In November 1, 2019, the essence of Science magazine was revealed by Chinese scientists.

November 18, 2019 / BIOON / - -- a new issue of Science Journal (November 1, 2019) will be published this week What are the highlights of its research? Let Xiaobian come together The picture is from science journal 1 Chinese scientists analyzed the high-resolution three-dimensional structure of African swine fever virus in science journal and revealed its assembly mechanism Doi: 10.1126/science.aaz1439 African swine fever (ASF) was first found in Kenya in 1921 ASF is a highly infectious swine viral disease, and the mortality rate measured according to the highly toxic virus isolate is close to 100% In the past decade, ASF has spread to many countries in the Caucasus, the Russian Federation and Eastern Europe, posing a serious risk of further spread Between January 2019 and September 2019, 26 countries informed the world organization for animal health (OIE) of new or ongoing outbreaks: 13 in Europe, 10 in Asia and 3 in Africa In the absence of vaccine or treatment, the most effective way to control the outbreak is to kill pigs In 2018-2019, more than 30 million pigs were killed It is estimated that the ASF pandemic has caused $2 billion in economic losses to the global pig industry As the virus that causes ASF, African swine fever virus (ASFV) is stable in the environment and can spread quickly and effectively among pigs ASFV targets macrophages, which are monocytes mainly in blood and bone marrow In a new study, researchers from the Institute of biophysics of the Chinese Academy of Sciences, the University of Chinese Academy of Sciences, the Chinese Academy of Agricultural Sciences, Shanghai University of science and technology, Tsinghua University and Nankai University were 30-40 days old, SPF) pig bone marrow cells (PBM cells) were isolated from pigs, and then the ASFV (hlj-2018 strain isolated from pig spleen samples of a farm in China where an ASF epidemic broke out) was proliferated in the primary PBM cells The extracellular ASFV virus particles were purified from the supernatant, and then the virus particles were inactivated with formaldehyde They used cryo em to study the virus particles The average diameter of ASFV virus particles is 260-300 nm, which is much larger than the previous observation (about 200 nm) This may be because the virus particles are incomplete or the samples are dehydrated before the low-temperature electron microscope observation The relevant research results were recently published in the journal Science, with the title of "architecture of African swing feeder virus and implications for virtual assembly" The corresponding authors are Zhigao Bu, director of Harbin Institute of veterinary medicine, Chinese Academy of Agricultural Sciences, Zihe Rao, academician of Chinese Academy of Sciences and Xiangxi Wang, researcher of Chinese Academy of Sciences Like most nuclear large DNA viruses (NCLDV), the size (diameter 250-500 nm) and potential flexibility of ASFV particles limit its structural resolution to less than 10 μ m (one tenth of nanometer) In this new study, the researchers homogenized 43811 ASFV particles and obtained the reconstruction structure of icosahedron ASFV with a resolution of 8.8 Å The three-dimensional reconstruction structure chart clearly shows the structure of all five layers of ASFV, the largest diameter of the capsid (the fourth layer) is 250 nm, the third layer is 70 μ thick lipid bilayer membrane, which is surrounded by the core-shell (the second layer) with a diameter of 180 nm These three layers present an overall icosahedron shape, roughly following the outline determined by the capsid However, due to the loss of some structural features caused by icosahedral homogenization, the density of the outermost outer capsule and the innermost nucleoid is weak Combined with previous experimental observations, structural analysis in this study and findings in this study, these researchers proposed detailed hypotheses to further understand ASFV capsid assembly First, the ability of P49 to bind to the membrane mediates the attachment of the pentahedral complex to the intima, where it recruits the putamen (a) to form the pentahedral core, thereby initiating assembly This is consistent with the in vivo assembly of the coat of the megavirus mivirus, which starts from the top of the quintuple and gradually completes the assembly of the coat Secondly, the skeleton units m1249l with two shell pairs (B-C and B-C) are attached to the five neighbor core At the same time, these skeleton units, the five neighbor core and p17 can move on the inner membrane, thus increasing their chances of forming higher-order assembly Under the guidance of p17, the shell, the skeleton protein m1249l and p17 contribute to the formation of zipper structures, which connect the adjacent five neighbor core and gradually build a polyhedral framework With the formation of polyhedral framework, the shell is filled with symmetrical shell aggregates to complete the shell assembly In this model, the skeleton protein m1249l acts as the skeleton of the capsid framework and determines the size of the capsid In accordance with this, similar fibroins with similar functions were also observed in PRD-1, PBCV-1 and Bam35, indicating the existence of similar assembly pathways 2 Science: to reveal the mechanism of immune system targeting vitamin B12 to neutralize Mycobacterium tuberculosis doi: 10.1126/science.aay0934; Doi: 10.1126/science.aaz4540 in a new study, researchers from the University of Michigan and Harvard University in the United States found a specific mechanism: the immune system uses a "weapon" called itaconate to target Mycobacterium tuberculosis The relevant research results were published in the Science Journal on November 1, 2019, and the title of the paper is "itoconyl COA forms a stable biological in methylalonyl COA mutase and details its activity and repair" It was only recently discovered that when attacked, the immune system produces a large amount of itaconic acid So far, how itaconic acid can disarm the pathogenic bacteria remains a mystery to some extent Mycobacterium tuberculosis is hidden in human immune cells and uses cholesterol to obtain energy for growth and proliferation In the process, the bacteria produce a toxic intermediate called propionate, which must be removed A strategy for eliminating propionic acid relies on vitamin B12 from the human host As early as 60 years ago, people have found a biological active form of this vitamin, called coenzyme B12, which participates in cell metabolism Coenzyme B12 allows very complex chemical reactions to take place in bacteria and human cells because it releases free radicals (i.e unpaired electrons), making very challenging chemical reactions possible In general, free radicals are very unstable and therefore have a short life "In vivo, free radicals can cause cell damage and DNA damage because they are highly reactive," said Dr RUMA Banerjee, co-author of the paper and professor of Biochemistry at the University of Michigan She explained that the free radicals produced by coenzyme B12 are very active to the double free radicals, which raises the question of how the methylmalonyl COA mutase (MCM), which depends on coenzyme B12, can contain and use the double free radicals In the new study, the researchers were able to confirm that itaconic acid CoA, the active form of itaconic acid, blocks the B12 dependent pathway in TB bacteria and prevents them from using propionic acid for growth Banerjee said it acted as a decoy to do this, "inducing the B12 dependent enzyme to use itaconyl COA as a substrate, which then led to one of the free radicals committing suicide." In addition, the itaconyl COA / coenzyme B12 reaction produced a stable double free radical, which could last for more than an hour, rather than disappear rapidly This led the first author of the paper, Dr Markus ruetz of the Department of Biochemistry, University of Michigan, and a team of structural biology led by Dr Markos koutmos of the Department of chemistry, University of Michigan, to cultivate the crystal of this B12 dependent enzyme with stable double free radicals and obtain its three-dimensional structure 3 Science: reveal the mechanism of immune amnesia caused by measles virus infection, highlight the importance of vaccination doi: 10.1126/science.aay6485 Over the past decade, there has been growing evidence that measles vaccines provide protection in two ways: they prevent not only this well-known acute disease, which often sends children to hospitals with symptoms of spotting and fever, but also other infections that appear to be preventable in the long term How is this done? Some researchers suggest that the vaccine can enhance the immune system in an all-round way Others believe the vaccine's broad protection stems from the prevention of measles virus infection itself According to this theory, the virus can damage the immune memory of human body, thus causing so-called immune amnesia By preventing measles virus infection, the vaccine can prevent the body from losing or "forgetting" its immune memory and maintain its resistance to other infections Now, in a new study, researchers from Harvard Medical School, Brigham and women's Hospital, Chen Zengxi School of public health, University of Helsinki in Finland and University of Rotterdam medical center in the Netherlands have provided much-needed answers They found that measles virus removes 11% - 73% of different antibodies These antibodies can protect the human body from viruses and bacteria - from influenza virus to herpes virus, to bacteria that cause pneumonia and skin infection, which means that these antibodies make the human body immune to these pathogens The relevant research results were published in the Science Journal on November 1, 2019, and the title of the paper is "measures virus infection determines preexisting diseases that offer protection from other pathways" Michael Mina (now assistant professor of epidemiology, Chen Zengxi School of public health, Harvard University), the first author and co-author of the paper and postdoctoral researcher of Stephen elledge laboratory, said, "imagine that your immunity to pathogens is like carrying a picture of criminals with you Someone has made many holes in it Then, if you see criminals, it's hard to recognize them, especially if you make a hole in an important identifying feature (such as eyes or mouth) " Ensuring widespread measles vaccination will not only help prevent 1.2 million deaths directly attributable to measles this year alone, but also avoid hundreds of thousands of additional deaths due to long-term damage to the immune system, the authors said 4 Science: shock! For the first time, it was found that the cytoplasm of animal eggs could be broken and reunited Doi: 10.1126/science.aav7793; Doi: 10.1126/science.aaz5635 in a new study, James Ferrell, Ph.D., Professor of Biochemistry, Professor of chemistry and systems biology, Stanford University School of medicine, and Xiangrui Cheng, Ph.D., a postdoctoral researcher, found that the cytoplasm of the cracked eggs of Xenopus laevis spontaneously self assembles into a cellular compartment The relevant research results were published in the Science Journal on November 1, 2019, and the title of the paper is "spontaneous energy of cell like organization in Xenopus egg extracts" It is worth noting that these self-assembled cellular compartments retain the ability to divide and can form smaller compartments Previous studies have shown that some subcellular structures (such as centrosome and