ABSTRACT
SARS-CoV-2 is a positive-sense RNA virus that contains open reading frame 1ab (ORF1ab) to produce 16 nonstructural proteins (nsps). Five stem-loops (SL) are found in the 5' UTR of the RNA that are involved in myriad viral functions and are labeled SL1 through SL5. SL1 is crucial to viral replication. Upon viral infection, nsp1 binds the ribosomal 40S subunit to inhibit all host mRNA translation. Upon SL1 binding to nsp1, viral mRNA can be processed by the ribosome, allowing viral proteins to be produced. In this study, we are examining small DNA oligonucleotides that bind to SL1-mimetic DNA in order to block SL1-nsp1 interactions. We designed a DNA analog of the SL1 hairpin and two small DNA oligonucleotides that are complementary to either the helical stem or the loop region of SL1. The binding of these oligonucleotides to the SL1 hairpin should allow the formation of either an alternate duplex or a triplex structure. Isothermal titration calorimetry (ITC) and circular dichroism (CD) techniques were performed in 1 MKCl and 10 mM MgCl2 at two different pH (5.5 and 7.0) to examine structural and thermodynamics of binding. ITC of the two oligonucleotides showed modest binding. Results from DNA binding experiments, thermal denaturation, and CD show the hairpin structure is thermodynamically more favored and mostly remains intact under the conditions examined.Copyright © 2023 The American Society for Biochemistry and Molecular Biology, Inc.
ABSTRACT
Coronavirus disease 19 (COVID-19) is a highly contagious and lethal disease caused by the SARS-CoV-2 positive-strand RNA virus. Nonstructural protein 13 (Nsp13) is the highly conserved ATPase/helicase required for replication of the SARS-CoV-2 genome which allows for the infection and transmission of COVID-19. We biochemically characterized the purified recombinant SARS-CoV-2 Nsp13 helicase protein expressed using a eukaryotic cell-based system and characterized its catalytic functions, focusing on optimization of its reaction conditions and assessment of functional cooperativity among Nsp13 molecules during unwinding of duplex RNA substrates. These studies allowed us to carefully determine the optimal reaction conditions for binding and unwinding various nucleic acid substrates. Previously, ATP concentration was suggested to be an important factor for optimal helicase activity by recombinant SARS-CoV-1 Nsp13. Apart from a single study conducted using fixed concentrations of ATP, the importance of the essential divalent cation for Nsp13 helicase activity had not been examined. Given the importance of the divalent metal ion cofactor for ATP hydrolysis and helicase activity, we assessed if the molar ratio of ATP to Mg2+ was important for optimal SARS-CoV-2 Nsp13 RNA helicase activity. We determined that Nsp13 RNA helicase activity was dependent on ATP and Mg2+ concentrations with an optimum of 1 mM Mg2+ and 2 mM ATP. Next, we examined Nsp13 helicase activity as a function of equimolar ATP:Mg2+ ratio and determined that helicase activity decreased as the equimolar concentration increased, especially above 5 mM. We determined that Nsp13 catalytic functions are sensitive to Mg2+ concentration suggesting a regulatory mechanism for ATP hydrolysis, duplex unwinding, and protein remodeling, processes that are implicated in SARS-CoV-2 replication and proofreading to ensure RNA synthesis fidelity. Evidence is presented that excess Mg2+ impairs Nsp13 helicase activity by dual mechanisms involving both allostery and ionic strength. In addition, using single-turnover reaction conditions, Nsp13 unwound partial duplex RNA substrates of increasing doublestranded regions (16-30 base pairs) with similar kinetic efficiency, suggesting the enzyme unwinds processively in this range under optimal reaction conditions. Furthermore, we determined that Nsp13 displayed sigmoidal behavior for helicase activity as a function of enzyme concentration, suggesting that functional cooperativity and oligomerization are important for optimal activity. The observed functional cooperativity of Nsp13 protomers suggests the essential coronavirus RNA helicase has roles in RNA processing events beyond its currently understood involvement in the SARS-CoV-2 replication-transcription complex (RTC), in which it was suggested that only one of the two Nsp13 subunits has a catalytic function, whereas the other has only a structural role in complex stability. Altogether, the intimate regulation of Nsp13 RNA helicase by divalent cation and protein oligomerization suggests drug targets for modulation of enzymatic activity that may prove useful for the development of novel anti-coronavirus therapeutic strategies. This work was supported by the Intramural Training Program, National Institute on Aging (NIA), NIH, and a Special COVID-19 Grant from the Office of the Scientific Director, NIA, NIH.Copyright © 2023 The American Society for Biochemistry and Molecular Biology, Inc.
ABSTRACT
The genomic material of SARS-CoV-2 is a positive-sense single-stranded RNA. SARS-CoV-2 produces non-structural protein 1 (NSP1), which inhibits host cell translation by binding its' N-terminal to the host's 40S ribosomal subunit. Once NSP1 is bound its C-terminal domain folds and binds to the mRNA entry channel. Stem loop 1 (SL1) in the 5'-UTR of the viral mRNA binds to NSP1 to abrogate translation inhibition leading to the expression of viral proteins. SL1 contains a 1 x 2 internal loop that is not seen in other coronaviruses and may be involved in conformational changes that influence SL1-NSP1 interactions. The 1 x 2 internal loop of SL1 contains a putative A*C non-canonical base pair. The U6 snRNA also contains a 1 x 2 internal loop known to undergo conformation changes in response to pH and magnesium ion binding. Here we examine the thermodynamic properties and magnesium binding of the 1 x 2 internal loop of SL1 in varying helical contexts. Thermal denaturation experiments were performed on various DNA and RNA constructs in the presence of 1 M KCl or 10 mM magnesium chloride at a pH of 5.5 and 7. We show that formation of the A+*C base pair and the construct stability in the presence of magnesium ions is dependent on the helical context.Copyright © 2023 The American Society for Biochemistry and Molecular Biology, Inc.
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Plasmid-mediated quinolone resistance (PMQR) genes confer low resistance to Fluoroquinolones (FQs). This study aims to detect five PMQR genes among FQs-resistant Klebsiella pneumoniae isolated from various clinical specimens. Out of 120 K. pneumoniae isolates, 68 FQs-resistance K. pneumoniae were included in a molecular study. Standard microbiological tests were used for identification and antimicrobial susceptibility. For the detection of PMQR genes, conventional polymerase chain reaction was used. A molecular study revealed that (73.5%) of samples harbored PMQR genes, and among them, 58% were co-carriages of PMQR gene variants. Aac (6')-Ib-cr gene was predominant (47.1%) among samples, and qepA had the lowest percentage (11.8%), qnr genes were (32.4%) (29.4%) (20.6%) qnrS, qnrB, and qnrA respectively. Overall, high percentages of PMQR genes were detected, and almost all of samples were phenotypically resistant to ciprofloxacin. As well, there was a significant statistical relationship between phenotypically ESBL-producers and qnrB and qepA genes.Copyright © Abdulkareem MM et al. This is an open access article distributed under the terms of the Creative Commons Attribution License (CC-BY 4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.
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Background: Coronavirus disease (COVID-19) has now morphed into the most serious healthcare challenge that the world has faced in a century. The coronavirus disease (COVID-19) was declared as a public health emergency of international concern (PHEIC) on January 30, 2020, and a pandemic on March 11 by the World Health Organization (WHO). The number of cases and the death toll are rapidly increasing frequently because of its fast transmission from human to human through droplets, contaminated hands or body, and inanimate surfaces. Objective(s): SDS has been found to exhibit broad-spectrum and effective microbicidal and viral inactivation agents through the denaturation of both envelope and non-envelop proteins Methods: Viable SARS-COV-2 particles may also be found on contaminated sites such as steel surfaces, plastic surfaces, stainless steel, cardboard, and glass surfaces that can serve as a source of virus transmission. We reviewed the available literature about the SARS-CoV-2 persistence on inanimate surfaces as well as the decontamination strategies of corona and other viruses by using Sodium dodecyl sulfate (SDS) as well as other cleaning chemicals and disinfectants. Result(s): The efficacy of SDS has been amply demonstrated in several studies involving human immunodeficiency virus (HIV), human papillomavirus (HPV) and herpes simplex virus (HSV). SDS has also been found as deactivator of SARS-CoV-2. In toxic profile, up to 1% concentration of SDS is safe for humans and showed no toxic effect if ingested. Conclusion(s): Since no specific treatment is available as yet so containment and prevention continue to be important strategies against COVID-19. In this context, SDS can be an effective chemical disinfectant to slow and stop the further transmissions and spread of COVID-19.Copyright © 2021 Bentham Science Publishers.
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One of the main antigen that can be used for serological testing is the nucleocapsid (N) which is the most abundant viral-derived protein in SARS-CoV-2 where this virus can cause COVID19 disease. The aim of this study was to develop the SARS-CoV-2 N recombinant protein using Escherichia coli expression system. A total of 1,089 nucleotides encoding 362 amino acids of SARS-CoV-2 N was cloned to pET-14b vector. The plasmid then expressed in E. coli BL21 (DE3) and induced with 1.0 mM IPTG (Isopropyl-β-d-1-thiogalactopyranoside). The cell was harvested using denaturation lysis buffer due to inclusion body formation of SARS-CoV-2 N protein. Dialysis processed and concentrated using PEG-6000 resulted 0.992 mg/ml protein yield. Analysis of SARS-CoV-2 N recombinant protein using SDS-PAGE technique showed approximately 37.0 kDa specific band target protein. Application of this SARS-CoV-2 N recombinant protein to vaccinated and non-vaccinated antibody serum samples using ELISA technique indicated the significant result of optical density mean at 0.603 and 0.135, respectively. This study revealed that the production of SARS-COV-2 N recombinant protein could be carried out in E. coli expression system under denatured conditions, therefore the methods are more effective in producing the protein as a basic material in immuno-diagnostic assay. © 2023, Bogor Agricultural University. All rights reserved.
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Objectives: Gastrointestinal endoscopy (GIE) is useful for the early detection and treatment of many diseases;however, GIE is considered a high-risk procedure in the coronavirus disease 2019 (COVID-19) pandemic era. This study aimed to explore the rate of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) positivity in saliva and gastrointestinal fluids to which endoscopy medical staff are exposed. Method(s): The study was a single-center cross-sectional study. From June 1 to July 31, 2020, all patients who underwent GIE at Yokohama City University Hospital were registered. All patients provided 3 mL of saliva. For upper GIE, 10 mL of gastric fluid was collected through the endoscope. For lower GIE, 10 mL of intestinal fluid was collected through the endoscope. The primary outcome was the positive rate of SARS-CoV-2 in saliva and gastrointestinal fluids. We also analyzed serum-specific antibodies for SARS-CoV-2 and patients' background information. Result(s): A total of 783 samples (560 upper GIE and 223 lower GIE samples) were analyzed. Polymerase chain reaction (PCR) on saliva samples did not show any positive results in either upper or lower GIE samples. However, 2.0% (16/783) of gastrointestinal fluid samples tested positive for SARS-CoV-2. No significant differences in age, sex, purpose of endoscopy, medication, or rate of antibody test positivity were found between PCR positive and PCR negative cases. Conclusion(s): Asymptomatic patients, even those with no detectable virus in their saliva, had SARS-CoV-2 in their gastrointestinal tract. Endoscopy medical staff should be aware of infection when performing procedures. The study was registered as UMIN000040587. Text S1 Detection of SARS-Co-V-2 genomic RNA and serological tests for SARS-CoV-2 antibodies. Detection of SARS-CoV-2 genomic RNA was performed according to the Manual for the Detection of Pathogen 2019-nCoV Ver.2.61) provided by the National Institute of Infectious Diseases in Japan. RNA extraction was performed from a 140-microl sample using a QIAamp Viral RNA Mini Kit (Qiagen, Valencia, CA, USA) according to the manufacturer's protocol. The final elution was performed with 60 microl of elution buffer, and 5 microl of extracted RNA was subject to evaluation by real-time quantitative PCR (RT-qPCR). The RT-qPCR reaction mix was prepared using TaqMan Fast Virus 1-Step Master Mix (Thermo Fisher Scientific, Foster City, CA, USA) and primer/probe N2 (2019-nCoV) (TakaRa, Tokyo, Japan) according to the manufacturer's protocol. Primer sequences are shown in Supplementary Table 1. RT-PCR was conducted by StepOnePlusTM Real-Time PCR System (Applied Biosystems, Thermo Fisher Scientific, MA. USA) The denaturation and annealing/extension steps were repeated for 45 cycles. A well containing absolutely quantified artificial synthetic template RNA was evaluated as a positive control, and a well without template RNA was evaluated as a negative control. According to the Manual for the Detection of Pathogen 2019-nCoV Ver.2.6, the assay was considered valid when the following criteria were met: (a) 50 copies/well of template RNA successfully detected before 40 cycles and (b) nonspecific amplification not detected in the well lacking template RNA up to 45 cycles. Samples showing amplification of SARS-CoV-2 genomic RNA before 40 cycles were defined as positive for COVID-19. We previously reported a method for serological testing2),3). Briefly, an enzyme-linked immunosorbent assay was performed to detect and quantify anti-SARS-CoV-2 antibodies in plasma. We used an N-terminally-truncated nucleocapsid protein (NP) and the receptor-binding domain of the spike protein (SP) as antigens (100 ng/well). Following blocking with phosphate-buffered saline (PBS) containing 3 % skimmed milk for 2 h, 100 microl of diluted plasma (1:100) were added and incubated for 1 h. After three washes with PBS-T, wells were incubated with 100 microl of diluted horseradish peroxidase-conjugated goat anti-human immunoglobulin G antibody (1:20000) for 1 h. Afte five additional washes with PBS-T, 100 microl of Tetramethylbenzidine Substrate (Kirkegaard & Perry Laboratories, Maryland, USA) was added and incubated for 10 mins. The reaction was terminated by adding 50 microl of 2-M H2SO4, and optical density was measured at 450 nm using a plate reader. In the serological test, COVID-19 antibody positivity was defined as a value greater than 1.139 in the NP test and greater than 0.277 in the SP test. In this study, a positive result in either the NP test or the SP test was defined as a positive antibody test. Copyright © 2022 Japan Gastroenterological Endoscopy Society. All rights reserved.
ABSTRACT
The recent pneumonia spread brought about by a novel corona virus (COVID-19) in china is representing an incredible risk and proclaimed a worldwide emergency of public health. It has spread to the world and infected people with COVID-19 disease. In addition to the absence of explicit treatment as well as vaccine, COVID-19 are currently known to reveal a noteworthy environmental resistance. The transmission of virus was found to be spread through human -to -human that make it easily diffused. The transmission comes from the droplets of infected when sneezing or coughing. These droplets can survive on the inanimate surface even in air and transmitted the virus to human. The aim of our project is to design and develop an antiseptic disinfection spraying system has ability to disinfect large scale area with less time consuming and minimal human interactions. The range of drone is 100m and speed 8m/s then flight time is 15 min. It additionally proposes detail of the range of antiseptic -disinfectant and denaturation that have been used in this operation. The term contactless has been strongly used post COVID keeping that in mind we develop a model which will carry the disinfectant spraying tank with drone for spraying which will be controlled through an android application. The advantage of the UAV can be fly at any altitude, offer high quality data's, by using sensors, algorithm. © 2022 International Journal of Health Sciences.All rights reserved.
ABSTRACT
The SARS-CoV-2 virus caused the COVID-19 pandemic is related to the SARS-CoV-1 and MERS coronaviruses, which were resulted in 2003 and 2012 epidemics. Antibodies in patients with COVID-19 emerge 7–14 days after the onset of symptoms and gradually increase. Because the COVID-19 pandemic is still in progress, it is hard to say how long the immunological memory to the SARS-CoV-2 virus may be retained. The aim of this study was to study a ratio between humoral and cellular immunity against the SARS-CoV-2 S protein in COVID-19 convalescents. There were enrolled 60 adults with mild to moderate COVID-19 2 to 12 months prior to the examination. The control group consisted of 15 adults without COVID-19 or unvaccinated. Specific antibodies to the SARS-CoV-2 virus were determined by ELISA with the SARS-CoV-2-IgG-ELISA-BEST kit. To determine the specific IgG and IgA subclasses, the anti-IgG conjugate from the kit was replaced with a conjugate against the IgG subclasses and IgA. Additional incubation with or without denaturing urea solution was used to determine the avidity of antibodies. Peripheral blood mononuclear cells were isolated by gradient centrifugation, incubated with or without coronavirus S antigen for 20 hours, stained by fluorescently labeled antibodies, and the percentage of CD8highCD107a cells was assessed on flow cytometer BD FACSCanto II. In the control group, neither humoral nor cellular immunity against the SARS-CoV-2 S protein was found. In the group of convalescents, the level of IgG antibodies against the SARS-CoV-2 S protein varies greatly not being strictly associated with the disease duration, with 57% and 43% of COVID-19 patients having high vs. low level of humoral response, respectively. A correlation between level of specific IgG and IgA was r = 0.43. The avidity of antibodies increased over time in convalescents comprising 49.9% at 6–12 months afterwards. No virus-specific IgG2 and IgG4 subclasses were detected, and the percentage of IgG1 increased over time comprising 100% 6–12 months after recovery. 50% of the subjects examined had high cellular immunity, no correlations with the level of humoral immunity were found. We identified 4 combinations of humoral and cellular immunity against the SARS-CoV-2 S protein: high humoral and cellular, low humoral and cellular, high humoral and low cellular, and vice versa, low humoral and high cellular immunity.
ABSTRACT
Hand hygiene is crucial as it gets contaminated easily from direct contact with airborne microorganism droplets and droplet nuclei from coughs and sneezes. In situations like a pandemic outbreak of COVID-19, it is imperative to interrupt the transmission chain of the pathogens by the practice of proper hand sanitization. It can be achieved with contact isolation and strict infection control tools like maintaining good hand hygiene in the house, in hospital settings, and in public. The success of hand sanitization solely depends on practical hand disinfecting agents formulated in various types and forms, such as antimicrobial soaps and water-based or alcohol-based hand sanitiser, with the latter being widely used in hospital settings and by common people. Most effective hand sanitiser products are alcohol-based formulations containing 62%–95% of alcohol as they can denature the proteins of microbes and the ability to inactivate pathogens. Considering the need, we prepared five herbal hand sanitizers in Arka form using drugs of krimighna gana dravyas that have an antimicrobial property and are volatile. Among all the five preparations, it was noticed from the statistical analysis, that there was a significant reduction in the bacterial count in the ‘immediate application’ of Batch I (Tulsi Arka), and Batch II (Tulsi, Nimba Arka) showed a significant decrease in the bacterial count in ‘after 30 minutes of application’. However, Batch III (Tulsi, Nimba, Haridra arka) gave an intermediate result in ‘immediate application’ and ‘after 30 minutes of application’. None of the preparations showed any sort of irritation, dryness or discomfort to the subjects even after 30 minutes while conducting the study.
ABSTRACT
Background-aim: World Health Organization (WHO) announced that diagnostic testing for Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-COV2) should be performed by real-time reverse transcriptase-polymerase chain reaction (RT-PCR). Most of these methods use different gene props and therefore the sensitivity and specificity of each method may different. In this study, we have compared two RT-PCR methods using two different genes for detection SARS-COV2. Methods: A total of random 40 nasopharyngeal swab samples were collected, transported and received in iced box shipment. All samples were performed on two separate semi-automated PCR systems (Qiagen and Abbott m2000). For Qiagen method, 200uL from each sample were added in 96-well QiAcube plate which loaded in QiAcube HT (SN:019658;Qiagen, Germany) to extract RNA. Following extraction, master mix prepared using SARS-COV2-RT-PCR kit 1.0 (REF: 821005;Altona, Germany) for 44 samples including 40 patient samples, two negative controls using nuclease-free water (with and without internal control), and two positive controls (with and without internal control). Extraction elute of each sample (20uL) added to master mix (10uL) to have a total volume of 30uL which uploaded into Rotor-Gene Q (SN:R0219307;Qiagen, Germany). The primer pair used to amplify S gene and E gene in SARS-COV2. Amplifications were done as follow: reverse transcriptase (20 minutes at 55oC);initial denaturation (2 minutes at 95oC);45 cycles of denaturation (15 seconds at 95oC), annealing for (45 seconds at 55oC), and extension (15 seconds at 72oC). Results reported as valid for internal control less than 35 cycle threshold (CT). The Abbott m2000 System uses SARS-CoV-2 assay was a dual target assay for the RdRp and N genes. All 40 samples were extracted using m2000sp (Abbott, United States) as recommend by manufacture using 100uL. An RNA sequence that was unrelated to the SARS-CoV-2 target sequence was introduced into each specimen at the beginning of sample preparation. This unrelated RNA sequence was simultaneously amplified by RT-PCR and serves as an internal control (IC) to demonstrate that the process has proceeded correctly for each sample. Following extraction, master mix (20uL) added to extraction elute of each sample (30uL) to have a total volume of 50uL which uploaded into m2000rp (Abbott, United States). Amplification were done as follow: reverse transcriptase (25 minutes at 55oC);initial denaturation (5 minutes at 94oC);40 cycles of denaturation (20 seconds at 94oC), annealing for (55 seconds at 55oC), and extension (15 seconds at 72oC). Result: All samples had valid extraction process with a CT value of internal control between 26.97 to 28.89. A total of 30 samples displayed positive results and 10 samples exhibited negative results with 100% agreement for both methods. This has resulted with a 100% accuracy between both methods. Conclusions: Both semi-automated methods from Qiagen and Abbott are comparable and accurate despite different technology and different primer genes.
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Herein we report the obtaining of 1-(3,4-dihydroquinolin-1(2H)-yl)-2- (4-isobutylphenyl)propan-1-one and its characterization. The newly obtained hybrid and its derivatives (hybrids of ibuprofen with 1,2,3,4-tetrahydroisoquinoline, and piperidine) were screened for their in vitro antioxidant, antitryptic, and inhibition of albumin denaturation activity. The lipophilicity was established using both reversed-phase thin layer chromatography and in silico calculations.
ABSTRACT
Since SARS-COV-2 virus spread worldwide and COVID-19 turned rapidly into a pandemic illness, the necessity for vaccines and diagnostic tests became crucial. The viral surface is decorated with Spike, the major antigenic determinant and main target for vaccine development. Within Spike, the receptor binding domain (RBD), constitutes the main target of highly neutralizing antibodies found in COVID-19 convalescent plasma. Besides vaccination, another important aspect of Spike (and RBD) is their use as immunogen for the development of poli- and monoclonal antibodies (mAbs) for therapeutic and diagnostic purposes. Here we report the development and preliminary biochemical characterization of a set of monoclonal antibodies against the Spike RBD domain along with the recombinant expression of two mayor COVID-19 protein reagents: the viral Spike RBD domain and the extracellular domain of the human receptor ACE2. RBD and the extracellular domain of ACE2 (aa 1-740) were obtained through transient gene transfection (TGE) in two different mammalian cell culture systems: HEK293T adherent monolayers and Expi293F™ suspension cultures. Due to its low cost and ease scale-up, all transfections were carried with polyethyleneimine (PEI). Expressed proteins were purified from culture supernatants by immobilized metal affinity chromatography. Anti-RBD mAbs were developed from two different immunization schemes: one aimed to elicit antibodies with viral neutralizing potential, and the other with the ability to recognize denatured RBD for routine lab immunoassays. To achieve this, the first group of mice was immunized with RBD in aluminum salts (RBD/Al) and the other with RBD emulsified in Freunds adjuvant (RBD/FA). Polyclonal and monoclonal antibody reactivities against native or denatured RBD forms were then assessed by ELISA. Complete RBD denaturation was followed by intrinsic fluorescence spectral changes upon different physicochemical stress treatments. As expected, RBD/Al immunized mice developed an antibody response shifted to native RBD while those immunized with RBD/FA showed a high response against both forms of the protein. In accordance with the observed polyclonal response, RBD/FA derived mAbs recognize both, native and denatured RBD. On the contrary, hybridomas generated from the RBD/Al protocol mostly recognize RBD in its native state. Further ELISA binding assays revealed that all RBD/FA derived mAbs can form a trimeric complex with ACE2 and RBD, denoting they would not have viral neutralizing activity. ELISA competition assays with the RBD/ACE2 complex aimed to determine the neutralization potential of the RBD/Al derived mAbs are under way. Overall, the anti-Spike RBD mAbs and the recombinant RBD and ACE2 proteins presented here constitute valuable tools for diverse COVID-19 academic research projects and local immunity surveillance testing.
ABSTRACT
In the present work the temperature response of the constitutive S1 segment of the SARS-CoV-2 Spike Glycoprotein (GPS) has been studied. The intensity of the Raman bands remained almost constant before reaching a temperature of 133 °C. At this temperature a significant reduction of peak intensities was observed. Above 144 °C the spectra ceased to show any recognizable feature as that of the GPS S1, indicating that it had transformed after the denaturation process that it was subjected. The GPS S1 change is irreversible. Hence, Raman Spectroscopy (RS) provides a precision method to determine the denaturation temperature (TD) of dry powder GPS S1. The ability of RS was calibrated through the reproduction of TD of other well studied proteins as well as those of the decomposition temperature of some amino acids (AA). Through this study we established a TD of 139 ± 3 °C for powder GPS S1 of SARS-CoV-2.
Subject(s)
COVID-19 , Spike Glycoprotein, Coronavirus , Humans , SARS-CoV-2 , Spectrum Analysis, Raman , TemperatureABSTRACT
The disinfecting properties of sun (heat and UV radiation) are adequate in warm sunny regions to rid beach sand of coronavirus particles, if present. Here we detail the mechanism of natural disinfection offered by the sun on coronaviral particles that may find their way onto beach sand. We conclude that heat and UV radiation generated by the sun destroy the virus infection ability.