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1.
Nat Protoc ; 2024 Jun 17.
Artigo em Inglês | MEDLINE | ID: mdl-38886530

RESUMO

Interactions between macromolecules, such as proteins and nucleic acids, are essential for cellular functions. Experimental methods can fail to provide all the information required to fully model biomolecular complexes at atomic resolution, particularly for large and heterogeneous assemblies. Integrative computational approaches have, therefore, gained popularity, complementing traditional experimental methods in structural biology. Here, we introduce HADDOCK2.4, an integrative modeling platform, and its updated web interface ( https://wenmr.science.uu.nl/haddock2.4 ). The platform seamlessly integrates diverse experimental and theoretical data to generate high-quality models of macromolecular complexes. The user-friendly web server offers automated parameter settings, access to distributed computing resources, and pre- and post-processing steps that enhance the user experience. To present the web server's various interfaces and features, we demonstrate two different applications: (i) we predict the structure of an antibody-antigen complex by using NMR data for the antigen and knowledge of the hypervariable loops for the antibody, and (ii) we perform coarse-grained modeling of PRC1 with a nucleosome particle guided by mutagenesis and functional data. The described protocols require some basic familiarity with molecular modeling and the Linux command shell. This new version of our widely used HADDOCK web server allows structural biologists and non-experts to explore intricate macromolecular assemblies encompassing various molecule types.

2.
Mol Phylogenet Evol ; 198: 108117, 2024 Jun 07.
Artigo em Inglês | MEDLINE | ID: mdl-38852908

RESUMO

The Least Nighthawk Chordeiles pusillus is widespread wherever there are savannas in the South American tropics, often in isolated patches, such as white-sands savannas in the Amazon rainforest realm. Here, we investigate genetic relationships between populations of the Least Nighthawk to understand historical processes leading to its diversification and to determine dispersal routes between northern and southern savannas by way of three hypothesized dispersal corridors by comparing samples from white-sand savannas to samples from other savannas outside of the Amazon rainforest region. We use 32 mtDNA samples from the range of C. pusillus to infer a dated phylogeny. In a subset of 17 samples, we use shotgun sequences to infer a distance-based phylogeny and to estimate individual admixture proportions. We calculate gene flow and shared alleles between white-sand and non-Amazonian populations using the ABBA-BABA test (D statistics), and Principal Component Analysis (PCA) to examine genetic structure within and between lineages. Finally, we use species distribution modelling (SDM) of conditions during the Last Glacial Maximum (LGM), currently, and in the future (2050-2080) to predict potential species occurrence under a climate change scenario. Two main clades (estimated to have diverged around 1.07 million years ago) were recovered with mtDNA sequences and Single Nucleotide Polymorphism (SNPs) and were supported by NGSadmix and PCA: one in the Amazon basin white-sand savannas, the other in the non-Amazonian savannas. Possible allele sharing between these clades was indicated by the D-statistics between northern non-Amazonian populations and the white-sand savanna population, but this was not corroborated by the admixture analyses. Dispersal among northern non-Amazonian populations may have occurred in a dry corridor between the Guianan and the Brazilian Shield, which has since moved eastward. Our data suggest that the lineages separated well before the Last Glacial Maximum, consequently dispersal could have happened at any earlier time during similar climatic conditions. Subsequently, non-Amazonian lineages became more divergent among themselves, possibly connecting and dispersing across the mouth of the Amazon River across Marajó island during favourable climatic conditions in the Pleistocene.

3.
bioRxiv ; 2024 Jun 03.
Artigo em Inglês | MEDLINE | ID: mdl-38895346

RESUMO

Knowledge of the structures formed by proteins and small ligands is of fundamental importance for understanding molecular principles of chemotherapy and for designing new and more effective drugs. Due to the still high costs and to the several limitations of experimental techniques, it is most often desirable to predict these ligand-protein complexes in silico , particularly when screening for new putative drugs from databases of millions of compounds. While virtual screening based on molecular docking is widely used for this purpose, it generally fails in mimicking binding events associated with large conformational changes in the protein, particularly when the latter involve multiple domains. In this work, we describe a new methodology aimed at generating bound-like conformations of very flexible and allosteric proteins bearing multiple binding sites. Validation was performed on the enzyme adenylate kinase (ADK), a paradigmatic example of proteins that undergo very large conformational changes upon ligand binding. By only exploiting the unbound structure and the putative binding sites of the protein, we generated a significant fraction of bound-like structures, which employed in ensemble-docking calculations allowed to find native-like poses of substrates, inhibitors, and catalytically incompetent binders. Our protocol provides a general framework for the generation of bound-like conformations of flexible proteins that are suitable to host different ligands, demonstrating high sensitivity to the fine chemical details that regulate protein's activity. We foresee applications in virtual screening for difficult targets, prediction of the impact of amino acid mutations on structure and dynamics, and protein engineering.

4.
Cells ; 13(11)2024 May 30.
Artigo em Inglês | MEDLINE | ID: mdl-38891083

RESUMO

The differential effects of cellular and ultrastructural characteristics on the optical properties of adaxial and abaxial leaf surfaces in the genus Tradescantia highlight the intricate relationships between cellular arrangement and pigment distribution in the plant cells. We examined hyperspectral and chlorophyll a fluorescence (ChlF) kinetics using spectroradiometers and optical and electron microscopy techniques. The leaves were analysed for their spectral properties and cellular makeup. The biochemical compounds were measured and correlated with the biophysical and ultrastructural features. The main findings showed that the top and bottom leaf surfaces had different amounts and patterns of pigments, especially anthocyanins, flavonoids, total phenolics, chlorophyll-carotenoids, and cell and organelle structures, as revealed by the hyperspectral vegetation index (HVI). These differences were further elucidated by the correlation coefficients, which influence the optical signatures of the leaves. Additionally, ChlF kinetics varied between leaf surfaces, correlating with VIS-NIR-SWIR bands through distinct cellular structures and pigment concentrations in the hypodermis cells. We confirmed that the unique optical properties of each leaf surface arise not only from pigmentation but also from complex cellular arrangements and structural adaptations. Some of the factors that affect how leaves reflect light are the arrangement of chloroplasts, thylakoid membranes, vacuoles, and the relative size of the cells themselves. These findings improve our knowledge of the biophysical and biochemical reasons for leaf optical diversity, and indicate possible implications for photosynthetic efficiency and stress adaptation under different environmental conditions in the mesophyll cells of Tradescantia plants.


Assuntos
Folhas de Planta , Tradescantia , Tradescantia/metabolismo , Folhas de Planta/metabolismo , Folhas de Planta/ultraestrutura , Fluorescência , Clorofila/metabolismo , Clorofila A/metabolismo
5.
Cureus ; 16(4): e58948, 2024 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-38800225

RESUMO

Background Despite the increasing use of wearable devices worldwide, concise data on these instruments in patients with systemic autoimmune rheumatic diseases, including idiopathic inflammatory myopathies (IIM) and primary systemic vasculitis (PSV), are lacking. Objectives The aim of this study is to investigate the knowledge and use of wearable devices and to assess their impact on the general quality of life of patients with IIM and PSV. Moreover, we compared these characteristics between patients with IIM and PSV users and non-users of wearable devices. Methods This single-center, cross-sectional study was conducted between January 2023 and June 2023. We included adult patients with IIM and PSV and a control group (CTR) and evaluated their use of cell phones and wearables, level of physical activity, and quality of life. Results A total of 132 patients with IIM, 82 with PSV, and 178 in the CTR were evaluated. Overall, 169 patients and 144 in the CTR were aware of wearable devices, of whom 50 (29.6%) and 47 (32.6%), respectively, had already used this technology. In addition, the IPAQ-Mets and EQ-5D scores were lower in the IIM and PSV groups than in the CTR, and the fatigue severity scale (FSS) scores were higher in the IIM and PSV groups than in the CTR. Patients who used the devices showed FSS scores of 29 (18-40) points, with higher levels of IPAQ-Mets among device users, indicating greater physical activity than among nonusers. Conclusion Based on the results, the use of wearable devices is associated with better fatigue and IPAQ scores. Possibly, the use of such devices can have an impact on better lifestyle habits among these patients.

6.
J Appl Toxicol ; 2024 May 07.
Artigo em Inglês | MEDLINE | ID: mdl-38715282

RESUMO

The prevalence of fragrances in various hygiene products contributes to their sensorial allure. However, fragrances can induce sensitization in the skin or respiratory system, and the mechanisms involved in this process are incompletely understood. This study investigated the intricate mechanisms underlying the fragrance's effects on sensitization response, focusing on the interplay between CYP450 enzymes, a class of drug-metabolizing enzymes, and the adaptive immune system. Specifically, we assessed the expression of CYP450 enzymes and cytokine profiles in culture of BEAS-2B and mature dendritic cells (mDC) alone or in co-culture stimulated with 2 mM of a common fragrance, cinnamyl alcohol (CA) for 20 h. CYP1A1, CYP1A2, CYP1B1, CYP2A6, and CYP2A13 were analyzed by RT-PCR and IL-10, IL-12p70, IL-18, IL-33, and thymic stromal lymphopoietin (TSLP) by Cytometric Bead Array (CBA). Through RT-PCR analysis, we observed that CA increased CYP1A2 and CYP1B1 expression in BEAS-2B, with a further increased in BEAS-2B-mDC co-culture. Additionally, exposure to CA increased IL-12p70 levels in mDC rather than in BEAS-2B-mDC co-culture. In regards to IL-18, level was higher in BEAS-2B than in BEAS-2B-mDC co-culture. A positive correlation between the levels of IL-10 and CYP1B1 was found in mDC-CA-exposed and between IL-12p70 and CYP1A1 was found in BEAS-2B after CA exposure. However, IL-12p70 and CYP1A2 as well as IL-18, IL-33, and CYP1A1 levels were negative, correlated mainly in co-culture control. These correlations highlight potential immunomodulatory interactions and complex regulatory relationships. Overall, exposure to CA enhances CYP450 expression, suggesting that CA can influence immune responses by degrading ligands on xenosensitive transcription factors.

7.
Am J Dent ; 37(2): 78-84, 2024 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-38704850

RESUMO

PURPOSE: To evaluate how fluoride- or chitosan-based toothpaste used during at-home bleaching affects enamel roughness, tooth color, and staining susceptibility. METHODS: Bovine enamel blocks were submitted to a 14-day cycling regime considering a factorial design (bleaching agent x toothpaste, 2 x 3), with n=10: (1) bleaching with 16% carbamide peroxide (CP) or 6% hydrogen peroxide (HP), and (2) daily exposure of a fluoride (1,450 ppm F-NaF) toothpaste (FT), chitosan-based toothpaste (CBT), or distilled water (control). Then, 24 hours after the last day of bleaching procedure the samples were exposed to a coffee solution. Color (ΔEab, ΔE00, L*, a*, b*) and roughness (Ra, µm) analyses were performed to compare the samples initially (baseline), after bleaching, and after coffee staining. The results were evaluated by linear models for repeated measures (L*, a*, b*, and Ra), 2-way ANOVA (ΔEab, ΔE00) and Tukey's test (α= 0.05). RESULTS: After the at-home bleaching procedure (toothpaste vs. time, P< 0.0001), the toothpaste groups presented a statistically lower Ra than the control (CBT 0.05). After coffee exposure, CBT presented lower ΔEab and ΔE00 values in the HP groups (toothpaste, P< 0.0001), and lower b* and a* values in the CP groups (toothpaste vs. time, P= 0.004). CLINICAL SIGNIFICANCE: Fluoride or chitosan delivered by toothpaste can reduce surface alterations of the enamel during at-home bleaching, without affecting bleaching efficacy.


Assuntos
Peróxido de Carbamida , Quitosana , Esmalte Dentário , Peróxido de Hidrogênio , Clareadores Dentários , Clareamento Dental , Descoloração de Dente , Cremes Dentais , Quitosana/farmacologia , Cremes Dentais/farmacologia , Animais , Bovinos , Clareamento Dental/métodos , Esmalte Dentário/efeitos dos fármacos , Clareadores Dentários/farmacologia , Peróxido de Hidrogênio/farmacologia , Peróxido de Carbamida/farmacologia , Propriedades de Superfície , Fluoretos/farmacologia , Cor , Ureia/análogos & derivados , Ureia/farmacologia , Café , Peróxidos/farmacologia
8.
Nanomaterials (Basel) ; 14(10)2024 May 09.
Artigo em Inglês | MEDLINE | ID: mdl-38786785

RESUMO

The valorization of the large amount of crude glycerol formed from the biodiesel industry is of primordial necessity. One possible direction with high interest to the biorefinery sector is the production of fuel additives such as solketal, through the acetalization of glycerol with acetone. This is a chemical process that conciliates high sustainability and economic interest, since solketal contributes to the fulfillment of a Circular Economy Model through its use in biodiesel blends. The key to guarantee high efficiency and high sustainability for solketal production is the use of recovery and recyclable heterogeneous catalysts. Reported works indicate that high yields are attributed to catalyst acidity, mainly the ones containing Brönsted acidic sites. On the other hand, the catalyst stability and its recycling capacity are completely dependent of the support material and the acidic sites incorporation methodology. This review intends to conciliate the information spread on this topic and indicate the most assertive strategies to achieve high solketal production in short reaction time during various reaction cycles.

9.
Nat Commun ; 15(1): 4119, 2024 May 15.
Artigo em Inglês | MEDLINE | ID: mdl-38750020

RESUMO

Sepsis results from systemic, dysregulated inflammatory responses to infection, culminating in multiple organ failure. Here, we demonstrate the utility of CD5L for treating experimental sepsis caused by cecal ligation and puncture (CLP). We show that CD5L's important features include its ability to enhance neutrophil recruitment and activation by increasing circulating levels of CXCL1, and to promote neutrophil phagocytosis. CD5L-deficient mice exhibit impaired neutrophil recruitment and compromised bacterial control, rendering them susceptible to attenuated CLP. CD5L-/- peritoneal cells from mice subjected to medium-grade CLP exhibit a heightened pro-inflammatory transcriptional profile, reflecting a loss of control of the immune response to the infection. Intravenous administration of recombinant CD5L (rCD5L) in immunocompetent C57BL/6 wild-type (WT) mice significantly ameliorates measures of disease in the setting of high-grade CLP-induced sepsis. Furthermore, rCD5L lowers endotoxin and damage-associated molecular pattern (DAMP) levels, and protects WT mice from LPS-induced endotoxic shock. These findings warrant the investigation of rCD5L as a possible treatment for sepsis in humans.


Assuntos
Camundongos Endogâmicos C57BL , Camundongos Knockout , Neutrófilos , Sepse , Animais , Sepse/imunologia , Sepse/tratamento farmacológico , Camundongos , Neutrófilos/imunologia , Neutrófilos/metabolismo , Fagocitose , Quimiocina CXCL1/metabolismo , Quimiocina CXCL1/genética , Modelos Animais de Doenças , Masculino , Infiltração de Neutrófilos/efeitos dos fármacos , Ceco/cirurgia , Proteínas Recombinantes/uso terapêutico , Proteínas Recombinantes/administração & dosagem , Humanos , Proteínas Citotóxicas Formadoras de Poros/metabolismo , Ligadura , Lipopolissacarídeos , Choque Séptico/imunologia
10.
Microbiome ; 12(1): 91, 2024 May 17.
Artigo em Inglês | MEDLINE | ID: mdl-38760842

RESUMO

BACKGROUND: Dark pigmented snow and glacier ice algae on glaciers and ice sheets contribute to accelerating melt. The biological controls on these algae, particularly the role of viruses, remain poorly understood. Giant viruses, classified under the nucleocytoplasmic large DNA viruses (NCLDV) supergroup (phylum Nucleocytoviricota), are diverse and globally distributed. NCLDVs are known to infect eukaryotic cells in marine and freshwater environments, providing a biological control on the algal population in these ecosystems. However, there is very limited information on the diversity and ecosystem function of NCLDVs in terrestrial icy habitats. RESULTS: In this study, we investigate for the first time giant viruses and their host connections on ice and snow habitats, such as cryoconite, dark ice, ice core, red and green snow, and genomic assemblies of five cultivated Chlorophyta snow algae. Giant virus marker genes were present in almost all samples; the highest abundances were recovered from red snow and the snow algae genomic assemblies, followed by green snow and dark ice. The variety of active algae and protists in these GrIS habitats containing NCLDV marker genes suggests that infection can occur on a range of eukaryotic hosts. Metagenomic data from red and green snow contained evidence of giant virus metagenome-assembled genomes from the orders Imitervirales, Asfuvirales, and Algavirales. CONCLUSION: Our study highlights NCLDV family signatures in snow and ice samples from the Greenland ice sheet. Giant virus metagenome-assembled genomes (GVMAGs) were found in red snow samples, and related NCLDV marker genes were identified for the first time in snow algal culture genomic assemblies; implying a relationship between the NCLDVs and snow algae. Metatranscriptomic viral genes also aligned with metagenomic sequences, suggesting that NCLDVs are an active component of the microbial community and are potential "top-down" controls of the eukaryotic algal and protistan members. This study reveals the unprecedented presence of a diverse community of NCLDVs in a variety of glacial habitats dominated by algae.


Assuntos
Vírus Gigantes , Camada de Gelo , Camada de Gelo/virologia , Groenlândia , Vírus Gigantes/genética , Vírus Gigantes/classificação , Vírus Gigantes/isolamento & purificação , Filogenia , Ecossistema , Genoma Viral , Metagenômica , Clorófitas/virologia , Clorófitas/genética , Metagenoma , Neve
11.
ACS Nano ; 18(23): 15067-15083, 2024 Jun 11.
Artigo em Inglês | MEDLINE | ID: mdl-38804165

RESUMO

Processes of water condensation and desublimation on solid surfaces are ubiquitous in nature and essential for various industrial applications, which are crucial for their performance. Despite their significance, these processes are not well understood due to the lack of methods that can provide insight at the nanolevel into the very first stages of phase transitions. Taking advantage of synchrotron grazing-incidence wide-angle X-ray scattering (GIWAXS) and environmental scanning electron microscopy (ESEM), two pathways of the frosting process from supersaturated vapors were studied in real time for substrates with different wettabilities ranging from highly hydrophilic to superhydrophobic. Within GIWAXS, a fully quantitative structural and orientational characterization of the undergoing phase transition reveals the information on degree of crystallinity of the new phase and determines the ordering at the surfaces and inside the films at the initial stages of water/ice nucleation from vapor onto the substrates. The diversity of frosting scenarios, including direct desublimation from the vapor and two-stage condensation-freezing processes, was observed by both GIWAXS and ESEM for different combinations of substrate wettability and vapor supersaturations. The classical nucleation theory straightforwardly predicts the pathway of the phase transition for hydrophobic and superhydrophobic substrates. The case of hydrophilic substrates is more intricate because the barriers in Gibbs free energy for nucleating both liquid and solid embryos are close to each other and comparable to thermal energy kBT. At that end, classical nucleation theory allows concluding a relation between contact angles for ice and water embryos on the basis of the observed frosting pathway.

12.
bioRxiv ; 2024 May 12.
Artigo em Inglês | MEDLINE | ID: mdl-38766093

RESUMO

Analysis of factors that lead to the functionality of transcriptional activation domains remains a crucial and yet challenging task owing to the significant diversity in their sequences and their intrinsically disordered nature. Almost all existing methods that have aimed to predict activation domains have involved traditional machine learning approaches, such as logistic regression, that are unable to capture complex patterns in data or plain convolutional neural networks and have been limited in exploration of structural features. However, there is a tremendous potential in the inspection of the structural properties of activation domains, and an opportunity to investigate complex relationships between features of residues in the sequence. To address these, we have utilized the power of graph neural networks which can represent structural data in the form of nodes and edges, allowing nodes to exchange information among themselves. We have experimented with two kinds of graph formulations, one involving residues as nodes and the other assigning atoms to be the nodes. A logistic regression model was also developed to analyze feature importance. For all the models, several feature combinations were experimented with. The residue-level GNN model with amino acid type, residue position, acidic/basic/aromatic property and secondary structure feature combination gave the best performing model with accuracy, F1 score and AUROC of 97.9%, 71% and 97.1% respectively which outperformed other existing methods in the literature when applied on the dataset we used. Among the other structure-based features that were analyzed, the amphipathic property of helices also proved to be an important feature for classification. Logistic regression results showed that the most dominant feature that makes a sequence functional is the frequency of different types of amino acids in the sequence. Our results consistent have shown that functional sequences have more acidic and aromatic residues whereas basic residues are seen more in non-functional sequences.

13.
Med Phys ; 51(6): 4447-4457, 2024 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-38709978

RESUMO

BACKGROUND: The use of Computed Tomography (CT) imaging data to create 3D printable patient-specific devices for radiation oncology purposes is already well established in the literature and has shown to have superior conformity than conventional methods. Using non-ionizing radiation imaging techniques such as photogrammetry or laser scanners in-lieu of a CT scanner presents many desirable benefits including reduced imaging dose and fabrication of the device can be completed prior to simulation. With recent advancements in smartphone-based technology, photographic and LiDAR-based technologies are more readily available than ever before and to a high level of quality. As a result, these non-ionizing radiation imaging methods are now able to generate patient-specific devices that can be acceptable for clinical use. PURPOSE: In this work, we aim to determine if smartphones can be used by radiation oncologists or other radiation oncology staff to generate bolus or brachytherapy surface moulds instead of conventional CT with equivalent or comparable accuracy. METHODS: This work involved two separate studies: a phantom and participant study. For the phantom study, a RANDO anthropomorphic phantom (limited to the nose region) was used to generate 3D models based on three different imaging techniques: conventional CT, photogrammetry & LiDAR which were both acquired on a smartphone. Virtual boli were designed in Blender and 3D printed from PLA plastic material. The conformity of each printed boli was assessed by measuring the air gap volume and approximate thickness between the phantom & bolus acquired together on a CT. For the participant study, photographs, and a LiDAR scan of four volunteers were captured using an iPhone 13 Pro™ to assess their feasibility for generating human models. Each virtual 3D model was visually assessed to identify any issues in their reconstruction. The LiDAR models were registered to the photogrammetry models where a distance to agreement analysis was performed to assess their level of similarity. Additionally, a 3D virtual bolus was designed and printed using ABS material from all models to assess their conformity onto the participants skin surface using a verbal feedback method. RESULTS: The photogrammetry derived bolus showed comparable conformity to the CT derived bolus while the LiDAR derived bolus showed poorer conformity as shown by their respective air gap volume and thickness measurements. The reconstruction quality of both the photogrammetry and LiDAR models of the volunteers was inadequate in regions of facial hair and occlusion, which may lead to clinically unacceptable patient-specific device that are created from these areas. All participants found the photogrammetry 3D printed bolus to conform to their nose region with minimal room to move while three of the four participants found the LiDAR was acceptable and could be positioned comfortably over their entire nose. CONCLUSIONS: Smartphone-based photogrammetry and LiDAR software show great potential for future use in generating 3D reference models for radiation oncology purposes. Further investigations into whether they can be used to fabricate clinically acceptable patient-specific devices on a larger and more diverse cohort of participants and anatomical locations is required for a thorough validation of their clinical usefulness.


Assuntos
Radioterapia (Especialidade) , Smartphone , Radioterapia (Especialidade)/instrumentação , Humanos , Imagens de Fantasmas , Impressão Tridimensional , Braquiterapia/instrumentação , Tomografia Computadorizada por Raios X/instrumentação
14.
Cell Commun Signal ; 22(1): 286, 2024 May 24.
Artigo em Inglês | MEDLINE | ID: mdl-38790044

RESUMO

BACKGROUND: T-cell membrane scaffold proteins are pivotal in T cell function, acting as versatile signaling hubs. While CD6 forms a large intracellular signalosome, it is distinguished from typical scaffolds like LAT or PAG by possessing a substantial ectodomain that binds CD166, a well-characterized ligand expressed on most antigen-presenting cells (APC), through the third domain (d3) of the extracellular region. Although the intact form of CD6 is the most abundant in T cells, an isoform lacking d3 (CD6∆d3) is transiently expressed on activated T cells. Still, the precise character of the signaling transduced by CD6, whether costimulatory or inhibitory, and the influence of its ectodomain on these activities are unclear. METHODS: We expressed CD6 variants with extracellular deletions or cytosolic mutations in Jurkat cells containing eGFP reporters for NF-κB and NF-AT transcription factor activation. Cell activation was assessed by eGFP flow cytometry following Jurkat cell engagement with superantigen-presenting Raji cells. Using imaging flow cytometry, we evaluated the impact of the CD6-CD166 pair on cell adhesiveness during the antigen-dependent and -independent priming of T cells. We also examined the role of extracellular or cytosolic sequences on CD6 translocation to the immunological synapse, using immunofluorescence-based imaging. RESULTS: Our investigation dissecting the functions of the extracellular and cytosolic regions of CD6 revealed that CD6 was trafficked to the immunological synapse and exerted tonic inhibition wholly dependent on its cytosolic tail. Surprisingly, however, translocation to the synapse occurred independently of the extracellular d3 and of engagement to CD166. On the other hand, CD6 binding to CD166 significantly increased T cell:APC adhesion. However, this activity was most evident in the absence of APC priming with superantigen, and thus, in the absence of TCR engagement. CONCLUSIONS: Our study identifies CD6 as a novel 'on/off' scaffold-receptor capable of modulating responsiveness in two ways. Firstly, and independently of ligand binding, it establishes signaling thresholds through tonic inhibition, functioning as a membrane-bound scaffold. Secondly, CD6 has the capacity for alternative splicing-dependent variable ligand engagement, modulating its checkpoint-like activity.


Assuntos
Antígenos CD , Antígenos de Diferenciação de Linfócitos T , Transdução de Sinais , Linfócitos T , Humanos , Células Jurkat , Antígenos CD/metabolismo , Antígenos CD/genética , Linfócitos T/metabolismo , Linfócitos T/imunologia , Antígenos de Diferenciação de Linfócitos T/metabolismo , Antígenos de Diferenciação de Linfócitos T/genética , Ligantes , Ativação Linfocitária , Ligação Proteica , Adesão Celular
15.
JACS Au ; 4(3): 1039-1047, 2024 Mar 25.
Artigo em Inglês | MEDLINE | ID: mdl-38559735

RESUMO

Imaging is increasingly used to detect and monitor bacterial infection. Both anatomic (X-rays, computed tomography, ultrasound, and MRI) and nuclear medicine ([111In]-WBC SPECT, [18F]FDG PET) techniques are used in clinical practice but lack specificity for the causative microorganisms themselves. To meet this challenge, many groups have developed imaging methods that target pathogen-specific metabolism, including PET tracers integrated into the bacterial cell wall. We have previously reported the d-amino acid derived PET radiotracers d-methyl-[11C]-methionine, d-[3-11C]-alanine, and d-[3-11C]-alanine-d-alanine, which showed robust bacterial accumulation in vitro and in vivo. Given the clinical importance of radionuclide half-life, in the current study, we developed [18F]3,3,3-trifluoro-d-alanine (d-[18F]-CF3-ala), a fluorine-18 labeled tracer. We tested the hypothesis that d-[18F]-CF3-ala would be incorporated into bacterial peptidoglycan given its structural similarity to d-alanine itself. NMR analysis showed that the fluorine-19 parent amino acid d-[19F]-CF3-ala was stable in human and mouse serum. d-[19F]-CF3-ala was also a poor substrate for d-amino acid oxidase, the enzyme largely responsible for mammalian d-amino acid metabolism and a likely contributor to background signals using d-amino acid derived PET tracers. In addition, d-[19F]-CF3-ala showed robust incorporation into Escherichia coli peptidoglycan, as detected by HPLC/mass spectrometry. Based on these promising results, we developed a radiosynthesis of d-[18F]-CF3-ala via displacement of a bromo-precursor with [18F]fluoride followed by chiral stationary phase HPLC. Unexpectedly, the accumulation of d-[18F]-CF3-ala by bacteria in vitro was highest for Gram-negative pathogens in particular E. coli. In a murine model of acute bacterial infection, d-[18F]-CF3-ala could distinguish live from heat-killed E. coli, with low background signals. These results indicate the viability of [18F]-modified d-amino acids for infection imaging and indicate that improved specificity for bacterial metabolism can improve tracer performance.

16.
An Acad Bras Cienc ; 96(3): e20230446, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-38655920

RESUMO

Pulmonary arterial hypertension (PAH) is characterized by right ventricular failure and diminished cardiac output, potentially leading to renal and bone impairments. In contrast, resistance exercise training (RT) offers cardiovascular and bone health benefits. This study aimed to assess the impacts of stable PAH induced by monocrotaline (MCT) and RT on renal morphometry, as well as bone morphometry and biomechanical properties in male Wistar rats. Four experimental groups, untrained control (UC, n=7), trained control (TC, n=7), untrained hypertensive (UH, n=7), trained hypertensive (TH, n=7), were defined. After the first MCT or saline injection (20 mg/kg), trained rats were submitted to a RT program (i.e., Ladder climbing), 5 times/week. Seven days later the rats received the second MCT or saline dose. After euthanasia, renal and femoral histomorphometry and femoral biomechanical properties were assessed. PAH reduced renal glomerular area and volume, which was prevented by the RT. While PAH did not harm the femoral morphometry, structural and mechanical properties, RT improved the femoral parameters (e.g., length, percentage of trabeculae and bone marrow, ultimte and yield loads). Experimental stable PAH promotes renal but not bone damages, whereas RT prevents renal deteriorations and improves the femoral morphological and biomechanical properties.


Assuntos
Modelos Animais de Doenças , Rim , Monocrotalina , Condicionamento Físico Animal , Ratos Wistar , Treinamento Resistido , Animais , Masculino , Condicionamento Físico Animal/fisiologia , Ratos , Rim/fisiopatologia , Rim/patologia , Treinamento Resistido/métodos , Hipertensão Arterial Pulmonar/fisiopatologia , Fêmur/patologia , Fêmur/fisiopatologia , Hipertensão Pulmonar/fisiopatologia , Hipertensão Pulmonar/induzido quimicamente
17.
Int J Mol Sci ; 25(8)2024 Apr 18.
Artigo em Inglês | MEDLINE | ID: mdl-38674057

RESUMO

A method has been proposed for creating an operationally durable copper coating with antimicrobial properties for the buttons of electrical switches based on the gas dynamic spray deposition of copper on acrylonitrile butadiene styrene (ABS) plastic. It is shown that during the coating process, a polymer film is formed on top of the copper layer. Comparative in situ studies of microbial contamination have shown that the copper-coated buttons have a significant antimicrobial effect compared to standard buttons. Analysis of swabs over a 22-week study in a hospital environment showed that the frequency of contamination for a copper-coated button with various microorganisms was 2.7 times lower than that of a control button. The presented results allow us to consider the developed copper coating for plastic switches an effective alternative method in the fight against healthcare-associated infections.


Assuntos
Anti-Infecciosos , Cobre , Hospitais , Cobre/química , Anti-Infecciosos/química , Anti-Infecciosos/farmacologia , Plásticos/química , Infecção Hospitalar/prevenção & controle , Humanos
18.
Mar Environ Res ; 198: 106517, 2024 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-38657369

RESUMO

Estuarine mangroves are often considered nurseries for the Atlantic Goliath grouper juveniles. Yet, the contributions of different estuarine primary producers and habitats as sources of organic matter during early ontogenetic development remain unclear. Given the species' critically endangered status and protection in Brazil, obtaining biological samples from recently settled recruits in estuaries is challenging. In this study, we leveraged a local partnership with fishers and used stable isotope (C and N) profiles from the eye lenses of stranded individuals or incidentally caught by fishery to reconstruct the trophic and habitat changes of small juveniles. The eye lens grows by the apposition of protein-rich layers. Once these layers are formed, they become inert, allowing to make inferences on the trophic ecology and habitat use along the development of the individual until its capture. We used correlations between fish size and the entire eye lens size, along with estuarine baselines, to reconstruct the fish size and trophic positions for each of the lens layers obtained. We then used dominant primary producers and basal sources from mangrove sheltered, exposed estuarine and marine habitats to construct an ontogenetic model of trophic and habitat support changes since maternal origins. Our model revealed marine support before the juveniles reached 25 mm (standard length), followed by a rapid increase in reliance on mangrove sheltered sources, coinciding with the expected size at settlement. After reaching 60 mm, individuals began to show variability. Some remained primarily supported by the mangrove sheltered area, while others shifted to rely more on the exposed estuarine area around 150 mm. Our findings indicate that while mangroves are critical for settlement, as Goliath grouper juveniles grow, they can utilize organic matter produced throughout the estuary. This underscores the need for conservation strategies that focus on seascape connectivity, as protecting just one discrete habitat may not be sufficient to preserve this endangered species and safeguard its ecosystem functions.


Assuntos
Ecossistema , Espécies em Perigo de Extinção , Cristalino , Animais , Cristalino/crescimento & desenvolvimento , Brasil , Estuários , Isótopos de Carbono/análise , Isótopos de Nitrogênio/análise , Bass/fisiologia , Bass/crescimento & desenvolvimento , Cadeia Alimentar , Monitoramento Ambiental
19.
Clin Exp Rheumatol ; 2024 Mar 07.
Artigo em Inglês | MEDLINE | ID: mdl-38451142

RESUMO

OBJECTIVES: Transcranial direct current stimulation (tDCS) combined with aerobic exercise (tDCS-AE) effectively reduces fatigue in patients with fibromyalgia. However, no study has assessed this method in systemic lupus erythematosus (SLE) patients with significant fatigue. Therefore, we evaluated the safety and efficacy of tDCS-AE for significant fatigue symptoms in adult female SLE patients. METHODS: This randomised, sham-controlled, double-blind study included 25 patients with SLE in remission or low disease activity (SLEDAI-2K £4) and with significant fatigue [≥36 points on the Fatigue Severity Scale (FSS) or ≥38 points on the Modified Fatigue Scale (MFIS)]. The patients received sham or tDCS for five consecutive days. The anode and cathode were positioned at M1 and Fp2, respectively (international 10-20 EEG system). tDCS was applied at an intensity of 2mA, and density of 0.057mA/cm2 in the tDCS-AE group. Both groups underwent combined low-intensity treadmill exercise. FSS, MFIS, pain visual analogue scale, physical activity, and sleep quality were evaluated at baseline and on days 7, 30, and 60. Adherence and safety were assessed using a standardised questionnaire. RESULTS: Improvement in fatigue levels was observed in both groups. However, a sustained reduction in fatigue levels on days 30 and 60 occurred only with tDCS-AEs (p<0.05). No significant differences were observed in pain level, sleep quality, or physical activity. No disease flares occurred and the adverse effects were mild and transient. Finally, the patient's adherence to the treatment was satisfactory. CONCLUSIONS: Despite isolated AEs, there was an improvement in fatigue, however, only tDCS-AE maintained significant and sustained improvement.

20.
Trends Biotechnol ; 2024 Mar 06.
Artigo em Inglês | MEDLINE | ID: mdl-38453559

RESUMO

Biotechnology holds the potential to revolutionize textile dyeing by utilizing biopigments, biodegradable dyes, and fermentative dyeing methods as alternatives to synthetic options. While some challenges exist, these biotechnological approaches offer innovative solutions to minimize environmental impact and foster sustainable practices, leading toward a greener, circular and efficient textile bioindustry.

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