Bacteriophage MS2 Research Articles

Can prechlorination improve the permeate flux and water quality of gravity-driven membrane (GDM) filtration?

Gravity-driven membrane (GDM) filtration is currently limited by the relatively low permeate flux and poor water quality. This study was aimed to investigate the effects of prechlorination (3 and 5 mgCl2/L) on the permeate flux and water quality in GDM filtration by analyzing the compositions and morphologies of the fouling layer and by evaluating virus removal and trihalomethane (THM) formation for short (7 cycles) and long (32 cycles) periods. Prechlorination showed an increased permeate flux, contributing to enhanced cumulative water production (15–68%), which was achieved by lowering the extracellular polymeric substances (EPS) content (14–31%) and the formation of a relatively thinner and looser fouling layer. Prechlorination effects lessened with longer GDM operation time owing to bacterial regrowth and formation of a thick (178–227%) and dense (57–66%) fouling layer. It also changed the dominant phylum in the eukaryotic community and limited its activities in the fouling layer. In terms of the permeate water quality, the prechlorination ensured microbial safety with a 3.2 log10 reduction of MS2 bacteriophage and negligible formation of THMs. These results demonstrate the potential of using prechlorination in GDM filtration for sustainable drinking water treatment.

Effects of varying flux and transmembrane pressure conditions during ceramic ultrafiltration on the infectivity and retention of MS2 bacteriophages

.Membrane ultrafiltration (UF) constitutes a promising technology to remove viruses including phages from water. However, the removal efficiency of viruses such as MS2 phages strongly depends on operational parameters, such as flux and transmembrane pressure (TMP) conditions during UF. Initially, we investigated during this lab-scale study if the infectivity of MS2 phages was impaired at very high fluxes and the associated high TMPs during ceramic membrane UF The ratio of plaque forming units (PFU) indicating infectious MS2 phages and the total amount (infectious and non-infectious) of MS2 phages measured via digital polymerase chain reaction (dPCR) remained constant at varying fluxes. Hence, we concluded that the infectivity of MS2 phages was not significantly affected. Secondly, a trend analysis of PFUs and dPCR results during varying flux/TMP. conditions was performed. It was found that with increasing fluxes/TMPs, the retention of MS2 phages significantly increased Enhanced aggregation of the MS2 phages was expected to improve the size exclusion effect during ceramic UF while enlargement of ceramic membrane pores could be ruled out. Our findings partially contradict investigations with polymeric UF membranes. Possible underlying mechanisms were comprehensively discussed.

Electrochemical Biosensors Based on Convectively Assembled Colloidal Crystals.

Rapid, sensitive, selective and portable virus detection is in high demand globally. However, differentiating non-infectious viral particles from intact/infectious viruses is still a rarely satisfied sensing requirement. Using the negative space within monolayers of polystyrene (PS) spheres deposited directly on gold electrodes, we fabricated tuneable nanochannels decorated with target-selective bioreceptors that facilitate the size-selective detection of intact viruses. Detection occurred through selective nanochannel blockage of diffusion of a redox probe, [Fe(CN)6]3/4−, allowing a quantifiable change in the oxidation current before and after analyte binding to the bioreceptor immobilised on the spheres. Our model system involved partial surface passivation of the mono-assembled PS spheres, by silica glancing angle deposition, to confine bioreceptor immobilisation specifically to the channels and improve particle detection sensitivity. Virus detection was first optimised and modelled with biotinylated gold nanoparticles, recognised by streptavidin immobilised on the PS layer, reaching a low limit of detection of 37 particles/mL. Intact, label-free virus detection was demonstrated using MS2 bacteriophage (~23–28 nm), a marker of microbiological contamination, showing an excellent limit of detection of ~1.0 pfu/mL. Tuneable nanochannel geometries constructed directly on sensing electrodes offer label-free, sensitive, and cost-efficient point-of-care biosensing platforms that could be applied for a wide range of viruses.

PB2281: HOW TO AVOID FALSE-NEGATIVE AND FALSE-POSITIVE COVID-19 PCR TESTING

Background: Since early 2020 the most demanded molecular genetic test is real-time reverse transcription polymerase chain reaction (RT-PCR) for SARS-CoV-2. However, up to 40% of test results for COVID-19 in the presence of clinical manifestations of the disease might be negative. A false-negative analysis means untimely treatment of the patient and the possible spread of infection from a non-isolated person. Despite the fact that there are many highly sensitive RT-PCR test systems for COVID-19 on the market, the search for new reliable approaches to increase the robustness of testing is still relevant. Aims: To develop a PCR testing approach featured to minimize the risk of the false-negative results and to increase assay sensitivity and specificity by the use of multiple targets. Methods: A cotton swab taken from the nasopharynx was placed in an Eppendorf tube with 300 μl of phosphate-buffered saline. The resulting suspension (100 μl) was taken for RNA isolation using the Riboprep Amplisens kit (InterlabService, Russia). Primer sequences for RT-PCR are shown in Table 1. Results: The reason for a false-negative result might originate from any stage of the analysis: poor-quality or empty swab, poor RNA isolation, inactivation of reverse transcriptase or Taq polymerase in the test. To control the entire process usually control DNA or an RNA-containing virus (eg bacteriophage MS-2) is added to the sample before RNA isolation. This is sufficient to control RNA isolation, reverse transcription, and PCR amplification. However, improper swab application, handling, transporting, or even attempts to falsify the sample, cannot be excluded this way. Here we propose to include primers for the detection of human ABL1 gene RNA to control swab quality and integrity. Designed primers work with the cDNA of the ABL1 gene, not genomic DNA. Therefore achieved ABL1 gene amplification ensures that enough material containing host RNA was taken by the swab, RNA was nicely isolated, reverse transcribed, and PCR-amplified. For SARS-CoV-2 detection, we propose to use primers targeted to the conserved region of the nucleocapsid gene and the less conserved region of the spike gene (currently specific for the Omicron strain). The simultaneous appearance of three signals corresponding to the nucleocapsid, spike, and ABL1 gene indicates infection with the Omicron strain. The amplification of ABL1 gene and nucleocapsid only indicate other than Omicron infection. The appearance of ABL1 amplification only indicates a true negative result for SARS-CoV-2. All other variants are null and void. Image:Summary/Conclusion: A system has been developed for multiplex PCR diagnostics of SARS-CoV-2, which makes it possible to eliminate errors leading to false-negative and false-positive results at all stages of analysis. This is accomplished by the presence of specific primers for human RNA, controlling proper swab application, handling, and all the stages of RT-PCR. Targeting diverse regions of SARS-CoV-2 increases the reliability of the results and makes it possible to identify the virus strain.

Recycling of aged RO membranes as NF/UF membranes: Biosafety evaluation and aging process

With dramatic growth of reverse osmosis (RO) in water treatment, more than 1.5 million waste RO membrane modules will be generated worldwide annually, which will lead to waste of resources and environmental pollution if not properly disposed. The present study aims at evaluating the feasibility of using aged RO membranes in NF/UF process. And ultraviolet (UV) irradiation was used to simulate the aging process. In addition to the conventional separation performance, virus (bacteriophage MS2) removal rate was used to evaluate the ability that membranes ensure the biosafety of the permeate. After 48 h continuous UV irradiation (313 nm, 1 W/m2), the membrane maintained high Na2SO4 rejection (88%) and phage MS2 removal rate (>4 log), which was comparable to NF-like membrane. After 96 h, the membrane manifested sound virus removal rate (>3.4 log) and high pure water permeability (122.6 L·m−2·h−1·bar−1), but the ability for salt rejection was rather weak, which approximated to a UF-like membrane. It was noteworthy that the aged membrane maintained a high virus removal rate within 0–96 h, which ensured the biosafety of the permeate. The results provided a basis for direct recycling of aged membranes.

Comparison between the Biofilm Desorption Abilities of T4 and MS2 Coliphages

Biofilms are a collection of microorganisms that adhere to a surface where they continue to grow. Firmly established biofilms can be hazardous to human health. Chemical and biological as well as combination methods are being tested to control biofilms. The elucidation of the biofilm disruption capabilities of individual bacteriophages has received limited attention. Although the treatment of biofilms with a combination of bacteriophages is effective, the extent to which DNA and RNA coliphages individually desorb biofilms is not well understood. Here, we show that both T4 and MS2 coliphages desorbed natural biofilms. Individual incubations of the equivalent viral load of T4 and MS2 coliphages with natural biofilms resulted in similar desorption of these biofilms. We also note that the nutrient deprivation significantly reduced biofilm growth. However, the biofilm desorption upon nutrient deprivation was similar to that observed with both T4 and MS2 phages.

Visualizing Influenza A Virus vRNA Replication.

Influenza A virus (IAV) has caused recurrent epidemics and severe pandemics. In this study, we adapted an MS2-MCP live-cell imaging system to visualize IAV replication. A reporter plasmid, pHH-PB2-vMSL, was constructed by replacing a part of the PB2-coding sequence in pHH-PB2 with a sequence encoding 24 copies of a stem-loop structure from bacteriophage MS2 (MSL). Binding of MS2 coat protein (MCP) fused to green fluorescent protein (GFP) to MSL enabled the detection of vRNA as fluorescent punctate signals in live-cell imaging. The introduction of pHH-PB2-vMSL into A549 cells transduced to express an MCP-GFP fusion protein lacking the nuclear localization signal (MCP-GFPdN), subsequently allowed tracking of the distribution and replication of PB2-vMSL vRNA after IAV PR8 infection. Spatial and temporal measurements revealed exponential increases in vRNA punctate signal intensity, which was only observed after membrane blebbing in apoptotic cells. Similar signal intensity increases in apoptotic cells were also observed after MDCK cells, transduced to express MCP-GFPdN, were infected with IAV carrying PB2-vMSL vRNA. Notably, PB2-vMSL vRNA replication was observed to occur only in apoptotic cells, at a consistent time after apoptosis initiation. There was a lack of observable PB2-vMSL vRNA replication in non-apoptotic cells, and vRNA replication was suppressed in the presence of apoptosis inhibitors. These findings point to an important role for apoptosis in IAV vRNA replication. The utility of the MS2-imaging system for visualizing time-sensitive processes such as viral replication in live host cells is also demonstrated in this study.

Efficacy of the PlasmaShield®, a Non-Thermal, Plasma-Based Air Purification Device, in Removing Airborne Microorganisms

Airborne microorganisms play a significant role in the transmission of infectious diseases. As such, improving indoor microbial air quality can enhance infection control in numerous settings. This study examined the efficacy of the PlasmaShield® air purification device to remove airborne microorganisms under laboratory conditions. Pure cultures of model microorganisms at varying concentrations were aerosolized using a 1-jet Collison nebulizer through stainless-steel removable piping prior to reaching the PlasmaShield® device. The surviving microorganisms were captured using the Staplex® MBS-6 Six Stage Microbial Air Sampler and enumerated via culture on agar plates. The positive-hole-corrected colony/plaque-forming units were compared with the negative control (microorganisms aerosolized through an empty PlasmaShield® casing). The PlasmaShield® statistically significantly (p < 0.05) reduced airborne Escherichia coli, Staphylococcus epidermidis, Bacteriophage MS2 and Cladosporium sp. compared with the negative control. The maximum removal achieved was estimated to be 4 × log10E. coli (99.99% removal), 4 × log10S. epidermidis (99.97% removal), 7 × log10 MS2 (99.99998% removal) and 5 × log10Cladosporium sp. (99.999% removal). Scanning electron microscope images of the surviving microorganisms showed that the PlasmaShield® damaged the cell membrane of these model microorganisms. This study provides proof-of-concept evidence to support the use of this technology to improve indoor microbial air quality.

Novel sustainable filter for virus filtration and inactivation

The COVID-19 pandemic has caused a multi-scale impact on the world population that started from a nano-scale respiratory virus and led to the shutdown of macro-scale economies. Direct transmission of SARS-CoV-2 (Severe Acute Respiratory Syndrome Coronavirus 2) and its variants through aerosolized droplets is a major contributor towards increasing cases of this infection. To curb the spread, one of the best engineered solutions is the use of face masks to prevent the passage of infectious saliva micro-droplets from an infected person to a healthy person. The commercially available masks are single use, passive face-piece filters. These become difficult to breathe in during strenuous activities. Also, they need to be disposed regularly due to accumulation of unwanted particulate and pathogens over time. Frequent disposal of these masks is unsustainable for the environment. In this study, we have proposed a novel design for a filter for enhanced virus filtration, better breathability, and virus inactivation over time. The filter is called Hy–Cu named after its (Hy) drophobic properties and another significant layer comprises of copper (Cu). The breathability (pressure drop across filter) of Hy–Cu is tested and compared with widely used surgical masks and KN95 masks, both experimentally and numerically. The results show that the Hy–Cu filter offers at least 10% less air resistance as compared to commercially available masks. The experimental results on virus filtration and inactivation tests using MS2 bacteriophage (a similar protein structure as SARS-CoV-2) show that the novel filter has 90% filtering efficiency and 99% virus inactivation over a period of 2 h. This makes the Hy–Cu filter reusable and a judicious substitute to the single use masks.

Fabrication of SnO2-Sb reactive membrane electrodes for high-efficiency electrochemical inactivation of bacteria and viruses in water

Exposure to waterborne pathogens is still a widespread threat to public health, and efficient and reliable disinfection technologies are urgently needed for decentralized applications. Herein, we developed a novel freestanding and flow-through SnO2-Sb reactive membrane electrode (RME) for electrochemical wastewater disinfection. When water was forced to flow through the porous RME, large amounts of reactive ·OH and H+ were generated within the interior pores of the anode, creating a strongly acidic local environment enriched with ·OH for the rapid inactivation of bacteria and viruses. At an applied voltage of 3.5 V, 100% removal of Escherichia coli (>6.3-log inactivation) was achieved by the flow-through RME at a high flux, which was significantly more effective than the system operated in the conventional flow-by mode (2.7-log inactivation). Using the bacteriophage MS2 strain as a model virus, a disinfection efficiency of 100% (>8.3-log inactivation) was achieved by the RME at 3.5 V. The transmission electron microscopy analysis revealed that E. coli and MS2 in the disinfected water suffered from serious destruction and disintegration, reflecting the strong electrocatalytic oxidation capacity of the charged RME. The SnO2-Sb RME-based electrochemical system performed very well in disinfecting complex municipal wastewater, demonstrating its potential for practical applications.

Epitope-Based Vaccines against the Chlamydia trachomatis Major Outer Membrane Protein Variable Domain 4 Elicit Protection in Mice

Chlamydia trachomatis (Ct) is the most common bacterial sexual transmitted pathogen, yet a vaccine is not currently available. Here, we used the immunogenic bacteriophage MS2 virus-like particle (VLP) technology to engineer vaccines against the Ct major outer membrane protein variable domain 4 (MOMP-VD4), which contains a conserved neutralizing epitope (TTLNPTIAG). A previously described monoclonal antibody to the MOMP-VD4 (E4 mAb) is capable of neutralizing all urogenital Ct serovars and binds this core epitope, as well as several non-contiguous amino acids. This suggests that this core epitope may require conformational context in order to elicit neutralizing antibodies to Ct. In order to identify immunogens that could elicit neutralizing antibodies to the TTLNPTIAG epitope, we used two approaches. First, we used affinity selection with a bacteriophage MS2-VLP library displaying random peptides in a constrained, surface-exposed loop to identify potential E4 mAb mimotopes. After four rounds of affinity selection, we identified a VLP-displayed peptide (HMVGSTKWTN) that could bind to the E4 mAb and elicited serum IgG that bound weakly to Ct elementary bodies by ELISA. Second, two versions of the core conserved TTLNPTIAG epitope (TTLNPTIAG and TTLNPTIAGA) were recombinantly expressed on the coat protein of the MS2 VLP in a constrained, surface-exposed loop. Mouse immune sera IgG bound to Ct elementary bodies by ELISA. Immunization with these MS2 VLPs provided protection from vaginal Chlamydia infection in a murine challenge model. These data suggest that short peptide epitopes targeting the MOMP-VD4 could be appropriate for Ct vaccine design when displayed on an immunogenic bacteriophage VLP vaccine platform.

Effect of particulate matters on inactivation of bacteriophage MS2 under irradiation above 320nm.

The inactivation of bacteriophage MS2 under irradiation above 320nm was investigated, focusing on different solution pH, ionic strength, and Suwannee River natural organic matter (SRNOM) concentrations when solutions contained organic or inorganic particle matters. Inorganic and organic particles were modeled using kaolinite (KAO) and Microcystis aeruginosa (MA), respectively. The results showed that the two types of particles influenced on MS2 inactivation under different conditions. The lower pH contributed to the greater MS2 aggregation within pH range of 3.0 to 8.0, leading to an increasing inactivation rate. The presence of KAO induced reactive oxygen species (ROS) under the action of irradiation above 320nm, which promoted the inactivation of MS2. By comparison, the [Formula: see text] produced by MA after irradiation promoted the inactivation at pH < 6, whereas when the pH is ≥ 6, the inactivation effect of MS2 was lower than that of particle-free solution because MS2 was no longer aggregated and MA has a shading effect. In the presence of Na+ or Ca2+ cation, irradiation above 320nm could not effectively inactivate the MS2 under particle-free solution. By comparison, KAO increased the inactivation efficiency as a photosensitizer. With the increase of Ca2+ concentration, MS2 was more easily adsorbed to MA than aggregation. Until Ca2+ concentration reached 20mM, the inactivation effect in MA solution was enhanced. In the presence of SRNOM, the inactivation effect increased with the increase of SRNOM concentration. When the SRNOM was 20mM, the inactivation increased in the particle-free solution due to the greater production of [Formula: see text]. Compared with the particle-free solution, the KAO and MA inactivation efficiency was lower.

Lack of Cas13a inhibition by anti-CRISPR proteins from Leptotrichia prophages

CRISPR systems are prokaryotic adaptive immune systems that use RNA-guided Cas nucleases to recognize and destroy foreign genetic elements. To overcome CRISPR immunity, bacteriophages have evolved diverse families of anti-CRISPR proteins (Acrs). Recently, Lin etal. (2020) described the discovery and characterization of 7 Acr families (AcrVIA1-7) that inhibit type VI-A CRISPR systems. We detail several inconsistencies that question the results reported in the Lin etal. (2020) study. These include inaccurate bioinformatics analyses and bacterial strains that are impossible to construct. Published strains were provided by the authors, but MS2 bacteriophage plaque assays did not support the published results. We also independently tested the Acr sequences described in the original report, in E.coli and mammalian cells, but did not observe anti-Cas13a activity. Taken together, our data and analyses prompt us to question the claim that AcrVIA1-7 reported in Lin etal. are type VI anti-CRISPR proteins.

Photoelectrocatalytic degradation of pharmaceuticals and inactivation of viruses in water with tungsten oxide electrodes

Electrochemically assisted photocatalysis (EAP) is one approach to overcome the fast recombination rates in photocatalysis and increase the quantum efficiency to produce ROS. In comparison to TiO2, tungsten trioxide (WO3) can utilize UV and visible photons and with EAP the external bias can be used to drive the reduction pathway. In this work WO3 electrodes were prepared hydrothermally on FTO. Vertically grown WO3 nanoplate-like structures were thoroughly characterized. The WO3 photoanodes improved photocurrent response compared to P25 and a visible response was measured. These results were attributed to smaller charge transfer resistance and their morphology. The activity of the photoanodes was assessed on the EAP degradation of sulfamethoxazole and MS2 bacteriophage. WO3 yielded ten times higher degradation rates for sulfamethoxazole (2.21 · 10−6 mmol cm−2 min−1) compared to P25. WO3 also yielded the fastest MS2 inactivation rate. A rapid 5-log removal was achieved in 6 min with WO3 that maintained activity over 5 cycles.

Evaluation of adsorption-elution methods with positively and negatively charged membranes for virus concentration in municipal wastewater: New insight into effects of dissolved organic matter

Efficient enrichment is the premise and guarantee for quantitative detection of pathogenic viruses in municipal wastewater. Some naturally occurring organic matter has an impact on the enrichment process because of interference with virus adsorption to the microporous membrane. In this study, the influence of dissolved organic matter (DOM) on the adsorption-elution method utilizing positively and negatively charged membranes for the recovery of bacteriophage MS2 in raw sewage and secondary effluent was investigated. For raw sewage and secondary effluent, the total recovery rate of virus with negatively charged membrane was 7.63% and 24.38% higher than that with positively charged membrane, respectively. Therefore, the adsorption-elution method with negatively charged membrane was suitable for raw sewage and secondary effluent. The recovery rate of elution step was lowest in all stages of adsorption-elution method, so the elution step was limiting step in the recovery of bacteriophage MS2 by adsorption-elution method. Fourier transform infrared spectroscopy (FTIR) with the fluorescence excitation-emission matrix spectroscopy (EEM) analysis revealed that tryptophan was dominant in the raw sewage, and humic acid (HA) was dominant in secondary effluent. Moreover, the surface roughness of the fouled membrane in the presence of tryptophan was higher than that of HA based on the morphology analysis by atomic force microscopy (AFM). According to X-ray photoelectron spectroscopy (XPS) analysis, the contribution of main functional groups in tryptophan and HA to the elution efficiency of bacteriophage MS2 was identified. In addition, the elution of bacteriophage MS2 was easy in the presence of tryptophan due to electrostatic force, and covalent bond / hydrogen bond in the presence of HA make bacteriophage MS2 difficult to be eluted. These findings can offer some evidence and scientific support for the standardization of enrichment methods in the water sample.

The Overlooked Photochemistry of Iodine in Aqueous Suspensions of Fullerene Derivatives.

Fullerene’s low water solubility was a serious challenge to researchers aiming to harness their excellent photochemical properties for aqueous applications. Cationic functionalization of the fullerene cage provided the most effective approach to increase water solubility, but common synthesis practices inadvertently complicated the photochemistry of these systems by introducing iodide as a counterion. This problem was overlooked until recent work noted a potentiation effect which occurred when photosensitizers were used to inactivate microorganisms with added potassium iodide. In this work, several photochemical pathways were explored to determine the extent and underlying mechanisms of iodide’s interference in the photosensitization of singlet oxygen by cationic fulleropyrrolidinium ions and rose bengal. Triplet excited state sensitizer lifetimes were measured via laser flash photolysis to probe the role of I– in triplet sensitizer quenching. Singlet oxygen production rates were compared across sensitizers in the presence or absence of I–, SO42–, and other anions. 3,5-Dimethyl-1H-pyrazole was employed as a chemical probe for iodine radical species, such as I·, but none were observed in the photochemical systems. Molecular iodine and triiodide, however, were found in significant quantities when photosensitizers were irradiated in the presence of I– and O2. The formation of I2 in these photochemical systems calls into question the interpretations of prior studies that used I– as a counterion for photosensitizer materials. As an example, MS2 bacteriophages were inactivated here by cationic fullerenes with and without I– present, showing that I– moderately accelerated the MS2 deactivation, likely by producing I2. Production of I2 did not appear to be directly correlated with estimates of 1O2 concentration, suggesting that the relevant photochemical pathways are more complex than direct reactions between 1O2 and I– in the bulk solution. On the basis of the results here, iodine photochemistry may be underappreciated and misunderstood in other environmental systems.

Waterline Disinfectants Reduce Dental Bioaerosols: A Multitracer Validation

Oral microbes are dispersed during dental treatment and reduction methods have been proposed, but dental unit waterline (DUWL) disinfectants have received little attention; specifically, the effect on viruses has not been studied. This study aims to 1) investigate the effect of DUWL disinfectants on viral dispersion in dental bioaerosols and 2) establish a dual-tracer system using live bacteriophage and fluorescein supported by optical particle measurement. Bacteriophage MS2 was used as a viral tracer and fluorescein as a fluorescent tracer. Validation experiments were conducted to exclude interference of one tracer with the other or of DUWL disinfectants on detection methods. Simulated “saliva” containing the tracers was infused into the mouth of a dental mannequin during 10-min dental procedures with an air turbine handpiece (n = 3 replicates). Aerosols and droplets were sampled in an enclosed dental operatory using air samplers and settlement onto sterile filter papers. Bacteriophage was quantified using plaque assays and reverse transcription quantitative polymerase chain reaction (RT-qPCR). Fluorescein was quantified fluorometrically. The effect of DUWL disinfectants on total aerosol concentration was assessed in separate experiments using an optical particle counter. DUWL disinfectants reduced bacteriophage viability, and interference between tracers was not observed. In simulated clinical procedures, the disinfectant ICX reduced bacteriophage detection substantially (P < 0.001; 2-way analysis of variance). MS2 RNA was detected in all experimental samples but not negative controls. Samples positive on RT-qPCR but not plaque assays may indicate that virions at distant sites are nonviable. Fluorescein tracer showed good agreement with the bacteriophage tracer. DUWL disinfectants designed for continuous presence in irrigants reduce the dispersion of viable virus in dental bioaerosols during simulated procedures. Their use may therefore be important for routine infection control and as a mitigation factor during infectious disease outbreaks. Future studies should explore this using a range of viruses and other microbes.

UPF1 promotes rapid degradation of m6A-containing RNAs

N6-methyladenosine (m6A) is the most prevalent internal modification in eukaryotic mRNAs and affects RNA processing and metabolism. When YTHDF2, an m6A-recognizing protein, binds to m6A, it facilitates the destabilization of m6A-containing RNAs (m6A RNAs). Here, we demonstrate that upstream frameshift 1 (UPF1), a key factor for nonsense-mediated mRNA decay, interacts with YTHDF2, thereby triggering rapid degradation of m6A RNAs. The UPF1-mediated m6A RNA degradation depends on a specific interaction between UPF1 and N-terminal residues 101-168 of YTHDF2, UPF1 ATPase/helicase activities, and UPF1 interaction with proline-rich nuclear receptor coactivator 2 (PNRC2), a decapping-promoting factor preferentially involved in nonsense-mediated mRNA decay. Furthermore, transcriptome-wide analyses show that YTHDF2-bound mRNAs that are not substrates for HRSP12-RNase P/MRP-mediated endoribonucleolytic cleavage are destabilized with a higher dependency on UPF1. Collectively, our data indicate dynamic and multilayered regulation of the stability of m6A RNAs and highlight the multifaceted role of UPF1 in mRNA decay.

Experimental Study of Antitumor Activity of Pefagtal Addressed to αvβ3 Integrins.

We studied the effect of a new targeted drug Pefagtal that represents a conjugate in which the MS2 phage filled with a substance toxic to cells (thallium salts) is covalently linked to peptides containing the RGD motif. The antitumor and pronounced antimetastatic effects of Pefagtal were demonstrated on transplanted mouse tumors differing in histological type and status of metastasis: Krebs-2 ascites adenocarcinoma of the mammary gland, Lewis lung adenocarcinoma, hepatoma-29, and lung adenocarcinoma. It is assumed that the RGD motif mediates primary binding of the construct to αvβ3 and αvβ5 integrins that are predominantly overexpressed in the endothelial cells of tumor blood vessels and in tumor and metastatic cells.

Removal of MS2 and fr Bacteriophages Using MgAl2O4-Modified, Al2O3-Stabilized Porous Ceramic Granules for Drinking Water Treatment.

Point-of-use ceramic filters are one of the strategies to address problems associated with waterborne diseases to remove harmful microorganisms in water sources prior to its consumption. In this study, development of adsorption-based ceramic depth filters composed of alumina platelets was achieved using spray granulation (calcined at 800 °C). Their virus retention performance was assessed using cartridges containing granular material (4 g) with two virus surrogates: MS2 and fr bacteriophages. Both materials showed complete removal, with a 7 log10 reduction value (LRV) of MS2 up to 1 L. MgAl2O4-modified Al2O3 granules possessed a higher MS2 retention capacity, contrary to the shortcomings of retention limits in pure Al2O3 granules. No significant decline in the retention of fr occurred during filtration tests up to 2 L. The phase composition and morphology of the materials were preserved during filtration, with no magnesium or aluminum leakage during filtration, as confirmed by X-ray diffractograms, electron micrographs, and inductively coupled plasma-optical emission spectrometry. The proposed MgAl2O4-modified Al2O3 granular ceramic filter materials offer high virus retention, achieving the criterion for virus filtration as required by the World Health Organization (LRV ≥ 4). Owing to their high thermal and chemical stability, the developed materials are thus suitable for thermal and chemical-free regeneration treatments.