Ferulic acid-arabinoxylan conjugates: Synthesis, characterization and applications in antibacterial film formation.

A novel antibacterial film based on arabinoxylan (AX) was prepared by introducing ferulic acid (FA) to AX through a laccase-catalyzed procedure. The ferulic acid-arabinoxylan conjugates (FA-AX conjugates) have been characterized. Results showed that FA was successfully grafted onto the AX chains by covalent linkages, likely through nucleophilic addition between O-Ph in the phenolic hydroxyl group of FA, or through Michael addition via O-quinone intermediates. FA-AX conjugates showed improved crystallinity, thermal stability, and rheological properties, as well as a distinct surface morphology, compared with those of native AX. Moreover, FA-AX conjugates exhibited enhanced antibacterial ability against Staphylococcus aureus, Escherichia coli, Shewanella sp., and Pseudomonas sp. Mechanistic studies revealed that the enhanced antibacterial ability was due to the penetration of bacterial membrane by the phenolic molecule and the steric effect of FA-AX conjugates. The study demonstrates that the laccase-induced grafting method was effective in producing FA-AX conjugates; we have demonstrated its antibacterial ability and great potential in prolonging the shelf life of fresh seafood products.

Multifunctional electromagnetic wave absorbing carbon fiber/Ti3C2TX MXene fabric with superior near-infrared laser dependent photothermal antibacterial behaviors.

Developing multifunctional materials which could simultaneously possess anti-bacterial ability and electromagnetic (EM) absorption ability during medical care is quite essential since the EM waves radiation and antibiotic-resistant bacteria are threatening people's health. In this work, the multifunctional carbon fiber/Ti3C2Tx MXene (CM) were synthesized through repeated dip-coating and following in-situ growth method. The as-fabricated CF/MXene displayed outstanding EM wave absorption and highly efficient photothermal converting ability. The minimum reflection loss (RL) of -57.07 dB and ultra-broad absorption of 7.74 GHz could be achieved for CM composites. By growth of CoNi-layered double hydroxides (LDHs) sheets onto MXene, the absorption bandwidth for carbon fiber/Ti3C2Tx MXene layered double hydroxides (CML) could be reach 5.44 GHz, which could cover the whole Ku band. The excellent photothermal effect endow the CM composites with excellent antibacterial performance. The antibacterials tests indicated that nearly 100 % bactericidal efficiency against E. acoil and S. aureus was obtained for the CM composite after exposure to near-infrared region (NIR) irradiation. This work provides a promising candidate to combat medical device-related infections and EM pollution.

Phytic Acid-Gallium Network on a Polyimide Fiber Woven Fabric as an Artificial Ligament for Boosting Ligament-Bone Healing and Infection Treatment.

The development of an artificial ligament with a multifunction of promoting bone formation, inhibiting bone resorption, and preventing infection to obtain ligament-bone healing for anterior cruciate ligament (ACL) reconstruction still faces enormous challenges. Herein, a novel artificial ligament based on a PI fiber woven fabric (PIF) was fabricated, which was coated with a phytic acid-gallium (PA-Ga) network via a layer-by-layer assembly method (PFPG). Compared with PIF, PFPG with PA-Ga coating significantly suppressed osteoclastic differentiation, while it boosted osteoblastic differentiation in vitro. Moreover, PFPG obviously inhibited fibrous encapsulation and bone absorption while accelerating new bone regeneration for ligament-bone healing in vivo. PFPG remarkably killed bacteria and destroyed biofilm, exhibiting excellent antibacterial properties in vitro as well as anti-infection ability in vivo, which were ascribed to the release of Ga ions from the PA-Ga coating. The cooperative effect of the surface characteristics (e.g., hydrophilicity/surface energy and protein absorption) and sustained release of Ga ions for PFPG significantly enhanced osteogenesis while inhibiting osteoclastogenesis, thereby achieving ligament-bone integration as well as resistance to infection. In summary, PFPG remarkably facilitated osteoblastic differentiation, while it suppressed osteoclastic differentiation, thereby inhibiting osteoclastogenesis for bone absorption while accelerating osteogenesis for ligament-bone healing. As a novel artificial ligament, PFPG represented an appealing option for graft selection in ACL reconstruction and displayed considerable promise for application in clinics.

Characterization of Myxovirus resistance (Mx) gene from Chinese seabass Lateolabrax maculatus: Insights into the evolution and function of Mx genes.

Chinese seabass (Lateolabrax maculatus) stands out as one of the most sought-after and economically significant species in aquaculture within China. Diseases of L. maculatus occur frequently due to the degradation of the germplasm, the aggravation of environmental pollution of water, and the reproduction of pathogenic microorganisms, inflicting considerable economic losses on the Chinese seabass industry. The Myxovirus resistance (Mx) gene plays pivotal roles in the antiviral immune response ranging from mammals to fish. However, the function of the Mx gene in L. maculatus is still unknown. Firstly, the origin and evolutionary history of Mx proteins was elucidated in this study. Subsequently, an Mx gene from L. maculatus (designed as LmMxA gene) was identified, and its functions in combating antiviral and antibacterial threats were investigated. Remarkably, our findings suggested that while Mx group genes were present in chordates, DYN group genes were present in everything from single-celled animals to humans. Furthermore, our investigation revealed that the LmMxA mRNA level increased in the kidney, spleen and liver subsequent to Vibrio anguillarum and poly(I:C) challenged. Immunofluorescence analysis indicated that LmMxA is predominantly localization in the nucleus and the cytoplasm. Notably, the expression of MAVS, IFN1 and Mx1 increased when LmMxA was overexpression within the EPC cells. Moreover, through assessment via cytopathic effect (CPE), virus titer, and antibacterial activity, it becomes evident that LmMxA exerts a dual role in bolstering both antiviral and antibacterial immune responses. These compelling findings laid the foundation for further exploring the mechanism of LmMxA in response to innate immunity of L. maculatus.

The research status and future direction of polyetheretherketone in dental implant -A comprehensive review.

Currently, dental implants primarily rely on the use of titanium and titanium alloys. However, the extensive utilization of these materials in clinical practice has unveiled various problems including stress shielding, corrosion, allergic reactions, cytotoxicity, and image artifacts. As a result, polyetheretherketone (PEEK) has emerged as a notable alternative due to its favorable mechanical properties, corrosion resistance, wear resistance, biocompatibility, radiation penetrability and MRI compatibility. Meanwhile, the advancement and extensive application of 3D printing technology has expanded the range of medical applications for PEEK, including artificial spines, skulls, ribs, shinbones, hip joints, and temporomandibular joints. In this review, we aim to assess the advantages and disadvantages of PEEK as a dental implant material, summarize the measures taken to address its shortcomings and their effects, and provide insight into the future potential of PEEK in dental implant applications, with the goal of offering guidance and reference for future research endeavors.

Antibacterial tellurium-containing polycarbonate drug carriers to eliminate intratumor bacteria for synergetic chemotherapy against colorectal cancer.

Intratumor microbes have attracted great attention in cancer research due to its influence on the tumorigenesis, progression and metastasis of cancer. However, the therapeutic strategies targeting intratumoral microbes are still in their infancy. Specific microorganisms, such as Fusobacterium nucleatum (F. nucleatum), are abundant in various cancer and always result in the CRC progression and chemotherapy resistance. Here, a combined anticancer and antibacterial therapeutic strategy is proposed to deliver antitumor drug to the tumors containing intratumor microbiota by the antibacerial polymeric drug carriers. We construct oral tellurium-containing drug carriers using a complex of tellurium-containing polycarbonate with cisplatin (PTE@CDDP). The results show that the particle size of the prepared nanoparticles could be maintained at about 105 nm in the digestive system environment, which is in line with the optimal particle size of oral nanomedicine. In vitro mechanism study indicates that the tellurium-containing polymers are highly effective in killing F.nucleatum through a membrane disruption mechanism. The pharmacokinetic experiments confirmed that PTE@CDDP has the potential function of enhancing the oral bioavailability of cisplatin. Both in vitro and in vivo studies show that PTE@CDDP could inhibit intratumor F.nucleatum and lead to a reduction in cell proliferation and inflammation in the tumor site. Together, the study identifies that the CDDP-loaded tellurium-containing nanoparticles have great potential for treating the F.nucleatum-promoted colorectal cancer (CRC) by combining intratumor microbiota modulation and chemotherapy. The synergistic therapeutic strategy provide new insight into treating various cancers combined with bacterial infection. STATEMENT OF SIGNIFICANCE: The synthesized antibacterial polymer was first employed to remodel the intratumor microbes in tumor microenvironment (TME). Moreover, it was the first report of tellurium-containing polymers against F.nucleatum and employed for treatment of the CRC. A convenient oral dosage form of cisplatin (CDDP)-loaded tellurium-containing nanoparticles (PTE@CDDP) was adopted here, and the synergistic antibacterial/chemotherapy effect occurred. The PTE@CDDP could quickly and completely eliminate F.nucleatum in a safe dose. In the CRC model, PTE@CDDP effectively reversed the inflammation level and even restored the intestinal barrier damaged by F.nucleatum. The ultrasensitive ROS-responsiveness of PTE@CDDP triggered the fast oxidation and efficient drug release of CDDP and thus a highly efficient apoptosis of the tumors. Therefore, the tellurium-containing polymers are expected to serve as novel antibacterial agents in vivo and have great potential in the F.nucleatum-associated cancers. The achievements provided new insight into treating CRC and other cancers combined with bacterial infection.

Hydrogel-Based Treatment of House Dust Mite-Induced Atopic Dermatitis through Triple Cleaning of Mites, Bacteria, and ROS-Related Inflammation.

Atopic dermatitis (AD) is a chronic and recurrent inflammatory disease caused by abnormalities in skin immunoregulation. House dust mite can directly damage the skin barrier and thus sensitize the skin, which is one of the main allergens inducing AD in humans and widely exists in daily life. Meanwhile, the accompanying bacterial infections and exposure to additional allergens exacerbate the condition by generating excessive reactive oxygen species (ROS). Herein, we have developed the CPDP hydrogel with injectable and self-healing ability to combat pathogenic microorganisms and inflammatory environments for AD therapy. In vitro experiments have affirmed the efficacy of the CPDP hydrogel in combating mites, killing bacteria, and scavenging ROS. In a mouse model closely mimicking HDM-induced AD, the CPDP hydrogel has shown superior therapeutic effects, including reducing epidermal thickness and mast cell count, increasing collagen deposition, as well as down-regulating pro-inflammatory factors.

Doping-Engineered Piezoelectric Ultrathin Nanosheets for Synergistically Piezo-Chemocatalytic Antitumor and Antibacterial Therapies Against Cutaneous Melanoma.

The post-surgical melanoma recurrence and wound infections have persistently troubled clinical management. Piezocatalytic therapy features high efficiency in generating reactive oxygen species (ROS) for tumor therapy, but it faces limitations in piezoelectricity and redox-active site availability. Herein, Fe-doped ultrathin Bi4Ti3O12 nanosheets (designated as Fe-UBTO NSs) with synergistically piezo-chemocatalytic activity are engineered for antitumor and antibacterial treatment against cutaneous melanoma. The doping-engineered strategy induces oxygen vacancies and lattice distortions in Fe-UBTO NSs, which narrows bandgap to enhance piezocatalytic 1O2 and H2O2 generation by improving the electron-hole pairs separation, hindering their recombination, and increasing oxygen adsorption. Moreover, Fe doping establishes a piezo-chemocatalytic system, in which the piezocatalysis enables the self-supply of H2O2 and expedites electron transfer in Fenton reactions, inducing increased ·OH production. Besides, the atomic-level thickness and expanded surface area enhance the sensitivity to ultrasound stimuli and expose more redox-active sites, augmenting the piezo-chemocatalytic efficiency, and ultimately leading to abundant ROS generation. The Fe-UBTO-mediated piezo-chemocatalytic therapy causes intracellular oxidative stress, triggering apoptosis and excessive autophagy of tumor cells. Moreover, this strategy accelerates wound healing by facilitating sterilization, angiogenesis, and collagen deposition. This work provides distinct options to develop doping-engineered ultrathin nanosheets with augmented piezo-chemocatalytic activity for postoperative management of cutaneous melanoma.

Potential therapeutic agents of Bombyx mori silk cocoon extracts from agricultural product for inhibition of skin pathogenic bacteria and free radicals.

Background: Pathogenic bacteria are the cause of most skin diseases, but issues such as resistance and environmental degradation drive the need to research alternative treatments. It is reported that silk cocoon extract possesses antioxidant properties. During silk processing, the degumming of silk cocoons creates a byproduct that contains natural active substances. These substances were found to have inhibitory effects on bacterial growth, DNA synthesis, the pathogenesis of hemolysis, and biofilm formation. Thus, silk cocoon extracts can be used in therapeutic applications for the prevention and treatment of skin pathogenic bacterial infections. Methods: The extract of silk cocoons with pupae (SCP) and silk cocoons without pupae (SCWP) were obtained by boiling with distilled water for 9 h and 12 h, and were compared to silkworm pupae (SP) extract that was boiled for 1 h. The active compounds in the extracts, including gallic acid and quercetin, were determined using high-performance liquid chromatography (HPLC). Furthermore, the total phenolic and flavonoid content in the extracts were investigated using the Folin-Ciocalteu method and the aluminum chloride colorimetric method, respectively. To assess antioxidant activity, the extracts were evaluated using the 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging assay. Additionally, the minimal inhibitory concentration (MIC) and minimal bactericidal concentration (MBC) of silk extracts and phytochemical compounds were determined against skin pathogenic bacteria. This study assessed the effects of the extracts and phytochemical compounds on growth inhibition, biofilm formation, hemolysis protection, and DNA synthesis of bacteria. Results: The HPLC characterization of the silk extracts showed gallic acid levels to be the highest, especially in SCP (8.638-31.605 mg/g extract) and SP (64.530 mg/g extract); whereas quercetin compound was only detected in SCWP (0.021-0.031 mg/g extract). The total phenolics and flavonoids in silk extracts exhibited antioxidant and antimicrobial activity. Additionally, SCP at 9 h and 12 h revealed the highest anti-bacterial activity, with the lowest MIC and MBC of 50-100 mg/mL against skin pathogenic bacteria including Staphylococcus aureus, methicillin-resistant S. aureus (MRSA), Cutibacterium acnes and Pseudomonas aeruginosa. Hence, SCP extract and non-sericin compounds containing gallic acid and quercetin exhibited the strongest inhibition of both growth and DNA synthesis on skin pathogenic bacteria. The suppression of bacterial pathogenesis, including preformed and matured biofilms, and hemolysis activity, were also revealed in SCP extract and non-sericin compounds. The results show that the byproduct of silk processing can serve as an alternative source of natural phenolic and flavonoid antioxidants that can be used in therapeutic applications for the prevention and treatment of pathogenic bacterial skin infections.

Defect Engineered Bi2Te3 Nanosheets with Enhanced Haloperoxidase Activity for Marine Antibiofouling.

Defective bismuth telluride (Bi2Te3) nanosheets, an artificial nanozyme mimicking haloperoxidase activity (hPOD), show promise as eco-friendly, bactericidal, and antimicrofouling materials by enhancing cytotoxic hypohalous acid production from halides and H2O2. Microscopic and spectroscopic characterization reveals that controlled NaOH (upto X = 250 µL) etching of the nearly inactive non-transition metal chalcogenide Bi2Te3 nanosheets creates controlled defects (d), such as Bi3+species, in d-Bi2Te3-X that induces enhanced hPOD activity. d-Bi2Te3-250 exhibits approximately eight-fold improved hPOD than the as-grown Bi2Te3 nanosheets. The antibacterial activity of d-Bi2Te3-250 nanozymes, studied by bacterial viability, show 1, and 45% viability for Staphylococcus aureus and Pseudomonas aeruginosa, respectively, prevalent in marine environments. The hPOD mechanism is confirmed using scavengers, implicating HOBr and singlet oxygen for the effect. The antimicrofouling property of the d-Bi2Te3-250 nanozyme has been studied on Pseudomonas aeruginosa biofilm in a lab setting by multiple assays, and also on titanium (Ti) plates coated with the nanozyme mixed commercial paint, exposed to seawater in a real setting. All studies, including direct microscopic evidence, exhibit inhibition of microfouling, up to ≈73%, in the presence of nanozymes. This approach showcases that defect engineering can induce antibacterial, and antimicrofouling activity in non-transition metal chalcogenides, offering an inexpensive alternative to noble metals.

Volatile Organic Compounds Produced by a Deep-Sea Bacterium Efficiently Inhibit the Growth of Pseudomonas aeruginosa PAO1.

The deep-sea bacterium Spongiibacter nanhainus CSC3.9 has significant inhibitory effects on agricultural pathogenic fungi and human pathogenic bacteria, especially Pseudomonas aeruginosa, the notorious multidrug-resistant pathogen affecting human public health. We demonstrate that the corresponding antibacterial agents against P. aeruginosa PAO1 are volatile organic compounds (VOCs, namely VOC-3.9). Our findings show that VOC-3.9 leads to the abnormal cell division of P. aeruginosa PAO1 by disordering the expression of several essential division proteins associated with septal peptidoglycan synthesis. VOC-3.9 hinders the biofilm formation process and promotes the biofilm dispersion process of P. aeruginosa PAO1 by affecting its quorum sensing systems. VOC-3.9 also weakens the iron uptake capability of P. aeruginosa PAO1, leading to reduced enzymatic activity associated with key metabolic processes, such as reactive oxygen species (ROS) scavenging. Overall, our study paves the way to developing antimicrobial compounds against drug-resistant bacteria by using volatile organic compounds.

Sulfated Chitosan-Modified CuS Nanocluster: A Versatile Nanoformulation for Simultaneous Antibacterial and Bone Regenerative Therapy in Periodontitis.

Periodontitis, a prevalent chronic inflammatory disease worldwide, is triggered by periodontopathogenic bacteria, resulting in the progressive destruction of periodontal tissue, particularly the alveolar bone. To effectively address periodontitis, this study proposed a nanoformulation known as CuS@MSN-SCS. This formulation involves coating citrate-grafted copper sulfide (CuS) nanoparticles with mesoporous silica (MSNs), followed by surface modification using amino groups and sulfated chitosan (SCS) through electrostatic interactions. The objective of this formulation is to achieve efficient bacteria removal by inducing ROS signaling pathways mediated by Cu2+ ions. Additionally, it aims to promote alveolar bone regeneration through Cu2+-induced pro-angiogenesis and SCS-mediated bone regeneration. As anticipated, by regulating the surface charges, the negatively charged CuS nanoparticles capped with sodium citrate were successfully coated with MSNs, and the subsequent introduction of amine groups using (3-aminopropyl)triethoxysilane was followed by the incorporation of SCS through electrostatic interactions, resulting in the formation of CuS@MSN-SCS. The developed nanoformulation was verified to not only significantly exacerbate the oxidative stress of Fusobacterium nucleatum, thereby suppressing bacteria growth and biofilm formation in vitro, but also effectively alleviate the inflammatory response and promote alveolar bone regeneration without evident biotoxicity in an in vivo rat periodontitis model. These findings contribute to the therapeutic effect on periodontitis. Overall, this study successfully developed a nanoformulation for combating bacteria and facilitating alveolar bone regeneration, demonstrating the promising potential for clinical treatment of periodontitis.

Antibacterial, antioxidant activities of lactic acid bacteria-bioconversioned almond extract.

This study was about bioconversion of almonds by lactic acid bacteria. There are two bacteria used for bioconversion of almond extract: Lactiplantibacillus plantarum ATCC14917 and Lacticaseibacillus rhamnosus GG KCTC5033. Almond extract (AE) was inoculated with L. plantarum or L. rhamnosus GG for 3 days. AE inoculated with L. plantarum (LP-AE) and AE inoculated with L. rhamnosus GG (LR-AE) inhibited the growth of Salmonella Typhimurium and the growth of Yersinia enterocolitica by 30 and 75%, respectively compared to AE. LR-AE inhibited 30% of biofilm formation of S. Typhimurium and Y. enterocolitica compared to AE. Antioxidative activity of LP-AE and LR-AE was determined using the 2,2'-zino-bis(3-ethylbenzothiazoline-6-sulfonate) (ABTS) assay. ABTS radical scavenging activity of AE, LP-AE and LR-AE was 53.50%, 80.39% and 83.57%, respectively. The highest level of total polyphenol (89.72 mg Gallic Acid Equivalent (GAE)/g) and flavonoid (194.56 mg Quercetin Equivalent (QCE)/g) contents was found in LR-AE.

Dietary tryptophan improves growth and intestinal health by promoting the secretion of intestinal ß-defensins against enterotoxigenic Escherichia coli F4 in weaned piglets.

Adequate dietary L-tryptophan (Trp) governs intestinal homeostasis in piglets. However, the defensive role of Trp in the diet against enterotoxigenic Escherichia coli F4 (K88) in pigs is still poorly understood. Here, sixty (6.15 ± 1.52 kg, 24-day-old, Duroc × Landrace × Yorkshire) weaned piglets were used for an E. coli F4 attack test in a 2 × 2 factorial design. The growth (ADG, ADFI, GH), immune factors (IL-10, IgA, IgG, IgM), Trp metabolite 5-HT, intestinal morphology (jejunal and colonic VH), mRNA expression of ß-defensins (jejunal BD-127, BD-119, ileal BD-1, BD-127), and abundance of beneficial microorganisms in the colon (Prevotella 9, Lactobacillus, Phascolarctobacterium, Faecalibacterium) were higher in the piglets in the HT (High Trp) and HTK (High Trp, K88) groups than in the LT (Low Trp) and LTK (Low Trp, K88) groups (P<.05), while FCR, diarrhea rate, diarrhea index, serum Trp, Kyn, IDO, D-LA, ET, and abundance of harmful microorganisms in the colon (Spirochaetes, Fusobacteria, Prevotella, Christensenellaceae R7) were lower in the HT and HTK groups than in the LT and LTK groups (P<.05). High Trp reduced the expression of virulence genes (K88 and LT) after E. coli F4 attack (P<.05). The IL-6, TNF-α was lower in the HTK group than in the LT, LTK group (P<.05). In short, a diet containing 0.35% Trp protected piglets from enterotoxigenic E. coli F4 (K88) via Trp metabolism promoting BD expression in the intestinal mucosa, which improved growth and intestinal health.

Poly (vinyl alcohol)/sodium alginate/carboxymethyl chitosan multifunctional hydrogel loading HKUST-1 nanoenzymes for diabetic wound healing.

Bacterial infection, hyperinflammation and hypoxia, which can lead to amputation in severe cases, are frequently observed in diabetic wounds, and this has been a critical issue facing the repair of chronic skin injuries. In this study, a copper-based MOF (TAX@HKUST-1) highly loaded with taxifolin (TAX) with a drug loading of 41.94 ± 2.60 % was prepared. In addition, it has excellent catalase activity, and by constructing an oxygen-releasing hydrogel (PTH) system with calcium peroxide (CaO2), it can be used as a nano-enzyme to promote the generation of oxygen from hydrogen peroxide (H2O2) to provide sufficient oxygen to the wound, and at the same time, solve the problem of the oxidative stress damage caused by excess H2O2 to the cells during the oxygen-releasing process. On the other hand, TAX and HKUST-1 in PTH synergistically promoted antimicrobial and anti-oxidative stress properties, and the bacterial inhibition rate against Staphylococcus aureus and Escherichia coli reached 90 %. In vivo experiments have shown that PTH hydrogel is able to treat diabetic skin repair by inhibiting the expression of inflammation-related proteins and promoting epidermal neogenesis, angiogenesis and collagen deposition.

Antibacterial insights into alternariol and its derivative alternariol monomethyl ether produced by a marine fungus.

Alternaria alternata FB1 is a marine fungus identified as a candidate for plastic degradation in our previous study. This fungus has been recently shown to produce secondary metabolites with significant antimicrobial activity against various pathogens, including methicillin-resistant Staphylococcus aureus (MRSA) and the notorious aquaculture pathogen Vibrio anguillarum. The antibacterial compounds were purified and identified as alternariol (AOH) and its derivative, alternariol monomethyl ether (AME). We found that AOH and AME primarily inhibited pathogenic bacteria (MRSA or V. anguillarum) by disordering cell division and some other key physiological and biochemical processes. We further demonstrated that AOH could effectively inhibit the unwinding activity of MRSA topoisomerases, which are closely related to cell division and are the potential action target of AOH. The antibacterial activities of AOH and AME were verified by using zebrafish as the in vivo model. Notably, AOH and AME did not significantly affect the viability of normal human liver cells at concentrations that effectively inhibited MRSA or V. anguillarum. Finally, we developed the genetic operation system of A. alternata FB1 and blocked the biosynthesis of AME by knocking out omtI (encoding an O-methyl transferase), which facilitated A. alternata FB1 to only produce AOH. The development of this system in the marine fungus will accelerate the discovery of novel natural products and further bioactivity study.IMPORTANCEMore and more scientific reports indicate that alternariol (AOH) and its derivative alternariol monomethyl ether (AME) exhibit antibacterial activities. However, limited exploration of their detailed antibacterial mechanisms has been performed. In the present study, the antibacterial mechanisms of AOH and AME produced by the marine fungus Alternaria alternata FB1 were disclosed in vitro and in vivo. Given their low toxicity on the normal human liver cell line under the concentrations exhibiting significant antibacterial activity against different pathogens, AOH and AME are proposed to be good candidates for developing promising antibiotics against methicillin-resistant Staphylococcus aureus and Vibrio anguillarum. We also succeeded in blocking the biosynthesis of AME, which facilitated us to easily obtain pure AOH. Moreover, based on our previous results, A. alternata FB1 was shown to enable polyethylene degradation.

Visible-Light-Driven Inactivation of Bacteria and H2 Generation Catalyzed by Oxygen-Vacancy-Rich One-Dimensional/Two-Dimensional W18O49/g-C3N4 Z-Scheme Heterostructures.

Z-scheme heterostructure-based photocatalysts consist of a reduction photocatalyst and an oxidation photocatalyst, enabling them to possess a high capacity for both reduction and oxidation. However, the coupling reaction between photocatalytic H2 generation through water reduction and sterilization using Z-scheme systems has been rarely reported. Herein, 1D W18O49 nanowires embedded over 2D g-C3N4 nanosheets are well-constructed as an integrated Z-scheme heterojunction. Experimental results and density functional theory calculations not only demonstrate the achievement of efficient interfacial charge separation and transport, leading to prolonged lifetime of photogenerated charge carriers, but also directly confirm the mechanism of Z-scheme charge transfer. As expected, the optimized W18O49/g-C3N4 nanostructure exhibits superior photocatalytic sterilization activity against Staphylococcus aureus as well as excellent H2 generation performance under visible-light irradiation (λ ≥ 420 nm). Due to its nontoxic nature, W18O49/g-C3N4 holds great potential in eradicating bacterial infections in living organisms.

Construction of Interlayer Coupling Diatomic Nanozyme with Peroxidase-Like and Photothermal Activities for Efficient Synergistic Antibacteria.

Pathogenic bacteria are the main cause of bacterial infectious diseases, which have posed a grave threat to public health. Single-atom nanozymes have emerged as promising candidates for antibacterial applications, but their activities need to be further improved. Considering diatomic nanozymes exhibit superior metal loading capacities and enhanced catalytic performance, a new interlayer coupling diatomic nanozyme (IC-DAN) is constructed by modulating the coordination environment in an atomic-level engineering. It is well demonstrated that IC-DAN exhibited superior peroxidase-mimetic activity in the presence of H2O2 to yield abundant ∙OH and possessed high photothermal conversion ability, which synergistically achieves efficient antibacterial therapy. Therefore, IC-DAN shows great potential used as antibacterial agent in clinic and this study open a new route to developing high-performance artificial enzymes.

The loading of Fe ions on N-doped carbon nanosheets to boost photocatalytic cascade for water disinfection.

The pervasive presence of pathogenic bacteria in water environment poses a serious threat to public health. Here, a photocatalytic cascade was developed to reveal great water disinfection. Firstly, N-doped carbon nanosheets (N-CNSs) about 30-50 nm in size were synthesized by a hydrothermal strategy. It revealed wide-spectrum photocatalysis for H2O2 generation via a typical two-step single-electron process. A Fenton agent (Fe ion) was loaded, N-CNSs-Fe can in-situ convert photocatalytic H2O2 into ·OH with high oxidation potential. Moreover, its Fenton active is three times greater than pure Fe2+ owing to electron enrichment from N-CNSs to Fe for Fe3+/Fe2+ cycle. Further investigation displayed that Fe loading also could decrease bad gap and promote charge separation to boost photocatalysis. In addition, N-CNSs-Fe possesses positive surface potential to exhibit strong interaction with negative bacteria, facilitating the capture. Therefore, the nanocomposite can effectively inactivate E. coli with a lethality rate of 99.7 % under stimulated sunlight irradiation. In addition, it also was employed to treat a complex lake water sample, revealing great antibacterial (95.1 %) and dye-decolored (92.3 %) efficiency at the same time. With novel biocompatibility and antibacterial ability, N-CNSs-Fe possessed great potential for water disinfection.

Remodeling Microenvironment for Implant-Associated Osteomyelitis by Dual Metal Peroxide.

Implant-associated osteomyelitis (IAOM) is characterized by bone infection and destruction; current therapy of antibiotic treatment and surgical debridement often results in drug resistance and bone defect. It is challenging to develop an antibiotic-free bactericidal and osteogenic-enhanced strategy for IAOM. Herein, an IAOM-tailored antibacterial and osteoinductive composite of copper (Cu)-strontium (Sr) peroxide nanoparticles (CSp NPs), encapsulated in polyethylene glycol diacrylate (PEGDA) (CSp@PEGDA), is designed. The dual functional CSp NPs display hydrogen peroxide (H2O2) self-supplying and Fenton catalytic Cu2+ ions' release, generating plenty of hydroxyl radical (•OH) in a pH-responsive manner for bacterial killing, while the released Sr2+ promotes the in vitro osteogenicity regarding cell proliferation, alkaline phosphatase activity, extracellular matrix calcification, and osteo-associated genes expression. The integration of Cu2+ and Sr2+ in CSp NPs together with the coated PEGDA hydrogel ensures the stable and sustainable ion release during short- and long-term periods. Benefitted from the injectablity and photo-crosslink ability, CSp@PEGDA is able to thoroughly fill the infectious site and gelate in situ for bacterial elimination and bone regeneration, which is verified through in vivo evaluation using a clinical-simulating IAOM mouse model. These favorable abilities of CSp@PEGDA precisely meet the multiple therapeutic needs and pave a promising way for implant-associated osteomyelitis treatment.