Fossil worm from 550 million years ago discovered

A team of researchers from Virginia Tech analyzed ancient fossils of a small animal species. A discovery that is considered, as defined in the press release, “the most convincing sign of ancient animal mobility.”

Yilingia spiciformis

The researchers classified Yilingia spiciformis (Yiling is the name of the Chinese city where the discovery of the fossil was made). Fossil remains were found in various layers of rock by researchers from the Nanjing Institute of Geology and Palaeontology of the Chinese Academy of Sciences.

The study, published in Nature, describes this animal that dates back to the period of ediacaran. We are talking about a period prior to the age of the dinosaurs. The Yilingia spiciformis was a sort of worm about 10 cm long and about 1.3 cm wide. It could drag its body from the muddy bottom of the ocean to make its way to the mainland. It rested along the road and left long traces. It had 50 body segments, a back and a stomach, and a head and a tail.

Important discovery

This discovery is especially important because, as Shuhai Xiao, professor of Geosciences at Virginia Tech, states, it shows that mobile animals evolved at least 550 million years ago.

The characteristic of mobility that is considered fundamental also for the colonization of the mainland by life, is found in the group of animals called “bilaterans,” a vast group of which we humans are also part and which basically indicates the animals symmetrical bilaterally.

“Their ability to shape the face of the planet is ultimately linked to the origin of animal motility,” says the same researcher in the press release.

The very ability of animals to move intentionally probably marks one of the first decision-making processes among the animals themselves: the paths they took suggest an effort to move to or away from something, a characteristic perhaps dictated by a central nervous system that was beginning to become as sophisticated as that of today’s animals.

“When and how it evolved, animal locomotion defines an important geological and evolutionary context of anthropogenic impact on the Earth’s surface,” Xiao reports.

The research was published in Nature.

Links/Sources:

https://vtnews.vt.edu/articles/2019/09/Science-Shuhai_Xiao_half_billion_animal_trail.html

https://www.nature.com/articles/s41586-019-1522-7

Snake uses top of head to breathe underwater

A group of researchers found that the blue bandaged sea snake (Hydrophis cyanocinctus) uses a complex blood vessel system placed on top of the head to absorb oxygen from the surrounding water when it is immersed. That is a discovery that surprised the researchers themselves.

It is a modified cephalic vascular network (MCVN) that provides an amount of oxygen to the brain that can be considered as complementary during the dive, as Alessandro Palci, an evolutionary researcher at the University of Flinders visiting the University of Alberta, Canada, specifies.

“Basically we have discovered that this sea snake uses the top of its head as a gill to breathe underwater,” reports the researcher to be even clearer. The Hydrophis cyanocinctus is a poisonous snake that lives in the warm tropical waters near the coasts of the Southeast Asia region.

It is not a system that allows snakes to breathe completely underwater: sooner or later they must re-emerge to breathe in the amount of oxygen needed by the brain. What they can get from the water is only a complementary part to allow the snakes to stay a little longer immersed.

However, among the vertebrates breathing from the air, this species of snake can be considered as one of the most “aquatic” in absolute.

Links/Sources:

https://royalsocietypublishing.org/doi/10.1098/rsos.191099

https://en.wikipedia.org/wiki/Hydrophis_cyanocinctus

Alzheimer’s: “hunger hormone” linked to memory according to study

A group of researchers found links between ghrelin, defined as “hunger hormone,” in the brain and memory loss associated with Alzheimer’s disease.

Researchers analyzed brain tissue samples from patients with deceased Alzheimer’s and performed experiments on mice. The study was published in Science Translational Medicine.

Grelin is called “hunger hormone” because it has the task of sending signals to the brain to balance the energy supply and thus also the ingestion of new food. It plays a strong role in appetite but, as other studies have shown, it is also linked to learning and memory.

In a healthy hippocampus, the area of the brain crucial for learning and memory, ghrelin binds to certain dopamine receptors to form a protein complex that maintains a balanced level of communication between brain cells and therefore also memory itself.

In this study, researchers found that in the hippocampus beta amyloid binds to ghrelin receptors and this blocks the latter’s ability to bind to dopamine receptors.

Heng Du, associate professor at the University of Texas and one of the authors of the study, comments on the results of the research: “Our hypothesis is that this dissociation between the receptors of ghrelin and dopamine may be what is affecting cognition in Alzheimer’s patients. Since the brain loses the function of ghrelin receptors due to beta amyloid, the body tries to compensate by increasing ghrelin production and the number of ghrelin receptors. But the amyloid prevents the functioning of the receptors.”

The same researcher adds that, based on these results, Alzheimer’s itself could be linked to the resistance of ghrelin.

Links/Sources:

https://www.utdallas.edu/news/research/hunger-hormone-memory-alzheimers-2019/

https://stm.sciencemag.org/content/11/505/eaav6278

New study solves an old mystery of the tyrannosaurus

A new study, produced by researchers from various American universities, has analyzed the two large holes in the skull of Tyrannosaurus Rex and comes to unexpected conclusions.

This area of the head of these ravenous dinosaurs, called the back of time window, has been a mystery for a long time. According to the main theory developed by paleontologists, these holes were full of muscles that helped the movement of the jaw.

However, Casey Holliday, professor of anatomy at the School of Medicine at the University of Missuori, had some doubts and decided to analyze again this strange anatomical conformation that characterizes the tyrannosaurs many other species of dinosaurs and arcosaurs. It all started when the researcher found strange the anatomical conformation proposed by the theory: the muscle would rise from the jaw, turn a 90° and then pass along the top of the skull.

Using the thermal imaging technique and examining alligators from a Florida zoo, Holliday and colleagues believe they have solved the mystery: the holes in the head serve as a “cross-current circulatory system,” as Kent Vliet, a researcher at the Department of Biology at the University of Florida, also employed in the study, says. This area of the skull was used to keep the temperatures of the skull lower, a sort of “internal thermostat” made by a particular vascular structure combined with adipose tissue.

Studying alligators, in fact, the researchers noted that when there were periods with lower temperatures, the thermography analysis showed large hot spots in the area of these holes and this indicated an increase in temperature. However, during the same day the holes appeared darker, as if they had been closed to keep the area cooler.

“Using the anatomy and physiology of today’s animals, we can show that we can reverse the first assumptions about the anatomy of this part of the skull of Tyrannosaurus Rex,” says Larry Witmer, professor of anatomy at the University of Ohio, another author of the study.

Links/Sources:

https://onlinelibrary.wiley.com/doi/abs/10.1002/ar.24218

Zika virus can also attack adult brains and cause memory deficits

The Zika virus, which in recent years has attracted attention not only in the scientific field, has been the subject of research by a group of neuroscientists at the Federal University of Rio de Janeiro, in Brazil.

Zika virus can also infect adult human tissue

Researchers exposed small fragments of adult human brain tissue to the Zika virus in turn isolated from an infected patient. The researchers found that the virus can infect not only immature neurons in the developing brain but can also infect and deposit in adult human tissue. In this way, it can produce new copies and thus infect even larger areas.

Zika virus produces memory deterioration

They then injected the Zika virus into mice’ brains and noticed a deterioration in memory, which persisted even after the virus had been defeated by the body. This thing, moreover, as reported by Claudia P. Figueiredo and Sergio T. Ferreira, who conducted the research together with the virologist Andrea Da Poian, shows that the main areas where the Zika virus replicates in the brain are those responsible for learning and memory processing.

Zika virus causes inflammatory response in the brain

The same researchers have finally shown that infection with the Zika virus causes a strong inflammatory response in the brain of mice and this caused the activation of the microglia, ie the immune cells in the brain.

Fernanda Barros-Aragão, one of the authors of the study, explains this inflammatory response as follows: “Neurons communicate through highly specialized regions called synapses. Surprisingly, we found that the microglia that aberrantly activates on infection from a ZIKV attack attacks and swallows the synapses. This compromises communication between neurons and thus the formation of new memories. Interestingly, when the animals were treated for about a week with anti-inflammatory drugs that could block the activation of the microglia, they recovered their memory.”

Links/Sources:

http://inct-inovamed.cienp.org.br/2019/09/03/press-release-zika-virus-infects-the-adult-human-brain-and-causes-memory-deficits-in-animal-models/

https://www.nature.com/articles/s41467-019-11866-7

Birds that can fly higher than Everest exist: tests confirm it

Special wind tunnel experiments on 19 Indian geese (Anser indicus) were carried out by researchers to understand how high they can fly.

The researchers trained the geese to fly in a wind tunnel wearing various sensors that recorded various types of data including heart rate and blood oxygen level. The same researchers simulated in the wind tunnel the same conditions that can occur at a certain altitude.

These birds have a better heart and lungs than the rest of the birds. Their large, thin lungs allow deep breathing, while the heart allows more oxygen to be pumped into the muscles. Simulating an attitude level similar to the one at the top of Mount Everest, with 7% oxygen, the heart rate and wing beat rate of these animals remained the same.

These birds are able to cool their blood and absorb more oxygen, which compensates for the very fine air level. The birds flew under these reduced metabolic conditions for a few minutes, which shows that they can fly at certain altitudes similar to those above the tip of Everest, although of course the real conditions could be different since it still takes several hours to get to that altitude even by the birds.

However, this research shows that what some mountaineers said when they climbed the summit of Everest, that is to say that they saw birds flying far above their heads, above an altitude of around 6 miles, can be considered a real thing.

Links/Sources:

https://elifesciences.org/articles/44986

Study confirms that humans have shaped dogs brains

New research gives new prominence to the theory that human beings, reproducing in a highly selective way certain behaviors of dogs and promoting the birth and survival of those specimens best suited to their needs, have literally shaped the brain of these animals.

The study was conducted by the researcher Erin Hecht and her colleagues who performed magnetic resonance scans of the brains of 30 breeds of dogs. In addition to confirming large variations in the brain structure of these dogs, the researchers found that the differences were not only related to body size or head shape.

They then created maps of six brain networks each with different functions ranging from social bonding to movement and each associated with at least one behavioral characteristic.

According to the same researchers, studying and understanding the neuroanatomic changes caused by evolution in dogs offers a unique opportunity to understand the relationship between brain structure and behavior.

Links/Sources:

https://www.jneurosci.org/content/early/2019/08/30/JNEUROSCI.0303-19.2019