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1.
Planta ; 260(1): 21, 2024 Jun 07.
Artigo em Inglês | MEDLINE | ID: mdl-38847829

RESUMO

MAIN CONCLUSION: Petal developmental characteristics in Fumarioideae were similar at early stages, and the specialized nectar holder/pollen container formed by the outer/inner petals. The micro-morphology of these two structures, however, shows diversity in seven species. Elaborate petals have been modified to form different types, including petal lobes, ridges, protuberances, and spurs, each with specialized functions. Nectar holder and pollen container presumably have a function in plant-pollinator interactions. In Fumarioideae, four elaborate petals of the disymmetric/zygomorphic flower present architecture forming the "nectar holder" and "pollen container" structure at the bottom and top separately. In the present study, the petals of seven species in Fumarioideae were investigated by scanning electron microscopy, light microscope, and transmission electron microscopes. The results show that petal development could divided into six stages: initiation, enlargement, adaxial/abaxial differentiation, elaborate specializations (sacs, spurs, and lobes formed), extension, and maturation, while the specialized "nectar holder" and "pollen container" structures mainly formed in stage 4. "Nectar holder" is developed from the shallow sac/spur differentiated at the base of the outer petal, eventually forming a multi-organized complex structure, together with staminal nectaries (1-2) with individual sizes. A semi-closed ellipsoidal "pollen container" is developed from the apical part of the 3-lobed inner petals fused by middle lobes and attain different sizes. The adaxial epidermis cells are specialized, with more distinct punctate/dense columnar protrusions or wavy cuticles presented on obviously thickening cell walls. In addition, a large and well-developed cavity appears between the inner and outer epidermis of the petals. As an exception, Hypecoum erectum middle lobes present stamen mimicry. Elaborate petal structure is crucial for comprehending the petal diversity in Fumarioideae and provides more evidence for further exploration of the reproductive study in Papaveraceae.


Assuntos
Flores , Microscopia Eletrônica de Varredura , Néctar de Plantas , Pólen , Flores/anatomia & histologia , Flores/ultraestrutura , Flores/crescimento & desenvolvimento , Pólen/ultraestrutura , Microscopia Eletrônica de Transmissão , Polinização
2.
Sci Rep ; 14(1): 13019, 2024 06 06.
Artigo em Inglês | MEDLINE | ID: mdl-38844492

RESUMO

In recent years functional multiphoton (MP) imaging of vital mouse tissues and stimulation emission depletion (STED) imaging of optically cleared tissues allowed new insights into kidney biology. Here, we present a novel workflow where MP imaging of calcium signals can be combined with super-resolved STED imaging for morphological analysis of the slit diaphragm (SD) within the same glomerulus. Mice expressing the calcium indicator GCaMP3 in podocytes served as healthy controls or were challenged with two different doses of nephrotoxic serum (NTS). NTS induced glomerular damage in a dose dependent manner measured by shortening of SD length. In acute kidney slices (AKS) intracellular calcium levels increased upon disease but showed a high variation between glomeruli. We could not find a clear correlation between intracellular calcium levels and SD length in the same glomerulus. Remarkably, analysis of the SD morphology of glomeruli selected during MP calcium imaging revealed a higher percentage of completely disrupted SD architecture than estimated by STED imaging alone. Our novel co-imaging protocol is applicable to a broad range of research questions. It can be used with different tissues and is compatible with diverse reporters and target proteins.


Assuntos
Cálcio , Glomérulos Renais , Microscopia de Fluorescência por Excitação Multifotônica , Podócitos , Animais , Podócitos/metabolismo , Cálcio/metabolismo , Camundongos , Glomérulos Renais/metabolismo , Glomérulos Renais/ultraestrutura , Microscopia de Fluorescência por Excitação Multifotônica/métodos
3.
Sci Rep ; 14(1): 12998, 2024 06 06.
Artigo em Inglês | MEDLINE | ID: mdl-38844535

RESUMO

The challenge of in-situ handling and high-resolution low-dose imaging of intact, sensitive and wet samples in their native state at nanometer scale, including live samples is met by Advanced Environmental Scanning Electron Microscopy (A-ESEM). This new generation of ESEM utilises machine learning-based optimization of thermodynamic conditions with respect to sample specifics to employ a low temperature method and an ionization secondary electron detector with an electrostatic separator. A modified electron microscope was used, equipped with temperature, humidity and gas pressure sensors for in-situ and real-time monitoring of the sample. A transparent ultra-thin film of ionic liquid is used to increase thermal and electrical conductivity of the samples and to minimize sample damage by free radicals. To validate the power of the new method, we analyze condensed mitotic metaphase chromosomes to reveal new structural features of their perichromosomal layer, and the organization of chromatin fibers, not observed before by any microscopic technique. The ability to resolve nano-structural details of chromosomes using A-ESEM is validated by measuring gold nanoparticles with achievable resolution in the lower nanometre units.


Assuntos
Microscopia Eletrônica de Varredura , Microscopia Eletrônica de Varredura/métodos , Humanos , Ouro/química , Nanopartículas Metálicas/química , Mitose , Cromossomos/ultraestrutura
4.
J Comp Neurol ; 532(6): e25644, 2024 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-38852044

RESUMO

For postmetamorphic specimens of amphioxus (Cephalochordata), serial block-face scanning electron microscopy (SBSEM) is used to describe the long-ignored Rohde-like cells (RLCs) at the extreme posterior end of the dorsal nerve cord. These cells, numbering about three dozen in all, are divisible into a group with larger diameters running near the dorsal side of the cord and a more ventral group with smaller diameters closely associated with the central canal of the neurocoel. It is possible that the smaller ventral cells might be generated at the ependymal zone of the dorsal nerve cord and later migrate to a dorsal position, although a functional reason for this remains a mystery. All the RLCs have conspicuous regions of microvilli covering as much as 40% of their surface; limited data (by others) on the more anterior bona fide Rohde cells also indicate an extensive microvillar surface. Thus, both the RLCs and the better-known Rohde cells appear to be rhabdomeric photoreceptors, although a specific function for this feature is currently unknown. Even more perplexingly, although the Rohde cells are quintessential neurons extending giant processes, each RLC comprises a perikaryon that does not bear any neurites.


Assuntos
Anfioxos , Animais , Microscopia Eletrônica de Varredura , Neurônios/ultraestrutura , Neurônios/citologia
5.
Vet Q ; 44(1): 1-11, 2024 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-38832661

RESUMO

Hemorrhagic bowel syndrome (HBS) is characterized by a dissecting intramucosal hematoma at the small bowel, causing obstruction and severe hemorrhage in dairy cattle. Recent investigation revealed the presence of early-stage lesions in cows affected by HBS. These are presumed to be the initial stage of the hematoma, as both share unique dissection of the lamina muscularis mucosae (LMM) as histological hallmark. Early-stage lesions of HBS have not been characterized in greater detail, and neither has the hypothesis of mucosal abrasion as etiology been explored. Therefore, the first objective of the present study was to characterize the morphology of early-stage lesions, by gross examination, histochemistry, immunohistochemistry and transmission electron microscopy. The second objective was to determine the effect of mucosal abrasion to the small intestine in an ex vivo model. A total of 86 early-stage lesions from 10 cows with HBS were characterized. No underlying alterations at the LMM were evident which could explain their occurrence. However, degeneration at the ultrastructural level of the LMM smooth muscle cells was present in 3 of 4 lesions, it is however unclear whether this is primary or secondary. Bacteriological examination did not reveal any association with a specific bacterium. Experimental-induced and early-stage lesions were gross and histologically evaluated and scored in three cows with HBS and seven controls. Experimentally induced lesions in both affected cows and controls, were histologically very similar to the naturally occurring early-stage lesions. Altogether, the results are suggestive for mucosal trauma to play a role in the pathogenesis of HBS.


Assuntos
Doenças dos Bovinos , Hemorragia Gastrointestinal , Mucosa Intestinal , Animais , Bovinos , Doenças dos Bovinos/patologia , Mucosa Intestinal/patologia , Mucosa Intestinal/ultraestrutura , Feminino , Hemorragia Gastrointestinal/veterinária , Hemorragia Gastrointestinal/patologia , Microscopia Eletrônica de Transmissão/veterinária , Intestino Delgado/patologia , Imuno-Histoquímica/veterinária , Enteropatias/veterinária , Enteropatias/patologia
6.
Acta Neuropathol Commun ; 12(1): 88, 2024 Jun 05.
Artigo em Inglês | MEDLINE | ID: mdl-38840253

RESUMO

Huntington's disease (HD) is an inherited neurodegenerative disorder caused by an expanded CAG repeat in the coding sequence of huntingtin protein. Initially, it predominantly affects medium-sized spiny neurons (MSSNs) of the corpus striatum. No effective treatment is still available, thus urging the identification of potential therapeutic targets. While evidence of mitochondrial structural alterations in HD exists, previous studies mainly employed 2D approaches and were performed outside the strictly native brain context. In this study, we adopted a novel multiscale approach to conduct a comprehensive 3D in situ structural analysis of mitochondrial disturbances in a mouse model of HD. We investigated MSSNs within brain tissue under optimal structural conditions utilizing state-of-the-art 3D imaging technologies, specifically FIB/SEM for the complete imaging of neuronal somas and Electron Tomography for detailed morphological examination, and image processing-based quantitative analysis. Our findings suggest a disruption of the mitochondrial network towards fragmentation in HD. The network of interlaced, slim and long mitochondria observed in healthy conditions transforms into isolated, swollen and short entities, with internal cristae disorganization, cavities and abnormally large matrix granules.


Assuntos
Modelos Animais de Doenças , Doença de Huntington , Imageamento Tridimensional , Mitocôndrias , Animais , Doença de Huntington/patologia , Doença de Huntington/genética , Doença de Huntington/metabolismo , Mitocôndrias/ultraestrutura , Mitocôndrias/patologia , Mitocôndrias/metabolismo , Imageamento Tridimensional/métodos , Camundongos , Camundongos Transgênicos , Encéfalo/patologia , Encéfalo/ultraestrutura , Encéfalo/metabolismo , Microscopia Eletrônica/métodos , Masculino , Neurônios/patologia , Neurônios/ultraestrutura , Neurônios/metabolismo
7.
J Neurosci ; 44(23)2024 Jun 05.
Artigo em Inglês | MEDLINE | ID: mdl-38839340

RESUMO

A decade ago, in 2013, and over the course of 4 summer months, three separate observations were reported that each shed light independently on a new molecular organization that fundamentally reshaped our perception of excitatory synaptic transmission (Fukata et al., 2013; MacGillavry et al., 2013; Nair et al., 2013). This discovery unveiled an intricate arrangement of AMPA-type glutamate receptors and their principal scaffolding protein PSD-95, at synapses. This breakthrough was made possible, thanks to advanced super-resolution imaging techniques. It fundamentally changed our understanding of excitatory synaptic architecture and paved the way for a brand-new area of research. In this Progressions article, the primary investigators of the nanoscale organization of synapses have come together to chronicle the tale of their discovery. We recount the initial inquiry that prompted our research, the preceding studies that inspired our work, the technical obstacles that were encountered, and the breakthroughs that were made in the subsequent decade in the realm of nanoscale synaptic transmission. We review the new discoveries made possible by the democratization of super-resolution imaging techniques in the field of excitatory synaptic physiology and architecture, first by the extension to other glutamate receptors and to presynaptic proteins and then by the notion of trans-synaptic organization. After describing the organizational modifications occurring in various pathologies, we discuss briefly the latest technical developments made possible by super-resolution imaging and emerging concepts in synaptic physiology.


Assuntos
Receptores de AMPA , Sinapses , Receptores de AMPA/metabolismo , Receptores de AMPA/química , Sinapses/metabolismo , Sinapses/ultraestrutura , Animais , Humanos , Transmissão Sináptica/fisiologia , Nanoestruturas/química
8.
Biochemistry (Mosc) ; 89(4): 674-687, 2024 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-38831504

RESUMO

Chromatin is an epigenetic platform for implementation of DNA-dependent processes. Nucleosome, as a basic level of chromatin compaction, largely determines its properties and structure. In the study of nucleosomes structure and functions physicochemical tools are actively used, such as magnetic and optical "tweezers", "DNA curtains", nuclear magnetic resonance, X-ray crystallography, and cryogenic electron microscopy, as well as optical methods based on Förster resonance energy transfer. Despite the fact that these approaches make it possible to determine a wide range of structural and functional characteristics of chromatin and nucleosomes with high spatial and time resolution, atomic force microscopy (AFM) complements the capabilities of these methods. The results of structural studies of nucleosome focusing on the AFM method development are presented in this review. The possibilities of AFM are considered in the context of application of other physicochemical approaches.


Assuntos
Microscopia de Força Atômica , Nucleossomos , Nucleossomos/química , Nucleossomos/ultraestrutura , Nucleossomos/metabolismo , Microscopia de Força Atômica/métodos , Humanos , DNA/química , DNA/metabolismo , Animais
9.
J Vis Exp ; (207)2024 May 24.
Artigo em Inglês | MEDLINE | ID: mdl-38856213

RESUMO

Volume electron microscopy (Volume EM) has emerged as a powerful tool for visualizing the 3D structure of cells and tissues with nanometer-level precision. Within the retina, various types of neurons establish synaptic connections in the inner and outer plexiform layers. While conventional EM techniques have yielded valuable insights into retinal subcellular organelles, their limitation lies in providing 2D image data, which can hinder accurate measurements. For instance, quantifying the size of three distinct synaptic vesicle pools, crucial for synaptic transmission, is challenging in 2D. Volume EM offers a solution by providing large-scale, high-resolution 3D data. It is worth noting that sample preparation is a critical step in Volume EM, significantly impacting image clarity and contrast. In this context, we outline a sample preparation protocol for the 3D reconstruction of photoreceptor axon terminals in the retina. This protocol includes three key steps: retina dissection and fixation, sample embedding processes, and selection of the area of interest.


Assuntos
Retina , Retina/ultraestrutura , Animais , Microscopia Eletrônica/métodos , Imageamento Tridimensional/métodos , Camundongos , Microscopia Eletrônica de Volume
10.
Tissue Cell ; 88: 102427, 2024 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-38833940

RESUMO

Exosomes which are tiny extracellular vesicles (30-150 nm), transport vital proteins and gene materials such as miRNA, mRNA, or DNA, whose role in cell communication and epithelia regulation is critical. Many techniques have been developed as a result of studying exosomes' biochemical and physicochemical properties, although there is still no standard method to isolate exosomes simply with high yield. Commercial kits have gained popularity for exosome extraction despite concerns about their effectiveness in scientific research. On the other hand, ultracentrifugation remains the gold standard isolation method. This study compares these two common exosome isolation methods to determine their impact on the quality and quantity of exosomes isolated from bone marrow (BM) and Wharton's jelly (WJ)-derived mesenchymal stem cells. Isolated exosomes from the two sources of the cell's conditioned medium by two methods (polymer kit and ultracentrifuge) were characterized using western blotting, scanning electron microscopy (SEM), dynamic light scattering (DLS), and the Bradford assay. Western blot analysis confirmed separation efficiency based on CD81 and CD63 markers, with the absence of calnexin serving as a negative control. The Morphology of exosomes studied by SEM image analysis revealed a similar round shape appearance and their sizes (30-150 nm) were the same in both isolation techniques. The DLS analysis of the sample results was consistent with the SEM ones, showing a similar size range and very low disparity. The exosome protein content concentration analysis revealed that exosomes isolated by the polymer-based kits contained higher protein concentration density and purity (p <0.001). In general, though the protein yield was higher when the polymer-based kits were used, there were no significant differences in morphology, or size between WJ-derived and BM-derived exosomes, regardless of the isolation method employed.


Assuntos
Células da Medula Óssea , Exossomos , Células-Tronco Mesenquimais , Ultracentrifugação , Geleia de Wharton , Células-Tronco Mesenquimais/metabolismo , Células-Tronco Mesenquimais/citologia , Exossomos/metabolismo , Exossomos/ultraestrutura , Exossomos/química , Humanos , Ultracentrifugação/métodos , Geleia de Wharton/citologia , Geleia de Wharton/metabolismo , Células da Medula Óssea/metabolismo , Células da Medula Óssea/citologia , Polímeros/química
11.
Sci Rep ; 14(1): 13469, 2024 06 12.
Artigo em Inglês | MEDLINE | ID: mdl-38866846

RESUMO

Caudofoveata are molluscs that protect their vermiform body with a scleritome, a mosaic of unconnected blade/lanceolate-shaped aragonite sclerites. For the species Falcidens gutturosus and Scutopus ventrolineatus we studied the crystallographic constitution and crystal orientation texture of the sclerites and the scleritome with electron-backscatter-diffraction (EBSD), laser-confocal-microscopy (LCM) and field-emission electron microscopy (FE-SEM) imaging. Each sclerite is an aragonite single crystal that is completely enveloped by an organic sheath. Adjacent sclerites overlap laterally and vertically are, however, not connected to each other. Sclerites are thickened in their central portion, relative to their periphery. Thickening increases also from sclerite tip towards its base. Accordingly, cross-sections through a sclerite are straight at its tip, curved and bent towards the sclerite base. Irrespective of curved sclerite morphologies, the aragonite lattice within the sclerite is coherent. Sclerite aragonite is not twinned. For each sclerite the crystallographic c-axis is parallel to the morphological long axis of the sclerite, the a-axis is perpendicular to its width and the b-axis is within the width of the sclerite. The single-crystalinity of the sclerites and their mode of organization in the scleritome is outstanding. Sclerite and aragonite arrangement in the scleritome is not given by a specific crystal growth mode, it is inherent to the secreting cells. We discuss that morphological characteristics of the sclerites and crystallographic preferred orientation (texture) of sclerite aragonite is not the result of competitive growth selection. It is generated by the templating effect of the organic substance of the secreting cells and associated extracellular biopolymers.


Assuntos
Exoesqueleto , Carbonato de Cálcio , Moluscos , Animais , Exoesqueleto/química , Exoesqueleto/ultraestrutura , Moluscos/química , Carbonato de Cálcio/química , Cristalografia , Microscopia Eletrônica de Varredura
12.
Science ; 384(6700): 1064-1065, 2024 Jun 07.
Artigo em Inglês | MEDLINE | ID: mdl-38843349

RESUMO

Lacrymaria olor cytoskeleton and membrane "origami" enables rapid cell hyperextension.


Assuntos
Cilióforos , Citoesqueleto , Membrana Celular/ultraestrutura , Citoesqueleto/ultraestrutura , Cilióforos/fisiologia , Cilióforos/ultraestrutura
13.
Acta Neuropathol Commun ; 12(1): 94, 2024 Jun 12.
Artigo em Inglês | MEDLINE | ID: mdl-38867338

RESUMO

Down syndrome (DS) is a common genetic condition caused by trisomy of chromosome 21. Among their complex clinical features, including musculoskeletal, neurological, and cardiovascular disabilities, individuals with DS have an increased risk of developing progressive dementia and early-onset Alzheimer's disease (AD). This dementia is attributed to the increased gene dosage of the amyloid-ß (Aß) precursor protein gene, the formation of self-propagating Aß and tau prion conformers, and the deposition of neurotoxic Aß plaques and tau neurofibrillary tangles. Tau amyloid fibrils have previously been established to adopt many distinct conformations across different neurodegenerative conditions. Here, we report the characterization of brain samples from four DS cases spanning 36-63 years of age by spectral confocal imaging with conformation-specific dyes and cryo-electron microscopy (cryo-EM) to determine structures of isolated tau fibrils. High-resolution structures revealed paired helical filament (PHF) and straight filament (SF) conformations of tau that were identical to those determined from AD cases. The PHFs and SFs are made of two C-shaped protofilaments, each containing a cross-ß/ß-helix motif. Similar to filaments from AD cases, most filaments from the DS cases adopted the PHF form, while a minority (approximately 20%) formed SFs. Samples from the youngest individual with no documented dementia had sparse tau deposits. To isolate tau for cryo-EM from this challenging sample we used a novel affinity-grid method involving a graphene oxide surface derivatized with anti-tau antibodies. This method improved isolation and revealed that primarily tau PHFs and a minor population of chronic traumatic encephalopathy type II-like filaments were present in this youngest case. These findings expand the similarities between AD and DS to the molecular level, providing insight into their related pathologies and the potential for targeting common tau filament folds by small-molecule therapeutics and diagnostics.


Assuntos
Doença de Alzheimer , Microscopia Crioeletrônica , Síndrome de Down , Proteínas tau , Humanos , Síndrome de Down/patologia , Síndrome de Down/metabolismo , Proteínas tau/metabolismo , Proteínas tau/ultraestrutura , Microscopia Crioeletrônica/métodos , Pessoa de Meia-Idade , Doença de Alzheimer/patologia , Doença de Alzheimer/metabolismo , Feminino , Adulto , Masculino , Emaranhados Neurofibrilares/patologia , Emaranhados Neurofibrilares/metabolismo , Encéfalo/patologia , Encéfalo/metabolismo , Encéfalo/ultraestrutura
14.
Biol Pharm Bull ; 47(6): 1163-1171, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-38880624

RESUMO

The vital role of bile canaliculus (BC) in liver function is closely related to its morphology. Electron microscopy has contributed to understanding BC morphology; however, its invasiveness limits its use in living specimens. Here, we report non-invasive characterization of BC formation using refractive index (RI) tomography. First, we investigated and characterized the RI distribution of BCs in two-dimensional (2D) cultured HepG2 cells. BCs were identified based on their distinct morphology and functionality, as confirmed using a fluorescence-labeled bile acid analog. The RI distribution of BCs exhibited three common features: (1) luminal spaces with a low RI between adjacent hepatocytes; (2) luminal spaces surrounded by a membranous structure with a high RI; and (3) multiple microvillus structures with a high RI within the lumen. Second, we demonstrated the characterization of BC structures in a three-dimensional (3D) culture model, which is more relevant to the in vivo environment but more difficult to evaluate than 2D cultures. Various BC structures were identified inside HepG2 spheroids with the three features of RI distribution. Third, we conducted comparative analyses and found that the BC lumina of spheroids had higher circularity and lower RI standard deviation than 2D cultures. We also addressed comparison of BC and intracellular lumen-like structures within a HepG2 spheroid, and found that the BC lumina had higher RI and longer perimeter than intracellular lumen-like structures. Our demonstration of the non-destructive, label-free visualization and quantitative characterization of living BC structures will be a basis for various hepatological and pharmaceutical applications.


Assuntos
Canalículos Biliares , Humanos , Células Hep G2 , Refratometria/métodos , Esferoides Celulares/ultraestrutura , Tomografia/métodos , Hepatócitos/ultraestrutura , Técnicas de Cultura de Células
15.
Science ; 384(6700): eadk5511, 2024 Jun 07.
Artigo em Inglês | MEDLINE | ID: mdl-38843314

RESUMO

Fundamental limits of cellular deformations, such as hyperextension of a living cell, remain poorly understood. Here, we describe how the single-celled protist Lacrymaria olor, a 40-micrometer cell, is capable of reversibly and repeatably extending its necklike protrusion up to 1200 micrometers in 30 seconds. We discovered a layered cortical cytoskeleton and membrane architecture that enables hyperextensions through the folding and unfolding of cellular-scale origami. Physical models of this curved crease origami display topological singularities, including traveling developable cones and cytoskeletal twisted domain walls, which provide geometric control of hyperextension. Our work unravels how cell geometry encodes behavior in single cells and provides inspiration for geometric control in microrobotics and deployable architectures.


Assuntos
Forma Celular , Extensões da Superfície Celular , Cilióforos , Citoesqueleto , Membrana Celular/ultraestrutura , Citoesqueleto/ultraestrutura , Cilióforos/citologia , Cilióforos/fisiologia , Extensões da Superfície Celular/ultraestrutura , Microtúbulos/ultraestrutura
16.
Anat Histol Embryol ; 53(4): e13068, 2024 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-38837763

RESUMO

A comprehensive light and ultrastructural examination of the cornea in Domestic Pigs (Sus scrofa domesticus) revealed four distinct layers: the anterior epithelium, corneal stroma, Descemet's membrane and endothelium. Although Bowman's layer was not distinctly identified through histology, histochemical analysis indicated the presence of a rudimentary Bowman's layer, possibly vestigial from evolution. Scanning electron microscopy of the outer corneal surface unveiled two cell types, characterized by micro-projections, with light cells exhibiting shorter, thicker projections compared to dark cells. Examination of the inner surface via scanning electron microscopy demonstrated an endothelial layer devoid of cilia and microvilli, yet faint round to oval elevations were observed, potentially representing cell nuclei. Transmission electron microscopy unveiled that basal cells of the anterior epithelium closely adhered to the basement membrane, featuring half desmosomes along the basal surface. These basal cells extensively interconnected through interdigitations and a few desmosomes. The superficial cell layer consisted of a few rows of closely attached flat cells, forming a leak-proof layer with zona occludens. The outermost cells of this layer displayed fine projections to enhance the surface area, facilitating tear film distribution. At lower magnification, Transmission electron microscopy of the corneal stroma revealed alternating light and dark bands, with light bands representing transverse sections of collagen fibril lamellae and dark bands corresponding to longitudinal or oblique sections. Spindle-shaped keratocytes (fibroblasts) were identified as the primary stromal cells, intermingled between the lamellae, and featured long processes in close contact with neighbouring keratocytes. Overall, the histomorphology of the pig cornea resembles that of the human cornea except indistinct Bowman's membrane. This detailed understanding of the normal corneal structure in pigs hold great significance for biomedical research, providing a valuable reference for studies involving this animal model.


Assuntos
Córnea , Microscopia Eletrônica de Varredura , Microscopia Eletrônica de Transmissão , Sus scrofa , Animais , Córnea/ultraestrutura , Córnea/anatomia & histologia , Microscopia Eletrônica de Transmissão/veterinária , Microscopia Eletrônica de Varredura/veterinária , Sus scrofa/anatomia & histologia , Substância Própria/ultraestrutura , Endotélio Corneano/ultraestrutura , Endotélio Corneano/anatomia & histologia , Epitélio Corneano/ultraestrutura , Lâmina Limitante Posterior/ultraestrutura , Lâmina Limitante Posterior/anatomia & histologia , Suínos/anatomia & histologia , Lâmina Limitante Anterior/ultraestrutura , Lâmina Limitante Anterior/anatomia & histologia
17.
Parasitol Res ; 123(6): 237, 2024 Jun 10.
Artigo em Inglês | MEDLINE | ID: mdl-38856825

RESUMO

Mastophorus muris (Gmelin, 1790) is a globally distributed parasitic nematode of broad range mammals. The taxonomy within the genus Mastophorus and the cryptic diversity among the genus are controversial among taxonomists. This study provides a detailed morphological description of M. muris from Mus musculus combined with a molecular phylogenetic approach. Moreover, descriptions and molecular data of M. muris from non-Mus rodents and wildcats complement our findings and together provide new insights into their taxonomy. The analysis of M. muris was based on light microscopy and scanning electron microscopy. The morphological description focused on the dentition pattern of the two trilobed pseudolabia. Additionally, we described the position of the vulva, arrangement of caudal pairs of papillae, spicules and measured specimens from both sexes and the eggs. For the molecular phylogenetic approach, we amplified the small subunit ribosomal RNA gene and the internal transcribed spacer, and the cytochrome c oxidase subunit 1. Mastophorus morphotypes based on dentition patterns and phylogenetic clustering indicate a subdivision of the genus in agreement with their host. We recognize two groups without a change to formal taxonomy: One group including those specimens infecting Mus musculus, and the second group including organisms infecting non-Mus rodents. Our genetic and morphological data shed light into the cryptic diversity within the genus Mastopohorus. We identified two host-associated groups of M. muris. The described morphotypes and genotypes of M. muris allow a consistent distinction between host-associated parasites.


Assuntos
Microscopia Eletrônica de Varredura , Filogenia , Animais , Feminino , Masculino , Camundongos , Spiruroidea/classificação , Spiruroidea/genética , Spiruroidea/anatomia & histologia , Spiruroidea/isolamento & purificação , Spiruroidea/ultraestrutura , Complexo IV da Cadeia de Transporte de Elétrons/genética , Variação Genética , Análise de Sequência de DNA , Microscopia , DNA de Helmintos/genética , DNA Ribossômico/genética , DNA Espaçador Ribossômico/genética , Análise por Conglomerados , Dados de Sequência Molecular
18.
Nat Commun ; 15(1): 4959, 2024 Jun 11.
Artigo em Inglês | MEDLINE | ID: mdl-38862465

RESUMO

Intrastromal cell therapy utilizing quiescent corneal stromal keratocytes (qCSKs) from human donor corneas emerges as a promising treatment for corneal opacities, aiming to overcome limitations of traditional surgeries by reducing procedural complexity and donor dependency. This investigation demonstrates the therapeutic efficacy of qCSKs in a male rat model of corneal stromal opacity, underscoring the significance of cell-delivery quality and keratocyte differentiation in mediating corneal opacity resolution and visual function recovery. Quiescent CSKs-treated rats display improvements in escape latency and efficiency compared to wounded, non-treated rats in a Morris water maze, demonstrating improved visual acuity, while stromal fibroblasts-treated rats do not. Advanced imaging, including multiphoton microscopy, small-angle X-ray scattering, and transmission electron microscopy, revealed that qCSK therapy replicates the native cornea's collagen fibril morphometry, matrix order, and ultrastructural architecture. These findings, supported by the expression of keratan sulfate proteoglycans, validate qCSKs as a potential therapeutic solution for corneal opacities.


Assuntos
Diferenciação Celular , Ceratócitos da Córnea , Opacidade da Córnea , Animais , Masculino , Opacidade da Córnea/patologia , Ratos , Ceratócitos da Córnea/metabolismo , Humanos , Modelos Animais de Doenças , Substância Própria/metabolismo , Substância Própria/ultraestrutura , Substância Própria/efeitos dos fármacos , Acuidade Visual , Recuperação de Função Fisiológica , Córnea/patologia , Córnea/metabolismo , Ratos Sprague-Dawley
19.
J Morphol ; 285(6): e21742, 2024 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-38837266

RESUMO

Chaetae are among the most extensively studied structures in polychaetes, serving as a defining morphological trait for annelids. Capitella teleta stands out as one of the few established annelid models for developmental and morphological studies, thus receiving significant scholarly attention. In this study, we unveil a previously unnoticed glandular structure associated with chaetae within the larvae of C. teleta. Our investigations demonstrate the absence of comparable structures in the chaetal follicles of adults and juveniles (older than 1 week), as well as during active chaetogenesis, underscoring the transient nature of these glands. This indicates that larval chaetal follicles transform into a gland that later disappears. Utilizing histology and transmission electron microscopy, we characterized these glands. Our findings underscore the diversity of chaetal ultrastructure in annelids and show that, even in well-studied species, novel morphological details can be found. We emphasize the importance of examining various life-history stages to capture such transient morphological features. This work lays a crucial morphological foundation and deepens our understanding of chaetae and chaetogenesis in C. teleta, paving the way for more accurate interpretations of future experimental studies on chaetogenesis in this species.


Assuntos
Larva , Poliquetos , Animais , Poliquetos/anatomia & histologia , Poliquetos/crescimento & desenvolvimento , Poliquetos/ultraestrutura , Larva/ultraestrutura , Larva/anatomia & histologia , Larva/crescimento & desenvolvimento , Microscopia Eletrônica de Transmissão , Anelídeos/anatomia & histologia , Anelídeos/ultraestrutura , Anelídeos/crescimento & desenvolvimento
20.
J Obes ; 2024: 7204607, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-38831961

RESUMO

Obesity is a complex chronic disease characterized by excess body fat (adipose) that is harmful to health and has been a major global health problem. It may be associated with several diseases, such as nonalcoholic fatty liver disease (NAFLD). Polyunsaturated fatty acids (PUFA) are lipid mediators that have anti-inflammatory characteristics and can be found in animals and plants, with capybara oil (CO) being a promising source. So, we intend to evaluate the hepatic pathophysiological alterations in C57Bl/6 mice with NAFLD, caused by obesity, and the possible beneficial effects of OC in the treatment of this disease. Eighteen 3-month-old male C57Bl/6 mice received a control or high-fat diet for 18 weeks. From the 15th to the 18th week, the animals received treatment-through orogastric gavage-with placebo or free capybara oil (5 g/kg). Parameters inherent to body mass, glucose tolerance, evaluation of liver enzymes, percentage of hepatic steatosis, oxidative stress, the process of cell death with the apoptotic biomarkers (Bax, Bcl2, and Cytochrome C), and the ultrastructure of hepatocytes were analyzed. Even though the treatment with CO was not able to disassemble the effects on the physiological parameters, it proved to be beneficial in reversing the morphological and ultrastructural damage present in the hepatocytes. Thus, demonstrating that CO has beneficial effects in reducing steatosis and the apoptotic pathway, it is a promising treatment for NAFLD.


Assuntos
Apoptose , Fígado , Hepatopatia Gordurosa não Alcoólica , Óleos , Roedores , Camundongos Endogâmicos C57BL , Hepatopatia Gordurosa não Alcoólica/etiologia , Hepatopatia Gordurosa não Alcoólica/terapia , Masculino , Animais , Camundongos , Hepatócitos/efeitos dos fármacos , Hepatócitos/patologia , Hepatócitos/ultraestrutura , Óleos/farmacologia , Óleos/uso terapêutico , Obesidade/complicações , Apoptose/efeitos dos fármacos , Fígado/efeitos dos fármacos , Fígado/patologia , Fígado/ultraestrutura , Oxirredutases/metabolismo , Ativação Enzimática/efeitos dos fármacos , Estresse Oxidativo/efeitos dos fármacos
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