Microscopy and Microanalysis最新文献

As the most common ectoparasites on mackerel icefish (Champsocephalus gunnari Lönnberg 1905), which has great economic and ecological importance in the Southern Ocean, parasitic copepods and leeches can significantly affect fish health and survival and thus influence the sustainable use of this commercial fishery resource. Accurate identification of these parasites is essential for understanding their specific impacts on hosts and ecosystems, as well as for developing effective fisheries management. This study investigated 34 ectoparasites from 28 C. gunnari specimens at South Georgia in August 2023 using microscopy and mitochondrial cytochrome c oxidase I (CO I) markers. Morphological analysis tentatively identified 10 leeches as Notobdella nototheniae and 24 copepods as Eubrachiella antarctica. Microscopic examinations and morphological measurements revealed marked differences between male and female copepods. Additionally, CO I sequencing confirmed the leeches as N. nototheniae (98.81% similarity) but suggested the copepods were Parabrachiella merluccii (81.97-82.25% similarity). All sequences have been uploaded to Genbank. Maximum Likelihood phylogenetic trees were also constructed using the CO I sequence of both ectoparasites. The 10 leeches were identified as N. nototheniae, and the 24 copepods were E. antarctica in this study.

Three-dimensional (3D)-cultured tonsil-derived mesenchymal stem cells (TMSCs) show high therapeutic efficacy in murine colitis. We evaluated the in vivo localization and formation of 3D-TMSCs using electron microscopy. Mice with dextran sulfate sodium-induced chronic colitis received intraperitoneal injections of 3D-TMSCs. The formation and localization of TMSC aggregates in the peritoneal cavity were assessed by immunofluorescence and electron microscopy. In mice treated with 3D-TMSCs, white spherical aggregates attached to the peritoneal cavity were observed. Immunofluorescence staining revealed the co-localization of human-origin TMSCs and mouse immune cells within these aggregates. The presence of human glyceraldehyde-3-phosphate dehydrogenase (GAPDH) confirmed the presence of human-origin TMSCs in the aggregates. Electron microscopy revealed that 3D-TMSCs were covered with mouse immune cells. The presence of pseudopodia and microvilli facilitated cell-to-cell connections, indicating a complex integrated structure rather than a mere collection of TMSCs. After 15 days, rough endoplasmic reticulum and mitochondria were identified within the cytoplasm of the TMSCs. Prominent autophagosomes and extracellular vesicles were observed within the intraperitoneal 3D-TMSC aggregates. These findings underscore the viability and paracrine effects of 3D-TMSCs and support their potential as an advanced therapeutic option for treating inflammatory bowel disease.

Sterile inflammation (SI) is a common pathology in numerous diseases, as a cause or consequence. Hypothyroidism (HT) is an inflammatory condition with complications stemming from excess cytokine release. A thyroidectomy-induced HT rat model was used to evaluate the impact of human umbilical cord blood-derived mesenchymal stem cells (hUCB-MSCs) on splenic inflammation and histoarchitecture. Thirty male Wistar rats were allocated equally as Sham, HT and HT+hUCB-MSCs groups. HT was confirmed by serum-free thyroxin 3, thyroxin 4 and thyroid stimulating hormone levels. Splenic homogenates were analyzed for oxidative stress and inflammation markers. Histopathological and immunohistochemical analyses were conducted to assess splenic stromal and parenchymal elements, high mobility group box 1 (HMGB1), toll-like receptor 4 (TLR4), pro-inflammatory cytokine immune expression, in addition to the innate and adaptive immune cell populations and their proliferative and apoptotic activities. Correlations between HMGB1 level and various parameters were evaluated. hUCB-MSCs significantly downregulated HMGB1, TLR4 and pro-inflammatory cytokine immune expression and attenuated immune cell activation through increasing antioxidant status, attenuating lipid peroxidation, and modulating cellular proliferation and apoptosis, thus protecting the spleen against HT-induced structural damage and immune cell overactivation. Collectively, our results demonstrate the therapeutic efficacy of hUCB-MSCs in mitigating HT-induced SI.

Momentum-resolved scanning transmission electron microscopy (MRSTEM) is a powerful phase-contrast technique that can map lateral magnetic and electric fields ranging from the micrometer to the subatomic scale. Resolving fields ranging from a few nanometers to a few hundred nanometers, as well as across material interfaces, is particularly important since these fields often determine the functional properties of devices. However, it is also challenging since they are orders of magnitude smaller than atomic electric fields. Thus, subtle changes in diffraction conditions lead to significant changes in the measured MRSTEM signal. One established approach to partially overcome this problem is precession electron diffraction, in which the incident electron beam is continuously precessed while precession-averaged diffraction patterns are acquired. Here, we present an alternative approach in which we sequentially tilt the incident electron beam and record a full diffraction pattern for each tilt and spatial position. This approach requires no hardware modification of the instrument and enables the use of arbitrary beam tilt patterns that can be optimized for specific applications. Furthermore, recording diffraction patterns for every beam tilt allows access to additional information. In this work, we use this information to create virtual large-angle convergent beam electron diffraction patterns to assess MRSTEM data quality and improve field measurements by applying different data analysis methods beyond simple averaging. The presented data acquisition concept can readily be applied to other 4D-STEM applications.

Chionanthus filiformis (Vell.) P.S. Green (Oleaceae) is an endemic species of the Atlantic Rainforest. This study provides a comprehensive morphoanatomical description of its leaves and stems, integrating light microscopy, field emission scanning electron microscopy, histochemical, and phytochemical tests. To the best of our knowledge, this is the first report on the stem anatomy and histochemistry of the species. Morphologically, the leaves are simple, opposite, dark green on the adaxial surface, and pale green on the abaxial surface. Key anatomy diagnostic characteristics comprise straight to wavy anticlinal cell walls on the adaxial epidermis, stomatal dimensions (22.99 ± 2.09 µm × 20.10 ± 1.79 µm), a stomatal index of 14.835% ± 1.75, dorsiventral mesophyll, and vascular system organization in the midrib and petiole. The morphotypes and the distribution of crystals were essentially relevant for species identification. Histochemical analysis confirmed the presence of lipophilic and phenolic compounds, neutral polysaccharides, and starch grains. Phytochemical screening detected anthraquinones, coumarins, flavonoids, steroids, and tannins, whereas two-dimensional chromatography further identified specific subgroups of coumarins, flavonoids, and triterpenoids. These findings provide novel insights into the anatomy and chemical composition of C. filiformis, contributing to its taxonomic characterization and increasing the knowledge of Chionanthus genus.

Marine phytoplankton form functional biominerals with intricate morphologies and architectures. Coccolithophores occupy a special position among these organisms because of their production of intricate calcite scales, called coccoliths. Although coccolith morphologies differ across different species, crystals are organized around an organic matrix systematically to form an arrangement of astounding symmetry. We demonstrate the opportunities emerging from four-dimensional scanning transmission electron microscopy (4D-STEM), to spatially solve the crystallography of such biominerals. Through the development of a computational pipeline, which automatically solves the orientation at image pixels corresponding to crystals, we can map the orientation of the entangled and overlapping crystalline building blocks composing the coccolith. The present work exemplifies how parallel real space and diffraction space recordings can facilitate and improve the throughput of deciphering the complex network of biomineral superstructures.

Alveolar echinococcosis, caused by Echinococcus multilocularis, exhibits significant species-dependent susceptibility. This study compared the early hepatic tissue responses to E. multilocularis in highly susceptible cotton rats (Sigmodon hispidus) and laboratory mice (DBA/2 and AKR/N). Following oral administration of E. multilocularis eggs, cotton rats developed a greater number of hepatic lesions within 2 weeks, whereas mice required 4 weeks to develop smaller lesions. Histopathology revealed accelerated multilocular cyst formation in cotton rats. Unlike mice, which formed dense collagenous layers isolating cysts, cotton rats lacked adventitial layers despite similar fibrotic thickness. Immunohistochemistry revealed abundant CD206+ macrophages at cyst peripheries in cotton rats, engaging in efferocytosis of apoptotic neutrophils with expression of TGF-β, galectin-3, and VEGF. Efferocytic macrophages expressed collagen-degrading enzymes (cathepsin K and MMP9) and the growth factor FGF2. These findings suggest that efferocytosis by neutrophils drives macrophages toward an anti-inflammatory M2 phenotype, leading to immune evasion, ineffective fibrotic encapsulation, and parasitic growth. Given the wide distribution of cotton rats in the Americas and the expanding range of E. multilocularis, their hypersusceptibility raises significant public health concerns as rodents could serve as an intermediate host. These insights may inform new strategies for host-parasite interactions and the control of alveolar echinococcosis.

Electron beam-induced current (EBIC) imaging is a well-established scanning electron microscope (SEM) technique used to analyze the behavior of microelectronic devices including solar cells. Recently, the application of EBIC imaging in an aberration-corrected scanning transmission electron microscope (STEM) has been demonstrated and offers great potential for the in situ study of electronic materials, correlating charge transport properties to atomic structural and elemental information. This work presents two ways to implement EBIC imaging in conventional SEM and STEM systems: one relying on the instrument's inherent scanning and imaging electronics and the other involving third-party systems usually available in electron microscopes. The implementation of lock-in EBIC in systems equipped with a fast beam blanker is also described. In addition, this work shows and discusses the different mechanisms at play in EBIC imaging and their dependence on beam energy, sample impedance, and electrical measurement configuration, providing researchers with the basic information needed to apply the technique to their research.