HOW GUT BACTERIA COULD EFFECT BRAIN AND BODY

Research published in the open access journal Microbiome sheds new light on how gut bacteria may influence anxiety-like behaviors. Investigating the link between gut bacteria and biological molecules called microRNAs (miRNAs) in the brain; researchers at the APC Microbiome Institute at University College Cork, which is funded by Science Foundation Ireland, found that a significant number of miRNAs were changed in the brains of microbe-free mice. These mice are reared in a germ-free bubble and typically display abnormal anxiety, deficits in sociability and cognition, and increased depressive-like behaviors.

Dr Gerard Clarke, the corresponding author said: “Gut microbes seem to influence miRNAs in the amygdala and the prefrontal cortex. This is important because these miRNAs may affect physiological processes that are fundamental to the functioning of the central nervous system and in brain regions, such as the amygdala and prefrontal cortex, which are heavily implicated in anxiety and depression.”

miRNAs are short sequences of nucleotides (the building blocks of DNA and RNA), which can act to control how genes are expressed. miRNA dysregulation or dysfunction is believed to be an underlying factor contributing to stress-related psychiatric disorders, neurodegenerative diseases and neurodevelopmental abnormalities. miRNA changes in the brain have been implicated in anxiety-like behaviors.

Dr Clarke said: “It may be possible to modulate miRNAs in the brain for the treatment of psychiatric disorders but research in this area has faced several challenges, for example, finding safe and biologically stable compounds that are able to cross the blood-brain barrier and then act at the desired location in the brain. Our study suggests that some of the hurdles that stand in the way of exploiting the therapeutic potential of miRNAs could be cleared by instead targeting the gut microbiome.”

The researchers found that levels of 103 miRNAs were different in the amygdala and 31 in the prefrontal cortex of mice reared without gut bacteria (GF mice) compared to conventional mice. Adding back the gut microbiome later in life normalized some of the changes to miRNAs in the brain.

The findings suggest that a healthy microbiome is necessary for appropriate regulation of miRNAs in these brain regions. Previous research demonstrated that manipulation of the gut microbiome affects anxiety-like behaviors but this is the first time that the gut microbiome has been linked to miRNAs in both the amygdala and prefrontal cortex, according to the authors.

The researchers used next-generation-sequencing (NGS) to find out which miRNAs were present in the amygdala and the prefrontal cortex of groups of 10-12 control mice with a normal gut microbiota, GF mice and ex-GF mice – which had been colonized with bacteria by housing them with the control mice – and adult rats whose normal microbiota had been depleted with antibiotics.

They found that depleting the microbiota of adult rats with antibiotics impacted some miRNAs in the brain in a similar way to the GF mice. This suggests that even if a healthy microbiota is present in early life, subsequent changes in adulthood can impact miRNAs in the brain relevant to anxiety-like behaviors, according to the authors.

The authors note that the exact mechanism by which the gut microbiota is able to influence the miRNAs in the brain remains unclear. Even though the study shows that effects of the microbiota on miRNAs are present in more than one species (mice and rats), further research into the possible.connection between gut bacteria, miRNAs and anxiety-like behaviors is needed before the findings can be translated to a clinical setting.

Dr Clarke said: “This is early stage research but the possibility of achieving the desired impact on miRNAs in specific brain regions by targeting the gut microbiota – for example by using psychobiotics – is an appealing prospect.”

Source:
https://www.biomedcentral.com/about/press-centre/science-press-releases/25-08-17

Journal article:
https://microbiomejournal.biomedcentral.com/articles/10.1186/s40168-017-0321-3

#infopraphic via The Huffington Post

#gutbacteria #miRNAs #gutmicrobiota #anxiety #prefrontalcortex #amygdala #neuroscience

A Rapid Eye Movement Test That Could Help Diagnose Autism Disorders

Neuroscientists at the University of Rochester have masterminded a rapid eye movement test that can detect abnormalities in the cerebellum (Latin for "little brain") that also appear to be a marker for certain autism spectrum disorders (ASD).

Their paper, "Eye Movements, Sensorimotor Adaptation and Cerebellar-Dependent Learning in Autism: Toward Potential Biomarkers and Subphenotypes," was published online July 12, 2017 in the European Journal of Neuroscience. >>
http://onlinelibrary.wiley.com/doi/10.1111/ejn.13625/full

In a series of experiments, the authors of this study had individuals with and without ASD track a visual target as it zoomed around to different locations on a screen. As participants' eyes darted across the screen chasing a target, the researchers were tracking their rapid eye movements (also known as "saccades"). Saccades are the synchronized rapid movements both eyes make as your gaze and attention quickly shifts from one point of focus to another.

“These finding suggest that assessing the ability of people to adapt saccade amplitudes is one way to determine whether this function of the cerebellum is altered in ASD,” said Edward Freedman, Ph.D. an associate professor in the URMC Department of Neuroscience and co-author of the study.
“If these deficits do turn out to be a consistent finding in a sub-group of children with ASD, this raises the possibility that saccade adaptation measures may have utility as a method that will allow early detection of this disorder.”

► Learn more>> https://www.urmc.rochester.edu/news/story/5102/eye-test-could-help-diagnose-autism.aspx

► Image credit: 8thstar/CC 3.0>> https://commons.wikimedia.org/wiki/Human_eye#/media/File:A_blue_eye.jpg

Quantum Chemistry Solves The Question of Why Life Needs So Many Amino Acids

Quantum Chemistry Solves The Question of Why Life Needs So Many Amino Acids

A flexible approach to life.

DAVID NIELD

3 FEB 2018

One of the oldest and most fundamental questions in biochemistry is why the 20 amino acids that support life are all needed, when the original core of 13 would do – and quantum chemistry might have just provided us with the answer.

According to new research, it's the extra chemical reactivity of the newer seven amino acids that make them so vital to life, even though they don't add anything different in terms of their spatial structure.

Quantum chemistry is a way of taking some of the principles of quantum mechanics – describing particles according to probabilistic, wave-like properties – and applying them to the way atoms behave in chemical reactions.

The international team of scientists behind the new study used quantum chemistry techniques to compare amino acids found in space (and left here by meteorite fragments) with amino acids supporting life today on Earth.

"The transition from the dead chemistry out there in space to our own biochemistry here today was marked by an increase in softness and thus an enhanced reactivity of the building blocks," says one of the researchers, Bernd Moosmann from Johannes Gutenberg University Mainz in Germany.

It's the job of amino acids to form proteins, as instructed by our DNA. These acids were formed right after Earth itself came into being, about 4.54 billion years ago, and so represent one of the earliest building blocks of life.

However, why evolution decided that we needed 20 amino acids to handle this genetic encoding has never been clear, because the first 13 that developed should have been enough for the task.

The greater "softness" of the extra seven amino acids identified by the researchers means they are more readily reactive and more flexible in terms of chemical changes.

If you were representing the amino acids as circles, they could be drawn as multiple concentric circles representing differing energy levels, rather than one single circle of the same chemical hardness and energy level – kind of like in the photo below.

                                                                                                       (Michael Plenikowski)

                                                              

Having determined the hypothesis through quantum chemistry calculations, the scientists were able to back up their ideas with a series of biochemical experiments.

Along the way the team determined that the extra amino acids – particularly methionine, tryptophan, and selenocysteine – could well have evolved as a response to increasing levels of oxygen in the biosphere in the planet's youngest days.

Peering so far back in time is difficult, as the first organic compounds never left fossils behind for us to analyse, but this may have been part of the process that kicked off the formation of life on Earth.

As the very earliest living cells tried to deal with the extra oxidative stress, it was a case of survival of the fittest. The cells best able to cope with that additional oxygen – through the protection of the new amino acids – were the ones that lived on and flourished.

"With this in view, we could characterise oxygen as the author adding the very final touch to the genetic code," says Moosmann.

The research has been published in PNAS.

                                                     --by Sciencealert.com