Effects of antibiotics stress on root development, seedling growth, antioxidant status and abscisic acid level in wheat (Triticum aestivum L.).

The veterinary antibiotics contamination in agroecosystems is a substantial problem globally. However, little is known about their toxicity to crops, especially in wheat. This study evaluated the phytotoxic effects of the two most representative antibiotics, namely oxytetracycline (OTC) and enrofloxacin (ENR), on seed germination, seedling growth, root elongation and antioxidant status in wheat, and investigated the response of abscisic acid (ABA) to antibiotic stress and its underlying mechanism. The results showed that OTC and ENR under the experimental concentrations (5, 10, 20, 40 and 80 mg·L-1) had no influence on seed germination of wheat. The reduced root length, fresh weight and surface area were observed when the concentrations of OTC and ENR were higher than 10 mg·L-1 and 5 mg·L-1, respectively. High concentrations (＞40 mg·L-1) of antibiotics dramatically decreased the root length, fresh weight, root numbers and surface area as well as the number of stele cells and stele area. The activity of catalase (CAT), superoxide dismutase (SOD) and peroxidase (POD), and malondialdehyde (MDA) content in shoots and roots were increased with the increasing OTC and ENR concentrations. High concentrations (＞40 mg·L-1) of antibiotics improved ABA content and enhanced the transcription levels of genes related to ABA biosynthesis (TaNCED1 and TaNCED2) and metabolism (TaABA8'OH1-A and TaABA8'OH2-A) in shoots and roots of wheat seedlings. Wheat seedlings had relatively strong sensitivity to low concentration (5 mg·L-1) of ENR. These results suggest that OTC and ENR modulate root development and seedling growth by regulating ABA level and antioxidant defense system in wheat.

Effects of different fertilization treatments on soil microbial functional diversity of dry tableland wheat field in south Shanxi Province.

Understanding the effects of different fertilization treatments on microbial functional diversity in loess tableland wheat soil in south Shanxi Province can provide the theoretical basis from the perspective of microbial functional diversity for chemical fertilizer reduction, wheat yield increase, and soil fertility improvement in dryland soil. We conducted a long-term field experiment with seven fertilization treatments in winter wheat cultivation area of loess tableland in south Shanxi Province, including straw charcoal fertilizer (SF), bacterial fertilizer (BF), organic fertilizer (OF), humic acid fertilizer (HF), monitoring fertilizer (MF), farmer fertilizer (FF) and no fertilizer (CK). We employed Biolog-ECO microplate technique to investigate the differences of carbon source utilization capacity and functional diversity of soil microorganisms. The results showed that all the fertilization treatments could improve the metabolic activity and functional diversity of soil microbial community. Carbon source utilization was the most efficient in SF, with the overall soil microbial utilization ability of the 31 carbon sources and the utilization ability of different guilds of carbon sources being improved. Functional diversity, richness, and dominance based on microbial carbon sources utilization were significantly higher in SF treatment than that under other five treatments, and the evenness was higher than BF. Results of principal component analysis (PCA) and biclustering heatmap analysis showed that different fertilization treatments had significant effects on the metabolic function of microbial community. SF treatment could promote the functional diversity of soil microbial community, especially for the utilization of carbohydrates, carboxylic acids and amino acids. In conclusion, straw charcoal fertilizer had positive effects on soil microbial activity in wheat soil of loess tableland in south Shanxi Province.

Preparation of triangular silver nanoparticles and their biological effects in the treatment of ovarian cancer.

BACKGROUND: In recent years, silver nanoparticles (AgNPs) have gradually been widely used, especially in the field of anticancer medicine. Ovarian cancer (OC) is the gynaecological malignancy with the highest mortality rate, and the current treatment is still based on surgery, chemotherapy and postoperative targeted therapy. Therefore, the development of safe and effective nanoparticles for targeted therapy of OC is very important. This study aimed to prepare a new type of triangular silver nanoparticles (tAgNPs) and evaluate the anticancer properties for OC in vitro and in vivo. METHODS: The tAgNPs were chemically synthesized and characterized using scanning electron microscopy (SEM), ultraviolet (UV) spectrophotometry and other techniques. By performing cell-based tests, such as cell counting kit-8 (CCK-8), plate colony formation, cell apoptosis, reactive oxygen species (ROS), and western blot (WB) assays, the inhibitory effects and related mechanisms of tAgNPs on OC cells were analysed.The anticancer effect of tAgNPs in vivo was verified by a SKOV3 tumor-bearing mouse model. RESULTS: Five types of tAgNPs with different colours were successfully synthesized, with a particle size of 25-50 nm and a good dispersion. The results of in vitro experiments showed that tAgNPs treatment reduced the viability and proliferation of SKOV3 cells, arrested the cell cycle in G0/G1 phase, inhibited the expression levels of proliferation-related factors and cyclins, and promoted cell apoptosis by producing ROS and increasing caspase-3 activity. Consistent with the results of in vitro experiments, in vivo animal experiments also showed that tAgNPs significantly inhibited the proliferation of ovarian cancer. More importantly, no obvious toxic and side effects were observed. CONCLUSIONS: In this study, a novel triangular AgNPs was successfully prepared. tAgNPs are very stable, significantly inhibit the proliferation of OC cells and tumour growth in tumour-bearing mice, providing a promising nanotargeted therapy for OC.

Metal (Cd, Cr, Ni, Pb) removal from environmentally relevant waters using polyvinylpyrrolidone-coated magnetite nanoparticles.

Water pollution is a major global challenge given the increasing growth in industry and human population, and certain metals can be highly toxic and contribute to this significantly. In this study, polyvinylpyrrolidone-coated magnetic nanoparticles (PVP-Fe3O4 NPs) were used to remove metals (Cd, Cr, Ni, and Pb) from synthetic soft water and sea water in the presence and absence of fulvic acid. Nanoparticle (NP) suspensions were added to water media at a range of metal concentrations (0.1-100 mg L-1). Removal at different time points (1.5, 3, 6, 12, 24 hours) was also evaluated. Results showed that 167 mg L-1 PVP-Fe3O4 NPs could remove nearly 100% of four metals at 0.1 mg L-1 and more than 80% at 1 mg L-1. The removal decreased as the initial metal concentration increased, although essentially 100% of the Pb was removed under all conditions. The kinetic adsorption fitted well to the pseudo-second-order model and in general, the majority of metal adsorption occurred within the first 1.5 hours. These NPs are a reliable method to remove metals under a wide range of environmentally relevant conditions. Our previous research showed the NPs effectively removed oil from waters, so these NPs offer the possibility of combined in situ remediation of oil and metals.

Ecotoxicological effects of copper and selenium combined pollution on soil enzyme activities in planted and unplanted soils.

The present study explored the joint effects of Cu and Se pollution mechanisms on soil enzymes to provide references for the phytoremediation of contaminated areas and agricultural environmental protection. Pot experiments and laboratory analyses were carried out to study the individual and combined influences of Cu and Se on soil enzyme activities. The activities of four soil enzymes (urease, catalase, alkaline phosphatase, and nitrate reductase) were chosen. All soil enzyme activities tested were inhibited by Cu and Se pollution, either individually or combined, in varying degrees, following the order nitrate reductase>urease>catalase>alkaline phosphatase. Growing plants stimulated soil enzyme activity in a similar trend compared with treatments without plants. The joint effects of Cu and Se on catalase activity showed synergism at low concentrations and antagonism at high concentrations, whereas the opposite was observed for urease activity. However, nitrate reductase activity showed synergism both with and without plant treatments. The half maximal effective concentration (EC50) of exchangeable fractions had a similar trend with the EC50 of total content and was lower than that of total content. The EC50 values of nitrate reductase and urease activities were significantly lower for both Se and Cu (p<0.05), which indicated that they were more sensitive than the other two enzymes.

[Differences of selenium uptake pattern of pakchoi and the possible mechanism when amended with selenate and selenite].

In order to produce selenium-enriched crops and provide a theoretical basis of phytoremediation to selenium contaminated soil, pot experiment and lab analysis were carried out to examine the differences of selenium uptake pattern and bioavailability to pakchoi (Brassica chinensis L.) when amended with selenate and selenite. Meanwhile, dynamic changes of soil available Se was analyzed to explore the reason. The results showed that no significant differences in pakchoi shoot biomass between selenate and selenite treatment were observed. The Se concentration in pakchoi decreased rapidly across time in the selenate treatments, while increased with the growing period in the selenite treatments. For the selenate treatments, the pakchoi shoot Se concentration was significantly higher than that in roots, but the opposite results were found in the selenite treatments. In the whole growth period of pakchoi, Se concentration in selenate treatment was 2-60 times higher of that in selenite treatments. The content of available Se in soil slightly decreased with the growth of pakchoi in the selenite treatments, but it decreased rapidly in the selenate treatments. The significant correlations between soil available Se and Se concentration in shoots and roots of pakchoi was found in selenate treatments, the correlation coefficients were 0.901 and 0.864, respectively. On the contrast, no significant correlation was observed between soil available Se and Se concentration of roots and shoots in selenite treatments. The results indicated that the differences between the Se uptake pattern of selenate and selenite on pakchoi were the comprehensive function of the ability of soil providing Se and crop uptake ability.