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Introduction to Cells, DNA, and Viruses
Published in Patricia G. Melloy, Viruses and Society, 2023
If we return to the central dogma for a moment, it is important to note that all cells obey the central dogma, but viruses do not. This became completely clear when the first viruses were discovered that did not have a DNA-based genome, and the central dogma had to be revisited because of these discoveries (Baltimore 1970; Temin and Mizutami 1970). Viruses can house their genetic material in the form of either DNA or RNA, single-stranded or double-stranded. There are actually many RNA viruses. A eukaryotic cell will carry its genetic material in the form of double-stranded DNA in the nucleus and make a single-stranded messenger RNA copy of any genes that are expressed. Viruses evolved to consist of all different kinds of genomes, but in the end, each template is adapted or converted in some way to fit in almost seamlessly to use the eukaryotic host cell’s transcriptional and translational mechanisms to make its necessary viral proteins and copy its genome. If the viral genome can somehow be converted to an mRNA transcript to be read by the host cell’s ribosomes, the virus can reproduce in that cell. In addition, because viruses are using the cell’s machinery, even though a virus may start out with different genetic material, viruses still follow the genetic code language of cells where mRNA is translated into certain amino acids that make up proteins (Lostroh 2019).
The Role of Natural Products in COVID-19
Published in Hanadi Talal Ahmedah, Muhammad Riaz, Sagheer Ahmed, Marius Alexandru Moga, The Covid-19 Pandemic, 2023
Iqra Akhtar, Sumera Javad, Tehreema Iftikhar, Amina Tariq, Hammad Majeed, Asma Ahmad, Muhammad Arfan, M. Zia-Ul-Haq
Viruses of zoonotic origin (viruses which can mutate themselves to change their host from some animal to another like human) like CoVs are not easy to study, and extensive research budgets are being deployed to find an effective treatment for patients affected by coronavirus. For this purpose, at first structure elucidation of virus, its source, genome, and infection mechanism are necessary to be known. Another difficulty, while treating viruses, particularly, RNA viruses is their ability to mutate, which make it difficult to prepare any broad-spectrum antiviral agent. This mutating ability of viruses also make them resistant to antiviral drugs as well. If synthetically developed medications for viruses are discussed, there are also related a number of unwanted side effects causing a lot of health problems other than viral sickness. Therefore, a natural drug, particularly a plant-based drug can open new horizons to face the complexities, sickness, and side effects produced by coronavirus and synthetic antiviral agents [6, 21–23].
Infectious disease
Published in Kaji Sritharan, Jonathan Rohrer, Alexandra C Rankin, Sachi Sivananthan, Essential Notes for Medical and Surgical Finals, 2021
Kaji Sritharan, Jonathan Rohrer, Alexandra C Rankin, Sachi Sivananthan
RNA virus (flavivirus) with blood-borne or sexual transmission (former more common). Acute infection is generally mild but leads to chronic carriage in 60–80% of patients. Complications: cryoglobulinaemia. Treatment of chronic hepatitis C infection includes alpha interferon and ribavirin. There is currently no vaccine.
Post COVID-19 Retinal Evaluation Using Optical Coherence Tomography Angiography: A Case Control Study
Published in Ocular Immunology and Inflammation, 2023
Ramy Emad Nageeb Louz, Mohamad Amr Salah Eddin, Tamer A. Macky, Doaa Ahmed Abdelrahman Tolba
The severe acute respiratory syndrome coronavirus 2 (SARS-cov-2) has rapidly spread from its origin in Wuhan, China, to the rest of the world.1 By the end of April 2022, more than 500 million cases had been documented, with more than 6 million deaths.2 Coronaviruses are enveloped positive sense single-stranded RNA viruses,3 transmitted through large droplets but maybe airborne from symptomatic or asymptomatic people.4 The clinical features are variable, from asymptomatic state to acute respiratory distress syndrome and multi organ dysfunction.5 However, the disease spectrum is still evolving, and many features are still to be learnt.6 COVID-19 infections lead to cardiac complications7–9 gastrointestinal,10 hepatic,10 renal,11 neurological12,13 and cutaneous manifestations.14 Blood picture usually shows lymphopenia (56,5%), thrombocytopenia, coagulation disorders, thrombotic events, antiphospholipid antibody.15
COVID-19 and vaccination: myths vs science
Published in Expert Review of Vaccines, 2022
Vivek P. Chavda, Yangmin Chen, Jayant Dave, Zhe-Sheng Chen, Subhash C. Chauhan, Murali M. Yallapu, Vladimir N. Uversky, Rajashri Bezbaruah, Sandip Patel, Vasso Apostolopoulos
In addition to the deaths directly related to COVID-19, there might be many deaths that are associated with COVID-19 that are still unnoticed. Furthermore, the current pandemic posed several questions concerning the efficiency of the health care infrastructure in various developing and undeveloped nations. SARS-CoV-2 infection is also linked to worsened mental health, many who survived COVID-19 have developed long-COVID issues with chronic illnesses, debilitating conditions, and other conditions, which represent a wide assortment of new, returning, or ongoing health problems that are experienced for >4 weeks after first being infected with SARS-CoV-2. Most countries adopt restrictive strategies to reduce the transmission rate and reduce the burden of COVID-19 infection, which has significantly impacted the global economy [28]. At present, vaccines are considered to be the most powerful tool to return normalcy to the world. However, the media and the public concerning the use of vaccines across the world poise several hopes and hypes. Previously, the high mutation rate and the genetic instability also represented a major challenge to developing safe and effective vaccines against RNA viruses. Despite the publication of various reports after the characterization of the virus, there are still many questions that remain unanswered. The immune responses generated by the authorized vaccines are difficult to predict for the different variants of the SARS-CoV-2 virus. There are also certain speculations about the safety and efficacy of vaccine technology behind COVID-19 vaccines and traditional vaccine development.
Tapping the immunological imprints to design chimeric SARS-CoV-2 vaccine for elderly population
Published in International Reviews of Immunology, 2022
Asim Biswas, Rahul Shubhra Mandal, Suparna Chakraborty, George Maiti
Development of vaccine is time consuming and challenging especially for the mutating RNA viruses. However, the mutation rate of SARS-CoV-2 is lower than other single stranded RNA viruses like influenza or HIV [8]. RNA viruses have the tendency to lose infectivity after acquiring mutation but few quasi-species retain infectivity and others become highly infective. These highly infective species bypass the existing immunity to establish themselves in the circulation as a new variant. The repeated viral mutation is well observed during flu season caused by influenza viruses. Every year new flu vaccine is developed based on the previous year’s epidemiological data. SARS-CoV-2 rapid multiplication and infectivity allows the virus to acquire mutations such as D164G, A222V, L18F, P681H and N501Y mutations in the Spike (S) proteins, P323L in the NSP12 protein and R203K, G204R and A220V in the nucleocapsid proteins [9]. Current epidemiological studies have identified new variants in UK (B.1.1.7), South Africa (B.1.351) and Brazil (P.1) and all three have now been detected in the USA [10]. Current vaccines under use can neutralize emerging strains but to what extent they can protect elderly population remains a major concern.