当前共找到 1168 篇文献分享,本页显示第 681 - 700 篇。
681.
惊鸿
(2022-12-29 15:54):
#paper DOI : 10.1126/science.abl6620 Glassfrogs conceal blood in their liver to maintain transparency 20221222 动物的透明体是一种复杂的伪装形式,涉及减少整个生物体的光散射和吸收的机制。在脊椎动物中,获得透明度很困难,因为它们的循环系统充满了强烈减弱光线的红细胞 (RBC)。在此,这个实验团队记录了玻璃蛙如何通过隐藏这些细胞。该实验团队使用光声成像在体内追踪红细胞,表明静息玻璃蛙通过从循环中去除约 89% 的红细胞并将其包装在肝脏中,从而将透明度提高两到三倍。因此,脊椎动物的透明性需要透明组织和从这些组织中“清除”呼吸色素的活跃机制。此外,玻璃蛙能够调节位置、密度。
Abstract:
Transparency in animals is a complex form of camouflage involving mechanisms that reduce light scattering and absorption throughout the organism. In vertebrates, attaining transparency is difficult because their circulatory system …
>>>
Transparency in animals is a complex form of camouflage involving mechanisms that reduce light scattering and absorption throughout the organism. In vertebrates, attaining transparency is difficult because their circulatory system is full of red blood cells (RBCs) that strongly attenuate light. Here, we document how glassfrogs overcome this challenge by concealing these cells from view. Using photoacoustic imaging to track RBCs in vivo, we show that resting glassfrogs increase transparency two- to threefold by removing ~89% of their RBCs from circulation and packing them within their liver. Vertebrate transparency thus requires both see-through tissues and active mechanisms that "clear" respiratory pigments from these tissues. Furthermore, glassfrogs' ability to regulate the location, density, and packing of RBCs without clotting offers insight in metabolic, hemodynamic, and blood-clot research.
<<<
翻译
682.
李翛然
(2022-12-28 21:08):
#paper doi:10.1016/S1473-3099(22)00291-2 Respiratory syncytial virus prevention within reach: the vaccine and monoclonal antibody landscape. Lancet Infect Dis. 2022 Aug 8:S1473-3099(22)00291-2. . 这篇文章非常好的梳理了正在北美和欧洲大杀四方的rsv 病毒疫苗研发情况。 现在国门打开,未来必然是新冠+rsv+流感的轮流爆发,我司准备开一个这个管线。这篇综述写的非常好。 很有参考价值的梳理了技术路线,临床阶段,为我们的布局很有指导性意义。
Abstract:
Respiratory syncytial virus is the second most common cause of infant mortality and a major cause of morbidity and mortality in older adults (aged >60 years). Efforts to develop a …
>>>
Respiratory syncytial virus is the second most common cause of infant mortality and a major cause of morbidity and mortality in older adults (aged >60 years). Efforts to develop a respiratory syncytial virus vaccine or immunoprophylaxis remain highly active. 33 respiratory syncytial virus prevention candidates are in clinical development using six different approaches: recombinant vector, subunit, particle-based, live attenuated, chimeric, and nucleic acid vaccines; and monoclonal antibodies. Nine candidates are in phase 3 clinical trials. Understanding the epitopes targeted by highly neutralising antibodies has resulted in a shift from empirical to rational and structure-based vaccine and monoclonal antibody design. An extended half-life monoclonal antibody for all infants is likely to be within 1 year of regulatory approval (from August, 2022) for high-income countries. Live-attenuated vaccines are in development for older infants (aged >6 months). Subunit vaccines are in late-stage trials for pregnant women to protect infants, whereas vector, subunit, and nucleic acid approaches are being developed for older adults. Urgent next steps include ensuring access and affordability of a respiratory syncytial virus vaccine globally. This review gives an overview of respiratory syncytial virus vaccines and monoclonal antibodies in clinical development highlighting different target populations, antigens, and trial results.
<<<
翻译
683.
魏魏魏
(2022-12-22 21:45):
#paper doi:10.1038/s44184-022-00011-w Mental Health Research (2022), The mental health and well-being profile of young adults using social media. 青(少)年社交媒体的使用历来吸引人的关注,研究者和政策制定者都对社交媒体使用与心理健康的关系都予以重视,然而,社交媒体对青年心理的影响并不为人所知,对他们关系的影响因素也知之甚少,甚至存在误解。当前研究被试广泛选取了Facebook, Twitter, Instagram, Snapchat和YouTube用户,共计有4083人,均为同辈群体。在当前研究中,研究者采用了追踪研究设计。研究者全面测量了抑郁症状、自杀想法、饮食失调、幸福感、生活满意度、感恩和人生意义等表征心理健康的变量,同时测量了自我决定理论中的三个基本心理需要,也测量了社交媒体的使用情况,包括是否使用软件以及使用频率等情况。当前研究最有价值的发现是,不同类型的社交媒体使用并不必然会导致青少年心理健康变好或变坏,结果因使用软件类型和性别等的差异而有所不同。当前研究有助于我们了解此前研究出现不同结果的原因,也有助于我们了解青少年社交媒体使用的情况。
Abstract:
The relationship between mental health and social media has received significant research and policy attention. However, there is little population representative data about who social media users are which limits …
>>>
The relationship between mental health and social media has received significant research and policy attention. However, there is little population representative data about who social media users are which limits understanding of confounding factors between mental health and social media. Here we profile users of Facebook, Twitter, Instagram, Snapchat and YouTube from the Avon Longitudinal Study of Parents and Children population cohort (N=4,083). We provide estimates of demographics and mental health and well-being outcomes by platform. We find that users of different platforms and frequencies are not homogeneous. User groups differ primarily by sex and YouTube users are the most likely to have poorer mental health outcomes. Instagram and Snapchat users tend to have higher well-being than the other social media sites considered. Relationships between use-frequency and well-being differ depending on the specific well-being construct measured. The reproducibility of future research may be improved by stratifying by sex and being specific about the well-being constructs used.
<<<
翻译
684.
张德祥
(2022-12-14 19:10):
#paper https://doi.org/10.1371/journal.pone.0277199 Structure learning enhances concept formation in synthetic Active Inference agents 结构学习 抽象学习 概念学习是人类认知的高级功能,物体和场景关系在推理中互相影响,现在AI还做不到这样的智能认知,这篇论文超结构学习迈出了第一步,而且是在结构学习下链接行动和感知。世界模型的学习和推理 自由能在学习的时间尺度上,从最快的推理,到慢一点的网络参数学习,再到最慢的睡眠离线模型的结构学习,次论文这三个层次都有介绍,核心是最高级的结构学习。在自由能框架下 结构学习如何自然出现。结构学习可以联系都洞察力,让人恍然大悟的时刻。涉及贝叶斯模型选择推理。
Abstract:
Humans display astonishing skill in learning about the environment in which they operate. They assimilate a rich set of affordances and interrelations among different elements in particular contexts, and form …
>>>
Humans display astonishing skill in learning about the environment in which they operate. They assimilate a rich set of affordances and interrelations among different elements in particular contexts, and form flexible abstractions (i.e., concepts) that can be generalised and leveraged with ease. To capture these abilities, we present a deep hierarchical Active Inference model of goal-directed behaviour, and the accompanying belief update schemes implied by maximising model evidence. Using simulations, we elucidate the potential mechanisms that underlie and influence concept learning in a spatial foraging task. We show that the representations formed-as a result of foraging-reflect environmental structure in a way that is enhanced and nuanced by Bayesian model reduction, a special case of structure learning that typifies learning in the absence of new evidence. Synthetic agents learn associations and form concepts about environmental context and configuration as a result of inferential, parametric learning, and structure learning processes-three processes that can produce a diversity of beliefs and belief structures. Furthermore, the ensuing representations reflect symmetries for environments with identical configurations.
<<<
翻译
685.
龙海晨
(2022-12-01 17:34):
#paper Wang L, Jiang D, Zhang L. A thermophilic 8-oxoguanine DNA glycosylase from Thermococcus barophilus Ch5 is a new member of AGOG DNA glycosylase family[J]. Acta biochimica et biophysica Sinica.PMID: 35713316 DOI: 10.3724/abbs.2022072
DNA中的8-氧代胍(8oxoguanine,8oxoG)是一种主要的氧化碱基,对基因组稳定性构成严重威胁。细胞已经进化出8oxoG-DNA糖苷酶(OGG)来抵消8oxoG在DNA中产生的诱变。目前,OGG酶分为三个家族:OGG1、OGG2和AGOG。文章研究发现,来自超嗜热性欧氏菌T嗜酸乳杆菌Ch5的Tb-AGOG能在75-95摄氏度pH9.0的时候去除8oxoG有最大效率。Tb-AGOG是一种双功能DNA糖苷酶,具有糖苷酶活性和AP裂解酶活性。文章阐述了AGOG的作用机制。Tb-AGOG中的残基D41和D229对催化至关重要。
IF:3.300Q1
Acta biochimica et biophysica Sinica,
2022-06-25.
DOI: 10.3724/abbs.2022072
PMID: 35713316
Abstract:
8-Oxoguanine (8oxoG) in DNA is a major oxidized base that poses a severe threat to genome stability. To counteract the mutagenic effect generated by 8oxoG in DNA, cells have evolved …
>>>
8-Oxoguanine (8oxoG) in DNA is a major oxidized base that poses a severe threat to genome stability. To counteract the mutagenic effect generated by 8oxoG in DNA, cells have evolved 8oxoG DNA glycosylase (OGG) that can excise this oxidized base from DNA. Currently, OGG enzymes have been divided into three families: OGG1, OGG2 and AGOG (archaeal 8oxoG DNA glycosylase). Due to the limited reports, our understanding on AGOG enzymes remains incomplete. Herein, we present evidence that an AGOG from the hyperthermophilic euryarchaeon Ch5 (Tb-AGOG) excises 8oxoG from DNA at high temperature. The enzyme displays maximum efficiency at 75°C-95°C and at pH 9.0. As expected, Tb-AGOG is a bifunctional glycosylase that harbors glycosylase activity and AP (apurinic/apyrimidinic) lyase activity. Importantly, we reveal for the first time that residue D41 in Tb-AGOG is essential for 8oxoG excision and intermediate formation, but not essential for DNA binding or AP cleavage. Furthermore, residue E79 in Tb-AGOG is essential for 8oxoG excision and intermediate formation, and is partially involved in DNA binding and AP cleavage, which has not been described among the reported AGOG members to date. Overall, our work provides new insights into catalytic mechanism of AGOG enzymes.
<<<
翻译
686.
小W
(2022-11-30 23:58):
#paper doi:https://doi.org/10.1038/s41577-022-00796-z TGFβ control of immune
responses in cancer: a holistic immuno-oncology perspective TGFβ对癌症免疫反应的控制。作为一种进化上古老的调节细胞因子,TGFβ在免疫系统内外具有多效性功能,其促肿瘤或抗肿瘤免疫活性取决于其来源、剂量、环境和白细胞及其靶点,以及癌症类型和疾病阶段。本文使用小鼠肿瘤模型数据,在 TGFβ对不同免疫细胞调节效应 和 TGFβ在癌症先天免疫中的作用 进行了详细的论述,最后介绍了 TGFβ途径的全身阻断 和 靶向阻断TGFβ途径 两类将 TGFβ 用于癌症免疫治疗的尝试。有意思的一点,在本文介绍的 作用于 TGFβ 的 制剂多 与 其他治疗方式连用 ,而去年的 PD-L1/TGFβ双抗 临床试验全都铩羽而归。
Abstract:
The immune system responds to cancer in two main ways. First, there are prewired responses involving myeloid cells, innate lymphocytes and innate-like adaptive lymphocytes that either reside in premalignant tissues …
>>>
The immune system responds to cancer in two main ways. First, there are prewired responses involving myeloid cells, innate lymphocytes and innate-like adaptive lymphocytes that either reside in premalignant tissues or migrate directly to tumours, and second, there are antigen priming-dependent responses, in which adaptive lymphocytes are primed in secondary lymphoid organs before homing to tumours. Transforming growth factor-β (TGFβ) - one of the most potent and pleiotropic regulatory cytokines - controls almost every stage of the tumour-elicited immune response, from leukocyte development in primary lymphoid organs to their priming in secondary lymphoid organs and their effector functions in the tumour itself. The complexity of TGFβ-regulated immune cell circuitries, as well as the contextual roles of TGFβ signalling in cancer cells and tumour stromal cells, necessitates the use of rigorous experimental systems that closely recapitulate human cancer, such as autochthonous tumour models, to uncover the underlying immunobiology. The diverse functions of TGFβ in healthy tissues further complicate the search for effective and safe cancer therapeutics targeting the TGFβ pathway. Here we discuss the contextual complexity of TGFβ signalling in tumour-elicited immune responses and explain how understanding this may guide the development of mechanism-based cancer immunotherapy.
<<<
翻译
687.
小擎子
(2022-11-30 23:57):
# paper doi:10.1186/s13059-016-0997-x;Genome Biol.2016 Mash: fast genome and metagenome distance estimation using MinHash, Mash工具,用MinHash快速衡量基因组和宏基因组距离。Mash主要实现sketch和dist两个功能,sketch将序列或者序列合集转换为MinHash sketch,可以大幅缩小内存占用,dist计算Jaccard index可以在可控误差范围内近似ANI,且计算效率大大提供。重点是k-mer和s(sketch的size大小)的选择,会影响误差。Mash的特点是计算消耗主要是生成sketch上,sketch一旦生成,上万基因组的相似性比较和聚类几乎是瞬时完成的。
Abstract:
Mash extends the MinHash dimensionality-reduction technique to include a pairwise mutation distance and P value significance test, enabling the efficient clustering and search of massive sequence collections. Mash reduces large …
>>>
Mash extends the MinHash dimensionality-reduction technique to include a pairwise mutation distance and P value significance test, enabling the efficient clustering and search of massive sequence collections. Mash reduces large sequences and sequence sets to small, representative sketches, from which global mutation distances can be rapidly estimated. We demonstrate several use cases, including the clustering of all 54,118 NCBI RefSeq genomes in 33 CPU h; real-time database search using assembled or unassembled Illumina, Pacific Biosciences, and Oxford Nanopore data; and the scalable clustering of hundreds of metagenomic samples by composition. Mash is freely released under a BSD license ( https://github.com/marbl/mash ).
<<<
翻译
688.
Arwen
(2022-11-30 23:56):
#paper doi:10.1001/jamanetworkopen.2022.44049 Poverty, Cortical Structure, and Psychopathologic Characteristics in Adolescence
儿童时期的贫困与青春期内化和外化问题的增加有关,青春期是精神问题的高峰发作期。潜在的神经机制尚不清楚,因为缺乏对贫困、大脑结构和精神症状变化的纵向研究。 目的:探讨家庭贫困与青少年早期精神症状变化之间是否存在脑皮层结构差异的中介作用。本纵向队列研究使用了青少年大脑认知发展研究的基线数据和1年随访数据。美国9到10岁的儿童在2016年9月1日至2018年10月15日期间注册。数据分析时间为2021年8月13日至2022年9月30日。以收入需求比衡量的家庭贫困程度,该比率包含了家庭收入,并根据家庭规模占联邦贫困水平的百分比进行了调整。 主要结果和测量指标是:儿童的皮质表面积,厚度和体积,通过磁共振成像获得。1年随访时,产妇使用儿童行为检查表报告内化和外化问题的结果。分析根据基线精神问题和社会人口学变量进行了调整,包括性别、种族和民族、父母教育水平和研究地点。本研究的结果表明:随着青春期早期的时间推移,儿童贫困与外化问题的增加有关,但与内化问题无关。这种联系是由许多大脑区域的皮质表面积减少所介导的。这些发现强调了潜在的神经生物学机制之间的联系,贫穷和外化问题的出现在青春期早期。
Abstract:
Importance: Childhood poverty has been associated with increased internalizing and externalizing problems in adolescence, a period of peak onset for psychiatric problems. The underlying neural mechanisms remain unclear because longitudinal …
>>>
Importance: Childhood poverty has been associated with increased internalizing and externalizing problems in adolescence, a period of peak onset for psychiatric problems. The underlying neural mechanisms remain unclear because longitudinal studies of poverty, brain structure, and changes in psychiatric symptoms are lacking.Objective: To examine whether structural differences in cortical regions mediate the association between household poverty and change in psychiatric symptoms in early adolescence.Design, Setting, and Participants: This longitudinal cohort study used baseline and 1-year follow-up data from the Adolescent Brain Cognitive Development Study. Children aged 9 to 10 years in the US were enrolled between September 1, 2016, and October 15, 2018. Data analysis was performed from August 13, 2021, to September 30, 2022.Exposures: Household poverty as measured by income-to-needs ratio, which incorporates family income and adjusts for family size as a percentage of the federal poverty level.Main Outcomes and Measures: Mediators were children's cortical surface area, thickness, and volume, obtained using magnetic resonance imaging. Internalizing and externalizing problems at 1-year follow-up were outcomes measured by maternal report using the Child Behavior Checklist. Analyses were adjusted for baseline psychiatric problems and sociodemographic variables, including sex, race and ethnicity, parental educational level, and study site.Results: Of the 7569 children (mean [SD] age, 9.91 [0.62] years; 3970 boys [52.5%]) included in the analysis, 1042 children (13.8%) lived below the poverty threshold between 2016 and 2018. Poverty was associated with increased externalizing symptoms score at 1-year follow-up (b = 1.57; 95% CI, 1.14-1.99), even after adjustment for baseline externalizing symptoms (b = 0.35; 95% CI, 0.06-0.64). The longitudinal associations of poverty with increases in externalizing problems over time were mediated by reductions in surface area in multiple cortical regions that support executive functioning (middle frontal gyrus), decision-making (lateral orbitofrontal cortex), visual processing (fusiform gyrus), auditory processing (transverse temporal gyrus), and emotion and language processing (superior temporal gyrus).Conclusions and Relevance: The findings of this study suggest that childhood poverty is associated with increases in externalizing problems, but not internalizing problems, over time in early adolescence. This association is mediated by reductions in cortical surface area across numerous brain regions. These findings highlight potential neurobiological mechanisms underlying the link between poverty and the emergence of externalizing problems during early adolescence.
<<<
翻译
689.
笑对人生
(2022-11-30 23:55):
#paper doi: 10.1038/s41586-022-05426-1. Schmitt M, Ceteci F, Gupta J, Pesic M, Böttger TW, Nicolas AM, Kennel KB, Engel E, Schewe M, Callak Kirisözü A, Petrocelli V, Dabiri Y, Varga J, Ramakrishnan M, Karimova M, Ablasser A, Sato T, Arkan MC, de Sauvage FJ, Greten FR. Colon tumour cell death causes mTOR dependence by paracrine P2X4 stimulation. Nature. 2022 Nov 16.
研究背景:实体瘤的不断形成和生长依赖于细胞死亡和增殖之间的动态平衡。越来越多的研究表明,肿瘤细胞凋亡的增加会通过旁分泌引起微环境内其他细胞激活,启动组织修复相关机制,最终反而为肿瘤生长提供支持。
科学问题:濒死的肿瘤细胞对邻近细胞究竟产生哪些直接影响,以及这种旁分泌机制是否与化疗耐药有关。
研究结果或结论:(1)在结直肠癌患者来源的肿瘤类器官中,化疗诱导肿瘤细胞死亡的同时,会释放ATP,从而触发邻近细胞中由离子通道受体P2X4介导的mTOR信号通路依赖的促存活机制,这使得存活的肿瘤上皮细胞对mTOR抑制敏感。(2)持续存在的上皮细胞中诱发的mTOR抑制敏感是由于活性氧的产生升高,以及随后对邻近细胞死亡的DNA损伤增加。因此,对化疗处理的细胞,使用针对P2X4受体的抑制剂或mTOR直接阻断剂,可防止诱导S6磷酸化,导致活性氧诱导的大量细胞死亡和明显的肿瘤消退。然而,如果单独使用抑制剂或阻断剂,并不能观察到该现象。相反,清除活性氧可防止肿瘤细胞对mTOR激活的依赖。总的来说,本研究详细阐明了肿瘤细胞死亡对邻近细胞存活一种可能机制,未来可就P2X4这一靶点进行结直肠癌治疗药物的开发。
Abstract:
Solid cancers exhibit a dynamic balance between cell death and proliferation ensuring continuous tumour maintenance and growth. Increasing evidence links enhanced cancer cell apoptosis to paracrine activation of cells in …
>>>
Solid cancers exhibit a dynamic balance between cell death and proliferation ensuring continuous tumour maintenance and growth. Increasing evidence links enhanced cancer cell apoptosis to paracrine activation of cells in the tumour microenvironment initiating tissue repair programs that support tumour growth, yet the direct effects of dying cancer cells on neighbouring tumour epithelia and how this paracrine effect potentially contributes to therapy resistance are unclear. Here we demonstrate that chemotherapy-induced tumour cell death in patient-derived colorectal tumour organoids causes ATP release triggering P2X4 (also known as P2RX4) to mediate an mTOR-dependent pro-survival program in neighbouring cancer cells, which renders surviving tumour epithelia sensitive to mTOR inhibition. The induced mTOR addiction in persisting epithelial cells is due to elevated production of reactive oxygen species and subsequent increased DNA damage in response to the death of neighbouring cells. Accordingly, inhibition of the P2X4 receptor or direct mTOR blockade prevents induction of S6 phosphorylation and synergizes with chemotherapy to cause massive cell death induced by reactive oxygen species and marked tumour regression that is not seen when individually applied. Conversely, scavenging of reactive oxygen species prevents cancer cells from becoming reliant on mTOR activation. Collectively, our findings show that dying cancer cells establish a new dependency on anti-apoptotic programs in their surviving neighbours, thereby creating an opportunity for combination therapy in P2X4-expressing epithelial tumours.
<<<
翻译
690.
na na na
(2022-11-30 23:54):
#paper doi: 10.1186/s13148-021-01210-6. Clin Epigenetics. 2021 Dec 18,Meyer B;Identification of DNA methylation biomarkers with potential to predict response to neoadjuvant chemotherapy in triple-negative breast cancer; 为避免新辅助化疗(NAC)用于三阴性乳腺癌(TNBC)术前的治疗所产生的化学毒性,需要准确的生物标志物来进行个体化预测。作者对术前TNBC活检样本进行了全基因组DNA甲基化分析,找到9个诊断时与NAC反应相关的显著差异甲基化区域(DMRs)。其中4种DMRs与TNBC总生存率显著相关(P < 0.05)。文章的重要意义不仅在于找到了TNBC的新辅助化疗预后标志物,更强调了DNA甲基化作为生物标志物在预测NAC反应方面的潜力。
Abstract:
Neoadjuvant chemotherapy (NAC) is used to treat triple-negative breast cancer (TNBC) prior to resection. Biomarkers that accurately predict a patient's response to NAC are needed to individualise therapy and avoid …
>>>
Neoadjuvant chemotherapy (NAC) is used to treat triple-negative breast cancer (TNBC) prior to resection. Biomarkers that accurately predict a patient's response to NAC are needed to individualise therapy and avoid chemotoxicity from unnecessary chemotherapy. We performed whole-genome DNA methylation profiling on diagnostic TNBC biopsy samples from the Sequential Evaluation of Tumours Undergoing Preoperative (SETUP) NAC study. We found 9 significantly differentially methylated regions (DMRs) at diagnosis which were associated with response to NAC. We show that 4 of these DMRs are associated with TNBC overall survival (P < 0.05). Our results highlight the potential of DNA methylation biomarkers for predicting NAC response in TNBC.
<<<
翻译
691.
cellsarts
(2022-11-30 23:32):
# paper doi:10.1016/j.jmb.2004.09.012;J. Mol. Biol. (2004) 343, 1281–1292;青霉beta-半乳糖苷酶、及其与半乳糖的配合物的晶体结构.Crystal Structures of b-Galactosidase from Penicillium sp. and its Complex with Galactose.b-半乳糖苷酶催化低聚糖中beta(1-3)和beta(1-4)半乳糖键的水解以及酶缩合和转糖基化的逆反应。本文报道了青霉菌beta-半乳糖苷酶及其与半乳糖配合物的晶体结构,是利用SIRAS快速冷冻浸泡技术在1.90 A˚和2.10 A˚精度下分别解析。该120 kDa蛋白的氨基酸序列首先通过实验电子密度图的检测确定,然后通过核苷酸序列分析确定。初步结构比对显示青霉beta--半乳糖苷酶属于糖基水解酶(GHF-35)第35家族。该模型是GHF-35成员的第一个解析出的3D结构。组成该结构的五个不同结构域以beta-半乳糖苷酶以前未见过的方式组合。该配合物与其他来自几个水解酶家族的beta-半乳糖苷酶配合物的比对显示残基Glu200将被鉴定为质子供体,残基Glu299被鉴定为参与催化的亲核试剂。青霉菌b-半乳糖苷酶是一种含有七个N -链接的的低聚糖链的糖蛋白。是迄今为止唯一解析的晶体结构的糖基化的beta-半乳糖苷酶。
Abstract:
β-Galactosidases catalyze the hydrolysis of β(1-3) and β(1-4) galactosyl bonds in oligosaccharides as well as the inverse reaction of enzymatic condensation and transglycosylation. Here we report the crystallographic structures of …
>>>
β-Galactosidases catalyze the hydrolysis of β(1-3) and β(1-4) galactosyl bonds in oligosaccharides as well as the inverse reaction of enzymatic condensation and transglycosylation. Here we report the crystallographic structures of Penicillium sp. β-galactosidase and its complex with galactose solved by the SIRAS quick cryo-soaking technique at 1.90 Å and 2.10 Å resolution, respectively. The amino acid sequence of this 120 kDa protein was first assigned putatively on the basis of inspection of the experimental electron density maps and then determined by nucleotide sequence analysis. Primary structure alignments reveal that Penicillium sp. β-galactosidase belongs to family 35 of glycosyl hydrolases (GHF-35). This model is the first 3D structure for a member of GHF-35. Five distinct domains which comprise the structure are assembled in a way previously unobserved for β-galactosidases. Superposition of this complex with other β-galactosidase complexes from several hydrolase families allowed the identification of residue Glu200 as the proton donor and residue Glu299 as the nucleophile involved in catalysis. Penicillium sp. β-galactosidase is a glycoprotein containing seven N-linked oligosaccharide chains and is the only structure of a glycosylated β-galactosidase described to date.
<<<
翻译
692.
彬
(2022-11-30 23:31):
#paper doi: 10.3168/jds.2009-2581. Conte G , Mele M , Chessa S , et al. Diacylglycerol acyltransferase 1, stearoyl-CoA desaturase 1, and sterol regulatory element binding protein 1 gene polymorphisms and milk fatty acid composition in Italian Brown cattle[J]. Journal of Dairy Science, 2010, 93(2):753-763. 该研究对意大利褐牛群的SCD1、DGAT1和SREBP1基因进行分型,并研究了这3个基因分型是否与乳中脂肪酸组成相关。结果显示意大利褐牛SCD1、SREBP1和DGAT1这3个基因的基因频率分别为82%、84%和98%,表现出等位基因分布不平衡,SCD1和DGAT1基因多态性与牛奶脂肪酸组分显著相关,而SREBP1基因多态性与牛奶脂肪酸组分关联不显著。
Abstract:
Several lipogenic genes have been shown to have effects on lipid metabolism: stearoyl CoA desaturase 1 (SCD1) catalyzes the desaturation of several fatty acids (FA) in the cis-Delta(9) position in …
>>>
Several lipogenic genes have been shown to have effects on lipid metabolism: stearoyl CoA desaturase 1 (SCD1) catalyzes the desaturation of several fatty acids (FA) in the cis-Delta(9) position in mammary glands of ruminant animals, diacylglycerol acyltransferase 1 (DGAT1) is a key enzyme in triacylglycerol synthesis in the mammary gland, and sterol regulatory element binding protein (SREBP-1) is a transcription factor that regulates expression levels of the SCD1 gene and other genes relevant to lipid and FA metabolism in adipose tissue and mammary gland. In this work, 351 Italian Brown cows were genotyped for polymorphisms in the SCD1, SREBP-1, and DGAT1 genes to reveal the allelic distribution in the population. Subsequently, effects on individual milk FA composition and on cis-9 unsaturated/saturated FA ratios, a proxy of mammary stearoyl CoA desaturase activity, were investigated. The genotypes of SCD1 (A293V) and DGAT1 (K232A) were determined by an approach based on the ligation detection reaction and a universal array, whereas the genotype of SREBP-1 (84-bp insertion-deletion) was revealed by PCR amplification of intron 5. The genotype analysis showed an unbalanced distribution of alleles within all genes, being the allele with higher gene frequency at 82, 84, and 98% for SCD1, SREBP-1, and DGAT1, respectively. Significant associations between SCD1 and DGAT1 polymorphisms and milk FA composition were found, whereas SREBP-1 polymorphism was not associated with milk FA composition. In particular, SCD1 showed significant association with C14:1 cis-9 and C14:1 cis-9/C14:0, which is considered the best proxy of the desaturation activity in mammary gland. The DGAT1 polymorphism had the strongest association with milk FA composition, which confirmed the key role of DGAT1 in lipid metabolism of mammary gland. However, the unbalanced distribution of alleles in all polymorphisms investigated suggested that the size of population should be increased to confirm the results of the present study.
<<<
翻译
693.
Ricardo
(2022-11-30 23:24):
#paper http://dx.doi.org/10.1016/j.neuroimage.2017.07.008 Quicksilver: Fast predictive image registration – A deep learning approach 介绍了一种快速变形图像配准方法——Quicksilver。图像对的配准通过直接基于图像外观的变形模型的patch-wise预测工作。采用深度编码器-解码器网络作为预测模型。虽然预测策略是通用的,但作者主要关注大变形Diffeomorphic Metric Mapping (LDDMM)模型的预测。具体地说,作者预测了LDDMM的动量参数化,这促进了patch-wise预测策略,同时保持了LDDMM的理论性质,如保证微分同胚映射以获得足够强的正则化。作者还提供了预测网络的概率版本,可以在测试期间进行采样,以计算预测变形的不确定性。最后,作者引入了一种新的修正网络,它大大提高了现有预测网络的预测精度。
Abstract:
This paper introduces Quicksilver, a fast deformable image registration method. Quicksilver registration for image-pairs works by patch-wise prediction of a deformation model based directly on image appearance. A deep encoder-decoder …
>>>
This paper introduces Quicksilver, a fast deformable image registration method. Quicksilver registration for image-pairs works by patch-wise prediction of a deformation model based directly on image appearance. A deep encoder-decoder network is used as the prediction model. While the prediction strategy is general, we focus on predictions for the Large Deformation Diffeomorphic Metric Mapping (LDDMM) model. Specifically, we predict the momentum-parameterization of LDDMM, which facilitates a patch-wise prediction strategy while maintaining the theoretical properties of LDDMM, such as guaranteed diffeomorphic mappings for sufficiently strong regularization. We also provide a probabilistic version of our prediction network which can be sampled during the testing time to calculate uncertainties in the predicted deformations. Finally, we introduce a new correction network which greatly increases the prediction accuracy of an already existing prediction network. We show experimental results for uni-modal atlas-to-image as well as uni-/multi-modal image-to-image registrations. These experiments demonstrate that our method accurately predicts registrations obtained by numerical optimization, is very fast, achieves state-of-the-art registration results on four standard validation datasets, and can jointly learn an image similarity measure. Quicksilver is freely available as an open-source software.
<<<
翻译
694.
muton
(2022-11-30 23:19):
#paper https://science.org/doi/10.1126/ sciadv.abm3829 Science Advances,2022,Higher-dimensional neural representations predict better episodic memory
情景记忆使人类能够编码并随后生动地检索有关我们丰富经历的信息,但怎样的神经表征可以支持这一心理能力?作者让被试学习人脸图片和词语的配对,使用表征维度的分析方法,对由脑成像得到的神经相似性矩阵进行PCA分析,得到每个主成分的eigenvalue,通过对eigenvalue的处理得到RD(representational dimensionality)值,来分析面孔选择区和其他相关脑区的差异,结果发现,面孔选择区保留了高维表征,重要的是,RD值越大,记忆效应就越好。本文提供了新的神经表征分析方法。
Abstract:
Episodic memory enables humans to encode and later vividly retrieve information about our rich experiences, yet the neural representations that support this mental capacity are poorly understood. Using a large …
>>>
Episodic memory enables humans to encode and later vividly retrieve information about our rich experiences, yet the neural representations that support this mental capacity are poorly understood. Using a large fMRI dataset ( = 468) of face-name associative memory tasks and principal component analysis to examine neural representational dimensionality (RD), we found that the human brain maintained a high-dimensional representation of faces through hierarchical representation within and beyond the face-selective regions. Critically, greater RD was associated with better subsequent memory performance both within and across participants, and this association was specific to episodic memory but not general cognitive abilities. Furthermore, the frontoparietal activities could suppress the shared low-dimensional fluctuations and reduce the correlations of local neural responses, resulting in greater RD. RD was not associated with the degree of item-specific pattern similarity, and it made complementary contributions to episodic memory. These results provide a mechanistic understanding of the role of RD in supporting accurate episodic memory.
<<<
翻译
695.
张贝
(2022-11-30 22:20):
#paper DOI: 10.1038/s41586-020-1969-6 Nature
. 2020 Feb;578(7793):82-93 Pan-cancer analysis of whole genomes
本文是泛癌全基因组分析(PCAWG)联盟在nature上发表的一篇文章,对ICGC和TCGA的38种常见癌症的2658例肿瘤及其配对正常组织样本的全基因组测序数据进行系统整合分析。癌症基因组平均有4-5个驱动突变(结合编码和非编码基因元件);约有5%的病例未发现驱动突变,表明癌症驱动基因的发现仍未完全;常见和罕见的遗传变异会影响体细胞突变的模式,包括点突变、结构变异和体细胞反转录转座。同时文章描述了非编码突变、识别了导致碱基替换、小片段插入和缺失以及结构变异的突变过程的新特征;分析了肿瘤演化的时机和模式;描述了体细胞突变对剪接、表达水平、融合基因和启动子活性的多种转录结果;并评估了癌症基因组的一系列特征。
Abstract:
Cancer is driven by genetic change, and the advent of massively parallel sequencing has enabled systematic documentation of this variation at the whole-genome scale. Here we report the integrative analysis …
>>>
Cancer is driven by genetic change, and the advent of massively parallel sequencing has enabled systematic documentation of this variation at the whole-genome scale. Here we report the integrative analysis of 2,658 whole-cancer genomes and their matching normal tissues across 38 tumour types from the Pan-Cancer Analysis of Whole Genomes (PCAWG) Consortium of the International Cancer Genome Consortium (ICGC) and The Cancer Genome Atlas (TCGA). We describe the generation of the PCAWG resource, facilitated by international data sharing using compute clouds. On average, cancer genomes contained 4-5 driver mutations when combining coding and non-coding genomic elements; however, in around 5% of cases no drivers were identified, suggesting that cancer driver discovery is not yet complete. Chromothripsis, in which many clustered structural variants arise in a single catastrophic event, is frequently an early event in tumour evolution; in acral melanoma, for example, these events precede most somatic point mutations and affect several cancer-associated genes simultaneously. Cancers with abnormal telomere maintenance often originate from tissues with low replicative activity and show several mechanisms of preventing telomere attrition to critical levels. Common and rare germline variants affect patterns of somatic mutation, including point mutations, structural variants and somatic retrotransposition. A collection of papers from the PCAWG Consortium describes non-coding mutations that drive cancer beyond those in the TERT promoter; identifies new signatures of mutational processes that cause base substitutions, small insertions and deletions and structural variation; analyses timings and patterns of tumour evolution; describes the diverse transcriptional consequences of somatic mutation on splicing, expression levels, fusion genes and promoter activity; and evaluates a range of more-specialized features of cancer genomes.
<<<
翻译
696.
周周复始
(2022-11-30 21:53):
#paper https://doi.org/10.1007/978-3-031-17117-8_4 Chen, L., Wu, J., Wu, Q., Wei, H., Zhang, Y. (2022). Continuous Longitudinal Fetus Brain Atlas Construction via Implicit Neural Representation. In: Licandro, R., Melbourne, A., Abaci Turk, E., Macgowan, C., Hutter, J. (eds) Perinatal, Preterm and Paediatric Image Analysis. PIPPI 2022. Lecture Notes in Computer Science, vol 13575. Springer, Cham. 纵向胎儿脑图谱是了解和表示胎儿大脑复杂发育过程的工具。现有的胎儿脑图谱的创建通常是平均每个时间的脑模版,时间点也是离散的。但由于样本在不同时间点的个体遗传趋势不同,所得到的图谱存在时间上的不一致性,可能导致大脑发育特征参数在时间轴上出现误差。因此本文提出了一个多阶段深度学习框架来解决时间不一致性的问题,将时间不一致性问题转换为4D图像数据去噪任务。利用隐式神经表示,创建了连续无噪声的胎儿纵向脑图谱,并将其作为4D时空坐标函数。并用两个公开的胎儿大脑图谱(CRL和FBA-Chinese图谱)做实验。结果表明,该方法在保留胎儿大脑结构表示的同时,显著提高了图谱的时间一致性。此外,连续的胎儿纵向脑图谱可广泛应用于生成更精细的4D时空分辨率图谱。
Abstract:
Longitudinal fetal brain atlas is a powerful tool for understanding and characterizing the complex process of fetus brain development. Existing fetus brain atlases are typically constructed by averaged brain images …
>>>
Longitudinal fetal brain atlas is a powerful tool for understanding and characterizing the complex process of fetus brain development. Existing fetus brain atlases are typically constructed by averaged brain images on discrete time points independently over time. Due to the differences in onto-genetic trends among samples at different time points, the resulting atlases suffer from temporal inconsistency, which may lead to estimating error of the brain developmental characteristic parameters along the timeline. To this end, we proposed a multi-stage deep-learning framework to tackle the time inconsistency issue as a 4D (3D brain volume + 1D age) image data denoising task. Using implicit neural representation, we construct a continuous and noise-free longitudinal fetus brain atlas as a function of the 4D spatial-temporal coordinate. Experimental results on two public fetal brain atlases (CRL and FBA-Chinese atlases) show that the proposed method can significantly improve the atlas temporal consistency while maintaining good fetus brain structure representation. In addition, the continuous longitudinal fetus brain atlases can also be extensively applied to generate finer 4D atlases in both spatial and temporal resolution.
<<<
翻译
697.
林海onrush
(2022-11-30 21:51):
#paper,https://doi.org/10.48550/arXiv.2211.16197,FJMP: Factorized Joint Multi-Agent Motion Prediction over Learned Directed Acyclic Interaction Graphs,该研究针对自动驾驶轨迹预测生成问题,提出了FJMP,一种学习有向无环相互作用图的因子分解多智能体联合运动预测框架.使用未来场景交互动力学作为稀疏有向交互图,边缘表示agent之间的显式交互,修剪图成有向无环图(DAG)并分解联合预测任务,根据 DAG 的部分排序,其中联合未来轨迹使用有向无环图神经网络DAGNN。在INTERACTION和Argoverse2数据集上,证明了FJMP与非因子化相比能得到准确且场景一致的联合轨迹预测。FJMP在交互的多智能体INTERACTION基准测试上取得SOTA。
arXiv,
2022.
DOI: 10.48550/arXiv.2211.16197
Abstract:
Predicting the future motion of road agents is a critical task in an autonomous driving pipeline. In this work, we address the problem of generating a set of scene-level, or …
>>>
Predicting the future motion of road agents is a critical task in an autonomous driving pipeline. In this work, we address the problem of generating a set of scene-level, or joint, future trajectory predictions in multi-agent driving scenarios. To this end, we propose FJMP, a Factorized Joint Motion Prediction framework for multi-agent interactive driving scenarios. FJMP models the future scene interaction dynamics as a sparse directed interaction graph, where edges denote explicit interactions between agents. We then prune the graph into a directed acyclic graph (DAG) and decompose the joint prediction task into a sequence of marginal and conditional predictions according to the partial ordering of the DAG, where joint future trajectories are decoded using a directed acyclic graph neural network (DAGNN). We conduct experiments on the INTERACTION and Argoverse 2 datasets and demonstrate that FJMP produces more accurate and scene-consistent joint trajectory predictions than non-factorized approaches, especially on the most interactive and kinematically interesting agents. FJMP ranks 1st on the multi-agent test leaderboard of the INTERACTION dataset.
<<<
翻译
698.
魏魏魏
(2022-11-30 21:50):
#paper doi:10.1111/cdep.12279 Child Development Perspectives, (2018), The Development of Self and Identity in Adolescence: Neural Evidence and Implications for a Value-Based Choice Perspective on Motivated Behavior.
青少年的自我意识和自我同一性发展是重要发展任务,这将影响他们的自主性和社会关系。与自我过程相关的神经影像学研究发现在青少年阶段与自我同一性关系密切的腹侧前额叶皮层的活动更多,这意味着青少年基于价值观和动机的行为及决策会出现进步。在本文中,作者提出了青少年基于动机的行为会受到基于价值观的决策过程的影响的观点,而基于价值观的决策过程以腹侧前额叶皮层为中心。作者的观点形成了一个独特的青少年神经发育模型,这一模型聚焦奖励的敏感性和认知控制,同时认为青少年发展中的自我和自我同一性会产生重要的作用。本文中作者重点阐述了这一模型和青少年自我发展的关系,为青少年自我和行为研究提供了新的思路。
Abstract:
Following a key developmental task of childhood-building a foundation of self-knowledge in the form of domain-specific self-concepts-adolescents begin to explore their emerging identities in ways that foster autonomy and connectedness. …
>>>
Following a key developmental task of childhood-building a foundation of self-knowledge in the form of domain-specific self-concepts-adolescents begin to explore their emerging identities in ways that foster autonomy and connectedness. Neuroimaging studies of self-related processes demonstrate enhanced engagement of the ventromedial prefrontal cortex in adolescence, which may facilitate and reflect the development of identity by integrating the value of potential actions and choices. Drawing from neuroeconomic and social cognitive accounts, we propose that motivated behavior during adolescence can be modeled by a general value-based decision-making process centered around value accumulation in the ventromedial prefrontal cortex. This approach advances models of adolescent neurodevelopment that focus on reward sensitivity and cognitive control by considering more diverse value inputs, including contributions of developing self- and identity-related processes. It also considers adolescent decision making and behavior from adolescents' point of view rather than adults' perspectives on what adolescents should value or how they should behave.
<<<
翻译
699.
王昊
(2022-11-30 19:37):
#paper https://cis.temple.edu/tagit/presentations/A%20Path%20Towards%20Autonomous%20Machine%20Intelligence.pdf. A Path Towards Autonomous Machine Intelligence. LeCun. A Path Towards Autonomous Machine Intelligence Version 0.9.2, 2022-06-27. 62. Yann LeCun指明下一代AI方向:自主机器智能。 LeCun在本文中提出了一套认知的架构,以及训练其中world model的方法。主要包括以下模块: (1)配置器(Configurator)模块负责执行控制(executive control):给定要执行的任务,可以通过调整这些模块的参数来预先配置感知模块(perception module)、世界模型(world model)、成本(cost)和当前任务的 actor。(2)感知模块(Perception module)接收来自传感器的信号并估计当前世界的状态,对于给定的任务,只有一小部分感知到的世界状态是相关和有用的。配置器模块启动感知系统,从感知中提取相关信息,完成手头的任务。(3)世界模型(World model)的作用是双重的:(1)估计感知未提供的关于世界状态的缺失信息;(2)预测合理的未来世界状态。(4)成本模块(Cost module)计算单个标量的输出,该输出预测智能体的不适(discomfort)程度。(5)Actor 模块计算动作序列的提议。(6)短期记忆模块(Short-term memory module)跟踪当前和预测的世界状态以及相关成本。
2022.
Abstract:
How could machines learn as efficiently as humans and animals? How could machines learn to reason and plan? How could machines learn representations of percepts and action plans at multiple …
>>>
How could machines learn as efficiently as humans and animals? How could machines learn to reason and plan? How could machines learn representations of percepts and action plans at multiple levels of abstraction, enabling them to reason, predict, and plan at multiple time horizons? This position paper proposes an architecture and training paradigms with which to construct autonomous intelligent agents. It combines concepts such as configurable predictive world model, behavior driven through intrinsic motivation, and hierarchical joint embedding architectures trained with self-supervised learning.
<<<
翻译
700.
哪有情可长
(2022-11-30 19:24):
#paper THP9 enhances seed protein content and nitrogen-use efficiency in maize, Nature 2022 October, https://doi.org/10.1038/s41586-022-05441-2. 鉴定未驯化的野生型玉米大刍草的蛋白发现其要比现代玉米籽粒蛋白含量高,由于玉米大刍草的基因型复杂,其参考基因组一直没有被组装,作者通过构建已知参考基因组B73和大刍草杂交后代,测定后代基因型去掉已知的参考基因组B73进行组装大刍草的参考基因组,将两套参考基因组进行共线性分析发现存在大量的结构变异,推测蛋白含量的高低可能是由于结构变异引起。作者们继续构建群体,通过BSA鉴定到了控制籽粒蛋白含量的基因THP9,该基因在现代品种中存在48bp的缺失,导致剪切位点发生变化后导致基因翻译提前终止,最终导致现代玉米籽粒蛋白含量降低。作者又利用525份自然群体进行GWAS分析,也鉴定到该基因所处的区间。对525份材料按照基因型可以分成三种单倍型,Hap1跟野生型基因型一致,作者又通过转基因验证该基因的确能够提高蛋白含量,又通过构建NIL群体,继续验证该基因的功能,发现当籽粒蛋白含量高时,根部的氮吸收效率高,该基因也是首次在玉米中鉴定的第一个高蛋白基因。
Abstract:
Teosinte, the wild ancestor of maize (Zea mays subsp. mays), has three times the seed protein content of most modern inbreds and hybrids, but the mechanisms that are responsible for …
>>>
Teosinte, the wild ancestor of maize (Zea mays subsp. mays), has three times the seed protein content of most modern inbreds and hybrids, but the mechanisms that are responsible for this trait are unknown. Here we use trio binning to create a contiguous haplotype DNA sequence of a teosinte (Zea mays subsp. parviglumis) and, through map-based cloning, identify a major high-protein quantitative trait locus, TEOSINTE HIGH PROTEIN 9 (THP9), on chromosome 9. THP9 encodes an asparagine synthetase 4 enzyme that is highly expressed in teosinte, but not in the B73 inbred, in which a deletion in the tenth intron of THP9-B73 causes incorrect splicing of THP9-B73 transcripts. Transgenic expression of THP9-teosinte in B73 significantly increased the seed protein content. Introgression of THP9-teosinte into modern maize inbreds and hybrids greatly enhanced the accumulation of free amino acids, especially asparagine, throughout the plant, and increased seed protein content without affecting yield. THP9-teosinte seems to increase nitrogen-use efficiency, which is important for promoting a high yield under low-nitrogen conditions.
<<<
翻译