ROS-mediated killing efficiency with visible light of bacteria carrying different red fluorochrome proteins

Involvement of Nucleotide Excision Repair and Rec-Dependent Pathway Genes for UV Radiation Resistance in Deinococcus irradiatisoli 17bor-2

Strain Deinococcus irradiatisoli 17bor-2 was isolated from a soil sample exposed to γ radiation at Seoul Women's University, Republic of Korea. The genus Deinococcus is a Gram-negative, coccus-shaped, and extremophilic bacterium, well renowned as being a radiation-resistant bacterium. Therefore, the mechanism behind the resistance to radiation and the gene responsible for the resistance could be helpful for detailed experimental studies with biotechnological applications. To study the involvement of genes in UV radiation resistance in strain 17bor-2, the genomic DNA of the strain was sequenced and constructed using the Pacific Biosciences RS II system. In addition, the complete genome sequence of strain 17bor-2 was annotated and interpreted using the Genomes-Expert Review (IMG-ER) system, along with Prodigal and JGI GenePRIMP analysis. The genome analysis of strain 17bor-2 revealed evidence of excinuclease UvrABC genes, which are key enzymes in the nucleotide excision repair (NER) mechanism, as well as genes from the recA-dependent and recQ pathways. The genome of strain Deinococcus irradiatisoli 17bor-2 was a circular chromosome comprising 3,052,043 bp with a GC content of 67.0%, including 2911 coding sequences (CDs), 49 tRNA genes, and 9 rRNA genes. In addition, their complete genome sequence annotation features provided evidence that radiation resistance genes play a central part in adaptation against extreme environmental conditions. In recent decades, excision repair genes have been indicated in considerable detail for both prokaryote and eukaryote resistance against UV-C radiation.

Protective Effects of Cinnamaldehyde on the Oxidative Stress, Inflammatory Response, and Apoptosis in the Hepatocytes of Salmonella Gallinarum-Challenged Young Chicks

The development of novel therapeutics to treat multidrug-resistant pathogenic infections like Salmonella gallinarum is the need of the hour. Salmonella infection causes typhoid fever, jaundice, and Salmonella hepatitis resulting in severe liver injury. Natural compounds have been proved beneficial for the treatment of these bacterial infections. The beneficial roles of cinnamaldehyde due to its antibacterial, anti-inflammatory, and antioxidative properties have been determined by many researchers. However, alleviation of liver damage caused by S. gallinarum infection to young chicks by cinnamaldehyde remains largely unknown. Therefore, this study was performed to identify the effects of cinnamaldehyde on ameliorating liver damage in young chicks. Young chicks were intraperitoneally infected with S. gallinarum and treated with cinnamaldehyde orally. Liver and serum parameters were investigated by qRT-PCR, ELISA kits, biochemistry kits, flow cytometry, JC-1 dye experiment, and transcriptome analysis. We found that ROS, cytochrome c, mitochondrial membrane potential (Ψm), caspase-3 activity, ATP production, hepatic CFU, ALT, and AST, which were initially increased by Salmonella infection, significantly ( $P<0.05$ ) decreased by cinnamaldehyde treatment at 1, 3, and 5 days postinfection (DPI). In addition, S. gallinarum infection significantly increased proinflammatory gene expression (IL-1β, IL-6, IL-12, NF-κB, TNF-α, and MyD-88) and decreased the expression of anti-inflammatory genes (IL-8, IL-10, and iNOS); however, cinnamaldehyde reverted these effects at 1, 3, and 5 DPI. Transcriptome analysis showed that S. gallinarum modulates certain genes of the AMPK-mTOR pathway for its survival and replication, and these pathway modulations were reversed by cinnamaldehyde treatment. We concluded that cinnamaldehyde ameliorates inflammation and apoptosis by suppressing NF-Kβ/caspase-3 pathway and reverts the metabolic changes caused by S. gallinarum infection via modulating the AMPK-mTOR pathway. Furthermore, cinnamaldehyde has antibacterial, anti-inflammatory, antioxidative, and antiapoptotic properties against S. gallinarum-challenged young chicks and can be a candidate novel drug to treat salmonellosis in poultry production.

Phycocyanin-functionalized black phosphorus quantum dots enhance PDT/PTT therapy by inducing ROS and irreparable DNA damage

To achieve synergistic photodynamic-photothermic therapy, we fabricate the novel phycocyanin (PC)-functionalized black phosphorus quantum dots (BPQDs) referred as PC@BPQDs through a one-step stirring method. PC@BPQDs are characterized by the feature of possessing both near-infrared (NIR) induced photothermal and photodynamic activity. The PC layer not only effectively alleviates plasma protein adsorption onto BPQDs, but also functionally boosts the photothermal therapy efficiency by enhanced ROS release, resulting in increased apoptosis in vitro. Moreover, PC@BPQDs eradicate tumors with high efficacy and low toxicity in vivo. Thus, PC@BPQDs have a promising potential in future therapeutic implications.

Pink1/PARK2/mROS-Dependent Mitophagy Initiates the Sensitization of Cancer Cells to Radiation

Autophagy plays a double-edged sword for cancer; particularly, mitophagy plays important roles in the selective degradation of damaged mitochondria. However, whether mitophagy is involved in killing effects of tumor cells by ionizing radiation (IR) and its underlying mechanism remain elusive. The purpose is to evaluate the effects of mitochondrial ROS (mROS) on autophagy after IR; furthermore, we hypothesized that KillerRed (KR) targeting mitochondria could induce mROS generation, subsequent mitochondrial depolarization, accumulation of Pink1, and recruitment of PARK2 to promote the mitophagy. Thereby, we would achieve a new strategy to enhance mROS accumulation and clarify the roles and mechanisms of radiosensitization by KR and IR. Our data demonstrated that IR might cause autophagy of both MCF-7 and HeLa cells, which is related to mitochondria and mROS, and the ROS scavenger N-acetylcysteine (NAC) could reduce the effects. Based on the theory, mitochondrial targeting vector sterile α- and HEAT/armadillo motif-containing protein 1- (Sarm1-) mtKR has been successfully constructed, and we found that ROS levels have significantly increased after light exposure. Furthermore, mitochondrial depolarization of HeLa cells was triggered, such as the decrease of Na⁺K⁺ ATPase, Ca²⁺Mg²⁺ ATPase, and mitochondrial respiratory complex I and III activities, and mitochondrial membrane potential (MMP) has significantly decreased, and voltage-dependent anion channel 1 (VDAC1) protein has significantly increased in the mitochondria. Additionally, HeLa cell proliferation was obviously inhibited, and the cell autophagic rates dramatically increased, which referred to the regulation of the Pink1/PARK2 pathway. These results indicated that mitophagy induced by mROS can initiate the sensitization of cancer cells to IR and might be regulated by the Pink1/PARK2 pathway.

Methylobacterium radiodurans sp. nov., a novel radiation-resistant Methylobacterium

A Gram-negative, aerobic, flagellated, rod-shaped, and pink-pigmented bacterium, strain 17Sr1-43 ^T, was isolated from a soil sample collected in Nowongu, Seoul, Korea. The isolate could grow at 18-37 °C (optimum, 28-30 °C), pH 6.0-8.0 (optimum, pH 7.0) and in the presence of 0-1.0% (w/v) NaCl (optimum, 0%) with aeration. The major cellular fatty acids were summed feature 8 (C_18:1 ω7c and/or C_18:1 ω6c) and summed feature 2 (iso-C_16:1 I and/or C_14:0 3-OH). The predominant respiratory quinone was Q-10 and the major polar lipids were phosphatidylethanolamine, phosphatidylglycerol, phospholipid, and diphosphatidylglycerol. The G + C content of genomic DNA was 69.1 mol%. Strain 17Sr1-43 ^T was closely related to Methylobacterium gregans KACC 14808 ^T (98.4% 16S rRNA gene sequence similarity), Methylobacterium hispanicum KACC 11432 ^T (97.9%), and Methylobacterium phyllosphaerae CBMB27^T (96.1%). The complete genome of strain 17Sr1-43 ^T contains essential genes related to DNA repair processes including bacterial RecBCD dependent pathway and UmuCD system. Based on the phenotypic, genotypic, and chemotaxonomic characteristics, strain 17Sr1-43 ^T represents a novel species in the genus Methylobacterium, for which the name Methylobacterium radiodurans sp. nov. is proposed. The type strain is strain 17Sr1-43 ^T (= KCTC 52906 ^T = NBRC 112875 ^T).

Hymenobacter setariae sp. nov., isolated from the ubiquitous weedy grass Setaria viridis

A Gram-stain-negative, short-rod, aerobic, non-motile, red to pink-pigmented bacterium, designated Fur1T, was isolated from the dry spikelet clusters of a plant called Setaria viridis near Dongguk University. Phylogenetic analysis conducted based on 16S rRNA gene sequences indicated that strain Fur1T belonged to the genus Hymenobacter of the family Hymenobacteraceae . The 16S rRNA gene of Fur1T showed highest sequence similarity to those of Hymenobacter metalli KACC 17381T (97.5 %) and Hymenobacter marinus KACC 19042T (97.1 %). Growth occurred at 4–37 °C (optimum, 25–28 °C), up to 1.0 % NaCl (optimum, 0 %) and pH 5.5–9.0 (optimum, pH 6.0–7.5). The major fatty acids of strain Fur1T were identified as iso-C15 : 0, C16 : 1  ω5c, anteiso-C15 : 0, summed feature 3 (comprising C16 : 1  ω7c and/or C16 : 1  ω6c) and summed feature 4 (comprising anteiso-C17 : 1B and/or iso-C17 : 1I) as the major cellular fatty acids. The predominant respiratory quinone was identified as MK-7. The polar lipids were phosphatidylethanolamine, five unidentified aminophospholipids, two unidentified phospholipids, one unidentified glycolipid and one unidentified polar lipid. The genomic DNA G+C content based on the draft genome sequence was 58.7 mol%. DNA–DNA relatedness between strain Fur1T and its closest relative was below 70 %. Characterization based on phylogenetic, chemotaxonomic and phenotypic analyses clearly indicated that strain Fur1T represents a novel species of the genus Hymenobacter , for which the name Hymenobacter setariae sp. nov. is proposed. The type strain is Fur1T (=KACC 19903T=NBRC=113691T).

Light-Activated Heterostructured Nanomaterials for Antibacterial Applications

An outbreak of a bacterial contagion is a critical threat for human health worldwide. Recently, light-activated heterostructured nanomaterials (LAHNs) have shown potential as antibacterial agents, owing to their unique structural and optical properties. Many investigations have revealed that heterostructured nanomaterials are potential antibacterial agents under light irradiation. In this review, we summarize recent developments of light-activated antibacterial agents using heterostructured nanomaterials and specifically categorized those agents based on their various light harvesters. The detailed antibacterial mechanisms are also addressed. With the achievements of LAHNs as antibacterial agents, we further discuss the challenges and opportunities for their future clinical applications.

Red-blue light irradiation in the prevention of surgical wound infection after mandibular distraction using internal distractors in hemifacial microsomia: A randomized trial

BACKGROUND

Postoperative infection is a complication of mandibular distraction osteogenesis (DO) in patients with hemifacial microsomia (HFM). The risk of surgical wound infection in DO is reported to be high due to the long duration of the distraction process. Treatment during the perioperative period is critical in combating infection.

AIM

This study aimed to evaluate the effectiveness of red-blue irradiation in the prevention of surgical wound infection after mandibular distraction.

METHODS

In our single-centered, randomized clinical study, 118 patients diagnosed with HFM who had undergone DO between April 2016 and April 2018 were included. The patients were randomly divided into two groups: the experimental group received red-blue irradiation treatment and the control group received white-light irradiation.

RESULTS

None of the infections occurring in this study resulted in serious complications. The postoperative infection rate during the 4 weeks after DO in the experimental group was 1.7%, whereas that in the control group was 13.6% (p = 0.016) (based on a modified NHSN wound infection criterion). The total social cost during the active period for the experimental group was 3386840 RMB, 5.12% higher than for the control group (3221882 RMB).

CONCLUSIONS

Red-blue irradiation is recommended as adjunctive therapy after mandibular distraction osteogeneis in HFM.

ROS Induced by KillerRed Targeting Mitochondria (mtKR) Enhances Apoptosis Caused by Radiation via Cyt c/Caspase-3 Pathway

During radiotherapy, reactive oxygen species- (ROS-) induced apoptosis is one of the main mechanism of radiation. Based on KillerRed which can induce ROS burst in different cell substructures, here we hypothesized that KillerRed targeting mitochondria (mtKR) could induce ROS to enhance apoptosis by radiation. In this study, empty vector, mtKR, and mtmCherry plasmids were successfully constructed, and mitochondrial localization were detected in COS-7 and HeLa cells. After HeLa cells were transfected and irradiated by visible light and X-rays, ROS levels, mitochondrial membrane potential (Δψ_m), ATPase activities, adenosine triphosphate (ATP) content, apoptosis, and the expressions of mRNA and protein were measured, respectively. Data demonstrated that the ROS levels significantly increased after light exposure, and adding extra radiation, voltage-dependent anion channel 1 (VDAC1) protein increased in the mitochondria, while Na⁺-K⁺ and Ca²⁺-Mg²⁺ ATPase activities, ATP content, and Δψ_m significantly reduced. Additionally, the cell apoptotic rates dramatically increased, which referred to the increase of cytochrome c (Cyt c), caspase-9, and caspase-3 mRNA expressions, and Cyt c protein was released from the mitochondria into the cytoplasm; caspase-9 and -3 were activated. These results indicated that mtKR can increase the production of ROS, enhance mitochondrial dysfunction, and strengthen apoptosis by radiation via Cyt c/caspase-3 pathway.

The Salmonella effector SopB prevents ROS-induced apoptosis of epithelial cells by retarding TRAF6 recruitment to mitochondria

Microbial pathogens enter host cells by injecting effector proteins of the Type III secretion system (T3SS), which facilitate pathogen translocation across the host cell membrane. These effector proteins exert their effects by modulating a variety of host innate immune responses, thereby facilitating bacterial replication and systemic infection. Salmonella enterica serovar typhimurium (S.typhimurium) is a clinically important pathogen that causes food poisoning and gastroenteritis. The SopB effector protein of S. typhimurium, encoded by Salmonella pathogenicity islands (SPI)-1 T3SS, protects host epithelial cells from infection-induced apoptosis. However, how SopB influences apoptosis induction remains unclear. Here, we investigated the mechanism of SopB action in host cells. We found that SopB inhibits infection-induced apoptosis by attenuating the production of reactive oxygen species (ROS) in mitochondria, the crucial organelles for apoptosis initiation. Further investigation revealed that SopB binds to cytosolic tumor necrosis factor receptor associated factor 6 (TRAF6) and forms a trap preventing the mitochondrial recruitment of TRAF6, an essential event for ROS generation within mitochondria. By studying the response of Traf6(+/+) and Traf6(-/-)mouse embryonic fibroblasts to S. typhimurium infection, we found that TRAF6 promoted apoptosis by increasing ROS accumulation, which led to increased Bax/Bcl-2 ratio, Bax recruitment to mitochondrial membrane, and release of Cyt c into the cytoplasm. These findings show that SopB suppresses host cell apoptosis by binding to TRAF6 and preventing mitochondrial ROS generation.

Targeted Photodynamic Virotherapy Armed with a Genetically Encoded Photosensitizer

Photodynamic therapy (PDT) is a minimally invasive antitumor therapy that eradicates tumor cells through a photosensitizer-mediated cytotoxic effect upon light irradiation. However, systemic administration of photosensitizer often makes it difficult to avoid a photosensitive adverse effect. The red fluorescent protein KillerRed generates reactive oxygen species (ROS) upon green light irradiation. Here, we show the therapeutic potential of a novel tumor-specific replicating photodynamic viral agent (TelomeKiller) constructed using the human telomerase reverse transcriptase (hTERT) promoter. We investigated the light-induced antitumor effect of TelomeKiller in several types of human cancer cell lines. Relative cell viability was investigated using an XTT assay. The in vivo antitumor effect was assessed using subcutaneous xenografted tumor and lymph node metastasis models. KillerRed accumulation resulted in ROS generation and apoptosis in light-irradiated cancer cells. Intratumoral injection of TelomeKiller efficiently delivered the KillerRed protein throughout the tumors and exhibited a long-lasting antitumor effect with repeated administration and light irradiation in mice. Moreover, intratumorally injected TelomeKiller could spread into the regional lymph node area and eliminate micrometastasis with limited-field laser irradiation. Our results suggest that KillerRed has great potential as a novel photosensitizer if delivered with a tumor-specific virus-mediated delivery system. TelomeKiller-based PDT is a promising antitumor strategy to efficiently eradicate tumor cells.

Selenium doped Ni–Ti layered double hydroxide (Ni–Ti LDH) films with selective inhibition effect to cancer cells and bacteria

Selenium doped LDH films effectively inhibit the growth of cancer cells and bacteria with little adverse effect on normal cells. The selectivity stems from the synergistic effect of the doped selenium and hydroxyl radicals produced by the LDH films.

A genetically-encoded KillerRed protein as an intrinsically generated photosensitizer for photodynamic therapy

Photodynamic therapy (PDT) has received considerable attention as a therapeutic treatment for cancer and other diseases; however, it is frequently accompanied by prolonged phototoxic reaction of the skin due to slow clearance of synthetic photosensitizers (PSs) administered externally. This study was designed to investigate the genetic use of pKillerRed-mem, delivered using complexes of chitosan (CS) and poly(γ-glutamic acid) (γPGA), to intracellularly express a membrane-targeted KillerRed protein that can be used as a potential PS for PDT. Following transfection with CS/pKillerRed/γPGA complexes, a red fluorescence protein of KillerRed was clearly seen at the cellular membranes. When exposed to green-light irradiation, the KillerRed-positive cells produced an excessive amount of reactive oxygen species (ROS) in a time-dependent manner. Data from viability assays indicate that ROS have an important role in mediating KillerRed-induced cytotoxicity, apoptosis, and anti-proliferation, suggesting that KillerRed can be used as an intrinsically generated PS for PDT treatments. Notably, the phototoxic reaction of KillerRed toward cells gradually became negligible over time, presumably because of its intracellular degradability. These experimental results demonstrate that this genetically encoded KillerRed is biodegradable and has potential for PDT-induced destruction of diseased cells.

Spatial localization of genes determined by intranuclear DNA fragmentation with the fusion proteins lamin KRED and histone KRED und visible light

The highly organized DNA architecture inside of the nuclei of cells is accepted in the scientific world. In the human genome about 3 billion nucleotides are organized as chromatin in the cell nucleus. In general, they are involved in gene regulation and transcription by histone modification. Small chromosomes are localized in a central nuclear position whereas the large chromosomes are peripherally positioned. In our experiments we inserted fusion proteins consisting of a component of the nuclear lamina (lamin B1) and also histone H2A, both combined with the light inducible fluorescence protein KillerRed (KRED). After activation, KRED generates reactive oxygen species (ROS) producing toxic effects and may cause cell death. We analyzed the spatial damage distribution in the chromatin after illumination of the cells with visible light. The extent of DNA damage was strongly dependent on its localization inside of nuclei. The ROS activity allowed to gain information about the location of genes and their functions via sequencing and data base analysis of the double strand breaks of the isolated DNA. A connection between the damaged gene sequences and some diseases was found.

Instantaneous inactivation of cofilin reveals its function of F-actin disassembly in lamellipodia

Cofilin is a key regulator of the actin cytoskeleton. It can sever actin filaments, accelerate filament disassembly, act as a nucleation factor, recruit or antagonize other actin regulators, and control the pool of polymerization-competent actin monomers. In cells these actions have complex functional outputs. The timing and localization of cofilin activity are carefully regulated, and thus global, long-term perturbations may not be sufficient to probe its precise function. To better understand cofilin's spatiotemporal action in cells, we implemented chromophore-assisted laser inactivation (CALI) to instantly and specifically inactivate it. In addition to globally inhibiting actin turnover, CALI of cofilin generated several profound effects on the lamellipodia, including an increase of F-actin, a rearward expansion of the actin network, and a reduction in retrograde flow speed. These results support the hypothesis that the principal role of cofilin in lamellipodia at steady state is to break down F-actin, control filament turnover, and regulate the rate of retrograde flow.

A genetically-encoded photosensitiser demonstrates killing of bacteria by purely endogenous singlet oxygen

TagRFP, a fluorescent protein capable of photosensitizing the production of singlet oxygen, was expressed in E. coli. Subsequent exposure to green light induced bacterial cell death in a light-dose dependent manner. It is demonstrated for the first time that intracellular singlet oxygen is sufficient to kill bacteria.