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1.
Sci Rep ; 13(1): 375, 2023 Jan 07.
Artigo em Inglês | MEDLINE | ID: mdl-36611035

RESUMO

Symbiotic associations are dynamic systems influenced by both intrinsic and extrinsic factors. Here we describe for the first time the developmental and seasonal changes of the funicular bodies in the bryozoan Dendrobeania fruticosa, which are unique temporary organs of cheilostome bryozoans containing prokaryotic symbionts. Histological and ultrastructural studies showed that these organs undergo strong seasonal modification in the White Sea during the ice-free period. Initially (in June) they play a trophic function and support the development of a large population of bacteria. From June to September, both funicular bodies and bacteria show signs of degradation accompanied by development of presumed virus-like particles (VLPs); these self-organize to hollow spheres inside bacteria and are also detected outside of them. Although the destruction of bacteria coincides with the development of VLPs and spheres, the general picture differs considerably from the known instances of bacteriophagy in bryozoans. We broadly discuss potential routes of bacterial infection in Bryozoa and question the hypothesis of vertical transfer, which, although widely accepted in the literature, is contradicted by molecular, morphological and ecological evidence.


Assuntos
Briozoários , Animais , Briozoários/ultraestrutura , Estações do Ano , Simbiose
2.
Vet Parasitol ; 314: 109868, 2023 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-36603452

RESUMO

Encystation in Cryptocaryon irritans is a fundamental process for environmental resistance and development. Autophagy participates in the encystation of ciliates, and rapamycin can induce autophagy in the cells. A set of genes and metabolites related to autophagy and encystation are highly elaborative. The existence of these genes and metabolites and their role are well characterized. However, little is known about their role in protozoans such as ciliates. The newly produced C. irritans protomonts were exposed to an optimal concentration of rapamycin (1400 nM), and the survival, encystation, microstructure/ultrastructure, transcriptomic and metabolomic profile in treated and control protomonts were investigated. The results showed that exposure of protomonts to rapamycin at 4 h significantly lowered the survival and encystation rates to 91.62 % and 98.44 % compared to the control group (100 %, p ≤ 0.05). Morphological alterations observed in light microscopy and transmission electron microscopy (TEM) demonstrated that the drug significantly changed cell symmetry by causing the formation of various autophagic vacuoles/vesicles. The transcriptome sequencing of rapamycin-treated protomont revealed that 2249 (1837 up-regulated and 977 down-regulated) differentially expressed genes (DEGs) were identified. Kyoto Encyclopedia of Genes and Genomes (KEGG) analysis showed that 226 DEGs were successfully annotated in 21 pathways (p˂0.05), including most enriched pathways apoptosis and phagosome with 25 and 24 DEGs, respectively. Most unigenes were assigned to autophagy-related pathways; 24 DEGs were classified into phagosomes, and 15 DEGs were assigned to lysosome pathways. Cytoskeleton and cell progression-associated genes were down-regulated. Besides, cell death-inducing proteins were up-regulated. The metabolomic analysis revealed exposure to rapamycin treatment enhanced protomont metabolites, including L-Cysteine, which is related to autophagy. Rapamycin had influenced the gene and metabolites of protomont; activating autophagy with inhibition of mechanistic target of rapamycin, (mTOR). The process negatively influences protomont morphology, encystation, and survival. Further autophagy-related gene silencing can be investigated via genome sequencing of C. irritans to study encystation.


Assuntos
Infecções por Cilióforos , Cilióforos , Hymenostomatida , Animais , Cilióforos/genética , Cilióforos/ultraestrutura , Infecções por Cilióforos/veterinária , Perfilação da Expressão Gênica/veterinária , Hymenostomatida/genética , Metabolômica , Transcriptoma , Sirolimo/farmacologia
3.
J Cell Biol ; 222(3)2023 Mar 06.
Artigo em Inglês | MEDLINE | ID: mdl-36637807

RESUMO

To enable rapid propagation of action potentials, axons are ensheathed by myelin, a multilayered insulating membrane formed by oligodendrocytes. Most of the myelin is generated early in development, resulting in the generation of long-lasting stable membrane structures. Here, we explored structural and dynamic changes in central nervous system myelin during development. To achieve this, we performed an ultrastructural analysis of mouse optic nerves by serial block face scanning electron microscopy (SBF-SEM) and confocal time-lapse imaging in the zebrafish spinal cord. We found that myelin undergoes extensive ultrastructural changes during early postnatal development. Myelin degeneration profiles were engulfed and phagocytosed by microglia using exposed phosphatidylserine as one "eat me" signal. In contrast, retractions of entire myelin sheaths occurred independently of microglia and involved uptake of myelin by the oligodendrocyte itself. Our findings show that the generation of myelin early in development is an inaccurate process associated with aberrant ultrastructural features that require substantial refinement.


Assuntos
Microglia , Bainha de Mielina , Nervo Óptico , Peixe-Zebra , Animais , Camundongos , Axônios/ultraestrutura , Microglia/ultraestrutura , Bainha de Mielina/ultraestrutura , Oligodendroglia/ultraestrutura , Nervo Óptico/ultraestrutura , Microscopia Eletrônica de Varredura , Fagocitose , Imagem com Lapso de Tempo
4.
Nature ; 613(7943): 383-390, 2023 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-36599982

RESUMO

Specific, regulated modification of RNAs is important for proper gene expression1,2. tRNAs are rich with various chemical modifications that affect their stability and function3,4. 7-Methylguanosine (m7G) at tRNA position 46 is a conserved modification that modulates steady-state tRNA levels to affect cell growth5,6. The METTL1-WDR4 complex generates m7G46 in humans, and dysregulation of METTL1-WDR4 has been linked to brain malformation and multiple cancers7-22. Here we show how METTL1 and WDR4 cooperate to recognize RNA substrates and catalyse methylation. A crystal structure of METTL1-WDR4 and cryo-electron microscopy structures of METTL1-WDR4-tRNA show that the composite protein surface recognizes the tRNA elbow through shape complementarity. The cryo-electron microscopy structures of METTL1-WDR4-tRNA with S-adenosylmethionine or S-adenosylhomocysteine along with METTL1 crystal structures provide additional insights into the catalytic mechanism by revealing the active site in multiple states. The METTL1 N terminus couples cofactor binding with conformational changes in the tRNA, the catalytic loop and the WDR4 C terminus, acting as the switch to activate m7G methylation. Thus, our structural models explain how post-translational modifications of the METTL1 N terminus can regulate methylation. Together, our work elucidates the core and regulatory mechanisms underlying m7G modification by METTL1, providing the framework to understand its contribution to biology and disease.


Assuntos
Microscopia Crioeletrônica , Proteínas de Ligação ao GTP , Metilação , Metiltransferases , Processamento Pós-Transcricional do RNA , RNA de Transferência , Humanos , Domínio Catalítico , Cristalografia por Raios X , Proteínas de Ligação ao GTP/química , Proteínas de Ligação ao GTP/metabolismo , Proteínas de Ligação ao GTP/ultraestrutura , Metiltransferases/química , Metiltransferases/metabolismo , Metiltransferases/ultraestrutura , RNA de Transferência/química , RNA de Transferência/metabolismo , RNA de Transferência/ultraestrutura , S-Adenosil-Homocisteína/metabolismo , S-Adenosilmetionina/metabolismo , Especificidade por Substrato , Biocatálise
5.
Int J Mol Sci ; 24(2)2023 Jan 05.
Artigo em Inglês | MEDLINE | ID: mdl-36674522

RESUMO

The need for new non-animal and non-petroleum-based materials is strongly emphasized in the sustainable and green economy. Waste materials have proven a valuable resource in this regard. In fact, there have been quite a large number of goods obtained from wastes called "Vegan leather" that have gained the clothing market's attention in recent years. In practice, they are mostly composites of waste materials like cactus, pineapples, or, eventually, apples with polymers like polyurethane or polyvinyl chloride. The article presents the results of work aimed at obtaining a material based entirely on natural, biodegradable raw materials. Bacterial cellulose produced as a byproduct of the fermentation carried out by SCOBY was modified with glycerol and then altered by the entrapment of apple powder. The effect of introducing apple powder into the SCOBY culture media on the mechanical properties of the obtained bacterial cellulose was also evaluated The resulting material acquired new mechanical characteristics that are advantageous in terms of strength. Microscopic observation of the apple powder layer showed that the coverage was uniform. Different amounts of apple powder were used to cover the cellulose surface from 10 to 60%, and it was found that the variant with 40% of this powder was the most favorable in terms of mechanical strength. Also, the application of the created material as a card folder showed that it is durable in use and retains its functional characteristics for at least 1 month. The mechanical properties of modified bacterial cellulose were favorably affected by the entrapment of apple powder on its surface, and as a result, a novel material with functional characteristics was obtained.


Assuntos
Materiais Biocompatíveis , Malus , Pós , Celulose/ultraestrutura , Polímeros
6.
Fish Shellfish Immunol ; 132: 108480, 2023 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-36513323

RESUMO

Melanomacrophagic centers (MMCs) were studied in the hepatocytes of zebrafish using transmission electron microscope (TEM). The MMCs with irregular or amoeboid nucleus were located in the hepatocytes adjacent to the bile canaliculi. Several engulfed structures were present in the cytoplasm of MMCs. The most frequent observation was the presence of mitochondria, ranging in size from small to giant, with distorted shape and inconspicuous cristae. Occasionally the fragments of erythrocytes were found. The rough endoplasmic reticulum (rER) showed whirling around the mitochondria and lipid droplets, forming membrane-like structures. The damaged mitochondria were invaded by the lysosomes, and this was covered by a membrane led to the formation of lipofuscin. Four different types of lipofuscins were observed; namely, (1) granular with/without vacuoles of high electron-density, (2) homogenous surrounded by indistinct limiting membrane, (3) lamellated structures similar to inner matrix and cristae of mitochondria, and, (4) compound structure made by the combinations of first 3 types, (granular and homogenous, granular and lamellated, homogenous and lamellated). The present evidence suggests that MMCs in the hepatocytes of zebrafish perform continuous functions of removal of the damaged cellular organelles. The lipofuscin formation work in coordination with the cellular players of immune system and remove pathogens and maintain the internal homeostasis of cells.


Assuntos
Lipofuscina , Peixe-Zebra , Animais , Hepatócitos/ultraestrutura , Lisossomos , Retículo Endoplasmático/ultraestrutura
7.
Methods Mol Biol ; 2557: 161-209, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-36512216

RESUMO

The Golgi complex (GC) is an essential organelle of the eukaryotic exocytic pathway. It has a very complexed structure and thus localization of its resident proteins is not trivial. Fast development of microscopic methods generates a huge difficulty for Golgi researchers to select the best protocol to use. Modern methods of light microscopy, such as super-resolution light microscopy (SRLM) and electron microscopy (EM), open new possibilities in analysis of various biological structures at organelle, cell, and organ levels. Nowadays, new generation of EM methods became available for the study of the GC; these include three-dimensional EM (3DEM), correlative light-EM (CLEM), immune EM, and new estimators within stereology that allow realization of maximal goal of any morphological study, namely, to achieve a three-dimensional model of the sample with optimal level of resolution and quantitative determination of its chemical composition. Methods of 3DEM have partially overlapping capabilities. This requires a careful comparison of these methods, identification of their strengths and weaknesses, and formulation of recommendations for their application to cell or tissue samples. Here, we present an overview of 3DEM methods for the study of the GC and some basics for how the images are formed and how the image quality can be improved.


Assuntos
Elétrons , Complexo de Golgi , Microscopia Eletrônica , Complexo de Golgi/ultraestrutura , Organelas , Algoritmos
8.
Plant Cell Environ ; 46(2): 650-664, 2023 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-36482792

RESUMO

To study viral infection, the direct structural visualization of the viral life cycle consisting of virus attachment, entry, replication, assembly and transport is essential. Although conventional electron microscopy (EM) has been extremely helpful in the investigation of virus-host cell interactions, three-dimensional (3D) EM not only provides important information at the nanometer resolution, but can also create 3D maps of large volumes, even entire virus-infected cells. Here, we determined the ultrastructural details of tomato spotted wilt virus (TSWV)-infected plant cells using focused ion beam scanning EM (FIB-SEM). The viral morphogenesis and dynamic transformation of paired parallel membranes (PPMs) were analyzed. The endoplasmic reticulum (ER) membrane network consisting of tubules and sheets was related to viral intracellular trafficking and virion storage. Abundant lipid-like bodies, clustering mitochondria, cell membrane tubules, and myelin-like bodies were likely associated with viral infection. Additionally, connecting structures between neighboring cells were found only in infected plant tissues and showed the characteristics of tubular structure. These novel connections that formed continuously in the cell wall or were wrapped by the cell membranes of neighboring cells appeared frequently in the large-scale 3D model, suggesting additional strategies for viral trafficking that were difficult to distinguish using conventional EM.


Assuntos
Tospovirus , Vírus , Tospovirus/ultraestrutura , Plantas , Retículo Endoplasmático/metabolismo , Microscopia Eletrônica
9.
J Cell Biol ; 222(2)2023 Feb 06.
Artigo em Inglês | MEDLINE | ID: mdl-36469001

RESUMO

Volume electron microscopy is an important imaging modality in contemporary cell biology. Identification of intracellular structures is a laborious process limiting the effective use of this potentially powerful tool. We resolved this bottleneck with automated segmentation of intracellular substructures in electron microscopy (ASEM), a new pipeline to train a convolutional neural network to detect structures of a wide range in size and complexity. We obtained dedicated models for each structure based on a small number of sparsely annotated ground truth images from only one or two cells. Model generalization was improved with a rapid, computationally effective strategy to refine a trained model by including a few additional annotations. We identified mitochondria, Golgi apparatus, endoplasmic reticulum, nuclear pore complexes, caveolae, clathrin-coated pits, and vesicles imaged by focused ion beam scanning electron microscopy. We uncovered a wide range of membrane-nuclear pore diameters within a single cell and derived morphological metrics from clathrin-coated pits and vesicles, consistent with the classical constant-growth assembly model.


Assuntos
Processamento de Imagem Assistida por Computador , Microscopia Eletrônica , Redes Neurais de Computação , Clatrina , Retículo Endoplasmático/ultraestrutura , Complexo de Golgi/ultraestrutura , Microscopia Eletrônica/métodos , Mitocôndrias/ultraestrutura , Poro Nuclear/ultraestrutura , Cavéolas/ultraestrutura , Biologia Celular
10.
J Exp Med ; 220(2)2023 Feb 06.
Artigo em Inglês | MEDLINE | ID: mdl-36469302

RESUMO

Arachnoid granulations (AG) are poorly investigated. Historical reports suggest that they regulate brain volume by passively transporting cerebrospinal fluid (CSF) into dural venous sinuses. Here, we studied the microstructure of cerebral AG in humans with the aim of understanding their roles in physiology. We discovered marked variations in AG size, lobation, location, content, and degree of surface encapsulation. High-resolution microscopy shows that AG consist of outer capsule and inner stromal core regions. The fine and porous framework suggests uncharacterized functions of AG in mechanical CSF filtration. Moreover, internal cytokine and immune cell enrichment imply unexplored neuroimmune properties of these structures that localize to the brain-meningeal lymphatic interface. Dramatic age-associated changes in AG structure are additionally identified. This study depicts for the first time microscopic networks of internal channels that communicate with perisinus spaces, suggesting that AG subserve important functions as transarachnoidal flow passageways. These data raise new theories regarding glymphatic-lymphatic coupling and mechanisms of CSF antigen clearance, homeostasis, and diseases.


Assuntos
Medula Óssea , Vasos Linfáticos , Humanos , Aracnoide-Máter/ultraestrutura , Dura-Máter , Sistema Linfático
11.
J Affect Disord ; 324: 259-269, 2023 Mar 01.
Artigo em Inglês | MEDLINE | ID: mdl-36584708

RESUMO

BACKGROUND: Diffusion tensor imaging (DTI) is recommended as a sensitive method to explore white matter (WM) microstructural alterations. Cerebral small vessel disease (CSVD) may be accompanied by extensive WM microstructural deterioration, while cerebral microbleeds (CMBs) are an important factor affecting CSVD. METHODS: Fractional anisotropy (FA), mean diffusivity (MD), axial diffusivity (AD) and radial diffusivity (RD) images from 49 CSVD patients with CMBs (CSVD-c), 114 CSVD patients without CMBs (CSVD-n), and 83 controls were analyzed using DTI-derived tract-based spatial statistics to detect WM diffusion changes among groups. RESULTS: Compared with the CSVD-n and control groups, the CSVD-c group showed a significant FA decrease and AD, RD and MD increases mainly in the cognitive and sensorimotor-related WM tracts. There was no significant difference in any diffusion metric between the CSVD-n and control groups. Furthermore, the widespread regional diffusion alterations among groups were significantly correlated with cognitive parameters in both the CSVD-c and CSVD-n groups. Notably, we applied the multiple kernel learning technique in multivariate pattern analysis to combine multiregion and multiparameter diffusion features, yielding an average accuracy >77 % for three binary classifications, which showed a considerable improvement over the single modality approach. LIMITATIONS: We only grouped the study according to the presence or absence of CMBs. CONCLUSIONS: CSVD patients with CMBs have extensive WM microstructural deterioration. Combining DTI-derived diffusivity and anisotropy metrics can provide complementary information for assessing WM alterations associated with cognitive dysfunction and serve as a potential discriminative pattern to detect CSVD at the individual level.


Assuntos
Hemorragia Cerebral , Doenças de Pequenos Vasos Cerebrais , Disfunção Cognitiva , Substância Branca , Humanos , Anisotropia , Hemorragia Cerebral/complicações , Hemorragia Cerebral/diagnóstico por imagem , Doenças de Pequenos Vasos Cerebrais/complicações , Doenças de Pequenos Vasos Cerebrais/diagnóstico por imagem , Disfunção Cognitiva/diagnóstico por imagem , Disfunção Cognitiva/etiologia , Imagem de Tensor de Difusão/métodos , Substância Branca/diagnóstico por imagem , Substância Branca/patologia , Substância Branca/ultraestrutura
12.
Biochim Biophys Acta Mol Basis Dis ; 1868(1): 166279, 2022 01 01.
Artigo em Inglês | MEDLINE | ID: mdl-34600082

RESUMO

The tumor stroma plays a pivotal role in colon cancer genesis and progression. It was observed that collagen fibers in the extracellular matrix (ECM) of cancer stroma, undergo a strong remodeling. These fibrous proteins result more aligned and compact than in physiological conditions, creating a microenvironment that favors cancer development. In this work, micro-FTIR spectroscopy was applied to investigate the chemical modifications in the tumor stroma. Using Fuzzy C-means clustering, mean spectra from diseased and normal stroma were compared and collagen was found to be responsible for the main differences between them. Specifically, the modified absorptions at 1203, 1238, 1284 cm-1 and 1338 cm-1 wavenumbers, were related to the amide III band and CH2 bending of side chains. These signals are sensitive to the interactions between the α-chains in the triple helices of collagen structure. This provided robust chemical evidence that in cancer ECM, collagen fibers are more parallelized, stiff and ordered than in normal tissue. Principal Component Analysis (PCA) applied to the spectra from malignant and normal stroma confirmed these findings. Using LDA (Linear Discriminant Analysis) classification, the absorptions 1203, 1238, 1284 and 1338 cm-1 were examined as spectral biomarkers, obtaining quite promising results. The use of a PCA-LDA prediction model on samples with moderate tumor degree further showed that the stroma chemical modifications are more indicative of malignancy compared to the epithelium. These preliminary findings have shown that micro-FTIR spectroscopy, focused on collagen signals, could become a promising tool for colon cancer diagnosis.


Assuntos
Carcinogênese/genética , Carcinoma/diagnóstico , Colágeno/química , Neoplasias do Colo/diagnóstico , Espectroscopia de Infravermelho com Transformada de Fourier , Carcinoma/química , Carcinoma/patologia , Colágeno/ultraestrutura , Colo/química , Colo/patologia , Neoplasias do Colo/química , Neoplasias do Colo/patologia , Epitélio/química , Epitélio/patologia , Matriz Extracelular/química , Matriz Extracelular/patologia , Humanos , Análise de Componente Principal , Microambiente Tumoral/genética
13.
Harmful Algae ; 120: 102338, 2022 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-36470602

RESUMO

Thirty-four strains of Heterocapsa were established from Malaysian waters and their morphologies were examined by light, scanning, and transmission electron microscopy. Three species, H. bohaiensis, H. huensis, and H. rotundata, and three new species, H. borneoensis sp. nov., H. limii sp. nov., and H. iwatakii sp. nov. were described in this study. The three species were differentiated morphologically by unique characteristics of cell size, shape, displacement of the cingulum, shape and position of nucleus, the number and position of pyrenoids, and body scale ultrastructure. The species delimitations were robustly supported by the molecular data. A light-microscopy-based key to species of Heterocapsa is established, with two major groups, i.e., species with a single pyrenoid, and species with multiple pyrenoids. Bioassays were conducted by exposing Artemia nauplii to Heterocapsa densities of 1-5 × 105 cells mL-1, and treatments exposed to H. borneoensis showed naupliar mortality, while no naupliar death was observed in the treatments exposed to cells of H. bohaiensis, H. huensis, H. limii, and H. iwatakii. Naupliar death was observed during the initial 24 h for both tested H. borneoensis strains, and mortality rates increased up to 50% after 72-h exposure. This study documented for the first time the diversity and cytotoxic potency of Heterocapsa species from Malaysian waters.


Assuntos
Dinoflagelados , Malásia , Filogenia , Dinoflagelados/ultraestrutura , Microscopia Eletrônica de Transmissão
14.
Zh Nevrol Psikhiatr Im S S Korsakova ; 122(12): 128-137, 2022.
Artigo em Russo | MEDLINE | ID: mdl-36537643

RESUMO

OBJECTIVE: To study the ultrastructure of microglia adjacent to oligodendrocytes in white matter of the prefrontal cortex in continuous schizophrenia (CSch) as compared to controls and attack-like schizophrenia (ASch) and to perform correlation analysis between the parameters of microglia and adjacent oligodendrocytes previously detected in both clinical types of schizophrenia. MATERIAL AND METHODS: Electron microscopic morphometric study of microglia adjacent to oligodendrocytes was performed in postmortem white matter of the prefrontal cortex (BA10) in 9 cases of CSch, 8 cases of ASch and 20 healthy controls. Group comparisons were made by ANCOVA and Pearson correlation analyses. RESULTS: The reduction of volume fraction (Vv) and the number of mitochondria in microglia was found in elderly subjects (>50 y.o.) as compared to young controls (60%, p<0.05), and the increase in these parameters of lipofuscin granules were detected in elderly subjects as compared to elderly controls in CSch (470%, 606%, p<0.001). Vv and the number of mitochondria in microglia correlated negatively with area of heterochromatin in microglia (r≥-0.7, p<0.05), and area of lipofuscin correlated positively with area of heterochromatin in microglia (r=0.76, p<0.05) and with illness duration (r=0.7, p<0.05) only in the CSch group. The numerical density of microglia was not changed in both schizophrenia groups. Area of heterochromatin was increased in both groups as compared to controls (p<0.05) and correlated negatively with the numerical density of microglia in the CSch group. The number of mitochondria in oligodendrocytes (reduced in CSch) correlated positively with the number of mitochondria in microglia and negatively with Vv of lipofuscin granules in microglia and with area of microglial nucleus only in the CSch group. CONCLUSION: Specific features of CSch as compared to ASch might be associated with the disturbances of mitochondrial and lipid metabolism in microglia, dysfunction of nucleus and accelerated aging of microglia that might lead to alterations of mitochondrial metabolism in oligodendrocytes.


Assuntos
Esquizofrenia , Substância Branca , Humanos , Esquizofrenia/metabolismo , Microglia , Substância Branca/ultraestrutura , Heterocromatina/metabolismo , Lipofuscina/metabolismo , Oligodendroglia/ultraestrutura , Córtex Pré-Frontal/ultraestrutura
15.
Adv Anat Embryol Cell Biol ; 235: 37-42, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-36525109

RESUMO

Among the multiple and intriguing roles of centrosomes in cellular functions is the ubiquitin-proteasome-mediated protein degradation. It has been shown that proteasomes are concentrated at the mammalian centrosome which led to further studies to view the centrosome as a proteolytic center (Wojcik et al. 1996; Wigley et al. 1999; reviewed in Badano et al. 2005). Proteasomal components that are concentrated around the centrosome include ubiquitin, the 20S and 19S subunits of the proteasome, as well as the E3 enzyme parkin. These proteasomal components colocalize with the centrosomal marker γ-tubulin and co-purify with γ-tubulin in the centrosomal fractions after sucrose-gradient ultracentrifugation (Wigley et al. 1999). The localization, accumulation, and concentration of proteasomal components around centrosomes appear to be microtubule independent which has been shown experimentally by inhibiting microtubule functions. When intracellular levels of misfolded proteins were experimentally increased by either proteasome inhibition with drugs such as lactacystin, or by overexpression of misfolded mutant proteins, the centrosome-associated proteasome network became expanded and proteolytic components were recruited from the cytosol without involvement of microtubules. These studies revealed a critical role of centrosomes in the organization and subcellular localization of proteasomes (Wigley et al. 1999; Fabunmi et al. 2000).


Assuntos
Complexo de Endopeptidases do Proteassoma , Tubulina (Proteína) , Animais , Humanos , Tubulina (Proteína)/metabolismo , Complexo de Endopeptidases do Proteassoma/metabolismo , Proteólise , Centrossomo/metabolismo , Centrossomo/ultraestrutura , Ubiquitina/metabolismo , Mamíferos/metabolismo
16.
Dis Aquat Organ ; 152: 159-168, 2022 Dec 22.
Artigo em Inglês | MEDLINE | ID: mdl-36546688

RESUMO

A study targeting the etiology of severe anaemia that sporadically occurred in laboratory-bred cyprinid hybrids resulted in a diagnosis of a Mycoplasma-like organism selectively invading the cytoplasm of erythrocytes. Despite the fact that there was a concurrent yeast infection in moribund anaemic hybrids, the primary role in the development of anaemia was assigned to the Mycoplasma-like organism due to its regular occurrence in erythrocytes of both the moribund hybrids and hybrids that were free of yeast infection yet showed early to advanced symptoms of the disease. Novel data on the Mycoplasma-like organism's cytoskeleton were obtained from ultrathin sections of affected erythrocytes. An ultrastructural study of the concurrent yeast infection in moribund hybrids manifesting the most advanced anaemia revealed the presence of Titan cells in ascitic fluid. The original findings presented in this study underline the diagnostic relevance of transmission electron microscopy in the research of similar infections.


Assuntos
Anemia , Infecções por Mycoplasma , Mycoplasma , Animais , Infecções por Mycoplasma/diagnóstico , Infecções por Mycoplasma/veterinária , Saccharomyces cerevisiae , Anemia/veterinária , Mycoplasma/ultraestrutura , Eritrócitos/ultraestrutura
17.
Georgian Med News ; (331): 95-100, 2022 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-36539139

RESUMO

A feature of recent decades is the gradual increase in the level of male infertility, one of the important causes of which, of course, is endocrine dysfunction of various origins. Therefore, the aim of the study was to establish the features of the rearrangement of the testicle's cellular elements of white rats with the introduction of high doses of prednisolone. An ultrastructural study was carried out on 42 male rats. It has been established that long-term introduction of high doses of prednisolone promotes the activation of spermatogenesis with a progressive increase in immature forms of germ cells and a simultaneous decrease in the specific number of mature spermatozoa. Activation of spermatogenesis occurs against the background of increased blood circulation in the testicles with an increase in the blood supply to their vessels, especially in the early period (7-14 days from the start of use), which may be a consequence of the direct effects of prednisolone stimulating blood circulation. In the long term (14-28 days) there is a decrease in the throughput of small arteries and arterioles against the background of venous stasis, as well as the rate of activation of spermatogenesis, which may be a reaction to the overload of the capillary bed of the testicles and cause further development of organ's ischemia with it.


Assuntos
Prednisolona , Testículo , Masculino , Animais , Prednisolona/farmacologia , Espermatozoides/ultraestrutura , Espermatogênese/fisiologia , Epitélio
18.
Sci Rep ; 12(1): 21297, 2022 12 09.
Artigo em Inglês | MEDLINE | ID: mdl-36494564

RESUMO

Staphylococcus virus ΦSA012 has a wide host range and efficient lytic activity. Here, we assessed the biological stability of ΦSA012 against temperature, freeze-thawing, and pH to clinically apply the phage. In addition, inoculation of ΦSA012 through i.p. and i.v. injections into mice revealed that phages were reached the limit of detection in serum and accumulated notably spleens without inflammation at 48 h post-inoculation. Furthermore, inoculation of ΦSA012 through s.c. injections in mice significantly induced IgG, which possesses neutralizing activity against ΦSA012 and other Staphylococcus viruses, ΦSA039 and ΦMR003, but not Pseudomonas viruses ΦS12-3 and ΦR18 or Escherichia viruses T1, T4, and T7 in vitro. Immunoelectron microscopic analysis showed that purified anti-phage IgG recognizes the long-tail fiber of staphylococcus viruses. Although S. aureus inoculation resulted in a 25% survival rate in a mouse i.p. model, ΦSA012 inoculation (i.p.) improved the survival rate to 75%; however, the survival rate of ΦSA012-immunized mice decreased to less than non-immunized mice with phage i.v. injection at a MOI of 100. These results indicated that ΦSA012 possesses promise for use against staphylococcal infections but we should carefully address the appropriate dose and periods of phage administration. Our findings facilitate understandings of staphylococcus viruses for phage therapy.


Assuntos
Terapia por Fagos , Infecções Estafilocócicas , Camundongos , Animais , Terapia por Fagos/métodos , Fagos de Staphylococcus/ultraestrutura , Staphylococcus aureus , Staphylococcus , Infecções Estafilocócicas/terapia , Myoviridae/ultraestrutura , Imunoglobulina G
19.
Nature ; 612(7941): 714-719, 2022 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-36477531

RESUMO

Molecular phylogenetics of microbial eukaryotes has reshaped the tree of life by establishing broad taxonomic divisions, termed supergroups, that supersede the traditional kingdoms of animals, fungi and plants, and encompass a much greater breadth of eukaryotic diversity1. The vast majority of newly discovered species fall into a small number of known supergroups. Recently, however, a handful of species with no clear relationship to other supergroups have been described2-4, raising questions about the nature and degree of undiscovered diversity, and exposing the limitations of strictly molecular-based exploration. Here we report ten previously undescribed strains of microbial predators isolated through culture that collectively form a diverse new supergroup of eukaryotes, termed Provora. The Provora supergroup is genetically, morphologically and behaviourally distinct from other eukaryotes, and comprises two divergent clades of predators-Nebulidia and Nibbleridia-that are superficially similar to each other, but differ fundamentally in ultrastructure, behaviour and gene content. These predators are globally distributed in marine and freshwater environments, but are numerically rare and have consequently been overlooked by molecular-diversity surveys. In the age of high-throughput analyses, investigation of eukaryotic diversity through culture remains indispensable for the discovery of rare but ecologically and evolutionarily important eukaryotes.


Assuntos
Eucariotos , Cadeia Alimentar , Microbiologia , Filogenia , Organismos Aquáticos/classificação , Organismos Aquáticos/genética , Organismos Aquáticos/ultraestrutura , Biodiversidade , Ecologia , Eucariotos/classificação , Eucariotos/genética , Eucariotos/ultraestrutura , Células Eucarióticas/classificação , Células Eucarióticas/metabolismo , Células Eucarióticas/ultraestrutura , Comportamento Predatório , Especificidade da Espécie
20.
Adv Exp Med Biol ; 1395: 309-313, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-36527654

RESUMO

Connexin 43 (Cx43) is a multifunction protein that forms gap junction channels and hemichannels and is suggested to play an essential role in oxygen-glucose deprivation, induced via neuroinflammation during astrocytoma expansion into healthy tissue. To prove this assumption we studied connexin 43 localisation and ultrastructure of gap junctions in samples of malignant brain tumour (anaplastic astrocytomas grade III). For confocal laser microscopy, vibratome sections of tumour fragments were incubated in a mixture of primary antibodies to connexin 43 and glial fibrillary acidic protein (GFAP), then in a mixture of secondary antibodies conjugated with a fluorescent label. After the immunofluorescence study, sections were washed in phosphate buffer, additionally postfixed with 1% OsO4 solution, dehydrated and embedded in epoxy resin by a plane-parallel method. Ultra-thin sections obtained from these samples were contrasted with uranyl acetate and lead citrate and viewed under a Jem 1011 electron microscope. Confocal laser examination detected a positive reaction to Cx43 in the form of point fluorescence. These points were of various sizes. Most of them were localised around or at the intersection of small processes containing GFAP. Electron microscopy of the tumour samples containing the most significant number of Cx43 revealed single and closely spaced gap junctions with a typical ultrastructure on the processes and bodies of tumour cells. Sequential analysis in the fields of view revealed 62 gap junctions in the area of 100 µm2. Numerous gap junctions in anaplastic astrocytomas revealed in our study may indicate electrotonic and metabolic transmission between glioma cells, possibly promoting its progression.


Assuntos
Astrocitoma , Conexina 43 , Junções Comunicantes , Microscopia Confocal , Microscopia Eletrônica , Humanos , Astrocitoma/genética , Astrocitoma/metabolismo , Astrocitoma/patologia , Astrocitoma/ultraestrutura , Conexina 43/genética , Conexina 43/metabolismo , Conexina 43/ultraestrutura , Junções Comunicantes/genética , Junções Comunicantes/metabolismo , Junções Comunicantes/ultraestrutura , Lasers
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