Identification of a male-specific amplified fragment length polymorphism (AFLP) marker in Broussonetia papyrifera

The present study exhibits amplified fragment length polymorphism (AFLP) molecular marker for sex identification in Broussonetia papyrifera. Based on nine selective amplification primer combinations, 230 bands were produced and the E-AGG/M-CAA combination was found to be a male-specific AFLP marker. Subsequently, this male-specific AFLP fragment was sequenced and converted into a sequence tagged site (STS) marker. Based on STS sequence, two primers, MADB-1 and MADB-2 (Male-Associated DNA from B. papyrifera), were designed to verify the specificity of the fragment. The results indicate that common homology sequence is existed in both male and female plants while one of the bands amplified via MADB-2 primer was solely present in male individuals at high annealing temperature up to 66°C. Finally, MADB-2 primer was introduced to amplify another 16 plants and it revealed that this primer could be used as a convenient, efficient, reliable, and low-cost molecular marker for sex identification in B. papyrifera.Keywords: Broussonetia papyrifera, AFLP, STS, male-specific marke

Oxidation of alkyl benzenes by a flavin photooxidation catalyst on nanostructured metal-oxide films

There are significant advantages in organic, interfacial photooxidation catalysis. Surface-bound catalysts on oxide interfaces offer highly reactive assemblies that minimize both catalyst and solution volume. We demonstrate here the oxygenation of alkyl benzenes by a flavin mononucleotide on nanoporous ZrO2 or TiO2 surfaces

Light-responsive expression atlas reveals the effects of light quality and intensity in Kalanchoë fedtschenkoi, a plant with crassulacean acid metabolism.

BackgroundCrassulacean acid metabolism (CAM), a specialized mode of photosynthesis, enables plant adaptation to water-limited environments and improves photosynthetic efficiency via an inorganic carbon-concentrating mechanism. Kalanchoë fedtschenkoi is an obligate CAM model featuring a relatively small genome and easy stable transformation. However, the molecular responses to light quality and intensity in CAM plants remain understudied.ResultsHere we present a genome-wide expression atlas of K. fedtschenkoi plants grown under 12 h/12 h photoperiod with different light quality (blue, red, far-red, white light) and intensity (0, 150, 440, and 1,000 μmol m-2 s-1) based on RNA sequencing performed for mature leaf samples collected at dawn (2 h before the light period) and dusk (2 h before the dark period). An eFP web browser was created for easy access of the gene expression data. Based on the expression atlas, we constructed a light-responsive co-expression network to reveal the potential regulatory relationships in K. fedtschenkoi. Measurements of leaf titratable acidity, soluble sugar, and starch turnover provided metabolic indicators of the magnitude of CAM under the different light treatments and were used to provide biological context for the expression dataset. Furthermore, CAM-related subnetworks were highlighted to showcase genes relevant to CAM pathway, circadian clock, and stomatal movement. In comparison with white light, monochrome blue/red/far-red light treatments repressed the expression of several CAM-related genes at dusk, along with a major reduction in acid accumulation. Increasing light intensity from an intermediate level (440 μmol m-2 s-1) of white light to a high light treatment (1,000 μmol m-2 s-1) increased expression of several genes involved in dark CO2 fixation and malate transport at dawn, along with an increase in organic acid accumulation.ConclusionsThis study provides a useful genomics resource for investigating the molecular mechanism underlying the light regulation of physiology and metabolism in CAM plants. Our results support the hypothesis that both light intensity and light quality can modulate the CAM pathway through regulation of CAM-related genes in K. fedtschenkoi

Plasmon-enhanced light-driven water oxidation by a dye-sensitized photoanode

Dye-sensitized photoelectrosynthesis cells (DSPECs) provide a basis for artificial photosynthesis and solar fuels production. By combining molecular chromophores and catalysts with high surface area, transparent semiconductor electrodes, a DSPEC provides the basis for light-driven conversion of water to O2 and H2 or for reduction of CO2 to carbon-based fuels. The incorporation of plasmonic cubic silver nanoparticles, with a strongly localized surface plasmon absorbance near 450 nm, to a DSPEC photoanode induces a great increase in the efficiency of water oxidation to O2 at a DSPEC photoanode. The improvement in performance by the molecular components in the photoanode highlights a remarkable advantage for the plasmonic effect in driving the 4e-/4H+ oxidation of water to O2 in the photoanode

A donor-chromophore-catalyst assembly for solar CO2 reduction

We describe here the preparation and characterization of a photocathode assembly for CO2 reduction to CO in 0.1 M LiClO4 acetonitrile. The assembly was formed on 1.0 μm thick mesoporous films of NiO using a layer-by-layer procedure based on Zr(IV)–phosphonate bridging units. The structure of the Zr(IV) bridged assembly, abbreviated as NiO|-DA-RuCP22+-Re(I), where DA is the dianiline-based electron donor (N,N,N′,N′-((CH2)3PO3H2)4-4,4′-dianiline), RuCP2+ is the light absorber [Ru((4,4′-(PO3H2CH2)2-2,2′-bipyridine)(2,2′-bipyridine))2]2+, and Re(I) is the CO2 reduction catalyst, ReI((4,4′-PO3H2CH2)2-2,2′-bipyridine)(CO)3Cl. Visible light excitation of the assembly in CO2 saturated solution resulted in CO2 reduction to CO. A steady-state photocurrent density of 65 μA cm−2 was achieved under one sun illumination and an IPCE value of 1.9% was obtained with 450 nm illumination. The importance of the DA aniline donor in the assembly as an initial site for reduction of the RuCP2+ excited state was demonstrated by an 8 times higher photocurrent generated with DA present in the surface film compared to a control without DA. Nanosecond transient absorption measurements showed that the expected reduced one-electron intermediate, RuCP+, was formed on a sub-nanosecond time scale with back electron transfer to the electrode on the microsecond timescale which competes with forward electron transfer to the Re(I) catalyst at t1/2 = 2.6 μs (kET = 2.7 × 105 s−1)

Aqueous multivariate phototransformation kinetics of dissociated tetracycline:implications for the photochemical fate in surface waters

Antibiotics are ubiquitous pollutants in aquatic systems and can exist as different dissociated species depending on the water pH. New knowledge of their multivariate photochemical behavior (i.e., the photobehavior of different ionized forms) is needed to improve our understanding on the fate and possible remediation of these pharmaceuticals in surface and waste waters. In this study, the photochemical degradation of aqueous tetracycline (TC) and its dissociated forms (TCH20, TCH−, and TC2−) was investigated. Simulated sunlight experiments and matrix calculations indicated that the three dissociated species had dissimilar photolytic kinetics and photooxidation reactivities. TC2− photodegraded the fastest due to apparent photolysis with a kinetic constant of 0.938 ± 0.021 min−1, followed by TCH− (0.020 ± 0.005 min−1) and TCH20 (0.012 ± 0.001 min−1), whereas TCH− was found to be the most highly reactive toward •OH (105.78 ± 3.40 M−1s−1), and TC2− reacted the fastest with 1O2 (344.96 ± 45.07 M−1 s−1). Water with relatively high pH (e.g., ~ 8–9) favors the dissociated forms of TCH− and TC2− which are most susceptible to photochemical loss processes compared to neutral TC. The calculated corresponding environmental half-lives (t1/2,E) in sunlit surface waters ranged from 0.05 h for pH = 9 in midsummer to 3.68 h for pH = 6 in midwinter at 45° N latitude. The process was dominated by apparent photolysis (especially in summer, 62–91%), followed by 1O2 and •OH oxidation. Adjusting the pH to slightly alkaline conditions prior to UVor solar UV light treatment may be an effective way of enhancing the photochemical removal of TC from contaminated water

Three years of wastewater surveillance for new psychoactive substances from 16 countries

The proliferation of new psychoactive substances (NPS) over recent years has made their surveillance complex. The analysis of raw municipal influent wastewater can allow a broader insight into community consumption patterns of NPS. This study examines data from an international wastewater surveillance program that collected and analysed influent wastewater samples from up to 47 sites in 16 countries between 2019 and 2022. Influent wastewater samples were collected over the New Year period and analysed using validated liquid chromatography - mass spectrometry methods. Over the three years, a total of 18 NPS were found in at least one site. Synthetic cathinones were the most found class followed by phenethylamines and designer benzodiazepines. Furthermore, two ketamine analogues, one plant based NPS (mitragynine) and methiopropamine were also quantified across the three years. This work demonstrates that NPS are used across different continents and countries with the use of some more evident in particular regions. For example, mitragynine has highest mass loads in sites in the United States, while eutylone and 3-methylmethcathinone increased considerably in New Zealand and in several European countries, respectively. Moreover, 2F-deschloroketamine, an analogue of ketamine, has emerged more recently and could be quantified in several sites, including one in China, where it is considered as one of the drugs of most concern. Finally, some NPS were detected in specific regions during the initial sampling campaigns and spread to additional sites by the third campaign. Hence, wastewater surveillance can provide an insight into temporal and spatial trends of NPS use

Ultrathin TiO₂ Blocking Layers via Atomic Layer Deposition toward High-Performance Dye-Sensitized Photo-Electrosynthesis Cells

The collection of solar energy in chemical bonds via dye-sensitized photoelectrosynthesis cells (DSPECs) is a reliable solution. Herein, atomic layer deposition (ALD) introduced ultrathin blocking layers (BLs) between a mesoporous TiO2 membrane and fluorine-doped tin oxide (FTO), and much improved photoelectrochemical water oxidation performance was well documented. Samples with different BL thicknesses deposited on FTO were obtained by ALD. In the photoanode, polypyridyl Ru(II) complexes were used as photosensitizers, and Ru(bda)-type was used as a catalyst during water oxidation. Under one sun irradiation, the BL (i) increased the photocurrent density; (ii) slowed down the open-circuit voltage decay (OCVD) by electrochemical measurement; (iii) increased the photo-generated electron lifetime roughly from 1 s to more than 100 s; and (iv) enhanced the water oxidation efficiency from 25% to 85% with 0.4 V of applied voltage bias. All this pointed out that the ALD technique-prepared layers could greatly hinder the photogenerated electron–hole pair recombination in the TiO2-based photoanode. This study offers critical backing for the building of molecular films by the ALD technique to split water effectively

Simulating Molecular Interactions of Carbon Nanoparticles with a Double-Stranded DNA Fragment

Molecular interactions between carbon nanoparticles (CNPs) and a double-stranded deoxyribonucleic acid (dsDNA) fragment were investigated using molecular dynamics (MD) simulations. Six types of CNPs including fullerenes (C60 and C70), (8,0) single-walled carbon nanotube (SWNT), (8,0) double-walled carbon nanotube (DWNT), graphene quantum dot (GQD), and graphene oxide quantum dot (GOQD) were studied. Analysis of the best geometry indicates that the dsDNA fragment can bind to CNPs through pi-stacking and T-shape. Moreover, C60, DWNT, and GOQD bind to the dsDNA molecules at the minor groove of the nucleotide, and C70, SWNT, and GQD bind to the dsDNA molecules at the hydrophobic ends. Estimated interaction energy implies that van der Waals force may mainly contribute to the mechanisms for the dsDNA-C60, dsDNA-C70, and dsDNA-SWNT interactions and electrostatic force may contribute considerably to the dsDNA-DWNT, dsDNA-GQD, and dsDNA-GOQD interactions. On the basis of the results from large-scale MD simulations, it was found that the presence of the dsDNA enhances the dispersion of C60, C70, and SWNT in water and has a slight impact on DWNT, GQD, and GOQD

Combined Toxicity of TiO2 Nanospherical Particles and TiO2 Nanotubes to Two Microalgae with Different Morphology

The joint activity of multiple engineered nanoparticles (ENPs) has attracted much attention in recent years. Many previous studies have focused on the combined toxicity of different ENPs with nanostructures of the same dimension. However, the mixture toxicity of multiple ENPs with different dimensions is much less understood. Herein, we investigated the toxicity of the binary mixture of TiO2 nanospherical particles (NPs) and TiO2 nanotubes (NTs) to two freshwater algae with different morphology, namely, Scenedesmus obliquus and Chlorella pyrenoidosa. The physicochemical properties, dispersion stability, and the generation of reactive oxygen species (ROS) were determined in the single and binary systems. Classical approaches to assessing mixture toxicity were applied to evaluate and predict the toxicity of the binary mixtures. The results show that the combined toxicity of TiO2 NPs and NTs to S. obliquus was between the single toxicity of TiO2 NTs and NPs, while the combined toxicity to C. pyrenoidosa was higher than their single toxicity. Moreover, the toxicity of the binary mixtures to C. pyrenoidosa was higher than that to S. obliquus. A toxic unit assessment showed that the effects of TiO2 NPs and NTs were additive to the algae. The combined toxicity to S. obliquus and C. pyrenoidosa can be effectively predicted by the concentration addition model and the independent action model, respectively. The mechanism of the toxicity caused by the binary mixtures of TiO2 NPs and NTs may be associated with the dispersion stability of the nanoparticles in aquatic media and the ROS-induced oxidative stress effects. Our results may offer a new insight into evaluating and predicting the combined toxicological effects of ENPs with different dimensions and of probing the mechanisms involved in their joint toxicity