Search results for "electron microscopy"
showing 10 items of 706 documents
Dynamic Changes in Ultrastructure of the Primary Cilium in Migrating Neuroblasts in the Postnatal Brain
2019
New neurons, referred to as neuroblasts, are continuously generated in the ventricular-subventricular zone of the brain throughout an animal's life. These neuroblasts are characterized by their unique potential for proliferation, formation of chain-like cell aggregates, and long-distance and high-speed migration through the rostral migratory stream (RMS) toward the olfactory bulb (OB), where they decelerate and differentiate into mature interneurons. The dynamic changes of ultrastructural features in postnatal-born neuroblasts during migration are not yet fully understood. Here we report the presence of a primary cilium, and its ultrastructural morphology and spatiotemporal dynamics, in mig…
Evidence for pleural epithelial-mesenchymal transition in murine compensatory lung growth
2017
In many mammals, including rodents and humans, removal of one lung results in the compensatory growth of the remaining lung; however, the mechanism of compensatory lung growth is unknown. Here, we investigated the changes in morphology and phenotype of pleural cells after pneumonectomy. Between days 1 and 3 after pneumonectomy, cells expressing α-smooth muscle actin (SMA), a cytoplasmic marker of myofibroblasts, were significantly increased in the pleura compared to surgical controls (p < .01). Scanning electron microscopy of the pleural surface 3 days post-pneumonectomy demonstrated regions of the pleura with morphologic features consistent with epithelial-mesenchymal transition (EMT); nam…
The shape of synaptic ribbons in the rat pineal gland
1997
Under the transmission electron microscope, synaptic ribbons (SRs) of the mammalian pineal gland appear as rod-like organelles. Their three-dimensional structure is not precisely known. In the present study, pineal SRs were investigated using serial sections obtained from rats killed at noon and midnight. The shape of the SRs was reconstructed based on SR profile length and the number of sections in which the profiles were contained. The results obtained show that SRs are basically flat plate-like structures with polymorphic lateral edges. Reconstructions of SRs revealed that they had average dimensions of 300x150x35 nm and were 19.3% larger at night than at day; the difference in SR size p…
Bizarre alterations of the morphology of pineal synaptic bodies under constant light and an evaluation of suitable 3D-reconstruction software
2004
Three dimensional (3D) reconstruction and modelling software was evaluated to find a procedure suitable for visualization of small subcellular structures in transmission electron microscope images. The method applied in this study demonstrates bizarre alterations of the structure of synaptic bodies (SBs) in pinealocytes of the guinea-pig pineal gland caused by constant illumination. It can, in general, be used for any 3D reconstruction from serial sections. Pineal glands of five guinea-pigs (two kept under a LD cycle of 12:12 h; three kept in constant light, for 4 months) were investigated. SBs consist of an electron-dense centre with attached vesicles. Under normal lighting conditions most…
The study of Positive and Negative Affect in children and adolescents: New advances in a Spanish version of the PANAS
2019
The study of affective disorders among young population has become increasingly relevant in the last years. The PANAS is a widely used questionnaire devoted to assess positive and negative affect. The main purpose of the current study was to examine the psychometric properties of the Spanish version of the PANAS for children (PANAS). The sample consisted of 1032 children and adolescents aged between 10 and 15 years. The ESEM two factor model (Positive Affect and Negative Affect) was found as the most suitable model. The PANAS scores also showed acceptable internal consistency. The ESEM two factor model was invariant across gender and educational level. Results showed statistically significa…
Measuring Psychobiosocial States in Sport: Initial Validation of a Trait Measure
2016
We examined the item characteristics, the factor structure, and the concurrent validity of a trait measure of psychobiosocial states. In Study 1, Italian athletes (N = 342, 228 men, 114 women, Mage = 23.93, SD = 6.64) rated the intensity, the frequency, and the perceived impact dimensions of a psychobiosocial states scale, trait version (PBS-ST), which is composed of 20 items (10 functional and 10 dysfunctional) referring to how they usually felt before an important competition. In Study 2, the scale was cross validated in an independent sample (N = 251, 181 men, 70 women, Mage = 24.35, SD = 7.25). The concurrent validity of the PBS-ST scale scores were also examined in comparison with two …
Sex-related effects in the superhydrophobic properties of damselfly wings in young and old Calopteryx splendens.
2013
Numerous sex-related morphological adaptations are connected to reproductive behavior in animals. For example, females of some insect species can submerge during oviposition, which may lead to sex-related adaptations in the hydrophobicity (water-repellency) due to specialization of certain morphological structures. On the other hand, ageing can cause changes in hydrophobicity of the surface, because the morphological structures can wear with age. Here, we investigated sex-and age-related differences in wing hydrophobicity and in morphology (spine density, wax cover characteristics, size of females' pseudopterostigma) potentially related to hydrophobicity of Calopteryx splendens damselflies.…
Unstructural Biology of TRP Ion Channels: The Role of Intrinsically Disordered Regions in Channel Function and Regulation
2021
The first genuine high-resolution single particle cryo-electron microscopy structure of a membrane protein determined was a transient receptor potential (TRP) ion channel, TRPV1, in 2013. This methodical breakthrough opened up a whole new world for structural biology and ion channel aficionados alike. TRP channels capture the imagination due to the sheer endless number of tasks they carry out in all aspects of animal physiology. To date, structures of at least one representative member of each of the six mammalian TRP channel subfamilies as well as of a few non-mammalian families have been determined. These structures were instrumental for a better understanding of TRP channel function and …
Special considerations for studies of extracellular vesicles from parasitic helminths: A community-led roadmap to increase rigour and reproducibility.
2023
Over the last decade, research interest in defining how extracellular vesicles (EVs) shape cross-species communication has grown rapidly. Parasitic helminths, worm species found in the phyla Nematoda and Platyhelminthes, are well-recognised manipulators of host immune function and physiology. Emerging evidence supports a role for helminth-derived EVs in these processes and highlights EVs as an important participant in cross-phylum communication. While the mammalian EV field is guided by a community-agreed framework for studying EVs derived from model organisms or cell systems [e.g., Minimal Information for Studies of Extracellular Vesicles (MISEV)], the helminth community requires a supplem…
Synthesis of yttrium aluminum garnet nanoparticles in confined environment II: Role of the thermal treatment on the composition and microstructural e…
2017
Abstract Nanoparticles of yttrium aluminum garnet (YAG, Y 3 Al 5 O 12 ) have been obtained by thermal treatments, at several temperature in the range 400–950 °C, of the precursors synthetized via co-precipitation in water in oil microemulsion. The obtained nanoparticles have been characterized by means of X-ray Diffraction and Transmission Electron Microscopy coupled with Energy Dispersive X-ray Spectroscopy (EDS) and Select Area Electron Diffraction (SAED). Results show the phase evolution occurring to obtain not aggregated nanoparticles of YAG phase. A possible growth mechanism of YAG nanoparticles is discussed on the basis of observed particle microstructure and morphology. The results i…