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p,p′-DDE, the main metabolite of DDT, isnotorious for its persistent and bioaccumulation. It has detrimentaleffects on the nervous system, while the mechanism is unclear. Wesought to investigate the mechanism of p,p′-DDE-inducedneurocytic apoptosis in PC12 cells by cytoflow and screen the potentialtarget gene by microarray and ELISA. Co-incubation with antagonistand SiRNA were applied to confirm the effect of the selected molecular.Results were also confirmed in zebrafish embryo. Results showed that p,p′-DDE induced apoptosis in PC12 cells at a concentrationof ≥2 × 10–5mol/L. Microarray resultsindicate that the TNF family plays a key role in p,p′-DDE-induced apoptosis among 84-apoptotic genes. In particular,the protein level of TNFα increased 4-fold. When incubated withTNFα antibody (infliximab), the number of apoptotic cells attenuatedby 50%, and both activities of caspases 8 and 9 decreased. SiRNA silencingof TNFα showed similar trends. Furthermore, p,p′-DDE induced neuronal apoptosis in zebrafish embryos in adose-dependent manner.This effect was partially reversed by infliximab,too. Overall, the present study herein indicated that the TNFαsignaling pathway is involved in p,p′-DDE-inducedneurocyte apoptosis. These data could be expanded to other cases ofOCP-induced apoptosis and would support the need for scientific interventionto address the neurotoxicity of these chemicals. [ABSTRACT FROM AUTHOR]

The long-term operation feature of enzymatic biofuel cell-based self-powered biosensor (EBFC-SPB) endows them with the potential to execute dual-signal biosensing without having to integrate an extra signal acquisition device. Herein, cobalt and manganese codoped CeO 2 nanospheres (CoMn-CeO 2 NSs) with glucose-oxidase-like and peroxidase-like activities have been developed as substrate-switched dual-channel signal transduction components in EBFC-SPB for a dual-signal assay of aflatoxin B1 (AFB1). The CoMn-CeO 2 NSs modified with aptamer are anchored to a complementary DNA-attached bioanode of EBFC-SPB by base complementary pairing, which catalyze the glucose oxidation together with the glucose oxidase (GOx) on the bioanode. Once the AFB1 appears, CoMn-CeO 2 NSs will be released from the bioanode due to the binding specificity of the aptamer, resulting in a decreased catalytic efficiency and the first declining stage of EBFC-SPB. Accompanied by the introduction of H 2 O 2 , the residual CoMn-CeO 2 NSs on the bioanode switch to peroxidase-like activity and mediate the production of benzo-4-chlorohexadienone (4-CD) precipitate, which increases the steric hindrance and yields another declining stage of EBFC-SPB. By assessing the variation amplitudes during these two declining stages, the dual-signal assay of AFB1 has been realized with satisfying results. This work not only breaks ground in dual-signal bioassays but also deepens the application of nanozymes in EBFC-SPB.

The peroxidase (POD)-like nanozyme typically requires the addition of exogenous H 2 O 2 . To address the limitation, previous work mainly adopted a cascade strategy for H 2 O 2 production. Herein, we propose a new light-driven self-cascade strategy to construct POD-like nanozymes without exogenous H 2 O 2 . The model nanozyme resorcinol-formaldehyde resin-Fe 3+ (RF-Fe 3+ ) is synthesized with the hydroxyl-rich photocatalytic material RF as the carrier to in situ chelate metal oxides, which can simultaneously achieve the functions of in situ H 2 O 2 generation under irradiation and substrate oxidation via POD-like behavior. Notably, RF-Fe 3+ exhibits high affinity to H 2 O 2 , attributed to the excellent adsorption ability and hydroxyl-rich feature of RF. Furthermore, the dual photoelectrode-assisted photofuel cell was further constructed with a high-power density of 120 ± 5 μW cm -2 based on the RF-Fe 3+ photocathode. This work not only demonstrates the new self-cascade strategy of in situ generation of catalysis substrates but also provides an opportunity to extend the catalytical field.

We described a novel palladium-catalyzed C-H glycosylation of indole or tryptophan for a one-pot stereoselective synthesis of 2,3-diglycosylindoles and tryptophan-C-glycosides. In this strategy, the use of air and base-free and ligand-free conditions provided a highly efficient route to construct C-glycosides. The method can be applied to a wide range of cost-effective and convenient glycosyl chloride donors. Mechanistic studies indicated that the indole 2,3-diglycosylation sequence was C3 and then C2.

An innovative 1,5-HAT cascade strategy has been advanced for the nickel-catalyzed distal arylation via cross-electrophile coupling. Through specific migration, the remote C(sp 3 )-H bond is regioselectively activated, and Ar-I as the available electrophile is used for the construction of the C(sp 3 )-C(sp 2 ) bond. This method also has broad applicability for benzylic and aliphatic N -fluorocarboxamides with yields up to 80%. Furthermore, a series of control experiments demonstrated that this reaction is probably initiated by a radical process.

The classic luminol-based electrochemiluminescence (ECL) platform generally suffers from self-decomposition of the coreactant (i.e., H 2 O 2 ) during the reaction process, seriously hampering the luminous signal stability, as well as its practical application. To address this issue, apart from the introduction of complex exogenous species, preoxidation of the luminophore, and electrocatalysis for ECL signal amplification, we proposed a novel ECL model to realize the signal enhancement via in situ self-photocatalytic generation of the coreactant H 2 O 2 . Interestingly, the luminescence of luminol was simultaneously utilized as the light source to promote the conversation of O 2 to H 2 O 2 with the assistance of the photocatalyst resorcinol-formaldehyde resin, which could further improve the luminescence of luminol in turn. In comparison with the traditional case, this new ECL model not only exhibited obvious signal amplification but also efficiently boosted its stability of signal output. To sum up, an exogenous coreactant-free, highly stable ECL platform was obtained via simply integrating the photocatalyst RF and the luminol-based system. This work will not only inspire the design of a new integrated ECL system with a coreactant translator but also provide an ingenious insight for the construction of a new generation of ECL models.

We described a novel palladium-catalyzed domino procedure for the preparation of (hetero)aryl thio/selenoglycosides. Readily available (hetero)aryl iodides and easily accessible 1-thiosugars/1-selenosugars are utilized as the substrates. Meanwhile, 10 types of sugars are quite compatible with this reaction with good regio- and stereoselectivity, high efficiency, and broad applicability (up to 89%, 53 examples). This method enables the straightforward formation of the C(sp 2 )-S/Se bond of (hetero)aryl thio/selenoglycosides.

Gaining chemical control over the thermodynamics and kinetics of photoexcited states is paramount to an efficient and sustainable utilization of photoactive transition metal complexes in a plethora of technologies. In contrast to energies of charge transfer states described by spatially separated orbitals, the energies of spin-flip states cannot straightforwardly be predicted as Pauli repulsion and the nephelauxetic effect play key roles. Guided by multireference quantum chemical calculations, we report a novel highly luminescent spin-flip emitter with a quantum chemically predicted blue-shifted luminescence. The spin-flip emission band of the chromium complex [Cr(bpmp) 2 ] 3+ (bpmp = 2,6-bis(2-pyridylmethyl)pyridine) shifted to higher energy from ca. 780 nm observed for known highly emissive chromium(III) complexes to 709 nm. The photoluminescence quantum yields climb to 20%, and very long excited state lifetimes in the millisecond range are achieved at room temperature in acidic D 2 O solution. Partial ligand deuteration increases the quantum yield to 25%. The high excited state energy of [Cr(bpmp) 2 ] 3+ and its facile reduction to [Cr(bpmp) 2 ] 2+ result in a high excited state redox potential. The ligand's methylene bridge acts as a Brønsted acid quenching the luminescence at high pH. Combined with a pH-insensitive chromium(III) emitter, ratiometric optical pH sensing is achieved with single wavelength excitation. The photophysical and ground state properties (quantum yield, lifetime, redox potential, and acid/base) of this spin-flip complex incorporating an earth-abundant metal surpass those of the classical precious metal [Ru(α-diimine) 3 ] 2+ charge transfer complexes, which are commonly employed in optical sensing and photo(redox) catalysis, underlining the bright future of these molecular ruby analogues.

The first synthesis of highly strained spirocyclobutane-pyrrolines via a palladium-catalyzed tandem Narasaka-Heck/C(sp 3 or sp 2 )-H activation reaction is reported here. The key step in this transformation is the activation of a δ-C-H bond via an in situ generated σ-alkyl-Pd(II) species to form a five-membered spiro-palladacycle intermediate. The concerted metalation-deprotonation (CMD) process, rate-determining step, and energy barrier of the entire reaction were explored by density functional theory (DFT) calculations. Moreover, a series of control experiments was conducted to probe the rate-determining step and reversibility of the C(sp 3 )-H activation step.

Six new polyketides named paraverrucsins A-F ( 1 - 6 ) with oxabicyclic and dioxatricyclic skeletons, together with eight known metabolites ( 7 - 14 ), were discovered and isolated from the fermentation medium of Paraphaeosphaeria verruculosa . Paraverrucsin A-C possessed a novel decarboxylated skeleton compared with that of trichocladinols. Their structures were elucidated by extensive spectral analysis and DP4+ calculations. Paraverrucsins B/C and D/E were isolated as a mixture for the mutarotation occurred at C-2. Paraverrucsins B/C, D/E, F/trichocladinol B, 8 , and 9 displayed antifeedant activities against silkworm larvae, with antifeedant index percentages ranging from 62.5 to 93.0%, at a concentration of 50 μg/cm 2 . Among them, Paraverrucsins B/C and 9 had EC 50 values at 13.9 and 18.2 μg/cm 2 . Most compounds showed antifungal activities against phytopathogenic fungi with minimum inhibitory concentration (MIC) values of 16-64 μg/mL. Coculture of P. verruculosa and host plant Dendrobium officinale leads to the enhancement of antifeedant and antiphytopathogenic activities . Compounds 1 , 2 / 3 , 4 / 5 , 6 / 14 were tested for cytotoxicity against five human carcinoma cell lines, HL-60, A549, MCF-7, SW480, and SMMC-7721, while they exhibited selected cytotoxicity against SW480 with inhibition ratios of 32-38% at a concentration of 40 μM., Competing Interests: The authors declare no competing financial interest., (© 2020 American Chemical Society.)

This report describes the first example of palladium-catalyzed ortho -C-H glycosylation/ ipso -alkenylation of aryl iodides, and the easily accessible glycosyl chlorides are used as a glycosylation reagent. The reaction is compatible with the functional groups of the substrates, and a series of C-aryl glycosides have been synthesized in good to excellent yield and with excellent diastereoselectivity. It is found that a cheap 5-norbornene-2-carbonitrile as a transient mediator can effectively promote this reaction. In addition, ipso -arylation and cyanation were also realized by the strategy.

Despite the ubiquity of organophosphate flame retardants (OPFRs) metabolites in the biota, the endocrine disrupting potency has not been well examined. Herein, we chose three primary metabolites of OPFRs (BCIPP, BDCIPP, and DPHP) to investigate their potential endocrine disrupting effects by in vitro, in vivo, and in silico assays. Three metabolites were agonistic to rat estrogenic receptor alpha (ERα) and antagonists to human mineralocorticoid receptor (MR). BCIPP exerted endocrine disrupting effect contrasting to the negative response of its parental compound. It also poses the strongest binding capacity to ERα among the tested compounds. Both BCIPP and BDCIPP upregulated the genes encoded for estrogenic synthesis enzymes in H295R cells, including 17βHSD and CYP19 . All three compounds stimulated the transcription of CYP11B1 , whereas BCIPP and DPHP also triggered CYP11B2 , encoding for corticoid production. BDCIPP inhibits genes for progesterone synthesis including CYP11A1 , STAR , and 3-βHSD . The induction of mortality and low hatchability of zebrafish embryo were ranked as BCIPP ≥ BDCIPP > DPHP. All compounds lead to malformation of zebrafish larvae. Both of the hypothalamic-pituitary-adrenocortical and hypothalamic-pituitary-gonadal axes were disrupted, with the highest impact by BCIPP. Altogether, the data clarified OPFRs metabolites may produce comparable or even higher endocrine disrupting effects than OPFRs.