Copper selenide nanosheets with photothermal therapy-related properties and multienzyme activity for highly effective eradication of drug resistance.

Bacterial infections are among the most significant causes of death in humans. Chronic misuse or uncontrolled use of antibiotics promotes the emergence of multidrug-resistant superbugs that threaten public health through the food chain and cause environmental pollution. Based on the above considerations, copper selenide nanosheets (CuSe NSs) with photothermal therapy (PTT)- and photodynamic therapy (PDT)-related properties have been fabricated. These CuSe NSs possess enhanced PDT-related properties and can convert O2 into highly toxic reactive oxygen species (ROS), which can cause significant oxidative stress and damage to bacteria. In addition, CuSe NSs can efficiently consume glutathione (GSH) at bacterial infection sites, thus further enhancing their sterilization efficacy. In vitro antibacterial experiments with near-infrared (NIR) irradiation have shown that CuSe NSs have excellent photothermal bactericidal properties. These experiments also showed that CuSe NSs exerted excellent bactericidal effects on wounds infected with methicillin-resistant Staphylococcus aureus (MRSA) and significantly promoted the healing of infected wounds. Because of their superior biological safety, CuSe NSs are novel copper-based antimicrobial agents that are expected to enter clinical trials, serving as a modern approach to the major problem of treating bacterially infected wounds.

A new strategy for obtaining highly concentrated phosphorus recovery solution in biofilm phosphorus recovery process.

Recovery of phosphorus (P) from wastewater is of great significance for alleviating the shortage of P resources. At present, the P recovery process is faced with the problem of excessive organic carbon consumption when obtaining a P-concentrated recovery solution. This study proposed a new strategy to obtain a more highly concentrated P recovery solution with minimal carbon consumption by strengthening the P storage capacity of the biofilm. A biofilm sequencing batch reactor (BSBR) process was modified to treat synthetic wastewater. The effect of the dissolved oxygen (DO) concentration on the P storage capacity of the biofilm was investigated at DO concentrations of DO 3.5 mg/L (PL) and DO 6.5 mg/L (PH). The results showed a maximum P storage of 101.2 and 149.6 mg-P/g-mixed liquid suspended solids under the two conditions. Strengthening the P storage capacity of the biofilm resulted in a net increase in the P recovery rate, which was as high as 66.96% in a harvesting cycle, and total soluble P>220 mg/L in the P recovery solution was successfully achieved. Meanwhile, the carbon cost of P recovery in the BSBR was reduced to 41.57 g-chemical oxygen demand/g-P, and the carbon utilization efficiency was enhanced. To highlight the new strategy, the P recovery performance of the BSBR was given and the relationship between P content and anaerobic P release was discussed. In addition, the changes in the microbial communities under PL and PH conditions were analyzed.

Enhanced phosphorus storage in suspended biofilm by increasing dissolved oxygen.

The phosphorus recovery efficiency in PAOs-biofilm system is so far limited to stimulating phosphorus release by adding concentrated organic carbon solution during the anaerobic stage. In present study, a PAOs-biofilm sequence batch reactor (BSBR) were operated to investigate whether increase of the phosphorus storage content via DO control can stimulate the release in the biofilm. During the operation of BSBR for 160 days, the phosphorus content in biofilm (Pbiofilm) was doubled via increasing dissolved oxygen (DO) from 4 to 6 mg/L. With the COD of 200 mg/L in the anaerobic phase, the phosphorus release was enhaced, resulting in an significant increase of phosphorus concentration from 94.85 to 179.5 mg/L in recirculated solution. Batch tests further clarified explicitly the increase of Pbiofilm stimulated a phosphorus release rate but this must be balanced since high Pbiofilm reduced the phosphorus removal capacity of the biofilm. With analysis of P31-NMR, Ortho-P and Poly-P were the main phosphorus species stored in biofilm. The microbial cell played a more important role than EPS in phosphorus storage. The dominant phylum in the master reactor was Proteobacteria with an abundance of 64.4%, in which the Rhodocyclaceae was the dominant PAOs with an abundance of 10.1%. The outcome of this study elucidated that increase of phosphorus storage via DO control which facilitated more efficient phosphorus release with much lower organic carbon source consumption during the enrichment of phosphorus. Meanwhile, we provided a new perspective for the recovery of phosphorus in future wastewater treatment plants.

[Microbial Population Dynamics During Domestication and Cultivation of Biofilm to Remove and Enrich Phosphate].

The purpose of this study was to develop a method to remove and recover high concentration phosphate solutions from wastewater. An experiment was carried out to cultivate and enrich phosphorus accumulating organisms (PAOs) in the biofilm with nylon as the biological carrier using artificial water distribution. Microflora morphology, species diversity, and the genetic relationship of biofilm during the process of biofilm domestication were studied by scanning electron microscopy (SEM) and MiSeq high-throughput sequencing. In addition, the feasibility of recycling a high concentration of phosphate in the conventional biofilm within a short time was validated. The membrane was hung in the biological carrier when the reactor was operated for 10 d. After the hanging of the film succeeded, the effluent COD was below 50 mg·L-1, the effluent phosphorus was close to zero, and the removal efficiency of phosphorus reached to above 95%. The operation was stable at this level for 40 d. The results from the SEM indicated that the microbial morphology in the biofilm was uniform with full oval-shaped spheres with a clear profile. MiSeq high-throughput sequencing indicated that the dominant phylum in the reactor included Proteobacteria, Chloroflexi, Bacteroidetes, Actinobacteria, Ignavibacteriae, and Nitrospirae. Proteobacteria, as the dominant genera, increased from 47% to 58%. Rhodocyclaceae, as the dominant phosphorus accumulating bacteria, increased from 17.9% to 28.9%. During the recovery period, the concentration of the phosphorus solution increased from 40mg·L-1 to 82 mg·L-1 by increasing the influent phosphate concentration and the COD concentration in the anaerobic phase, meeting the requirement of phosphorus recovery with the struvite method.

Inhibitory effect of mitragynine, an analgesic alkaloid from Thai herbal medicine, on neurogenic contraction of the vas deferens.

The effect of an indole-alkaloid mitragynine isolated from the Thai medicinal herb kratom (Mitragyna speciosa) on neurogenic contraction of smooth muscle was studied in guinea-pig vas deferens. Mitragynine inhibited the contraction of the vas deferens produced by electrical transmural stimulation. On the other hand, mitragynine failed to affect the responses to norepinephrine and ATP. Mitragynine did not reduce KCl-induced contraction in the presence of tetrodotoxin, prazosin and alpha,beta-methylene ATP. Mitragynine inhibited nicotine- or tyramine-induced contraction. By using the patch-clamp technique, mitragynine was found to block T- and L-type Ca2+ channel currents in N1E-115 neuroblastoma cells. In the Ca2+ measurement by a fluorescent dye method, mitragynine reduced KCl-induced Ca2+ influx in neuroblastoma cells. The present results suggest that mitragynine inhibits the vas deferens contraction elicited by nerve stimulation, probably through its blockade of neuronal Ca2+ channels.