Microplastics shape microbial interactions and affect the dissemination of antibiotic resistance genes in different full-scale wastewater treatment plants.

Wastewater treatment plants (WWTPs) pose a potential threat to the environment because of the accumulation of antibiotic resistance genes (ARGs) and microplastics (MPs). However, the interactions between ARGs and MPs, which have both indirect and direct effects on ARG dissemination in WWTPs, remain unclear. In this study, spatiotemporal variations in different types of MPs, ten ARGs (sul1, sul2, tetA, tetO, tetM, tetX, tetW, qnrS, ermB, and ermC), class 1 integron integrase (intI1) and transposon Tn916/1545 in three typical WWTPs were characterized. Sul1, tetO, and sul2 were the predominant ARGs in the targeted WWTPs, whereas the intI1 and transposon Tn916/1545 were positively correlated with most of the targeted ARGs. Saccharimonadales (4.15 %), Trichococcus (2.60 %), Nitrospira (1.96 %), Candidatus amarolinea (1.79 %), and SC-I-84 (belonging to phylum Proteobacteria) (1.78 %) were the dominant genera. Network and redundancy analyses showed that Trichococcus, Faecalibacterium, Arcobacter, and Prevotella copri were potential hosts of ARGs, whereas Candidatus campbellbacteria and Candidatus kaiserbacteria were negatively correlated with ARGs. The potential hosts of ARGs had a strong positive correlation with polyethylene terephthalate, silicone resin, and fluor rubber and a negative correlation with polyurethane. Candidatus campbellbacteria and Candidatus kaiserbacteria were positively correlated with polyurethane, whereas potential hosts of ARGs were positively correlated with polypropylene and fluor rubber. Structural equation modeling highlighted that intI1, transposon Tn916/1545 and microbial communities, particularly microbial diversity, dominated the dissemination of ARGs, whereas MPs had a significant positive correlation with microbial abundance. Our study deepens the understanding of the relationships between ARGs and MPs in WWTPs, which will be helpful in designing strategies for inhibiting ARG hosts in WWTPs.

Land finance, infrastructure investment and housing prices in China.

Housing prices in China have experienced rapid growth in recent decades, and land finance has long been discussed as an important factor in this growth. In this paper, we explore the interactions among housing prices, land transfer revenue and infrastructure investment from the perspective of government revenue and expenditure. Based on the panel data of 35 large and medium-sized cities in China from 2000 to 2017, the empirical results show that land transfer revenue, infrastructure investment and housing prices are causally related and result in positive feedback. The grouped regression results show that infrastructure investment has greater impacts on housing prices in eastern region cities than in the other cities. In contrast, in the central and western regions, land sales revenue has a greater impact on housing prices, indicating that cities in less-developed areas are more dependent on land finance than are those in more developed regions. Finally, we use the vector error correction model (VECM) to add control variables for robustness testing. The results show that land transfer income and infrastructure investment have a positive impact on housing prices. Our results provide some references for the stable development of housing markets in China.

A single-monomer derived linear-like PEI-co-PEG for siRNA delivery and silencing.

Polyethylenimines (PEIs) are commonly used as a vehicle to deliver and protect siRNA, but the strong interaction still remains to be modulated for efficient siRNA release and silencing. Herein, a single-monomer derived linear-like PEI-co-PEG (LPEI-co-PEG, P(2)) was synthesized to substantially enhance the siRNA release, but not affect the efficiency of protection. The linear-like copolymer (P(2)) was only synthesized from a single-monomer by intensive synchrotron X-ray irradiation within 5 min, randomly producing both PEI and PEG segments. The counterpart vehicle, LPEI (P(1)), was also synthesized for comparison. We found that the P(1) and P(2) were able to prevent siRNA against enzymatic degradation. Most importantly, efficient siRNA release (52%) was only observed in the siRNA/P(2) complexes and not in the siRNA/P(1) complexes (<5%), suggesting that the PEG segment may modulate the interaction between siRNA and P(2) segment. Specifically, P(2) as well as P(1) can emit photoluminescence; cancer cells exhibited a detectable photoluminescence after treatment with P(1) and P(2), indicative of their excellent transfection efficiency. Subsequently, the siGFP/P(2) complexes knocked down GFP with excellent efficiency (75%) above the siGFP/P(1) complexes (19%) and siGFP/Lipofectamine complexes (20%). Importantly, the siRNA with anti-VEGF function being associated with P(2) have been demonstrated an excellent efficiency in the suppression of tumor growth.

One-pot synthesis of linear-like and photoluminescent polyethylenimines for intracellular imaging and siRNA delivery.

Linear-like and photoluminescent polyethylenimines (LPEIs) were synthesized through a one-pot reaction within 5 min using synchrotron radiation for intracellular imaging and siRNA delivery.

Enhanced quantum yield of dendrimer-entrapped gold nanodots by a specific ion-pair association and microwave irradiation for bioimaging.

A specific ion-pair approach can be involved in precise control of the size of gold nanodots. The dendrimers with terminal amine and hydroxyl groups were a hydrophilic and hydrophobic microcavity-template, respectively, for trapping gold salts. The facile strategy can significantly enhance the quantum yield of gold nanodots from 20% to 62% after microwave irradiation.

Effects of peptidic antagonists of Grb2-SH2 on human breast cancer cells.

The growth factor receptor-bound protein Src homology 2 (Grb2-SH2) plays an important role in the oncogenic Ras signaling pathway, which involves in cell proliferation and differentiation. Therefore, the antagonist of Grb2-SH2 has become a potential target for developing anticancer agents. Recently, we discovered a peptide 1 (Fmoc-Glu-Tyr-Aib-Asn-NH(2)) with high affinity for the Grb2-SH2 domain by using surface plasmon resonance (SPR)-biosensor technology. Herein, we report the further design of the lead peptide 1 by addition of an Arg-Gly-Asp sequence to 1 to enhance binding to Grb2-SH2 and inducing apoptosis in cancer cells. Both the linear and cyclic analogs of the newly designed compound were prepared along with an analog in which the N(alpha)-Fmoc group was removed. These peptide analogs were assayed for their affinity for the Grb2-SH2, their antiproliferative effect on human breast cancer cells, their specificity for cancer cells, and their effects on cytotoxicity and the cell cycle. MCF-7 and MDA-MB-453 breast cancer cells were treated with various concentrations of each peptide. The cell viability and cytotoxicity of peptide-treated cells were determined by using the cell proliferation kit (3-[4, 5-dimethyl-2-thiazolyl]-2, 5-diphenyl-tetrazolium bromide, MTT) and cytotoxicity kit (lactate dehydrogenase, LDH), respectively. Effects of peptides on the cell cycle progression of cancer cells and apoptosis were analyzed by using flow cytometry. Results demonstrated that the peptide analog 2 (H-Arg-Gly-Asp-Glu-Tyr-Aib-Asn-Arg-Gly-Asp-NH(2)) had anti-proliferative effects on MCF-7 and MDA-MB-453 cells with an IC(50) of 45.7 microM and 47.4 microM, respectively. The cytotoxicity and percentage of sub-G1 in the cell cycle were increased in these cancer cells when cells were treated with higher concentration of the Arg-Gly-Asp-containing peptide 2. These results provide important information for the development of anti-cancer agents.