scholarly journals Personal care formulations demonstrate virucidal efficacy against multiple SARS-CoV-2 variants of concern: implications for hand hygiene

2021 ◽  
Author(s):  
Sayandip Mukherjee ◽  
Carol K. Vincent ◽  
Harshinie W. Jayasekera ◽  
Ashish Shrikant Yekhe
Keyword(s):  
Hand Hygiene ◽  
Parent Strain ◽  
High Viral Load ◽  
Viral Envelope ◽  
Original Strain ◽  
Personal Care ◽  
Nucleocapsid Proteins ◽  
Proven Efficacy ◽  
Roll Out

AbstractThe second and third waves of COVID-19 pandemic have largely been driven by the surge of successive SARS-CoV-2 variants of concern (VOC). These VOC have rapidly spread through multiple geographies being enabled by high transmission rates and/or high viral load compared to the original parent strain. Consequently, the altered phenotypes of these VOC have posed greater challenges to diagnostic and clinical management of COVID-19. Despite considerable progress being made on vaccine roll out, practicing proper hand hygiene has been advocated as a consistent precautionary intervention as more virulent VOC continue to emerge and spread across geographies.Two variants of concern, namely beta and delta, have recently been shown to escape antibody-mediated neutralization by virtue of acquired mutations in the receptor-binding domain of the viral spike protein which binds to the human ACE2 receptor for cellular entry. In this report we have empirically determined the efficacy of a range of personal care formulations in inactivating the beta and delta variants of SARS-CoV-2. High titres of these variants were exposed to marketed personal care formulations from Unilever under standard in-vitro suspension test-based conditions relevant to end-user habits. All the formulations demonstrated greater than 99.9% reduction in viral infective titres. The rate of inactivation by these products were comparable to that of the original strain of SARS-CoV-2 virus tested under the same conditions. Therefore, it can be concluded that well-designed personal care formulations when tested under consumer-centric conditions, and with proven efficacy against the parent strain of SARS-CoV-2 will continue to be effective against extant and emerging variants of SARS-CoV-2. This is through their broad-spectrum mode of action (disruption of lipid bilayer of the host-derived viral envelope, denaturation of envelop and nucleocapsid proteins, and disruption of genome) which is independent of the escape mutations that facilitate immune evasion or enhanced transmissibility.

scholarly journals Comparative studies on Salmonella typhi grown in vivo and in vitro III. The immunizing potencies of acetone-killed vaccines prepared from in vivo and in vitro grown bacteria and the immunizing potency of substances isolated from infected organs

1963 ◽  
Vol 61 (3) ◽  
pp. 353-363 ◽  
Author(s):  
A. L. Olitzki ◽  
Dina Godinger
Keyword(s):  
Comparative Studies ◽  
Guinea Pigs ◽  
Peritoneal Fluid ◽  
Parent Strain ◽  
Salmonella Typhi ◽  
Challenge Strain

1. Salmonella typhi, strain Ty2, grown in vivo and employed as acetone-dried vaccine possessed a higher immunizing potency than the descendants of the same parent strain grown in vitro and employed as vaccine.2. When 2 × 108in vitro-grown bacteria were employed as challenge, the immunizing effects of both types of vaccine were more marked than after administration of 2 × 108in vivo-grown bacteria as challenge.3. The higher potency of the in vivo-grown vaccine was apparent in all experiments, whether the challenge strain was grown in vivo or in vitro.4. Immunogenic substances were isolated from infected organs of mice and guinea-pigs, and an immunogenic substance from the peritoneal fluid of the infected guinea-pigs was concentrated by precipitation with ethanol.

scholarly journals Development of Resistance in Wild-Type and Hypermutable Pseudomonas aeruginosa Strains Exposed to Clinical Pharmacokinetic Profiles of Meropenem and Ceftazidime Simulated In Vitro

2007 ◽  
Vol 51 (10) ◽  
pp. 3642-3649 ◽  
Author(s):  
Beate Henrichfreise ◽  
Irith Wiegand ◽  
Ingeborg Luhmer-Becker ◽  
Bernd Wiedemann
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Parent Strain ◽  
Resistance Mechanisms ◽  
In Vitro Models ◽  
Wild Type ◽  
Resistance Development ◽  
Development Of Resistance ◽  
Pharmacokinetic Profiles ◽  
Mutant Prevention Concentration

ABSTRACT In this study we investigated the interplay of antibiotic pharmacokinetic profiles and the development of mutation-mediated resistance in wild-type and hypermutable Pseudomonas aeruginosa strains. We used in vitro models simulating profiles of the commonly used therapeutic drugs meropenem and ceftazidime, two agents with high levels of antipseudomonal activity said to have different potentials for stimulating resistance development. During ceftazidime treatment of the wild-type strain (PAO1), fully resistant mutants overproducing AmpC were selected rapidly and they completely replaced wild-type cells in the population. During treatment with meropenem, mutants of PAO1 were not selected as rapidly and showed only intermediate resistance due to the loss of OprD. These mutants also replaced the parent strain in the population. During the treatment of the mutator P. aeruginosa strain with meropenem, the slowly selected mutants did not accumulate several resistance mechanisms but only lost OprD and did not completely replace the parent strain in the population. Our results indicate that the commonly used dosing regimens for meropenem and ceftazidime cannot avoid the selection of mutants of wild-type and hypermutable P. aeruginosa strains. For the treatment outcome, including the prevention of resistance development, it would be beneficial for the antibiotic concentration to remain above the mutant prevention concentration for a longer period of time than it does in present regimens.

VACCINE HESITANCY TO VACCINE DESPERATION! EXPERIENCES FROM 2 VACCINATION CENTERS IN MUMBAI.

2021 ◽  
pp. 43-45
Author(s):  
Reena J. Wani ◽  
Sanjay Panchal ◽  
Kinjal Chauhan ◽  
Varun J. Wani ◽  
Priya H. Manihar ◽  
...  
Keyword(s):  
Side Effects ◽  
Adverse Events ◽  
Hand Hygiene ◽  
Special Reference ◽  
Vaccine Hesitancy ◽  
Long Term Effects ◽  
Social Distancing ◽  
Roll Out ◽  
Available Resources

Since the beginning of the COVID-19 Pandemic and Lockdown on March 2020 till date, measures like hand hygiene, social distancing and testing have worked only partially to contain the cases and deaths. Cooper and Nair Hospitals were amongst the nodal centres identied in January 2021 to launch the Nationwide Vaccination drive in Mumbai. Aim: To highlight the pattern of vaccination roll-out, procedures in various phases and discuss concerns, challenges and effect on our workforce and workplan. Methodology: We reviewed the patterns, uptake of vaccine, procedures and problems faced by our vaccination centres from January 15 till April 30 (4 months). We also looked into adverse events following immunization (AEFI) reported. th th Results: Over 68,000 vaccine doses have been administrated in Cooper alone by April end, and issues were analysed in detail with special reference to logistics & challenges. AEFI were very few. We found that initially anxiety about side effects, concerns about choice of vaccine and long-term effects were the major impediments to vaccination. Later on, the demand exceeded the supply. Conclusion: Although vaccination is not the nal answer, it is an important tool to improve our response to the pandemic. Reviewing, restructuring available resources is essential in pandemic situations. Proper planning, counselling and choice in the way forward in this crisis.

Aerobic resistance of Trichomonas vaginalis to metronidazole induced in vitro

Parasitology ◽  
1993 ◽  
Vol 106 (1) ◽  
pp. 31-37 ◽  
Author(s):  
J. Tachezy ◽  
J. Kulda ◽  
E. Tomková
Keyword(s):  
Parent Strain ◽  
Trichomonas Vaginalis ◽  
Drug Resistant ◽  
Ferredoxin Oxidoreductase ◽  
Low Concentrations ◽  
Percent Concentration ◽  
Resistant Strains ◽  
Pyruvate Ferredoxin Oxidoreductase

SUMMARYAerobic resistance of Trichomonas vaginalis to metronidazole was induced in vitro by anaerobic cultivation of drug-susceptible trichomonads with low concentrations of the drug (2–3 μg/ml) for 50 days. Minimal lethal concentrations (MLC) for metronidazole of the resistant derivatives were high in aerobic susceptibility assays (MLC = 216–261.5 μg/ml) but low in anaerobic assays (MLC = 4.2–6.3 μg/ml), surpassing MLC values of their parent strain approximately 50-fold and 3-fold under aerobiosis and anaerobiosis, respectively. Sensitivity to metronidazole under anaerobic conditions and activity of the hydrogenosomal enzyme pyruvate: ferredoxin oxidoreductase indicated that the resistance was of the aerobic type. Dependence of the resistance manifestation on O2 was further confirmed by susceptibility assays in vitro performed in defined gas mixtures of different oxygen content (1–20%). Five percent concentration of O2 proved to be the threshold required for resistance demonstration and the MLC values further increased with increasing O2 concentrations. The in vitro-induced resistance was also demonstrated in vivo by subcutaneous mouse assay. The dose of metronidazole needed to cure 50% of infected mice (DC50) was 223 mg/kg × 3 for resistant derivative MR-3a but 6.6 mg/kg × 3 only for its drug-susceptible parent strain. The metronidazole – resistant strains developed in this study correspond by their properties to drug-resistant T. vaginalis strains isolated from patients refractory to treatment, and promise to be a useful tool in the study of 5-nitroimidazole aerobic resistance.

scholarly journals The YXXL Sequences of a Transmembrane Protein of Bovine Leukemia Virus Are Required for Viral Entry and Incorporation of Viral Envelope Protein into Virions

1999 ◽  
Vol 73 (2) ◽  
pp. 1293-1301 ◽  
Author(s):  
Kazunori Inabe ◽  
Masako Nishizawa ◽  
Shigeru Tajima ◽  
Kazuyoshi Ikuta ◽  
Yoko Aida
Keyword(s):  
Viral Entry ◽  
Envelope Protein ◽  
Bovine Leukemia Virus ◽  
Leukemia Virus ◽  
Transient Transfection ◽  
Viral Envelope ◽  
Tyrosine Residue ◽  
Wild Type ◽  
Viral Envelope Protein

ABSTRACT The cytoplasmic domain of an envelope transmembrane glycoprotein (gp30) of bovine leukemia virus (BLV) has two overlapping copies of the (YXXL)2 motif. The N-terminal motif has been implicated in in vitro signal transduction pathways from the external to the intracellular compartment and is also involved in infection and maintenance of high viral loads in sheep that have been experimentally infected with BLV. To determine the role of YXXL sequences in the replication of BLV in vitro, we changed the tyrosine or leucine residues of the N-terminal motif in an infectious molecular clone of BLV, pBLV-IF, to alanine to produce mutated proviruses designated Y487A, L490A, Y498A, L501A, and Y487/498A. Transient transfection of African green monkey kidney COS-1 cells with proviral DNAs that encoded wild-type and mutant sequences revealed that all of the mutated proviral DNAs synthesized mature envelope proteins and released virus particles into the growth medium. However, serial passages of fetal lamb kidney (FLK) cells, which are sensitive to infection with BLV, after transient transfection revealed that mutation of a second tyrosine residue in the N-terminal motif completely prevented the propagation of the virus. Similarly, Y498A and Y487/498A mutant BLV that was produced by the stably transfected COS-1 cells exhibited significantly reduced levels of cell-free virion-mediated transmission. Analysis of the protein compositions of mutant viruses demonstrated that lower levels of envelope protein were incorporated by two of the mutant virions than by wild-type and other mutant virions. Furthermore, a mutation of a second tyrosine residue decreased the specific binding of BLV particles to FLK cells and the capacity for viral penetration. Our data indicate that the YXXL sequences play critical roles in both viral entry and the incorporation of viral envelope protein into the virion during the life cycle of BLV.

scholarly journals In vitro activity of human recombinant alpha-2b interferon against SARS-CoV-2 virus

2021 ◽  
Vol 66 (2) ◽  
pp. 123-128
Author(s):  
S. Ya. Loginova ◽  
V. N. Shсhukina ◽  
S. V. Savenko ◽  
S. V. Borisevich
Keyword(s):  
Cell Culture ◽  
Antiviral Activity ◽  
Viral Infections ◽  
Complete Suppression ◽  
Antiviral Efficacy ◽  
Prevention And Treatment ◽  
Proven Efficacy ◽  
High Antiviral Activity

Introduction. The pandemic spread of a new coronavirus infection, COVID-19, has caused a global emergency and attracted the attention of public health professionals and the population of all countries. A significant increase in the number of new cases of SARS-CoV-2 infection demonstrates the urgency of finding drugs effective against this pathogen.The aim of this work was to evaluate the in vitro antiviral efficacy of human recombinant alpha-2b interferon (IFN-α2b) against SARS-CoV-2 virus.Material and methods. The experiments had been carried out on Vero Cl008, the continuous line of African green monkey (Chlorocebus sabaeus) kidney cells. The effectiveness of the drugs was assessed by the suppression of viral reproduction in vitro. The biological activity was determined using titration of a virus-containing suspension in a Vero Cl008 cell culture by the formation of negative colonies.Results. The antiviral efficacy of the IFN-α2b-based medications, which have a high safety profile and proven efficacy in the prevention and treatment of influenza and acute respiratory viral infections (ARVI), has been studied against the new pandemic SARS-CoV-2 virus in vitro experiments in Vero C1008 cell culture. IFN-α2b effectively inhibits the reproduction of the virus when applied both 24 hrs before and 2 hrs after infection. In the IFN-α2b concentration range 102–106 IU/ml a complete suppression of the reproduction of the SARS-CoV-2 virus had been demonstrated.Discussion. IFN-α2b demonstrated in vitro high antiviral activity against SARS-CoV-2. In addition, the substance has a high chemotherapeutic index (>1000).Conclusion. Medications for intranasal use based on IFN-α2b have high antiviral activity and are promising drugs for in vivo study in terms of prevention and treatment of COVID-19.

scholarly journals Evaluation of HIV-1 latency reversal and antibody-dependent viral clearance by quantification of singly spliced HIV-1 vpu/env mRNA

2021 ◽  
Author(s):  
Hongbo Gao ◽  
Ayşe N. Ozantürk ◽  
Qiankun Wang ◽  
Gray H. Harlan ◽  
Aaron J. Schmitz ◽  
...  
Keyword(s):  
T Cells ◽  
Neutralizing Antibodies ◽  
Ex Vivo ◽  
Viral Envelope ◽  
Latent Reservoir ◽  
Broadly Neutralizing Antibodies ◽  
Major Barrier ◽  
Hiv 1 ◽  
Reversing Agents

The latent reservoir of HIV-1 is a major barrier for viral eradication. Potent HIV-1 broadly neutralizing antibodies (bNabs) have been used to prevent and treat HIV-1 infections in animal models and clinical trials. Combination of bNabs and latency-reversing agents (LRAs) is considered a promising approach for HIV-1 eradication. PCR-based assays that can rapidly and specifically measure singly spliced HIV-1 vpu/env mRNA are needed to evaluate the induction of the viral envelope production at the transcription level and bNab-mediated reservoir clearance. Here we reported a PCR-based method to accurately quantify the production of intracellular HIV-1 vpu/env mRNA. With the vpu/env assay, we determined the LRA combinations that could effectively induce vpu/env mRNA production in CD4+ T cells from ART-treated individuals. None of the tested LRAs were effective alone. A comparison between the quantitative viral outgrowth assay (Q-VOA) and the vpu/env assay showed that vpu/env mRNA production was closely associated with the reactivation of replication-competent HIV-1, suggesting that vpu/env mRNA was mainly produced by intact viruses. Finally, antibody-mediated in vitro killing in HIV-1-infected humanized mice demonstrated that the vpu/env assay could be used to measure the reduction of infected cells in tissues and was more accurate than the commonly used gag-based PCR assay which measured unspliced viral genomic RNA. In conclusion, the vpu/env assay allows convenient and accurate assessment of HIV-1 latency reversal and bNab-mediated therapeutic strategies. Importance HIV-1 persists in individuals on antiretroviral therapy (ART) due to the long-lived cellular reservoirs that contain dormant viruses. Recent discoveries of HIV-1-specific broadly neutralizing antibodies (bNabs) targeting HIV-1 Env protein rekindled the interest in antibody-mediated elimination of latent HIV-1. Latency-reversing agents (LRAs) together with HIV-1 bNabs is a possible strategy to clear residual viral reservoirs, which makes the evaluation of HIV-1 Env expression upon LRA treatment critical. We developed a PCR-based assay to quantify the production of intracellular HIV-1 vpu/env mRNA. Using patient CD4+ T cells, we found that induction of HIV-1 vpu/env mRNA required a combination of different LRAs. Using in vitro, ex vivo and humanized mouse models, we showed that the vpu/env assay could be used to measure antibody efficacy in clearing HIV-1 infection. These results suggest that the vpu/env assay can accurately evaluate HIV-1 reactivation and bNab-based therapeutic interventions.

scholarly journals Trichomonas vaginalis Lipophosphoglycan Mutants Have Reduced Adherence and Cytotoxicity to Human Ectocervical Cells

2005 ◽  
Vol 4 (11) ◽  
pp. 1951-1958 ◽  
Author(s):  
Felix D. Bastida-Corcuera ◽  
Cheryl Y. Okumura ◽  
Angie Colocoussi ◽  
Patricia J. Johnson
Keyword(s):  
Wheat Germ Agglutinin ◽  
Parent Strain ◽  
Trichomonas Vaginalis ◽  
Wheat Germ ◽  
Polyacrylamide Gel Electrophoresis ◽  
Sodium Dodecyl ◽  
Host Cells ◽  
Chemical Mutagenesis ◽  
Reduced Adherence

ABSTRACT The extracellular human pathogen Trichomonas vaginalis is covered by a dense glycocalyx thought to play a role in host-parasite interactions. The main component of the glycocalyx is lipophosphoglycan (LPG), a polysaccharide anchored in the plasma membrane by inositol phosphoceramide. To study the role of LPG in trichomonads, we produced T. vaginalis LPG mutants by chemical mutagenesis and lectin selection and characterized them using morphological, biochemical, and functional assays. Two independently selected LPG mutants, with growth rates comparable to that of the wild-type (parent) strain, lost the ability to bind the lectins Ricinnus comunis agglutinin I (RCA120) and wheat germ agglutinin, indicating alterations in surface galactose and glucosamine residues. LPG isolated from mutants migrated faster than parent strain LPG on sodium dodecyl sulfate-polyacrylamide gel electrophoresis, suggesting the mutants had shorter LPG molecules. Dionex high-performance anion exchange chromatography with pulsed amperometric detection analyses revealed galactosamine, glucosamine, galactose, glucose, mannose/xylose, and rhamnose as the main monosaccharides of T. vaginalis parent strain LPG. LPG from both mutants showed a reduction of galactose and glucosamine, corresponding with the reduced size of their LPG molecules and inability to bind the lectins RCA120 and wheat germ agglutinin. Mutant parasites were defective in attachment to plastic, a characteristic associated with avirulent strains of T. vaginalis. Moreover, the mutants were less adherent and less cytotoxic to human vaginal ectocervical cells in vitro than the parental strain. Finally, while parent strain LPG could inhibit the attachment of parent strain parasites to vaginal cells, LPG from either mutant could not inhibit attachment. These combined results demonstrate that T. vaginalis adherence to host cells is LPG mediated and that an altered LPG leads to reduced adherence and cytotoxicity of this parasite.

scholarly journals Functional Role of N-Linked Glycosylation in Pseudorabies Virus Glycoprotein gH

2018 ◽  
Vol 92 (9) ◽  
pp. e00084-18 ◽  
Author(s):  
Melina Vallbracht ◽  
Sascha Rehwaldt ◽  
Barbara G. Klupp ◽  
Thomas C. Mettenleiter ◽  
Walter Fuchs
Keyword(s):  
Pseudorabies Virus ◽  
Viral Envelope ◽  
Fusion Activity ◽  
Virus Particles ◽  
Glycosylation Sites ◽  
Functional Relevance ◽  
And Function ◽  
Cell Spread

ABSTRACTMany viral envelope proteins are modified by asparagine (N)-linked glycosylation, which can influence their structure, physicochemical properties, intracellular transport, and function. Here, we systematically analyzed the functional relevance of N-linked glycans in the alphaherpesvirus pseudorabies virus (PrV) glycoprotein H (gH), which is an essential component of the conserved core herpesvirus fusion machinery. Upon gD-mediated receptor binding, the heterodimeric complex of gH and gL activates gB to mediate fusion of the viral envelope with the host cell membrane for viral entry. gH contains five potential N-linked glycosylation sites at positions 77, 162, 542, 604, and 627, which were inactivated by conservative mutations (asparagine to glutamine) singly or in combination. The mutated proteins were tested for correct expression and fusion activity. Additionally, the mutated gH genes were inserted into the PrV genome for analysis of function during virus infection. Our results demonstrate that all five sites are glycosylated. Inactivation of the PrV-specific N77 or the conserved N627 resulted in significantly reducedin vitrofusion activity, delayed penetration kinetics, and smaller virus plaques. Moreover, substitution of N627 greatly affected transport of gH in transfected cells, resulting in endoplasmic reticulum (ER) retention and reduced surface expression. In contrast, mutation of N604, which is conserved in theVaricellovirusgenus, resulted in enhancedin vitrofusion activity and viral cell-to-cell spread. These results demonstrate a role of the N-glycans in proper localization and function of PrV gH. However, even simultaneous inactivation of all five N-glycosylation sites of gH did not severely inhibit formation of infectious virus particles.IMPORTANCEHerpesvirus infection requires fusion of the viral envelope with cellular membranes, which involves the conserved fusion machinery consisting of gB and the heterodimeric gH/gL complex. The bona fide fusion protein gB depends on the presence of the gH/gL complex for activation. Viral envelope glycoproteins, such as gH, usually contain N-glycans, which can have a strong impact on their folding, transport, and functions. Here, we systematically analyzed the functional relevance of all five predicted N-linked glycosylation sites in the alphaherpesvirus pseudorabies virus (PrV) gH. Despite the fact that mutation of specific sites affected gH transport,in vitrofusion activity, and cell-to-cell spread and resulted in delayed penetration kinetics, even simultaneous inactivation of all five N-glycosylation sites of gH did not severely inhibit formation of infectious virus particles. Thus, our results demonstrate a modulatory but nonessential role of N-glycans for gH function.

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