Potential Growth of Anammox Bacteria under Aerobic Conditions.

Anammox bacteria are obligate anaerobic bacteria that exist widely in nature with sufficient amounts of dissolved oxygen. However, whether anammox bacteria can grow under aerobic conditions remains unclear. In this study, we found that the production of nitrate in the anammox system under aerobic conditions was significantly higher than that under anaerobic conditions without total nitrogen loss. Anammox bacteria can grow by oxidizing nitrite and dehydrogenating hydrazine to produce electrons for carbon fixation. The hydrazine dehydrogenase in anammox bacteria was inhibited under aerobic conditions, and the nitrite oxidoreductase transcription expression of anammox bacteria increased by 2.7 times compared to that under anaerobic conditions, which was the main way for anammox bacteria perform carbon fixation. DNA-stable isotope probing with 13C bicarbonate found the existence of anammox bacteria with 13C isotopes in aerobic cultivation, further proving that anammox bacteria can grow under aerobic condition. More than half of the pathways in glycolysis, the Wood-Ljungdahl pathway, and the tricarboxylic acid cycle were upregulated in anammox bacteria in aerobic condition. Large amounts of bacterioferritins are the important antioxidative enzymes in anammox bacteria in the aerobic environment, which contributes to their stronger oxygen adaptation than other anaerobes. This study expands our understanding of the growth mechanism of anammox bacteria as well as the oxygen adaptation strategies of obligate anaerobic bacteria.

The potential of nanosystems in disrupting adenosine signaling pathways for tumor immunotherapy.

INTRODUCTION: Adenosine (ADO) is a naturally occurring nucleoside primarily synthesized through the hydrolysis of extracellular adenosine triphosphate. Within the tumor microenvironment, ADO levels substantially increase, resulting in suppressed immune responses. AREAS COVERED: Nanosystems offer a promising approach for precise drug delivery to tumor lesions. In this review, we provide an overview of the current research progress in the development of nanosystems that modulate adenosine signaling for tumor immunotherapy. These nanosystems are designed to target adenosine-hydrolyzing proteins, increase adenosine decomposition, and antagonize adenosine receptors. EXPERT OPINION: Based on the literature review, adenosine has great potential in tumor immunotherapy, and nano-drug delivery system has great application prospects in targeted cancer therapy in the near future due to its superior characteristics.

Novel three-dimensional fibrous covalent organic frameworks constructed via silver amalgam bridging for efficient organic dye adsorption and removal.

The construction of covalent organic frameworks (COFs) with unique structures has great significance in exploring the structure-function relationship and extending their potential applications. Fibrous COFs have demonstrated superior performance in specific application scenarios owing to the distinctive three-dimensional (3D) structure. Herein, we report a facile strategy for the fabrication of 3D COF nanofiber by exploiting silver amalgam as a bridging agent to assemble one-dimensional-extended PA-COF modules into a tubular structure. Dimensions of the obtained 3D COF nanofiber were predicted by DFT calculations, and the nanofiber was endowed with the merits of favorable uniformity and high stability. Due to the enhanced exposure of conjugatable binding sites for dye retention offered by the novel 3D architecture, the PA-COF nanofiber exhibits fast adsorption (within 5 min) and superior adsorption capacity to various organic dyes, e.g., 1717 mg g-1 for methylene blue (MB) and 978.3 mg g-1 for methyl orange (MO). Moreover, the PA-COF nanofiber shows excellent reusability in dye adsorption, which makes it a potential medium for removing dye pollutants from wastewater. This work presents an effective strategy to construct COF materials with unique architecture and potential prospects in the fields of separation and wastewater treatment.

Bortezomib elevates intracellular free Fe2+ by enhancing NCOA4-mediated ferritinophagy and synergizes with RSL-3 to inhibit multiple myeloma cells.

Iron contributes to tumor initiation and progression; however, excessive intracellular free Fe2+ can be toxic to cancer cells. Our findings confirmed that multiple myeloma (MM) cells exhibited elevated intracellular iron levels and increased ferritin, a key protein for iron storage, compared with normal cells. Interestingly, Bortezomib (BTZ) was found to trigger ferritin degradation, increase free intracellular Fe2+, and promote ferroptosis in MM cells. Subsequent mechanistic investigation revealed that BTZ effectively increased NCOA4 levels by preventing proteasomal degradation in MM cells. When we knocked down NCOA4 or blocked autophagy using chloroquine, BTZ-induced ferritin degradation and the increase in intracellular free Fe2+ were significantly reduced in MM cells, confirming the role of BTZ in enhancing ferritinophagy. Furthermore, the combination of BTZ with RSL-3, a specific inhibitor of GPX4 and inducer of ferroptosis, synergistically promoted ferroptosis in MM cell lines and increased cell death in both MM cell lines and primary MM cells. The induction of ferroptosis inhibitor liproxstatin-1 successfully counteracted the synergistic effect of BTZ and RSL-3 in MM cells. Altogether, our findings reveal that BTZ elevates intracellular free Fe2+ by enhancing NCOA4-mediated ferritinophagy and synergizes with RSL-3 by increasing ferroptosisin MM cells.

Communication mediated interaction between bacteria and microalgae advances photogranulation.

Recently, photogranules composed of bacteria and microalgae for carbon-negative nitrogen removal receive extensive attention worldwide, yet which type of bacteria is helpful for rapid formation of photogranules and whether they depend on signaling communication remain elusive. Varied signaling communication was analyzed using metagenomic method among bacteria and microalgae in via of two types of experimentally verified signaling molecule from bacteria to microalgae, which include indole-3-acetic acid (IAA) and N-acyl homoserine lactones (AHLs) during the operation of photo-bioreactors. Signaling communication is helpful for the adaptability of bacteria to survive with algae. Compared with non-signaling bacteria, signaling bacteria more easily adapt to the varied conditions, evidenced by the increased abundance in the operated reactors. Signaling bacteria are easier to enter the phycosphere, and they dominate the interactions between bacteria and algae rather than non-signaling bacteria. The co-abundance groups (CAGs) with signaling bacteria possess higher abundance than that without signaling bacteria (22.27 % and 6.67 %). Importantly, signaling bacteria accessibly interact with microalgae, which possess higher degree centralities and 32.50 % of them are keystone nodes in the network, in contrast to only 18.66 % of non-signaling bacteria. Thauera carrying both IAA and AHLs synthase genes are highly enriched and positively correlated with nitrogen removal rate. Our work not only highlights the essential roles of signaling communication between microalgae and bacteria in the development of photogranules, but also enriches our understanding of microbial sociobiology.

Co-Delivery of siNRF2 and Sorafenib by a "Click" Dual Functioned Hyperbranched Nanocarrier for Synergistically Inducing Ferroptosis in Hepatocellular Carcinoma.

In the course of antitumor therapy, the complex tumor microenvironment and drug-mediated changes in cell signaling and biological processes lead to drug resistance. The effect of sorafenib is greatly limited by the specific tumor microenvironment induced by antiangiogenic therapy and ferroptosis resistance induced by the upregulation of nuclear factor erythroid-2 related factor 2 (NRF2). In this study, a pH responsive and amphiphilic hyperbranched polyglycerol, HDP, is synthesized based on a co-graft click chemistry pathway. This nano-scale carrier provides excellent drug-loading capacity, storing stability and pH responsibility, and effectively co-delivery of sorafenib and siRNA. Sorafenib and siNRF2 plays a greatly synergistic effect in inducing reactive oxygen species (ROS), iron overloading, depleting glutathione (GSH), and promoting lipid peroxidation. Importantly, verified in two different animal experiments, HDP-ss (HDP loaded with both siNRF2 and sorafenib) presents a superior anti-tumor effect, by achieving a tumor inhibition rate of ≈94%. Thus, HDP can serve as an excellent targeted delivery nanocarrier with good biocompatibility in antitumor therapy, and combined application of siNRF2 effectively improves the antitumor effect of sorafenib by overcoming NRF2-mediated ferroptosis resistance. Taken together, this study provides a novel therapeutic strategy to combat the drug resistance in antiangiogenic therapy and ferroptosis.

IRGM is a novel regulator of PD-L1 via promoting S6K1-mediated phosphorylation of YBX1 in hepatocellular carcinoma.

Immunity-related GTPase M (IRGM), an Interferon-inducible protein, functions as a pivotal immunoregulator in multiple autoimmune diseases and infection. However, the role of IRGM in hepatocellular carcinoma (HCC) development remains unveiled. Here, we found interferon-γ (IFN-γ) treatment in HCC drastically triggered the expression of IRGM, and the high level of IRGM indicated poor prognosis in HCC patients. Functionally, IRGM promoted the malignant progression of HCC. Single-cell sequencing revealed that IRGM inhibition promoted the infiltration of CD8+ cytotoxic T lymphocytes (CTLs) with significant downregulation of PD-L1 expression in HCC. Furthermore, Immunoprecipitation-Mass Spectrometry assay revealed that IRGM interacted with transcription factor YBX1, which facilitated PD-L1 transcription. Mechanistically, IRGM promoted the interaction of YBX1 and phosphokinase S6K1, increasing phosphorylation and nuclear localization of YBX1, transcription of PD-L1. Additionally, the combination of IRGM inhibition with α-PD1 demonstrated a stronger anti-tumor effect compared to the single application of α-PD1. In summary, IRGM is a novel regulator of PD-L1, which suppresses CD8+ CTLs infiltration and function in HCC, resulting in cancer progression. This study may raise a novel therapeutic strategy combined with immune checkpoint inhibitors (ICIs) against HCC.

Diallyl disulfide synergizes with melphalan to increase apoptosis and DNA damage through elevation of reactive oxygen species in multiple myeloma cells.

Diallyl disulfide (DADS), one of the main components of garlic, is well known to have anticancer effects on multiple cancers. However, its efficacy in treating multiple myeloma (MM) is yet to be determined. We explored the effects of DADS on MM cells and investigated the synergistic effects of DADS when combined with five anti-MM drugs, including melphalan, bortezomib, carfilzomib, doxorubicin, and lenalidomide. We analyzed cell viability, cell apoptosis, and DNA damage to determine the efficacy of DADS and the drug combinations. Our findings revealed that DADS induces apoptosis in MM cells through the mitochondria-dependent pathway and increases the levels of γ-H2AX, a DNA damage marker. Combination index (CI) measurements indicated that the combination of DADS with melphalan has a significant synergistic effect on MM cells. This was further confirmed by the increases in apoptotic cells and DNA damage in MM cells treated with the two drug combinations compared with those cells treated with a single drug alone. The synergy between DADS and melphalan was also observed in primary MM cells. Furthermore, mechanistic investigations showed that DADS decreases reduced glutathione (GSH) levels and increases reactive oxygen species (ROS) production in MM cells. The addition of GSH is effective in neutralizing DADS cytotoxicity and inhibiting the synergy between DADS and melphalan in MM cells. Taken together, our study highlights the effectiveness of DADS in treating MM cells and the promising therapeutic potential of combining DADS and melphalan for MM treatment.

Cross-Feeding between Filamentous Cyanobacteria and Symbiotic Bacteria Favors Rapid Photogranulation.

Photogranules are dense algal-bacterial aggregates used in aeration-free and carbon-negative wastewater treatment, wherein filamentous cyanobacteria (FC) are essential components. However, little is known about the functional role of symbiotic bacteria in photogranulation. Herein, we combined cyanobacterial isolation, reactor operation, and multiomics analysis to investigate the cyanobacterial-bacterial interaction during photogranulation. The addition of FC to the inoculated sludge achieved a 1.4-fold higher granule size than the control, and the aggregation capacity of FC-dominant photogranules was closely related to the extracellular polysaccharide (PS) concentration (R = 0.86). Importantly, we found that cross-feeding between FC and symbiotic bacteria for macromolecular PS synthesis is at the heart of photogranulation and substantially enhanced the granular stability. Chloroflexi-affiliated bacteria intertwined with FC throughout the photogranules and promoted PS biosynthesis using the partial nucleotide sugars produced by FC. Proteobacteria-affiliated bacteria were spatially close to FC, and highly expressed genes for vitamin B1 and B12 synthesis, contributing the necessary cofactors to promote FC proliferation. In addition, Bacteroidetes-affiliated bacteria degraded FC-derived carbohydrates and influenced granules development. Our metabolic characterization identified the functional role of symbiotic bacteria of FC during photogranulation and shed light on the critical cyanobacterial-bacterial interactions in photogranules from the viewpoint of cross-feeding.

Chameleon-like Anammox Bacteria for Surface Color Change after Suffering Starvation.

Bacteria are often exposed to long-term starvation during transportation and storage, during which a series of enzymes and metabolic pathways are activated to ensure survival. However, why the surface color of the bacteria changes during starvation is still not well-known. In this study, we found black anammox consortia suffering from long-term starvation contained 0.86 mmol gVSS-1 cytochrome c, which had no significant discrepancy compared with the red anammox consortia (P > 0.05), indicating cytochrome c was not the key issue for chromaticity change. Conversely, we found that under starvation conditions cysteine degradation is an important metabolic pathway for the blackening of the anammox consortia for H2S production. In particular, anammox bacteria contain large amounts of iron-rich nanoparticles, cytochrome c, and other iron-sulfur clusters that are converted to produce free iron. H2S combines with free iron in bacteria to form Fe-S compounds, which eventually exist stably as FeS2, mainly in the extracellular space. Interestingly, FeS2 could be oxidized by air aeration, which makes the consortia turn red again. The unique self-protection mechanism makes the whole consortia appear black, avoiding inhibition by high concentrations of H2S and achieving Fe storage. This study expands the understanding of the metabolites of anammox bacteria as well as the bacterial survival mechanism during starvation.

Multi-chambers of pilot-scale reactor enhanced partial nitritation performance.

Nowadays, applying anammox to treat high nitrogenous side-stream wastewater has taken a step forward. However, the partial nitritation process is sensitive to the ammonium concentration and the nitrogen loading rate, which significantly influences the nitrogen removal performance. This study investigated the performance of a novel nitritation pilot-scale reactor which was divided into four chambers. The nitrite accumulation efficiency reached more than 90 % in the rural wastewater treatment process. As the reactor was divided into four chambers, the comprehensive statistical results showed that the concentration of free ammonium in the front chambers had been effectively improved. The proportion of free ammonium concentration (>0.1 mg NH3·L-1), which could inhibit the activity of nitrite oxidizing bacteria, in first chamber (PN1) was 2 times higher than in the last chamber (PN4). Meanwhile, Nitrosomonas, responsible for ammonium oxidation to nitrite, was highly enriched in the first two chambers even though the dissolved oxygen was maintained at 1.5 ± 0.3 mg·L-1. Compare to conventional reactor, the resistance of the novel reactor to volumetric shock loading has been enhanced. Even though the ammonium loading rate fluctuated greatly, the effluent was still stable and could meet the demand following the anammox process. This study demonstrated that the reactor with multi-chambers could effectively improve the nitrite accumulation efficiency in the partial nitritation process and thus provide a new perspective on the partial nitritation process in a single reactor and further promote the anammox performance in the wastewater treatment process.

Wide Range Strain Distributions on the Electrode for Highly Sensitive Flexible Tactile Sensor with Low Hysteresis.

Flexible piezoresistive tactile sensors are widely used in wearable electronic devices because of their ability to detect mechanical stimuli. However, achieving high sensitivity and low hysteresis over a broad detection range remains a challenge with current piezoresistive tactile sensors. To address these obstacles, we designed elastomeric micropyramid arrays with different heights to redistribute the strain on the electrode. Furthermore, we mixed single-walled carbon nanotubes in the elastomeric micropyramids to compensate for the conductivity loss caused by random cracks in the gold film and increase the adhesion strength between the gold film (deposited on the pyramid surface) and the elastomer. Thus, the energy loss of the sensor during deformation and hysteresis (∼2.52%) was effectively reduced. Therefore, under the synactic effects of the percolation effect, tunnel effect, and multistage strain distribution, the as-prepared sensor exhibited a high sensitivity (1.28 × 106 kPa-1) and a broad detection range (4.51-54837.06 Pa). The sensitivity was considerably higher than those of most flexible pressure sensors with a microstructure design. As a proof of concept, the sensors were successfully applied in the fields of health monitoring and human-machine interaction.

Functionalization of Mesoporous Silica with a G-A-Mismatched dsDNA Chain for Efficient Identification and Selective Capturing of the MutY Protein.

MUTYH adenine DNA glycosylase and its homologous protein (collectively MutY) are typical DNA glycosylases with a [4Fe4S] cluster and a helix-hairpin-helix (HhH) motif in its structure. In the present work, the binding behaviors of the MutY protein to dsDNA containing different base mismatches were investigated. The type and distribution of base mismatch in the dsDNA chain were found to influence the DNA-protein binding interaction greatly. The [4Fe4S] cluster of the MutY protein is able to identify a G-A mismatch in the dsDNA chain specifically by monitoring the anomalies of charge transport in the dsDNA chain, allowing the entrance of the identified dsDNA chain into the internal cavity of the MutY protein and the strong DNA-protein binding at the HhH motif of the protein through multiple H-bonds. The dsDNA chain with a centrally located G-A mismatch is thus functionalized on mesoporous silica (MSN) via amination reaction, and the obtained dsDNA(G-A)@MSN is used as a powerful sorbent for the selective capturing of the MutY protein from complex samples. By using 0.5% NH3·H2O (m/v) as a stripping reagent, efficient isolation of the MutY protein from different cell lines and bacteria is achieved and the recovered MutY protein is demonstrated to maintain favorable DNA adenine glycosylase activity.

Potential bacterial isolation by dosing metabolites in cross-feedings.

Metabolic cross-feeding, in which species use metabolites of other members to promote their own growth, is vital for bacterial growth and survival. Thus, whether the unculturable bacteria can be isolated or purified from consortia by adding these essential metabolites remains elusive. In this study, mass spectrometry imaging vividly pictured symbionts supplied folate and gluconate to anammox bacteria to support their growth. After dosing folate and gluconate, the relative abundance and activity of anammox bacteria were substantially improved. Such enhancement is originated from the added folate and gluconate significantly eased metabolic burden of anammox bacteria as they no longer secreted the extracellular public goods to others for "resource exchange" during cross-feedings. On the other hand, the decreased supplement of extracellular "public goods" lead to the decay of symbionts with high demand for these metabolites in the consortia. This also deservedly increased the relative abundance of anammox bacteria. This study provides a new dimension to isolate specific functional bacteria based on metabolic cross-feedings.

Composite carrier enhanced bacterial adhesion and nitrogen removal in partial nitrification/anammox process.

The rapid start-up and stable operation of one-stage (Partial nitrification/anammox) PN/A process for low-ammonium wastewater are difficult to be achieved, and many carriers are designed to solve this problem. Here, a composite carrier was developed, in which sepiolite and non-woven fabrics were assembled in polypropylene spherical shells. At the start-up phase, PA reactor using the composite carriers reached a higher nitrogen removal rate of 134.50 ± 19.60 mg·N·L-1d-1, in contrast to that of 48.85 ± 19.64 mg·N·L-1d-1 in the PB reactor without sepiolite carriers. When the final influent ammonium concentration of PN/A process is 100 mg/L, the total nitrogen removal efficiency can reach 72 ± 0.03 %. High biomass immobilization ability of composite carrier was evidenced by the greater adsorption trend between sludge and sepiolite than that between sludge and non-woven fabrics, where hydrophobic interaction and Van der Waals interaction played a major role. Extracellular protein (PN) content and the ratio of PN and extracellular polysaccharide of samples in PA were significantly higher than those in PB, verifying higher biofilm formation ability on the composite carrier. The composite carrier also increased the abundance of dominant bacteria in PN/A process, especially AOB, the relative abundance of which reached 46.11 %. And it increased the abundance of essential functional genes for nitrogen conversion as their perfect acid neutralizing effects. This study is of great significance in improving the start-up speed and stable operation of this process.

Efficient Adsorption and Extraction of Glutathione S-Transferases with Glutathione-Functionalized Graphene Oxide-Polyhedral Oligomeric Silsesquioxane Composite.

Glutathione S-transferases (GSTs) are important type-II detoxification enzymes that protect DNA and proteins from damage and are often used as protein tags for the expression of fusion proteins. In the present work, octa-aminopropyl caged polyhedral oligomeric silsesquioxane (OA-POSS) was prepared via acid-catalyzed hydrolysis of 3-aminopropyltriethoxysilane and polymerized on the surface of graphene oxide (GO) through an amidation reaction. Glutathione (GSH) was then modified to GO-POSS through a Michael addition reaction to obtain a GSH-functionalized GO-POSS composite (GPG). The structure and characteristics of the as-prepared GPG composite were characterized using scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FT-IR), thermogravity analysis, and surface charge analysis. The specific binding interactions between glutathione and GST gave GPG favorable adsorption selectivity towards GST, and other proteins did not affect GST adsorption. The adsorption behavior of GST on the GPG composite conformed to the Langmuir isotherm model, and the adsorption capacity of GST was high up to 364.94 mg g-1 under optimal conditions. The GPG-based solid-phase adsorption process was applied to the extraction of GST from a crude enzyme solution of pig liver, and high-purity GST was obtained via SDS-PAGE identification.

Quantitative Evaluation of Small Intestinal Hemorrhage Using Energy Spectrum CT Iodine-Water Map.

The objective of this research is to analyze the quantitative evaluation of human small intestinal bleeding by observing and analyzing animal experiments of small intestinal hemorrhage in rabbit models for the convenience of understanding the role of energy spectrum CT iodine-water diagram in animal experimental research of quantitative evaluation of small intestinal bleeding in rabbit models. Compared with the energy spectrum of iodine-water graph of a rabbit CT model, the present study studied the quantitative evaluation of small intestinal bleeding by using a rabbit model instead of human. According to the method mentioned above and the analysis of experimental data, the role of energy spectrum CT iodine-water map and the quantitative evaluation of human small intestinal bleeding have been understood. It was found that the energy spectrum CT iodine-water map replaces humans in the rabbit model for quantitative evaluation of small intestinal bleeding in animal experiments, which is important in the present study. Besides, based upon the combination of theoretical and experimental data, the ten flow rates set on the base material iodine (water) maps of the arterial phase and the portal phase can be analyzed to detect the leakage of contrast agent. The yield was 100%. The research results showed that the animal experiment of quantitative assessment of small intestinal bleeding by replacing the human body with the rabbit model in the energy spectrum CT iodine-water diagram is critical to humans in the study of small intestinal hemorrhagic diseases. In addition, it can be used to adjust the treatment plan timely according to the amount of bleeding to prevent shock or heavy bleeding that threatens patients' lives.

Response of amino acid metabolism to decreased temperatures in anammox consortia: Strong, efficient and flexible.

Although amino acid (AA) metabolism is basis of bacterial activities, unique characteristics of its response to decreased temperatures are not fully understood. Achieving nitrogen removal rate of 130-150 mg N/ (L∙d), metabolic differences of anammox consortia between 35 °C and four decreased temperatures (15-30 °C) were revealed respectively. 0-11.4-fold abundance variation of marker metabolites evidenced change of key metabolism (metabolism of AA, lipid and energy production) at decreased temperatures. However, AA metabolism varied more obviously than others, implying stronger response and higher functional potential. Efficiently, network topology confirmed more cellular processes represented by growth metabolism and biofilm formation were influenced by AA metabolism. Flexibly, down-regulated biosynthesis of unfavorable AAs for psychrophilic enzyme differed from enhanced biosynthesis of costly AAs, which only matched partial decreased temperatures to save energy. This work elucidates advantages of AA metabolism over others, exogenous amino acids could significantly promote activity of anammox bacteria at decreased temperatures.

Cross-feeding among microalgae facilitates nitrogen recovery at low C/N.

Although co-culture of microalgae has been found as a feasible strategy to improve biomass production, their interspecies relationships are not fully understood. Here, two algae taxa, Chlorella sp. and Phormidium sp., were mono-cultured and co-cultured in three photobioreactors for 70 days with periodically harvesting to investigate how dual-species interaction influence nitrogen recovery. Results showed that the co-culture system achieved a significantly higher protein production and nitrogen removal rate than those in the individual cultures at a C/N ratio of 3:1 (p < 0.05). Genome-Centered metagenomic analysis revealed their cooperative relationship exemplified by cross-feeding. Phormidium sp. had the ability to synthesize pseudo-cobalamin, and Chlorella sp. harbored the gene for remodeling the pseudo-cobalamin to bioavailable vitamin B12. Meanwhile, Chlorella sp. could contribute the costly amino acid and cofactors for Phormidium sp. Their symbiotic interaction facilitated extracellular polymeric substances (EPS) production and nitrogen recovery. The EPS concentration in co-culture was positively related to the settling efficiency (R2 = 0.774), which plays an essential role in nitrogen recovery. This study provides new insights into microbial interactions among the photoautotrophic community and emphasizes the importance of algal interspecies interaction in algae-based wastewater treatment.