scholarly journals A Comparative Review of Natural and Synthetic Biopolymer Composite Scaffolds

Polymers ◽  
2021 ◽  
Vol 13 (7) ◽  
pp. 1105
Author(s):  
M. Sai Bhargava Reddy ◽  
Deepalekshmi Ponnamma ◽  
Rajan Choudhary ◽  
Kishor Kumar Sadasivuni
Keyword(s):  
Careful Consideration ◽  
Cellular Systems ◽  
Host Cells ◽  
Composite Scaffolds ◽  
Cellular Environment ◽  
Multi Stage ◽  
Essential Components ◽  
Comparative Review ◽  
Scaffold Materials ◽  
Natural And Synthetic

Tissue engineering (TE) and regenerative medicine integrate information and technology from various fields to restore/replace tissues and damaged organs for medical treatments. To achieve this, scaffolds act as delivery vectors or as cellular systems for drugs and cells; thereby, cellular material is able to colonize host cells sufficiently to meet up the requirements of regeneration and repair. This process is multi-stage and requires the development of various components to create the desired neo-tissue or organ. In several current TE strategies, biomaterials are essential components. While several polymers are established for their use as biomaterials, careful consideration of the cellular environment and interactions needed is required in selecting a polymer for a given application. Depending on this, scaffold materials can be of natural or synthetic origin, degradable or nondegradable. In this review, an overview of various natural and synthetic polymers and their possible composite scaffolds with their physicochemical properties including biocompatibility, biodegradability, morphology, mechanical strength, pore size, and porosity are discussed. The scaffolds fabrication techniques and a few commercially available biopolymers are also tabulated.

scholarly journals Milling technological experiments to reduce Fusarium toxin contamination in wheat

2015 ◽  
Vol 8 (1) ◽  
pp. 55-62
Author(s):  
A. Véha ◽  
P. Szabó ◽  
T. Bartók ◽  
E. Gyimes
Keyword(s):  
Winter Wheat ◽  
Mass Loss ◽  
Milling Process ◽  
Careful Consideration ◽  
Fusarium Toxin ◽  
Toxin Content ◽  
Multi Stage ◽  
Public Consumption ◽  
By Products

Abstract We examine 4 different DON-toxin-containing (0.74 - 1.15 - 1.19 - 2.14 mg/kg) winter wheat samples: they were debranned and undebranned, and we investigated the flour’s and the by-products’ (coarse, fine bran) toxin content changes. SATAKE lab-debranner was used for debranning and BRABENDER lab-mill for the milling process. Without debranning, two sample flours were above the DON toxin limit (0.75 mg/kg), which are waste. By minimum debranning (and minimum debranning mass loss; 6-8%), our experience with whole flour is that the multi-stage debranning measurement significantly reduces the content of the flour’s DON toxin, while the milling by-products, only after careful consideration and DON toxin measurements, may be produced for public consumption and for feeding.

3D Composites Based on Hydroxyapatite-Chitosan-Polysiloxane as a Biomimetic Scaffold Materials

2007 ◽  
Vol 1007 ◽  
Author(s):  
Andrónico Neira-Carrillo ◽  
José Ignacio Arias ◽  
M. Soledad Fernández ◽  
Ranjith Krishna Pai ◽  
C Claudia Quilodrán ◽  
...  
Keyword(s):  
Body Fluid ◽  
Three Dimensional ◽  
Subcutaneous Implantation ◽  
Composite Scaffolds ◽  
High Viability ◽  
Phosphorylation Reaction ◽  
Biomimetic Scaffold ◽  
Sublimation Method ◽  
Scaffold Materials ◽  
Solid Liquid

ABSTRACTThree-dimensional (3D) composites of hydroxyapatite, phosphorylated and/or nonphosphorylated chitosan and sulphonated methylsiloxane polymer (HA/P-CHI: CHI/ S-MSP) were prepared by solid-liquid phase separation and solvent sublimation method. The HA, P-CHI and S-MSP were synthesized by chemical continuous wet-calcination, phosphorylation reaction and hydrosilylation-sulphonation reactions, respectively. 3D composites were analyzed by scanning electron microscopy (SEM). Swelling ability, stability and formation of HA particles on the composites immersed in simulated body fluid (SBF) were analyzed. Osteoblasts showed high viability when cultured on composite scaffolds. 3D composites were not degraded after 8 weeks of subcutaneous implantation in rats.

scholarly journals The organization of engaged and quiescent translocons in the endoplasmic reticulum of mammalian cells

2004 ◽  
Vol 164 (7) ◽  
pp. 997-1007 ◽  
Author(s):  
Erik L. Snapp ◽  
Gretchen A. Reinhart ◽  
Brigitte A. Bogert ◽  
Jennifer Lippincott-Schwartz ◽  
Ramanujan S. Hegde
Keyword(s):  
Endoplasmic Reticulum ◽  
Mammalian Cells ◽  
Signal Recognition Particle ◽  
Resonance Energy Transfer ◽  
Resonance Energy ◽  
Cellular Environment ◽  
Essential Components ◽  
Nascent Chain ◽  
Functional Components

Protein translocons of the mammalian endoplasmic reticulum are composed of numerous functional components whose organization during different stages of the transport cycle in vivo remains poorly understood. We have developed generally applicable methods based on fluorescence resonance energy transfer (FRET) to probe the relative proximities of endogenously expressed translocon components in cells. Examination of substrate-engaged translocons revealed oligomeric assemblies of the Sec61 complex that were associated to varying degrees with other essential components including the signal recognition particle receptor TRAM and the TRAP complex. Remarkably, these components not only remained assembled but also had a similar, yet distinguishable, organization both during and after nascent chain translocation. The persistence of preassembled and complete translocons between successive rounds of transport may facilitate highly efficient translocation in vivo despite temporal constraints imposed by ongoing translation and a crowded cellular environment.

scholarly journals Analysis of P granules in vivo and ex vivo

2018 ◽  
Author(s):  
Andrea Putnam ◽  
Madeline Cassani ◽  
Jarrett Smith ◽  
Geraldine Seydoux
Keyword(s):  
Liquid Phase ◽  
Neuronal Degeneration ◽  
Ex Vivo ◽  
P Granules ◽  
C Elegans ◽  
Rna Granules ◽  
Liquid Phases ◽  
Cellular Environment ◽  
Essential Components

Corrected version -This version can be cited. RNA granules are dynamic sub-cellular compartments that lack enveloping membranes. RNA granules have been proposed to form by liquid-liquid phase separation, a thermodynamic process that partitions molecules between dilute and condensed liquid phases 1. P granules are archetypal RNA granules in C. elegans that display liquid-like behaviors 2. Here we describe in vivo and ex vivo approaches to analyze the material properties of P granules. We find that the liquid phase of P granules is stabilized by a molecularly-distinct, enveloping shell that is intrinsically non-dynamic. Consistent with a gel phase, the shell is resistant to dilution, high salt, and aliphatic alcohols, and dissolves in SDS. Solidification of RNA granules has been linked to neuronal degeneration 3. Our findings suggest that gel-like polymers are essential components of RNA granules that help stabilize liquid phases in the cellular environment.

scholarly journals Adaptation to host cell environment during experimental evolution of Zika virus

2021 ◽  
Author(s):  
Vincent Grass ◽  
Emilie Hardy ◽  
Kassian Kobert ◽  
Soheil Rastgou Talemi ◽  
Elodie Décembre ◽  
...  
Keyword(s):  
Host Cell ◽  
Zika Virus ◽  
Immune Escape ◽  
Viral Evolution ◽  
Time Lag ◽  
Host Cells ◽  
Host Responses ◽  
Type I ◽  
Zikv Infection ◽  
Cellular Environment

Abstract Zika virus (ZIKV) infection can cause important developmental and neurological defects in Humans. Type I/III interferon responses control ZIKV infection and pathological processes, yet the virus has evolved various mechanisms to defeat these host responses. Here, we established a pipeline to delineate at high-resolution the genetic evolution of ZIKV in a controlled host cell environment. We uncovered that serially passaged ZIKV acquired increased infectivity and simultaneously developed a resistance to TLR3-induced restriction. We built a mathematical model that suggests that the increased infectivity is due to a reduced time-lag between infection and viral replication. We found that this adaptation is cell-type specific, suggesting that different cell environments may drive viral evolution along different routes. Deep-sequencing of ZIKV populations pinpointed mutations whose increased frequencies temporally coincide with the acquisition of the adapted phenotype. We functionally validated S455L, a substitution in ZIKV envelope (E) protein, recapitulating the adapted phenotype. Its positioning on the E structure suggests a putative function in protein refolding/stability. Taken together, our results uncovered ZIKV adaptations to the cellular environment leading to accelerated replication onset coupled with resistance to TLR3-induced antiviral response. Our work provides insights into Zika virus adaptation to host cells and immune escape mechanisms.

scholarly journals Bioluminescent:fluorescent Trypanosoma cruzi Reporter Strains as Tools for Exploring Chagas Disease Pathogenesis and Drug Activity

2020 ◽  
Vol 26 ◽  
Author(s):  
Martin C. Taylor ◽  
Alexander I. Ward ◽  
Francisco Olmo ◽  
Amanda F. Francisco ◽  
Shiromani Jayawardhana ◽  
...  
Keyword(s):  
Trypanosoma Cruzi ◽  
Chagas Disease ◽  
Parasite Burden ◽  
New Drugs ◽  
Host Cells ◽  
Complex Nature ◽  
Disease Pathogenesis ◽  
Drug Activity ◽  
Cellular Environment

: Chagas disease results from infection with the trypanosomatid parasite Trypanosoma cruzi. Progress in developing new drugs has been hampered by the long term and complex nature of the condition and by our limited understanding of parasite biology. Technical difficulties in assessing the parasite burden during the chronic stage of infection have also proved to be a particular challenge. In this context, the development of non-invasive, highly sensitive bioluminescence imaging procedures, based on parasites that express a red-shifted luciferase, has greatly enhanced our ability to monitor infections in experimental models. Applications of this methodology have led to new insights into tissue tropism and infection dynamics, and have been a major driver in drug development. The system has been further modified by the generation of parasite reporter lines that express bioluminescent:fluorescent fusion proteins, an advance that has allowed chronic infections in mice to be examined at a cellular level. By exploiting bioluminescence to identify the rare sites of tissue infection, and fluorescence to detect T. cruzi at the level of individual host cells in histological sections, it has been possible to investigate the replication and differentiation status of parasites in vivo and to examine the cellular environment of infection foci. In combination, these data are providing a framework for the detailed dissection of disease pathogenesis and drug activity.

Loss of IKK subunits limits NF-κB signaling in reovirus infected cells

2019 ◽  
Author(s):  
Andrew J. McNamara ◽  
Pranav Danthi
Keyword(s):  
Gene Expression ◽  
Transcription Factors ◽  
Virus Replication ◽  
Nuclear Translocation ◽  
Innate Immune ◽  
Host Cells ◽  
Reovirus Infection ◽  
Cellular Environment ◽  
Ikk Complex ◽  
Infected Cells

ABSTRACTViruses commonly antagonize innate immune pathways that are primarily driven by Nuclear Factor-κB (NF-κB), Interferon Regulatory Factor (IRF) and Signal Transducer and Activator of Transcription (STAT) family of transcription factors. Such a strategy allows viruses to evade immune surveillance and maximize their replication. Using an unbiased RNA-seq based approach to measure gene expression induced by transfected viral genomic RNA (vgRNA) and reovirus infection, we discovered that mammalian reovirus inhibits host cell innate immune signaling. We found that while vgRNA and reovirus infection both induce a similar IRF dependent gene expression program, gene expression driven by the NF-κB family of transcription factors is lower in infected cells. Potent agonists of NF-κB, such as Tumor Necrosis Factor alpha (TNFα) and vgRNA, failed to induce NF-κB dependent gene expression in infected cells. We demonstrate that NF-κB signaling is blocked due to loss of critical members of the Inhibitor of KappaB Kinase (IKK) complex, NF-κB Essential MOdifier (NEMO) and IKKβ. The loss of the IKK complex components prevents nuclear translocation and phosphorylation of NF-κB, thereby preventing gene expression. Our studies demonstrate that reovirus infection selectively blocks NF-κB, likely to counteract its antiviral effects and promote efficient viral replication.IMPORTANCEHost cells mount a response to curb virus replication in infected cells and prevent infection of neighboring, as yet uninfected cells. The NF-κB family of proteins is important for the cell to mediate this response. In this study, we show that in cells infected with mammalian reovirus, NF-κB is inactive. Further, we demonstrate that NF-κB is rendered inactive because virus infection results in reduced levels of upstream intermediaries (called IKKs) that are needed for NF-κB function. Based on previous evidence that active NF-κB limits reovirus infection, we conclude that inactivating NF-κB is a viral strategy to produce a cellular environment that is favorable for virus replication.

scholarly journals The Influenza A Virus Genotype Determines the Antiviral Function of NF-κB

2016 ◽  
Vol 90 (17) ◽  
pp. 7980-7990 ◽  
Author(s):  
Sharmistha Dam ◽  
Michael Kracht ◽  
Stephan Pleschka ◽  
M. Lienhard Schmitz
Keyword(s):  
Transcription Factor ◽  
Influenza A Virus ◽  
Influenza A ◽  
Genome Engineering ◽  
Reverse Genetics ◽  
Host Cells ◽  
Avian Host ◽  
Essential Components ◽  
Antiviral Function

ABSTRACTThe role of NF-κB in influenza A virus (IAV) infection does not reveal a coherent picture, as pro- and also antiviral functions of this transcription factor have been described. To address this issue, we used clustered regularly interspaced short palindromic repeat with Cas9 (CRISPR-Cas9)-mediated genome engineering to generate murine MLE-15 cells lacking two essential components of the NF-κB pathway. Cells devoid of either the central NF-κB essential modulator (NEMO) scaffold protein and thus defective in IκB kinase (IKK) activation or cells not expressing the NF-κB DNA-binding and transactivation subunit p65 were tested for propagation of the SC35 virus, which has an avian host range, and its mouse-adapted variant, SC35M. While NF-κB was not relevant for replication of SC35M, the absence of NF-κB activity increased replication of the nonadapted SC35 virus. This antiviral effect of NF-κB was most prominent upon infection of cells with low virus titers as they usually occur during the initiation phase of IAV infection. The defect in NF-κB signaling resulted in diminished IAV-triggered phosphorylation of interferon regulatory factor 3 (IRF3) and expression of the antiviral beta interferon (IFN-β) gene. To identify the viral proteins responsible for NF-κB dependency, reassortant viruses were generated by reverse genetics. SC35 viruses containing the SC35M segment encoding neuraminidase (NA) were completely inert to the inhibitory effect of NF-κB, emphasizing the importance of the viral genotype for susceptibility to the antiviral functions of NF-κB.IMPORTANCEThis study addresses two different issues. First, we investigated the role of the host cell transcription factor NF-κB in IAV replication by genetic manipulation of IAVs by reverse genetics combined with targeted genome engineering of host cells using CRISPR-Cas9. The analysis of these two highly defined genetic systems indicated that the IAV genotype can influence whether NF-κB displays an antiviral function and thus might in part explain incoherent results from the literature. Second, we found that perturbation of NF-κB function greatly improved the growth of a nonadapted IAV, suggesting that NF-κB may contribute to the maintenance of the host species barrier.

scholarly journals Broad-spectrum antivirals of protoporphyrins inhibit the entry of highly pathogenic emerging viruses

2020 ◽  
Author(s):  
Shengsheng Lu ◽  
Xiaoyan Pan ◽  
Daiwei Chen ◽  
Xi Xie ◽  
Yan Wu ◽  
...  
Keyword(s):  
Puerto Rico ◽  
Broad Spectrum ◽  
Influenza A ◽  
Rational Design ◽  
Host Cells ◽  
Mechanistic Study ◽  
Control Group ◽  
Enveloped Viruses ◽  
Essential Components ◽  
Antiviral Activities

AbstractSevere emerging and re-emerging viral infections such as Lassa fever, Avian influenza (AI), and COVID-19 caused by SARS-CoV-2 urgently call for new strategies for the development of broad-spectrum antivirals targeting conserved components in the virus life cycle. Viral lipids are essential components, and viral-cell membrane fusion is the required entry step for most unrelated enveloped viruses. In this paper, we identified a porphyrin derivative of protoporphyrin IX (PPIX) that showed broad antiviral activities in vitro against a panel of enveloped pathogenic viruses including Lassa virus (LASV), Machupo virus (MACV), and SARS-CoV-2 as well as various subtypes of influenza A viral strains with IC50 values ranging from 0.91±0.25 μM to 1.88±0.34 μM. A mechanistic study using influenza A/Puerto Rico/8/34 (H1N1) as a testing strain showed that PPIX inhibits the infection in the early stage of virus entry through biophysically interacting with the hydrophobic lipids of enveloped virions, thereby inhibiting the formation of the negative curvature required for fusion and blocking the entry of enveloped viruses into host cells. In addition, the preliminary antiviral activities of PPIX were further assessed by testing mice infected with the influenza A/Puerto Rico/8/34 (H1N1) virus. The results showed that compared with the control group without drug treatment, the survival rate and mean survival time of the mice treated with PPIX were apparently prolonged. These data encourage us to conduct further investigations using PPIX as a lead compound for the rational design of lipid-targeting antivirals for the treatment of infection with enveloped viruses.

scholarly journals SARS-CoV-2 desensitizes host cells to interferon through inhibition of the JAK-STAT pathway

2020 ◽  
Author(s):  
Da-Yuan Chen ◽  
Nazimuddin Khan ◽  
Brianna J. Close ◽  
Raghuveera K. Goel ◽  
Benjamin Blum ◽  
...  
Keyword(s):  
Cell Lines ◽  
Immune Evasion ◽  
Cell Types ◽  
Cellular Systems ◽  
Host Cells ◽  
Interferon Signaling ◽  
Multiple Organs ◽  
Immortalized Cell ◽  
Antiviral Innate Immunity ◽  
Stat Pathway

AbstractSARS-CoV-2 can infect multiple organs, including lung, intestine, kidney, heart, liver, and brain. The molecular details of how the virus navigates through diverse cellular environments and establishes replication are poorly defined. Here, we performed global proteomic analysis of the virus-host interface in a newly established panel of phenotypically diverse, SARS-CoV-2-infectable human cell lines representing different body organs. This revealed universal inhibition of interferon signaling across cell types following SARS-CoV-2 infection. We performed systematic analyses of the JAK-STAT pathway in a broad range of cellular systems, including immortalized cell lines and primary-like cardiomyocytes, and found that several pathway components were targeted by SARS-CoV-2 leading to cellular desensitization to interferon. These findings indicate that the suppression of interferon signaling is a mechanism widely used by SARS-CoV-2 in diverse tissues to evade antiviral innate immunity, and that targeting the viral mediators of immune evasion may help block virus replication in patients with COVID-19.

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