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1.
PLoS Pathog ; 18(5): e1010437, 2022 05.
Artigo em Inglês | MEDLINE | ID: mdl-35587470

RESUMO

Herpes simplex virus (HSV) causes chronic infection in the human host, characterized by self-limited episodes of mucosal shedding and lesional disease, with latent infection of neuronal ganglia. The epidemiology of genital herpes has undergone a significant transformation over the past two decades, with the emergence of HSV-1 as a leading cause of first-episode genital herpes in many countries. Though dsDNA viruses are not expected to mutate quickly, it is not yet known to what degree the HSV-1 viral population in a natural host adapts over time, or how often viral population variants are transmitted between hosts. This study provides a comparative genomics analysis for 33 temporally-sampled oral and genital HSV-1 genomes derived from five adult sexual transmission pairs. We found that transmission pairs harbored consensus-level viral genomes with near-complete conservation of nucleotide identity. Examination of within-host minor variants in the viral population revealed both shared and unique patterns of genetic diversity between partners, and between anatomical niches. Additionally, genetic drift was detected from spatiotemporally separated samples in as little as three days. These data expand our prior understanding of the complex interaction between HSV-1 genomics and population dynamics after transmission to new infected persons.


Assuntos
Herpes Genital , Herpes Simples , Herpesvirus Humano 1 , Adulto , Genitália , Genômica , Herpes Simples/epidemiologia , Herpesvirus Humano 1/genética , Herpesvirus Humano 2/genética , Humanos
2.
J Gen Virol ; 103(10)2022 10.
Artigo em Inglês | MEDLINE | ID: mdl-36264606

RESUMO

Herpes simplex virus 1 (HSV1) is best known for causing oral lesions and mild clinical symptoms, but it can produce a significant range of disease severities and rates of reactivation. To better understand this phenotypic variation, we characterized 11 HSV1 strains that were isolated from individuals with diverse infection outcomes. We provide new data on genomic and in vitro plaque phenotype analysis for these isolates and compare these data to previously reported quantitation of the disease phenotype of each strain in a murine animal model. We show that integration of these three types of data permitted clustering of these HSV1 strains into four groups that were not distinguishable by any single dataset alone, highlighting the benefits of combinatorial multi-parameter phenotyping. Two strains (group 1) produced a partially or largely syncytial plaque phenotype and attenuated disease phenotypes in mice. Three strains of intermediate plaque size, causing severe disease in mice, were genetically clustered to a second group (group 2). Six strains with the smallest average plaque sizes were separated into two subgroups (groups 3 and 4) based on their different genetic clustering and disease severity in mice. Comparative genomics and network graph analysis suggested a separation of HSV1 isolates with attenuated vs. virulent phenotypes. These observations imply that virulence phenotypes of these strains may be traceable to genetic variation within the HSV1 population.


Assuntos
Herpes Simples , Herpesvirus Humano 1 , Camundongos , Animais , Herpesvirus Humano 1/genética , Fenótipo , Modelos Animais de Doenças , Genômica
3.
Molecules ; 28(1)2022 Dec 30.
Artigo em Inglês | MEDLINE | ID: mdl-36615506

RESUMO

The current approach to equine anti-doping is focused on the targeted detection of prohibited substances. However, as new substances are rapidly being developed, the need for complimentary methods for monitoring is crucial to ensure the integrity of the racing industry is upheld. Lipidomics is a growing field involved in the characterisation of lipids, their function and metabolism in a biological system. Different lipids have various biological effects throughout the equine system including platelet aggregation and inflammation. A certain class of lipids that are being reviewed are the eicosanoids (inflammatory markers). The use of eicosanoids as a complementary method for monitoring has become increasingly popular with various studies completed to highlight their potential. Studies including various corticosteroids, non-steroidal anti-inflammatories and cannabidiol have been reviewed to highlight the progress lipidomics has had in contributing to the equine anti-doping industry. This review has explored the techniques used to prepare and analyse samples for lipidomic investigations in addition to the statistical analysis and potential for lipidomics to be used for a longitudinal assessment in the equine anti-doping industry.


Assuntos
Inflamação , Lipidômica , Animais , Cavalos , Lipídeos , Biomarcadores , Eicosanoides , Metabolismo dos Lipídeos
4.
J Virol ; 93(8)2019 04 15.
Artigo em Inglês | MEDLINE | ID: mdl-30760568

RESUMO

A majority of adults in Finland are seropositive carriers of herpes simplex viruses (HSV). Infection occurs at epithelial or mucosal surfaces, after which virions enter innervating nerve endings, eventually establishing lifelong infection in neurons of the sensory or autonomic nervous system. Recent data have highlighted the genetic diversity of HSV-1 strains and demonstrated apparent geographic patterns in strain similarity. Though multiple HSV-1 genomes have been sequenced from Europe to date, there is a lack of sequenced genomes from the Nordic countries. Finland's history includes at least two major waves of human migration, suggesting the potential for diverse viruses to persist in the population. Here, we used HSV-1 clinical isolates from Finland to test the relationship between viral phylogeny, genetic variation, and phenotypic characteristics. We found that Finnish HSV-1 isolates separated into two distinct phylogenetic groups, potentially reflecting historical waves of human (and viral) migration into Finland. Each HSV-1 isolate harbored a distinct set of phenotypes in cell culture, including differences in the amount of virus production, extracellular virus release, and cell-type-specific fitness. Importantly, the phylogenetic clusters were not predictive of any detectable pattern in phenotypic differences, demonstrating that whole-genome relatedness is not a proxy for overall viral phenotype. Instead, we highlight specific gene-level differences that may contribute to observed phenotypic differences, and we note that strains from different phylogenetic groups can contain the same genetic variations.IMPORTANCE Herpes simplex viruses (HSV) infect a majority of adults. Recent data have highlighted the genetic diversity of HSV-1 strains and demonstrated apparent genomic relatedness between strains from the same geographic regions. We used HSV-1 clinical isolates from Finland to test the relationship between viral genomic and geographic relationships, differences in specific genes, and characteristics of viral infection. We found that viral isolates from Finland separated into two distinct groups of genomic and geographic relatedness, potentially reflecting historical patterns of human and viral migration into Finland. These Finnish HSV-1 isolates had distinct infection characteristics in multiple cell types tested, which were specific to each isolate and did not group according to genomic and geographic relatedness. This demonstrates that HSV-1 strain differences in specific characteristics of infection are set by a combination of host cell type and specific viral gene-level differences.


Assuntos
Variação Genética , Genoma Viral , Herpes Simples/genética , Herpesvirus Humano 1/genética , Filogenia , Animais , Chlorocebus aethiops , Feminino , Finlândia , Herpesvirus Humano 1/isolamento & purificação , Humanos , Masculino , Células Vero , Sequenciamento Completo do Genoma
5.
Nat Chem Biol ; 12(5): 339-44, 2016 May.
Artigo em Inglês | MEDLINE | ID: mdl-26999780

RESUMO

Biosynthesis enables renewable production of manifold compounds, yet often biosynthetic performance must be improved for it to be economically feasible. Nongenetic, cell-to-cell variations in protein and metabolite concentrations are naturally inherent, suggesting the existence of both high- and low-performance variants in all cultures. Although having an intrinsic source of low performers might cause suboptimal ensemble biosynthesis, the existence of high performers suggests an avenue for performance enhancement. Here we develop in vivo population quality control (PopQC) to continuously select for high-performing, nongenetic variants. We apply PopQC to two biosynthetic pathways using two alternative design principles and demonstrate threefold enhanced production of both free fatty acid (FFA) and tyrosine. We confirm that PopQC improves ensemble biosynthesis by selecting for nongenetic high performers. Additionally, we use PopQC in fed-batch FFA production and achieve 21.5 g l(-1) titer and 0.5 g l(-1) h(-1) productivity. Given the ubiquity of nongenetic variation, PopQC should be applicable to a variety of metabolic pathways for enhanced biosynthesis.


Assuntos
Escherichia coli/citologia , Escherichia coli/fisiologia , Ácidos Graxos não Esterificados/biossíntese , Tirosina/biossíntese , Clonagem Molecular , Regulação Bacteriana da Expressão Gênica , Engenharia Metabólica , Redes e Vias Metabólicas
6.
Biomacromolecules ; 19(9): 3853-3860, 2018 09 10.
Artigo em Inglês | MEDLINE | ID: mdl-30080972

RESUMO

Despite significant efforts to engineer their heterologous production, recombinant spider silk proteins (spidroins) have yet to replicate the unparalleled combination of high strength and toughness exhibited by natural spider silks, preventing their use in numerous mechanically demanding applications. To overcome this long-standing challenge, we have developed a synthetic biology approach combining standardized DNA part assembly and split intein-mediated ligation to produce recombinant spidroins of previously unobtainable size (556 kDa), containing 192 repeat motifs of the Nephila clavipes dragline spidroin. Fibers spun from our synthetic spidroins are the first to fully replicate the mechanical performance of their natural counterparts by all common metrics, i.e., tensile strength (1.03 ± 0.11 GPa), modulus (13.7 ± 3.0 GPa), extensibility (18 ± 6%), and toughness (114 ± 51 MJ/m3). The developed process reveals a path to more dependable production of high-performance silks for mechanically demanding applications while also providing a platform to facilitate production of other high-performance natural materials.


Assuntos
Fibroínas/química , Resistência à Tração , Elasticidade , Fibroínas/genética , Fibroínas/normas , Proteínas Recombinantes/química , Proteínas Recombinantes/genética
7.
Macromol Rapid Commun ; 39(18): e1800340, 2018 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-30073709

RESUMO

Dielectric elastomers have the capability to be used as transducers for actuation and energy harvesting applications due to their excellent combination of large strain capability (100-400%), rapid response (10-3  s), high energy density (10-150 kJ m-3 ), low noise, and lightweight nature. However, the dielectric properties of non-polar elastomers such as dielectric permittivity εr , breakdown strength Eb , and dielectric loss ε ″, need to be enhanced for real world applications. The introduction of polar groups or structures into dielectric elastomers through covalently bonding is an attractive approach to 'intrinsically' induce a permanent polarity to the elastomers, and can eliminate the poor post-processing issues and breakdown strength of extrinsically modified materials, which have often been prepared by incorporation of fillers. This review discusses the chemical methods for modification of dielectric elastomers, such as hydrosilylation, thiol-ene click chemistry, azide click chemistry, and atom transfer radical polymerization. The effects of the type and concentration of polar groups on the dielectric and mechanical properties of the elastomers and their performance in actuation and harvesting systems are discussed. State-of-the-art developments and perspectives of modified dielectric elastomers for deformable energy generators and transducers are provided.


Assuntos
Polímeros/química , Azidas/química , Química Click , Elasticidade , Elastômeros , Eletrônica , Radicais Livres/síntese química , Radicais Livres/química , Fenômenos Mecânicos , Compostos de Sulfidrila/química
8.
Chemistry ; 22(2): 546-9, 2016 Jan 11.
Artigo em Inglês | MEDLINE | ID: mdl-26493538

RESUMO

Dispersions of single-walled carbon nanotubes (SWNTs) have been prepared by using the room-temperature ionic liquid [BMIM][BF4 ] (1-butyl-3-methylimidazolium tetrafluoroborate), the triblock copolymer Pluronic L121 [poly(ethylene oxide)5 -poly(propylene oxide)68 -poly(ethylene oxide)5 ] and the non-ionic surfactant Triton X-100 (TX100) in the pure state. The size of the SWNTs aggregates and the dispersion degree in the three viscous systems depend on the sonication time, as highlighted by UV/Vis/NIR spectroscopy and optical microscopy analysis. A nonlinear increase in conductivity can be observed as a function of the SWNTs loading, as suggested by electrochemical impedance spectroscopy. The generation of a three-dimensional network of SWNTs showing a viscoelastic gel-like behavior above a critical percolation concentration has been found at 25 °C in all the investigated systems by oscillatory rheology measurements.

9.
Sci Technol Adv Mater ; 17(1): 769-776, 2016.
Artigo em Inglês | MEDLINE | ID: mdl-27933117

RESUMO

This work demonstrates the potential of porous BaTiO3 for piezoelectric sensor and energy-harvesting applications by manufacture of materials, detailed characterisation and application of new models. Ferroelectric macro-porous BaTiO3 ceramics for piezoelectric applications are manufactured for a range of relative densities, α = 0.30-0.95, using the burned out polymer spheres method. The piezoelectric activity and relevant parameters for specific applications are interpreted by developing two models: a model of a 3-0 composite and a 'composite in composite' model. The appropriate ranges of relative density for the application of these models to accurately predict piezoelectric properties are examined. The two models are extended to take into account the effect of 90° domain-wall mobility within ceramic grains on the piezoelectric coefficients [Formula: see text]. It is shown that porous ferroelectrics provide a novel route to form materials with large piezoelectric anisotropy [Formula: see text] at 0.20 ≤ α ≤ 0.45 and achieve a high squared figure of merit [Formula: see text] [Formula: see text]. The modelling approach allows a detailed analysis of the relationships between the properties of the monolithic and porous materials for the design of porous structures with optimum properties.

10.
J Biol Chem ; 288(24): 17261-71, 2013 Jun 14.
Artigo em Inglês | MEDLINE | ID: mdl-23649619

RESUMO

Reoviruses are double-stranded RNA viruses that infect the mammalian respiratory and gastrointestinal tract. Reovirus infection elicits production of type I interferons (IFNs), which trigger antiviral pathways through the induction of interferon-stimulated genes (ISGs). Although hundreds of ISGs have been identified, the functions of many of these genes are unknown. The interferon-inducible transmembrane (IFITM) proteins are one class of ISGs that restrict the cell entry of some enveloped viruses, including influenza A virus. One family member, IFITM3, localizes to late endosomes, where reoviruses undergo proteolytic disassembly; therefore, we sought to determine whether IFITM3 also restricts reovirus entry. IFITM3-expressing cell lines were less susceptible to infection by reovirus, as they exhibited significantly lower percentages of infected cells in comparison to control cells. Reovirus replication was also significantly reduced in IFITM3-expressing cells. Additionally, cells expressing an shRNA targeting IFITM3 exhibited a smaller decrease in infection after IFN treatment than the control cells, indicating that endogenous IFITM3 restricts reovirus infection. However, IFITM3 did not restrict entry of reovirus infectious subvirion particles (ISVPs), which do not require endosomal proteolysis, indicating that restriction occurs in the endocytic pathway. Proteolysis of outer capsid protein µ1 was delayed in IFITM3-expressing cells in comparison to control cells, suggesting that IFITM3 modulates the function of late endosomal compartments either by reducing the activity of endosomal proteases or delaying the proteolytic processing of virions. These data provide the first evidence that IFITM3 restricts infection by a nonenveloped virus and suggest that IFITM3 targets an increasing number of viruses through a shared requirement for endosomes during cell entry.


Assuntos
Orthoreovirus Mamífero 3/fisiologia , Proteínas de Membrana/fisiologia , Proteínas de Ligação a RNA/fisiologia , Internalização do Vírus , Capsídeo/metabolismo , Endocitose , Endossomos/virologia , Expressão Gênica , Técnicas de Silenciamento de Genes , Células HeLa , Interações Hospedeiro-Patógeno , Humanos , Interferon-alfa/fisiologia , Cinética , Orthoreovirus de Mamíferos/fisiologia , RNA Interferente Pequeno/genética , Vírion/fisiologia , Montagem de Vírus , Replicação Viral
11.
Plant Cell ; 23(9): 3374-91, 2011 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-21949153

RESUMO

Receptors localized at the plasma membrane are critical for the recognition of pathogens. The molecular determinants that regulate receptor transport to the plasma membrane are poorly understood. In a screen for proteins that interact with the FLAGELIN-SENSITIVE2 (FLS2) receptor using Arabidopsis thaliana protein microarrays, we identified the reticulon-like protein RTNLB1. We showed that FLS2 interacts in vivo with both RTNLB1 and its homolog RTNLB2 and that a Ser-rich region in the N-terminal tail of RTNLB1 is critical for the interaction with FLS2. Transgenic plants that lack RTNLB1 and RTNLB2 (rtnlb1 rtnlb2) or overexpress RTNLB1 (RTNLB1ox) exhibit reduced activation of FLS2-dependent signaling and increased susceptibility to pathogens. In both rtnlb1 rtnlb2 and RTNLB1ox, FLS2 accumulation at the plasma membrane was significantly affected compared with the wild type. Transient overexpression of RTNLB1 led to FLS2 retention in the endoplasmic reticulum (ER) and affected FLS2 glycosylation but not FLS2 stability. Removal of the critical N-terminal Ser-rich region or either of the two Tyr-dependent sorting motifs from RTNLB1 causes partial reversion of the negative effects of excess RTNLB1 on FLS2 transport out of the ER and accumulation at the membrane. The results are consistent with a model whereby RTNLB1 and RTNLB2 regulate the transport of newly synthesized FLS2 to the plasma membrane.


Assuntos
Proteínas de Arabidopsis/metabolismo , Arabidopsis/genética , Proteínas Quinases/metabolismo , Receptores Imunológicos/metabolismo , Arabidopsis/imunologia , Arabidopsis/metabolismo , Proteínas de Arabidopsis/genética , Retículo Endoplasmático/metabolismo , Regulação da Expressão Gênica de Plantas , Glicosilação , Plantas Geneticamente Modificadas/genética , Plantas Geneticamente Modificadas/imunologia , Plantas Geneticamente Modificadas/metabolismo , Análise Serial de Proteínas , Domínios e Motivos de Interação entre Proteínas , Proteínas Quinases/genética , Sinais Direcionadores de Proteínas , Transporte Proteico , Receptores Imunológicos/genética
12.
Pharm Res ; 30(6): 1652-62, 2013 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-23462934

RESUMO

PURPOSE: To investigate whether permeation enhancement techniques affect the nail plate. METHODS: Infrared and impedance spectroscopies examined the effects of hydration, iontophoresis and N-acetyl-L-cysteine on the human nail. RESULTS: While significant shifts to higher wavenumbers were observed for the symmetric and asymmetric -CH2 stretching vibrations these changes were essentially the same for the three treatments suggesting they were principally due to hydration alone. Spectral changes associated with amide bonds from nail protein were particularly evident post-treatment with N-acetyl-L-cysteine. The alternating current conductivity and permittivity of the nail, particularly at low frequencies, increased with hydration. Iontophoresis increased the low frequency ac conductivity of the nail but had less effect on the nail capacitance/permittivity. Further, the effects seemed to return gradually to baseline after termination of current passage. Treatment with N-acetyl-L-cysteine produced a greater perturbation, leading to increased low-frequency conductivity and a shift of the frequency-dependent conductivity region to a higher frequency. CONCLUSIONS: Overall, the effects of iontophoresis on infrared and impedance spectroscopic profiles of the nail were attributable simply to increased hydration and similar to those observed after skin iontophoresis. In contrast, both spectroscopy techniques indicated that N-acetyl-L-cysteine disrupted nail structure in line with the enhancer's known effect on keratin.


Assuntos
Espectroscopia Dielétrica/métodos , Iontoforese/métodos , Unhas/metabolismo , Espectrofotometria Infravermelho/métodos , Acetilcisteína/administração & dosagem , Humanos , Queratinas/metabolismo , Permeabilidade/efeitos dos fármacos , Pele/metabolismo
13.
Drug Test Anal ; 14(5): 943-952, 2022 May.
Artigo em Inglês | MEDLINE | ID: mdl-35195373

RESUMO

The conventional detection of exogenous drugs in equine doping samples has been used for confirmation and subsequent prosecution of participants responsible. In recent years, alternative methods using indirect detection have been investigated due to the expanding number of pharmaceutical agents available with the potential of misuse. The monitoring of endogenous biomarkers such as hydrocortisone (HC) has been studied in equine urine with an international threshold of 1 µg/ml established; however, there is no current threshold for equine plasma. The aim of this research was to investigate plasma concentrations of HC and cortisone (C) in race day samples compared to an administration of Triamcinolone Acetonide (TACA). The reference population (n = 1150) provided HC (6 to 145 ng/ml) and C (0.7 to 13 ng/ml) levels to derive the HC to C ratio (HC/C). Population reference limits (PRLs) were proposed for HC/C values at 0.2 (lower) and 61 (upper). Administration of TACA resulted in down-regulation of HC/C values below the estimated PRLs for up to 96 h post-administration. This indirect detection period was longer than the detection of TACA for 72 h. The use of individual reference limits (IRLs) for HC/C values was investigated to support the Equine Biological Passport (EBP), an intelligence model developed by Racing NSW for longitudinal monitoring of biomarkers.


Assuntos
Cortisona , Dopagem Esportivo , Animais , Biomarcadores , Cromatografia Líquida de Alta Pressão/métodos , Cromatografia Líquida , Cavalos , Humanos , Hidrocortisona , Preparações Farmacêuticas , Espectrometria de Massas em Tandem/métodos
14.
Drug Test Anal ; 14(5): 936-942, 2022 May.
Artigo em Inglês | MEDLINE | ID: mdl-35343638

RESUMO

Equine urine analysis has evolved over time to detect thousands of urinary compounds for doping control in the horse racing industry. The longitudinal assessment of 3-methoxytyramine to tyramine ratio (3-MT/T) values in equine urine by GC-MS profiling was investigated to support the Racing NSW Equine Biological Passport (EBP) for detection of dopaminergic manipulation in racehorses. This involved comparison of routine urine samples to administration studies of Sinemet, a common Parkinson's disease medication containing levodopa. Using an endogenous reference compound (ERC) in a urinary ratio enabled greater confidence to provide intelligence of pharmaceutical manipulation as distinct from physiological variation. Population reference limits (PRLs) of 776 ng/ml for urinary 3-MT and 5.3 for 3-MT/T, together with the use of individual reference limits (IRLs), are proposed.


Assuntos
Dopagem Esportivo , Tiramina , Animais , Dopamina/análogos & derivados , Cavalos , Inteligência , Urinálise
15.
J Am Soc Mass Spectrom ; 33(7): 1276-1281, 2022 Jul 06.
Artigo em Inglês | MEDLINE | ID: mdl-35791638

RESUMO

The identification and confirmation of steroid sulfate metabolites in biological samples are essential to various fields, including anti-doping analysis and clinical sciences. Ultra-high-performance liquid chromatography with tandem mass spectrometry (UHPLC-MS/MS) is the leading method for the detection of intact steroid conjugates in biofluids, but because of the inherent complexity of biological samples and the low concentration of many targets of interest, metabolite identification based solely on mass spectrometry remains a major challenge. The confirmation of new metabolites typically depends on a comparison with synthetically derived reference materials that encompass a range of possible conjugation sites and stereochemistries. Herein, energy-resolved collision-induced dissociation (CID) is used as part of UHPLC-HRMS/MS analysis to distinguish between regio- and stereo-isomeric steroid sulfate compounds. This wholly MS-based approach was employed to guide the synthesis of reference materials to unambiguously confirm the identity of an equine steroid sulfate biomarker of testosterone propionate administration.


Assuntos
Esteroides , Espectrometria de Massas em Tandem , Animais , Biomarcadores , Cromatografia Líquida de Alta Pressão , Cavalos , Sulfatos
16.
Artigo em Inglês | MEDLINE | ID: mdl-35041603

RESUMO

Porous and composite piezoelectric ceramics are of interest for underwater ultrasonic transducers due to their improved voltage sensitivity and acoustic matching with water, compared with their dense counterparts. Commonly, these materials are fabricated by dice-and-fill of sintered blocks of polycrystalline piezoceramic, which results in a high volume of waste. The freeze-casting technique offers a low waste and scalable alternative to the dice-and-fill method to produce porous piezoceramics with highly orientated, anisometric pores. In this article, we have fabricated underwater ultrasonic transducers from freeze-cast lead zirconate titanate (PZT) with a range of porosities. The porous PZT samples were characterized in terms of their piezoelectric and dielectric properties before being encapsulated for acoustic performance testing in water. Off resonance, the on- axis receive sensitivity of the manufactured devices was approximately [Formula: see text]; the transmit voltage response (TVR) was in the range of approximately [Formula: see text] at 60 kHz to [Formula: see text] at 180 kHz. The most porous transducer devices (0.51, 0.43, and 0.33 pore fraction) exhibited primarily a thickness mode resonance, whereas the least porous transducers (0.29 pore fraction and dense benchmark) exhibited an undesired radial mode, which was observed as an additional resonant peak in the electrical impedance measurements and lateral off-axis lobes in the acoustic beampatterns. Our results show that the acoustic sensitivities and TVRs of the porous freeze-cast transducers are comparable to those of a dense pressed transducer. However, the freeze-cast transducers with porosity exceeding 0.30 pore fraction were shown to achieve an effective structure with aligned porosity that suppressed undesired radial mode resonances.


Assuntos
Transdutores , Ultrassom , Desenho de Equipamento , Porosidade , Ultrassonografia/métodos
17.
Nat Commun ; 13(1): 6865, 2022 11 11.
Artigo em Inglês | MEDLINE | ID: mdl-36369508

RESUMO

Suppression of dangerous or inappropriate reward-motivated behaviors is critical for survival, whereas therapeutic or recreational opioid use can unleash detrimental behavioral actions and addiction. Nevertheless, the neuronal systems that suppress maladaptive motivated behaviors remain unclear, and whether opioids disengage those systems is unknown. In a mouse model using two-photon calcium imaging in vivo, we identify paraventricular thalamostriatal neuronal ensembles that are inhibited upon sucrose self-administration and seeking, yet these neurons are tonically active when behavior is suppressed by a fear-provoking predator odor, a pharmacological stressor, or inhibitory learning. Electrophysiological, optogenetic, and chemogenetic experiments reveal that thalamostriatal neurons innervate accumbal parvalbumin interneurons through synapses enriched with calcium permeable AMPA receptors, and activity within this circuit is necessary and sufficient for the suppression of sucrose seeking regardless of the behavioral suppressor administered. Furthermore, systemic or intra-accumbal opioid injections rapidly dysregulate thalamostriatal ensemble dynamics, weaken thalamostriatal synaptic innervation of downstream neurons, and unleash reward-seeking behaviors in a manner that is reversed by genetic deletion of thalamic µ-opioid receptors. Overall, our findings reveal a thalamostriatal to parvalbumin interneuron circuit that is both required for the suppression of reward seeking and rapidly disengaged by opioids.


Assuntos
Analgésicos Opioides , Parvalbuminas , Camundongos , Animais , Analgésicos Opioides/farmacologia , Cálcio , Recompensa , Sacarose
18.
Biol Rhythm Res ; 42(2): 99-110, 2011 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-21686036

RESUMO

Sleep deprivation has a complex set of neurological effects that go beyond a mere slowing of mental processes. While cognitive and perceptual impairments in sleep deprived individuals are widespread, some abilities remain intact. In an effort to characterize these effects, some have suggested an impairment of complex decision making ability despite intact ability to follow simple rules. To examine this trade-off, 24-hour total sleep deprived individuals performed two versions of a resource acquisition foraging task, one in which exploration is optimal (to succeed, abandon low value, high saliency options) and another in which exploitation is optimal (to succeed, refrain from switching between options). Sleep deprived subjects exhibited decreased performance on the exploitation task compared to non-sleep deprived controls, yet both groups exhibited increased performance on the exploratory task. These results speak to previous neuropsychological work on cognitive control.

19.
Adv Mater ; 33(33): e2008052, 2021 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-34165832

RESUMO

Engineering materials and devices can be damaged during their service life as a result of mechanical fatigue, punctures, electrical breakdown, and electrochemical corrosion. This damage can lead to unexpected failure during operation, which requires regular inspection, repair, and replacement of the products, resulting in additional energy consumption and cost. During operation in challenging, extreme, or harsh environments, such as those encountered in high or low temperature, nuclear, offshore, space, and deep mining environments, the robustness and stability of materials and devices are extremely important. Over recent decades, significant effort has been invested into improving the robustness and stability of materials through either structural design, the introduction of new chemistry, or improved manufacturing processes. Inspired by natural systems, the creation of self-healing materials has the potential to overcome these challenges and provide a route to achieve dynamic repair during service. Current research on self-healing polymers remains in its infancy, and self-healing behavior under harsh and extreme conditions is a particularly untapped area of research. Here, the self-healing mechanisms and performance of materials under a variety of harsh environments are discussed. An overview of polymer-based devices developed for a range of challenging environments is provided, along with areas for future research.

20.
Nat Commun ; 12(1): 5182, 2021 08 30.
Artigo em Inglês | MEDLINE | ID: mdl-34462443

RESUMO

Manmade high-performance polymers are typically non-biodegradable and derived from petroleum feedstock through energy intensive processes involving toxic solvents and byproducts. While engineered microbes have been used for renewable production of many small molecules, direct microbial synthesis of high-performance polymeric materials remains a major challenge. Here we engineer microbial production of megadalton muscle titin polymers yielding high-performance fibers that not only recapture highly desirable properties of natural titin (i.e., high damping capacity and mechanical recovery) but also exhibit high strength, toughness, and damping energy - outperforming many synthetic and natural polymers. Structural analyses and molecular modeling suggest these properties derive from unique inter-chain crystallization of folded immunoglobulin-like domains that resists inter-chain slippage while permitting intra-chain unfolding. These fibers have potential applications in areas from biomedicine to textiles, and the developed approach, coupled with the structure-function insights, promises to accelerate further innovation in microbial production of high-performance materials.


Assuntos
Conectina/química , Conectina/genética , Escherichia coli/metabolismo , Fibras Musculares Esqueléticas/química , Animais , Fenômenos Biomecânicos , Conectina/metabolismo , Cristalização , Escherichia coli/genética , Expressão Gênica , Peso Molecular , Fibras Musculares Esqueléticas/metabolismo , Polimerização , Polímeros/química , Polímeros/metabolismo , Dobramento de Proteína , Coelhos
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