bluuebunny/crossref_metadata_2025 huggingface dataset:
Drinking water microbiome assembly induced by water stagnation
Authors: Ling Fangqiong , Whitaker Rachel , LeChevallier Mark W , Liu Wen-Tso
Published: April 2018

What happens to tap water when you are away from home? Day-to-day water stagnation in building plumbing can potentially result in water quality deterioration (e.g., lead release or pathogen proliferation), which is a major public health concern. However, little is known about the microbial ecosystem processes in plumbing systems, hindering the development of biological monitoring strategies. Here, we track tap water microbiome assembly in situ, showing that bacterial community composition changes rapidly from the city supply following ~6-day stagnation, along with an increase in cell count from 103 cells/mL to upwards of 7.8 × 105 cells/mL. Remarkably, bacterial community assembly was highly reproducible in this built environment system (median Spearman correlation between temporal replicates = 0.78). Using an island biogeography model, we show that neutral processes arising from the microbial communities in the city water supply (i.e., migration and demographic stochasticity) explained the island community composition in proximal pipes (Goodness-of-fit = 0.48), yet declined as water approached the faucet (Goodness-of-fit = 0.21). We developed a size-effect model to simulate this process, which indicated that pipe diameter drove these changes by mediating the kinetics of hypochlorite decay and cell detachment, affecting selection, migration, and demographic stochasticity. Our study challenges current water quality monitoring practice worldwide which ignore biological growth in plumbing, and suggests the island biogeography model as a useful framework to evaluate building water system quality.
Aberrant salience network functional connectivity in auditory verbal hallucinations: a first episode psychosis sample
Authors: Mallikarjun Pavan Kumar , Lalousis Paris Alexandros , Dunne Thomas Frederick , Heinze Kareen , Reniers Renate LEP , Broome Matthew R. , Farmah Baldeep , Oyebode Femi , Wood Stephen J , Upthegrove Rachel
Published: April 2018

Auditory verbal hallucinations (AVH) often lead to distress and functional disability, and are frequently associated with psychotic illness. Previously both state and trait magnetic resonance imaging (MRI) studies of AVH have identified activity in brain regions involving auditory processing, language, memory and areas of default mode network (DMN) and salience network (SN). Current evidence is clouded by research mainly in participants on long-term medication, with chronic illness and by choice of seed regions made ‘a priori’. Thus, the aim of this study was to elucidate the intrinsic functional connectivity in patients presenting with first episode psychosis (FEP). Resting state functional MRI data were available from 18 FEP patients, 9 of whom also experienced AVH of sufficient duration in the scanner and had symptom capture functional MRI (sc fMRI), together with 18 healthy controls. Symptom capture results were used to accurately identify specific brain regions active during AVH; including the superior temporal cortex, insula, precuneus, posterior cingulate and parahippocampal complex. Using these as seed regions, patients with FEP and AVH showed increased resting sb-FC between parts of the SN and the DMN and between the SN and the cerebellum, but reduced sb-FC between the claustrum and the insula, compared to healthy controls.It is possible that aberrant activity within the DMN and SN complex may be directly linked to impaired salience appraisal of internal activity and AVH generation. Furthermore, decreased intrinsic functional connectivity between the claustrum and the insula may lead to compensatory over activity in parts of the auditory network including areas involved in DMN, auditory processing, language and memory, potentially related to the complex and individual content of AVH when they occur.
Effects on gene expression and behavior of untagged short tandem repeats: the case of arginine vasopressin receptor 1a (AVPR1a) and externalizing behaviors
Authors: Landefeld Clare C , Hodgkinson Colin A , Spagnolo Primavera A , Marietta Cheryl A , Shen Pei-Hong , Sun Hui , Zhou Zhifeng , Lipska Barbara K , Goldman David
Published: April 2018

Genome-wide association studies (GWAS) of complex, heritable, behavioral phenotypes have yielded an incomplete accounting of the genetic influences. The identified loci explain only a portion of the observed heritability, and few of the loci have been shown to be functional. It is clear that current GWAS techniques overlook key components of phenotypically relevant genetic variation, either because of sample size, as is frequently asserted, or because of methodology. Here we use arginine vasopressin receptor 1a (AVPR1a) as an in-depth model of a methodologic limitation of GWAS: the functional genetic variation (in the form of short tandem repeats) of this key gene involved in affiliative behavior cannot be captured by current GWAS methodologies. Importantly, we find evidence of differential allele expression, twofold or more, in at least a third of human brain samples heterozygous for a reporter SNP in the AVPR1a transcript. We also show that this functional effect and a downstream phenotype, externalizing behavior, are predicted by AVPR1a STRs but not SNPs.
Enhanced cortical bone expansion in Lgals3-deficient mice during aging
Authors: Maupin Kevin A. , Weaver Kevin , Bergsma Alexis , Christie Cheryl , Zhong Zhendong A. , Yang Tao , Williams Bart O.
Published: April 2018

Imbalances between bone formation and bone resorption, which can occur due to aging or sex hormone deprivation, result in decreased bone mass and an increased risk of fracture. Previous studies have suggested that the β-galactoside binding lectin, galectin-3, is involved in bone remodeling. We compared bone parameters of mice having null alleles of the galectin-3 gene (Lgals3-KO) with those of their wild-type littermates.Lgals3deficiency increased cortical bone expansion at 36 weeks (wk) and preserved or enhanced bone mass in both male and female mutant mice. In addition, femaleLgals3-KO mice were protected from age-related loss of trabecular bone. Histomorphometry and ex vivo primary cell differentiation assays showed increased osteoblastogenesis with little-to-no effect on osteoclastogenesis, suggesting the increased bone mass phenotype is primarily due to increased anabolism. Our study identifies galectin-3 as a negative regulator of bone formation and suggests that disruption of galectin-3 may be useful in preventing bone loss during aging.
PFKFB3 blockade inhibits hepatocellular carcinoma growth by impairing DNA repair through AKT
Authors: Shi Wen-Kai , Zhu Xiao-Dong , Wang Cheng-Hao , Zhang Yuan-Yuan , Cai Hao , Li Xiao-Long , Cao Man-Qing , Zhang Shi-Zhe , Li Kang-Shuai , Sun Hui-Chuan
Published: April 2018

Overexpression of 6-phosphofructo-2-kinase/fructose-2,6-biphosphatase 3 (PFKFB3), a key molecule of glucose metabolism in cytoplasm, has been found in various tumors. Emerging evidence has suggested that PFKFB3 is also located in the nucleus and apparent in regulatory functions other than glycolysis. In this study, we found that PFKFB3 expression is associated with hepatocellular carcinoma (HCC) growth and located mainly in the nucleus of tumor cells. PFKFB3 overexpression was associated with large tumor size (p = 0.04) and poor survival of patients with HCC (p = 0.027). Knockdown of PFKFB3 inhibited HCC growth, not only by reducing glucose consumption but also by damaging the DNA repair function, leading to G2/M phase arrest and apoptosis. In animal studies, overexpression of PFKFB3 is associated with increased tumor growth. Mechanistically, PFKFB3 silencing decreased AKT phosphorylation and reduced the expression of ERCC1, which is an important DNA repair protein. Moreover, PFK15, a selective PFKFB3 inhibitor, significantly inhibited tumor growth in a xenograft model of human HCC. PFKFB3 is a potential novel target in the treatment of HCC.
Fbxw11 promotes the proliferation of lymphocytic leukemia cells through the concomitant activation of NF-κB and β-catenin/TCF signaling pathways
Authors: Wang Lina , Feng Wenli , Yang Xiao , Yang Feifei , Wang Rong , Ren Qian , Zhu Xiaofan , Zheng Guoguang
Published: April 2018

The ubiquitin–proteasome system (UPS) participates in both physiological and pathological processes through the posttranslational regulation of intracellular signal transduction pathways. F-box and WD-40 domain protein 11 (Fbxw11) is a component of the SCF (Skp1–Cul1–F-box) E3 ubiquitin ligase complex. Fbxw11 regulates various signal transduction pathways, and it may have pathological roles in tumorigenesis. However, the role of Fbxw11 in the development of leukemia and the underlying mechanisms remain largely unknown. In this study, Fbxw11 expression was aberrantly upregulated in patients with lymphocytic leukemia. Its expression was dramatically decreased in patients who achieved complete remission (CR) after chemotherapy. The high level of Fbxw11 expression in L1210 lymphocytic leukemia cells stimulated cell proliferation in vitro and tumor formation in vivo. The effects were mediated by the stimulation of cell cycle progression rather than the induction of apoptosis. Furthermore, a bioinformatics analysis suggested concomitant activation of the NF-κB and β-catenin/TCF signaling pathways, which were confirmed by reporter gene assays. Moreover, blocking experiments suggested the involvement of both pathways in the growth-promoting effects of Fbxw11. Our results reveal the role of Fbxw11 in lymphocytic leukemia cells and imply that Fbxw11 may serve as a potential molecular target for the treatment of lymphocytic leukemia.
Nuclear galectin-1-FOXP3 interaction dampens the tumor-suppressive properties of FOXP3 in breast cancer
Authors: Gao Yuan , Li Xiaoju , Shu Zhen , Zhang Kuo , Xue Xiaochang , Li Weina , Hao Qiang , Wang Zhaowei , Zhang Wangqian , Wang Shuning , Zeng Cheng , Fan Dong , Zhang Wei , Zhang Yingqi , Zhao Huadong , Li Meng , Zhang Cun
Published: April 2018

FOXP3 is an important X-linked suppressor of breast cancer. It is reported that FOXP3 is usually mutant, absent, or cytoplasmic distribution in breast cancer cells, which increases the risk of breast cancer. However, in our study the full-length FOXP3 transcript can be detected in breast cancer cells and nuclear FOXP3 is expressed in some breast cancer samples. Therefore, an important question is how the tumor-suppressive function of wild-type FOXP3 is negated in these cancers. We found that Gal-1 is a novel interacting protein of FOXP3 in breast cancer. Furthermore, our results show that the FKH domain in FOXP3 is essential for its interaction with Gal-1. Through ChIP-seq assay, we found that the expression of Gal-1 could inhibit a variety of target genes which were directly regulated by FOXP3. More importantly, these FOXP3-bound genes are involved in the development and metastasis of cancer. Furthermore, functional studies revealed that blocking the FOXP3/Gal-1 interaction restores the tumor-suppressive properties of FOXP3 in breast cancer cells. Finally, we observed that the nuclear abundance of Gal-1 was significantly higher in breast cancer tissues than that in adjacent normal tissues. In addition, we identified that the acidic extracellular microenvironment in breast cancer tissues causes Gal-1 to accumulate in the nucleus. Altogether, nuclear Gal-1 interferes with the binding of FOXP3 to DNA by interacting with the FKH domain of FOXP3, and it indicates a possible mechanism for the loss of the tumor-suppressive properties of FOXP3 in wild-type FOXP3-positive breast cancer.
Taurine protects dopaminergic neurons in a mouse Parkinson’s disease model through inhibition of microglial M1 polarization
Authors: Che Yuning , Hou Liyan , Sun Fuqiang , Zhang Cong , Liu Xiaofang , Piao Fengyuan , Zhang Dan , Li Huihua , Wang Qingshan
Published: April 2018

Microglia-mediated neuroinflammation is implicated in multiple neurodegenerative disorders, including Parkinson’s disease (PD). Hence, the modulatioein of sustained microglial activation may have therapeutic potential. This study is designed to test the neuroprotective efficacy of taurine, a major intracellular free β-amino acid in mammalian tissues, by using paraquat and maneb-induced PD model. Results showed that mice intoxicated with paraquat and maneb displayed progressive dopaminergic neurodegeneration and motor deficits, which was significantly ameliorated by taurine. Taurine also attenuated the aggregation of α-synuclein in paraquat and maneb-intoxicated mice. Mechanistically, taurine suppressed paraquat and maneb-induced microglial activation. Moreover, depletion of microglia abrogated the dopaminergic neuroprotective effects of taurine, revealing the role of microglial activation in taurine-afforded neuroprotection. Subsequently, we found that taurine suppressed paraquat and maneb-induced microglial M1 polarization and gene expression levels of proinflammatory factors. Furthermore, taurine was shown to be able to inhibit the activation of NADPH oxidase (NOX2) by interfering with membrane translocation of cytosolic subunit, p47phox and nuclear factor-kappa B (NF-κB) pathway, two key factors for the initiation and maintenance of M1 microglial inflammatory response. Altogether, our results showed that taurine exerted dopaminergic neuroprotection through inactivation of microglia-mediated neuroinflammation, providing a promising avenue and candidate for the potential therapy for patients suffering from PD.
Macrophage inducible nitric oxide synthase circulates inflammation and promotes lung carcinogenesis
Authors: Wang Xin , Gray Zane , Willette-Brown Jami , Zhu Feng , Shi Gongping , Jiang Qun , Song Na-Young , Dong Liang , Hu Yinling
Published: April 2018

Human lung squamous cell carcinoma (SCC) is highly associated with increased pulmonary macrophage infiltration. Previously, we showed that marked pulmonary infiltrating macrophages were required for spontaneous lung SCC development in a mouse model (L-Ikkα
KA/KA
, KA/KA) that resembles human lung SCC. Interestingly the lung SCC-associated macrophages specifically express elevated inducible nitric oxide synthase (NOS2). However, the role of macrophage NOS2 in lung carcinogenesis has not been explored. Here, we show that NOS2 ablation inhibits macrophage infiltration, fibrosis, and SCC development in the lungs of KA/KA mice. Macrophage NOS2 was found to circulate inflammation and enhance macrophage migration and survival. NOS2 promotes foamy macrophage formation characterized with impaired lipid metabolism. NOS2 null bone marrow transplantation reduces foamy macrophage numbers and carcinogenesis in KA/KA chimaeras. This finding sheds light on a new mechanism by which macrophage NOS2 increases pulmonary inflammatory responses and macrophage survival and impairs macrophage lipid metabolism, thereby promoting lung SCC formation.
Chasing the signaling run by tri-molecular time-lapse FRET microscopy
Authors: Kuo Hsiang-Ling , Ho Pei-Chuan , Huang Shenq-Shyang , Chang Nan-Shan
Published: April 2018

A feasible design is made to measure three protein/protein interactions to visualize signal pathways by time-lapse Förster resonance energy transfer (FRET) microscopy. When interacting proteins are in close proximity, excitation energy is provided to allow the energy flow from the first molecule to excite the second, followed by energy transfer to the third. By phorbol ester/calcium ionophore stimulation, for example, a real-time complex formation of ectopic IκBα/ERK/WWOX occurs as measured by FRET microscopy, indicative of an ongoing functional signaling. Hyaluronan induces membrane Hyal-2 signaling, which allows FRET measurement of the complex formation of ectopic Smad4/WWOX/Hyal-2 for causing bubbling cell death. If ectopic p53 is recruited to replace Hyal-2, the resulting ectopic Smad4/WWOX/p53 complex induces membrane blebbing without cell death. Together, in this perspective review article, we demonstrate the utilization of time-lapse FRET microscopy to visualize the signaling event via the tri-molecular protein complex formation and their biological outcomes. We show an initial two-protein binding to form the driving force to jumpstart the tri-molecular execution for the signal pathway.
Large-area and bright pulsed electroluminescence in monolayer semiconductors
Authors: Lien Der-Hsien , Amani Matin , Desai Sujay B. , Ahn Geun Ho , Han Kevin , He Jr-Hau , Ager Joel W. , Wu Ming C. , Javey Ali
Published: April 2018

Transition-metal dichalcogenide monolayers have naturally terminated surfaces and can exhibit a near-unity photoluminescence quantum yield in the presence of suitable defect passivation. To date, steady-state monolayer light-emitting devices suffer from Schottky contacts or require complex heterostructures. We demonstrate a transient-mode electroluminescent device based on transition-metal dichalcogenide monolayers (MoS2, WS2, MoSe2, and WSe2) to overcome these problems. Electroluminescence from this dopant-free two-terminal device is obtained by applying an AC voltage between the gate and the semiconductor. Notably, the electroluminescence intensity is weakly dependent on the Schottky barrier height or polarity of the contact. We fabricate a monolayer seven-segment display and achieve the first transparent and bright millimeter-scale light-emitting monolayer semiconductor device.
Mechanistic insights into allosteric regulation of the A2A adenosine G protein-coupled receptor by physiological cations
Authors: Ye Libin , Neale Chris , Sljoka Adnan , Lyda Brent , Pichugin Dmitry , Tsuchimura Nobuyuki , Larda Sacha T. , Pomès Régis , García Angel E. , Ernst Oliver P. , Sunahara Roger K. , Prosser R. Scott
Published: April 2018

Cations play key roles in regulating G-protein-coupled receptors (GPCRs), although their mechanisms are poorly understood. Here,19F NMR is used to delineate the effects of cations on functional states of the adenosine A2AGPCR. While Na+reinforces an inactive ensemble and a partial-agonist stabilized state, Ca2+and Mg2+shift the equilibrium toward active states. Positive allosteric effects of divalent cations are more pronounced with agonist and a G-protein-derived peptide. In cell membranes, divalent cations enhance both the affinity and fraction of the high affinity agonist-bound state. Molecular dynamics simulations suggest high concentrations of divalent cations bridge specific extracellular acidic residues, bringing TM5 and TM6 together at the extracellular surface and allosterically driving open the G-protein-binding cleft as shown by rigidity-transmission allostery theory. An understanding of cation allostery should enable the design of allosteric agents and enhance our understanding of GPCR regulation in the cellular milieu.
A licensing step links AID to transcription elongation for mutagenesis in B cells
Authors: Methot Stephen P. , Litzler Ludivine C. , Subramani Poorani Ganesh , Eranki Anil K. , Fifield Heather , Patenaude Anne-Marie , Gilmore Julian C. , Santiago Gabriel E. , Bagci Halil , Côté Jean-François , Larijani Mani , Verdun Ramiro E. , Di Noia Javier M.
Published: April 2018

Activation-induced deaminase (AID) mutates the immunoglobulin (Ig) genes to initiate somatic hypermutation (SHM) and class switch recombination (CSR) in B cells, thus underpinning antibody responses. AID mutates a few hundred other loci, but most AID-occupied genes are spared. The mechanisms underlying productive deamination versus non-productive AID targeting are unclear. Here we show that three clustered arginine residues define a functional AID domain required for SHM, CSR, and off-target activity in B cells without affecting AID deaminase activity or Escherichia coli mutagenesis. Both wt AID and mutants with single amino acid replacements in this domain broadly associate with Spt5 and chromatin and occupy the promoter of AID target genes. However, mutant AID fails to occupy the corresponding gene bodies and loses association with transcription elongation factors. Thus AID mutagenic activity is determined not by locus occupancy but by a licensing mechanism, which couples AID to transcription elongation.
Designable ultra-smooth ultra-thin solid-electrolyte interphases of three alkali metal anodes
Authors: Gu Yu , Wang Wei-Wei , Li Yi-Juan , Wu Qi-Hui , Tang Shuai , Yan Jia-Wei , Zheng Ming-Sen , Wu De-Yin , Fan Chun-Hai , Hu Wei-Qiang , Chen Zhao-Bin , Fang Yuan , Zhang Qing-Hong , Dong Quan-Feng , Mao Bing-Wei
Published: April 2018

Dendrite growth of alkali metal anodes limited their lifetime for charge/discharge cycling. Here, we report near-perfect anodes of lithium, sodium, and potassium metals achieved by electrochemical polishing, which removes microscopic defects and creates ultra-smooth ultra-thin solid-electrolyte interphase layers at metal surfaces for providing a homogeneous environment. Precise characterizations by AFM force probing with corroborative in-depth XPS profile analysis reveal that the ultra-smooth ultra-thin solid-electrolyte interphase can be designed to have alternating inorganic-rich and organic-rich/mixed multi-layered structure, which offers mechanical property of coupled rigidity and elasticity. The polished metal anodes exhibit significantly enhanced cycling stability, specifically the lithium anodes can cycle for over 200 times at a real current density of 2 mA cm–2 with 100% depth of discharge. Our work illustrates that an ultra-smooth ultra-thin solid-electrolyte interphase may be robust enough to suppress dendrite growth and thus serve as an initial layer for further improved protection of alkali metal anodes.
Cell-free protein synthesis from genomically recoded bacteria enables multisite incorporation of noncanonical amino acids
Authors: Martin Rey W. , Des Soye Benjamin J. , Kwon Yong-Chan , Kay Jennifer , Davis Roderick G. , Thomas Paul M. , Majewska Natalia I. , Chen Cindy X. , Marcum Ryan D. , Weiss Mary Grace , Stoddart Ashleigh E. , Amiram Miriam , Ranji Charna Arnaz K. , Patel Jaymin R. , Isaacs Farren J. , Kelleher Neil L. , Hong Seok Hoon , Jewett Michael C.
Published: April 2018

Cell-free protein synthesis has emerged as a powerful approach for expanding the range of genetically encoded chemistry into proteins. Unfortunately, efforts to site-specifically incorporate multiple non-canonical amino acids into proteins using crude extract-based cell-free systems have been limited by release factor 1 competition. Here we address this limitation by establishing a bacterial cell-free protein synthesis platform based on genomically recoded Escherichia coli lacking release factor 1. This platform was developed by exploiting multiplex genome engineering to enhance extract performance by functionally inactivating negative effectors. Our most productive cell extracts enabled synthesis of 1,780 ± 30 mg/L superfolder green fluorescent protein. Using an optimized platform, we demonstrated the ability to introduce 40 identical p-acetyl-l-phenylalanine residues site specifically into an elastin-like polypeptide with high accuracy of incorporation ( ≥ 98%) and yield (96 ± 3 mg/L). We expect this cell-free platform to facilitate fundamental understanding and enable manufacturing paradigms for proteins with new and diverse chemistries.
Engineering enhanced cellobiohydrolase activity
Authors: Taylor Larry E. , Knott Brandon C. , Baker John O. , Alahuhta P. Markus , Hobdey Sarah E. , Linger Jeffrey G. , Lunin Vladimir V. , Amore Antonella , Subramanian Venkataramanan , Podkaminer Kara , Xu Qi , VanderWall Todd A. , Schuster Logan A. , Chaudhari Yogesh B. , Adney William S. , Crowley Michael F. , Himmel Michael E. , Decker Stephen R. , Beckham Gregg T.
Published: April 2018

Glycoside Hydrolase Family 7 cellobiohydrolases (GH7 CBHs) catalyze cellulose depolymerization in cellulolytic eukaryotes, making them key discovery and engineering targets. However, there remains a lack of robust structure–activity relationships for these industrially important cellulases. Here, we compare CBHs from Trichoderma reesei (TrCel7A) and Penicillium funiculosum (PfCel7A), which exhibit a multi-modular architecture consisting of catalytic domain (CD), carbohydrate-binding module, and linker. We show that PfCel7A exhibits 60% greater performance on biomass than TrCel7A. To understand the contribution of each domain to this improvement, we measure enzymatic activity for a library of CBH chimeras with swapped subdomains, demonstrating that the enhancement is mainly caused by PfCel7A CD. We solve the crystal structure of PfCel7A CD and use this information to create a second library of TrCel7A CD mutants, identifying a TrCel7A double mutant with near-equivalent activity to wild-type PfCel7A. Overall, these results reveal CBH regions that enable targeted activity improvements.
Silicon and glass very large scale microfluidic droplet integration for terascale generation of polymer microparticles
Authors: Yadavali Sagar , Jeong Heon-Ho , Lee Daeyeon , Issadore David
Published: April 2018

Microfluidic chips can generate emulsions, which can be used to synthesize polymer microparticles that have superior pharmacological performance compared to particles prepared by conventional techniques. However, low production rates of microfluidics remains a challenge to successfully translate laboratory discoveries to commercial manufacturing. We present a silicon and glass device that incorporates an array of 10,260 (285 × 36) microfluidic droplet generators that uses only a single set of inlets and outlets, increasing throughput by >10,000× compared to microfluidics with a single generator. Our design breaks the tradeoff between the number of generators and the maximum throughput of individual generators by incorporating high aspect ratio flow resistors. We test these design strategies by generating hexadecane microdroplets at >1 trillion droplets per h with a coefficient of variation CV <3%. To demonstrate the synthesis of biocompatible microparticles, we generated 8–16 µm polycaprolactone particles with a CV <5% at a rate of 277 g h−1.
Evidence for functional pre-coupled complexes of receptor heteromers and adenylyl cyclase
Authors: Navarro Gemma , Cordomí Arnau , Casadó-Anguera Verónica , Moreno Estefanía , Cai Ning-Sheng , Cortés Antoni , Canela Enric I. , Dessauer Carmen W. , Casadó Vicent , Pardo Leonardo , Lluís Carme , Ferré Sergi
Published: April 2018

G protein-coupled receptors (GPCRs), G proteins and adenylyl cyclase (AC) comprise one of the most studied transmembrane cell signaling pathways. However, it is unknown whether the ligand-dependent interactions between these signaling molecules are based on random collisions or the rearrangement of pre-coupled elements in a macromolecular complex. Furthermore, it remains controversial whether a GPCR homodimer coupled to a single heterotrimeric G protein constitutes a common functional unit. Using a peptide-based approach, we here report evidence for the existence of functional pre-coupled complexes of heteromers of adenosine A2A receptor and dopamine D2 receptor homodimers coupled to their cognate Gs and Gi proteins and to subtype 5 AC. We also demonstrate that this macromolecular complex provides the necessary frame for the canonical Gs-Gi interactions at the AC level, sustaining the ability of a Gi-coupled GPCR to counteract AC activation mediated by a Gs-coupled GPCR.
Low ocean-floor rises regulate subpolar sea surface temperature by forming baroclinic jets
Authors: Mitsudera H. , Miyama T. , Nishigaki H. , Nakanowatari T. , Nishikawa H. , Nakamura T. , Wagawa T. , Furue R. , Fujii Y. , Ito S.
Published: April 2018

Sea surface temperature (SST) fronts in mid- to high-latitude oceans have significant impacts on extratropical atmospheric circulations and climate. In the western subarctic Pacific, sharp SST fronts form between the cold subarctic water and the recently found quasi-stationary jets that advect warm waters originating in the Kuroshio northeastward. Here we present a new mechanism of the jet formation paying attention to the propagation of baroclinic Rossby waves that is deflected by eddy-driven barotropic flows over bottom rises, although their height is low (~500 m) compared with the depth of the North Pacific Ocean (~6000 m). Steered by the barotropic flows, Rossby waves bring a thicker upper layer from the subtropical gyre and a thinner upper layer from the subarctic gyre, thereby creating a thickness jump, hence a surface jet, where they converge. This study reveals an overlooked role of low-rise bottom topography in regulating SST anomalies in subpolar oceans.
Impact of evolving greenhouse gas forcing on the warming signal in regional climate model experiments
Authors: Jerez S. , López-Romero J. M. , Turco M. , Jiménez-Guerrero P. , Vautard R. , Montávez J. P.
Published: April 2018

Variations in the atmospheric concentrations of greenhouse gases (GHG) may not be included as external forcing when running regional climate models (RCMs); at least, this is a non-regulated, non-documented practice. Here we investigate the so far unexplored impact of considering the rising evolution of the CO2, CH4, and N2O atmospheric concentrations on near-surface air temperature (TAS) trends, for both the recent past and the near future, as simulated by a state-of-the-art RCM over Europe. The results show that the TAS trends are significantly affected by 1–2 K century−1, which under 1.5 °C global warming translates into a non-negligible impact of up to 1 K in the regional projections of TAS, similarly affecting projections for maximum and minimum temperatures. In some cases, these differences involve a doubling signal, laying further claim to careful reconsideration of the RCM setups with regard to the inclusion of GHG concentrations as an evolving external forcing which, for the sake of research reproducibility and reliability, should be clearly documented in the literature.
Asymmetric synthesis of γ-branched amines via rhodium-catalyzed reductive amination
Authors: Wu Zhao , Laffoon Summer D. , Hull Kami L.
Published: April 2018

Amines bearing γ-stereocenters are highly important structural motifs in many biologically active compounds. However, reported enantioselective syntheses of these molecules are indirect and often require multiple steps. Herein, we report a general asymmetric route for the one-pot synthesis of chiral γ-branched amines through the highly enantioselective isomerization of allylamines, followed by enamine exchange and subsequent chemoselective reduction. This protocol is suitable for establishing various tertiary stereocenters, including those containing dialkyl, diaryl, cyclic, trifluoromethyl, difluoromethyl, and silyl substituents, which allows for a rapid and modular synthesis of many chiral γ-branched amines. To demonstrate the synthetic utility, Terikalant and Tolterodine are synthesized using this method with high levels of enantioselectivity.
Biomimetic temporal self-assembly via fuel-driven controlled supramolecular polymerization
Authors: Mishra Ananya , Korlepara Divya B. , Kumar Mohit , Jain Ankit , Jonnalagadda Narendra , Bejagam Karteek K. , Balasubramanian Sundaram , George Subi J.
Published: April 2018

Temporal control of supramolecular assemblies to modulate the structural and transient characteristics of synthetic nanostructures is an active field of research within supramolecular chemistry. Molecular designs to attain temporal control have often taken inspiration from biological assemblies. One such assembly in Nature which has been studied extensively, for its well-defined structure and programmable self-assembly, is the ATP-driven seeded self-assembly of actin. Here we show, in a synthetic manifestation of actin self-assembly, an ATP-selective and ATP-fuelled, controlled supramolecular polymerization of a phosphate receptor functionalised monomer. It undergoes fuel-driven nucleation and seeded growth that provide length control and narrow dispersity of the resultant assemblies. Furthermore, coupling via ATP-hydrolysing enzymes yielded its transient characteristics. These results will usher investigations into synthetic analogues of important biological self-assembly motifs and will prove to be a significant advancement toward biomimetic temporally programmed materials.
Scalable synthesis enabling multilevel bio-evaluations of natural products for discovery of lead compounds
Authors: Zhu Lizhi , Ma Wenjing , Zhang Mengxun , Lee Magnolia Muk-Lan , Wong Wing-Yan , Chan Brandon Dow , Yang Qianqian , Wong Wing-Tak , Tai William Chi-Shing , Lee Chi-Sing
Published: April 2018

Challenges in the development of anti-cancer chemotherapeutics continue to exist, particularly with respect to adverse effects and development of resistance, underlining the need for novel drugs with good safety profiles. Natural products have proven to be a fertile ground for exploitation, and development of anti-cancer drugs from structurally complex natural products holds promise. Unfortunately, this approach is often hindered by low isolation yields and limited information from preliminary cell-based assays. Here we report a concise and scalable synthesis of a series of low-abundance Isodon diterpenoids (a large class of natural products with over 1000 members isolated from the herbs of genus Isodon, which are well-known folk medicines for the treatment of inflammation and cancer), including eriocalyxin B, neolaxiflorin L and xerophilusin I. These scalable syntheses enable multilevel bio-evaluation of the natural products, in which we identify neolaxiflorin L as a promising anti-cancer drug candidate.
Mice lacking the mitochondrial exonuclease MGME1 accumulate mtDNA deletions without developing progeria
Authors: Matic Stanka , Jiang Min , Nicholls Thomas J. , Uhler Jay P. , Dirksen-Schwanenland Caren , Polosa Paola Loguercio , Simard Marie-Lune , Li Xinping , Atanassov Ilian , Rackham Oliver , Filipovska Aleksandra , Stewart James B. , Falkenberg Maria , Larsson Nils-Göran , Milenkovic Dusanka
Published: April 2018

Replication of mammalian mitochondrial DNA (mtDNA) is an essential process that requires high fidelity and control at multiple levels to ensure proper mitochondrial function. Mutations in the mitochondrial genome maintenance exonuclease 1 (MGME1) gene were recently reported in mitochondrial disease patients. Here, to study disease pathophysiology, we generated Mgme1 knockout mice and report that homozygous knockouts develop depletion and multiple deletions of mtDNA. The mtDNA replication stalling phenotypes vary dramatically in different tissues of Mgme1 knockout mice. Mice with MGME1 deficiency accumulate a long linear subgenomic mtDNA species, similar to the one found in mtDNA mutator mice, but do not develop progeria. This finding resolves a long-standing debate by showing that point mutations of mtDNA are the main cause of progeria in mtDNA mutator mice. We also propose a role for MGME1 in the regulation of replication and transcription termination at the end of the control region of mtDNA.
Downregulation of cytoplasmic DNases is implicated in cytoplasmic DNA accumulation and SASP in senescent cells
Authors: Takahashi Akiko , Loo Tze Mun , Okada Ryo , Kamachi Fumitaka , Watanabe Yoshihiro , Wakita Masahiro , Watanabe Sugiko , Kawamoto Shimpei , Miyata Kenichi , Barber Glen N. , Ohtani Naoko , Hara Eiji
Published: April 2018

Accumulating evidence indicates that the senescence-associated secretory phenotype (SASP) contributes to many aspects of physiology and disease. Thus, controlling the SASP will have tremendous impacts on our health. However, our understanding of SASP regulation is far from complete. Here, we show that cytoplasmic accumulation of nuclear DNA plays key roles in the onset of SASP. Although both DNase2 and TREX1 rapidly remove the cytoplasmic DNA fragments emanating from the nucleus in pre-senescent cells, the expression of these DNases is downregulated in senescent cells, resulting in the cytoplasmic accumulation of nuclear DNA. This causes the aberrant activation of cGAS-STING cytoplasmic DNA sensors, provoking SASP through induction of interferon-β. Notably, the blockage of this pathway prevents SASP in senescent hepatic stellate cells, accompanied by a decline of obesity-associated hepatocellular carcinoma development in mice. These findings provide valuable new insights into the roles and mechanisms of SASP and possibilities for their control.
Spatial fidelity of workers predicts collective response to disturbance in a social insect
Authors: Crall James D. , Gravish Nick , Mountcastle Andrew M. , Kocher Sarah D. , Oppenheimer Robert L. , Pierce Naomi E. , Combes Stacey A.
Published: April 2018

Individuals in social insect colonies cooperate to perform collective work. While colonies often respond to changing environmental conditions by flexibly reallocating workers to different tasks, the factors determining which workers switch and why are not well understood. Here, we use an automated tracking system to continuously monitor nest behavior and foraging activity of uniquely identified workers from entire bumble bee (Bombus impatiens) colonies foraging in a natural outdoor environment. We show that most foraging is performed by a small number of workers and that the intensity and distribution of foraging is actively regulated at the colony level in response to forager removal. By analyzing worker nest behavior before and after forager removal, we show that spatial fidelity of workers within the nest generates uneven interaction with relevant localized information sources, and predicts which workers initiate foraging after disturbance. Our results highlight the importance of spatial fidelity for structuring information flow and regulating collective behavior in social insect colonies.
Microglia remodel synapses by presynaptic trogocytosis and spine head filopodia induction
Authors: Weinhard Laetitia , di Bartolomei Giulia , Bolasco Giulia , Machado Pedro , Schieber Nicole L. , Neniskyte Urte , Exiga Melanie , Vadisiute Auguste , Raggioli Angelo , Schertel Andreas , Schwab Yannick , Gross Cornelius T.
Published: April 2018

Microglia are highly motile glial cells that are proposed to mediate synaptic pruning during neuronal circuit formation. Disruption of signaling between microglia and neurons leads to an excess of immature synaptic connections, thought to be the result of impaired phagocytosis of synapses by microglia. However, until now the direct phagocytosis of synapses by microglia has not been reported and fundamental questions remain about the precise synaptic structures and phagocytic mechanisms involved. Here we used light sheet fluorescence microscopy to follow microglia–synapse interactions in developing organotypic hippocampal cultures, complemented by a 3D ultrastructural characterization using correlative light and electron microscopy (CLEM). Our findings define a set of dynamic microglia–synapse interactions, including the selective partial phagocytosis, or trogocytosis (trogo-: nibble), of presynaptic structures and the induction of postsynaptic spine head filopodia by microglia. These findings allow us to propose a mechanism for the facilitatory role of microglia in synaptic circuit remodeling and maturation.
Integrative proteomics in prostate cancer uncovers robustness against genomic and transcriptomic aberrations during disease progression
Authors: Latonen Leena , Afyounian Ebrahim , Jylhä Antti , Nättinen Janika , Aapola Ulla , Annala Matti , Kivinummi Kati K. , Tammela Teuvo T. L. , Beuerman Roger W. , Uusitalo Hannu , Nykter Matti , Visakorpi Tapio
Published: April 2018

To understand functional consequences of genetic and transcriptional aberrations in prostate cancer, the proteomic changes during disease formation and progression need to be revealed. Here we report high-throughput mass spectrometry on clinical tissue samples of benign prostatic hyperplasia (BPH), untreated primary prostate cancer (PC) and castration resistant prostate cancer (CRPC). Each sample group shows a distinct protein profile. By integrative analysis we show that, especially in CRPC, gene copy number, DNA methylation, and RNA expression levels do not reliably predict proteomic changes. Instead, we uncover previously unrecognized molecular and pathway events, for example, several miRNA target correlations present at protein but not at mRNA level. Notably, we identify two metabolic shifts in the citric acid cycle (TCA cycle) during prostate cancer development and progression. Our proteogenomic analysis uncovers robustness against genomic and transcriptomic aberrations during prostate cancer progression, and significantly extends understanding of prostate cancer disease mechanisms.
Divergent midbrain circuits orchestrate escape and freezing responses to looming stimuli in mice
Authors: Shang Congping , Chen Zijun , Liu Aixue , Li Yang , Zhang Jiajing , Qu Baole , Yan Fei , Zhang Yaning , Liu Weixiu , Liu Zhihui , Guo Xiaofei , Li Dapeng , Wang Yi , Cao Peng
Published: April 2018

Animals respond to environmental threats, e.g. looming visual stimuli, with innate defensive behaviors such as escape and freezing. The key neural circuits that participate in the generation of such dimorphic defensive behaviors remain unclear. Here we show that the dimorphic behavioral patterns triggered by looming visual stimuli are mediated by parvalbumin-positive (PV+) projection neurons in mouse superior colliculus (SC). Two distinct groups of SC PV+ neurons form divergent pathways to transmit threat-relevant visual signals to neurons in the parabigeminal nucleus (PBGN) and lateral posterior thalamic nucleus (LPTN). Activations of PV+ SC-PBGN and SC-LPTN pathways mimic the dimorphic defensive behaviors. The PBGN and LPTN neurons are co-activated by looming visual stimuli. Bilateral inactivation of either nucleus results in the defensive behavior dominated by the other nucleus. Together, these data suggest that the SC orchestrates dimorphic defensive behaviors through two separate tectofugal pathways that may have interactions.
AUX1-mediated root hair auxin influx governs SCFTIR1/AFB-type Ca2+ signaling
Authors: Dindas Julian , Scherzer Sönke , Roelfsema M. Rob G. , von Meyer Katharina , Müller Heike M. , Al-Rasheid K. A. S. , Palme Klaus , Dietrich Petra , Becker Dirk , Bennett Malcolm J. , Hedrich Rainer
Published: April 2018

Auxin is a key regulator of plant growth and development, but the causal relationship between hormone transport and root responses remains unresolved. Here we describe auxin uptake, together with early steps in signaling, inArabidopsisroot hairs. Using intracellular microelectrodes we show membrane depolarization, in response to IAA in a concentration- and pH-dependent manner. This depolarization is strongly impaired inaux1mutants, indicating that AUX1 is the major transporter for auxin uptake in root hairs. Local intracellular auxin application triggers Ca2+signals that propagate as long-distance waves between root cells and modulate their auxin responses. AUX1-mediated IAA transport, as well as IAA-triggered calcium signals, are blocked by treatment with the SCFTIR1/AFB- inhibitor auxinole. Further, they are strongly reduced in thetir1afb2afb3and thecngc14mutant. Our study reveals that the AUX1 transporter, the SCFTIR1/AFBreceptor and the CNGC14 Ca2+channel, mediate fast auxin signaling in roots.
Fluorescent label-free quantitative detection of nano-sized bioparticles using a pillar array
Authors: Zeming Kerwin Kwek , Salafi Thoriq , Shikha Swati , Zhang Yong
Published: April 2018

Disease diagnostics requires detection and quantification of nano-sized bioparticles including DNA, proteins, viruses, and exosomes. Here, a fluorescent label-free method for sensitive detection of bioparticles is explored using a pillar array with micrometer-sized features in a deterministic lateral displacement (DLD) device. The method relies on measuring changes in size and/or electrostatic charges of 1 µm polymer beads due to the capture of target bioparticles on the surface. These changes can be sensitively detected through the lateral displacement of the beads in the DLD array, wherein the lateral shifts in the output translates to a quantitative measurement of bioparticles bound to the bead. The detection of albumin protein and nano-sized polymer vesicles with a concentration as low as 10 ng mL−1 (150 pM) and 3.75 μg mL−1, respectively, is demonstrated. This label-free method holds potential for point-of-care diagnostics, as it is low-cost, fast, sensitive, and only requires a standard laboratory microscope for detection.
Experimentally quantifying anion polarizability at the air/water interface
Authors: Tong Yujin , Zhang Igor Ying , Campen R. Kramer
Published: April 2018

The adsorption of large, polarizable anions from aqueous solution on the air/water interface controls important atmospheric chemistry and is thought to resemble anion adsorption at hydrophobic interfaces generally. While the favourability of adsorption of such ions is clear, quantifying adsorption thermodynamics has proven challenging because it requires accurate description of the structure of the anion and its solvation shell at the interface. In principle anion polarizability offers a structural window, but to the best of our knowledge there has so far been no experimental technique that allowed its characterization with interfacial specificity. Here, we meet this challenge using interface-specific vibrational spectroscopy of Cl–O vibrations of the $${\mathrm{ClO}}_4^ -$$

ClO

4

-

anion at the air/water interface and report that the interface breaks the symmetry of the anion, the anisotropy of $${\mathrm{ClO}}_4^ -$$

ClO

4

-

’s polarizability tensor is more than two times larger than in bulk water and concentration dependent, and concentration-dependent polarizability changes are consistent with correlated changes in surface tension.
Cryo-EM structure of the polycystic kidney disease-like channel PKD2L1
Authors: Su Qiang , Hu Feizhuo , Liu Yuxia , Ge Xiaofei , Mei Changlin , Yu Shengqiang , Shen Aiwen , Zhou Qiang , Yan Chuangye , Lei Jianlin , Zhang Yanqing , Liu Xiaodong , Wang Tingliang
Published: April 2018

PKD2L1, also termed TRPP3 from the TRPP subfamily (polycystic TRP channels), is involved in the sour sensation and other pH-dependent processes. PKD2L1 is believed to be a nonselective cation channel that can be regulated by voltage, protons, and calcium. Despite its considerable importance, the molecular mechanisms underlying PKD2L1 regulations are largely unknown. Here, we determine the PKD2L1 atomic structure at 3.38 Å resolution by cryo-electron microscopy, whereby side chains of nearly all residues are assigned. Unlike its ortholog PKD2, the pore helix (PH) and transmembrane segment 6 (S6) of PKD2L1, which are involved in upper and lower-gate opening, adopt an open conformation. Structural comparisons of PKD2L1 with a PKD2-based homologous model indicate that the pore domain dilation is coupled to conformational changes of voltage-sensing domains (VSDs) via a series of π–π interactions, suggesting a potential PKD2L1 gating mechanism.
The oldest magnetic record in our solar system identified using nanometric imaging and numerical modeling
Authors: Shah Jay , Williams Wyn , Almeida Trevor P. , Nagy Lesleis , Muxworthy Adrian R. , Kovács András , Valdez-Grijalva Miguel A. , Fabian Karl , Russell Sara S. , Genge Matthew J. , Dunin-Borkowski Rafal E.
Published: April 2018

Recordings of magnetic fields, thought to be crucial to our solar system’s rapid accretion, are potentially retained in unaltered nanometric low-Ni kamacite (~ metallic Fe) grains encased within dusty olivine crystals, found in the chondrules of unequilibrated chondrites. However, most of these kamacite grains are magnetically non-uniform, so their ability to retain four-billion-year-old magnetic recordings cannot be estimated by previous theories, which assume only uniform magnetization. Here, we demonstrate that non-uniformly magnetized nanometric kamacite grains are stable over solar system timescales and likely the primary carrier of remanence in dusty olivine. By performing in-situ temperature-dependent nanometric magnetic measurements using off-axis electron holography, we demonstrate the thermal stability of multi-vortex kamacite grains from the chondritic Bishunpur meteorite. Combined with numerical micromagnetic modeling, we determine the stability of the magnetization of these grains. Our study shows that dusty olivine kamacite grains are capable of retaining magnetic recordings from the accreting solar system.