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The December 2019 outbreak of a novel respiratory virus, SARS-CoV-2, has become an ongoing global pandemic due in part to the challenge of identifying symptomatic, asymptomatic, and pre-symptomatic carriers of the virus. CRISPR diagnostics can augment gold-standard PCR-based testing if they can be made rapid, portable, and accurate. Here, we report the development of an amplification-free CRISPR-Cas13a assay for direct detection of SARS-CoV-2 from nasal swab RNA that can be read with a mobile phone microscope. The assay achieved â¼100 copies/µL sensitivity in under 30 min of measurement time and accurately detected pre-extracted RNA from a set of positive clinical samples in under 5 min. We combined crRNAs targeting SARS-CoV-2 RNA to improve sensitivity and specificity and directly quantified viral load using enzyme kinetics. Integrated with a reader device based on a mobile phone, this assay has the potential to enable rapid, low-cost, point-of-care screening for SARS-CoV-2.
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Teste de Ácido Nucleico para COVID-19/métodos , Telefone Celular/instrumentação , Imagem Óptica/métodos , RNA Viral/análise , Carga Viral/métodos , Animais , Teste de Ácido Nucleico para COVID-19/economia , Teste de Ácido Nucleico para COVID-19/instrumentação , Sistemas CRISPR-Cas , Linhagem Celular , Proteínas do Nucleocapsídeo de Coronavírus/genética , Humanos , Nasofaringe/virologia , Imagem Óptica/instrumentação , Fosfoproteínas/genética , Testes Imediatos , Interferência de RNA , RNA Viral/genética , Sensibilidade e Especificidade , Carga Viral/economia , Carga Viral/instrumentaçãoRESUMO
Rotavirus (RV) encounters intestinal epithelial cells amidst diverse microbiota, opening possibilities of microbes influencing RV infection. Although RV clearance typically requires adaptive immunity, we unintentionally generated RV-resistant immunodeficient mice, which, we hypothesized, reflected select microbes protecting against RV. Accordingly, such RV resistance was transferred by co-housing and fecal transplant. RV-protecting microbiota were interrogated by heat, filtration, and antimicrobial agents, followed by limiting dilution transplant to germ-free mice and microbiome analysis. This approach revealed that segmented filamentous bacteria (SFB) were sufficient to protect mice against RV infection and associated diarrhea. Such protection was independent of previously defined RV-impeding factors, including interferon, IL-17, and IL-22. Colonization of the ileum by SFB induced changes in host gene expression and accelerated epithelial cell turnover. Incubation of RV with SFB-containing feces reduced infectivity in vitro, suggesting direct neutralization of RV. Thus, independent of immune cells, SFB confer protection against certain enteric viral infections and associated diarrheal disease.
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Imunidade Adaptativa/genética , Diarreia/microbiologia , Mucosa Intestinal/microbiologia , Infecções por Rotavirus/microbiologia , Animais , Anti-Infecciosos/farmacologia , Bactérias/genética , Bactérias/metabolismo , Diarreia/prevenção & controle , Diarreia/virologia , Fezes/microbiologia , Regulação da Expressão Gênica/genética , Humanos , Íleo/microbiologia , Íleo/patologia , Íleo/virologia , Interferons/genética , Interleucina-17/genética , Interleucinas/genética , Mucosa Intestinal/patologia , Mucosa Intestinal/virologia , Camundongos , Microbiota/genética , Rotavirus/patogenicidade , Infecções por Rotavirus/prevenção & controle , Infecções por Rotavirus/virologia , Interleucina 22RESUMO
The gut of healthy human neonates is usually devoid of viruses at birth, but quickly becomes colonized, which-in some cases-leads to gastrointestinal disorders1-4. Here we show that the assembly of the viral community in neonates takes place in distinct steps. Fluorescent staining of virus-like particles purified from infant meconium or early stool samples shows few or no particles, but by one month of life particle numbers increase to 109 per gram, and these numbers seem to persist throughout life5-7. We investigated the origin of these viral populations using shotgun metagenomic sequencing of virus-enriched preparations and whole microbial communities, followed by targeted microbiological analyses. Results indicate that, early after birth, pioneer bacteria colonize the infant gut and by one month prophages induced from these bacteria provide the predominant population of virus-like particles. By four months of life, identifiable viruses that replicate in human cells become more prominent. Multiple human viruses were more abundant in stool samples from babies who were exclusively fed on formula milk compared with those fed partially or fully on breast milk, paralleling reports that breast milk can be protective against viral infections8-10. Bacteriophage populations also differed depending on whether or not the infant was breastfed. We show that the colonization of the infant gut is stepwise, first mainly by temperate bacteriophages induced from pioneer bacteria, and later by viruses that replicate in human cells; this second phase is modulated by breastfeeding.
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Aleitamento Materno , Trato Gastrointestinal/virologia , Vírus/isolamento & purificação , Adulto , Bacteriólise , Bacteriófagos/genética , Bacteriófagos/isolamento & purificação , Fezes/virologia , Feminino , Microbioma Gastrointestinal , Trato Gastrointestinal/microbiologia , Humanos , Lactente , Recém-Nascido , Lisogenia , Masculino , Mecônio/virologia , Prófagos/genética , Prófagos/isolamento & purificação , Vírus/genéticaRESUMO
α-synuclein (α-Syn) is a presynaptic protein that is involved in Parkinson's and other neurodegenerative diseases and binds to negatively charged phospholipids. Previously, we reported that α-Syn clusters synthetic proteoliposomes that mimic synaptic vesicles. This vesicle-clustering activity depends on a specific interaction of α-Syn with anionic phospholipids. Here, we report that α-Syn surprisingly also interacts with the neutral phospholipid lysophosphatidylcholine (lysoPC). Even in the absence of anionic lipids, lysoPC facilitates α-Syn-induced vesicle clustering but has no effect on Ca2+-triggered fusion in a single vesicle-vesicle fusion assay. The A30P mutant of α-Syn that causes familial Parkinson disease has a reduced affinity to lysoPC and does not induce vesicle clustering. Taken together, the α-Syn-lysoPC interaction may play a role in α-Syn function.
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Doença de Parkinson , alfa-Sinucleína , Humanos , alfa-Sinucleína/genética , alfa-Sinucleína/metabolismo , Vesículas Sinápticas/metabolismo , Lisofosfatidilcolinas/metabolismo , Doença de Parkinson/genética , Doença de Parkinson/metabolismo , Fosfolipídeos/metabolismoRESUMO
Phase transitions of Mn-based cathode materials associated with the charge and discharge process play a crucial role on the rate capability and cycle life of zinc ion batteries. Herein, a microscopic electrochemical failure mechanism of Zn-MnO2 batteries during the phase transitions from δ-MnO2 to λ-ZnMn2O4 is presented via systematic first-principle investigation. The initial insertion of Zn2+ intensifies the rearrangement of Mn. This is completed by the electrostatic repulsion and co-migration between guest and host ions, leading to the formation of λ-ZnMn2O4. The Mn relocation barrier for the λ-ZnMn2O4 formation path with 1.09 eV is significantly lower than the δ-MnO2 re-formation path with 2.14 eV, indicating the irreversibility of the layered-to-spinel transition. Together with the phase transition, the rearrangement of Mn elevates the Zn2+ migration barrier from 0.31 to 2.28 eV, resulting in poor rate performance. With the increase of charge-discharge cycles, irreversible and inactive λ-ZnMn2O4 products accumulate on the electrode, causing continuous capacity decay of the Zn-MnO2 battery.
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Fe-based 2D materials exhibit rich chemical compositions and structures, which may imply many unique physical properties and promising applications. However, achieving controllable preparation of ultrathin non-layered FeS crystal on SiO2/Si substrate remains a challenge. Herein, the influence of temperature and molecular sieves is reported on the synthesis of ultrathin FeS nanosheets with a thickness as low as 2.3 nm by molecular sieves-assisted chemical vapor deposition (CVD). The grown FeS nanosheets exhibit a non-layered hexagonal NiAs structure and belong to the P63/mmc space group. The inverted symmetry broken structure is confirmed by the angle-resolved second harmonic generation (SHG) test. In particular, the 2D FeS nanosheets exhibit exceptional metallic behavior, with conductivity up to 1.63 × 106 S m-1 at 300 K for an 8 nm thick sample, which is higher than that of reported 2D metallic materials. This work provides a significant contribution to the synthesis and characterization of 2D non-layered Fe-based materials.
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AMPA glutamate receptors (AMPARs) play a pivotal role in excitatory neurotransmission, particularly in the hippocampus where the TARP γ-8 subunit is enriched and serves as a target for emerging anti-epileptic drugs. To enable inâ vivo visualization of TARP γ-8 distribution and expression by positron emission tomography (PET), this study focuses on the development of novel 18 F-labeled TARP γ-8 inhibitors and their corresponding precursors, stemming from the azabenzimidazole scaffold. The resulting radioligands [18 F]TARP-2204 and [18 F]TARP-2205 were successfully synthesized with acceptable radiochemical yield, high molar activity, and excellent radiochemical purity. In vitro autoradiography demonstrates high level of specific binding of [18 F]TARP-2205 to TARP γ-8 in both rat and nonhuman primate brain tissues. However, unexpected radiodefluorination in PET imaging studies of rodents emphasizes the need for further structural refinement. This work serves as an excellent starting point for the development of future 18 F-labeled TARP γ-8 PET tracers, offering valuable insights into medicinal chemistry design, radiosynthesis and subsequent PET evaluation.
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Tomografia por Emissão de Pósitrons , Receptores de AMPA , Ratos , Animais , Receptores de AMPA/metabolismo , Tomografia por Emissão de Pósitrons/métodos , HipocampoRESUMO
SUMMARY: The Metagenomic Intra-Species Diversity Analysis System (MIDAS) is a scalable metagenomic pipeline that identifies single nucleotide variants (SNVs) and gene copy number variants in microbial populations. Here, we present MIDAS2, which addresses the computational challenges presented by increasingly large reference genome databases, while adding functionality for building custom databases and leveraging paired-end reads to improve SNV accuracy. This fast and scalable reengineering of the MIDAS pipeline enables thousands of metagenomic samples to be efficiently genotyped. AVAILABILITY AND IMPLEMENTATION: The source code is available at https://github.com/czbiohub/MIDAS2. SUPPLEMENTARY INFORMATION: Supplementary data are available at Bioinformatics online.
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Metagenoma , Software , Metagenômica , Genótipo , Bases de Dados FactuaisRESUMO
BACKGROUND: Arterial baroreflex dysfunction, like many other central nervous system disorders, involves disruption of the blood-brain barrier, but what causes such disruption in ABR dysfunction is unclear. Here we explored the potential role of platelets in this disruption. METHODS: ABR dysfunction was induced in rats using sinoaortic denervation, and the effects on integrity of the blood-brain barrier were explored based on leakage of Evans blue or FITC-dextran, while the effects on expression of CD40L in platelets and of key proteins in microvascular endothelial cells were explored using immunohistochemistry, western blotting and enzyme-linked immunosorbent assay. Similar experiments were carried out in rat brain microvascular endothelial cell line, which we exposed to platelets taken from rats with ABR dysfunction. RESULTS: Sinoaortic denervation permeabilized the blood-brain barrier and downregulated zonula occludens-1 and occludin in rat brain, while upregulating expression of CD40L on the surface of platelets and stimulating platelet aggregation. Similar effects of permeabilization and downregulation were observed in healthy rats that received platelets from animals with ABR dysfunction, and in rat brain microvascular endothelial cells, but only in the presence of lipopolysaccharide. These effects were associated with activation of NF-κB signaling and upregulation of matrix metalloprotease-9. These effects of platelets from animals with ABR dysfunction were partially blocked by neutralizing antibody against CD40L or the platelet inhibitor clopidogrel. CONCLUSION: During ABR dysfunction, platelets may disrupt the blood-brain barrier when CD40L on their surface activates NF-kB signaling within cerebral microvascular endothelial cells, leading to upregulation of matrix metalloprotease-9. Our findings imply that targeting CD40L may be effective against cerebral diseases involving ABR dysfunction.
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Barorreflexo , Plaquetas , Barreira Hematoencefálica , Ligante de CD40 , Permeabilidade Capilar , Modelos Animais de Doenças , Células Endoteliais , Metaloproteinase 9 da Matriz , NF-kappa B , Ratos Sprague-Dawley , Transdução de Sinais , Animais , Barreira Hematoencefálica/metabolismo , Barreira Hematoencefálica/fisiopatologia , Barreira Hematoencefálica/patologia , Plaquetas/metabolismo , Masculino , Células Endoteliais/metabolismo , Ligante de CD40/metabolismo , Metaloproteinase 9 da Matriz/metabolismo , NF-kappa B/metabolismo , Proteína da Zônula de Oclusão-1/metabolismo , Ocludina/metabolismo , Linhagem Celular , Agregação Plaquetária , Pressão Arterial , RatosRESUMO
Conventional techniques for the closure of wounds, such as sutures and staples, have significant drawbacks that can negatively impact wound healing. Tissue adhesives have emerged as promising alternatives, but poor adhesion, low mechanical properties, and toxicity have hindered their widespread clinical adoption. In this work, a dual modified, aldehyde and methacrylate hyaluronic acid (HA) biopolymer (HA-MA-CHO) has been synthesized through a simplified route for use as a double cross-linked network (DCN) hydrogel (HA-MA-CHO-DCN) adhesive for the effective closure and sealing of wounds. HA-MA-CHO-DCN cross-links in two stages: initial cross-linking of the aldehyde functionality (CHO) of HA-MA-CHO using a disulfide-containing cross-linker, 3,3'-dithiobis (propionic hydrazide) (DTPH), leading to the formation of a self-healing injectable gel, followed by further cross-linking via ultraviolet (UV) initiated polymerization of the methacrylate (MA) functionality. This hydrogel adhesive shows a stable swelling behavior and remarkable versatility as the storage modulus (G') has shown to be highly tunable (103-105 Pa) for application to many different wound environments. The new HA-MA-CHO-DCN hydrogel showed excellent adhesive properties by surpassing the burst pressure and lap-shear strength for the widely used bovine serum albumin-glutaraldehyde (BSAG) glue while maintaining excellent cell viability.
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Ácido Hialurônico , Hidrogéis , Hidrogéis/química , Ácido Hialurônico/química , Adesivos , Glutaral , MetacrilatosRESUMO
Blue-emitting colloidal CsPbX3 (X = Br, Cl, or I) perovskite nanocrystals have emerged as one of the most fascinating materials for optoelectronic applications. However, their applicability is hindered by poor stability and a low photoluminescence efficiency. Herein, highly stable CsPbBr3 nanoplatelets exhibiting intense blue luminescence are fabricated by employing a strategy in which the morphology is regulated and the surface is subjected to dual passivation through the incorporation of zirconium acetylacetonate [Zr(acac)4]. The passivated CsPbBr3 nanocrystals exhibit adjustable light emission from green to dark blue and a controllable morphology from nanocubes (NCs) to nanoplatelets (NPLs) and nanorods accomplished by varying the content of Zr(acac)4. The optimized NPLs are characterized by a bright blue emission with a central wavelength of 459 nm and a high photoluminescence quantum yield of 90%. The addition of Zr(acac)4 in the synthesis of CsPbBr3 induces oriented growth with a two-dimensional morphology. The Zr(acac)4 can repair the surface defects of the nanocrystal surface, and the surface is also capped with the Zr(OH)4 cluster layer. Therefore, the passivated blue-emitting NPLs exhibit outstanding stability compared to that of pristine NPLs during long-term storage and exposure to light. This work provides a novel strategy for fabricating highly stable PNCs with deep-blue emission and widens their potential applications in blue-emitting optoelectronic devices.
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Salt-sensitivity hypertension (SSHTN) is an independent predictor for cardiovascular mortality. VEGFC has been reported to be a protective role in SSHTN and hypertensive kidney injury. However, the underlying mechanisms remain largely unclear. The current study aimed to explore the protective effects and mechanisms of VEGFC against SSHTN and hypertensive nephropathy. Here, we reported that VEGFC attenuated high blood pressure as well as protected against renal inflammation and fibrosis in SSHTN mice. Moreover, VEGFC suppressed the activation of renal NLRP3 inflammasome in SSHTN mice. In vitro, we found VEGFC inhibited NLRP3 inflammasome activation, meanwhile, upregulated autophagy in high-salt-induced macrophages, while these effects were reversed by an autophagy inhibitor 3MA. Furthermore, in vivo, 3MA pretreatment weakened the protective effects of VEGFC on SSHTN and hypertensive nephropathy. Mechanistically, VEGF receptor 3 (VEGFR3) kinase domain activated AMPK by promoting the phosphorylation at Thr183 via binding to AMPK, thus enhancing autophagy activity in the context of high-salt-induced macrophages. These findings indicated that VEGFC inhibited NLRP3 inflammasome activation by promoting VEGFR3-AMPK-dependent autophagy pathway in high-salt-induced macrophages, which provided a mechanistic basis for the therapeutic target in SSHTN and hypertensive kidney injury.
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Hipertensão , Inflamassomos , Camundongos , Animais , Inflamassomos/metabolismo , Proteína 3 que Contém Domínio de Pirina da Família NLR/genética , Proteína 3 que Contém Domínio de Pirina da Família NLR/metabolismo , Proteínas Quinases Ativadas por AMP/metabolismo , AutofagiaRESUMO
The spread of pathological α-synuclein (α-syn) is a crucial event in the progression of Parkinson's disease (PD). Cell surface receptors such as lymphocyte activation gene 3 (LAG3) and amyloid precursor-like protein 1 (APLP1) can preferentially bind α-syn in the amyloid over monomeric state to initiate cell-to-cell transmission. However, the molecular mechanism underlying this selective binding is unknown. Here, we perform an array of biophysical experiments and reveal that LAG3 D1 and APLP1 E1 domains commonly use an alkaline surface to bind the acidic C terminus, especially residues 118 to 140, of α-syn. The formation of amyloid fibrils not only can disrupt the intramolecular interactions between the C terminus and the amyloid-forming core of α-syn but can also condense the C terminus on fibril surface, which remarkably increase the binding affinity of α-syn to the receptors. Based on this mechanism, we find that phosphorylation at serine 129 (pS129), a hallmark modification of pathological α-syn, can further enhance the interaction between α-syn fibrils and the receptors. This finding is further confirmed by the higher efficiency of pS129 fibrils in cellular internalization, seeding, and inducing PD-like α-syn pathology in transgenic mice. Our work illuminates the mechanistic understanding on the spread of pathological α-syn and provides structural information for therapeutic targeting on the interaction of α-syn fibrils and receptors as a potential treatment for PD.
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Precursor de Proteína beta-Amiloide/metabolismo , Amiloide/metabolismo , Antígenos CD/metabolismo , Doença de Parkinson/metabolismo , Doença de Parkinson/patologia , alfa-Sinucleína/metabolismo , Animais , Linhagem Celular Tumoral , Endocitose , Humanos , Camundongos , Degeneração Neural/patologia , Neurônios/metabolismo , Fosforilação , Fosfosserina/metabolismo , Ligação Proteica , Eletricidade Estática , alfa-Sinucleína/química , alfa-Sinucleína/toxicidade , Proteína do Gene 3 de Ativação de LinfócitosRESUMO
The echo state network (ESN) is a recurrent neural network that has yielded state-of-the-art results in many areas owing to its rapid learning ability and the fact that the weights of input neurons and hidden neurons are fixed throughout the learning process. However, the setting procedure for initializing the ESN's recurrent structure may lead to difficulties in designing a sound reservoir that matches a specific task. This paper proposes an improved pre-training method to adjust the model's parameters and topology to obtain an adaptive reservoir for a given application. Two strategies, namely global random selection and ensemble training, are introduced to pre-train the randomly initialized ESN model. Specifically, particle swarm optimization is applied to optimize chosen fixed and global weight values within the network, and the reliability and stability of the pre-trained model are enhanced by employing the ensemble training strategy. In addition, we test the feasibility of the model for time series prediction on six benchmarks and two real-life datasets. The experimental results show a clear enhancement in the ESN learning results. Furthermore, the proposed global random selection and ensemble training strategies are also applied to pre-train the extreme learning machine (ELM), which has a similar training process to the ESN model. Numerical experiments are subsequently carried out on the above-mentioned eight datasets. The experimental findings consistently show that the performance of the proposed pre-trained ELM model is also improved significantly. The suggested two strategies can thus enhance the ESN and ELM models' prediction accuracy and adaptability.
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Lightweight and impact-resistant materials with self-monitoring capability are highly desired for protective applications, but are challenging to be artificially fabricated. Herein, a scalable-manufactured aramid nanofiber (ANF)-based composite combining these key properties is presented. Inspired by the strengthening and toughening mechanisms relying on recoverable interfaces commonly existing in biological composites, mechanically weak but dense hydrogen bonds are introduced into the ANF interfaces to achieve simultaneously enhanced tensile strength (300 MPa), toughness (55 MJ m-3 ), and impact resistance of the nanofibrous composite. The achieved mechanical property combination displays attractive advantages compared with that of most of previously reported nanocomposites. Additionally, the nanofibrous composite is designed with a capability for real-time self-monitoring of its structural safety during both quasi-static tensile and dynamic impact processes, based on the strain/damage-induced resistance variations of a conductive nanowire network inside it. These comprehensive properties enable the present nanofibrous composite with promising potential for protective applications.
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Nanofibras , Nanofibras/química , Resistência à TraçãoRESUMO
Direct, amplification-free detection of RNA has the potential to transform molecular diagnostics by enabling simple on-site analysis of human or environmental samples. CRISPR-Cas nucleases offer programmable RNA-guided RNA recognition that triggers cleavage and release of a fluorescent reporter molecule, but long reaction times hamper their detection sensitivity and speed. Here, we show that unrelated CRISPR nucleases can be deployed in tandem to provide both direct RNA sensing and rapid signal generation, thus enabling robust detection of ~30 molecules per µl of RNA in 20 min. Combining RNA-guided Cas13 and Csm6 with a chemically stabilized activator creates a one-step assay that can detect severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) RNA extracted from respiratory swab samples with quantitative reverse transcriptase PCR (qRT-PCR)-derived cycle threshold (Ct) values up to 33, using a compact detector. This Fast Integrated Nuclease Detection In Tandem (FIND-IT) approach enables sensitive, direct RNA detection in a format that is amenable to point-of-care infection diagnosis as well as to a wide range of other diagnostic or research applications.
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COVID-19/genética , Sistemas CRISPR-Cas/genética , RNA Viral/genética , SARS-CoV-2/genética , Humanos , Reação em Cadeia da Polimerase Via Transcriptase ReversaRESUMO
Posttranslational modifications (PTMs) of α-synuclein (α-syn), e.g., phosphorylation, play an important role in modulating α-syn pathology in Parkinson's disease (PD) and α-synucleinopathies. Accumulation of phosphorylated α-syn fibrils in Lewy bodies and Lewy neurites is the histological hallmark of these diseases. However, it is unclear how phosphorylation relates to α-syn pathology. Here, by combining chemical synthesis and bacterial expression, we obtained homogeneous α-syn fibrils with site-specific phosphorylation at Y39, which exhibits enhanced neuronal pathology in rat primary cortical neurons. We determined the cryo-electron microscopy (cryo-EM) structure of the pY39 α-syn fibril, which reveals a fold of α-syn with pY39 in the center of the fibril core forming an electrostatic interaction network with eight charged residues in the N-terminal region of α-syn. This structure composed of residues 1 to 100 represents the largest α-syn fibril core determined so far. This work provides structural understanding on the pathology of the pY39 α-syn fibril and highlights the importance of PTMs in defining the polymorphism and pathology of amyloid fibrils in neurodegenerative diseases.
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Doença de Parkinson , alfa-Sinucleína/química , Amiloide/química , Amiloide/metabolismo , Animais , Células Cultivadas , Microscopia Crioeletrônica , Regulação da Expressão Gênica/efeitos dos fármacos , Humanos , Modelos Moleculares , Neurônios/efeitos dos fármacos , Neurônios/metabolismo , Fosforilação , Conformação Proteica , Ratos , Ratos Sprague-Dawley , alfa-Sinucleína/síntese química , alfa-Sinucleína/metabolismoRESUMO
Strain in two-dimensional (2D) materials has attracted particular attention because of the remarkable modification of electronic and optical properties. However, emergent electromechanical phenomena and hidden mechanisms, such as strain-superlattice-induced topological states or flexoelectricity under strain gradient, remain under debate. Here, using scanning photocurrent microscopy, we observe significant photocurrent enhancement in hybrid vertical junction devices made of strained few-layer graphene and InGaN quantum dots. Optoelectronic response and photoluminescence measurements demonstrate a possible mechanism closely tied to the flexoelectric effect in few-layer graphene, where the strain can induce a lateral built-in electric field and assist the separation of electron-hole pairs. Photocurrent mapping reveals an unprecedentedly ordered hexagonal network, suggesting the potential to create a superlattice by strain engineering. Our work provides insights into optoelectronic phenomena in the presence of strain and paves the way for practical applications associated with strained 2D materials.
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Chronic exposure to stress is associated with increased incidence of depression, generalized anxiety, and PTSD. However, stress induces vulnerability to such disorders only in a sub-population of individuals, as others remain resilient. Inflammation has emerged as a putative mechanism for promoting stress vulnerability. Using a rodent model of social defeat, we have previously shown that rats with short-defeat latencies (SL/vulnerable rats) show increased anxiety- and depression-like behaviors, and these behaviors are mediated by inflammation in the ventral hippocampus. The other half of socially defeated rats show long-latencies to defeat (LL/resilient) and are similar to controls. Because gut microbiota are important activators of inflammatory substances, we assessed the role of the gut microbiome in mediating vulnerability to repeated social defeat stress. We analyzed the fecal microbiome of control, SL/vulnerable, and LL/resilient rats using shotgun metagenome sequencing and observed increased expression of immune-modulating microbiota, such as Clostridia, in SL/vulnerable rats. We then tested the importance of gut microbiota to the SL/vulnerable phenotype. In otherwise naive rats treated with microbiota from SL/vulnerable rats, there was higher microglial density and IL-1ß expression in the vHPC, and higher depression-like behaviors relative to rats that received microbiota from LL/resilient rats, non-stressed control rats, or vehicle-treated rats. However, anxiety-like behavior during social interaction was not altered by transplant of the microbiome of SL/vulnerable rats into non-stressed rats. Taken together, the results suggest the gut microbiome contributes to the depression-like behavior and inflammatory processes in the vHPC of stress vulnerable individuals.
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Microbioma Gastrointestinal , Animais , Ansiedade , Comportamento Animal , Depressão , Hipocampo , Ratos , Estresse PsicológicoRESUMO
OBJECTIVES: To enable non-invasive real-time quantification of vasopressin 1A (V1A) receptors in peripheral organs, we sought to develop a suitable PET probe that would allow specific and selective V1A receptor imaging in vitro and in vivo. METHODS: We synthesized a high-affinity and -selectivity ligand, designated compound 17. The target structure was labeled with carbon-11 and tested for its utility as a V1A-targeted PET tracer by cell uptake studies, autoradiography, in vivo PET imaging and ex vivo biodistribution experiments. RESULTS: Compound 17 (PF-184563) and the respective precursor for radiolabeling were synthesized in an overall yield of 49% (over 7 steps) and 40% (over 8 steps), respectively. An inhibitory constant of 0.9 nM towards the V1A receptors was measured, while excellent selectivity over the related V1B, V2 and OT receptor (IC50 >10,000 nM) were obtained. Cell uptake studies revealed considerable V1A binding, which was significantly reduced in the presence of V1A antagonists. Conversely, there was no significant blockade in the presence of V1B and V2 antagonists. In vitro autoradiography and PET imaging studies in rodents indicated specific tracer binding mainly in the liver. Further, the pancreas, spleen and the heart exhibited specific binding of [11C]17 ([11C]PF-184563) by ex vivo biodistribution experiments. CONCLUSION: We have developed the first V1A-targeted PET ligand that is suitable for subtype-selective receptor imaging in peripheral organs including the liver, heart, pancreas and spleen. Our findings suggest that [11C]PF-184563 can be a valuable tool to study the role of V1A receptors in liver diseases, as well as in cardiovascular pathologies.