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Naturally Occurring Alkaloids with Anti-HIV Activity
Published in Namrita Lall, Medicinal Plants for Cosmetics, Health and Diseases, 2022
HIV spreads through parenteral, vertical or sexual transmission, and can be transmitted via the exchange of a variety of body fluids from infected people, such as blood, breast milk, semen and vaginal secretions. HIV can be transmitted from a mother to her child during pregnancy and delivery. Currently, more than 90% of all adolescent and adult HIV infections are a consequence of heterosexual intercourse. Three mechanisms of viral spread have been described. The first mechanism involves entry in which cell-free virions bind to host cells by receptor interactions. Second, an infected cell can directly infect another cell, without virion release; and third, dendritic cells (DCs) can capture viral particles by binding to C-type lectins, presenting the virus to surrounding lymphocytes in a cell environment known as a viral synapse. This last mechanism increases the efficiency of infection and prevents viral neutralization by antibodies or complements, and should therefore be considered as an important target to virucides (Bedoya et al., 2008, WHO, 2020).
The Viruses
Published in Julius P. Kreier, Infection, Resistance, and Immunity, 2022
Viruses infect and cause disease in both plants and animals. They were initially identified as “filterable agents.” This terminology developed because viral infections could be produced with fluids which were filtered to eliminate bacteria. This separation is possible because viruses are much smaller than bacteria. Viruses are in fact small packets of protein and nucleic acid that only reproduce inside a susceptible host cell. The proteins of viruses have structural, enzymatic, or regulatory properties. The function of the virion or virus particle is to initiate an infection and promote the replication of more virions by exploiting the environment and enzymes of the host cell.
Non-Photocatalytic and Photocatalytic Inactivation of Viruses Using Antiviral Assays and Antiviral Nanomaterials
Published in Devarajan Thangadurai, Saher Islam, Charles Oluwaseun Adetunji, Viral and Antiviral Nanomaterials, 2022
Suman Tahir, Noor Tahir, Tajamal Hussain, Zubera Naseem, Muhammad Zahid, Ghulam Mustafa
For observing the variations in host cells once affected through viruses, virion adsorption assay is used (Alonas et al. 2014). This effective method for demonstrating the process of virus contagion in host cells is broadly employed in the antiviral assessment of NPs. Using confocal microscopy imaging, indirect immunofluorescence analysis can also be operated to exhibit variations in the viral proteins’ structure earlier, and afterward treatment through NPs. The assay is an imagining method to show the antiviral consequences of NPs.
Diagnostic approaches for dengue infection
Published in Expert Review of Molecular Diagnostics, 2023
Gaythri Thergarajan, Shamala Devi Sekaran
DENV is a single-stranded positive-sense RNA virus of approximately 50 nm in length. The 11 kb genome of each virion encodes three structural proteins (capsid, C; precursor membrane, prM; and envelope, E) and seven non-structural (NS) proteins (NS1, NS2A, NS2B, NS3, NS4A, NS4B, and NS5) [60]. These non-structural proteins play roles in viral replication and assembly. Structurally, a virion consists of a nucleocapsid, enveloped by an outer glycoprotein shell and an inner lipid bilayer. Surface projections in the lipid membrane consist of E and membrane (M) glycoproteins [61]. Nucleic acid amplification tests and identification of virus antigen or antibody serve as the predominant means of detection of DENV, based on the molecular or immunological response to specified viral structural components. Commonly used methods are reverse transcription polymerase chain reaction (RT-PCR), nucleic acid sequence-based amplification (NASBA), and transcription-mediated amplification (TMA).
Mpox: epidemiology, clinical manifestations and recent developments in treatment and prevention
Published in Expert Review of Anti-infective Therapy, 2023
Nikil Selvaraj, Shreya Shyam, Puvin Dhurairaj, Kaviarasan Thiruselvan, Akil Thiruselvan, Yochana Kancherla, Pritika Kandamaran
Orthopoxviruses (OPXV) demonstrate immunological cross-reactivity and cross-protection. Orthopoxviruses are large (size range: 140–450 nanometer) viruses with a brick-like shape with genomes containing over 200 genes and ranging in size from 200–500 kbp [5]. Many of the OPXV genes are not required for virus replication in cell culture, but they may be crucial for the host’s antiviral defenses. Complex molecular mechanisms are used by all poxviruses to complete their replication cycle in the cytoplasm of infected cells. The vaccinia virus, which was used to create the vaccine that contributed to the worldwide eradication of smallpox, has an intracellular replication cycle that has been extensively studied; important aspects of this replication cycle are shared by all poxviruses [7]. The internal mature virion and the external wrapped virion, which differ in their production of surface glycoproteins, are two different forms of the virus that might start the infection cycle [7].
Next-generation sequencing for the diagnosis of hepatitis B: current status and future prospects
Published in Expert Review of Molecular Diagnostics, 2021
Selene Garcia-Garcia, Maria Francesca Cortese, Francisco Rodríguez-Algarra, David Tabernero, Ariadna Rando-Segura, Josep Quer, Maria Buti, Francisco Rodríguez-Frías
Recently, Sanger sequencing has been used to identify the different species of HBV RNA produced during infection. Different viral particles are produced during the natural HBV life cycle, including RNA-containing virions. Considering that circulating HBV RNA is a direct product of cccDNA activity [51], the detection and classification of the different RNA species is of great interest in patient follow-up. Stadelmayer et al. carried out a qualitative approach called HBV full-length 5ʹRACE (rapid amplification of cDNA ends), which enabled the measurement and discrimination of the different HBV RNA species in both cultured hepatocytes and plasma from patients with chronic hepatitis B [52]. Through cloning and Sanger sequencing of 5ʹRACE profiles, they observed that the composition of the viral RNA species can vary among patients, identifying different PCR patterns and specific splicing variants. Notably, they detected a variety of transcripts for the X gene (both longer and shorter than the canonical HBx transcript) due to a high heterogeneity in transcriptional start sites (TSSs).