Matthiesenhensley9444

Our previous study using transposon mutagenesis indicated that disruption of the putative response regulator gene orrA impacted antibiotic production in Streptomyces coelicolor. In this study, the role of OrrA was further characterized by comparing the phenotypes and transcriptomic profiles of the wild-type S. coelicolor strain M145 and ΔorrA, a strain with an inactivated orrA gene. Chromatin immunoprecipitation using a strain expressing OrrA fused with FLAG showed that OrrA binds the promoter of wblA, whose expression was downregulated in ΔorrA. The interaction of OrrA with the wblA promoter was further validated by a pull-down assay. Similar to ΔorrA, the deletion mutant of wblA (ΔwblA) was defective in development, and developmental genes were expressed at similar levels in ΔorrA and ΔwblA. Although both OrrA and WblA downregulated actinorhodin and undecylprodigiosin, their roles in regulation of the calcium-dependent antibiotic and yellow-pigmented type I polyketide differed. sco1375, a gene of unknown function, was identified as another OrrA target, and overexpression of either sco1375 or wblA in ΔorrA partially restored the wild-type phenotype, indicating that these genes mediate some of the effects of OrrA. This study revealed targets of OrrA and provided more insights into the role of the orphan response regulator OrrA in Streptomyces.A 2-biphenylacetylene was fixed into a specific conformation within the confined cavity of a hollow cage, where it underwent a regioselective spirocyclization in the presence of an electrophile. A 5-endo-dig cyclization proceeded selectively in the cage, which stands in sharp contrast to the 6-endo-dig cyclization that normally occurs in common organic media. The folded conformation adopted by the substrate within the cage was examined by 1 H NMR spectroscopy and X-ray crystallographic analysis.Molten chlorides are proposed for fast-spectrum molten salt reactors. Molten MgCl2 with NaCl forms eutectic mixtures and is considered as a promising dilutant to dissolve fuel salts such as UCl3 and UCl4 . A previous study suggests the formation of a U-Cl network at the U  Na=1  1 binary salt. However, it is unclear how the structure of UCln (n=3, 4) in NaCl will change after adding MgCl2 in the salt. Here, we use first-principles molecular dynamics to investigate the molten ternary salts NaCl-MgCl2 -UCln (n=3, 4) at various concentrations of Mg2+ in NaCl-UCln with a fixed ratio of Na  U at 1  1. It is found that the addition of Mg2+ to NaCl-UCl3 leads to a higher coordination number (from 6.5 to 6.7) of Cl around U while the U-Cl network structure slightly decreases with the Mg concentration. Adding MgCl2 to NaCl-UCl4 , however, breaks down the U-Cl network more completely. We attribute the different behavior of adding Mg2+ into NaCl-UCl3 and NaCl-UCl4 to the difference between U(III) and U(IV) in attracting Cl- ions to form the first coordination shell. The present work reveals the impact of MgCl2 as a dilutant solvent for NaCl-UCln fuel salts, which will be helpful in further studies and understanding of the thermophysical and transport properties of ternary systems.Tetraarylmethanes and adamantanes are important rigid covalent connectors that play a four-way scaffolding role in molecular and materials chemistry. We report the synthesis of a new tetravalent phosphaza-adamantane cage, (PNSiMe3 )4 (NMe)6 (2), that shows high thermal, air, and redox stability due to its geometry. It nevertheless participates in covalent four-fold functionalization reactions along its periphery. The combination of a robust core and reactive corona makes 2 a convenient inorganic scaffold upon which tetrahedral molecular and macromolecular chemistry can be constructed. This potential is demonstrated by the synthesis of a tetrakis(bis(phosphine)iminium) ion (in compound 3) and the first all P/N poly(phosphazene) network (5).Climate change may affect plant-herbivore interactions and their associated ecosystem functions. In an experimental evolution approach, we subjected replicated populations of the invasive Ambrosia artemisiifolia to a combination of simulated warming and herbivory by a potential biocontrol beetle. We tracked genomic and metabolomic changes across generations in field populations and assessed plant offspring phenotypes in a common environment. Using an integrated Bayesian model, we show that increased offspring biomass in response to warming arose through changes in the genetic composition of populations. In contrast, increased resistance to herbivory arose through a shift in plant metabolomic profiles without genetic changes, most likely by transgenerational induction of defences. Importantly, while increased resistance was costly at ambient temperatures, warming removed this constraint and favoured both vigorous and better defended plants under biocontrol. Climate warming may thus decrease biocontrol efficiency and promote Ambrosia invasion, with potentially serious economic and health consequences.Standard niche modelling is based on probabilistic inference from organismal occurrence data but does not benefit yet from genome-scale descriptions of these organisms. This study overcomes this shortcoming by proposing a new conceptual niche that resumes the whole metabolic capabilities of an organism. The so-called metabolic niche resumes well-known traits such as nutrient needs and their dependencies for survival. Despite the computational challenge, its implementation allows the detection of traits and the formal comparison of niches of different organisms, emphasising that the presence-absence of functional genes is not enough to approximate the phenotype. Further statistical exploration of an organism's niche sheds light on genes essential for the metabolic niche and their role in understanding various biological experiments, such as transcriptomics, paving the way for incorporating better genome-scale description in ecological studies.Determination of the atomic structure of solid surfaces typically depends on comparison of measured properties with simulations based on hypothesized structural models. For simple structures, the models may be guessed, but for more complex structures there is a need for reliable theory-based search algorithms. So far, such methods have been limited by the combinatorial complexity and computational expense of sufficiently accurate energy estimation for surfaces. However, the introduction of machine learning methods has the potential to change this radically. SGC-CBP30 in vivo Here, we demonstrate how an evolutionary algorithm, utilizing machine learning for accelerated energy estimation and diverse population generation, can be used to solve an unknown surface structure-the (4×4) surface oxide on Pt3 Sn(111)-based on limited experimental input. The algorithm is efficient and robust, and should be broadly applicable in surface studies, where it can replace manual, intuition based model generation.Functions of protein molecules in nature are closely associated with their well-defined three-dimensional structures and dynamics in body fluid. So far, many efforts have been made to reveal the relation of protein structure, dynamics, and function, but the structural origin of protein dynamics, especially for secondary structures as building blocks of conformation transition, is still ambiguous. Here we theoretically uncover the collective vibrations of elastic poly-alanine α-helices and find vibration patterns that are distinctively different over residue numbers ranging from 20 to 80. Contrary to the decreasing vibration magnitude from ends to the middle region for short helices, the vibration magnitude for long helices takes the minimum at approximately 1/5 of helix length from ends but reaches a peak at the center. Further analysis indicates that major vibrational modes of helical structures strongly depend on their lengths, where the twist mode dominates in the vibrations of short helices while the bend mode dominates the long ones analogous to an elastic Euler beam. The helix-coil transition pathway is also affected by the alternation of the first-order mode in helices with different lengths. The dynamic properties of the helical polypeptides are promising to be harnessed for de novo design of protein-based materials and artificial biomolecules in clinical treatments.Porosity is a fundamental property of metal-organic frameworks (MOFs). However, the role of the pore size has always been underestimated in MOF-based luminescent sensors for enantioselective sensing. The construction of isoreticular MOFs (IRMOFs) with variable pore sizes and the synergy between chirality and luminescence is challenging. Herein, a general strategy was developed to introduce chirality into two well-known IRMOF-74 analogs with nanochannels of identical shapes but different pore sizes by functionalizing the open metal site under mild conditions. To enhance the detection accuracy, a second luminescent center was introduced into the IRMOF-74 system to achieve ratiometric sensing. The two bifunctionalized IRMOF-74 compounds exhibited pore-size-dependent sensing performance for enantiomers. This study not only provides a convenient method to construct chiral MOFs as advanced sensing materials but also reveals the fundamental of the pores in MOF-based luminescent sensors.Aluminum-sulfur (Al-S) batteries of ultrahigh energy-to-price ratios are a promising energy storage technology, while they suffer from a large voltage gap and short lifespan. Herein, we propose an electrocatalyst-boosting quasi-solid-state Al-S battery, which involves a sulfur-anchored cobalt/nitrogen co-doped graphene (S@CoNG) positive electrode and an ionic-liquid-impregnated metal-organic framework (IL@MOF) electrolyte. The Co-N4 sites in CoNG continuously catalyze the breaking of Al-Cl and S-S bonds and accelerate the sulfur conversion, endowing the Al-S battery with a shortened voltage gap of 0.43 V and a high discharge voltage plateau of 0.9 V. In the quasi-solid-state IL@MOF electrolytes, the shuttle effect of polysulfides has been inhibited, which stabilizes the reversible sulfur reaction, enabling the Al-S battery to deliver 820 mAh g-1 specific capacity and 78 % capacity retention after 300 cycles. This finding offers novel insights to design Al-S batteries for stable energy storage.Currently, completely abiotic channel systems that concurrently reproduce the high selectivity and high permeation rate of natural protein channels are rare. Here, we provide one such biomimetic channel system, i.e., a novel family of helically folded hybrid amide foldamers that can serve as powerful artificial proton channels to mimic key transport features of the exceptionally selective Matrix-2 (M2) proton channels. Possessing an angstrom-scale tubular pore 3 Å in diameter, these low water permeability artificial channels transport protons at a rate 1.22 and 11 times as fast as gramicidin A and M2 channels, respectively, with exceptionally high selectivity factors of 167.6, 122.7, and 81.5 over Cl- , Na+ , and K+ ions. Based on the experimental and computational findings, we propose a novel proton transport mechanism where a proton may create a channel-spanning water chain from two or more short water chains to facilitate its own transmembrane flux via the Grotthuss mechanism.