Explore the vast range of titles available.

Manganese is one of the most abundant elements on Earth. The oxidation of manganese has long been theorized 1 —yet has not been demonstrated 2 – 4 —to fuel the growth of chemolithoautotrophic microorganisms. Here we refine an enrichment culture that exhibits exponential growth dependent on Mn(II) oxidation to a co-culture of two microbial species. Oxidation required viable bacteria at permissive temperatures, which resulted in the generation of small nodules of manganese oxide with which the cells associated. The majority member of the culture—which we designate ‘ Candidatus Manganitrophus noduliformans’—is affiliated to the phylum Nitrospirae (also known as Nitrospirota), but is distantly related to known species of Nitrospira and Leptospirillum . We isolated the minority member, a betaproteobacterium that does not oxidize Mn(II) alone, and designate it Ramlibacter lithotrophicus . Stable-isotope probing revealed 13 CO 2 fixation into cellular biomass that was dependent upon Mn(II) oxidation. Transcriptomic analysis revealed candidate pathways for coupling extracellular manganese oxidation to aerobic energy conservation and autotrophic CO 2 fixation. These findings expand the known diversity of inorganic metabolisms that support life, and complete a biogeochemical energy cycle for manganese 5 , 6 that may interface with other major global elemental cycles. A co-culture of two newly identified microorganisms—‘ Candidatus Manganitrophus noduliformans’ and Ramlibacter lithotrophicus —exhibits exponential growth that is dependent on manganese(II) oxidation, demonstrating the viability of this metabolism for supporting life.

Phototherapy, known for its high selectivity, few side effects, strong controllability, and synergistic enhancement of combined treatments, is widely used in treating diseases like cervical cancer. In this study, hollow mesoporous manganese dioxide was used as a carrier to construct positively charged, poly(allylamine hydrochloride)-modified nanoparticles (NPs). The NP was efficiently loaded with the photosensitizer indocyanine green (ICG) via the addition of hydrogen phosphate ions to produce a counterion aggregation effect. HeLa cell membrane encapsulation was performed to achieve the final M-HMnO @ICG NP. In this structure, the HMnO carrier responsively degrades to release ICG in the tumor microenvironment, self-generates O for sensitization to ICG-mediated photodynamic therapy (PDT), and consumes GSH to expand the oxidative stress therapeutic effect [chemodynamic therapy (CDT) + PDT]. The ICG accumulated in tumor tissues exerts a synergistic PDT/photothermal therapy (PTT) effect through single laser irradiation, improving efficiency and reducing side effects. The cell membrane encapsulation increases nanomedicine accumulation in tumor tissues and confers an immune evasion ability. In addition, high local temperatures induced by PTT can enhance CDT. These properties of the NP enable full achievement of PTT/PDT/CDT and targeted effects. Mn can serve as a magnetic resonance imaging agent to guide therapy, and ICG can be used for photothermal and fluorescence imaging. After its intravenous injection, M-HMnO @ICG accumulated effectively at mouse tumor sites; the optimal timing of in-vivo laser treatment could be verified by near-infrared fluorescence, magnetic resonance, and photothermal imaging. The M-HMnO @ICG NPs had the best antitumor effects among treatment groups under near-infrared light conditions, and showed good biocompatibility. In this study, we designed a nano-biomimetic delivery system that improves hypoxia, responds to the tumor microenvironment, and efficiently loads ICG. It provides a new economical and convenient strategy for synergistic phototherapy and CDT for cervical cancer.

Manganese-based nanomaterials have piqued great interest in cancer nanotheranostics, owing to their excellent physicochemical properties. Here we report a facile wet-chemical synthesis of size-controllable, biodegradable, and metastable γ-phase manganese sulfide nanotheranostics, which is employed for tumor pH-responsive traceable gas therapy primed chemodynamic therapy (CDT), using bovine serum albumin (BSA) as a biological template (The final product was denoted as MnS@BSA). The as-prepared MnS@BSA can be degraded in response to the mildly acidic tumor microenvironment, releasing hydrogen sulfide (H S) for gas therapy and manganese ions for magnetic resonance imaging (MRI) and CDT. experiments validated the pH-responsiveness of MnS@BSA at pH 6.8 and both H S gas and •OH radicals were detected during its degradation. experiments showed efficiently tumor turn-on -weighted MRI, significantly suppressed tumor growth and greatly prolonged survival of tumor-bearing mice following intravenous administration of MnS@BSA. Our findings indicated that MnS@BSA nanotheranostics hold great potential for traceable H S gas therapy primed CDT of cancer.

Contrast agents (CAs) play a crucial role in high-quality magnetic resonance imaging (MRI) applications. At present, as a result of the Gd-based CAs which are associated with renal fibrosis as well as the inherent dark imaging characteristics of superparamagnetic iron oxide nanoparticles, Mn-based CAs which have a good biocompatibility and bright images are considered ideal for MRI. In addition, manganese oxide nanoparticles (MONs, such as MnO, MnO , Mn O , and MnO ) have attracted attention as T1-weighted magnetic resonance CAs due to the short circulation time of Mn(II) ion chelate and the size-controlled circulation time of colloidal nanoparticles. In this review, recent advances in the use of MONs as MRI contrast agents for tumor detection and diagnosis are reported, as are the advances in in vivo toxicity, distribution and tumor microenvironment-responsive enhanced tumor chemotherapy and radiotherapy as well as photothermal and photodynamic therapies.

The development of a highly efficient, low-toxicity, ultrasmall ferrite nanoparticle-based T contrast agent for high-resolution magnetic resonance imaging (MRI) is highly desirable. However, the correlations between the chemical compositions, T relaxivities, nano-bio interactions and toxicities remain unclear, which has been a challenge in optimizing the T contrast efficacy. : Ultrasmall (3 nm) manganese ferrite nanoparticles (Mn Fe O ) with different doping concentrations of the manganese ions (x = 0.32, 0.37, 0.75, 1, 1.23 and 1.57) were used as a model system to investigate the composition-dependence of the T contrast efficacy. The efficacy of liver-specific contrast-enhanced MRI was assessed through systematic multiple factor analysis, which included the T relaxivity, MRI contrast enhancement, pharmacokinetic profiles (blood half-life time, biodistribution) and biosafety evaluations ( cytotoxicity testing, blood routine examination, blood biochemistry testing and H&E staining to examine the liver). : With increasing Mn doping, the T relaxivities initially increased to their highest value of 10.35 mM s , which was obtained for Mn Fe O , and then the values decreased to 7.64 m M s , which was obtained for the Mn Fe O nanoparticles. Nearly linear increases in the MRI signals (ΔSNR) and biodistributions (accumulation in the liver) of the Mn Fe O nanoparticles were observed for increasing levels of Mn doping. However, both the and biosafety evaluations suggested that Mn Fe O nanoparticles with high Mn-doping levels (x > 1) can induce significant toxicity. : The systematic multiple factor assessment indicated that the Mn Fe O (x = 0.75-1) nanoparticles were the optimal T contrast agents with higher efficacies for liver-specific MRI than those of the other compositions of the Mn Fe O nanoparticles. Our work provides insight into the optimization of ultrasmall ferrite nanoparticle-based T contrast agents by tuning their compositions and promotes the translation of these ultrasmall ferrite nanoparticles for clinical use of high-performance contrast-enhanced MRI.

This study investigated the green synthesis of Zn-MnO nanocomposites via the fungus Penicillium rubens . Herein, the synthesized Zn-MnO nanocomposites were confirmed by UV-spectrophotometry with a top peak (370 nm). Transmission electron microscopy confirmed irregular particles with a spherical-like shape ranging from 25.13 to 36.21 nm. Numerous functional groups were detected on the surface of Zn-MnO nanocomposite via Fourier-transform infrared spectroscopy. X-Ray diffraction assay appeared that the synthesized Zn-MnO nanocomposites contained two different components, MnO (JCPDS 81-2261) and ZnO (JCPDS 36-1451), while energy dispersive X-ray spectra confirmed the occurrence of manganese, zinc, oxygen, and carbon in Zn-MnO nanocomposites. Zn-MnO nanocomposites demonstrated excellent suppress effect versus the growth of various bacteria namely Staphylococcus aureus , Methicillin-resistant S. aureus (MRSA), Salmonella typhi , and Klebsiella pneumoniae via agar well diffusion assays with inhibition areas of 36 ± 0.1, 25 ± 0.1, 27 ± 0.2, and 23 ± 0.2 mm, correspondingly. Alterations in the ultrastructure of the treated K. pneumoniae by Zn-MnO nanocomposite were recorded. Both the values of minimum inhibitory concentration (MIC) and minimum bactericidal concentration of Zn-MnO nanocomposite extended from 15.62 to 125 µg/mL employing the examined bacteria. The antibiofilm activity of Zn-MnO nanocomposites was 82.07, 75.43, 43.65, and 41.35% at 25% MIC, and 96.54, 93.0, 94.53, and 91.11% at 75% MIC against S. aureus , MRSA, K. pneumoniae , and S. typhi , respectively. At 25 to 75% MIC, Zn-MnO nanocomposites exhibited antihemolytic activity with the maximum activity of 96.3% at 75% MIC in the presence of MRSA. Extensive molecular docking studies were performed to identify the optimal location for manganese oxide and zinc oxide nanoclusters binding to MRSA. MnO-NPs and ZnO-NPs demonstrated inhibitory activity against the crystal structure of putative minohydrolase (PDB ID: 4EWT), methicillin acyl-penicillin binding protein 2a structure (PDB ID: 1MWU) and K2U bound crystal structure of class II peptide deformylase from MRSA (PDB ID: 6JFQ). The minimum binding energy was utilized to estimate the receptor’s binding site with NPs, providing additional understanding of the ways of action. Anti-inflammatory activity of Zn-MnO nanocomposites via cyclooxygenase-1 and cyclooxygenase-2 enzymes inhibition was documented with IC 50 doses of 20.81 ± 0.68 µg/mL and 35.87 ± 1.35 µg/mL, respectively. Based on these outcomes, it was concluded that Zn-MnO nanocomposites could be useful agents for the management of multidrug resistant bacterial pathogens and inflammation.

Manganese ferrite (MnFe2O4) magnetic nanoparticles were successfully prepared by a sol-gel self-combustion technique using iron nitrate and manganese nitrate, followed by calcination at 150 °C for 24 h. Calcined sample was systematically characterized by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), transmission electron microscopy (TEM), and vibrational sample magnetometry (VSM) in order to identify the crystalline phase, functional group, morphology, particle size, shape and magnetic behavior. It was observed that the resultant spinal ferrites obtained at low temperature exhibit single phase, nanoparticle size and good magnetic behavior. The study results have revealed the existence of a potent dose dependent cytotoxic effect of MnFe2O4 nanoparticles against 4T1 cell lines at varying concentrations with IC50 values of 210, 198 and 171 μg/mL after 24 h, 48 h and 72 h of incubation, respectively. Cells exposed to higher concentrations of nanoparticles showed a progressive increase of apoptotic and necrotic activity. Below 125 μg/mL concentration the nanoparticles were biocompatible with 4T1 cells.

Pathogen-host competition for manganese and intricate immunostimulatory pathways severely attenuates the efficacy of antibacterial immunotherapy against biofilm infections associated with orthopaedic implants. Herein, we introduce a spatiotemporal sono-metalloimmunotherapy (SMIT) strategy aimed at efficient biofilm ablation by custom design of ingenious biomimetic metal-organic framework (PCN-224)-coated MnO 2 -hydrangea nanoparticles (MnPM) as a metalloantibiotic. Upon reaching the acidic H 2 O 2 -enriched biofilm microenvironment, MnPM can convert abundant H 2 O 2 into oxygen, which is conducive to significantly enhancing the efficacy of ultrasound (US)-triggered sonodynamic therapy (SDT), thereby exposing bacteria-associated antigens (BAAs). Moreover, MnPM disrupts bacterial homeostasis, further killing more bacteria. Then, the Mn ions released from the degraded MnO 2 can recharge immune cells to enhance the cGAS-STING signaling pathway sensing of BAAs, further boosting the immune response and suppressing biofilm growth via biofilm-specific T cell responses. Following US withdrawal, the sustained oxygenation promotes the survival and migration of fibroblasts, stimulates the expression of angiogenic growth factors and angiogenesis, and neutralizes excessive inflammation. Our findings highlight that MnPM may act as an immune costimulatory metalloantibiotic to regulate the cGAS-STING signaling pathway, presenting a promising alternative to antibiotics for orthopaedic biofilm infection treatment and pro-tissue repair. Bacterial-host competition for micronutrients and inefficient immune responses undermine antimicrobial immunotherapy. Su et al . design an immunostimulatory metalloantibiotic and explore potential sono-metalloimmunotherapy (SMIT) for the treatment of clinical orthopaedic infections, in a murine model.

It is necessary to control the emissions of toluene, which is hazardous to both human health and the atmosphere environment and has been classified as a priority pollutant. Manganese oxide-based (Mn-based) catalysts have received increased attention due to their high catalytic performance, good physicochemical characteristic, availability in various crystal structures and morphologies, and being environmentally friendly and low cost. These catalysts can be classified into five categories, namely single manganese oxide, Mn-based composite oxides, Mn-based special oxides, supported Mn-based oxides, and Mn-based monoliths. This review focused on the recent progress on the five types of Mn-based catalysts for catalytic removal of toluene at low temperature and further systematically summarized the strategies improving catalysts, including improving synthetic methods, incorporating MnO x with other metal oxides, depositing Mn-based oxides on proper supports, and tuning the supports. Moreover, the effect of coexisting components, the reaction kinetics, and the oxidation mechanisms toward the removal of toluene were also discussed. Finally, the future research direction of this field was presented.

Reperfusion injury is still a major challenge that impedes neuronal survival in ischemic stroke. However, the current clinical treatments are remained on single pathological process, which are due to lack of comprehensive neuroprotective effects. Herein, a macrophage‐disguised honeycomb manganese dioxide (MnO2) nanosphere loaded with fingolimod (FTY) is developed to salvage the ischemic penumbra. In particular, the biomimetic nanoparticles can accumulate actively in the damaged brain via macrophage‐membrane protein‐mediated recognition with cell adhesion molecules that are overexpressed on the damaged vascular endothelium. MnO2 nanosphere can consume excess hydrogen peroxide (H2O2) and convert it into desiderated oxygen (O2), and can be decomposed in acidic lysosome for cargo release, so as to reduce oxidative stress and promote the transition of M1 microglia to M2 type, eventually reversing the proinflammatory microenvironment and reinforcing the survival of damaged neuron. This biomimetic nanomedicine raises new strategy for multitargeted combined treatment of ischemic stroke. Macrophage‐disguised FTY‐loaded MnO2 nanoparticles (Ma@(MnO2+FTY)) are engineered to salvage the ischemic penumbra. Nanoparticles can accumulate actively in the ischemic region to protect neurons directly via consuming ROS and generating O2. In addition, the nanoparticles can also reverse the proinflammatory microenvironment by promoting the phenotypic transition of microglia through multiple signaling pathways, increasing the protection effects on damaged neurons.