使用社交账号登陆

当前位置: 主页 > 最新研究

Science论文导读 0908

时间: 2017年09月18日 | 作者: admin | 来源: 未知
Science 20170908 1 【生物】mTOR regulates metabolic adaptation of APCs in the lung and controls the outcome of allergic inflammation mTOR 调控肺部 抗原呈递 细胞 ( APCs ) 的代谢适应,并控制过敏性炎症 Charles Sincl

Science 20170908

 

1 【生物】mTOR regulates metabolic adaptation of APCs in the lung and controls the outcome of allergic inflammation

mTOR调控肺部抗原呈递细胞(APCs)的代谢适应,并控制过敏性炎症

Charles Sinclair and Gayathri Bommakanti et.al

http://science.sciencemag.org/content/357/6355/1014

 

(导读 阿金)APCs占据着不同的解剖组织,但是其组织体内的稳态机制并不清楚。本研究利用小鼠炎症模型,发现mTOR参与调控肺部CD103阳性树突状细胞(DC)和肺泡巨噬细胞的细胞代谢和积聚,由此抑制过敏性炎症。因此,mTOR具有调控APCs在不同体内组织内的代谢适应,影响过敏性炎症的特性。

Antigen-presenting cells (APCs)occupy diverse anatomical tissues, but their tissue-restricted homeostasis remains poorly understood. Here, working with mouse models of inflammation, we found that mechanistic target of rapamycin (mTOR)–dependent metabolic adaptation was required at discrete locations. mTOR was dispensable for dendritic cell (DC) homeostasis in secondary lymphoid tissues but necessary to regulate cellular metabolism and accumulation of CD103+ DCs and alveolar macrophages in lung. Moreover, while numbers of mTOR-deficient lung CD11b+ DCs were not changed, they were metabolically reprogrammed to skew allergic inflammation from eosinophilic T helper cell 2 (TH2) to neutrophilic TH17 polarity. The mechanism for this change was independent of translational control but dependent on inflammatory DCs, which produced interleukin-23 and increased fatty acid oxidation. mTOR therefore mediates metabolic adaptation of APCs in distinct tissues, influencing the immunological character of allergic inflammation.

 

2 【生物】Structure of a symmetric photosynthetic reaction center–photosystem

 

解析对称光合反应中心-光系统的结构

 

Christopher Gisriel et.al

 

http://science.sciencemag.org/content/357/6355/1021

 

Reaction centers are pigment-protein complexes that drive photosynthesis by converting light into chemical energy. It is believed that they arose once from a homodimeric protein. The symmetry of a homodimer is broken in heterodimeric reaction-center structures, such as those reported previously. The 2.2-angstrom resolution x-ray structure of the homodimeric reaction center–photosystem from the phototroph Heliobacterium modesticaldum exhibits perfect C2 symmetry. The core polypeptide dimer and two small subunits coordinate 54 bacteriochlorophylls and 2 carotenoids that capture and transfer energy to the electron transfer chain at the center, which performs charge separation and consists of 6 (bacterio)chlorophylls and an iron-sulfur cluster; unlike other reaction centers, it lacks a bound quinone. This structure preserves characteristics of the ancestral reaction center, providing insight into the evolution of photosynthesis.

 

(导读 郭怿暄)光合作用的反应中心是负责将光能转化为化学能的重要蛋白质复合体。本研究通过解析嗜中温螺旋杆菌反应中心同源二聚体的X射线结构,发现其呈现完美的C2对称,并揭示了其负责电子传递、电性分离的功能亚基。这一对称结构保留了原始反应中心的特点,暗示着高等光合反应中心的异源二聚结构是由原始的对称同源二聚反应中心进化而来的。

 

 

3【物理】Identification of a primordial asteroid family constrains the original planetesimal population

识别原始小行星家族有助于了解原始行星簇的发展史

Marco Delbo et.al

http://science.sciencemag.org/content/357/6355/1026

图片8.png

图片来源:science.sciencemag.org

 

(导读 阿金)识别残余星簇的小星子能够揭开未知小行星家族的大小,有助于了解小行星形成过程中的关键阶段。本研究发现一个距今四十亿年的小行星家族分布在主行星带内部,其中大部分是以前和这些小行星家族没有关系的暗小行星。研究结果有助于进一步识别一些星子的原始小行星,因为它们的数量符合已知的父母星体。

 

A quarter of known asteroids is associated with more than 100 distinct asteroid families, meaning that these asteroids originate as impact fragments from the family parent bodies. The determination of which asteroids of the remaining population are members of undiscovered families, or accreted as planetesimals from the protoplanetary disk, would constrain a critical phase of planetary formation by unveiling the unknown planetesimal size distribution. We discovered a 4-billion-year-old asteroid family extending across the entire inner part of the main belt whose members include most of the dark asteroids previously unlinked to families. This allows us to identify some original planetesimals, which are all larger than 35 kilometers, supporting the view of asteroids being born big. Their number matches the known distinct meteorite parent bodies.

 

 

4【材料】High dislocation density–induced large ductility in deformed and partitioned steels

变形和分层加工后高错位的钢材具有较大延展性

B. B. He et.al

http://science.sciencemag.org/content/357/6355/1029

(导读 阿金)工业中需要材料同时具备高强度和高延展性,然而加工过程产生的线缺陷会降低延展性。本研究成功开发出一种能够在廉价中锰钢中规避上述问题的技术。通过先冷轧后低温回火的变形和分层工艺尽管产生了位错硬化,但是通过强化移动位错和转化控制能保持高延展性。研究结果为进一步开发高强度、高延展性材料提供了新思路

 

A wide variety of industrial applications require materials with high strength and ductility. Unfortunately, the strategies for increasing material strength, such as processing to create line defects (dislocations), tend to decrease ductility. We developed a strategy to circumvent this in inexpensive, medium manganese steel. Cold rolling followed by low-temperature tempering developed steel with metastable austenite grains embedded in a highly dislocated martensite matrix. This deformed and partitioned (D and P) process produced dislocation hardening but retained high ductility, both through the glide of intensive mobile dislocations and by allowing us to control martensitic transformation. The D and P strategy should apply to any other alloy with deformation-induced martensitic transformation and provides a pathway for the development of high-strength, high-ductility materials.

 

5【神经】Behavioral time scale synaptic plasticity underlies CA1 place fields

 

行为时间尺度突触可塑性是CA1位置场的基础

 

Katie C. Bittner, Aaron D. Milstein et.al 

 

http://science.sciencemag.org/content/357/6355/1033

 

Learning is primarily mediated by activity-dependent modifications of synaptic strength within neuronal circuits. We discovered that place fields in hippocampal area CA1 are produced by a synaptic potentiation notably different from Hebbian plasticity. Place fields could be produced in vivo in a single trial by potentiation of input that arrived seconds before and after complex spiking. The potentiated synaptic input was not initially coincident with action potentials or depolarization. This rule, named behavioral time scale synaptic plasticity, abruptly modifies inputs that were neither causal nor close in time to postsynaptic activation. In slices, five pairings of subthreshold presynaptic activity and calcium (Ca2+) plateau potentials produced a large potentiation with an asymmetric seconds-long time course. This plasticity efficiently stores entire behavioral sequences within synaptic weights to produce predictive place cell activity.

(导读 董堃)学习主要由神经元回路内的突触强度的活性依赖性修饰来介导。本研究发现海马区CA1中的位置场是通过与赫布可塑性显著不同的突触增强而产生的。位置场可以通过在单一试验中增强合成电位前后到达的电发放在体内产生。这种可塑性能够有效地存储突触容纳范围内的整个行为序列以产生预测性的位置细胞活性。

 

 

6【生物】Sterilizing immunity in the lung relies on targeting fungal apoptosis-like programmed cell death

 

肺部的抗菌免疫依赖于靶向类似细胞凋亡的真菌程序性细胞死亡

 

Neta Shlezinger et.al

 

http://science.sciencemag.org/content/357/6355/1037

图片9.png 

(导读 郭思瑶)霉菌分生孢子被吸入肺部后一般会被人体清除。而骨髓功能缺陷的个体内孢子会生长为组织内菌丝。通过小鼠活体内真菌监测,本研究发现肺部中性粒细胞可以引发烟曲霉菌类似细胞凋亡的细胞程序性死亡,这种程序性死亡可能由吞噬细胞的NADPH氧化酶引发,而烟曲霉菌合成的抗凋亡蛋白AfBIR1则可以作为拮抗物抑制这一过程。该发现有利于免疫缺陷型患者肺部真菌感染的治疗研究。

 

Humans inhale mold conidia daily and typically experience lifelong asymptomatic clearance. Conidial germination into tissue-invasive hyphae can occur in individuals with defects in myeloid function, although the mechanism of myeloid cell–mediated immune surveillance remains unclear. By monitoring fungal physiology in vivo, we demonstrate that lung neutrophils trigger programmed cell death with apoptosis-like features in Aspergillus fumigatus conidia, the most prevalent human mold pathogen. An antiapoptotic protein, AfBIR1, opposes this process by inhibiting fungal caspase activation and DNA fragmentation in the murine lung. Genetic and pharmacologic studies indicate that AfBIR1 expression and activity underlie conidial susceptibility to NADPH (reduced form of nicotinamide adenine dinucleotide phosphate) oxidase-dependent killing and, in turn, host susceptibility to invasive aspergillosis. Immune surveillance exploits a fungal apoptosis-like programmed cell death pathway to maintain sterilizing immunity in the lung.

 

7【社会】Protecting unauthorized immigrant mothers improves their children’s mental health

 

保护非法移民母亲,改善其子女心理健康状况

 

 

Jens Hainmueller et.al

 

 

http://science.sciencemag.org/content/357/6355/1041

 

(导读 雷鸣)研究人员对出生日期刚好在DACA(暂缓遣返无身份儿童法案)截点前后的儿童进行准实验调研,确认DACA法案明显降低受保护儿童的适应焦虑障碍。研究表明父母的非法身份成为其子女身心健康成长的巨大的阻碍。

 

The United States is embroiled in a debate about whether to protect or deport its estimated 11 million unauthorized immigrants, but the fact that these immigrants are also parents to more than 4 million U.S.-born children is often overlooked. We provide causal evidence of the impact of parents’ unauthorized immigration status on the health of their U.S. citizen children. The Deferred Action for Childhood Arrivals (DACA) program granted temporary protection from deportation to more than 780,000 unauthorized immigrants. We used Medicaid claims data from Oregon and exploited the quasi-random assignment of DACA eligibility among mothers with birthdates close to the DACA age qualification cutoff. Mothers’ DACA eligibility significantly decreased adjustment and anxiety disorder diagnoses among their children. Parents’ unauthorized status is thus a substantial barrier to normal child development and perpetuates health inequalities through the intergenerational transmission of disadvantage.

 

 

8 Acoustic mirrors as sensory traps for bats

[生态] 声反射蝙蝠造成陷阱

Stefan Greif, Sándor Zsebők, Daniela Schmieder, Björn M. Siemers http://science.sciencemag.org/content/357/6355/1045

(导读 李骏感觉陷阱导致动物误判周围环境产生巨大危险本研究发现蝙蝠会将光滑垂直的平面误认为是无障碍的路径不断发生碰撞,可能由平面声反射特性造成。碰撞发生概率定位声波数量时间长短有关因而有必要更仔细地监测具有反射特性潜在危险区域测算该区域蝙蝠的真实死亡

Sensory traps pose a considerable and often fatal risk for animals, leading them to misinterpret their environment. Bats predominantly rely on their echolocation system to forage, orientate, and navigate. We found that bats can mistake smooth, vertical surfaces as clear flight paths, repeatedly colliding with them, likely as a result of their acoustic mirror properties. The probability of collision is influenced by the number of echolocation calls and by the amount of time spent in front of the surface. The echolocation call analysis corroborates that bats perceive smooth, vertical surfaces as open flyways. Reporting on occurrences with different species in the wild, we argue that it is necessary to more closely monitor potentially dangerous locations with acoustic mirror properties (such as glass fronts) to assess the true frequency of fatalities around these sensory traps.

图片10.png 

(图片来源:sciencemag.org

 

 

9【生物】Paneth cells secrete lysozyme via secretory autophagy during bacterial infection of the intestine

 

潘氏细胞在肠道细菌感染期间通过分泌性自噬分泌溶菌酶

 

Shai Bel et.al

 

http://science.sciencemag.org/content/357/6355/1047

 

(导读 郭思瑶)小肠潘氏细胞通过分泌抗菌蛋白阻止细菌入侵。但致病菌可破坏高尔基体干扰分泌。科学家发现细菌感染发生时,潘式细胞可以构建基于自噬的另一条分泌通路,即分泌性自噬通路。该通路由细菌感染导致的潘氏细胞内质网应激引发。在小鼠中,自噬基因Atg16L1突变会破坏此通路,并提高克罗恩氏病患病率。该发现显示了分泌性自噬在肠道防卫上的作用。

 

Intestinal Paneth cells limit bacterial invasion by secreting antimicrobial proteins, including lysozyme. However, invasive pathogens can disrupt the Golgi apparatus, interfering with secretion and compromising intestinal antimicrobial defense. Here we show that during bacterial infection, lysozyme is rerouted via secretory autophagy, an autophagy-based alternative secretion pathway. Secretory autophagy was triggered in Paneth cells by bacteria-induced endoplasmic reticulum (ER) stress, required extrinsic signals from innate lymphoid cells, and limited bacterial dissemination. Secretory autophagy was disrupted in Paneth cells of mice harboring a mutation in autophagy gene Atg16L1 that confers increased risk for Crohn’s disease in humans. Our findings identify a role for secretory autophagy in intestinal defense and suggest why Crohn’s disease is associated with genetic mutations that affect both the ER stress response and autophagy.