Search Results (2,324)

Ultrastructure changes in S. aureus and E. faecalis bacteria incubated with synthetic cationic amphiphile DL₄12 and its hybrids with the natural monoterpene carvacrol were studied. The hybrid compounds DL₄CAR-6, DL₅CAR-6, DLpCAR-6, and DLoCAR-6 contained two carvacrol molecules and differed in central linker structure. The study was conducted on ultrathin sections of bacteria fixed by the Ryter–Kellenberger method and on a Jem 1400 transmission electron microscope (Jeol, Tokyo, Japan). Ultrastructure changes in S. aureus and E. faecalis incubated with compound DL₄12 were species-specific. Destructive changes in S. aureus cells when exposed to DL₄12 compound and all DL₄12-carvacrol hybrids did not differ. DL₄12 and DL₄12-carvacrol hybrids in E. faecalis cells damaged all structures except the cell wall. Compound DL₄12 and its hybrids disrupted the ultrastructure of nucleoid and DNA strands in both bacterial species. Complete disorganization of ribosomes in cells of both bacteria occurred upon incubation with compound DL₄12 and its carvacrol-bearing analog DL₄CAR-6. Inclusions in bacterial cells exposed to all compounds had the same ultrastructure. The study showed that all compounds used possess multitarget properties; the structure of the central linker of hybrid compounds plays a significant role in the nature of their damaging effect on S. aureus and E. faecalis cells. Full article

Objective: This study aimed to investigate erythrocyte morphological alterations in hematological malignancies, with particular emphasis on structural differences among leukemia subtypes and anemia. Materials and Methods: Peripheral blood samples were obtained from 60 patients, including individuals with anemia (n = 10), acute lymphoblastic leukemia (ALL, n = 15), acute myeloid leukemia (AML, n = 15), chronic lymphocytic leukemia (CLL, n = 15), and chronic myeloid leukemia (CML, n = 5), as well as 10 healthy controls. Erythrocyte morphology was evaluated using light microscopy and scanning electron microscopy. Morphological abnormalities, including loss of biconcavity, poikilocytosis, echinocyte transformation, burr cells, and stomatocytes, were assessed in accordance with International Council for Standardization in Haematology (ICSH)-based morphological definitions. Results: Distinct erythrocyte morphological alterations were observed across disease groups. AML cases demonstrated pronounced central depression-like or perforation-like structures and hypochromasia. Lymphoid malignancies, particularly ALL and CLL, exhibited increased echinocyte formation, whereas chronic leukemias showed a higher prevalence of stomatocytes and cup-shaped cells. Quantitative scoring indicated that loss of biconcavity was most prominent in anemia, followed by AML, CML, ALL, and CLL. Poikilocytosis was most frequent in anemia, followed by ALL, CLL, AML, and CML. Conclusions: The findings indicate that erythrocyte shape alterations are more heterogeneous and prominent in lymphoid leukemias, whereas myeloid leukemias exhibit distinct ultrastructural membrane abnormalities. Although studies focusing on erythrocyte morphology in leukemia remain limited, the present results provide a foundational morphological reference dataset that may support the development and validation of artificial intelligence-based diagnostic approaches. Further studies involving larger cohorts and expanded imaging analyses are warranted to improve diagnostic accuracy and translational applicability. Full article

Breast cancer is the most frequently diagnosed malignancy among women worldwide, with the luminal A subtype being the most prevalent. Several studies have reported a complex interplay between breast cancer cells and the local microbiome; however, the mechanisms by which tumor cell-secreted factors influence bacterial biological properties remain insufficiently explored. In this study, we established an in vitro model that partially recapitulates the luminal A breast cancer microenvironment by exposing three breast-associated bacterial species, Pseudomonas aeruginosa, Enterococcus faecalis, and Escherichia coli, to conditioned media (CM) derived from MCF-7 (tumor) or MCF-10A (non-tumor control) cell lines. A combination of complementary approaches, including ultrastructural morphological assessment, biofilm formation assays, antimicrobial susceptibility testing, and virulence gene abundance profiling by genomic qPCR, was employed to reveal distinct tumor-microbiota interactions. Exposure to MCF-7 CM induced dose-dependent structural alterations in P. aeruginosa and E. faecalis, with pronounced membrane blebbing and structural disruption in E. faecalis. Biofilm formation was differentially modulated in a species- and concentration-dependent manner, with a persistent increase observed in E. coli. Antibiotic susceptibility profiles were selectively altered in E. faecalis, which displayed increased sensitivity to vancomycin, penicillin, and imipenem, along with decreased sensitivity to chloramphenicol. P. aeruginosa exhibited increased sensitivity to imipenem along with reduced sensitivity to meropenem and gentamicin, whereas no significant changes were observed in E. coli. qPCR analyses demonstrated that MCF-7 CM was associated with enrichment of multiple virulence-associated genes (e.g., lasB, exoS, pilB, plcH, fsrC, esp, fimH, and papG), reflecting enhanced pathogenic and adhesive potential. Collectively, these findings suggest that luminal A breast cancer-derived factors can reprogram microbial phenotypes in a species-specific manner, providing mechanistic insight into breast tumor-microbiome crosstalk and a platform to explore microbiome-targeted interventions. Full article

Mitochondrial biogenesis requires coordinated expression from both nuclear and mitochondrial genomes. To understand the consequences of mitochondrial genome loss, we generated a mitochondrial DNA-depleted line (crm⁻) in Chlamydomonas reinhardtii via long-term ethidium bromide treatment. We then examined how mtDNA disruption affects mitochondrial ultrastructure, chloroplast function, and the mitochondrial transcription termination factor (mTERF) gene family. Our results reveal that mitochondrial dysfunction is associated with severe organelle remodeling, including mitochondrial elongation, matrix condensation, and cristae collapse. Consequently, mitochondria reduce the electron sink capacity which appears to over-reduce the chloroplast electron transport chain, correlating with causing damage to photosystem II (PSII), as indicated by higher plastoquinone PQ redox state and PSII excitation pressure and lower non-photochemical quantum yield [Y(NPQ)]. Furthermore, we identified and characterized eight nuclear-encoded mTERF genes in C. reinhardtii (CrmTERFs). Phylogenetic analysis grouped them into three clades with potential functional conservation. Collinearity analysis suggested potential evolutionary relationships between mTERF genes in Chlamydomonas and Marchantia polymorpha. Gene ontology annotation linked CrmTERFs to transcription termination and RNA biosynthesis regulation. Additionally, in silico prediction identified twelve putative miRNAs targeting seven of the eight CrmTERFs, with CrmTERF3 as the only exception, providing candidates for future experimental validation. This study provides the first comprehensive analysis of the nuclear encoded mTERF gene family in Chlamydomonas and demonstrates that mtDNA loss is correlated with mTERF genes expression, as well as mitochondrial structure and chloroplast photoprotective impairments. These findings suggest a potential role for CrmTERFs in mitochondrial retrograde signaling and organellar crosstalk, though functional validation is required to establish causality. Full article

Background: The interaction between keratinocytes and proinflammatory cytokines is essential in the development of psoriatic lesions. The synergism among these cytokines and their involvement in ferroptosis are not yet elucidated. This study aimed at evaluating the early impact of a complete proinflammatory microenvironment on keratinocyte differentiation, intercellular adhesion, proliferation, and induction of ferroptosis. Methods: HaCaT cells were differentiated with 1.8 mM CaCl₂ and treated with a cytokine combination (MIX) containing IL-17A, IL-22, IL-23, and TNF-alpha for 24 and 48 h. Claudin 1 (CLDN-1), Zonula Occludens 1 (ZO-1), and keratins (K)10/K14 expression was analyzed by immunofluorescence and immunoblot analysis, paralleled by proliferation and ultrastructural analysis. Ferroptosis was induced with erastin and RSL3 and evaluated by testing glutathione (GSH)/glutathione peroxidase 4 (GPX4) protein expression, GSH levels, cell availability/toxicity, intracellular iron and ATP levels. Results: After MIX incubation at T48, CLDN-1 and ZO-1 immunofluorescences were reduced in HaCaT cells, while K10 and K14 were unaffected. The proliferative activity was reduced. Psoriatic-like MIX triggered the ferroptotic pathway, as shown by the increase in intracellular iron levels as well as by the reduction in GPX4 protein expression, the decrease in GSH levels, cell availability, and ATP levels. Conclusions: This experimental model mimics the early pathogenetic processes underlying psoriatic plaque formation/progression paving the way for new therapeutic strategies. Full article

Plant microtechnique involves a sequence of skill-intensive histological procedures that often yield poorly reproducible images and limited quantitative information. Nevertheless, it provides an essential cellular and tissue context needed to understand biological functions. In this work, we present an optimized resin-based microtechnique that replaces paraffin embedding, incorporates a chemically activated adhesive treatment for glass slides, and develop a trichrome stain for resin sections. All these improvements enhanced section stability and image reproducibility, enabled a broader color palette with sharp contrast of tissues, cells and organelles, and selected ultrastructural features using light microscopy. Based on these preparations, a quantitative micrograph analysis workflow was developed based on image segmentation and feature extraction using MATLAB (R2024a) and Adobe Photoshop (CS6). This approach enables the measurement of a wide range of morphometric and compositional features, generating structured histological datasets that we refer to as plant histolomes. As an illustrative application, this workflow was applied to leaves from several model plants species and integrated multiple anatomical traits into a composite feature, the “C₄ Kranz-anatomy level”, enabling quantitative comparison along the C₃-C₄ anatomical transition. The resin-based microtechnique and the histolomics framework developed in this work provide a robust and reproducible basis for the quantitative plant histology, bridging classical microscopy with a data-driven tissue analysis. Full article

Research has demonstrated that axonal signaling processes are influenced by both static structural factors and dynamic metabolic and electro-dynamic processes. Imaging, computational modeling and research in molecular neuroscience have demonstrated that multiple processes contribute to axonal signal processing, including periodic rearrangement of cytoskeletal structures and membrane structures, and redistribution of ion channel clusters and organelles (such as mitochondria), which occur rapidly and transiently to modify excitability. The dynamics of energy production and distribution also vary between regions of the axon and at different time points during signal generation and transmission. Additionally, myelin-associated glia may temporarily modulate their metabolic and structural contributions to axonal conduction. Advanced AI-based techniques for mapping and simulating ultrastructure and the use of closed-loop perturbation experiments demonstrate that axons can generate multiple distinct electromechanical states, and therefore potentially influence both the timing of signals generated by the axon, the routing of signals to branches of the axon, and the robustness of signal propagation. While the existence of these adaptive microstates appears well established, there are many aspects of their influence on circuit level function that are poorly understood. In summary, these data support the concept that axonal conduction represents a continuum of reversible and state-dependent configurations generated by integrated interactions among molecular, structural and energetic processes. Therefore, this review will attempt to synthesize the available literature into a unified conceptual framework and identify areas of uncertainty that may direct future research into the adaptive processes underlying axonal computation. Full article

Background and Clinical Significance: Phosphoglyceride crystal deposition disease (PCDD) is an extremely rare condition characterized by the deposition of phosphoglyceride crystals, occasionally forming tumor like lesions that present significant diagnostic challenges. Here, we report, to our knowledge, the first documented recurrent case of PCDD confined to the mandible, which clinically and radiologically mimicked a malignant bone tumor. Case Presentation: An 80-year-old female patient presented with a progressively enlarging mandibular mass, and imaging studies demonstrated an osteolytic lesion with cortical bone destruction and marked fluorodeoxyglucose uptake on positron emission tomography-computed tomography, raising a strong suspicion of malignancy. Histopathological examination revealed foreign-body granulomatous inflammation with characteristic crystal deposition, and the diagnosis of PCDD was definitively established through the combined use of gold hydroxamic acid staining, Raman spectroscopy, and ultrastructural analysis. Although surgical excision with curettage was initially achieved, local recurrence was observed 6 years later, indicating the potential for long-term disease persistence. In addition, a comprehensive literature review conducted in accordance with the PRISMA guidelines was performed to summarize previously reported cases of PCDD, with particular attention to anatomical distribution, radiological characteristics, recurrence patterns, and proposed pathogenic mechanisms. The review confirmed the extreme rarity of mandibular involvement and demonstrated that recurrence can occur apparently even after surgical treatment. Conclusions: This case underscores the importance of a multimodal diagnostic strategy integrating imaging, histopathology, and spectroscopic analyses for the accurate identification of PCDD and highlights the necessity of histopathological confirmation to prevent unnecessary aggressive treatment. Full article

Objectives: Cerebral ischemia/reperfusion (IR) injury is characterized by excessive oxidative stress and activation of apoptotic pathways, which play a central role in neuronal loss and poor neurological outcomes. Modulation of these mechanisms represents a clinically relevant strategy for neuroprotection. This study aimed to investigate the neuroprotective effects of dexmedetomidine (Dex) on oxidative stress, apoptotic signaling, and neuronal integrity in an experimental rat model of cerebral IR injury. Materials and Methods: Female Wistar rats were assigned to control, IR, and IR+Dex groups. Transient cerebral ischemia was induced for 45 min followed by 2 h of reperfusion. Oxidative stress was evaluated using serum antioxidant enzyme activities (superoxide dismutase [SOD], catalase [CAT], glutathione peroxidase [GSH-Px]), total oxidant and antioxidant status (TOS, TAS), and lipid peroxidation levels (malondialdehyde [MDA]). Apoptotic signaling was assessed by histopathological examination, transmission electron microscopy, and immunohistochemical analysis of B-cell lymphoma 2 (Bcl-2), Bcl-2-associated X protein (Bax) and apoptotic peptidase activating factor-1 (APAF-1) expression, quantitatively evaluated using QuPath with statistical comparison between groups. Bioinformatic network analysis and molecular docking were performed to explore predicted interactions between Dex and apoptosis-related proteins. Results: Cerebral IR induced a marked oxidative imbalance, characterized by reduced antioxidant enzyme activities and increased lipid peroxidation. Dex treatment partially improved antioxidant capacity and reduced oxidative stress parameters. Histopathological and ultrastructural analyses demonstrated severe neuronal degeneration following IR, whereas Dex-treated rats exhibited attenuated neuronal damage and improved ultrastructural preservation. Immunohistochemical analysis showed increased Bax and APAF-1 expression and reduced Bcl-2 expression after IR; these alterations were significantly modulated toward control levels in the IR+Dex group. Bioinformatic analysis identified apoptosis-related pathways, including apoptosis, p53 signaling, and necroptosis, as significantly enriched, while molecular docking suggested stable predicted interactions between Dex and key apoptotic regulators. Conclusions: In this experimental rat cerebral IR model, Dex exerted partial but significant neuroprotective effects by attenuating oxidative stress, modulating apoptotic marker expression, and preserving neuronal morphology. These findings support the potential role of Dex as a neuroprotective agent in ischemia-related brain injury, warranting further translational investigation. Full article

Chloroplast development plays a crucial role in plant de-etiolation, a process in which plants switch from growth in darkness to light-driven development, known as photomorphogenesis. This study provides evidence that CIA2 (Chloroplast Import Apparatus 2) and CIL (CIA2-Like) contribute to chloroplast biogenesis, likely by affecting and regulating PSII activity and related gene expression. Although their precise molecular roles remain unclear, our findings support their possible involvement in chloroplast development. This is indicated by downregulation of foliar chlorophyll content, chlorophyll a fluorescence parameters, chloroplast size, and gene expression of PSII molecular markers in the cia2cil double mutant during de-etiolation. Chlorophyll a fluorescence and quantitative gene expression analysis during de-etiolation revealed a significant reduction in PSII maximal efficiency and non-photochemical quenching, as well as deregulated expression of genes such as LHCB2.1 and psbA. According to the immunoblotting and microscopy imaging results, there is an impaired function of PSII and a compromised ultrastructure of the chloroplast membranes in cia2cil plants. However, in CIA2p::CIA2_cia2cil and 35Sp::CIA2_cia2cil complementation lines, reversion of this phenotype was observed. These results suggest a supporting role for CIA2 and CIL in the plant de-etiolation process, expanding our understanding of chloroplast biogenesis regulation. Full article

The mitigation of toxic cyanobacterial blooms is a much-researched and ongoing challenge. Seasonal influences, microbial diversity, and the wide range of cyanotoxins known to be associated with cyanobacterial blooms add layers of complexity to these environmental threats. Strategies to remediate blooms must avoid inducing widespread cell lysis and the release of cyanotoxins, which would compound rather than address the problem. Bacterial isolates have been found to be effective in bloom mitigation and can impact the diversity associated with the bloom. The present study reports on the exposure of non-axenic cultures of colonial Microcystis sp. and filamentous Oscillatoria sp. isolated from dams in South Africa to low ratios of four antagonistic bacterial isolates for 4 days. TEM was used to assess ultrastructural changes, HPLC to determine the relative concentrations of microcystin-LR and RR, and next-generation sequencing (NGS) to explore possible shifts in diversity from control samples as a result of exposure to the biological control bacterial isolates used. Ultrastructurally, Microcystis showed greater signs of stress than cells of Oscillatoria, with isolate 1 (Aeromonas lacus) having the least effect overall, whilst Isolate B (Lysinibacillus) and 3Y (Pseudomonas sp.) induced cell lysis in Microcystis. All isolates reduced the concentration of the toxic microcystin-LR, while the -RR variant often increased after 4 days. Minimal diversity shifts were noted in Microcystis-treated cultures, whilst those of Oscillatoria showed a greater diversity shift, indicating an increase in families containing isolates linked to bloom decline. Full article

Background: Perineural invasion (PNI) is a recognized pathway for cancer spread and is associated with poor outcomes in gastric cancer. However, the initial morphological characteristics of tumor–nerve interactions in early gastric cancer, particularly at the ultrastructural level, remain insufficiently defined. Case Presentation: We report a case of a 49-year-old man diagnosed with type IIc early gastric cancer. Histological examination revealed a combined poorly cohesive carcinoma (PCC)-NOS/signet-ring cell (SRC) histotype. Tumor invasion reached the middle third of the submucosa and was accompanied by a mature desmoplastic reaction, with metastases identified in two perigastric lymph nodes (pT1bN1M0). Transmission electron microscopy (TEM) revealed unmyelinated nerve fibers embedded within the submucosal desmoplastic stroma, in close proximity to infiltrating neoplastic cells. Several tumor cells exhibited cytoplasmic projections ranging from single extensions to multiple prominent pseudopods, resulting in an amoeboid morphology. Notably, an unmyelinated nerve process was observed within a cytoplasmic invagination of an individual tumor cell. Conclusions: Taken together, these ultrastructural findings provide novel and previously undescribed morphological evidence of a specific interaction between amoeboid tumor cells and peripheral unmyelinated nerve fibers within the submucosal desmoplastic stroma of early gastric cancer. The biological and clinical significance of this interaction in the early stages of perineural invasion warrants further investigation. Full article

In this study, in a culture of renal epithelial cells, we identified those expressing nestin, a cytoskeletal protein associated with stem/progenitor/activated/proliferating cell states. A mouse expressing GFP under the nestin promoter was used, followed by cell isolation and culture. It is hypothesized that this can be used to assess the stem/progenitor/activated/proliferating cell level in a mixed kidney cell culture. Both nestin-positive and nestin-negative cells were demonstrated to be present in the culture. After visualization, cells were attached to a glass slide with a grid, fixed, and prepared for electron microscopy analysis, with each cell visually identified by light microscopy being analyzed. Electron microscopy revealed tight interactions between nestin-positive and nestin-negative cells. Significant differences in the ultrastructure of nestin-positive and nestin-negative cells were observed. Nestin-positive cells were distinguished by a high ribosome content, indicating high protein-synthesizing activity. In the nestin–GFP-high (sorted) population examined by electron microscopy, vesicle-containing protrusions were frequently observed. These cells could contain multiple nuclei of varying sizes and had a high content of lysosomes. No significant differences in mitochondrial ultrastructure were observed in nestin-positive and -negative cells, although functional characteristics evaluated by the membrane potential probe differed. Full article

Orchids depend on mycorrhizal fungi for seed germination, a critical process especially for endangered species such as Cattleya purpurata. This study elucidates the ultrastructural ontogeny of the symbiosis between C. purpurata and the fungus Tulasnella sp. We demonstrate a defined spatiotemporal colonization pattern: hyphae penetrate exclusively via suspensor cells, migrate through the basal region of the embryo, and only then colonize the apical region. Upon colonization, the fungus triggers changes in the embryonic cells, including nuclear hypertrophy and peloton formation. Ultrastructural analysis revealed a sequence of fungal degradation, from intact hyphae to senescent hyphae containing myelin-like bodies and an electron-dense cytoplasm, suggesting that programmed senescence precedes peloton digestion. This supports the novel hypothesis of active fungal participation in modulating its own digestion, challenging classical models. Simultaneously, embryonic cells exhibited rapid metabolic conversion, with the transition from proplastids to amyloplasts, and then to chloroplasts in less than 20 days, marking the onset of autotrophy. This integrated morphological study not only expands fundamental knowledge about symbiotic development in orchids but also provides an optimized protocol for producing symbiotic seedlings, offering a direct tool for the reintroduction and conservation of this species. Full article

The Cambrian Period represents a critical yet debated interval in the global transition from “Aragonite Seas” to “Calcite Seas”. This study reconstructs the physicochemical evolution of paleoseawater through microstructural analysis and trace element geochemistry of Cambrian oolitic rocks in the northern Sichuan Basin, South China. Our results demonstrate that micrite envelopes on ooid margins and early submarine cements (Stage 1) effectively least-altered signals, resisting diagenetic alteration. Consequently, the maximum values of trace element in these fabrics serve as reliable proxies for paleoseawater reconstruction. Ooids from the upper Canglangpu Formation to the Longwangmiao Formation (Lower Cambrian, Series 2) are characterized by concentric laminations with tangential ultrastructures, high Sr contents (up to 1536 ppm), and high seawater molar Mg/Ca ratios (hereafter mMg/Ca, up to 5.02). These features contrast sharply with the radial fabrics, low Sr contents (<400 ppm), and low seawater mMg/Ca ratios (<0.4) observed in the Xixiangchi Formation (Upper Cambrian, Furongian). Integrating regional data with global correlations, this study confirms that Aragonite Sea conditions persisted on the northern margin of the Yangtze Block until at least the late Early Cambrian (Stage 4). The Middle Cambrian (Miaolingian) represents a pivotal transitional interval, leading to a complete shift to a stable Calcite Sea by the Late Cambrian (Furongian). These findings provide crucial regional constraints for refining the Phanerozoic model of seawater chemical evolution. Full article