scholarly journals Ultrastructure of the gills ciliary epithelium of Limnoperna fortunei (Dunker 1857), the invasive golden mussel

2021 ◽  
Author(s):  
Erico Tadeu Fraga Freitas ◽  
Amanda Maria Siqueira Moreira ◽  
Rayan Silva de Paula ◽  
Gabriela Rabelo Andrade ◽  
Marcela David de Carvalho ◽  
...  
Keyword(s):  
Epithelial Cells ◽  
High Efficiency ◽  
Population Control ◽  
Smooth Endoplasmic Reticulum ◽  
Deep Understanding ◽  
Ciliary Epithelium ◽  
Limnoperna Fortunei ◽  
Effective Strategies ◽  
Strong Adhesion ◽  
Branchial Epithelium

Abstract Background Limnoperna fortunei is a bivalve mollusk originally from southern Asia that invaded South America in the 1990's. Its high efficiency in pumping and filtering water and the capacity to promote strong adhesion to different substrates allowed the adaptation of this invasive species, associated with several environmental and economic damages. A deep understanding of the biology and ecology aspects of L. fortunei is necessary to outline effective strategies to manage its invasion. Mollusk gills are important structures responsible for several biological functions including breathing and feeding. In this work, we characterized the ultrastructure of L. fortunei gills and its ciliary epithelium using transmission and scanning electron microscopy. This is the first report of the L. fortunei gills ciliary epithelial cells visualized with high resolution and detailed morphology. Results The analysis showed a highly organized and large amount of ciliary structures (frontal cilia, laterofrontal cilia, and lateral cilia) on the entire length of the branchial epithelium. Mitochondria, smooth endoplasmic reticulum and glycogen granules were abundantly found in the epithelial cells of the gills, suggesting that all this energetic apparatus could be related to the morpho-functional structure of the cilia. Vesicles possibly containing mucus could also be observed in these cells, suggesting that they might be related to L. fortunei mechanism of selection and/or rejection of captured particles suspended in water. Conclusions Our data suggest the mechanism used by this mollusk for particles capture and selection, which could contribute to a better understanding of important aspects of invasion and decide on more efficient and economic strategies of population control.

Analysis of Ca2+ uptake into the smooth endoplasmic reticulum of permeabilised sternal epithelial cells during the moulting cycle of the terrestrial isopodPorcellio scaber

2002 ◽  
Vol 205 (13) ◽  
pp. 1935-1942 ◽  
Author(s):  
Monica Hagedorn ◽  
Andreas Ziegler
Keyword(s):  
Endoplasmic Reticulum ◽  
Epithelial Cells ◽  
Smooth Endoplasmic Reticulum ◽  
Cyclopiazonic Acid ◽  
Crystal Formation ◽  
Porcellio Scaber ◽  
Intracellular Compartments ◽  
Electron Microscopical ◽  
And Function ◽  
Moulting Cycle

SUMMARYIn terrestrial isopods, large amounts of Ca2+ are transported across anterior sternal epithelial cells during moult-related deposition and resorption of CaCO3 deposits. Because of its toxicity and function as a second messenger, resting cytosolic Ca2+ levels must be maintained below critical concentrations during epithelial Ca2+transport, raising the possibility that organelles play a role during Ca2+ transit. We therefore studied the uptake of Ca2+into Ca2+-sequestering organelles by monitoring the formation of birefringent calcium oxalate crystals in permeabilised anterior and posterior sternal epithelium cells of Porcellio scaber during Ca2+-transporting and non-transporting stages of the moulting cycle using polarised-light microscopy. The results indicate ATP-dependent uptake of Ca2+ into organelles. Half-maximal crystal growth at a Ca2+ activity, aCa, of 0.4 μmol l-1 and blockade by cyclopiazonic acid suggest Ca2+uptake into the smooth endoplasmic reticulum by the smooth endoplasmic reticulum Ca2+-ATPase. Analytical electron microscopical techniques support this interpretation by revealing the accumulation of Ca2+-containing crystals in smooth membranous intracellular compartments. A comparison of different moulting stages demonstrated a virtual lack of crystal formation in the early premoult stage and a significant fivefold increase between mid premoult and the Ca2+-transporting stages of late premoult and intramoult. These results suggest a contribution of the smooth endoplasmic reticulum as a transient Ca2+ store during intracellular Ca2+ transit.

scholarly journals Cell shape and intercellular adhesion regulate mitotic spindle orientation

2019 ◽  
Vol 30 (19) ◽  
pp. 2458-2468 ◽  
Author(s):  
Jingchen Li ◽  
Longcan Cheng ◽  
Hongyuan Jiang
Keyword(s):  
Cell Division ◽  
Epithelial Cells ◽  
Cell Fate ◽  
Cell Shape ◽  
Intercellular Adhesion ◽  
Shape Anisotropy ◽  
Spindle Orientation ◽  
Mitotic Spindles ◽  
Strong Adhesion ◽  
Fate Decision

Cell division orientation plays an essential role in tissue morphogenesis and cell fate decision. Recent studies showed that either cell shape or adhesion geometry can regulate the orientation of mitotic spindles and thereby the cell division orientation. However, how they together regulate the spindle orientation remains largely unclear. In this work, we use a general computational model to investigate the competitive mechanism of determining the spindle orientation between cell shape and intercellular adhesion in epithelial cells. We find the spindle orientation is dominated by the intercellular adhesion when the cell shape anisotropy is small, but dominated by the cell shape when the shape anisotropy is large. A strong adhesion and moderate adhesive size can ensure the planar division of epithelial cells with large apico-basal elongation. We also find the spindle orientation could be perpendicular to the adhesive region when only one side of the cell is adhered to an E-cadherin–coated matrix. But after the cell is compressed, the spindle orientation is governed by the cell shape and the spindle will be parallel to the adhesive region when the cell shape anisotropy is large. Finally, we demonstrate the competition between cell shape and tricellular junctions can also effectively regulate the spindle orientation.

scholarly journals The Impact of Natural Compounds on S-Shaped Aβ42 Fibril: From Molecular Docking to Biophysical Characterization

2020 ◽  
Vol 21 (6) ◽  
pp. 2017 ◽  
Author(s):  
Stefano Muscat ◽  
Lorenzo Pallante ◽  
Filip Stojceski ◽  
Andrea Danani ◽  
Gianvito Grasso ◽  
...  
Keyword(s):  
Deep Understanding ◽  
Natural Compounds ◽  
Inhibitory Mechanism ◽  
Biophysical Characterization ◽  
Beneficial Effects ◽  
Effective Strategies ◽  
Amyloid Aggregates ◽  
Dynamics Simulations ◽  
Preclinical And Clinical Studies ◽  
The Impact

The pursuit for effective strategies inhibiting the amyloidogenic process in neurodegenerative disorders, such as Alzheimer’s disease (AD), remains one of the main unsolved issues, and only a few drugs have demonstrated to delay the degeneration of the cognitive system. Moreover, most therapies induce severe side effects and are not effective at all stages of the illness. The need to find novel and reliable drugs appears therefore of primary importance. In this context, natural compounds have shown interesting beneficial effects on the onset and progression of neurodegenerative diseases, exhibiting a great inhibitory activity on the formation of amyloid aggregates and proving to be effective in many preclinical and clinical studies. However, their inhibitory mechanism is still unclear. In this work, ensemble docking and molecular dynamics simulations on S-shaped Aβ42 fibrils have been carried out to evaluate the influence of several natural compounds on amyloid conformational behaviour. A deep understanding of the interaction mechanisms between natural compounds and Aβ aggregates may play a key role to pave the way for design, discovery and optimization strategies toward an efficient destabilization of toxic amyloid assemblies.

scholarly journals Perovskite-molecule composite thin films for efficient and stable light-emitting diodes

2020 ◽  
Vol 11 (1) ◽  
Author(s):  
Heyong Wang ◽  
Felix Utama Kosasih ◽  
Hongling Yu ◽  
Guanhaojie Zheng ◽  
Jiangbin Zhang ◽  
...  
Keyword(s):  
Thin Films ◽  
High Efficiency ◽  
Light Emitting Diodes ◽  
Degradation Mechanism ◽  
Deep Understanding ◽  
Significant Progress ◽  
High Quality ◽  
Composite Thin Films ◽  
Light Emitting

AbstractAlthough perovskite light-emitting diodes (PeLEDs) have recently experienced significant progress, there are only scattered reports of PeLEDs with both high efficiency and long operational stability, calling for additional strategies to address this challenge. Here, we develop perovskite-molecule composite thin films for efficient and stable PeLEDs. The perovskite-molecule composite thin films consist of in-situ formed high-quality perovskite nanocrystals embedded in the electron-transport molecular matrix, which controls nucleation process of perovskites, leading to PeLEDs with a peak external quantum efficiency of 17.3% and half-lifetime of approximately 100 h. In addition, we find that the device degradation mechanism at high driving voltages is different from that at low driving voltages. This work provides an effective strategy and deep understanding for achieving efficient and stable PeLEDs from both material and device perspectives.

scholarly journals Stucco repair method for enclosing brick walls

2019 ◽  
Vol 135 ◽  
pp. 03047
Author(s):  
Alexandr Zholobov ◽  
Nadezhda Ivannikova ◽  
Olga Razinkova ◽  
Peter Dukhanin
Keyword(s):  
High Efficiency ◽  
Wall Structure ◽  
Brick Wall ◽  
Test Results ◽  
Repair Method ◽  
Internal Surfaces ◽  
Strong Adhesion ◽  
Additional Process ◽  
The Russian Federation ◽  
Repair Techniques

During the operation of buildings, plaster coatings of the external and internal enclosing surfaces of brick walls are subjected to various destructive influences. Existing methods of repairing plaster coatings do not fully ensure strong adhesion of the material of the repair layer of plaster to the surface of the repaired brick wall structure. In addition, these methods can only get rid of damage but do not improve the operational properties of the plaster layer of the repaired structure. Thus, the urgent problem is the development of an effective method of repairing plaster coatings on the surfaces of brick walls, due to which it will become possible to ensure the monolithic of the repaired plastering structure. In order to address the shortcomings of the existing plaster coating repair techniques on the surfaces of the brick walls and finding ways to improve it, by the authors investigated the possibility and the expediency of performing the repair of additional process steps. A feature of this repair method is the use of preheated plaster mortar, flexible plaster molding, as well as compaction of the stucco mortar in the contact area with the repaired brick wall structure with a deep plate compactor. The test results of samples of plaster coatings manufactured by the proposed method showed the high efficiency and feasibility of using this method for repairs on the external and internal surfaces of walling of brick walls and are mentioned in the patent for the invention of the Russian Federation. The performance characteristics of the plaster are significantly increased as a result of the application of this method, and, consequently, the service life of the plaster coating is increased several times.

scholarly journals Studies on microperoxisomes. VII. Pigment epithelial cells and other cell types in the retina of rodents.

1975 ◽  
Vol 65 (2) ◽  
pp. 324-334 ◽  
Author(s):  
P M Leuenberger ◽  
A B Novikoff
Keyword(s):  
Epithelial Cells ◽  
Vascular Endothelial Cells ◽  
Smooth Endoplasmic Reticulum ◽  
Photoreceptor Cells ◽  
Cell Types ◽  
Vascular Endothelial ◽  
Pigment Epithelial ◽  
Large Numbers ◽  
And Storage ◽  
Pigment Epithelial Cells

The pigment epithelial cell of the retina actively participates in two aspects of lipid metabolism: (a) the fatty acid esterification of vitamin A and its storage and transport to the photoreceptors, and (b) the phagocytosis and degradation of the lipoprotein membrane disks shed from the photoreceptor cells. Study of the pigment epithelial cells of adult albino and pigmented rodents has revealed the abundance of an organelle, microperoxisomes, not previously known to exist in this cell type. The metabolism, transport, and storage of lipids are major functions of other cell types which possess large numbers of microperoxisomes associated with a highly developed smooth endoplasmic reticulum. Microperoxisomes were encountered, but relatively rarely, in Müller cells and vascular endothelial cells. A tubular system in photoreceptor terminals is reactive in the cytochemical procedure used to visualize microperoxisomes.

scholarly journals Quantitative immunocytochemical localization of Na+,K+-ATPase in rat ciliary epithelial cells.

1989 ◽  
Vol 37 (9) ◽  
pp. 1353-1361 ◽  
Author(s):  
T Okami ◽  
A Yamamoto ◽  
K Omori ◽  
M Akayama ◽  
M Uyama ◽  
...  
Keyword(s):  
Epithelial Cells ◽  
Aqueous Humor ◽  
Ciliary Body ◽  
Protein A ◽  
Ultrastructural Localization ◽  
Immunoblot Analysis ◽  
Alpha Subunit ◽  
Ciliary Epithelium ◽  
Immunocytochemical Localization ◽  
Gold Particles

Ultrastructural localization of Na+,K+-ATPase in rat ciliary epithelium was investigated quantitatively by the protein A-gold technique, using an affinity-purified antibody against the alpha-subunit of Na+,K+-ATPase. Immunoblot analysis showed that the antibody bound specifically to the alpha-subunit of Na+,K+-ATPase in the ciliary body. Gold particles were found mainly on the basolateral surfaces of both the pigmented epithelial (PE) and nonpigmented epithelial (NPE) cells with an approximately twofold higher labeling density in the PE cells. A few gold particles were also found on the apical and ciliary channel surfaces of the PE cells, whereas no significant binding was found on the apical surfaces of the NPE cells. The basolateral surfaces of PE and NPE cells are markedly infolded and are much greater in area than the apical surfaces. This means that Na+,K+-ATPase is almost exclusively located on the basolateral surfaces of both the NPE and PE cells. We suggest that the Na+,K+-ATPase of both the NPE and PE cells play an important role in the formation of aqueous humor.

scholarly journals Extracellular RNA moves from the glomerulus to the renal tubule

2021 ◽  
Author(s):  
Robert W Hunter ◽  
Sujai Kumar ◽  
Richard JM Coward ◽  
Amy H Buck ◽  
James W Dear
Keyword(s):  
Epithelial Cells ◽  
High Efficiency ◽  
White Blood Cells ◽  
Indirect Evidence ◽  
Tubular Epithelial Cells ◽  
Renal Tubular Epithelial Cells ◽  
Extracellular Rna ◽  
Tubular Cells ◽  
Renal Tubular ◽  
Negative Controls

There is a wealth of indirect evidence that extracellular RNA (exRNA) signalling can regulate renal tubular epithelial cell function. However, the physiological importance of this signalling is uncertain. We sought to determine the extent of extracellular RNA transfer between cells in a healthy kidney. We tested the hypothesis that RNA travels from glomerular podocytes to renal tubular epithelial cells. We developed a method to track exRNA in the kidney using SLAMseq (SH-linked alkylation for the metabolic sequencing of RNA in tissue). We crossed podocin-Cre mice with floxed-stop-UPRT mice to express recombinant uracil phosphoribosyl transferase (UPRT) in podocytes. Mice were injected with the modified nucleobase 4-thiouracil, which is incorporated into nascent RNA with high efficiency only in UPRT-expressing cells. We harvested glomeruli or tubular cells, extracted RNA and prepared libraries for SLAMseq, in which sites of mRNA labelling with 4-thiouracil are detected as T>C conversions in 3'UTRs. In glomeruli, we detected labelling of known podocyte genes but not of genes known to be restricted to endothelial, renal tubular or white blood cells. Setting a false-discovery rate of 1%, the proportion of genes deemed to be labelled with high confidence was 7.1% (95% confidence interval 6.8-7.4%) in 4TU-treated podocyte-UPRT mice, 2.5% (2.3-2.7%) in Cre-negative controls and 1.0% (0.9-1.1%) in 4TU-naive controls. In tubular cells, we detected a small but statistically significant increase in RNA labelling in podocyte-UPRT mice compared to Cre-negative controls (p = 7.4x10-16 in a zero-inflated Poisson regression model). We conclude that RNA is transferred from podocytes to renal tubular epithelial cells in vivo under physiological conditions. Our model provides the opportunity to explore the consequences of this novel signalling pathway in health and kidney disease.

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