Molecular mechanisms of ultraviolet radiation-induced DNA damage and repair

LED induced non-thermal preservation of muscle foods: A systematic review

LED technology has emerged as a promising non-thermal preservation method for highly perishable muscle foods like meat and fish. Muscle foods are most susceptible to spoilage due to their high moisture content and nutrient density, which create an ideal environment for microbial growth, chemical oxidation, and enzymatic activity, which negatively alter their quality. LED treatment offers an effective solution by significantly reducing microbial loads and extending shelf life without adversely affecting sensory and nutritional properties. Specific wavelengths of LED light induce microbial inactivation through mechanisms like DNA damage, lipid oxidation, and protein alteration. Studies have shown that LED treatment can preserve the fresh-like quality of muscle foods by mitigating common spoilage processes. The advantages of LED technology include its non-thermal nature, ability to integrate with other preservation methods, and controllability in terms of intensity and wavelength. This enables for tailored applications based on food type and spoilage risks. As consumer demand grows for safe, chemical-free food options, LED technology addresses this need while enhancing food safety and quality. Further research is encouraged to optimize LED applications in various muscle food preservation contexts. With its exceptional ability to produce DNA damage in bacteria, inactivate enzymes, and malfunction biological activities, LED could serve as an inexpensive processing intervention to safeguard the quality of meat and seafood products. This review underscores the potential of LED technology as a promising alternative to traditional preservation methods for decontamination of muscle food.

High-glucose impact on UVB responses in human epidermal keratinocytes: Insights on diabetic skin's resistance to photocarcinogenesis

Ultraviolet (UV) B-induced damage in human epidermal keratinocytes (HEKs) initiates photocarcinogenesis. However, how diabetes influences photocarcinogenesis is not well understood. To investigate the impact of high-glucose environments on responses to UVB, we cultured HEKs in normal-glucose (NG) or high-glucose (HG) conditions (G6 and G26), followed by UVB irradiation at 25 mJ/cm2 (G6UVB and G26UVB). We performed next-generation sequencing and analyzed HEKs' expression profiles bioinformatically to identify candidate genes and cellular responses involved. We found UVB induced consistent responses in both NG- and HG-cultivated HEKs, but it also triggered certain distinct processes and pathways specifically in the HG groups. The 459 differentially expressed (DE) genes in the HG groups revealed their roles in chromatin remodeling, nucleosome assembly, and interferon signaling activation. Moreover, the 29 DE genes identified in G26UVB/G6UVB comparison, including the potent tumor suppressor gene TFPI2, were considered key genes contributing to HEKs' altered response to UVB in HG environments. UVB irradiation induced significantly higher TFPI2 expression in HG-cultivated HEKs than their NG-cultivated counterpart. Finally, HG-cultivation significantly increased oxidative stress, cyclobutane pyrimidine dimer formation, and apoptosis, while reducing HEKs' viability after UVB irradiation. These changes under HG conditions probably mediate cell fate toward death and tumor regression. Overall, our findings provide evidence and associated molecular basis on how HG conditions reduce keratinocytes' photocarcinogenic potential following UVB exposure.

The in vitro effect riboflavin combined with or without UVA in Acanthamoeba castellanii

The anti-Acanthamoeba properties of riboflavin and its enhanced amoebicidal effects when combined with ultraviolet A (UVA) radiation were investigated in vitro. The viability of cultured Acanthamoeba castellanii was assessed by adding varying concentrations (0 ~ 0.2% w/v) of riboflavin to the culture medium or after combined riboflavin and UVA treatment (30 min, 3 mW/cm2) over 1, 3, 5, and 7 days. Intracellular reactive oxygen species (ROS) levels were measured following a 30-minute exposure to riboflavin. Additionally, the cysticidal effects of riboflavin, UVA, and their combination were evaluated. Gene transcription in Acanthamoeba was analyzed using RNA-seq. Riboflavin demonstrated dose-dependent toxicity on Acanthamoeba, accompanied by an increase in intracellular ROS. Exposure to 0.2% riboflavin reduced Acanthamoeba viability by over 50% within one day. UVA treatment alone also reduced viability by over 50%. Combined treatment with 0.2% riboflavin decreased trophozoite survival by more than 80%, and approximately 60% of cysts were killed when 0.1% riboflavin was combined with UVA. RNA-seq analysis indicated significant changes in gene expression after exposure to riboflavin, UVA, and their combination, particularly affecting oxidoreductase activity, cystathionine β synthase, and serine-threonine kinase activity. These findings indicate that riboflavin exhibits dose-dependent toxicity in Acanthamoeba, primarily through increased ROS generation. Combining riboflavin and UVA did not fully eradicate trophozoites and cysts of Acanthamoeba, but was able to partially inactivate them.

Downregulation of carnitine acetyltransferase by promoter hypermethylation regulates ultraviolet-induced matrix metalloproteinase-1 expression in human dermal fibroblasts

BACKGROUND

Overexposure to ultraviolet (UV) radiation accelerates skin aging, resulting in wrinkle formation, reduced skin elasticity, and hyperpigmentation. UV irradiation induces increased matrix metalloproteinases (MMPs) that degrade collagen in the extracellular matrix. Skin aging is also accompanied by epigenetic alterations such as promoter methylation by DNA methyltransferases, leading to the activation or suppression of gene expression. Although carnitine acetyltransferase (CRAT) is implicated in aging, the effect of UV on the expression of CRAT and regulatory mechanisms of UV-induced MMP-1 expression remain unknown.

OBJECTIVE

We investigated changes in CRAT expression upon UV irradiation and its effect on MMP-1 expression.

METHODS

Primary human dermal fibroblasts were UV irradiated with either control or 5-AZA-dC. CRAT knockdown or overexpression was performed to investigate its effect on MMP-1 expression. The mRNA level was analyzed by quantitative real-time PCR, and protein level by western blotting.

RESULTS

The expression of CRAT was decreased in UV-irradiated human skin in vivo and in human dermal fibroblasts in vitro. CRAT was downregulated upon UV irradiation by hypermethylation, and treatment with 5-Aza-2'-deoxycytidine, a DNA methyltransferase inhibitor, reversed UV-induced downregulation of CRAT. CRAT knockdown activated the JNK, ERK, and p38 MAPK signaling pathways, which increased MMP-1 expression. Stable overexpression of CRAT alleviated UV-induced MMP-1 induction.

CONCLUSION

CRAT downregulation caused by promoter hypermethylation may play an important role in UV-induced skin aging via upregulation of MMP-1 expression.

Protein Recruitment to Dynamic DNA-RNA Host Condensates

We describe the design and characterization of artificial nucleic acid condensates that are engineered to recruit and locally concentrate proteins of interest in vitro. These condensates emerge from the programmed interactions of nanostructured motifs assembling from three DNA strands and one RNA strand that can include an aptamer domain for the recruitment of a target protein. Because condensates are designed to form regardless of the presence of target protein, they function as "host" compartments. As a model protein, we consider Streptavidin (SA) due to its widespread use in binding assays. In addition to demonstrating protein recruitment, we describe two approaches to control the onset of condensation and protein recruitment. The first approach uses UV irradiation, a physical stimulus that bypasses the need for exchanging molecular inputs and is particularly convenient to control condensation in emulsion droplets. The second approach uses RNA transcription, a ubiquitous biochemical reaction that is central to the development of the next generation of living materials. We then show that the combination of RNA transcription and degradation leads to an autonomous dissipative system in which host condensates and protein recruitment occur transiently and that the host condensate size as well as the time scale of the transition can be controlled by the level of RNA-degrading enzyme. We conclude by demonstrating that biotinylated beads can be recruited to SA-host condensates, which may therefore find immediate use for the physical separation of a variety of biotin-tagged components.

Mutation profiling through whole genome sequencing of electron beam-induced black gram (Vigna mungo L. Hepper) mutant

PURPOSE

Black gram (Vigna mungo [L.] Hepper) is an important annual legume with great economic, nutritional and ecological significance. Novel variations through induced mutagenesis can accelerate narrow genetic base-impeded black gram improvement. This is a first study on characterization of genome-wide mutation spectrum induced by electron beam (EB).

MATERIALS AND METHODS

Black gram genotype 'Pant U-31' was irradiated with 400 Gy EB generated in a 10 MeV LINAC. A stable mutant PM-32 (M6) was re-sequenced by combining Illumina (BIOO Scientific, Inc., Austin, TX) and Nanopore Technologies (Oxford, UK). Variants were predicted in reference to the available whole genome scaffold level draft assembly of parent 'Pant U-31'.

RESULTS

Genome analysis predicted a total of 76,893 genes of which 58,517 were annotated. The identified variants totaling 728,161, largely comprised (91.56%) of single base substitutions (SBSs) with a transition (Ti) to transversion (Tv) ratio of 1.95. Of the indels constituting 8.44% of total induced variants, insertions accounted for 4.29%, with preponderance of multiple bases (53.63%) and 2-5 bp insertions as the major class (33.71%). Multiple-base deletions (2-5 bases) formed the bulk (31.14%) of the total deletions. The genic variants (2438) with estimated high and moderate effects were located within 1271 predicted genes. A higher number of mutations were observed on chromosomes Vm1 (588) and Vm3 (428) with the highest frequency on chromosome Vm3 (every 0.07 Mb).

CONCLUSIONS

Our study reiterated the mutagenic utility of EB for inducing SBSs and small indels genome-wide. The knowledge gained from SNP-level profiling of EB-induced mutations can expedite comparative mutation breeding studies in legumes.

From silence to symphony: transcriptional repression and recovery in response to DNA damage

Genotoxic stress resulting from DNA damage is resolved through a signaling cascade known as the DNA Damage Response (DDR). The repair of damaged DNA is essential for cell survival, often requiring the DDR to attenuate other cellular processes such as the cell cycle, DNA replication, and transcription of genes not involved in DDR. The complex relationship between DDR and transcription has only recently been investigated. Transcription can facilitate the DDR in response to double-strand breaks (DSBs) and stimulate nucleotide excision repair (NER). However, transcription may need to be reduced to prevent potential interference with the repair machinery. In this review, we discuss various mechanisms that regulate transcription repression in response to different types of DNA damage, categorizing them by their range and duration of effect. Finally, we explore various models of transcription recovery following DNA damage-induced repression.

CS proteins and ubiquitination: orchestrating DNA repair with transcription and cell division

To face genotoxic stress, eukaryotic cells evolved extremely refined mechanisms. Defects in counteracting the threat imposed by DNA damage underlie the rare disease Cockayne syndrome (CS), which arises from mutations in the CSA and CSB genes. Although initially defined as DNA repair proteins, recent work shows that CSA and CSB act instead as master regulators of the integrated response to genomic stress by coordinating DNA repair with transcription and cell division. CSA and CSB exert this function through the ubiquitination of target proteins, which are effectors/regulators of these processes. This review describes how the ubiquitination of target substrates is a common denominator by which CSA and CSB participate in different aspects of cellular life and how their mutation gives rise to the complex disease CS.

An Ecofriendly Nature-Inspired Microcarrier for Enhancing Delivery, Stability, and Biocidal Efficacy of Phage-Based Biopesticides

In pursuit of sustainable agricultural production, the development of environmentally friendly and effective biopesticides is essential to improve food security and environmental sustainability. Bacteriophages, as emerging biocontrol agents, offer an alternative to conventional antibiotics and synthetic chemical pesticides. The primary challenges in applying phage-based biopesticides in agricultural settings are their inherent fragility and low biocidal efficacy, particularly the susceptibility to sunlight exposure. This study addresses the aforementioned challenges by innovatively encapsulating phages in sporopollenin exine capsules (SECs), which are derived from plant pollen grains. The size of the apertures on SECs could be controlled through a non-thermal and rapid process, combining reinflation and vacuum infusion techniques. This unique feature facilitates the high-efficiency encapsulation and controlled release of phages under various conditions. The proposed SECs could encapsulate over 9 log PFU g-1 of phages and significantly enhance the ultraviolet (UV) resistance of phages, thereby ensuring their enhanced survivability and antimicrobial efficacy. The effectiveness of SECs encapsulated phages (T7@SECs) in preventing and treating bacterial contamination on lettuce leaves is further demonstrated, highlighting the practical applicability of this novel biopesticide in field applications. Overall, this study exploits the potential of SECs in the development of phage-based biopesticides, presenting a promising strategy to enhancing agricultural sustainability.

Insight into Single-Molecule Imaging Techniques for the Study of Prokaryotic Genome Maintenance

Genome maintenance comprises a group of complex and interrelated processes crucial for preserving and safeguarding genetic information within all organisms. Key aspects of genome maintenance involve DNA replication, transcription, recombination, and repair. Improper regulation of these processes could cause genetic changes, potentially leading to antibiotic resistance in bacterial populations. Due to the complexity of these processes, ensemble averaging studies may not provide the level of detail required to capture the full spectrum of molecular behaviors and dynamics of each individual biomolecule. Therefore, researchers have increasingly turned to single-molecule approaches, as these techniques allow for the direct observation and manipulation of individual biomolecules, and offer a level of detail that is unattainable with traditional ensemble methods. In this review, we provide an overview of recent in vitro and in vivo single-molecule imaging approaches employed to study the complex processes involved in prokaryotic genome maintenance. We will first highlight the principles of imaging techniques such as total internal reflection fluorescence microscopy and atomic force microscopy, primarily used for in vitro studies, and highly inclined and laminated optical sheet and super-resolution microscopy, mainly employed in in vivo studies. We then demonstrate how applying these single-molecule techniques has enabled the direct visualization of biological processes such as replication, transcription, DNA repair, and recombination in real time. Finally, we will showcase the results obtained from super-resolution microscopy approaches, which have provided unprecedented insights into the spatial organization of different biomolecules within bacterial organisms.

Design and Characterization of Liposomal-Based Carriers for the Encapsulation of Rosa canina Fruit Extract: In Vitro Gastrointestinal Release Behavior

The increasing demand for natural compounds as an alternative to synthetic antioxidants and conservans has led to the utilization of secondary plant metabolites in the food industry, as these bioactive compounds possess great antioxidative and antimicrobial properties without side effects on human health. Despite this, the sensitivity of plant-derived compounds is a restrictive factor in terms of their full potential. The current research aimed to characterize rosehip-fruit-extract-loaded liposomes (non-treated and UV-irradiated) in terms of their density, surface tension, viscosity, chemical composition (FTIR and HPLC analyses), and thermal behavior. In the storage stability study, the vesicle size, polydispersity index (PDI), zeta potential, conductivity, and mobility of the liposomes were monitored. FTIR analysis confirmed that the plant compounds were successfully loaded within the carrier, while no chemical reaction between the rosehip fruit extract and phospholipids was detected. The results of the HPLC analysis evidence the high potential for liposomal encapsulation to protect sensitive bioactives in the rosehip fruit extract from the degrading effect of UV irradiation. The size of the rosehip-fruit-extract-encapsulated liposomes increased on the seventh day of storage from 250 nm to 300 nm, while the zeta potential values were between -21 mV and -30 mV in the same period and further stabilized over 60 days of monitoring. In Vitro release studies in water and simulated gastrointestinal fluids showed that the presence of enzymes and bile salts (in intestinal fluid) enhanced the rosehip-polyphenol permeability from liposomes (70.3% after 6 h) compared with their release in water after 24 h and in gastric fluid after 4 h (38.9% and 41.4%, respectively). The obtained results indicate that the proliposome method was an effective method for rosehip fruit extract liposomal encapsulation and for the delivery of these plant-derived bioactives in foods.

Enhanced inactivation of Aspergillus niger biofilms by the combination of UV-LEDs with chlorine-based disinfectants

The presence of pathogenic fungal biofilms in drinking water distribution systems poses significant challenges in maintaining the safety of drinking water. This research delved into the formation of Aspergillus niger (A. niger) biofilms and evaluated their susceptibility to inactivation using combinations of ultraviolet light emitting diodes (UV-LEDs) with chlorine-based disinfectants, including UV-LEDs/chlorine (Cl2), UV-LEDs/chlorine dioxide (ClO2), and UV-LEDs/chloramine (NH2Cl) at 265 nm, 280 nm and 265/280 nm. Results indicated that A. niger biofilms reached initial maturity within 24 h, with matured three-dimensional filamentous structures and conidiospores by 96 h. UV-LEDs combined with chlorine-based disinfectants enhanced A. niger biofilm inactivation compared to UV-LEDs alone and low-pressure UV combined with chlorine-based disinfectants. At an UV fluence of 400 mJ/cm2, log reductions of UV265, UV280, and UV265/280 combined with chlorine-based disinfectants were 2.95-fold, 3.20-fold, and 2.38-fold higher than that of UV265, UV280, and UV265/280, respectively. During the inactivation, A. niger biofilm cells experienced increased membrane permeability and intracellular reactive oxygen species levels, resulting in cellular apoptosis. Extracellular polymeric substances contributed to the higher resistance of biofilms. Regarding electrical energy consumption, the order was: UV-LEDs/ClO2 > UV-LEDs/NH2Cl > UV-LEDs/Cl2. These findings provide insights into the effective utilization of UV-LEDs for fungal biofilm disinfection.

Molecular dynamics of DNA repair and carcinogen interaction: Implications for cancer initiation, progression, and therapeutic strategies

The integrity of the genetic material in human cells is continuously challenged by environmental agents and endogenous stresses. Among these, environmental carcinogens are pivotal in initiating complex DNA lesions that can lead to malignant transformations if not properly repaired. This review synthesizes current knowledge on the molecular dynamics of DNA repair mechanisms and their interplay with various environmental carcinogens, providing a comprehensive overview of how these interactions contribute to cancer initiation and progression. We examine key DNA repair pathways including base excision repair, nucleotide excision repair, and double-strand break repair and their regulatory networks, highlighting how defects in these pathways can exacerbate carcinogen-induced damage. Further, we discuss how understanding these molecular interactions offers novel insights into potential therapeutic strategies. This includes leveraging synthetic lethality concepts and designing targeted therapies that exploit specific DNA repair vulnerabilities in cancer cells. By integrating recent advances in molecular biology, genetics, and oncology, this review aims to illuminate the complex landscape of DNA repair and carcinogen-induced carcinogenesis, setting the stage for future research and therapeutic innovations.

Self-Assembled Hybrid Halide Perovskite Quantum Wire Bundle/Dot for Multiband Applications

In this study, self-assembled halide perovskite quantum wire bundles (QWBs)/quantum dots (QDs) are fabricated using a room temperature-based formation method. The one-dimensional (1D) perovskite-based QWB structures incorporate zero-dimensional QDs within a composite quantum structure. Transmission electron microscopy reveals that quantum wires with diameters ranging from tens of nanometers to approximately 200 nm maintain a single-crystal atomic arrangement in a bundle form. Conversely, QDs are uniformly distributed within the single-phase wire and appear as black dots < 10 nm. Photoluminescence analysis identifies the multiband characteristics of the emissions. The 420-440 nm band is attributed to 1D QWB, whereas the peak appearing in the 530-550 nm range corresponds to lead halide PbBr2 QDs. Thus, the proposed self-assembled 1D QWB/QD composite structure exhibits novel multiband physical properties in the 420-440 and 530-550 nm bands; it offers new opportunities for designing materials with potential applications in optoelectronic devices.

Skin cancers arising within tattoos: A systematic review

Background

Tattooing is a widespread practice and has increased in popularity over time. Many lesions have been described in relation to tattoos, including malignant tumors.

Objectives

The primary goal of this review is to determine whether the frequency of published cases of skin cancers within tattoos has been increasing over time.

Methods

Our review is in adherence to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines and reporting criteria. The databases MEDLINE via PubMed, Embase via Elsevier, and Scopus via Elsevier were searched from inception to February 23, 2023. No data or publication date limits were imposed.

Results

Our review identified 160 cases of cutaneous tumors arising within tattoos. An increase in published cases over time was observed. Most reported tumors developed within red tattoo pigment (36.9%), with the largest contribution by squamous cell carcinoma and keratoacanthoma lesions.

Limitations

There was a lack of consistency of information in published case reports which limited the scope of our analysis. Small sample size was also a limitation of this review.

Conclusions

With the increased popularity of tattoos, it is helpful to continue reporting cases of cutaneous malignancies within tattoos. Awareness of the frequency and severity of tumors within tattoos may be communicated to the public.

DNA lesions that block transcription induce the death of Trypanosoma cruzi via ATR activation, which is dependent on the presence of R-loops

Trypanosoma cruzi is the etiological agent of Chagas disease and a peculiar eukaryote with unique biological characteristics. DNA damage can block RNA polymerase, activating transcription-coupled nucleotide excision repair (TC-NER), a DNA repair pathway specialized in lesions that compromise transcription. If transcriptional stress is unresolved, arrested RNA polymerase can activate programmed cell death. Nonetheless, how this parasite modulates these processes is unknown. Here, we demonstrate that T. cruzi cell death after UV irradiation, a genotoxic agent that generates lesions resolved by TC-NER, depends on active transcription and is signaled mainly by an apoptotic-like pathway. Pre-treated parasites with α-amanitin, a selective RNA polymerase II inhibitor, become resistant to such cell death. Similarly, the gamma pre-irradiated cells are more resistant to UV when the transcription processes are absent. The Cockayne Syndrome B protein (CSB) recognizes blocked RNA polymerase and can initiate TC-NER. Curiously, CSB overexpression increases parasites' cell death shortly after UV exposure. On the other hand, at the same time after irradiation, the single-knockout CSB cells show resistance to the same treatment. UV-induced fast death is signalized by the exposition of phosphatidylserine to the outer layer of the membrane, indicating a cell death mainly by an apoptotic-like pathway. Furthermore, such death is suppressed in WT parasites pre-treated with inhibitors of ataxia telangiectasia and Rad3-related (ATR), a key DDR kinase. Signaling for UV radiation death may be related to R-loops since the overexpression of genes associated with the resolution of these structures suppress it. Together, results suggest that transcription blockage triggered by UV radiation activates an ATR-dependent apoptosis-like mechanism in T. cruzi, with the participation of CSB protein in this process.

Influence of Cu L-Histidinate Schiff Base Derivatives on Structural Features of Irradiated Rat's DNA

A study of rats liver DNA damages under the influence of X-ray radiation at a dose of 6.5 Gy(LD60) was carried out. The radioprotective properties of newly synthesized Cu(II) L-Schiff Histidinate complexes were also studied. The survival of rats was determined over a 30-day period after exposure to X-rays without pretreatment and also after preadministration of Cu(II) L-Histidinate-Schiff base complexes. The structural defects of rat's liver DNA were detected at 3, 7, 14, and 30 days post-irradiation extracted. The results obtained revealed that irradiation with a 6.5Gy dose in the control group degraded the characteristics of rat liver DNA in comparison to healthy DNA. On all investigated experimental days, a decrease in the melting temperature (Tm), a widening of the melting interval (ΔT), and a decrease in hypochromicity (Δh) were observed in the DNA samples of irradiated animals compared to the norm. The rat's pretreatment by Cu(II) L-Histidinate complexes 1 or 24 hours prior to irradiation improved DNA characteristics. Electrophoretic studies of DNA were in good agreement with the melting data. Based on the study results, it can be concluded that Cu(II) L-Histidinate complexes exhibit radioprotective properties under the studied conditions and can protect DNA from damage.

Ultraviolet attenuates centromere-mediated meiotic genome stability and alters gametophytic ploidy consistency in flowering plants

Ultraviolet (UV) radiation influences development and genome stability in organisms; however, its impact on meiosis, a special cell division essential for the delivery of genetic information across generations in eukaryotes, has not yet been elucidated. In this study, by performing cytogenetic studies, we reported that UV radiation does not damage meiotic chromosome integrity but attenuates centromere-mediated chromosome stability and induces unreduced gametes in Arabidopsis thaliana. We showed that functional centromere-specific histone 3 (CENH3) is required for obligate crossover formation and plays a role in the protection of sister chromatid cohesion under UV stress. Moreover, we found that UV specifically alters the orientation and organization of spindles and phragmoplasts at meiosis II, resulting in meiotic restitution and unreduced gametes. We determined that UV-induced meiotic restitution does not rely on the UV Resistance Locus8-mediated UV perception and the Tapetal Development and Function1- and Aborted Microspores-dependent tapetum development, but possibly occurs via altered JASON function and downregulated Parallel Spindle1. This study provides evidence that UV radiation influences meiotic genome stability and gametophytic ploidy consistency in flowering plants.

Spectroscopic analysis of bacterial photoreactivation

With the rise of bacterial infections and antibiotic resistance, spectroscopic devices originally developed for bacterial detection have shown promise to rapidly identify bacterial strains and determine the ratio of live to dead bacteria. However, the detection of the photoreactivated pathogens remains a critical concern. This study utilizes fluorescence and Raman spectroscopy to analyze bacterial responses to UV irradiation and subsequent photoreactivation. Our experimental results reveal limitations in fluorescence spectroscopy for detecting photoreactivated bacteria, as the intense fluorescence of tryptophan and tyrosine amino acids masks the fluorescence emitted by thymine molecules. Conversely, Raman spectroscopy proves more effective, showing a detectable decrease in band intensities of E. coli bacteria at 1248 and 1665 cm-1 after exposure to UVC radiation. Subsequent UVA irradiation results in the partial restoration of these band intensities, indicating DNA repair and bacterial photoreactivation. This enhanced understanding aims to improve the accuracy and effectiveness of these spectroscopic tools in clinical and environmental settings.

Fabrication of cyborg bacterial cells as living cell-material hybrids using intracellular hydrogelation

The production of living therapeutics, cell-based delivery of drugs and gene-editing tools and the manufacturing of bio-commodities all share a common concept: they use either a synthetic or a living cell chassis to achieve their primary engineering or therapeutic goal. Live-cell chassis face limitations inherent to their auto-replicative nature and the complexity of the cellular context. This limitation highlights the need for a new chassis combining the engineering simplicity of synthetic materials and the functionalities of natural cells. Here, we describe a protocol to assemble a synthetic polymeric network inside bacterial cells, rendering them incapable of cell division and allowing them to resist environmental stressors such as high pH, hydrogen peroxide and cell-wall-targeting antibiotics that would otherwise kill unmodified bacteria. This cellular bioengineering protocol details how bacteria can be transformed into single-lifespan devices that are resistant to environmental stressors and possess programable functionality. We designate the modified bacteria as cyborg bacterial cells. This protocol expands the synthetic biology toolset, conferring precise control over living cells and creating a versatile cell chassis for biotechnology, biomedical engineering and living therapeutics. The protocol, including the preparation of gelation reagents and chassis strain, can be completed in 4 d. The implementation of the protocol requires expertise in microbiology techniques, hydrogel chemistry, fluorescence microscopy and flow cytometry. Further functionalization of the cyborg bacterial cells and adaptation of the protocol requires skills ranging from synthetic genetic circuit engineering to hydrogel polymerization chemistries.

UV-B Stress-Triggered Amino Acid Reprogramming and ABA-Mediated Hormonal Crosstalk in Rhododendron chrysanthum Pall

Increased UV-B radiation due to ozone depletion adversely affects plants. This study focused on the metabolite dynamics of Rhododendron chrysanthum Pall. (R. chrysanthum) and the role of ABA in mitigating UV-B stress. Chlorophyll fluorescence metrics indicated that both JA and ABA increased UV-B resistance; however, the effect of JA was not as strong as that of ABA. Metabolomic analysis using UPLC-MS/MS (ultra-performance liquid chromatography and tandem mass spectrometry) revealed significant fluctuations in metabolites under UV-B and ABA application. UV-B decreased amino acids and increased phenolics, suggesting antioxidant defense activation. ABA treatment upregulated lipids and phenolic acids, highlighting its protective role. Multivariate analysis showed distinct metabolic clusters and pathways responding to UV-B and ABA, which impacted amino acid metabolism and hormone signal transduction. Exogenous ABA negatively regulated the JA signaling pathway in UV-B-exposed R. chrysanthum, as shown by KEGG enrichment. This study deepens understanding of plant stress-tolerance mechanisms and has implications for enhancing plant stress tolerance through metabolic and hormonal interventions.

The molecular mechanism of NF-κB dysregulation across different subtypes of renal cell carcinoma

BACKGROUND

The nuclear factor kappa B (NF-κB) is a critical pathway that regulates various cellular functions, including immune response, proliferation, growth, and apoptosis. Furthermore, this pathway is tightly regulated to ensure stability in the presence of immunogenic triggers or genotoxic stimuli. The lack of control of the NF-κB pathway can lead to the initiation of different diseases, mainly autoimmune diseases and cancer, including Renal cell carcinoma (RCC). RCC is the most common type of kidney cancer and is characterized by complex genetic composition and elusive molecular mechanisms.

AIM OF REVIEW

The current review summarizes the mechanism of NF-κB dysregulation in different subtypes of RCC and its impact on pathogenesis.

KEY SCIENTIFIC CONCEPT OF REVIEW

This review highlights the prominent role of NF-κB in RCC development and progression by driving the expression of multiple genes and interplaying with different pathways, including the phosphatidylinositol 3-kinase (PI3K)/protein kinase B (Akt) pathway. In silico analysis of RCC cohorts and molecular studies have revealed that multiple NF-κB members and target genes are dysregulated. The dysregulation includes receptors such as TLR2, signal-transmitting members including RelA, and target genes, for instance, HIF-1α. The lack of effective regulatory mechanisms results in a constitutively active NF-κB pathway, which promotes cancer growth, migration, and survival. In this review, we comprehensively summarize the role of dysregulated NF-κB-related genes in the most common subtypes of RCC, including clear cell RCC (ccRCC), chromophobe RCC (chRCC), and papillary RCC (PRCC).

Development of a Robust Saccharomyces cerevisiae Strain for Efficient Co-Fermentation of Mixed Sugars and Enhanced Inhibitor Tolerance through Protoplast Fusion

The economical and efficient commercial production of second-generation bioethanol requires fermentation microorganisms capable of entirely and rapidly utilizing all sugars in lignocellulosic hydrolysates. In this study, we developed a recombinant Saccharomyces cerevisiae strain, BLH510, through protoplast fusion and metabolic engineering to enhance its ability to co-ferment glucose, xylose, cellobiose, and xylooligosaccharides while tolerating various inhibitors commonly found in lignocellulosic hydrolysates. The parental strains, LF1 and BLN26, were selected for their superior glucose/xylose co-fermentation capabilities and inhibitor tolerance, respectively. The fusion strain BLH510 demonstrated efficient utilization of mixed sugars and high ethanol yield under oxygen-limited conditions. Under low inoculum conditions, strain BLH510 could completely consume all four kinds of sugars in the medium within 84 h. The fermentation produced 33.96 g/L ethanol, achieving 84.3% of the theoretical ethanol yield. Despite the challenging presence of mixed inhibitors, BLH510 successfully metabolized all four sugars above after 120 h of fermentation, producing approximately 30 g/L ethanol and reaching 83% of the theoretical yield. Also, strain BLH510 exhibited increased intracellular trehalose content, particularly under conditions with mixed inhibitors, where the intracellular trehalose reached 239.3 mg/g yeast biomass. This elevated trehalose content contributes to the enhanced stress tolerance of BLH510. The study also optimized conditions for protoplast preparation and fusion, balancing high preparation efficiency and satisfactory regeneration efficiency. The results indicate that BLH510 is a promising candidate for industrial second-generation bioethanol production from lignocellulosic biomass, offering improved performance under challenging fermentation conditions. Our work demonstrates the potential of combining protoplast fusion and metabolic engineering to develop superior S. cerevisiae strains for lignocellulosic bioethanol production. This approach can also be extended to develop robust microbial platforms for producing a wide array of lignocellulosic biomass-based biochemicals.

Application of UV LEDs to inactivate antibiotic resistant bacteria: Kinetics, efficiencies, and reactivations

Unregulated antibiotic use has led to the proliferation of antibiotic-resistant bacteria (ARB) in aquatic environments. Ultraviolet light-emitting diodes (UV LEDs) have evolved as an innovative technology for inactivating microorganisms offering several advantages over traditional mercury lamps. This research concentrated on utilizing UV LEDs with three distinct wavelengths (265 nm, 275 nm, and 285 nm) to inactivate E. coli DH10β encoding the ampicillin-resistant blaTEM-1 gene in its plasmid. Non-linear models, such as Geeraerd's and Weibull, provided more accurate characterization of the inactivation profiles than the traditional log-linear model due to the incorporation of both biological mechanisms and a deterministic approach within non-linear models. The inactivation rates of ARB were higher than antibiotic-sensitive bacteria (ASB) when subjected to UV LEDs. The highest inactivation rates were observed when all microorganisms were exposed to 265 nm. Photoreactivation emerged as the primary mechanism responsible for repairing DNA damage induced by UV LEDs. 285 nm showed the highest reactivation efficiencies for ARB under different fluences. At higher fluences, both 265 and 275 nm displayed similar effectiveness in suppressing reactivation, while at lower fluences, 275 nm exhibited better efficacies in controlling the reactivation. Therefore, the inhibition of reactivation was influenced by the extent of damage incurred to both DNA and enzymes. In nutrient-poor media (0.9 % NaCl), ASB did not exhibit any reactivation potential. However, the addition of Luria-Bertani (LB) broth promoted the reactivation of ASB. Lower fluence rate was more beneficial at 265 nm whereas higher fluence rates were more effective for longer wavelengths. The inactivation of ARB was enhanced by dissolved organic carbon (DOC) at low fluences. However, the removal of ARB was reduced due to the presence of DOC at higher fluences. The highest energy demand for ARB inactivation was reported at 285 nm. ENVIRONMENTAL IMPLICATION: The excessive and unregulated utilization of antibiotics has emerged as a significant issue for public health. This paper presents a comprehensive analysis of the effectiveness of UV LEDs, an emerging technology, in the inactivation of antibiotic-resistant bacteria (ARB). This research paper explores the kinetics of UV LEDs with different wavelengths to inactivate ARB along with the reactivation efficiencies. This research work also explores the impact and relevant mechanisms of the impact of dissolved organic carbon (DOC) on the inactivation of ARB by UV LEDs.

Induced genetic diversity through mutagenesis in wheat gene pool and significant use of SCoT markers to underpin key agronomic traits

BACKGROUND

This research explores the efficacy of mutagenesis, specifically using sodium azide (SA) and hydrazine hydrate (HZ) treatments, to introduce genetic diversity and enhance traits in three wheat (Triticum aestivum L.) genotypes. The experiment entails subjecting the seeds to different doses of SA and HZ and cultivating them in the field for two consecutive generations: M1 (first generation) and M2 (second generation). We then employed selective breeding techniques with Start Codon Targeted (SCoT) markers to select traits within the wheat gene pool. Also, the correlation between SCoT markers and specific agronomic traits provides insights into the genetic mechanisms underlying mutagenesis-induced changes in wheat.

RESULTS

In the study, eleven genotypes were derived from parent varieties Sids1, Sids12, and Giza 168, and eight mutant genotypes were selected from the M1 generation and further cultivated to establish the M2 generation. The results revealed that various morphological and agronomical characteristics, such as plant height, spikes per plant, spike length, spikelet per spike, grains per spikelet, and 100-grain weight, showed increases in different genotypes from M1 to M2. SCoT markers were employed to assess genetic diversity among the eleven genotypes. The bioinformatics analysis identified a correlation between SCoT markers and the transcription factors ABSCISIC ACID INSENSITIVE3 (ABI3) and VIVIPAROUS1 (VP1), crucial for plant development, growth, and stress adaptation. A comprehensive examination of genetic distance and the function identification of gene-associated SCoT markers may provide valuable insights into the mechanisms by which SA and HZ act as mutagens, enhancing wheat agronomic qualities.

CONCLUSIONS

This study demonstrates the effective use of SA and HZ treatments to induce gene diversity through mutagenesis in the wheat gene pool, resulting in the enhancement of agronomic traits, as revealed by SCoT markers. The significant improvements in morphological and agronomical characteristics highlight the potential of mutagenesis techniques for crop improvement. These findings offer valuable information for breeders to develop effective breeding programs to enhance wheat quality and resilience through increased genetic diversity.

From bedside to genetic analysis: New insights into pathophysiology of melanoma, basal cell carcinoma, and other cancers

OBJECTIVE

Patients with myotonic muscular dystrophy (MMD) were observed to have numerous basal cell carcinoma (BCC) and abnormal dysplastic nevi (DN) on non-sun exposed skin. Simultaneously a large study published in the Journal of American Medical Association (JAMA) illustrated that patients with MMD have "overall" an increased risk for cancer development. Based on these findings, this author in 2010 postulated that dysregulation of RNA binding proteins (RBP), responsible for clinical manifestations of MMD, is also responsible for the development of BCC and melanoma.

METHODS

To report new research elucidating the etiology of melanoma, BCC, MMD-induced cancers, and potentially other environmentally induced malignancies.

RESULTS

Dysregulation of RBP induces aberrant mRNA splicing; recent data indicates that abnormal mRNA splicing not just plays a key role in the pathogenesis of melanoma but is a hallmark of essentially all human malignancies.

CONCLUSION

The author's hypothesis is that ultraviolet (UV) radiation induces DNA damage in intronic regions of a variety of genes. Furthermore, these UV-induced abnormal DNA dimers, repeats and mutations interfere with normal mRNA splicing thus producing abnormal proteins. These abnormal proteins in turn activate oncogenic pathways such as hedgehog, MAP kinase, and WNT.

5-aminolevulinic acid photodynamic therapy protects against UVB-induced skin photoaging: A DNA-repairing mechanism involving the BER signalling pathway

Low-dose 5-aminolevulinic acid photodynamic therapy (ALA-PDT) has been used to cope with skin photoaging, and is thought to involve DNA damage repair responses. However, it is still unknown how low-dose ALA-PDT regulates DNA damage repair to curb skin photoaging. We established a photoaging model using human dermal fibroblasts (HDFs) and rat skin. RNA-sequencing (RNA-seq) analysis was conducted to identify differentially expressed genes (DEGs) in HDFs before and after low-dose ALA-PDT treatment, followed by bioinformatics analysis. Senescence-associated β-galactosidase (SA-β-gal) staining was employed to assess skin aging-related manifestations and Western blotting to evaluate the expression of associated proteins. A comet assay was used to detect cellular DNA damage, while immunofluorescence to examine the expression of 8-hydroxy-2'-deoxyguanosine (8-oxo-dG) in cells and skin tissues. In both in vivo and in vitro models, low-dose ALA-PDT alleviated the manifestations of ultraviolet B (UVB)-induced skin photoaging. Low-dose ALA-PDT significantly reduced DNA damage in photoaged HDFs. Furthermore, low-dose ALA-PDT accelerated the clearance of the photoproduct 8-oxo-dG in photoaged HDFs and superficial dermis of photoaged rat skin. RNA-seq analysis suggested that low-dose ALA-PDT upregulated the expression of key genes in the base excision repair (BER) pathway. Further functional validation showed that inhibition on BER expression by using UPF1069 significantly suppressed SA-β-gal activity, G2/M phase ratio, expression of aging-associated proteins P16, P21, P53, and MUTYH proteins, as well as clearance of the photoproduct 8-oxo-dG in photoaged HDFs. Low-dose ALA-PDT exerts anti-photoaging effects by activating the BER signalling pathway.

Light Sensing beyond Vision: Focusing on a Possible Role for the FICZ/AhR Complex in Skin Optotransduction

Although our skin is not the primary visual organ in humans, it acts as a light sensor, playing a significant role in maintaining our health and overall well-being. Thanks to the presence of a complex and sophisticated optotransduction system, the skin interacts with the visible part of the electromagnetic spectrum and with ultraviolet (UV) radiation. Following a brief overview describing the main photosensitive molecules that detect specific electromagnetic radiation and their associated cell pathways, we analyze their impact on physiological functions such as melanogenesis, immune response, circadian rhythms, and mood regulation. In this paper, we focus on 6-formylindolo[3,2-b]carbazole (FICZ), a photo oxidation derivative of the essential amino acid tryptophan (Trp). This molecule is the best endogenous agonist of the Aryl hydrocarbon Receptor (AhR), an evolutionarily conserved transcription factor, traditionally recognized as a signal transducer of both exogenous and endogenous chemical signals. Increasing evidence indicates that AhR is also involved in light sensing within the skin, primarily due to its ligand FICZ, which acts as both a chromophore and a photosensitizer. The biochemical reactions triggered by their interaction impact diverse functions and convey crucial data to our body, thus adding a piece to the complex puzzle of pathways that allow us to decode and elaborate environmental stimuli.

The photo-protective role of vitamin D in the microalga Emiliania huxleyi

An essential interaction between sunlight and eukaryotes involves vitamin D production through exposure to ultraviolet (UV) radiation. While extensively studied in vertebrates, the role of vitamin D in non-animal eukaryotes like microalgae remains unclear. Here, we investigate the potential involvement of vitamin D in the UV-triggered response of Emiliania huxleyi, a microalga inhabiting shallow ocean depths that are exposed to UV. Our results show that E. huxleyi produces vitamin D2 and D3 in response to UV. We further demonstrate that E. huxleyi responds to external administration of vitamin D at the transcriptional level, regulating protective mechanisms that are also responsive to UV. Our data reveal that vitamin D addition enhances algal photosynthetic performance while reducing harmful reactive oxygen species buildup. This study contributes to understanding the function of vitamin D in E. huxleyi and its role in non-animal eukaryotes, as well as its potential importance in marine ecosystems.

Optimizing the Extraction of Bioactive Compounds from Porphyra linearis (Rhodophyta): Evaluating Alkaline and Enzymatic Hydrolysis for Nutraceutical Applications

Porphyra sensu lato is one of the most economically significant and widely cultured and consumed algae in the world. Porphyra species present excellent nutraceutic properties due to their bioactive compounds (BACs). This research aimed to find the most efficient aqueous extraction method for BACs by examining alkaline and enzymatic hydrolysis. Alkaline hydrolysis with 2.5% sodium carbonate (SC) and at 80 °C proved optimal for extracting all BACs (phycobiliproteins, soluble proteins, polyphenols, and carbohydrates) except mycosporine-like amino acids (MAAs), which were best extracted with water only, and at 80 °C. Enzymatic hydrolysis, particularly with the 'Miura' enzymatic cocktail (cellulase, xylanase, glycoside hydrolase, and β-glucanase), showed superior results in extracting phycoerythrin (PE), phycocyanin (PC), soluble proteins, and carbohydrates, with increases of approximately 195%, 510%, 890%, and 65%, respectively, compared to the best alkaline hydrolysis extraction (2.5% SC and 80 °C). Phenolic content analysis showed no significant difference between the 'Miura' cocktail and 2.5% SC treatments. Antioxidant activity was higher in samples from alkaline hydrolysis, while extraction of MAAs showed no significant difference between water-only and 'Miura' treatments. The study concludes that enzymatic hydrolysis improves the efficiency of BACs extraction in P. linearis, highlighting its potential for the nutraceutical industry, and especially with respect to MAAs for topical and oral UV-photoprotectors.

Cyclopropanation and membrane unsaturation improve antibiotic resistance of swarmer Pseudomonas and its sod mutants exposed to radiations, in vitro and in silico approch

It was known that UVc irradiation increases the reactive oxygen species' (ROS) levels in bacteria hence the intervention of antioxidant enzymes and causes also changes in fatty acids (FAs) composition enabling bacteria to face antibiotics. Here, we intended to elucidate an interrelationship between SOD and susceptibility to antibiotics by studying FA membrane composition of UVc-treated P. aeruginosa PAO1 and its isogenic mutants (sodM, sodB and sod MB) membrane, after treatment with antibiotics. Swarmer mutants defective in genes encoding superoxide dismutase were pre-exposed to UVc radiations and then tested by disk diffusion method for their contribution to antibiotic tolerance in comparison with the P. aeruginosa wild type (WT). Moreover, fatty acid composition of untreated and UVc-treated WT and sod mutants was examined by Gaz chromatography and correlated to antibiotic resistance. Firstly, it has been demonstrated that after UVc exposure, swarmer WT strain, sodM and sodB mutants remain resistant to polymixin B, a membrane target antibiotic, through membrane unsaturation supported by the intervention of Mn-SOD after short UVc exposure and cyclopropanation of unsaturated FAs supported by the action of Fe-SOD after longer UVc exposure. However, resistance for ciprofloxacin is correlated with increase in saturated FAs. This correlation has been confirmed by a molecular docking approach showing that biotin carboxylase, involved in the initial stage of FA biosynthesis, exhibits a high affinity for ciprofloxacin. This investigation has explored the correlation of antibiotic resistance with FA content of swarmer P.aeruginosa pre-exposed to UVc radiations, confirmed to be antibiotic target dependant.

Impact of double-strand breaks induced by uv radiation on neuroinflammation and neurodegenerative disorders

Exposure to UV affects the development and growth of a wide range of organisms. Nowadays, researchers are focusing on the impact of UV radiation and its underlying molecular mechanisms, as well as devising strategies to mitigate its harmful effects. Different forms of UV radiation, their typical exposure effects, the impact of UV on DNA integrity, and the deterioration of genetic material are discussed in this review; furthermore, we also review the effects of UV radiation that affect the biological functions of the organisms. Subsequently, we address the processes that aid organisms in navigating the damage in genetic material, neuroinflammation, and neurodegeneration brought on by UV-mediated double-strand breaks. To emphasize the molecular pathways, we conclude the review by going over the animal model studies that highlight the genes and proteins that are impacted by UV radiation.

Identification of a chaperone-code responsible for Rad51-mediated genome repair

Posttranslational modifications of Hsp90 are known to regulate its in vivo chaperone functions. Here, we demonstrate that the lysine acetylation-deacetylation dynamics of Hsp82 is a major determinant in DNA repair mediated by Rad51. We uncover that the deacetylated lysine 27 in Hsp82 dictates the formation of the Hsp82-Aha1-Rad51 complex, which is crucial for client maturation. Intriguingly, Aha1-Rad51 complex formation is not dependent on Hsp82 or its acetylation status; implying that Aha1-Rad51 association precedes the interaction with Hsp82. The DNA damage sensitivity of Hsp82 (K27Q/K27R) mutants are epistatic to the loss of the (de)acetylase hda1Δ; reinforcing the importance of the reversible acetylation of Hsp82 at the K27 position. These findings underscore the significance of the cross talk between a specific Hsp82 chaperone modification code and the cognate cochaperones in a client-specific manner. Given the pivotal role that Rad51 plays during DNA repair in eukaryotes and particularly in cancer cells, targeting the Hda1-Hsp90 axis could be explored as a new therapeutic approach against cancer.

DNA modifications: Biomarkers for the exposome?

The concept of the exposome is the encompassing of all the environmental exposures, both exogenous and endogenous, across the life course. Many, if not all, of these exposures can result in the generation of reactive species, and/or the modulation of cellular processes, that can lead to a breadth of modifications of DNA, the nature of which may be used to infer their origin. Because of their role in cell function, such modifications have been associated with various major human diseases, including cancer, and so their assessment is crucial. Historically, most methods have been able to only measure one or a few DNA modifications at a time, limiting the information available. With the development of DNA adductomics, which aims to determine the totality of DNA modifications, a far more comprehensive picture of the DNA adduct burden can be gained. Importantly, DNA adductomics can facilitate a "top-down" investigative approach whereby patterns of adducts may be used to trace and identify the originating exposure source. This, together with other 'omic approaches, represents a major tool for unraveling the complexities of the exposome and hence allow a better a understanding of the environmental origins of disease.

Kinetics of inactivation of bacteria responsible for infections in hospitals using UV-LED

Controlling the microbial load in the environment is crucial to prevent the spread of organisms. The continuous spread of nosocomial infections in hospital facilities and the emergence of the coronavirus (COVID-19) highlighted the importance of disinfection processes in health safety. This work aimed to evaluate the effectiveness of LED-based disinfection lamps on bacteria from the ESKAPEE group and virus phage in vitro inactivation to be applied in hospital environments and health facilities disinfection. This study evaluated the effect of different UV wavelengths (275 nm, 280 nm (UVC), 310 nm (UVB) and 340 nm (UVA)) on the disinfection process of various microbial indicators including E. coli, S. aureus, P. aeruginosa, B. subtilis and Bacteriophage lambda DSM 4499. Exposure time (5 min-30 min), exposure distance (0.25 m and 0.5 m) and surface materials (glass, steel, and polished wood) were evaluated on the disinfection efficiency. Furthermore, the study determined the recovery capacity of each species after UV damage. UVC-LED lamps could inactivate 99.99 % of microbial indicators after 20 min exposures at a 0.5 m distance. The exposure time needed to completely inactivate E. coli, S. aureus, P. aeruginosa, B. subtilis and Bacteriophage lambda DSM 4499 can be decreased by reducing the exposure distance. UVB-LED and UVA-LED lamps were not able to promote a log reduction of 4 and were not effective on B. subtilis or bacteriophage lambda DSM 4499 inactivation. Thus, only UVC-LED lamps were tested on the decontamination of different surface materials, which was successful. P. aeruginosa showed the ability to recover from UV damage, but its inactivation rate remains 99.99 %, and spores from B. subtilis were not completely inactivated. Nevertheless, the inactivation rate of these indicators remained at 99.99 % with 24 h incubation after UVC irradiation. UVC-LED lamps emitting 280 nm were the most indicated to disinfect surfaces from microorganisms usually found in hospital environments.

Optimized Ultraviolet-C Processing Inactivates Pathogenic and Spoilage-Associated Bacteria while Preserving Bioactive Proteins, Vitamins, and Lipids in Human Milk

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.

Destructive effects of UVC radiation on Drosophila melanogaster: Mortality, fertility, mutations, and molecular mechanisms

The detrimental effects of ultraviolet C (UVC) radiation on living organisms, with a specific focus on the fruit fly Drosophila melanogaster, were examined. This study investigated the impact of heightened UVC radiation exposure on D. melanogaster by assessing mortality and fertility rates, studying phenotypic mutations, and investigating the associated molecular mechanisms. The findings of this study revealed that UVC radiation increases mortality rates and decreases fertility rates in D. melanogaster. Additionally, phenotypic wing mutations were observed in the exposed flies. Furthermore, the study demonstrated that UVC radiation downregulates the expression of antioxidant genes, including superoxide dismutase (SOD), manganese-dependent superoxide dismutase (Mn-SOD), zinc-dependent superoxide dismutase (Cu-Zn-SOD), and the G protein-coupled receptor methuselah (MTH) gene. These results suggest that UVC radiation exerts a destructive effect on D. melanogaster by inducing oxidative stress, which is marked by the overexpression of harmful oxidative processes and a simultaneous reduction in antioxidant gene expression. In conclusion, this study underscores the critical importance of comprehending the deleterious effects of UVC radiation, not only to safeguard human health on Earth, but also to address the potential risks associated with space missions, such as the ongoing Emirate astronaut program.

Photodissociation of leucine-enkephalin protonated peptide: an experimental and theoretical perspective

Understanding the competing processes that govern far ultraviolet photodissociation (FUV-PD) of biopolymers such as proteins is a challenge. Here, we report a combined experimental and theoretical investigation of FUV-PD of protonated leucine-enkephalin pentapeptide ([YGGFL + H]+) in the gas-phase. Time-dependent density functional theory (TD-DFT) calculations in combination with experiments and previous results for amino acids and shorter peptides help in rationalizing the evolution of the excited states. The results confirm that fragmentation of [YGGFL + H]+ results mainly from vibrationally excited species in the ground electronic state, populated after internal conversion. We also propose fragmentation mechanisms for specific photo-fragments such as tyrosine side chain loss (with an extra hydrogen) or hydrogen loss. In general, we observe the same mechanisms as for smaller peptides or protonated Tyr and Phe, that are not quenched by the presence of other amino acids. Nevertheless, we also found some differences, as for H loss, in part due to the fact that the charge is solvated by the peptide chain and not only by the COOH terminal group.

Suppression of photoreactivation of E. coli by excimer far-UV light (222 nm) via damage to multiple targets

Low-pressure mercury lamps emitting at 254 nm (UV254) are used widely for disinfection. However, subsequent exposure to visible light results in photoreactivation of treated bacteria. This study employed a krypton chloride excimer lamp emitting at 222 nm (UV222) to inactivate E. coli. UV222 and UV254 treatment had similar E. coli-inactivation kinetics. Upon subsequent irradiation with visible light, E. coli inactivated by UV254 was reactivated from 2.71-log to 4.75-log, whereas E. coli inactivated by UV222 showed negligible photoreactivation. UV222 treatment irreversibly broke DNA strands in the bacterium, whereas UV254 treatment primarily formed nucleobase dimers. Additionally, UV222 treatment caused cell membrane damage, resulting in wizened, pitted cells and permeability changes. The damage to the cell membrane was mainly due to the photolysis of proteins and lipids by UV222. Furthermore, the photolysis of proteins by UV222 destroyed enzymes, which blocked photoreactivation and dark repair. The multiple damages can be further evidenced by 4.0-61.1 times higher quantum yield in the photolysis of nucleobases and amino acids for UV222 than UV254. This study demonstrates that UV222 treatment damages multiple sites in bacteria, leading to their inactivation. Employing UV222 treatment as an alternative to UV254 could be viable for inhibiting microorganism photoreactivation in water and wastewater.

The Role of Nitrate Supply in Bioactive Compound Synthesis and Antioxidant Activity in the Cultivation of Porphyra linearis (Rhodophyta, Bangiales) for Future Cosmeceutical and Bioremediation Applications

Porphyra sensu lato has economic importance for food and pharmaceutical industries due to its significant physiological activities resulting from its bioactive compounds (BACs). This study aimed to determine the optimal nitrate dosage required in short-term cultivation to achieve substantial BAC production. A nitrate experiment using varied concentrations (0 to 6.5 mM) revealed optimal nitrate uptake at 0.5 mM in the first two days and at 3 and 5 mM in the last five days. Polyphenols and carbohydrates showed no differences between treatments, while soluble proteins peaked at 1.5 and 3 mM. Total mycosporine-like amino acids (MAAs) were highest in algae incubated at 5 and 6.5 mM, and the highest antioxidant activity was observed in the 5 mM, potentially related to the MAAs amount. Total carbon and sulfur did not differ between treatments, while nitrogen decreased at higher nitrate. This discovery highlights the nuanced role of nitrate in algal physiology, suggesting that biological and chemical responses to nitrate supplementation can optimize an organism's health and its commercially significant bioactive potential. Furthermore, given its ability to absorb high doses of nitrate, this alga can be cultivated in eutrophic zones or even in out-/indoor tanks, becoming an excellent option for integrated multi-trophic aquaculture (IMTA) and bioremediation.

MLKL, a new actor of UVB-induced apoptosis in human diploid dermal fibroblasts

Ultraviolet radiation (UVR) is a major environmental mutagen. In skin, UVR can initiate cancer through the induction of mutagenic DNA damage and promote its progression. An important cancer prevention mechanism is the regulated cell death (RCD), which can safely dispose of damaged cells. Apoptosis, a well-known RCD, is known to be activated by UVR, but part of the mechanism and proteins involved in UVR-induced apoptosis are still to be discovered. Receptor-interacting serine/threonine-protein kinase 3 (RIPK3) and mixed lineage kinase domain-like (MLKL) are two proteins involved in necroptosis, a form of RCD. Here, we have evaluated the implication of RIPK3 and MLKL in UVB-induced cell death in human diploid dermal fibroblasts. Our results show that RIPK3 and MLKL play opposite roles in UVB-induced cell death, in a necroptosis independent pathway. We showed that RIPK3 protects cells from UVB cell death, while MLKL sensitizes cells to UVB-induced apoptosis. Taken together these results are the first to show the implication of RIPK3 and MLKL in survival and apoptosis, respectively, bringing two new actors in UVB-induced cell death pathway.

Limited contribution of photoenzymatic DNA repair in mitigating carry-over effects from larval UVB exposure: Implications for frog recruitment

Solar ultraviolet-B (UVB) radiation has increased due to stratospheric ozone depletion, climate and ecosystem changes and is a driver of amphibian population declines. Photoenzymatic repair (PER) is a critical mechanism for limiting UVB lethality in amphibian larvae. However, the link between PER and the UVB-induced effects remains understudied through long-term investigations in vivo. Here, we assessed how larval PER determines the lethal and sublethal effects induced by environmentally relevant acute UVB exposure until the juvenile phase in the Neotropical frog Odontophrynus americanus. We conducted laboratory-based controlled experiments in which tadpoles were or were not exposed to UVB and subsequently were exposed to light (for PER activation) or dark treatments. Results showed that the rates of mortality and apoptosis observed in post-UVB dark treatment are effectively limited in post-UVB light treatment, indicating PER (and not dark repair, i.e. nucleotide excision repair) is critical to limit the immediate genotoxic impact of UVB-induced pyrimidine dimers. Nonetheless, even tadpoles that survived UVB exposure using PER showed sublethal complications that extended to the juvenile phase. Tadpole responses included alterations in morphology, chromosomal instability, increased skin susceptibility to fungal proliferation, as well as increased generation of reactive oxygen species. The short-term effects were carried over to later stages of life because metamorphosis time increased and juveniles were smaller. No body abnormalities were visualized in tadpoles, metamorphs, and juveniles, suggesting that O. americanus is UVB-resistant concerning these responses. This study reveals that even frog species equipped with an effective PER are not immune to carry-over effects from early UVB exposure, which are of great ecological relevance as late metamorphosis and smaller juveniles may impact individual performance and adult recruitment to breeding. Future ecological risk assessments and conservation and management efforts for amphibian species should exercise caution when linking PER effectiveness to UVB resistance.

Germicidal lamps using UV-C radiation may pose health safety issues: a biomolecular analysis of their effects on apoptosis and senescence

The battle against the COVID-19 pandemic has spurred a heightened state of vigilance in global healthcare, leading to the proliferation of diverse sanitization methods. Among these approaches, germicidal lamps utilizing ultraviolet (UV) rays, particularly UV-C (wavelength ranging from 280 to 100 nm), have gained prominence for domestic use. These light-emitting diode (LED) lamps are designed to sanitize the air, objects, and surfaces. However, the prevailing concern is that these UV lamps are often introduced into the market without adequate accompanying information to ensure their safe utilization. Importantly, exposure to absorbed UV light can potentially trigger adverse biological responses, encompassing cell death and senescence. Our research encompassed a series of investigations aimed at comprehending the biological repercussions of UV-C radiation exposure from readily available domestic lamps. Our focus centered on epithelial retinal cells, keratinocytes, and fibroblasts, components of the skin and ocular targets frequently exposed to UV irradiation. Our findings underscore the potential harm associated with even brief exposure to UV, leading to irreversible and detrimental alterations in both skin cells and retinal cells of the eye. Notably, epithelial retinal cells exhibited heightened sensitivity, marked by substantial apoptosis. In contrast, keratinocytes demonstrated resilience to apoptosis even at elevated UV doses, though they were prone to senescence. Meanwhile, fibroblasts displayed a gradual amplification of both senescence and apoptosis as radiation doses escalated. In summary, despite the potential benefits offered by UV-C in deactivating pathogens like SARS-CoV-2, it remains evident that the concurrent risks posed by UV-C to human health cannot be ignored.

Extreme ultraviolet time-resolved photoelectron spectroscopy of adenine, adenosine and adenosine monophosphate in a liquid flat jet

Time-resolved photoelectron spectroscopy using an extreme-ultraviolet (XUV) probe pulse was used to investigate the UV photoinduced dynamics of adenine (Ade), adenosine (Ado), and adenosine-5-monophosphate (AMP) in a liquid water jet. In contrast to previous studies using UV probe pulses, the XUV pulse at 21.7 eV can photoionize all excited states of a molecule, allowing for full relaxation pathways to be addressed after excitation at 4.66 eV. This work was carried out using a gas-dynamic flat liquid jet, resulting in considerably enhanced signal compared to a cylindrical jet. All three species decay on multiple time scales that are assigned based on their decay associated spectra; the fastest decay of ∼100 fs is assigned to ππ* decay to the ground state, while a smaller component with a lifetime of ∼500 fs is attributed to the nπ* state. An additional slower channel in Ade is assigned to the 7H Ade conformer, as seen previously. This work demonstrates the capability of XUV-TRPES to disentangle non-adiabatic dynamics in an aqueous solution in a state-specific manner and represents the first identification of the nπ* state in the relaxation dynamics of adenine and its derivatives.

Exploring the role of impedance spectroscopy in assessing 405 nm laser-induced inactivation of saccharomyces cerevisiae

Impedance spectroscopy was employed to assess the electrical properties of yeast following 405 nm laser irradiation, exploring the effects of visible, non-ionizing laser-induced inactivation as a more selective and safer alternative for photoinactivation applications compared to the use of DNA targeting, ionizing UV light. Capacitance and impedance spectra were obtained for yeast suspensions irradiated for 10, 20, 30, and 40 min using 100 and 200 mW laser powers. Noticeable differences in capacitance spectra were observed at lower frequencies (40 Hz to 1 kHz), with a significant increase at 40 min for both laser powers. β-dispersion was evident in the impedance spectra in the frequency range of 10 kHz to 10 MHz. The characteristic frequency of dielectric relaxation steadily shifted to higher frequencies with increasing irradiation time, with a drastic change observed at 40 min for both laser powers. These changes signify a distinct alteration in the physical state of yeast. A yeast spot assay demonstrated a decrease in cell viability with increasing laser irradiation dose. The results indicate a correlation between changes in electrical properties, cell viability, and the efficacy of 405 nm laser-induced inactivation. Impedance spectroscopy is shown to be an efficient, non-destructive, label-free method for monitoring changes in cell viability in photobiological effect studies. The development of impedance spectroscopy-based real-time studies in photoinactivation holds promise for advancing our understanding of light-cell interactions in medical applications.

The effect of common paralytic agents used for fluorescence imaging on redox tone and ATP levels in Caenorhabditis elegans

One aspect of Caenorhabditis elegans that makes it a highly valuable model organism is the ease of use of in vivo genetic reporters, facilitated by its transparent cuticle and highly tractable genetics. Despite the rapid advancement of these technologies, worms must be paralyzed for most imaging applications, and few investigations have characterized the impacts of common chemical anesthetic methods on the parameters measured, in particular biochemical measurements such as cellular energetics and redox tone. Using two dynamic reporters, QUEEN-2m for relative ATP levels and reduction-oxidation sensitive GFP (roGFP) for redox tone, we assess the impact of commonly used chemical paralytics. We report that no chemical anesthetic is entirely effective at doses required for full paralysis without altering redox tone or ATP levels, and that anesthetic use alters the detected outcome of rotenone exposure on relative ATP levels and redox tone. We also assess the use of cold shock, commonly used in combination with physical restraint methods, and find that cold shock does not alter either ATP levels or redox tone. In addition to informing which paralytics are most appropriate for research in these topics, we highlight the need for tailoring the use of anesthetics to different endpoints and experimental questions. Further, we reinforce the need for developing less disruptive paralytic methods for optimal imaging of dynamic in vivo reporters.

Ultraviolet C inactivation of Coxiella burnetii for production of a structurally preserved whole cell vaccine antigen

Q fever, a worldwide-occurring zoonotic disease, can cause economic losses for public and veterinary health systems. Vaccines are not yet available worldwide and currently under development. In this regard, it is important to produce a whole cell antigen, with preserved structural and antigenic properties and free of chemical modifications. Thus, inactivation of Coxiella burnetii with ultraviolet light C (UVC) was evaluated. C. burnetii Nine Mile phase I (NMI) and phase II (NMII) were exposed to decreasing intensities in a time-dependent manner and viability was tested by rescue cultivation in axenic medium or cell culture. Effects on the cell structure were visualized by transmission electron microscopy and antigenicity of UVC-treated NMI was studied by immunization of rabbits. NMI and NMII were inactivated at UVC intensities of 250 µW/cm2 for 5 min or 100 µW/cm2 for 20 min. Reactivation by DNA repair was considered to be unlikely. No morphological changes were observed directly after UVC inactivation by transmission electron microscopy, but severe swelling and membrane degradation of bacteria with increasing severity occurred after 24 and 48 h. Immunization of rabbits resulted in a pronounced antibody response. UVC inactivation of C. burnetii resulted in a structural preserved, safe whole cell antigen and might be useful as antigen for diagnostic purposes or as vaccine candidate.

Comparative Metabolomics and Transcriptome Studies of Two Forms of Rhododendron chrysanthum Pall. under UV-B Stress

Rhododendron chrysanthum Pall. (R. chrysanthum), a plant with UV-B resistance mechanisms that can adapt to alpine environments, has gained attention as an important plant resource with the ability to cope with UV-B stress. In this experiment, R. chrysanthums derived from the same origin were migrated to different culture environments (artificial climate chamber and intelligent artificial incubator) to obtain two forms of R. chrysanthum. After UV-B irradiation, 404 metabolites and 93,034 unigenes were detected. Twenty-six of these different metabolites were classified as UV-B-responsive metabolites. Glyceric acid is used as a potential UV-B stress biomarker. The domesticated Rhododendron chrysanthum Pall. had high amino acid and SOD contents. The study shows that the domesticated Rhododendron chrysanthum Pall. has significant UV-B resistance. The transcriptomics results show that the trends of DEGs after UV-B radiation were similar for both forms of R. chrysanthum: cellular process and metabolic process accounted for a higher proportion in biological processes, cellular anatomical entity accounted for the highest proportion in the cellular component, and catalytic activity and binding accounted for the highest proportion in the molecular function category. Through comparative study, the forms of metabolites resistant to UV-B stress in plants can be reflected, and UV-B radiation absorption complexes can be screened for application in future specific practices. Moreover, by comparing the differences in response to UV-B stress between the two forms of R. chrysanthum, references can be provided for cultivating domesticated plants with UV-B stress resistance characteristics. Research on the complex mechanism of plant adaptation to UV-B will be aided by these results.

Tyrosine 1-phosphorylated RNA polymerase II transcribes PROMPTs to facilitate proximal promoter pausing and induce global transcriptional repression in response to DNA damage

DNA damage triggers a complex transcriptional response that involves both activation and repression of gene expression. In this study, we investigated global changes in transcription in response to ionizing irradiation (IR), which induces double-strand breaks in DNA. We used mNET-seq to profile nascent transcripts bound to different phosphorylated forms of the RNA polymerase II (RNA Pol II) C-terminal domain (CTD). We found that IR leads to global transcriptional repression of protein-coding genes, accompanied by an increase in antisense transcripts near promoters, called PROMPTs, transcribed by RNA Pol II phosphorylated on tyrosine 1 (Y1P) residue of the CTD. These Y1P-transcribed PROMPTs are enriched for PRC2 binding sites and associated with RNA Pol II proximal promoter pausing. We show the interaction between Y1P RNA Pol II and PRC2, as well as PRC2 binding to PROMPTs. Inhibition of PROMPTs or depletion of PRC2 leads to loss of transcriptional repression. Our results reveal a novel function of Y1P-dependent PROMPTs in mediating PRC2 recruitment to chromatin and RNA Pol II promoter pausing in response to DNA damage.

An evaluation of conventional and nature-based technologies for controlling antibiotic-resistant bacteria and antibiotic-resistant genes in wastewater treatment plants

Antibiotic resistance is a globally recognized health concern which leads to longer hospital stays, increased morbidity, increased mortality, and higher medical costs. Understanding how antibiotic resistance persists and exchanges in environmental systems like soil, water, and wastewater are critically important for understanding the emergence of pathogens with new resistance profiles and the subsequent exposure of people who indirectly/directly come in contact with these pathogens. There are concerns about the widespread application of prophylactic antibiotics in the clinical and agriculture sectors, as well as chemicals/detergents used in food and manufacturing industries, especially the quaternary ammonium compounds which have been found responsible for the generation of resistant genes in water and soil. The rates of horizontal gene transfer increase where there is a lack of proper water/wastewater infrastructure, high antibiotic manufacturing industries, or endpoint users - such as hospitals and intensive agriculture. Conventional wastewater treatment technologies are often inefficient in the reduction of ARB/ARGs and provide the perfect combination of conditions for the development of antibiotic resistance. The wastewater discharged from municipal facilities may therefore be enriched with bacterial communities/pathogens and provide a suitable environment (due to the presence of nutrients and other pollutants) to enhance the transfer of antibiotic resistance. However, facilities with tertiary treatment (either traditional/emerging technologies) provide higher rates of reduction. This review provides a synthesis of the current understanding of wastewater treatment and antibiotic resistance, examining the drivers that may accelerate their possible transmission to a different environment, and highlighting the need for tertiary technologies used in treatment plants for the reduction of resistant bacteria/genes.