Search

Whether it is possible to create suitable plants for cadmium phytoremediation by introducing Datura stramonium L. genes into tobacco (Nicotiana tabacum L.) remains unclear. Hydroponic experiments were performed on N. tabacum L. var. MTLY, a newly developed hybrid variety, and the parents. Seedlings at the six-leaf stage were treated with 0 (control), 10 µM, 180 µM and 360 µM CdCl2 for 7 days, and their differences in Cd tolerance and accumulation and physiological and metabolic responses were evaluated. When subjected to 360 µM Cd, the growth of "MTLY", in terms of the dry weight, plant height and root length, was obviously better than N. tabacum L. var. LY2 (female parent). In contrast to D. stramonium (male parent) and "LY2", "MTLY" accumulated more Cd in shoots (127.6–3837.1 mg kg−1) and roots (121.6–1167.7 mg kg−1). Moreover, unlike "LY2", "MTLY" could accumulate more Cd in its shoots than roots. Its bioconcentration factor (BCF) and translocation factor (TF) values reached 95.9–149.7 and 1.0–3.5, respectively, which were far greater than those of "LY2". High-dose Cd stress significantly increased reactive oxygen species (ROS) and malondialdehyde (MDA) levels and decreased chlorophyll contents in tobacco seedlings, especially in "LY2". Various enzymatic and non-enzymatic antioxidants in the three materials showed different responses to Cd stress. The change of the phenolic compounds and alkaloids in "MTLY" was basically similar to that in D. stramonium, but their levels were apparently higher than those in "LY2". Results indicated that distant hybridization could be one of the effective methods for introducing metal-hyperaccumulator genes into a high biomass species, which contributed to enhancing the Cd tolerance, accumulation and detoxification in tobacco. This study has great significance in obtaining elite germplasm for phytoremediation. The exact mechanisms in molecules and genetics and the practical effectiveness in cadmium-contaminated soil remain to be further elucidated. [ABSTRACT FROM AUTHOR]

Background: Acinetobacter baumannii (A. baumannii) is an opportunistic pathogen and has emerged as one of the most troublesome pathogens. Drug resistance in A. baumannii has been reported on a global scale. Minocycline was found to be active against multi-drug resistant A. baumannii and was approved by the FDA for the infections caused by sensitive strains of A. baumannii. However, the emergence of minocycline resistance and its toxic effects still need to be addressed. Therefore, this study aimed to evaluate the synergistic effects of metformin combined with minocycline on minocycline-resistant A. baumannii. Results: The effect of metformin on the antibacterial activity of minocycline was determined by checkerboard and time-killing assay. Further, it was observed by biofilm formation assay that metformin combination with minocycline can inhibit the formation of biofilm. Outer membrane integrity, membrane permeability, membrane potential and reactive oxygen species (ROS) were monitored to explore the underlying synergistic mechanisms of metformin on minocycline. And the results shown that metformin can destroy the outer membrane of A. baumannii, enhance its membrane potential, but does not affect the membrane permeability and ROS. Conclusion: These findings suggested that the combination of metformin and minocycline has the potential for rejuvenating the activity of minocycline against minocycline-resistant A. baumannii. [ABSTRACT FROM AUTHOR]

For the preparation of carbon dots (CDs), a variety of carbon sources and synthetic protocols are available which endow CDs with variable and unpredictable properties. In the present study, three CDs were developed with ionic liquid 1-butyl-3-methylimidazolium dicyanamide as the precursor through ethanol-thermal and hydrothermal strategies, termed as E-CDs and H-CDs, respectively. The features of these carbon dots, i.e., their physicochemical and optical properties, their interactions with bovine serum albumin (BSA) as well as their imaging capability were investigated with respect to the CDs prepared with microwave assisted approach (W-CDs). E-CDs and H-CDs were demonstrated to exhibit similar framework structures and optical properties, and they exhibited larger particle-sizes than that of W-CDs. In addition, the increase of ethanol-thermal and hydrothermal reaction time strengthened the quantum yields of the CDs and promoted their binding capability with BSA. E-CDs and H-CDs showed similar cytotoxicity on normal (LX-2) and cancer (SK-Hep-1) cells. We further found that these CDs may readily enter the cells within 5 min, while the fluorescence of hydrophilic E-CDs and H-CDs was very weak with respect to that of hydrophobic W-CDs in cell imaging. On the other hand, all the CDs exhibited little impact on the level of intracellular reactive oxygen species. The present study is conducive to guide the preparation of suitable carbon dots for different application scenarios. [Display omitted] • BmimDCN was used as precursor to prepare CDs through solvothermal methods. • Ethanol solvent and increased reaction time promoted QYs of CDs and binding to BSA. • CDs showed similar cytotoxicity on liver normal and cancer cells. • CDs had little impact on the level of intracellular ROS. • The cancer cells could take up the CDs within 5 min, and emitted weak fluorescence. [ABSTRACT FROM AUTHOR]

Hepatocellular carcinoma (HCC) is resistant to current immunotherapy. This poor outcome mainly results from the immunosuppressive characteristics of tumor microenvironment (TME). Accumulating evidence indicates that some chemotherapy agents trigger immunogenic cell death (ICD), providing a promising strategy to remodel the immunosuppressive TME. The role of Plumbagin (PLB, a naphthoquinone compound from Plumbago zeylanica L.) as the ICD inducer for HCC cells was confirmed in this study. Dihydrotanshinone I (DIH, a phenanthraquinone compound of Salvia miltiorrhiza) functioned as the ICD enhancer by generating the reactive oxygen species (ROS). A poly(D,L-lactic- co -glycolic acid) (PLGA)-based nanoparticle (NP) was used to co-encapsulate PLB, DIH and NH 4 HCO 3 (a pH sensitive adjuvant). This NP was further coated with the mannose-inserted erythrocyte membrane to produce a nanoformulation. This nanoformulation significantly increased the half-life and tumor targeting of two drugs in orthotopic HCC mice, generating chemo-immunotherapeutic effects for reversal of immunosuppressive TME. Consequently, the biomimetic nanoformulation loaded with low doses of PLB and DIH achieved significantly longer survival of HCC mice, without causing toxic signs. Our study demonstrates a promising strategy for remodeling the immunosuppressive TME of liver cancer. Co-delivery of Plumbagin and Dihydrotanshinone I using biomimetic NPs for reversal of immunosuppressive TME in HCC. [Display omitted] • Plumbagin functions as an ICD inducer against HCC. • Dihydrotanshinone I generates ROS to enhance the ICD effects of PLB. • A biomimetic co-nanoformulation reverses the immunosuppressive tumor microenvironment of HCC. [ABSTRACT FROM AUTHOR]

Lactobacillus plantarum is a catalase-negative species and distributes in human intestinal tracts. However, the cytoprotective effects of the catalase-activated L. plantarum strain have yet to be exploited against reactive oxygen species (ROS). Here, a catalase-activated L. plantarum CGMCC 6888 (CatA+) was obtained using exogenous added heme. The scavenging free radical abilities of this strain were obviously increased. Moreover, the activated catalase A in L. plantarum CGMCC 6888 endowed the intestinal epithelium NCM460 with lower ROS content after degrading H2O2. In addition, the transcription levels of Nrf2 and Nrf2-related antioxidant enzyme genes (HO-1, GCLC, NQO-1 and TXNRD1) and tight junction protein genes (ZO-1, OCLN, and JAM-1) were upregulated significantly when co-incubated with CGMCC 6888/CatA+. This work confirmed that the catalase A conferred L. plantarum with the strong protection effects in the intestinal epithelial cells against ROS. [ABSTRACT FROM AUTHOR]

Pseudorabies virus (PRV) is an alpha herpesvirus that causes pseudorabies. After 2011, new and more pathogenic PRV variants have caused huge economic losses to the pig industry. In addition, people have been reported to be infected with PRV. Therefore, developing new anti-PRV drugs is of great significance. In this study, we investigated the anti-PRV activity of Hippophae rhamnoides polysaccharides (HRP) in vitro. We found that HRP could significantly inhibit the infectivity of the PRV XJ5 strain in PK15 cells. Addition of HRP at different times of the virus life cycle mainly led to the inhibition of the adsorption and entry of virus into the cells. Our results revealed that HRP can reduce the malondialdehyde (MDA) content and reactive oxygen species (ROS) level in PRV-infected PK15 cells and increase the superoxide dismutase (SOD) activity. These results suggested that HRP can reduce PRV infection-induced oxidative stress. Therefore, HRP may act as an antiviral drug against newly emerging PRV variants. [ABSTRACT FROM AUTHOR]

Streptococcus thermophilus is a traditional starter for yogurt making. Here, an eps gene cluster encoded for exopolysaccharides (EPS) was identified in the genome of S. thermophilus CGMCC 7.179. After purifying by DEAE-Sepharose Fast-Flow column chromatography, three main components ST-ESP1, ST-EPS2 and ST-EPS3, consisted of mannose, glucuronic acid, galacturonic acid, glucose and N-acetylglucosamine, were obtained. ST-EPS2 showed stronger antioxidant activity than the others in vitro. Moreover, ST-EPS2 could significantly upregulate the transcription levels of NF-E2-related factor-2 (Nrf2) and promote the expression of antioxidant-related proteins involved in Nrf2, suggesting ST-EPS2 protected the intestinal epithelial NCM 460 cells by attenuating the intracellular reactive oxygen species (ROS) level rising against oxidative stress. The potential binding mode of the mannose, galacturonic acid and N-acetylglucosamine with Keap1 simulated through molecular docking confirmed the action of ST-EPS2 with the protein Nrf2. Those results demonstrated that the ST-EPS2 provided opportunities for a natural antioxidant agent exploration in the food industry. • Three main components ST-ESP1, ST-EPS2, and ST-EPS3 were obtained by purification. • The preliminary structural features of three EPS components were determined. • ST-EPS2 protected the NCM 460 cells by attenuating the intracellular ROS content. • The binding of three monosaccharides to Keap1 was simulated by molecular docking. [ABSTRACT FROM AUTHOR]

It was reported that oral administration of Bacillus favored the growth of Lactobacillus in the intestinal tract. Here, this phenomenon was confirmed by co-cultivation of Bacillus subtilis 168 and Lactobacillus plantarum SDMCC050204-pL157 in vitro. To explain the possible molecular mechanisms, B. subtilis 168 cells were incubated in simulated intestinal fluid at 37 °C for 24 h, and up to 90% of cells autolysed in the presence of bile salts. Addition of the autolysate to medium inoculated with Lb. plantarum SDMCC050204 decreased the concentration of H2O2 in the culture, alleviated DNA damage and increased the survival of Lb. plantarum, as like the results of exogenous heme addition. These results suggested that the autolysate provided heme, which activated the heme-dependent catalase KatA in Lb. plantarum SDMCC050204. HPLC confirmed the presence of heme in the autolysate. Disruption of the Lb. plantarum SDMCC050204 katA gene abolished the protective effect of the B. subtilis 168 autolysate against H2O2 stress. We thus hypothesized that the beneficial effect of Bacillus toward Lactobacillus was established through activation of the heme-dependent catalase and remission of the damage of reactive oxygen species against Lactobacillus. This study raised new crosstalk between the two frequently-used probiotics, highlighting heme-dependent catalase as the key mediator. [ABSTRACT FROM AUTHOR]