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Escherichia coli (E. coli) O157:H7 is a major foodborne and waterborne pathogen that can threaten human health. Due to its high toxicity at low concentrations, it is crucial to establish a time-saving and highly sensitive in situ detection method. Herein, we developed a rapid, ultrasensitive, and visualized method for detecting E. coli O157:H7 based on a combination of Recombinase-Aided Amplification (RAA) and CRISPR/Cas12a technology. The CRISPR/Cas12a-based system was pre-amplified using the RAA method, which showed high sensitivity and enabled detecting as low as ~1 CFU/mL (fluorescence method) and 1 × 102 CFU/mL (lateral flow assay) of E. coli O157:H7, which was much lower than the detection limit of the traditional real-time PCR technology (103 CFU/mL) and ELISA (104~107 CFU/mL). In addition, we demonstrated that this method still has good applicability in practical samples by simulating the detection in real milk and drinking water samples. Importantly, our RAA-CRISPR/Cas12a detection system could complete the overall process (including extraction, amplification, and detection) within 55 min under optimized conditions, which is faster than most other reported sensors, which take several hours to several days. The signal readout could also be visualized by fluorescence generated with a handheld UV lamp or a naked-eye-detected lateral flow assay depending on the DNA reporters used. Because of the advantages of being fast, having high sensitivity, and not requiring sophisticated equipment, this method has a promising application prospect for in situ detection of trace amounts of pathogens.

Developing low-cost and efficient materials for dye pollutant removal under mild condition remains a great challenge. Here K

Accurate determination of antibiotic resistance genes (ARGs) in environmental DNA molecules (eDNA) is challenging owing to its low abundance in the aquatic environment. Here we report a facile and cost-efficient approach to extract trace amount of eDNAs in the aquatic environment using LnPO

Accurate determination of antibiotic resistance genes (ARGs) in environmental DNA molecules (eDNA) is challenging owing to its low abundance in the aquatic environment. Here we report a facile and cost-efficient approach to extract trace amount of eDNAs in the aquatic environment using LnPO4 nanomaterials. Among the nanomaterials, less crystalline TbPO4 nanoneedles was identified as the most prominent candidate for long stranded DNA and short stranded DNA with adsorption efficiency above 97%. The adsorbed DNA was washed off from TbPO4 nanoneedles by optimized eluant (85% PBS, 15% EtOH, 4 g/L glycine, pH 10.0) with an optimal DNA recovery of 78.83%. Our approach showed a comparable or better eDNA extraction efficiency than a commercial extraction method for different environmental samples, but 89% less cost. The high purity of the extracted eDNA was demonstrated by a high A260/280 ratio. Using qPCR experiment, the occurrence of six common ARGs in the eDNA were detected with abundance ranging from 4.06 × 103 to 3.51 × 109 copies/L in river samples. This specific DNA capturer is valuable for the evaluation of spatial and temporal dynamic of ARGs pollution to provide insight into the potential risk with regard to the human health.

Low-cost MnO2 has been vigorously investigated in the field of catalysis. However, high amount of MnO2 usually needs to be used in the disinfection process owing to their low photocatalytic activity. In this work, modification of MnO2 with zeolitic imidazole framework-8 (ZIF-8) for improving the photocatalytic bactericidal performance was explored for the first time. Specifically, MnO2/ZIF-8 exhibited complete inactivation of multi-drug resistant Escherichia coli (E. coli) at a low concentration (3.24 μg/mL) with simulated solar irradiation. The 1O2 rather than O2− or OH was identified as the major reactive species for the bacterial inactivation. Mechanistic studies indicated that the superior bactericidal property of MnO2/ZIF-8 than the pristine material could be ascribed to the increased surface oxygen vacancies (OVs) amount and an inhibited electron and hole recombination. This study provides a novel type of photocatalyst for antibacterial application and may shed light on designing MnO2 based low-cost nanocomposites with photocatalytic bactericidal capability for the practical water disinfection treatment.

Di-2-ethylhexyl phthalate (DEHP) which belongs to phthalatic-acid esters, is a kind of harmful, global environmental pollutants. It is a known endocrine disrupting chemical and male reproductive toxicant. However, the mechanism by which DEHP exposure result in male reproductive toxicity is still unclear. To elucidate the productive toxicity mechanism of DEHP, we attemptted to investigate oxidative stress, apoptotic effects, mRNA and protein expression of apoptosis-associated genes including FasL, caspase-3, and caspase-8 in GC-2spd (mouse spermatogenic cells). The results showed that, with the increase of DEHP concentration, cell apoptosis rate increased; the activities of relation index of oxidative stress such as malondialdehyde (MDA), superoxide dismutase (SOD) and glutatione peroxidase (GSH-PX) changed significantly; the mRNA and protein expression levels of FasL, caspase-3, -8, altered obviously. These results suggested that DEHP could induce apoptosis of GC-2spd cells through oxidative stress and FasL-dependent pathway.

Di(2-ethylhexyl) phthalate (DEHP), a plasticizer of synthetic polymers, is a well-known endocrine disrupting chemical (EDC) and reproductive toxicant. Addressing the unclear mechanism of DEHP-induced reproductive dysfunction, this study used GC-2spd cells to investigate the molecular mechanism involved in the DEHP-induced toxicity in the male reproductive system. The results indicated that the apoptotic cell death was significantly induced by DEHP exposure over 100 μM. Furthermore, DEHP treatment could induce oxidative stress in GC-2spd cells involving in the decrease of superoxide dismutase (SOD) activity (200 μM) and glutathione peroxidase (GSH-Px) activity (50 and 100 μM). In addition, DEHP induction also caused the elevated ratios of Bax/Bcl-2, release of cytochrome c and decomposition of procaspase-3 and procaspase-9 in GC-2spd cells. Taken together, our work provided the evidence that DEHP exposure might induce apoptosis of GC-2spd cells via mitochondria pathway mediated by oxidative stress. © 2016 Wiley Periodicals, Inc. Environ Toxicol 32: 1055-1064, 2017.

Di-(2-ethylhexyl) phthalate (DEHP) is a widely used environmental endocrine disruptor. Many studies have reported that DEHP exposure causes reproductive toxicity and cells apoptosis. However, the mechanism by which DEHP exposure causes male reproductive toxicity remains unknown. This study investigated the role of the testicular orphan nuclear receptor4 (TR4)/Bcl-2 pathway in apoptosis induced by DEHP, which resulted in reproductive damage. To elucidate the mechanism underpinning the male reproductive toxicity of DEHP, we sought to investigate apoptotic effects, expression levels of TR4/ Bcl-2 pathway in GC-2spd cells, including TR4, Bcl-2 and caspase-3. GC-2spd cells were exposed to various concentrations of DEHP (0, 50, 100, or 200 μM). The results indicated that, with the increase of the concentrations of DEHP, the survival rate of cell decreased gradually. DEHP exposure at over 100μM significantly induced apoptotic cell death. DEHP decreased SOD and GSH-Px activity in 200μM group. Compared to the control group, the mRNA levels of caspase-3 increased significantly, however, Bcl-2 mRNA decreased (P

Functionalized 2,3-disubstituted-1,3-butadienes were readily prepared by reacting functionalized organozinc compounds with 1,4-dichloro-2-butyne or 1,4-ditosyloxy-2-butyne mediated by Cu(I) salts.