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Written by | Huang Yuxiang Boiling water cabbage egg fried rice
Editor-in-charge | Yu Qi
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1
Coronavirus makes people smell out of order? The reason was found
Image source: hms.harvard.edu/ olfactory failure is a common symptom after suffering from COVID-19, but the mechanism behind it is very confusing: the new coronavirus SARS-CoV-2 mainly infects host cells through the ACE2 receptor on the surface of the cell membrane, and this receptor happens to be very low in the olfactory neuron responsible for olfactory sensation. Previous studies have also shown that neuronal cells are indeed difficult to be infected by the new crown virus, so how to explain the symptoms of olfactory failure shown by new crown infected people? A recent work published in Cell explains this. By studying the olfactory epithelial tissue of hamsters and humans, the authors found that although SARS-CoV-2 infection is difficult to disrupt the function of olfactory neurons through direct infection, it can infect and destroy the pillar cells that provide "replenishment" to olfactory neurons. The researchers speculate that the signal that the function of pillar cells is infected by SARS-CoV-2 will be transmitted to olfactory neurons, thereby reducing the expression of olfactory receptor molecules.
Article links:
https://www.sciencedirect.com/science/article/pii/S0092867422001350
2
Why don't hibernating animals starve to death?
Image credit: pixabay
Image credit: Science News
Swipe left to see how the hibernating animals represented by squirrels can turn on the "ultra-long standby" state during the food shortage season? In order to explore this problem, researchers at the University of Wisconsin conducted nitrogen isotope labeling experiments in active and hibernating squirrels to find the mechanism of maintaining protein content in the body during hibernation. They were surprised to find that when squirrels are hibernating, the urea in the blood does not form urine directly through the kidneys, but re-enters the digestive system, which in turn is broken down into ammonia and carbon dioxide by the gut microbiome that expresses urease. The gut microbes also recycle the nitrogen in the ammonia molecules, synthesize them into amino acids, and eventually return some of them to the squirrel host during hibernation. In this way, squirrels can minimize muscle loss during hibernation.
https://www.science.org/doi/full/10.1126/science.abh2950
3
Who is preferred for chicken thighs and mates? Humans and animals give the same answer
Image source: pixabay In the dating bridge of Valentine's Day, a hearty dinner is always essential. New research in Nature has found that the relationship between "full food" and "lust" is not unique to humans. In hungry males, eating is a priority over courtship, and protein-rich foods quickly reverse that order. The researchers experimented with fruit flies and found that after a meal, the intestines release diuretic hormone 31 (Dh31), a signaling molecule of the chemical messenger type of neuropeptide that can excite brain neurons through the circulatory system within minutes, rearranging the priorities of two evolutionary competing behaviors of eating and courtship: in the absence of Dh31, foraging takes precedence over courtship, and when Dh31 is released from the intestine, courtship takes precedence over foraging. Therefore, when they are full, the attention of these experimental subjects will quickly turn to courtship.
https://www.nature.com/articles/s41586-022-04408-7
4
What is the core of the Earth? New research from the Chinese Academy of Sciences: a bunch of superions
The Earth's core pressure and temperature are extremely high, consisting of a liquid outer core and a solid core. The formation and growth of the core is due to the solidification of liquid iron at the core boundary, and the density of the core is lower than that of pure iron, and scientists have been exploring the reasons for this. A joint research team from the Institute of Geochemistry of the Chinese Academy of Sciences found that the core of the earth is not an ordinary solid, but is composed of a solid iron lattice and liquid light elements, which is also known as a superionic state. Using computational simulations of high pressure and high temperature based on quantum mechanical theory, the researchers found that some ferroalloys transformed into a superionic state under core conditions, light elements became disordered and diffused in the lattice like liquids, while iron atoms remained in order, vibrating around their lattice, forming a solid iron frame. In addition, a long-term mystery about the kernel is that it is quite soft and the shear wave velocity is quite low. The researchers calculated the seismic velocity of these superioned ferroalloys and found a significant decrease in shear wave velocity. This result is consistent with seismological observations.
Images & Article Links:
https://www.nature.com/articles/s41586-021-04361-x
5
How do severed limbs regenerate? The study of the clawed toad offers a new direction
Image source: wikipedia.org after a large-scale human injury will be covered by the formation of scar tissue, for patients who have lost limbs due to trauma and other reasons, it is not possible to regain a new limb through natural healing. Recently, scientists from the United States have made new progress in this field. The researchers selected adult Xenopus laevis that could not regenerate limbs in its natural state, and they designed a wearable device for the mutilated Xenopuspus that could be fastened to the wound: the BioDome, which contained a silk protein gel containing a mixture of five small molecule drugs, which was worn 24 hours after amputation and removed. The appearance of the limbs of the clawed toad is observed in the 9th month after treatment, while at 18 months, the appearance of the limbs is very similar to that of normal limbs. This newborn limb can not only respond to external stimuli, but also the clawed toad can use it for swimming exercises, unfortunately, the end toes have not grown bones. The authors say the next step will be to test on mammals and explore the secrets of human limb regeneration.
https://www.science.org/doi/10.1126/sciadv.abj2164
6
The Netherlands is experiencing a more dangerous HIV mutation
Image source: pixabay RNA viruses including COVID-19 are prone to mutations during replication, evolving more transmissive and destructive mutant strains of the virus. A recent study suggests that another RNA virus, the HIV virus, has evolved more dangerous mutants. A team of researchers from the University of Oxford discovered a completely new mutant strain of HIV (VB mutant strain) in Europe, with 15 of the 17 infected patients from the Netherlands. Compared with other HIV strains, VB mutant strains have a higher viral load in the host, are more destructive to immune cells, and are more infectious. Because mutations in the genome caused changes in more than 200 amino acids, researchers have not yet determined the cause of the increased virulence and infectivity of the VB mutation strain. Although the immune system recovery and survival rate of patients infected with VB mutant strains after treatment is similar to that of patients infected with other HIV, the authors recommend that patients should receive treatment as early as possible due to their ability to damage immune cells.
https://www.science.org/doi/10.1126/science.abk1688
Plate editor| Ginger Duck