WHIRLIES are plant-specific proteins binding to DNA in plastids, mitochondria, and nucleus. They have been identified as significant components of nucleoids in the organelles where they regulate the ...structure of the nucleoids and diverse DNA-associated processes. WHIRLIES also fulfil roles in the nucleus by interacting with telomers and various transcription factors, among them members of the WRKY family. While most plants have two WHIRLY proteins, additional WHIRLY proteins evolved by gene duplication in some dicot families. All WHIRLY proteins share a conserved WHIRLY domain responsible for ssDNA binding. Structural analyses revealed that WHIRLY proteins form tetramers and higher-order complexes upon binding to DNA. An outstanding feature is the parallel localization of WHIRLY proteins in two or three cell compartments. Because they translocate from organelles to the nucleus, WHIRLY proteins are excellent candidates for transducing signals between organelles and nucleus to allow for coordinated activities of the different genomes. Developmental cues and environmental factors control the expression of WHIRLY genes. Mutants and plants with a reduced abundance of WHIRLY proteins gave insight into their multiple functionalities. In chloroplasts, a reduction of the WHIRLY level leads to changes in replication, transcription, RNA processing, and DNA repair. Furthermore, chloroplast development, ribosome formation, and photosynthesis are impaired in monocots. In mitochondria, a low level of WHIRLIES coincides with a reduced number of cristae and a low rate of respiration. The WHIRLY proteins are involved in the plants' resistance toward abiotic and biotic stress. Plants with low levels of WHIRLIES show reduced responsiveness toward diverse environmental factors, such as light and drought. Consequently, because such plants are impaired in acclimation, they accumulate reactive oxygen species under stress conditions. In contrast, several plant species overexpressing WHIRLIES were shown to have a higher resistance toward stress and pathogen attacks. By their multiple interactions with organelle proteins and nuclear transcription factors maybe a comma can be inserted here? and their participation in organelle-nucleus communication, WHIRLY proteins are proposed to serve plant development and stress resistance by coordinating processes at different levels. It is proposed that the multifunctionality of WHIRLY proteins is linked to the plasticity of land plants that develop and function in a continuously changing environment.
SUMMARY
WHIRLY1 is a chloroplast‐nucleus located DNA/RNA‐binding protein with functions in development and stress tolerance. By overexpression of HvWHIRLY1 in barley, one line with a 10‐fold and two ...lines with a 50‐fold accumulation of the protein were obtained. In these lines, the relative abundance of the nuclear form exceeded that of the chloroplast form. Growth of the plants was shown to be compromised in a WHIRLY1 abundance‐dependent manner. Over‐accumulation of WHIRLY1 in chloroplasts had neither an evident impact on nucleoid morphology nor on the composition of the photosynthetic apparatus. Nevertheless, oeW1 plants were found to be compromised in the light reactions of photosynthesis as well as in carbon fixation. The reduction in growth and photosynthesis was shown to be accompanied by a decrease in the levels of cytokinins and an increase in the level of jasmonic acid. Gene expression analyses revealed that in nonstress conditions the oeW1 plants had enhanced levels of pathogen response (PR) gene expression indicating activation of constitutive defense. During growth in continuous light of high irradiance PR gene expression increased indicating that under stress conditions oeW1 are capable to further enhance defense.
Significance Statement
With regard to its dual localization in chloroplasts and nucleus WHIRLY1 is an excellent communicator in retrograde signaling. Previous studies with barley showed that a knockdown of WHIRLY1 compromises acclimation to environment. Here we show that overexpression of WHIRLY1 in barley, leading to an over‐accumulation of the protein in both chloroplasts and nucleus, improves stress resistance whereas it has a negative impact on photosynthesis and growth.
HvPAP14 is a cysteine protease found in association with thylakoid membranes. Among its putative substrates are proteins such as LHCB1, LHCB5, PSBO, and RbcL, as revealed in overexpressing barley ...plants.
Abstract
Chloroplast protein degradation is known to occur both inside chloroplasts and in the vacuole. Genes encoding cysteine proteases have been found to be highly expressed during leaf senescence. However, it remains unclear where they participate in chloroplast protein degradation. In this study HvPAP14, which belongs to the C1A family of cysteine proteases, was identified in senescing barley (Hordeum vulgare L.) leaves by affinity enrichment using the mechanism-based probe DCG-04 targeting cysteine proteases and subsequent mass spectrometry. Biochemical analyses and expression of a HvPAP14:RFP fusion construct in barley protoplasts was used to identify the subcellular localization and putative substrates of HvPAP14. The HvPAP14:RFP fusion protein was detected in the endoplasmic reticulum and in vesicular bodies. Immunological studies showed that HvPAP14 was mainly located in chloroplasts, where it was found in tight association with thylakoid membranes. The recombinant enzyme was activated by low pH, in accordance with the detection of HvPAP14 in the thylakoid lumen. Overexpression of HvPAP14 in barley revealed that the protease can cleave LHCB proteins and PSBO as well as the large subunit of Rubisco. HvPAP14 is involved in the normal turnover of chloroplast proteins and may have a function in bulk protein degradation during leaf senescence.
Chloroplast protein degradation was found to occur both inside chloroplasts and in the vacuole. Genes encoding cysteine proteases were found to be highly expressed during leaf senescence. It remained ...however unclear where they participate in chloroplast protein degradation. HvPAP14, belonging to the C1A family of cysteine proteases was identified in senescing barley (Hordeumvulgare L.) leaves by affinity enrichment using the mechanism-based probe DCG-04 targeting cysteine proteases and subsequent mass spectrometry. Biochemical analyses and expression of a HvPAP14:RFP fusion construct in barley protoplasts was employed to identify subcellular localization and putative substrates of HvPAP14. The HvPAP14:RFP fusion protein was detected in the endoplasmic reticulum and in vesicular bodies. Immunological studies showed HvPAP14 mainly located in chloroplasts, where it was found in tight association with thylakoid membranes. The recombinant enzyme is activated by low pH being in accordance with the detection of HvPAP14 in the thylakoid lumen. Overexpression of HvPAP14 in barley revealed that the protease can cleave LHCB proteins, PSBO as well as the large subunit of Rubisco. HvPAP14 is involved in normal turnover of chloroplast proteins and might have a function for bulk protein degradation during leaf senescence.
We report on the preparation of Li+ conducting lithium phosphorus oxynitride (LiPON) layers by ion beam sputtering, resulting in ultra-thin layers with a thickness down to only 12 nm. The morphology ...of the layers is studied by transmission electron microscopy, whereas homogeneity and excellent interface quality is observed. The ion conducting properties of the layers are studied as a function of temperature and layer thickness, using electrochemical impedance spectroscopy. In these measurements, a specific ionic conductivity at room temperature of around 2 · 10−7 S cm−1 is found that results in a maximum conductance of 0.2 S cm−2, thanks to their ultra-small thickness. To demonstrate the applicability of the thin films as functional solid state electrolyte, Ag/LiPON/Pt triple layers are studied, serving as models for all solid state batteries. The functionality of these model batteries is measured by cyclic voltammetry of up to 100 charge–discharge cycles, and their morphology after cycling is investigated by transmission electron microscopy. For the first time, these investigations give insight into the morphology of this kind of model cell after intensive cycling. In particular, they allow determining the specific lithium storage capacity of the interface reaction layer between Ag and LiPON, which is found to be around 12 μAh cm−2 μm−1.
•Ultra-thin LiPON layers (195 nm–12 nm) are prepared by ion beam sputtering.•Layers are characterized by impedance spectroscopy and electron microscopy.•LiPON layers are found to exhibit a surface roughness below 3 nm.•A functional all solid state battery of less than 1 μm in thickness is prepared.•The thin film battery after cycling is studied by transmission electron microscopy.
Reproducible research and open science practices have the potential to accelerate scientific progress by allowing others to reuse research outputs, and by promoting rigorous research that is more ...likely to yield trustworthy results. However, these practices are uncommon in many fields, so there is a clear need for training that helps and encourages researchers to integrate reproducible research and open science practices into their daily work. Here, we outline eleven strategies for making training in these practices the norm at research institutions. The strategies, which emerged from a virtual brainstorming event organized in collaboration with the German Reproducibility Network, are concentrated in three areas: (i) adapting research assessment criteria and program requirements; (ii) training; (iii) building communities. We provide a brief overview of each strategy, offer tips for implementation, and provide links to resources. We also highlight the importance of allocating resources and monitoring impact. Our goal is to encourage researchers - in their roles as scientists, supervisors, mentors, instructors, and members of curriculum, hiring or evaluation committees - to think creatively about the many ways they can promote reproducible research and open science practices in their institutions.
We present a fully reversible and highly efficient on–off photoswitching of magnetic resonance imaging (MRI) contrast with green (500 nm) and violet-blue (435 nm) light. The contrast change is based ...on intramolecular light-driven coordination-induced spin state switch (LD-CISSS), performed with azopyridine-substituted Ni-porphyrins. The relaxation time of the solvent protons in 3 mM solutions of the azoporphyrins in DMSO was switched between 3.5 and 1.7 s. The relaxivity of the contrast agent changes by a factor of 6.7. No fatigue or side reaction was observed, even after >100 000 switching cycles in air at room temperature. Electron-donating substituents at the pyridine improve the LD-CISSS in two ways: better photostationary states are achieved, and intramolecular binding is enhanced.
A common feature of domestic animals is tameness-i.e., they tolerate and are unafraid of human presence and handling. To gain insight into the genetic basis of tameness and aggression, we studied an ...intercross between two lines of rats (Rattus norvegicus) selected over >60 generations for increased tameness and increased aggression against humans, respectively. We measured 45 traits, including tameness and aggression, anxiety-related traits, organ weights, and levels of serum components in >700 rats from an intercross population. Using 201 genetic markers, we identified two significant quantitative trait loci (QTL) for tameness. These loci overlap with QTL for adrenal gland weight and for anxiety-related traits and are part of a five-locus epistatic network influencing tameness. An additional QTL influences the occurrence of white coat spots, but shows no significant effect on tameness. The loci described here are important starting points for finding the genes that cause tameness in these rats and potentially in domestic animals in general.
Hot-melt extrusion is gaining importance for the production of amorphous solid solutions; in parallel, predictive tools for estimating drug solubility in polymers are increasingly demanded. The ...Hansen solubility parameter (SP) approach is well acknowledged for its predictive power of the miscibility of liquids as well as the solubility of some amorphous solids in liquid solvents. By solely using the molecular structure, group contribution (GC) methods allow the calculation of Hansen SPs. The GC parameter sets available were derived from liquids and polymers which conflicts with the object of prediction, the solubility of solid drugs. The present study takes a step from the liquid based SPs toward their application to solid solutes. On the basis of published experimental Hansen SPs of solid drugs and excipients only, a new GC parameter set was developed. In comparison with established parameter sets by van Krevelen/Hoftyzer, Beerbower/Hansen, Breitkreutz and Stefanis/Panayiotou, the new GC parameter set provides the highest overall predictive power for solubility experiments (correlation coefficient r=−0.87 to −0.91) as well as for literature data on melt extrudates and casted films (r=−0.78 to −0.96).
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