SARS-CoV-2 transmissibility is higher than that of other human coronaviruses; therefore, it poses a threat to the populated communities. We investigated mutations among envelope (E), membrane (M), and spike (S) proteins from different isolates of SARS-CoV-2 and plausible signaling influenced by mutated virus in a host. We procured updated protein sequences from the NCBI virus database. Mutations were analyzed in the retrieved sequences of the viral proteins through multiple sequence alignment. Additionally, the data was subjected to ScanPROSITE to analyse if the mutations generated a relevant sequence for host signaling. Unique mutations in E, M, and S proteins resulted in modification sites like PKC phosphorylation and N-myristoylation sites. Based on structural analysis, our study revealed that the D614G mutation in the S protein diminished the interaction with T859 and K854 of adjacent chains. Moreover, the S protein of SARS-CoV-2 consists of an Arg-Gly-Asp (RGD) tripeptide sequence, which could potentially interact with various members of integrin family receptors. RGD sequence in S protein might aid in the initial virus attachment. We speculated crucial host pathways which the mutated isolates of SARS-CoV-2 may alter like PKC, Src, and integrin mediated signaling pathways. PKC signaling is known to influence the caveosome/raft pathway which is critical for virus entry. Additionally, the myristoylated proteins might activate NF-κB, a master molecule of inflammation. Thus the mutations may contribute to the disease pathogenesis and distinct lung pathophysiological changes. Further the frequently occurring mutations in the protein can be studied for possible therapeutic interventions.

Coronavirus disease 2019 (COVID-19) caused by SARS-CoV2 is associated with various comorbidities; cardiovascular diseases, hypertension, diabetes, liver, lung diseases, and neurological ailments. The majority of the dysfunctions mentioned above are often associated with endothelial deterioration, indicating that endothelium can be the target of SARS-CoV2. Our study is an exclusive observational study that quantitatively analyses COVID-19 related comorbidities. We retrieved the data of % population of COVID-19 hospitalized and deceased patients with associated comorbidities from publicly accessible portals of the five European countries. A two tailed t-test enabled us to determine the significant proportions of deaths compared to hospitalized patients with associated comorbidity. Our study revealed that deaths associated with cardiovascular diseases and diabetes are highly significant (p < 0.0001) compared to hospitalized in countries like Italy, France, and Spain unlike the Netherlands. Deaths from kidney diseases (Italyp < 0.0001; Swedenp < 0.0001; Netherlandsp = 0.0001; Francep = 0.0033) and neurological ailments (Francep = 0.0001; Netherlandsp < 0.0001) are significantly higher than the total hospitalized patients affected by the particular comorbidity. We have noted that deaths due to liver diseases are least associated with COVID-19 among all comorbidities. Intriguingly, immunodeficiency shows mixed outcomes in death proportions compared to the hospital admitted individuals. Besides, the treatment regime involves drugs like losartan, ACE inhibitors, angiotensin-receptor blockers, Remdesivir, Chloroquine, Hydroxychloroquine, etc. may modulate the severity of the comorbidities. These comorbidities can create chaos in the existing healthcare system and may worsen the disease outcome.

Smoking a cigarette generates over 4000 chemicals that have a deleterious impact on each part of the human body. It produces three main severe effects on the liver organ: oncogenic, immunological, and indirect or direct toxic effects. It results in the production of cytotoxic substances, which raises fibrosis and necro-inflammation. Additionally, it also directs the production of pro-inflammatory cytokines tumour necrosis factor alfa (TNF-α) and interleukins (IL-1β, IL-6) that will be responsible for the chronic liver injury. Furthermore, it gives rise to secondary polycythemia and successively raises the turnover and mass of red cells, which might be a common factor responsible for the development of oxidative stress in the liver due to iron overload. It also produces chemicals that are having oncogenic properties and raises the risk of liver cancer especially in sufferers of chronic hepatitis C. Smoking modulates both humoral and cell-mediated responses by restricting the proliferation of lymphocytes and inducing their apoptosis and ultimately decreasing the surveillance of cancer cells. Moreover, it has been determined that heavy smoking impacts the response of hepatitis C patients to interferon (IFN) therapy through different mechanisms, which can be improved by phlebotomy. Efforts are being made in different nations in decreasing the prevalence of smoking to improve premature death and ill effects of their nation’s individuals.

The pandemic of novel coronavirus disease (COVID-19) caused by the Severe Respiratory Syndrome Coronavirus-2 (SARS-CoV-2) creates an immense menace to public health worldwide. Currently, the World Health Organization (WHO) has recognized the novel coronavirus as the main cause of global pandemic. Patients infected with this virus generally show fever, nausea, and respiratory illness, while some patients also manifest gastrointestinal symptoms such as abdominal pain, vomiting, and diarrhea. Traces of SARS-CoV-2 RNA have been found in gastrointestinal cells. Further angiotensin converting enzyme 2 (ACE2) the known receptor for the virus is extensively expressed in these cells. This implies that gastrointestinal tract can be infected and can also present them as a replication site for SARS-CoV-2, but since this infection may lead to multiple organ failure, therefore identification of another receptor is a plausible choice. This review aims to provide comprehensive information about probable receptors such as sialic acid and CD147 which may facilitate the virus entry. Several potential targets are mentioned which can be used as a therapeutic approach for COVID-19 and associated GI disorders. The gut microbiomes are responsible for high levels of interferon-gamma which causes hyper-inflammation and exacerbates the severity of the disease. Briefly, this article highlights the gut microbiome’s relation and provides potential diagnostic approaches like RDT and LC-MS for sensitive and specific identification of viral proteins. Altogether, this article reviews epidemiology, probable receptors and put forward the tentative ideas of the therapeutic targets and diagnostic methods for COVID-19 with gastrointestinal aspect of disease.

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N-nitroso compounds (NOC) are produced by the acid catalyzed reaction of nitrite with certain nitrogen compounds. The gastrointestinal tract (GI) is the main site for the formation of reactive nitrogen species (RNS). Bacteria present on the GI tract surface reduced the dietary nitrate or nitrite into Nitric oxide NO and other related compounds. The clinical sign of NOC carcinogenicity varies according to species, dose, and route of administration. Humans are exposed to preformed N-nitroso compounds and endogenous NOC via the environmental food chain. Several NOC are potential human carcinogens, including DENA and NDMA, but evidence from population studies is inconsistent.

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