Scientists reveal how cauliflowers develop their unique shape

 Have you ever wondered how a cauliflower grows into its strange shape? - The mystery of how this peculiar shaped vegetable forms has now been solved by a team of mathematicians and plant scientists.

Now a new study revealed that cauliflowers, and Romanescos in particular, are in fact buds that are designed to become flowers but which never reach their goal. The findings have been published in Science.

The research combines mathematical modelling and plant biology to show that instead of reaching flowering stage cauliflowers develop into stems, which in turn continue trying to produce flowers. The cauliflower is born from this chain reaction, resulting in a succession of stems upon stems.

This study shows that the brief incursion of buds into a flowering state profoundly affects their functioning and allows them, unlike normal stems, to grow without leaves and to multiply almost infinitely. The atypical shape of the Romanesco is explained by the fact that its stems produce buds more and more rapidly (whereas the production rate is constant in other cauliflowers). This acceleration gives each floret a pyramidal appearance, making the fractal aspect of the structure clear. The study highlights how the selection of mutations in plants during the process of domestication has changed their shape, sometimes drastically, into the fruits and vegetables on our shelves.

https://www.nottingham.ac.uk/news/scientists-reveal-how-cauliflower...

Although most plants present a geometric organisation in spirals along main and secondary axes (called "phyllotaxis"), cauliflowers present an unusual phyllotaxis with a multitude of spirals, nested over a wide range of scales. How such a fractal self-similar organization emerges from developmental mechanisms has, until now, remained elusive.

Combining experimental analyses in Arabidopsis thaliana cauliflower-like mutant with mathematical modelling, researchers found that curd self-similarity arises because growing plant tissues fail to form flowers but keep the “memory” of their transient passage in a floral state. Understanding this genetic mutation could help plant scientists optimise growth of related plants.

https://researchnews.cc/news/7684/Scientists-reveal-how-cauliflower...

Scientists Have Created a New Bendy And Flexible Form of Ice

Water ice isn't exactly known for its flexibility. In fact, it's quite the opposite: rigid and brittle, easily fracturing and snapping. It's why avalanches and sea ice fragmentation occur.

It's also why new research is so fascinating. Scientists have just grown microfibers of water ice that can bend in a loop – breaking the previous maximum strain by a significant percentage and opening up new opportunities for the exploration of ice physics.

Ice doesn't always behave the way we expect, and its elasticity – or rather, lack thereof – is a perfect example. Theoretically, it should have a maximum elastic strain of around 15 percent. In the real world, the maximum elastic strain ever measured was less than 0.3 percent. The reason for this discrepancy is that ice crystals have structural imperfections that drive up their brittleness.

So a team of researchers led by nanoscientist Peizhen Xu of Zhejiang University in China sought to create ice with as few structural imperfections as possible.

The experiment consisted of a tungsten needle in an ultracold chamber, sitting at around minus 50 degrees Celsius, much colder than has been previously attempted. Water vapor was released into the chamber, and an electric field was applied. This attracted water molecules to the tip of the needle, where they crystallized, forming a microfiber with a maximum width of around 10 micrometers,  smaller than the width of a human hair.

The next step was to lower the temperature to between minus 70 and minus150 degrees Celsius. Under these low temperatures, the researchers tried bending the ice fibers.

At minus 150 degrees Celsius, they found that a microfiber 4.4 micrometers across was able to bend into a nearly circular shape, with a radius of 20 micrometers. This suggests a maximum elastic strain of 10.9 percent – much closer to the theoretical limit than previous attempts.

Even better, when the researchers released the ice, it sprang back into its previous shape.

https://science.sciencemag.org/content/373/6551/187

https://www.sciencealert.com/scientists-have-created-a-new-bendy-an...

Sulfhemoglobinemia

Heritable Epigenetics: The right combination of parents can turn a gene off indefinitely

Evidence suggests that what happens in one generation—diet, toxin exposure, trauma, fear—can have lasting effects on future generations. Scientists think these effects result from epigenetic changes that occur in response to the environment and turn genes on or off without altering the genome or DNA sequence.

But how these changes are passed down through generations has not been understood, in part, because scientists have not had a simple way to study the phenomenon. A new study by researchers at the University of Maryland provides a potential tool for unraveling the mystery of how experiences can cause inheritable changes to an animal's biology. By mating nematode worms, they produced permanent epigenetic changes that lasted for more than 300 generations. The research was published on July 9, 2021, in the journal Nature Communications.

With their new findings, the researchers now think  some genes could be more vulnerable to permanent epigenetic change while other genes recover within a few generations. Although studies in worms are not the same as in humans, the research provides a window into biological processes that are likely shared, at least in part, by all animals.

"Mating can initiate stable RNA silencing that overcomes epigenetic recovery," Nature Communications (2021). DOI: 10.1038/s41467-021-24053-4

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The research team found while breeding nematode worms that some matings led to epigenetic changes in offspring that continued to be passed down through as many generations as the scientists continued to breed them. This discovery will enable scientists to explore how epigenetic changes are passed to future generations and what characteristics make genes susceptible to permanent epigenetic changes.

They found that there are these RNA-based signals controlling gene expression. Some of these signals silence the gene and some of them are protective signals that prevent silencing. These signals are duking it out as the offspring develop. When the gene comes from the mother, the protective signal always wins, but when the gene comes from the father, the silencing signal almost always wins.

When the silencing signal wins, the gene is silenced for good, or for at least 300 generations, which is how long these researchers followed their laboratory-bred worms. Previous examples of epigenetic changes were more complex or they did not last more than a couple of generations. The researchers don't yet know why the silencing signal only wins some of the time, but this new finding puts them in a much better position to explore the details of epigenetic inheritance than ever before.

While they've found a set of genes that can be silenced almost permanently, most other genes are not affected the same way.

https://phys.org/news/2021-07-combination-parents-gene-indefinitely...

Resistance to last-resort antibiotic may be passing between pet dogs and their owners

The dangerous mcr-1 gene, which provides resistance to the last-resort antibiotic colistin, has been found in four healthy humans and two pet dogs. In two cases, both dog and owner were harbouring the gene, according to new research being presented at the European Congress of Clinical Microbiology & Infectious Diseases (ECCMID) held online this year.

Since first being reported in China in 2015, the mcr-1 gene has been found in various people and animals around the world. It confers resistance to colistin, an antibiotic of last resort used to treat infections from some bacteria resistant to all other antibiotics. The nightmare scenario that could emerge is mcr-1 combining with already drug-resistant bacteria to create a truly untreatable infection.

The study showed that eight dogs out of the 102 pets (7.8%) and four humans out of 126 (3.2%) harboured bacteria with the mcr-1 gene. Three of the dogs were healthy, four had SSTIs and one had a UTI. None of the cats were carrying the gene.

Further analysis showed that the bacteria isolated from all 12 samples that were mcr-1 positive were resistant to multiple antibiotics.

In two households with dogs with SSTIs, the mcr-1 gene was found in both dog and owner. Genetic analysis of the samples suggested that in one of these two cases, the gene had been transmitted between pet and owner.While transmission in both directions is possible, it is thought that in this case the gene passed from dog to human, say the researchers.

The owners did not have infections and so did not need treatment. The sick dogs were successfully treated.

The researchers say their results show that the mcr-1 gene can be transmitted between dogs and their owners. This raises concerns that pets can act as reservoirs of the gene and so aid the spread of resistance to precious last-line antibiotics.

The study was presented at the ongoing European Congress of Clinical Microbiology & Infectious Diseases (ECCMID) taking place online between July 9 and 12.

Source: EUROPEAN SOCIETY OF CLINICAL MICROBIOLOGY AND INFECTIOUS DISEASES

https://medicalxpress.com/news/2021-07-resistance-last-resort-antib...

90-year-old woman infected with UK and South African COVID-19 variants at the same time

Researchers in Belgium report on the case of a 90-year-old woman who was simultaneously infected with two different variants of concern (VOCs) of COVID-19, in a Case Report being presented at the European Congress of Clinical Microbiology & Infectious Diseases (ECCMID) held online this year.

On March 3 2021, the woman, whose medical history was unremarkable, was admitted to the OLV Hospital in the Belgian city of Aalst after a spate of falls. She tested positive for COVID-19 on the same day. She lived alone and received nursing care at home, and had not been vaccinated against COVID-19.

Initially, there were no signs of respiratory distress and the patient had good oxygen saturation. However, she developed rapidly worsening respiratory symptoms, and died five days later.

When the patient's respiratory sample was tested for VOCs with PCR, they discovered that she had been infected by two different strains of the virus—one which originated in the UK, known as B.1.1.7 (Alpha), and another that was first detected in South Africa (B.1.351; Beta).

The presence of both strains was confirmed by PCR on a second respiratory sample, by sequencing of the S-gene and by whole genome sequencing.

"This is one of the first documented cases of co-infection with two SARS-CoV-2 variants of concern.

Both these variants were circulating in Belgium at the time, so it is likely that the lady was co-infected with different viruses from two different people. 

In January 2021, scientists in Brazil reported that two people had been simultaneously infected with two different strains of the coronavirus—the Brazilian variant known as B.1.1.28 (E484K) and a novel variant VUI-NP13L, which had previously been discovered in Rio Grande do Sul. But the study has yet to be published in a scientific journal [1]. Previous research has reported people infected with different influenza strains [2].

Whether the co-infection of the two variants of concern played a role in the fast deterioration of the patient is difficult to say.

 [1] Pervasive transmission of E484K and emergence of VUI-NP13L with evidence of SARS-CoV-2 co-infection events by two different lineages in Rio Grande do Sul, Brazil | medRxiv www.medrxiv.org/content/10.110 … 021.01.21.21249764v1

[2] Natural co-infection of influenza A/H3N2 and A/H1N1pdm09 viruses resulting in a reassortant A/H3N2 virus - ScienceDirect www.sciencedirect.com/science/ … ii/S1386653215007404

ECCMID ABSTRACT 04978: Case report: a 90-year-old lady infected with two CoVID-19 VoCs: 20I/501Y.V1 and 20H/501Y.V2

https://medicalxpress.com/news/2021-07-year-old-woman-infected-uk-s...

Protein appears to prevent tumor cells from spreading via blood vessels

Researchers have identified a specialized protein that appears to help prevent tumor cells from entering the bloodstream and spreading to other parts of the body.

They have discovered that this protein, TRPM7, senses the pressure of fluid flowing in the circulation and stops the cells from spreading through the vascular system. they also found that metastatic tumour  cells have markedly reduced levels of this sensor protein, and that is why they efficiently enter into the circulation rather than turning away from fluid flow.

The findings, published in Science Advances, help shed light on a little-understood part of metastasis called intravasation, when cancer cells that have separated from a primary tumour enter the circulation in order to travel to other parts of the body and establish colonies.

The researchers further show that artificially increasing the expression of TRPM7 in tumor cells may help stop intravasation—and ultimately metastasis—in its tracks.

Christopher L. Yankaskas et al, The fluid shear stress sensor TRPM7 regulates tumor cell intravasation, Science Advances (2021). DOI: 10.1126/sciadv.abh3457

https://medicalxpress.com/news/2021-07-protein-tumor-cells-blood-ve...

Just 25 mega-cities produce 52% of the world's urban greenhouse gas emissions

In 2015, 170 countries worldwide adopted the Paris Agreement, with the goal limiting the average global temperature increase to 1.5°C. Following the agreement, many countries and cities proposed targets for greenhouse gas mitigation. However, the UNEP Emissions Gap Report 2020 shows that, without drastic and strict actions to mitigate the climate crisis, we are still heading for a temperature increase of more than 3°C by the end of the 21st century.

A new study published in the journal Frontiers in Sustainable Cities presents the first global balance sheet of greenhouse gasses (GHGs) emitted by major cities around the world. The aim was to research and monitor the effectiveness of historical GHG reduction policies implemented by 167 globally distributed cities that are at different developmental stages.

While only covering 2% of the Earth's surface, cities are big contributors to the climate crisis. But current urban GHG mitigation targets are not sufficient to achieve global climate change targets by the end of this century. 

The results showed that both developed and developing countries have cities with high total GHG emissions, but that megacities in Asia (such as Shanghai in China and Tokyo in Japan) were especially important emitters. The inventory of per capita emissions showed that cities in Europe, the US, and Australia had significantly higher emissions than most cities in developing countries. China, classified here as a developing country, also had several cities where per capita emissions matched those of developed countries. It is important to note that many developed countries outsource high carbon production chains to China, which increases export-related emissions for the latter.

Restoring touch in nerves damaged by injury

Tel Aviv University's new and groundbreaking technology inspires hope among people who have lost their sense of touch in the nerves of a limb following amputation or injury. The technology involves a tiny sensor that is implanted in the nerve of the injured limb, for example in the finger, and is connected directly to a healthy nerve. Each time the limb touches an object, the sensor is activated and conducts an electric current to the functioning nerve, which recreates the feeling of touch. The researchers emphasize that this is a tested and safe technology that is suited to the human body and could be implanted anywhere inside of it once clinical trials will be done.

The researchers developed a sensor that can be implanted on a damaged nerve under the tip of the finger; the sensor connects to another nerve that functions properly and restores some of the tactile sensation to the finger. This unique development does not require an external power source such as electricity or batteries. The researchers explain that the sensor actually works on frictional force: whenever the device senses friction, it charges itself.

The device consists of two tiny plates less than half a centimeter by half a centimeter in size. When these plates come into contact with each other, they release an electric charge that is transmitted to the undamaged nerve. When the injured finger touches something, the touch releases tension corresponding to the pressure applied to the device—weak tension for a weak touch and strong tension for a strong touch—just like in a normal sense of touch.

The researchers explain that the device can be implanted anywhere in the body where tactile sensation needs to be restored, and that it actually bypasses the damaged sensory organs. Moreover, the device is made from biocompatible material that is safe for use in the human body, it does not require maintenance, the implantation is simple, and the device itself is not externally visible.

Iftach Shlomy et al, Restoring Tactile Sensation Using a Triboelectric Nanogenerator, ACS Nano (2021). DOI: 10.1021/acsnano.0c10141

https://phys.org/news/2021-07-nerves-injury.html?utm_source=nwlette...

Carbon Capture

Researchers unlock behavior of rare cells that evade antibiotics by 'playing dead'

Researchers have developed a new microfluidic platform to track a very rare type of cell that can survive antibiotic treatments. The results have important implications for microbiologists learning about the cellular control of bacterial physiology and for scientists looking to combat the emerging threat of antibiotic resistance bacteria that can lead to untreatable infections.

"Persister cells" are a very small subpopulation of cells that survive antibiotic treatment by staying dormant and then resume growth after the antibiotic has been removed. These cells are transient and are therefore harder to study and have no genetic changes, meaning that they cannot be identified using sequencing.

Since these "persister cells" are both rare and transient, a platform is needed to image cells over time with sufficiently large throughput. Now researchers from the University of Cambridge, Harvard Medical School and Harvard University have developed a platform designed to track more than 100,000 individual bacterial cells over hundreds of generations as they experience rounds of feast-and-famine cycles. An array of hundreds of thousands of traps are used to keep individual cells immobilized and infused with the contents from a growing culture—E. coli (Escherichia coli), normally found in the intestine, and Bacillus subtilis, commonly found in soil. A high-resolution microscope rapidly scans over each cell and tracks their fate over time. The results are reported in the journal Nature Microbiology.

Somenath Bakshi et al, Tracking bacterial lineages in complex and dynamic environments with applications for growth control and persistence, Nature Microbiology (2021). DOI: 10.1038/s41564-021-00900-4

https://phys.org/news/2021-07-behavior-rare-cells-evade-antibiotics...

Sex-specific immune response in COVID-19 linked to cellular metabolism

 Researchers studying COVID-19 patients have found a metabolic pathway that is highly correlated with immune responses only in male patients, a group known to be more likely to suffer severe cases and die of the disease, representing a potential target for therapeutic intervention. In a study published in the journal Science Signaling, the authors report that male COVID-19 patients were more likely than female patients or healthy control subjects to have elevated levels of kynurenic acid, a product of amino acid metabolism. High levels of kynurenic acid have been linked to several diseases, such as schizophrenia and HIV-related diseases. Male patients with severe COVID-19 cases were also more likely to have a high ratio of kynurenic acid to kynurenine, a byproduct of the amino acid L-tryptophan which is used to create the nutrient niacin. We know that men are at higher risk than women of contracting severe cases of COVID-19 and that sex differences in the body's immune responses  present a compelling explanation for this phenomenon.

We also know that immune responses are regulated in part by metabolites, and so these new findings offer a key window into the mechanisms underlying how this disease affects female and male patients differently

https://researchnews.cc/news/7739/Sex-specific-immune-response-in-C...

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The World's Most Dangerous Blood Type

Electric signals between individual cardiac cells regulate heartbeat

The rhythm in a working heart is regulated by electrical impulses. Disturbances of this bioelectrical process can result in cardiac arrhythmias, or irregularities in heartbeat—a common ailment that can lead to illness and death.

In Biophysics Reviews, researchers from Harvard Medical School provide a state-of-the-art update on how electrical impulses in the heart travel from cell to cell.

A functioning heart contracts to pump blood to the body and the lungs. Within the heart, a pacemaker acts as an electrical clock, sending out a signal that tells the heart when to contract. The whole muscle moves together, because each individual cell inside of it contracts in a coordinated manner and within a short time interval.

In order to do so, the initial electrical impulse, sent by the pacemaker, rapidly spreads through cells across the heart.

If one cell is excited electrically and the other is not, the excited cell becomes positively charged inside, and the resting cell is still negatively charged inside. As a consequence, a voltage gradient builds up between the cells. If you have a voltage gradient and a pathway with a low electrical resistance, a local current will flow.

The connections between cells forming the low resistance pathway and facilitating the current flow are called gap junctions. Each consists of many channels, which are formed when specific proteins from one cell dock and fuse to the proteins from another cell. Kléber said the fusing proteins look like placing the tips of your fingers on one hand to the fingers on the other hand.

The scientists delve into the properties of gap junctions and their constituent proteins, the so-called connexins. Kléber said one reason gap junction channels are interesting is because they are a highly dynamic system in equilibrium. The creation, or synthesis, of the channels equals the destruction.

"The turnover is very short," he said. "On one hand, the system is very stable during your whole life. On the other hand, if you measure it, it is constantly cycling in periods of a few hours."

The proteins found in gap junctions are important for processes not directly related to cell-cell connections, like mitochondrial function which creates energy, and trafficking, which transports molecules from the site of synthesis to their site of action in the cell interior.

You have to refrain from the idea that if you define the role of a protein in the body, that it has only a single function.

"Coupling between cardiac cells - an important determinant of electrical impulse propagation and arrhythmogenesis" Biophysics Reviews, aip.scitation.org/doi/10.1063/5.0050192

https://medicalxpress.com/news/2021-07-electric-individual-cardiac-...

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Are silver nanoparticles a silver bullet against microbes?

Antimicrobials are used to kill or slow the growth of bacteria, viruses and other microorganisms. They can be in the form of antibiotics, used to treat bodily infections, or as an additive or coating on commercial products used to keep germs at bay. These life-saving tools are essential to preventing and treating infections in humans, animals and plants, but they also pose a global threat to public health when microorganisms develop resistance to them, a concept known as antimicrobial resistance.

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Tree rings show record of newly identified extreme solar activity e...

The sun constantly emits a stream of energetic particles, some of which reach Earth. The density and energy of this stream form the basis of space weather, which can interfere with the operation of satellites and other spacecraft. A key unresolved question in the field is the frequency with which the sun emits bursts of energetic particles strong enough to disable or destroy space-based electronics.

Tree rings show record of newly identified extreme solar activity event

The sun constantly emits a stream of energetic particles, some of which reach Earth. The density and energy of this stream form the basis of space weather, which can interfere with the operation of satellites and other spacecraft. A key unresolved question in the field is the frequency with which the sun emits bursts of energetic particles strong enough to disable or destroy space-based electronics.

One promising avenue for determining the rate of such events is the dendrochronological record. This approach relies on the process by which a solar energetic particle (SEP) strikes the atmosphere, causing a chain reaction that results in the production of an atom of carbon-14. This atom subsequently can be incorporated into the structure of a tree; thus, the concentration of carbon-14 atoms in a tree ring can indicate the impact rate of SEPs in a given year.

To date, three events of extreme SEP production are well described in literature, occurring approximately in the years 660 BCE, 774–775 CE, and 992–993 CE. Each event was roughly an order of magnitude stronger than any measured in the space exploration era. Miyake et al. describe such an event, which occurred between 5411 BCE and 5410 BCE. Because of this burst, atmospheric carbon-14 increased 0.6 percent year over year in the Northern Hemisphere and was sustained for several years before dropping to typical levels.

Using statistical methods, the researchers identified a pattern of small carbon-14 fluctuations consistent with the sun's 11-year solar cycle; the event recorded in the tree ring occurred during a time of solar maximum. Notably, other evidence suggests that the sun was also undergoing a decades-long period of increasing activity.

If an extreme SEP burst is indeed the cause of the additional carbon-14, then these observations could aid in forecasting future events. However, tree ring  measurements cannot rule out other extraterrestrial causes, such as a nearby supernova explosion. Confirmation will require isotopic measurements of beryllium and chlorine taken from ice cores, according to the authors.

F. Miyake et al, A Single‐Year Cosmic Ray Event at 5410 BCE Registered in 14 C of Tree Rings, Geophysical Research Letters (2021). DOI: 10.1029/2021GL093419

https://phys.org/news/2021-07-tree-newly-extreme-solar-event.html?u...

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Gene editing 'blocks virus transmission' in human cells

Scientists have used CRISPR gene-editing technology to successfully block the transmission of the SARS-CoV-2 virus in infected human cells, according to research released recently that could pave the way for COVID-19 treatments.

Writing in the journal Nature Communications, researchers in Australia said the tool was effective against viral transmissions in lab tests, adding that they hoped to begin animal trials soon.

CRISPR, which allows scientists to alter DNA sequences and modify gene function, has already shown promise in eliminating the genetic coding that drives the development of children's cancer.

The team in Tuesday's study used an enzyme, CRISPR-Cas13b, that binds to relevant RNA sequences on the novel coronavirus and degrades the genome it needs to replicate inside human cells.

 The team had designed the CRISPR tool to recognize SARS-CoV-2, the virus responsibly for COVID-19.

Once the virus is recognized, the CRISPR enzyme is activated and chops up the virus.

Mohamed Fareh et al, Reprogrammed CRISPR-Cas13b suppresses SARS-CoV-2 replication and circumvents its mutational escape through mismatch tolerance, Nature Communications (2021). DOI: 10.1038/s41467-021-24577-9

https://phys.org/news/2021-07-gene-blocks-virus-transmission-human....

Quantum physics helps destroy cancer cells

Cancer cell death is triggered within three days when X-rays are focused on tumor tissue containing iodine-carrying nanoparticles. The iodine releases electrons that break the tumor's DNA, leading to cell death.

Exposing a metal to light leads to the release of electrons, a phenomenon called the photoelectric effect. An explanation of this phenomenon by Albert Einstein in 1905 heralded the birth of quantum physics. This research now research provides evidence that suggests it is possible to reproduce this effect inside cancer cells.

A longstanding problem with cancer radiation therapy is that it is not effective at the center of tumors, where oxygen levels are low due to the lack of deep-penetrating blood vessels. X-ray irradiation needs oxygen to generate DNA-damaging reactive oxygen when the rays hit molecules inside the cell.

Researchers have been trying to overcome this issue by finding more direct ways to damage cancer DNA. In earlier work, they showed that gadolinium-loaded nanoparticles could kill cancer cells when irradiated with 50.25 kiloelectron volts of synchrotron-generated X-rays.

In the current study, they designed porous, iodine-carrying organosilica nanoparticles. Iodine is cheaper than gadolinium and releases electrons at lower energy levels.

The researchers dispersed their nanoparticles through tumor spheroids, 3D tissue containing multiple cancer cells. Irradiating the spheroids for 30 minutes with 33.2 keV of X-rays led to their complete destruction within three days. By systematically changing energy levels, they were able to demonstrate that the optimum effect of tumor destruction occurs with 33.2 keV X-ray. Further analyses showed that the nanoparticles were taken up by the tumor cells, localizing just outside their nuclei. Shining just the right amount of X-ray energy onto the tissue prompted iodine to release electrons, which then caused double-strand breaks in the nuclear DNA, triggering cell death. 

Yuya Higashi et al, Iodine containing porous organosilica nanoparticles trigger tumor spheroids destruction upon monochromatic X-ray irradiation: DNA breaks and K-edge energy X-ray, Scientific Reports (2021). DOI: 10.1038/s41598-021-93429-9

https://phys.org/news/2021-07-quantum-physics-cancer-cells.html?utm...

New spray could someday help heal damage after a heart attack

Heart attack, or myocardial infarction, is one of the leading causes of death worldwide. Although modern surgical techniques, diagnostics and medications have greatly improved early survival from these events, many patients struggle with the long-term effects of permanently damaged tissue, and the 5-year mortality rate remains high. Now, researchers reporting in ACS Nano have developed a minimally invasive exosome spray that helped repair rat hearts after myocardial infarction.

The Story of Primary Plastid Endosymbiosis: How Algae and Plants became Photosynthetic

Glass octopus moving in the deep sea

Marine biologists spotted the elusive glass octopus (Vitreledonella richardi) during a 34-day expedition off the remote Phoenix Islands

Human cells harness power of detergents to wipe out bacteria

This killer cleaner, a protein known as APOL3, thwarts infections by dissolving bacterial membranes. Researchers tested the protein on the food-poisoning bacteria Salmonella and other similar microbes.

The work offers new insight into how human cells defend themselves against infection, a process termed cell-autonomous immunity. While scientists knew that cells could attack bacterial membranes, this study uncovers what appears to be the first example of a protective intracellular protein with detergent-like action.

"A human apolipoprotein L with detergent-like activity kills intracellular pathogens" Science (2021). science.sciencemag.org/cgi/doi … 1126/science.abf8113

https://phys.org/news/2021-07-human-cells-harness-power-detergents....

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Thinking without a brain: Studies in brainless slime molds reveal that they use physical cues to decide where to grow

Scientists  have discovered that a brainless slime mold called Physarum polycephalum uses its body to sense mechanical cues in its surrounding environment, and performs computations similar to what we call "thinking" to decide in which direction to grow based on that information. Unlike previous studies with Physarum, these results were obtained without giving the organism any food or chemical signals to influence its behavior. The study is published in Advanced Materials.

Physarum is interesting because it doesn't have a brain but it can still perform a lot of the behaviours that we associate with thinking, like solving mazes, learning new things, and predicting events. Figuring out how proto-intelligent life manages to do this type of computation gives us more insight into the underpinnings of animal cognition and behavior, including our own.

The team's research demonstrated that this brainless creature was not simply growing toward the heaviest thing it could sense—it was making a calculated decision about where to grow based on the relative patterns of strain it detected in its environment.

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Slime molds are amoeba-like organisms that can grow to be up to several feet long, and help break down decomposing matter in the environment like rotting logs, mulch, and dead leaves. A single Physarum creature consists of a membrane containing many cellular nuclei floating within a shared cytoplasm, creating a structure called a syncytium. Physarum moves by shuttling its watery cytoplasm back and forth throughout the entire length of its body in regular waves, a unique process known as shuttle streaming. With most animals, we can't see what's changing inside the brain as the animal makes decisions. Physarum offers a really exciting scientific opportunity because we can observe its decisions about where to move in real-time by watching how its shuttle streaming behavior changes.

While previous studies have shown that Physarum moves in response to chemicals and light, Murugan and her team wanted to know if it could make decisions about where to move based on physical cues in its environment alone.

The researchers placed Physarum specimens in the center of petri dishes coated with a semi-flexible agar gel and placed either one or three small glass discs next to each other atop the gel on opposite sides of each dish. They then allowed the organisms to grow freely in the dark over the course of 24 hours, and tracked their growth patterns. For the first 12 to 14 hours, the Physarum grew outwards evenly in all directions; after that, however, the specimens extended a long branch that grew directly over the surface of the gel toward the three-disc region 70% of the time. Remarkably, the Physarum chose to grow toward the greater mass without first physically exploring the area to confirm that it did indeed contain the larger object.

Part 2: 

The researchers experimented with several variables to see how they impacted Physarum's growth decisions, and noticed something unusual: when they stacked the same three discs on top of each other, the organism seemed to lose its ability to distinguish between the three discs and the single disc. It grew toward both sides of the dish at roughly equal rates, despite the fact that the three stacked discs still had greater mass. Clearly, Physarum was using another factor beyond mass to decide where to grow.

To figure out the missing piece of the puzzle, the scientists used computer modeling to create a simulation of their experiment to explore how changing the mass of the discs would impact the amount of stress (force) and strain (deformation) applied to the semi-flexible gel and the attached growing Physarum. As they expected, larger masses increased the amount of strain, but the simulation revealed that the strain patterns the masses produced changed, depending on the arrangement of the discs.

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But how was it detecting these strain patterns? The scientists suspected it had to do with Physarum's ability to rhythmically contract and tug on its substrate, because the pulsing and sensing of the resultant changes in substrate deformation allows the organism to gain information about its surroundings. 

Advanced Materials (2021). DOI: 10.1002/adma.202008161

https://phys.org/news/2021-07-brain-brainless-slime-molds-reveal.ht...

Researchers create snake-venom-derived 'super glue' that stops bleeding in seconds 

This super glue is based on a new discovery on a blood clotting enzyme called reptilase or batroxobin found in the venom of lancehead snakes (Bothrops atrox), which are amongst the most poisonous snakes in South America.

Taking advantage of this clotting property, researchers designed a body tissue adhesive that incorporates the special enzyme into a modified gelatin that can be packaged into a small tube for easy, and potentially life-saving, application.

During trauma, injury and emergency bleeding, this 'super glue' can be applied by simply squeezing the tube and shining a visible light, such as a laser pointer, over it for few seconds. Even a smartphone flashlight will do the job.

Compared to clinical fibrin glue, considered the industry gold standard for clinical and field surgeons, the new tissue sealant has 10 times the adhesive strength to resist detachment or washout due to bleeding. The blood clotting time is also much shorter, cutting it in half from 90 seconds for fibrin glue to 45 seconds for the new snake venom "super glue."

This new biotechnology translates to less blood loss and more life-saving. The super-sealant was tested in models for deep skin cuts, ruptured aortae, and severely injured livers—all considered as major bleeding situations.

Yicheng Guo et al, Snake extract–laden hemostatic bioadhesive gel cross-linked by visible light, Science Advances (2021). DOI: 10.1126/sciadv.abf9635

https://phys.org/news/2021-07-snake-venom-derived-super-seconds-vis...

Researchers confirm we may never know how many species have inhabit...

Professors in Syracuse University's College of Arts and Sciences explored whether or not the scientific community will ever be able to settle on a 'total number' of species of living vertebrates, which could help with species preservation. By knowing what's out there, researchers argue that they can prioritize places and groups on which to concentrate conservation efforts.

Bruce H Wilkinson et al, Estimating vertebrate biodiversity using the tempo of taxonomy – a view from Hubbert's peak, Biological Journal of the Linnean Society (2021). DOI: 10.1093/biolinnean/blab080

‘Super-antibodies’ could curb COVID-19 and help avert future pandemics

Companies are designing next-generation antibodies modeled on those taken from unique individuals whose immune systems can neutralize any COVID-19 variant—and related coronaviruses, too.

A new generation of designer antibodies could help to treat a wide range of SARS-CoV-2 variants — and future coronaviruses with pandemic potential. ‘Super-antibodies’ are modelled on antibodies taken from rare individuals whose immune systems can neutralize any SARS-CoV-2 variant and related coronaviruses.

https://www.nature.com/articles/s41587-021-00980-x?utm_source=Natur...

Just 7% of our DNA is unique to modern humans, study shows

What makes humans unique? Scientists have taken another step toward solving an enduring mystery with a new tool that may allow for more precise comparisons between the DNA of modern humans and that of our extinct ancestors.

Just 7% of our genome is uniquely shared with other humans, and not shared by other early ancestors, according to a study published Friday in the journal Science Advances.

That's a pretty small percentage. This kind of finding is why scientists are turning away from thinking that we humans are so vastly different from Neanderthals.

The research draws upon DNA extracted from fossil remains of now-extinct Neanderthals and Denisovans dating back to around 40,000 or 50,000 years ago, as well as from 279 modern people from around the world.

Scientists already know that modern people share some DNA with Neanderthals, but different people share different parts of the genome. One goal of the new research was to identify the genes that are exclusive to modern humans.

It's a difficult statistical problem, and the researchers developed a valuable tool that takes account of missing data in the ancient genomes.

The researchers also found that an even smaller fraction of our genome—just 1.5%—is both unique to our species and shared among all people alive today. Those slivers of DNA may hold the most significant clues as to what truly distinguishes modern human beings.

Scientists now can tell those regions of the genome are highly enriched for genes that have to do with neural development and brain function.

Nathan K. Schaefer et al, An ancestral recombination graph of human, Neanderthal, and Denisovan genomes, Science Advances (2021). DOI: 10.1126/sciadv.abc0776

https://phys.org/news/2021-07-dna-unique-modern-humans.html?utm_sou...

Common medication used to reduce cholesterol levels may reduce COVID-19 severity

In a new study, researchers have confirmed that patients taking statin medications had a 41 percent lower risk of in-hospital death from COVID-19. The findings were published July 15, 2021 in PLOS ONE.

Statins are commonly used to reduce blood cholesterol levels by blocking liver enzymes responsible for making cholesterol. They are widely prescribed.

When faced with this virus at the beginning of the pandemic, there was a lot of speculation surrounding certain medications that affect the body's ACE2 receptor, including statins, and whether they may influence COVID-19 risk. At the time, scientists thought that statins may inhibit SARS-CoV-2 infection through their known anti-inflammatory effects and binding capabilities, which could potentially stop progression of the virus.

Researchers now analyzed anonymized medical records of 10,541 patients admitted for COVID-19 over a nine-month period, January through September 2020, at 104 different hospitals.

From this data, they performed more advanced analyses as they attempted to control for coexisting medical conditions, socioeconomic status and hospital factors. In doing so, they confirmed their prior findings that statins are associated with a reduced risk of death from COVID-19 among patients hospitalized for COVID-19.

It appears most of the benefit is among patients with good medical reasons to be taking statins, such as a history of cardiovascular disease or high blood pressure. According to the research team, the use of statins or an anti-hypertension medication was associated with a 32 percent lower risk of death among COVID-19 inpatients with a history of cardiovascular disease or hypertension.

In the study, statistical matching techniques were used to compare outcomes for patients who used statins or an anti-hypertension medication with similar patients who did not.

The ACE2 receptor—the regulatory target of statins—helps control blood pressure. In 2020, it was discovered that SARS-CoV-2 virus primarily uses the same receptor to enter lung cells.

According to researchers, statins and anti-hypertension medications stabilize the underlying diseases for which they are prescribed, making patients more likely to recover from COVID-19.

As with any observational study, researchers cannot say for certain that the associations  they describe between statin use and reduced severity of COVID-19 infection are definitely due to the statins themselves; however, they can now say with very strong evidence that they may play a role in substantially lowering a patient's risk of death from COVID-19. 

Lori B. Daniels et al, Relation of prior statin and anti-hypertensive use to severity of disease among patients hospitalized with COVID-19: Findings from the American Heart Association's COVID-19 Cardiovascular Disease Registry, PLOS ONE (2021). DOI: 10.1371/journal.pone.0254635

https://medicalxpress.com/news/2021-07-common-medication-cholestero...

Antibiotics in early life could affect brain development

Antibiotic exposure early in life could alter human brain development in areas responsible for cognitive and emotional functions, according to  some researchers. The laboratory study, published in the journal iScience, suggests that penicillin changes the microbiome the trillions of beneficial microorganisms that live in and on our bodies  as well as gene expression, which allows cells to respond to its changing environment, in key areas of the developing brain. The findings suggest reducing widespread antibiotic use or using alternatives when possible to prevent neurodevelopment problems. Penicillin and related medicines (like ampicillin and amoxicillin) are the most widely used antibiotics in children worldwide.

Previous work has shown that exposing young animals to antibiotics changes their metabolism and immunity. The third important development in early life involves the brain. This study is preliminary but shows a correlation between altering the microbiome and changes in the brain that should be further explored.

The study compared mice that were exposed to low-dose penicillin in utero or immediately after birth to those that were not exposed. They found that mice given penicillin experienced substantial changes in their intestinal microbiota and had altered gene expression in the frontal cortex and amygdala, two key areas in the brain responsible for the development of memory as well as fear and stress responses.

A growing body of evidence links phenomena in the intestinal tract with signaling to the brain, a field of study known as the “gut-brain-axis.” If this pathway is disturbed, it can lead to permanent altering of the brain’s structure and function and possibly lead to neuropsychiatric or neurodegenerative disorders in later childhood or adulthood.

1. Angelina Volkova, Kelly Ruggles, Anjelique Schulfer, Zhan Gao, Stephen D. Ginsberg, Martin J. Blaser. Effects of early-life penicillin exposure on the gut microbiome and frontal cortex and amygdala gene expression. iScience, 2021; 102797 DOI: 10.1016/j.isci.2021.102797

https://researchnews.cc/news/7831/Antibiotics-in-early-life-could-a...

The world's thinnest technology-only two atoms thick

Long COVID Has Over 200 Symptoms!

A new study has identified 203 different long COVID symptoms across 10 different organ systems in the body, highlighting just how widespread and varied the affliction is and how it can interfere with many different aspects of daily life.

With a total of 3,762 people quizzed across 56 countries, the international study is the biggest and most comprehensive look yet at how 'long haulers' continue to have problems way beyond the normal timescale of COVID-19.

The most commonly reported symptoms were fatigue, post-exertional malaise (symptoms getting worse after physical or mental effort), and cognitive dysfunction or 'brain fog'. Other symptoms included visual hallucinations, tremors, sexual dysfunction, memory loss, and diarrhea – a whole range of physical and cognitive health issues.

On average, participants reported 55.9 symptoms each, across 9.1 organ systems. Of the 3,762 respondents with long COVID, 2,454 had experienced symptoms for at least six months. All that takes a toll: 45.2 percent of participants said they had reduced their working hours, while 22.3 percent were not working at all at the time of the survey.

"By seven months, many patients have not yet recovered (mainly from systemic and neurological/cognitive symptoms), have not returned to previous levels of work, and continue to experience significant symptom burden," write the researchers in their published paper.

https://www.thelancet.com/journals/eclinm/article/PIIS2589-5370(21)00299-6/fulltext

Common COVID-19 antibiotic no more effective than placebo

 A new study has found that the antibiotic azithromycin was no more effective than a placebo in preventing symptoms of COVID-19 among non-hospitalized patients, and may increase their chance of hospitalization, despite widespread prescription of the antibiotic for the disease.

https://jamanetwork.com/journals/jama/fullarticle/2782166

https://researchnews.cc/news/7855/Common-COVID-19-antibiotic-no-mor...

These findings do not support the routine use of azithromycin for outpatient SARS-CoV-2 infection.

Azithromycin, a broad-spectrum antibiotic, is widely prescribed as a treatment for COVID-19 in the United States and the rest of the world. The hypothesis is that it has anti-inflammatory properties that may help prevent progression if treated early in the disease. But this was found to be untrue.

The study was published in the Journal of the American Medical Association

Global satellite data shows clouds will amplify global heating

A new approach to analyze satellite measurements of Earth's cloud cover reveals that clouds are very likely to enhance global heating.

The research is the strongest evidence yet that clouds will amplify global heating over the long term, further exacerbating climate change.

It also suggest that at double atmospheric carbon dioxide (CO₂) concentrations above pre-industrial levels, the climate is unlikely to warm below 2°C, and is more likely on average to warm more than 3°C.

Pre-industrial CO₂ levels were around 280 ppm (parts per million), but current levels are approaching 420 ppm, and could approach double the pre-industrial amount by mid-century if significant emissions cuts are not made. The amount of climate warming predicted from a doubling of pre-industrial CO₂ levels is known as the 'climate sensitivity' - a measure of how strongly our climate will react to such a change.

The largest uncertainty in climate sensitivity predictions is the influence of clouds, and how they may change in the future. This is because clouds, depending on properties such as their density and height in the atmosphere, can either enhance or dampen warming.

Low clouds tend to have a cooling effect, as they block the sun from reaching the ground. High clouds, however, have a warming effect, as while they let solar energy reach the ground, the energy emitted back from the Earth is different. This energy can be trapped by the clouds, enhancing the greenhouse effect. Therefore, the type and amount of cloud a warming world will produce impacts further warming potential.

Paulo Ceppi el al., "Observational evidence that cloud feedback amplifies global warming," PNAS (2021). www.pnas.org/cgi/doi/10.1073/pnas.2026290118

https://phys.org/news/2021-07-global-satellite-clouds-amplify.html?...

Massive DNA 'borg' structures perplex scientists

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An exciting career pathway for connecting Science to the Masses

CSIR‐NISCAIR offers doctoral degree and post graduate courses in Science & Technology Communication

http://niscair.res.in/researchandeducation/acsir

NASA Lucy mission's message to the future

In the 1970s four spacecraft began their one-way trips out of our Solar System. As the first human-built objects to ever venture into interstellar space, NASA chose to place plaques on Pioneer 10 and 11 and golden records on Voyager 1 and 2 spacecraft to serve as messages to any alien spacefarers that may someday encounter these spacecraft. Continuing this legacy, NASA's Lucy spacecraft will carry a similar plaque. However, because Lucy will not be venturing outside of our Solar System, Lucy's plaque is a time-capsule featuring messages to our descendants.

No more broken mobile screens: Bengal researchers develop self-healing material

Common Medication Used to Reduce Cholesterol Levels May Reduce COVI... (UCSD Health, 7/15/21)

Common cholesterol drugs statins may lower death risk from COVID-19 (Seeking Alpha, 7/19/21)

Scientists create world's thinnest magnet

The development of an ultrathin magnet that operates at room temperature could lead to new applications in computing and electronics—such as high-density, compact spintronic memory devices—and new tools for the study of quantum physics.

The ultrathin magnet, which was recently reported in the journal Nature Communications , could make big advances in next-gen memories, computing, spintronics, and quantum physics.

This discovery is exciting because it not only makes 2-D magnetismpossible at room temperature, but it also uncovers a new mechanism to realize 2-D magnetic materials.

zinc oxide's free electrons could act as an intermediary that ensures the magnetic cobalt atoms in the new 2-D device continue pointing in the same direction—and thus stay magnetic—even when the host, in this case the semiconductor zinc oxide, is a nonmagnetic material.

Rui Chen et al, Tunable room-temperature ferromagnetism in Co-doped two-dimensional van der Waals ZnO, Nature Communications (2021). DOI: 10.1038/s41467-021-24247-w

https://phys.org/news/2021-07-scientists-world-thinnest-magnet.html...

The Standard Model

Quantum Computers, Explained With Quantum Physics

Microbially produced fibers: Stronger than steel, tougher than Kevlar

Spider silk is said to be one of the strongest, toughest materials on the Earth. Now engineers  have designed amyloid silk hybrid proteins and produced them in engineered bacteria. The resulting fibers are stronger and tougher than some natural spider silks.

The artificial silk—dubbed "polymeric amyloid" fiber—was not technically produced by researchers, but by bacteria that were genetically engineered in the lab.

Jingyao Li et al, Microbially Synthesized Polymeric Amyloid Fiber Promotes β-Nanocrystal Formation and Displays Gigapascal Tensile Strength, ACS Nano (2021). DOI: 10.1021/acsnano.1c02944

https://phys.org/news/2021-07-microbially-fibers-stronger-steel-tou...

Study finds calcium precisely directs blood flow in the brain

Unlike the rest of the body, there is not enough real estate in the brain for stored energy. Instead, the brain relies on the hundreds of miles of blood vessels within it to supply fresh energy via the blood. Yet, how the brain expresses a need for more energy during increased activity and then directs its blood supply to specific hot spots was, until now, poorly understood.

Now,  researchers have shown how the brain communicates to blood vessels when in need of energy, and how these blood vessels respond by relaxing or constricting to direct blood flow to specific brain regions.

If the brain does not get blood to where it needs it when it needs it, the neurons become stressed, and over time they deteriorate ultimately leading to cognitive decline and memory problems.

Large arteries feed medium-sized vessels known as arterioles that then feed even tinier capillaries—so small that only a single blood cell can pass through at once. In a 2017 Nature Neuroscience paper, the researchers showed that electrical pulses coursing through the capillaries direct blood flow from the medium-sized arterioles supplying large regions of the brain. For this latest paper, the team studied the fine-tuning of blood as it flows through the capillaries to precisely regulate energy supply to tiny regions in the brain.

There seem to be two mechanisms working in tandem to ensure that energy in the form of blood makes it to specific regions of the brain: one broad and the other precise. The first electrical mechanism is like a crude sledgehammer approach to get more blood to the general vicinity of the increased brain activity by controlling the medium-sized arterioles, and then capillary calcium signals ensure exquisite fine-tuning to make sure the blood gets to exactly the right place at the right time through the tiny capillaries.

"Local IP3 receptor–mediated Ca2+ signals compound to direct blood flow in brain capillaries" Science Advances (2021). advances.sciencemag.org/lookup … .1126/sciadv.abh0101

https://medicalxpress.com/news/2021-07-calcium-precisely-blood-brai...

Rounding errors could make certain stopwatches pick wrong race winners

As the Summer Olympics draw near, the world will shift its focus to photo finishes and races determined by mere fractions of a second. Obtaining such split-second measurements relies on faultlessly rounding a raw time recorded by a stopwatch or electronic timing system to a submitted time.

Researchers now found certain stopwatches commit rounding errors when converting raw times to final submitted times. They outline a series of computer simulations based on procedures for converting raw race times for display.

These researchers were inspired when they encountered the issue firsthand while volunteering at a swim meet. While helping input times into the computer, they noticed a large portion of times they inputted were rounded to either the closest half-second or full second.

Later, when the frequencies of the digit pairs were plotted, a distinct pattern emerged. They discovered that the distribution of digit pairs was statistically inconsistent with the hypothesis that each digit pair was equally likely, as one would expect from stopwatches.

Stopwatches and electronic timing systems use quartz oscillators to measure time intervals, with each oscillation calculated as 0.0001 seconds. These times are then processed for display to 0.01 seconds, for example, to the public at a sporting venue.

When the researchers  processed raw times through the standard display routine, the uniform distribution disappeared. Most times were correctly displayed.

Where rounding errors occurred, they usually resulted in changes of one one-hundredth of a second. One raw time of 28.3194 was converted to a displayed time of 28.21.

The researchers collected more than 30,000 race times from swimming competitions and will investigate if anomalous timing patterns appear in the collection, which would suggest the potential for rounding errors in major sporting events.

David A. Faux et al, The floating point: Rounding error in timing devices, American Journal of Physics (2021). DOI: 10.1119/10.0003919

https://phys.org/news/2021-07-rounding-errors-stopwatches-wrong-win...