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1.
Cureus ; 16(3): e57107, 2024 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-38681425

RESUMO

In the maxillary anterior area, the esthetic integration of prosthetic restorations is a challenge, particularly for screw-retained implant prostheses. This case report presents the management and clinical outcome of an old partial edentulous maxillary jaw in an esthetic zone in a young patient with a very limited mouth opening. This patient was rehabilitated with an implant screw-retained fixed partial denture (FPD) using both digital and conventional techniques.

2.
Nucleic Acids Res ; 52(6): e30, 2024 Apr 12.
Artigo em Inglês | MEDLINE | ID: mdl-38346683

RESUMO

The CRISPR/Cas system has emerged as a powerful tool for genome editing in metabolic engineering and human gene therapy. However, locating the optimal site on the chromosome to integrate heterologous genes using the CRISPR/Cas system remains an open question. Selecting a suitable site for gene integration involves considering multiple complex criteria, including factors related to CRISPR/Cas-mediated integration, genetic stability, and gene expression. Consequently, identifying such sites on specific or different chromosomal locations typically requires extensive characterization efforts. To address these challenges, we have developed CRISPR-COPIES, a COmputational Pipeline for the Identification of CRISPR/Cas-facilitated intEgration Sites. This tool leverages ScaNN, a state-of-the-art model on the embedding-based nearest neighbor search for fast and accurate off-target search, and can identify genome-wide intergenic sites for most bacterial and fungal genomes within minutes. As a proof of concept, we utilized CRISPR-COPIES to characterize neutral integration sites in three diverse species: Saccharomyces cerevisiae, Cupriavidus necator, and HEK293T cells. In addition, we developed a user-friendly web interface for CRISPR-COPIES (https://biofoundry.web.illinois.edu/copies/). We anticipate that CRISPR-COPIES will serve as a valuable tool for targeted DNA integration and aid in the characterization of synthetic biology toolkits, enable rapid strain construction to produce valuable biochemicals, and support human gene and cell therapy applications.


Assuntos
Sistemas CRISPR-Cas , Biologia Computacional , Simulação por Computador , Edição de Genes , Humanos , Sistemas CRISPR-Cas/genética , Células HEK293 , Saccharomyces cerevisiae/genética , Biologia Computacional/métodos , Betaproteobacteria/genética , Interface Usuário-Computador
3.
Sci Total Environ ; 912: 168701, 2024 Feb 20.
Artigo em Inglês | MEDLINE | ID: mdl-37992833

RESUMO

The Argonaute protein from the archaeon Pyrococcus furiosus (PfAgo) is a DNA-guided nuclease that targets DNA with any sequence. We designed a virus detection assay in which the PfAgo enzyme cleaves the reporter probe, thus generating fluorescent signals when amplicons from a reverse transcriptase loop-mediated isothermal amplification (RT-LAMP) assay contain target sequences. We confirmed that the RT-LAMP-PfAgo assay for the SARS-CoV-2 Delta variant produced significantly higher fluorescent signals (p < 0.001) when a single nucleotide polymorphism (SNP), exclusive to the Delta variant, was present, compared to the samples without the SNP. Additionally, the duplex assay for Pepper mild mottle virus (PMMOV) and SARS-CoV-2 detection produced specific fluorescent signals (FAM or ROX) only when the corresponding sequences were present. Furthermore, the RT-LAMP-PfAgo assay does not require dilution to reduce the impact of environmental inhibitors. The limit of detection of the PMMOV assay, determined with 30 wastewater samples, was 28 gc/µL, with a 95 % confidence interval of [11,103]. Finally, using a point-of-use device, the RT-LAMP-PfAgo assay successfully detected PMMOV in wastewater samples. Based on our findings, we conclude that the RT-LAMP-PfAgo assay can be used as a portable, SNP-specific duplex assay, which will significantly improve virus surveillance in wastewater.


Assuntos
Polimorfismo de Nucleotídeo Único , Águas Residuárias , Sensibilidade e Especificidade , DNA
4.
Nat Commun ; 13(1): 2697, 2022 05 16.
Artigo em Inglês | MEDLINE | ID: mdl-35577775

RESUMO

Plasmids are used extensively in basic and applied biology. However, design and construction of plasmids, specifically the ones carrying complex genetic information, remains one of the most time-consuming, labor-intensive, and rate-limiting steps in performing sophisticated biological experiments. Here, we report the development of a versatile, robust, automated end-to-end platform named PlasmidMaker that allows error-free construction of plasmids with virtually any sequences in a high throughput manner. This platform consists of a most versatile DNA assembly method using Pyrococcus furiosus Argonaute (PfAgo)-based artificial restriction enzymes, a user-friendly frontend for plasmid design, and a backend that streamlines the workflow and integration with a robotic system. As a proof of concept, we used this platform to generate 101 plasmids from six different species ranging from 5 to 18 kb in size from up to 11 DNA fragments. PlasmidMaker should greatly expand the potential of synthetic biology.


Assuntos
DNA , Pyrococcus furiosus , DNA/genética , Enzimas de Restrição do DNA/genética , Plasmídeos/genética , Pyrococcus furiosus/genética , Biologia Sintética/métodos
5.
Neuroimage Clin ; 33: 102953, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-35139478

RESUMO

OBJECTIVE: The integration of somatosensory, ocular motor and vestibular signals is necessary for self-location in space and goal-directed action. We aimed to detect remote changes in the cerebral cortex after thalamic infarcts to reveal the thalamo-cortical connections necessary for multisensory processing and ocular motor control. METHODS: Thirteen patients with unilateral ischemic thalamic infarcts presenting with vestibular, somatosensory, and ocular motor symptoms were examined longitudinally in the acute phase and after six months. Voxel- and surface-based morphometry were used to detect changes in vestibular and multisensory cortical areas and known hubs of central ocular motor processing. The results were compared with functional connectivity data in 50 healthy volunteers. RESULTS: Patients with paramedian infarcts showed impaired saccades and vestibular perception, i.e., tilts of the subjective visual vertical (SVV). The most common complaint in these patients was double vision or vertigo / dizziness. Posterolateral thalamic infarcts led to tilts of the SVV and somatosensory deficits without vertigo. Tilts of the SVV were higher in paramedian compared to posterolateral infarcts (median 11.2° vs 3.8°). Vestibular and ocular motor symptoms recovered within six months. Somatosensory deficits persisted. Structural longitudinal imaging showed significant volume reduction in subcortical structures connected to the infarcted thalamic nuclei (vestibular nuclei region, dentate nucleus region, trigeminal root entry zone, medial lemniscus, superior colliculi). Volume loss was evident in connections to the frontal, parietal and cingulate lobes. Changes were larger in the ipsilesional hemisphere but were also detected in homotopical regions contralesionally. The white matter volume reduction led to deformation of the cortical projection zones of the infarcted nuclei. CONCLUSIONS: White matter volume loss after thalamic infarcts reflects sensory input from the brainstem as well the cortical projections of the main affected nuclei for sensory and ocular motor processing. Changes in the cortical geometry seem not to reflect gray matter atrophy but rather reshaping of the cortical surface due to the underlying white matter atrophy.


Assuntos
Vestíbulo do Labirinto , Substância Branca , Córtex Cerebral/diagnóstico por imagem , Infarto Cerebral/complicações , Infarto Cerebral/diagnóstico por imagem , Humanos , Tálamo/diagnóstico por imagem , Substância Branca/diagnóstico por imagem
6.
Eur J Neurol ; 29(5): 1514-1523, 2022 05.
Artigo em Inglês | MEDLINE | ID: mdl-35098611

RESUMO

BACKGROUND AND PURPOSE: We aimed to delineate common principles of reorganization after infarcts of the subcortical vestibular circuitry related to the clinical symptomatology. Our hypothesis was that the recovery of specific symptoms is associated with changes in distinct regions within the core vestibular, somatosensory, and visual cortical and subcortical networks. METHODS: We used voxel- and surface-based morphometry to investigate structural reorganization of subcortical and cortical brain areas in 42 patients with a unilateral, subcortical infarct with vestibular and ocular motor deficits in the acute phase. The patients received structural neuroimaging and clinical monitoring twice (acute phase and after 6 months) to detect within-subject changes over time. RESULTS: In patients with vestibular signs such as tilts of the subjective visual vertical (SVV) and ocular torsion in the acute phase, significant volumetric increases in the superficial white matter around the parieto-opercular (retro-)insular vestibular cortex (PIVC) were found at follow-up. In patients with SVV tilts, spontaneous nystagmus, and rotatory vertigo in the acute phase, gray matter volume decreases were located in the cerebellum and the visual cortex bilaterally at follow-up. Patients with saccade pathology demonstrated volumetric decreases in cerebellar, thalamic, and cortical centers for ocular motor control. CONCLUSIONS: The findings support the role of the PIVC as the key hub for vestibular processing and reorganization. The volumetric decreases represent the reciprocal interaction of the vestibular, visual, and ocular motor systems during self-location and egomotion detection. A modulation in vestibular and ocular motor as well as visual networks was induced independently of the vestibular lesion site.


Assuntos
Vestíbulo do Labirinto , Substância Branca , Encéfalo/patologia , Córtex Cerebral , Infarto Cerebral/patologia , Humanos , Vertigem
7.
Astrophys J Lett ; 907(2)2021 Feb 01.
Artigo em Inglês | MEDLINE | ID: mdl-33959247

RESUMO

Cluster analysis of presolar silicon carbide grains based on literature data for 12C/13C, 14N/15N, δ 30Si/28Si, and δ 29Si/28Si including or not inferred initial 26Al/27Al data, reveals nine clusters agreeing with previously defined grain types but also highlighting new divisions. Mainstream grains reside in three clusters probably representing different parent star metallicities. One of these clusters has a compact core, with a narrow range of composition, pointing to an enhanced production of SiC grains in asymptotic giant branch (AGB) stars with a narrow range of masses and metallicities. The addition of 26Al/27Al data highlights a cluster of mainstream grains, enriched in 15N and 26Al, which cannot be explained by current AGB models. We defined two AB grain clusters, one with 15N and 26Al excesses, and the other with 14N and smaller 26Al excesses, in agreement with recent studies. Their definition does not use the solar N isotopic ratio as a divider, and the contour of the 26Al-rich AB cluster identified in this study is in better agreement with core-collapse supernova models. We also found a cluster with a mixture of putative nova and AB grains, which may have formed in supernova or nova environments. X grains make up two clusters, having either strongly correlated Si isotopic ratios or deviating from the 2/3 slope line in the Si 3-isotope plot. Finally, most Y and Z grains are jointly clustered, suggesting that the previous use of 12C/13C = 100 as a divider for Y grains was arbitrary. Our results show that cluster analysis is a powerful tool to interpret the data in light of stellar evolution and nucleosynthesis modeling and highlight the need of more multi-element isotopic data for better classification.

8.
Nat Commun ; 12(1): 2905, 2021 05 18.
Artigo em Inglês | MEDLINE | ID: mdl-34006857

RESUMO

The need for rapid, accurate, and scalable testing systems for COVID-19 diagnosis is clear and urgent. Here, we report a rapid Scalable and Portable Testing (SPOT) system consisting of a rapid, highly sensitive, and accurate assay and a battery-powered portable device for COVID-19 diagnosis. The SPOT assay comprises a one-pot reverse transcriptase-loop-mediated isothermal amplification (RT-LAMP) followed by PfAgo-based target sequence detection. It is capable of detecting the N gene and E gene in a multiplexed reaction with the limit of detection (LoD) of 0.44 copies/µL and 1.09 copies/µL, respectively, in SARS-CoV-2 virus-spiked saliva samples within 30 min. Moreover, the SPOT system is used to analyze 104 clinical saliva samples and identified 28/30 (93.3% sensitivity) SARS-CoV-2 positive samples (100% sensitivity if LoD is considered) and 73/74 (98.6% specificity) SARS-CoV-2 negative samples. This combination of speed, accuracy, sensitivity, and portability will enable high-volume, low-cost access to areas in need of urgent COVID-19 testing capabilities.


Assuntos
Teste de Ácido Nucleico para COVID-19 , COVID-19/diagnóstico , Sistemas Automatizados de Assistência Junto ao Leito , SARS-CoV-2/isolamento & purificação , Teste de Ácido Nucleico para COVID-19/instrumentação , Desenho de Equipamento , Genes Virais/genética , Humanos , Limite de Detecção , Técnicas de Diagnóstico Molecular , Técnicas de Amplificação de Ácido Nucleico , RNA Viral/genética , SARS-CoV-2/genética , Saliva/virologia , Sensibilidade e Especificidade
9.
Neuroimage Clin ; 30: 102603, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-33676164

RESUMO

OBJECTIVE: Structural reorganization following cerebellar infarcts is not yet known. This study aimed to demonstrate structural volumetric changes over time in the cortical vestibular and multisensory areas (i.e., brain plasticity) after acute cerebellar infarcts with vestibular and ocular motor symptoms. Additionally, we evaluated whether structural reorganization in the patients topographically correlates with cerebello-cortical connectivity that can be observed in healthy participants. METHODS: We obtained high-resolution structural imaging in seven patients with midline cerebellar infarcts at two time points. These data were compared to structural imaging of a group of healthy age-matched controls using voxel-based morphometry (2×2 ANOVA approach). The maximum overlap of the infarcts was used as a seed region for a separate resting-state functional connectivity analysis in healthy volunteers. RESULTS: Volumetric changes were detected in the multisensory cortical vestibular areas around the parieto-opercular and (retro-) insular cortex. Furthermore, structural reorganization was evident in parts of the frontal, temporal, parietal, limbic, and occipital lobes and reflected functional connections between the main infarct regions in the cerebellum and the cerebral cortex in healthy individuals. CONCLUSIONS: This study demonstrates structural reorganization in the parieto-opercular insular vestibular cortex after acute vestibulo-cerebellar infarcts. Additionally, the widely distributed structural reorganization after midline cerebellar infarcts provides additional in vivo evidence for the multifaceted contribution of cerebellar processing to cortical functions that extend beyond vestibular or ocular motor function.


Assuntos
Acidente Vascular Cerebral , Vestíbulo do Labirinto , Córtex Cerebral/diagnóstico por imagem , Humanos , Imageamento por Ressonância Magnética , Plasticidade Neuronal , Acidente Vascular Cerebral/diagnóstico por imagem
10.
Nat Commun ; 12(1): 606, 2021 01 27.
Artigo em Inglês | MEDLINE | ID: mdl-33504770

RESUMO

Genome editing critically relies on selective recognition of target sites. However, despite recent progress, the underlying search mechanism of genome-editing proteins is not fully understood in the context of cellular chromatin environments. Here, we use single-molecule imaging in live cells to directly study the behavior of CRISPR/Cas9 and TALEN. Our single-molecule imaging of genome-editing proteins reveals that Cas9 is less efficient in heterochromatin than TALEN because Cas9 becomes encumbered by local searches on non-specific sites in these regions. We find up to a fivefold increase in editing efficiency for TALEN compared to Cas9 in heterochromatin regions. Overall, our results show that Cas9 and TALEN use a combination of 3-D and local searches to identify target sites, and the nanoscopic granularity of local search determines the editing outcomes of the genome-editing proteins. Taken together, our results suggest that TALEN is a more efficient gene-editing tool than Cas9 for applications in heterochromatin.


Assuntos
Proteína 9 Associada à CRISPR/metabolismo , Edição de Genes , Heterocromatina/metabolismo , Nucleases dos Efetores Semelhantes a Ativadores de Transcrição/metabolismo , Proteínas de Ligação a DNA/metabolismo , Células HEK293 , Células HeLa , Humanos , Imagem Individual de Molécula
11.
Ann Clin Transl Neurol ; 7(10): 1788-1801, 2020 10.
Artigo em Inglês | MEDLINE | ID: mdl-32856758

RESUMO

OBJECTIVE: Patients with acute central vestibular syndrome suffer from vertigo, spontaneous nystagmus, postural instability with lateral falls, and tilts of visual vertical. Usually, these symptoms compensate within months. The mechanisms of compensation in vestibular infarcts are yet unclear. This study focused on structural changes in gray and white matter volume that accompany clinical compensation. METHODS: We studied patients with acute unilateral brain stem infarcts prospectively over 6 months. Structural changes were compared between the acute phase and follow-up with a group of healthy controls using voxel-based morphometry. RESULTS: Restitution of vestibular function following brain stem infarcts was accompanied by downstream structural changes in multisensory cortical areas. The changes depended on the location of the infarct along the vestibular pathways in patients with pathological tilts of the SVV and on the quality of the vestibular percept (rotatory vs graviceptive) in patients with pontomedullary infarcts. Patients with pontomedullary infarcts with vertigo or spontaneous nystagmus showed volumetric increases in vestibular parietal opercular multisensory and (retro-) insular areas with right-sided preference. Compensation of graviceptive deficits was accompanied by adaptive changes in multiple multisensory vestibular areas in both hemispheres in lower brain stem infarcts and by additional changes in the motor system in upper brain stem infarcts. INTERPRETATION: This study demonstrates multisensory neuroplasticity in both hemispheres along with the clinical compensation of vestibular deficits following unilateral brain stem infarcts. The data further solidify the concept of a right-hemispheric specialization for core vestibular processing. The identification of cortical structures involved in central compensation could serve as a platform to launch novel rehabilitative treatments such as transcranial stimulations.


Assuntos
Infartos do Tronco Encefálico/patologia , Tronco Encefálico/patologia , Encéfalo/patologia , Vestíbulo do Labirinto/patologia , Adulto , Encéfalo/fisiopatologia , Tronco Encefálico/fisiopatologia , Infartos do Tronco Encefálico/fisiopatologia , Feminino , Lateralidade Funcional/fisiologia , Humanos , Masculino , Pessoa de Meia-Idade , Plasticidade Neuronal/fisiologia , Vertigem/patologia , Vertigem/fisiopatologia
12.
PLoS One ; 15(5): e0233262, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32413079

RESUMO

Previous unimodal PET and fMRI studies in humans revealed a reproducible vestibular brain activation pattern, but with variations in its weighting and expansiveness. Hybrid studies minimizing methodological variations at baseline conditions are rare and still lacking for task-based designs. Thus, we applied for the first time hybrid 3T PET-MRI scanning (Siemens mMR) in healthy volunteers using galvanic vestibular stimulation (GVS) in healthy volunteers in order to directly compare H215O-PET and BOLD MRI responses. List mode PET acquisition started with the injection of 750 MBq H215O simultaneously to MRI EPI sequences. Group-level statistical parametric maps were generated for GVS vs. rest contrasts of PET, MR-onset (event-related), and MR-block. All contrasts showed a similar bilateral vestibular activation pattern with remarkable proximity of activation foci. Both BOLD contrasts gave more bilateral wide-spread activation clusters than PET; no area showed contradictory signal responses. PET still confirmed the right-hemispheric lateralization of the vestibular system, whereas BOLD-onset revealed only a tendency. The reciprocal inhibitory visual-vestibular interaction concept was confirmed by PET signal decreases in primary and secondary visual cortices, and BOLD-block decreases in secondary visual areas. In conclusion, MRI activation maps contained a mixture of CBF measured using H215O-PET and additional non-CBF effects, and the activation-deactivation pattern of the BOLD-block appears to be more similar to the H215O-PET than the BOLD-onset.


Assuntos
Encéfalo/diagnóstico por imagem , Encéfalo/fisiologia , Imageamento por Ressonância Magnética , Imagem Multimodal , Tomografia por Emissão de Pósitrons , Vestíbulo do Labirinto/fisiologia , Mapeamento Encefálico , Circulação Cerebrovascular , Estimulação Elétrica , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Oxigênio/sangue , Percepção/fisiologia
13.
Oral Maxillofac Surg ; 24(2): 151-156, 2020 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-32002693

RESUMO

PURPOSE: In cases of highly atrophic alveolar ridges, augmentation procedures became a frequent procedure to gain optimal conditions for dental implants. Especially in the maxilla sinus floor elevation procedures represent the gold standard pre-prosthetic and mainly successful procedure. The perforation of the Schneiderian is one of the most common complications. The aim of this study was to evaluate whether the intraoperative perforation of the Schneiderian membrane has an impact on long-term implant success. METHODS: Thirty-four patients from a former study collective of the years 2005 and 2006 with a total of 41 perforations were invited for a follow-up examination to determine the long-term success rates after sinus floor elevation and subsequent implantation. RESULTS: Twenty-one patients with 25 perforations were subsequently re-evaluated. One implant was lost due to a of periimplant infection after 232 days, resulting in an implant survival rate of 98% within a mean follow-up period of 8.9 years (± 1.5 years). CONCLUSION: Regarding the long-term success, there was no increased risk for implant failure or other persisting complications, e.g., sinusitis, after intraoperative perforation during sinus floor elevation in this study.


Assuntos
Implantes Dentários , Levantamento do Assoalho do Seio Maxilar , Implantação Dentária Endóssea , Falha de Restauração Dentária , Humanos , Maxila , Seio Maxilar , Mucosa Nasal , Fatores de Risco
14.
J Craniomaxillofac Surg ; 46(11): 1934-1938, 2018 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-30249486

RESUMO

Oftentimes the discussion of long-term success rates and treatment modalities becomes a central issue in consultations with patients. The aim of this study was to retrospectively evaluate survival rates of teeth after apicoectomy in an established private practice for Oral and Maxillofacial Surgery in Kiel, Germany. All teeth treated with apicoectomy between 2001 and 2006 were included. Treatment success was previously defined as preservation of the tooth. Putative influence factors on success as kind and quality of endodontic treatment, additional intraoperative endodontic filling, inflammatory status, tooth mobility, and pre- and postoperative X-rays were further evaluated. A total of 149 teeth could be included. The mean observation period was 6.3 (SD: 4.4) years. In all, 48.3% of these teeth could be retained after a 10-year period. Teeth that received an additional retrograde root canal filling during surgery resulted in a significantly higher success rate (p = 0.0237) compared to those with orthograde root canal fillings or without additional endodontic treatment. The quality of endodontic treatment had no impact (p = 0.125). Our results suggest that apical surgery is a reliable procedure to treat and ensure the survival of symptomatic teeth in the posterior region for several years. A significant improvement was further determined for a retrograde filling.


Assuntos
Apicectomia/efeitos adversos , Perda de Dente/etiologia , Feminino , Humanos , Masculino , Radiografia Dentária , Estudos Retrospectivos , Fatores de Tempo , Perda de Dente/diagnóstico por imagem
15.
Ann Clin Transl Neurol ; 5(6): 717-729, 2018 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-29928655

RESUMO

OBJECTIVE: Functional dizziness syndromes are among the most common diagnoses made in patients with chronic dizziness, but their underlying neural characteristics are largely unknown. The aim of this neuroimaging study was to analyze the disease-specific brain changes in patients with phobic postural vertigo (PPV). METHODS: We measured brain morphology, task response, and functional connectivity in 44 patients with PPV and 44 healthy controls. RESULTS: The analyses revealed a relative structural increase in regions of the prefrontal cortex and the associated thalamic projection zones as well as in the primary motor cortex. Morphological increases in the ventrolateral prefrontal cortex positively correlated with disease duration, whereas increases in dorsolateral, medial, and ventromedial prefrontal areas positively correlated with the Beck depression index. Visual motion stimulation caused an increased task-dependent activity in the subgenual anterior cingulum and a significantly longer duration of the motion aftereffect in the patients. Task-based functional connectivity analyses revealed aberrant involvement of interoceptive, fear generalization, and orbitofrontal networks. INTERPRETATION: Our findings agree with some of the typical characteristics of functional dizziness syndromes, for example, excessive self-awareness, anxious appraisal, and obsessive controlling of posture. This first evidence indicates that the disease-specific mechanisms underlying PPV are related to networks involved in mood regulation, fear generalization, interoception, and cognitive control. They do not seem to be the result of aberrant processing in cortical visual, visual motion, or vestibular regions.

16.
Proc Natl Acad Sci U S A ; 115(25): 6353-6356, 2018 06 19.
Artigo em Inglês | MEDLINE | ID: mdl-29866820

RESUMO

Understanding Hadean (>4 Ga) Earth requires knowledge of its crust. The composition of the crust and volatiles migrating through it directly influence the makeup of the atmosphere, the composition of seawater, and nutrient availability. Despite its importance, there is little known and less agreed upon regarding the nature of the Hadean crust. By analyzing the 87Sr/86Sr ratio of apatite inclusions in Archean zircons from Nuvvuagittuq, Canada, we show that its protolith had formed a high (>1) Rb/Sr ratio reservoir by at least 4.2 Ga. This result implies that the early crust had a broad range of igneous rocks, extending from mafic to highly silicic compositions.

17.
Neuroimage ; 176: 354-363, 2018 08 01.
Artigo em Inglês | MEDLINE | ID: mdl-29702184

RESUMO

Multisensory convergence and sensorimotor integration are important aspects for the mediation of higher vestibular cognitive functions at the cortical level. In contrast to the integration of vestibulo-visual or vestibulo-tactile perception, much less is known about the neural mechanism that mediates the integration of vestibular-otolith (linear acceleration/translation/gravity detection) and auditory processing. Vestibular-otolith and auditory afferents can be simultaneously activated using loud sound pressure stimulation, which is routinely used for testing cervical and ocular vestibular evoked myogenic potentials (VEMPs) in clinical neurotological testing. Due to the simultaneous activation of afferents there is always an auditory confound problem in fMRI studies of the neural topology of these systems. Here, we demonstrate that the auditory confounding problem can be overcome in a novel way that does not require the assumption of simple subtraction and additionally allows detection of non-linear changes in the response due to vestibular-otolith interference. We used a parametric sound pressure stimulation design that took each subject's vestibular stimulation threshold into account and analyzed for changes in BOLD-response below and above vestibular-otolith threshold. This approach helped to investigate the functional neuroanatomy of sound-induced auditory and vestibular integration using functional magnetic resonance imaging (fMRI). Results revealed that auditory and vestibular convergence are contained in overlapping regions of the caudal part of the superior temporal gyrus (STG) and the posterior insula. In addition, there are regions that were responsive only to suprathreshold stimulations, suggesting vestibular (otolith) signal processing in these areas. Based on these parametric analyses, we suggest that the caudal part of the STG and posterior insula could contain areas of vestibular contribution to auditory processing, i.e., higher vestibular cortices that provide multisensory integration that is important for tasks such as spatial localization of sound.


Assuntos
Percepção Auditiva/fisiologia , Mapeamento Encefálico/métodos , Córtex Cerebral/fisiologia , Propriocepção/fisiologia , Limiar Sensorial/fisiologia , Potenciais Evocados Miogênicos Vestibulares/fisiologia , Vestíbulo do Labirinto/fisiologia , Estimulação Acústica , Adulto , Feminino , Humanos , Imageamento por Ressonância Magnética , Masculino , Membrana dos Otólitos/fisiologia , Lobo Temporal/fisiologia
18.
J Biotechnol ; 275: 53-59, 2018 Jun 10.
Artigo em Inglês | MEDLINE | ID: mdl-29660472

RESUMO

To efficiently ferment intermediate cellodextrins released during cellulose hydrolysis, Saccharomyces cerevisiae has been engineered by introduction of a heterologous cellodextrin utilizing pathway consisting of a cellodextrin transporter and either an intracellular ß-glucosidase or a cellobiose phosphorylase. Among two types of cellodextrin transporters, the passive facilitator CDT-2 has not enabled better cellobiose fermentation than the active transporter CDT-1, which suggests that the CDT-2 might be engineered to provide energetic benefits over the active transporter in cellobiose fermentation. We attempted to improve cellobiose transporting activity of CDT-2 through laboratory evolution. Nine rounds of a serial subculture of S. cerevisiae expressing CDT-2 and cellobiose phosphorylase on cellobiose led to the isolation of an evolved strain capable of fermenting cellobiose to ethanol 10-fold faster than the original strain. After sequence analysis of the isolated CDT-2, a single point mutation on CDT-2 (N306I) was revealed to be responsible for enhanced cellobiose fermentation. Also, the engineered strain expressing the mutant CDT-2 with cellobiose phosphorylase showed a higher ethanol yield than the engineered strain expressing CDT-1 and intracellular ß-glucosidase under anaerobic conditions, suggesting that CDT-2 coupled with cellobiose phosphorylase may be better choices for efficient production of cellulosic ethanol with the engineered yeast.


Assuntos
Celobiose/química , Glucosiltransferases/genética , Proteínas de Membrana Transportadoras/genética , Saccharomyces cerevisiae/crescimento & desenvolvimento , Celulose/análogos & derivados , Celulose/metabolismo , Dextrinas/metabolismo , Fermentação , Glucosiltransferases/metabolismo , Proteínas de Membrana Transportadoras/metabolismo , Engenharia Metabólica , Proteínas Recombinantes , Saccharomyces cerevisiae/genética , Saccharomyces cerevisiae/metabolismo
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