Extracellular polymeric substances and mineral interfacial reactions control the simultaneous immobilization and reduction of arsenic (As(V)).

Extracellular polymeric substances (EPS) play a crucial role in controlling the mobility and bioavailability of heavy metal(loid)s in water, soils, and sediments. The formation of EPS-mineral complex changes the reactivity of the end-member materials. However, little is known about the adsorption and redox mechanisms of arsenate (As(V)) in EPS and EPS-mineral complexes. Here we examined the reaction sites, valence state, thermodynamic parameters and distribution of As in the complexes using potentiometric titration, isothermal titration calorimetry (ITC), FTIR, XPS, and SEM-EDS. The results showed that ∼54% of As(V) was reduced to As(III) by EPS, potentially driven by an enthalpy change (ΔH) of - 24.95 kJ/mol. The EPS coating on minerals clearly affected the reactivity to As(V). The strong masking of functional sites between EPS and goethite inhibited both the adsorption and reduction of As. In contrast, the weak binding of EPS onto montmorillonite retained more reactive sites for the reaction with As. Meanwhile, montmorillonite facilitated the immobilization of As to EPS through the formation of As-organic bounds. Our findings deepen the understanding of EPS-mineral interfacial reactions in controlling the redox and mobility of As, and the knowledge is important for predicting the behavior of As in natural environments.

Construction of Ecological Security Patterns Based on Circuit Theory under the Resistance Distance Principle.

Against the background of China's advocating ecological civilisation construction, an urgent task and a major challenge are to identify key places for ecological protection and restoration and then propose optimisation strategies for future land use, especially in the Pearl River Delta (PRD), one of the regions in China that has the highest urbanisation level. In this study, we find the key places by constructing ecological security patterns and proposing optimisation strategies for future land use by analysing land-use status. We also propose a source identification method based on the resistance distance principle. Results show that forty-six sources were mainly distributed in the mountainous areas surrounding PRD but were less distributed along both sides of the Pearl River estuary. The difference in the spatial distribution of sources is remarkable. Eighty-four corridors generally had spider-like shapes. In the central plain of PRD, corridors were relatively long and narrow. Ninety pinch points were concentrated on existing rivers. Three barriers were located in the corridors between adjacent sources. Two artificial corridors were proposed to be established, which can improve the ecological network connectivity. The method for extracting sources based on the resistance distance principle is proven to be advantageous for improving the integrity of source extraction results and making ecological security patterns more reasonable.

Humic acids restrict the transformation and the stabilization of Cd by iron (hydr)oxides.

Iron (hydr)oxides and their association with organic matter significantly affect the mobility of heavy metals in natural soils and sediments. However, the behavior of cadmium (Cd) during crystalline iron (hydr)oxide formation in the presence of humic acid (HA) is still unknown. In this study, the speciation of Cd in iron (hydr)oxide-HA coprecipitates were studied by extraction, surface complexation model (SCM) calculation and characterization of the composites during the aging. The results showed that aging promoted the stabilization of ~30-50% of the added Cd ions with minerals in the binary iron (hydr)oxide systems. The reduction of Cd occurred earlier than hematite formation, indicating that the aggregation of amorphous iron (hydr)oxide led to the initial immobilization of Cd. The presence of HA restricted the crystallization of iron (hydr)oxide by the formation of tight mineral nanoparticle-HA aggregates, while there were negligible changes in the speciation of Cd and Fe during aging at high HA concentrations. Therefore, HA promoted the adsorption of Cd onto amorphous iron (hydr)oxide but limited the partition of Cd to mineral aggregates. The knowledge about the role of HA in iron (hydr)oxide transformation and Cd speciation is of great significance for the prediction of heavy metal behavior in soils and sediments.

Functional group diversity for the adsorption of lead(Pb) to bacterial cells and extracellular polymeric substances.

Bacteria and their secreted extracellular polymeric substances (EPS) are widely distributed in ecosystems and have high capacity for heavy metal immobilization. The knowledge about the molecular-level interactions with heavy metal ions is essential for predicting the behavior of heavy metals in natural and engineering systems. This comprehensive study using potentiometric titration, Fourier-transform infrared (FTIR) spectroscopy, isothermal titration calorimetry (ITC) and X-ray absorption fine structure (XAFS) was able to reveal the functional diversity and adsorption mechanisms for Pb onto bacteira and the EPS in greater detail than ever before. We identified mono-carboxylic, multi-carboxylic, phosphodiester, phosphonic and sulfhydryl sites and found the partitioning of Pb to these functional groups varied between gram-negative and gram-positive bacterial strains, the soluble and cell-bound EPS and Pb concentrations. The sulfhydryl and phosphodiester groups preferentially complexed with Pb in P. putida cells, while multifunctional carboxylic groups promoted Pb adsorption in B. subtilis cells and the protein fractions in EPS. Though the functional site diversity, the adsorption of Pb to organic ligands occurred spontaneously through a universal entropy increase and inner-sphere complexation mechanism. The functional group scale knowledge have implications for the modeling of heavy metal behavior in the environment and application of these biological resources.

Tumor-Derived Extracellular Vesicles: Their Role in Immune Cells and Immunotherapy.

Nowadays, tumor has been the serious threat to human health and life. To further explore the mechanism of tumor genesis and development is necessarily for developing the effective treatment strategy. Extracellular vesicles are the vesicles secreted by almost all types of cells, and they play an important part in intercellular communication by transporting their cargoes. Immune cells are the vital components of the human defense system, which defense against infection and tumor through cytotoxicity, immune surveillance, and clearance. However, via release tumor-derived extracellular vesicles, tumor could induce immune cells dysfunction to facilitate its proliferation and metastasis. Studies have shown that tumor-derived extracellular vesicles play dual role on immune cells by their specific cargoes. Here, we reviewed the effects of tumor-derived extracellular vesicles on immune cells in recent years and also summarized their research progress in the tumor immunotherapy and diagnosis.

Extracellular Vesicles - Advanced Nanocarriers in Cancer Therapy: Progress and Achievements.

Extracellular vesicles (EVs) are a class of cell-derived, lipid bilayer membrane composed vesicles, and some of them such as exosomes and ectosomes have been proven, playing remarkable roles in transmitting intercellular information, and being involved in each property of cell physiological activities. Nowadays, EVs are considered as potential nanocarriers which could partially resolve the problems of current chemotherapy because of their distinctive advantages. As endogenous membrane encompassed vesicles with nanosize, EVs are able to pass through the natural barriers with prolonged circulation time in vivo and have intrinsic cell targeting properties, they are less toxic, and less immunogenic. Recently, studies focusing on EV-based drug delivery system for cancer therapy have exploded dramatically. This review aims to outline the current applications of EVs as potential nanosized drug carriers in cancer therapy. Firstly, the characteristics and biofunctions of each EV subtype are described. Then the variety of therapeutic cargoes, the loading methods, and the targeting strategy of engineered EVs are emphatically introduced. Thereafter the pros and cons of EVs applied as therapeutic carriers, as well as the future prospects in this field, are discussed.

Mining reported adverse events induced by potential opioid-drug interactions.

OBJECTIVE: Opioid-based analgesia is routinely used in clinical practice for the management of pain and alleviation of suffering at the end of life. It is well-known that opioid-based medications can be highly addictive, promoting not only abuse but also life-threatening overdoses. The scope of opioid-related adverse events (AEs) beyond these well-known effects remains poorly described. This exploratory analysis investigates potential AEs from drug-drug interactions between opioid and nonopioid medications (ODIs). MATERIALS AND METHODS: In this study, we conduct an initial exploration of the association between ODIs and severe AEs using millions of AE reports available in FDA Adverse Event Reporting System (FAERS). The odds ratio (OR)-based analysis and visualization are proposed for single drugs and pairwise ODIs to identify associations between AEs and ODIs of interest. Moreover, the multilabel (multi-AE) learning models are employed to evaluate the feasibility of AE prediction of polypharmacy. RESULTS: The top 12 most prescribed opioids in the FAERS are identified. The OR-based analysis identifies a diverse set of AEs associated with individual opioids. Moreover, the results indicate many ODIs can increase the risk of severe AEs dramatically. The area under the curve values of multilabel learning models of ODIs for oxycodone varied between 0.81 and 0.88 for 5 severe AEs. CONCLUSIONS: The proposed data analysis and visualization are useful for mining FAERS data to identify novel polypharmacy associated AEs, as shown for ODIs. This approach was successful in recapitulating known drug interactions and also identified new opioid-specific AEs that could impact prescribing practices.

Improvement of l-Valine Production by Atmospheric and Room Temperature Plasma Mutagenesis and High-Throughput Screening in Corynebacterium glutamicum.

As one of the branched-chain amino acids, l-valine is an essential nutrient for most mammalian species. In this study, the l-valine producer Corynebacterium glutamicum ΔppcΔaceEΔalatΔpqo was first constructed. Additionally, an improved biosensor based on the Lrp-type transcriptional regulator and temperature-sensitive replication was built. Then, the C. glutamicum strain was mutagenized by atmospheric and room temperature plasma. A sequential three-step procedure was carried out to screen l-valine-producing strains, including the fluorescence-activated cell sorting (FACS), 96-well plate screening, and flask fermentation. The final mutant HL2-7 obtained by screening produced 3.20 g/L of l-valine, which was 21.47% higher than the titer produced by the starting strain. This study demonstrates that the l-valine-producing mutants can be successfully isolated based on the Lrp sensor system in combination with FACS screening after random mutagenesis.

Cultivation and Medicinal Value of the Red Belt Conk Mushroom Fomitopsis pinicola (Agaricomycetes).

This study examined biological characteristics, liquid fermentation, and cultivation of Fomitopsis pinicola. A single-factor test concluded that the optimal carbon and nitrogen sources for mycelial growth were soluble starch and yeast paste; the optimal culture temperature was 31°C, and the optimal pH was 6.0. The orthogonal experiment indicated that the optimal formula for mycelial culture was 25 g soluble starch, 2 g yeast extract, 1 g KH2PO4, and 1.5 g MgSO4 added to 1 L water. The optimal conditions for liquid fermentation culture consisted of the following: a loading volume 90 mL, inoculation volume 30 mL, and rotation speed 160 rpm. The optimal substrate formula for domestic culture was 20% corn cob, 30% sawdust, 20% wheat bran, 25% cotton seed shell, 3% corn meal, 1% gypsum, and 1% lime, which produced the highest yield of fruiting bodies. The results provided basic data for deep liquid fermentation culture and recommendations for the further development and utilization of F. pinicola.

Dynamic change in spring habitat use by the brown eared pheasant (Crossptilon mantchuricum) in the Huanglong mountains, Yanan City, Shaanxi Province, China.

Characterization of foraging-site preferences of threatened and endangered species is a key component of effective habitat conservation. We studied foraging-site selection by the brown eared pheasant (Crossoptilon mantchuricum) in the Huanglongshan Nature Reserve, Yanan City, Shaanxi Province, China, from early February to end of May 2011. We identified feeding sites by locating tracks and scratches characteristic of the birds, and compared habitat characteristics at these sites to those at randomly selected sites across the study area. During the pre-breeding season, the birds tended to be found in the areas characterized by gullies within mixed forests with intermediate sun exposure on gentle slopes (< 10°), and close to water and footpaths. The sites utilized by the birds also featured greater tree diameter, lower shrub density, lower grass cover, and lower altitude than random sites. During the breeding season, the birds tended to be found in the areas of slightly higher altitude, more shrubs, moderately steep slopes (10°-20°), and farther from water and paths. These patterns were consistent with seasonal changes in vegetation and food-resource availability in the study area. Management of brown eared pheasants' populations for conservation must account for these seasonal shifts in habitat requirements.