Bacteriophage Φ29 Research Articles

Optimizing RT-qPCR Detection of Enveloped and Non-enveloped Viruses in Wastewater: A Comparative Study in Grenada

Abstract Introduction/Objective Wastewater-based epidemiology (WBE) is an effective methodology to monitor the community spread of pathogens and has successfully been used to identify potential outbreaks. Most standardized methodologies used in WBE for the detection of viruses have been validated for non-enveloped viruses; therefore, there is a need for the development of a standardized protocol for the detection of both enveloped (such as SARS- CoV-2) and non-enveloped viruses (such as Hepatitis A). Wastewater seeded with Pseudomonas syringae bacteriophage (Φ6), an enveloped virus surrogate, and coliphage MS2, a non-enveloped virus surrogate, were used to evaluate the efficiency of four different aluminium flocculation methods. Untreated wastewater spiked with known amounts of surrogates was used as a control for viral recovery. Methods/Case Report Four different viral concentration methods were used. Method 1: AlCl3 flocculation at pH 3.5 followed by centrifugation, resuspension with 10% beef extract and filtered with a 0.22 μm filter. Method 2: AlCl3 flocculation at pH 6.0 followed by room temperature agitation, centrifugation, and resuspension with 3% beef extract. Method 3: Mixed method protocol-AlCl3 flocculation at pH 3.5 followed by room temperature agitation, centrifugation, resuspension with 3% beef extract. Method 4: Mixed method protocol-AlCl3 flocculation at pH 6.0 followed by centrifugation, resuspension with 10% beef extract filtered with a 0.22 μm filter. Viral RNA was extracted after concentration, and reverse-transcription quantitative polymerase chain reaction (RT- qPCR) was performed. Results (if a Case Study enter NA) The average Ct reduction of untreated wastewater compared to spiked was calculated for each method. The highest recovery of both Φ6 and MS2 was obtained using Method 3 (mixed protocol) with a significant difference at 95% confidence in the recovery of Φ6 (p= 0.0029) and MS2 (p= 0.0225). Conclusion Previous results from our lab demonstrate the importance of pH during the flocculation step of viral concentration using different methods of concentration. Here, the results suggest that the increased contact time between virus and the flocs is also critical. This can facilitate the implementation of WBE in Grenada to monitor and track potential viral outbreaks of both enveloped and non-enveloped viruses such as SARS-CoV-2 and Hepatitis A.

Origin, Evolution and Diversity of φ29-like Phages-Review and Bioinformatic Analysis.

Phage φ29 and related bacteriophages are currently the smallest known tailed viruses infecting various representatives of both Gram-positive and Gram-negative bacteria. They are characterised by genomic content features and distinctive properties that are unique among known tailed phages; their characteristics include protein primer-driven replication and a packaging process characteristic of this group. Searches conducted using public genomic databases revealed in excess of 2000 entries, including bacteriophages, phage plasmids and sequences identified as being archaeal that share the characteristic features of phage φ29. An analysis of predicted proteins, however, indicated that the metagenomic sequences attributed as archaeal appear to be misclassified and belong to bacteriophages. An analysis of the translated polypeptides of major capsid proteins (MCPs) of φ29-related phages indicated the dissimilarity of MCP sequences to those of almost all other known Caudoviricetes groups and a possible distant relationship to MCPs of T7-like (Autographiviridae) phages. Sequence searches conducted using HMM revealed the relatedness between the main structural proteins of φ29-like phages and an unusual lactococcal phage, KSY1 (Chopinvirus KSY1), whose genome contains two genes of RNA polymerase that are similar to the RNA polymerases of phages of the Autographiviridae and Schitoviridae (N4-like) families. An analysis of the tail tube proteins of φ29-like phages indicated their dissimilarity of the lower collar protein to tail proteins of all other viral groups, but revealed its possible distant relatedness with proteins of toxin translocation complexes. The combination of the unique features and distinctive origin of φ29-related phages suggests the categorisation of this vast group in a new order or as a new taxon of a higher rank.

Wipe Disinfection of Reusable Elastomeric Half-Mask Respirators for Health Care Use.

During shortages, elastomeric half-mask respirators (EHMRs) are an alternative to reusing N95 filtering facepiece respirators but require between-use disinfection. The objectives of this study were to (a) measure microbial reductions on EHMR surfaces under laboratory conditions by a standardized procedure using wipes impregnated with health care disinfectants and to (b) measure microbial reductions on EHMRs disinfected by volunteer health care providers. We inoculated EHMR (Honeywell model RU8500) surfaces with Pseudomonas aeruginosa, Bacillus atrophaeus spores, and bacteriophages MS2 and Φ6, and disinfected them using two wipes with hydrogen peroxide (HP), alcohols, and quaternary ammonium compounds (QACs). Then, we randomized 54 volunteer subjects into three groups (Group 1: two wipes with instructions, Group 2: five wipes with instructions, Group 3: no instructions or set number of wipes) and used 0.5% HP wipes without precleaning on EHMRs inoculated with Raoultella terrigena and MS2. The laboratory study demonstrated that all organisms achieved at least 4 log10 median reductions (HP>QAC/alcohol>QAC>QAC/saline). Pseudomonas was highly susceptible to HP and QAC/alcohol and Φ6 to all disinfectants. MS2 reduction was highest using HP and lowest using QAC/saline. Bacillus was least susceptible. The volunteer study showed a 3 to 4 log10 average reductions of bacteria and virus; Raoultella reductions were greater than MS2, with variability within and between subjects. Conclusions: HP disinfectant wipes used in laboratory and by volunteers reduce bacteria and viruses on EHMRs by 3 to 4 log10 on average. Commercially available hospital disinfectant wipes reduce bacteria and viruses on EHMRs and can fill the need for between-use disinfection. HP and combination QAC/alcohol have the greatest efficacy under our test conditions.

SARS-CoV-2 surrogate bacteriophage φ6 cross-contamination between fruits and gloves, survival on discarded gloves and inactivation by photodynamic treatment

This study assessed the SARS-CoV-2 surrogate bacteriophage φ6 cross-contamination between high-density polyethylene or polyvinyl chloride gloves and fruits (tomato and cucumber) using different inoculum levels (6.0 and 4.0 log PFU/sample). Bacteriophage φ6 survival on contaminated gloves was assessed over 9 days at 25 °C. The effectiveness of photodynamic treatment using curcumin as a photosensitizer to inactivate φ6 on fruits was determined. The fruit type and the glove material influenced the φ6 transfer. Longer contact times resulted in greater φ6 transfer. The highest φ6 transfer occurred from tomato to HDPE glove (0.8% or −1.1 log % transfer) after 30 s of contact at the higher inoculum level. Bacteriophage φ6 was detected on cross-contaminated HDPE gloves for up to 6 days. Bacteriophage φ6 survived better on vinyl gloves cross-contaminated by cucumber vs. tomato (detected up to 6 vs 3 days). Photodynamic inactivation of φ6 was time-dependent and varied with the tested fruit but was not influenced by viral starting concentration. Photodynamic treatment decreased the φ6 titer by 3.0 and 2.2 log PFU/sample in tomato and cucumber, respectively. Transmission electronic microscopy showed that photodynamic treatment changed the structure of the φ6 capsid. These findings may help in the management of SARS-CoV-2 contamination risks in fruit handling. They may also help in the establishment of effective measures to manage cross-contamination risk.

Antibacterial and antiviral activities of transparent PVA coating films prepared by using solutions containing eluted ions from rare earth iodates

AbstractAfter powders of three rare earth iodates (Ce(IO3)4, Ce(IO3)3, δ-La(IO3)3) were dispersed in water, the constituent ions were eluted. After filtration, polyvinyl alcohol was dissolved in the filtrated solution. Then the solution was flow-coated to form coating films on glass substrates. The obtained coating films exhibited high transmittance in the visible wavelength range. IO3− was confirmed from the IR spectra measured using the ATR method. Fine precipitates were observed in the coating. The amount was greater on the surface than inside. The coating films prepared from Ce(IO3)3 and δ-La(IO3)3 possessed high antibacterial and antiviral activities against Escherichia coli, Staphylococcus aureus, bacteriophage Qβ, and bacteriophage Φ6 in the dark. Moreover, they inactivated viruses adsorbed from the gas phase.

Benefits of Core-Shell Particles over Single-Metal Coatings: Mechanical and Chemical Exposure and Antimicrobial Efficacy.

One of the greatest challenges worldwide is containing the spread of problematic microorganisms. A promising approach is the use of antimicrobial coatings (AMCs). The antimicrobial potential of certain metals, including copper and zinc, has already been verified. In this study, polyethylene terephthalate and aluminum (PET-Al) foils were coated with copper, zinc, and a combination of these two metals, known as core-shell particles, respectively. The resistance of the three different types of coatings to mechanical and chemical exposure was evaluated in various ways. Further, the bacteria Staphylococcus aureus and the bacteriophage ϕ6 were used to assess the antimicrobial efficacy of the coatings. The best efficacy was achieved with the pure copper coating, which was not convincing in the abrasion tests. The result was a considerable loss of copper particles on the surfaces and reduced effectiveness against the microorganisms. The core-shell particles demonstrated better adhesion to the surfaces after abrasion tests and against most chemical agents. In addition, the antimicrobial efficiency remained more stable after the washability treatment. Thus, the core-shell particles had several benefits over the pure copper and zinc coatings. In addition, the best core-shell loading for durability and efficacy was determined in this study.

Microbe Profile: Bacteriophage ϕ6: a model for segmented RNA viruses and the evolutionary consequences of viral 'sex'.

Bacteriophage ϕ6 is a segmented dsRNA virus with a lipid envelope, which are unusual traits in bacterial viruses but common in eukaryotic viruses. This uniqueness allowed ϕ6 and its Pseudomonad hosts to serve as a molecular model for RNA genetics, mutation, replication, packaging, and reassortment in both bacterial and eukaryotic viruses. However, an additional uniqueness of ϕ6, created by its high mutation rate, was its use as an experimental system to study key questions such as the evolution of sex (segment reassortment), host-pathogen interactions, mutational load, rates of adaptation, genetic and phenotypic complexity, and game theory.

Experimental Evolution Studies in Φ6 Cystovirus.

Experimental evolution studies, in which biological populations are evolved in a specific environment over time, can address questions about the nature of spontaneous mutations, responses to selection, and the origins and maintenance of novel traits. Here, we review more than 30 years of experimental evolution studies using the bacteriophage (phage) Φ6 cystovirus. Similar to many lab-studied bacteriophages, Φ6 has a high mutation rate, large population size, fast generation time, and can be genetically engineered or cryogenically frozen, which facilitates its rapid evolution in the laboratory and the subsequent characterization of the effects of its mutations. Moreover, its segmented RNA genome, outer membrane, and capacity for multiple phages to coinfect a single host cell make Φ6 a good non-pathogenic model for investigating the evolution of RNA viruses that infect humans. We describe experiments that used Φ6 to address the fitness effects of spontaneous mutations, the consequences of evolution in the presence of coinfection, the evolution of host ranges, and mechanisms and consequences of the evolution of thermostability. We highlight open areas of inquiry where further experimentation on Φ6 could inform predictions for pathogenic viruses.

Antiviral and antibacterial activities of yttria-stabilized zirconia

Antiviral and antibacterial activities of yttria stabilized zirconia (YSZ) powder were evaluated against Escherichia coli, Staphylococcus aureus, bacteriophage Qβ, and bacteriophage Φ6 using ISO procedures. For comparison, the same evaluation was also conducted using Y2O3 and ZrO2 powders. Against all these bacteria and viruses, YSZ exhibited antibacterial and antiviral activities, but the extent of its activity differed depending on the bacteria and virus. Those differences in activity might be attributable to electrostatic interactions between the YSZ surface or ions and bacteria and viruses, the degree of adsorption attributable to specific interactions between Y or ZrO2 and phosphate ions, and differences in protein denaturation including lipid bilayer deformation.

Graph-theoretical prediction of biological modules in quaternary structures of large protein complexes.

The functional complexity of biochemical processes is strongly related to the interplay of proteins and their assembly into protein complexes. In recent years, the discovery and characterization of protein complexes have substantially progressed through advances in cryo-electron microscopy, proteomics, and computational structure prediction. This development results in a strong need for computational approaches to analyse the data of large protein complexes for structural and functional characterization. Here, we aim to provide a suitable approach, which processes the growing number of large protein complexes, to obtain biologically meaningful information on the hierarchical organization of the structures of protein complexes. We modelled the quaternary structure of protein complexes as undirected, labelled graphs called complex graphs. In complex graphs, the vertices represent protein chains and the edges spatial chain-chain contacts. We hypothesized that clusters based on the complex graph correspond to functional biological modules. To compute the clusters, we applied the Leiden clustering algorithm. To evaluate our approach, we chose the human respiratory complex I, which has been extensively investigated and exhibits a known biological module structure experimentally validated. Additionally, we characterized a eukaryotic group II chaperonin TRiC/CCT and the head of the bacteriophage Φ29. The analysis of the protein complexes correlated with experimental findings and indicated known functional, biological modules. Using our approach enables not only to predict functional biological modules in large protein complexes with characteristic features but also to investigate the flexibility of specific regions and coformational changes. The predicted modules can aid in the planning and analysis of experiments. Jupyter notebooks to reproduce the examples are available on our public GitHub repository: https://github.com/MolBIFFM/PTGLtools/tree/main/PTGLmodulePrediction.

Polypropylene-Rendered Antiviral by Three-Dimensionally Surface-Grafted Poly(N-benzyl-4-vinylpyridinium bromide).

To inhibit viral infection, it is necessary for the surface of polypropylene (PP), a polymer of significant industrial relevance, to possess biocidal properties. However, due to its low surface energy, PP weakly interacts with other organic molecules. The biocidal effects of quaternary ammonium compounds (QACs) have inspired the development of nonwoven PP fibers with surface-bound quaternary ammonium (QA). Despite this advancement, there is limited knowledge regarding the durability of these coatings against scratching and abrasion. It is hypothesized that the durability could be improved if the thickness of the coating layer were controlled and increased. We herein functionalized PP with three-dimensionally surface-grafted poly(N-benzyl-4-vinylpyridinium bromide) (PBVP) by a simple and rapid method involving graft polymerization and benzylation and examined the influence of different factors on the antiviral effect of the resulting plastic by using a plaque assay. The thickness of the PBVP coating, surface roughness, and amount of QACs, which jointly determine biocidal activity, could be controlled by adjusting the duration and intensity of the ultraviolet irradiation used for grafting. The best-performing sample reduced the viral infection titer of an enveloped model virus (bacteriophage ϕ6) by approximately 5 orders of magnitude after 60 min of contact and retained its antiviral activity after surface polishing-simulated scratching and abrasion, which indicated the localization of QACs across the coating interior. Our method may expand the scope of application to resin plates as well as fibers of PP. Given that the developed approach is not limited to PP and may be applied to other low-surface-energy olefinic polymers such as polyethylene and polybutene, our work paves the way for the fabrication of a wide range of biocidal surfaces for use in diverse environments, helping to prevent viral infection.

3D modeling and printing of bacteriophage Φ29

3D modeling and printing of bacteriophage Φ29

Flexible structural arrangement and DNA-binding properties of protein p6 from Bacillus subtillis phage φ29.

The genome-organizing protein p6 of Bacillus subtilis bacteriophage φ29 plays an essential role in viral development by activating the initiation of DNA replication and participating in the early-to-late transcriptional switch. These activities require the formation of a nucleoprotein complex in which the DNA adopts a right-handed superhelix wrapping around a multimeric p6 scaffold, restraining positive supercoiling and compacting the viral genome. Due to the absence of homologous structures, prior attempts to unveil p6's structural architecture failed. Here, we employed AlphaFold2 to engineer rational p6 constructs yielding crystals for three-dimensional structure determination. Our findings reveal a novel fold adopted by p6 that sheds light on its self-association mechanism and its interaction with DNA. By means of protein-DNA docking and molecular dynamic simulations, we have generated a comprehensive structural model for the nucleoprotein complex that consistently aligns with its established biochemical and thermodynamic parameters. Besides, through analytical ultracentrifugation, we have confirmed the hydrodynamic properties of the nucleocomplex, further validating in solution our proposed model. Importantly, the disclosed structure not only provides a highly accurate explanation for previously experimental data accumulated over decades, but also enhances our holistic understanding of the structural and functional attributes of protein p6 during φ29 infection.

In Vivo Production of dsRNA Using Bacteriophage ϕ6 in Pseudomonas syringae Cit7 Cells.

RNA interference (RNAi), also known as post-transcriptional gene silencing (PTGS), is one of the emerging genetic engineering techniques to effectively silence or inhibit the expression of target genes. This chapter describes a method for in vivo production of dsRNA in non-pathogenic Pseudomonas syringae strains using phage ϕ6 RNA-dependent RNA polymerase, extraction and purification of dsRNA from bacterial solution, and the use of dsRNA to induce silencing of green fluorescent protein (GFP) in transgenic Nicotiana benthamiana.

Degradation of 2-naphthol in water and antibacterial/antiviral activity by Zn2SnO4, ZnSn(OH)6 and Y2Sn2O7

White single-phase powders of Zn2SnO4, ZnSn(OH)6 and Y2Sn2O7 were prepared using hydrothermal method. In the 2-naphthol aqueous solutions in which these powders were immersed, ZnSn(OH)6 and Y2Sn2O7 reduced the 2-naphthol concentration in the dark. The concentration-decreasing rate temperature dependence, the activation energy, and the binding energy change suggested that the oxidative decomposition of 2-naphthol resulted from the Mars – van Krevelen (MvK) mechanism of Sn. Near non-occurrence of ion elution in water was confirmed for these materials, except for Zn in Zn2SnO4. Among these samples, Y2Sn2O7 exhibited the highest antibacterial and antiviral activities against Escherichia coli, Staphylococcus aureus, bacteriophage Qβ, and bacteriophage Φ6 in the dark. Adsorption attributable to electrostatic interactions between cationic samples and bacteria/viruses and the MvK mechanism were expected to lead to protein denaturation and consequently to antibacterial activity and antiviral activity. For Y2Sn2O7, the specific interaction between Y and phosphate ions possibly improved their antibacterial and antiviral activities. This white, non-eluting material was found to have degrees of high antibacterial and antiviral activity.

Structural Studies of Bacteriophage Φ6 and Its Transformations during Its Life Cycle.

From the first isolation of the cystovirus bacteriophage Φ6 from Pseudomonas syringae 50 years ago, we have progressed to a better understanding of the structure and transformations of many parts of the virion. The three-layered virion, encapsulating the tripartite double-stranded RNA (dsRNA) genome, breaches the cell envelope upon infection, generates its own transcripts, and coopts the bacterial machinery to produce its proteins. The generation of a new virion starts with a procapsid with a contracted shape, followed by the packaging of single-stranded RNA segments with concurrent expansion of the capsid, and finally replication to reconstitute the dsRNA genome. The outer two layers are then added, and the fully formed virion released by cell lysis. Most of the procapsid structure, composed of the proteins P1, P2, P4, and P7 is now known, as well as its transformations to the mature, packaged nucleocapsid. The outer two layers are less well-studied. One additional study investigated the binding of the host protein YajQ to the infecting nucleocapsid, where it enhances the transcription of the large RNA segment that codes for the capsid proteins. Finally, I relate the structural aspects of bacteriophage Φ6 to those of other dsRNA viruses, noting the similarities and differences.

A Comparative Analysis of VirLock and Bacteriophage ϕ6 through the Lens of Game Theory

The novelty of this paper lies in its perspective, which underscores the fruitful correlation between biological and computer viruses. In the realm of computer science, the study of theoretical concepts often intersects with practical applications. Computer viruses have many common traits with their biological counterparts. Studying their correlation may enhance our perspective and, ultimately, augment our ability to successfully protect our computer systems and data against viruses. Game theory may be an appropriate tool for establishing the link between biological and computer viruses. In this work, we establish correlations between a well-known computer virus, VirLock, with an equally well-studied biological virus, the bacteriophage ϕ6. VirLock is a formidable ransomware that encrypts user files and demands a ransom for data restoration. Drawing a parallel with the biological virus bacteriophage ϕ6, we uncover conceptual links like shared attributes and behaviors, as well as useful insights. Following this line of thought, we suggest efficient strategies based on a game theory perspective, which have the potential to address the infections caused by VirLock, and other viruses with analogous behavior. Moreover, we propose mathematical formulations that integrate real-world variables, providing a means to gauge virus severity and design robust defensive strategies and analytics. This interdisciplinary inquiry, fusing game theory, biology, and computer science, advances our understanding of virus behavior, paving the way for the development of effective countermeasures while presenting an alternative viewpoint. Throughout this theoretical exploration, we contribute to the ongoing discourse on computer virus behavior and stimulate new avenues for addressing digital threats. In particular, the formulas and framework developed in this work can facilitate better risk analysis and assessment, and become useful tools in penetration testing analysis, helping companies and organizations enhance their security.

Focusing properties of Azimuthally Polarized Lorentz Gauss Vortex Beam through a Dielectric Interface

Tight focusing properties of azimuthally polarized Lorentz Gaussian vortex beam through a dielectric interface are numerically studied by vector diffraction theory. The focusing properties, such as spot size, depth of focus, and maximum intensity position, are numerically calculated by properly manipulating the Lorentz parameter with/without annular obstruction values. Thus, using annular obstruction, one can generate a highly confined focal spot of long focal depth when using an azimuthally polarized Lorentz Gaussian vortex beam. Full Text: PDF References A. Ashkin et al., "Observation of a single-beam gradient force optical trap for dielectric particles", Opt. Lett. 11, 288 (1986). CrossRef A. Ambardekar, Y.Q. Li, "Optical levitation and manipulation of stuck particles with pulsed optical tweezers", Opt. Lett. 30, 1797 (2005). CrossRef P. Zemánek, C.J. Foot, "Atomic dipole trap formed by blue detuned strong Gaussian standing wave", Opt. Commun. 146, 119(1998). CrossRef S.M. Block et al., "Bead movement by single kinesin molecules studied with optical tweezers", Nature 348, 348 (1990). CrossRef D.E. Smithet al., "The bacteriophage φ29 portal motor can package DNA against a large internal force", Nature 413, 748 (2001). CrossRef L. Oroszi et al., "Direct Measurement of Torque in an Optical Trap and Its Application to Double-Strand DNA", Phys. Rev. Lett. 97, 058301 (2006). CrossRef D.P. Biss, T.G. Brown, "Cylindrical vector beam focusing through a dielectric interface", Opt. Express 9, 490 (2001). CrossRef P. Török et al., "Electromagnetic diffraction of light focused through a planar interface between materials of mismatched refractive indices: structure of the electromagnetic field. I", J. Opt. Soc. Am. A 12, 2136 (1995). CrossRef S.H. Wiersma et al., "Comparison of different theories for focusing through a plane interface", J. Opt. Soc. Am. A 14, 1482 (1997). CrossRef L.E. Helseth, "Roles of polarization, phase and amplitude in solid immersion lens systems", Opt. Commun. 191, 161 (2001). CrossRef P. Zhou et al., "Propagation properties of a Lorentz beam array", Appl. Opt. 49, 2497 (2010). CrossRef O.E. Gawhary, S. Severini, "Lorentz beams and symmetry properties in paraxial optics", J. Opt. A: Pure Appl Opt 8, 409 (2006). CrossRef J. Yang et al., "Focusing of diode laser beams: a partially coherent Lorentz model", Proc. SPIE 6824, 68240 A (2007). CrossRef O.E. Gawhary, S. Severini, "Lorentz beams as a basis for a new class of rectangularly symmetric optical fields", Opt. Commun. 269, 274 (2007). CrossRef H. Yu, L. Xiong, B. Lü, "Nonparaxial Lorentz and Lorentz–Gauss beams", Optik 121,1455(2010). CrossRef Z. Zhang, J. Pu, X. Wang, "Tight Focusing of Radially and Azimuthally Polarized Vortex Beams through a Dielectric Interface", Chin. Phys. Lett. 25, 1664 (2008). CrossRef

Photodynamic inactivation of a RNA-virus model using water-soluble β-octa-Substituted pyridinium-pyrazolyl phthalocyanines

Among the various groups of microorganisms, viruses have generally a greater capacity for mutation, especially RNA viruses, as was demonstrated by SARS-CoV2 virus mutations. This high mutation rate promotes the development of their resistance to traditional antivirals and establishes the resistance behaviour in virus populations, decreasing their susceptibility to these drugs. In this context, the photodynamic treatment appears as a potentially effective method against microorganisms and, considering its mode of action is not likely to lead to the development of resistance. In this work, two newly zinc(II) phthalocyanines (ZnPcs) bearing pyridinium-pyrazolyl groups (2a and 3a) were synthesized, characterized, and applied in photodynamic inactivation (PDI) of bacteriophage Φ6 (or Phage Phi6) as a RNA-virus model. These quaternized dyes were applied at different concentrations (from 5.0 to 20 μM, and under white light irradiation in the irradiance range between 50 and 150 mW/cm2) to test their efficiency for possible clinical or environmental applications. The results showed that the new cationic ZnPcs 2a and 3a efficiently inactivate the RNA-virus model (bacteriophage Φ6), even at the lowest tested irradiance. These compounds are thus promising photosensitizers to be used in various contexts.

Discovery and Classification of the φ6 Bacteriophage: An Historical Review.

The year 2023 marks the fiftieth anniversary of the discovery of the bacteriophage φ6. The review provides a look back on the initial discovery and classification of the lipid-containing and segmented double-stranded RNA (dsRNA) genome-containing bacteriophage-the first identified cystovirus. The historical discussion describes, for the most part, the first 10 years of the research employing contemporary mutation techniques, biochemical, and structural analysis to describe the basic outline of the virus replication mechanisms and structure. The physical nature of φ6 was initially controversial as it was the first bacteriophage found that contained segmented dsRNA, resulting in a series of early publications that defined the unusual genomic quality. The technology and methods utilized in the initial research (crude by current standards) meant that the first studies were quite time-consuming, hence the lengthy period covered by this review. Yet when the data were accepted, the relationship to the reoviruses was apparent, launching great interest in cystoviruses, research that continues to this day.