Your browser doesn't support javascript.
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 16.674
Filtrar
1.
Chem Biol Interact ; 324: 109092, 2020 Jun 01.
Artigo em Inglês | MEDLINE | ID: mdl-32278739

RESUMO

Human butyrylcholinesterase (HuBChE) is a stoichiometric bioscavenger that protects from the toxicity of nerve agents. Non-human primates are suitable models for toxicity studies that cannot be performed in humans. We evaluated the biochemical properties of native macaque (MaBChE) tetramers, compared to recombinant MaBChE monomers, PEGylated recombinant MaBChE tetramers and monomers, and native HuBChE tetramers. Km and kcat values for butyrylthiocholine were independent of subunit assembly status. The Km for all forms of MaBChE was about 70 µM, compared to 13 µM for HuBChE. The kcat was about 100,000 min-1 for MaBChE and 30,000 min-1 for HuBChE. The reversible inhibitor ethopropazine had similar Ki values of 0.05 µM for all MaBChE forms and HuBChE. The bimolecular rate constant, ki, for inhibition by diisopropylfluorophosphate (DFP), an analog of sarin, was 2.2 to 2.5 × 107 M-1 min-1 for all MaBChE forms and for HuBChE. A major difference between MaBChE and HuBChE was the rate of reactivation by 2-PAM. The second order rate constant for reactivation of DFP-inhibited MaBChE by 2-PAM was 1.4 M-1 min-1, but was 380 fold faster for DFP-inhibited HuBChE (kr 531 M-1 min-1). The acyl pocket of MaBChE has Leu285 in place of Pro285 in HuBChE. The reactivation rate of DFP-inhibited HuBChE mutant P285L by 2-PAM was reduced 5.8-fold (kr 92 M-1 min-1) indicating that P285 determines whether 2-PAM binds in an orientation that favors release of diisopropylphosphate. DFP-inhibited MaBChE treated with 0.2 M 2-PAM recovered 10% of its original activity, whereas DFP-inhibited HuBChE recovered 80% activity. It was concluded that the biochemical properties of MaBChE are similar to those of HuBChE except for the reactivation of DFP-inhibited BChE.


Assuntos
Butirilcolinesterase/química , Reativadores da Colinesterase/química , Compostos de Pralidoxima/química , Prolina/química , Sequência de Aminoácidos , Animais , Inibidores da Colinesterase/farmacologia , Humanos , Cinética , Macaca , Macaca mulatta , Fenotiazinas/farmacologia , Alinhamento de Sequência
3.
Nat Commun ; 11(1): 697, 2020 02 04.
Artigo em Inglês | MEDLINE | ID: mdl-32019929

RESUMO

The integration of synaptic inputs onto dendrites provides the basis for neuronal computation. Whereas recent studies have begun to outline the spatial organization of synaptic inputs on individual neurons, the underlying principles related to the specific neural functions are not well understood. Here we perform two-photon dendritic imaging with a genetically-encoded glutamate sensor in awake monkeys, and map the excitatory synaptic inputs on dendrites of individual V1 superficial layer neurons with high spatial and temporal resolution. We find a functional integration and trade-off between orientation-selective and color-selective inputs in basal dendrites of individual V1 neurons. Synaptic inputs on dendrites are spatially clustered by stimulus feature, but functionally scattered in multidimensional feature space, providing a potential substrate of local feature integration on dendritic branches. Furthermore, apical dendrite inputs have larger receptive fields and longer response latencies than basal dendrite inputs, suggesting a dominant role for apical dendrites in integrating feedback in visual information processing.


Assuntos
Neurônios/fisiologia , Navegação Espacial , Animais , Dendritos/fisiologia , Potenciais Pós-Sinápticos Excitadores , Macaca , Modelos Neurológicos , Sinapses/fisiologia
4.
PLoS One ; 15(2): e0228334, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32074115

RESUMO

The brain works as a large-scale complex network, known as the connectome. The strength of the connections between two brain regions in the connectome is commonly estimated by calculating the correlations between their patterns of activation. This approach relies on the assumption that the activation of connected regions occurs together and at the same time. However, there are delays between the activation of connected regions due to excitatory and inhibitory connections. Here, we propose a method to harvest this additional information and reconstruct the structural brain connectome using delayed correlations. This delayed-correlation method correctly identifies 70% to 80% of connections of simulated brain networks, compared to only 5% to 25% of connections detected by the standard methods; this result is robust against changes in the network parameters (small-worldness, excitatory vs. inhibitory connection ratio, weight distribution) and network activation dynamics. The delayed-correlation method predicts more accurately both the global network properties (characteristic path length, global efficiency, clustering coefficient, transitivity) and the nodal network properties (nodal degree, nodal clustering, nodal global efficiency), particularly at lower network densities. We obtain similar results in networks derived from animal and human data. These results suggest that the use of delayed correlations improves the reconstruction of the structural brain connectome and open new possibilities for the analysis of the brain connectome, as well as for other types of networks.


Assuntos
Encéfalo/fisiologia , Conectoma/métodos , Animais , Gatos , Humanos , Macaca , Camundongos , Modelos Biológicos
5.
Nat Commun ; 11(1): 70, 2020 01 07.
Artigo em Inglês | MEDLINE | ID: mdl-31911610

RESUMO

Vertical transmission accounts for most human immunodeficiency virus (HIV) infection in children, and treatments for newborns are needed to abrogate infection or limit disease progression. We showed previously that short-term broadly neutralizing antibody (bNAb) therapy given 24 h after oral exposure cleared simian-human immunodeficiency virus (SHIV) in a macaque model of perinatal infection. Here, we report that all infants given either a single dose of bNAbs at 30 h, or a 21-day triple-drug ART regimen at 48 h, are aviremic with almost no virus in tissues. In contrast, bNAb treatment beginning at 48 h leads to tight control without adaptive immune responses in half of animals. We conclude that both bNAbs and ART mediate effective post-exposure prophylaxis in infant macaques within 30-48 h of oral SHIV exposure. Our findings suggest that optimizing the treatment regimen may extend the window of opportunity for preventing perinatal HIV infection when treatment is delayed.


Assuntos
Fármacos Anti-HIV/administração & dosagem , Anticorpos Neutralizantes/administração & dosagem , Anticorpos Anti-HIV/administração & dosagem , Transmissão Vertical de Doença Infecciosa/prevenção & controle , Síndrome de Imunodeficiência Adquirida dos Símios/prevenção & controle , Imunidade Adaptativa , Animais , Modelos Animais de Doenças , Feminino , Infecções por HIV/imunologia , Infecções por HIV/prevenção & controle , Infecções por HIV/transmissão , HIV-1/imunologia , HIV-1/fisiologia , Humanos , Macaca , Macaca mulatta , Masculino , Profilaxia Pós-Exposição , Síndrome de Imunodeficiência Adquirida dos Símios/imunologia , Síndrome de Imunodeficiência Adquirida dos Símios/transmissão , Vírus da Imunodeficiência Símia/imunologia , Vírus da Imunodeficiência Símia/fisiologia
6.
7.
Parasitol Res ; 119(2): 741-748, 2020 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-31897788

RESUMO

Blastocystis is an enteral eukaryote with an omnipresent existence in animals and humans globally. Animals have been proposed to be a major reservoir for the transmission of Blastocystis to individuals due to their high prevalence and large amount of zoonotic subtypes. However, limited data on Blastocystis infection in experimental macaques in China exists. The objective of the current study was to investigate the frequency and subtypes of Blastocystis infection in macaques in southwestern China. A total of 505 fecal samples were collected from experimental macaques in Yunnan province and were analyzed by nested PCR and phylogenetic analyses on the basis of small subunit rRNA (SSU rRNA) gene fragments. A total of 235 specimens were positive for Blastocystis sp., and the prevalence of Blastocystis sp. was 46.5% (235/505). Significant differences in prevalence were also observed among the various species of macaques (P < 0.0133, df = 2, χ2 = 8.64) and the different feed types (P < 0.0093, df = 1, χ2 = 6.77). Moreover, three zoonotic subtypes, ST1, ST3, and ST5, were identified by DNA sequence analysis. There were mainly single subtype infections with some mixed subtype infections, and the predominant subtype was ST3. The results suggested a high prevalence and diversified subtypes in macaques in Yunnan province, southwestern China. Macaques are likely to be potential reservoirs capable of zoonotic transmission of Blastocystis sp. to humans. To our knowledge, this study is the first large-scale systematic analysis of Blastocystis sp. colonization in Yunnan province in the subtropics of China; these results contribute to the in-depth study of genetic characteristics and the prevention, control, and treatment of Blastocystis sp. in macaques in Yunnan province and other regions.


Assuntos
Infecções por Blastocystis/epidemiologia , Infecções por Blastocystis/veterinária , Blastocystis/classificação , Blastocystis/genética , Animais , Blastocystis/isolamento & purificação , Infecções por Blastocystis/parasitologia , China/epidemiologia , Fezes/parasitologia , Variação Genética/genética , Humanos , Macaca , Filogenia , Reação em Cadeia da Polimerase , Prevalência , Zoonoses/parasitologia
9.
Proc Natl Acad Sci U S A ; 117(6): 3232-3238, 2020 02 11.
Artigo em Inglês | MEDLINE | ID: mdl-31988119

RESUMO

Theories of cerebellar functions posit that the cerebellum implements internal models for online correction of motor actions and sensory estimation. As an example of such computations, an internal model resolves a sensory ambiguity where the peripheral otolith organs in the inner ear sense both head tilts and translations. Here we exploit the response dynamics of two functionally coupled Purkinje cell types in the vestibular part of the caudal vermis (lobules IX and X) to understand their role in this computation. We find that one population encodes tilt velocity, whereas the other, translation-selective, population encodes linear acceleration. We predict that an intermediate neuronal type should temporally integrate the output of tilt-selective cells into a tilt position signal.


Assuntos
Potenciais de Ação/fisiologia , Vermis Cerebelar , Movimento/fisiologia , Células de Purkinje/fisiologia , Animais , Vermis Cerebelar/citologia , Vermis Cerebelar/fisiologia , Macaca , Masculino , Postura/fisiologia , Rotação , Vestíbulo do Labirinto/fisiologia
10.
Am J Respir Crit Care Med ; 201(4): 469-477, 2020 02 15.
Artigo em Inglês | MEDLINE | ID: mdl-31647877

RESUMO

Rationale: Direct evidence for persistence of Mycobacterium tuberculosis (Mtb) during asymptomatic latent tuberculosis infection (LTBI) in humans is currently lacking. Moreover, although a 12-week regimen of once-weekly isoniazid and rifapentine (3HP) is currently recommended by the CDC as treatment for LTBI, experimental evidence for 3HP-mediated clearance of persistent Mtb infection in human lungs has not been established.Objectives: Using a nonhuman primate (NHP) model of TB, we sought to assess 3HP treatment-mediated clearance of Mtb infection in latently infected macaques.Methods: Sixteen NHPs were infected via inhalation with ∼10 cfu of Mtb CDC1551, after which asymptomatic animals were either treated with 3HP or left untreated. Pharmacokinetics of the 3HP regimen were measured. Following treatment, animals were coinfected with simian immunodeficiency virus to assess reactivation of LTBI and development of active TB disease.Measurements and Main Results: Fourteen NHPs remained free of clinical signs or microbiological evidence of active TB following infection with Mtb and were subsequently either treated with 3HP (n = 7) or left untreated (n = 7). Untreated NHPs were asymptomatic for 7 months but harbored persistent Mtb infection, as shown by reactivation of latent infection following simian immunodeficiency virus coinfection. However, none of the treated animals developed TB reactivation disease, and they remained without clinical or microbiological evidence of persistent bacilli, suggesting treatment-mediated clearance of bacteria.Conclusions: Mtb can persist in asymptomatic macaques for at least 7 months. Furthermore, 3HP treatment effectively cleared bacteria and prevented reactivation of TB in latently infected macaques.


Assuntos
Antibióticos Antituberculose/uso terapêutico , Antituberculosos/uso terapêutico , Isoniazida/uso terapêutico , Tuberculose Latente/tratamento farmacológico , Mycobacterium tuberculosis/efeitos dos fármacos , Rifampina/análogos & derivados , Tuberculose/tratamento farmacológico , Animais , Quimioterapia Combinada , Macaca , Modelos Animais , Rifampina/uso terapêutico , Resultado do Tratamento
12.
Int J Syst Evol Microbiol ; 70(2): 751-758, 2020 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-31674895

RESUMO

Huge numbers of bacteria reside in the digestive tract of most animals. During an investigation into the bacterial diversity of primates, strain YIM 102668T was isolated. When neighbour-joining phylogenetic analysis based on 16S rRNA gene sequences was conducted, strain YIM 102668T formed a cluster within the family Flavobacteriaceae and in a lineage not associated with any known group of previously proposed genera. Closely related genera were Algoriella (94.8 %), Chishuiella (94.8 %), Empedobacter (highest 94.6 %), Moheibacter (90.9 %) and Weeksella (90.6 %). In addition, strain YIM 102668T contained MK-6 as the predominant respiratory quinone and iso-C15 : 0 as the major fatty acid. The major polar lipid was phosphatidylethanolamine and the genomic DNA G+C content was 30.6 mol%. These chemotaxonomic characterizations confirmed that strain YIM 102668T belonged to the family Flavobacteriaceae. Supported by the results of phylogenetic, phenotypic and chemotaxonomic analyses, we propose that strain YIM 102668T represents a novel genus, for which the name Faecalibacter macacae gen. nov., sp. nov. is proposed. The type strain is YIM 102668T (=KCTC 52109T=CCTCC AB 2016016T).


Assuntos
Flavobacteriaceae/classificação , Macaca/microbiologia , Filogenia , Animais , Técnicas de Tipagem Bacteriana , Composição de Bases , China , DNA Bacteriano/genética , Ácidos Graxos/química , Fezes/microbiologia , Flavobacteriaceae/isolamento & purificação , Fosfatidiletanolaminas/química , RNA Ribossômico 16S/genética , Análise de Sequência de DNA , Vitamina K 2/análogos & derivados , Vitamina K 2/química
13.
Neuron ; 105(2): 370-384.e8, 2020 01 22.
Artigo em Inglês | MEDLINE | ID: mdl-31813653

RESUMO

The medial frontal cortex has been linked to voluntary action, but an explanation of why decisions to act emerge at particular points in time has been lacking. We show that, in macaques, decisions about whether and when to act are predicted by a set of features defining the animal's current and past context; for example, respectively, cues indicating the current average rate of reward and recent previous voluntary action decisions. We show that activity in two brain areas-the anterior cingulate cortex and basal forebrain-tracks these contextual factors and mediates their effects on behavior in distinct ways. We use focused transcranial ultrasound to selectively and effectively stimulate deep in the brain, even as deep as the basal forebrain, and demonstrate that alteration of activity in the two areas changes decisions about when to act.


Assuntos
Prosencéfalo Basal/fisiologia , Tomada de Decisões/fisiologia , Giro do Cíngulo/fisiologia , Estimulação Acústica , Animais , Sinais (Psicologia) , Estimulação Encefálica Profunda/métodos , Neuroimagem Funcional , Macaca , Imagem por Ressonância Magnética , Masculino , Vias Neurais/fisiologia , Fatores de Tempo , Ondas Ultrassônicas
16.
17.
Invest Ophthalmol Vis Sci ; 60(15): 4972-4984, 2019 12 02.
Artigo em Inglês | MEDLINE | ID: mdl-31790560

RESUMO

Purpose: The subbasal nerve plexus (SNP) is the densest and most recognizable component of the mammalian corneal innervation; however, the anatomical configuration of the SNP in most animal models remains incompletely described. The purpose of the current study is to describe in detail the SNP architecture in eight different mammals, including several popular animal models used in cornea research. Methods: Corneal nerves in mouse, rat, guinea pig, rabbit, dog, macaque, domestic pig, and cow eyes were stained immunohistochemically with antiserum directed against neurotubulin. SNP architecture was documented by digital photomicrography and large-scale reconstructions, that is, corneal nerve maps, using a drawing tube attached to a light microscope. Results: Subbasal nerve fibers (SNFs) in mice, rats, guinea pigs, dogs, and macaques radiated centrally from the corneoscleral limbus toward the corneal apex in a whorl-like or spiraling pattern. SNFs in rabbit and bovine corneas swept horizontally across the ocular surface in a temporal-to-nasal direction and converged on the inferonasal limbus without forming a spiral. SNFs in the pig cornea radiated centrifugally in all directions, like a starburst, from a focal point located equidistant between the corneal apex and the superior pole. Conclusions: The results of the present study have demonstrated for the first time substantial interspecies differences in the architectural organization of the mammalian SNP. The physiological significance of these different patterns and the mechanisms that regulate SNP pattern formation in the mammalian cornea remain incompletely understood and warrant additional investigation.


Assuntos
Anatomia Comparada , Córnea/inervação , Nervo Oftálmico/anatomia & histologia , Animais , Bovinos , Cães , Cobaias , Macaca , Camundongos , Microscopia Confocal , Modelos Animais , Fibras Nervosas , Coelhos , Ratos , Suínos , Gânglio Trigeminal/anatomia & histologia
18.
J Neuroinflammation ; 16(1): 244, 2019 Nov 30.
Artigo em Inglês | MEDLINE | ID: mdl-31785610

RESUMO

BACKGROUND: Autoantibodies against myelin oligodendrocyte glycoprotein (anti-MOG-Abs) occur in a majority of children with acquired demyelinating syndromes (ADS) and physiopathology is still under investigation. As cynomolgus macaques immunized with rhMOG, all develop an experimental autoimmune encephalomyelitis (EAE), we assessed relatedness between anti-MOG-Abs associated diseases in both species. METHODS: The study includes 27 children followed for ADS and nine macaques with rhMOG-induced EAE. MRI lesions, cytokines in blood, and CSF at onset of ADS or EAE, as well as histopathological features of brain lesions were compared. RESULTS: Twelve children with anti-MOG-Abs ADS (ADS MOG+) and nine macaques with EAE, presented increased IL-6 and G-CSF in the CSF, whereas no such signature was found in 15 ADS MOG-. Furthermore, IgG and C1q were associated to myelin and phagocytic cells in brains with EAE (n = 8) and in biopsies of ADS MOG+ (n = 2) but not ADS MOG- children (n = 1). Macaque brains also revealed prephagocytic lesions with IgG and C1q depositions but no leukocyte infiltration. CONCLUSIONS: Children with ADS MOG+ and macaques with EAE induced with rhMOG, present a similar cytokine signature in the CSF and a comparable aspect of brain lesions indicating analogous pathophysiological processes. In EAE, prephagocytic lesions points at IgG as an initial effector of myelin attack. These results support the pertinence of modeling ADS MOG+ in non-human primates to apprehend the natural development of anti-MOG-associated disease, find markers of evolution, and above all explore the efficacy of targeted therapies to test primate-restricted molecules.


Assuntos
Autoanticorpos/sangue , Doenças Desmielinizantes/sangue , Doenças Desmielinizantes/diagnóstico por imagem , Encefalomielite Autoimune Experimental/sangue , Encefalomielite Autoimune Experimental/diagnóstico por imagem , Glicoproteína Mielina-Oligodendrócito/sangue , Adolescente , Animais , Autoanticorpos/líquido cefalorraquidiano , Criança , Pré-Escolar , Doenças Desmielinizantes/líquido cefalorraquidiano , Encefalomielite Autoimune Experimental/líquido cefalorraquidiano , Feminino , Humanos , Macaca , Masculino , Glicoproteína Mielina-Oligodendrócito/líquido cefalorraquidiano
19.
PLoS One ; 14(12): e0225904, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31830760

RESUMO

Detection of misfolded prion protein, PrPTSE, in biological samples is important to develop antemortem tests for transmissible spongiform encephalopathies (TSEs). The real-time quaking-induced conversion (RT-QuIC) assay detects PrPTSE but requires dedicated equipment and relatively long incubation times when applied to samples containing extremely low levels of PrPTSE. It was shown that a microplate shaker with heated top (Thermomixer-C) accelerated amplification of PrPTSE in brain suspensions of 263K scrapie and sporadic Creutzfeldt-Jakob disease (sCJD). We expanded the investigation to include TSE agents previously untested, including chronic wasting disease (CWD), macaque-adapted variant CJD (vCJD) and human vCJD, and we further characterized the assays conducted at 42°C and 55°C. PrPTSE from all brains containing the TSE agents were successfully amplified using a truncated hamster recombinant protein except for human vCJD which required truncated bank vole recombinant protein. We compared assays conducted at 42°C on Thermomixer-C, Thermomixer-R (without heated top) and on a fluorimeter used for RT-QuIC. QuIC on Thermomixer-R achieved in only 18 hours assay sensitivity similar to that of RT-QuIC read at 60 hours (or 48 hours with sCJD). QuIC on Thermomixer-C required 24 hours to complete and the endpoint titers of some TSEs were 10-fold lower than those obtained with RT-QuIC and Thermomixer-R. Conversely, at 55°C, the reactions with sCJD and CWD on Thermomixer-C achieved the same sensitivity as with RT-QuIC but in shorter times. Human vCJD samples tested at higher temperatures gave rise to high reactivity in wells containing normal control samples. Similarly, reactions on Thermomixer-R were unsuitable at 55°C. The main disadvantage of Thermomixers is that they cannot track formation of PrP fibrils in real time, a feature useful in some applications. The main advantages of Thermomixers are that they need shorter reaction times to detect PrPTSE, are easier to use, involve more robust equipment, and are relatively affordable. Improvements to QuIC using thermal mixers may help develop accessible antemortem TSE tests.


Assuntos
Encéfalo/metabolismo , Doenças Priônicas/etiologia , Doenças Priônicas/metabolismo , Proteínas Priônicas/química , Proteínas Priônicas/metabolismo , Animais , Encéfalo/patologia , Síndrome de Creutzfeldt-Jakob , Cricetinae , Modelos Animais de Doenças , Humanos , Macaca , Doenças Priônicas/patologia , Deficiências na Proteostase , Proteínas Recombinantes , Temperatura , Doença de Emaciação Crônica
20.
Nat Commun ; 10(1): 5674, 2019 12 12.
Artigo em Inglês | MEDLINE | ID: mdl-31831741

RESUMO

Imprinted genes are expressed from a single parental allele, with the other allele often silenced by DNA methylation (DNAme) established in the germline. While species-specific imprinted orthologues have been documented, the molecular mechanisms underlying the evolutionary switch from biallelic to imprinted expression are unknown. During mouse oogenesis, gametic differentially methylated regions (gDMRs) acquire DNAme in a transcription-guided manner. Here we show that oocyte transcription initiating in lineage-specific endogenous retroviruses (ERVs) is likely responsible for DNAme establishment at 4/6 mouse-specific and 17/110 human-specific imprinted gDMRs. The latter are divided into Catarrhini- or Hominoidea-specific gDMRs embedded within transcripts initiating in ERVs specific to these primate lineages. Strikingly, imprinting of the maternally methylated genes Impact and Slc38a4 was lost in the offspring of female mice harboring deletions of the relevant murine-specific ERVs upstream of these genes. Our work reveals an evolutionary mechanism whereby maternally silenced genes arise from biallelically expressed progenitors.


Assuntos
Metilação de DNA , Evolução Molecular , Impressão Genômica , Regiões Promotoras Genéticas/genética , Retroviridae/genética , Animais , Epigenômica , Feminino , Células Germinativas , Haplorrinos , Humanos , Macaca , Masculino , Camundongos , Oócitos/metabolismo , Pan troglodytes , Primatas , Especificidade da Espécie , Sequências Repetidas Terminais
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA