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1.
Nat Immunol ; 23(8): 1256-1272, 2022 08.
Artigo em Inglês | MEDLINE | ID: mdl-35902638

RESUMO

The recombination-activating genes (RAG) 1 and 2 are indispensable for diversifying the primary B cell receptor repertoire and pruning self-reactive clones via receptor editing in the bone marrow; however, the impact of RAG1/RAG2 on peripheral tolerance is unknown. Partial RAG deficiency (pRD) manifesting with late-onset immune dysregulation represents an 'experiment of nature' to explore this conundrum. By studying B cell development and subset-specific repertoires in pRD, we demonstrate that reduced RAG activity impinges on peripheral tolerance through the generation of a restricted primary B cell repertoire, persistent antigenic stimulation and an inflammatory milieu with elevated B cell-activating factor. This unique environment gradually provokes profound B cell dysregulation with widespread activation, remarkable extrafollicular maturation and persistence, expansion and somatic diversification of self-reactive clones. Through the model of pRD, we reveal a RAG-dependent 'domino effect' that impacts stringency of tolerance and B cell fate in the periphery.


Assuntos
Linfócitos B , Proteínas de Ligação a DNA , Proteínas de Homeodomínio , Proteínas Nucleares , Diferenciação Celular , Proteínas de Ligação a DNA/deficiência , Proteínas de Ligação a DNA/genética , Proteínas de Homeodomínio/genética , Humanos , Tolerância Imunológica , Contagem de Linfócitos , Proteínas Nucleares/deficiência
2.
Int J Health Plann Manage ; 39(4): 1097-1112, 2024 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-38373041

RESUMO

This paper describes and compares the integration of cross-sector actors' participation into the governance of two local health councils, one located in Salvador de Bahia (Brazil) and the other in the Canary Islands (Spain). Based on the cross-national comparative research conducted as part of a doctoral thesis, a qualitative design based on secondary data analysis was proposed on the three stages of the organisational integration process of participation. We used information from individual semi-structured interviews (n = 70), situational observation, focus groups, literature review, and field notes to understand participatory processes of networking between multiple cross-sector actors and to show how such processes might be associated with innovative practices. For these innovations to be successfully implemented, stakeholders need to acquire adequate competencies in cross-sector collaboration, enabling them to learn about new organisational practices and to adapt the network of actors to the often unpredictable influences of contextual factors.


Assuntos
Grupos Focais , Espanha , Brasil , Humanos , Entrevistas como Assunto , Pesquisa Qualitativa , Governo Local , Atenção à Saúde/organização & administração , Participação dos Interessados
3.
Sensors (Basel) ; 24(5)2024 Feb 22.
Artigo em Inglês | MEDLINE | ID: mdl-38474940

RESUMO

The effects of the use of reduced feedback frequencies on motor learning remain controversial in the scientific literature. At present, there is still controversy about the guidance hypothesis, with some works supporting it and others contradicting it. To shed light on this topic, an experiment was conducted with four groups, each with different feedback frequencies (0%, 33%, 67%, and 100%), which were evaluated three times (pre-test, post-test, and retention) during a postural control task. In addition, we tested whether there was a transfer in performance to another similar task involving postural control. As a result, only the 67% feedback group showed an improvement in their task performance in the post-test and retention evaluations. Nevertheless, neither group showed differences in motor transfer performance compared to another postural control task. In conclusion, the findings of this paper corroborate the hypothesis of guidance and suggest that the use of a reduced frequency of 67% is a better option for improving motor learning than options that offer feedback at a lower frequency, at all trials or not at all.


Assuntos
Aprendizagem , Equilíbrio Postural , Humanos , Adulto Jovem , Retroalimentação , Análise e Desempenho de Tarefas , Análise de Variância , Destreza Motora
5.
Plant J ; 109(4): 804-815, 2022 02.
Artigo em Inglês | MEDLINE | ID: mdl-34797611

RESUMO

The leaf of a deciduous species completes its life cycle in a few months. During leaf maturation, osmolyte accumulation leads to a significant reduction of the turgor loss point (ΨTLP ), a known marker for stomatal closure. Here we exposed two grapevine cultivars to drought at three different times during the growing season to explore if the seasonal decrease in leaf ΨTLP influences the stomatal response to drought. The results showed a significant seasonal shift in the response of stomatal conductance to stem water potential (gs ~Ψstem ), demonstrating that grapevines become increasingly tolerant to low Ψstem as the season progresses in coordination with the decrease in ΨTLP . We also used the SurEau hydraulic model to demonstrate a direct link between osmotic adjustment and the plasticity of gs ~Ψstem . To understand the possible advantages of gs ~Ψstem plasticity, we incorporated a seasonally dynamic leaf osmotic potential into the model that simulated stomatal conductance under several water availabilities and climatic scenarios. The model demonstrated that a seasonally dynamic stomatal closure threshold results in trade-offs: it reduces the time to turgor loss under sustained long-term drought, but increases overall gas exchange particularly under seasonal shifts in temperature and stochastic water availability. A projected hotter future is expected to lower the increase in gas exchange that plants gain from the seasonal shift in gs ~Ψstem . These findings show that accounting for dynamic stomatal regulation is critical for understanding drought tolerance.


Assuntos
Secas , Estômatos de Plantas/metabolismo , Estações do Ano , Água/fisiologia , Adaptação Fisiológica/fisiologia , Osmose/fisiologia , Pressão Osmótica , Folhas de Planta/fisiologia , Fenômenos Fisiológicos Vegetais , Vitis/fisiologia
6.
Fungal Genet Biol ; 166: 103792, 2023 05.
Artigo em Inglês | MEDLINE | ID: mdl-36996931

RESUMO

Polyamines are ubiquitous small organic cations, and their roles as regulators of several cellular processes are widely recognized. They are implicated in the key stages of the fungal life cycle. Ustilago maydis is a phytopathogenic fungus, the causal agent of common smut of maize and a model system to understand dimorphism and virulence. U. maydis grows in yeast form at pH 7 and it can develop its mycelial form in vitro at pH 3. Δodc mutants that are unable to synthesize polyamines, grow as yeast at pH 3 with a low putrescine concentration, and to complete its dimorphic transition high putrescine concentration is require. Δspd mutants require spermidine to grow and cannot form mycelium at pH 3. In this work, the increased expression of the mating genes, mfa1 and mfa2, on Δodc mutants, was related to high putrescine concentration. Global gene expression analysis comparisons of Δodc and Δspd U. maydis mutants indicated that 2,959 genes were differentially expressed in the presence of exogenous putrescine at pH 7 and 475 genes at pH 3. While, in Δspd mutant, the expression of 1,426 genes was affected by exogenous spermine concentration at pH 7 and 11 genes at pH 3. Additionally, we identified 28 transcriptional modules with correlated expression during seven tested conditions: mutant genotype, morphology (yeast, and mycelium), pH, and putrescine or spermidine concentration. Furthermore, significant differences in transcript levels were noted for genes in modules relating to pH and genotype genes involved in ribosome biogenesis, mitochondrial oxidative phosphorylation, N-glycan synthesis, and Glycosylphosphatidylinositol (GPI)-anchor. In summary, our results offer a valuable tool for the identification of potential factors involved in phenomena related to polyamines and dimorphism.


Assuntos
Poliaminas , Proteínas de Saccharomyces cerevisiae , Poliaminas/metabolismo , Putrescina/metabolismo , Putrescina/farmacologia , Espermidina/metabolismo , Ornitina Descarboxilase/genética , Ornitina Descarboxilase/metabolismo , Espermidina Sintase/genética , Saccharomyces cerevisiae/genética , Caracteres Sexuais , Expressão Gênica , Lipoproteínas/genética , Feromônios , Proteínas de Saccharomyces cerevisiae/genética
7.
Plant Physiol ; 190(3): 1673-1686, 2022 10 27.
Artigo em Inglês | MEDLINE | ID: mdl-35946780

RESUMO

Climate change is challenging the resilience of grapevine (Vitis), one of the most important crops worldwide. Adapting viticulture to a hotter and drier future will require a multifaceted approach including the breeding of more drought-tolerant genotypes. In this study, we focused on plant hydraulics as a multi-trait system that allows the plant to maintain hydraulic integrity and gas exchange rates longer under drought. We quantified a broad range of drought-related traits within and across Vitis species, created in silico libraries of trait combinations, and then identified drought tolerant trait syndromes. By modeling the maintenance of hydraulic integrity of current cultivars and the drought tolerant trait syndromes, we identified elite ideotypes that increased the amount of time they could experience drought without leaf hydraulic failure. Generally, elites exhibited a trait syndrome with lower stomatal conductance, earlier stomatal closure, and a larger hydraulic safety margin. We demonstrated that, when compared with current cultivars, elite ideotypes have the potential to decrease the risk of hydraulic failure across wine regions under future climate scenarios. This study reveals the syndrome of traits that can be leveraged to protect grapevine from experiencing hydraulic failure under drought and increase drought tolerance.


Assuntos
Vitis , Água , Síndrome , Melhoramento Vegetal , Secas , Folhas de Planta/genética , Vitis/genética
8.
PLoS Comput Biol ; 18(4): e1010019, 2022 04.
Artigo em Inglês | MEDLINE | ID: mdl-35377875

RESUMO

Microfluidic capacities for both recreating and monitoring cell cultures have opened the door to the use of Data Science and Machine Learning tools for understanding and simulating tumor evolution under controlled conditions. In this work, we show how these techniques could be applied to study Glioblastoma, the deadliest and most frequent primary brain tumor. In particular, we study Glioblastoma invasion using the recent concept of Physically-Guided Neural Networks with Internal Variables (PGNNIV), able to combine data obtained from microfluidic devices and some physical knowledge governing the tumor evolution. The physics is introduced in the network structure by means of a nonlinear advection-diffusion-reaction partial differential equation that models the Glioblastoma evolution. On the other hand, multilayer perceptrons combined with a nodal deconvolution technique are used for learning the go or grow metabolic behavior which characterises the Glioblastoma invasion. The PGNNIV is here trained using synthetic data obtained from in silico tests created under different oxygenation conditions, using a previously validated model. The unravelling capacity of PGNNIV enables discovering complex metabolic processes in a non-parametric way, thus giving explanatory capacity to the networks, and, as a consequence, surpassing the predictive power of any parametric approach and for any kind of stimulus. Besides, the possibility of working, for a particular tumor, with different boundary and initial conditions, permits the use of PGNNIV for defining virtual therapies and for drug design, thus making the first steps towards in silico personalised medicine.


Assuntos
Glioblastoma , Glioblastoma/patologia , Humanos , Aprendizado de Máquina , Processos Neoplásicos , Redes Neurais de Computação , Física
9.
Health Expect ; 26(2): 567-578, 2023 04.
Artigo em Inglês | MEDLINE | ID: mdl-36585793

RESUMO

INTRODUCTION: Scalp cooling (SC) aims to prevent chemotherapy-induced alopecia. The goal of this systematic review is to tackle ethical, legal, organizational and social issues related to SC. METHODS: A critical appraisal of the literature was carried out using a systematic review design. MEDLINE, Embase and Web of Science databases were searched up until 2 June 2021. Studies addressing these aspects in English or Spanish were considered. Representatives of both patient associations and professional scientific societies related to the topic participated in the design of the protocol and the review of the findings. RESULTS: A total of 17 studies were included. Articles were critically appraised using the MMAT and SANRA. Findings were organized into four categories: (1) ethical aspects focused on equal access, gender equity and doctor-patient communication supported by Patient Decision Aids (PtDAs); (2) patient perspective and acceptability; (3) professional perspective and acceptability; (4) organizational aspects focused on accessibility and feasibility. CONCLUSION: Cancer patients' expectations when using SC need to be adjusted to reduce the potential distress associated with hair loss. PtDAs could help patients clarify their values and preferences regarding SC. Equal access to technology should be guaranteed. PATIENT OR PUBLIC CONTRIBUTION: In this systematic review, the representatives of the patient associations (Ms. María Luz Amador Muñoz of the Spanish Association Against Cancer [AECC] and Ms. Catiana Martinez Cánovas of the Spanish Breast Cancer Federation [FECMA]) participated in the review of the study protocol, as well as in the results, discussion and conclusions, making their contributions. In the type of design of these studies (systematic reviews), it is not usual to have the direct participation of patients, but in this one, we have done so, as it is a systematic review that is part of a report of the Spanish Network of Health Technology Assessment Agencies (ETS).


Assuntos
Antineoplásicos , Neoplasias da Mama , Humanos , Feminino , Couro Cabeludo , Neoplasias da Mama/tratamento farmacológico , Alopecia/induzido quimicamente , Alopecia/prevenção & controle , Comunicação , Antineoplásicos/efeitos adversos
10.
BMC Public Health ; 23(1): 992, 2023 05 29.
Artigo em Inglês | MEDLINE | ID: mdl-37248460

RESUMO

BACKGROUND: Prostate cancer is the leading cause of cancer death in Ecuadorian men. However, there is a lack of information regarding the evolution of prostate cancer mortality rates in Ecuador and its regions in the last few decades. OBJECTIVE: The aim of this study was to report prostate cancer mortality rates in Ecuador and its geographical areas and observe the evolution of these rates between 2004 and 2019. METHODS: An observational ecological study was conducted, analysing data for prostate cancer deaths from 2004 to 2019 in Ecuador. Age standardized mortality rates (ASMR) were calculated per 100,000 men using the world standard population with the direct method proposed by SEGI. Joinpoint regression analysis was performed to examine mortality trends. We used a Cluster Map to explore relationships among regions between 2015 and 2019. RESULTS: Ecuador reported 13,419 deaths by prostate cancer between 2004 and 2019, with the Coastal region accounting for 49.8% of the total deaths. The mean age at death was 79 years (± 10 years), 91.7% were elderly (more than 65 years old) and had primary education (53%). Deaths by prostate cancer were more frequently reported among mestizos (81.4%). There were no significant variations in these percentages in Ecuador and its regions during the study period. Carchi province had the highest mortality rate in 2005 and 2019 (> 13 deaths per 100,000). Heterogeneity in the evolution of mortality rates was reported among the provinces of Ecuador. Azuay decreased in the first few years, and then increased from 2010 to 2019, whereas Guayas and Pichincha decreased throughout the whole period. CONCLUSION: Although prostate cancer mortality rates in Ecuador have remained stable over the past few decades, there are significant disparities among the different regions. These findings suggest the need for the development of national and provincial registration measures, integrated healthcare actions, and targeted interventions to reduce the burden of prostate cancer in the Ecuadorian population.


Assuntos
Neoplasias da Próstata , Masculino , Humanos , Idoso , Equador/epidemiologia , Análise de Regressão , Mortalidade
11.
Int J Mol Sci ; 24(22)2023 Nov 13.
Artigo em Inglês | MEDLINE | ID: mdl-38003442

RESUMO

This study explores the hysteresis phenomenon in DPPC (1,2-dipalmitoyl-sn-glycero-3-phosphocholine) monolayers, considering several variables, including temperature, compression and expansion rates, residence time, and subphase content. The investigation focuses on analyzing the influence of these variables on key indicators such as the π-A isotherm curve, loop area, and compression modulus. By employing the Langmuir-Blodgett technique, the findings reveal that all the examined factors significantly affect the aforementioned parameters. Notably, the hysteresis loop, representing dissipated energy, provides valuable insights into the monolayer's viscoelasticity, molecular packing, phase transition changes, and resistance during the isocycle process. These findings contribute to a comprehensive understanding of the structural and dynamic properties of DPPC monolayers, offering insights into their behavior under varying conditions. Moreover, the knowledge gained from this study can aid in the development of precise models and strategies for controlling and manipulating monolayer properties, with potential applications in drug delivery systems, surface coatings, as well as further investigation into air penetration into alveoli and the blinking mechanism.


Assuntos
1,2-Dipalmitoilfosfatidilcolina , Glicerilfosforilcolina , Propriedades de Superfície , 1,2-Dipalmitoilfosfatidilcolina/química , Temperatura
12.
Int J Mol Sci ; 24(15)2023 Jul 30.
Artigo em Inglês | MEDLINE | ID: mdl-37569585

RESUMO

In healthy tissues, cells are in mechanical homeostasis. During cancer progression, this equilibrium is disrupted. Cancer cells alter their mechanical phenotype to a softer and more fluid-like one than that of healthy cells. This is connected to cytoskeletal remodeling, changed adhesion properties, faster cell proliferation and increased cell motility. In this work, we investigated the mechanical properties of breast cancer cells representative of different breast cancer subtypes, using MCF-7, tamoxifen-resistant MCF-7, MCF10A and MDA-MB-231 cells. We derived viscoelastic properties from atomic force microscopy force spectroscopy measurements and showed that the mechanical properties of the cells are associated with cancer cell malignancy. MCF10A are the stiffest and least fluid-like cells, while tamoxifen-resistant MCF-7 cells are the softest ones. MCF-7 and MDA-MB-231 show an intermediate mechanical phenotype. Confocal fluorescence microscopy on cytoskeletal elements shows differences in actin network organization, as well as changes in focal adhesion localization. These findings provide further evidence of distinct changes in the mechanical properties of cancer cells compared to healthy cells and add to the present understanding of the complex alterations involved in tumorigenesis.


Assuntos
Neoplasias da Mama , Citoesqueleto , Humanos , Feminino , Linhagem Celular Tumoral , Citoesqueleto/metabolismo , Células MCF-7 , Actinas/metabolismo , Tamoxifeno/farmacologia , Tamoxifeno/metabolismo , Neoplasias da Mama/metabolismo , Microscopia de Força Atômica/métodos
13.
Int J Mol Sci ; 24(3)2023 Jan 30.
Artigo em Inglês | MEDLINE | ID: mdl-36768962

RESUMO

Stress-associated changes in the mechanical properties at the single-cell level of Escherichia coli (E. coli) cultures in bioreactors are still poorly investigated. In our study, we compared peptide-producing and non-producing BL21(DE3) cells in a fed-batch cultivation with tightly controlled process parameters. The cell growth, peptide content, and cell lysis were analysed, and changes in the mechanical properties were investigated using atomic force microscopy. Recombinant-tagged somatostatin-28 was expressed as soluble up to 197 ± 11 mg g-1. The length of both cultivated strains increased throughout the cultivation by up to 17.6%, with nearly constant diameters. The peptide-producing cells were significantly softer than the non-producers throughout the cultivation, and respective Young's moduli decreased by up to 57% over time. A minimum Young's modulus of 1.6 MPa was observed after 23 h of the fed-batch. Furthermore, an analysis of the viscoelastic properties revealed that peptide-producing BL21(DE3) appeared more fluid-like and softer than the non-producing reference. For the first time, we provide evidence that the physical properties (i.e., the mechanical properties) on the single-cell level are significantly influenced by the metabolic burden imposed by the recombinant peptide expression and C-limitation in bioreactors.


Assuntos
Reatores Biológicos , Escherichia coli , Proteínas Recombinantes/metabolismo , Ciclo Celular
14.
Int J Mol Sci ; 24(5)2023 Mar 01.
Artigo em Inglês | MEDLINE | ID: mdl-36902214

RESUMO

Acral melanoma (AM) is the most common melanoma in non-Caucasian populations, yet it remains largely understudied. As AM lacks the UV-radiation mutational signatures that characterize other cutaneous melanomas, it is considered devoid of immunogenicity and is rarely included in clinical trials assessing novel immunotherapeutic regimes aiming to recover the antitumor function of immune cells. We studied a Mexican cohort of melanoma patients from the Mexican Institute of Social Security (IMSS) (n = 38) and found an overrepresentation of AM (73.9%). We developed a multiparametric immunofluorescence technique coupled with a machine learning image analysis to evaluate the presence of conventional type 1 dendritic cells (cDC1) and CD8 T cells in the stroma of melanoma, two of the most relevant immune cell types for antitumor responses. We observed that both cell types infiltrate AM at similar and even higher levels than other cutaneous melanomas. Both melanoma types harbored programmed cell death protein 1 (PD-1+) CD8 T cells and PD-1 ligand (PD-L1+) cDC1s. Despite this, CD8 T cells appeared to preserve their effector function and expanding capacity as they expressed interferon-γ (IFN-γ) and KI-67. The density of cDC1s and CD8 T cells significantly decreased in advanced stage III and IV melanomas, supporting these cells' capacity to control tumor progression. These data also argue that AM could respond to anti-PD-1-PD-L1 immunotherapy.


Assuntos
Linfócitos T CD8-Positivos , Células Dendríticas , Linfócitos do Interstício Tumoral , Melanoma , Neoplasias Cutâneas , Pele , Humanos , Antígeno B7-H1/metabolismo , Linfócitos T CD8-Positivos/imunologia , Melanoma/imunologia , Melanoma/patologia , Neoplasias Cutâneas/imunologia , Neoplasias Cutâneas/patologia , Células Dendríticas/imunologia , Linfócitos do Interstício Tumoral/imunologia , Raios Ultravioleta , Exposição à Radiação , Pele/efeitos da radiação , Melanoma Maligno Cutâneo
15.
Medicina (Kaunas) ; 59(10)2023 10 20.
Artigo em Inglês | MEDLINE | ID: mdl-37893585

RESUMO

Background and Objectives: Venous thromboembolism (VTE) is common in cancer patients. Anticoagulant therapy with low-molecular-weight heparins (LMWHs) and direct oral anticoagulants (DOACs), such as dalteparin and apixaban, have demonstrated efficacy and safety. However, more comparative research of these drugs is still needed. This study aimed to synthesize evidence on the efficacy of apixaban compared to dalteparin in reducing recurrent VTE, major bleeding, and clinically relevant non-major bleeding associated with cancer. Materials and Methods: We systematically searched the PubMed, Scopus, Web of Science, Embase, Cochrane Library, and ClinicalTrials databases up to 5 January 2023, for randomized controlled trials comparing apixaban versus dalteparin as treatment for cancer-associated VTE. Five studies were included. Effects according to meta-analyses were reported as relative risks (RRs) and their 95% confidence intervals (CIs). Results: It was found that 33 of 734 (4.5%) patients treated with apixaban and 56 of 767 (7.3%) with dalteparin had recurrent VTE as the efficacy outcome (RR 0.49, 95% CI 0.15-1.58, I2 38%). Major bleeding occurred in 25 of 734 patients treated with apixaban (3.4%) and 27 of 767 with dalteparin (3.5%) (RR 1.29, 95% CI 0.31-5.27, I2 59%). Likewise, clinically relevant non-major bleeding occurred in 64 of 734 patients treated with apixaban (8.7%) and 46 of 767 (5.9%) with dalteparin (RR 1.52, 95% CI 1.05-2.19, I2 0%). Conclusions: Apixaban showed a lower risk of recurrent VTE than dalteparin in patients with cancer-associated VTE, albeit with no statistical difference. Statistical significance was observed for no major clinically relevant bleeding but not for major bleeding.


Assuntos
Neoplasias , Tromboembolia Venosa , Humanos , Dalteparina/efeitos adversos , Tromboembolia Venosa/tratamento farmacológico , Tromboembolia Venosa/etiologia , Anticoagulantes/efeitos adversos , Hemorragia/induzido quimicamente , Hemorragia/complicações , Neoplasias/complicações , Neoplasias/tratamento farmacológico
16.
J Neurosci ; 41(14): 3204-3221, 2021 04 07.
Artigo em Inglês | MEDLINE | ID: mdl-33648956

RESUMO

Learning the spatial layout of a novel environment is associated with dynamic activity changes in the hippocampus and in medial parietal areas. With advancing age, the ability to learn spatial environments deteriorates substantially but the underlying neural mechanisms are not well understood. Here, we report findings from a behavioral and a fMRI experiment where healthy human older and younger adults of either sex performed a spatial learning task in a photorealistic virtual environment (VE). We modeled individual learning states using a Bayesian state-space model and found that activity in retrosplenial cortex (RSC)/parieto-occipital sulcus (POS) and anterior hippocampus did not change systematically as a function learning in older compared with younger adults across repeated episodes in the environment. Moreover, effective connectivity analyses revealed that the age-related learning deficits were linked to an increase in hippocampal excitability. Together, these results provide novel insights into how human aging affects computations in the brain's navigation system, highlighting the critical role of the hippocampus.SIGNIFICANCE STATEMENT Key structures of the brain's navigation circuit are particularly vulnerable to the deleterious consequences of aging, and declines in spatial navigation are among the earliest indicators for a progression from healthy aging to neurodegenerative diseases. Our study is among the first to provide a mechanistic account about how physiological changes in the aging brain affect the formation of spatial knowledge. We show that neural activity in the aging hippocampus and medial parietal areas is decoupled from individual learning states across repeated episodes in a novel spatial environment. Importantly, we find that increased excitability of the anterior hippocampus might constitute a potential neural mechanism for cognitive mapping deficits in old age.


Assuntos
Envelhecimento/fisiologia , Mapeamento Encefálico/métodos , Cognição/fisiologia , Hipocampo/fisiologia , Aprendizagem Espacial/fisiologia , Realidade Virtual , Adulto , Idoso , Envelhecimento/psicologia , Feminino , Hipocampo/diagnóstico por imagem , Humanos , Imageamento por Ressonância Magnética/métodos , Masculino , Pessoa de Meia-Idade , Lobo Parietal/diagnóstico por imagem , Lobo Parietal/fisiologia , Desempenho Psicomotor/fisiologia , Navegação Espacial/fisiologia , Adulto Jovem
17.
Development ; 146(24)2019 12 16.
Artigo em Inglês | MEDLINE | ID: mdl-31740534

RESUMO

Embryonic stem cells (ESCs) exist in at least two states that transcriptionally resemble different stages of embryonic development. Naïve ESCs resemble peri-implantation stages and primed ESCs the pre-gastrulation epiblast. In mouse, primed ESCs give rise to definitive endoderm in response to the pathways downstream of Nodal and Wnt signalling. However, when these pathways are activated in naïve ESCs, they differentiate to a cell type resembling early primitive endoderm (PrE), the blastocyst-stage progenitor of the extra-embryonic endoderm. Here, we apply this context dependency to human ESCs, showing that activation of Nodal and Wnt signalling drives the differentiation of naïve pluripotent cells toward extra-embryonic PrE, or hypoblast, and these can be expanded as an in vitro model for naïve extra-embryonic endoderm (nEnd). Consistent with observations made in mouse, human PrE differentiation is dependent on FGF signalling in vitro, and we show that, by inhibiting FGF receptor signalling, we can simplify naïve pluripotent culture conditions, such that the inhibitor requirements closer resemble those used in mouse. The expandable nEnd cultures reported here represent stable extra-embryonic endoderm, or human hypoblast, cell lines.This article has an associated 'The people behind the papers' interview.


Assuntos
Endoderma/embriologia , Fator Inibidor de Leucemia/fisiologia , Ligantes da Sinalização Nodal/fisiologia , Células-Tronco Pluripotentes/fisiologia , Via de Sinalização Wnt/fisiologia , Animais , Células Cultivadas , Embrião de Mamíferos , Desenvolvimento Embrionário/genética , Células-Tronco Embrionárias/citologia , Células-Tronco Embrionárias/fisiologia , Endoderma/citologia , Endoderma/metabolismo , Regulação da Expressão Gênica no Desenvolvimento , Camadas Germinativas/citologia , Camadas Germinativas/fisiologia , Humanos , Fator Inibidor de Leucemia/metabolismo , Camundongos , Ligantes da Sinalização Nodal/metabolismo , Transdução de Sinais/fisiologia
18.
Langmuir ; 38(50): 15552-15558, 2022 12 20.
Artigo em Inglês | MEDLINE | ID: mdl-36484724

RESUMO

Bacterial cells survive in a wide range of different environments and actively tune their mechanical properties for purposes of growth, movement, division, and nutrition. In Gram-negative bacteria, the cell envelope with its outer membrane and peptidoglycan are the main determinants of mechanical properties and are common targets for the use of antibiotics. The study of bacterial mechanical properties has shown promise in elucidating a structure-function relationship in bacteria, connecting, shape, mechanics, and biochemistry. In this work, we study frequency and time-dependent viscoelastic properties of E. coli cells by atomic force microscopy (AFM). We perform force cycles, oscillatory microrheology, stress relaxation, and creep experiments, and use power law rheology models to fit the experimental results. All data sets could be fitted with the models and provided power law exponents of 0.01 to 0.1 while showing moduli in the range of a few MPa. We provide evidence for the interchangeability of the properties derived from these four different measurement approaches.


Assuntos
Antibacterianos , Escherichia coli , Elasticidade , Microscopia de Força Atômica/métodos , Membrana Celular , Viscosidade
19.
Int Microbiol ; 25(1): 17-26, 2022 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-34185162

RESUMO

The life cycle of Ustilago maydis involves alternation of a haploid saprophytic yeast-like stage and a dikaryotic hyphal virulent form. Under in vitro conditions, basidiocarps are formed. Analysis of the transcriptional network of basidiocarp formation revealed the possible involvement of a Tec transcription factor (Tec1, UMAG_02835) in the process. In some Ascomycota, Tec factors are involved in mycelial formation, pathogenesis, and interaction with other regulatory elements, but their role in Basidiomycota species is almost unknown. Accordingly, we proceeded to determine the role of this gene in U. maydis by its mutation. Tec1 was found to be a crucial factor for normal mating, basidiocarp development, and virulence, all of the functions related to the dikaryotic stage dependent of the b genes, whereas dimorphism and resistance to different stress conditions occurring in the haploid stage were not affected in tec1 mutants. The observation that mutants showed a low residual wild-type phenotype suggests the presence of a secondary mechanism that partially compensates the loss of Tec1.


Assuntos
Basidiomycota , Ustilago , Carpóforos , Proteínas Fúngicas/genética , Fatores de Transcrição/genética , Ustilago/genética , Virulência
20.
Sensors (Basel) ; 22(16)2022 Aug 16.
Artigo em Inglês | MEDLINE | ID: mdl-36015867

RESUMO

The information about where crops are distributed is useful for agri-environmental assessments, but is chiefly important for food security and agricultural policy managers. The quickness with which this information becomes available, especially over large areas, is important for decision makers. Methodologies have been proposed for the study of crops. Most of them require field survey for ground truth data and a single crop map is generated for the whole season at the end of the crop cycle and for the next crop cycle a new field survey is necessary. Here, we present models for recognizing maize (Zea mays L.), beans (Phaseolus vulgaris L.), and alfalfa (Medicago sativa L.) before the crop cycle ends without current-year field survey for ground truth data. The models were trained with an exhaustive field survey at plot level in a previous crop cycle. The field surveys begin since days before the emergence of crops to maturity. The algorithms used for classification were support vector machine (SVM) and bagged tree (BT), and the spectral information captured in the visible, red-edge, near infrared, and shortwave infrared regions bands of Sentinel 2 images was used. The models were validated within the next crop cycle each fifteen days before the mid-season. The overall accuracies range from 71.9% (38 days after the begin of cycle) to 87.5% (81 days after the begin cycle) and a kappa coefficient ranging from 0.53 at the beginning to 0.74 at mid-season.


Assuntos
Produtos Agrícolas , Zea mays , Agricultura , Algoritmos , Aprendizado de Máquina , Medicago sativa
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