Search results for "CB"
showing 10 items of 647 documents
Current Spreading Length and Injection Efficiency in ZnO/GaN-Based Light-Emitting Diodes
2019
We report on carrier injection features in light-emitting diodes (LEDs) based on nonintentionally doped-ZnO/p-GaN heterostructures. These LEDs consist of a ZnO layer grown by chemical-bath deposition (CBD) onto a p-GaN template without using any seed layer. The ZnO layer (~1- $\mu \text{m}$ thickness) consists of a dense collection of partially coalesced ZnO nanorods, organized in wurtzite phase with marked vertical orientation, whose density depends on the concentration of the solution during the CBD process. Due to the limited conductivity of the p-GaN layer, the recombination in the n-region is strongly dependent on the spreading length of the holes, ${L}_{h}$ , coming from the p-contact…
Thioredoxin (Trxo1) interacts with proliferating cell nuclear antigen (PCNA) and its overexpression affects the growth of tobacco cell culture.
2017
Thioredoxins (Trxs), key components of cellular redox regulation, act by controlling the redox status of many target proteins, and have been shown to play an essential role in cell survival and growth. The presence of a Trx system in the nucleus has received little attention in plants, and the nuclear targets of plant Trxs have not been conclusively identified. Thus, very little is known about the function of Trxs in this cellular compartment. Previously, we studied the intracellular localization of PsTrxo1 and confirmed its presence in mitochondria and, interestingly, in the nucleus under standard growth conditions. In investigating the nuclear function of PsTrxo1 we identified proliferati…
Reaction norms of host immunity, host fitness and parasite performance in a mouse - intestinal nematode interaction.
2016
8 pages; International audience; The outcome of the encounter between a host and a parasite depends on the synergistic effects of the genetics of the two partners and the environment (sensulato) where the interaction takes place. Reaction norms can depict how host and parasite traits vary across environmental ranges for different genotypes. Here, we performed a large scale experiment where three strains of laboratory mice (SJL, BALB/c and CBA) were infected with four doses of the intestinal nematode Heligmosomoides polygyrus. An increasing infective dose can be considered as a proxy for the environment-dependent risk incontracting the infection. We looked at the fitness traits of hosts and …
Innovative, ecofriendly biosorbent-biodegrading biofilms for bioremediation of oil- contaminated water.
2019
Immobilization of microorganisms capable of degrading specific contaminants significantly promotes bioremediation processes. In this study, innovative and ecofriendly biosorbent-biodegrading biofilms have been developed in order to remediate oil-contaminated water. This was achieved by immobilizing hydrocarbon-degrading gammaproteobacteria and actinobacteria on biodegradable oil-adsorbing carriers, based on polylactic acid and polycaprolactone electrospun membranes. High capacities for adhesion and proliferation of bacterial cells were observed by scanning electron microscopy. The bioremediation efficiency of the systems, tested on crude oil and quantified by gas chromatography, showed that…
Survey on the presence of non-dioxine-like PCBs (NDL-PCBs) in loggerhead turtles (Caretta caretta) stranded in south Mediterranean coasts (Sicily, So…
2017
A total of 71 loggerhead turtles (Caretta caretta) stranded along the coasts of Sicily (Southern Italy) were examined for non-dioxine like polychlorinated biphenyl (NDL-PCB) levels in muscle and adipose tissue by a gas chromatography-mass spectrometry/mass spectrometry (GC-MS/MS) method. The results revealed 6 high-indicator congener (∑6 PCBIND ) levels in 45% of the loggerhead turtles examined, with mean values of 980.39 ± 2508.39 ng/g wet weight in adipose tissue and 102.53 ± 238.58 ng/g wet weight in muscle tissue. The hexachloro and heptachloro PCB congeners were the most abundant in both the sample types. The highest NDL-PCB levels were reached in an adipose tissue sample of a loggerhe…
An early Ca2+ influx is a prerequisite to thaxtomin A-induced cell death in Arabidopsis thaliana cells
2008
International audience; The pathogenicity of various Streptomyces scabies isolates involved in potato scab disease was correlated with the production of thaxtomin A. Since calcium is known as an essential second messenger associated with pathogen-induced plant responses and cell death, it was investigated whether thaxtomin A could induce a Ca 2+ influx related to cell death and to other putative plant responses using Arabidopsis thaliana suspension cells, which is a convenient model to study plant–microbe interactions. A. thaliana cells were treated with micromolar concentrations of thaxto-min A. Cell death was quantified and ion flux variations were analysed from electrophysiological measu…
Unravelling the determinants of freezing tolerance in Medicago truncatula: a first step towards improving the response of crop legumes to freezing st…
2020
International audience; Freezing is a major environmental limitation that affects biomass and seed productivity in a large number of crop species including legumes. Medicago truncatula is a model molecular‐genetic system for legume biology. A strategy to decipher freezing tolerance after a cold acclimation period in M. truncatula was developed using a quantitative genetic approach. Three main quantitative trait loci (QTL) with additive effects for freezing damage were detected on chromosomes 1, 4, and 6 using a recombinant inbred line population derived from a cross between the freezing‐tolerant accession F83005‐5 and the freezing‐sensitive accession DZA045‐5. The QTL on chromosome 6, named…
Betulinic Acid Exerts Cytotoxic Activity Against Multidrug-Resistant Tumor Cells via Targeting Autocrine Motility Factor Receptor (AMFR).
2018
Betulinic acid (BetA) is a naturally occurring pentacyclic triterpene isolated from the outer bark of white-barked birch trees and many other medicinal plants. Here, we studied betulinic acid's cytotoxic activity against drug-resistant tumor cell lines. P-glycoprotein (MDR1/ABCB1) and BCRP (ABCG2) are known ATP-binding cassette (ABC) drug transporters that mediating MDR. ABCB5 is a close relative to ABCB1, which also mediates MDR. Constitutive activation of the EGF receptor is tightly linked to the development of chemotherapeutic resistance. BetA inhibited P-gp, BCRP, ABCB5 and mutation activated EGFR overexpressing cells with similar efficacy as their drug-sensitive parental counterparts. …
Cytotoxicity of sesquiterpene alkaloids from Nuphar plants toward sensitive and drug-resistant cell lines.
2018
Multi-drug resistance (MDR) is a critical problem in cancer chemotherapy. MDR causes the overexpression of ATP-binding cassette (ABC) transporters and mutations in tumor suppressor genes and oncogenes. To tackle this issue, in this study, we focused on Nuphar plants, which have been traditionally used as food. Sesquiterpene alkaloids (1–3) were isolated from N. japonicum and dimeric sesquiterpene thioalkaloids (4–10) were isolated from N. pumilum. P-glycoprotein-overexpressing CEM/ADR5000 cells were cross-resistant to 6,6′-dihydroxythiobinupharidine (10). Using in silico molecular docking, we calculated the binding energies and simulated the interactions of these compounds with the correspo…
Molecular Determinants of Sensitivity or Resistance of Cancer Cells Toward Sanguinarine.
2018
For decades, natural products represented a significant source of diverse and unique bioactive lead compounds in drug discovery field. In Clinical oncology, complete tumors remission is hampered by the development of drug-resistance. Therefore, development of cytotoxic agents that may overcome drug resistance is urgently needed. Here, the natural benzophenanthridine alkaloid sanguinarine has been studied for its cytotoxic activity against multidrug resistance (MDR) cancer cells. We investigated the role of the ATP-binding cassette (ABC) transporters BCRP/ABCG2, P-glycoprotein/ABCB1 and its close relative ABCB5 in drug resistance. Further drug resistance mechanisms analyzed in this study wer…