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Comment by Dr. Krishna Kumari Challa on August 25, 2020 at 6:26am

Velcro method for more precise binding of drug particles

In order to deliver drug particles to the right place in the body—a field known as nanomedicine—selectivity plays an important role. After all, the drug only has to attach itself to the cells that need it. A theory from 2011 predicts that selectivity is not only based on the type of receptor, but also on the number and strength of the receptors on the cell. Researchers  are now proving this experimentally.

Cells interact with each other through receptors and ligands. They fit on each other like a key in a lock; a ligand of one cell only fits on the appropriate target receptor of the other cell. The field of nanomedicine makes use of this by imitating ligands that fit the receptors of the diseased cell that needs the drug.

The theory now proven  is based on this: In 2011, Daan Frenkel and his group in Cambridge used a theoretical model to predict that not only the type of ligands and receptors play a major role, but also the number and strength. This means that even weak ligands can bind, as long as there are enough receptors present on the surface of the target cell.

Compare it to Velcro. If one hook is fastened, the strip does not stick immediately. Only when several hooks are fastened does the bond become strong enough. This is also how it works in the human body; the weak binding of a ligand on a receptor becomes enormously strong the more there are.

And that's a useful feature for nanomedicine. Diseased cells do not always have different receptors than healthy cells, but they often have more receptors on their cell walls. By developing the drug in such a way that it only sticks to cells with a lot of receptors, you can still distinguish between diseased and healthy cells. This makes it possible to send the drug particles more precisely to the diseased cells in the body.

It 's now experimentally demonstrated with particles that many weak ligands give a high selectivity: The particles only bind if there are exactly enough receptors present. This creates a threshold value," explains van IJzendoorn. The researchers carried out a binding experiment for this purpose, designing particles with either receptor DNA or ligand DNA on its surface.

A magnetic field first pulled the particles toward each other, and after some time, released them. Van IJzendoorn: "This allowed us to optically measure how many particles had developed a strong molecular binding with each other."

By varying the number of DNA molecules and the strength of the ligand-receptor binding, not only were the researchers able to see how many bindings were needed for the particles to stay bonded, but also to observe the emergence of the  threshold value.

M. R. W. Scheepers el al., Multivalent weak interactions enhance selectivity of interparticle binding, PNAS (2020). www.pnas.org/cgi/doi/10.1073/pnas.2003968117

https://phys.org/news/2020-08-velcro-method-precise-drug-particles....

Comment by Dr. Krishna Kumari Challa on August 25, 2020 at 6:17am

COVID-19 pooling test method identifies asymptomatic carriers

A new COVID-19 pooling test  identifies all positive subjects, including asymptomatic carriers. P-BEST, an algorithmic method for pooling-based efficient SARS-CoV-2 testing, was developed by a group of researchers.

Approximately 10 to 30% of COVID-19-infected patients are asymptomatic and significant viral spread can occur days before symptom onset.

 This new single-stage diagnostic test will help prevent the spread of the disease by identifying these patients sooner and at a lower cost using significantly fewer tests."

https://medicalxpress.com/news/2020-08-covid-pooling-method-asympto...

Noam Shental et al. Efficient high-throughput SARS-CoV-2 testing to detect asymptomatic carriers, Science Advances (2020). DOI: 10.1126/sciadv.abc5961

Comment by Dr. Krishna Kumari Challa on August 25, 2020 at 6:10am

Autistic people's nerve cells differ before birth

Autism is a neurodevelopmental condition that researchers are now tracing back to prenatal development, even though the disorder is not diagnosed until at least 18 months of age. A new study now shows in human brain cells that the atypical development starts at the very earliest stages of brain organization, at the level of individual brain cells.

In a new study researchers used induced pluripotent stem cells, or iPSCs, to model early brain development. Their findings indicate that brain cells from autistic people develop differently to those from typical individuals.

The researchers isolated hair samples from nine autistic people and six typical people. By treating the cells with an array of growth factors, the scientists were able to drive the hair cells to become nerve cells, or neurons—much like those found in either the cortex or the midbrain region. iPSCs retain the genetic identity of the person from which they came and the cells re-start their development as it would have happened in the womb, providing a window into that person's brain development.

At various stages, the authors examined the developing cells' appearance and sequenced their RNA, to see which genes the cells were expressing.

At day 9, developing neurons from typical people formed "neural rosettes," an intricate, dandelion-like shape indicative of typically developing neurons. Cells from autistic people formed smaller rosettes or did not form rosettes at all. And key developmental genes were expressed at lower levels in cells from autistic people.

At days 21 and 35, the cells from typical and autistic people differed significantly in a number of ways, suggesting that the makeup of neurons in the cortex differs in the autistic and typically developing brain.

Dwaipayan Adhya et al, Atypical Neurogenesis in Induced Pluripotent Stem Cells From Autistic Individuals, Biological Psychiatry (2020). DOI: 10.1016/j.biopsych.2020.06.014

https://medicalxpress.com/news/2020-08-autistic-people-nerve-cells-...

Comment by Dr. Krishna Kumari Challa on August 25, 2020 at 6:02am

Biologists discover a gene critical to the development of columbines' iconic spurs

Once in a while, over the history of life, a new trait evolves that leads to an explosion of diversity in a group of organisms. Take wings, for instance. Every group of animals that evolved them has spun off into a host of different species—birds, bats, insects and pterosaurs. Scientists call these "key innovations."

Understanding the development of key innovations is critical to understanding the evolution of the amazing array of organisms on Earth. Most of these happened deep in the distant past, making them difficult to study from a genetic perspective. Fortunately, one group of plants has acquired just such a trait in the past few million years.

Columbines, with their elegant nectar spurs, promise scientists an opportunity to investigate the genetic changes that underpin a key innovation. 

After much research scientists have identified a gene critical to the development of these structures. And to their knowledge, this is among the first key innovations for which a critical developmental gene has been identified and named POPOVICH. 

 Evangeline S. Ballerini el al., "POPOVICH, encoding a C2H2 zinc-finger transcription factor, plays a central role in the development of a key innovation, floral nectar spurs, in Aquilegia," PNAS (2020). www.pnas.org/cgi/doi/10.1073/pnas.2006912117

https://phys.org/news/2020-08-biologists-gene-critical-columbines-i...

Comment by Dr. Krishna Kumari Challa on August 25, 2020 at 5:58am

Scientists think Planet 9 could be a primordial black hole

For several years, astronomers and cosmologists have theorized about the existence of an additional planet with a mass 10 times greater than that of Earth, situated in the outermost regions of the solar system. This hypothetical planet, dubbed Planet 9, could be the source of gravitational effects that would explain the unusual patterns in the orbits of trans-Neptunian objects (TNOs) highlighted by existing cosmological data. TNOs are celestial bodies that orbit the sun and are located beyond Neptune.

Now researchers have recently carried out an investigation exploring the possibility that Planet 9 is a primordial black hole. 

OGLE is a research project carried out at the University of Warsaw that entailed capturing images of the sky using advanced telescopes over long periods of time.

The reanalysis of the OGLE dataset tentatively pointed to the existence of a population of PBHs with a mass similar to what astronomers predicted the mass of Planet 9 would be. When Scholtz and Unwin learned about these tentative findings, they started specifically considering the possibility that Planet 9 may, in fact, be a primordial black hole.

 the researchers showed that one of the previously theorized scenarios for the origin of Planet 9, known as the "capture of a free-floating planet," is just as likely when considered as a scenario involving the capture of a PBH

 What if planet 9 is a primordial black hole? Physical Review Letters (2020). DOI: 10.1103/PhysRevLett.125.051103.

Evidence for a distant giant planet in the solar system. The Astronomical Journal (2020). DOI: 10.3847/0004-6256/151/2/22.

The planet nine hypothesis. Physics Reports (2020). DOI: 10.1016/j.physrep.2019.01.009.

Constraints on Earth-mass primordial black holes from OGLE 5-year microlensing events. Physical Review D (2020). DOI: 10.1103/PhysRevD.99.083503.

https://phys.org/news/2020-08-planet-primordial-black-hole.html?utm...

Comment by Dr. Krishna Kumari Challa on August 24, 2020 at 6:55am

Scientists Just Discovered Another Trick Bacteria Use to Avoid The Immune System

 Infectious bacteria often try their best to stay out of the way of the immune system in our bodies – and scientists have found a surreptitious and previously undiscovered way that they do this.

What happens is that the bacteria release toxins to disarm the mitochondria in immune cells, those tiny organelles that act as the engine rooms of cells. Once the immune cells sense that their mitochondria are inactive, they trigger apoptosis or programmed cell death.

The findings could give us new ways of tackling infectious bacteria, particularly those that have grown resistant to antibiotics – although up to this point, experiments have only been carried out on mice in the laboratory.

"Ironically, it is the activation of host cell death factors that deliver the final blow to mitochondria which induces apoptosis, not the bacterial toxins themselves.

In other words, the bacteria toxins aren't directly killing immune cells, but rather setting in motion a chain of events that causes our body's emergency responders to kill themselves. Our immune cells are using mitochondria as infection sensors.

That was the case in tests on mice described in this study: by targeting genetic controls for apoptosis in the rodents, the scientists were able to reduce inflammation in the animals and lower the risk of infection.

It has been shown in this research work  that we can accelerate the immune response. The other side is that if that response persists and we get constant inflammation – which is usually associated with bacterial infection and which causes a lot of tissue damage – we have a new way to shut down that tissue-damaging inflammation.

Source: https://www.nature.com/articles/s41564-020-0773-2

https://www.sciencealert.com/scientists-have-discovered-another-tri...

Comment by Dr. Krishna Kumari Challa on August 24, 2020 at 6:50am

Guide to Near-light-speed Travel

Comment by Dr. Krishna Kumari Challa on August 24, 2020 at 6:43am

Have you ever seen an atom? See it now!

Comment by Dr. Krishna Kumari Challa on August 24, 2020 at 6:20am

https://theconversation.com/8-ways-the-coronavirus-can-affect-your-...
8 ways the coronavirus can affect your skin, from COVID toes, to rashes and hair loss

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There Are Mysterious Wrinkles Inside Our Hearts. This Might Be What They're For

https://www.sciencealert.com/da-vinci-was-curious-about-the-wrinkle...

Comment by Dr. Krishna Kumari Challa on August 24, 2020 at 6:18am

A new quantum paradox throws the foundations of observed reality into question  

https://theconversation.com/a-new-quantum-paradox-throws-the-founda...  

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