Light Microscopy Techniques Research Articles

Morphological features of synaptic structures associated with amyloid plaques in the human cerebral cortex

BACKGROUND: Synapse damage and loss are fundamental to the pathogenesis of Alzheimer’s disease (AD) and lead to reduced cognitive function. Therefore, the study of synaptic abnormalities is crucial for understanding the pathogenesis and progression of AD. Synaptophysin, a transmembrane protein of synaptic vesicles, is most widely used as an immunohistochemical marker of synapses. AIM: to study the morphological features of synaptophysin–containing elements in the human cerebral cortex with amyloid plaques. METHODS: This study was made on the cerebral cortex samples of men and women aged 65 to 94 years (n = 10). Synapses and amyloid plaques were simultaneously detected with a new original light microscopy technique. This technique is based on immunohistochemical staining for synaptophysin and histochemical staining of amyloid plaques with Alcian blue. RESULTS: Abnormal synaptophysin-immunopositive structures presumed to be dystrophic presynapses were found within most of the identified amyloid plaques. These structures have large sizes and indistinct shapes and are present exclusively within amyloid plaques. Interestingly, corpora amylacea were also identified in all samples. They have spherical shapes and are located mainly in the perivascular, periventricular, and subpial regions of the brain. In all analyzed samples, synaptophysin-immunopositive terminals surrounding corpora amylacea had normal morphology and density and showed no signs of pathology. CONCLUSION: In this work, abnormal synaptophysin-containing structures associated with amyloid plaques were found in the human cerebral cortex using the original staining technique. Further study of these structures holds promise for identifying new biomarkers of synaptic disorganization, including in Alzheimer's disease.

Development and Validation of Particle Size Measurement for Mesalamine Nanocrystals Using Dynamic Light Scattering and Microscopic Techniques

Development and Validation of Particle Size Measurement for Mesalamine Nanocrystals Using Dynamic Light Scattering and Microscopic Techniques

Mycolichenological portrait of alder forest: alpha diversity revealed in 1ha plot in the Samursky National Park (Republic of Dagestan, Russia)

Aim. Xylobiont fungi and lichens determine the sustainability of forest ecosystems, but their species richness and taxonomic diversity depend on the forest type and the degree of its disturbance. Alder forests, characterised by a specific set of ecological conditions, represent poorly studied habitats in terms of myco‐ and lichenobiota. The aim of this work was to determine the species composition of aphyllophoroid fungi and epiphytic lichens on a 1 ha sample plot in a lowland floodplain forest dominated by Alnus glutinosa in the Delta Samura area of the Samursky National Park.The authors collected basidiomata of lignicolous fungi and lichen specimens on a sample plot of 1 ha during field studies. The surveyed forest area is represented by a community dominated by Alnus glutinosa and lianas. The material was identified using light microscopy techniques and a standard set of chemical reactions.Thirty‐three species of aphyllophoroid fungi (Basidiomycota) and 53 species of lichens and allied fungi (Ascomycota) were identified. Among them, 16 species (48 %) of aphyllophoroid fungi were recorded for the first time for the Samursky National Park, including six species revealed for the first time for the Republic of Dagestan, of which three species (Donkia pulcherrima, Phanerochaete cumulodentata and Sertulicium granuliferum) were new to the Northern Caucasus. Lichen species Arthothelium ruanum, Bacidia arceutina and Graphis pulverulenta are listed for the first time for the Republic of Dagestan. At the same time, 21 species of lichenized fungi were recorded for the first time on Alnus glutinosa within the region.The taxonomical structure of aphyllophoroid fungi revealed reflects the spring period of basidiomata‐based field study. The predominance of corticioid fungi and revealing hydnoid species among morphological groups may be indicative of the generally wetter habitats of alder forests in comparison to other forest types distributed in the studied area. Most of species were recorded on dead wood of Alnus glutinosa as the main forest‐forming tree. At the same time, each of other substrates (Carpinus betulus and Corylus avellana) turned out to be the habitat of species new to the region. The group of fungal species developing on large‐scale substrate units, represented by fallen trunks, was the most prevalent and is to be considered as more vulnarable in a case of anthropogenical habitat disturbance. The majority of epiphytic lichens discovered on alder are not specific to this woody substrate, except for single findings. These species belong to epiphytes inhabiting the Samur forest, the core of the lichenobiota of which is composed of thermophilous lichens of lowland deciduous forests. In our opinion, the relict character of the forest, which is an isolated and rather small forest massif with relatively homogeneous climatic conditions, causes a high similarity between the species composition of lichens revealed in the surveyed sample plot with Alnus glutinosa and previously studied plots dominated by Carpinus betulus, Populus alba, and Quercus robur.

Localization of albumin with correlative super resolution light- and electron microscopy in the kidney

The functioning of vertebrate life relies on renal filtration of surplus fluid and elimination of low-molecular-weight waste products, while keeping serum proteins in the blood. In disease, however, there is leak of serum proteins and tracing them to identify the leaking position within tissue with a nanometer resolution poses a significant challenge. Correlative microscopy integrates the specificity of fluorescent protein labeling into high-resolution electron micrographs. Using chemical tagging of albumin with synthetic fluorophores we achieve protein-specific labeling that preserve their post-embedding fluorescence after high-pressure freezing and freeze-substitution of murine kidney tissue. Using advanced registration techniques for super-resolution correlative light and electron microscopy, we can localize the labeled albumin with a high precision in the x-y plane of electron micrographs and cartograph its distribution. Thereby we can quantify the albumin concentration and measure a linear reduction gradient across the kidney filtration barrier. Our study shows the feasibility of combining different microscopy contrasts for tracing fluorescently labeled protein markers with super resolution in various tissue samples and opens new perspectives for correlative imaging in volume electron microscopy.

Use of a Single-Fiber Optical Probe for the Detection of Tumor Fluorescence in High-Grade Glioma.

High-grade glioma (HGG) is the most common primary brain tumor in adults. The overall median survival is between 14 and 16 months. Fluorescence-guided surgery by detection of protoporphyrin IX (PpIX) fluorescence has been shown to improve the extent of resection, translating to improved progression-free survival. Microscope-based fluorescence detection techniques are associated with several pain points, some of which may be addressed by using contact-based spectroscopy. We aimed to investigate the accuracy of an optical fiber at detecting PpIX fluorescence by performing real-time spectroscopy in patients with HGG. Adult patients undergoing fluorescence-guided surgery for suspected HGG were recruited prospectively. Intraoperatively, samples from cortex, white matter, and tumor were taken. These samples were interrogated using standard white and blue light microscope techniques and the optical fiber. These specimens were then assessed by neuropathology to determine whether the tumor tissue was present within them. We collected 89 samples from 28 patients. There was an equal ratio of men to women, with a median age of 66.5 years. The accuracy of the probe for detecting PpIX fluorescence was 75.9%, compared with 56.6% for the operating microscope, with a significant improvement in sensitivity (χ2 = 11.84, P < .001). The optical fiber probe was more accurate than the operating microscope for detecting PpIX fluorescence. This technology has potential value in improving the accuracy of fluorescence-guided surgery and has potential practical benefits relating to surgical workflow.

Light Microscopic and Scanning Electron Microscopic Techniques to Characterize Nutlets of Some Indian Cyperoideae (Cyperaceae) and Their Taxonomic Significance.

In the present investigation, nutlet morphological and micro-morphological characters were analyzed using Light Microscope (LM) and Scanning Electron Microscope (SEM) in 38 taxa under 13 genera from the sub-family Cyperoideae of Cyperaceae to find out whether these characters are taxonomically important or not. Nutlet morphology and surface characters of the representative taxa from all the possible tribes under the sub-family Cyperoideae namely, Fuireneae, Cypereae, Cariceae, Abildgaardieae, Eleocharideae, Pseudoschoeneae, Schoenoplecteae, and Sclerieae were evaluated for their taxonomic significance. Cluster analysis was employed considering nutlet morphological characters to determine the overall similarity among the taxa based on 153 character states. Except in few specified cases, grouping of the taxa in the clusters is in accordance to the taxonomic treatments made by recent Cyperologists. Nutlets in the tribe Abildgaardieae showed maximum level of variability in size, shape, and surface ornamentation at the level of higher taxon, but showed specificity at the species level. Tuberculate, striate-reticulate, and transversely wavy ridged surface ornamentations were found in different species of Fimbristylis. Previously described cryptic variation, and effect of different ploidy level were not reflected in nutlet surface morphology and micromorphology in Fimbristylis dichotoma and F. ovata complexes which was previously made the taxa taxonomically very difficult. Serrulate anticlinal wall in F. bisumbellata was the most unique in Fimbristylis. Species under the megadiverse genus Carex representing the tribe Cariceae showed very unique type of surface ornamentation. Surface walls of all the studied species of Carex were characterized by polygonal epidermal cells with single conical silica body (2-3 per cell in C. speciosa) of variable length and sizes. Most interestingly, in C. nubigena, presence of the central silica body and peripheral satellites was not consistent. Based on the presence and absence, two different variants under the species were identified. In C. nubigena, when silica body was present, epidermal cells were characterized by central conical silica body surrounded by variable number of satellites. The present investigation first time reports this novel nutlet surface character in C. nubigena. Among the studied characters, length and height of conical, height of apex, and width of apex are variable among Carex species. On the other hand, exclusion of the genera Schoenoplectiella and Schoenoplectus from tribe Scirpeae s.l. and placement under the tribes Pseudoschoeneae and Schoenoplecteae (respectively) was also supported by the present investigation. The present study also confirms that nutlet morphological and micro-morphological characters are useful in identification and arrangement of different taxa under the subfamily Cyperoideae of Cyperaceae. Result of the present investigation was correlated and discussed in comparative manner with the treatments of the recent past.

Amoebicidal activity of essential oils and essential oil-based microemulsions of Aloysia citrodora Ortega ex Pers., Cymbopogon winterianus Jowitt ex Bor, and Ocimum gratissimum L. against Acanthamoeba polyphaga trophozoites.

Evaluate the in vitro efficacy of the essential oils derived from Aloysia citrodora (Verbenaceae), Cymbopogon winterianus (Poaceae), and Ocimum gratissimum (Lamiaceae) against Acanthamoeba polyphaga trophozoites. Additionally, microemulsions formulated with these essential oils, along with their major components, were analyzed. The prepared microemulsions were characterized using polarized light microscopy and rheological techniques. The amoebicidal activity was determined by measuring the inhibitory concentration (IC50). Flow cytometry was employed to detect membrane damage and alterations in trophozoites size. The results revealed transparent and thermodynamically stable microemulsions. The essential oil from O. gratissimum exhibited a lower IC50, with values of 280.66 and 47.28µg ml-1 after 24 and 48 h, respectively. When microemulsions containing essential oils were tested, the IC50 values exhibited a reduction of over 80% after 24 h. Particularly, eugenol, a constituent of the O. gratissimum essential oil, displayed higher amoebicidal activity. The essential oils also caused damage to the cell membrane, resulting in the subsequent death of the trophozoites. The EOs of A. citrodora, C. winterianus, and O. gratissimum and their microemulsions showed antiparasitic effect against A. polyphaga trophozoites, representing promising alternatives for the treatment of diseases caused by this protozoan.

Genome-wide analysis of the biophysical properties of chromatin and nuclear proteins in living cells with Hi-D.

To understand the dynamic nature of the genome, the localization and rearrangement of DNA and DNA-binding proteins must be analyzed across the entire nucleus of single living cells. Recently, we developed a computational light microscopy technique, called high-resolution diffusion (Hi-D) mapping, which can accurately detect, classify and map diffusion dynamics and biophysical parameters such as the diffusion constant, the anomalous exponent, drift velocity and model physical diffusion from the data at a high spatial resolution across the genome in living cells. Hi-D combines dense optical flow to detect and track local chromatin and nuclear protein motion genome-wide and Bayesian inference to characterize this local movement at nanoscale resolution. Here we present the Python implementation of Hi-D, with an option for parallelizing the calculations to run on multicore central processing units (CPUs). The functionality of Hi-D is presented to the users via user-friendly documented Python notebooks. Hi-D reduces the analysis time to less than 1 h using a multicore CPU with a single compute node. We also present different applications of Hi-D for live-imaging of DNA, histone H2B and RNA polymerase II sequences acquired with spinning disk confocal and super-resolution structured illumination microscopy.

Histological Fixation Process and Fixatives

Tissue monitoring generally includes the stages of fixation, dehydration, clearing, hardening (infiltration), paraffin blocking/paraffin(emmeding), sectioning, water removal, routine staining, and mounting. Fixation is the basic and first step in the microscopic examination of tissues. The histotechnical process, which includes components such as detection, tissue tracking and staining, basically aims to capture and visualize the state of the relationships between tissue parts inside and outside the cell and various cells at a certain time as close as possible to the living state. Maintaining the natural structure of the tissue is important for the follow-up phase. The main feature of a good fixative should protect the sample and make the macromolecules insoluble without changing the chemistry of the sample studied and allowing it to be examined as closely as possible to its living state. In histological tissue analysis including light microscope and electron microscope techniques, an appropriate fixation method is selected for each study. Detection solutions are classified in terms of content. The most commonly used fixative in light microscopic follow-up procedures is 10% formaldehyde. For the electron microscope, the gluteraldehyde-osmium tetraoxide binary is widely used for fixation purposes. Gluteraldehyde acts more slowly and is more expensive than formaldehyde. Formalin is obtained by dissolving formaldehyde in water. In addition, the fixed samples can be stored in the solution for months. With a successful fixation process, the structural properties of the tissue are preserved and thus it is possible to examine the tissue as closely as possible. Thus, better quality sections are obtained from the tissue samples taken. For this reason, it will be more efficient to interpret well-fixed samples by photographing them. In this review, which was created by using various sources, the elements to be considered for an ideal fixation were determined and it was aimed to provide an overview of successful fixation for light microscope and electron microscope.

Unique root hydraulic and mechanical properties support the resilience of grapevines adapted to the Atacama Desert.

Cortical lacunae caused by drought, especially observed in hybrids originating from Vitis rupestris, disrupt the connection between roots and soil. Yet, the physiological processes behind lacuna formation during drought and its consistency across Vitis species remain unclear. Here, we used a root pressure probe to investigate fine root hydraulic and mechanical properties, in the arid-adapted R-65 and drought-susceptible 101-14Mgt cultivars. We then performed P-V curves, root sap osmolality, and electrolyte leakage (EL) and used fluorescent light microscopy techniques. Only 101-14Mgt showed lacunae formation during drought due to its stiffer cortical tissue, unlike R-65. Lacunae resulted in a notable decline in root hydraulic conductivity during severe drought, with increased EL and root sap osmolality, indicating potential cellular damage. R-65 displayed different and xerophyte-like characteristics featuring a higher turgor loss point and decreased root capacitance, essential for maintaining root structural integrity in arid conditions. Our findings highlight lacuna formation is impacted by root tissue elasticity possibly linked to specific Vitis species favoring deeper rooting. In arid-adapted grapevines, hydraulic regulators such as reduced turgor loss point, and root capacitance could contribute to enhanced drought tolerance.

Morpho-anatomical studies of family lamiaceae species of district Lahore, Punjab: a revision to flora of Pakistan

BackgroundThis study was aimed to determine the taxonomic position and delimitation of fifteen Lamiaceae taxa using leaf epidermal morpho-anatomical features in Lahore. A main objective of the study was also the revision and upgradation of Lamiaceae taxa in the flora of Pakistan, as no details of studied species are found in the flora of Pakistan.MethodsThe examination of significant anatomical parameters, such as epidermal cell shape and size, stomatal types, guard and subsidiary cells shape and size, stomatal cavity size, trichome size and shape, oil droplets, crystals, and secretory cavity characteristics were studied using light microscopic (LM) and scanning electron microscopic (SEM) techniques. Among all the studied Lamiaceae species, these anatomical features varied significantly. Principal component analysis and correlation were done to distinguish the species’ similarities.ResultsMost species had pentagonal and hexagonal epidermal cells with straight anticlinal wall thickness. On the adaxial surface, paracytic stomata were found in Ocimum basilicum L. and Rosmarinus officinalis L. Diacytic stomata was observed in Ajuga reptans L. and anisocytic stomata in Galeopsis tetrahit L. In the abaxial surface, trichomes were present in five species, i.e., Mentha suaveolens Ehrh. A. reptans, Thymus vulgaris L., M. haplocalyx, and Salvia splendens Ewat. In S. splendens, peltate and glandular trichomes were seen whereas, in other species, trichomes were long, unbranched glandular and had tapering ends. In adaxial side trichomes were present only in M. suaveolens, A. reptans, S. bazyntina, O. basciculum, S. splendens, S. officinalis, S. rosemarinus. In other species, trichomes were absent on the adaxial surface. In abaxial view, M. suaveolens had the largest length of trichomes, and O. basciculum had the smallest. S. splendens L. had the largest trichome width, while T. vulgaris had the smallest.ConclusionHence, according to these findings, morpho-anatomical traits are useful for identifying Lamiaceae taxa. Also, there is a need of upgradation and addition of studied taxa in flora of Pakistan comprehensively.

Stereoscopic Microscopy of Snow Crystals

Abstract Snow crystals (snowflakes) are composed of an enormous diversity of shapes that have attracted significant scientific attention over the past decades. Under the microscope, these natural structures are frequently characterized by high complexity, the detailed exploration of which requires the use of enhanced magnifications. In the work presented here, an insight into the microcosm of snow crystals is presented by application of specific light microscopy techniques. Micrographs were produced by means of a low-temperature (LT) device that prevented premature melting of the structures. Additionally, single crystals were imaged as to a stereoscopic visualization allowing the detailed spatial investigation of specific structural elements.

A microscopical and ultrastructural analysis of the embryonic epidermis of the pool frog, Pelophylax lessonae (Camerano, 1882) (Anura: Ranidae)

We analysed the embryonic epidermis of the pool frog, Pelophylax lessonae, by light and electron microscopy techniques, and characterized preliminarily its mucous secretions with conventional histochemistry (Toluidine Blue, Periodic Acid-Schiff, Alcian blue pH 2.5 and Alcian blue pH 1.0). At Gosner’s developmental stage 21, the epidermis consisted of a bilayered epithelium with five cell types. Basal cells (BCs) constituted the basal layer, presented a large nucleus and were sometimes observed in mitosis. Ciliated cells (CCs) had a ciliated apical membrane, with carboxylated glycans in the sub-apical portion. TEM analysis revealed small vesicles just below the surface, a central nucleus, and evident yolk plates. Goblet cells (GCs) and small secretory cells (SSCs) showed secreting vesicles and vacuoles, respectively. In the mucus secretion of GCs sialosulphomucins appeared, while in that of SSCs sulphation was not observed. Under TEM, GCs had irregular shaped nuclei and a less electron-dense cytoplasm with respect to SSCs. Ionocytes (INs) presented apical microvilli and a high electron-dense cytoplasm with vacuoles. SEM analysis revealed that GCs outnumbered the other cell types and that SSCs and INs were usually located together near to GCs. The relatively simple structure of the epidermis and its direct interfacing with the environment renders it a good model for the study of structure and development of mucociliary epithelia, as well as of its alterations in the presence of toxicants.

Zinc-alkaline phosphatase at sites of aortic calcification

Zinc (Zn) is a normal trace element in mineralizing tissues, but it is unclear whether it is primarily bound to the mineral phase or to organic molecules involved in the mineralization process, or both. Tissue-nonspecific alkaline phosphatase (TNAP) is a Zn metalloenzyme with two Zn ions bound to the M1 and M2 catalytic sites that functions to control the phosphate/pyrophosphate ratio during biomineralization. Here, we studied aortas from Tagln-Cre +/−; HprtALP/Y TNAP overexpressor (TNAP-OE) mice that develop severe calcification. Zn histochemistry was performed using the sulfide-silver staining method in combination with a Zn partial extraction procedure to localize mineral-bound (mineral Zn) and TNAP-bound Zn (tenacious Zn), since soluble Zn (loose Zn) is extracted during fixation of the specimens. Two synthetic bone mineral composites with different Zn content, bone ash, and rat epiphyseal growth plate cartilage were used as controls for Zn staining. In order to correlate the distribution of mineral and tenacious Zn with the presence of mineral deposits, the aortas were examined histologically in unstained and stained thin sections using various light microscopy techniques. Our results show that 14 and 30 dpn, TNAP is concentrated in the calcifying matrix and loses Zn as Ca2+ progressively displaces Zn2+ at the M1 and M2 metal sites. Thus, in addition to its catalytic role TNAP has an additional function at calcifying sites as a Ca-binding protein.Graphical

A morphological analysis of calcium hydroxylapatite and poly-l-lactic acid biostimulator particles.

Injectable fillers, pivotal in aesthetic medicine, have evolved significantly with recent trends favoring biostimulators like calcium hydroxylapatite (CaHA-CMC; Radiesse, Merz Aesthetics, Raleigh, NC) and poly-l-lactic acid (PLLA; Sculptra Aesthetics, Galderma, Dallas, TX). This study aims to compare the particle morphology of these two injectables and examine its potential clinical implications. Utilizing advanced light and scanning electron microscopy techniques, the physical characteristics of CaHA-CMC and PLLA particles were analyzed, including shape, size, circularity, roundness, aspect ratio, and quantity of phagocytosable particles. The findings reveal several morphological contrasts: CaHA-CMC particles exhibited a smooth, homogenous, spherical morphology with diameters predominantly ranging between 20 and 45µm, while PLLA particles varied considerably in shape and size, appearing as micro flakes ranging from 2 to 150µm in major axis length. The circularity and roundness of CaHA-CMC particles were significantly higher compared to PLLA, indicating a more uniform shape. Aspect ratio analysis further underscored these differences, with CaHA-CMC particles showing a closer resemblance to circles, unlike the more oblong PLLA particles. Quantification of the phagocytosable content of both injectables revealed a higher percentage of phagocytosable particles in PLLA. These morphological distinctions may influence the tissue response to each treatment. CaHA-CMC's uniform, spherical particles may result in reduced inflammatory cell recruitment, whereas PLLA's heterogeneous particle morphology may evoke a more pronounced inflammatory response.

Asbestos: detection and characterization in tissue

When asbestos fibers are inhaled, asbestos bodies can form in the lungs with the involvement of macrophages. It can take decades from the last exposure to the onset of an asbestos-related disease. The aim of this review is to present methods to detect asbestos bodies in lung tissue, the development of diagnostic criteria and to discuss pros and cons of different methods. Observations and evaluations from the German Mesothelioma Register, along with relevant literature review and expert recommendations in guidelines are presented. Assessing asbestos-related diseases requires recognition of the person's occupational history, the asbestos fiber burden in the lungs, and determining fiber types. Various methods have been developed and validated, including light microscopy techniques such as bright-field microscopy, phase-contrast microscopy, polarization microscopy, and differential interference microscopy, as well as electron microscopy techniques like field-emission-scanning electron microscopy (e.g., FE-SEM) and transmission electron microscopy (TEM). The use of asbestos has been heavily restricted worldwide, even completely banned in Europe. Thus, patients' exposure to asbestos is decreasing. However, asbestos exposure during renovations, demolitions, or through unconscious handling of asbestos-containing materials remains aconcern.

Continuous endosomes form functional subdomains and orchestrate rapid membrane trafficking in trypanosomes

Endocytosis is a common process observed in most eukaryotic cells, although its complexity varies among different organisms. In Trypanosoma brucei, the endocytic machinery is under special selective pressure because rapid membrane recycling is essential for immune evasion. This unicellular parasite effectively removes host antibodies from its cell surface through hydrodynamic drag and fast endocytic internalization. The entire process of membrane recycling occurs exclusively through the flagellar pocket, an extracellular organelle situated at the posterior pole of the spindle-shaped cell. The high-speed dynamics of membrane flux in trypanosomes do not seem compatible with the conventional concept of distinct compartments for early endosomes (EE), late endosomes (LE), and recycling endosomes (RE). To investigate the underlying structural basis for the remarkably fast membrane traffic in trypanosomes, we employed advanced techniques in light and electron microscopy to examine the three-dimensional architecture of the endosomal system. Our findings reveal that the endosomal system in trypanosomes exhibits a remarkably intricate structure. Instead of being compartmentalized, it constitutes a continuous membrane system, with specific functions of the endosome segregated into membrane subdomains enriched with classical markers for EE, LE, and RE. These membrane subdomains can partly overlap or are interspersed with areas that are negative for endosomal markers. This continuous endosome allows fast membrane flux by facilitated diffusion that is not slowed by multiple fission and fusion events.

Continuous endosomes form functional subdomains and orchestrate rapid membrane trafficking in trypanosomes.

Endocytosis is a common process observed in most eukaryotic cells, although its complexity varies among different organisms. In Trypanosoma brucei, the endocytic machinery is under special selective pressure because rapid membrane recycling is essential for immune evasion. This unicellular parasite effectively removes host antibodies from its cell surface through hydrodynamic drag and fast endocytic internalization. The entire process of membrane recycling occurs exclusively through the flagellar pocket, an extracellular organelle situated at the posterior pole of the spindle-shaped cell. The high-speed dynamics of membrane flux in trypanosomes do not seem compatible with the conventional concept of distinct compartments for early endosomes (EE), late endosomes (LE), and recycling endosomes (RE). To investigate the underlying structural basis for the remarkably fast membrane traffic in trypanosomes, we employed advanced techniques in light and electron microscopy to examine the three-dimensional architecture of the endosomal system. Our findings reveal that the endosomal system in trypanosomes exhibits a remarkably intricate structure. Instead of being compartmentalized, it constitutes a continuous membrane system, with specific functions of the endosome segregated into membrane subdomains enriched with classical markers for EE, LE, and RE. These membrane subdomains can partly overlap or are interspersed with areas that are negative for endosomal markers. This continuous endosome allows fast membrane flux by facilitated diffusion that is not slowed by multiple fission and fusion events.

A Quantitative Assessment of Apoptotic Index with Varying Histological Degree of Dysplasia and Squamous Cell Carcinoma of Oral Cavity - A Light Microscopic Study.

The aim of the present study was to quantitatively assess the apoptotic index at a light microscopic level in hyperkeratosis with varying histological degrees of dysplasia and different grades of oral squamous cell carcinoma (OSCC) and its correlation with prognostic significance. The study included the histo-pathologically diagnosed cases of hyperkeratosis with varying degrees of dysplasia and different grades of OSCC, which were retrieved from the archives of the department, and clinical details were retrieved from the case records of the patients. The sample size consisted of 80 biopsied cases, divided into seven groups of 10 experimental cases and one group of 10 cases of normal mucosa as a control group. The age range of 50-59 shows maximum patients of hyperkeratosis with varying degrees of dysplasia and OSCC. Maximum apoptotic bodies were seen in cases of severe dysplasia and well-differentiated cases of OSCC. There was an observational difference noticed in apoptotic bodies between the patients who had less than 1-year disease-free survival rate. The apoptotic cells are being seen using routine light microscopy techniques with hematoxylin and eosin staining. In different grades of squamous cell carcinoma, a decrease in the apoptotic count was noticed from well-differentiated squamous cell carcinoma toward poorly differentiated squamous cell carcinoma cases. Increased mean apoptotic bodies were observed in patients showing less than 1 year of survival.

Cell proliferation and regeneration in the gill.

Seminal studies from the early 20th century defined the structural changes associated with development and regeneration of the gills in goldfish at the gross morphological and cellular levels using standard techniques of light and electron microscopy. More recently, investigations using cell lineage tracing, molecular biology, immunohistochemistry and single-cell RNA-sequencing have pushed the field forward and have begun to reveal the cellular and molecular processes that orchestrate cell proliferation and regeneration in the gills. The gill is a multifunctional organ that mediates an array of important physiological functions, including respiration, ion regulation and excretion of waste products. It is comprised of unique cell types, such as pavement cells, ionocytes, chemoreceptors and undifferentiated stem or progenitor cells that regulate growth and replenish cell populations. The gills develop from the embryonic endoderm and are rich in cell types derived from the neural crest. The gills have the capacity to remodel themselves in response to environmental change, such as in the case of ionocytes, chemoreceptors and the interlamellar cell mass, and can completely regenerate gill filaments and lamellae. Both processes of remodeling and regeneration invariably involve cell proliferation. Although gill regeneration has been reported in only a limited number of fish species, the process appears to have many similarities to regeneration of other organs in fish and amphibians. The present article reviews the studies that have described gill development and growth, and that demonstrate a suite of genes, transcription factors and other proteins involved in cell proliferation and regeneration in the gills.