Showing papers on "Ultrastructure published in 2005"
TL;DR: Electron microscopical results revealed that BLC are rich in mitochondria, Golgi stacks, and Golgi-derived vesicles, suggesting that these cells are actively engaged in secretion of materials to their cell walls, and alteration of AGPs significantly inhibits the attachment of the bacteria to the surface of BLC and root tip.
Abstract: Plant roots of many species produce thousands of cells that are released daily into the rhizosphere. These cells are commonly termed border cells because of their major role in constituting a biotic boundary layer between the root surface and the soil. In this study, we investigated the occurrence and ultrastructure of such cells in Arabidopsis (Arabidopsis thaliana) using light and electron microscopy coupled to high-pressure freezing. The secretion of cell wall molecules including pectic polysaccharides and arabinogalactan-proteins (AGPs) was examined also using immunofluorescence microscopy and a set of anticarbohydrate antibodies. We show that root tips of Arabidopsis seedlings released cell layers in an organized pattern that differs from the rather randomly dispersed release observed in other plant species studied to date. Therefore, we termed such cells border-like cells (BLC). Electron microscopical results revealed that BLC are rich in mitochondria, Golgi stacks, and Golgi-derived vesicles, suggesting that these cells are actively engaged in secretion of materials to their cell walls. Immunocytochemical data demonstrated that pectins as well as AGPs are among secreted material as revealed by the high level of expression of AGP-epitopes. In particular, the JIM13-AGP epitope was found exclusively associated with BLC and peripheral cells in the root cap region. In addition, we investigated the function of BLC and root cap cell AGPs in the interaction with rhizobacteria using AGP-disrupting agents and a strain of Rhizobium sp. expressing a green fluorescent protein. Our findings demonstrate that alteration of AGPs significantly inhibits the attachment of the bacteria to the surface of BLC and root tip.
152 citations
TL;DR: Thylakoids were heavily swollen, some portions of the mitochondria and endoplasmic reticulum were structurally altered, and the plasmalemma had pulled away from the cell wall in places, but no ultrastructural changes in cell organelles occurred at doses of 0 to 5 Gy.
Abstract: We examined ultrastructural changes of the cell organelles ofArabidopsis stems in response to gamma irradiation. Seedlings treated with 0 to 5 Gy developed normally, while height growth in plants exposed to 50 Gy was significantly inhibited. Based on TEM observations, the chloroplasts were extremely sensitive to such irradiation. In particular, the thylakoids were heavily swollen, some portions of the mitochondria and endoplasmic reticulum were structurally altered, and the plasmalemma had pulled away from the cell wall in places. However, no ultrastructural changes in cell organelles occurred at doses of 0 to 5 Gy.
135 citations
TL;DR: Most regions of tumor vessels that lack CD31 and CD105 immunoreactivity represent attenuated endothelial cells with abnormal expression of endothelial cell markers, but some are gaps between endothelialieri, and the integrity of the basement membrane in these regions is compromised.
Abstract: Endothelial cells of blood vessels in tumors may be thin, fragile, and defective in barrier function. We found previously that the endothelium of vessels in human colon carcinoma xenografts in mice is a mosaic structure. Approximately 85% of tumor vessels have uniform CD31 and/or CD105 immunoreactivity, but the remainder have focal regions that lack these common endothelial markers. The present study assessed the ultrastructure of the vessel lining and the integrity of the basement membrane in these regions. Using immunolabeling and confocal microscopy, we identified blood vessels that lacked CD31 and CD105 immunoreactivity and then analyzed the ultrastructure of these vessels by transmission electron microscopy. Eleven percent of vessels in orthotopic tumors and 24% of vessels in ectopic tumors had defects in CD31 and CD105 staining measuring on average 10.8 μm (range, 1-41.2 μm). Ultrastructural studies identified endothelial cells at 92% of CD31- and CD105-negative sites in orthotopic tumors and 70% of the sites in ectopic tumors. Thus, most regions of tumor vessels that lack CD31 and CD105 immunoreactivity represent attenuated endothelial cells with abnormal expression of endothelial cell markers, but some are gaps between endothelial cells. More than 80% of the defects lacked immunoreactivity for multiple basement membrane proteins.
117 citations
TL;DR: It is indicated that low concentrations of HgCl2 induce apoptosis by inhibiting mitochondrial function, and the OK cell line may be considered a useful tool for the study of programmed cell death involving mercurial species and other heavy metals.
54 citations
TL;DR: Observations indicated that the primary wall is formed by the deposition of two distinct layers during the elongation of the internode and that secondary wall synthesis may begin before the complete cessation ofinternode and fibre elongation.
50 citations
TL;DR: The antennal glands of the adult lobster possess active ion exchanges capabilities and present morphological and enzymatic features of ionocytes, which are well documented in crustacean freshwater species.
Abstract: Unlike in crustacean freshwater species, the structure and ultrastructure of the excretory antennal gland is poorly documented in marine species. The general organization and ultrastructure of the ...
49 citations
TL;DR: The effects of glyphosate on protein metabolism, mesophyll cell ultrast structure and nodule ultrastructure and functioning of Lupinus albus cv.
47 citations
TL;DR: An electron microscope has been used to investigate the ultrastructure of leaf cells in Deschampsia antarctica Desv.
Abstract: An electron microscope has been used to investigate the ultrastructure of leaf cells in Deschampsia antarctica Desv. (Poaceae). The leaf anatomy exhibits features typical of xerophytes. New ultrastructural features were found in mesophyll cells. Chloroplasts in mesophyll cells of D. antarctica leaves form small vesicles and pockets. The outer chloroplast membrane forms vesicles, and pockets are invaginations of both membranes. The invaginations contain small vesicles, mitochondria, or lipid droplets. The mitochondria or peroxisomes adhere very tightly to the chloroplasts.
45 citations
TL;DR: Comparative analysis of deposit morphology and the differentiation of the sternal epithelia provide information on the evolution of CaCO(3) deposit formation in relation to the degree of adaptation to terrestrial environments.
44 citations
TL;DR: The aim of the present study was to characterize the ultrastructure of zebu cow preantral follicles, and some unique characteristics could be observed as compared with what has been reported for follicles of Bos taurus cattle.
40 citations
TL;DR: To evaluate changes in hepatocyte ultrastructure within the hepatic acinus during the liver regenerative process, light and electron microscopy observations on specimens taken 0 h, 24 h and 96 h after partial hepatectomy investigated the hepatocyte structure and ultrast structure in the periportal and pericentral area of the hepatics acinus, with a particular emphasis on mitochondria ultrast Structure.
TL;DR: The state of the art of cardiac tissue engineering is discussed, in light of the biomimetic approach that reproduces in vitro some of the conditions present during normal tissue development.
Abstract: We hypothesized that clinically sized (1-5 mm thick),compact cardiac constructs containing physiologically high density of viable cells (10 8 cells/cm 3 ) can be engineered in vitro by using biomimetic culture systems capable of providing oxygen transport and electrical stimulation, designed to mimic those in native heart. This hypothesis was tested by culturing rat heart cells on polymer scaffolds, either with perfusion of culture medium (physiologic interstitial velocity, supplementation of perfluorocarbons), or with electrical stimulation (continuous application of biphasic pulses, 2 ms, 5 V, 1 Hz). Tissue constructs cultured without perfusion or electrical stimulation served as controls. Medium perfusion and addition of perfluorocarbons resulted in compact, thick constructs containing physiologic density of viable, electromechanically coupled cells, in contrast to control constructs which had only a 100 μm thick peripheral region with functionally connected cells. Electrical stimulation of cultured constructs resulted in markedly improved contractile properties, increased amounts of cardiac proteins, and remarkably well developed ultrastructure (similar to that of native heart) as compared to non-stimulated controls. We discuss here the state of the art of cardiac tissue engineering, in light of the biomimetic approach that reproduces in vitro some of the conditions present during normal tissue development.
Journal Article•
TL;DR: The ultrastructure of the cells prepared by freeze-substitution compared favorably with that seen in cells subjected to conventional chemical fixation.
Abstract: In Platanthera chlorantha, nectar is secreted into the lumen of the nectary spur by numerous unicellular hairs. These hairs arise from epidermal cells lining the spur. The nectary was studied in the presecretory (closed bud, 4 days before anthesis), secretory (day 2 of anthesis) and resorption (days 14–16 of anthesis) stages to compare the ultrastructure of the cells during various stages of nectary activity. Plant tissue was fixed for conventional TEM or prepared by freeze-substitution. Secretory cell ultrastructure was observed to change significantly during the various stages of nectary activity. During the presecretory stage, the cells have a large nucleus, dense, granular cytoplasm with numerous mitochondria and ER, and several small vacuoles. Plastids within secretory epidermal cells or subepidermal parenchyma enclose starch, but starch is absent throughout nectar secretion and resorption. During the secretory stage, plastids with a dense stroma contain tubules enclosing osmiophilic material. Abundant dictyosomes and secretory vesicles occur in the cytoplasm, particularly near the plasmalemma, indicating that granulocrine secretion operates in this species. During the resorption stage, most cells still have dense cytoplasm with numerous mitochondria and ER, but dictyosomes are uncommon. Vesicles are present adjacent to the cell wall; they are similar in size and occur in similar numbers to those seen during the secretory stage. They are probably formed by endocytosis. The ultrastructure of the cells prepared by freeze-substitution compared favorably with that seen in cells subjected to conventional chemical fixation.
TL;DR: The rabbit has a CALT with typical follicular morphology, including HEV for regulated lymphocyte migration and epithelial cells with ultrastructural characteristics of M‐cells that allow antigen transport as indicated by the GC‐reaction.
Abstract: Conjunctiva-associated lymphoid tissue (CALT) is a part of the eye-associated lymphoid tissue (EALT) at the ocular surface. Its lymphoid follicles are usually characterized by using light microscopy, but its ultrastructure remains largely unknown. In this study, flat whole-mount conjunctival tissues (n = 42) from 21 young adult rabbits were investigated native in reflected light, and further stained and cleared (n = 6), in paraffin histology sections (n = 6), scanning electron microscopy (SEM, n = 4) and transmission electron microscopy (TEM, n = 4). Secondary lymphoid follicles accumulated into a dense group nasally towards the lacrimal punctum of the lower lid. High endothelial venules (HEV) with typical ultrastructure occurred in the parafollicular zone. The bright germinal centre (GC) contained lymphoblasts, follicular dendritic cells, apoptotic cells and tingible body macrophages. The follicle-associated epithelium (FAE) was devoid of goblet cells and contained groups of lymphoid cells. TEM showed these cells to be located in cytoplasmic pockets of superficial electron-lucent cells with a thin cytoplasmic luminal lining that contained a fine filament meshwork and numerous endocytotic vesicles. These M-cells were sitting between and on top of the ordinary dense epithelial cells that were located basally and formed pillar-like structures. In stereoscopic SEM, the surface cells were very large, had a polygonal outline and covered cavernous spaces. The rabbit has a CALT with typical follicular morphology, including HEV for regulated lymphocyte migration and epithelial cells with ultrastructural characteristics of M-cells that allow antigen transport as indicated by the GC-reaction. The arrangement of these M-cells on top of and between epithelial pillar cells may reflect a special structural requirement of the multilayered CALT FAE.
TL;DR: The ultrastructure suggests that F-cells synthesize proteins, R-cells storage nutrients and B-cells have a secretory or excretory function, and confirms the independent origin of F, B and R cells from the embryonic cells.
Abstract: The aim of this study is to describe the ultrastructure of the hepatopancreas of P. argentinus in intermoult. P. argentinus hepatopancreas was studied using standard TEM techniques. Each tubule consists of four cellular types: E (embryonic), F (fibrillar), R (resorptive) and B (blister like). E-cells have embryonic features and some of them were found in mitosis. F, R and B cells possess an apical brush border. F-cells have a central or basal nucleus, a conspicuous RER, and dilated Golgi cisternae. R cells show a polar organization of organelles in three areas: apical, with numerous mitochondria and sER tubules, a central area with the nucleus and RER, and a basal area containing a sER-like tubule system and mitochondria. B-cells were observed at different stages of their life cycle. In an early differentiation stage they comprise an apical endocytotic complex and Golgi vesicles. The fusion of endocytotic and Golgi vesicles originates subapical vacuoles. During maturation, a big central vacuole is formed by coalescence of subapical vacuoles. The central vacuole is eliminated by holocrine secretion. The ultrastructure suggests that F-cells synthesize proteins, R-cells storage nutrients and B-cells have a secretory or excretory function, and confirms the independent origin of F, B and R cells from the embryonic cells.
TL;DR: Ultrastructure of sperm from tetraploids was compositionally similar to diploids except for overall size and the number of mitochondria, and the ratios of the sperm head length to head width, and sperm headlength to flagellum length were the same for both ploidy levels for fixed and live samples.
TL;DR: The cleavage, development and ultrastructure of larvae and settlers in the oviparous sponge Chondrilla australiensis are investigated, and the monophyly of order Chondrosida is confirmed.
Abstract: Summary This study investigated the cleavage, development and ultrastructure of larvae and settlers in the oviparous sponge Chondrilla australiensis, using electron and light microscopy Fertilization is internal, and cleavage is total and equal Swimming coeloblastula larvae are present after 24 h, and are 50–75μm in diameter They are completely ciliated, spherical or ovoid, with a flattened posterior pole on which longer cilia occur Larvae are composed only of a monostratified layer consisting of a relatively small number of columnar, monociliated cells Intercellular junctions join the apical parts of the cells The small central cavity contains dense populations of bacterial and cyanobacterial symbionts After a free-swimming period of 24–36 h, larvae settle on the substratum by the anterior pole Metamorphosis occurs by the dedifferentiation and rearrangement of ciliated cells, which are the source of all adult cells in C australiensis Results of our research confirm the monophyly of order Chondr
TL;DR: It is shown that keratin-positive EWS/PNETs have evidence of epithelial differentiation ultrastructurally, and may possibly represent a more aggressive subset of the EWS-PNET group of tumors.
Abstract: Ewing's sarcoma/primitive neuroectodermal tumor (EWS/PNET) is an aggressive neoplasm of bone and soft tissue. Histologically, it is characterized by the presence of small round blue cells, which us...
TL;DR: Investigation of the structure of holocellulose softwood pulp fibres revealed that during hydrolysis of one hemicellulose, part of the other was also dissolved, indicating that the two hemICElluloses are to some extent linked to each other in the structure.
Abstract: To increase our knowledge of the ultrastructure within softwood fibres, enzymatic treatment, thermoporosimetry, light microscopy, and atomic force microscopy with image analysis were used to invest ...
TL;DR: Structure and ultrastructure changes that occurred during tissue culture of upper explants of hypocotyl (adjacent to cotyledons) of 10-d-old seedlings of Gentiana cruciata were studied to collect evidence of indirect somatic embryogenesis.
Abstract: Structure and ultrastructure changes that occurred during tissue culture of upper explants of hypocotyl (adjacent to cotyledons) of 10-d-old seedlings of Gentiana cruciata were studied. The explants were cultured on Murashige and Skoog induction medium supplemented with 1.0 mg l−1 dicamba +0.1 mg l−1 naphthaleneacetic acid +2.0 mg l−1 benzyladenine +80.0 mg l−1 adenine sulfate. The initial response of the explant and callus formation were ultrastructurally analyzed during the first 11 d of culture. After 6–8 wk, various methods were employed to collect evidence of indirect somatic embryogenesis. After 48 h of culture, the earliest cell response was cell division of epidermis and primary cortex. There were numerous disturbances of karyo- and cytokinesis, leading to formation of multinuclear cells. With time, the divisions ceased, and cortex cells underwent strong expansion, vacuolization and degradation. About the 6th day of culture, callus tissue proliferated and the initial divisions of vascular cylinder cells were observed. Their division appeared normal. Cells originating from that tissue were small, weakly vacuolated, with dense cytoplasm containing active-looking cell organelles. Numerous divisions occurred in the vascular cylinder, which led to its expansion and the formation of embryogenic callus tissue. During the 6–8th wk of culture, in the proximal end of the explant, masses of somatic embryos were formed from outer parts of intensively proliferating tissue.
TL;DR: Three unrelated patients, one girl, one boy, and an adult female, aged 14, 11 and 41 years, respectively, at the time of biopsy, revealed lysosomal glycogen storage, autophagic vacuoles and peculiar globular inclusions of distinct ultrastructure that indicate that in the late-onset type of GSD II such inclusions may not be rare.
Abstract: Three unrelated patients, one girl, one boy, and an adult female, aged 14, 11 and 41 years, respectively, at the time of biopsy, revealed lysosomal glycogen storage, autophagic vacuoles and peculiar globular inclusions of distinct ultrastructure, which were reducing but did not appear like true “reducing bodies” as described in the congenital myopathy “reducing body myopathy” All three patients had residual activity of acid α-glucosidase in their muscle biopsy samples Leukocytes in the girl showed normal acid α-glucosidase activity, but in the boy activity was reduced Molecular genetic analysis of the GAA gene revealed disease-causing mutations in each patient: H568L/R672W, IVS1–13T>G/G615F, and IVS1–13T>G/IVS1–13T>G Although only one patient with such globular inclusions has been reported up to now, the three patients described here indicate that in the late-onset type of GSD II such inclusions may not be rare
TL;DR: The morphology of Echinostoma paraensei was studied using transmission electron microscopy and found that the epidermal cells that cover the larval body have unique nuclear morphology, many mitochondria and vesicles being attached to the interepidermal ridges by a septate junction.
Abstract: The morphology of Echinostoma paraensei was studied using transmission electron microscopy. The terebratorium region has many electrondense secretory granules and many folds on the surface. The epidermal cells that cover the larval body have unique nuclear morphology, many mitochondria and vesicles being attached to the interepidermal ridges by a septate junction. The cilia present the organization 9+2 and a typical structure with a shaft, axosome, basal body and rootlet. Below the epidermal cells there is a layer of circular muscle and, adjacent to it, a layer of longitudinal muscle fibers. The excretory system has two flame cells, with internal and external ribs and leptotriches at the barrel region, an excretory vesicle and an excretory pore.
Journal Article•
TL;DR: Reversible changes after freezing were observed in tissue pretreated with vitrification solution: dilation of cell membranes, mitochondria with electron-lucent vessels, aggregation of numerous vesicles, and degradation of starch in amyloplasts.
Abstract: The influence of increased concentrations of sucrose, 0.4 M sorbitol, DMSO and vitrification solution (PVS2) on the ultrastructure of non-frozen and frozen suspensions of Gentiana tibetica King ex Hook. F.tissue cells was investigated. Embryogenic aggregates were composed of three groups of cells of different size with various types of plastids. The ultrastructural changes resulting from increasing the sucrose concentration in the medium from 3 to 6 percent for 4 weeks and from treatment with 0.4 M sorbitol for 48 h were similar. Observations showed replacement of large vacuoles by numerous small ones, condensation of cytoplasm, accumulation of starch, and fragmentation of endoplasmic reticulum. Treatment with PVS2 led to degradation of starch, coalescence of amyloplasts and to shrinking of nucleoli from the third group of cells when originating from 6 percent sucrose medium. The mitochondria initially had various shapes, but after PVS2 treatment showed only spherical shapes with sparse cristae. After programmed freezing of tissue protected by sorbitol and DMSO, lethal damage was observed: membrane and nuclei degradation, and cell destruction. Reversible changes after freezing were observed in tissue pretreated with vitrification solution: dilation of cell membranes, mitochondria with electron-lucent vessels, aggregation of numerous vesicles, and degradation of starch in amyloplasts. In cells cooled by a vitrification method, cell organelles appeared normal as early as 5 h after thawing, and anomalies were not observed after 48 h of post-thawing culture.
TL;DR: The microstructural and ultrastructural features of the equine lingual tonsil were studied in five young horses and showed strong affinity for Soybean, Phosphocarpus tetragonolobus 1, Ulex europaeus, and Griffonia simplicifolia 1 isolectin‐B4, which may be useful for embryological and microbiological investigations.
Abstract: Summary
The microstructural and ultrastructural features of the equine lingual tonsil were studied in five young horses. Located at the root of the tongue it presented an irregular surface with rounded elevations, numerous folds and crypts. Stratified squamous non-keratinized epithelium lining its outer surface was modified by heavy infiltration of lymphoid cells to form reticular epithelium within the crypt. The latter implies a role in initiating and maintaining immune responses to incoming infectious agents and antigens. Lamellated structures resembling Hassall's corpuscle were observed towards the outer surface epithelium. Microplicae were visible by scanning electron microscopy on the surface of both the outer and reticular epithelia. No microvillus cells resembling M cells were observed. The stratum superficiale of the reticular epithelium showed strong affinity for Soybean (SBA), Phosphocarpus tetragonolobus 1 (WBA 1), Ulex europaeus (UEA) and Griffonia simplicifolia 1 isolectin-B4 (GS1-B4). The characteristic lectin binding patterns may be useful for embryological and microbiological investigations. Vimentin filaments were not detected consistent with absence of M cells. Mucus glandular acini in the deeper lamina propria mucosae contained glycogen, acidic, neutral and weakly sulphated mucopolysaccharides. Transmission electron microscopy revealed that the layers of the outer surface and reticular epithelia shared characteristic features except the stratum superficiale, which had nuclei of varying shapes and an abundance of cell organelles. A few mast cells with electron lucent granules and myelinated nerve fibres were localized in the deeper portion.
TL;DR: The anatomy, histology and ultrastructure of the digestive tract of Orthrias angorae (Steindachner, 1897) were investigated using light microscopy, scanning electron microscope (SEM) and transmission electron microscopy (TEM).
Abstract: The anatomy, histology and ultrastructure of the digestive tract of Orthrias angorae (Steindachner, 1897) were investigated using light microscopy, scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The histological structure consists of four layers: mucosa, submucosa, muscularis and serosa. The esophageal mucosa consists of undifferentiated basal epithelial cells, mucous cells and surface epithelial cells. It was observed that the J-shaped stomach had a meshwork of folds in the cardiac region, and longitudinal folds in the fundic and pyloric regions. A single layer of columnar cells, PAS positive only in their apical portions, forms the epithelium. The convoluted tube-shape intestine is lined by simple columnar epithelial cells, which have microvilli at the apical surface. The wall of the esophagus and stomach are thicker than that of the intestine because of the thick muscle layer. There were numerous goblet cells in the intestine. There were numerous gastric glands in the submucosa layer ofthe cardiac stomach, but none were present in the pyloric region of the stomach. There were no pyloric caeca between the stomach and intestine. The enterocytes with microvilli contained rough endoplasmic reticulum, ribosomes and rounded bodies, and the gastric cells contained a well-developed Golgi apparatus.
TL;DR: It is concluded that germination of tetraspores in G. floridanum depends on a basic process consisting of: attachment, cell wall deposition, activation of dictyosomes, mobilisation of starch accumulated during sporogenesis, polarised vacuolation, germ tube formation, and cell division.
Abstract: Spore germination is a crucial step in the dispersion and establishment of algae. Here we describe for the first time the ultrastructure of the initial stages of the tetraspore germination of Gelidium floridanum, a species considered to be of potential economical value in Brazil. The stages of the germination process of G. floridanum tetraspores were studied under light and transmission electron microscopy. When released, the spores had no cell walls and were surrounded by a mucilage envelope that enabled primary attachment of the spore to the substratum. Following spore release, numerous tubular invaginations of the plasma membrane became apparent. These structures appeared to be connected to the endoplasmic reticulum and may play a role in the transport of cell wall material. Small vesicles with fibrillar content, although abundant in the tetraspores, were no longer seen in the sporelings, suggesting that these vesicles contain the precursors of the cell wall material that accumulates during sp...
TL;DR: TRPC1 channels in sinus endothelial cells of the spleen might play an important role in controlling blood cell passage through phenomena including cytoskeletal reorganization, cell retraction, and disassembly of adherens junctions.
Abstract: The ultrastructural localization of transient receptor potential C1 (TRPC1) channels in the sinus endothelial cells of rat spleen was examined by confocal laser scanning and electron microscopy. In addition, the localization of the closely associated proteins and channels, VE-cadherin, calreticulin, inositol-1,4,5-trisphosphate receptors type 1 (IP3R1), and ryanodine receptor (RyR), was also examined. Immunofluorescence microscopy of tissue cryosections revealed TRPC1 channels to be localized within the cytoplasm, in the superficial layer of the apical and basal parts of the cells, and in the junctional area of the adjacent endothelial cells. The distribution of Ca2+-storing tubulovesicular structures within endothelial cells was established by using tissue sections treated with osmium ferricyanide. Electron microscopy revealed densely stained tubulovesicular structures closely apposed to the plasma membrane and that occasionally ran closely parallel to the plasma membrane and near the caveolae and junctional apparatus. Immunolocalization analysis at the electron microscopy level using immunogold bound to the secondary antibody confirmed that TRPC1 channels were localized in the plasma membrane, caveolae, and vesicular structures in the subplasmalemmal cytoplasm of sinus endothelial cells. Calreticulin was predominantly localized in endoplasmic reticulum. IP3R1 and RyR, considered to be type 3, were colocalized in endoplasmic reticulum in proximity to the plasma membrane and caveolae. Thus, TRPC1 channels in sinus endothelial cells of the spleen might play an important role in controlling blood cell passage through phenomena including cytoskeletal reorganization, cell retraction, and disassembly of adherens junctions.
TL;DR: Quantitative cell and organelle dynamics of the male gamete-producing lineage of Plumbago zeylanica were examined using serial transmission electron microscopic reconstruction at five stages of development from generative cell inception to sperm cell maturity to suggest a highly competitive cytoplasmic environment that would tend to eliminate residual organellar heterogeneity.
Abstract: Quantitative cell and organelle dynamics of the male gamete-producing lineage of Plumbago zeylanica were examined using serial transmission electron microscopic reconstruction at five stages of development from generative cell inception to sperm cell maturity. The founder population of generative cell organelles includes an average of 3.88 plastids, 54.9 mitochondria, and 3.7 vacuoles. During development the volume of the pollen grain increases from 6,200 μm3 in early microspores to 115,000 μm3 at anthesis, cell volume of the male germ lineage decreases more than 67% from 362.3 μm3 to 118.4 μm3. By the time the generative cell separates from the intine, plastid numbers increase by >600%, mitochondria by 250%, and vesicles by 43 times. A cellular projection elongates toward and establishes an association with the vegetative nucleus; this leading edge contains plastids and numerous mitochondria. When the generative cell completes its separation from the intine, organellar polarity is reversed and plastids migrate to the opposite pole of the cell. Cytoplasmic microtubules are common in association with cellular organelles. Plastids accumulate at the distal end of the cell as a linked mass, apparently adhered by lateral electron dense regions. Before division of the highly polarized generative cell, plastids decrease in number by 16%, whereas mitochondria increase by ∼90% and vacuoles increase by ∼140% from the prior stage. After mitosis, the resultant sperm cells differ in size and organelle content. The sperm cell associated with the vegetative nucleus (Svn) contains 62.7% of the cytoplasm volume, 87% of the mitochondria, 280.4 vesicles (79% of those in the generative cell), and 0.6% of the plastids. At maturity, the Svn mitochondria increase by 31% and the cell contains an average of 0.4 plastids, 158.9 vesicles, and 0.36 microbodies. The mature unassociated sperm (Sua) contains 39.8 mitochondria (up 3.3%), 24.3 plastids (down 31%), 91.1 vesicles (up 54.9%), and 3.18 microbodies. The small number of organelles initially in the generative cell, followed by their rapid multiplication in a shrinking cytoplasm suggests a highly competitive cytoplasmic environment that would tend to eliminate residual organellar heterogeneity. Cell and cytoplasmic volumes vary as a consequence of fluctuations in the number and size of large vesicles or vacuoles, as well as loss of cytoplasmic volume by (1) formation of “false cells” involving amitotic cytokinesis, (2) “pinching off” of cytoplasm, and (3) dehydration of pollen contents prior to anthesis.
TL;DR: A primary smooth muscle tumor of the pleura that was discovered incidentally on chest X-ray in a 73-year-old man and diagnosed on CT-guided needle biopsy has a rewarding yield in providing the most likely diagnosis, predicting prognosis, and management planning.
Abstract: Primary smooth muscle tumor of the pleura is exceptionally rare. The authors describe a primary smooth muscle tumor of the pleura that was discovered incidentally on chest X-ray in a 73-year-old man. Magnetic resonance imaging demonstrated a 12 × 18 × 15-cm pleura-based mass arising from the posterior mediastinum. Computerized tomography (CT) guided needle cores from the pleura showed a primary smooth muscle tumor of undetermined malignant potential. Further excision of the whole tumor showed an intimate relation to pleura, and the diagnosis of leiomyosarcoma was made. The clinical, radiological, histopathological, immunohistochemical, and ultrastuctural findings were consistent with a primary smooth muscle tumor of the pleura. This is the seventh case in the literature of a primary smooth muscle tumor of the pleura, which, to the best of the authors' knowledge, is the first such case of the pleura to be diagnosed on CT-guided needle biopsy. In conclusion, this method of investigation is recommended since...
TL;DR: The detection of mycobacterial lipid antigens in situ at an ultrastructural level is currently a challenge, but new modifications can be used to address this.