In February 7, 2020, the essence of Science magazine, Chinese scientists published two Science papers in the same period.

February 12, 2020 / BIOON / - -- a new issue of Science Journal (February 7, 2020) is published this week What are the highlights of its research? Let Xiaobian come together The picture is from science journal 1 Science: scientists from Zhejiang University have revealed that microglia play a key role in memory regulation Doi: 10.1126/science.aaz2288 microglia are the resident immune cells in the brain They are the first responders, always looking for the place where errors occur They make up about 10% of our brain cells In the past, they were thought to be passive bystanders in the brain, working only when injured or infected These cells were first observed by Rudolf Virchow, a German doctor, in 1856 They were later called microglia, meaning "little glue" Now, in a new study of mice, researchers from the medical school of Zhejiang University in China have found that microglia may actually be a key factor in memory retention If the same effect is found in humans, it could lead to better treatments for amnesia, Alzheimer's and other memory impairing diseases The relevant research results were published in the Science Journal on February 7, 2020, and the title of the paper is "microglia mediate forcing via complex dependent synthetic elimination" This new study shows that microglia are closely related to memory maintenance in mice Mice experienced the fear conditioning task, so that when they were placed in an environment where they remembered experiencing something negative - in this study, when they were given a small shock to their feet - they would stay still because of fear Over the course of 35 days, the mice 'freeing response decreased from 70% to 20%, indicating that they had forgotten the negative effects of this particular environment Then, using a series of scientific tools, including genetic, pharmacological and biochemical methods, the authors removed microglia from the brains of these mice and carried out experiments again The results showed that the removal of microglia changed their response to this task About 50% of the mice (20% in the above experiments) remembered the negative experience even after a similar period of time Based on this, a hypothesis is put forward that microglia is the key to consolidate these memories and support which memories are forgotten and which memories are kept The study continued to find that it was the synaptic rearrangement within these mice that led to this observation 2 Science: subvert the routine! To reveal the new mechanism of mosquito finding human bite: doi: 10.1126/science.aay9847; Doi: 10.1126/science.aba4484 in a new study, Paul Garrity, a biology professor at Brandeis University, Chloe greppi, a doctoral student, Willem Laursen, a postdoctoral researcher, and several other colleagues reported that they found an important aspect of how mosquitoes use human body temperature to find and bite humans The relevant research results were published in the Science Journal on February 7, 2020, and the title of the paper is "mosquito heat seeking is driven by an advanced cooling receiver" In the experiment, the researchers knocked out the mosquito gene responsible for producing the ir21a receptor Then they put about 60 mutated mosquitoes (i.e knockout mosquitoes) into a shoe box sized container, and put a plate on the back wall of the container They heated the plate to a core temperature close to 37 ℃, and then sprayed a small amount of carbon dioxide into the mosquitoes to imitate human respiration When the non mutant mosquitoes quickly gathered on the plate near 37 ℃ and tried to find food, the mutant mosquitoes largely ignored the plate Without the ir21a receptor, they would no longer be able to direct themselves to the hottest spot nearby In the second experiment, the mosquitoes were placed in a small mesh cage The researchers placed two vials full of human blood on top of the cage, one heated to 22.78 ℃ (room temperature) and the other to 31.1 ℃ (surface temperature of human hands) Compared with the non mutant mosquitoes in the same environment, the mutant mosquitoes' preference for 31.1 ℃ blood decreased According to Garrity, the ir21a receptor is activated whenever mosquitoes move to lower temperatures Since humans are usually warmer than their surroundings, this means that ir21a is silent when mosquitoes approach humans However, if the mosquito deviates from its route and begins to move away from its warm blooded prey, ir21a will be activated and will not be closed until the mosquito changes course 3 Science: how does intercellular communication lead to leukaemia? Doi: 10.1126/science.aaw3242 a new study published in science recently revealed how rogue communication in blood stem cells can lead to leukaemia This discovery paves the way for the development of new targeted therapies that prevent this process When stem cell mutations cause them to produce too many blood cells, blood cancers such as leukemia can occur In response, researchers from the University of York have revealed how these mutations can cause cells to deviate from their normal path of mutual communication, thus causing blood cells to grow out of control In this study, scientists used a super-resolution fluorescence microscope to study how blood stem cells talk to each other in real time They looked at how cells receive instructions from "signaling proteins." The signal protein binds to a receptor on the surface of another cell and then transmits a signal to tell the cell how to respond Further, the researchers found that mutations associated with certain types of blood cancer can cause blood stem cells to become "rogue," that is, able to communicate without cytokines Professor Ian Hitchcock, from the Biomedical Research Institute of York University and the Biology Department of York University, said: "our bodies produce billions of blood cells every day by signaling to each other Cytokines act as factory supervisors, regulating this process and controlling the development and proliferation of different blood cell types Our research has revealed a previously unknown mechanism, that is, how the mutation of cells leads to signal transduction without the regulation of cytokines, leading to the occurrence of leukemia and other blood cancers Understanding this mechanism will contribute to the development of new drugs " 4 Science: key enzyme molecules regulate liver injury in NASH doi: 10.1126/science.aay0542 in the United States, up to 12% of adults suffer from nonalcoholic steatohepatitis (NASH), which is a malignant disease that may lead to cirrhosis or liver cancer In a recent study, researchers at the University of California, San Diego School of medicine revealed the molecular pathway of hepatocyte death during the onset of Nash and effectively inhibited the severity of liver injury in NASH mouse models The results were published recently in science "We know that fatty liver can cause organ inflammation and scar formation, and can develop into cirrhosis, liver cancer and liver failure," said Dr Alan saltiel, director of the Institute of diabetes and metabolic health at the University of California, San Diego The researchers report that this shift is due to inhibition of the increase in AMPK enzyme, a major energy consumption regulator, and caspase-6 activity, which is involved in the regulation of apoptosis, a signal of programmed cell death When AMPK activity is low, the ability of cells to burn calories is reduced, leading to fat storage The team fed mice a high-fat diet and blocked the activity of AMPK in the belief that their fatty liver condition would worsen, but that was not the case The mice developed symptoms of Nash and liver failure "We found that AMPK did not regulate metabolism as much as we thought, but regulated the process from fatty liver to Nash and from Nash to hepatocyte death," saltiel said In this case, AMPK acts as a sensor to control cell death When AMPK activity is lost, cell death is continuously inhibited It has been proved that AMPK can block the activity of caspase-6, so when the activity of AMPK decreases, the activity of caspase-6 is released, which leads to the death of hepatocytes " After a new understanding of the role of AMPK and caspase-6, the team used AMPK activators to reduce caspase-6 activity Although this effect did not prevent fatty liver, it did prevent the progression from fatty liver to Nash and subsequent hepatocyte death The same results occurred when the team used caspase-6 inhibitors 5 Science: a major breakthrough! To reveal the new mechanism of detection of cancer and infection by γ δ T cells doi: 10.1126/science.aay5516 γ δ T cells is very important for protective immune response For 25 years, scientists have been puzzled by the question of how to activate δ T cells In a new study, researchers from the University of Melbourne in Australia and the Olivia Newton John Cancer Institute and other research institutions have made a breakthrough in this issue Relevant research results were published online in the journal Science on January 9, 2020, and the title of the paper is "butyrophilin 2A1 is essential for photoantigen activity by γ δ T cells" The corresponding authors are Dr Andreas behren of the Newton John Cancer Institute in Olivia, Professor Dale Godfrey of the Peter Doherty Institute of infection and immunology at the University of Melbourne and Dr Adam uldrich of the Peter Doherty Institute of infection and immunology The first author of this paper is Marc Rigau, Ph.D student of the Peter Doherty Institute of infection and immunology Dr uldrich explained that it is known that delta T cells respond to small molecules called phosphoantigens produced by bacteria and cancer cells This leads to the activation of these delta T cells and often eradicates the diseased cells These researchers found that the T cell receptor (TCR) molecule located on the surface of δ T cells binds to another molecule called butylophilin 2A1 (btn2a1), which is present on the surface of many different cell types in the whole body 6 Science: Chinese scientists found that the increase of ngr5 level can promote the increase of rice yield doi: 10.1126/science.aaz2046 For rice as a crop, more tillers are needed, i.e branches with grains, and the demand for nitrogen fertilizer is less Unfortunately, for many rice varieties, the number of tillers depends on the amount of nitrogen applied Researchers from the Chinese Academy of Sciences now show that nitrogen status affects chromatin function through histone modification, in which transcription factor ngr5 recruits combed inhibitor complex 2 to the target gene Some of these target genes regulate tillering so that plants will produce more tillers as nitrogen content increases Ngr5 is regulated by proteasome destruction and mediates hormone signal transduction The increase of ngr5 level can promote the tillering and yield of rice, without the need of increasing nitrogen rich fertilizer 7 Science: climate change led to the widespread decline of bumblebee Doi: 10.1126/science.aax8591; doi: 10.1126/science.aba6432 on the one hand, the number of days of extreme high temperature is increasing Soroye et al Analyzed data sets of Bumblebee occurrence throughout North America and Europe, and found that the increase in the frequency of unusually hot weather is increasing the local extinction rate, reducing settlement and site occupation, and reducing species richness in the region, regardless of land use change or conditions With the holding of average temperature