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Comment by Dr. Krishna Kumari Challa on June 27, 2024 at 11:35am

Lichen partnerships challenged by changes in climate

Lichen, which people may think of as a single organism, is in fact a community of several species that depend on each other for survival. Lichen symbiosis includes at least one fungus and one alga, along with other fungi and bacteria in roles that are still being investigated by biologists.

The continued health of lichens is vital to the future of our Northern forests because they provide a critical winter food source for many animals. They are also valuable "sentinels" of air quality and environmental health. For these reasons, scientists are eager to understand how they may be affected by climate change.

New research published in Science Advances from the University of Minnesota investigated symbiosis in boreal oak lichen, a variety widespread on several tree species across Minnesota and the Northwoods.

Using multiple research methods, the team found:

• The partner organisms that make up lichen symbioses are not always in sync—one organism may have an extreme response to changes in moisture while its partner remains unaffected.
• These differences may drive one partner to "go it alone" under some conditions, disrupting the symbiosis—other research has observed this in corals.
• The team used gas exchange data to show asymmetries in carbon balance are widespread across evolutionarily disparate lichen groups.

Part 1

Comment by Dr. Krishna Kumari Challa on June 27, 2024 at 11:25am

Scientists determine that connexin molecules allow cells to send messages to each other

Researchers have gained new knowledge of how drugs bind to connexin molecules. These molecules form channels that allow neighboring cells to send direct messages to one another. Dysfunctions of these channels are involved in neurological and cardiac diseases. The new understanding of how drugs bind and act on them should help develop therapies to treat such conditions.

Adjacent cells can communicate directly through relatively large channels called gap junctions, which allow cells to freely exchange small molecules and ions with each other or with the outside environment. In this way, they can coordinate activities in the tissues or organs that they compose and maintain homeostasis.

Such channels are created from proteins known as connexins. Six connexins situated in the cell membrane create a hemichannel; this hemichannel joins with a hemichannel in a neighboring cell to create a two-way channel.

When connexin channels do not work properly, they cause changes in intercellular communication that have been linked to many different diseases. These include cardiac arrhythmias, diseases of the central nervous system such as epilepsy, neurodegenerative diseases and cancer.

As a result, the search is on for drugs that target connexins.

So understanding of the structure of connexins and how drugs bind to connexin channels to block or activate them is vital for treatment of these diseases. Indeed, of the 21 types of connexins known to exist in humans, few of them are currently evaluated as drug targets.

Find more information here:  Xinyue Ding et al, Structural basis of connexin-36 gap junction channel inhibition, Cell Discovery (2024). DOI: 10.1038/s41421-024-00691-y

Comment by Dr. Krishna Kumari Challa on June 27, 2024 at 11:15am

Researchers discover how mitochondrial transfer restores heart muscle

Transferring mitochondria from a patient's healthy skeletal muscle to damaged, ischemic heart tissue has been shown to restore heart muscle, increase energy production, and improve ventricular function.

 Researchers realized the probability of recovery was much higher if they added mitochondria.

To date, 16 children have undergone autologous mitochondria transplantation. Of these, 80% were able to come off ECMO, compared with a historical rate of 40%.

But mitochondrial transfer has faced skepticism—in part because no one really knew why it works.

The researchers earlier thought that  it was mitochondria going into cells and taking over and generating all of the cell's power. But what didn't make sense was that they only needed very small amounts of mitochondria for the heart muscle to recover. The math didn't add up.

A new study published in the journal Nature, found a surprising explanation. The transferred mitochondria trigger the cell to destroy its low-performing mitochondria through autophagy—a kind of cellular housekeeping.

This gives cells a better pool of mitochondria, improving their bioenergetics and fitness. This insight could ultimately improve care for broad range of heart conditions.

The research team is now investigating whether mitochondrial transfer could improve the success of cardiac transplantation when the heart is donated after circulatory death (DCD). DCD hearts could potentially expand the donor pool, but have ischemic damage and thus are difficult to transplant. The researchers think treatment with mitochondria will help with their recovery.

Ruei-Zeng Lin et al, Mitochondrial transfer mediates endothelial cell engraftment through mitophagy, Nature (2024). DOI: 10.1038/s41586-024-07340-0

Comment by Dr. Krishna Kumari Challa on June 27, 2024 at 11:05am

Scientists discover genetic 'off switch' in legume plants that limits biological ability to source nutrients

A genetic "off switch" that shuts down the process in which legume plants convert atmospheric nitrogen into nutrients has been identified for the first time by a team of international scientists.

Legumes like beans, peas and lentils are unique among crops for their ability to interact with soil bacteria to convert or "fix" nitrogen into a usable form of nutrients. However, this energy-intensive biological process is reduced when nitrogen is already abundant in the soil either through natural processes or through the application of synthetic fertilizer.

The latest discovery of the genetic regulator that turns off nitrogen fixation when soil nitrate levels are high allowed scientists to remove the gene in model legumes, ensuring they continued to fix nitrogen regardless of the soil environment.

Increasing the biological ability of legumes to fix nitrogen could help increase crop growth and yield while also reducing the need for synthetic fertilizers, which contribute to agriculture's environmental footprint.

Dugald Reid, Zinc mediates control of nitrogen fixation via transcription factor filamentation, Nature (2024). DOI: 10.1038/s41586-024-07607-6. www.nature.com/articles/s41586-024-07607-6

Comment by Dr. Krishna Kumari Challa on June 27, 2024 at 10:59am

Within organisms, the attachment of carbohydrates, or "glycans," onto proteins or lipids—a process called "glycosylation"—plays an essential role in a staggering number of physiological processes. It is necessary for cell recognition, cell signaling, immune response, protein folding, development and fertilization. Meanwhile, the slightest alteration in the structure of glycans can lead to or aggravate diseases from cancer and diabetes to Alzheimer's and muscular dystrophy.

Glycans and their associated processes are in fact so important that they get their own field: glycobiology. And within this discipline, almost all of the enzymes—the molecules that kick off or speed up chemical reactions—that are responsible for production of glycans in humans have been identified and categorized, as well as the various production processes, or "biosynthetic pathways."

Studying these mechanisms in detail is vital for disease process identification and controlling it.

Full details about the work can be found here: 

 Yuko Tokoro et al, LacdiNAc synthase B4GALNT3 has a unique PA14 domain and suppresses N-glycan capping, Journal of Biological Chemistry (2024). DOI: 10.1016/j.jbc.2024.107450

Part 2

Comment by Dr. Krishna Kumari Challa on June 27, 2024 at 10:56am

Biologists uncover how key carbohydrate-attachment mechanism malfunctions and causes various diseases

Researchers have uncovered how a structure in bodily carbohydrates (sugar chains or "glycans") that regulates how they attach themselves to other molecules interacts with key enzymes, and in so doing can contribute to a range of diseases.

One of the most essential bodily biochemical processes involves carbohydrates (sugar chains or "glycans") attaching themselves to proteins and fats (lipids), and when this process malfunctions, the risk of contracting a raft of diseases sharply increases. Researchers have recently discovered how a crucial enzyme's interaction with a small structure in glycans during this attachment can contribute to such breakdowns.

Their findings are described in a paper published online in the Journal of Biological Chemistry on June 4, 2024.

Part 1

Comment by Dr. Krishna Kumari Challa on June 27, 2024 at 10:19am

While hunting for zebrafish with different gap junction mutations, the researchers made an intriguing find: a zebrafish that couldn't move its tail properly. Usually, a zebrafish embryo will flop around and spontaneously flick its tail, but these fish didn't do that.
In healthy zebrafish, researchers can watch the electrical signals propagate through the gap junctions between muscle cells, like a plume of food dye diffusing into a cup of water. In fish with this mutation, the signals don't flow. The mutation was impairing electrical communication between the cells via the gap junctions.

And that communication breakdown led to improper muscular development, the team showed. In an ordinary healthy zebrafish, the muscle fibers are straight and orderly. In this zebrafish with this mutation, the muscle fibers are crinkly and wavy, like crepe paper streamers.

The researchers pinned the change on a mutation in a specific gene. Through a series of experiments, they showed that this gene, when functioning normally, makes the gap junction channels between muscle cells that allow the nervous system to coordinate the activity of early developing muscle. And without appropriate electrical signaling at the right time during development, the muscle fibers can't organize properly, causing crinkly muscle fibers and severe muscle defects.
So scientists figured out that this gap junction channel is a conduit—it allows electricity from the nerve cells to be sent out to muscle fibers.
More than a curiosity, though, the findings can help inform scientists' understanding of muscle development in humans. In disorders where muscles don't develop properly, faulty gap junction channels might be one cause, a link that was previously unknown.
The transfer of bioelectricity from one organ system to another is critical for development and adult function. Finding the genes that allow this to occur, understanding how they work, and exactly what goes wrong when communication is disrupted, will provide new insight into human disease.

Gap-junction-mediated bioelectric signaling required for slow muscle development and function in zebrafish, Current Biology (2024). DOI: 10.1016/j.cub.2024.06.007. www.cell.com/current-biology/f … 0960-9822(24)00759-0

Part 2

Comment by Dr. Krishna Kumari Challa on June 27, 2024 at 10:16am

How bioelectricity shapes muscle development

A new research work describes how nerve cells and muscle cells communicate through electrical signals during development—a phenomenon known as bioelectricity.

The communication, which takes place via specialized channels between cells, is vital for proper development and behavior. The study identifies specific genes that control the process, and pins down what happens when it goes wrong.

The finding offers clues to the genetic origins of muscle disorders in humans, and taps into longstanding questions in developmental biology.

Model organisms like mice, fruit flies and worms allow scientists to do experiments that aren't possible in humans, answering fundamental biological questions and providing guidance for more focused testing in humans.

Zebrafish were a promising addition to the scene. Zebrafish and humans share many genes, making the fish useful for testing the genetic underpinnings of human diseases and conditions. And because zebra fish embryos are transparent, scientists can watch development happen in real time under the microscope.

Zebrafish are the perfect species to study electrical communication. Thanks to their transparent embryos,  researchers can image electricity flowing through cells in real time.

Part 1

Comment by Dr. Krishna Kumari Challa on June 27, 2024 at 10:06am

Inactivity rates varied widely between countries. For example, 66 percent of adults do not get enough physical activity in the United Arab Emirates, while the figure was under three percent in Malawi.

There was also a gender gap. Nearly 34 percent of women worldwide do not reach the activity threshold, compared to 29 percent of men.

There are "multiple causes" for activity rates declining overall, including that people are walking less, working at computers more and generally spending more leisure time looking at screens, Bull said.

Don't just sit on (your) chairs, get up and be active—every step counts!

 Tessa Strain et al, National, regional, and global trends in insufficient physical activity among adults from 2000 to 2022: a pooled analysis of 507 population-based surveys with 5·7 million participants, The Lancet Global Health (2024). DOI: 10.1016/S2214-109X(24)00150-5

Part 2

Comment by Dr. Krishna Kumari Challa on June 27, 2024 at 10:05am

'Wake-up call': third of adults not doing enough physical activity

Nearly a third of all adults are not doing enough physical activity, posing a growing threat to health across the world, a major study said this week.

More than 31 percent of adults—1.8 billion people—did not get the recommended amount of physical exercise in 2022, an increase of five percentage points from 2010, according to a study by the World Health Organization and other researchers.

"Physical inactivity is a silent threat to global health, contributing significantly to the burden of chronic diseases," said Ruediger Krech, director of the WHO's health promotion department.

"Unfortunately the world is not going in the right direction," he told an online press conference.

To be healthy, the WHO recommends all adults spend at least 150 minutes every week doing moderate-intensity physical activity—which can include walking, cycling or even heavy household chores—or at least 75 minutes of more vigorous exercise, such as running or competing in sport.

A combination of the two will also get people over the line.

A combination of the two will also get people over the line. Not getting this level of exercise increases the risk of people developing heart disease, diabetes, some cancers as well as mental health problems, Krech said.

If current trends continue, adult inactivity levels are projected to rise to 35 percent by 2030, according to the study in The Lancet Global Health.

This would fall far short of the WHO's goal of reducing physical inactivity by 15 percent by the end of the decade.

Fiona Bull, head of the WHO's physical activity unit, said the research was "a wake-up call that we're not doing enough".

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