Product identification and toxicity change during oxidation of methotrexate by ferrate and permanganate in water

Accompanying an annual increase in cancer incidence,the global use of anticancer drugs has remarkably increased with their worldwide environmental prevalence and ecological risks.In this study,the oxidation of methotrexate(MTX),a typical anticancer drug with ubiquitous occurrence and multi-endpoint toxicity,by ferrate(VI)(Fe(VI))and permanganate(Mn(VII)))was investigated in water.Fe(VI)exhibited a higher reactivity with MTX(93.34 M^(−1) s^(−1))than Mn(VII)(3.01 M^(−1) s^(−1)) at pH 8.0.The introduction of Cu(II)and Fe(III)at 1.0 mM improved the removal efficiency of 5.0μM MTX by 100.0μM Fe(VI)from 80%to 95%and 100%after 4 min,respectively.Seven oxidized products(OPs)were identified during oxidative treatments,while OP-191 and OP-205 were characterized as specific products for Fe(VI)oxidation.Initial ketonization of the L-glutamic acid moiety and cleavage of the peptide bond of MTX were proposed.Additionally,a multi-endpoint toxicity evaluation indicated no genotoxicity,neurotoxicity,or endocrine-disrupting effects of MTX and its OPs.Particularly,serious developmental toxicity in zebrafish larvae was observed in the treated MTX solutions.Based on the acute and chronic aquatic toxicity prediction,OP-190,OP-192,OP-206,and OP-208 were deemed toxic or very toxic compared to harmful MTX.Furthermore,the reduced biodegradability index from 0.15(MTX)to−0.5 to−0.2(OP-192,OP-206,and OP-468)indicated the formation of lower biodegradable OPs.Overall,this study suggests that Fe(VI)and Mn(VII)oxidation are promising treatments for remediating anticancer drug-contaminated water.However,the environmental risks associated with these treatments should be considered in the evaluation of water safety.

Affinity maturation of anti-TNF-alpha scFv with somatic hypermutation in non-B cells

Activation-induced cytidine deaminase(AID)is required for the generation of antibody diversity through initiat-ing both somatic hypermutation(SHM)and class switch recombination.A few research groups have success-fully used the feature of AID for generating mutant li-braries in directed evolution of target proteins in B cells in vitro.B cells,cultured in suspension,are not con-venient for transfection and cloning.In this study,we established an AID-based mutant accumulation and sorting system in adherent human cells.Mouse AID gene was first transfected into the human non-small cell lung carcinoma H1299 cells,and a stable cell clone(H1299-AID)was selected.Afterwards,anti-hTNF-αscFv(ATscFv)was transfected into H1299-AID cells and ATscFv was displayed on the surface of H1299-AID cells.By 4-round amplification/flow cytometric sorting for cells with the highest affinities to hTNF-alpha,two ATscFv mutant gene clones were isolated.Compared with the wild type ATscFv,the two mutants were much more efficient in neutralizing cytotoxicity of hTNF-alpha.The results indicate that directed evolution by somatic hypermutation can be carried out in adherent non-B cells,which makes directed evolution in mammalian cells easier and more efficient.

Targeted deletion of mouse Rad1 leads to deficient cellular DNA damage responses

The Rad1 gene is evolutionarily conserved from yeast to human.The fission yeast Schizosaccharomyces pombe Rad1 ortholog promotes cell survival against DNA damage and is required for G_(2)/M checkpoint activation.In this study,mouse embryonic stem(ES)cells with a targeted deletion of Mrad1,the mouse ortholog of this gene,were created to evaluate its function in mammalian cells.Mrad1^(−/−)ES cells were highly sensitive to ultraviolet-light(UV light),hydroxyurea(HU)and gamma rays,and were defective in G_(2)/M as well as S/M checkpoints.These data indicate that Mrad1 is required for repairing DNA lesions induced by UV-light,HU and gamma rays,and for mediating G_(2)/M and S/M checkpoint controls.We further demonstrated that Mrad1 plays an important role in homologous recombination repair(HRR)in ES cells,but a minor HRR role in differentiated mouse cells.

A data-driven framework to predict the morphology of interfacial Cu6Sn5 IMC in SAC/Cu system during laser soldering

A data-driven approach combining together the experimental laser soldering,finite element analysis and machine learning,has been utilized to predict the morphology of interracial intermetallic compound(IMC) in Sn-xAg-yCu/Cu(SAC/Cu) system.Six types of SAC solders with varying weight proportion of Ag and Cu,have been processed with fiber laser at different magnitudes of power(30-50 W) and scan speed(10-240 mm/min),and the resultant IMC morphologies characterized through scanning electron microscope are categorized as prismatic and scalloped ones.For the different alloy composition and laser parameters,finite element method(FEM) is employed to compute the transient distribution of temperature at the interface of solder and substrates.The FEM-generated datasets are supplied to a neural network that predicts the IMC morphology through the quantified values of temperature dependent Jackson parameter(αJ).The numerical value of αJ predicted from neural network is validated with experimental IMC morphologies.The critical scan speed for the morphology transition between prismatic and scalloped IMC is estimated for each solder composition at a given power.Sn-0.7 Cu having the largest critical scan speed at 30 W and Sn-3.5 Ag alloy having the largest critical scan speed at input power values of 40 W and 50 W,thus possessing the greatest likelihood of forming prismatic interfacial IMC during laser soldering,can be inferred as most suitable SAC solders in applications exposed to shear loads.