scholarly journals Application of Phytotests to Study of Environmental Safety of Biologicaly Synthetised Au and Au/ZnO Nanoparticles Using Tanacetum parthenium Extract

2021 ◽  
Author(s):  
Marcin Szymanski ◽  
Renata Dobrucka
Keyword(s):  
Ecological Impact ◽  
Environmental Safety ◽  
High Reactivity ◽  
Lepidium Sativum ◽  
Petroselinum Crispum ◽  
Force Microscopy ◽  
Tanacetum Parthenium ◽  
Transmission Electron ◽  
Linum Flavum

AbstractDue to their small sizes and high reactivity, nanoparticles have a completely different toxicity profile than larger particles, and it is difficult to predict their potential ecological impact. There is a need for broad ecotoxicological studies of nanomaterials in order to specify their environmental impact and ensure safe application of nanotechnology products. In this work, we have assessed the toxicity of Au and Au/ZnO metal nanoparticles obtained with the use of Tanacetum parthenium (herba) extract. The obtained nanoparticles were characterized by UV–Vis spectrophotometry (UV–VIS), Transmission electron microscopy (TEM), Atomic force microscopy (AFM), and Fourier transform infrared spectroscopy (FTIR). In order to assess the toxicity of biologically synthesized nanoparticles, we used seeds of various plants: Lepidium sativum, Linum flavum, Zea mays, Salvia hispanica-chia, Lupinus angustifolius, Petroselinum crispum subsp. Crispum, Beta vulgaris, Phaseolus vulgaris. The in vitro phytotests showed that gold nanoparticles at a specific range of concentrations for all plants stimulated their growth. The highest growth activity was exhibited by the solution at the concentration of 0.300 mg/ml towards corn (Aw ≈ − 135 ± 16) and flax (Aw ≈ − 44 ± 10). Only for parsley the IC50 was determined at 0.57 mg/ml, but solutions at the concentration of 0.030 to 0.150 mg/ml also stimulated plant growth. Au/ZnO had a toxic effect at all concentrations applied in the study.

Nanostructured biofunctionalized polyurethanes for applications in regenerative medicine

2012 ◽  
Vol 1417 ◽  
Author(s):  
Sebastian Kruss ◽  
Tobias Wolfram
Keyword(s):  
Electron Microscopy ◽  
Surface Engineering ◽  
Au Nanoparticles ◽  
Structural Features ◽  
Cellular Adhesion ◽  
Cellular Interactions ◽  
Force Microscopy ◽  
Transmission Electron ◽  
Adsorption Processes

ABSTRACTPolyurethane (PU) materials are used in a wide variety of implantable devices and technologies, e.g. stents, breast augmentation, nose surgery and bladder reconstruction. Despite the excellent chemical control for manufacturing bulk materials and the good biocompatibility, a major challenge remains interfacing of PU with biological environments. A chemically controlled surface engineering approach could improve desired protein adsorption processes and cellular interactions within different tissues, preventing uncontrolled events of the implant especially in early stages shortly after surgical procedures.To gain better control over the PU surfaces we polymerized different bulk PU materials and developed a transfer-nanolithography technique to deposit inorganic Au-nanoparticles with defined structural features on the PU surface. Different nanoparticle patterns were transferred and analyzed by scanning electron microscopy (SEM) and high-resolution transmission electron microscopy (HR-TEM). Topographical features of PU substrates were investigated by atomic force microscopy (AFM). Transferred Au-nanoparticles showed high stability on PU substrates even under extreme sonication conditions. In a final step, those nanoparticles were functionalized with peptides to facilitate cellular adhesion under physiologically relevant conditions. As proof of concept, rat embryonic fibroblast cells were cultured on a peptide functionalized PU interface and investigated by SEM.In conclusion, we developed a versatile method to prepare nanostructured and biofunctionalized PUs. These PUs showed good stability characteristics and in vitro biocompatibility in cell culture assays.

Microstructure, Properties and Biocompatibility of the Nitrided Ti-6Al-4V Alloy for Medical Application

2006 ◽  
Vol 513 ◽  
pp. 15-24 ◽  
Author(s):  
A. Czyrska-Filemonowicz ◽  
P.A. Buffat ◽  
E. Czarnowska ◽  
Tadeusz Wierzchoń
Keyword(s):  
Surface Topography ◽  
Bulk Material ◽  
Medical Application ◽  
Clear Correlation ◽  
Corrosion Properties ◽  
X Ray ◽  
Force Microscopy ◽  
Atomic Force ◽  
Transmission Electron

Investigation of the microstructure, properties and biocompatibility of the Ti-6Al-4V alloy nitrided under glow discharge was performed. The microstructural analyses were carried out using light microscopy, X-ray diffraction, analytical scanning and transmission electron microscopy. Phase identifications and chemical composition of the layer and bulk material (substrate) were determined by electron diffraction and energy dispersive X-ray spectrometry. Atomic force microscopy was applied for layer surface topography measurements. Microhardness and Young’s modulus measurements as well as frictional wear resistance and corrosion resistance tests were performed. The investigation revealed a clear correlation between the micro/nanostructure and surface topography of the layer with its micromechanical, tribological and corrosion properties. In-vitro examinations of biofilm and cell behaviour show that the nitrided Ti-6Al-4V alloy exhibits good biocompatibility.

scholarly journals Tunable Composition of Dynamic Non-Viral Vectors over the DNA Polyplex Formation and Nucleic Acid Transfection

Polymers ◽  
2019 ◽  
Vol 11 (8) ◽  
pp. 1313 ◽  
Author(s):  
Lilia Clima ◽  
Bogdan Florin Craciun ◽  
Gabriela Gavril ◽  
Mariana Pinteala
Keyword(s):  
Molecular Weight ◽  
Nucleic Acid ◽  
Viral Vectors ◽  
Viral Vector ◽  
Transfection Efficiency ◽  
Binding Capacity ◽  
Nucleic Acid Delivery ◽  
Force Microscopy ◽  
Transmission Electron

Polyethylene glycol (PEG) functionalization of non-viral vectors represents a powerful tool through the formation of an overall surface charge shielding ability, which is fundamental for efficient nucleic acid delivery systems. The degree of non-viral vector PEGylation and the molecular weight of utilized PEG is crucial since the excessive use of PEG units may lead to a considerable reduction of the DNA-binding capacity and, subsequently, in a reduction of in vitro transfection efficiency. Herein, we report a detailed study on a series of dynamic combinatorial frameworks (DCFs) containing PEGylated squalene, poly-(ethyleneglycol)-bis(3-aminopropyl) of different lengths, and branched low molecular weight polyethylenimine components, reversibly connected in hyperbranched structures, as efficient dynamic non-viral vectors. The obtained frameworks were capable of forming distinct supramolecular amphiphilic architectures, shown by transmission electron microscopy (TEM) and dynamic light scattering (DLS), with sizes and stability depending on the length of PEG units. The interaction of PEGylated DCFs with nucleic acids was investigated by agarose gel retardation assay and atomic force microscopy (AFM), while their transfection efficiency (using pCS2+MT-Luc DNA as a reporter gene) and cytotoxicity were evaluated in HeLa cells. In addition, the data on the influence of the poly-(ethyleneglycol)-bis(3-aminopropyl) length in composition of designed frameworks over transfection efficiency and tolerance in human cells were analyzed and compared.

scholarly journals Noncanonical type 2B von Willebrand disease associated with mutations in the VWF D′D3 and D4 domains

2020 ◽  
Vol 4 (14) ◽  
pp. 3405-3415 ◽  
Author(s):  
Monica Sacco ◽  
Stefano Lancellotti ◽  
Mattia Ferrarese ◽  
Francesco Bernardi ◽  
Mirko Pinotti ◽  
...  
Keyword(s):  
Ex Vivo ◽  
Von Willebrand Disease ◽  
Blood Analysis ◽  
Force Microscopy ◽  
Transmission Electron ◽  
Static Conditions ◽  
A1 Domain ◽  
Von Willebrand ◽  
In Cis

Abstract We observed a 55-year-old Italian man who presented with mucosal and cutaneous bleeding. Results of his blood analysis showed low levels of von Willebrand factor (VWF) antigen and VWF activity (both VWF ristocetin cofactor and VWF collagen binding), mild thrombocytopenia, increased ristocetin-induced platelet aggregation, and a deficiency of high-molecular-weight multimers, all typical phenotypic hallmarks of type 2B von Willebrand disease (VWD). The analysis of the VWF gene sequence revealed heterozygous in cis mutations: (1) c.2771G>A and (2) c.6532G>T substitutions in the exons 21 and 37, respectively. The first mutation causes the substitution of an Arg residue with a Gln at position 924, in the D′D3 domain. The second mutation causes an Ala to Ser substitution at position 2178 in the D4 domain. The patient’s daughter did not present the same fatherly mutations but showed only the heterozygous polymorphic c.3379C>T mutation in exon 25 of the VWF gene causing the p.P1127S substitution, inherited from her mother. The in vitro expression of the heterozygous in cis VWF mutant rVWFWT/rVWF924Q-2178S confirmed and recapitulated the ex vivo VWF findings. Molecular modeling showed that these in cis mutations stabilize a partially stretched and open conformation of the VWF monomer. Transmission electron microscopy and atomic force microscopy showed in the heterozygous recombinant form rVWFWT/rVWF924Q-2178S a stretched conformation, forming strings even under static conditions. Thus, the heterozygous in cis mutations 924Q/2178S promote conformational transitions in the VWF molecule, causing a type 2B–like VWD phenotype, despite the absence of typical mutations in the A1 domain of VWF.

scholarly journals A New Noncoding RNA Arranges Bacterial Chromosome Organization

mBio ◽  
2015 ◽  
Vol 6 (4) ◽  
Author(s):  
Zhong Qian ◽  
Mirjana Macvanin ◽  
Emilios K. Dimitriadis ◽  
Ximiao He ◽  
Victor Zhurkin ◽  
...  
Keyword(s):  
Dna Sequences ◽  
Noncoding Rna ◽  
Chromosome Conformation ◽  
Content Type ◽  
Force Microscopy ◽  
Transmission Electron ◽  
Bacterial Nucleoid ◽  
Dna Elements

ABSTRACTRepeated extragenic palindromes (REPs) in the enterobacterial genomes are usually composed of individual palindromic units separated by linker sequences. A total of 355 annotatedREPs are distributed along theEscherichia coligenome. RNA sequence (RNAseq) analysis showed that almost 80% of theREPs inE. coliare transcribed. The DNA sequence ofREP325showed that it is a cluster of six repeats, each with two palindromic units capable of forming cruciform structures in supercoiled DNA. Here, we report that components of theREP325element and at least one of its RNA products play a role in bacterial nucleoid DNA condensation. These RNA not only are present in the purified nucleoid but bind to the bacterial nucleoid-associated HU protein as revealed by RNA IP followed by microarray analysis (RIP-Chip) assays. Deletion ofREP325resulted in a dramatic increase of the nucleoid size as observed using transmission electron microscopy (TEM), and expression of one of theREP325RNAs, nucleoid-associated noncoding RNA 4 (naRNA4), from a plasmid restored the wild-type condensed structure. Independently, chromosome conformation capture (3C) analysis demonstrated physical connections among variousREPelements around the chromosome. These connections are dependent in some way upon the presence of HU and theREP325element; deletion of HU genes and/or theREP325element removed the connections. Finally, naRNA4 together with HU condensed DNAin vitroby connectingREP325or other DNA sequences that contain cruciform structures in a pairwise manner as observed by atomic force microscopy (AFM). On the basis of our results, we propose molecular models to explain connections of remote cruciform structures mediated by HU and naRNA4.IMPORTANCENucleoid organization in bacteria is being studied extensively, and several models have been proposed. However, the molecular nature of the structural organization is not well understood. Here we characterized the role of a novel nucleoid-associated noncoding RNA, naRNA4, in nucleoid structures bothin vivoandin vitro. We propose models to explain how naRNA4 together with nucleoid-associated protein HU connects remote DNA elements for nucleoid condensation. We present the first evidence of a noncoding RNA together with a nucleoid-associated protein directly condensing nucleoid DNA.

scholarly journals Scanning force microscopy of microtubules and polymorphic tubulin assemblies in air and in liquid

1995 ◽  
Vol 108 (3) ◽  
pp. 1063-1069
Author(s):  
W. Vater ◽  
W. Fritzsche ◽  
A. Schaper ◽  
K.J. Bohm ◽  
E. Unger ◽  
...  
Keyword(s):  
Scanning Force Microscopy ◽  
Force Microscopy ◽  
A Value ◽  
Transmission Electron ◽  
Associated Proteins ◽  
Scanning Force ◽  
Fibrous Morphology ◽  
Ultrathin Sections ◽  
20 Nm

We have investigated microtubules (MTs) and polymorphic assemblies, formed in vitro from isolated microtubule protein, by scanning force microscopy (SFM) in air and in liquid. Immobilization of MTs was achieved by placing a drop of the assembly solution on a polylysine-coated coverslip. After washing with taxol and air drying, the characteristic microtubular fibrous morphology appeared in the SFM. The MTs formed a network similar to that obtained by transmission electron microscopy (TEM). A height of approximately 9.5 nm for dried MTs was computed from the surface topography. Glutaraldehyde fixation of the MTs yielded higher structures (approximately 14 nm), which swelled to approximately 20 nm after rehydration, a value close to the MT diameter of approximately 25 nm determined from TEM images of ultrathin sections. The protofilament pattern of the MTs and surface attached MT-associated proteins were not apparent from SFM, although the height along the long axis of the MTs appeared slightly modulated. In addition to MTs, various polymorphic tubulin assemblies including ribbons, hoops and double-walled MTs were visualized by SFM.

scholarly journals Hydroxyapatite Formation Coexists with Amyloid-like Self-Assembly of Human Amelogenin

2020 ◽  
Vol 21 (8) ◽  
pp. 2946 ◽  
Author(s):  
Jing Zhang ◽  
Jian Wang ◽  
Chengwei Ma ◽  
Junxia Lu
Keyword(s):  
Self Assembly ◽  
Tooth Enamel ◽  
Protein Assembly ◽  
X Ray Diffraction ◽  
Force Microscopy ◽  
Atomic Force ◽  
Transmission Electron ◽  
Dynamic Components ◽  
The Right

Tooth enamel is formed in an extracellular environment. Amelogenin, the major component in the protein matrix of tooth enamel during the developing stage, could assemble into high molecular weight structures, regulating enamel formation. However, the molecular structure of amelogenin protein assembly at the functional state is still elusive. In this work, we found that amelogenin is able to induce calcium phosphate minerals into hydroxyapatite (HAP) structure in vitro at pH 6.0. Assessed using X-ray diffraction (XRD) and 31P solid-state NMR (SSNMR) evidence, the formed HAP mimics natural enamel closely. The structure of amelogenin protein assembly coexisting with the HAP was also studied using atomic force microscopy (AFM), transmission electron microscopy (TEM) and XRD, indicating the β-amyloid structure of the protein. SSNMR was proven to be an important tool in detecting both the rigid and dynamic components of the protein assembly in the sample, and the core sequence 18EVLTPLKWYQSI29 was identified as the major segment contributing to the β-sheet secondary structure. Our research suggests an amyloid structure may be an important factor in controlling HAP formation at the right pH conditions with the help of other structural components in the protein assembly.

scholarly journals Microscopic Techniques for the Analysis of Micro and Nanostructures of Biopolymers and Their Derivatives

Polymers ◽  
2020 ◽  
Vol 12 (3) ◽  
pp. 512 ◽  
Author(s):  
Abhilash Venkateshaiah ◽  
Vinod V.T. Padil ◽  
Malladi Nagalakshmaiah ◽  
Stanisław Waclawek ◽  
Miroslav Černík ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Decisive Role ◽  
Environmental Safety ◽  
Vital Role ◽  
Morphological Properties ◽  
Synthesis Of Nanoparticles ◽  
Force Microscopy ◽  
Atomic Force ◽  
Transmission Electron ◽  
Microscopic Techniques

Natural biopolymers, a class of materials extracted from renewable sources, is garnering interest due to growing concerns over environmental safety; biopolymers have the advantage of biocompatibility and biodegradability, an imperative requirement. The synthesis of nanoparticles and nanofibers from biopolymers provides a green platform relative to the conventional methods that use hazardous chemicals. However, it is challenging to characterize these nanoparticles and fibers due to the variation in size, shape, and morphology. In order to evaluate these properties, microscopic techniques such as optical microscopy, atomic force microscopy (AFM), and transmission electron microscopy (TEM) are essential. With the advent of new biopolymer systems, it is necessary to obtain insights into the fundamental structures of these systems to determine their structural, physical, and morphological properties, which play a vital role in defining their performance and applications. Microscopic techniques perform a decisive role in revealing intricate details, which assists in the appraisal of microstructure, surface morphology, chemical composition, and interfacial properties. This review highlights the significance of various microscopic techniques incorporating the literature details that help characterize biopolymers and their derivatives.

scholarly journals FRET-based Tau seeding assay does not represent prion-like templated assembly of Tau fibers

2020 ◽  
Author(s):  
Senthilvelrajan Kaniyappan ◽  
Katharina Tepper ◽  
Jacek Biernat ◽  
Ram Reddy Chandupatla ◽  
Sabrina Hübschmann ◽  
...  
Keyword(s):  
Recipient Cell ◽  
Pathological State ◽  
Amyloid Fibers ◽  
Force Microscopy ◽  
Atomic Force ◽  
Transmission Electron ◽  
Repeat Domain ◽  
Scanning Transmission ◽  
Tau Aggregation

AbstractTau aggregation into amyloid fibers based on the cross-beta structure is a hallmark of several Tauopathies, including Alzheimer Disease (AD). Trans-cellular propagation of Tau with pathological conformation has been suggested as a key disease mechanism. This is thought to cause the spreading of Tau pathology in AD by templated conversion of naive Tau in recipient cells into a pathological state, followed by assembly of pathological Tau fibers, similar to the mechanism proposed for prion pathogenesis. In cell cultures, the process is usually monitored by a FRET assay where the recipient cell expresses the Tau repeat domain (TauRD, with pro-aggregant mutation, e.g., ΔK280 or P301L, ∼13.5 kDa) fused to GFP-based FRET pairs (YFP or CFP, ∼28 kD). Since the diameter of the reporter GFP (∼3 nm) is ∼6.5 times larger than the β-strand distance (0.47nm), this points to a potential steric clash. Hence, we investigated the influence of GFP tagged (N- or C-terminally) TauRD and TauFL (full-length Tau) on their aggregation behavior in vitro. Using biophysical methods (light scattering, atomic force microscopy (AFM), and scanning-transmission electron microscopy (STEM)), we found that the assembly of TauRDΔK-GFP was severely inhibited, even in the presence of nucleation enhancers (heparin and/or pre-formed PHFs from TauRDΔK). Some rare fiber-like particles had a very different subunit packing from proper PHFs, as judged by STEM. The mass per length (MPL) values of TauRDΔK fibrils are equivalent to 4.45 molecules/nm, close to the expected value for a paired-helical fiber with 2 protofilaments and cross-β structure. By contrast, the elongated particles formed by TauRDΔK-GFP have MPL values around ∼2, less than half of the values expected for PHFs, indicating that the subunit packing is distinct. Thus, both kinetic and structural observations are incompatible with a model whereby external Tau can form a template for PHF assembly of Tau-GFP in recipient cells. As a consequence, the observed local increase of FRET in recipient cells must be caused by other signalling processes.

Maytansine-Induced Mitotic Arrest in Human Lymphoblasts

1977 ◽  
Vol 35 ◽  
pp. 460-461
Author(s):  
Tai-Te Chao ◽  
John Sullivan ◽  
Awtar Krishan
Keyword(s):  
Electron Microscopy ◽  
Cell Cycle ◽  
Transmission Electron Microscopy ◽  
Tubulin Polymerization ◽  
Vinca Alkaloids ◽  
Antimitotic Activity ◽  
Transmission Electron ◽  
Flow Microfluorometry ◽  
Brain Tubulin

Maytansine, a novel ansa macrolide (1), has potent anti-tumor and antimitotic activity (2, 3). It blocks cell cycle traverse in mitosis with resultant accumulation of metaphase cells (4). Inhibition of brain tubulin polymerization in vitro by maytansine has also been reported (3). The C-mitotic effect of this drug is similar to that of the well known Vinca- alkaloids, vinblastine and vincristine. This study was carried out to examine the effects of maytansine on the cell cycle traverse and the fine struc- I ture of human lymphoblasts.Log-phase cultures of CCRF-CEM human lymphoblasts were exposed to maytansine concentrations from 10-6 M to 10-10 M for 18 hrs. Aliquots of cells were removed for cell cycle analysis by flow microfluorometry (FMF) (5) and also processed for transmission electron microscopy (TEM). FMF analysis of cells treated with 10-8 M maytansine showed a reduction in the number of G1 cells and a corresponding build-up of cells with G2/M DNA content.

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