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Comment by Dr. Krishna Kumari Challa on August 19, 2023 at 12:17pm

Why killer bacteria affect some people more severely

Why are certain people more severely affected than others by invasive streptococcal infections? According to a new study the answer lies in our genome. Carriers of a certain variant of the STING gene are at greater risk, particularly if they encounter the bacterial strains that have increased in the western world since the 1980s. The findings, published in Nature Communications, could pave the way for better treatments in cases where disease development is often rapid and fatal.

Group A streptococci are fairly common bacteria that can cause, among other things, strep throat or impetigo. However, if the bacteria become invasive, the situation can become very dangerous. In this case, the name sometimes changes to murder bacteria or flesh-eating bacteria and can give rise to life-threatening conditions such as blood poisoning and septic shock, or soft tissue infections that may make an amputation necessary.

Invasive streptococcal infections have increased in recent decades. The reason for this is not fully understood.

The outcome of infections can vary considerably, and it is still unknown why certain infected individuals develop life-threatening conditions while others don’t.

It depends on an interplay between the genes in people and bacteria.

The researchers’ hypothesis proved to be correct – the genes are different and that affects the risk of developing serious conditions.

The results, published in Nature Communications, provide a molecular explanation of how group A streptococci give rise to tissue-degrading and life-threatening inflammation.

The study also shows how the severity of an infection depends on the interplay between one gene – STING – in our immune system and a bacterial enzyme found in the bacteria that have become more prevalent in the western world since the 1980s. This explains why some people are more severely affected than others.

A person with the ”bad” gene variant of STING has a 20 per cent risk of having a limb amputated in the event of an invasive infection by the worst bacteria. For people with the ”good” gene variant, the risk is only three per cent. The percentage of patients suffering from septic shock also differs depending on the interplay between our STING variants and the bacteria’s enzyme activity.

“The difference is due to a unique combination of genetic material from the host and pathogen. This is partly due to that fact that the immune system of people with a certain variant of the STING gene triggers a misguided and dangerous inflammatory response. The other factor is that the outcome also depends on whether we are infected by the bacteria that are more aggressive because they have a very active variant of the NADase enzyme. Conversely, normal activation of the immune system due to another STING variant and lower bacterial enzyme activity is associated with protection.

The researchers also studied the evolution of the different STING variants in humans. The results show that the risk variant of STING appeared in humans around 35,000 years ago and that it spread to varying degrees around the world in connection with the first agricultural revolution 10,000 years ago. The consequence today is that the risk variant of STING is more common in some parts of the world than others.

https://www.nature.com/articles/s41467-023-39771-0

Comment by Dr. Krishna Kumari Challa on August 19, 2023 at 12:00pm

Researchers discover how stem cells choose their identity

Researchers discovered that stem cells first specialize into a functional cell and then move to their proper location—rather than the other way around. They revealed a new model to show how stem cells specialize into functional cells. They found that their position in the organ is not as important as current models claim. Rather, stem cells choose their identity first and only then move to their appropriate position.

These discoveries were made using intestinal organoids and the new TypeTracker technique, which can now be used to understand other organs at the cellular level and the effects of mutations and medications.

Our intestines contain different types of cells, each of which has a specific task. Just like in many other places in our body, the cells in the intestines are constantly renewed: stem cells develop into specialized cells that perform a function, for example, to secrete substances that protect the intestine or to absorb nutrients from food.

From previous research we know that stem cells reside in the valleys of the intestinal wall (the 'crypts'), while most specialized and functional cells are located at the top of the mountains (the 'villi').

The cells in the intestinal wall are renewed about every week, using the stem cells in the crypts that grow, divide and migrate to the villi. We used to think that by moving upwards to the villus, the stem cells are instructed to become a functional cell. This has been a very appealing model, as it naturally explains how these functional cells are positioned at the right location. However, our data shows a different picture.

This data was obtained using organoids: mini-organs that mimic the original organ so realistically that scientists can use them to unravel its functioning or to test medicines.

The identity of the cells is determined by certain proteins. Stem cells adopted their functional identity much earlier than previously thought. They did so when still deep inside the crypt, before migrating towards the villus region that was thought to provide the trigger to start the specialization process.

Xuan Zheng et al, Organoid cell fate dynamics in space and time, Science Advances (2023). DOI: 10.1126/sciadv.add6480. www.science.org/doi/10.1126/sciadv.add6480

Comment by Dr. Krishna Kumari Challa on August 19, 2023 at 11:47am

Oil eating microbes reshape droplets to optimize biodegradation

 Scientists have found that one kind of oil-eating microbe reshapes droplets to optimize biodegradation. In their study, reported in the journal Science, the group isolated Alcanivorax borkumensis bacteria specimens in a lab setting, fed them crude oil, and then watched how they worked together to eat the oil as quickly and efficiently as possible. 

Prior research has shown that there are many microbes living in the ocean that feed on oil, eventually cleaning away oil not cleaned up by human efforts. Prior research has also shown that such microbes are not able to consume crude oil until it disperses into droplets, which can take a long time. In this new effort, the researchers sought to learn more about the process of crude oil consumption by sea microbes. To that end, they collected A. borkumensis specimens and tested them in their lab.

Under a microscope, the research team observed that A. borkumensis formed biofilms around oil droplets—but they did so in two major ways. In one experiment, A. borkumensis samples that had not been exposed to crude oil before were introduced to simple crude oil droplets. Groups of the bacteria converged on a droplet, forming a sphere. The sphere shape persisted until the entire oil droplet had been consumed.

But when the team exposed samples with experience consuming crude oil, their behavior was much more advanced. Initially, upon converging on a droplet, a sphere formed—but then finger-like protrusions formed, radiating out from the sphere, each completely covered with bacteria. The result was much faster, more efficient consumption of the droplet.

The researchers suggest that the formation of the protrusions results in more oil surface area exposure, allowing more of the bacteria to consume the oil droplet at the same time, compared to the simple sphere, resulting in faster consumption.

M. Prasad et al, Alcanivorax borkumensis biofilms enhance oil degradation by interfacial tubulation, Science (2023). DOI: 10.1126/science.adf3345. www.science.org/doi/10.1126/science.adf3345

Terry J. McGenity et al, Bacteria stretch and bend oil to feed their appetite, Science (2023). DOI: 10.1126/science.adj4430

Comment by Dr. Krishna Kumari Challa on August 19, 2023 at 10:24am

After assessing the local immune response, the researchers examined lung tissues, blood serum, and bronchoalveolar lavage fluid for local and systemic antigen-specific T-cell and antibody responses. Transfection occurred primarily in lung epithelial cells and antigen-presenting cells, two cell types that are relevant targets for pulmonary diseases

The vaccination successfully increased spike protein-specific CD8⁺ T cells in the lung tissue and circulating CD8⁺ T cells in the bloodstream. CD8⁺ T cells expressed markers indicative of tissue-resident memory. Both circulating and mucosal IgG antibodies were found at significantly higher concentrations in vaccinated mice.

Mice were then introduced to a lethal dose of SARS-CoV-2. PACE-mRNA vaccination significantly reduced the viral burden in the lungs and improved the weight and survival of the vaccinated mice. This protection was attributed to the spike protein-specific immune response induced by the vaccination. The control group showed no evidence of a spike protein-specific immune response and did not exhibit reduced viral load or improved survival after the viral challenge. The study presents PACE-mRNA polyplexes as a promising method for efficient and targeted mRNA delivery to the lungs with potential benefits for both therapeutic protein expression and mucosal vaccination against respiratory pathogens.

The study also illustrates the importance of animal models as opposed to cell culture alone in determining real-world effects. The positive results indicate that more research is warranted, with further testing planned on larger animal models.

Alexandra Suberi et al, Polymer nanoparticles deliver mRNA to the lung for mucosal vaccination, Science Translational Medicine (2023). DOI: 10.1126/scitranslmed.abq0603

Part 2

Comment by Dr. Krishna Kumari Challa on August 19, 2023 at 10:22am

Sniffing nanoparticles loaded with mRNA could lead to advanced lung therapeutics

Researchers  have optimized a polymer-based mRNA vehicle for targeted lung delivery and demonstrated the potential of the platform for mucosal vaccination against respiratory pathogens.

In a paper, "Polymer nanoparticles deliver mRNA to the lung for mucosal vaccination," published in Science Translational Medicine, the team introduces their creation of inhalable messenger RNA (mRNA) for therapeutic use.

Clinical research has been searching for an efficient and targeted way to deliver mRNA to the lungs for various therapeutic applications, including protein replacement therapies, gene editing and vaccination. The main challenges have been maintaining mRNA stability and avoiding immune interference.

Researchers now  created PACE (Polymerized Albumin Conjugates for mRNA Encapsulation) polymer formulations to deliver local mRNA to the lungs. The researchers optimized PACE polyplexes to enhance mRNA protection, transfection efficiency, and antigen presentation for effective lung-specific therapeutic and vaccination strategies.

To stabilize PACE, an optimized ratio of polyethylene glycol (PEG) molecules were integrated into the polymer structure during the enzymatic copolymerization process, which stabilized the polyplexes and modified key characteristics. PEG was able to affect the size, surface charge, and other properties of the polyplexes, making them more suitable for loading and effective at mRNA delivery to lung cells.

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The researchers encapsulated mRNA encoding the spike protein from SARS-CoV-2 into PACE and inoculated mice susceptible to SARS-CoV-2 infection. Mice received a 10-μg dose of PACE-mRNA delivered intranasally on days 0 and 28. The development of adaptive immunity in the mediastinal lymph nodes was tested and confirmed 14 days after the boost.

Part 1

Comment by Dr. Krishna Kumari Challa on August 18, 2023 at 8:31am

Climatic changes put the brakes on spider's 'gift-giving'

Being wary of gifts from males of the species takes on a new meaning among a South American spider species known to woo females with silk-wrapped food parcels.

Scientists in South America and Australia have discovered that environmental stresses, such as large variations in rainfall and floods in the rivers, tend to change the mating rituals of these semi-aquatic Neotropical spiders which live in riparian habitats in Uruguay and Brazil.

They found that during moderate to harsh lean times, gift-giving spider Paratrechalea ornata males often offer females a deceptive or worthless gift, rather than a food gift.

This study found this behavior probably corresponds with periods of time when food is more difficult to find so some males might 'cheat' by offering fake gifts.

While males of some spider populations offer prey to females as a way to convince them to mate, there might be less bountiful periods when males are more deceptive with their 'nuptial' gifts.

When local environmental conditions are harsh, these fake parcels become more common rather than the exception and both males and females become smaller and need less food, researchers say, warning of the long-term affects of climate change on spider, insect and other organisms' survival.

In times of plenty, females will usually reject males if they offer fake gifts but they may eventually have to accept the gifts with no food inside when most males are forced to cheat.

Maria J. Albo et al, Stressful environments favor deceptive alternative mating tactics to become dominant, BMC Biology (2023). DOI: 10.1186/s12915-023-01664-5

Comment by Dr. Krishna Kumari Challa on August 18, 2023 at 8:22am

Study discovers pairing of electrons in artificial atoms, a quantum state predicted more than 50 years ago

Researchers observed a quantum state that was theoretically predicted more than 50 years ago by Japanese theoreticians but so far eluded detection. By tailoring an artificial atom on the surface of a superconductor, the researchers succeeded in pairing the electrons of the so-called quantum dot, thereby inducing the smallest possible version of a superconductor. The work appears in the journal Nature.

Usually, electrons repel each other due to their negative charge. This phenomenon has a huge impact on many materials properties such as the electrical resistance. The situation changes drastically if the electrons are "glued" together to pairs thereby becoming bosons. Bosonic pairs do not avoid each other like single electrons, but many of them can reside at the very same location or do the very same motion.

One of the most intriguing properties of a material with such electron pairs is superconductivity, the possibility to let an electrical current flow through the material without any electrical resistance. For many years, superconductivity has found many important technological applications, including magnetic resonance imaging or highly sensitive detectors for magnetic fields.

Today, the continuous downscaling of electronic devices heavily guides investigations on how superconductivity can be induced into much smaller structures at the nanoscale.

Researchers have now realized the pairing of electrons in an artificial atom called quantum dot, which is the smallest building block for nanostructured electronic devices. They locked the electrons into tiny cages that they built from silver, atom-by-atom. By coupling the locked electrons to an elemental superconductor, the electrons inherited the tendency towards pairing from the superconductor.

the researchers related the experimental signature, a spectroscopic peak at very low energy, to the quantum state predicted in the early 1970s by Kazushige Machida and Fumiaki Shibata.

While the state has so far eluded  direct detection by experimental methods, recent work by researchers from the Netherlands and Denmark show it is beneficial for suppressing unwanted noise in transmon qubits, an essential building block of modern quantum computers.

 Lucas Schneider et al, Proximity superconductivity in atom-by-atom crafted quantum dots, Nature (2023). DOI: 10.1038/s41586-023-06312-0

Comment by Dr. Krishna Kumari Challa on August 17, 2023 at 1:55pm

Worms Frozen for 46,000 Years are the Oldest Known Living Animals

Nematodes buried in Siberian permafrost may be able to stay in a state of suspended animation indefinitely, according to recent findings.

Microscopic worms unearthed from Siberian permafrost might belong to a species that went extinct elsewhere on Earth long ago. Researchers said that the tiny, 46,000-year-old nematodes use genes similar to those of their modern-day relatives to enter a state of hibernation where the worms can live indefinitely across tens of thousands of years. The findings were recently published in PLOS Genetics

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Microplastics are adsorbing zinc oxide from sunscreens and microbea...

A new study by a research team from Diamond Light Source looks at how microplastics wastes may interact with zinc oxide (ZnO) nanomaterials in freshwater and seawater scenarios. It also evaluated, a ZnO-based sunscreen and an exfoliating cleanser with microbeads in its composition under the same conditions.

Comment by Dr. Krishna Kumari Challa on August 17, 2023 at 1:53pm

These ‘living’ rocks can give birth to baby stones

The staggering science behind trovants, the rocks that can grow, move – and reproduce.

Trovants are bulbous, otherworldly stones that grow over time, thus appearing to be alive. Parent rocks can even push out baby trovants, which then grow independently.

The sandstone structures are found mainly in Romania, with the most famous cluster in and around a village named Costeşti. There, a Trovants Museum Natural Reserve celebrates and protects them.

The stones’ smooth curves give the appearance of modern, man-made sculptures. They feature heavily in local folklore, with people at one time believing them to be giant dinosaur eggs, plant fossils or alien creations. The word trovant was coined by a naturalist and means cemented sand.

The stones are formed from sand grains or rocks bound together by a limestone – calcium carbonate – cement. Geologists think that the trovants were shaped by earthquakes in the Middle Miocene, over five million years ago.

The stones vary greatly in size and shape, from centimetres to metres in diameter. Whereas most rocks erode and reduce in size over years, trovants continue to expand. During heavy rain, the porous trovants absorb substances, including calcium carbonate from the water. Limestone cement then oozes from the stones to add to their circumference. When water only hits one side of a rock, a blob can emerge, finally breaking free to create a new trovant.

Trovant growth is too slow to be watched in real time. It is estimated that the rocks have only grown a handful of centimetres in over 1,000 years.

The sandstone beds that the stones reside in hint at ancient aquatic environments, with successive sedimentation of material transported by rivers. Indeed, bivalve, and gastropod fossils can sometimes be found hidden inside the trovants.

Source: SF

Comment by Dr. Krishna Kumari Challa on August 17, 2023 at 1:10pm

Cleaning water with 'smart rust' and magnets
Pouring flecks of rust into water usually makes it dirtier. But researchers have developed special iron oxide nanoparticles they call "smart rust" that actually makes it cleaner. Smart rust can attract many substances, including oil, nano- and microplastics, as well as the herbicide glyphosate, depending on the particles' coating. And because the nanoparticles are magnetic, they can easily be removed from water with a magnet along with the pollutants. Now, the team is reporting that they've tweaked the particles to trap estrogen hormones that are potentially harmful to aquatic life.
Using magnetic rust nanoparticles to clean water

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