Comment

Comment by Dr. Krishna Kumari Challa on November 24, 2021 at 9:54am

When bees get a taste for dead things: Meat-eating 'vulture bees'

A little-known species of tropical bee has evolved an extra tooth for biting flesh and a gut that more closely resembles that of vultures rather than other bees.

Bees don't eat meat. However, a species of stingless bee in the tropics has evolved the ability to do so, presumably due to intense competition for nectar.

These are the only bees in the world that have evolved to use food sources not produced by plants, which is a pretty remarkable change in dietary habits.

Honeybees, bumblebees, and stingless bees have guts that are colonized by the same five core microbes. Unlike humans, whose guts change with every meal, most bee species have retained these same bacteria over roughly 80 million years of evolution. Given their radical change in food choice, a team of UCR scientists wondered whether the vulture bees'  gut bacteria differed from those of a typical vegetarian bee. They differed quite dramatically, according to a study the team published today in the American Society of Microbiologists' journal mBio.

To track these changes, the researchers went to Costa Rica, where these bees are known to reside. They set up baits—fresh pieces of raw chicken suspended from branches and smeared with petroleum jelly to deter ants.

The baits successfully attracted vulture bees and related species that opportunistically feed on meat for their protein. Normally, stingless bees have baskets on their hind legs for collecting pollen. However, the team observed carrion-feeding bees using those same structures to collect the bait.

For comparison, the team also collected stingless bees that feed both on meat and flowers, and some that feed only on pollen. On analyzing the microbiomes of all three bee types, they found the most extreme changes among exclusive meat-feeders.

The vulture bee microbiome is enriched in acid-loving bacteria, which are novel bacteria that their relatives don't have. These bacteria are similar to ones found in actual vultures, as well as hyenas and other carrion-feeders, presumably to help protect them from pathogens that show up on carrion.

Laura L. Figueroa et al, Why Did the Bee Eat the Chicken? Symbiont Gain, Loss, and Retention in the Vulture Bee Microbiome, mBio (2021). DOI: 10.1128/mBio.02317-21

https://phys.org/news/2021-11-bees-dead-meat-eating-vulture-sport.h...

Comment by Dr. Krishna Kumari Challa on November 23, 2021 at 12:12pm

COVIDisAirborne: Multiscale ComputationalMicroscopy of Delta SARS-CoV-2 in a Respiratory Aerosol

Comment by Dr. Krishna Kumari Challa on November 23, 2021 at 12:02pm

Crazy plan  to give Mars an artificial magnetosphere

Terraforming Mars is one of the great dreams of humanity. Mars has a lot going for it. Its day is about the same length as Earth's, it has plenty of frozen water just under its surface, and it likely could be given a reasonably breathable atmosphere in time. But one of the things it lacks is a strong magnetic field. So if we want to make Mars a second Earth, we'll have to give it an artificial one.

The reason magnetic fields are so important is that they shield a planet from solar wind and ionizing particles. Earth's magnetic field prevents most high-energy charged particles from reaching the surface. Instead, they are deflected from Earth, keeping us safe. The magnetic field also prevents solar winds from stripping Earth's atmosphere over time. Early Mars had a thick, water-rich atmosphere, but it was gradually depleted without the protection of a strong magnetic field.

Unfortunately, we can't just recreate Earth's magnetic field on Mars. Our field is generated by a dynamo effect in Earth's core, where the convection of iron alloys generates Earth's geomagnetic field. The interior of Mars is smaller and cooler, and we can't simply "start it up" to create a magnetic dynamo. But there are a few ways we can create an artificial magnetic field, as a recent study shows.

As the study points out, if you want a good planetary magnetic field, what you really need is a strong flow of charged particles, either within the planet or around the planet. Since the former isn't a great option for Mars, the team looks at the latter. It turns out you can create a ring of charged particles around Mars, thanks to its moon Phobos.

Phobos is the larger of the two Martian moons, and it orbits the planet quite closely—so closely that it makes a trip around Mars every eight hours. So the team proposes using Phobos by ionizing particles from its surface, then accelerating them so they create a plasma torus along the orbit of Phobos. This would create a magnetic field strong enough to protect a terraformed Mars.

It's a bold plan, and while it seems achievable, the engineering hurdles would be significant. But as the authors point out, this is the time for ideas. Start thinking about the problems we need to solve, and how we can solve them, so when humanity does reach Mars, we will be ready to put the best ideas to the test.

R.A. Bamford et al, How to create an artificial magnetosphere for Mars, Acta Astronautica (2021). DOI: 10.1016/j.actaastro.2021.09.023

https://phys.org/news/2021-11-absolutely-bonkers-mars-artificial-ma...

Comment by Dr. Krishna Kumari Challa on November 23, 2021 at 11:54am

 How longer lives are tied to physical activity: evolutionary explanation for why lack of physical activity as humans age increases disease risk and reduces longevity.

You know exercise is good for you. Some people can even rattle off reasons it keeps your muscles and joints strong, and how it fights off certain diseases. But  can  you tell the story of why and how physical activity was built into human biology?

A team of evolutionary biologists and biomedical researchers from Harvard are taking a run at it (sometimes literally) in a new study published in PNAS. The work lays out evolutionary and biomedical evidence showing that humans, who evolved to live many decades after they stopped reproducing, also evolved to be relatively active in their later years.

The researchers say that physical activity later in life shifts energy away from processes that can compromise health and toward mechanisms in the body that extend it. They hypothesize that humans evolved to remain physically active as they age—and in doing so to allocate energy to physiological processes that slow the body's gradual deterioration over the years. This guards against chronic illnesses such as cardiovascular disease, type 2 diabetes, and even some cancers.

Researchers examined two pathways by which lifelong physical activity reallocates energy to improve health. The first involves dealing excess energy away from potentially harmful mechanisms, like excess fat storage. The team also identified how physical activity allocates energy to repair and maintenance processes. The paper shows that besides burning calories, physical activity is physiologically stressful, causing damage to the body at the molecular, cellular, and tissue levels. The body's response to this damage, however, is essentially to build back stronger.

This includes repairing tears in muscle fibers, repairing cartilage damage, and healing microfractures. The response also causes the release of exercise-related antioxidants and anti-inflammatories, and enhances blood flow. In the absence of physical activity, these responses are activated less. The cellular and DNA repair processes have been shown to lower the risk of diabetes, obesity, cancer, osteoporosis, Alzheimer's, and depression.

The key take-home point is that because we evolved to be active throughout our lives, our bodies need physical activity to age well. In the past, daily physical activity was necessary in order to survive, but today we have to choose to exercise, that is do voluntary physical activity for the sake of health and fitness.

The active grandparent hypothesis: Physical activity and the evolution of extended human healthspans and lifespans, PNAS (2021). DOI: 10.1073/pnas.2107621118

https://phys.org/news/2021-11-outlines-longer-tied-physical.html?ut...

Comment by Dr. Krishna Kumari Challa on November 23, 2021 at 11:45am

How sugar-loving microbes could help power future cars

It sounds like modern-day alchemy: Transforming sugar into hydrocarbons found in gasoline.

But that's exactly what scientists have done.

In a forthcoming study in Nature Chemistry, researchers report harnessing the wonders of biology and chemistry to turn glucose (a type of sugar) into olefins (a type of hydrocarbon, and one of several types of molecules that make up gasoline).

Olefins comprise a small percentage of the molecules in gasoline as it's currently produced, but the process the team developed could likely be adjusted in the future to generate other types of hydrocarbons as well, including some of the other components of gasoline. Olefins have non-fuel applications, as they are used in industrial lubricants and as precursors for making plastics.

To complete the study, the researchers began by feeding glucose to strains of E. coli that don't pose a danger to human health. These microbes are sugar junkies. 

The E. coli in the experiments were genetically engineered to produce a suite of four enzymes that convert glucose into compounds called 3-hydroxy fatty acids. As the bacteria consumed the glucose, they also started to make the fatty acids.

To complete the transformation, the team used a catalyst called niobium pentoxide (Nb2O5) to chop off unwanted parts of the fatty acids in a chemical process, generating the final product: the olefins.

The scientists identified the enzymes and catalyst through trial and error, testing different molecules with properties that lent themselves to the tasks at hand. Using this method, they were able to make olefins directly from glucose.

Zhen Wang, A dual cellular–heterogeneous catalyst strategy for the production of olefins from glucose, Nature Chemistry (2021). DOI: 10.1038/s41557-021-00820-0. www.nature.com/articles/s41557-021-00820-0

---

Scientists are also interested in increasing the yield. Currently, it takes 100 glucose molecules to produce about 8 olefin molecules, Wang says. She would like to improve that ratio, with a focus on coaxing the E. coli to produce more of the 3-hydroxy fatty acids for every gram of glucose consumed.

https://phys.org/news/2021-11-sugar-loving-microbes-power-future-ca...

Comment by Dr. Krishna Kumari Challa on November 22, 2021 at 9:42am

Brief period of 'blindness' is essential for vision

 Fixational eye movements are tiny movements of the eye—so small we humans aren’t even aware of them. Yet they play a large role in our ability to see letters, numbers, and objects at a distance.

In a new paper published in Proceedings of the National Academy of Sciences, researchers  further cement the evidence for the important role of these tiny movements. By studying how a type of fixational eye movement called a microsaccade affects the foveola, a small region at the center of the retina, the researchers provide important foundational information that can lead to improved treatments and therapies for vision impairments.

Although the foveola is tiny, it is essential for seeing fine details and conducting everyday tasks such as searching for a friend in a crowd or reading distant road signs while driving. Because the region is so small, however, we need to constantly shift our gaze to allow the foveola to get a full view of the world, similar to rotating a telescope to get a full view of a scene. Unlike when we might rotate a telescope, however, our eyes make most of these gaze shifts, especially the smallest ones, on their own, often beneath our awareness. But the gaze shifts are critical for vision. How well we see at any given moment is tightly linked to how and when we shift our gaze.

The researchers focused on microsaccades, tiny rapid gaze shifts that frequently occur when we’re examining fine details. It’s long been known that vision is transiently impaired during larger gaze shifts, such as those we are aware of making, for instance looking back and forth between two computer screens. This phenomenon of transiently impaired vision is known as saccadic suppression. Until now, however, it was unknown whether a suppression also occurs during microsaccades and whether that would affect visibility in the foveola.

The researchers recorded microsaccades in human observers who were engaged in a computer task— searching on the screen for “fleas” jumping in a patch of “fur,” a task that resembles social grooming in primates.

What the researchers found was surprising. 
Immediately before and immediately after participants’ gaze shifted, the participants could not see the fleas, even when they were looking directly at them.

Researchers observed that microsaccades are accompanied by brief periods of visual suppression during which people are essentially blind. However, the researchers found that vision recovered rapidly at the center of the gaze and continued to improve, so that vision was overall transiently enhanced in this region after the saccade.

The results show that the very center of gaze undergoes drastic and rapid modulations every time we redirect our gaze. This brief loss of vision likely occurs so that we do not see the image of the world shifting around whenever we move our eyes. By suppressing perception during saccades, our visual system is able to create a stable percept.

Future research will determine more about this phenomenon and how humans control eye movements to balance the saccadic suppression with the visual enhancement that follows.

https://www.pnas.org/content/118/37/e2101259118

https://www.rochester.edu/newscenter/brief-period-of-blindness-is-e...

https://researchnews.cc/news/10116/Brief-period-of--blindness--is-e...

Comment by Dr. Krishna Kumari Challa on November 22, 2021 at 9:19am

The intestinal microbiota shapes gut physiology and regulates enteric neurons and glia

Comment by Dr. Krishna Kumari Challa on November 21, 2021 at 11:27am

Probing the mystery of how stem cells age

Comment by Dr. Krishna Kumari Challa on November 20, 2021 at 11:37am

Artificial lights are disrupting firefly mating, putting them on the road to extinction

Light pollution impacts mating success and courtship behavior in fireflies, says recent study.

According to a 2019 study, artificial light impacts fireflies in a big way. Fireflies find mates through a courtship process that involves flashing their “lights.” And not just any light: the courting process involves a series of flashes, which are unique to each male and female. Females will choose their mate based on their unique flashing patterns. The females, in turn, will start a flashing “dialogue” with the mate of their choosing. It’s an amazing sight to see.

So how does this courtship process clash with the lights we keep on at night? Fireflies rely on light to communicate, which has led scientists to wonder if light pollution impacts them in some way. Prior studies by the researchers confirmed this, as well as a substantial body of research. So the next logical question, and the one that the researchers tackled, was how this lighting impacts fireflies at the most basic level: courtship.

In these lighted zones, the fireflies were less likely to engage in courtship flashes, and mating success was reduced. The researchers also investigated whether light pollution affected predator-prey relationships, but no significant impact was found.

Outdoor LED lighting spaces, like the one used in this study, can also act as demographic traps, say the researchers. That means that immigration (or the amount of fireflies coming into the area) far exceeds emigration (the amount of fireflies leaving the area) – meaning that fireflies, barring other circumstances, will stay in the lit areas. While the fireflies may be loving the bright LED lights, the lighting affects courtship behaviors, which are significantly reduced, and also likely reduces mating success.

Fireflies are attracted to light but this light “sucks” them in. It’s like how a warm, cozy house is where you want to be on a cold winter day. It attracts you and you don’t want to leave. In the same way, fireflies are attracted to our bright LEDs and don’t want to leave the light. More fireflies enter the area, and then leave. They are attracted to it like a trap. But, like how it’s not healthy for us to stay home all the time, it’s not healthy for fireflies to stay attracted to this light. Fireflies rely on ambient light cues to know when to start courtship flashing, but when the environment is always lit, there is a problem. Courtship behaviors go down and breeding success is also likely to go down.

This is a huge problem – light pollution is one of the fastest growing types of environmental degradation

https://next.massivesci.com/articles/artificial-light-led-impacts-f...

**

Comment by Dr. Krishna Kumari Challa on November 20, 2021 at 10:55am

Frozen turkeys—or any kind of frozen meats, for that matter—contain a lot of ice. Raw meat can be anywhere from 56% to 73% water. If you have ever thawed a frozen piece of meat, you have probably seen all the liquid that comes out.

For deep-frying, cooking oil is heated to around 350 degrees Fahrenheit (175 C). This is much hotter than the boiling point of water, which is 212 F (100 C). So when the ice in a frozen turkey comes in contact with the hot oil, the surface ice quickly turns to steam.

This quick transition is not a problem when it happens at the very surface of the oil. The steam escapes harmlessly into the air.

However, when you submerge a turkey into the oil, the ice inside the turkey absorbs the heat and melts, forming liquid water. Here is where the density comes into play.

This liquid water is more dense than the oil, so it falls the bottom of the pot. The water molecules continue to absorb heat and energy and eventually they change phases and become steam. The water molecules then rapidly spread far apart from one another and the volume expands by 1,700 times. This expansion causes the density of the water to drop to a fraction of a percent of the density of the oil, so the gas wants to quickly rise to the surface.

Combine the fast change in density together with the expansion of volume and you get an explosion. The steam expands and rises, blowing the boiling oil out the pot. If that weren't dangerous enough, as the displaced oil comes into contact with a burner or flame, it can catch fire. Once some droplets of oil catch on fire, the flames will quickly ignite nearby oil molecules, resulting in a fast-moving and often catastrophic fire.

Every year, thousands of accidents like this happen. So, should you decide to deep-fry a turkey for this year's Thanksgiving, be sure to thoroughly thaw it and pat it dry. And next time you add a bit of liquid to an oil-filled pan and end up with oil all over the stove, you'll know the science of why.

https://theconversation.com/why-do-frozen-turkeys-explode-when-deep...

Part 3

**

• ‹ Previous
• 1
• …
• 320
• 321
• 322
• 323
• 324
• …
• 852
• Next ›
• Page