Influence of Lysozyme on the Biomimetic Growth of Silica Tubes in Porous Membranes

2007 ◽  
Vol 1008 ◽  
Author(s):  
Clémentine Gautier ◽  
Rémi Courson ◽  
Pascal Jean Lopez ◽  
Jacques Livage ◽  
Thibaud Coradin
Keyword(s):  
Porous Membranes ◽  
Shell Formation ◽  
Core Particle ◽  
Biomimetic Models ◽  
Membrane Pores ◽  
The Core ◽  
Core Shell Structure ◽  
Poly Carbonate ◽  
Tube Shell

AbstractPore channels of poly-carbonate membranes were recently used as biomimetic models to study the effect of confinement on silicate condensation, leading to the formation of silica tubes exhibiting a core-shell structure. In this work, we pre-immobilized lysozyme on the membrane pores, inducing the modification of the tube shell formation process, and variation in core particle size. These data strengthen previous assumptions on the role of interfacial interactions on the growth of the tube shell and indicate that such interactions also influence the core particle formation. Such approach therefore seems suitable to mimic the formation of silica/protein multilayers as found in several biomineralizing organisms

The role of diffusion behavior on the formation and evolution of the core‐shell structure in BaTiO 3 ‐based ceramics

2019 ◽  
Vol 103 (1) ◽  
pp. 304-314 ◽  
Author(s):  
Cheng Chen ◽  
Hua Hao ◽  
Jingjing Cui ◽  
Cong Yu ◽  
Yingfei Tang ◽  
...  
Keyword(s):  
Shell Structure ◽  
Core Shell ◽  
Diffusion Behavior ◽  
The Core ◽  
Formation And Evolution ◽  
Core Shell Structure

scholarly journals The Proteasome Activators Blm10/PA200 Enhance the Proteasomal Degradation of N-Terminal Huntingtin

Biomolecules ◽  
2020 ◽  
Vol 10 (11) ◽  
pp. 1581
Author(s):  
Azzam Aladdin ◽  
Yanhua Yao ◽  
Ciyu Yang ◽  
Günther Kahlert ◽  
Marvi Ghani ◽  
...  
Keyword(s):  
Proteasomal Degradation ◽  
Peptidase Activity ◽  
Aggregate Formation ◽  
Core Particle ◽  
Independent Manner ◽  
Cellular Toxicity ◽  
The Core ◽  
Unstructured Proteins

The Blm10/PA200 family of proteasome activators modulates the peptidase activity of the core particle (20S CP). They participate in opening the 20S CP gate, thus facilitating the degradation of unstructured proteins such as tau and Dnm1 in a ubiquitin- and ATP-independent manner. Furthermore, PA200 also participates in the degradation of acetylated histones. In our study, we use a combination of yeast and human cell systems to investigate the role of Blm10/PA200 in the degradation of N-terminal Huntingtin fragments (N-Htt). We demonstrate that the human PA200 binds to N-Htt. The loss of Blm10 in yeast or PA200 in human cells results in increased mutant N-Htt aggregate formation and elevated cellular toxicity. Furthermore, Blm10 in vitro accelerates the proteasomal degradation of soluble N-Htt. Collectively, our data suggest N-Htt as a new substrate for Blm10/PA200-proteasomes and point to new approaches in Huntington’s disease (HD) research.

scholarly journals Silica/polymer core–shell particles prepared via soap-free emulsion polymerization

e-Polymers ◽  
2020 ◽  
Vol 20 (1) ◽  
pp. 254-261
Author(s):  
Mina Ishihara ◽  
Tomofumi Kaeda ◽  
Takashi Sasaki
Keyword(s):  
Emulsion Polymerization ◽  
Radical Polymerization ◽  
Shell Structure ◽  
Cross Linking ◽  
Core Shell ◽  
Shell Formation ◽  
The Core ◽  
Core Shell Structure ◽  
Soap Free Emulsion Polymerization ◽  
Shell Particles

AbstractIn this study, core–shell particles were prepared as a hybrid material, in which a thin polymer shell was formed on the surface of the SiO2 sphere particles. The core–shell structure was successfully achieved without adding a surfactant via simple free-radical polymerization (soap-free emulsion polymerization) for various monomers of styrene, methyl methacrylate (MMA), and their derivatives. MMA formed thin homogeneous shells of polymer (PMMA) less than 100 nm in thickness with complete surface coverage and a very smooth shell surface. The obtained shell morphology strongly depended on the monomers, which suggests different shell formation mechanisms with respect to the monomers. It was found that the cross-linking monomer 1,4-divinylbenzene tends to promote shell formation, and the cross-linking reaction may stabilize the core–shell structure throughout radical polymerization. It should also be noted that the present method produced a considerable amount of pure polymer besides the core–shell particles. The glass transition temperatures of the obtained polymer shells were higher than those of the corresponding bulk materials. This result suggests strong interactions at the core–shell interface.

scholarly journals Control of Spectral Shift of Plasmon Resonance of Ag-PVP Nanocomposite By Varying The PVP Shell Thickness In Core-Shell Structure

2021 ◽  
Author(s):  
Dilip Sao ◽  
Probodh Kumar Kuiri ◽  
Rajib Nath
Keyword(s):  
Plasmon Resonance ◽  
Shell Structure ◽  
Crucial Role ◽  
Shell Thickness ◽  
Synthesis Process ◽  
Core Shell ◽  
Ag Nps ◽  
The Core ◽  
Core Shell Structure

Abstract Metal-polymer nanocomposite materials have interesting physical, chemical, and optical properties which were highly utilized in electronic, optical,and biomedical applications. Here, we have experimentally and theoretically studied the crucial role of polymer Polyvinylpyrrolidone (PVP) on the localized surface plasmon resonance (LSPR) spectra of silver (Ag) nanoparticles (NPs). In this work, we have synthesized PVP stabilized Ag NPs in Ethelene Glycol (EG) medium and observed a large blueshift (20 nm)of LSPR peak and tunable plasmonic properties of PVP coated Ag NPs by only varying the concentration of PVP. A reduction of Ag NP size from 13 nm to 5 nm with the increase in PVP concentration from 0.125 mM to 3 mM is seen. We found that the observed large blueshift of the LSPR bands with the varying in PVP concentration is not just due to the reduced Ag NP size but due to the combined effect of thickness of the PVP shell and radius of the Ag NP core. The polymer PVP used in the synthesis process of Ag NPs plays role of a surface modifier and forms a protective shell/layer surrounding the (core) particle. This is supported by the theoretical optical absorption data obtained from a modified effective medium theory. To accommodate such a large blueshift of the LSPR bands we have considered the Ag-PVP core-shell structure. The LSPR peak shift in the core-shell nanostructure is well accommodated by varying the effective shell thickness of PVP while taking the core size of Ag NPs as measured experimentally for each case. This clearly indicates that the observed large blueshift of SPR band of Ag NPs cannot be justified by considering the decrease in Ag NP size alone. It is also confirmed that the shell thickness of PVP plays a crucial role in explaining the blueshift of the SPR band of Ag NPs. This study can help to understand the optical response especially plasmonic properties of other metal NPs coated with organic polymers.

The Effect of Exogenous Fluoride on the Calcium PUMP, Ciliary Activity, and Shell Formation of the Fingernail Clam, Musculium Transversum

1982 ◽  
Vol 40 ◽  
pp. 58-59
Author(s):  
Anthony Paparo ◽  
Judy A. Murphy ◽  
Robert Dean
Keyword(s):  
Mississippi River ◽  
Calcium Pump ◽  
Bottom Fauna ◽  
Ciliary Activity ◽  
Shell Formation ◽  
Middle Reach ◽  
Shell Matrix ◽  
Fingernail Clams ◽  
Ca Carbonate

In the mid-1950's, fingernail clams virtually disappeared from a 100-mile section of the IL River, a tributary of the Mississippi River, due to unknown causes. A survey of the bottom fauna of the IL River in 1979, revealed that the clams were still absent from the middle reach of the River, where they had been abundant prior to the die-off in the 1950's. Some factor(s) in the River currently prevent the clams from recolonizing areas where they were formerly abundant. Recently, clams exposed to fluoride developed abnormal grooves in the shell matrix. Fluorides are known to be protoplasmic poisons removing essential body calcium by precipitation. Since the shell consists primarily of Ca carbonate, this investigation examines the possible role of fluoride on shell formation and the poisoning of the Ca pump which can directly inhibit lateral ciliary activity on the gill.

Silicon Substitution for Calcium in the Shell of the Fingernail Clam, Musculium Transversum Studied By X-Ray Analysis

1980 ◽  
Vol 38 ◽  
pp. 560-561
Author(s):  
Judith A. Murphy ◽  
Anthony Paparo ◽  
Richard Sparks
Keyword(s):  
Carbonic Anhydrase ◽  
River Water ◽  
Food Chains ◽  
Well Water ◽  
Shell Formation ◽  
X Ray ◽  
Molluscan Shell ◽  
Fingernail Clams

Fingernail clams (Muscu1ium transversum) are dominant bottom-dwelling animals in some waters of the midwest U.S. These organisms are key links in food chains leading from nutrients in water and mud to fish and ducks which are utilized by man. In the mid-1950’s, fingernail clams disappeared from a 100-mile section of the Illinois R., a tributary of the Mississippi R. Some factor(s) in the river and/or sediment currently prevent clams from recolonizing areas where they were formerly abundant. Recently, clams developed shell deformities and died without reproducing. The greatest mortality and highest incidence of shell deformities appeared in test chambers containing the highest proportion of river water to well water. The molluscan shell consists of CaCO3, and the tissue concerned in its secretion is the mantle. The source of the carbonate is probably from metabolic CO2 and the maintenance of ionized Ca concentration in the mantle is controlled by carbonic anhydrase. The Ca is stored in extracellular concentric spherical granules(0.6-5.5μm) which represent a large amount of inertCa in the mantle. The purpose of this investigation was to examine the role of raw river water and well water on shell formation in the fingernail clam.

Does a Ribosome Really Read? On the Cognitive Roots and Heuristic Value of Linguistic Metaphors in Molecular Genetics. Part 2

2020 ◽  
Vol 63 (2) ◽  
pp. 46-62
Author(s):  
Suren T. Zolyan
Keyword(s):  
Information Processing ◽  
Genetic Information ◽  
Formal Organization ◽  
Dual Nature ◽  
Reading Frame ◽  
The Core ◽  
Genetic Information Processing ◽  
Cognitive Frame ◽  
Effective Instrument

We discuss the role of linguistic metaphors as a cognitive frame for the understanding of genetic information processing. The essential similarity between language and genetic information processing has been recognized since the very beginning, and many prominent scholars have noted the possibility of considering genes and genomes as texts or languages. Most of the core terms in molecular biology are based on linguistic metaphors. The processing of genetic information is understood as some operations on text – writing, reading and editing and their specification (encoding/decoding, proofreading, transcription, translation, reading frame). The concept of gene reading can be traced from the archaic idea of the equation of Life and Nature with the Book. Thus, the genetics itself can be metaphorically represented as some operations on text (deciphering, understanding, code-breaking, transcribing, editing, etc.), which are performed by scientists. At the same time linguistic metaphors portrayed gene entities also as having the ability of reading. In the case of such “bio-reading” some essential features similar to the processes of human reading can be revealed: this is an ability to identify the biochemical sequences based on their function in an abstract system and distinguish between type and its contextual tokens of the same type. Metaphors seem to be an effective instrument for representation, as they make possible a two-dimensional description: biochemical by its experimental empirical results and textual based on the cognitive models of comprehension. In addition to their heuristic value, linguistic metaphors are based on the essential characteristics of genetic information derived from its dual nature: biochemical by its substance, textual (or quasi-textual) by its formal organization. It can be concluded that linguistic metaphors denoting biochemical objects and processes seem to be a method of description and explanation of these heterogeneous properties.

Exploring the Mechanism of Lingzhu San in Treating Febrile Seizures by Using Network Pharmacology

2020 ◽  
Vol 23 ◽  
Author(s):  
Xiao Zhou ◽  
Xiao-Fei Zhang ◽  
Dong-Yan Guo ◽  
Yan-Jun Yang ◽  
Lin Liu ◽  
...  
Keyword(s):  
Febrile Seizures ◽  
Network Pharmacology ◽  
Biological Processes ◽  
Active Compounds ◽  
Potential Core ◽  
R Language ◽  
The Core ◽  
Multiple Factors ◽  
Therapeutic Mechanism

Objective: Lingzhu San (LZS) is a traditional Chinese medicine (TCM) prescription which can be effective in treating febrile seizures (FS) and has few researches on the mechanisms. In order to better guide the clinical use of LZS, we used the research ideas and methods of network pharmacology to find the potential core compounds, targets and pathways of LZS in the complex TCM system for the treatment of FS, and predict the mechanism. Materials and Methods: Databases such as BATMAN, TCMSP, TCMID, and SWISS TARGET are used to mine the active compounds and targets of LZS, and the target information of FS was obtained through GENECARDS and OMIM. Using Venny2.1.0 and Cytoscape software to locked the potential core compounds and targets of FS. The R language and ClusterProfiler software package were adopt to enrich and analyze the KEGG and GO pathways of the core targets and the biological processes and potential mechanisms of the core targets were revealed. Results: 187 active compounds and 2113 target proteins of LZS were collected. And 38 potential core compounds, 35 core targets and 775 metabolic and functional pathways were screened which involved in mediating FS. Finally, the role of the core compounds, targets and pivotal pathways of LZS regulated FS in the pathogenesis and therapeutic mechanism of FS was discussed and clarified. Conclusions: In this paper, the multi-compounds, multi-targets and multi-pathways mechanism of LZS in the treatment of FS was preliminarily revealed through the analysis of network pharmacology data, which is consistent with the principle of multi-compounds compatibility of TCM prescriptions and unified treatment of diseases from multiple angles, and it provides a new way for TCM to treat complex diseases caused by multiple factors.

Acid ceramidase, a double-edged sword in cancer aggression: A minireview

2020 ◽  
Vol 20 ◽  
Author(s):  
Helen Shiphrah Vethakanraj ◽  
Niveditha Chandrasekaran ◽  
Ashok Kumar Sekar
Keyword(s):  
Cell Fate ◽  
Cancer Progression ◽  
Potential Role ◽  
Tumour Progression ◽  
Acid Ceramidase ◽  
The Core ◽  
The Past ◽  
Sphingosine 1 Phosphate ◽  
Key Enzyme

: Acid ceramidase (AC), the key enzyme of the ceramide metabolic pathway hydrolyzes pro-apoptotic ceramide to sphingosine, which by the action of sphingosine-1-kinase is metabolized to mitogenic sphingosine-1-phosphate. The intracellular level of AC determines ceramide/sphingosine-1-phosphate rheostat which in turn decides the cell fate. The upregulated AC expression during cancerous condition acts as a “double-edged sword” by converting pro-apoptotic ceramide to anti-apoptotic sphingosine-1-phosphate, wherein on one end, the level of ceramide is decreased and on the other end, the level of sphingosine-1-phosphate is increased, thus altogether aggravating the cancer progression. In addition, cancer cells with upregulated AC expression exhibited increased cell proliferation, metastasis, chemoresistance, radioresistance and numerous strategies were developed in the past to effectively target the enzyme. Gene silencing and pharmacological inhibition of AC sensitized the resistant cells to chemo/radiotherapy thereby promoting cell death. The core objective of this review is to explore AC mediated tumour progression and the potential role of AC inhibitors in various cancer cell lines/models.

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