Scrambled and not-so-tiny genomes of fungal endosymbionts [Microbiology]

炒的和不那么微小的真菌共生微生物基因组[ ]

Symbiosis, defined as prolonged and close association of two or more different organisms, is a major driving force for expansion of biological diversity from genes to ecosystems. In the most intimate form, the symbiont lives inside the cells of its host, is heritable, and the two parties could no longer...

[详细]

  • PNAS
  • 5年前
  • Commentaries

Generic, phenomenological, on-the-fly renormalized repulsion model for self-limited organization of terminal supraparticle assemblies [Engineering]

一般的,现象学,对飞重整化排斥模型为终端超微粒组件[工程]自限性组织

Self-limited, or terminal, supraparticles have long received great interest because of their abundance in biological systems (DNA bundles and virus capsids) and their potential use in a host of applications ranging from photonics and catalysis to encapsulation for drug delivery. Moreover, soft, uniform colloidal aggregates are a promising candidate for...

[详细]

  • PNAS
  • 5年前
  • PNAS Plus

Regulation by a chaperone improves substrate selectivity during cotranslational protein targeting [Biochemistry]

一个伴侣调控提高底物选择性翻译的蛋白靶向[生化]中

The ribosome exit site is a crowded environment where numerous factors contact nascent polypeptides to influence their folding, localization, and quality control. Timely and accurate selection of nascent polypeptides into the correct pathway is essential for proper protein biogenesis. To understand how this is accomplished, we probe the mechanism by...

[详细]

  • PNAS
  • 5年前
  • PNAS Plus

Conserved SMP domains of the ERMES complex bind phospholipids and mediate tether assembly [Biochemistry]

保守的SMP结构域介导的ERMES复杂的磷脂结合的系绳组件[生化]

Membrane contact sites (MCS) between organelles are proposed as nexuses for the exchange of lipids, small molecules, and other signals crucial to cellular function and homeostasis. Various protein complexes, such as the endoplasmic reticulum-mitochondrial encounter structure (ERMES), function as dynamic molecular tethers between organelles. Here, we report the reconstitution and...

[详细]

  • PNAS
  • 5年前
  • PNAS Plus

Conformational processing of oncogenic v-Src kinase by the molecular chaperone Hsp90 [Biochemistry]

癌基因v-src激酶的分子伴侣Hsp90的[生化]构象的处理

Hsp90 is a molecular chaperone involved in the activation of numerous client proteins, including many kinases. The most stringent kinase client is the oncogenic kinase v-Src. To elucidate how Hsp90 chaperones kinases, we reconstituted v-Src kinase chaperoning in vitro and show that its activation is ATP-dependent, with the cochaperone Cdc37...

[详细]

  • PNAS
  • 5年前
  • PNAS Plus

Contingency and entrenchment in protein evolution under purifying selection [Evolution]

在净化选择[进化]在蛋白质进化的应急和防御

The phenotypic effect of an allele at one genetic site may depend on alleles at other sites, a phenomenon known as epistasis. Epistasis can profoundly influence the process of evolution in populations and shape the patterns of protein divergence across species. Whereas epistasis between adaptive substitutions has been studied extensively,...

[详细]

  • PNAS
  • 5年前
  • PNAS Plus

Extracellular ATP induces the rapid release of HIV-1 from virus containing compartments of human macrophages [Microbiology]

细胞外ATP诱导HIV-1的快速释放含人巨噬细胞病毒微生物室[ ]

HIV type 1 (HIV-1) infects CD4+ T lymphocytes and tissue macrophages. Infected macrophages differ from T cells in terms of decreased to absent cytopathicity and for active accumulation of new progeny HIV-1 virions in virus-containing compartments (VCC). For these reasons, infected macrophages are believed to act as “Trojan horses” carrying...

[详细]

  • PNAS
  • 5年前
  • PNAS Plus

Protein synthesis during cellular quiescence is inhibited by phosphorylation of a translational elongation factor [Microbiology]

在细胞静止期蛋白质的合成是通过一个翻译延伸因子[微生物]磷酸化的抑制

In nature, most organisms experience conditions that are suboptimal for growth. To survive, cells must fine-tune energy-demanding metabolic processes in response to nutrient availability. Here, we describe a novel mechanism by which protein synthesis in starved cells is down-regulated by phosphorylation of the universally conserved elongation factor Tu (EF-Tu). Phosphorylation...

[详细]

  • PNAS
  • 5年前
  • PNAS Plus

Bioimage analysis of Shigella infection reveals targeting of colonic crypts [Microbiology]

志贺菌属感染的图像分析显示结肠隐窝的微生物学] [目标

Few studies within the pathogenic field have used advanced imaging and analytical tools to quantitatively measure pathogenicity in vivo. In this work, we present a novel approach for the investigation of host–pathogen processes based on medium-throughput 3D fluorescence imaging. The guinea pig model for Shigella flexneri invasion of the colonic...

[详细]

  • PNAS
  • 5年前
  • PNAS Plus

Single-molecule analysis reveals widespread structural variation in multiple myeloma [Applied Biological Sciences]

单分子分析显示在多发性骨髓瘤广泛的结构性变化[应用生物科学]

Multiple myeloma (MM), a malignancy of plasma cells, is characterized by widespread genomic heterogeneity and, consequently, differences in disease progression and drug response. Although recent large-scale sequencing studies have greatly improved our understanding of MM genomes, our knowledge about genomic structural variation in MM is attenuated due to the limitations...

[详细]

  • PNAS
  • 5年前
  • Biological Sciences

Structural basis of a Ni acquisition cycle for [NiFe] hydrogenase by Ni-metallochaperone HypA and its enhancer [Biochemistry]

一个[镍铁]氢化镍metallochaperone HYPA及其增强子[生化] NI采集周期结构基础

The Ni atom at the catalytic center of [NiFe] hydrogenases is incorporated by a Ni-metallochaperone, HypA, and a GTPase/ATPase, HypB. We report the crystal structures of the transient complex formed between HypA and ATPase-type HypB (HypBAT) with Ni ions. Transient association between HypA and HypBAT is controlled by the ATP...

[详细]

  • PNAS
  • 5年前
  • Biological Sciences

Retro-translocation of mitochondrial intermembrane space proteins [Biochemistry]

线粒体膜间隙蛋白[生化]复古易位

The content of mitochondrial proteome is maintained through two highly dynamic processes, the influx of newly synthesized proteins from the cytosol and the protein degradation. Mitochondrial proteins are targeted to the intermembrane space by the mitochondrial intermembrane space assembly pathway that couples their import and oxidative folding. The folding trap...

[详细]

  • PNAS
  • 5年前
  • Biological Sciences

Empirical inference of circuitry and plasticity in a kinase signaling network [Biochemistry]

在一个激酶信号转导网络[生化]电路与可塑性实证推理

Our understanding of physiology and disease is hampered by the difficulty of measuring the circuitry and plasticity of signaling networks that regulate cell biology, and how these relate to phenotypes. Here, using mass spectrometry-based phosphoproteomics, we systematically characterized the topology of a network comprising the PI3K/Akt/mTOR and MEK/ERK signaling axes...

[详细]

  • PNAS
  • 5年前
  • Biological Sciences

Molecular diffusion in the human nail measured by stimulated Raman scattering microscopy [Biophysics and Computational Biology]

在受激散射显微镜[与计算生物]拉曼测量人类钉分子扩散

The effective treatment of diseases of the nail remains an important unmet medical need, primarily because of poor drug delivery. To address this challenge, the diffusion, in real time, of topically applied chemicals into the human nail has been visualized and characterized using stimulated Raman scattering (SRS) microscopy. Deuterated water...

[详细]

  • PNAS
  • 5年前
  • Biological Sciences

Inference of transcriptional regulation in cancers [Biophysics and Computational Biology]

在癌症的[与计算生物]转录调控的推理

Despite the rapid accumulation of tumor-profiling data and transcription factor (TF) ChIP-seq profiles, efforts integrating TF binding with the tumor-profiling data to understand how TFs regulate tumor gene expression are still limited. To systematically search for cancer-associated TFs, we comprehensively integrated 686 ENCODE ChIP-seq profiles representing 150 TFs with 7484...

[详细]

  • PNAS
  • 5年前
  • Biological Sciences

Gate-controlled proton diffusion and protonation-induced ratchet motion in the stator of the bacterial flagellar motor [Biophysics and Computational Biology]

门控质子和质子引起的棘轮运动的细菌鞭毛马达[与计算生物]定子

The proton permeation process of the stator complex MotA/B in the flagellar motor of Escherichia coli was investigated. The atomic model structure of the transmembrane part of MotA/B was constructed based on the previously published disulfide cross-linking and tryptophan scanning mutations. The dynamic permeation of hydronium/sodium ions and water molecule...

[详细]

  • PNAS
  • 5年前
  • Biological Sciences

Identification of a triplet pair intermediate in singlet exciton fission in solution [Chemistry]

在单线态激子裂变溶液[化学]三对中级鉴定

Singlet exciton fission is the spin-conserving transformation of one spin-singlet exciton into two spin-triplet excitons. This exciton multiplication mechanism offers an attractive route to solar cells that circumvent the single-junction Shockley–Queisser limit. Most theoretical descriptions of singlet fission invoke an intermediate state of a pair of spin-triplet excitons coupled into...

[详细]

  • PNAS
  • 5年前
  • Physical Sciences

Long-circulating siRNA nanoparticles for validating Prohibitin1-targeted non-small cell lung cancer treatment [Engineering]

长循环纳米粒靶向siRNA验证Prohibitn1治疗非小细胞肺癌[工程]

RNA interference (RNAi) represents a promising strategy for identification and validation of putative therapeutic targets and for treatment of a myriad of important human diseases including cancer. However, the effective systemic in vivo delivery of small interfering RNA (siRNA) to tumors remains a formidable challenge. Using a robust self-assembly strategy,...

[详细]

  • PNAS
  • 5年前
  • Biological Sciences

Fundamental limits on the accuracy of demographic inference based on the sample frequency spectrum [Evolution]

基本上基于样本的频谱[进化]的人口统计推断的精度限制

The sample frequency spectrum (SFS) of DNA sequences from a collection of individuals is a summary statistic that is commonly used for parametric inference in population genetics. Despite the popularity of SFS-based inference methods, little is currently known about the information theoretic limit on the estimation accuracy as a function...

[详细]

  • PNAS
  • 5年前
  • Physical Sciences

Mosaic genome of endobacteria in arbuscular mycorrhizal fungi: Transkingdom gene transfer in an ancient mycoplasma-fungus association [Microbiology]

在丛枝菌根内生细菌基因组:镶嵌在一个古老的支原体菌协会[生物学] TransKingdom基因转移

For more than 450 million years, arbuscular mycorrhizal fungi (AMF) have formed intimate, mutualistic symbioses with the vast majority of land plants and are major drivers in almost all terrestrial ecosystems. The obligate plant-symbiotic AMF host additional symbionts, so-called Mollicutes-related endobacteria (MRE). To uncover putative functional roles of these widespread...

[详细]

  • PNAS
  • 5年前
  • Biological Sciences

Minimal genomes of mycoplasma-related endobacteria are plastic and contain host-derived genes for sustained life within Glomeromycota [Microbiology]

支原体相关的内生细菌最小的基因组是塑料和含有宿主基因持续生活在[ ]的专性微生物

Arbuscular mycorrhizal fungi (AMF, Glomeromycota) colonize roots of the majority of terrestrial plants. They provide essential minerals to their plant hosts and receive photosynthates in return. All major lineages of AMF harbor endobacteria classified as Mollicutes, and known as mycoplasma-related endobacteria (MRE). Except for their substantial intrahost genetic diversity and...

[详细]

  • PNAS
  • 5年前
  • Biological Sciences

RNASEK is required for internalization of diverse acid-dependent viruses [Microbiology]

rnasek是多种酸依赖病毒[微生物]的内在要求

Viruses must gain entry into cells to establish infection. In general, viruses enter either at the plasma membrane or from intracellular endosomal compartments. Viruses that use endosomal pathways are dependent on the cellular factors that control this process; however, these genes have proven to be essential for endogenous cargo uptake,...

[详细]

  • PNAS
  • 5年前
  • Biological Sciences

Host lysozyme-mediated lysis of Lactococcus lactis facilitates delivery of colitis-attenuating superoxide dismutase to inflamed colons [Microbiology]

溶菌酶乳酸乳球菌宿主介导的溶解有利于减轻发炎结肠结肠炎超氧化物歧化酶[微生物]交货

Beneficial microbes that target molecules and pathways, such as oxidative stress, which can negatively affect both host and microbiota, may hold promise as an inflammatory bowel disease therapy. Prior work showed that a five-strain fermented milk product (FMP) improved colitis in T-bet−/− Rag2−/− mice. By varying the number of strains...

[详细]

  • PNAS
  • 5年前
  • Biological Sciences