventual return to the UK, where it will be serviced.

Once back on UK soil, the team will have to develop a report on what went wrong, and only then can the thought of a return trip be considered.

"It will take a season or two to get all of our equipment out of Antarctica and back to the UK, so at a minimum we're looking at three to four, maybe five years I would have thought," Prof Siegert said.

But he remained hopeful about the future, and said that this year's mission was far from a complete loss.

"We still want to do that testing, they were compelling scientific drivers a few years ago and they remain so. It's very important that we take stock of what we achieved here," he said.

Given the long time that it may take to fund and mount another mission to Ellsworth, it may be that other nations aim for other sealed-off Antarctic lakes in the nearer term.

"We have never depicted it as a race, but it may well happen that others get there first," Audrey Stevens, Bas spokesperson, told BBC News.

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