Chemodynamic PtMn Nanocubes for Effective Photothermal ROS Storm a Key Anti-Tumor Therapy in-vivo.

Background: Chemodynamic therapy (CDT) is a new treatment approach that is triggered by endogenous stimuli in specific intracellular conditions for generating hydroxyl radicals. However, the efficiency of CDT is severely limited by Fenton reaction agents and harsh reaction conditions. Methods: Bimetallic PtMn nanocubes were rationally designed and simply synthesized through a one-step high-temperature pyrolysis process by controlling both the nucleation process and the subsequent crystal growth stage. The polyethylene glycol was modified to enhance biocompatibility. Results: Benefiting from the alloying of Pt nanocubes with Mn doping, the structure of the electron cloud has changed, resulting in different degrees of the shift in electron binding energy, resulting in the increasing of Fenton reaction activity. The PtMn nanocubes could catalyze endogenous hydrogen peroxide to toxic hydroxyl radicals in mild acid. Meanwhile, the intrinsic glutathione (GSH) depletion activity of PtMn nanocubes consumed GSH with the assistance of Mn3+/Mn2+. Upon 808 nm laser irradiation, mild temperature due to the surface plasmon resonance effect of Pt metal can also enhance the Fenton reaction. Conclusion: PtMn nanocubes can not only destroy the antioxidant system via efficient reactive oxygen species generation and continuous GSH consumption but also propose the photothermal effect of noble metal for enhanced Fenton reaction activity.

Arthrospira platensis enriched with Cr(III), Mg(II), and Mn(II) ions improves insulin sensitivity and reduces systemic inflammation in equine metabolic affected horses.

Equine metabolic syndrome (EMS) is a critical endocrine condition in horses, characterized by hyperinsulinemia, hyperlipidemia, and insulin resistance, posing a significant threat to their health. This study investigates the efficacy of supplementing EMS-affected horses with Arthrospira platensis enriched with Cr(III), Mg(II), and Mn(II) ions using biosorption process in improving insulin sensitivity and glucose tolerance, reducing inflammation, and mitigating obesity-related fat accumulation. Our results demonstrate that Arthrospira supplementation reduces baseline insulin and glucose levels, contributing to decreased adipose tissue inflammation. Furthermore, Arthrospira supplementation results in a decrease in body weight and improvements in overall body condition scores and cresty neck scores. Additionally, administration of Arthrospira leads to reduced levels of triglycerides and aspartate aminotransferase, indicating a decrease in hepatic adiposity and inflammation. These findings suggest that Arthrospira, enriched with essential micro- and macroelements, can be an advanced feed additive to enhance insulin sensitivity, promote weight reduction, and alleviate inflammatory processes, thereby improving the overall condition of horses affected by EMS. The use of Arthrospira as a feed additive has the potential to complement conventional management strategies for EMS.

Manganese exposure from spring and well waters in the Shenandoah Valley: interplay of aquifer lithology, soil composition, and redox conditions.

Manganese (Mn) is of particular concern in groundwater, as low-level chronic exposure to aqueous Mn concentrations in drinking water can result in a variety of health and neurodevelopmental effects. Much of the global population relies on drinking water sourced from karst aquifers. Thus, we seek to assess the relative risk of Mn contamination in karst by investigating the Shenandoah Valley, VA region, as it is underlain by both karst and non-karst aquifers and much of the population relies on water wells and spring water. Water and soil samples were collected throughout the Shenandoah Valley, to supplement pre-existing well water and spring data from the National Water Information System and the Virginia Household Water Quality Program, totaling 1815 wells and 119 springs. Soils were analyzed using X-ray fluorescence and Mn K-Edge X-ray absorption near-edge structure spectroscopy. Factors such as soil type, soil geochemistry, and aquifer lithology were linked with each location to determine if correlations exist with aqueous Mn concentrations. Analyzing the distribution of Mn in drinking water sources suggests that water wells and springs within karst aquifers are preferable with respect to chronic Mn exposure, with < 4.9% of wells and springs in dolostone and limestone aquifers exceeding 100 ppb Mn, while sandstone and shale aquifers have a heightened risk, with > 20% of wells exceeding 100 ppb Mn. The geochemistry of associated soils and spatial relationships to various hydrologic and geologic features indicates that water interactions with aquifer lithology and soils contribute to aqueous Mn concentrations. Relationships between aqueous Mn in spring waters and Mn in soils indicate that increasing aqueous Mn is correlated with decreasing soil Mn(IV). These results point to redox conditions exerting a dominant control on Mn in this region.

Dual-channel fluorescent sensors based on chitosan-coated Mn-doped ZnS micromaterials to detect ampicillin.

The global threat of antibiotic resistance has increased the importance of the detection of antibiotics. Conventional methods to detect antibiotics are time-consuming and require expensive specialized equipment. Here, we present a simple and rapid biosensor for detecting ampicillin, a commonly used antibiotic. Our method is based on the fluorescent properties of chitosan-coated Mn-doped ZnS micromaterials combined with the ß-lactamase enzyme. The biosensors exhibited the highest sensitivity in a linear working range of 13.1-72.2 pM with a limit of detection of 8.24 pM in deionized water. In addition, due to the biological specificity of ß-lactamase, the proposed sensors have demonstrated high selectivity over penicillin, tetracycline, and glucose through the enhancing and quenching effects at wavelengths of 510 nm and 614 nm, respectively. These proposed sensors also showed promising results when tested in various matrices, including tap water, bottled water, and milk. Our work reports for the first time the cost-effective (Mn:ZnS)Chitosan micromaterial was used for ampicillin detection. The results will facilitate the monitoring of antibiotics in clinical and environmental contexts.

Facile Synthesis of Rigid Binuclear Manganese Complexes for Magnetic Resonance Angiography and SLC39A14-Mediated Hepatic Imaging.

Manganese(II)-based contrast agents (MBCAs) are potential candidates for gadolinium-free enhanced magnetic resonance imaging (MRI). In this work, a rigid binuclear MBCA (Mn2-PhDTA2) with a zero-length linker was developed via facile synthetic routes, while the other dimer (Mn2-TPA-PhDTA2) with a longer rigid linker was also synthesized via more complex steps. Although the molecular weight of Mn2-PhDTA2 is lower than that of Mn2-TPA-PhDTA2, their T1 relaxivities are similar, being increased by over 71% compared to the mononuclear Mn-PhDTA. In the presence of serum albumin, the relaxivity of Mn2-PhDTA2 was slightly lower than that of Mn2-TPA-PhDTA2, possibly due to the lower affinity constant. The transmetalation reaction with copper(II) ions confirmed that Mn2-PhDTA2 has an ideal kinetic inertness with a dissociation half-life of approximately 10.4 h under physiological conditions. In the variable-temperature 17O NMR study, both Mn-PhDTA and Mn2-PhDTA2 demonstrated a similar estimated q close to 1, indicating the formation of monohydrated complexes with each manganese(II) ion. In addition, Mn2-PhDTA2 demonstrated a superior contrast enhancement to Mn-PhDTA in in vivo vascular and hepatic MRI and can be rapidly cleared through a dual hepatic and renal excretion pattern. The hepatic uptake mechanism of Mn2-PhDTA2 mediated by SLC39A14 was validated in cellular uptake studies.

Child and Adolescent Manganese Biomarkers and Adolescent Postural Balance in Marietta CARES Cohort Participants.

BACKGROUND: Manganese (Mn) plays a significant role in both human health and global industries. Epidemiological studies of exposed populations demonstrate a dose-dependent association between Mn and neuromotor effects ranging from subclinical effects to a clinically defined syndrome. However, little is known about the relationship between early life Mn biomarkers and adolescent postural balance. OBJECTIVES: This study investigated the associations between childhood and adolescent Mn biomarkers and adolescent postural balance in participants from the longitudinal Marietta Communities Actively Researching Exposures Study (CARES) cohort. METHODS: Participants were recruited into CARES when they were 7-9 y old, and reenrolled at 13-18 years of age. At both time points, participants provided samples of blood, hair, and toenails that were analyzed for blood Mn and lead (Pb), serum cotinine, hair Mn, and toenail Mn. In adolescence, participants completed a postural balance assessment. Greater sway indicates postural instability (harmful effect), whereas lesser sway indicates postural stability (beneficial effect). Multivariable linear regression models were conducted to investigate the associations between childhood and adolescent Mn biomarkers and adolescent postural balance adjusted for age, sex, height-weight ratio, parent/caregiver intelligence quotient, socioeconomic status, blood Pb, and serum cotinine. RESULTS: CARES participants who completed the adolescent postural balance assessment (n=123) were 98% White and 54% female and had a mean age of 16 y (range: 13-18 y). In both childhood and adolescence, higher Mn biomarker concentrations were significantly associated with greater adolescent sway measures. Supplemental analyses revealed sex-specific associations; higher childhood Mn biomarker concentrations were significantly associated with greater sway in females compared with males. DISCUSSION: This study found childhood and adolescent Mn biomarkers were associated with subclinical neuromotor effects in adolescence. This study demonstrates postural balance as a sensitive measure to assess the association between Mn biomarkers and neuromotor function. https://doi.org/10.1289/EHP13381.

Concentrations of Bioelements (Zn, Cu, Fe, Cr, Mg, Mn) in Serum and Bone Tissue of Aging Men Undergoing Hip Arthroplasty: Implications for Erectile Dysfunction.

Background: Erectile dysfunction (ED) stands out as one of the most prevalent sexual disorders in men, with its incidence progressively escalating with age. As delineated by the International Consultation Committee for Sexual Medicine on Definitions/Epidemiology/Risk Factors for Sexual Dysfunction, the prevalence of ED among men under 40 years is estimated to be within the range of 1-10%. The aim of this study was to determine the relationship between the concentration of bioelements (Zn, Cu, Fe, Cr, Mg, and Mn) in the serum and bone tissue and the concentration of selected hormones in men with and without erectile dysfunction. Materials and methods: The retrospective cohort study included 152 men who underwent total hip arthroplasty for hip osteoarthritis at the Department of Orthopaedic Traumatology and Musculoskeletal Oncology at the Pomeranian Medical University in Szczecin. Certain exclusion criteria were applied to ensure the integrity of the study. These included individuals with diabetes, a history of cancer, alcohol abuse, liver or kidney failure, New York Heart Association (NYHA) class III or IV heart failure, and those taking medications that affect bone metabolism, such as mineral supplements, neuroleptics, chemotherapeutic agents, immunosuppressants, corticosteroids, or antidepressants. Patients with hypogonadism or infertility were excluded from the study. Results: The study showed an association between bioT concentrations and Cu concentrations in both patients with and without erectile dysfunction. A correlation between bioactive testosterone and Cr concentrations was also observed in both groups. Patients with erectile dysfunction showed a relationship between bioT concentration and Zn concentration, TT concentration and Mn concentration, FT concentration and Zn concentration, and E2 concentration and Cr concentration. An analysis of elemental concentrations in bone tissue showed an association between FT and Mg and Mn concentrations, but only in patients with erectile dysfunction. In patients without erectile dysfunction, a correlation was observed between FT and Cu concentrations. A correlation was also observed between bioT concentrations and Mg, Mn, and Zn concentrations, but only in patients with erectile dysfunction. In patients without erectile dysfunction, a correlation was observed between bioT and Cu concentrations. Conclusions: Studying the relationship between the concentration of bioelements (Zn, Cu, Fe, Cr, Mg, and Mn) in the serum and bone tissue and the concentration of selected hormones in men may be important in explaining the etiology of the problem. The study of the concentration of Zn and Cu in bone tissue and serum showed that these two elements, regardless of the place of accumulation, may be related to the concentration of androgens in men.

Three musketeers of PDA-based MRI contrasting and therapy.

Polydopamine (PDA) stands as a versatile material explored in cancer nanomedicine for its unique properties, offering opportunities for multifunctional drug delivery platforms. This study explores the potential of utilizing a one-pot synthesis to concurrently integrate Fe, Gd and Mn ions into porous PDA-based theranostic drug delivery platforms called Ferritis, Gadolinis and Manganis, respectively. Our investigation spans the morphology, magnetic properties, photothermal characteristics and cytotoxicity profiles of those potent nanoformulations. The obtained structures showcase a spherical morphology, robust magnetic response and promising photothermal behaviour. All of the presented nanoparticles (NPs) display pronounced paramagnetism, revealing contrasting potential for MRI imaging. Relaxivity values, a key determinant of contrast efficacy, demonstrated competitive or superior performance compared to established, used contrasting agents. These nanoformulations also exhibited robust photothermal properties under near infra-red irradiation, showcasing their possible application for photothermal therapy of cancer. Our findings provide insights into the potential of metal-doped PDA NPs for cancer theranostics.

Plant-microbe involvement: How manganese achieves harmonious nitrogen-removal and carbon-reduction in constructed wetlands.

Carbon deficits in inflow frequently lead to inefficient nitrogen removal in constructed wetlands (CWs) treating tailwater. Solid carbon sources, commonly employed to enhance denitrification in CWs, increase carbon emissions. In this study, MnO2 was incorporated into polycaprolactone substrates within CWs, significantly enhancing NH4+-N and NO3--N removal efficiencies by 48.26-59.78 % and 96.84-137.23 %, respectively. These improvements were attributed to enriched nitrogen-removal-related enzymes and increased plant absorption. Under high nitrogen loads (9.55 ± 0.34 g/m3/d), emissions of greenhouse gases (CO2, CH4, and N2O) decreased by 147.23-202.51 %, 14.53-86.76 %, and 63.36-87.36 %, respectively. N2O emissions were reduced through bolstered microbial nitrogen removal pathways by polycaprolactone and MnO2. CH4 accumulation was mitigated by the increased methanotrophs and dampened methanogenesis, modulated by manganese. Additionally, manganese-induced increases in photosynthetic pigment contents (21.28-64.65 %) fostered CO2 sequestration through plant photosynthesis. This research provides innovative perspectives on enhancing nitrogen removal and reducing greenhouse gas emissions in constructed wetlands with polymeric substrates.

The non-linear associations between blood manganese level and sarcopenia in patients undergoing maintenance hemodialysis: A multicenter cross-sectional study.

BACKGROUND AND AIMS: Manganese (Mn), a vital element in energy metabolism, is predominantly stored in skeletal muscles and plays a crucial role in muscle function and strength. Patients on maintenance hemodialysis (MHD) often experience muscle wasting due to metabolic disruption and inflammation. This study aimed to explore the relationship between blood Mn levels and sarcopenia in a patient population. METHODS: In this multicenter cross-sectional study, conducted from March 2021 to March 2022, 386 patients on MHD from three medical centers were included. Blood Mn levels were measured using inductively coupled plasma mass spectrometry, and body composition was assessed post-dialysis using bioelectrical impedance analysis. Grip strength was measured using a digital dynamometer. The patients were categorized into groups with and without sarcopenia. Using a generalized additive model to fit a smooth curve, we employed a generalized linear model to identify the optimal inflection point and explore the threshold effect after discovering a segmented relationship. Subsequently, a binary logistic regression analysis was conducted to investigate the relationship between blood manganese levels and the risk of sarcopenia, with adjustments made for potential confounding factors. RESULTS: A negative correlation was observed between blood Mn levels and sarcopenia-related parameters (Appendicular Skeletal Muscle Mass Index and grip strength) in Spearman's correlation analysis (both P < 0.05). After adjusting for confounding factors, a nonlinear association was identified. When blood Mn was ≤ 10.6 µg/L, the increase in sarcopenia was not statistically significant (P > 0.05). Conversely, when blood Mn exceeded 10.6 µg/L, each 1 µg/L increase raised the risk of sarcopenia by 0.1 times. Considering confounders, multivariate binary logistic regression confirmed an independent association between elevated blood Mn levels and sarcopenia. CONCLUSION: This study revealed an independent association between elevated blood Mn levels (> 10.6 µg/L) and sarcopenia in patients undergoing MHD. These findings emphasize the importance of understanding the Mn metabolism in the context of muscle health in this patient population. Further research is warranted to explore the underlying mechanisms and potential interventions for mitigating sarcopenia in patients with elevated blood Mn levels undergoing MHD.

R3 strain and Fe-Mn modified biochar reduce Cd absorption capacity of roots and available Cd content of soil by affecting rice rhizosphere and endosphere key flora.

Microorganisms have a significant role in regulating the absorption and transportation of Cd in the soil-plant system. However, the mechanism by which key microbial taxa play a part in response to the absorption and transportation of Cd in rice under Cd stress requires further exploration. In this study, the cadmium-tolerant endophytic bacterium Herbaspirillum sp. R3 (R3) and Fe-Mn-modified biochar (Fe-Mn) were, respectively, applied to cadmium-contaminated rice paddies to investigate the effects of key bacterial taxa in the soil-rice system on the absorption and transportation of Cd in rice under different treatments. The results showed that both R3 and Fe-Mn treatments considerably decreased the content of cadmium in roots, stems and leaves of rice at the peak tillering stage by 17.24-49.28% in comparison to the control (CK). The cadmium content reduction effect of R3 treatment is better than that of Fe-Mn treatment. Further analysis revealed that the key bacterial taxa in rice roots under R3 treatment were Sideroxydans and Actinobacteria, and that their abundance showed a substantial positive correlation and a significant negative correlation with the capacity of rice roots to assimilate Cd from the surroundings, respectively. The significant increase in soil pH under Fe-Mn treatment, significant reduction in the relative abundances of Acidobacteria, Verrucomicrobia, Subdivision3 genera incertae sedis, Sideroxydans, Geobacter, Gp1, and Gp3, and the significant increase in the relative abundance of Thiobacillus among the soil bacterial taxa may be the main reasons for the decrease in available Cd content of the soil. In addition, both the R3 and Fe-Mn treatments showed some growth-promoting effects on rice, which may be related to their promotion of transformations of soil available nutrients. This paper describes the possible microbial mechanisms by which strain R3 and Fe-Mn biochar reduce Cd uptake in rice, providing a theoretical basis for the remediation of Cd contamination in rice and soil by utilizing key microbial taxa.

Neurotoxicity of manganese via ferroptosis induced by redox imbalance and iron overload.

Manganese (Mn) is an essential trace element for maintaining bodily functions. Excessive exposure to Mn can pose serious health risks to humans and animals, particularly to the nervous system. While Mn has been implicated as a neurotoxin, the exact mechanism of its toxicity remains unclear. Ferroptosis is a form of programmed cell death that results from iron-dependent lipid peroxidation. It plays a role in various physiological and pathological cellular processes and may be closely related to Mn-induced neurotoxicity. However, the mechanism of ferroptosis in Mn-induced neurotoxicity has not been thoroughly investigated. Therefore, this study aims to investigate the role and mechanism of ferroptosis in Mn-induced neurotoxicity. Using bioinformatics, we identified significant changes in genes associated with ferroptosis in Mn-exposed animal and cellular models. We then evaluated the role of ferroptosis in Mn-induced neurotoxicity at both the animal and cellular levels. Our findings suggest that Mn exposure causes weight loss and nervous system damage in mice. In vitro and in vivo experiments have shown that exposure to Mn increases malondialdehyde, reactive oxygen species, and ferrous iron, while decreasing glutathione and adenosine triphosphate. These findings suggest that Mn exposure leads to a significant increase in lipid peroxidation and disrupts iron metabolism, resulting in oxidative stress injury and ferroptosis. Furthermore, we assessed the expression levels of proteins and mRNAs related to ferroptosis, confirming its significant involvement in Mn-induced neurotoxicity.

[52Mn]Mn-BPPA-Trastuzumab: A Promising HER2-Specific PET Radiotracer.

This study aimed to develop a novel radiotracer using trastuzumab and the long-lived [52Mn]Mn isotope for HER2-targeted therapy selection and monitoring. A new Mn(II) chelator, BPPA, synthesized from a rigid bispyclen platform possessing a picolinate pendant arm, formed a stable and inert Mn(II) complex with favorable relaxation properties. BPPA was converted into a bifunctional chelator (BFC), conjugated to trastuzumab, and labeled with [52Mn]Mn isotope. In comparison to DOTA-GA-trastuzumab, the BPPA-trastuzumab conjugate exhibits a labeling efficiency with [52Mn]Mn approximately 2 orders of magnitude higher. In female CB17 SCID mice bearing 4T1 (HER2-) and MDA-MB-HER2+ (HER2+) xenografts, [52Mn]Mn-BPPA-trastuzumab demonstrated superior uptake in HER2+ cells on day 3, with a 3-4 fold difference observed on day 7. Overall, the hexadentate BPPA chelator proves to be exceptional in binding Mn(II). Upon coupling with trastuzumab as a BFC ligand, it becomes an excellent imaging probe for HER2-positive tumors. [52Mn]Mn-BPPA-trastuzumab enables an extended imaging time window and earlier detection of HER2-positive tumors with superior tumor-to-background contrast.

Genomic characteristics of nine Nitrospirota metagenome-assembled genomes in deep-sea sediments from East Pacific polymetallic nodules zone.

Previously studies have reported that MAGs (Metagenome-assembled genomes) belong to "Candidatus Manganitrophaceae" of phylum Nitrospirota with chemolithoautotrophic manganese oxidation potential exist in freshwater and hydrothermal environments. However, Nitrospirota members with chemolithoautotrophic manganese oxidation potential have not been reported in other marine environments. Through metagenomic sequencing, assembly and binning, nine metagenome-assembled genomes belonging to Nitrospirota are recovered from sediment of different depths in the polymetallic nodule area. Through the key functional genes annotation results, we find that these Nitrospirota have limited potential to oxidize organic carbon because of incomplete tricarboxylic acid cycle and most of them (6/9) have carbon dioxide fixation potential through different pathway (rTCA, WL or CBB). One MAG belongs to order Nitrospirales has the potential to use manganese oxidation to obtain energy for carbon fixation. In addition to manganese ions, the oxidation of inorganic nitrogen, sulfur, hydrogen and carbon monoxide may also provide energy for the growth of these Nitrospirota. In addition, different metal ion transport systems can help those Nitrospirota to resist heavy metal in sediment. Our work expands the understanding of the metabolic potential of Nitrospirota in sediment of polymetallic nodule region and may contributes to promoting the study of chemolithoautotrophic manganese oxidation.

Immobilized Dipeptidase in Manganese Ion-Loaded Polyethylenimine-Induced Calcium Phosphate Nanocrystals for Carnosine Synthesis.

Carnosine is a natural bioactive dipeptide with important physiological functions widely used in food and medicine. Dipeptidase (PepD) from Serratia marcescens can catalyze the reverse hydrolytic reaction of ß-alanine with l-histidine to synthesize carnosine in the presence of Mn2+. However, it remains challenging to practice carnosine biosynthesis due to the low activity and high cost of the enzyme. Therefore, the development of biocatalysts with high activity and stability is of significance for carnosine synthesis. Here, we proposed to chelate Mn2+ to polyethylenimine (PEI) that induced rapid formation of calcium phosphate nanocrystals (CaP), and Mn-PEI@CaP was used for PepD immobilization via electrostatic interaction. Mn-PEI@CaP as the carrier enhanced the stability of the immobilized enzyme. Moreover, Mn2+ loaded in the carrier acted as an in situ activator of the immobilized PepD for facilitating the biocatalytic process of carnosine synthesis. The as-prepared immobilized enzyme (PepD-Mn-PEI@CaP) kept similar activity with free PepD plus Mn2+ (activity recovery, 102.5%), while exhibiting elevated thermal stability and pH tolerance. Moreover, it exhibited about two times faster carnosine synthesis than the free PepD system. PepD-Mn-PEI@CaP retained 86.8% of the original activity after eight cycles of batch catalysis without the addition of free Mn2+ ions during multiple cycles. This work provides a new strategy for the co-immobilization of PepD and Mn2+, which greatly improves the operability of the biocatalysis and demonstrates the potential of the immobilized PepD system for efficient carnosine synthesis.

Unraveling the Role of Humic Acid in the Oxidation of Phenolic Contaminants by Soluble Manganese Oxo-Anions.

Humic acid (HA) is ubiquitous in natural aquatic environments and effectively accelerates decontamination by permanganate (Mn(VII)). However, the detailed mechanism remains uncertain. Herein, the intrinsic mechanisms of HA's impact on phenolics oxidation by Mn(VII) and its intermediate manganese oxo-anions were systematically studied. Results suggested that HA facilitated the transfer of a single electron from Mn(VII), resulting in the sequential formation of Mn(VI) and Mn(V). The formed Mn(V) was further reduced to Mn(III) through a double electron transfer process by HA. Mn(III) was responsible for the HA-boosted oxidation as the active species attacking pollutants, while Mn(VI) and Mn(V) tended to act as intermediate species due to their own instability. In addition, HA could serve as a stabilizer to form a complex with produced Mn(III) and retard the disproportionation of Mn(III). Notably, manganese oxo-anions did not mineralize HA but essentially changed its composition. According to the results of Fourier-transform ion cyclotron resonance mass spectrometry and the second derivative analysis of Fourier-transform infrared spectroscopy, we found that manganese oxo-anions triggered the decomposition of C-H bonds on HA and subsequently produced oxygen-containing functional groups (i.e., C-O). This study might shed new light on the HA/manganese oxo-anion process.

Associations between blood manganese levels and sarcopenia in adults: insights from the National Health and Nutrition Examination Survey.

Background: While increasing concerns arise about the health effects of environmental pollutants, the relationship between blood manganese (Mn) and sarcopenia has yet to be fully explored in the general population. Objective: This study aims to investigate the association between blood manganese (Mn) levels and sarcopenia in adults. Methods: In our study, we evaluated 8,135 individuals aged 18-59 years, utilizing data from the National Health and Nutrition Examination Survey (NHANES) spanning 2011 to 2018. We employed generalized additive model (GAM) to discern potential non-linear relationships and utilized the two-piecewise linear regression model to probe the association between blood Mn levels and sarcopenia. Results: After adjusting for potential confounders, we identified non-linear association between blood Mn levels and sarcopenia, with an inflection point at 13.45 µg/L. The effect sizes and the confidence intervals on the left and right sides of the inflection point were 1.006 (0.996 to 1.048) and 1.082 (1.043 to 1.122), respectively. Subgroup analysis showed that the effect sizes of blood Mn on sarcopenia have significant differences in gender and different BMI groups. Conclusion: Our results showed that a reverse U-shaped curve between blood Mn levels and sarcopenia, with an identified the inflection point at blood Mn level of 13.45 µg/L.

Outer membrane vesicle-wrapped manganese nanoreactor for augmenting cancer metalloimmunotherapy through hypoxia attenuation and immune stimulation.

Tumor hypoxia, high oxidative stress, and low immunogenic create a deep-rooted immunosuppressive microenvironment, posing a major challenge to the therapeutic efficiency of cancer immunotherapy for solid tumor. Herein, an intelligent nanoplatform responsive to the tumor microenvironment (TME) capable of hypoxia relief and immune stimulation has been engineered for efficient solid tumor immunotherapy. The MnO2@OxA@OMV nanoreactor, enclosing bacterial-derived outer membrane vesicles (OMVs)-wrapped MnO2 nanoenzyme and the immunogenic cell death inducer oxaliplatin (OxA), demonstrated intrinsic catalase-like activity within the TME, which effectively catalyzed the endogenous H2O2 into O2 to enable a prolonged oxygen supply, thereby alleviating the tumor's oxidative stress and hypoxic TME, and expediting OxA release. The combinational action of OxA-caused ICD effect and Mn2+ from nanoreactor enabled the motivation of the cGAS-STING pathway to significantly improve the activation of STING and dendritic cells (DCs) maturation, resulting in metalloimmunotherapy. Furthermore, the immunostimulant OMVs played a crucial role in promoting the infiltration of activated CD8+T cells into the solid tumor. Overall, the nanoreactor offers a robust platform for solid tumor treatment, highlighting the significant potential of combining relief from tumor hypoxia and immune stimulation for metalloimmunotherapy. STATEMENT OF SIGNIFICANCE: A tailor-made nanoreactor was fabricated by enclosing bacterial-derived outer membrane vesicles (OMVs) onto MnO2 nanoenzyme and loading with immunogenic cell death inducer oxaliplatin (OxA) for tumor metalloimmunotherapy. The nanoreactor possesses intrinsic catalase-like activity within the tumor microenvironment, which effectively enabled a prolonged oxygen supply by catalyzing the conversion of endogenous H2O2 into O2, thereby alleviating tumor hypoxia and expediting OxA release. Furthermore, the TME-responsive release of nutritional Mn2+ sensitized the cGAS-STING pathway and collaborated with OxA-induced immunogenic cell death (ICD). Combing with immunostimulatory OMVs enhances the uptake of nanoreactors by DCs and promotes the infiltration of activated CD8+T cells. This nanoreactor offers a robust platform for solid tumor treatment, highlighting the significant potential of combining relief from tumor hypoxia and immune stimulation for metalloimmunotherapy.

A nascent riboswitch helix orchestrates robust transcriptional regulation through signal integration.

Widespread manganese-sensing transcriptional riboswitches effect the dependable gene regulation needed for bacterial manganese homeostasis in changing environments. Riboswitches - like most structured RNAs - are believed to fold co-transcriptionally, subject to both ligand binding and transcription events; yet how these processes are orchestrated for robust regulation is poorly understood. Through a combination of single-molecule and bulk approaches, we discover how a single Mn2+ ion and the transcribing RNA polymerase (RNAP), paused immediately downstream by a DNA template sequence, are coordinated by the bridging switch helix P1.1 in the representative Lactococcus lactis riboswitch. This coordination achieves a heretofore-overlooked semi-docked global conformation of the nascent RNA, P1.1 base pair stabilization, transcription factor NusA ejection, and RNAP pause extension, thereby enforcing transcription readthrough. Our work demonstrates how a central, adaptable RNA helix functions analogous to a molecular fulcrum of a first-class lever system to integrate disparate signals for finely balanced gene expression control.

A method for studying the influence of Mn oxyhydroxides on the trace element content of aquatic bryophytes.

The main objective of this study was to develop and test a method of separating externally deposited Mn oxyhydroxides and co-precipitated elements from samples of aquatic moss (the moss Fontinalis antipyretica). The method, which uses 0.1 M hydroxylamine to dissolve the oxyhydroxides, was tested with samples collected in rivers with slightly acidic, well­oxygenated waters, where high rates of Mn precipitation occur. The method was effective (it extracted up to 84 % of the Mn) and selective (Fe oxyhydroxides were not extracted). The elements Ba, Cd, Zn and Ni were associated with the Mn oxyhydroxides, while Al, As, Cr, Cu, Fe, Hg and Pb were not. Deposition of Mn therefore increased the concentration of some elements in the moss samples. However, as Mn precipitation depends on Eh and pH, which are independent of the concentrations of the elements in water, the relationship between water and moss element concentrations is not clear (i.e. the data are noisy). This is a problem in biomonitoring studies, which assume a close relationship between element concentrations in moss and water. The value of the proposed extraction method is that it can be used to correct the effect of Mn deposition. We present an example of this correction applied to the Cd concentrations in the test data. We found that the noise introduced by the Mn, including age-related effects (observed by comparing concentrations in 0-2.5 and 2.2-5.0 cm sections from the shoot apex), can be reduced. Additionally, the correction revealed recent increases in Cd concentrations in one site that were not observed in the uncorrected data. Another finding of interest was the low content of total Mn and different extractability (of most elements) observed in moss samples collected in alkaline waters. Finally, we discuss how future studies designed for different environmental scenarios can benefit from application of the proposed method.