scholarly journals The Role of Epithelial Stat3 in Amelogenesis during Mouse Incisor Renewal

2018 ◽  
Vol 205 (2) ◽  
pp. 63-71
Author(s):  
Bin Zhang ◽  
Bo Meng ◽  
Edward Viloria ◽  
Adrien Naveau ◽  
Bernhard Ganss ◽  
...  
Keyword(s):  
Adult Mouse ◽  
Electron Microscopy Analysis ◽  
Kallikrein 4 ◽  
Enamel Mineralization ◽  
Microscopy Analysis ◽  
Mouse Incisor ◽  
First Time ◽  
Transcription 3 ◽  
Tomography Analysis

The aim of this study was to evaluate the role of epithelial signal transducer and activator of transcription 3 (STAT3) in mouse incisor amelogenesis. Since Stat3 is expressed in the epithelial component of developing and adult mouse teeth, we generated and analyzed Krt14Cre/+;Stat3fl/fl mutant mice in which Stat3 was inactivated in epithelia including ameloblast progenitors and ameloblasts, the cells responsible for enamel formation. Histological analysis showed little enamel matrix in mutant incisors compared to controls. Delayed incisor enamel mineralization was demonstrated using micro-computed X-ray tomography analysis and was supported by an increase in the pre-expression distance of enamel-enriched proteins such as amelogenin, ameloblastin, and kallikrein-4. Lastly, scanning electron microscopy analysis showed little enamel mineralization in mutant incisors underneath the mesial root of the 1st molar; however, the micro-architecture of enamel mineralization was similar in the erupted portion of control and mutant incisors. Taken together, our findings demonstrate for the first time that the absence of epithelial Stat3 in mice leads to delayed incisor amelogenesis.

scholarly journals Antiparasitic Properties of Cardiovascular Agents against Human Intravascular Parasite Schistosoma mansoni

2021 ◽  
Vol 14 (7) ◽  
pp. 686
Author(s):  
Raquel Porto ◽  
Ana C. Mengarda ◽  
Rayssa A. Cajas ◽  
Maria C. Salvadori ◽  
Fernanda S. Teixeira ◽  
...  
Keyword(s):  
Schistosoma Mansoni ◽  
Screening Strategy ◽  
Early Infection ◽  
Global Public Health ◽  
Parasitic Worm ◽  
Electron Microscopy Analysis ◽  
Health Significance ◽  
Microscopy Analysis

The intravascular parasitic worm Schistosoma mansoni is a causative agent of schistosomiasis, a disease of great global public health significance. Praziquantel is the only drug available to treat schistosomiasis and there is an urgent demand for new anthelmintic agents. Adopting a phenotypic drug screening strategy, here, we evaluated the antiparasitic properties of 46 commercially available cardiovascular drugs against S. mansoni. From these screenings, we found that amiodarone, telmisartan, propafenone, methyldopa, and doxazosin affected the viability of schistosomes in vitro, with effective concentrations of 50% (EC50) and 90% (EC90) values ranging from 8 to 50 µM. These results were further supported by scanning electron microscopy analysis. Subsequently, the most effective drug (amiodarone) was further tested in a murine model of schistosomiasis for both early and chronic S. mansoni infections using a single oral dose of 400 mg/kg or 100 mg/kg daily for five consecutive days. Amiodarone had a low efficacy in chronic infection, with the worm and egg burden reduction ranging from 10 to 30%. In contrast, amiodarone caused a significant reduction in worm and egg burden in early infection (>50%). Comparatively, treatment with amiodarone is more effective in early infection than praziquantel, demonstrating the potential role of this cardiovascular drug as an antischistosomal agent.

Three-Dimensional TEM Tomography Analysis of Epitaxially Assembled Perovskite Oxide Nanocrystalline Particles

2008 ◽  
Vol 388 ◽  
pp. 127-130
Author(s):  
Naoki Iwaji ◽  
Hiromichi Takebe ◽  
Makoto Kuwabara
Keyword(s):  
Three Dimensional ◽  
Hydrothermal Condition ◽  
Perovskite Oxide ◽  
Transmission Electron Microscopy Analysis ◽  
Transmission Electron ◽  
Nanocrystalline Particles ◽  
Electron Microscopy Analysis ◽  
Microscopy Analysis ◽  
Tomography Analysis ◽  
Catio3 Nanoparticles

We investigated epitaxial assembly in aggregates of CaTiO3 nanoparticles, which were synthesized under a hydrothermal condition at 150°C using water/ethanol solvent, by transmission electron microscopy analysis combined with a three-dimensional tomography technique. The obtained results indicate that epitaxial assembly is involved in the crystal growth of CaTiO3 nanoparticles, and that in aggregates of CaTiO3 nanoparticles epitaxial assembly occur on their {101} planes.

Production and characterization of titanium and iron oxide nano-sized thin films

2001 ◽  
Vol 16 (6) ◽  
pp. 1559-1564 ◽  
Author(s):  
E. Comini ◽  
G. Sberveglieri ◽  
M. Ferroni ◽  
V. Guidi ◽  
C. Frigeri ◽  
...  
Keyword(s):  
Thin Films ◽  
Iron Oxide ◽  
Gas Sensing ◽  
Iron Concentration ◽  
Radio Frequency Sputtering ◽  
Electron Microscopy Analysis ◽  
Microscopy Analysis ◽  
Reproducible Method

We present a simple and reproducible method to obtain TiO2 and Fe2O3 mixed-oxide thin films by reactive radio-frequency sputtering. The influence of iron concentration on the structural properties of the layers has been studied. Structural characterization, carried out by electron microscopy analysis, allowed one to correlate the inhibition of the grain growth of titania to the presence of iron oxide and to its segregation at grain boundaries. This behavior should be ascribed to a superficial-tension phenomenon. As a possible application of these thin films, we have investigated the gas-sensing properties toward CO, with particular focus on the role of Fe. The layers were capable to sense CO down to the level requested for environmental monitoring.

Sponge fauna associated with a Mediterranean deep-sea coral bank

2005 ◽  
Vol 85 (6) ◽  
pp. 1341-1352 ◽  
Author(s):  
Caterina Longo ◽  
Francesco Mastrototaro ◽  
Giuseppe Corriero
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Mediterranean Sea ◽  
Endemic Species ◽  
Deep Sea ◽  
Southern Italy ◽  
Electron Microscopy Analysis ◽  
Microscopy Analysis ◽  
First Time ◽  
Scanning Electron

Thirty species of sponges (29 Demospongiae, 1 Hexactinellida) have been recorded in association with a white coral bank situated off Cape S. Maria di Leuca (southern Italy) at depths ranging from 430 to 1160 metres. Notwithstanding the occurrence of clearly eurybathic species, two depth-dependent sponge groups can be identified along the bathymetric gradient. Two species, Geodia nodastrella and Plocamiopsis signata, are reported for the first time from the Mediterranean Sea. The sponge assemblage shows a higher affinity with the fauna from the Boreal region, with very low number of Mediterranean endemic species. Systematic notes concerning the poorly known and intriguing species, studied using scanning electron microscopy analysis, are reported.

scholarly journals Structural investigation of ACE2 dependent disassembly of the trimeric SARS-CoV-2 Spike glycoprotein

2020 ◽  
Author(s):  
Dongchun Ni ◽  
Kelvin Lau ◽  
Frank Lehmann ◽  
Andri Fränkl ◽  
David Hacker ◽  
...  
Keyword(s):  
Structural Rearrangement ◽  
Host Cells ◽  
Surface Glycoprotein ◽  
Angiotensin Converting Enzyme 2 ◽  
Cryo Electron Microscopy ◽  
Monomeric Complex ◽  
Electron Microscopy Analysis ◽  
Microscopy Analysis ◽  
Viral Surface

AbstractThe human membrane protein Angiotensin-converting enzyme 2 (hACE2) acts as the main receptor for host cells invasion of the new coronavirus SARS-CoV-2. The viral surface glycoprotein Spike binds to hACE2, which triggers virus entry into cells. As of today, the role of hACE2 for virus fusion is not well understood. Blocking the transition of Spike from its prefusion to post-fusion state might be a strategy to prevent or treat COVID-19. Here we report a single particle cryo-electron microscopy analysis of SARS-CoV-2 trimeric Spike in presence of the human ACE2 ectodomain. The binding of purified hACE2 ectodomain to Spike induces the disassembly of the trimeric form of Spike and a structural rearrangement of its S1 domain to form a stable, monomeric complex with hACE2. This observed hACE2 dependent dissociation of the Spike trimer suggests a mechanism for the therapeutic role of recombinant soluble hACE2 for treatment of COVID-19.

scholarly journals Protein crowding mediates membrane remodeling in upstream ESCRT-induced formation of intraluminal vesicles

2020 ◽  
Vol 117 (46) ◽  
pp. 28614-28624
Author(s):  
Susanne Liese ◽  
Eva Maria Wenzel ◽  
Ingrid Kjos ◽  
Rossana Rojas Molina ◽  
Sebastian W. Schultz ◽  
...  
Keyword(s):  
Degradation Pathway ◽  
Bending Rigidity ◽  
Lysosomal Degradation ◽  
Endosomal Sorting ◽  
Electron Microscopy Analysis ◽  
Steep Decline ◽  
Microscopy Analysis ◽  
Protein Crowding ◽  
Membrane Shape

As part of the lysosomal degradation pathway, the endosomal sorting complexes required for transport (ESCRT-0 to -III/VPS4) sequester receptors at the endosome and simultaneously deform the membrane to generate intraluminal vesicles (ILVs). Whereas ESCRT-III/VPS4 have an established function in ILV formation, the role of upstream ESCRTs (0 to II) in membrane shape remodeling is not understood. Combining experimental measurements and electron microscopy analysis of ESCRT-III–depleted cells with a mathematical model, we show that upstream ESCRT-induced alteration of the Gaussian bending rigidity and their crowding in concert with the transmembrane cargo on the membrane induce membrane deformation and facilitate ILV formation: Upstream ESCRT-driven budding does not require ATP consumption as only a small energy barrier needs to be overcome. Our model predicts that ESCRTs do not become part of the ILV, but localize with a high density at the membrane neck, where the steep decline in the Gaussian curvature likely triggers ESCRT-III/VPS4 assembly to enable neck constriction and scission.

Parvalbumin is overexpressed in the late phase of pharmacological preconditioning in skeletal muscle

2013 ◽  
Vol 91 (11) ◽  
pp. 966-972
Author(s):  
Rosario Solis ◽  
Elba D. Carrillo ◽  
Ascención Hernández ◽  
María C. García ◽  
Jorge A. Sánchez
Keyword(s):  
Skeletal Muscle ◽  
Adult Mouse ◽  
Late Phase ◽  
Oxygen Species ◽  
Partial Protection ◽  
Intracellular Ca ◽  
Ros Scavenger ◽  
First Time ◽  
Pharmacological Preconditioning

Pharmacological preconditioning (PPC) with mitochondrial ATP-sensitive K+ channel openers such as diazoxide, provides protection against ischemia in cardiac muscle, skeletal muscle, and other tissues. Effects on Ca2+ homeostasis during the late phase of PPC have been described in cardiomyocytes, but no information is available regarding intracellular Ca2+ changes in skeletal muscle fibers during late PPC. Intracellular Ca2+ signals were measured in single fibers of adult mouse skeletal muscle, with fluorescent probes, 48 h after the administration of diazoxide. Parvalbumin levels in the myofibers were quantitated by Western blot. Diazoxide induction of late PPC was confirmed by partial protection of muscles from peroxide-induced damage. Late PPC was associated with a significant decrease in the duration of Ca2+ signals during single twitches and tetanus with no changes in peak values. This effect was prevented by the reactive oxygen species (ROS) scavenger tiron. Late PPC was accompanied by a 30% increase in parvalbumin levels, and this effect was also blocked by tiron. Our data show, for the first time, a role of parvalbumin in late PPC in skeletal muscle.

scholarly journals Primer Reporte del Virus del Rayado del Banano (BSV) Afectando Plantaciones de Plátano (Musa AAB Simmonds), Caña de azúcar (Sacharum officinarum) y Achira (Canna edulis) en Colombia

1996 ◽  
Vol 1 (1) ◽  
pp. 35 ◽  
Author(s):  
Helena Reichel ◽  
Silvio Belalcázar ◽  
Gladys Múnera ◽  
Emilio Arévalo ◽  
Javier Narváez
Keyword(s):  
Saccharum Officinarum ◽  
Streak Virus ◽  
Banana Streak Virus ◽  
First Report ◽  
Electron Microscopy Analysis ◽  
Microscopy Analysis ◽  
Polyclonal Antisera ◽  
Foliar Tissue ◽  
First Time ◽  
Das Elisa

<p>En noviembre de 1995, en los Municipios de Andes, Venecia e Hispania (Antioquia), La Tebaida y Montenegro (Quindío), se observaron hojas de plantas del don Dominico-Hartón (Musa AAB Simmonds) con rayas cloróticas y necróticas, síntomas que caracterizan la enfermedad del rayado del banano. En ocasiones las plantas presentaban síntomas de mosaico en el pseudotallo y el engrosamiento y/o rompimiento de la base del mismo. Además, en las cercanías de las plantaciones de plátano de los Municipios de Andes y Montenegro, se observaron respectivamente plantas de caña de azúcar (Saccharum officinarum) con síntomas de clorosis y de achira (Canna edulis) con síntomas de mosaico leve en sus hojas. Muestras de tejido foliar de éstas tres especies de plantas fueron analizadas para detectar la presencia del badnavirus del rayado del banano (BSV) y del virus del mosaico del pepino (CMV), mediante la prueba serológica DAS-ELISA, empleando anticuerpos policlonales comerciales (AGDIA Inc., Elkhart, IN). En el caso del plátano, en la región de Antioquia únicamente se detectó el BSV en el so% de las plantas sintomáticas analizadas, mientras que en el Quindío, el 6oo/o de las plantas estuvieron infectadas simultáneamente por BSV y CMV. El BSV se detectó también en muestras de tejido foliar de caña de azúcar y achira, pero en ningún caso resultaron positivas para el CMV, según la prueba DAS-ELISA. El análisis mediante microscopía electrónica de immunoabsorbancia (ISEM) del tejido foliar de plátano y caña de azúcar infectado, indicó la presencia de partículas baciliformes típicas del BSV de aproximadamente 30 x 110 nm. Hasta donde conocemos, este es el primer reporte sobre la presencia del BSV afectando plátano, caña de azúcar y achira en Colombia y es la primera vez que se reporta a la achira como hospedero de éste virus en el mundo.</p><p><strong><br /></strong></p><p><strong>First Report of Banana Streak Virus (BSV) Infecting Plantain (Musa AAB Simmonds), Sugar cane (Sacharumofficinarum) and Achira (Canna edulis) in Colombia</strong></p><p>Viruslike symptoms of yellow striate mosaic to necrotic streaks were observed on plantain leaves of the cultivar Dominico-Hartón (Musa AAB Simmonds) in the municipalities of Andes, Venecia and Hispania (Antioquia) and Tebaida and Montenegro (Quindío), Colombia. Symptoms sometimes included mosaic and swelling at the base of the pseudostem. Furthermore, in the neighborhood of the plantain crops, at the localities of Andes and Montenegro, it was observed respectively plants of sugarcane (Saccharum officinarum L.) with chlorotic foliar tissue and of achira (Canna edulis L.) with symptoms of mild mosaic in their leaves. The foliar tissue of symptomatic plants of these three species, was tested for banana streak virus (BSV ) and cucumber mosaic virus (CMV ) by double antibody sandwich enzime-linked immunosorbent assay (DAS-ELISA) with commercial polyclonal antisera (Agdia Inc., Elkhart, IN). BSV was detected in samples of all plant species. In Plantain, so% of the examined plants from the Antioquia region were infected by BSV, but not CMV; whereas, at the Quindío region, 6o% of the plants were simultaneously infected by both viruses, as detected by DAS- ELISA. CMV was not detected in foliar tissue of either sugarcane or achira plants. Immunosorbent electron microscopy analysis (ISEM) of BSV infected foliar tissue of plantain and sugarcane, showed the presence of viral bacilliform particles measuring ca. 30 x 110 nm, typical of BSV. Up to our knowledge, this is the first report of BSV infecting Musa spp., Saccharum officinarum and Canna edulis in Colombia, and the first time that Canna edulis is reported as a host for this virus.</p>

A Novel Sphingomyelin Synthase Gene, SMS1-Regulated Sphingomyelin/Ceramide-Rich Microdomain Plays a Crucial Role in Fas-Mediated Apoptosis.

Blood ◽  
2004 ◽  
Vol 104 (11) ◽  
pp. 1266-1266
Author(s):  
Michihiko Miyaji ◽  
Shohei Yamaoka ◽  
Jin Zhe Xiong ◽  
Ryuichi Amakawa ◽  
Tsuneyo Mimori ◽  
...  
Keyword(s):  
Cell Death ◽  
Crucial Role ◽  
Apoptotic Cell ◽  
Cholesterol Content ◽  
Sphingomyelin Synthase ◽  
Microscopy Analysis ◽  
Induced Apoptosis ◽  
Lipid Microdomain ◽  
First Time

Abstract Lipid microdomain consisting of sphingolipids, glycosphingolipids and cholesterol plays an important role in mediating cell death signals. Although functional analysis of lipid microdomain is conventionally performed by exclusion of cholesterol tightly binding with sphingomyein (SM), the exact role of SM in microdomain in signal transduction remains to be cleared. Since we for the first time obtained cDNA (SMS1) responsible for SM synthesis, it became possible to investigate the role of SM in the membrane without affecting cholesterol content. We here examine the role of SM/ceramide-rich microdomain in Fas-induced apoptosis using the SM-deficient cells and its revertant cells by transfection with SMS1. SM synthase-defective WR19L cells transfected with human-Fas gene (WR/Fas-SM(-)), and its functional revertant cells by transfection with SMS1 (WR/Fas-SMS1) were established. Both SMS1 cells and SM(-) cells expressed similar levels of CD44, CD90, CD95 (Human) and LFA-1 by FACS analysis. Although the levels of cholesterol and GM1-ganglioside on the surface of the membrane were similar in both cells, SM was detected only on the surface of SMS1 cells by FACS and confocal microscopy analysis. Fas crosslinking induced not only higher rate of apoptotic cell death, but also translocation of Fas into TritonX-100-insoluble fractions with a significant increase of ceramide in SMS1 cells as compared with SM(-) cells. After increase of SM and ceramide in microdomain, more efficient aggregation of Fas was detected with increase of DISC formation, resulting in activation of caspase-8 and 3 and decrease of mitochondrial membrane potential in SMS-1 cells than SM(-) cells. Our results clearly demonstrate that SM and ceramide in microdomain of plasma membrane plays a crucial role in Fas clustering and aggregation requires for activation of apoptosis-inducing signals.

The Study of Impact Rule of Si Element on Cu/Al Composite Interface Compounds

2014 ◽  
Vol 887-888 ◽  
pp. 43-48
Author(s):  
Min Wang ◽  
Ping Wang ◽  
Dong Xu Chang ◽  
Qian Zhang ◽  
Xin Zhang ◽  
...  
Keyword(s):  
Comparison Group ◽  
Aluminum Composite ◽  
Al Composite ◽  
Composite Interface ◽  
Electron Microscopy Analysis ◽  
Microscopy Analysis ◽  
Copper Aluminum ◽  
Si Content ◽  
Scanning Electron

The present paper has discussed the growth inhibition role of silicon additions in Copper / Aluminum composite interface compounds. With different Si content of the aluminum composite sample after the comparison group, and interface with metallographic microscopy and by scanning electron microscopy analysis carried out and found that the Si incorporation can significantly inhibit the Copper / Aluminum interface compounds generated.

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