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Comment by Dr. Krishna Kumari Challa on November 17, 2021 at 9:48am

Synthetic biology yields easy-to-use underwater adhesives

Several marine organisms, such as mussels, secrete adhesive proteins that allow them to stick to different surfaces under sea water. This attractive underwater adhesion property has inspired decades of research to create biomimetic glues for underwater repair or biological tissue repair. However, existing glues often do not have the desirable adhesion, are hard to use underwater, or are not biocompatible for medical applications. Now, there is a solution from synthetic biology.

Researchers  have developed a method that uses engineered microbes to produce the necessary ingredients for a biocompatible adhesive hydrogel that is as strong as spider silk and as adhesive as mussel foot protein (Mfp), which means it can stick to a myriad of surfaces underwater.

The team integrated the silk-amyloid protein with Mfp and, using a synthetic biology approach, synthesized a tri-hybrid protein that has the benefits of both the strong adhesion of Mfp and the high strength of spider silk. Using the tri-hybrid protein, they prepared adhesive hydrogels.

Because the protein-based adhesive can be biocompatible and biodegradable, the lab is particularly excited about its potential applications in tissue repair. This protein, they write in the paper, is particularly attractive for tendon-bone repair, which suffers from a high failure rate from current suture-based strategies.

Eugene Kim et al, A Biosynthetic Hybrid Spidroin-Amyloid-Mussel Foot Protein for Underwater Adhesion on Diverse Surfaces, ACS Applied Materials & Interfaces (2021). DOI: 10.1021/acsami.1c14182

https://phys.org/news/2021-11-synthetic-biology-yields-easy-to-use-...

Comment by Dr. Krishna Kumari Challa on November 17, 2021 at 9:23am

Killing bacteria with nanoparticles

Researchers  have developed a new technology based on nanoparticles to kill dangerous bacteria that hide inside human cells.

Burkholderia is a genus of bacterium that causes a deadly disease called melioidosis. This disease kills tens of thousands of people each year, particularly in southeast Asia. Antibiotics administered orally or intravenously often don't work very well against it as the bacteria hide away and grow in white blood cells called macrophages.

New research has shown that tiny capsules called polymersomes—which are about 1000th the diameter of a human hair—could be used to carry bug-killing antibiotics right to the site where the bacteria grow inside the cells. Their findings have been published in the journal ACS Nano.

Macrophages are cells of the immune system that have evolved to take up particles from the blood which is crucial to their role in preventing infection, but it also means that they can be exploited by some bacteria which infect and grow inside them.

In this study, the research team added polymersomes to macrophages which were infected with bacteria. Their results showed that the polymersomes were readily taken up by the macrophages and associated with the bacteria inside the cells. This means they could be an effective way to get a high concentration of antibiotics to the site of infection. The team hope this could eventually lead to patients being treated by injection or inhalation of antibiotic-laden capsules, saving many lives each year.

Eleanor Porges et al, Antibiotic-Loaded Polymersomes for Clearance of Intracellular Burkholderia thailandensis, ACS Nano (2021). DOI: 10.1021/acsnano.1c05309

https://phys.org/news/2021-11-bacteria-nanoparticles.html?utm_sourc...

Comment by Dr. Krishna Kumari Challa on November 17, 2021 at 9:10am

To understand how the brain enables navigation with and without visual cues, the researchers recorded from neurons across all layers in the retrosplenial cortex as the animals were free to roam around a large arena. This enabled the neuroscientists to identify neurons in the brain called angular head velocity (AHV) cells, which track the speed and direction of the head.

This work  showed that a single cell can see both kinds of signals: vestibular and visual. What was also critically important was the development of a behavioral task that enabled the scientists to determine that mice improve their estimation of their own head angular speed when a visual cue is present. It's pretty compelling that both the coding of head motion and the mouse's estimates of their motion speed both significantly improve when visual cues are available.

 Troy W Margrie, Multi-sensory coding of angular head velocity in the retrosplenial cortex, Neuron (2021). DOI: 10.1016/j.neuron.2021.10.031. www.cell.com/neuron/fulltext/S0896-6273(21)00846-1

https://medicalxpress.com/news/2021-11-neuroscientists-illuminate-b...

Comment by Dr. Krishna Kumari Challa on November 17, 2021 at 9:08am

Neuroscientists illuminate how brain cells 'navigate' in the light and dark

To navigate successfully in an environment, you need to continuously track the speed and direction of your head, even in the dark. Researchers have discovered how individual and networks of cells in an area of the brain called the retrosplenial cortex encode this angular head motion in mice to enable navigation both during the day and at night.

 One of the main aims of this study is to understand how the brain uses external and internal information to tell the difference between allocentric and egocentric-based motion. This paper is the first step in helping us understand whether individual cells  actually have access to both self-motion and, when available, the resultant external visual motion signals.

The researchers found that the retrosplenial cortex uses vestibular signals to encode the speed and direction of the head. However, when the lights are on, the coding of head motion is significantly more accurate.

When the lights are on, visual landmarks are available to better estimate your own speed (at which your head is moving). If you can't very reliably encode your head turning speed, then you very quickly lose your sense of direction. This might explain why, particularly in novel environments, we become much worse at navigating once the lights are turned out.

part 1

Comment by Dr. Krishna Kumari Challa on November 17, 2021 at 8:58am

New gene identified that contributes to progression to type 1 diabetes

When the pro-inflammatory pair, a receptor called CCR2 and its ligand CCL-2, get together, it increases the risk of developing type 1 diabetes, scientists report.

In this autoimmune disease that typically surfaces in childhood, the interaction of this natural lock and key recruits immune cells to the pancreas, which attack the insulin-producing islet cells, resulting in a lifelong course of insulin therapy and a lifelong increased risk of other health problems like heart and kidney disease.

The study, published in the Journal of Translational Autoimmunity, provides evidence the CCR2 gene promotes progression to type 1 as it provides new insight on how to delay disease progression.

The new study focused on 42 individuals who persistently had antibodies against the insulin-producing islet cells but never actually developed type 1, 48 who did develop type 1 and the remainder who did neither and served as the control group.

They found that blood levels of CCL-2, the ligand for CCR2, were lower in both individuals who had antibodies but not actual disease as well as those who progressed to type 1 diabetes.

They also found that both these groups have more of the receptors on their immune cells, which get recruited by the ligand to the six-inch organ in the abdomen that helps us break down the food we eat.

Conversely, less receptors mean less recruitment of immune cells, more normal levels of CCL-2 in the blood and less cell destruction.

Paul MH. Tran et al, The 3p21.31 genetic locus promotes progression to type 1 diabetes through the CCR2/CCL2 pathway, Journal of Translational Autoimmunity (2021). DOI: 10.1016/j.jtauto.2021.100127

https://medicalxpress.com/news/2021-11-gene-contributes-diabetes.ht...

Comment by Dr. Krishna Kumari Challa on November 16, 2021 at 10:04am

Promising candidates for heavy element production are black holes orbited by an accretion disk of dense and hot matter. Such a system is formed both after the merger of two massive neutron stars and during a so-called collapsar, the collapse and subsequent explosion of a rotating star. The internal composition of such accretion disks has so far not been well understood, particularly with respect to the conditions under which an excess of neutrons forms. A high number of neutrons is a basic requirement for the synthesis of heavy elements, as it enables the rapid neutron-capture process or r-process. Nearly massless neutrinos play a key role in this process, as they enable conversion between protons and neutrons.

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The decisive factor is the total mass of the disk. The more massive the disk, the more often neutrons are formed from protons through capture of electrons under emission of neutrinos, and are available for the synthesis of heavy elements by means of the r-process. However, if the mass of the disk is too high, the inverse reaction plays an increased role so that more neutrinos are recaptured by neutrons before they leave the disk. These neutrons are then converted back to protons, which hinders the r-process." As the study shows, the optimal disk mass for prolific production of heavy elements is about 0.01 to 0.1 solar masses. The result provides strong evidence that neutron star mergers producing accretion disks with these exact masses could be the point of origin for a large fraction of the heavy elements. However, whether and how frequently such accretion disks occur in collapsar systems is currently unclear.

In addition to the possible processes of mass ejection, the research group led by Dr. Andreas Bauswein is also investigating the light signals generated by the ejected matter, which will be used to infer the mass and composition of the ejected matter in future observations of colliding neutron stars. An important building block for correctly reading these light signals is accurate knowledge of the masses and other properties of the newly formed elements.

O Just et al, Neutrino absorption and other physics dependencies in neutrino-cooled black hole accretion disks, Monthly Notices of the Royal Astronomical Society (2021). DOI: 10.1093/mnras/stab2861

https://phys.org/news/2021-11-gold-fromnew-insights-element-synthes...

Comment by Dr. Krishna Kumari Challa on November 16, 2021 at 10:04am

Where does gold come from?—New insights into element synthesis in the universe

How are chemical elements produced in our Universe? Where do heavy elements like gold and uranium come from? Using computer simulations, a research team  shows that the synthesis of heavy elements is typical for certain black holes with orbiting matter accumulations, so-called accretion disks.

All heavy elements on Earth today were formed under extreme conditions in astrophysical environments: inside stars, in stellar explosions, and during the collision of neutron stars. Researchers are intrigued with the question in which of these astrophysical events the appropriate conditions for the formation of the heaviest elements, such as gold or uranium, exist. The spectacular first observation of gravitational waves and electromagnetic radiation originating from a neutron star merger in 2017 suggested that many heavy elements can be produced and released in these cosmic collisions. However, the question remains open as to when and why the material is ejected and whether there may be other scenarios in which heavy elements can be produced.

Promising candidates for heavy element production are black holes orbited by an accretion disk of dense and hot matter. Such a system is formed both after the merger of two massive neutron stars and during a so-called collapsar, the collapse and subsequent explosion of a rotating star.

Researchers systematically investigated for the first time the conversion rates of neutrons and protons for a large number of disk configurations by means of elaborate computer simulations, and we found that the disks are very rich in neutrons as long as certain conditions are met

Part 1

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Comment by Dr. Krishna Kumari Challa on November 16, 2021 at 9:59am

Booster shots 

Comment by Dr. Krishna Kumari Challa on November 16, 2021 at 9:46am

Prions may channel RNA's messages

Prions get mostly bad press, but they may be the keys to controlling protein synthesis in cells.

Prions, proteins that can misfold and aggregate, have been implicated in many neurodegenerative diseases. Yet some prions are involved in storing long term memories. New models by  scientists describe how they can regulate the translation of RNA messages into new proteins by forming organized protein synthesis factories.

Vectorial channeling as a mechanism for translational control by functional prions and condensates, Proceedings of the National Academy of Sciences (2021). DOI: 10.1073/pnas.2115904118.

Comment by Dr. Krishna Kumari Challa on November 16, 2021 at 9:39am

In wild populations, diet and geography did influence microbiome composition and diversity.

Diet contributed to natural microbiome structure. The authors collected feces from each rodent at the time of capture to get a snapshot of their diet. Using these samples, they found that animals with more diverse diets had more diverse microbiomes, and animals that fed on similar plants also showed similarities in their microbial communities.

Geography also played a role. The authors found that individuals at the same site had more similar microbiomes, and these communities became more dissimilar as animals were sampled at more distant locations.

However, host relatedness was still the most important factor predicting the microbial makeup of these wild mammals. And these effects only increased when animals were in captivity.

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While every individual experienced a large shift, each individual's microbiome was still closer to its wild self than it would be to any other woodrat species. Researchers didn't see microbiomes merging into the same makeup; species retained distinct bacterial communities. With the differences of diet and habitat removed, they saw even more clearly the extent to which host relatedness influences microbiome structure.

The research team also found that microbiome responses to captivity were species specific, suggesting that host evolutionary history influences not only microbiome structure, but also stability.

Part 2

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