Coronavirus in Continuous Flux: From SARS-CoV to SARS-CoV-2

Electrochemical biosensor for sensitive detection of SARS-CoV-2 gene fragments using Bi2Se3 topological insulator

In this study, we have designed an electrochemical biosensor based on topological material Bi2Se3 for the sensitive detection of SARS-CoV-2 in the COVID-19 pandemic. Flake-shaped Bi2Se3 was obtained directly from high-quality single crystals using mechanical exfoliation, and the single-stranded DNA was immobilized onto it. Under optimal conditions, the peak current of the differential pulse voltammetry method exhibited a linear relationship with the logarithm of the concentration of target-complementary-stranded DNA, ranging from 1.0 × 10-15 to 1.0 × 10-11 M, with a detection limit of 3.46 × 10-16 M. The topological material Bi2Se3, with Dirac surface states, enhanced the signal-to-interference plus noise ratio of the electrochemical measurements, thereby improving the sensitivity of the sensor. Furthermore, the electrochemical sensor demonstrated excellent specificity in recognizing RNA. It can detect complementary RNA by amplifying and transcribing the initial DNA template, with an initial DNA template concentration ranging from 1.0 × 10-18 to 1.0 × 10-15 M. Furthermore, the sensor also effectively distinguished negative and positive results by detecting splitting-synthetic SARS-CoV-2 pseudovirus with a concentration of 1 copy/μL input. Our work underscores the immense potential of the electrochemical sensing platform based on the topological material Bi2Se3 in the detection of pathogens during the rapid spread of acute infectious diseases.

A ternary correlation multi-symptom network strategy based on in vivo chemical profile identification and metabolomics to explore the molecular basis of Ephedra herb against viral pneumonia

Ephedra herb (EH), an important medicine prescribed in herbal formulas by Traditional Chinese Medicine practitioners, has been widely used in the treatment of viral pneumonia in China. However, the molecular basis of EH in viral pneumonia remains unclear. In this study, a ternary correlation multi-symptom network strategy was established based on in vivo chemical profile identification and metabolomics to explore the molecular basis of EH against viral pneumonia. Results showed that 143 compounds of EH and 70 prototype components were identified in vivo. EH could reduce alveolar-capillary barrier disruption in rats with viral pneumonia and significantly downregulate the expression of inflammatory factors and bronchoalveolar lavage fluid. Plasma metabolomics revealed that EH may be involved in the regulation of arachidonic acid, tryptophan, tyrosine, nicotinate, and nicotinamide metabolism. The multi-symptom network showed that 12 compounds have an integral function in the treatment of viral pneumonia by intervening in many pathways related to viruses, immunity and inflammation, and lung injury. Further verification demonstrated that sinapic acid and frambinone can regulate the expression of related genes. It has been shown to be a promising representative of the pharmacological constituents of ephedra.

Risk factors for SARS-CoV-2 pneumonia among renal transplant recipients in Beijing Omicron wave

The novel coronavirus disease-19 had become an unprecedented global health emergency, quickly expanding worldwide. Omicron (B.1.1.529), as a novel variant of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), was initially identified in South Africa and Botswana. Renal transplant recipients (RTRs) are a special group and are more vulnerable to viral pneumonia. Thus, this study aimed to assess the incidence and risk factors of SARS-CoV-2 pneumonia that occurred in RTRs with Omicron infection. This single-center case-control study enrolled the RTRs who were diagnosed with SARS-CoV-2 infection by the SARS-CoV-2 nucleic acid test, which were divided into two groups according to the imaging features of SARS-CoV-2 pneumonia. The parameters were collected by questionnaires and analyzed using Statistical Product and Service Solutions. A total of 313 RTRs completed the questionnaires, and 131 were enrolled in this study with a mean age of 42.66 years. The incidence of SARS-CoV-2 pneumonia among the enrolled participants was 76.3%. The first symptoms included fever (89.3%), cough (93.1%), and expectoration (81.7%). From the comparison, the parameters such as age, gender, body mass index, lymphocyte count, and the percent of neutrophils and the basic serum creatinine before SARS-CoV-2 infection were significantly different between the two groups (P < 0.05). In multivariate analysis, age and the basic serum creatinine were independent risk factors for developing SARS-CoV-2 pneumonia (P < 0.05). Older RTRs with a high level of serum creatinine before SARS-CoV-2 infection were more at risk of developing SARS-CoV-2 pneumonia. More randomized controlled studies are needed.IMPORTANCEThis study aimed to assess the incidence and the risk factors of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) pneumonia that occurred in renal transplant recipients (RTRs) with Omicron infection. In conclusion, older RTRs with a high level of serum creatinine before SARS-CoV-2 infection were more at risk of developing SARS-CoV-2 pneumonia and should be timely treated, in case of severe pneumonia.

Hybridization-driven fluorometric platform based on metal-organic frameworks for the identification of the highly homologous viruses

A novel fluorometric strategy for the simultaneous identification of SARS-CoV-2 and SARS-CoV was successfully established based on a hybridization-induced signal on-off-on mechanism. Here, one part of the probe (P1) of SARS-CoV-2 (P = P1/P2) is partially related to SARS-CoV, while the other part (P2) is completely irrelevant to SARS-CoV. They as smart gatekeepers were anchored on NH₂-MIL-88(Fe) (MOF@P1/P2) to turn off its catalytic performance. Only the specific SARS-CoV-2 genetic target can strongly restore the peroxidase-like activity of MOF@P1/P2. In the presence of o-phenylenediamine, SARS-CoV-2 can be efficiently detected with high sensitivity, accuracy, and reliability. This strategy demonstrated excellent analytical characteristics with a linear range (10^-9 M ∼ 10^-6 M) under the limit of detection of 0.11 nM not only in buffer but also in 10 % serum, which partly shows its practicability. Most importantly, with the help of the auxiliary test of MOF@P1 and MOF@P2, SARS-CoV-2 and SARS-CoV can be efficiently quantified and distinguished. This novel strategy has provided a breakthrough in the development of such identification. In the whole process, only a simple one-step experiment was involved. This circumvents the trouble of pretreatment experiments in traditional methods, including complex enzymatic mixtures, specialized experimental equipment, many primers optimization as well as reverse transcriptase. Additionally, this novel strategy is rapid, low-cost, and easy-to-use tools.

A Detailed Overview of SARS-CoV-2 Omicron: Its Sub-Variants, Mutations and Pathophysiology, Clinical Characteristics, Immunological Landscape, Immune Escape, and Therapies

The COVID-19 pandemic has created significant concern for everyone. Recent data from many worldwide reports suggest that most infections are caused by the Omicron variant and its sub-lineages, dominating all the previously emerged variants. The numerous mutations in Omicron's viral genome and its sub-lineages attribute it a larger amount of viral fitness, owing to the alteration of the transmission and pathophysiology of the virus. With a rapid change to the viral structure, Omicron and its sub-variants, namely BA.1, BA.2, BA.3, BA.4, and BA.5, dominate the community with an ability to escape the neutralization efficiency induced by prior vaccination or infections. Similarly, several recombinant sub-variants of Omicron, namely XBB, XBD, and XBF, etc., have emerged, which a better understanding. This review mainly entails the changes to Omicron and its sub-lineages due to it having a higher number of mutations. The binding affinity, cellular entry, disease severity, infection rates, and most importantly, the immune evading potential of them are discussed in this review. A comparative analysis of the Delta variant and the other dominating variants that evolved before Omicron gives the readers an in-depth understanding of the landscape of Omicron's transmission and infection. Furthermore, this review discusses the range of neutralization abilities possessed by several approved antiviral therapeutic molecules and neutralizing antibodies which are functional against Omicron and its sub-variants. The rapid evolution of the sub-variants is causing infections, but the broader aspect of their transmission and neutralization has not been explored. Thus, the scientific community should adopt an elucidative approach to obtain a clear idea about the recently emerged sub-variants, including the recombinant variants, so that effective neutralization with vaccines and drugs can be achieved. This, in turn, will lead to a drop in the number of cases and, finally, an end to the pandemic.

SARS-CoV-2 Omicron variant: recent progress and future perspectives

Since the outbreak of the coronavirus disease 2019 (COVID-19) pandemic, there have been a few variants of the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), one of which is the Omicron variant (B.1.1.529). The Omicron variant is the most mutated SARS-CoV-2 variant, and its high transmissibility and immune evasion ability have raised global concerns. Owing to its enhanced transmissibility, Omicron has rapidly replaced Delta as the dominant variant in several regions. However, recent studies have shown that the Omicron variant exhibits reduced pathogenicity due to altered cell tropism. In addition, Omicron exhibits significant resistance to the neutralizing activity of vaccines, convalescent serum, and most antibody therapies. In the present review, recent advances in the molecular and clinical characteristics of the infectivity, pathogenicity, and immune evasion of Omicron variant was summarized, and potential therapeutic applications in response to Omicron infection were discussed. Furthermore, we highlighted potential response to future waves and strategies to end the pandemic.

Coronavirus disease 2019, allergic diseases, and allergen immunotherapy: Possible favorable mechanisms of interaction

Background: Both, allergen immunotherapy (AIT) and SARS-COV-2 infection cause a set of immunologic changes that respectively vary during the course of the treatment or the disease. Objective: To review immune changes brought along by each of these entities and how they might interrelate. Methods: We start presenting a brief review of the structure of the new coronavirus and how it alters the functioning of the human immune system. Subsequently, we describe the immune changes induced by AIT and how these changes could be favorable or unfavorable in the allergic patient infected with SARS-CoV-2 at a particular point of time during the evolving infection. Results: We describe how a healthy immune response against SARS-CoV-2 develops, versus an immune response that is initially suppressed by the virus, but ultimately overactivated, leading to an excessive production of cytokines (cytokine-storm-like). These changes are then linked to the clinical manifestations and outcomes of the patient. Reviewing the immune changes secondary to AIT, it becomes clear how AIT is capable of restoring a healthy innate immunity. Investigators have previously shown that the frequency of respiratory infections is reduced in allergic patients treated with AIT. On the other hand it also increases immunoregulation. Conclusion: As there are many variables involved, it is hard to predict how AIT could influence the allergic patient's reaction to a SARS-CoV-2 infection. In any case, AIT is likely to be beneficial for the patient with allergic rhinitis and/or allergic asthma in the context of the SARS-CoV-2 pandemic as controlling allergic diseases leads to a reduced need for contact with healthcare professionals. The authors remind the reader that everything in this article is still theoretical, since at the moment, there are no published clinical trials on the outcome of COVID-19 in allergic patients under AIT.

Lung Protection vs. Infection Resolution: Interleukin 10 Suspected of Double-Dealing in COVID-19

The pathological processes by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection that make the virus a major threat to global health are insufficiently understood. Inefficient viral clearance at any stage is a hallmark of coronavirus disease 2019 (COVID-19). Disease severity is associated with increases in peripheral blood cytokines among which interleukin 10 (IL-10) increases particularly early and independent of patient age, which is not seen in active SARS-CoV infection. Here, we consider the known multi-faceted immune regulatory role of IL-10, both in protecting the lung from injury and in defense against infections, as well as its potential cellular source. While the absence of an IL-10 response in SARS is thought to contribute to early deterioration, we suspect IL-10 to protect the lung from early immune-mediated damage and to interfere with viral clearance in COVID-19. This may further both viral spread and poor outcome in many high-risk patients. Identifying the features of the viral genotype, which specifically underlie the different IL-10 dynamics as an etiological endotype and the different viral load kinetics and outcomes as clinical phenotype, may unveil a new immune evasive strategy of SARS-CoV-2.

Harnessing Recent Advances in Synthetic DNA and Electroporation Technologies for Rapid Vaccine Development Against COVID-19 and Other Emerging Infectious Diseases

DNA vaccines are considered as a third-generation vaccination approach in which antigenic materials are encoded as DNA plasmids for direct in vivo production to elicit adaptive immunity. As compared to other platforms, DNA vaccination is considered to have a strong safety profile, as DNA plasmids neither replicate nor elicit vector-directed immune responses in hosts. While earlier work found the immune responses induced by DNA vaccines to be sub-optimal in larger mammals and humans, recent developments in key synthetic DNA and electroporation delivery technologies have now allowed DNA vaccines to elicit significantly more potent and consistent responses in several clinical studies. This paper will review findings from the recent clinical and preclinical studies on DNA vaccines targeting emerging infectious diseases (EID) including COVID-19 caused by the SARS-CoV-2 virus, and the technological advancements pivotal to the improved responses-including the use of the advanced delivery technology, DNA-encoded cytokine/mucosal adjuvants, and innovative concepts in immunogen design. With continuous advancement over the past three decades, the DNA approach is now poised to develop vaccines against COVID-19, as well as other EIDs.