Friends share intestinal flora丨Tech Weekly

Compiled by Zhou Shuyi and Wang Xiang

New study proves crabs feel pain

It has long been believed that decapod crustaceans such as crabs, shrimps, and crayfish have no sense of pain, so even if they are put into a pot and heated, they will not feel pain. Is this really the case? A study recently published in Biology has found for the first time based on electrophysiological evidence that crabs can also feel pain - they transmit painful stimuli to the brain and have clear neural responses to them.

Pain is a complex physiological process. Although previous studies have observed that crustaceans will have withdrawal reflexes and defensive behaviors after being exposed to harmful external stimuli, avoiding harm may only be a reflex reaction of animals and is not directly equivalent to experiencing pain.

Electrodes measuring brain activity are attached to a shore crab, which is then mechanically and chemically stimulated. | Eleftherios Kasiouras

In the new study, researchers applied acetic acid to the eyes, antennae, and leg joints of common shore crabs (Carcinus maenas), or applied mechanical stimulation (von Frey test), and recorded their EEG signals during this period. The results showed that after being exposed to harmful stimulation, the crab's brain activity increased; when the same part was exposed to the smell of food or a drop of sea water, the central nervous system did not detect any response. The study believes that this shows that there are pain receptors in various parts of the crab's body that can send some form of pain signals to the brain without responding to non-painful stimuli. The study also found that the pain caused by physical stimulation is shorter and more intense than chemical stimulation.

The authors suggest that other crustaceans, such as shrimp and crayfish, have similar body structures and nervous systems to crabs, and are likely to sense pain in a similar way. Perhaps the next time you cook shrimp or crab, it would be best to give it a "painful" taste.

Results of China's largest-scale COVID-19 survey released

A recent online survey of more than 74,000 Chinese residents by The Lancet Regional Health-Western Pacific showed that 10% to 30% of COVID-19 patients reported symptoms of "Long COVID". This is also the largest "Long COVID" survey in China to date.

This retrospective study used an online questionnaire survey to investigate the COVID-19 infection status and "COVID-19" symptoms of 74,075 Chinese residents in the past year from November 22, 2023 to January 24, 2024, and finally obtained 68,200 valid questionnaires.

"Long COVID" refers to symptoms that persist or new symptoms appear three months after the initial COVID-19 infection, and these symptoms last for at least two months without other explanation. About 140 million people worldwide are troubled by "Long COVID". It can affect multiple organ systems, causing cognitive and emotional disorders. Typical symptoms include fatigue, discomfort after exercise, brain fog, dizziness, gastrointestinal symptoms, palpitations, loss of libido, impaired sense of smell or taste, thirst, chronic cough, chest pain, hair loss, etc. Anyone infected with COVID-19 may suffer from "Long COVID", and the incidence varies greatly, ranging from 10% to 60%. Vaccination with the COVID-19 vaccine has been shown to significantly reduce the risk of "Long COVID".

The analysis showed that about 10% to 30% of patients had experienced one or more symptoms of "long COVID", and the most common symptoms (incidence at 3 months) included fatigue (30.53%), memory loss (27.93%), decreased motor ability (18.29%), cough/sputum (18.83%), thirst/dry mouth (18.06%), sleep disorders (17.41%), and brain fog (16.87%). Among people who were infected only once, symptoms such as fatigue (24.85%), memory loss (18.11%), and decreased motor ability (12.52%) were less common.

The study also found that women are more likely to experience "long COVID". There are obvious differences in symptoms among different age groups, but symptoms such as sleep disorders and muscle/joint pain are more common in the elderly. The incidence of "long COVID" is higher in residents in northern China, and the study believes that this may be related to temperature differences.

Risk factors for "long COVID" include underlying diseases, drinking, smoking, and the severity of acute infection. Repeated infections generally have milder acute symptoms, but the incidence and severity of "long COVID" are higher. Vaccination, especially multiple booster shots, can significantly reduce long-term symptoms by 30% to 70%. According to self-reports of COVID patients, bacterial, influenza, and mycoplasma infections are also more common, and 8% to 10% of patients believe that COVID has aggravated previous chronic diseases or caused new complications.

Amber discovered in Antarctica for the first time

Amber has been found in Antarctica for the first time, according to a new study published in the journal Antarctic Science, suggesting that around 90 million years ago, climate conditions in Antarctica allowed the survival of trees capable of producing resin.

In 2017, the research team took the Polaris research vessel and successfully collected a sediment core sample containing amber from the seafloor sediment layer at a depth of 946 meters in the Amundsen Sea using the seafloor drilling device MARUM-MeBo70. The sample was named "Matsushima Amber". The Amundsen Sea is located on the edge of West Antarctica at 73.57° south latitude and 107.09° west longitude.

The team first air-dried the samples, then cut them into tiny slices about 1 mm in diameter, and separated the amber from them. They found what may be the remains of ancient tree bark. The high quality of Antarctic amber indicates that it was buried at a shallow depth, because as the burial depth increases, amber will dissipate under the action of thermal stress. The research team believes that this discovery provides a new perspective for understanding the forest ecology of the Cretaceous period around Antarctica.

"By analyzing amber fragments, we can get a direct idea of ​​what the environment was like in West Antarctica 90 million years ago," said the researcher. "At some point in history, climate conditions on all seven continents allowed the survival of resin-producing trees. Our goal now is to learn more about this forest ecosystem - whether it was destroyed by fire and whether we can find traces of life in amber. This discovery provides us with a more direct way to look back into the past."

UN: About 1.3 million new HIV infections expected in 2023

December 1 is World AIDS Day. A report released by the United Nations AIDS Program on November 26 showed that 630,000 people died of AIDS-related diseases in the world in 2023, and about 1.3 million new people were infected with HIV.

The report shows that there are about 39.9 million people infected with HIV worldwide, an increase of 900,000 from 2022, of which 9.3 million people still cannot receive treatment. In at least 28 countries, the number of new HIV infections is still rising. In 2023, an average of 570 women aged 15 to 24 will be infected with HIV every day. In at least 22 countries in eastern and southern Africa, the risk of HIV infection for women in this age group is three times that of their male peers.

Winnie Byanyima, Executive Director of the United Nations AIDS Program, said that depriving women of their right to education, condoning gender-based violence, and medical inequality... These human rights violations will hinder AIDS treatment and lead to the spread of the virus. "To protect everyone's health, we must protect everyone's rights."

Alexandra Calmi, head of the AIDS program at the Geneva University Hospital, said that life-saving drugs and treatments are not just commodities, but also public welfare. Relevant resources need to be promoted urgently to achieve universal coverage.

The most energetic cosmic ray electrons ever detected

A research team used the High Energy Stereoscopic Telescope (HESS) to detect the highest energy cosmic ray electrons to date (40 TeV). The new research narrowed the candidate range of nearby cosmic ray electron sources and filled the previously unexplored energy range. It is expected to continue to serve as a reference benchmark in this research field in the next few years. The relevant paper was published in Physical Review Letters on November 25.

HESS | Wikimedia Commons

Cosmic rays are charged particles from outer space, and their origin is one of the most important frontier scientific issues in contemporary astrophysics. Due to the existence of the random magnetic field of the Milky Way, the direction of cosmic rays is constantly deflected during propagation, and their original direction information is quickly lost. The intensity of galactic cosmic rays observed on Earth is highly isotropic, and it is difficult to obtain the origin of cosmic rays by measuring their direction. In terms of composition, cosmic rays are mainly composed of atomic nuclei, 86% of which are hydrogen nuclei (protons), 12% are helium nuclei, 1% are carbon, nitrogen, oxygen and iron nuclei, and 1% are electrons. The energy of cosmic ray electrons exceeds 1 TeV (1 TeV = 10¹² eV, which is 1 trillion times higher than the energy of visible light), providing important information for understanding the high-energy processes occurring in the Milky Way.

In the new study, researchers analyzed a large amount of data collected by four HESS telescopes over more than a decade. They improved particle identification technology and adopted a new and more efficient screening algorithm to successfully separate the cosmic ray electron signal from the background. Based on this, a wide cosmic ray electron energy spectrum was drawn, with energies up to 40 TeV. In contrast, the energies of cosmic ray electrons detected in the past were all below 5 TeV. There is a clear kink in the energy spectrum around 1 TeV, and new research shows that this kink is sharper than previously expected. The authors of the paper said: "This is an important result. We can conclude that the detected cosmic ray electrons are likely to come from a very small number of sources near our solar system, with a maximum distance of thousands of light years, which is a very short distance compared to the Milky Way."

Friends share gut flora

Diet, medicine, social interaction, environment... Microorganisms are silently changing us, and we are also changing us. The relationship between them and the human body may be far more intimate and profound than we think. A study published in Nature on November 20 showed that members of the same social circle share microorganisms, and the more they interact, the more similar their intestinal microbial composition is, even between non-family members.

The researchers traveled to the jungles of Honduras, a Central American country, to map the social relationships of 1,787 adults in 18 remote villages, where villagers interact primarily face-to-face and are less exposed to processed foods and antibiotics that can disrupt the microbiome, and to analyze their microbiomes.

Researchers mapped social relationships and collected microbiome data from residents of 18 remote villages in Honduras. | Human Nature Lab at Yale

The study recorded 2,543 types of microorganisms and 339,137 strains (subspecies) of microorganisms. The analysis showed that even if other factors such as diet, water source and medicine were excluded, the microbiota between members of the same social circle would show significant similarities. For individuals (including couples) living in the same house, the similarity of intestinal microbiota was as high as 13.9%; for individuals who did not live together but were accustomed to spending their leisure time together, the similarity was 10%; in contrast, for individuals in the same village who did not interact much, the similarity was only 4%. This similarity is related to the frequency and way people socialize (such as handshakes, hugs, and kisses). "In fact, in the villages we studied, microbiome similarity is the most powerful factor in predicting people's social relationships, surpassing wealth, religion and education." It is worth noting that the results of this study are for microbial strains, not a wider range of microbial species, so this similarity is more likely to come from the interpersonal transmission of microorganisms rather than by chance.

In addition, the study found evidence of the existence of a microbial "transmission chain" - the similarity of the microbiota between friends of friends was also higher than the random level. Compared with individuals on the edge of the social network, the intestinal microbes of "social celebrities" are more similar to those of other villagers. The study also found that specific microbes will cluster corresponding to different social circles in the village. "Drama, rowing, physics... You will develop different circles of friends around these interests and hobbies. Our research shows that members of the circle may be connected in unexpected ways, even through their microbiota."

The researchers said the findings have both negative and positive sides. For example, certain disease risk factors associated with microbes, such as high blood pressure and depression, may be spread, but the health benefits of beneficial bacteria can also be transferred through social networks. People should not refuse to socialize because they are afraid of "infecting" others' microbes - social interactions can spread healthy microbes and bring many other benefits. "Close contact is not bad for us. On the contrary, it's beneficial!"

International Telecommunication Union: About one-third of the world's population still has no access to the Internet

The International Telecommunication Union released a report on November 27 saying that the number of global Internet users will further increase in 2024, estimated to reach 5.5 billion, but a stubborn digital divide still exists, with about one-third of the population still unable to access the Internet.

The annual report, titled "Facts and Figures 2024," shows that an estimated 5.5 billion people worldwide will use the Internet in 2024, an increase of 227 million from the previous year, accounting for 68% of the total population. In contrast, an estimated 2.6 billion people, or 32% of the total population, will not have access to the Internet, of which 1.8 billion live in rural areas.

The report shows that Internet use is closely related to the level of development. In 2024, an estimated 93% of the population in high-income countries will use the Internet, while this proportion will be only 27% in low-income countries. An estimated 83% of urban residents use the Internet, while the proportion in rural areas is less than half (48%). Four-fifths of the global population over the age of 10 have a mobile phone, but this proportion is only 56% in low-income countries. In addition, 5G network coverage is estimated to reach 84% in high-income countries, while it is only 4% in low-income countries. The average mobile broadband traffic per person per month in high-income countries (16.2 GB) is about eight times that of low-income countries (2 GB).

Doreen Bogdan-Martin, Secretary-General of the International Telecommunication Union, said that this report tells the story of two realities in the digital field between high-income countries and low-income countries, and the most vulnerable groups have difficulty accessing information, education and employment opportunities online. In this interconnected world, real progress is to ensure that everyone moves forward together. (Xinhua)

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