The SARS-CoV-2 Omicron Variant and its Multiple Sub-lineages: Transmissibility, Vaccine Development, Antiviral Drugs, Monoclonal Antibodies, and Strategies for Infection Control – a Review

The Omicron (B.1.1.529), fifth variant of concern (VOC) of SARS-CoV-2, initially identified following a steep increase in COVID-19 cases in Southern Africa in November 2021. It is a highly-mutated variant and is more contagious as compared with the Delta variant, however less deadly. Due to its high transmission rate, it spreads dramatically, and causing huge surges worldwide. It causes "mild infection”, with hospitalisations less likely to occur. However, this variant is known to show resistance to neutralizing antibodies (nAbs) generated through vaccination and/or prior infection as well as to monoclonal antibodies (mAbs) used to treat COVID-19 patients. In many countries, booster doses of vaccines have been recommended to increase the protective levels of antibodies in vaccinated individuals. Along with the implementation of appropriate prevention and control strategy measures, current efforts are also focussed on the development of better vaccines and mAbs to counter this variant. This review highlights the global health concerns and challenges posed by the Omicron variant and present an update on its sub-lineages. © 2023 Wiley-VCH GmbH.

SARS-CoV-2 emerging Omicron subvariants with a special focus on BF.7 and XBB.1.5 recently posing fears of rising cases amid ongoing COVID-19 pandemic

The severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) Omicron versions have been the sole one circulating for quite some time. Subvariants BA.1, BA.2, BA.3, BA.4, and BA.5 of the Omicron emerged over time and through mutation, with BA.1 responsible for the most severe global pandemic between December 2021 and January 2022. Other Omicron subvariants such as BQ.1, BQ.1.1, BA.4.6, BF.7, BA.2.75.2, XBB.1 appeared recently and could cause a new wave of increased cases amid the ongoing COVID-19 pandemic. There is evidence that certain Omicron subvariants have increased transmissibility, extra spike mutations, and ability to overcome protective effects of COVID-19 neutralizing antibodies through immunological evasion. In recent months, the Omicron BF.7 subvariant has been in the news due to its spread in China and a small number of other countries, raising concerns about a possible rebound in COVID-19 cases. More recently, the Omicron XBB.1.5 subvariant has captured international attention due to an increase in cases in the United States. As a highly transmissible sublineage of Omicron BA.5, as well as having a shorter incubation time and the potential to reinfect or infect immune population, BF.7 has stronger infection ability. It appears that the regional immunological landscape is affected by the amount and timing of previous Omicron waves, as well as the COVID-19 vaccination coverage, which in turn determines whether the increased immune escape of BF.7 and XBB.1.5 subvariants is sufficient to drive new infection waves. Expanding our understanding of the transmission and efficacy of vaccines, immunotherapeutics, and antiviral drugs against newly emerging Omicron subvariants and lineages, as well as bolstering genomic facilities for tracking their spread and maintaining a constant vigilance, and shedding more light on their evolution and mutational events, would help in the development of effective mitigation strategies. Importantly, reducing the occurrence of mutations and recombination in the virus can be aided by bolstering One health approach and emphasizing its significance in combating zoonosis and reversal zoonosis linked with COVID-19. This article provides a brief overview on Omicron variant, its recently emerging lineages and subvairants with a special focus on BF.7 and XBB.1.5 as much more infectious and highly transmissible variations that may once again threaten a sharp increase in COVID-19 cases globally amid the currently ongoing pandemic, along with presenting salient mitigation measures. © 2022, Editorial board of Journal of Experimental Biology and Agricultural Sciences. All rights reserved.

Synthesis, structural investigations, XRD, DFT, anticancer and molecular docking study of a series of thiazole based Schiff base metal complexes

A novel Schiff base (SB) ligand, abbreviated as HDMPM, resulted from the condensation of 2-amino-4 -phenyl-5-methyl thiazole and 4-(diethylamino)salicyaldehyde, and its metal complexes with [Co(II), Cu(II), Ni(II), and Zn(II)] ions in high yield were formed. The physico-chemical techniques such as elemental analysis, molar conductance, IR, 1 H and 13 C NMR, mass spectroscopy, and electronic absorption studies were utilized to characterize the synthesized compounds. The studied compounds were examined for their possible anticancer activity against a number of human cancerous cell lines, including A549 lung carcinoma, HepG2 liver cancer, HCT116 colorectal cancer, and MCF-7 breast cancer cell lines, with dox-orubicin serving as the standard. The study revealed that Zn(II) complex showed significant activity to inhibit growth of HepG2, MCF7, A549, and HCT116 cell lines by a factor of 88, 70, 75, and 70, respec-tively, when compared to untreated. In addition, the reported compounds were optimized by employing Gaussian16 program package with B3LYP functional incorporating dispersion with two different basis sets (LanL2DZ and 6-31G(d,p)). Moreover, Autodock Vina software was used to assess the biological effective-ness of the studied compounds against SARS-CoV-2 Omicron variant (PDB ID: 7T9K).(c) 2022 Elsevier B.V. All rights reserved.

Targeting Omicron (B.1.1.529) SARS CoV-2 spike protein with selected phytochemicals: an in-silico approach for identification of potential drug

Severe acute respiratory syndrome coronavirus-2 (S ARS-CoV-2) emerging variants particularly those of concern contain numerous mutations that influence the behavior and transmissibility of the virus and could adversely affect the efficacies of existing coronavirus disease 2019 (COVID-19) vaccines and immunotherapies. The emerging SARS-CoV-2 variants have resulted in different waves of the pandemic within the ongoing COVID-19 pandemic. On 26 November 2021 World Health Organization designated omicron (B.1.1.529) as the fifth variant of concern which was first reported from South Africa on November 24, 2021, and thereafter rapidly spread across the globe owing to its very high transmission rates along with impeding efficacies of existing vaccines and immunotherapies. Omicron contains more than 50 mutations with many mutations (26-32) in spike protein that might be associated with high transmissibility. Natural compounds particularly phytochemicals have been used since ancient times for the treatment of different diseases, and owing to their potent anti-viral properties have also been explored recently against COVID-19. In the present study, molecular docking of nine phytochemicals (Oleocanthal, Tangeritin, Coumarin, Malvidin, Glycitein, Piceatannol, Pinosylnin, Daidzein, and Naringenin) with omicron spike protein (7QNW (electron microscopy, resolution 2.40 Å) was done. The docking study revealed that selected ligands interact with the receptor with binding energy in the range of-6.2 to-7.0 kcal/mol. Pinosylnin showed the highest binding energy of-7.0 kcal/mol which may be used as potential ligands against omicron spike protein. Based on the docking studies, it was suggested that these phytochemicals are potential molecules to be tested against omicron SARS-CoV-2 and can be used to develop effective antiviral drugs. © 2022, Editorial board of Journal of Experimental Biology and Agricultural Sciences. All rights reserved.

Consecutive Hits of COVID-19 in India: The Mystery of Plummeting Cases and Current Scenario.

The novel coronavirus disease 2019 (COVID-19)-related pandemic has been in existence for almost 2 years now after its possible emergence from a wet market in the city of Wuhan of the Chinese mainland. Evidence of the emergence and transmission of this virus was attributed to bats and pangolins. The causative virus, severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2), has rapidly spread globally, affecting humans considerably with its current death toll to be over 4.7 million out of more than 233 confirmed cases as of September 2021. The virus is constantly mutating and continuously trying to establish itself in humans by increasing its transmissibility and virulence through its numerous emerging variants. Several countries have been facing multiple waves of COVID-19 outbreaks one after the other, putting the medical and healthcare establishments under tremendous stress. Although very few drugs and vaccines have been approved for emergency use, their production capabilities need to meet the needs of a huge global population. Currently, not even a quarter of the world population is vaccinated. The situation in India has worsened during the ongoing second wave with the involvement of virus variants with a rapid and huge surge in COVID-19 cases, where the scarcity of hospital infrastructure, antiviral agents, and oxygen has led to increased deaths. Recently, increased surveillance and monitoring, strengthening of medical facilities, campaigns of awareness programs, progressive vaccination drive, and high collaborative efforts have led to limiting the surge of COVID-19 cases in India to a low level. This review outlines the global status of the pandemic with special reference to the Indian scenario.

SPECTRAL CHARACTERIZATION AND BIOLOGICAL STUDIES OF SOME TERNARY COMPLEXES WITH MOLECULAR DOCKING INVESTIGATIONS AGAINST MERS AND SARS TYPE CORONAVIRUSES

A series of ternary complexes with a Schiff base (HL1) derived from 2-hydrazinobenzimidazole and o-hydroxybenzophenone (primary ligand) have been prepared. Here, 1,10-phenanthroline acts as secondary ligand (L2). These metal complexes were investigated by UV-Vis, IR, H-1 NMR and thermal techniques. The spectral data confirmed tridentate nature of the SB ligand with NNO type coordination, whereas the secondary ligand L2 (1,10-phenanthroline) coordinated through its two nitrogen atoms (NN type). These compounds possess distorted octahedral geometry. Moreover, these compounds were screened against B. subtilis and E. coli to evaluate their antibacterial activity. In addition, molecular docking studies were performed against MERS-CoV and SARS-CoV-2 main protease (Mpro). Moreover, DFT calculations and QSAR studies of the SB ligand were also performed.

Comparative pathology, molecular pathogenicity, immunological features, and genetic characterization of three highly pathogenic human coronaviruses (MERS-CoV, SARS-CoV, and SARS-CoV-2).

The last two decades have witnessed the emergence of three deadly coronaviruses (CoVs) in humans: severe acute respiratory syndrome coronavirus (SARS-CoV), Middle East respiratory syndrome coronavirus (MERS-CoV), and severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). There are still no reliable and efficient therapeutics to manage the devastating consequences of these CoVs. Of these, SARS-CoV-2, the cause of the currently ongoing coronavirus disease 2019 (COVID-19) pandemic, has posed great global health concerns. The COVID-19 pandemic has resulted in an unprecedented crisis with devastating socio-economic and health impacts worldwide. This highlights the fact that CoVs continue to evolve and have the genetic flexibility to become highly pathogenic in humans and other mammals. SARS-CoV-2 carries a high genetic homology to the previously identified CoV (SARS-CoV), and the immunological and pathogenic characteristics of SARS-CoV-2, SARS-CoV, and MERS contain key similarities and differences that can guide therapy and management. This review presents salient and updated information on comparative pathology, molecular pathogenicity, immunological features, and genetic characterization of SARS-CoV, MERS-CoV, and SARS-CoV-2; this can help in the design of more effective vaccines and therapeutics for countering these pathogenic CoVs.

Negative and positive environmental perspective of COVID-19: air, water, wastewater, forest, and noise quality

The ongoing coronavirus disease 2019 (COVID-19) pandemic driven by severe acute respiratory syndrome coronavirus–2 (SARS-CoV-2) has become the most critical universal health disaster of this century. Millions of people are staying at home obeying lockdown to halt the spread of this novel virus. The spread of the virus has forced people to use the mask, gloves, hand sanitizer, etc. daily, and healthcare workers to use personal protection equipment following the WHO guidelines, resulting in huge amounts of medical waste. This pandemic has led to a slowdown of economic activities significantly, and consequently, stock markets have nosedived beyond speculation. Although the deadly coronavirus has taken away millions of precious lives and the livelihood of many sections of people worldwide, it has brought several positive changes in the world. Furthermore, it has led to a massive restoration of the environment and improved air and water quality. Pandemic showed the resilient nature of the environment, including air and water, when human activities are paused. In addition, we also discussed how this pandemic affects human lifestyle behavior. © 2021 The Author(s). Published by Informa UK Limited, trading as Taylor & Francis Group.

Modulation of host epigenome by coronavirus infections and developing treatment modalities for COVID-19 beyond genetics.

The recent Severe Acute Respiratory Syndrome Coronavirus-2 (SARS-CoV-2) outbreak has resulted in coronavirus disease 2019 (COVID-19) pandemic worldwide, affecting millions of lives. Although vaccines are presently made available, and vaccination drive is in progress to immunize a larger population; still the risk of SARS-CoV-2 infection and related mortality is persistent amid threats of the third wave of the ongoing pandemic. In the scenario of unavailability of robust and efficient treatment modalities, it becomes essential to understand the mechanism of action of the virus and deeply study the molecular mechanisms (both at the virus level and the host level) underlying the infection processes. Recent studies have shown that coronaviruses (CoVs) cause-specific epigenetic changes in the host cells to create a conducive microenvironment for replicating, assembling, and spreading. Epigenetic mechanisms can contribute to various aspects of the SARS-CoV-2 multiplication cycle, like expressing cytokine genes, viral receptor ACE2, and implicating different histone modifications. For SARS-CoV-2 infection, viral proteins are physically associated with various host proteins resulting in numerous interactions between epigenetic enzymes (i.e., histone deacetylases, bromodomain-containing proteins). The involvement of epigenetic mechanisms in the virus life cycle and the host immune responses to control infection result in epigenetic factors recognized as emerging prognostic COVID-19 biomarkers and epigenetic modulators as robust therapeutic targets to curb COVID-19. Therefore, this narrative review aimed to summarize and discuss the various epigenetic mechanisms that control gene expression and how these mechanisms are altered in the host cells during coronavirus infection. We also discuss the opportunities to exploit these epigenetic changes as therapeutic targets for SARS-CoV-2 infection. Epigenetic alterations and regulation play a pivotal role at various levels of coronavirus infection: entry, replication/transcription, and the process of maturation of viral proteins. Coronaviruses modulate the host epigenome to escape the host immune mechanisms. Therefore, host epigenetic alterations induced by CoVs can be considered to develop targeted therapies for COVID-19.

Blood scarcity at the blood banks during COVID-19 pandemic and strategies to promote blood donations: current knowledge and futuristic vision

The course of the coronavirus disease (COVID-19) pandemic has significantly affected the healthcare systems in multiple ways, the programs of control and the management of patients with other infectious diseases as well as with chronic and acute non-communicable diseases, including those conditions requiring blood transfusions. Blood donations have been decreasing over time in multiple countries with their expected consequences. Although the spread of SARS-CoV-2 has not been detected via blood transfusion, the increasing fear and anxiety among communities have led to a substantial decrease in blood donations. Several research groups have raised concerns about the consequences associated with the scarcity of blood. However, it is critical to understand the underlying causes of the sharp decline in blood donations, as well as the consequences. Hence, we discuss the impact of blood scarcity at the blood banks during the COVID-19 pandemic as well as strategies to promote blood donations, given the experience in some countries with this situation. © 2021 The Author(s). Published by Informa UK Limited, trading as Taylor & Francis Group.

An efficient synthesis towards the core of Crinipellin: TD-DFT and docking studies

In this present report, we are describing a novel route for the synthesis of the tetracyclic ring systems, a common core of crinipellin, via oxidative dearomatization, cycloaddition and oxa- di-pi-methane rearrangement. We are also concerned to explore a route to tetracyclic core (1e) of Crinipellin and tricyclic core (1g) of Allicaol B through intermolecular diels alder reaction and photochemically 1,2 acyl shift. Moreover, docking study of compound 13 and 16 is investigated against AcrB multidrug efflux pump of Escherichia coli (PDB ID: 1T9U), main protease of SARS COV-2 (PDB ID: 6W63), DNA gyrase of Streptococcus pneumonia (PDB ID: 4Z2C), human estrogen receptor alpha (PDB ID: 3ERT), human lanosterol 14-alpha-demethylase (CYP51)(PDB ID: 3JUS) and cyclooxygenase-2 (Prostaglandin Synthase-2) (PDB ID: 1CX2). The obtained results are important for the exploitation of the therapeutic potential of these derivatives as antimicrobial, antiviral, anticancer, antifungal or anti-inflammatory agents. In addition, TD-DFT studies of the compounds are also carried out. © 2021 The Author(s)

Synthesis and physicochemical studies of a series of mixed-ligand transition metal complexes and their molecular docking investigations against Coronavirus main protease

A novel series of mixed-ligand complexes of the type, [M(L-1)(L-2)Cl]center dot 2H(2)O [L-1 = 2-(alpha-methyl salicylidene hydrazine) benzimidazole (primary ligand), L-2 = 2,2'-bipyridine (bipy;secondary ligand), M = Co(n), Ni(n), Cu(n) and Zn(n)], were based on the physicoanalytical studies. The spectroscopic findings revealed tridentate nature of the Schiff base ligand (L-1) and its coordination to the metal ions via azomethine nitrogen, ring nitrogen and the deprotonated phenolic oxygen atoms. Furthermore, the synthesized compounds were evaluated for antimicrobial activity against Bacillus subtilis, Escherichia coli and Salmonella typhi microorganisms. In addition, molecular docking studies were carried out against Middle East respiratory syndrome coronavirus (PDB ID: 4ZS6) and severe acute respiratory syndrome coronavirus 2 main protease (PDB ID: 6W63).