Comment

Comment by Dr. Krishna Kumari Challa on Tuesday

The study also found that different bird species have different impacts in terms of seed dispersal. Smaller birds disperse more seeds, but they can only spread small seeds from trees with lower carbon storage potential. In contrast, larger birds such as the Toco toucan or the Curl-crested jay disperse the seeds of trees with a higher carbon storage potential. The problem is that the larger birds are less likely to move across highly fragmented landscapes.
This crucial information enables us to pinpoint active restoration efforts—like tree planting—in landscapes falling below this forest cover threshold, where assisted restoration is most urgent and effective.
Allowing larger frugivores to move freely across forest landscapes is critical for healthy tropical forest recovery.
This study demonstrates that especially in tropical ecosystems seed dispersal mediated by birds, plays a fundamental role in determining the species that can regenerate.

Frugivores enhance potential carbon recovery in fragmented landscapes, Nature Climate Change (2024). DOI: 10.1038/s41558-024-01989-1

Comment by Dr. Krishna Kumari Challa on Tuesday

Tropical forests can't recover naturally without fruit eating birds, carbon recovery study shows

New research illustrates a critical barrier to natural regeneration of tropical forests. Their models—from ground-based data gathered in the Atlantic Forest of Brazil—show that when wild tropical birds move freely across forest landscapes, they can increase the carbon storage of regenerating tropical forests by up to 38%.

Fruit eating birds such as the Red-Legged Honeycreeper, Palm Tanager, or the Rufous-Bellied Thrush play a vital role in forest ecosystems by consuming, excreting, and spreading seeds as they move throughout a forested landscape.

Between 70% to 90% of the tree species in tropical forests are dependent on animal seed dispersal. This initial process is essential for allowing forests to grow and function. While earlier studies have established that birds are important for forest biodiversity, researchers now have a quantitative understanding of how they contribute to forest restoration. The new study, published in the journal Nature Climate Change provides evidence of the important contribution of wild birds (frugivores) in forest regeneration. Researchers compared the carbon storage potential that could be recovered in landscapes with limited fragmentation, with that of highly fragmented landscapes. Their data shows that highly fragmented landscapes restrict the movement of birds, thereby reducing the potential of carbon recovery by up to 38%.
Across the Atlantic Forest region in Brazil, the researchers found that it is critical to maintain a minimum of 40% forest cover. They also find that a distance of 133 meters (approximately 435 feet) or less between forested areas ensures that birds can continue to move throughout the landscape and facilitate ecological recovery.

Part 1

Comment by Dr. Krishna Kumari Challa on Monday

How did this unusual exception emerge? What distinguishes the enzyme from all others, causing it to form a fractal shape? Teaming up with structural biologist at the university of Marburg, the team eventually managed to determine the molecular structure of this assembly using electron microscopy, which illuminated how it achieves its fractal geometry.
It now became clear how exactly this protein manages to assemble into a fractal: Normally, when proteins self-assemble, the pattern is highly symmetrical: each individual protein chain adopts the same arrangement relative to its neighbors. Such symmetrical interactions always lead to patterns that become smooth on large scales.

The key to the fractal protein was that its assembly violated this rule of symmetry. Different protein chains made slightly different interactions at different positions in the fractal. This was the basis for forming the Sierpiński triangle, with its large internal voids, rather than a regular lattice of molecules.

Self-assembly is often used by evolution to regulate enzymes, but in this case the cyanobacterium that this enzyme is found in does not seem to care much whether or not its citrate synthase can assemble into a fractal.
When the team genetically manipulated the bacterium to prevent its citrate synthase from assembling into the fractal triangles, the cells grew just as well under a variety of conditions. This prompted them to wonder whether this might just be a harmless accident of evolution. Such accidents can happen when the structure in question isn't too difficult to construct.
To test their theory, the team recreated the evolutionary development of the fractal arrangement in the laboratory. To do this, they used a statistical method to back-calculate the protein sequence of the fractal protein as it was millions of years ago.

By then producing these ancient proteins biochemically they were able to show that the arrangement arose quite suddenly through a very small number of mutations and was then immediately lost again in several cyanobacterial lineages, so that it only remained intact in this single bacterial species.
The fact that something so complex-looking as a molecular fractal could emerge so easily in evolution suggests that more surprises and much beauty may still lie hidden in so far undiscovered molecular assemblies of many biomolecules.

Franziska L. Sendker et al, Emergence of fractal geometries in the evolution of a metabolic enzyme, Nature (2024). DOI: 10.1038/s41586-024-07287-2

Part 2

Comment by Dr. Krishna Kumari Challa on Monday

Discovery of the first fractal molecule in nature

An international team of researchers has stumbled upon the first regular molecular fractal in nature. They discovered a microbial enzyme—citrate synthase from a cyanobacterium—that spontaneously assembles into a pattern known as the Sierpinski triangle. Electron microscopy and evolutionary biochemistry studies indicate that this fractal may represent an evolutionary accident.

The study is published in Nature.

Snowflakes, fern leaves, romanesco cauliflower heads: many structures in nature have a certain regularity. Their individual parts resemble the shape of the whole structure. Such shapes, which repeat from the largest to the smallest, are called fractals. But regular fractals that match almost exactly across scales, as in the examples above, are very rare in nature.

Molecules also have a certain regularity. But if you look at them from a great distance, you can no longer see any signs of this. Then you see smooth matter whose features no longer match those of the individual molecules. The degree of fine structure we see depends on our magnification—in contrast to fractals, where self-similarity persists at all scales. In fact, regular fractals at the molecular level are completely unknown in nature till now.

This is somewhat surprising. After all, molecules can assemble themselves into all sorts of wonderful shapes. Scientists have extensive catalogues of self-assembled complex molecular structures. However, there has never been a regular fractal among them. It turns out that almost all regular-looking self-assemblies lead to the kind of regularity that becomes smooth on large scales.

Researchers now discovered a microbial enzyme—citrate synthase from a cyanobacterium—that spontaneously assembles into a regular fractal pattern known as the Sierpiński triangle. This is an infinitely repeating series of triangles made up of smaller triangles.

The protein makes these beautiful triangles and as the fractal grows, we see these larger and larger triangular voids in the middle of them, which is totally unlike any protein assembly we've ever seen before.

Part 1

Comment by Dr. Krishna Kumari Challa on Sunday

They studied plastic, paper and plant-based straws obtained in the USA. It showed that paper and plant-based straws contain PFAS (Per- and polyfluoroalkyl substances).

These are fluorine-based chemicals that have remarkable properties in repelling water, grease and pretty much anything. They are widely used in products designed to resist water and oil such as raincoats, furniture, cookware and food packaging.

PFAS are chemically and thermally very stable which means that almost nothing reacts or degrades them. This means they persist in the environment and will do so for thousands of years. For this reason, they have been dubbed ‘forever chemicals’.

They have been found literally everywhere from the Arctic ice to the Amazon rainforest. They also make it into the human body by migrating from packaging into our food and drink.

Once PFAS are in our blood they are associated with a number of health effects such as liver and kidney disease. There is also evidence that PFAS may lead to increased risk of high blood pressure in pregnant ..., and decreased immune response. Some studies show an association of PFAS exposure with kidney and testicular cancer. They have been shown to harm wildlife too.

All the evidence points to paper and plant-based straws having significant PFAS in them. PFAS have also been found in plastic straws but at lower levels. The only material determined to be free of PFAS was stainless steel.

Stainless steel straws  are reusable and easy to clean. So I use only them.

Please use only steel straws.

**

Comment by Dr. Krishna Kumari Challa on Sunday

Paper straws contain more potentially toxic ‘forever chemicals’ than plastic. Should you give them up?

Many paper straws tested by scientists contain significant amounts of chemicals that don't biodegrade.

If you have been following the scientific debate on the effect of different types of straw on the environment and human health, you’ll know that the decision whether to use a straw or not  is not an easy one.

Pictures of plastic straws causing the death of turtles and other aquatic life were published in national newspapers. Governments scrambled to justify they had let plastic pollution reach such an appalling state of affairs – they singled out plastic straws as something that they could ban. And so they did, ignoring those of us who warned about the unexpected consequences.

A study by a European research group showed there are significant health and environmental risks associated with the pape... that have replaced plastic straws.

Scientists observing the performance of the new paper straws found themselves puzzled by their ability to repel liquids and resist getting soggy. Could there be an additive, they wondered, that might be allowing paper straws to perform so well?

Part 1

Comment by Dr. Krishna Kumari Challa on April 13, 2024 at 1:48pm

The circadian rhythm is defined as physical, mental, and behavioral changes that organisms, such as humans, experience over 24-hour cycles. One of the most famous behaviors impacted by the circadian rhythm is sleep—people tend to feel sleepy at the same time every night. However, it has also been noted that the circadian rhythm can be impacted by the lunar cycle—people have been found to go to bed later and sleep less, for example, on nights before a full moon.

To learn more about the ovarian cycle-controlling mechanism, the research team obtained medical records for over 3,000 women living in Europe and North America, which held data relating to 27,000 ovarian cycles. The team tracked the first day of each cycle for all the women under study. In doing so, they found little correlation between cycle start time and lunar cycling.

The researchers did find something else, though. Many examples of what they describe as phase jumps—where something disturbs the timing of a cycle for a given woman, and the body responds by changing the clock rhythm over several months to bring the cycle back to its original norm. They compare it to how the circadian rhythm reacts to people experiencing jet lag. This, they suggest, indicates that the circadian rhythm is much more likely the mechanism that controls ovarian cycling.

 René Ecochard et al, Evidence that the woman's ovarian cycle is driven by an internal circamonthly timing system, Science Advances (2024). DOI: 10.1126/sciadv.adg9646

Part 2

Comment by Dr. Krishna Kumari Challa on April 13, 2024 at 1:46pm

Study of data from thousands of women suggests ovarian cycle is regulated by circadian rhythm

A team of reproductive researchers affiliated with several institutions in France and the U.S. has found that the timing of monthly ovarian cycles in women is mostly likely attributable to the circadian rhythm. In their paper published in the journal Science Advances, the group describes their study of thousands of ovarian cycles as reported by thousands of women in Europe and the U.S. and what they found.

The timing mechanism behind the ovarian cycle has mystified scientists for centuries, though one of the strongest theories has been that it is tied to the lunar cycle*. Charles Darwin suggested that the two became linked back when humans lived near the seashore, where the tides heavily impacted daily scheduling.

And three years ago a team led by Würzburg chronobiologist Charlotte Förster found evidence for women's menstrual cycles temporarily synchronizing with cycles of the moon.

In this new effort, the research team has found little evidence of a lunar impact—they suggest the mechanism most likely controlling the ovarian cycle is the circadian rhythm.

* C. Helfrich-Förster el al., "Women temporarily synchronize their menstrual cycles with the luminance and gravimetric cycles of the Moon," Science

advances (2021). advances.sciencemag.org/lookup … .1126/sciadv.abe1358

Part 1

Comment by Dr. Krishna Kumari Challa on April 13, 2024 at 1:40pm

Scientists uncover a missing link between poor diet and higher cancer risk

A research team has unearthed new findings that may help explain the connection between cancer risk and poor diet, as well as common diseases like diabetes, which arise from poor diet. The insights gained from this study hold promise for advancing cancer prevention strategies aimed at promoting healthy aging.

Cancer is caused by the interaction between our genes and factors in our environment, such as diet, exercise, and pollution. How such environmental factors increase cancer risk is not yet very clear, but it is vital to understand the connection if we are to take preventive measures that help us stay healthy longer.

A chemical linked to diabetes, obesity, and poor diet can heighten cancer risk

The research team first studied patients who are at a high risk of developing breast or ovarian cancers because they inherit a faulty copy of the cancer gene—BRCA2—from their parents. They demonstrated that cells from such patients were particularly sensitive to the effects of methylglyoxal, which is a chemical produced when our cells break down glucose to create energy.

The study showed that this chemical can cause faults in our DNA that are early warning signs of cancer development.

The team's research also suggested that people who do not inherit a faulty copy of BRCA2 but could experience higher-than-normal levels of methylglyoxal—such as patients with diabetes or pre-diabetes, which are connected with obesity or poor diet—can accumulate similar warning signs indicating a higher risk of developing cancer.

This research suggests that patients with high methylglyoxal levels may have higher cancer risk. Methylglyoxal can be easily detected by a blood test for HbA1C, which could potentially be used as a marker. Furthermore, high methylglyoxal levels can usually be controlled with medicines and a good diet, creating avenues for proactive measures against the initiation of cancer.

Interestingly, the research team's work also revised a longstanding theory about certain cancer-preventing genes. This theory—called the Knudson's 'two-hit' paradigm—was first formulated in 1971, and it was proposed that these genes must be inactivated permanently in our cells before cancer can arise.

The NUS team has now found that methylglyoxal can temporarily inactivate such cancer-preventing genes, suggesting that repeated episodes of poor diet or uncontrolled diabetes can 'add up' over time to increase cancer risk. This new knowledge is likely to be influential in changing the direction of future research in this area.

Li Ren Kong et al, A glycolytic metabolite bypasses "two-hit" tumor suppression by BRCA2, Cell (2024). DOI: 10.1016/j.cell.2024.03.006

Comment by Dr. Krishna Kumari Challa on April 13, 2024 at 12:17pm

Scientists wanted to know how this inflammatory process was damaging the brain. They Researchers were particularly interested in molecular aggregates, called cofilactin rods (CARs), that appear after a stroke. CARs form when two proteins, called cofilin and actin, that normally maintain neurites, break loose, forming messy clumps.

CARs are known to form in response to a chemical called superoxide, which immune cells release when the brain is inflamed.

To get a closer look at this process, the researchers stimulated inflammation in a part of the mouse brain that controls movement. They expected that neurons would die and the mice would have trouble moving.

The mice did struggle to move, but when the researchers looked at their brain tissue under a microscope, they were surprised to see that only the neurites had withered away, leaving the neurons isolated like stars in the night sky. The loss of these connections was enough to rob the mice of some of their motor coordination.

The scientists then tried reducing the amount of either superoxide or cofilin, and treated the brain with the same inflammatory substance. Under these conditions, fewer CARs formed, and the neurites survived. The mice also retained their coordination.

They had discovered a new pathway: inflammation caused immune cells to release superoxide, pulling cofilin and actin out of neurites and making CARs. Neurites died, and the disconnected brain malfunctioned.

Many neurological diseases involve inflammation, including multiple sclerosis, traumatic brain injury, and amyotrophic lateral sclerosis (ALS).

Now that scientists understand it better, they can design therapies to interrupt this inflammatory pathway. Stroke patients, for example, could be treated early on with anti-inflammatory agents to shield neurites from damage and preserve cognition.

Gökhan Uruk et al, Cofilactin rod formation mediates inflammation-induced neurite degeneration, Cell Reports (2024). DOI: 10.1016/j.celrep.2024.113914

Part 2

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