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The life cycle of SARS-CoV and MERS-CoV in host cells. SARS-CoV and MERS-CoV enter target cells through an endosomal pathway. The S proteins of SARS and MERS bind to cellular receptor angiotensin-converting enzyme 2 (ACE2) and cellular receptor dipeptidyl peptidase 4 (DPP4), respectively. Following entry of the virus into the host cell, the viral RNA is unveiled in the cytoplasm. ORF1a and ORF1ab are translated to produce pp1a and pp1ab polyproteins, which are cleaved by the proteases that are encoded by ORF1a to yield 16 non-structural proteins that form the RNA replicase-transcriptase complex. This complex drives the production of negative-sense RNAs [(−) RNA] through both replication and transcription. During replication, full-length (−) RNA copies of the genome are produced and used as templates for full-length (+) RNA genomes. During transcription, a subset of 7-9 sub-genomic RNAs, including those encoding all structural proteins, is produced through discontinuous transcription. Although the different sub-genomic mRNAs may contain several open reading frames (ORFs), only the first ORF (that closest to the 5′ end) is translated. Viral nucleocapsids are assembled from genomic RNA and N protein in the cytoplasm, followed by budding into the lumen of the ERGIC (endoplasmic reticulum (ER)-Golgi intermediate compartment). Virions are then released from the infected cell through exocytosis. SARS-CoV, severe acute respiratory syndrome coronavirus; MERS-CoV, Middle East respiratory syndrome coronavirus; S, spike; E, envelope; M, membrane; N, nucleocapsid.

The life cycle of SARS-CoV and MERS-CoV in host cells. SARS-CoV and MERS-CoV enter target cells through an endosomal pathway. The S proteins of SARS and MERS bind to cellular receptor angiotensin-converting enzyme 2 (ACE2) and cellular receptor dipeptidyl peptidase 4 (DPP4), respectively. Following entry of the virus into the host cell, the viral RNA is unveiled in the cytoplasm. ORF1a and ORF1ab are translated to produce pp1a and pp1ab polyproteins, which are cleaved by the proteases that are encoded by ORF1a to yield 16 non-structural proteins that form the RNA replicase-transcriptase complex. This complex drives the production of negative-sense RNAs [(−) RNA] through both replication and transcription. During replication, full-length (−) RNA copies of the genome are produced and used as templates for full-length (+) RNA genomes. During transcription, a subset of 7-9 sub-genomic RNAs, including those encoding all structural proteins, is produced through discontinuous transcription. Although the different sub-genomic mRNAs may contain several open reading frames (ORFs), only the first ORF (that closest to the 5′ end) is translated. Viral nucleocapsids are assembled from genomic RNA and N protein in the cytoplasm, followed by budding into the lumen of the ERGIC (endoplasmic reticulum (ER)-Golgi intermediate compartment). Virions are then released from the infected cell through exocytosis. SARS-CoV, severe acute respiratory syndrome coronavirus; MERS-CoV, Middle East respiratory syndrome coronavirus; S, spike; E, envelope; M, membrane; N, nucleocapsid.

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Coronaviruses (CoVs) have formerly been regarded as relatively harmless respiratory pathogens to humans. However, two outbreaks of severe respiratory tract infection, caused by the severe acute respiratory syndrome coronavirus (SARS-CoV) and the Middle East respiratory syndrome coronavirus (MERS-CoV), as a result of zoonotic CoVs crossing the speci...

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... SARS and MERS cause severe pneumonia resulting from these novel coronaviruses, sharing some similarities in their pathogenesis (Figure 2) [28]. ...
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... SARS and MERS cause severe pneumonia resulting from these novel coronaviruses, sharing some similarities in their pathogenesis (Figure 2) [28]. ...
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... MERS-CoV infection of humans, the primary receptor is a multifunctional cell surface protein, dipeptidyl peptidase 4 (DPP4, also known as CD26) [36], which is widely expressed on epithelial cells in the kidney, alveoli, small intestine, liver, and prostate, and on activated leukocytes [37]. Consistent with this, MERS-CoV can infect several human cell lines, including lower respiratory, Figure 2. The life cycle of SARS-CoV and MERS-CoV in host cells. ...

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... There is a chance for quick vaccine development because the genomic and structural information on SARS-CoV-2 has become available much faster than that on other HCoVs [28,45,54,55]. Additionally, information gathered from research on SARS-CoV and MERS-CoV vaccine development is useful for creating a vaccine candidate for SARS-CoV-2 [56,57]. ...
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Coronavirus, a causative agent of the common cold to a much more complicated disease such as “severe acute respiratory syndrome (SARS-CoV-2), Middle East Respiratory Syndrome (MERS-CoV-2), and Coronavirus Disease 2019 (COVID-19)”, is a member of the coronaviridae family and contains a positive-sense single-stranded RNA of 26–32 kilobase pairs. COVID-19 has shown very high mortality and morbidity and imparted a significantly impacted socioeconomic status. There are many variants of SARS-CoV-2 that have originated from the mutation of the genetic material of the original coronavirus. This has raised the demand for efficient treatment/therapy to manage newly emerged SARS-CoV-2 infections successfully. However, different types of vaccines have been developed and administered to patients but need more attention because COVID-19 is not under complete control. In this article, currently developed nanotechnology-based vaccines are explored, such as inactivated virus vaccines, mRNA-based vaccines, DNA-based vaccines, S-protein-based vaccines, virus-vectored vaccines, etc. One of the important aspects of vaccines is their administration inside the host body wherein nanotechnology can play a very crucial role. Currently, more than 26 nanotechnology-based COVID-19 vaccine candidates are in various phases of clinical trials. Nanotechnology is one of the growing fields in drug discovery and drug delivery that can also be used for the tackling of coronavirus. Nanotechnology can be used in various ways to design and develop tools and strategies for detection, diagnosis, and therapeutic and vaccine development to protect against COVID-19. The design of instruments for speedy, precise, and sensitive diagnosis, the fabrication of potent sanitizers, the delivery of extracellular antigenic components or mRNA-based vaccines into human tissues, and the administration of antiretroviral medicines into the organism are nanotechnology-based strategies for COVID-19 management. Herein, we discuss the application of nanotechnology in COVID-19 vaccine development and the challenges and opportunities in this approach.
... The virus was originally discovered in Wuhan, China, in late December 2019 (Chen et al. 2020a, b;Zhou et al. 2020) and has now spread rapidly to all continents and all parts of the world. The recent SARS-CoV-2 is genetically distant from the previous coronaviruses, Middle East Respiratory Syndrome Coronavirus (MERS-CoV) and Severe Acute Respiratory Syndrome Coronavirus (SARS-CoV) (Song et al. 2019). This newly identified coronavirus is known to be transmitted through direct contact, contaminated fomites and aerosolised respiratory fluids (Peng et al. 2020;Zaid et al. 2020). ...
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Wastewater monitoring for SARS-CoV-2 has attracted considerable attention worldwide to complement the existing clinical-based surveillance system. In this study, we report our first successful attempt to prove the circulation of SARS-CoV-2 genes in Malaysian urban wastewater. A total of 18 wastewater samples were obtained from a regional sewage treatment plant that received municipal sewage between February 2021 and May 2021. Using the quantitative PCR assay targeting the E and RdRp genes of SARS-CoV-2, we confirmed that both genes were detected in the raw sewage, while no viral RNA was found in the treated sewage. We were also able to show that the trend of COVID-19 cases in Kuala Lumpur and Selangor was related to the changes in SARS-CoV-2 RNA levels in the wastewater samples. Overall, our study highlights that monitoring wastewater for SARS-CoV-2 should help local health professionals to obtain additional information on the rapid and silent circulation of infectious agents in communities at the regional level.
... The proteins include the spike protein (S) which is the point of attachment to the host Angiotensin Converting Enzyme (ACE) [20]. The envelope protein (E), membrane protein (M), and nucleocapsid proteins (N) are involved in viral assembly and RNA synthesis [11,21] (Fig. 1). Many strategies have been proposed to curtail the survival of the virus in the host cell. ...
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Concerned organizations and individuals are fully engaged in seeking appropriate measures towards managing Severe Acute Respiratory Syndrome Coronavirus 2 (SAR-CoV-2) infection because of the unprecedented economic and health impact. SAR-CoV-2 Main protease (SARS-CoV-2 Mpro) is unique to the survival and viability of the virus. Therefore, inhibition of Mpro can block the viral propagation. Thirty (30) derivatives were built by changing the glucosides in the Meta and para position of quercetin and isohamnetin. Molecular docking analysis was used for the screening of the compounds. Dynamics simulation was performed to assess the stability of the best pose docked complex. Molecular mechanics binding free energy calculation was done by Molecular Mechanics/Poisson-Boltzmann Surface Area (MMPBSA). Overall analysis showed that the compounds are allosteric inhibitors of SARS-CoV-2 Mpro. Dynamic simulation analysis established the stability of Mpro-ISM-1, Mpro-ISD-3, Mpro-IST-2, Mpro-QM-2, and Mpro-QD-6 complexes with a maximum of 7 hydrogen bonds involved in their interaction. The MMPBSA binding free energies for ISM-1, ISD-3, IST-2, QM-2, and QD-6 were −92.47 ± 9.06, −222.27 ± 32.5, 180.72 ± 47.92, 156.46 ± 49.88 and −93.52 ± 48.75 kcal/mol respectively. All the compounds showed good pharmacokinetic properties, while only ISM-1 inhibits hERG and might be cardio-toxic. Observations in this study established that the glucoside position indeed influenced the affinity for SARS-CoV-2 Mpro. The study also suggested the potentials of ISD-3, QM-2 and QD-6 as potent inhibitors of the main protease, further experimental and clinical studies are however necessary to validate and establish the need for further drug development processes. Therefore, future studies will be on the chemical synthesis of the compounds and investigation of the in-vitro inhibition of SARS-CoV-2.
... To bind and mediates subsequent fusion between the envelope and host cell membranes, it uses angiotensin-converting enzyme 2 (ACE2) receptor to aid viral entry into the host cell [17,18] Human coronaviruses aand b-CoVs infect only mammals and animals while gand d-CoVs, infect birds and mammals [19][20][21]. The HCoV-229E and HCoV-NL63 are a-CoVs; whereas HCoV-OC43, HCoV-HKU1, SARS-CoV, MERS-C-oV and SARS-CoV are b-CoVs [22]. SARS-CoV-2 outbreak started in the Guangdong Province, China in November 2002, causing severe pneumonia within days of infection [23], it is highly contagious and spread to 29 countries, WHO reported that there were 8098 patients and 774 deaths during outbreak with a mortality rate of 9.56% [24]. ...
... Hypothesis said SARS-CoV spike can mediate cell-cell fusion with ACE2-expressing cells and this may be confirmed by the experiment announced that when ACE2 is expressed on the cell surface and cleaved by exogenous proteases favoring the entrance of the virus into the host cell [27]. The E protein is required for virus endocytosis and assembly, the M protein is necessary for viral assembly and morphogenesis, and the N protein is required for RNA synthesis [22]. ...
Article
Background and aim: In early December 2019 started coronavirus disease 2019 (COVID-19) pandemic in China by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection which transmitted from bats to humans. According to WHO, there are more than two hundred million confirmed cases of COVID-19 including more than seven million deaths, so we desperately need to discover an effective treatment to eliminate SARS-CoV-2 infection permanently. One of the most promising technologies for the treatment of COVID-19 is Nanotechnology. Herein we tried to summarize usages of nanotechnology in fighting of COVID-19 and to focus on the challenges, advantages, and disadvantages of the application of this technology. Methods: Searching of PubMed, SCOPUS and Google scholar by using a specific search strategy ‘‘(COVID 19 OR COVID-19 Virus Disease OR COVID 19 Virus Infection OR 2019-nCoV Infection OR Coronavirus Disease-19 OR 2019 Novel Coronavirus Infection OR SARS-CoV-2 Infection OR COVID-19 Pandemic) AND nanotechnology. Results and Conclusions: Nanotechnology can be used in treatment, diagnosis and prevention of COVID-19. Many nanoparticle types can be used in treatment of COVID�19 such as polymers, dendrimers and quantum dots. In addition to these types of nanoparticles, there is Nan bot used for carrying out localized drug delivery and can be controlled by a user. We can also use quantum dots, metal and magnetic nanoparticles for the diagnosis of COVID-19 to increase the efficiency of diagnostic tests. Regarding to COVID-19 prevention, nanoparticles are used for the manufacture of nano-masks and vaccines such as: Oxford/AstraZeneca, Cansino, Moderna and Biotech/Pfizer vaccines. Each technology has advantages and disadvantages. Challenges remain in the domain for its application due to lack of knowledge.
... A second outbreak began in 2012 in Saudi Arabia. An outbreak of a novel strain of coronavirus started on December 31 of 2019, leading to severe illness, known as SARS-CoV-2 or nCOVID-19and killing many people with very rapid and easy spread with high infectivity rate by many routes [1]. The WHO announced COVID-19 illnessto be a global pandemic On 11 March [2]. ...
... High mutation rate in Coronaviridae family produce Coronaviruses (CoV) which belong to the beta-coronavirus leading to illnesses with variable severity. In China in 2003, a severe acute respiratory syndrome (SARS)leading to death of a number of people spread rapidly and highly infectious by different routes [1]. On 11 March,the WHO announced COVID-19 illness a global pandemic [2]. ...
... The 2019-nCoV genome contains 14 ORFs encoding 27 proteins. The 3′ end contains four ORFs that encode structural proteins (S, E, M, and N) and eight ORFs that encode accessory proteins (ORF3a, 3b, P6, 7a, 7b, 8b, 9b, and ORF14) [15,16]. ORF3a is a conservative coronavirus protein that contains different functional domains related to virulence, infectivity, and virus release [17]. ...
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Intestinal microecology is composed of bacteria, fungi and viruses. As a part of intestinal microecology, viruses participate in the occurrence and development of colorectal cancer. The 2019-nCoV was detected in stool samples from patients during COVID-19, suggesting that the 2019-nCoV may be associated with intestinal microecology. However, the relationship of the 2019-nCoV and CRC is unclear. The aim of this study is to explore the role of Open Reading Frame-3a (ORF3a) of the 2019-nCoV in CRC. After the pCDH-CMV-MCS-EF1-Puro vector that provides high expression of ORF3a was transfected into the SW480 CRC cell line, immunofluorescence was used to determine the localization of ORF3a in SW480 cells. The proliferation, migration, invasion, apoptosis, and cell cycle progression of SW480 cells were measured using the Cell Counting Kit-8 (CCK-8), wound healing, Transwell assay, flow cytometry, the TUNEL assay, and propidium iodide single staining. The results showed that ORF3a inhibited the proliferation, invasion, and migration of SW480 cells and induced their apoptosis after 24, 48, 72 h. Meanwhile, ORF3a inhibited the cell cycle and blocked SW480 CRC cells in the G1 phase. In in vivo experiments, high ORF3a expression was associated with decreased tumor volume, tumor weight, relative tumor volume, and tumor activity. ORF3a inhibited the growth and induced apoptosis and necrosis of tumor tissues. Based on this, we demonstrated that ORF3a might play a role in CRC, providing a new direction for the prevention and treatment of CRC.
... These viruses cause mild to severe respiratory and intestinal infections in immune-compromised individuals. They were not considered to be pathogenic until the outbreak of Severe Acute Respiratory Syndrome (SARS) in China and the Middle East Respiratory Syndrome Coronavirus (MERS-CoV) in Middle East countries in 2002 and 2012 respectively when the viral infection led to significant deaths among the infected individual's (Song et al., 2019). As on 24 September 2022, the SARS-CoV-2 pandemic has resulted in more than 611 million infections resulting in 6.5 million deaths globally (https:// covid19.who.int/). ...
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The recent pandemic caused by Severe Acute Respiratory Syndrome Coronavirus-2 has resulted in enormous deaths around the world. Clues from genomic sequences of parent and their mutants can be obtained to understand the evolving pathogenesis of this virus. Apart from the viral proteins, virus-encoded microRNAs (miRNAs) have been shown to play a vital role in regulating viral pathogenesis. Thus we sought to investigate the miRNAs encoded by SARS-CoV-2, its mutants, and the host. Here, we present the results obtained using a dual approach i.e (i) identifying host-encoded miRNAs that might regulate viral pathogenesis and (ii) identifying viral-encoded miRNAs that might regulate host cell signaling pathways and aid in viral pathogenesis. Analysis utilizing the first approach resulted in the identification of ten host-encoded miRNAs that could target the SARS, SARS-CoV-2, and its mutants. Interestingly our analysis revealed that there is a significantly higher number of host miRNAs that could target the SARS-CoV-2 genome as compared to the SARS reference genome. Results from the second approach resulted in the identification of a set of virus-encoded miRNAs which might regulate host signaling pathways. Our analysis further identified a similar “GA” rich motif in the SARS-CoV-2 and its mutant genomes that was shown to play a vital role in lung pathogenesis during severe SARS infections. In summary, we have identified human and virus-encoded miRNAs that might regulate the pathogenesis of SARS coronaviruses and describe similar non-coding RNA sequences in SARS-CoV-2 that were shown to regulate SARS-induced lung pathology in mice.
... CoVs genome is a non-segmented, positive sense, single-stranded RNA genome. It is the longest (26.4-32.0 kb) among all known RNA viruses [16][17][18]. The genome is flanked by two untranslated regions (UTRs) and was predicted to have around 14 ORFs with more than 25 proteins. ...
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With the emergence of SARS-CoV-2, routine surveillance combined with sequence and phylogenetic analysis of coronaviruses is urgently required. In the current study, the four common human coronaviruses (HCoVs), OC43, NL63, HKU1, and 229E, were screened in 361 clinical samples collected from hospitalized children with respiratory symptoms during four winter seasons. RT-PCR-based detection and typing revealed different prevalence rates of HCoVs across the four seasons. Interestingly, none of the four HCoVs were detected in the samples (n = 100) collected during the winter season of the COVID-19 pandemic. HCoV-OC43 (4.15%) was the most frequently detected, followed by 229E (1.1%). Partial sequences of S and N genes of OC43 from the winter seasons of 2015/2016 and 2021/2022 were used for sequence and phylogenetic analysis. Multiple sequence alignment of the two Saudi OC43s strains with international strains revealed the presence of sequence deletions and several mutations, of which some changed their corresponding amino acids. Glycosylation profiles revealed a number of O-and N-glycosylation sites in both genes. Based on phylogenetic analysis, four genotypes were observed with Riyadh strains grouped into the genotype C. Further long-term surveillance with a large number of clinical samples and sequences is necessary to resolve the circulation patterns and evolutionary kinetics of OC43 in Saudi Arabia.
... SD -Standard deviation depression among college students during this confinement whose family members/relatives/friends are diagnosed with COVID-19. [25] There is documentation from studies by Cao et al. [7] and Mangalesh et al. [26] investigating the mental health status of students which assessed that lagging behind in studies was significantly associated with depressive symptoms in students, in line with the results of the present study. Due to sustained closure of colleges, students might have thought that online classes could not accomplish their prerequisites. ...
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Background: Subject of interest is the status of mental health of college students around the globe as they are undergoing a lot of mental stress and depression during the pandemic lockdown. Aims and Objectives: The aim of this survey is to evaluate the prevalence of depression, its determinants, and association with coping mechanisms among college students during the COVID‑19 pandemic lockdown. Methodology: A cross‑sectional, questionnaire‑based e‑survey among college students in North India using Snowball sampling technique was done. A total of 920 responses (calculated sample size) were collected for a period of 25 days from 6th to 30th October 2020. A questionnaire regarding sociodemographic characteristics, COVID‑19‑related experiences along with Patient Health Questionnaire‑9 (PHQ‑9), and Carver Brief‑coping orientation to the problem experienced‑28 was adapted to Google Forms and distributed to college students. Chi‑square test, independent t‑test, Pearson’s correlation, and hierarchical multiple regression analysis were used to investigate the determinants of depression and its association with coping mechanisms. Results: On analysis of 884 qualified participants, it was revealed that 402 (45.5%) participants have depressive symptoms ranging from moderate to severe level. The mean score of PHQ‑9 was 9.82 ± 6.61. Nearly 85% thought that they were lagging behind in studies. The main determinants of depression in this study were age group of 21–24 years thought of lagging behind in studies and family members/friends/relatives diagnosed with COVID‑19. Adaptive coping mechanisms (emotional support, religion, and humor) were significantly associated with lower depressive symptoms and maladaptive coping mechanisms (self‑distraction, denial, behavioral disengagement, and venting) were significantly associated with higher depressive symptoms among students. Conclusions: This survey revealed multiple determinants of depression, mainly including academic worries among college students. The college staff should provide a well‑structured pedagogical framework to encourage them and alleviate the unpleasant psychological effects of pandemic on students. Keywords: College students, coping mechanism, COVID‑19 lockdown, determinants, moderate to severe depressive symptoms