scholarly journals Structure and Function of Trypsin-Loaded Fibrinolytic Liposomes

2017 ◽  
Vol 2017 ◽  
pp. 1-10 ◽  
Author(s):  
Anna Tanka-Salamon ◽  
Attila Bóta ◽  
András Wacha ◽  
Judith Mihály ◽  
Miklós Lovas ◽  
...  
Keyword(s):  
Freeze Fracture ◽  
Product Concentration ◽  
Plasma Clot ◽  
Dynamic Conditions ◽  
X Ray Scattering ◽  
Transmission Electron ◽  
Ft Ir ◽  
And Function ◽  
Targeted Release ◽  
Fibrinolytic Action

Protease encapsulation and its targeted release in thrombi may contribute to the reduction of haemorrhagic complications of thrombolysis. We aimed to prepare sterically stabilized trypsin-loaded liposomes (SSLT) and characterize their structure and fibrinolytic efficiency. Hydrogenated soybean phosphatidylcholine-basedSSLTwere prepared and their structure was studied by transmission electron microscopy combined with freeze fracture (FF-TEM), Fourier transform infrared spectroscopy (FT-IR), and small-angle X-ray scattering (SAXS). Fibrinolytic activity was examined at 45, 37, or 24°C on fibrin or plasma clots with turbidimetric and permeation-driven lysis assays. Trypsin was shown to be attached to the inner surface of vesicles (SAXS and FF-TEM) close to the lipid hydrophilic/hydrophobic interface (FT-IR). The thermosensitivity ofSSLTwas evidenced by enhanced fibrinolysis at 45°C: time to reduce the maximal turbidity to 20% decreased by 8.6% compared to 37°C and fibrin degradation product concentration in the permeation lysis assay was 2-fold to 5-fold higher than that at 24°C.SSLTexerted its fibrinolytic action on fibrin clots under both static and dynamic conditions, whereas plasma clot dissolution was observed only in the permeation-driven assay. The improved fibrinolytic efficiency ofSSLTunder dynamic conditions suggests that they may serve as a novel therapeutic candidate for dissolution of intravascular thrombi, which are typically exposed to permeation forces.

scholarly journals Nature-Inspired Polymerization of Quercetin to Produce Antioxidant Nanoparticles with Controlled Size and Skin Tone-Matching Colors

Molecules ◽  
2019 ◽  
Vol 24 (21) ◽  
pp. 3815 ◽  
Author(s):  
Suhair Sunoqrot ◽  
Eveen Al-Shalabi ◽  
Lina Hasan Ibrahim ◽  
Hiba Zalloum
Keyword(s):  
Self Assembly ◽  
Biomedical Applications ◽  
Radical Scavenging Activity ◽  
Radical Scavenging ◽  
Skin Tone ◽  
Plant Polyphenols ◽  
Transmission Electron ◽  
Ft Ir ◽  
And Function ◽  
First Time

Plant polyphenols have received considerable attention in recent years due to their ability to undergo oxidation-triggered self-polymerization, forming biocompatible versatile coatings and templated nanoparticles (NPs) that can be leveraged for a variety of biomedical applications. Here we show for the first time that untemplated NPs can be conveniently synthesized from the abundant plant polyphenol quercetin (QCT) simply by incubation with an oxidizing agent in a universal organic solvent, followed by self-assembly upon gradual addition of water. The process yielded NPs of around 180–200 nm in size with a range of colors that resembled light to medium-brown skin tones. The NPs were characterized by UV-Vis, FT-IR, and 1H-NMR spectroscopy and by dynamic light scattering and transmission electron microscopy to understand their physicochemical properties. Antioxidant and cell viability assays were also conducted to demonstrate the NPs’ free-radical scavenging activity and biocompatibility, altogether providing valuable insights into the structure and function of this emerging class of nanomaterials to guide future biomedical applications.

Scanning electron microscopy of the septal pore cap of the basidiomycete Schizophyllum commune

1994 ◽  
Vol 40 (10) ◽  
pp. 879-883 ◽  
Author(s):  
Wally H. Müller ◽  
Adriaan C. van Aelst ◽  
Theo P. van der Krift ◽  
Teun Boekhout
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Endoplasmic Reticulum ◽  
Schizophyllum Commune ◽  
Freeze Fracture ◽  
Freeze Substitution ◽  
Transmission Electron ◽  
And Function ◽  
Tubular Endoplasmic Reticulum ◽  
Scanning Electron

As part of a comparative study of the structure and function of pore structures in heterobasidiomycetous yeasts, dikaryotic hyphae of Schizophyllum commune were subjected to chemical fixation, freeze fracturing, maceration, and freeze substitution, and were subsequently prepared for scanning electron microscopy. The interior of the hyphal cell was visualized and revealed the perforated septal pore cap or parenthesome, mitochondria, vacuoles, and tubular endoplasmic reticulum. The septal pore cap showed connections with tubular endoplasmic reticulum. This tubular endoplasmic reticulum covered the dolipore septal surface. The results presented here complement and extend the ultrastructural image of the septal pore cap obtained from transmission electron micrographs.Key words: septal pore cap, Schizophyllum commune, freeze fracture, maceration, scanning electron microscopy.

Cryomicroscopy of multiphase latices

1991 ◽  
Vol 49 ◽  
pp. 1060-1061
Author(s):  
O. L. Shaffer ◽  
M.S. El-Aasser ◽  
C. L. Zhao ◽  
M. A. Winnik ◽  
R. R. Shivers
Keyword(s):  
Electron Microscopy ◽  
Radiation Damage ◽  
Freeze Fracture ◽  
Particle Morphology ◽  
Second Stage ◽  
Transmission Electron ◽  
Important Approach ◽  
Carbon Coated ◽  
Preparation Techniques

Transmission electron microscopy is an important approach to the characterization of the morphology of multiphase latices. Various sample preparation techniques have been applied to multiphase latices such as OsO4, RuO4 and CsOH stains to distinguish the polymer phases or domains. Radiation damage by an electron beam of latices imbedded in ice has also been used as a technique to study particle morphology. Further studies have been developed in the use of freeze-fracture and the effect of differential radiation damage at liquid nitrogen temperatures of the latex particles embedded in ice and not embedded.Two different series of two-stage latices were prepared with (1) a poly(methyl methacrylate) (PMMA) seed and poly(styrene) (PS) second stage; (2) a PS seed and PMMA second stage. Both series have varying amounts of second-stage monomer which was added to the seed latex semicontinuously. A drop of diluted latex was placed on a 200-mesh Formvar-carbon coated copper grid.

Techniques for cryoultramicrotomy of propane jet frozen biological samples

1986 ◽  
Vol 44 ◽  
pp. 260-261
Author(s):  
B. Craig ◽  
L. Hawkey ◽  
A. LeFurgey
Keyword(s):  
Freeze Fracture ◽  
Freeze Substitution ◽  
Heart Cells ◽  
Crystal Formation ◽  
X Ray ◽  
Transmission Electron ◽  
Scanning Transmission ◽  
Chick Heart ◽  
Embryonic Chick Heart ◽  
A New Technique

Ultra-rapid freezing followed by cryoultramicrotomy is essential for the preservation of diffusible elements in situ within cells prior to scanning transmission electron microscopy and quantitative energy dispersive x-ray microanalysis. For cells or tissue fragments in suspension and for monolayer cell cultures, propane jet freezing provides cooling rates greater than 30,000°C/sec with regions up to 40μm in thickness free of significant ice crystal formation. While this method of freezing has frequently been applied prior to freeze fracture or freeze substitution, it has not been widely utilized prior to cryoultramicrotomy and subsequent x-ray microanalytical studies. This report describes methods devised in our laboratory for cryosectioning of propane jet frozen kidney proximal tubule suspensions and cultured embryonic chick heart cells, in particular a new technique for mounting frozen suspension specimens for sectioning. The techniques utilize the same specimen supports and sample holders as those used for freeze fracture and freeze substitution and should be generally applicable to any cell suspension or culture preparation.

Three-Dimensional Immunoelectron Microscopy of Yeast Cells by a New High-Resolution Replica Method

1985 ◽  
Vol 43 ◽  
pp. 562-563
Author(s):  
Hirano T. ◽  
M. Yamaguchi ◽  
M. Hayashi ◽  
Y. Sekiguchi ◽  
A. Tanaka
Keyword(s):  
High Resolution ◽  
Plasma Polymerization ◽  
Three Dimensional ◽  
Freeze Fracture ◽  
Replica Method ◽  
Yeast Cells ◽  
Dynamic Aspect ◽  
Replica Technique ◽  
Gaseous Hydrocarbon ◽  
Transmission Electron

A plasma polymerization film replica method is a new high resolution replica technique devised by Tanaka et al. in 1978. It has been developed for investigation of the three dimensional ultrastructure in biological or nonbiological specimens with the transmission electron microscope. This method is based on direct observation of the single-stage replica film, which was obtained by directly coating on the specimen surface. A plasma polymerization film was deposited by gaseous hydrocarbon monomer in a glow discharge.The present study further developed the freeze fracture method by means of a plasma polymerization film produces a three dimensional replica of chemically untreated cells and provides a clear evidence of fine structure of the yeast plasma membrane, especially the dynamic aspect of the structure of invagination (Figure 1).

Structure of contact sites between the outer and inner mitochondrial membranes investigated by HVEM tomography

1996 ◽  
Vol 54 ◽  
pp. 966-967
Author(s):  
C.A. Mannella ◽  
K.F. Buttle ◽  
K.A. O‘Farrell ◽  
A. Leith ◽  
M. Marko
Keyword(s):  
Liver Mitochondrion ◽  
Adenine Nucleotide ◽  
Protein Complexes ◽  
Mitochondrial Membranes ◽  
Electron Microscopic ◽  
Contact Sites ◽  
Transmission Electron ◽  
Precursor Proteins ◽  
Membrane Contacts ◽  
And Function

Early transmission electron microscopy of plastic-embedded, thin-sectioned mitochondria indicated that there are numerous junctions between the outer and inner membranes of this organelle. More recent studies have suggested that the mitochondrial membrane contacts may be the site of protein complexes engaged in specialized functions, e.g., import of mitochondrial precursor proteins, adenine nucleotide channeling, and even intermembrane signalling. It has been suggested that the intermembrane contacts may be sites of membrane fusion involving non-bilayer lipid domains in the two membranes. However, despite growing interest in the nature and function of intramitochondrial contact sites, little is known about their structure.We are using electron microscopic tomography with the Albany HVEM to determine the internal organization of mitochondria. We have reconstructed a 0.6-μm section through an isolated, plasticembedded rat-liver mitochondrion by combining 123 projections collected by tilting (+/- 70°) around two perpendicular tilt axes. The resulting 3-D image has confirmed the basic inner-membrane organization inferred from lower-resolution reconstructions obtained from single-axis tomography.

A Cross-Method Comparison of Sub-10 nm Nanoparticle Size Distribution

2019 ◽  
Author(s):  
Ye Yang ◽  
Suiyang Liao ◽  
Zhi Luo ◽  
Runzhang Qi ◽  
Niamh Mac Fhionnlaoich ◽  
...  
Keyword(s):  
Size Distribution ◽  
Analytical Ultracentrifugation ◽  
Statistical Significance ◽  
Method Comparison ◽  
Size Determination ◽  
Size Dependent ◽  
X Ray Scattering ◽  
Transmission Electron ◽  
Gold Nps ◽  
Reliable Representation

Accurate nanoparticle (NP) size determination is essential across research domains, with many functions in nanoscience and biomedical research being size-dependent. Although transmission electron microscopy (TEM) is capable of resolving a single NP down to the sub-nm scale, the reliable representation of entire populations is plagued by challenges in providing statistical significance, predominantly due to limited sample counts, suboptimal preparation procedures and operator bias during image acquisition and analysis. Meanwhile alternative techniques exist, but reliable implementation requires a detailed understanding of appendant limitations. Herein, conventional TEM is compared to the size determination of sub-10 nm gold NPs in solution by small-angle X-ray scattering and analytical ultracentrifugation. Form-free Monte Carlo fitting of scattering profiles offers access to a direct representation of the core size distribution while ultracentrifugation sedimentation velocity analysis provides information of the hydrodynamic size distribution. We report a comparison of these three methods in determining the size of quasi-monodisperse, polydisperse and bimodal gold nanoparticles of 2 – 7 nm and discuss advantages and limitations of each technique.

scholarly journals Pd Nanoparticles Stabilized on the Cross-Linked Melamine-Based SBA-15 as a Catalyst for the Mizoroki–Heck Reaction

2021 ◽  
Author(s):  
Ayat Nuri ◽  
Abolfazl Bezaatpour ◽  
Mandana Amiri ◽  
Nemanja Vucetic ◽  
Jyri-Pekka Mikkola ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Inductively Coupled Plasma ◽  
High Surface ◽  
High Surface Area ◽  
Coupling Reaction ◽  
Pd Nanoparticles ◽  
Significant Activity ◽  
Inductively Coupled ◽  
Transmission Electron ◽  
Ft Ir

AbstractMesoporous SBA-15 silicate with a high surface area was prepared by a hydrothermal method, successively modified by organic melamine ligands and then used for deposition of Pd nanoparticles onto it. The synthesized materials were characterized with infrared spectroscopy (FT-IR), thermogravimetric analysis (TGA), nitrogen physisorption, scanning electron microscopy (SEM) coupled with energy dispersive X-ray analysis (EDX), transmission electron microscopy (TEM), nuclear magnetic resonance (NMR) and inductively coupled plasma (ICP-OES). The catalyst was effectively used in the Mizoroki–Heck coupling reaction of various reactants in the presence of an organic base giving the desired products in a short reaction time and with small catalysts loadings. The reaction parameters such as the base type, amounts of catalyst, solvents, and the temperature were optimized. The catalyst was easily recovered and reused at least seven times without significant activity losses. Graphic Abstract

scholarly journals Mice with cleavage-resistant N-cadherin exhibit synapse anomaly in the hippocampus and outperformance in spatial learning tasks

2021 ◽  
Vol 14 (1) ◽  
Author(s):  
M. Asada-Utsugi ◽  
K. Uemura ◽  
M. Kubota ◽  
Y. Noda ◽  
Y. Tashiro ◽  
...  
Keyword(s):  
Memory Function ◽  
Three Dimensional ◽  
Excitatory Synapses ◽  
Missense Mutations ◽  
Glutamatergic Synapses ◽  
Learning Tasks ◽  
Transmission Electron ◽  
Nmdar Activation ◽  
And Function

AbstractN-cadherin is a homophilic cell adhesion molecule that stabilizes excitatory synapses, by connecting pre- and post-synaptic termini. Upon NMDA receptor (NMDAR) activation by glutamate, membrane-proximal domains of N-cadherin are cleaved serially by a-disintegrin-and-metalloprotease 10 (ADAM10) and then presenilin 1(PS1, catalytic subunit of the γ-secretase complex). To assess the physiological significance of the initial N-cadherin cleavage, we engineer the mouse genome to create a knock-in allele with tandem missense mutations in the mouse N-cadherin/Cadherin-2 gene (Cdh2R714G, I715D, or GD) that confers resistance on proteolysis by ADAM10 (GD mice). GD mice showed a better performance in the radial maze test, with significantly less revisiting errors after intervals of 30 and 300 s than WT, and a tendency for enhanced freezing in fear conditioning. Interestingly, GD mice reveal higher complexity in the tufts of thorny excrescence in the CA3 region of the hippocampus. Fine morphometry with serial section transmission electron microscopy (ssTEM) and three-dimensional (3D) reconstruction reveals significantly higher synaptic density, significantly smaller PSD area, and normal dendritic spine volume in GD mice. This knock-in mouse has provided in vivo evidence that ADAM10-mediated cleavage is a critical step in N-cadherin shedding and degradation and involved in the structure and function of glutamatergic synapses, which affect the memory function.

scholarly journals A Facile Urea-Assisted Thermal Decomposition Process of TiO2 Nanoparticles and Their Photocatalytic Activity

Coatings ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 165
Author(s):  
Sandip Madhukar Deshmukh ◽  
Mohaseen S. Tamboli ◽  
Hamid Shaikh ◽  
Santosh B. Babar ◽  
Dipak P. Hiwarale ◽  
...  
Keyword(s):  
Thermal Decomposition ◽  
Photocatalytic Activity ◽  
Tio2 Nanoparticles ◽  
Large Scale ◽  
Ultra Violet ◽  
Tio2 Nps ◽  
Transmission Electron ◽  
Structures And Properties ◽  
Ft Ir ◽  
Large Scale Synthesis

In the present work, we have reported a facile and large-scale synthesis of TiO2 nanoparticles (NPs) through urea-assisted thermal decomposition of titanium oxysulphate. We have successfully synthesized TiO2 NPs by using this effective route with different weight ratios of titanium oxysulphate: urea. The structures and properties of TiO2 NPs were confirmed by scanning electron microscope) (SEM), transmission electron microscopy (TEM), thermogravimetric analysis (TGA), fourier transform infrared spectroscopy (FT-IR), ultra violet–visible spectroscopy (UV-vis), and photoluminescence (Pl) techniques. XRD demonstrated that TiO2 NPs holds of anatase crystal phase with crystallizing size 14–19 nm even after heating at 600 °C. TGA, SEM, and TEM images reveal urea’s role, which controls the size, morphology, and aggregation of TiO2 NPs during the thermal decomposition. These TiO2 NPs were employed for photodegradation of Methyl Orange (MO) in the presence of ultraviolet (UV) radiation. An interesting find was that the TiO2 NPs exhibited better photocatalytic activity and excellent recycling stability over several photodegradation cycles. Furthermore, the present method has a great perspective to be used as an efficient method for large-scale synthesis of TiO2 NPs.

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