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Seleniferous red soils cover a large area in the southern part of China. These agricultural soils are enriched in selenium (Se), heavy metals, and rare earth elements and have been cultivated for more than 1000 years for rice production without any consideration of the effects of selenium, heavy metals, and rare earth element bioaccumulation in the food plants produced. To address this knowledge gap, this study focuses on the investigation of Se, heavy metals, and rare earth elements within soils and plants in the region. The rice (Oryza spp.) plants studied were grown in the Gutian (GT), Gechuan (GC), and Pengkou (PK) villages in Lianchen (LC) County, Fujian Province. The surface soils and harvested rice tissues were collected to determine the Se, Cd, Zn, Pb, La, Ce, and Nd concentrations in the soils and plant tissues. Different rice cultivars possessed various potentials for elemental accumulation. Generally, rice plant tissues accumulated certain amounts of these elements; however, the elemental concentrations found in rice grain were within the acceptable ranges stipulated by the National Security Standard of Food. The Hongbaoshi (HBS) Indica red rice produced in the PK village accumulated more selenium, heavy metals, and rare earth elements than those in the plant tissues of the Xinyinzhan (XYZ) and Wushansimiao (WSSM) rice cultivars because HBS had more root hairs and finer root distribution. Thus, in the interest of food safety, increased attention needs to be given to the careful selection of the optimum crop species planted in these types of seleniferous red soils.

Soil microbes are the key to revealing the mechanisms driving variation in soil biogeochemical processes. In recent decades, forests in Southeast China have been widely transformed into tea plantations due to the drivers of economic benefits. However, the changes in the soil microbial community and their potential function during the transition from a typical forest ecosystem to tea plantations remain poorly understood. This study investigated the soil microbial community in tea plantation soils with different planting ages, i.e., 6, 12, 23 and 35 years, and in an adjacent woodland control. We discovered that tea planting significantly increased soil bacterial richness (ACE and Chao1) and decreased fungal richness, the diversity of bacteria (Simpson and Shannon) show a trend of initially decreasing and then increasing while there was no significant effect on fungal diversity. After tea planting, the relative abundances of Actinobacteria and Proteobacteria increased by 180.9%–386.6% and 62.3%–97.5%, respectively; the relative abundances of Acidobacteria decreased by 11.4%–66.8%. However, the fungal phyla were not significantly different among different aged tea plantations and woodlands. FAPROTAX and FUNGuild revealed that the transition of natural woodland to tea plantations significantly increased the relative abundances of aerobic_chemoheterotrophy (14.66%–22.69%), chemoheterotrophy (34.36%–37.04%), ureolysis (0.68%–1.35%) and pathogenic fungi (26.17%–37.02%). db-RDA proved that the bacterial community structure was more strongly related to soil pH and available nitrogen (AN), while the main determinants of the fungal community composition were soil pH and soil organic matter (SOM). These findings indicate that tea planting has a strong effect on the soil microbial community and potential function. The change in soil pH during tea planting was the most important factor affecting the soil microbial community, while soil bacteria were more sensitive to tea planting than fungi.

A trend in large yellow croaker (Larimichthys crocea) aquaculture is to establish new production sites that are suitable for extreme weather conditions. However, continuous and strong currents can harm fish welfare. To determine the location of the net cage, it is necessary to assess the swimming ability of large yellow croaker. Currently, our research on large yellow croakers is focusing on behavior analysis. This article investigates the effect of swimming large yellow croakers on metabolites in the body by examining the preferred speed of the group and the endurance swimming ability of single-tailed fish. We evaluated the factors that influence the large yellow croaker’s swimming fatigue by quantifying the content of metabolites and constructed the endurance swimming model using those results. Various results showed large yellow croaker populations tend to grow in low-velocity environments, and this matches their traditional habitat. The samples were taken at different swimming times at a flow rate of 0.35 m/s. According to the results of the metabolite content determination, blood glucose levels is closely related to swimming ability in large yellow croakers. The content of liver glycogen, which regulates blood glucose concentration, decreases in a certain linear relationship. The endurance swimming model of large yellow croaker was constructed according to the changes of liver glycogen content. The goals of this article are to provide a deeper understanding of the physiological characteristics of large yellow croaker swimming, and to provide a reference for choosing fishing and cage sites for large yellow croaker.

Spent mushroom substrate (SMS) is the residue after mushroom production. The aims of this work were to analyze the effects of continuous application of SMS for nearly 10 years on soil organic carbon (SOC), soil humus composition, microbial biomass and functional diversity in paddy fields and to provide a theoretical basis for scientific application of SMS. A continuous application of SMS from Agaricus bisporus experiment was established in paddy field of southeastern China in 2007. Soils were collected from 6 treatments in 2016. The results showed that application of SMS could significantly increase the contents of SOC, soil total alkali-soluble humic carbon (HEC), humic acid carbon (HAC), especially the treatment of with high quantity of SMS, but not significantly increase the content of fulvic acid carbon (FAC). The microbial biomass carbon and nitrogen contents of MR3 (the amounts of SMS were 9574.5 kg hm−2, converted to pure nitrogen were 180 kg hm−2) were the largest, it illustrated that the amount of SMS was not the more the better. The average well color development (AWCD), the Shannon index, Simpson index and McIntosh index of MR3 treatment were the highest. Microorganisms of MR3 treatment could make better use of carbon sources. Carboxylic acids, carbohydrates and polymers were the main carbon source types. Sufficient but not excessive application of SMS was beneficial to the carbon source utilization of fast-growing microorganisms and was considered to be a good way to improve the productivity of paddy soil.

A viscous tertiary amine and triol, triethanolamine, is engaged in this work as a structure-shaping agent to prepare the high-quality ZnO nanosheets under mild conditions, i.e., at nearly neutral pH and low temperature. The X-Ray diffraction and transmission electron microscopic results validated that the obtained ZnO nanosheets show the perfect hexagonal nanostructures, with an average edge length of 46.6 ± 8.5 nm. The triethanolamine molecule is deemed to act as the hydroxide anion generator as well as the surface modification agent, as evidenced by the FT-IR spectrum. The mechanism for the formation of ZnO nanosheets has been discussed. The simple strategy allows the efficient syntheses of fluorescent ZnO with the strong emission around 560 nm, which was attributed to the defect emission of the ZnO nanostructures. The predominant fluorescent properties have been successfully used in the field of cellular imaging, suggesting their promising biomedical applications.

Combinations of cancer therapy modalities are attracting attention to improve the outcome of treatment, since single modality has not always been sufficiently effective. The aim of this study was to investigate a new strategy of combined application of ZnO nanorods with anticancer drug daunorubicin (DNR) in photodynamic therapy (PDT). Using a simple one-step solid state reaction in air at room temperature, we were able to fabricate ZnO nanorods as the drug carrier of DNR in drug delivery system. The combination of ZnO nanorods with DNR induced the remarkable improvement in the anti-tumor activity, which has been demonstrated by the flow cytometry, MTT assay and nuclear DAPI staining. Furthermore, the possible signaling pathway was explored by immunocytochemistry. It was noted that the notable photodynamic activity of the non-cytotoxic ZnO nanorods could considerably increase cancer cell injury mediated by reactive oxygen species (ROS). For instance, in human hepatocarcinoma cells (SMMC-7721 cells), our observations demonstrated that ZnO nanorods could obviously increase the intracellular concentration of DNR and enhance its potential anti-tumor efficiency, indicating that ZnO nanorods could act as an efficient drug delivery carrier importing DNR into target cancer cells. Furthermore, photodynamic ZnO nanorods loaded chemotherapeutic agent could induce distinguished improvement in anti-tumor activity with UV illumination. These findings revealed that such modality combinations represent a promising approach in cancer therapy.

The multidrug resistance (MDR) in cancer is a major chemotherapy obstacle, rendering many currently available chemotherapeutic drugs ineffective. The aim of this study was to explore the new strategy to early diagnose the MDR by electrochemical sensor based on carbon nanotubes-drug supramolecular interaction. The carbon nanotubes modified glassy carbon electrodes (CNTs/GCE) were directly immersed into the cells suspension of the sensitive leukemia cells K562 and/or its MDR cells K562/A02 to detect the response of the electrochemical probe of daunorubicin (DNR) residues after incubated with cells for 1h. The fresh evidence from the electrochemical studies based on CNTs/GCE demonstrated that the homogeneous, label-free strategy could directly measure the function of cell membrane transporters in MDR cancer cells, identify the cell phenotype (sensitive or MDR). When the different ratios of the sensitive leukemia cells K562 and its MDR ones K562/A02 were applied as a model of MDR levels to simulate the MDR occurrence in cancer, the cathodic peak current showed good linear response to the fraction of MDR with a correlation coefficient of 0.995. Therefore, the MDR fraction can be easily predicted based on the calibration curve of the cathodic peak current versus the fraction of MDR. These results indicated that the sensing strategy could provide a powerful tool for assessment of MDR in cancer. The new electrochemical sensor based on carbon nanotubes-drug supramolecular nanocomposites could represent promising approach in the rapid diagnosis of MDR in cancer.

Recently, ZnO nanostructures with various morphologies have been synthesized with different structure directing agents. Among these works, little reports have been focused on the syntheses of the ZnO nanostructures at nearly neutral pH and relatively low temperature. This work explores a novel structure-directing agent, tris(hydroxymethyl)aminomethane (tris), for one-pot synthesis of hexagonal ZnO nanosheets at nearly neutral pH (i.e., 7.3) and low temperature (i.e., 80 degrees C). From the XRD and TEM results, the obtained ZnO nanosheets possess the perfect single crystalline structures. The tris molecule acts not only as the hydroxide anion generator, but also as the surface modification agent, as evidenced by the FT-IR spectrum. The yield of the products can be up to about 1.0 g per pot, indicating the industrial prospects for its large-scale and low-cost synthesis. The mechanism of nucleation and growth of the ZnO nanosheets has been proposed. The obtained ZnO nanosheets own the sharp strong fluorescence at 590 nm, which can be attributed to the defects on the surface of the ZnO nanostructures. In virtue of the fluorescent properties, the ZnO nanosheets have been successfully used for cell imaging, suggesting their promising clinic and biomedical applications.

In this work we discovered the potential-triggered adsorption of the thioglycerol stabilized CdSe nanoparticles on the glassy carbon electrode (GCE), which induced the electrochemiluminescence (ECL) of the nanoparticles coreacted with triethylamine. The increasing ECL emission was controlled by the applied potential of the electric field, with an optimized potential of +1.0 V. The adsorption event of the nanoparticles on the GCE was quantitatively identified by the stripping voltammetric analysis of Cd 2+ ions, etc. The ECL emission was also found to be notably enhanced after the removal of the interference from the dissolved oxygen. These results would be helpful to make the full understanding of the ECL processes by the CdSe nanoparticles–tertiary amines system and promote the design of the high-sensitive bioelectronic sensors.

Nanomaterials have widely been used in the field of biological and biomedicine, such as tissue imaging, diagnosis and cancer therapy. In this study, we explored the cytotoxicity and photodynamic effect of different-sized ZnO nanoparticles to target cells. Our observations demonstrated that ZnO nanoparticles exerted dose-dependent and time-dependent cytotoxicity for cancer cells like hepatocellular carcinoma SMMC-7721 cells in vitro. Meanwhile, it was observed that UV irradiation could enhance the suppression ability of ZnO nanoparticles on cancer cells proliferation, and these effects were in the size-dependent manner. Furthermore, when ZnO nanoparticles combined with daunorubicin, the related cytotoxicity of anticancer agents on cancer cells was evidently enhanced, suggesting that ZnO nanoparticles could play an important role in drug delivery. This may offer the possibility of the great potential and promising applications of the ZnO nanoparticles in clinical and biomedical areas like photodynamic cancer therapy and others.

This work designs a new strategy for the direct synthesis of different zinc oxide (ZnO) nanostructures at low temperatures. Micelles of dodecylamine (DDA) assembled in an ethanol-water system have been explored as a template to direct the growth of the ZnO nanostructures. The key species for the formation of the ZnO nanostructures, OH(-), can be provided by the water-induced protonation of DDA. The pH of the reaction micro-environment can be regulated by changing the input amount of water and DDA. By controlling the reaction temperature and pH, various ZnO nanostructures, i.e. quantum dots with green or yellow-green emissions, have been prepared. The relationship of the optical properties and the synthetic conditions has been further discussed. This strategy realizes the convenient preparation of ZnO QDs, indicating the potential prospects in the nanotechnology field for their low-cost synthesis. Meanwhile, the cellular toxicity study of ZnO nanoparticles toward cancer cells, including leukemia K562 and K562/A02 cells as well as HepG2 cells, indicates a selective cytotoxic effect of ZnO QDs against a broad range of human cancer cell lines.

The emergence of the multidrug resistance (MDR) phenomenon in tumor has rendered many currently available chemotherapeutic drugs ineffective. Although many strategies have been explored to overcome MDR, the results have been disappointing to the obstacle. The aim of this study was to investigate whether the new strategy of combining drug-loaded nanoparticles (Nps) and ultrasound (US) would show useful effects on the reversal of MDR in tumor. The MDR leukemia K562/A02 cells were treated with the daunorubicin (DNR)-loaded TiO2 Nps drug carrier and US exposure. We observed good biocompatibility of the therapeutic approach, and the fresh evidence from the electrochemical studies, MTT assays, and caspase-3 immunocytochemistry demonstrated that the strategy could significantly increase the uptake of DNR by drug-resistant leukemia cells, and enhance the sensitivity of the MDR cells to the chemotherapeutic agents after released in the cells. The resisting fold became obviously lower and the apoptosis was induced in the cells as well. It was therefore concluded that the strategy could have good reversal ability of MDR in tumor. These findings reveal that the reversal of MDR in tumor by US mediated drug-loaded Nps crossing cell membranes could represent promising approach in cancer therapy.

Strong alkaline microcavities were constructed through the water-induced protonation of dodecylamine for the synthesis of fluorescence-tunable ZnO QDs in neutral bulk reaction solution.

Through the anaerobic chromatography on the columns of DEAE 52, Q-Sepharose and Sephacryl S-200, a nitrogenase MoFe protein (ΔnifZ Av1) was obtained from a nifZ deleted mutant of Azotobacter vinelandii (stain DJ194). The results of Western blotting after anoxic native electrophoresis and SDS-PAGE showed that ΔnifZ Av1 was similar to wild type MoFe protein (OP Av1) at the electrophoretic mobility, molecular weight and subunit composition. Furthermore, ΔnifZ Av1 was also similar to OP Av1 at the molybdenum content, EPR signal (g ≈ 4.3, 3.65 and 2.01), and the molar extinction coefficient (Δe) of circular dichroism (CD) at 660 nm region. All of these indicated that, besides having the same α2β2 composition as OP Av1, the ΔnifZ Av1 also contained equal amount of reductive FeMoco in the spin state of S=3/2 to OP Av1. However, the iron content and substrate (C2H2, H+ and N2)-reduction activity of ΔnifZ Av1 were 74% and 46%–50% of those of OP Av1, respectively. Furthermore, the Δe at around 450 nm, which reflects P-cluster in Av1, was obviously lower than that of OP Av1. It suggested that the difference between ΔnifZ Av1 and OP Av1 resulted from P-cluster rather than FeMoco, and from the half number of P-cluster in ΔnifZ Av1, but the composition or redox state of P-cluster in ΔnifZ Av1 were not changed. Thus it could propose that ΔnifZ Av1 is composed of two different αβ subunit pairs. One is a FeMoco- and P-cluster-containing pair, and the other is a P-cluster-deficient but FeMoco-containing pair. Since the deletion of nifZ gene leads to the deficiency of only one of two P-clusters in a α2β2 tetramer, the assembly of P-cluster may not simply depend on one gene product, and so a possible mechanism of NifZ is supposed here.