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2.
Nature ; 592(7854): 409-413, 2021 04.
Artigo em Inglês | MEDLINE | ID: mdl-33692544

RESUMO

The output of the retina is organized into many detector grids, called 'mosaics', that signal different features of visual scenes to the brain1-4. Each mosaic comprises a single type of retinal ganglion cell (RGC), whose receptive fields tile visual space. Many mosaics arise as pairs, signalling increments (ON) and decrements (OFF), respectively, of a particular visual feature5. Here we use a model of efficient coding6 to determine how such mosaic pairs should be arranged to optimize the encoding of natural scenes. We find that information is maximized when these mosaic pairs are anti-aligned, meaning that the distances between the receptive field centres across mosaics are greater than expected by chance. We tested this prediction across multiple receptive field mosaics acquired using large-scale measurements of the light responses of rat and primate RGCs. ON and OFF RGC pairs with similar feature selectivity had anti-aligned receptive field mosaics, consistent with this prediction. ON and OFF RGC types that encode distinct features have independent mosaics. These results extend efficient coding theory beyond individual cells to predict how populations of diverse types of RGC are spatially arranged.


Assuntos
Retina/citologia , Retina/fisiologia , Campos Visuais/fisiologia , Animais , Feminino , Macaca , Masculino , Modelos Neurológicos , Ratos , Ratos Long-Evans , Células Ganglionares da Retina/fisiologia
3.
Gut Microbes ; 13(1): 1-19, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-33685349

RESUMO

The current pandemic of coronavirus disease (COVID) 2019 constitutes a global public health issue. Regarding the emerging importance of the gut-lung axis in viral respiratory infections, analysis of the gut microbiota's composition and functional activity during a severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection might be instrumental in understanding and controling COVID 19. We used a nonhuman primate model (the macaque), that recapitulates mild COVID-19 symptoms, to analyze the effects of a SARS-CoV-2 infection on dynamic changes of the gut microbiota. 16S rRNA gene profiling and analysis of ß diversity indicated significant changes in the composition of the gut microbiota with a peak at 10-13 days post-infection (dpi). Analysis of bacterial abundance correlation networks confirmed disruption of the bacterial community at 10-13 dpi. Some alterations in microbiota persisted after the resolution of the infection until day 26. Some changes in the relative bacterial taxon abundance associated with infectious parameters. Interestingly, the relative abundance of Acinetobacter (Proteobacteria) and some genera of the Ruminococcaceae family (Firmicutes) was positively correlated with the presence of SARS-CoV-2 in the upper respiratory tract. Targeted quantitative metabolomics indicated a drop in short-chain fatty acids (SCFAs) and changes in several bile acids and tryptophan metabolites in infected animals. The relative abundance of several taxa known to be SCFA producers (mostly from the Ruminococcaceae family) was negatively correlated with systemic inflammatory markers while the opposite correlation was seen with several members of the genus Streptococcus. Collectively, SARS-CoV-2 infection in a nonhuman primate is associated with changes in the gut microbiota's composition and functional activity.


Assuntos
/microbiologia , Microbioma Gastrointestinal , Macaca/microbiologia , Macaca/virologia , Animais , Bactérias/classificação , Modelos Animais de Doenças , Fezes , Feminino , Metaboloma , RNA Ribossômico 16S/genética
5.
J Affect Disord ; 286: 204-212, 2021 05 01.
Artigo em Inglês | MEDLINE | ID: mdl-33740637

RESUMO

INTRODUCTION: Attenuated adult hippocampal neurogenesis may manifest in affective symptomatology and/or resistance to antidepressant treatment. While early-life adversity and the short variant ('s') of the serotonin transporter gene's long polymorphic region (5-HTTLPR) are suggested as interacting risk factors for affective disorders, no studies have examined whether their superposed risk effectuates neurogenic changes into adulthood. Similarly, it is not established whether reduced hippocampal volume in adolescence, variously identified as a marker and antecedent of affective disorders, anticipates diminished adult neurogenesis. We investigate these potential developmental precursors of neurogenic alterations using a bonnet macaque model. METHODS: Twenty-five male infant bonnet macaques were randomized to stressed [variable foraging demand (VFD)] or normative [low foraging demand (LFD)] rearing protocols and genotyped for 5-HTTLPR polymorphisms. Adolescent MRI brain scans (mean age 4.2y) were available for 14 subjects. Adult-born neurons were detected post-mortem (mean age 8.6y) via immunohistochemistry targeting the microtubule protein doublecortin (DCX). Models were adjusted for age and weight. RESULTS: A putative vulnerability group (VG) of VFD-reared 's'-carriers (all 's/l') exhibited reduced neurogenesis compared to non-VG subjects. Neurogenesis levels were positively predicted by ipsilateral hippocampal volume normalized for total brain volume, but not by contralateral or raw hippocampal volume. LIMITATIONS: No 's'-carriers were identified in LFD-reared subjects, precluding a 2×2 factorial analysis. CONCLUSION: The 's' allele (with adverse rearing) and low adolescent hippocampal volume portend a neurogenic deficit in adult macaques, suggesting persistent alterations in hippocampal plasticity may contribute to these developmental factors' affective risk in humans.


Assuntos
Experiências Adversas da Infância , Proteínas da Membrana Plasmática de Transporte de Serotonina , Adolescente , Adulto , Animais , Criança , Pré-Escolar , Hipocampo/diagnóstico por imagem , Hipocampo/metabolismo , Humanos , Macaca/metabolismo , Masculino , Neurogênese/genética , Proteínas da Membrana Plasmática de Transporte de Serotonina/genética , Proteínas da Membrana Plasmática de Transporte de Serotonina/metabolismo , Estresse Psicológico/genética
6.
Molecules ; 26(5)2021 Feb 26.
Artigo em Inglês | MEDLINE | ID: mdl-33652764

RESUMO

Infection of hosts by morbilliviruses is facilitated by the interaction between viral hemagglutinin (H-protein) and the signaling lymphocytic activation molecule (SLAM). Recently, the functional importance of the n-terminal region of human SLAM as a measles virus receptor was demonstrated. However, the functional roles of this region in the infection process by other morbilliviruses and host range determination remain unknown, partly because this region is highly flexible, which has hampered accurate structure determination of this region by X-ray crystallography. In this study, we analyzed the interaction between the H-protein from canine distemper virus (CDV-H) and SLAMs by a computational chemistry approach. Molecular dynamics simulations and fragment molecular orbital analysis demonstrated that the unique His28 in the N-terminal region of SLAM from Macaca is a key determinant that enables the formation of a stable interaction with CDV-H, providing a basis for CDV infection in Macaca. The computational chemistry approach presented should enable the determination of molecular interactions involving regions of proteins that are difficult to predict from crystal structures because of their high flexibility.


Assuntos
Vírus da Cinomose Canina/genética , Cinomose/genética , Doenças do Cão/genética , Família de Moléculas de Sinalização da Ativação Linfocitária/genética , Animais , Química Computacional , Cinomose/virologia , Vírus da Cinomose Canina/patogenicidade , Doenças do Cão/virologia , Cães , Humanos , Macaca/virologia , Mutação Puntual/genética , Ligação Proteica/genética , Receptores Virais/genética , Família de Moléculas de Sinalização da Ativação Linfocitária/química , Família de Moléculas de Sinalização da Ativação Linfocitária/ultraestrutura , Especificidade da Espécie , Linfócitos T/virologia
7.
Nat Commun ; 12(1): 1403, 2021 03 03.
Artigo em Inglês | MEDLINE | ID: mdl-33658497

RESUMO

SARS-CoV-2 vaccines are advancing into human clinical trials, with emphasis on eliciting high titres of neutralising antibodies against the viral spike (S). However, the merits of broadly targeting S versus focusing antibody onto the smaller receptor binding domain (RBD) are unclear. Here we assess prototypic S and RBD subunit vaccines in homologous or heterologous prime-boost regimens in mice and non-human primates. We find S is highly immunogenic in mice, while the comparatively poor immunogenicity of RBD is associated with limiting germinal centre and T follicular helper cell activity. Boosting S-primed mice with either S or RBD significantly augments neutralising titres, with RBD-focussing driving moderate improvement in serum neutralisation. In contrast, both S and RBD vaccines are comparably immunogenic in macaques, eliciting serological neutralising activity that generally exceed levels in convalescent humans. These studies confirm recombinant S proteins as promising vaccine candidates and highlight multiple pathways to achieving potent serological neutralisation.


Assuntos
/uso terapêutico , /patogenicidade , Animais , Anticorpos Neutralizantes/imunologia , Formação de Anticorpos/fisiologia , Ensaio de Imunoadsorção Enzimática , Citometria de Fluxo , Humanos , Macaca , Masculino , Camundongos , Camundongos Endogâmicos BALB C , Camundongos Endogâmicos C57BL , Linfócitos T Auxiliares-Indutores/imunologia , Linfócitos T Auxiliares-Indutores/metabolismo , Vacinas Virais/uso terapêutico
8.
Neuron ; 109(8): 1381-1395.e7, 2021 04 21.
Artigo em Inglês | MEDLINE | ID: mdl-33667342

RESUMO

Perception improves by repeated practice with visual stimuli, a phenomenon known as visual perceptual learning (VPL). The interplay of attentional and neuromodulatory reward signals is hypothesized to cause these behavioral and associated neuronal changes, although VPL can occur without attention (i.e., task-irrelevant VPL). In addition, task-relevant VPL can be category-selective for simple attended oriented stimuli. Yet, it is unclear whether category-selective task-irrelevant VPL occurs and which brain centers mediate underlying forms of adult cortical plasticity. Here, we show that pairing subliminal complex visual stimuli (faces and bodies) with electrical microstimulation of the ventral tegmental area (VTA-EM) causes category-selective task-irrelevant VPL. These perceptual improvements are accompanied by fMRI signal changes in early and late visual and frontal areas, as well as the cerebellum, hippocampus, claustrum, and putamen. In conclusion, Pavlovian pairing of unattended complex stimuli with VTA-EM causes category-selective learning accompanied by changes of cortical and subcortical neural representations in macaques.


Assuntos
Atenção/fisiologia , Aprendizagem/fisiologia , Área Tegmentar Ventral/fisiologia , Córtex Visual/fisiologia , Percepção Visual/fisiologia , Animais , Estimulação Elétrica , Macaca , Imagem por Ressonância Magnética , Plasticidade Neuronal/fisiologia , Estimulação Luminosa , Área Tegmentar Ventral/diagnóstico por imagem , Córtex Visual/diagnóstico por imagem
9.
BMC Infect Dis ; 21(1): 259, 2021 Mar 12.
Artigo em Inglês | MEDLINE | ID: mdl-33711940

RESUMO

BACKGROUND: Plasmodium cynomolgi is a simian malaria parasite that has been reported as a naturally acquired human infection. The present study aims to systematically review reports on naturally acquired P. cynomolgi in humans, mosquitoes, and macaques to provide relevant data for pre-emptive surveillance and preparation in the event of an outbreak of zoonotic malaria in Southeast Asia. METHODS: The protocol of the systematic review was registered at PROSPERO with approval ID CRD42020203046. Three databases (Web of Science, Scopus, and MEDLINE) were searched for studies reporting the prevalence of P. cynomolgi infections in Southeast Asian countries between 1946 and 2020. The pooled prevalence or pooled proportion of P. cynomolgi parasitemia in humans, mosquitoes, and macaques was estimated using a random-effects model. Differences in the clinical characteristics of P. cynomolgi infections were also estimated using a random-effects model and presented as pooled odds ratios (ORs) or mean differences (MDs) with 95% confidence intervals (CIs). RESULTS: Thirteen studies reporting on the prevalence of naturally acquired P. cynomolgi in humans (3 studies, 21 cases), mosquitoes (3 studies, 28 cases), and macaques (7 studies, 334 cases) were included. The results demonstrated that the pooled proportion of naturally acquired P. cynomolgi in humans was 1% (95% CI, 0.1%, I2, 0%), while the pooled proportion of P. cynomolgi infecting mosquitoes was 18% (95% CI, 10-26%, I2, 32.7%). The pooled prevalence of naturally acquired P. cynomolgi in macaques was 47% (95% CI, 27-67%, I2, 98.3%). Most of the cases of naturally acquired P. cynomolgi in humans were reported in Cambodia (62%) and Malaysia (38%), while cases of P. cynomolgi in macaques were reported in Malaysia (35.4%), Singapore (23.2%), Indonesia (17.3%), Philippines (8.5%), Laos (7.93%), and Cambodia (7.65%). Cases of P. cynomolgi in mosquitoes were reported in Vietnam (76.9%) and Malaysia (23.1%). CONCLUSIONS: This study demonstrated the occurrence of naturally acquired P. cynomolgi infection in humans, mosquitoes, and macaques. Further studies of P. cynomolgi in asymptomatic human cases in areas where vectors and natural hosts are endemic are extensively needed if human infections with P. cynomolgi do become public health problems.


Assuntos
Culicidae/parasitologia , Macaca/parasitologia , Malária/diagnóstico , Plasmodium cynomolgi/isolamento & purificação , Animais , Ásia Sudeste/epidemiologia , DNA de Protozoário/metabolismo , Humanos , Malária/epidemiologia , Razão de Chances , Plasmodium cynomolgi/genética , Prevalência
10.
Acta Trop ; 217: 105850, 2021 May.
Artigo em Inglês | MEDLINE | ID: mdl-33524385

RESUMO

Chronic opisthorchiasis caused by Opisthorchis viverrini (O. viverrini) adversely affects human health and is associated with a fatal bile duct cancer (cholangiocarcinoma). Although cats and dogs are known animal reservoir hosts of opisthorchiasis, there is limited information about whether other fish-eating animals are fluke reservoirs. Wetlands along Chi River of Thailand have abundant intermediate host snails and fish for O. viverrini and diverse other animal species. This led to our investigation into whether other fish-eating animals can also become infected and be alternate reservoir hosts for human opisthorchiasis. Our preliminary study focused on the O. viverrini infection status of crab-eating or long-tailed macaques roaming in Kosumpi National Forest Park in Chi River Basin, Kosumpisai District of Mahasarakam Province, and rodents, small residential mammals and fish-eating birds living in Lawa wetland complex of Khon Kaen Province. Fecal samples of each animal were collected and modified formalin ether concentration technique was applied to identify infections. Additionally, participatory epidemiology was used to retrieve information from local communities on opisthorchiasis transmission in these animals. No O. viverrini infection was found in any fecal samples suggesting that monkeys, rodents, small residential mammals and birds in these two wetlands probably do not serve as alternate reservoir hosts of O. viverrini.


Assuntos
Aves/parasitologia , Macaca/parasitologia , Opistorquíase/epidemiologia , Opisthorchis , Roedores/parasitologia , Animais , Gatos/parasitologia , Pesquisa Participativa Baseada na Comunidade , DNA de Protozoário , Reservatórios de Doenças/parasitologia , Cães/parasitologia , Estudos Epidemiológicos , Fezes/parasitologia , Humanos , Fígado/parasitologia , Óvulo/classificação , Contagem de Ovos de Parasitas , Reação em Cadeia da Polimerase , Prevalência , Tailândia/epidemiologia
11.
Nat Commun ; 12(1): 1282, 2021 02 24.
Artigo em Inglês | MEDLINE | ID: mdl-33627642

RESUMO

Natural killer (NK) cells play a critical understudied role during HIV infection in tissues. In a natural host of SIV, the African green monkey (AGM), NK cells mediate a strong control of SIVagm infection in secondary lymphoid tissues. We demonstrate that SIVagm infection induces the expansion of terminally differentiated NKG2alow NK cells in secondary lymphoid organs displaying an adaptive transcriptional profile and increased MHC-E-restricted cytotoxicity in response to SIV Env peptides while expressing little IFN-γ. Such NK cell differentiation was lacking in SIVmac-infected macaques. Adaptive NK cells displayed no increased NKG2C expression. This study reveals a previously unknown profile of NK cell adaptation to a viral infection, thus accelerating strategies toward NK-cell directed therapies and viral control in tissues.


Assuntos
Células Matadoras Naturais/metabolismo , Linfonodos/metabolismo , Subfamília C de Receptores Semelhantes a Lectina de Células NK/metabolismo , Algoritmos , Animais , Linfócitos T CD4-Positivos/citologia , Linfócitos T CD4-Positivos/metabolismo , Diferenciação Celular/genética , Diferenciação Celular/fisiologia , Chlorocebus aethiops , Feminino , Citometria de Fluxo , Imunofluorescência , Humanos , Células K562 , Células Matadoras Naturais/citologia , Tecido Linfoide/citologia , Tecido Linfoide/metabolismo , Macaca , Masculino , Síndrome de Imunodeficiência Adquirida dos Símios/imunologia , Vírus da Imunodeficiência Símia/imunologia , Vírus da Imunodeficiência Símia/patogenicidade , Transcriptoma/genética
12.
Nat Commun ; 12(1): 894, 2021 02 09.
Artigo em Inglês | MEDLINE | ID: mdl-33563989

RESUMO

Prefrontal cortex is critical for cognition. Although much is known about the representation of cognitive variables in the prefrontal cortex, much less is known about the spatio-temporal neural dynamics that underlie cognitive operations. In the present study, we examined information timing and flow across the lateral prefrontal cortex (LPFC), while monkeys carried out a two-armed bandit reinforcement learning task in which they had to learn to select rewarding actions or rewarding objects. When we analyzed signals independently within subregions of the LPFC, we found a task-specific, caudo-rostral gradient in the strength and timing of signals related to chosen objects and chosen actions. In addition, when we characterized information flow among subregions, we found that information flow from action to object representations was stronger from the dorsal to ventral LPFC, and information flow from object to action representations was stronger from the ventral to dorsal LPFC. The object to action effects were more pronounced in object blocks, and also reflected learning specifically in these blocks. These results suggest anatomical segregation followed by the rapid integration of information within the LPFC.


Assuntos
Comportamento de Escolha/fisiologia , Córtex Pré-Frontal/fisiologia , Recompensa , Animais , Mapeamento Encefálico , Aprendizagem , Macaca , Modelos Neurológicos , Neurônios/fisiologia , Córtex Pré-Frontal/citologia , Tempo de Reação/fisiologia , Reforço Psicológico
13.
Immunity ; 54(3): 542-556.e9, 2021 03 09.
Artigo em Inglês | MEDLINE | ID: mdl-33631118

RESUMO

A combination of vaccination approaches will likely be necessary to fully control the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) pandemic. Here, we show that modified vaccinia Ankara (MVA) vectors expressing membrane-anchored pre-fusion stabilized spike (MVA/S) but not secreted S1 induced strong neutralizing antibody responses against SARS-CoV-2 in mice. In macaques, the MVA/S vaccination induced strong neutralizing antibodies and CD8+ T cell responses, and conferred protection from SARS-CoV-2 infection and virus replication in the lungs as early as day 2 following intranasal and intratracheal challenge. Single-cell RNA sequencing analysis of lung cells on day 4 after infection revealed that MVA/S vaccination also protected macaques from infection-induced inflammation and B cell abnormalities and lowered induction of interferon-stimulated genes. These results demonstrate that MVA/S vaccination induces neutralizing antibodies and CD8+ T cells in the blood and lungs and is a potential vaccine candidate for SARS-CoV-2.


Assuntos
/imunologia , Vetores Genéticos/genética , Vacinas de DNA/imunologia , Vírus Vaccinia/genética , Animais , Anticorpos Neutralizantes/imunologia , Anticorpos Antivirais/imunologia , Antígenos Virais/genética , Antígenos Virais/imunologia , /patologia , /genética , Modelos Animais de Doenças , Expressão Gênica , Ordem dos Genes , Imunofenotipagem , Pulmão/imunologia , Pulmão/patologia , Pulmão/virologia , Macaca , Macrófagos Alveolares/imunologia , Macrófagos Alveolares/metabolismo , Macrófagos Alveolares/patologia , Camundongos , Glicoproteína da Espícula de Coronavírus/genética , Glicoproteína da Espícula de Coronavírus/imunologia , Subpopulações de Linfócitos T/imunologia , Subpopulações de Linfócitos T/metabolismo , Vacinação/métodos , Vacinas de DNA/genética
14.
PLoS Negl Trop Dis ; 15(1): e0009110, 2021 01.
Artigo em Inglês | MEDLINE | ID: mdl-33493205

RESUMO

Plasmodium knowlesi is a simian malaria parasite currently recognized as the fifth causative agent of human malaria. Recently, naturally acquired P. cynomolgi infection in humans was also detected in Southeast Asia. The main reservoir of both parasites is the long-tailed and pig-tailed macaques, which are indigenous in this region. Due to increased urbanization and changes in land use, there has been greater proximity and interaction between the long-tailed macaques and the general population in Singapore. As such, this study aims to determine the prevalence of simian malaria parasites in local macaques to assess the risk of zoonosis to the general human population. Screening for the presence of malaria parasites was conducted on blood samples from 660 peridomestic macaques collected between Jan 2008 and Mar 2017, and 379 wild macaques collected between Mar 2009 and Mar 2017, using a Pan-Plasmodium-genus specific PCR. Positive samples were then screened using a simian Plasmodium species-specific nested PCR assay to identify the species of parasites (P. knowlesi, P. coatneyi, P. fieldi, P. cynomolgi, and P. inui) present. All the peridomestic macaques sampled were tested negative for malaria, while 80.5% of the 379 wild macaques were infected. All five simian Plasmodium species were detected; P. cynomolgi being the most prevalent (71.5%), followed by P. knowlesi (47.5%), P. inui (42.0%), P. fieldi (32.5%), and P. coatneyi (28.5%). Co-infection with multiple species of Plasmodium parasites was also observed. The study revealed that Singapore's wild long-tailed macaques are natural hosts of the five simian malaria parasite species, while no malaria was detected in all peridomestic macaques tested. Therefore, the risk of simian malaria transmission to the general human population is concluded to be low. However, this can be better demonstrated with the incrimination of the vectors of simian malaria parasites in Singapore.


Assuntos
Macaca/parasitologia , Malária/epidemiologia , Doenças dos Macacos/epidemiologia , Doenças dos Macacos/parasitologia , Zoonoses/epidemiologia , Animais , Macaca fascicularis/parasitologia , Plasmodium , Plasmodium knowlesi , Reação em Cadeia da Polimerase , Prevalência , Singapura/epidemiologia
16.
Neuroimage ; 228: 117692, 2021 03.
Artigo em Inglês | MEDLINE | ID: mdl-33385546

RESUMO

Diffusion MRI (dMRI) represents one of the few methods for mapping brain fiber orientations non-invasively. Unfortunately, dMRI fiber mapping is an indirect method that relies on inference from measured diffusion patterns. Comparing dMRI results with other modalities is a way to improve the interpretation of dMRI data and help advance dMRI technologies. Here, we present methods for comparing dMRI fiber orientation estimates with optical imaging of fluorescently labeled neurofilaments and vasculature in 3D human and primate brain tissue cuboids cleared using CLARITY. The recent advancements in tissue clearing provide a new opportunity to histologically map fibers projecting in 3D, which represents a captivating complement to dMRI measurements. In this work, we demonstrate the capability to directly compare dMRI and CLARITY in the same human brain tissue and assess multiple approaches for extracting fiber orientation estimates from CLARITY data. We estimate the three-dimensional neuronal fiber and vasculature orientations from neurofilament and vasculature stained CLARITY images by calculating the tertiary eigenvector of structure tensors. We then extend CLARITY orientation estimates to an orientation distribution function (ODF) formalism by summing multiple sub-voxel structure tensor orientation estimates. In a sample containing part of the human thalamus, there is a mean angular difference of 19o±15o between the primary eigenvectors of the dMRI tensors and the tertiary eigenvectors from the CLARITY neurofilament stain. We also demonstrate evidence that vascular compartments do not affect the dMRI orientation estimates by showing an apparent lack of correspondence (mean angular difference = 49o±23o) between the orientation of the dMRI tensors and the structure tensors in the vasculature stained CLARITY images. In a macaque brain dataset, we examine how the CLARITY feature extraction depends on the chosen feature extraction parameters. By varying the volume of tissue over which the structure tensor estimates are derived, we show that orientation estimates are noisier with more spurious ODF peaks for sub-voxels below 30 µm3 and that, for our data, the optimal gray matter sub-voxel size is between 62.5 µm3 and 125 µm3. The example experiments presented here represent an important advancement towards robust multi-modal MRI-CLARITY comparisons.


Assuntos
Encéfalo/anatomia & histologia , Substância Cinzenta/anatomia & histologia , Processamento de Imagem Assistida por Computador/métodos , Imagem Multimodal/métodos , Neuroimagem/métodos , Substância Branca/anatomia & histologia , Animais , Imagem de Difusão por Ressonância Magnética/métodos , Humanos , Imageamento Tridimensional/métodos , Macaca , Imagem Óptica/métodos
17.
Zool Res ; 42(1): 3-13, 2021 Jan 18.
Artigo em Inglês | MEDLINE | ID: mdl-33410309

RESUMO

Phylogenetic relationships within the sinica-group of macaques based on morphological, behavioral, and molecular characteristics have remained controversial. The Nepal population of Assam macaques ( Macaca assamensis) (NPAM), the westernmost population of the species, is morphologically distinct but has never been used in phylogenetic analyses. Here, the phylogenetic relationship of NPAM with other congeners was tested using multiple mitochondrial and Y-chromosomal loci. The divergence times and evolutionary genetic distances among macaques were also estimated. Results revealed two major mitochondrial DNA clades of macaques under the sinica-group: the first clade included M. thibetana, M. sinica, and eastern subspecies of Assam macaque ( M. assamensis assamensis); the second clade included M. radiata together with species from the eastern and central Himalaya, namely, M. leucogenys, M. munzala, and NPAM. Among the second-clade species, NPAM was the first to diverge from the other members of the clade around 1.9 million years ago. Our results revealed that NPAM is phylogenetically distinct from the eastern Assam macaques and closer to other species and hence may represent a separate species. Because of its phylogenetic distinctiveness, isolated distribution, and small population size, the Nepal population of sinica-group macaques warrants detailed taxonomic revision and high conservation priority.


Assuntos
Distribuição Animal , Evolução Biológica , Conservação dos Recursos Naturais , Macaca/genética , Filogenia , Animais , DNA Mitocondrial/genética , Feminino , Macaca/classificação , Macaca/fisiologia , Masculino , Tipagem de Sequências Multilocus , Nepal , RNA Ribossômico 16S/genética , Especificidade da Espécie , Fatores de Tempo , Cromossomo Y
18.
Behav Processes ; 185: 104317, 2021 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-33417930

RESUMO

Animals show various forms of behavioral thermoregulation to minimize cold stress. Given that higher dominance rank is often associated with increased fitness in group-living animals, higher-ranking individuals may also benefit from better access to thermally optimal spatial positions within huddles. This study examined the association between dominance rank and the potential thermoregulatory benefits of huddling behavior in Japanese macaques (Macaca fuscata) inhabiting Shodoshima Island, which form exceptionally large huddles. I photographed monkey huddles, and analyzed the number of individuals that males were in contact with and males' spatial positons in huddles. Higher-ranking males were significantly more likely to be in contact with larger numbers of individuals in huddles. Higher-ranking males occupied non-peripheral positions in huddles more often than lower-ranking males, which put them in contact with larger numbers of individuals. These results suggest that high dominance rank may confer potential thermal advantages on male Japanese macaques. The mechanism for this is likely that the highest-ranking male often intrude in already-formed huddles, although such behaviors of males were not quantitatively assessed. This study contributes to a better understanding of the mechanisms of cold adaptation in relation to dominance rank in group-living animals.


Assuntos
Macaca fuscata , Predomínio Social , Animais , Regulação da Temperatura Corporal , Haplorrinos , Macaca , Masculino
19.
Proc Natl Acad Sci U S A ; 118(3)2021 01 19.
Artigo em Inglês | MEDLINE | ID: mdl-33431673

RESUMO

Deep neural networks currently provide the best quantitative models of the response patterns of neurons throughout the primate ventral visual stream. However, such networks have remained implausible as a model of the development of the ventral stream, in part because they are trained with supervised methods requiring many more labels than are accessible to infants during development. Here, we report that recent rapid progress in unsupervised learning has largely closed this gap. We find that neural network models learned with deep unsupervised contrastive embedding methods achieve neural prediction accuracy in multiple ventral visual cortical areas that equals or exceeds that of models derived using today's best supervised methods and that the mapping of these neural network models' hidden layers is neuroanatomically consistent across the ventral stream. Strikingly, we find that these methods produce brain-like representations even when trained solely with real human child developmental data collected from head-mounted cameras, despite the fact that these datasets are noisy and limited. We also find that semisupervised deep contrastive embeddings can leverage small numbers of labeled examples to produce representations with substantially improved error-pattern consistency to human behavior. Taken together, these results illustrate a use of unsupervised learning to provide a quantitative model of a multiarea cortical brain system and present a strong candidate for a biologically plausible computational theory of primate sensory learning.


Assuntos
Rede Nervosa/fisiologia , Redes Neurais de Computação , Neurônios/fisiologia , Reconhecimento Visual de Modelos/fisiologia , Córtex Visual/fisiologia , Animais , Criança , Conjuntos de Dados como Assunto , Humanos , Macaca/fisiologia , Rede Nervosa/anatomia & histologia , Aprendizado de Máquina não Supervisionado , Córtex Visual/anatomia & histologia
20.
PLoS Comput Biol ; 17(1): e1008564, 2021 01.
Artigo em Inglês | MEDLINE | ID: mdl-33471814

RESUMO

Experimental Zika virus infection in non-human primates results in acute viral load dynamics that can be well-described by mathematical models. The inoculum dose that would be received in a natural infection setting is likely lower than the experimental infections and how this difference affects the viral dynamics and immune response is unclear. Here we study a dataset of experimental infection of non-human primates with a range of doses of Zika virus. We develop new models of infection incorporating both an innate immune response and viral interference with that response. We find that such a model explains the data better than models with no interaction between virus and the immune response. We also find that larger inoculum doses lead to faster dynamics of infection, but approximately the same total amount of viral production.


Assuntos
Imunidade Inata/imunologia , Interferência Viral , Infecção por Zika virus , Zika virus , Animais , Biologia Computacional , Interações Hospedeiro-Patógeno/imunologia , Interações Hospedeiro-Patógeno/fisiologia , Macaca , Modelos Biológicos , Interferência Viral/imunologia , Interferência Viral/fisiologia , Carga Viral/imunologia , Carga Viral/fisiologia , Zika virus/imunologia , Zika virus/patogenicidade , Zika virus/fisiologia , Infecção por Zika virus/imunologia , Infecção por Zika virus/virologia
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