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Introduction to Cells, DNA, and Viruses
Published in Patricia G. Melloy, Viruses and Society, 2023
Viruses can be classified in many ways. Viruses come in a variety of shapes and sizes (Figure 1.3). One initial way to classify a virus is just by type of genome: whether the genome is DNA or RNA. You can also classify viruses based on the hosts that they infect. The International Committee on the Taxonomy of Viruses (ICTV) has subcommittees formed based on viral host as well as genome type. As of 2021, there are three committees devoted to animal viruses of different genome types, one committee for archaeal viruses, one for bacterial viruses, and one for fungal and protist viruses. There is also a committee for plant viruses. ICTV has an online database available to the public (Lefkowitz et al. 2018). David Baltimore, a scientist who has worked on viruses for over 50 years, came up with an initial classification system designating categories of animal viruses based on the type of viral genome that is still used to this day (Baltimore 1971). This classification will be described in more detail later. Dr. Baltimore also has articulated another way to classify viruses, calling them either “equilibrium” or “non-equilibrium” viruses (Baltimore 2017). An equilibrium virus has most likely been infecting the host for a long time and does not cause severe disease in the host. One example would be a rhinovirus causing the common cold in humans. However, a non-equilibrium virus has recently jumped or spilled over from one species to another and tends to be more lethal. An example of a non-equilibrium virus would be HIV causing AIDS in humans (Baltimore 2017).
Virus-Based Nanocarriers for Targeted Drug Delivery
Published in Devarajan Thangadurai, Saher Islam, Charles Oluwaseun Adetunji, Viral and Antiviral Nanomaterials, 2022
Semra Akgönüllü, Monireh Bakhshpour, Yeşeren Saylan, Adil Denizli
Viruses are tiny particles composed of nucleic acid (DNA, RNA). They are self-assembling to prepare a hollow scaffold-depended packing of the viral nucleic acid. The viral protein outer shell (i.e. the so-called capsid) is considered a nano-template because of its dimensions. Most viruses are limited to a special kind of host. Plant viruses infect some plants. Plant viruses have not caused any side effects for humans. They do not offer a biological hazard (Wellink 1998). Viral capsids are highly robust and stable. The genomic materials are encapsulated in the capsid to replicate within a host. Protecting genetic material is the primary task of the capsid, and it does keep viruses stable under situations such as harsh pH and temperature (Pokorski and Steinmetz 2011; Liu et al. 2012). Recently, viruses have been displayed to be genetically adaptable for chemical reactions as reagents, catalysts, and scaffolds applications (Strable and Finn 2009). Virus-based nanocarriers present the important properties of biocompatibility, uniformity, morphological, and simple functionalization. Additionally, virus-based nanoparticles are found in a diversity of characteristic shapes and sizes (Ma et al. 2012). Viral particles are stable in harsh conditions, such as high temperatures, a broad range of pH, and organic solvent water mixtures. These particles are natural structures, symmetrical, and attractive (Steinmetz and Evans 2007; Ma et al. 2012; Alemzadeh et al. 2018).
AI in Fighting against COVID-19
Published in Fadi Al-Turjman, AI-Powered IoT for COVID-19, 2020
Deepanshu Srivastava, S. Rakeshkumar, N. Gayathri, Fadi Al-Turjman
The cell walls of plants are tough, and plant viruses have no specific mechanism for entering the host cell. Person-to-person transmission is the way it is spreading, as shown by significant growth in the various or mostly all countries.
Merits of the ‘good’ viruses: the potential of virus-based therapeutics
Published in Expert Opinion on Biological Therapy, 2021
Qianyu Zhang, Wen Wu, Jinqiang Zhang, Xuefeng Xia
Viruses are known to be able to evolve, infect, and replicate in their respective hosts along their revolutionary paths. Viruses border on the fine line between living organisms and merely chemistry sets, which completely rely on host cells’ machinery to replicate and produce more copies of themselves. Although long have been overshadowed by their pathogenicity, they can be also viewed as a reservoir of biological therapeutics due to their diversity and functions. In fact, viruses have been applied as useful tools in many occasions such as molecular mechanism studies. For example, ever since its discovery in 1898, Tobacco Mosaic Virus (TMV) has been used as a teaching tool in biology classes with its structure extensively studied and understood. Recently, there have been researches using it as a drug delivery platform as plant viruses are unable to infect the mammalian host and show considerable compatibility in mammals [95–97]. Besides that, adenoviral, lentiviral, and retroviral vectors have been used widely for transduction both in cell culture and in vivo to study gene and protein function. Of course, most of these studies were completed in laboratory; therefore, the real challenge in transforming these biological tools into safe and efficacious drugs still remains.
Challenges in the development of egg-independent vaccines for influenza
Published in Expert Review of Vaccines, 2019
Claudia Maria Trombetta, Serena Marchi, Ilaria Manini, Giacomo Lazzeri, Emanuele Montomoli
Plant-based expression systems can be classified as either stable or transient. The former one includes two approaches: the production of recombinant proteins in plants through nuclear genomic integration, and ‘chloroplast transformation’, which is the integration of target genes into the plastid genome. Both have some drawbacks, such as the long time needed to generate stable transformed plants and, often, the low yield of recombinant proteins. Transient systems involve the development of plant virus expression vectors. However, the potential genetic instability of the viral vectors is one of the limitations of the system (Table 1). In order to overcome these limitations, a novel expression system based on a ‘launch vector’ has been developed in which the viral vector is inserted into plants (usually Nicotiana benthamiana) through an Agrobacterium binary plasmid [94,167–171].
Metagenomic analysis of intestinal mucosa revealed a specific eukaryotic gut virome signature in early-diagnosed inflammatory bowel disease
Published in Gut Microbes, 2019
Federica Ungaro, Luca Massimino, Federica Furfaro, Valeria Rimoldi, Laurent Peyrin-Biroulet, Silvia D’Alessio, Silvio Danese
Conversely, other viral families, such as Polydnaviridae and Tymoviridae in UC, and Virgaviridae in CD, that we observed to be less enriched in IBD patients and to negatively correlate with the presence of other viruses, might be somehow considered protective in the human host.15 This is interesting, because Polydnaviridae, Tymoviridae, and Virgaviridae are viruses that typically infects plants and insects and may have reached the gut through the diet.3 The trans-kingdom interaction15 between viruses and hosts, such as plant and insect viruses that colonize human tissues, has already been reported in the past for Tobacco Mosaic Virus (TMV), against which antibodies were found in human sera.42 Unlike animal viruses, plant viruses cannot replicate in humans or other animals because of the lack of specific receptors. Nevertheless, they still can induce the host immune response, as shown for the cowpea mosaic virus in mice.43,44