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Comment by Dr. Krishna Kumari Challa on February 28, 2023 at 8:41am

Tissue engineering: Developing bioinspired multi-functional tendon-mimetic hydrogels

Materials scientists work to develop advanced biological materials for medical devices and tissue engineering platforms to emulate natural biological tissue architectures via materials engineering. However, the natural tissue architecture has a variety of characteristics that are difficult to synthetically replicate. The architecture of tendons relies on the load-bearing capacities of the musculoskeletal system to provide biophysical cues that translate into cellular behaviors via interfacial interactions. In the past decade, researchers had devoted extensive research efforts to engineer tendon-mimetic materials with high structural anisotropy.

In a new report now published in Science Advances,  a research team in physics, mechanical engineering, electrical and electronic engineering reported the development of multifunctional tendon-mimetic hydrogels by assembling aramid nanofiber composites. 

The anisotropic composite hydrogels (ACH) contained stiff nanofibers and soft polyvinyl alcohol moieties to mimic biological interactions that typically occur between collagen fibers and proteoglycans  in tendons. The team was bioinspired by natural tendons to develop hydrogels with a high elastic modulus, strength and fracture toughness.

The researchers biofunctionalized these material surfaces with bioactive molecules to present biophysical cues to impart behavioral similarities to those of cell attachment. Additionally, the soft bioelectronic components integrated on the hydrogels facilitated a variety of physiological benefits. Based on the outstanding functionality of the tendon-mimetics, the team envisioned broader applications of the materials in advanced tissue engineering to form implantable prosthetics for human-machine interactions.

Mingze Sun et al, Multifunctional tendon-mimetic hydrogels, Science Advances (2023). DOI: 10.1126/sciadv.ade6973

Jeong-Yun Sun et al, Highly stretchable and tough hydrogels, Nature (2012). DOI: 10.1038/nature11409

Comment by Dr. Krishna Kumari Challa on February 26, 2023 at 10:13am

Even to this day, however, it's still unclear how so many animals achieve these incredible feats of navigation.

In the 1970s, scientists suggested that this magnetic-compass sense could involve radical pairs, molecules with unpaired outer shell electrons that form a pair of entangled electrons whose spins are altered by the Earth's magnetic field.

Twenty-two years later, that study's lead author co-authored a new paper proposing a specific molecule in which the radical pairs could be formed.

This molecule – a receptor in the retina of migrating birds called a cryptochrome – can sense light and magnetism, and it seems to work through quantum entanglement.

In basic terms, when a cryptochrome absorbs light, the energy triggers one of its electrons, pushing it to occupy one of two spinning states, each of which is differently influenced by Earth's geomagnetic field.

Cryptochromes have been a leading explanation for how animals sense magnetic fields for two decades, but now researchers at the Universities of Manchester and Leicester have identified another candidate.

Manipulating the genes of fruit flies, the team found that a molecule called Flavin Adenine Dinucleotide (FAD), which usually forms a radical pair with cryptochromes, is actually a magnetoreceptor in and of itself.

This basic molecule is found at differing levels in all cells, and the higher the concentration, the more likely it is to impart magnetic sensitivity, even when cryptochromes are lacking.

In fruit flies, for instance, when FAD is stimulated by light, it generates a radical pair of electrons that are responsive to magnetic fields.

However, when cryptochromes are present alongside FADs, a cell's sensitivity to magnetic fields increases. The findings suggest that cryptochromes are not as essential as we thought for magnetoreception.

That shows cells can, at least in a laboratory, sense magnetic fields through other ways."

The discovery could help explain why human cells show sensitivity to magnetic fields in the lab. The form of cryptochrome present in the cells of our species' retina has proved capable of magnetoreception at a molecular level when expressed in fruit flies.

However, this doesn't mean humans utilize that function, nor is there evidence that cryptochrome guides our cells to line up along magnetic fields in the lab.

Even though human cells show sensitivity to Earth's magnetic field, we don't have a conscious sense of that force. Maybe that's because we don't have any cryptochromes assisting.

This study may ultimately allow us to better appreciate the effects that magnetic field exposure might potentially have on humans.

https://www.nature.com/articles/s41586-023-05735-z

Part 2

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Comment by Dr. Krishna Kumari Challa on February 26, 2023 at 10:10am

All Living Cells Could Have The Molecular Machinery For a 'Sixth Sense'

Every animal on Earth may house the molecular machinery to sense magnetic fields, even those organisms that don't navigate or migrate using this mysterious 'sixth sense'.

Scientists working on fruit flies have now identified a ubiquitous molecule in all living cells that can respond to magnetic sensitivity if it is present in high enough amounts or if other molecules assist it.

The new findings suggest that magnetoreception could be much more common in the animal kingdom than we ever knew. If researchers are right, it might be an astonishingly ancient trait shared by virtually all living things, albeit with differing strengths.

That doesn't mean all animals or plants can actively sense and follow magnetic fields, but it does suggest that all living cells might, including ours.

How we sense the external world, from vision, hearing through to touch, taste, and smell, are well understood.

But by contrast, which animals can sense and how they respond to a magnetic field remains unknown. This study has made significant advances in understanding how animals sense and respond to external magnetic fields - a very active and disputed field.

Magnetoreception might sound like magic to us, but plenty of fish, amphibians, reptiles, birds, and other mammals in the wild can sense the tug of Earth's magnetic field and use it to navigate space.

Because this force is essentially invisible to our species, it took a remarkably long time for scientists to notice it.

Only in the 1960s did scientists show that bacteria can sense magnetic fields and orient themselves in relation to those fields; in the 1970s, we found that some birds and fish follow Earth's magnetic field when migrating.

Part 1

Comment by Dr. Krishna Kumari Challa on February 26, 2023 at 8:18am

Combining forces to advance ocean science

Comment by Dr. Krishna Kumari Challa on February 25, 2023 at 12:59pm

How scientists hauling logs on their heads may have solved a Chaco Canyon mystery!

Why did researchers carry a log weighing more than 130 pounds for 15 miles? Their feat of endurance could reveal new information about how ancient peoples hauled more than 200,000 heavy timbers to a site in the modern-day Southwest called Chaco Canyon.

In a new study, several researchers reenacted a small part of a trek that people in the Southwest United States may have made more than 1,000 years ago.

They described their experiment Feb. 22 in the Journal of Archaeological Science: Reports.

This is also done by sherpas in Nepal.

The researchers  they were hoping to solve an archaeological mystery that has perplexed researchers for decades: How did ancient peoples transport more than 200,000 heavy construction timbers over 60 miles to a famous site in the Southwest called Chaco Canyon?

The team's findings show that the key to this testament to human labor may have been simple devices called tumplines. These straps, which sherpas, or native mountain peoples of Nepal, still widely use today, loop over the top of the head. They help porters to support weight using the bones of their neck and spine rather than their muscles. Archaeological evidence suggests that ancient peoples in the Southwest employed tumplines woven from yucca plants to transport everyday items like food and water.

Tumplines allow one to carry heavier weights over larger distances without getting fatigued.

Chaco Canyon sits near the border between New Mexico and Colorado. Thousands of people, the ancestors of today's Diné, or Navajo, and Pueblo peoples, may have lived there from around A.D. 850 to 1200. They built "Great Houses," which were as much as four stories tall and contained hundreds of rooms.

But how this society got its construction supplies has been a long-standing mystery. Human porters would have needed to carry 16-foot-long wooden beams to Chaco Canyon by foot—following a network of ancient roads to sites like the Chuska Mountains to the west.

The team's findings open up a new understanding of the day-to-day lives of the people who shaped the Southwest more than a thousand years ago.

the team's results show that supplying Chaco Canyon with goods may not have been as back-breaking an undertaking as archaeologists once assumed.

As these guys showed, you don't have to be super trained to carry a log.

ames A. Wilson et al, Were timbers transported to Chaco using tumplines? A feasibility study, Journal of Archaeological Science: Reports (2023). DOI: 10.1016/j.jasrep.2023.103876

Comment by Dr. Krishna Kumari Challa on February 25, 2023 at 12:19pm

How birds got their wings

Modern birds capable of flight all have a specialized wing structure called the propatagium without which they could not fly. The evolutionary origin of this structure has remained a mystery, but new research suggests it evolved in nonavian dinosaurs. The finding comes from statistical analyses of arm joints preserved in fossils and helps fill some gaps in knowledge about the origin of bird flight.

Comment by Dr. Krishna Kumari Challa on February 25, 2023 at 11:17am

Young adult mice with brain injury were injected with a substance which permanently labeled astrocytes in red and knocked out the function of a gene called p53—known to have a vital role in suppressing many different cancers. A control group was treated the same way, but the p53 gene was left intact. A second group of mice was subjected to p53 inactivation in the absence of injury.

Normally astrocytes are highly branched—they take their name from stars—but what we found was that without p53 and only after an injury the astrocytes had retracted their branches and become more rounded. They weren't quite stem cell-like, but something had changed. So scientists let the mice age, then looked at the cells again and saw that they had completely reverted to a stem-like state with markers of early glioma cells that could divide.

This suggested that mutations in certain genes synergized with brain inflammation, which is induced by acute injury and then increases over time during the natural process of aging to make astrocytes more likely to initiate a cancer. Indeed, this process of change to stem-cell like behavior accelerated when they injected mice with a solution known to cause inflammation.

The team then looked for evidence to support their hypothesis in human populations. They consulted electronic medical records of more than 20,000 people who had been diagnosed with head injuries, comparing the rate of brain cancer with a control group, matched for age, sex and socioeconomic status.

They found that patients who experienced a head injury were nearly four times more likely to develop a brain cancer later in life, than those who had no head injury. It is important to keep in mind that the risk of developing a brain cancer is overall low, estimated at less than 1% over a lifetime, so even after an injury the risk remains modest.

We know that normal tissues carry many mutations which seem to just sit there and not have any major effects. These new  findings suggest that if on top of those mutations, an injury occurs, it creates a synergistic effect.

In a young brain, basal inflammation is low so the mutations seem to be kept in check even after a serious brain injury. However, upon aging, the mouse work suggests that inflammation increases throughout the brain but more intensely at the site of the earlier injury. This may reach a certain threshold after which the mutation now begins to manifest itself.

Simona Parrinello, Injury primes mutation bearing astrocytes for dedifferentiation in later life, Current Biology (2023). DOI: 10.1016/j.cub.2023.02.013. www.cell.com/current-biology/f … 0960-9822(23)00152-5

Part 2

Comment by Dr. Krishna Kumari Challa on February 25, 2023 at 11:12am

Head injuries could be a risk factor for developing brain cancer

Cancer Researchers have provided important molecular understanding of how injury may contribute to the development of a relatively rare but often aggressive form of brain tumor called a glioma.

Previous studies have suggested a possible link between head injury and increased rates of brain tumors, but the evidence is inconclusive. The present work now identified a possible mechanism to explain this link, implicating genetic mutations acting in concert with brain tissue inflammation to change the behaviour of cells, making them more likely to become cancerous. Although this study was largely carried out in mice, it suggests that it would be important to explore the relevance of these findings to human gliomas.

Gliomas are brain tumors that often arise in neural stem cells. More mature types of brain cells, such as astrocytes, have been considered less likely to give rise to tumors. However, recent findings have demonstrated that after injury astrocytes can exhibit stem cell behavior again.

Researchers  therefore set out to investigate whether this property may make astrocytes able to form a tumour following brain trauma using a pre-clinical mouse model.

Part 1

Comment by Dr. Krishna Kumari Challa on February 25, 2023 at 11:05am

Scientists unlock key to drought-resistant wheat plants with longer roots

Growing wheat in drought conditions may be easier in the future, thanks to new genetic research.

An international team of scientists found that the right number of copies of a specific group of genes can stimulate longer root growth, enabling wheat plants to pull water from deeper supplies. The resulting plants have more biomass and produce higher grain yield, according to a paper published in the journal Nature Communications.

The research provides novel tools to modify wheat root architecture to withstand low water conditions.

Roots play a very important role in plants. The root absorbs the water and the nutrients to support plants' growth. This finding is a useful tool to engineer root systems to improve yield under drought conditions in wheat. 

Much has been done to improve wheat production but losses from water stress can erase other improvements. Plants that can adapt to low water conditions but have increased yield will be key to growing enough food for a growing population in the face of global warming.

Until now, little has been known about the genes that affect the root structure of wheat. The discovery of the gene family—known as OPRIII—and that different copies of these genes affect root length is a significant step.

The duplication of the OPRIII genes results in increased production of a plant hormone called Jasmonic acid that causes, among other processes, the accelerated production of lateral roots. Different dosages of these genes can be used to obtain different roots.

To get longer roots, the team of researchers used CRISPR gene editing technology to eliminate some of the OPRIII genes that were duplicated in wheat lines with shorter roots. By contrast, increasing the copies of these genes caused shorter and more branched roots. But inserting a rye chromosome, which result in decreased OPRIII wheat genes, caused longer roots.

Fine-tuning the dosage of the OPRIII genes can allow us to engineer root systems that are adapted to drought, to normal conditions, to different scenarios.

Knowing the right combination of genes means researchers can search for wheat varieties that have those natural variations and breed for release to growers planting in low-water environments.

Gilad Gabay et al, Dosage differences in 12-OXOPHYTODIENOATE REDUCTASE genes modulate wheat root growth, Nature Communications (2023). DOI: 10.1038/s41467-023-36248-y

Comment by Dr. Krishna Kumari Challa on February 25, 2023 at 10:49am

Human height remained unchanged for 2,000 years in Milan, finds study

A study covering 2,000 years of male and female adult statures in Milan, Italy, has been published in the journal Scientific Reports, illustrating a stable environmental influence on height.

Human height depends on an interplay between genetics and environmental factors like fetal health, childhood nutrition, disease exposures, as well as environmental epigenetic factors that can reach back generations. While genetics alone may determine how tall a person could become, the environment they are born into plays a significant role in how much of that genetic growth potential is realized. Typically when we look around the world, we see that as health and nutrition have become more reliable since the industrial revolution, humans have reached increasingly greater heights.

In past studies, population stature has been linked to environmental factors. Human height dramatically reduced during the switch from hunter-gatherers to more agricultural societies. Human height has been slowly increasing since then, occasionally being shown to wax and wane with times of sustained prosperity, wars, famines, climate change, and exposure to plague.

In the study, researchers analysed 549 skeletal remains from 13 different sites, all within Milan. The remains all came from necropolises dedicated to the less wealthy classes of Milanese society. They were assigned to one of five historical periods: Roman Era (first–fifth centuries AD), Early Middle Ages (sixth–tenth centuries AD), Late Middle Ages (eleventh–fifteenth centuries AD), Modern Era (sixteenth–eighteenth centuries AD) and Contemporary Era (nineteenth–twentieth centuries AD).

About 100 individuals were assessed for each era, split between male and female. Stature was estimated, mostly using femur bones, according to a well-established forensic regression formula. Individual female heights ranged from 143.5 to 177.6 cm, with a mean of 157.8 cm (about 5'2''). Males ranged from 152.0 to 195.4 cm, with a mean of 168.5 cm (5'6''). There was no significant change in average heights when comparing the historical periods.

By focusing their study on a single geographic location with similar urban and socioeconomic characteristics, researchers were able to remove biases that might arise in studies of multiple populations with distinct environmental influences. With such a homogenous environment, external forces on population height, like wars, plagues, or climate, should have been obvious. Surprisingly, there were no significant fluctuations seen in the statures. Suggesting to the study authors that city life in Milan has provided a stable environment for thousands of years, even for its lowest-income inhabitants.

 Lucie Biehler-Gomez et al, The diachronic trend of female and male stature in Milan over 2000 years, Scientific Reports (2023). DOI: 10.1038/s41598-023-28406-5

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