Summary
RNA transport and localization represent important post‐transcriptional mechanisms to determine the subcellular localization of protein synthesis. Plants have the capacity to transport ...messenger (m)RNA molecules beyond the cell boundaries through plasmodesmata and over long distances in the phloem. RNA viruses exploit these transport pathways to disseminate their infections and represent important model systems to investigate RNA transport in plants. Here, we present an in vivo plant RNA‐labeling system based on the Escherichia coli RNA‐binding protein BglG. Using the detection of RNA in mobile RNA particles formed by viral movement protein (MP) as a model, we demonstrate the efficiency and specificity of mRNA detection by the BglG system as compared with MS2 and λN systems. Our observations show that MP mRNA is specifically associated with MP in mobile MP particles but hardly with MP localized at plasmodesmata. MP mRNA is clearly absent from MP accumulating along microtubules. We show that the in vivo BglG labeling of the MP particles depends on the presence of the BglG‐binding stem–loop aptamers within the MP mRNA and that the aptamers enhance the coprecipitation of BglG by MP, thus demonstrating the presence of an MP:MP mRNA complex. The BglG system also allowed us to monitor the cell‐to‐cell transport of the MP mRNA, thus linking the observation of mobile MP mRNA granules with intercellular MP mRNA transport. Given its specificity demonstrated here, the BglG system may be widely applicable for studying mRNA transport and localization in plants.
Significance Statement
Increasing evidence indicates the ability of plants to move RNA species between cells and tissues. Studies to understand the mechanisms by which RNA molecules are transported depend on suitable methods by which the fate of RNA molecules can be addressed in vivo. By adapting components of the bgl operon in Escherichia coli, we achieved unprecedented resolution in localizing the tobacco mosaic virus Movement Protein mRNA and tracking its cell‐to‐cell movement in vivo.
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•Green synthesis of Ag nanoparticles in a one-step using leaf extract of Kalanchoe Daigremontiana was performed.•Formation of Ag nanoflowers with different solvents was obtained.•Ag ...nanoflowers showed a high photocatalytic activity in the removal of methylene blue.•Ag nanoflowers showed high antibacterial activity against Escherichia coli, and Staphylococcus aureus bacteria.
The synthesis and applications of anisotropic nanostructures have attracted much attention in the last decade. The nanoflower-type structures are one of the nanomaterials with anisotropic structures most investigated because of owing to high densities of edges, corners, and stepped atoms present on their nano-petals. Here, silver nanoparticles obtained by a one-step green synthesis method using extract from Kalanchoe Daigremontiana´s leaves are reported. To identify the compounds responsible for reduction of silver ions, the functional groups present in plant extract were investigated by UV–vis and FTIR. Ag nanoparticles were characterized by UV–vis, XPS, ζ-potential, XRD, and SEM-EDS. Different solvents were used to eliminate agglomeration of the silver nanoparticles. These solvents produced nanoflower-like morphology with abundant nano-petals. This is the first report of the synthesis of Ag nanoflowers formed by green synthesis method using Kalanchoe Daigremontiana extract. The synthesized Ag nanoflowers are faced center cubic structure in nature with a petal thickness approximately of 25 nm. Photocatalytic activity of the different Ag nanostructures was evaluated through the degradation of methylene blue, where the degradation time as low as 1 min is reported. Furthermore these green synthesized Ag nanoflowers were found to show high antibacterial activity against Gram-negative bacteria Escherichia coli and Gram-positive Staphylococcus aureus.
Boron dipyrromethene (BODIPY) derivatives 1 and 2 consisting of donor and acceptor units with dual photoresponses to solvent polarity and luminogen aggregation are developed through taking advantage ...of twisted intramolecular charge transfer (TICT) and aggregation-induced emission (AIE) processes. In nonpolar solvents, the locally excited (LE) states of the BODIPY luminogens emit intense green lights. Increasing solvent polarity brings the luminogens from the LE state to the TICT state, causing a large bathochromic shift in the emission color but a dramatic decrease in the emission efficiency. The red emission is greatly boosted by aggregate formation or AIE effect: addition of large amounts of water into the solutions of 1 and 2 in the polar solvents causes the luminogens to aggregate supramolecularly and to emit efficiently. The emission can be enhanced by increasing solvent viscosity and decreasing solution temperature, indicating that the AIE effect is caused by the restriction of the intramolecular rotations in the aggregates of the luminogens.
Viscosity in the intracellular microenvironment shows a significant difference in various organelles and is closely related to cellular processes. Such microviscosity in live cells is often mapped ...and quantified with fluorescent molecular rotors. To enable the rational design of viscosity-sensitive molecular rotors, it is critical to understand their working mechanisms. Herein, we systematically synthesized and investigated two sets of BODIPY-based molecular rotors to study the relationship between intramolecular motions and viscosity sensitivity. Through experimental and computational studies, two conformations (i.e., the planar and butterfly conformations) are found to commonly exist in BODIPY rotors. We demonstrate that the transformation energy barrier from the planar conformation to the butterfly conformation is strongly affected by the molecular structures of BODIPY rotors and plays a critical role in viscosity sensitivity. These findings enable rational structure modifications of BODIPY molecular rotors for highly effective protein detection and recognition.
Polyenals and polyenones are simple chemical compounds which can be constructed into large and complex structures by virtue of aminocatalysis. In the past eight years, new aminocatalytic activation ...modes based on trienamine, cross‐trienamine, tetraenamine, iminium ion, and vinylogous iminium ion intermediates have attracted great attention in the field of asymmetric synthesis. Key to the increasing focus is their inherent ability to allow functionalization of remote sites with excellent stereoselectivities. Moreover, methodologies involving one‐pot, cascade or multicomponent strategies have been developed through the combination of these new activation modes with classical activation modes. In the course of expanding the applicability of organocatalysis, polyenals and polyenones have been introduced as simple and novel substrates, which have enabled the discovery of new concepts for the synthesis of many diverse and complex privileged structures.
Polyenals and polyenones are simple chemical compounds which can be constructed into large and complex structures by virtue of aminocatalysis. New methodologies involving aminocatalytic activation modes based on trienamine, cross‐trienamine, tetraenamine, iminium ion, and vinylogous iminium ion intermediates, which are leading to the synthesis of many diverse and complex privileged structures are discussed in this minireview.
A series of new symmetrical highly substituted BODIPYs 6 a–l was synthesized through a prefunctionalization approach in 35 %–89 % yields from the pyrrole core. This strategy allowed modulation of the ...substituents at the different positions based on the choice of Fischer's alkynyl carbenes, oxazolones and aldehydes used as precursors. The substituent variation at positions 2, 6, 3 and 5 had the greatest effect on the modulation of their photophysical properties such as absorption (λabs) and emission (λem) wavelengths, extinction coefficient (ϵ), quantum yields (ϕ), Stokes shifts (Δν), fluorescence decay, radiative (krad) and non‐radiative (knr) constants and the CIE 1931 coordinates. Theoretical calculations allowed to corroborate the effect of the substituents of meso‐position on the modification of the dihedral angles. Cyclic voltammetry studies revealed that the BODIPY series presents similar redox potential behavior, being electrochemically active even in successive cycles, which suggests that transport by diffusion is the dominant process.
Pyrrole polyfunctionalized core is obtained from Fischer alkynyl carbenes and oxazolones and used to obtain highly functionalized symmetric BODIPYs with modulating optoelectronic properties.
A series of BODIPY derivatives with tetraphenylethene (TPE) moieties were designed and synthesized. The effect of positions and numbers of substitution groups on the fluorescence of the BODIPYs was ...investigated. Theoretical calculation and single crystal structures proved that the TPE substitution groups on the 8-position of BODIPY contributed little to the conjugation, but benefited the aggregated state emission. On the other hand, the substitutions on the 3- or 5-position of BODIPY through vinyl bridges increased the conjugation length, and generated big coplanar π-conjugated structures with poor aggregated state emission. The compound with bright aggregated state emission has been further fabricated into biocompatible fluorescent nanoparticles and used as effective fluorescent contrast agents for intracellular imaging.
Examining why human populations used specific technologies in the Final Pleistocene is critical to understanding our evolutionary path. A key Final Pleistocene techno-tradition is the Howiesons ...Poort, which is marked by an increase in behavioral complexity and technological innovation. Central to this techno-tradition is the production of backed artifacts-small, sharp blades likely used as insets in composite tools. Although backed artifacts were manufactured for thousands of years before the Howiesons Poort, this period is marked by a phenomenal increase in their production. In this paper we test both social and environmental hypotheses to explain this phenomenon. We correlate environmental data with changing frequencies of backed artifact production at Sibudu and assess morphological similarity across seven sites in southern Africa. We find that these artifacts are made to a similar template across different regions and that their increased production correlates with multiple paleo-environmental proxies. When compared to an Australian outgroup, the backed artifacts from the seven southern African sites cluster within the larger shape space described by the Australian group. This leads us to argue that the observed standardized across southern Africa is related to cultural similarities and marks a strengthening of long-distance social ties during the MIS4.
The current energy crisis, in addition to the severe drought our planet is suffering, had led to the search for new alternatives to obtain green and sustainable fuel sources. Green hydrogen as an ...energy vector is one of the most promising possibilities. In this context, emerging technologies, such as photocatalysis, that can be driven by solar light, become especially challenging when using natural seawater (NSW) directly, avoiding previous purification steps. The exploitation of this endless resource is key to tackle the climate and energy emergency, although it faces questions derived from the presence of dissolved salts at significant concentrations. So far, some reports attribute to the latter the catalyst deactivation and loss of performance, whereas other authors have compared the results obtained with NSW and synthetic seawater and have reported higher rates of hydrogen generation with NSW. To solve this controversy, further research is needed to assess both the viability of the photocatalytic hydrogen generation from NSW and the conditions for the optimum process performance. Within this context, this study has evaluated two easy to purchase photocatalysts, TiO2 as benchmark, and CdS, in a concentration range from 50 to 150 mg L−1. Different sacrificial agents are used depending on the catalyst, 20% CH3OH for TiO2 and 0–0.1 mol L−1 Na2S/Na2SO3 range for CdS. The experiments performed in batch mode gave promising results and shed new light on the positive influence of the buffer capacity of NSW, providing information about the mechanisms that take place during the process. Furthermore, this study fosters the advancement of hydrogen production technologies based on abundant and inexpensive raw materials.
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•Experimental analysis of photocatalytic hydrogen generation from seawater.•CdS and Na2S/Na2SO3 have been used in the experiments.•Results with model seawater, SSW, and natural seawater, NSW, are compared.•NSW positively influenced hydrogen production due to its buffer capacity.
Fully unsubstituted 4,4-difluoro-4-bora-3a,4a-diaza-s-indacene (BODIPY) 1 was prepared. Reaction of 8-thiomethylbodipy 2 with triethylsilane in the presence of a catalytic amount of Pd and a ...stoichiometric amount of copper(I) thienyl-2-carboxylate (CuTC) in THF at 55 °C gave compound 1 in nearly quantitative yield. This compound displays high quantum yields (up to 93%) in polar solvents including water. Its optical properties and crystal structure are discussed.
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