October 18, 2019 Science journal essence

October 27, 2019 / BIOON / - -- a new issue of Science Journal (October 18, 2019) is published this week What are the highlights of its research? Let Xiaobian come together The picture is from science journal 1 Science: new discovery! How are our brain memories stored during sleep? Doi: 10.1126/science.aay0616; doi: 10.1126/science.aaz4534 recently, scientists from the interdisciplinary research center of biology at the French Academy of France have shown that the trigonometric waves produced by our brain during sleep do not become silent with the rest of the cortical region, on the contrary, they will help the formation of long-term memory by isolating a special cluster of neurons The results were published in science on October 18, 2019 When we sleep, the hippocampus spontaneously activates itself by generating signals similar to when we are awake First it sends information to the cortex, which then responds The last is usually followed by a period of silence, so the brainwave is called "triangle wave" Then there's the rhythmic repetition of what's known as the "sleep spindle." These processes are the key to signal reorganization in cortex to form stable memory However, the role of trigonometry in the formation of new memory is still puzzling: why does silence interrupt the information exchange between hippocampus and cortex and the functional reorganization of cortex? In this regard, the author carefully observed the characteristics of triangular wave itself Surprisingly, they found that in the so-called "silent period", the cortex is not completely silent, but a few neurons keep active and form a collection This finding suggests that when all other neurons remain quiet, a small number of activated neurons can perform important functions while avoiding possible interference Furthermore, the authors reveal how spontaneous activation of hippocampus determines which cortical neurons remain active during the trigonometric wave, and reveal the process of information transmission between the two brain structures In addition, the authors suggest that the neurons activated during the duration of the triangle wave are the same as those involved in the task of learning spatial memory during the day In order to prove this, scientists induced artificial triangular waves in rat model to separate neurons related to hippocampal reactivation The results showed that after the correct neurons were isolated, the memory of rats was stable, and the spatial test was successfully completed the next day 2 Science: new methods help to find the cause of rare genetic diseases doi: 10.1126/science.aay0256 recently, scientists from Scripps Research have invented a new genome technology that can be used to track the causes of rare genetic diseases They reported the technology in science The technology takes advantage of the fact that two copies of each gene in the human body, or "alleles," come from the mother and the father, respectively By comparing the activity levels of alleles from maternal and paternal parents in the whole genome, we can further analyze the causes of the disease Using this technique, they revealed the genes responsible for the rare muscular dystrophy Methods developed by Mohammadi et al Use gene transcription data to detect differences in allele activity levels between maternal and paternal parents It is well known that many rare genetic diseases are caused by DNA mutations that affect a single copy of a gene Therefore, comparing the activity of maternal and paternal alleles in the same cell is more sensitive than that of related genes in different patients and healthy people In order to help assess the abnormal activity of alleles, the method calculates the normal range of difference of maternal and paternal allele activity of each gene based on publicly available gene transcription data This method, called aneva-dot (expression variation analysis dose outlier test), can be used to identify whether the expression level of one allele of a few genes in each individual is abnormal Mohammadi and his colleagues used the aneva-dot method to test a group of patients with dystrophic genetic disease and got positive results 3 Science: To explore the adaptive ancient human gene doi: 10.1126/science.aax2083 when migrating from Africa to Europe and Asia, the anatomically modern people and ancient people (such as Neanderthals and denisovans) hybridize The result of this genetic penetration into the recipient population has aroused great interest, especially in the selection of specific ancient genetic variations Hsieh et al Described adaptive structural variation and copy number variation, which may be the target of positive choice for Melanesians Focusing on specific population regions that carry duplicate genes and display excessive amino acid substitutions in the genome provides evidence for genetic novelty generation and one of the mechanisms leading to differentiation between human genomes 4 Science: a pair of cell adhesion molecules control the matching between R7 neurons and DM8 neurons doi: 10.1126/science.aay6727 with the development of Drosophila retina, the subtype of specific color sensitive cells, namely R7 neurons, is randomly designated, even if they need to connect the downstream neurons, namely DM8 neurons, is not randomly designated Courgeon and desplan found that DM8 neurons were actually specified in the subtype and were overproduced Those DM8 neurons that connected the input of R7 neurons survived; those DM8 neurons that could not find a match developed apoptosis A pair of cell adhesion molecules promotes this match Therefore, even if these downstream neurons are not randomly assigned, the random results of R7 neuron differentiation will spread downstream 5 Science: To explore the origin of cell collective contraction doi: 10.1126/science.aay2346; doi: 10.1126/science.aaz1289 is contrary to plants and fungi Animals can deform their bodies by contracting the collective activities of cells Collective contraction is the basis of gastrulation and muscle movement Brunet et et al Reported that as an organism closely related to animals, a kind of choanoflagellate called choanoeca flexa formed cup-shaped groups, which experienced collective contraction, resulting in rapid changes in group morphology Each of these flagellates consists of a single polarized cell In response to the sudden darkness, photosensitive protein triggered the coordinated polarization contraction of the flagellate cells, resulting in population inversion The cellular mechanism that keeps this process conserved between the euflagellates and animals suggests that their last common ancestor can also polarize cell contraction 6 Science: To explore the stable state of photosystem II in photosynthesis doi: 10.1126/science.aax6998; doi: 10.1126/science.aaz4522 oxygen production photosynthesis uses mn4cao5 cluster to extract electrons from water and produce molecular oxygen in oxygen production complex It is a challenge for X-ray free electron lasers to visually observe each chemical state (S0 to S4) and determine the chemical properties and mechanism according to the structure Suga et al Used tandem crystallography at low temperature to capture and analyze the structures of several stable states in the water oxidation process of optical system II The changes around the water clusters have taken place in S2 state, and are ready for the water insertion stage during the transition to S3 state In S3 state, the distance of 1.9 A between two oxygen atoms is very short, which is consistent with the theoretical study of supporting oxygen / oxygen coupling system 7 Science: explore the spatial structure change of species doi: 10.1126/science.aaw1620; doi: 10.1126/science.aaz4520 under the influence of climate change and other human beings, biodiversity is undergoing rapid change Blowes et al Used a large number of time series data from different regions to analyze the global pattern of biodiversity time change Their findings reveal a clear spatial pattern of changes in abundance and composition, with marine taxa (i.e., marine organisms) having the highest rate of change In particular, the tropical ocean area has become a hot spot of species richness loss In view of the fact that human activities are affecting biodiversity on the whole earth in different degrees and directions, these findings will provide a very necessary biogeographical understanding of biodiversity change, thus helping to determine the priority of conservation (BIOON Com)