scholarly journals Iodine staining as a useful probe for distinguishing insulin amyloid polymorphs

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Takato Hiramatsu ◽  
Naoki Yamamoto ◽  
Seongmin Ha ◽  
Yuki Masuda ◽  
Mitsuru Yasuda ◽  
...  
Keyword(s):  
Amyloid Fibrils ◽  
Visible Region ◽  
Structural Diversity ◽  
Absorption Bands ◽  
Iodine Staining ◽  
Titration Curves ◽  
Wide Range ◽  
Diagnostic Samples ◽  
Resonance Raman Spectra ◽  
Deep Relationship

Abstract It is recently suggested that amyloid polymorphism, i.e., structural diversity of amyloid fibrils, has a deep relationship with pathology. However, its prompt recognition is almost halted due to insufficiency of analytical methods for detecting polymorphism of amyloid fibrils sensitively and quickly. Here, we propose that iodine staining, a historically known reaction that was firstly found by Virchow, can be used as a method for distinguishing amyloid polymorphs. When insulin fibrils were prepared and iodine-stained, they exhibited different colors depending on polymorphs. Each of the colors was inherited to daughter fibrils by seeding reactions. The colors were fundamentally represented as a sum of three absorption bands in visible region between 400 and 750 nm, and the bands showed different titration curves against iodine, suggesting that there are three specific iodine binding sites. The analysis of resonance Raman spectra and polarization microscope suggested that several polyiodide ions composed of I3− and/or I5− were formed on the grooves or the edges of β-sheets. It was concluded that the polyiodide species and conformations formed are sensitive to surface structure of amyloid fibrils, and the resultant differences in color will be useful for detecting polymorphism in a wide range of diagnostic samples.

scholarly journals Iodine staining as a useful probe for distinguishing amyloid fibril polymorphs

2020 ◽  
Author(s):  
Takato Hiramatsu ◽  
Naoki Yamamoto ◽  
Seongmin Ha ◽  
Yuki Masuda ◽  
Mitsuru Yasuda ◽  
...  
Keyword(s):  
Amyloid Fibrils ◽  
Visible Region ◽  
Structural Diversity ◽  
Absorption Bands ◽  
Iodine Staining ◽  
Titration Curves ◽  
Wide Range ◽  
Diagnostic Samples ◽  
Resonance Raman Spectra ◽  
Deep Relationship

ABSTRACTIt is recently suggested that amyloid polymorphism, i.e., structural diversity of amyloid fibrils, has a deep relationship with pathology. However, its prompt recognition is almost halted due to insufficiency of analytical methods for detecting polymorphism of amyloid fibrils sensitively and quickly. Here, we propose that iodine staining, a historically known reaction that was firstly found by Virchow, can be used as a method for distinguishing amyloid polymorphs. When insulin fibrils were prepared and iodine-stained, they exhibited different colors depending on polymorphs. Each of the colors was inherited to daughter fibrils by seeding reactions. The colors were fundamentally represented as a sum of three absorption bands in visible region between 400-750 nm, and the bands showed different titration curves against iodine, suggesting that there are three specific iodine binding sites. The analysis of resonance Raman spectra and polarization microscope suggested that several polyiodide ions composed of I3− and/or I5− were formed on the grooves or the edges of β-sheets. It was concluded that the polyiodide species and conformations formed are sensitive to surface structure of amyloid fibrils, and the resultant differences in color will be useful for detecting polymorphism in a wide range of diagnostic samples.

scholarly journals Multistep changes in amyloid structure that are induced by cross-seeding on a rugged energy landscape

2020 ◽  
Author(s):  
Keisuke Yuzu ◽  
Naoki Yamamoto ◽  
Masahiro Noji ◽  
Masatomo So ◽  
Yuji Goto ◽  
...  
Keyword(s):  
Structural Changes ◽  
Amyloid Fibrils ◽  
Energy Landscape ◽  
Structural Diversity ◽  
Bovine Insulin ◽  
Amyloid Formation ◽  
Heterologous Proteins ◽  
Iodine Staining ◽  
Dependent Growth ◽  
Value Decomposition

ABSTRACTAmyloid fibrils are aberrant protein aggregates associated with various amyloidoses and neurodegenerative diseases. It is recently indicated that structural diversity of amyloid fibrils often results in different pathological phenotypes including cytotoxicity and infectivity. The diverse structures are predicted to propagate by seed-dependent growth, which is one of the characteristic properties of amyloid fibrils. However, much remains unknown regarding how exactly the amyloid structures are inherited to subsequent generations by seeding reaction. Here, we investigated the behaviors of self- and cross-seeding of amyloid fibrils of human and bovine insulin in terms of thioflavin T fluorescence, morphology, secondary structure, and iodine staining. Insulin amyloid fibrils exhibited different structures depending on species, and each of which replicated in self-seeding. In contrast, gradual structural changes were observed in cross-seeding, and a new-type amyloid structure with distinct morphology and cytotoxicity was formed when human insulin was seeded with bovine insulin fibrils. Remarkably, iodine staining tracked changes in amyloid structure sensitively, and singular value decomposition (SVD) analysis of the UV-Vis absorption spectra of the fibril-bound iodine has revealed the presence of one or more intermediate metastable states during the structural changes. From these findings, we propose a propagation scheme with multistep structural changes in cross-seeding between two heterologous proteins, which is accounted for as a consequence of the rugged energy landscape of amyloid formation.

scholarly journals Preparation of ZnO-Zn2TiO4Sol Composite Films and Its Photocatalytic Activities

2013 ◽  
Vol 2013 ◽  
pp. 1-5 ◽  
Author(s):  
Xiujuan Qin ◽  
Li Cui ◽  
Guangjie Shao
Keyword(s):  
Methyl Orange ◽  
Photocatalytic Oxidation ◽  
Spectral Response ◽  
Sol Gel ◽  
Composite Films ◽  
Visible Region ◽  
Performance Testing ◽  
Structure Characterization ◽  
Semiconductor Oxides ◽  
Wide Range

Ti-doped ZnO sol-composite films were prepared on the glass substrate by the two-step sol-gel technique. X-ray diffraction, Uv-Vis spectrophotometer, and FS spectrum of composite films were used to help make structure characterization and optical performance testing. The results showed that the composite was a mixture of ZnO + Zn2TiO4. Because of synergistic effect of both semiconductor oxides, composite films had a wide range of spectral response in the visible region, and the absorption band edge was about 510 nm, and the Green Belt of composite films luminous significantly enhanced. Photocatalytic oxidation experiments showed that using the composite films treatment (16.5 ml, l0 mg/L methyl orange aqueous solution)/cm2, the decolorization rate of methyl-orange was 90% after 3 hours irradiation.

Peroxidase: a multifunctional enzyme in grapevines

2003 ◽  
Vol 30 (6) ◽  
pp. 577 ◽  
Author(s):  
Alfonso Ros Barceló ◽  
Federico Pomar ◽  
Matías López-Serrano ◽  
Maria Angeles Pedreño
Keyword(s):  
Cell Wall ◽  
Metabolic Regulation ◽  
Trichoderma Viride ◽  
Visible Spectrum ◽  
H2o2 Production ◽  
Class Iii ◽  
Absorption Bands ◽  
Peroxidase Isoenzyme ◽  
Wide Range ◽  
Uv C

Peroxidases are heme-containing enzymes that catalyse the one-electron oxidation of several substrates at the expense of H2O2. They are probably encoded by a large multigene family in grapevines, and therefore show a high degree of polymorphism. Grapevine peroxidases are glycoproteins of high thermal stability, whose molecular weight usually ranges from 35 to 45 kDa. Their visible spectrum shows absorption bands characteristic of high-spin class III peroxidases. Grapevine peroxidases are capable of accepting a wide range of natural compounds as substrates, such as the cell wall protein extensin, plant growth regulators such as IAA, and phenolics such as benzoic acids, stilbenes, flavonols, cinnamyl alcohols and anthocyanins. They are located in cell walls and vacuoles. These locations are in accordance with their key role in determining the final cell wall architecture, especially regarding lignin deposition and extensin insolubilization, and the turnover of vacuolar phenolic metabolites, a task that also forms part of the molecular program of disease resistance. Although peroxidase is a constitutive enzyme in grapevines, its levels are strongly modulated during plant cell development and in response to both biotic and abiotic environmental factors. To gain an insight into the metabolic regulation of peroxidase, several authors have studied how grapevine peroxidase and H2O2 levels change in response to a changing environment. Nevertheless, the results obtained are not always easy to interpret. Despite such difficulties, the response of the peroxidase–H2O2 system to both UV-C radiation and Trichoderma viride elicitors is worthy of study. Both UV-C and T. viride elicitors induce specific changes in peroxidase isoenzyme / H2O2 levels, which result in specific changes in grapevine physiology and metabolism. In the case of T. viride-elicited grapevine cells, they show a particular mechanism for H2O2 production, in which NADPH oxidase-like activities are apparently not involved. However, they offer a unique system whereby the metabolic regulation of peroxidase by H2O2, with all its cross-talks and downstream signals, may be elegantly dissected.

scholarly journals From Residues to Added-Value Bacterial Biopolymers as Nanomaterials for Biomedical Applications

Nanomaterials ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 1492
Author(s):  
Francisco G. Blanco ◽  
Natalia Hernández ◽  
Virginia Rivero-Buceta ◽  
Beatriz Maestro ◽  
Jesús M. Sanz ◽  
...  
Keyword(s):  
Biomedical Applications ◽  
Carbon Sources ◽  
Structural Diversity ◽  
Added Value ◽  
Nanoscale Systems ◽  
Chemical Structures ◽  
Wide Range ◽  
Peptide Functionalization ◽  
Metabolic Strategies ◽  
Drug Nanocarriers

Bacterial biopolymers are naturally occurring materials comprising a wide range of molecules with diverse chemical structures that can be produced from renewable sources following the principles of the circular economy. Over the last decades, they have gained substantial interest in the biomedical field as drug nanocarriers, implantable material coatings, and tissue-regeneration scaffolds or membranes due to their inherent biocompatibility, biodegradability into nonhazardous disintegration products, and their mechanical properties, which are similar to those of human tissues. The present review focuses upon three technologically advanced bacterial biopolymers, namely, bacterial cellulose (BC), polyhydroxyalkanoates (PHA), and γ-polyglutamic acid (PGA), as models of different carbon-backbone structures (polysaccharides, polyesters, and polyamides) produced by bacteria that are suitable for biomedical applications in nanoscale systems. This selection models evidence of the wide versatility of microorganisms to generate biopolymers by diverse metabolic strategies. We highlight the suitability for applied sustainable bioprocesses for the production of BC, PHA, and PGA based on renewable carbon sources and the singularity of each process driven by bacterial machinery. The inherent properties of each polymer can be fine-tuned by means of chemical and biotechnological approaches, such as metabolic engineering and peptide functionalization, to further expand their structural diversity and their applicability as nanomaterials in biomedicine.

Heparin remodels the microtubule-binding repeat R3 of Tau protein towards fibril-prone conformations

2021 ◽  
Author(s):  
Xuewei Dong ◽  
Ruxi Qi ◽  
Qin Qiao ◽  
Xuhua Li ◽  
Fangying Li ◽  
...  
Keyword(s):  
Neurodegenerative Diseases ◽  
Tau Protein ◽  
Amyloid Fibrils ◽  
Microtubule Binding ◽  
Wide Range

Abnormal aggregation of proteins into pathological amyloid fibrils are implicated in a wide range of devastating human neurodegenerative diseases. Intracellular fibrillary inclusions formed by Tau protein are characterized as the...

Transition Moments of Visible Region Absorption Bands oftrans(Cl)-Triammineaquadichlorocobalt(III) Chloride

2002 ◽  
Vol 75 (11) ◽  
pp. 2407-2413 ◽  
Author(s):  
Yoshihiro Mitsutsuka ◽  
Nobuhiko Nawa ◽  
Shuji Yoshizawa ◽  
Hirofumi Yajima ◽  
Keiji Iriyama ◽  
...  
Keyword(s):  
Visible Region ◽  
Absorption Bands ◽  
Transition Moments

scholarly journals A III B VI PHOTOVOLTAIC RECEPTORS FOR EXPERIMENTAL DETERMINATION OF CARBON COMPOUNDS IN ATMOSPHERE

2016 ◽  
Vol 19 (3) ◽  
Author(s):  
IULIANA CARAMAN ◽  
IGOR EVTODIEV ◽  
OXANA RACOVEŢ ◽  
MARIUS STAMATE
Keyword(s):  
Electric Fields ◽  
Full Range ◽  
Absorption Bands ◽  
Gaseous State ◽  
Wide Range ◽  
Carbon Compounds ◽  
Strong Electric Fields ◽  
Qualitative Measurements ◽  
Semiconductor Type

<p><span lang="EN-US">This paper examines the prospects of using semiconductor layered A<span class="apple-converted-space"> </span><sup>III</sup><span class="apple-converted-space"> </span>B<span class="apple-converted-space"> </span><sup>VI</sup><span class="apple-converted-space"> type -</span> photovoltaic cells<span class="apple-converted-space"> </span>and the photoresis<span class="apple-converted-space">tors</span> as receptors<span class="apple-converted-space"> </span>for quantitative and qualitative measurements of carbon oxides. Carbon compounds in gaseous state form absorption bands of<span class="apple-converted-space"> </span>electromagnetic<span class="apple-converted-space"> </span>radiation in a wide range of spectrum (200 ÷ 100 000) cm<sup>-1</sup>.<span class="apple-converted-space"> </span>The light absorbed<span class="apple-converted-space"> </span>or emitted<span class="apple-converted-space"> </span>in these bands <span class="apple-converted-space">at the</span> excitations with ionizing radiation (X, γ) or strong electric fields contain direct information about the<span class="apple-converted-space"> </span>concentration of these molecules.  The frequencies that<span class="apple-converted-space"> </span>correspond to maxima of these bands are characteristic parameters of absorbing molecules. Fundamental absorption bands of CO, CO<span class="apple-converted-space"> </span><sub>2</sub> and NC have the edge of band at the border of ultraviolet-vacuum, while the emission bands <em>d</em> cover their full range of wave numbers from 45000 cm<sup>-1 </sup>to 10000 cm<sup>-1</sup>. Two types of radiation receptors from lamellar semiconductor type A<sup>III</sup>B<sup>VI</sup><span class="apple-converted-space"> </span>photosensitive in this spectral range are studied.</span></p>

Room-Temperature Ceramic Nanocoating Using Nanosheet Deposition Technique

2013 ◽  
Vol 2013 (CICMT) ◽  
pp. 000014-000018 ◽  
Author(s):  
M. Osada ◽  
T. Sasaki
Keyword(s):  
Room Temperature ◽  
Organic Molecules ◽  
Structural Diversity ◽  
Layer By Layer ◽  
Precise Control ◽  
Langmuir Blodgett ◽  
Wide Range ◽  
Potential Applications ◽  
Layer Assembly ◽  
Selection Of

We present a novel procedure for ceramic nanocoating using oxide nanosheet as a building block. A variety of oxide nanosheets (such as Ti1−δO2, MnO2 and perovsites) were synthesized by delaminating appropriate layered precursors into their molecular single sheets. These nanosheets are exceptionally rich in both structural diversity and electronic properties, with potential applications including conductors, semiconductors, insulators, and ferromagnets. Another attractive aspect is that nanosheets can be organized into various nanoarchitectures by applying solution-based synthetic techniques involving electrostatic layer-by-layer assembly and Langmuir-Blodgett deposition. It is even possible to tailor superlattice assemblies, incorporating into the nanosheet galleries with a wide range of materials such as organic molecules, polymers, and inorganic/metal nanoparticles. Sophisticated functionalities or paper-like devices can be designed through the selection of nanosheets and combining materials, and precise control over their arrangement at the molecular scale.

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