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1.
J Cell Sci ; 137(10)2024 05 15.
Artigo em Inglês | MEDLINE | ID: mdl-38572631

RESUMO

Transition fibres and distal appendages surround the distal end of mature basal bodies and are essential for ciliogenesis, but only a few of the proteins involved have been identified and functionally characterised. Here, through genome-wide analysis, we have identified 30 transition fibre proteins (TFPs) and mapped their arrangement in the flagellated eukaryote Trypanosoma brucei. We discovered that TFPs are recruited to the mature basal body before and after basal body duplication, with differential expression of five TFPs observed at the assembling new flagellum compared to the existing fixed-length old flagellum. RNAi-mediated depletion of 17 TFPs revealed six TFPs that are necessary for ciliogenesis and a further three TFPs that are necessary for normal flagellum length. We identified nine TFPs that had a detectable orthologue in at least one basal body-forming eukaryotic organism outside of the kinetoplastid parasites. Our work has tripled the number of known transition fibre components, demonstrating that transition fibres are complex and dynamic in their composition throughout the cell cycle, which relates to their essential roles in ciliogenesis and flagellum length regulation.


Assuntos
Proteínas de Protozoários , Trypanosoma brucei brucei , Trypanosoma brucei brucei/genética , Trypanosoma brucei brucei/metabolismo , Proteínas de Protozoários/genética , Proteínas de Protozoários/metabolismo , Sequência Conservada , Corpos Basais/metabolismo , Transporte Proteico , Fatores de Tempo , Flagelos/genética , Flagelos/metabolismo , Regulação da Expressão Gênica , Cílios/genética , Cílios/metabolismo
2.
J Cell Sci ; 136(2)2023 01 15.
Artigo em Inglês | MEDLINE | ID: mdl-36661138

RESUMO

The fate of the two daughter cells is intimately connected to their positioning, which is in turn regulated by cell junction remodelling and orientation of the mitotic spindle. How multiple cues are integrated to dictate the ultimate positioning of daughters is not clear. Here, we identify novel mechanisms of regulation of daughter positioning in single MCF10A cells. The polarity protein, Scribble cooperates with E-cadherin for sequential roles in daughter positioning. First Scribble stabilises E-cadherin at the mitotic cortex as well as the retraction fibres, to mediate spindle orientation. Second, Scribble re-locates to the junction between the two daughters to allow a new E-cadherin-based-interface to form between them, influencing the width of the nascent daughter-daughter junction and subsequent cell positioning. Thus, E-cadherin and Scribble dynamically relocate to different intracellular sites during cell division to orient the mitotic spindle and control placement of the daughter cells after cell division. This article has an associated First Person interview with the first author of the paper.


Assuntos
Caderinas , Fuso Acromático , Humanos , Caderinas/genética , Caderinas/metabolismo , Divisão Celular/genética , Polaridade Celular/fisiologia , Junções Intercelulares/metabolismo , Fuso Acromático/metabolismo
3.
Cereb Cortex ; 34(7)2024 Jul 03.
Artigo em Inglês | MEDLINE | ID: mdl-39046457

RESUMO

Short association fibres (SAF) are the most abundant fibre pathways in the human white matter. Until recently, SAF could not be mapped comprehensively in vivo because diffusion weighted magnetic resonance imaging with sufficiently high spatial resolution needed to map these thin and short pathways was not possible. Recent developments in acquisition hardware and sequences allowed us to create a dedicated in vivo method for mapping the SAF based on sub-millimetre spatial resolution diffusion weighted tractography, which we validated in the human primary (V1) and secondary (V2) visual cortex against the expected SAF retinotopic order. Here, we extended our original study to assess the feasibility of the method to map SAF in higher cortical areas by including SAF up to V3. Our results reproduced the expected retinotopic order of SAF in the V2-V3 and V1-V3 stream, demonstrating greater robustness to the shorter V1-V2 and V2-V3 than the longer V1-V3 connections. The demonstrated ability of the method to map higher-order SAF connectivity patterns in vivo is an important step towards its application across the brain.


Assuntos
Mapeamento Encefálico , Imagem de Tensor de Difusão , Córtex Visual , Vias Visuais , Humanos , Córtex Visual/fisiologia , Córtex Visual/diagnóstico por imagem , Masculino , Feminino , Adulto , Imagem de Tensor de Difusão/métodos , Mapeamento Encefálico/métodos , Vias Visuais/fisiologia , Vias Visuais/diagnóstico por imagem , Substância Branca/diagnóstico por imagem , Substância Branca/fisiologia , Adulto Jovem , Processamento de Imagem Assistida por Computador/métodos
4.
Biochem J ; 481(18): 1221-1240, 2024 Sep 18.
Artigo em Inglês | MEDLINE | ID: mdl-39207824

RESUMO

Cellulosic microfibrils in plant cell walls are largely ensheathed and probably tethered by hydrogen-bonded hemicelluloses. Ensheathing may vary developmentally as hemicelluloses are peeled to enable cell expansion. We characterised a simple method to quantify ensheathed versus naked cellulosic surfaces based on the ability to adsorb a radiolabelled 'cellulose-complementary oligosaccharide', [3H]cellopentaitol. Filter-paper (cellulose) adsorbed 40% and >80% of aqueous 5 nM [3H]cellopentaitol within ∼1 and ∼20 h respectively. When [3H]cellopentaitol was rapidly dried onto filter-paper, ∼50% of it was desorbable by water, whereas after ∼1 day annealing in aqueous medium the adsorption became too strong to be reversible in water. 'Strongly' adsorbed [3H]cellopentaitol was, however, ∼98% desorbed by 6 M NaOH, ∼50% by 0.2 M cellobiose, and ∼30% by 8 M urea, indicating a role for hydrogen-bonding reinforced by complementarity of shape. Gradual adsorption was promoted by kosmotropes (1.4 M Na2SO4 or 30% methanol), and inhibited by chaotropes (8 M urea), supporting a role for hydrogen-bonding. [3H]Cellopentaitol adsorption was strongly competed by non-radioactive cello-oligosaccharides (Cell2-6), the IC50 (half-inhibitory concentration) being highly size-dependent: Cell2, ∼70 mM; Cell3, ∼7 mM; and Cell4-6, ∼0.05 mM. Malto-oligosaccharides (400 mM) had no effect, confirming the role of complementarity. The quantity of adsorbed [3H]cellopentaitol was proportional to mass of cellulose. Of seven cottons tested, wild-type Gossypium arboreum fibres were least capable of adsorbing [3H]cellopentaitol, indicating ensheathment of their microfibrillar surfaces, confirmed by their resistance to cellulase digestion, and potentially attributable to a high glucuronoarabinoxylan content. In conclusion, [3H]cellopentaitol adsorption is a simple, sensitive and quantitative way of titrating 'naked' cellulose surfaces.


Assuntos
Parede Celular , Celulose , Fibra de Algodão , Oligossacarídeos , Celulose/química , Celulose/metabolismo , Parede Celular/química , Parede Celular/metabolismo , Oligossacarídeos/química , Oligossacarídeos/metabolismo , Adsorção , Gossypium/química , Gossypium/metabolismo
5.
J Struct Biol ; 216(2): 108084, 2024 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-38479547

RESUMO

In humans, the growth pattern of the acellular extrinsic fibre cementum (AEFC) has been useful to estimate the age-at-death. However, the structural organization behind such a pattern remains poorly understood. In this study tooth cementum from seven individuals from a Mexican modern skeletal series were analyzed with the aim of unveiling the AEFC collagenous and mineral structure using multimodal imaging approaches. The organization of collagen fibres was first determined using: light microscopy, transmission electron microscopy (TEM), electron tomography, and plasma FIB scanning electron microscopy (PFIB-SEM) tomography. The mineral properties were then investigated using: synchrotron small-angle X-ray scattering (SAXS) for T-parameter (correlation length between mineral particles); synchrotron X-ray diffraction (XRD) for L-parameter (mineral crystalline domain size estimation), alignment parameter (crystals preferred orientation) and lattice parameters a and c; as well as synchrotron X-ray fluorescence for spatial distribution of calcium, phosphorus and zinc. Results show that Sharpey's fibres branched out fibres that cover and uncover other collagen bundles forming aligned arched structures that are joined by these same fibres but in a parallel fashion. The parallel fibres are not set as a continuum on the same plane and when they are superimposed project the AEFC incremental lines due to the collagen birefringence. The orientation of the apatite crystallites is subject to the arrangement of the collagen fibres, and the obtained parameter values along with the elemental distribution maps, revealed this mineral tissue as relatively homogeneous. Therefore, no intrinsic characteristics of the mineral phase could be associated with the alternating AEFC incremental pattern.


Assuntos
Cemento Dentário , Minerais , Difração de Raios X , Humanos , Cemento Dentário/ultraestrutura , Cemento Dentário/química , Cemento Dentário/metabolismo , Difração de Raios X/métodos , Minerais/metabolismo , Minerais/química , Colágeno/química , Colágeno/metabolismo , Microscopia Eletrônica de Transmissão/métodos , Espalhamento a Baixo Ângulo , Microscopia Eletrônica de Varredura/métodos , Tomografia com Microscopia Eletrônica/métodos , Feminino , Adulto , Masculino , Pessoa de Meia-Idade
6.
J Physiol ; 602(8): 1681-1702, 2024 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-38502562

RESUMO

In skeletal muscle, glycogen particles are distributed both within and between myofibrils, as well as just beneath the sarcolemma. Their precise localisation may influence their degradation rate. Here, we investigated how exercise at different intensities and durations (1- and 15-min maximal exercise) with known variations in glycogenolytic rate and contribution from anaerobic metabolism affects utilisation of the distinct pools. Furthermore, we investigated how decreased glycogen availability achieved through lowering carbohydrate and energy intake after glycogen-depleting exercise affect the storage of glycogen particles (size, numerical density, localisation). Twenty participants were divided into two groups performing either a 1-min (n = 10) or a 15-min (n = 10) maximal cycling exercise test. In a randomised, counterbalanced, cross-over design, the exercise tests were performed following short-term consumption of two distinct diets with either high or moderate carbohydrate content (10 vs. 4 g kg-1 body mass (BM) day-1) mediating a difference in total energy consumption (240 vs. 138 g kg-1 BM day-1). Muscle biopsies from m. vastus lateralis were obtained before and after the exercise tests. Intermyofibrillar glycogen was preferentially utilised during the 1-min test, whereas intramyofibrillar glycogen was preferentially utilised during the 15-min test. Lowering carbohydrate and energy intake after glycogen-depleting exercise reduced glycogen availability by decreasing particle size across all pools and diminishing numerical density in the intramyofibrillar and subsarcolemmal pools. In conclusion, distinct subcellular glycogen pools were differentially utilised during 1-min and 15-min maximal cycling exercise. Additionally, lowered carbohydrate and energy consumption after glycogen-depleting exercise altered glycogen storage by reducing particle size and numerical density, depending on subcellular localisation. KEY POINTS: In human skeletal muscle, glycogen particles are localised in distinct subcellular compartments, referred to as intermyofibrillar, intramyofibrillar and subsarcolemmal pools. The intermyofibrillar and subsarcolemmal pools are close to mitochondria, while the intramyofibrillar pool is at a distance from mitochondria. We show that 1 min of maximal exercise is associated with a preferential utilisation of intermyofibrillar glycogen, and, on the other hand, that 15 min of maximal exercise is associated with a preferential utilisation of intramyofibrillar glycogen. Furthermore, we demonstrate that reduced glycogen availability achieved through lowering carbohydrate and energy intake after glycogen-depleting exercise is characterised by a decreased glycogen particle size across all compartments, with the numerical density only diminished in the intramyofibrillar and subsarcolemmal compartments. These results suggest that exercise intensity influences the subcellular pools of glycogen differently and that the dietary content of carbohydrates and energy is linked to the size and subcellular distribution of glycogen particles.


Assuntos
Glicogênio , Músculo Esquelético , Humanos , Glicogênio/metabolismo , Músculo Esquelético/fisiologia , Miofibrilas/metabolismo , Exercício Físico/fisiologia , Músculo Quadríceps/metabolismo , Carboidratos da Dieta/metabolismo
7.
Eur J Neurosci ; 60(5): 5019-5039, 2024 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-39099396

RESUMO

Modulation of input from primary afferent fibres has long been examined at the level of the first relays of these fibres. However, recent studies reveal that input to the spinal cord may also be modulated at the level of the very entry of afferent fibres to the spinal grey matter before action potentials in intraspinal collaterals of afferent fibres reach their target neurons. Such modulation greatly depends on the actions of GABA via extrasynaptic membrane receptors. In the reported study we hypothesized that the increase in excitability of afferent fibres following epidural polarization close to the site where collaterals of afferent fibres leave the dorsal columns is due to the release of GABA from two sources: not only GABAergic interneurons but also glial cells. We present evidence, primo, that GABA released from both these sources contributes to a long-lasting increase in the excitability and a shortening of the refractory period of epidurally stimulated afferent fibres and, secondo, that effects of epidural polarization on the release of GABA are more critical for these changes than direct effects of DC on the stimulated fibres. The experiments were carried out in deeply anaesthetized rats in which changes in compound action potentials evoked in hindlimb peripheral nerves by dorsal column stimulation were used as a measure of the excitability of afferent fibres. The study throws new light on the modulation of input to spinal networks but also on mechanisms underlying the restoration of spinal functions.


Assuntos
Interneurônios , Neuroglia , Medula Espinal , Ácido gama-Aminobutírico , Animais , Interneurônios/metabolismo , Interneurônios/fisiologia , Medula Espinal/metabolismo , Medula Espinal/fisiologia , Ratos , Ácido gama-Aminobutírico/metabolismo , Neuroglia/metabolismo , Neuroglia/fisiologia , Masculino , Potenciais de Ação/fisiologia , Espaço Epidural/fisiologia , Estimulação Elétrica , Ratos Wistar , Ratos Sprague-Dawley , Vias Aferentes/fisiologia , Vias Aferentes/metabolismo
8.
Small ; 20(33): e2400580, 2024 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-38529758

RESUMO

During synthetic textile washing, rubbing between fibres or against the washing machine, exacerbated by the elevated temperature, initiates the release of millions of microplastic fibres into the environment. A general tribological strategy is reported that practically eliminates the release of microplastic fibres from laundered apparel. The two-layer fabric finishes combine low-friction, liquidlike polymer brushes with "molecular primers", that is, molecules that durably bond the low-friction layers to the surface of the polyester or nylon fabrics. It is shown that when the coefficient of friction is below a threshold of 0.25, microplastic fibre release is substantially reduced, by up to 96%. The fabric finishes can be water-wicking or water-repellent, and their comfort properties are retained after coating, indicating a tunable and practical strategy toward a sustainable textile industry and plastic-free oceans and marine foodstuffs.

9.
J Anat ; 2024 Sep 10.
Artigo em Inglês | MEDLINE | ID: mdl-39253979

RESUMO

Contractions of the uterus play an important role in menstruation and fertility, and contractile dysfunction can lead to chronic diseases such as endometriosis. However, the structure and function of the uterus are difficult to interrogate in humans, and thus animal studies are often employed to understand its function. In rats, anatomical studies of the uterus have typically been based on histological assessment, have been limited to small segments of the uterine structure, and have been time-consuming to reconstruct at the organ scale. This study used micro-computed tomography imaging to visualise the muscle structures in the entire non-pregnant rat uterus and assess its use for 3D virtual histology. An assessment of the rodent uterus is presented to (i) quantify muscle thickness variations along the horns, (ii) identify predominant fibre orientations of the muscles and (iii) demonstrate how the anatomy of the uterus can be mapped to 3D volumetric meshes via virtual histology. Micro-computed tomography measurements were validated against measurements from histological sections. The average thickness of the myometrium was found to be 0.33 ± 0.11 mm and 0.31 ± 0.09 mm in the left and right horns, respectively. The micro-computed tomography and histology thickness calculations were found to correlate strongly at different locations in the uterus: at the cervix, r = 0.87, and along the horn from the cervical end to the ovarian end, respectively, r = 0.77, r = 0.89 and r = 0.54, with p < 0.001 in every location. This study shows that micro-computed tomography can be used to quantify the musculature in the whole non-pregnant uterus and can be used for 3D virtual histology.

10.
Acta Neuropathol ; 147(1): 60, 2024 03 25.
Artigo em Inglês | MEDLINE | ID: mdl-38526612

RESUMO

Preclinical studies indicate that diverse muscarinic receptor antagonists, acting via the M1 sub-type, promote neuritogenesis from sensory neurons in vitro and prevent and/or reverse both structural and functional indices of neuropathy in rodent models of diabetes. We sought to translate this as a potential therapeutic approach against structural and functional indices of diabetic neuropathy using oxybutynin, a muscarinic antagonist approved for clinical use against overactive bladder. Studies were performed using sensory neurons maintained in vitro, rodent models of type 1 or type 2 diabetes and human subjects with type 2 diabetes and confirmed neuropathy. Oxybutynin promoted significant neurite outgrowth in sensory neuron cultures derived from adult normal rats and STZ-diabetic mice, with maximal efficacy in the 1-100 nmol/l range. This was accompanied by a significantly enhanced mitochondrial energetic profile as reflected by increased basal and maximal respiration and spare respiratory capacity. Systemic (3-10 mg/kg/day s.c.) and topical (3% gel daily) oxybutynin reversed paw heat hypoalgesia in the STZ and db/db mouse models of diabetes and reversed paw tactile allodynia in STZ-diabetic rats. Loss of nerve profiles in the skin and cornea of db/db mice was also prevented by daily topical delivery of 3% oxybutynin for 8 weeks. A randomized, double-blind, placebo-controlled interventional trial was performed in subjects with type 2 diabetes and established peripheral neuropathy. Subjects received daily topical treatment with 3% oxybutynin gel or placebo for 6 months. The a priori designated primary endpoint, significant change in intra-epidermal nerve fibre density (IENFD) in skin biopsies taken before and after 20 weeks of treatments, was met by oxybutynin but not placebo. Secondary endpoints showing significant improvement with oxybutynin treatment included scores on clinical neuropathy, pain and quality of life scales. This proof-of-concept study indicates that muscarinic antagonists suitable for long-term use may offer a novel therapeutic opportunity for treatment of diabetic neuropathy. Trial registry number: NCT03050827.


Assuntos
Neuropatias Diabéticas , Antagonistas Muscarínicos , Animais , Humanos , Camundongos , Ratos , Diabetes Mellitus Experimental/complicações , Diabetes Mellitus Experimental/tratamento farmacológico , Diabetes Mellitus Experimental/patologia , Diabetes Mellitus Tipo 2/complicações , Diabetes Mellitus Tipo 2/tratamento farmacológico , Neuropatias Diabéticas/tratamento farmacológico , Neuropatias Diabéticas/complicações , Neuropatias Diabéticas/patologia , Ácidos Mandélicos , Antagonistas Muscarínicos/farmacologia , Antagonistas Muscarínicos/uso terapêutico , Qualidade de Vida , Receptores Muscarínicos , Diabetes Mellitus Tipo 1
11.
Exp Dermatol ; 33(3): e15052, 2024 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-38483134

RESUMO

Skin forms the outer barrier of the body. Upon injury, successful wound healing in normal skin restores tissue damage and counteracts the loss of extracellular matrix (ECM) proteins and cells. Collagens and elastin are the most abundant structural proteins of the ECM. In homeostasis, collagen type I is the prevalent form, but it is replaced by type III collagen upon wounding, and only later remodelled. In turn, unsuccessful healing results in scars, which tend to be inflexible and inelastic as compared to normal elastic dermis. Scar inelasticity may be due to the absence of mature elastin fibre formation and cross-linking. In this review, the available information on the process of formation of new collagen and elastic fibres during wound healing is analysed. The distinct roles of elastin and collagen proteins during healing are revisited and future research directions proposed which may help improve clinical management of open wounds and scars.


Assuntos
Cicatriz , Matriz Extracelular , Humanos , Cicatriz/metabolismo , Matriz Extracelular/metabolismo , Colágeno/metabolismo , Pele/metabolismo , Elastina/metabolismo , Proteínas da Matriz Extracelular/metabolismo , Cicatrização
12.
J Microsc ; 294(2): 239-250, 2024 May.
Artigo em Inglês | MEDLINE | ID: mdl-38597232

RESUMO

Engineered cementitious composites (ECC) are a class of high-performing fibre-reinforced cementitious materials recognised for their increased ductility and durability compared to conventional cement-based materials, owing to their autogenously controlled tight crack widths, even when subjected to high strains. To reduce ECC's environmental impact, this research examines the use of a low-clinker binder - limestone-calcined clay cement (LC3) - as an alternative to portland cement (PC), along with fly ash to further reduce the clinker proportion and the embodied CO2 of the formulations. In conventional concrete, LC3 hydrates to a denser microstructure resulting from the synergistic reaction between limestone and calcined clay. At the lower water contents typical of ECC and with the presence of fly ash, the influence of the binder composition on the microstructure is difficult to anticipate. To examine the influence of these compositional variables on microstructure, permeability and durability, the sulphate resistance of LC3-based ECC is explored. Specifically, the ECC-LC3 blends are designed with high clinker replacement rate of 75% by mass of binder and contain either conventional fly ash or reclaimed fly ash at 50% by mass of binder. Expansion of ECC-LC3 samples subjected to standard sodium sulphate test conditions was measured up to 12 months and the depth of penetration of sulphates into the ECC-LC3 of varying compositions was quantified using micro-X-Ray Fluorescence (microXRF) imaging and modelling. The expansion results show that the ECC-LC3 formulations performed better than the PC samples and can provide adequate resistance to external sulphate attack, even when reclaimed fly ashes are used in place of the conventional ash. In addition, the shallow penetration of sulphate into these cementitious composites demonstrates the low diffusion coefficients values that were determined using the quantitative data from MicroXRF imaging.

13.
J Microsc ; 294(2): 233-238, 2024 May.
Artigo em Inglês | MEDLINE | ID: mdl-38576376

RESUMO

The performance of cementitious composites reinforced with fibres or/and bars depends on the bond strength between inclusion and cementitious matrix. The nature of formation of fibre-matrix bond is crucial for enhancing the reliability and utilisation of reinforced composites. The research provides a review on the recently published result about the changes in the microstructure of cement matrix surrounding steel fibres with different surface roughness, using a scanning electron microscope (SEM) coupled with k-means clustering algorithm for image segmentation. The debonding pattern of the fibre-matrix bond after the tensile loading cycles was discussed by observing the amount of adhered cement paste to the pulled out fibre surface with SEM. Therefore, analysis of SEM images enabled to explain the connection between the micro-scale properties of cement paste and fibre after application of cyclic loading.

14.
J Peripher Nerv Syst ; 29(3): 329-338, 2024 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-39164223

RESUMO

AIMS: To develop a standardised, automated protocol for detecting protein gene product 9.5 (PGP9.5) positive intra-epidermal nerve fibres (IENFs) in skin biopsies, transitioning from the established manual technique to an automated platform. This automated method, although currently intended for research applications, may improve the accessibility of this diagnostic test for small fibre neuropathy in clinical settings. METHODS: Skin biopsies (n = 274) from 100 participants (fibromyalgia syndrome n = 62; idiopathic small fibre neuropathy: n = 16; healthy volunteers: n = 22) were processed using an automated immunohistochemistry platform. IENF quantification was performed by blinded examiners, with reliability assessed via a two-way mixed-effects model to evaluate inter- and intra-observer variability. RESULTS: The automated staining system reproduced intra-epidermal nerve fibre density (IENFD) counts consistent with free-floating sections (mean ± standard deviation: free-floating: 5.6 ± 3.4 fibres/mm; automated: 5.9 ± 3.2 fibres/mm). A median difference of 0.3 with a lower bound 95% Confidence Interval (CI) at -0.00005 established non-inferiority against a margin of -0.4 (p = .08). Specifically, the inter-class correlation coefficient (class denotes consistency in measured observations) was 99% (95% CI: 0.9-1), indicating excellent agreement between free-floating and automated methods. The inter- and intra-class coefficient between examiners were both 99% (95% CI: 0.9-0.1) for IENFD, demonstrating high reliability using sections stained using the automated method. INTERPRETATION: Automated immunohistochemistry provides high-throughput reliable and reproducible intra-epidermal nerve fibre quantification. This method, although currently proof-of-concept, for research use only, may be more widely deployed in histopathology laboratories to increase the adoption of IENFD assessment for the diagnosis of peripheral neuropathies.


Assuntos
Imuno-Histoquímica , Fibras Nervosas , Estudo de Prova de Conceito , Pele , Neuropatia de Pequenas Fibras , Humanos , Fibras Nervosas/patologia , Feminino , Masculino , Adulto , Pessoa de Meia-Idade , Pele/inervação , Pele/patologia , Neuropatia de Pequenas Fibras/diagnóstico , Neuropatia de Pequenas Fibras/patologia , Biópsia , Epiderme/inervação , Epiderme/patologia , Idoso , Ubiquitina Tiolesterase/metabolismo , Ubiquitina Tiolesterase/análise , Reprodutibilidade dos Testes
15.
Environ Res ; 245: 118016, 2024 Mar 15.
Artigo em Inglês | MEDLINE | ID: mdl-38154563

RESUMO

Recovery of carbon fibres and resin from wind turbine blade waste (WTB) composed of carbon fibres (CF)-reinforced unsaturated polyester resin (UPR) has been environmentally challenging due to its complex structure that is not biodegradable and that is rich in highly toxic styrene (main component of UPR). Within this framework, this paper aims to liberate CF and UPR from WTB using a pyrolysis process. The treatment was performed on commercial WTB (CF/UPR) up to 600 °C using a 250 g reactor. The UPR fraction was decomposed into liquid and gaseous phases, while CF remained as a residue. The composition of gaseous phase was monitored during the entire treatment using a digital gas analyser, while gas chromatography-mass spectrometry (GC-MS) was used to characterize the collected liquid phase. CF fraction was collected and exposed to additional oxidation process after treatment at 450 °C for purification propose, then it was analysed using FTIR and SEM-EDX. Finally, the life cycle assessment (LCA) of the CF/UPR pyrolysis was studied using SimaPro software and the results were compared with landfill disposal practices. The pyrolysis results manifested that 500 °C was sufficient for UPR decomposition into styrene-rich oil and gaseous products with yields of 15.23 wt% and 6.83 wt%, respectively, accompanied by 77.93 wt% solid residue including CF. The LCA results showed that pyrolysis with oxidation process has high environmental potential in WTB recycling with significant reduction in several impact categories compared to landfill. However, the pyrolysis scenario revealed several additional environmental burdens related to ecosystems, acidification, Ozone formation, and fine particulate matter formation that must be overcome before upscaling.


Assuntos
Ecossistema , Pirólise , Fibra de Carbono , Poliésteres , Estireno , Carbono
16.
Environ Res ; 248: 118307, 2024 May 01.
Artigo em Inglês | MEDLINE | ID: mdl-38307187

RESUMO

Microplastic pollution is a global issue of great public concern. Africa is flagged to host some of the most polluted water bodies globally, but there is no enough information on the extent of microplastic contamination and the potential risks of microplastic pollution in African aquatic ecosystems. This meta-analysis has integrated data from published articles about microplastic pollution in African aquatic ecosystems. The data on the microplastic distribution and morphological characteristics in water, sediments and biota from African rivers, lakes, oceans and seas were extracted from 75 selected studies. Multivariate statistics were used to critically analyze the effects of sampling and detection methods, ecological risks, spatial distribution and similarity of microplastics in relation to the geographical distance between sampling sites. This study found that sampling methods have significant effect on abundance and morphological characteristics of microplastics and that African aquatic ecosystems are highly contaminated with microplastics compared to global data. The most prevalent colors were white, transparent and black, the most prevalent shapes were fibres and fragments, and the most available polymers were polypropylene (PP), polystyrene (PS) and polyethene terephthalate (PET). Microplastic polymers similarity decreased with an increase in geographical distance between sites. Risk levels of microplastics in African aquatic ecosystems were comparatively high, and more than 40 % of water and sediments showed highest level of ecological risk. This review provides recent information on the prevalence, distribution and risks of microplastics in African aquatic ecosystems.


Assuntos
Microplásticos , Poluentes Químicos da Água , Plásticos/análise , Ecossistema , Monitoramento Ambiental , Poluentes Químicos da Água/análise , África , Poluição da Água/análise , Água , Sedimentos Geológicos
17.
Nutr Neurosci ; : 1-14, 2024 Jan 03.
Artigo em Inglês | MEDLINE | ID: mdl-38170169

RESUMO

Over recent decades, dietary patterns have changed significantly due to the increasing availability of convenient, ultra-processed refined foods. Refined foods are commonly depleted of key bioactive compounds, which have been associated with several deleterious health conditions. As the gut microbiome can influence the brain through a bidirectional communication system known as the 'microbiota-gut-brain axis', the consumption of refined foods has the potential to affect cognitive health. In this study, multi-omics approaches were employed to assess the effect of a refined diet on the microbiota-gut-brain axis, with a particular focus on bile acid metabolism. Mice maintained on a refined low-fat diet (rLFD), consisting of high sucrose, processed carbohydrates and low fibre content, for eight weeks displayed significant gut microbial dysbiosis, as indicated by diminished alpha diversity metrics (p < 0.05) and altered beta diversity (p < 0.05) when compared to mice receiving a chow diet. Changes in gut microbiota composition paralleled modulation of the metabolome, including a significant reduction in short-chain fatty acids (acetate, propionate and n-butyrate; p < 0.001) and alterations in bile acid concentrations. Interestingly, the rLFD led to dysregulated bile acid concentrations across both the colon (p < 0.05) and the brain (p < 0.05) which coincided with altered neuroinflammatory gene expression. In particular, the concentration of TCA, TDCA and T-α-MCA was inversely correlated with the expression of NF-κB1, a key transcription factor in neuroinflammation. Overall, our results suggest a novel link between a refined low-fat diet and detrimental neuronal processes, likely in part through modulation of the microbiota-gut-brain axis and bile acid dysmetabolism.

18.
Nutr Metab Cardiovasc Dis ; 34(6): 1416-1426, 2024 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-38499450

RESUMO

BACKGROUND AND AIMS: The gut microbiome exerts important roles in health, e.g., functions in metabolism and immunology. These functions are often exerted via short-chain fatty acid (SCFA) production by gut bacteria. Studies demonstrating causal relationships between interventions targeting the microbiome and clinical outcomes are limited. This study aimed to show a causal relationship between microbiome modulation through fibre intervention and health. METHODS AND RESULTS: This randomized, double-blind, cross-over study included 65 healthy subjects, aged 45-70 years, with increased metabolic risk (i.e., body mass index [BMI] 25-30 kg/m2, low to moderate daily dietary fibre intake, <30g/day). Subjects took daily a fibre mixture of Acacia gum and carrot powder or placebo for 12 weeks, with an 8-week wash-out period. Faecal samples for measurement of SCFAs and microbiome analysis were collected every 4 weeks. Before and after each intervention period subjects underwent the mixed-meal PhenFlex challenge Test (PFT). Health effects were expressed as resilience to the stressors of the PFT and as fasting metabolic and inflammatory state. The fibre mixture exerted microbiome modulation, with an increase in ß-diversity (p < 0.001). α-diversity was lower during fibre mixture intake compared to placebo after 4, 8 and 12 weeks (p = 0.002; p = 0.012; p = 0.031). There was no effect observed on faecal SCFA concentrations, nor on any of the primary clinical outcomes (Inflammatory resilience: p = 0.605, Metabolic resilience: p = 0.485). CONCLUSION: Although the intervention exerted effects on gut microbiome composition, no effects on SCFA production, on resilience or fasting metabolic and inflammatory state were observed in this cohort. REGISTRATION NUMBER CLINICALTRIALS.GOV: NCT04829396.


Assuntos
Bactérias , Estudos Cross-Over , Fibras na Dieta , Suplementos Nutricionais , Ácidos Graxos Voláteis , Fezes , Microbioma Gastrointestinal , Voluntários Saudáveis , Humanos , Pessoa de Meia-Idade , Fibras na Dieta/administração & dosagem , Masculino , Microbioma Gastrointestinal/efeitos dos fármacos , Feminino , Método Duplo-Cego , Idoso , Ácidos Graxos Voláteis/metabolismo , Fezes/microbiologia , Fezes/química , Bactérias/classificação , Bactérias/metabolismo , Bactérias/crescimento & desenvolvimento , Fatores de Tempo , Goma Arábica , Resultado do Tratamento
19.
Public Health Nutr ; 27(1): e103, 2024 Mar 26.
Artigo em Inglês | MEDLINE | ID: mdl-38529770

RESUMO

OBJECTIVE: The recommended level of five fruits and vegetables per day is reached by a minority of French children. No-added sugars fruit puree (NASFP) can be consumed as a complement of fresh fruit to meet the recommendation for fruits and vegetables. The objective was to simulate the nutritional impact of an increase in consumption of NASFP among French children, together with a reduction in sweetened foods. DESIGN: The study was conducted on French children aged 1-17 years. The simulation consisted in introducing NASFP on four different eating occasions (breakfast, lunch, snack and dinner) to reach one serving and removing the same serving of sweetened foods. Intakes in nutrients to favour, nutrients to limit and prevalence of adequacy to nutritional requirements were compared between observed and simulated diets in the whole sample and in five different age groups. SETTING: France. PARTICIPANTS: Children from 1 to 17 years of age in the last available French representative dietary survey (INCA3). RESULTS: Simulated diets were more nutrient-dense thanks to increases in nutrients to favour from NASFP (especially fibres, iodine, Se, and vitamin A and C) associated with reductions in energy and nutrients to limit (especially free sugars) coming from sweetened foods. Prevalence of adequacy increased from 2 to 14·5 points for fibres and from 4·5 to 12 points for free sugars according to age group and eating occasion. CONCLUSION: Promoting NASFP in replacement of sweetened products is a promising strategy to improve the nutritional quality of French children's diet through a better adherence to national guidelines.


Assuntos
Frutas , Açúcares , Criança , Humanos , Lactente , Pré-Escolar , Adolescente , Dieta , Verduras , Valor Nutritivo , Ingestão de Energia
20.
Biofouling ; 40(7): 415-430, 2024 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-38984682

RESUMO

Artificial reefs represent useful tools to revitalize coastal and ocean ecosystems. Their formulation determines the biofilm formation which is the prerequisite for the colonization process by marine micro- and macroorganisms. In comparison with concrete, biobased polymers offer improved characteristics, including architecture, formulation, rugosity and recycling. This article aims to explore a new scale of artificial reef made of biocomposites reinforced with a high flax fibre (Linum utilatissimum) content (30%). Cellular adhesion and resulting biofilm formation were assessed using two marine microorganisms: Pseudoalteromonas sp. 3J6 and Cylindrotheca closterium. The influence of flax fibre leachates and plastic monomers on the growth of those marine microorganisms were also evaluated. Results indicated that the introduction of flax fibres inside the polymer matrix modified its physicochemical properties thus modulating adhesion and biofilm formation depending on the microorganism. This study gives insights for further developments of novel functionalized artificial reefs made of biocomposites.


Assuntos
Biofilmes , Linho , Pseudoalteromonas , Biofilmes/crescimento & desenvolvimento , Linho/microbiologia , Linho/química , Pseudoalteromonas/fisiologia , Aderência Bacteriana
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