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NAD(P)H is a vital hydrogen donor and electron carrier involved in numerous biological processes. The development of small-molecule tools for intravital imaging of NAD(P)H is significant for further exploring their pathophysiological roles. Herein, we rationally designed a fluorescent probe NADH-R by a simple graft of pyridiniumylbutenenitrile on a 1-methylquinolinium moiety in the 3-position. Benefited from the reduction of quinolinium by NAD(P)H, this probe releases the free push-pull fluorophore NADH-RH, allowing a turn-on red-emitting fluorescence response together with an ultralow detection limit of 12 nM. Under the assistance of the probe, we first monitored exogenous and endogenous generation of NAD(P)H in living cells, subsequently observed dynamic changes of NAD(P)H levels in living cells under different metabolic perturbations, and finally visualized the declined NAD(P)H levels in live mouse brain in a stroke model. Unexpectedly, the time-dependent colocalization experiment revealed that the probe reacts with mitochondrial NAD(P)H, followed by a shift of its reduced product NADH-RH from mitochondria to the nucleus, highlighting that NADH-RH is a novel nucleus-directed dye scaffold, which would facilitate the development of nucleus-targeting fluorescent probes and drugs.

Thioredoxin reductase (TrxR) is a pivotal antioxidant enzyme, but there remains a challenge for its fast imaging. This work describes the combination of a hydroxyl styrylpyridinium scaffold as the push-pull fluorophore with a carbonate-bridged 1,2-dithiolane unit as the reaction site to develop a fast mitochondrial TrxR2 probe, DSMP . It manifested a plethora of excellent properties including a rapid specific response (12 min), large Stokes shift (170 nm), ratiometric two-photon imaging, favorable binding with TrxR ( K m = 12.5 ± 0.2 μM), and the ability to cross the blood-brain barrier. With the aid of DSMP , we visualized the increased mitochondrial TrxR2 activity in cancer cells compared to normal cells. This offers the direct imaging evidence of the connection between the increased TrxR2 activity and the development of cancer. Additionally, the probe allowed the visualization of the loss in TrxR2 activity in a cellular Parkinson's disease model and, more importantly, in mouse brain tissues of a middle cerebral artery occlusion model for ischemic stroke.

Reprograming of energy metabolism is a major hallmark of cancer, but its effective intervention is still a challenging task due to metabolic heterogeneity and plasticity of cancer cells. Herein, we report a general redox-based strategy for meeting the challenge. The strategy was exemplified by a dietary curcumin analogue (MitoCur-1) that was designed to target mitochondria (MitoCur-1). By virtue of its electrophilic and mitochondrial-targeting properties, MitoCur-1 generated reactive oxygen species (ROS) more effectively and selectively in HepG2 cells than in L02 cells via the inhibition of mitochondrial antioxidative thioredoxin reductase 2 (TrxR2). The ROS generation preferentially mediated the energy crisis of HepG2 cells in a dual-inhibition fashion against both mitochondrial and glycolytic metabolisms, which could hit the metabolic plasticity of HepG2 cells. The ROS-dependent energy crisis also allowed its preferential killing of HepG2 cells (IC 50 = 1.4 μM) over L02 cells (IC 50 = 9.1 μM), via induction of cell-cycle arrest, apoptosis and autophagic death, and its high antitumor efficacy in vivo, in nude mice bearing HepG2 tumors (15 mg/kg). These results highlight that inhibiting mitochondrial TrxR2 to produce ROS by electrophiles is a promising redox-based strategy for the effective intervention of cancer cell energy metabolic reprograming.

Glutathione (GSH), an extremely important antioxidant, is a major participant in maintaining redox homeostasis and tightly associated with various clinical diseases. Thus, accurate and rapid detection of intracellular GSH is imperative to elucidate its role in physiological and pathological processes. Herein, by modifying 2-(2'-hydroxyphenyl) benzothiazole (HBT) scaffold, we developed an excited-state intramolecular proton transfer (ESIPT)-based fluorescent probe BTFMD for tracking GSH, which exhibited good selectivity, excellent water solubility, a large Stokes shift (181 nm) and fast response rate (within 10 min). Furthermore, the probe was successfully applied for imaging of endogenous GSH in live cells and zebrafish, and probing into the role of GSH in the development of cancer and Parkinson's disease., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2020 Elsevier B.V. All rights reserved.)

The present study aimed to investigate the association between five common small nucleotide polymorphisms (SNPs) in the VEGF gene and the risk of osteosarcoma. An additional aim was to investigate the role of these five SNPs on the prognosis of osteosarcoma. A total of 186 patients with osteosarcoma and 186 age- and sex-matched healthy controls were enrolled into the present study. A polymerase chain reaction-restriction fragment length polymorphism assay was conducted to determine the incidence of the VEGF-2578 C/A, -1156 G/A, +1612 G/A, +936 C/T and -634 G/C polymorphisms. Conditional logistic regression analyses revealed that individuals carrying the -634 GG genotype possessed a significantly increased risk of osteosarcoma, with an adjusted odds ratio [(95% confidence interval (CI)] of 2.00 (1.07-3.75). In the Cox proportional hazards model, subsequent to adjusting for potential confounding factors, patients with osteosarcoma carrying the -634 GG genotype were found to demonstrate a shorter overall survival time (hazard ratio, 3.10; 95% CI, 1.17-8.38). The VEGF-634 G/C polymorphism may therefore be used as a genetic marker for the prediction of the risk and clinical outcome of osteosarcoma.

The biogeochemical cycle of sulfur can directly affect the speciation transformation of heavy metals in soils and their accumulation in plants. The toxicity of heavy metals in plants can be alleviated by their complexation with sulfur compounds like phytochelatins or metallothiones, consisting of the major mechanisms of phytodetoxification. Sulfur deficiency is becoming one of the limiting factors that influence Chinese agricultural production. Although the applications of sulfur fertilizer in soil have received much attention in recent years, the interaction mechanism of heavy metal with sulfur metabolism has not been studied extensively. In this paper, we reviewed current research advance on the impact of sulfur on the speciation transformation of soil heavy metals and their accumulation in plants, discussed the effect of sulfur on the detoxification mechanism of heavy metal in plants and provided further research prospective in this field.

Contamination of soils by lead (Pb) is of widespread occurrence because of the industrialization, urbanization, mining, and many other anthropogenic activities. It is urgent and necessary for scientists to uncover the mechanisms of uptake, translocation, accumulation and detoxification of Pb in plants for the following two reasons. First, it helps target and regulate the key process of Pb uptake by crops and vegetables and minimize the threat of Pb introduction to the food chain. Second, it helps cultivate Pb hyperaccumulating plants that can absorb and sequester excessive amounts from contaminated soils in their biomass without incurring damage to basic metabolic functions. The purpose of this review was to summarize the research advances in uptake, translocation and accumulation of Pb in plants and address the mechanisms by which plants or plant systems detoxify Pb. The further researches on the foliar uptake, the interactions between soil components and plant cell wall, as well as the integrated technologies for phytoremediation of Pb-contaminated soils were prospected.

A hydroponics experiment combined with subcellular fractionation and sequential extraction was conducted to study the Pb concentration in different organs of two tea plant varieties (Longjing 43 and Yingshuang) and the Pb subcellular distribution and chemical forms in the roots of the varieties. Under Pb stress, the root system of the two varieties had different features in morphology. With the increasing concentration of Pb in culture solution, the Pb concentration in Longjing 43 young leaves increased, but that in Yingshuang' s had no significant variation. A marked difference was observed in the Pb subcellular distribution and its chemical forms in roots between the two varieties under Pb stress. In Longjing 43 roots, all subcellular fractions except soluble ones had a lower Pb concentration at low Pb stress, and all the subcellular fractions except cell wall ones had a higher Pb concentration at higher Pb stress, compared with those in Yingshuang's. In Longjing 43 roots, the HAc-extractable Pb occupied the greatest proportion, followed by NaCl-extractable Pb, HCl- and H2O- extractable Pb, and ethanol-extractable Pb; while in Yingshuang's, NaCl-extractable Pb had the greatest proportion, followed by HAc-extractable Pb, HCl- and H2O-extractable Pb, and ethanol-extractable Pb. Based on these findings, tea plant variety Yingshuang was likely to possess a higher tolerance to Pb than Longjing 43 did.

The prokaryotic microbial diversity of the ancient salt deposits in the Kunming Salt Mine, PR China was investigated using PCR-DGGE and rRNA approaches. Total community DNA was extracted and purified by a direct method, which yielded amplified DNA of high molecular weight for samples. A variable region of 16S rRNA gene was then amplified by PCR with bacterial and archaeal primers and analyzed by denaturing gradient gel electrophoresis (DGGE). Twenty-seven major bands were detected in the bacterial DGGE profile of the sample, but only one band of pure culture strains of bacteria isolated from the Kunming Salt Mine matched with one band of sample. No band of pure culture strains of archaea isolated from the Kunming Salt Mine matched with 18 major bands of sample. The results indicated that most of microbes in this environment are likely uncultivable. Clones on the plate were not the predominant species in the community. Two 16S rRNA gene clone libraries (bacteria and archaea) were also constructed, and 36 and 20 clones were selected for amplified ribosomal DNA restriction analysis (ARDRA). ARDRA with enzymes Afa I, Hha I, Hae III revealed 10 bacterial operational taxonomic units (OTUs), with three most abundant OTUs accounting for 38.9%, 25.0%, 16.7% of all the bacterial 16S rDNA clones, respectively. The remaining 7 OTUs presented at low levels, were represented by a single clone. Eight archaeal OTUs were obtained but no predominant OTUs. Some clones were sequenced and each sequence was compared with all nucleotide sequences in GenBank database. Examination of 16S rDNA clones showed that the ancient salt deposits in the Kunming Salt Mine contained a phylogenetically diverse population of organisms from the Bacteria domain with members of three major lineages represented: alpha-proteobacteria, gamma-Proteobacteria and Actinobacteria, especially Pseudomonas. Surprisingly, we recovered a variety of sequence closely related to Actinobacteria which was not found in other salt deposits. All of archaeal clones are from Halorubrum, Haloterrigena and uncultured archaea. The results of DGGE and clone library profiling analysis both indicated that microbial community of the Kunming Salt Mine had higher diversity. In this initial survey, our polyphasic approaches demonstrated that novel and uncultured microbes thrive in the ancient salt deposits of the Kunming Salt Mine. Molecular analysis of the microbial diversity in salt deposits provides foundation for better application of microbial resources.

In order to understand the diversity of culturable bacteria, 44 bacteria strains inhabiting brines and salt crystals in the Kunming Salt Mine, P. R. China were isolated and cultured. Results showed that the numbers of the bacteria isolated from salt crystals (3.1 x 10(3) - 3.7 x 10(6) CFU/g) were higher than those from brines (1.3 - 6.3 x 10(3) CFU/L). A neighbor-joining tree of the partial 16S rDNA sequences (about 600bp of 5'-end) showed that 44 strains were phylogenetically clustered into 4 major groups and 44 distinct lineages or species (the similarities of 16S rDNA sequences <97%): 24 strains of Firmicutes (54.6%), 2 strains of alpha-Proteobacteria (4.6%), 4 strains of gamma-Proteobacteria (9.1%) and 14 strains of Actinobacteria (31.7%). Strains of the genus Bacillus (26.1% and 59.9%) were the most predominant microorganisms among brines and salt crystals. Additionally, seven potential novel species were found, based on the similarities of 16S rDNA sequences to those of previously published species, and seven strains with bioactivities against pathogenic microorganisms were isolated. The conclusion is that there are a number of novel species and bioactive strains, as well as great diversity in Kunming Salt Mine.