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The propagation of antibiotic-resistant bacteria (ARB) and antibiotic resistance genes (ARGs) induced by the release of antibiotics poses great threats to ecological safety and human health. In this study, periodate (PI)/FeS 2 /simulated sunlight (SSL) system was employed to remove representative ARB, ARGs and antibiotics in water. 1 × 10 7 CFU mL -1 of gentamycin-resistant Escherichia coli was effectively disinfected below limit of detection in PI/FeS 2 /SSL system under different water matrix and in real water samples. Sulfadiazine-resistant Pseudomonas and Gram-positive Bacillus subtilis could also be efficiently sterilized. Theoretical calculation showed that (110) facet was the most reactive facet on FeS 2 to activate PI for the generation of reactive species (·OH, ·O 2 - , h + and Fe(IV)=O) to damage cell membrane and intracellular enzyme defense system. Both intracellular and extracellular ARGs could be degraded and the expression levels of multidrug resistance-related genes were downregulated during the disinfection process. Thus, horizontal gene transfer (HGT) of ARB was inhibited. Moreover, PI/FeS 2 /SSL system could disinfect ARB in a continuous flow reactor and in an enlarged reactor under natural sunlight irradiation. PI/FeS 2 /SSL system could also effectively degrade the HGT-promoting antibiotic (ciprofloxacin) via hydroxylation and ring cleavage process. Overall, PI/FeS 2 /SSL exhibited great promise for the elimination of antibiotic resistance from water., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier B.V. All rights reserved.)

Background: Goat milk is considered a nutritionally superior resource, owing to its advantageous nutritional attributes. Nevertheless, it is susceptible to spoilage and the persistence of pathogens. Electron beam irradiation stands as a promising non-thermal processing technique capable of prolonging shelf life with minimal residue and a high degree of automation., Results: The effects of electron beam irradiation (2, 3, 5, and 7 kGy) on microorganisms, physicochemical properties, and protein structure of goat milk compared with conventional pasteurized goat milk (PGM) was evaluated. It was found that a 2 kGy electron beam irradiation reduces the total microbial count of goat milk by 6-logs, and the irradiated goat milk protein secondary structure showed a significant decrease in ɑ-helix content. Low irradiation doses led to microaggregation and crosslinking. In contrast, high doses (≥ 5 kGy) slightly disrupted the aggregates and decreased the particle size, disrupting the microscopic surface structure of goat milk, verified by scanning electron microscopy and confocal laser scanning microscopy., Conclusion: The irradiation of goat milk with a 2 kGy electron beam may effectively inactivate harmful microorganisms in the milk and maintain/or improve the physicochemical quality and protein structure of goat milk compared to thermal pasteurization. © 2024 Society of Chemical Industry., (© 2024 Society of Chemical Industry.)

Background: The search for factors beyond the radiotherapy dose that could identify patients more at risk of developing radio-induced toxicity is essential to establish personalised treatment protocols for improving the quality-of-life of survivors. To investigate the role of the intestinal microbiota in the development of radiotherapy-induced gastrointestinal toxicity, the MicroLearner observational cohort study characterised the intestinal microbiota of 136 (discovery) and 79 (validation) consecutive prostate cancer patients at baseline radiotherapy., Methods: Gastrointestinal toxicity was assessed weekly during RT using CTCAE. An average grade >1.3 over time points was used to identify patients suffering from persistent acute toxicity (endpoint). The microbiota of patients was quantified from the baseline faecal samples using 16S rRNA gene sequencing technology and the Ion Reporter metagenomic pipeline. Statistical techniques and computational and machine learning tools were used to extract, functionally characterise, and predict core features of the bacterial communities of patients who developed acute gastrointestinal toxicity., Findings: Analysis of the core bacterial composition in the discovery cohort revealed a cluster of patients significantly enriched for toxicity, displaying a toxicity rate of 60%. Based on selected high-risk microbiota compositional features, we developed a clinical decision tree that could effectively predict the risk of toxicity based on the relative abundance of genera Faecalibacterium, Bacteroides, Parabacteroides, Alistipes, Prevotella and Phascolarctobacterium both in internal and external validation cohorts., Interpretation: We provide evidence showing that intestinal bacteria profiling from baseline faecal samples can be effectively used in the clinic to improve the pre-radiotherapy assessment of gastrointestinal toxicity risk in prostate cancer patients., Funding: Italian Ministry of Health (Promotion of Institutional Research INT-year 2016, 5 × 1000, Ricerca Corrente funds). Fondazione Regionale per la Ricerca Biomedica (ID 2721017). AIRC (IG 21479)., Competing Interests: Declaration of interests The authors declare no conflict of interest., (Copyright © 2024 The Author(s). Published by Elsevier B.V. All rights reserved.)

Currently, microbial contamination issues have globally brought out a huge health threat to human beings and animals. To be specific, microorganisms including bacteria and viruses display durable ecological toxicity and various diseases to aquatic organisms. In the past decade, the photocatalytic microorganism inactivation technique has attracted more and more concern owing to its green, low-cost, and sustainable process. A variety kinds of photocatalysts have been employed for killing microorganisms in the natural environment. However, two predominant shortcomings including low activity of photocatalysts and diverse impacts of water characteristics are still displayed in the current photocatalytic disinfection system. So far, various strategies to improve the inherent activity of photocatalysts. Other than the modification of photocatalysts, the optimization of environments of water bodies has been also conducted to enhance microorganisms inactivation. In this mini-review, we outlined the recent progress in photocatalytic sterilization of microorganisms. Meanwhile, the relevant methods of photocatalyst modification and the influences of water body characteristics on disinfection ability were thoroughly elaborated. More importantly, the relationships between strategies for constructing advanced photocatalytic microorganism inactivation systems and improved performance were correlated. Finally, the perspectives on the prospects and challenges of photocatalytic disinfection were presented. We sincerely hope that this critical mini-review can inspire some new concepts and ideas in designing advanced photocatalytic disinfection systems., Competing Interests: Declaration of competing interest The authors state that they have no known competing economic interests or personal relationships that could affect the work reported in this paper., (Copyright © 2024 Elsevier Ltd. All rights reserved.)

The district of Perus, located in the city of São Paulo, Brazil, is renowned for its weathered granitic-pegmatitic masses, which harbor a significant number of uraniferous minerals that contribute to ionizing radiation levels up to 20 times higher than the background levels. In this study, aseptically collected mineral samples from the area were utilized to isolate 15 microorganisms, which were subjected to pre-screening tests involving UV-C and UV-B radiation. The microorganisms that exhibited the highest resistance to ultraviolet (UV) radiation were selected for the construction of survival curves for UV-C, broad-band UV-B, and solar simulation resistance testing. Subsequently, the four strains that demonstrated superior survival capabilities under UV radiation exposure were chosen for 16S rRNA gene sequencing. Among these, Nocardioides sp. O4R and Nocardioides sp. MA2R demonstrated the most promising outcomes in the UV radiation resistance assessments, showcasing comparable performance to the well-established radioresistant model organism Deinococcus radiodurans . These findings underscore the potential of naturally occurring high-radiation environments as valuable resources for the investigation of UV-resistant microorganisms. Astrobiology 24, 783-794.

Background: The standard of care for disinfecting needleless connectors (NCs) of central venous catheters includes alcohol-containing caps or up to a 15-second scrub with alcohol or chlorhexidine. Due to the clinical impact and high cost of treating Central line-associated bloodstream infections (CLABSI), reducing the incidence of CLABSI is a priority for public health and of the Centers for Disease Control. Alcohol-containing caps have been demonstrated to disinfect external NC surfaces, but not the internal surface. Ultraviolet light (UV-C) is a strategy for disinfection of NC internal and external surfaces., Methods: Four clinically relevant bacteria (Staphylococcus aureus, Staphylococcus epidermidis, Escherichia coli, Pseudomonas aeruginosa) and Candida albicans were inoculated on NCs. Disinfection efficacy was measured after exposure to one second of 285 nm UV-C light at 48 mW/cm 2 in a proprietary handheld device and UV-C transparent NC or standard of care. Disinfection of internal and external surfaces of NC inoculated with S aureus using alcohol caps, and UV-C was also compared., Results: A 4-log reduction in colony forming units (CFUs) on the interior and exterior surfaces of the UV-transparent NC of clinically relevant pathogens was observed with UV-C light at this power for 1 second., Discussion: We demonstrated the efficacy of UV-C for the disinfection of NCs in one second using the UV-C device in benchtop studies., Conclusions: This device holds promise for reducing CLABSI, and clinical studies are planned., (Published by Elsevier Inc.)

Sterilization is commonly used to remove or reduce the biotic constraints of a soil to allow recolonization by soil-dwelling organisms, with autoclaving and gamma irradiation being the most frequently used approaches. Many studies have characterized sterilization impacts on soil physicochemical properties, with gamma irradiation often described as the preferred approach, despite the lower cost and higher scalability of autoclaving. However, few studies have compared how sterilization techniques impact soil recolonization by microorganisms. Here, we compared how two sterilization approaches (autoclaving; gamma irradiation) and soil washing impacted microbial recolonization of soil from a diverse soil inoculum. Sterilization method had little impact on microbial alpha diversity across recolonized soils. For sterile soil regrowth microcosms, species richness and diversity were significantly reduced by autoclaving relative to gamma irradiation, particularly for fungi. There was no impact of sterilization method on bacterial composition in recolonized soils and minimal impact on fungal composition ( P = 0.05). Washing soils had a greater impact on microbial composition than sterilization method, and sterile soil regrowth had negligible impacts on microbial recolonization. These data suggest that sterilization method has no clear impact on microbial recolonization, at least across the soils tested, indicating that soil autoclaving is an appropriate and economical approach for biotically clearing soils.IMPORTANCESterilized soils represent soil-like environments that act as a medium to study microbial colonization dynamics in more "natural" settings relative to artificial culturing environments. Soil sterilization is often carried out by gamma irradiation or autoclaving, which both alter soil properties, but gamma irradiation is thought to be the gentler technique. Gamma irradiation can be cost prohibitive and does not scale well for larger experiments. We sought to examine how soil sterilization technique can impact microbial colonization, and additionally looked at the impact of soil washing which is believed to remove soil toxins that inhibit soil recolonization. We found that both gamma-irradiated and autoclaved soils showed similar colonization patterns when reintroducing microorganisms. Soil washing, relative to sterilization technique, had a greater impact on which microorganisms were able to recolonize the soil. When allowing sterilized soils to regrow (i.e., persisting microorganisms), gamma irradiation performed worse, suggesting that gamma irradiation does not biotically clear soils as well as autoclaving. These data suggest that both sterilization techniques are comparable, and that autoclaving may be more effective at biotically clearing soil., Competing Interests: The authors declare no conflict of interest.

Bentonite is an integral part of the engineered barrier system (EBS) in deep geological repositories (DGR) for nuclear waste, but its indigenous microorganisms may jeopardize long-term EBS integrity. To predict microbial activity in DGRs, it is essential to understand microbial reactions to the early hot phase of DGR evolution. Two bentonites (BCV and MX-80) with varied bentonite/water ratios and saturation levels (compacted to 1600 kg.m - 3 dry density/powder/suspension), were subjected to heat (90-150 °C) and irradiation (0.4 Gy.h - 1 ) in the long-term experiments (up to 18 months). Molecular-genetic, microscopic, and cultivation-based techniques assessed microbial survivability. Exposure to 90 °C and 150 °C notably diminished microbial viability, irrespective of bentonite form, with negligible impacts from irradiation or sample type compared to temperature. Bentonite powder samples exhibited microbial recovery after 90 °C heating for up to 6 months but not 12 months in most cases; exposure to 150 °C had an even stronger effect. Further long-term experiments at additional temperatures combined with the mathematical prediction of temperature evolution in DGR are recommended to validate the possible evolution and spatial distribution of microbially depleted zones in bentonite buffer around the waste canisters and refine predictions of microbial effects over time in the DGR., (© 2024. The Author(s).)

The aim of the present study is to develop a pH-sensing biopolymer film based on the immobilization of red cabbage extract (RCE) within bacterial cellulose (BC) to detect contamination and gamma radiation exposure in cucumbers. The results obtained show a sensitivity to pH changes for RCE in its aqueous form and that incorporated within BC films (RCE-BC), both showed color change correlated to bacterial growth (R 2  = 0.91), this was supported with increase in pH values from 2 to 12 (R 2  = 0.98). RCE and RCE-BC exposure to gamma radiation (0, 2.5, 5, 10, 15, 20, 25 kGy) resulted in gradual decrease in color that was more evident in RCE aqueous samples. To sense bacterial contamination of cucumbers, the total count was followed at 0, 5, 10 and 15 days in cold storage conditions and was found to reach 9.13 and 5.47 log cfu/mL for non-irradiated and 2 kGy irradiated samples, respectively. The main isolates detected throughout this storage period were identified as Pseudomonas fluorescens, Erwinia sp. Pantoea agglomerans using matrix assisted laser desorption ionization-time of flight-ms (MALDI-TOF-MS). Bacterial growth in stored irradiated cucumbers was detected by color change within 5 and 10 days of storage, after which there was no evident change. This is very useful since contamination within the early days of storage cannot be sensed with the naked eye. This study is the first to highlight utilizing RCE and RCE-BC as eco-friendly pH-sensing indicator films for intelligent food packaging to detect both food contamination and gamma preservation for refrigerator stored cucumbers., (© 2024. The Author(s).)

Introduction and Objective: Ultraviolet light in the UV-C band is known as germicidal radiation and was widely used for both sterilization of the equipment and creation of a sterile environment. The aim of the study is to assess the effectiveness of inactivation of microorganisms deposited on surfaces with various textures by UV-C radiation disinfection devices., Material and Methods: Five microorganisms (3 bacteria, virus, and fungus) deposited on metal, plastic, and glass surfaces with smooth and rough textures were irradiated with UV-C light emitted by low-pressure mercury lamp and ultraviolet emitting diodes (LEDs), from a distance of 0.5 m, 1 m, and 1.5 m to check their survivability after 20-minute exposure., Results and Conclusions: Both tested UV-C sources were effective in inactivation of microorganisms; however, LED emitter was more efficient in this respect than the mercury lamp. The survival rate of microorganisms depended on the UV-C dose, conditioned by the distance from UV-C source being the highest at 0.5 m and the lowest at 1.5 m. For the tested microorganisms, the highest survival rate after UV-C irradiation was usually visible on glass and plastic surfaces. This observation should be considered in all environments where the type of material (from which the elements of technical equipment are manufactured and may be contaminated by specific activities) is important for maintaining the proper level of hygiene and avoiding the unwanted and uncontrolled spread of microbiological pollution.

In recent years, some microorganisms have shown resistance to conventional treatments. Considering this increase in resistant pathogens, treatment alternatives are needed to promote greater treatment efficiency. In this sense, antimicrobial photodynamic therapy (aPDT) has been an alternative treatment. This technique uses a photosensitizer that is activated by light with a specific wavelength producing reactive species, leading to the death of pathogenic microorganisms. In this study, bacteriochlorophyll derivatives such as bacteriochlorin metoxi (Bchl-M) and bacteriochlorin trizma (Bchl-T) obtained from purple bacterium (Rhodopseudomonas faecalis), were evaluated as photosensitizers in the aPDT. Photodynamic inactivation (PDI) of the microorganisms Staphylococcus aureus, Micrococcus luteus, Candida albicans and Pseudomonas aeruginosa was investigated with both bacteriochlorins (Bchl-M and Bchl-T) at different concentrations (1, 15 and 30 µM for S. aureus; 1, 15, 30, 45, 60 and 75 µM for M. luteus; 30, 60, 90, 105, 120 and 150 µM for C. albicans; and 200 µM for P. aeruginosa) and different doses of light (20 and 30 J/cm 2 for S. aureus and M. luteus; 30 and 45 J/cm 2 for C. albicans; and 45 J/cm 2 for P. aeruginosa) to inactivate them. Both photosensitizers showed good activation against S. aureus and for M. luteus, we observed the inactivation of these microorganisms at approximately 3 log, showing to be a good photosensitizers for these microorganisms., (© 2024. The Author(s) under exclusive licence to Sociedade Brasileira de Microbiologia.)

Holder pasteurization (HoP) enhances donor human milk microbiological safety but damages many bioactive milk proteins. Though ultraviolet-C irradiation (UV-C) can enhance safety while better preserving some milk proteins, it has not been optimized for dose or effect on a larger array of bioactive proteins. We determined the minimal UV-C parameters that provide >5-log reductions of relevant bacteria in human milk and how these treatments affect an array of bioactive proteins, vitamin E, and lipid oxidation. Treatment at 6000 and 12 000 J/L of UV-C resulted in >5-log reductions of all vegetative bacteria and bacterial spores, respectively. Both dosages improved retention of immunoglobulin A (IgA), IgG, IgM, lactoferrin, cathepsin D, and elastase and activities of bile-salt-stimulated lipase and lysozyme compared with HoP. These UV-C doses caused minor reductions in α-tocopherol but not γ-tocopherol and no increases in lipid oxidation products. UV-C treatment is a promising approach for donor human milk processing.

Due to its increased safety over ultraviolet light, there is interest in the development of antimicrobial violet-blue light technologies for infection control applications. To ensure compatibility with exposed materials and tissue, the light irradiances and dose regimes used must be suitable for the target application. This study investigates the antimicrobial dose responses and germicidal efficiency of 405 nm violet-blue light when applied at a range of irradiance levels, for inactivation of surface-seeded and suspended bacteria. Bacteria were seeded onto agar surfaces (10 1 -10 8 CFUplate -1 ) or suspended in PBS (10 3 -10 9 CFUmL -1 ) and exposed to increasing doses of 405-nm light (≤ 288 Jcm -2 ) using various irradiances (0.5-150 mWcm -2 ), with susceptibility at equivalent light doses compared. Bacterial reductions ≥ 96% were demonstrated in all cases for lower irradiance (≤ 5 mWcm -2 ) exposures. Comparisons indicated, on a per unit dose basis, that significantly lower doses were required for significant reductions of all species when exposed at lower irradiances: 3-30 Jcm -2 /0.5 mWcm -2  compared to 9-75 Jcm -2 /50 mWcm -2  for low cell density (10 2  CFUplate -1 ) surface exposures and 22.5 Jcm -2 /5 mWcm -2  compared to 67.5 Jcm -2 /150 mWcm -2  for low density (10 3  CFUmL -1 ) liquid exposures (P ≤ 0.05). Similar patterns were observed at higher densities, excluding S. aureus exposed at 10 9  CFUmL -1 , suggesting bacterial density at predictable levels has minimal influence on decontamination efficacy. This study provides fundamental evidence of the greater energy efficacy of 405-nm light for inactivation of clinically-significant pathogens when lower irradiances are employed, further supporting its relevance for practical decontamination applications., (© 2024. The Author(s).)

UV/peracetic acid (PAA) treatment presents a promising approach for antibiotic removal, but its effects on microbial community and proliferation of antibiotic resistance genes (ARGs) during the subsequent bio-treatment remain unclear. Thus, we evaluated the effects of the UV/PAA on tetracycline (TTC) degradation, followed by introduction of the treated wastewater into the bio-treatment system to monitor changes in ARG expression and biodegradability. Results demonstrated effective TTC elimination by the UV/PAA system, with carbon-centered radicals playing a significant role. Crucially, the UV/PAA system not only eliminated antibacterial activity but also inhibited potential ARG host growth, thereby minimizing the emergence and dissemination of ARGs during subsequent bio-treatment. Additionally, the UV/PAA system efficiently removed multi-antibiotic resistant bacteria and ARGs from the bio-treatment effluent, preventing ARGs from being released into the environment. Hence, we propose a multi-barrier strategy for treating antibiotic-containing wastewater, integrating UV/PAA pre-treatment and post-disinfection with bio-treatment. The inhibition of ARGs transmission by the integrated system was verified through actual soil testing, confirming its effectiveness in preventing ARGs dissemination in the surrounding natural ecosystem. Overall, the UV/PAA treatment system offers a promising solution for tackling ARGs challenges by controlling ARGs proliferation at the source and minimizing their release at the end of the treatment process., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier B.V. All rights reserved.)

Sandy sediments of lowland streams are transported as migrating ripples. Benthic microorganisms colonizing sandy grains are exposed to frequent moving-resting cycles and are believed to be shaped by two dominant environmental factors: mechanical stress during the moving phase causing biofilm abrasion, and alternating light-dark cycles during the resting phase. Our study consisted of two laboratory experiments and aimed to decipher which environmental factor causes the previously observed hampered sediment-associated microbial activity and altered community structure during ripple migration. The first experiment tested the effect of three different migration velocities under comparable light conditions. The second experiment compared migrating and stationary sediments under either constant light exposure or light oscillation. We hypothesized that microbial activity and community structure would be more strongly affected by (1) higher compared to lower migration velocities, and by (2) light oscillation compared to mechanical stress. Combining the results from both experiments, we observed lower microbial activity and an altered community structure in sediments exposed to light oscillation, whereas migration velocity had less impact on community activity and structure. Our findings indicate that light oscillation is the predominating environmental factor acting during ripple migration, resulting in an increased vulnerability of light-dependent photoautotrophs and a possible shift toward heterotrophy., (© The Author(s) 2024. Published by Oxford University Press on behalf of FEMS.)

Introduction: Healthcare-acquired infections and overuse of antibiotics are a common problem. Rising emergence of antibiotic and antiseptic resistances requires new methods of microbial decontamination or decolonization as the use of far-UV-C radiation., Methods: The microbicidal efficacy of UV-C radiation (222 nm, 233 nm, 254 nm) was determined in a quantitative carrier test and on 3D-epidermis models against Staphylococcus (S.) aureus, S.epidermidis, S.haemolyticus, S.lugdunensis, Klebsiella pneumoniae, and Pseudomonas aeruginosa. To mimic realistic conditions, sodium chloride solution, mucin, albumin, artificial saliva, artificial wound exudate and artificial sweat were used., Results: In sodium chloride solution, irradiation with a dose of 40 mJ/cm 2 (233 nm) was sufficient to achieve 5 lg reduction independent of bacteria genus or species. In artificial sweat, albumin and artificial wound exudate, a reduction >3 lg was reached for most of the bacteria. Mucin and artificial saliva decreased the reduction to <2 lg. On 3D epidermis models, reduction was lower than in the carrier test., Conclusion: UV-C radiation at 233 nm was proven to be efficient in bacteria inactivation independent of genus or species thus being a promising candidate for clinical use in the presence of humans and on skin/mucosa., Competing Interests: Declaration of competing interest None., (Copyright © 2024 The Author(s). Published by Elsevier Masson SAS.. All rights reserved.)

Radiation therapy for abdominopelvic malignancies often results in damage to the gastrointestinal tract (GIT) and permanent changes in bowel function. An overlooked component of the pathophysiology of radiation-induced bowel injury is the role of the gut microbiome. The goal of this research was to identify the impacts of acute radiation exposure on the GIT and gut microbiome. C57BL/6 mice exposed to whole-body X-rays (0.1-3 Gy) were assessed for histological and microbiome changes 48 h post-radiation exposure. Within the ileum, a dose of 3 Gy significantly decreased crypt depth as well as the number of goblet cells, but increased overall goblet cell size. Overall, radiation altered the microbial distribution within each of the main phyla in a dose- and tissue-dependent manner. Within the Firmicutes phylum, high dose irradiation resulted in significant alterations in bacteria from the class Bacilli within the small bowels, and from the class Clostridia in the large bowels. The 3 Gy radiation also significantly increased the abundance of bacterial families from the Bacteroidetes phylum in the colon and feces. Overall, we identified various alterations in microbiome composition following acute radiation exposure, which could potentially lead to novel biomarkers for tracking patient toxicities or could be used as targets for mitigation strategies against radiation damage.

The development of alternative techniques to efficiently inactivate bacterial suspensions is crucial to prevent transmission of waterborne illness, particularly when commonly used techniques such as heating, filtration, chlorination, or ultraviolet treatment are not practical or feasible. We examine the effect of MHz-order acoustic wave irradiation in the form of surface acoustic waves (SAWs) on Gram-positive (Escherichia coli) and Gram-negative (Brevibacillus borstelensis and Staphylococcus aureus) bacteria suspended in water droplets. A significant increase in the relative bacterial load reduction of colony-forming units (up to 74%) can be achieved by either increasing (1) the excitation power, or, (2) the acoustic treatment duration, which we attributed to the effect of the acoustic radiation force exerted on the bacteria. Consequently, by increasing the maximum pressure amplitude via a hybrid modulation scheme involving a combination of amplitude and pulse-width modulation, we observe that the bacterial inactivation efficiency can be further increased by approximately 14%. By combining this scalable acoustic-based bacterial inactivation platform with plasma-activated water, a 100% reduction in E. coli is observed in less than 10 mins, therefore demonstrating the potential of the synergistic effects of MHz-order acoustic irradiation and plasma-activated water as an efficient strategy for water decontamination., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023 The Author(s). Published by Elsevier B.V. All rights reserved.)

Ultraviolet light (UV) acts as a powerful disinfectant and can prevent contamination of personal hygiene from various contaminated environments. The 222-nm wavelength of UV-C has a highly effective sterilization activity and is safer than 275-nm UV-C. We investigated the irradiation efficacy of 222-nm UV-C against contaminating bacteria and viruses in liquid and fabric environments. We conducted colony-forming unit assays to determine the number of viable cells and a 50% tissue culture infectious dose assay to evaluate the virus titration. A minimum dose of 27 mJ/cm2 of 222-nm UV-C was required for >95% germicidal activity for gram-negative and -positive bacteria. A 25.1 mJ/cm2 dose could ensure >95% virucidal activity against low-pathogenic avian influenza virus and severe acute respiratory syndrome coronavirus (SARS-CoV-2). In addition, this energy dose of 222-nm UV-C effectively inactivated SARS-CoV-2 variants, Delta and Omicron. These results provide valuable information on the disinfection efficiency of 222-nm UV-C in bacterial and virus-contaminated environments and can also develop into a powerful tool for individual hygiene., Competing Interests: The authors have declared that no competing interests exist., (Copyright: © 2023 Song et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.)

Germicidal ultraviolet (UV) devices have been widely used for pathogen disinfection in water, air, and on food and surfaces. Emerging UV technologies, like the krypton chloride (KrCl*) excimer emitting at 222 nm, are rapidly gaining popularity due to their minimal adverse effects on skin and eyes compared with conventional UV lamps emitting at 254 nm, opening opportunities for UV disinfection in occupied public spaces. In this study, inactivation of seven bacteria and five viruses, including waterborne, foodborne and respiratory pathogens, was determined in a thin-film aqueous solution using a filtered KrCl* excimer emitting primarily at 222 nm. Our results show that the KrCl* excimer can effectively inactivate all tested bacteria and viruses, with most microorganisms achieving more than 4-log (99.99%) reduction with a UV dose of 10 mJ cm -2 . Compared with conventional UV lamps, the KrCl* excimer lamp exhibited better disinfection performance for viruses but was slightly less effective for bacteria. The relationships between UV sensitivities at 222 and 254 nm for bacteria and viruses were evaluated using regression analysis, resulting in factors that could be used to estimate the KrCl* excimer disinfection performance from well-documented UV kinetics using conventional 254 nm UV lamps. This study provides fundamental information for pathogen disinfection when employing KrCl* excimers., (© 2022 American Society for Photobiology.)

Energy transfer from light-harvesting ketocarotenoids to the light-driven proton pump xanthorhodopsins has been previously demonstrated in two unique cases: an extreme halophilic bacterium 1 and a terrestrial cyanobacterium 2 . Attempts to find carotenoids that bind and transfer energy to abundant rhodopsin proton pumps 3 from marine photoheterotrophs have thus far failed 4-6 . Here we detected light energy transfer from the widespread hydroxylated carotenoids zeaxanthin and lutein to the retinal moiety of xanthorhodopsins and proteorhodopsins using functional metagenomics combined with chromophore extraction from the environment. The light-harvesting carotenoids transfer up to 42% of the harvested energy in the violet- or blue-light range to the green-light absorbing retinal chromophore. Our data suggest that these antennas may have a substantial effect on rhodopsin phototrophy in the world's lakes, seas and oceans. However, the functional implications of our findings are yet to be discovered., (© 2023. The Author(s), under exclusive licence to Springer Nature Limited.)

As an emerging UV source, ultraviolet light-emitting diodes (UV-LEDs) are increasingly being used for disinfection purposes. UVA-LEDs have a higher output power, lower cost, and stronger penetration and cause less harm than UVC-LEDs. In this study, a novel exposure mode based on UVA was proposed and well demonstrated by various experiments using S. aureus as an indicator. Compared with single-dose exposure, fractionated exposure with a 15 min interval between treatments resulted in increased S. aureus inactivation. A longer interval or lower first irradiation dose was unfavorable for inactivation. Fractionated exposure changed the inactivation rate constant and eliminated the shoulder in the fluence-response curves. This resulted in changing the sensitivity of bacteria to UVA and improving bacterial inactivation. Moreover, the fractioned exposure mode has universality for various bacteria (including gram-positive and gram-negative bacteria). S. aureus was not reactivated by photoreactivation or dark repair after UVA treatment. As expected, the cells were damaged more seriously after fractionated exposure, further suggesting the advantages of this new exposure mode. In addition, the mechanism by which bacteria were inactivated after fractionated exposure was investigated, and it was found that •OH played an important role. A longer interval between treatments showed an adverse effect on inactivation, mainly due to the reduction of •OH and recovery of intracellular GSH. In summary, the current work provides novel ideas for the application of UVA-LEDs, which will give more choices for disinfection treatment., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2022 The Authors. Published by Elsevier B.V. All rights reserved.)

Dining tables may present a risk to diners by transmitting bacteria and/or viruses. Currently, there is a lack of an environmental-friendly and convenient means to protect diners when they are sitting together. This investigation constructed far-UVC excimer lamps to disinfect dining-table surfaces. The lamps were mounted at different heights and orientations, and the irradiance on table surfaces was measured. The irradiation doses to obtain different inactivation efficiencies for Escherichia coli (E. coli) were provided. In addition, numerical modeling was conducted for irradiance and the resulting inactivation efficiency. The surface-to-surface (S2S) model was validated with the measured irradiance. The germicidal performance of far-UVC irradiation, the far-UVC doses to which diners were exposed, and the risk of exposure to the generated ozone were evaluated. The results revealed that an irradiation dose of 12.8 mJ/cm 2 can disinfect 99.9% of E. coli on surfaces. By varying the lamp irradiance output, the number and positions of the lamps, the far-UVC irradiation can achieve a 3-log reduction for a dining duration of 5 min. Besides, the far-UVC lamp has a low damage risk to diners when achieving an effective inactivation rate. Moreover, there is virtually no ozone exposure risk in a mechanically ventilated dining hall., (© 2023. The Author(s).)

Due to the changes in pathogenic species and the absence of research on topical skin antibiotics, the therapy of skin and soft tissue infections (SSTIs) is facing more and more severe challenges. It is particularly urgent to look for alternative therapies without induction of drug resistance. UV C (UVC) light within the range of 200 to 280 nm is one of the most common techniques used to kill and/or inactivate pathogenic microorganisms. However, the traditional most commonly used wavelength of 254 nm irradiated from a low-pressure mercury lamp is hazardous to human health, being both carcinogenic and damaging to eye tissues, which limits its applications in vivo . This research aimed to investigate the antimicrobial properties and influence of 275-nm UVC light from a light-emitting diode (UVC-LED light) on wound healing time. Five bacteria, three fungi, and scalded-mouse models combined with SSTIs were used to evaluate the antimicrobial effect in vitro and in vivo . 275-nm UVC-LED light inactivated both bacteria and fungi with a very short irradiation time in vitro and induced neither DNA damage nor epidermal lesions in the mice's skin. Furthermore, in mouse models of SSTIs induced by either methicillin-resistant Staphylococcus aureus (MRSA) or Candida albicans, the 275-nm UVC-LED light showed significant antimicrobial effects and shortened the wound healing time compared with that in the no-irradiation group. UVC-LED light at 275 nm has the potential to be a new form of physical therapy for SSTIs. IMPORTANCE As a common clinical problem, the therapy of SSTIs is facing growing challenges due to an increase in the number of drug-resistant bacteria and fungi. UV C (UVC) light sterilization has been widely used in all aspects of daily life, but there are very few reports about in vivo therapy using UVC light. It is well known that prolonged exposure to UVC light increases the possibility of skin cancer. In addition, it is also very harmful for eyes. UV irradiation with 254-nm UVC light can cause corneal damage, like thinning of the corneal epithelial layer, superficial punctate keratitis, corneal erosion, etc. In this study, we focused on looking for a more accessible light source and safer UVC wavelength, and 275-nm UVC LED light was chosen. We investigated its applicability for SSTIs therapy with relative skin safety and expected that it could be used as a new physical therapy method for SSTIs.

Recently, increasing attention has been paid to antibiotic resistance in stormwater runoff. However, there is no available literature about the control of antibiotic resistant bacteria (ARB) through 365 nm ultraviolet light-emitting diode (UVA/LED). In this study, batch experiments were conducted to investigate ARB inactivation kinetics, effects of light intensity and water matrix (including suspended solid (SS) concentration, initial pH and bacteria concentration), and potential transmission risks after UVA/LED irradiation. Results showed that ARB inactivation efficiencies reached 6.31 log reduction at 8 mW/cm 2 (86 J/cm 2 ) of UVA/LED for 180 min. ARB inactivation efficiencies increased with the increase of light intensity, and showed a linear relationship. ARB inactivation decreased with increasing SS levels, and the largest inactivation efficiencies was 3.56 log reduction at 50 mg/L of SS. Initial pH had slight effect on ARB inactivation through UVA/LED irradiation. A low initial bacteria concentration (10 5 CFU/mL) was not necessarily associated with good ARB inactivation (3.59 log reduction). After UVA/LED irradiation, ARB was hardly detected during 12 hr of dark repair, and the transfer frequency of kanamycin resistance gene was increased to 5.43 × 10 -4 . These suggested that the application of UVA/LED to inactivate ARB in stormwater runoff was feasible and desirable in this study.

The main objective of this study is to evaluate the effect of irradiation by Gamma rays and Electron Beam (E-Beam) on naturally occurring microorganisms shed in healthcare wastewater issued from multi-specialties hospital. We examined the susceptibility of naturally occurring total indicator bacteriophages towards Gamma rays and E-Beam irradiation to evaluate their appropriateness as viral indicators for healthcare wastewater quality control. Results showed that healthcare wastewater is a rich matrix containing bacteriophages surrogates of pathogenic waterborne viruses (4.5 Log 10 PFU/100 mL for SOMCPH and 2.3 Log 10 PFU/100 mL for FRNAPH), antibiotic resistant bacteria (Mean concentrations from 2.3 to 5.5 Log 10 CFU/100 mL), molds and yeasts (2.7 Log 10 CFU/100 mL), and spores of Clostridium perfringens (Mean concentration of 3.3 Log 10 CFU/100 mL). After E-Beam irradiation, naturally occurring bacteria in healthcare wastewater showed lower resistance patterns (D 10 values ranging between 0.21 ± 0.005 and 0.59 ± 0.005) compared to those obtained after Gamma irradiation (D 10 values ranging between 0.25 ± 0.015 and 0.70 ± 0.0001). Spores of Clostridium perfringens were the most resistant assayed microbes either after E-Beam (D 10 values of 3.74 ± 0.005) or Gamma irradiation (D 10 values of 4.77 ± 0.025) of collected samples. According to inactivation patterns, a dose of 10 kGy was sufficient for a complete inactivation of spores. Bacteriophages isolated from healthcare wastewater showed the same resistance patterns as those previously obtained in urban treated sewage and were inactivated using higher doses than waterborne bacteria (D 10 values of SOMCPH 1.46 ± 0.057; D 10 values of FRNAPH 1.03 ± 0.057). Their resistance to irradiation treatment in such complex matrix corroborates their use to survey the viral quality of healthcare wastewater before their discharge in the urban sanitation network. D 10 value analysis showed that bacteria and bacteriophages inactivation by E-Beam irradiation required lower doses than those required for their inactivation using Gamma rays. According to inactivation patterns, a dose of 7 kGy was sufficient for total inactivation of both pathogenic bacteria and viruses. Thus, E-Beam irradiation seems to be an efficient physical pre-treatment process for healthcare wastewater treatment prior to its discharge in urban sanitation system to ensure compliance with environmental standards and protect public health., (© 2022. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

UV light is a tool associated with the denaturation of cellular components, DNA damage, and cell disruption. UV treatment is widely used in the decontamination process; however, predicting a sufficient UV dose by using traditional methods is doubtful. In this study, an in-house UVC apparatus was designed to investigate the process of the inactivation of five indicator bacteria when the initial cell concentrations and irradiation intensities varied. Both linear and nonlinear mathematical models were applied to predict the inactivation kinetics. In comparison with the Weibull and modified Chick-Watson models, the Chick-Watson model provided a good fit of the experimental data for five bacteria, Escherichia coli, Klebsiella pneumoniae, Staphylococcus aureus, Streptococcus faecalis, and Bacillus subtilis. The specific death rate ( k d ) significantly increased when the irradiation intensity ( I ) increased from 1.41 W/m 2 to 3.02 W/m 2 and 4.83 W/m 2 ( P  < 0.05). Statistical analysis revealed no significant difference in the k d values among the groups of tested Gram-positive bacteria, Gram-negative bacteria, and B. subtilis spores, but the k d values differed among groups ( P  < 0.05). The death rate coefficient ( k ) varied from species to species. The k values of the tested Gram-positive bacteria were higher than those of the Gram-negative bacteria. The thick peptidoglycan layer in the Gram-positive membrane was responsible for UVC resistance. The high guanine-cytosine (GC) content in bacteria also contributed to UV resistance due to the less photoreactive sites on the nucleotides. This investigation provides a good understanding of bacterial inactivation induced by UVC treatment. IMPORTANCE Prevention and control measures for microbial pathogens have attracted worldwide attention due to the recent coronavirus disease 2019 pandemic. UV treatments are used as a commercial control to prevent microbial contamination in diverse applications. Microorganisms exhibit different UV sensitivities, which are often measured by the UV doses required for decreasing the number of microbial contaminants in the logarithmic order. The maximum efficacy of UV is usually observed at 254 nm (residing in the UVC range of the light spectrum). UV technology is a nonthermal physical decontamination measure that does not require any chemicals and consumes low levels of energy while leaving insignificant amounts of chemical residues or toxic compounds. Therefore, obtaining the microbial death kinetics and their intrinsic parameters provided in this study together with the UV photoreaction rate enables advancement in the design of UV treatment systems.

Improving the treatment efficiency of sludge in Alexandria, Egypt, was studied to improve the primary and secondary sludge treatment efficiency, different doses ranging from 0.25 to 6 kGy of ionizing radiation were proposed and evaluated. The scope of This study is to assess the radiation-based treatment efficiency from physical, chemical, and biological perspectives and to compare between the conventional treatment method and the radiation-based treatment technology. To evaluate the performance of each treatment system, pH, oil and greases concentrations, total solid concentrations, BOD concentrations, COD concentrations, parasites, and microorganisms were assessed in the primary and secondary samples at different radiation doses (from 0.25 to 6 KGy), and in the conventionally treated samples. Irradiation by gamma radiation with a dose ranging from 0.25 to 6 kGy was efficient in reducing some of the physical contaminants. Oil & greases, Total Solids, BOD, COD concentrations were reduced significantly (p < 0.001) in a dose-dependent manner. Either primary or secondary sludge samples, total solid reduced significantly to about one-third of control concentration at six kGy. Six kGy able to reduce the BOD and COD concentrations in the primary sludge samples to that of the treated (after sludge dewatering) samples or less respectively and saved the secondary treatment stage. In primary and secondary sludge samples culture, E. coli, Staphylococcus aureus, and Vibrio spp were isolated as heavy growth on different culture media in the samples before radiation. After exposure to increasing doses of radiation, the number of isolated organisms decreased, however, the growth of Proteus, Acinetobacter, and vipro organisms was detected but in small numbers. No growth of any organism was noted at 5 kGy. On the other hand, in the secondary sludge samples, Proteus was isolated as heavy growth before radiation and After exposure to increasing doses of radiation, Moraxella spp. organisms were detected but in small numbers. By increasing the radiation doses, the free-living ciliates were decreased in the primary and secondary sludge samples. The free-living ciliates disappeared completely at 3 kGy. In the primary and secondary sludge samples, free-living ciliates reduction efficiency at 0.25 kGy was equivalent to the conventional treatment methods. So, we can conclude that radiation technology using Gamma rays at a dose higher than 5 kGy with a dose rate of 1.095 kGy/h is an effective technology for domestic and industrial waste sludge treatment from the environmental perspective and an experimental pilot plant study is required to optimize the cost of wastewater treatment through the use of irradiation technology., (Copyright © 2022. Published by Elsevier Ltd.)

Cryo-electron microscopy has become an essential tool to understand structure and function of biological samples. Especially for pathogens, such as disease-causing bacteria and viruses, insights gained by cryo-EM can aid in developing cures. However, due to the biosafety restrictions of pathogens, samples are often treated by chemical fixation to render the pathogen inert, affecting the ultrastructure of the sample. Alternatively, researchers use in vitro or ex vivo models, which are non-pathogenic but lack the complexity of the pathogen of interest. Here we show that ultraviolet-C (UVC) radiation applied at cryogenic temperatures can be used to eliminate or dramatically reduce the infectivity of Vibrio cholerae and the bacterial virus, the ICP1 bacteriophage. We show no discernable structural impact of this treatment of either sample using two cryo-EM methods: cryo-electron tomography followed by sub-tomogram averaging, and single particle analysis (SPA). Additionally, we applied the UVC irradiation to the protein apoferritin (ApoF), which is a widely used test sample for high-resolution SPA studies. The UVC-treated ApoF sample resulted in a 2.1 Å structure indistinguishable from an untreated published map. This research demonstrates that UVC treatment is an effective and inexpensive addition to the cryo-EM sample preparation toolbox., (© 2022. The Author(s).)

Bacteria belonging to the group of ESKAPE pathogens are responsible for the majority of nosocomial infections. Due to the increase of antibiotic resistance, alternative treatment strategies are of high clinical relevance. In this context visible light as disinfection technique represents an interesting option as microbial pathogens can be inactivated without adjuvants. However cytotoxic effects of visible light on host cells have also been reported. We compared the cytotoxicity of violet and blue light irradiation on monocytic THP-1 and alveolar epithelium A549 cells with the inactivation effect on ESKAPE pathogens. THP-1 cells displayed a higher susceptibility to irradiation than A549 cells with first cytotoxic effects occurring at 300 J cm -2 (405 nm) and 400 J cm -2 (450 nm) in comparison to 300 J cm -2 and 1000 J cm -2 , respectively. We could define conditions in which a significant reduction of colony forming units for all ESKAPE pathogens, except Enterococcus faecium, was achieved at 405 nm while avoiding cytotoxicity. Irradiation at 450 nm demonstrated a more variable effect which was species and medium dependent. In summary a significant reduction of viable bacteria could be achieved at subtoxic irradiation doses, supporting a potential use of visible light as an antimicrobial agent in clinical settings., (© 2021. The Author(s).)

Viruses exert diverse ecosystem impacts by controlling their host community through lytic predator-prey dynamics. However, the mechanisms by which lysogenic viruses influence their host-microbial community are less clear. In hot springs, lysogeny is considered an active lifestyle, yet it has not been systematically studied in all habitats, with phototrophic microbial mats (PMMs) being particularly not studied. We carried out viral metagenomics following in situ mitomycin C induction experiments in PMMs from Porcelana hot spring (Northern Patagonia, Chile). The compositional changes of viral communities at two different sites were analyzed at the genomic and gene levels. Furthermore, the presence of integrated prophage sequences in environmental metagenome-assembled genomes from published Porcelana PMM metagenomes was analyzed. Our results suggest that virus-specific replicative cycles (lytic and lysogenic) were associated with specific host taxa with different metabolic capacities. One of the most abundant lytic viral groups corresponded to cyanophages, which would infect the cyanobacteria Fischerella , the most active and dominant primary producer in thermophilic PMMs. Likewise, lysogenic viruses were related exclusively to chemoheterotrophic bacteria from the phyla Proteobacteria , Firmicutes , and Actinobacteria . These temperate viruses possess accessory genes to sense or control stress-related processes in their hosts, such as sporulation and biofilm formation. Taken together, these observations suggest a nexus between the ecological role of the host (metabolism) and the type of viral lifestyle in thermophilic PMMs. This has direct implications in viral ecology, where the lysogenic-lytic switch is determined by nutrient abundance and microbial density but also by the metabolism type that prevails in the host community. IMPORTANCE Hot springs harbor microbial communities dominated by a limited variety of microorganisms and, as such, have become a model for studying community ecology and understanding how biotic and abiotic interactions shape their structure. Viruses in hot springs are shown to be ubiquitous, numerous, and active components of these communities. However, lytic and lysogenic viral communities of thermophilic phototrophic microbial mats (PMMs) remain largely unexplored. In this work, we use the power of viral metagenomics to reveal changes in the viral community following a mitomycin C induction experiment in PMMs. The importance of our research is that it will improve our understanding of viral lifestyles in PMMs via exploring the differences in the composition of natural and induced viral communities at the genome and gene levels. This novel information will contribute to deciphering which biotic and abiotic factors may control the transitions between lytic and lysogenic cycles in these extreme environments.

Light is essential for plant life. It provides a source of energy through photosynthesis and regulates plant growth and development and other cellular processes, such as by controlling the endogenous circadian clock. Light intensity, quality, duration and timing are all important determinants of plant responses, especially to biotic stress. Red light can positively influence plant defence mechanisms against different pathogens, but the molecular mechanism behind this phenomenon is not fully understood. Therefore, we reviewed the impact of red light on plant biotic stress responses against viruses, bacteria, fungi and nematodes, with a focus on the physiological effects of red light treatment and hormonal crosstalk under biotic stress in plants. We found evidence suggesting that exposing plants to red light increases levels of salicylic acid (SA) and induces SA signalling mediating the production of reactive oxygen species, with substantial differences between species and plant organs. Such changes in SA levels could be vital for plants to survive infections. Therefore, the application of red light provides a multidimensional aspect to developing innovative and environmentally friendly approaches to plant and crop disease management., (© 2021 The Authors. Plant, Cell & Environment published by John Wiley & Sons Ltd.)

Pulsed Nd-YAG laser irradiation of bacteria has been suggested as a possible means of treating contaminated intra-oral sites although relatively few studies have been conducted. In this investigation, the antimicrobial activity of a pulsed Nd-YAG laser was assessed in vitro for a range of oral bacteria using several pulse energies and exposure durations. Pure cultures of each organism were lased in saline suspensions followed by standard colony counting techniques for test and control samples. Microbial inhibition was found to be organism-dependent and varied with energy dose and pulse energy. For all nine test species 120-mJ laser pulses proved more efficient than 80-mJ pulses, with 99.9% kills compared with around 90% kills after exposure to 1800 pulses. These killing activity levels compare favourably with those achieved with other lasers in vitro. [ABSTRACT FROM AUTHOR]

Antimicrobial resistance is a global, mounting and dynamic issue that poses an immediate threat to human, animal, and environmental health. Among the alternative antimicrobial treatments proposed to reduce the external use of antibiotics is electromagnetic radiation, such as blue light. The prevailing mechanistic model is that blue light can be absorbed by endogenous porphyrins within the bacterial cell, inducing the production of reactive oxygen species, which subsequently inflict oxidative damages upon different cellular components. Nevertheless, it is unclear whether other mechanisms are involved, particularly those that can affect the efficacy of antimicrobial blue light treatments. In this review, we summarize evidence of inherent factors that may confer protection to a selected group of bacteria against blue light-induced oxidative damages or modulate the physiological characteristics of the treated bacteria, such as virulence and motility. These include descriptions of three major photoreceptors in bacteria, chemoreceptors, SOS-dependent DNA repair and non-SOS protective mechanisms. Future directions are also provided to assist with research efforts to increase the efficacy of antimicrobial blue light and to minimize the development of blue light-tolerant phenotypes.

New Pb(II), Mn(II), Hg(II), and Zn(II) complexes, derived from 4-(4-chlorophenyl)-1-(2-(phenylamino)acetyl)thiosemicarbazone, were synthesized. The compounds with general formulas, [Pb(H 2 L) 2 (OAc) 2 ]ETOH.H 2 O, [Mn(H 2 L)(HL)]Cl, [Hg 2 (H 2 L)(OH)SO 4 ], and [Zn(H 2 L)(HL)]Cl, were characterized by physicochemical and theoretical studies. X-ray diffraction studies showed a decrease in the crystalline size of compounds that were exposed to gamma irradiation (γ-irradiation). Thermal studies of the synthesized complexes showed thermal stability of the Mn(II) and Pb(II) complexes after γ-irradiation compared to those before γ-irradiation, while no changes in the Zn(II) and Hg(II) complexes were observed. The optimized geometric structures of the ligand and metal complexes are discussed regarding density functional theory calculations (DFT). The antimicrobial activities of the ligand and metal complexes against several bacterial and fungal stains were screened before and after irradiation. The Hg(II) complex has shown excellent antibacterial activity before and after γ-irradiation. In vitro cytotoxicity screening of the ligand and the Mn(II) and Zn(II) complexes before and after γ-irradiation disclosed that both the ligand and Mn(II) complex exhibited higher activity against human liver (Hep-G2) than Zn(II). Molecular docking was performed on the active site of MK-2 and showed good results.

A growing number of known species possess a remarkable characteristic - extreme resistance to the effects of ionizing radiation (IR). This review examines our current understanding of how organisms can adapt to and survive exposure to IR, one of the most toxic stressors known. The study of natural extremophiles such as Deinococcus radiodurans has revealed much. However, the evolution of Deinococcus was not driven by IR. Another approach, pioneered by Evelyn Witkin in 1946, is to utilize experimental evolution. Contributions to the IR-resistance phenotype affect multiple aspects of cell physiology, including DNA repair, removal of reactive oxygen species, the structure and packaging of DNA and the cell itself, and repair of iron-sulfur centers. Based on progress to date, we overview the diversity of mechanisms that can contribute to biological IR resistance arising as a result of either natural or experimental evolution., Competing Interests: Declaration of interests The authors declare no conflicts of interest., (Copyright © 2021 Elsevier Ltd. All rights reserved.)

Electrons with energies of 300 keV or lower have the potential to decontaminate the surfaces of various types of food products with minimal loss of quality. The aim of the present work was to determine the thickness of the layer inhabited by microorganisms. The food samples tested were black and white pepper irradiated with 200 keV, 230 keV, 300 keV and 9 MeV beams of electron energy. To determine the depth from the surface which can be inhabited by microorganisms two approaches were tested. The methods used were based on the application of different microbiological recovery techniques and the microbial effectiveness of the irradiation process depending on the energy of the electron beam. It was observed that the layer which microorganisms may contaminate differed for the tested samples it was estimated as being below 100 μm thick for white pepper and about 200 μm for black pepper. The penetration ability was significant in experiments performed, and as a result the electron beam at the lowest levels tested (200 and 230 keV) was found to be insufficient to effectively decontaminate the black pepper samples. The beam of energy 300 keV was found to have a similar microbial inactivation effect as the high energy electron beam (9 MeV)., (Copyright © 2021 Elsevier Ltd. All rights reserved.)

Hundreds of thousands of human implant procedures require surgical revision each year due to infection. Infections are difficult to treat with conventional antibiotics due to the formation of biofilm on the implant surface. We have developed a noninvasive method to eliminate biofilm on metal implants using heat generated by intermittent alternating magnetic fields (iAMF). Here, we demonstrate that heat and antibiotics are synergistic in biofilm elimination. For Pseudomonas aeruginosa biofilm, bacterial burden was reduced >3 log with iAMF and ciprofloxacin after 24 h compared with either treatment alone (p < 0.0001). This effect was not limited by pathogen or antibiotic as similar biofilm reductions were seen with iAMF and either linezolid or ceftriaxone in Staphylococcus aureus. iAMF and antibiotic efficacy was seen across various iAMF settings, including different iAMF target temperatures, dose durations, and dosing intervals. Initial mechanistic studies revealed membrane disruption as one factor important for AMF enhanced antibacterial activity in the biofilm setting. This study demonstrates the potential of utilizing a noninvasive approach to reduce biofilm off of metallic implants., (© 2021. The Author(s).)

Radiations emitted by low power radiation sources have been applied for therapeutic proposals due to their capacity of inactivating bacteria and cancer cells in photodynamic therapy and stimulating tissue cells in photobiomodulation. Exposure to these radiations could increase cell proliferation in bacterial cultures under stressful conditions. Cells in infected or not infected tissue injuries are also under stressful conditions and photobiomodulation-induced regenerative effect on tissue injuries could be related to effects on stressed cells. The understanding of the effects on cells under stressful conditions could render therapies based on photobiomodulation more efficient as well as expand them. Thus, the objective of this review was to update the studies reporting photobiomodulation on prokaryotic and eukaryotic cells under stress conditions. Exposure to radiations emitted by low power radiation sources could induce adaptive responses enabling cells to survive in stressful conditions, such as those experienced by bacteria in their host and by eukaryotic cells in injured tissues. Adaptive responses could be the basis for clinical photobiomodulation applications, either considering their contraindication for treatment of infected injuries or indication for treatment of injuries, inflammatory process resolution, or tissue regeneration., (© 2021. Springer-Verlag London Ltd., part of Springer Nature.)

A growing body of literature has recognized the non-thermal effect of pulsed microwave radiation (PMR) on bacterial systems. However, its mode of action in deactivating bacteria has not yet been extensively investigated. Nevertheless, it is highly important to advance the applications of PMR from simple to complex biological systems. In this study, we first optimized the conditions of the PMR device and we assessed the results by simulations, using ANSYS HFSS (High Frequency Structure Simulator) and a 3D particle-in-cell code for the electron behavior, to provide a better overview of the bacterial cell exposure to microwave radiation. To determine the sensitivity of PMR, Escherichia coli and Staphylococcus aureus cultures were exposed to PMR (pulse duration: 60 ns, peak frequency: 3.5 GHz) with power density of 17 kW/cm 2 at the free space of sample position, which would induce electric field of 8.0 kV/cm inside the PBS solution of falcon tube in this experiment at 25 °C. At various discharges (D) of microwaves, the colony forming unit curves were analyzed. The highest ratios of viable count reductions were observed when the doses were increased from 20D to 80D, which resulted in an approximate 6 log reduction in E. coli and 4 log reduction in S. aureus. Moreover, scanning electron microscopy also revealed surface damage in both bacterial strains after PMR exposure. The bacterial inactivation was attributed to the deactivation of oxidation-regulating genes and DNA damage.

The pandemic created by SARS-CoV-2 has caused a shortage in the supplies of N95 filtering facepiece respirators (FFRs), disposable respirators with at least 95% efficiency to remove non-oily airborne particles, due to increasing cases all over the world. The current article reviewed various possible decontamination methods for FFR reuse including ultraviolet germicidal irradiation (UVGI), hydrogen peroxide vapor (HPV), microwave-generated steam (MGS), hydrogen peroxide gas plasma (HPGP), and 70% or higher ethanol solution. HPV decontamination was effective against bacterial spores (6 log 10 reduction of Geobacillus stearothermophilus spores) on FFRs and viruses (> 4 log 10 reduction of various types of viruses) on inanimate surfaces, and no degradation of respirator materials and fit has been reported. 70% or higher ethanol decontamination showed high efficacy in inactivation of coronaviruses on inanimate surfaces (> 3.9 log 10 reduction) but it was lower on FFRs which filtration efficiency was also decreased. UVGI method had good biocidal efficacy on FFRs (> 3 log 10 reduction of H1N1 virus) combined with inexpensive, readily available equipment; however, it was more time-consuming to ensure sufficient reduction in SARS-CoV-2. MGS treatment also provided good viral decontamination on FFRs (> 4 log 10 reduction of H1N1 virus) along with less time-intensive process and readily available equipment while inconsistent disinfection on the treated surfaces and deterioration of nose cushion of FFRs were observed. HPGP was a good virucidal system (> 6 log 10 reduction of Vesicular stomatitis virus) but filtration efficiency after decontamination was inconsistent. Overall, HPV appeared to be one of the most promising methods based on the high biocidal efficacy on FFRs, preservation of respirator performance after multiple cycles, and no residual chemical toxicity. Nonetheless, equipment cost and time of the HPV process and a suitable operating room need to be considered., (© 2021. The Author(s), under exclusive licence to European Photochemistry Association, European Society for Photobiology.)

In this study, we investigated the effects of an ultrasonically activated stream (UAS) on the removal of microbial contaminants from spinach leaves. The microbial loads on samples cleaned with and without UAS were enumerated using the cell culture method and compared against unwashed samples on day 0 and day 6 after cleaning. The effects of UAS cleaning on leaf quality were also examined through both macroscopic and microscopic inspection, as well as measurement of the electrolyte leakage rate. Results showed that the microbial load on samples cleaned with UAS for 2 min was significantly lower on day 6 after cleaning than on those treated without ultrasound. Comparison between the cleaning effects of UAS for 40 s versus 2 min indicated that a cleaning duration of 2 min allowed sufficient time for UAS to disaggregate and detach the microbial contamination more effectively. In this case, the induction of bacteria into a viable but non-culturable state does not affect the shelf-life test results as much as it does with a 40 s clean. UAS cleaning for 2 min did not produce significant surface damage, which can affect overall leaf quality. These findings highlight the potential of UAS systems in the salad industry to improve the microbiological quality and shelf life of salads., Competing Interests: Conflict of interest disclosure The principal investigator (T.G.L.) is the inventor of the device used in the experimental work, and is a director and inventor-in-chief of the company (Sloan Water Technology, Ltd) which owns the rights to the technology. However, he has taken no salary or other remuneration for these roles. Another author (C.N.D.) is currently an employee of that company., (Copyright © 2021 World Federation for Ultrasound in Medicine & Biology. Published by Elsevier Inc. All rights reserved.)

Bacterial infection is a universal threat to public health, which not only causes many serious diseases but also exacerbates the condition of the patients of cancer, pandemic diseases, e.g. , COVID-19, and so on. Antibiotic therapy has been used to be an effective way for common bacterial disinfection. However, due to the misuse and abuse of antibiotics, more and more antibiotic-resistant bacteria have emerged as fatal threats to human beings. At present, more than 700,000 patients die every year with bacterial infections because of the lack of effective treatment. It is frustrating that the pace of development of antibiotics lags far behind that of bacterial resistance, with an estimation of 10 million deaths per year from bacterial infections after 2050. Facing such a rigorous challenge, approaches for bacterial disinfection are urgently demanded. The recently developed near-infrared (NIR) light-irradiation-based bacterial disinfection is highly promising to shatter bacterial resistance by employing NIR light-responsive materials as mediums to generate antibacterial factors such as heat, reactive oxygen species (ROS), and so on. This treatment approach is proved to be a potent candidate to accurately realize spatiotemporal control, while effectively eradicating multidrug-resistant bacteria and inhibiting antibiotic resistance. Herein, we summarize the latest progress of NIR light-based bacterial disinfection. Ultimately, current challenges and perspectives in this field are discussed.

Cyclic actuation is critical for driving motion and transport in living systems, ranging from oscillatory motion of bacterial flagella to the rhythmic gait of terrestrial animals. These processes often rely on dynamic and responsive networks of oscillators-a regulatory control system that is challenging to replicate in synthetic active matter. Here, we describe a versatile platform of light-driven active particles with interaction geometries that can be reconfigured on demand, enabling the construction of oscillator and spinner networks. We employ optically induced Marangoni trapping of particles confined to an air-water interface and subjected to patterned illumination. Thermal interactions among multiple particles give rise to complex coupled oscillatory and rotational motions, thus opening frontiers in the design of reconfigurable, multiparticle networks exhibiting collective behavior., Competing Interests: The authors declare no competing interest.

Ultraviolet blood irradiation (UBI) was used with success in the 1930s and 1940s for a variety of diseases. Despite the success, the lack of understanding of the detailed mechanisms of actions, and the achievements of antibiotics, phased off the use of UBI from the 1950s. The emergence of novel viral infections, from HIV/AIDS to Ebola, from SARS and MERS, and SARS-CoV-2, bring back the attention to this therapeutical opportunity. UBI has a complex virucidal activity, mostly acting on the immune system response. It has effects on lymphocytes (T-cells and B-cells), macrophages, monocytes, dendritic cells, low-density lipoprotein (LDL), and lipids. The Knott technique was applied for bacterial infections such as tuberculosis to viral infections such as hepatitis or influenza. The more complex extracorporeal photopheresis (ECP) is also being applied to hematological cancers such as T-cell lymphomas. Further studies of UBI may help to create a useful device that may find applications for novel viruses that are resistant to known antivirals or vaccines, or also bacteria that are resistant to known antibiotics.

The oxidative stress response represents a sum of antioxidative mechanisms that are essential for determining the adaptation and abundance of microorganisms in the environment. Leptospirillum ferriphilum and Acidithiobacillus ferrooxidans are chemolithotrophic bacteria that obtain their energy from the oxidation of ferrous ion. Both microorganisms are important for bioleaching of sulfidic ores and both are tolerant to high levels of heavy metals and other factors that can induce oxidative stress. In this work, we compared the tolerance and response of L. ferriphilum and At. ferrooxidans to Fe 3+ , H 2 O 2 , K 2 CrO 4 , and UV-C radiation. We evaluated growth, generation of reactive oxygen species (ROS), oxidative damage to lipid membranes and DNA, and the activity of antioxidative proteins in cells exposed to these stressors. L. ferriphilum had higher cell density, lower ROS content and less lipid and DNA damage than At. ferrooxidans. Consistent with this, the activity levels of thioredoxin and superoxide dismutase in L. ferriphilum were upregulated and higher than in At. ferrooxidans. This indicated that L. ferriphilum has a higher capacity to respond to oxidative stress and to manage redox homeostasis. This capacity could largely contribute to the high abundance of this species in natural and anthropogenic sites., Competing Interests: Declaration of competing interest The authors declare no conflict of interest., (Copyright © 2021 Institut Pasteur. Published by Elsevier Masson SAS. All rights reserved.)

Photodynamic inactivation (PDI) is a promising approach for the efficient killing of pathogenic microbes. In this study, the photodynamic effect of sulfonated polystyrene nanoparticles with encapsulated hydrophobic 5,10,15,20-tetraphenylporphyrin (TPP-NP) photosensitizers on Gram-positive (including multi-resistant) and Gram-negative bacterial strains was investigated. The cell viability was determined by the colony forming unit method. The results showed no dark cytotoxicity but high phototoxicity within the tested conditions. Gram-positive bacteria were more sensitive to TPP-NPs than Gram-negative bacteria. Atomic force microscopy was used to detect changes in the morphological properties of bacteria before and after the PDI treatment.