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Vectored vaccines
Published in Amine Kamen, Laura Cervera, Bioprocessing of Viral Vaccines, 2023
Zeyu Yang, Kumar Subramaniam, Amine Kamen
The standard VSV particle is a bullet-shaped, single-strand, negative-sense RNA virus with 65 × 180 nm. The viral genome is about 11 kilobases, which encodes five major viral proteins including nucleoprotein (N), phosphoprotein (P), matrix protein (M), glycoprotein (G), and the viral polymerase (L) [65]. The N protein associates to form viral nucleocapsid for genomic RNA, which serves as functional template for viral replication and transcription. This protein is also the most abundant protein expressed in infected cells. The M protein is the main protein in the VSV particle. The M protein has various functions in infected cells. This protein can regulate the viral transcription, inhibit the gene expression of host cells, and contribute to virus budding. The P and L genomic motifs associate to express the viral RNA polymerase with the functions of transcriptase and replicase. The G protein is a transmembrane glycoprotein on the virus surface with a trimeric spike-like structure. The G protein is responsible for virus attachment to the receptors of host cells.
Biology of Coronaviruses with Special Reference to SARS-CoV-2
Published in Joystu Dutta, Srijan Goswami, Abhijit Mitra, COVID-19 and Emerging Environmental Trends, 2020
Joystu Dutta, Srijan Goswami, Abhijit Mitra
The assembly of newly synthesized viral particles begins with the systematic aggregation of +ve ssRNA and viral structural components (Lim, 2016). The assembly of newly synthesized coronavirus particles is accomplished through the budding of nucleocapsid through membranes early in the secretory pathway from the endoplasmic reticulum to the Golgi intermediate compartment or ERGIC. The contribution of the host cell during this process (in relation to SARS-CoV-2) is still under investigation. The M-protein also interacts with E-protein and S-protein to complete the assembly of the mature virus particles. Studies have shown that M-protein controls and regulates the viral assembly and mediates the budding of newly synthesized virus particles (Neuman et al., 2011). Following the assembly and budding, the newly assembled viral particles are transported in vesicles and eventually released by exocytosis.
Coronavirus
Published in Suman Lata Tripathi, Kanav Dhir, Deepika Ghai, Shashikant Patil, Health Informatics and Technological Solutions for Coronavirus (COVID-19), 2021
Most of the protein-protein interactions required for assembly of coronaviruses are directed by M protein. However, M protein expression alone is not sufficient for virion formation, as M protein expression alone cannot result in the formation of virus-like particles (VLPs). When M protein is expressed along with E protein it results in the formation of VLPs; therefore these two proteins are known to function together to produce coronavirus envelopes [47]. N protein has roles in enhancing the VLP formation, thus the fusion of the encapsidated genomes into the ERGIC enhances the formation of the viral envelope. The S protein is incorporated into virions at this step, but is not required for assembly. The ability of the S protein to interact with the M protein in the ERGIC is critical for its incorporation into virions [48]. M protein interactions are responsible for promoting the envelope maturation. E protein assists M protein in assembly of the virion; E protein is known to induce membrane curvature. Additionally, the E protein is known to play a role in altering the secretory pathway of the host organism and promotes the release of virions [49]. Binding of the M protein to the nucleocapsid plays a role in promoting the completion of virion assembly. The interaction between M protein and nucleocapsid has been mapped to the C-terminus of the endodomain of M with C-terminal domain of the N protein [50]. Among different RNA species produced during infection, the N protein selectively packages only positive-sense full-length genomes. In the coding sequence of nsp15 a packaging signal has been identified for MHV. It was concluded that any mutation in this signal does not really affect the multiplication of the virus. Also, the underlying mechanism as to how this packaging signal works has not been determined [51]. Following assembly of components and budding, virions are transported to the cell surface in vesicles and released by exocytosis. In many coronaviruses, the S protein does not get assembled into virions, it moves to the cell surface where it is known to play a role in mediating cell-cell fusion between infected cells and uninfected cells. This results in the formation of large multinucleated cells, which provides an advantage to the virus and it spreads within the infected organism being undetected or without getting neutralized by the action of virus-specific antibodies. Figure 4.3 summarizes the sequence of events involved from infection to release of virions.
Preparation and characterization of polyamidoamine dendrimers conjugated with cholesteryl-dipeptide as gene carriers in HeLa cells
Published in Journal of Biomaterials Science, Polymer Edition, 2022
Le Thi Thuy, Minyoung Choi, Minhyung Lee, Joon Sig Choi
HeLa cells were seeded at a density of 13 × 103 cells/well in 96-well plates and cultured in 100 µL of medium containing 10% FBS and 1% (w/v) penicillin/streptomycin at 37 °C in a humidified atmosphere of 5% CO2 for 24 h. Polyplexes (10 µL) prepared at various weight ratios were injected into the cells, followed by incubation for 24 h at RT. The medium was then removed, and cells were washed with DPBS and lysed for 30 min at RT in 50 µL Reporter Lysis Buffer (Promega, Madison, WI, USA). Protein content was measured using the Pierce Micro BCATM Protein Assay Kit (Thermo Scientific, Rockford, IL, USA). Absorption was measured at 570 nm using a VersaMax microplate reader (Molecular Devices, Sunnyvale, CA, USA) and compared to a standard curve calibrated with BSA samples of known concentrations. The results were expressed as relative light units (RLU) per mg of cell protein lysate.
Biosurfactants produced from corncob: a bibliometric perspective of a renewable and promising substrate
Published in Preparative Biochemistry & Biotechnology, 2022
Hysla Maria Albuquerque Resende Nunes, Isabela Maria Monteiro Vieira, Brenda Lohanny Passos Santos, Daniel Pereira Silva, Denise Santos Ruzene
However, substances with surfactant properties can also be synthesized by microorganisms that produce so-called biosurfactants (BSs), whose main producers are bacteria, fungi, and yeasts.[3,7] Biosurfactants present a surface-active molecule of amphiphilic nature, with hydrophilic moieties composed by carbohydrates, phosphates, amino acids, proteins, carboxylic acids, or alcohols, and lipophilic moieties constituted by unsaturated or saturated hydrocarbon chains or fatty acids.[8,9] All these molecular components are assembled by biochemical linkages, such as ethers (C–O–C), amides (N–C=O), and esters (O–C=O).[8] This structure allows biosurfactants to accumulate between fluid phases, reducing the surface and interfacial tensions of liquids, making them more biocompatible than those of chemical origin. Based on the chemical structure of their hydrophobic region, BSs can be divided into low-molecular-weight (LMW) and high-molecular-weight (HMW). LMW biosurfactants can be further classified as glycolipids (rhaminolipid, sophorolipid, mannosylerythritol lipid), phospholipids (phosphatidylethanolamine), and lipopeptides (surfactin, viscosin, serrawettin, iturin), whereas HMW comprises polymers (emulsan, liposan, biodispersan) and particulate biosurfactants (lipoteichoic acid, M protein, prodigiosin).[3,10]
Repurposing pharmaceutical excipients as an antiviral agent against SARS-CoV-2
Published in Journal of Biomaterials Science, Polymer Edition, 2022
Manisha Malani, Prerana Salunke, Shraddha Kulkarni, Gaurav K. Jain, Afsana Sheikh, Prashant Kesharwani, Jayabalan Nirmal
SARS-CoV-2 shows a major similarity to SARS-CoV, a virus of the same genera which caused the SARS outbreak during 2002–2004. It belongs to family Coronaviridae and genera beta coronavirus (genera with the largest known RNA viruses) [41]. It is a RNA virus (single-stranded, positive-sense) with a genome of around 30 kb and at least 10 Open Reading Frames (ORF) [42]. Phylogenetically, SARS-CoV-2 is similar to existing family virus (MERS-CoV and SARS-CoV) majorly having four structural proteins (Spike (S), Envelope (E) glycoprotein, Nucleocapsid (N) and Membrane (M) protein) with 5–8 accessory protein and 16 nonstructural protein [43]. The crowns like spike glycoprotein located on the outermost surface of the virion undergoes cleavage into the amino terminal S1 subunit facilitating the incorporation of the virus into the host cell. The virus also cleaves to liberate carboxyl terminal S2 subunit that helps in virus-cell membrane fusion [44]. The amino terminal S1 subunit further divides into N-terminal domain (NTD) and receptor-binding domain (RBD) that also encourages the entry of virus into the host cell. This could also serve as a potential target for vaccine and antisera for neutralization of such pathogenic moieties [45].