Although single-atomically dispersed metal-N
on carbon support (M-NC) has great potential in heterogeneous catalysis, the scalable synthesis of such single-atom catalysts (SACs) with high-loading ...metal-N
is greatly challenging since the loading and single-atomic dispersion have to be balanced at high temperature for forming metal-N
. Herein, we develop a general cascade anchoring strategy for the mass production of a series of M-NC SACs with a metal loading up to 12.1 wt%. Systematic investigation reveals that the chelation of metal ions, physical isolation of chelate complex upon high loading, and the binding with N-species at elevated temperature are essential to achieving high-loading M-NC SACs. As a demonstration, high-loading Fe-NC SAC shows superior electrocatalytic performance for O
reduction and Ni-NC SAC exhibits high electrocatalytic activity for CO
reduction. The strategy paves a universal way to produce stable M-NC SAC with high-density metal-N
sites for diverse high-performance applications.
Scope
Tyrosol is one of the main polyphenolic compounds in extra virgin olive oil (EVOO) and its role in combating obesity is unknown. Thus, this study is designed to investigate the effect of ...tyrosol consumption on obesity and its underlying mechanisms in high‐fat diet (HFD)‐induced mice.
Methods and results
After supplementation with 0.2% (wt/wt) tyrosol for 16 weeks, the final body weight, and the levels of plasma triacylglycerol (TG), total cholesterol (TC), and fasting glucose are significantly decreased when compared with HFD group. Furthermore, tyrosol may act as a ligand which binds with nuclear hormone receptor peroxisome proliferator‐activated receptor alpha (PPARα). Uncoupling protein 1 (UCP1), iodothyronine deiodinase 2 (DIO2), PPAR‐γ coactivator‐1α (PGC‐1α), and PR domain containing 16 (PRDM16), the downstream genes of PPARα which are related to thermogenic function of adipocytes, are significantly increased in both brown adipose tissue (BAT) and inguinal white adipose tissue (iWAT) after tyrosol administration. In addition, tyrosol changes the community composition of gut microbiota, including decreasing the ratio of Firmicutes to Bacteroidetes, and increasing the relative abundance of family muribaculaceae, genus Blautia and Lachnospiraceae_bacterium_28_4.
Conclusion
Tyrosol consumption attenuates obesity and related symptoms in HFD‐fed mice probably via the modulation of PPARα‐thermogenesis and gut microbiota.
The tyrosol intervention decreases body weight gain, serum glucose and lipid levels in high fat diet induced obese mice. The underlying mechanisms including promoted expression of thermogenic genes in brown adipose tissue and inguinal white adipose tissue, as well as changed community composition of gut microbiota.
Isolated from a wide range of sources, the genus Paenibacillus comprises bacterial species relevant to humans, animals, plants, and the environment. Many Paenibacillus species can promote crop growth ...directly via biological nitrogen fixation, phosphate solubilization, production of the phytohormone indole-3-acetic acid (IAA), and release of siderophores that enable iron acquisition. They can also offer protection against insect herbivores and phytopathogens, including bacteria, fungi, nematodes, and viruses. This is accomplished by the production of a variety of antimicrobials and insecticides, and by triggering a hypersensitive defensive response of the plant, known as induced systemic resistance (ISR). Paenibacillus-derived antimicrobials also have applications in medicine, including polymyxins and fusaricidins, which are nonribosomal lipopeptides first isolated from strains of Paenibacillus polymyxa. Other useful molecules include exo-polysaccharides (EPS) and enzymes such as amylases, cellulases, hemicellulases, lipases, pectinases, oxygenases, dehydrogenases, lignin-modifying enzymes, and mutanases, which may have applications for detergents, food and feed, textiles, paper, biofuel, and healthcare. On the negative side, Paenibacillus larvae is the causative agent of American Foulbrood, a lethal disease of honeybees, while a variety of species are opportunistic infectors of humans, and others cause spoilage of pasteurized dairy products. This broad review summarizes the major positive and negative impacts of Paenibacillus: its realised and prospective contributions to agriculture, medicine, process manufacturing, and bioremediation, as well as its impacts due to pathogenicity and food spoilage. This review also includes detailed information in Additional files 1, 2, 3 for major known Paenibacillus species with their locations of isolation, genome sequencing projects, patents, and industrially significant compounds and enzymes. Paenibacillus will, over time, play increasingly important roles in sustainable agriculture and industrial biotechnology.
Summary
Bacterial canker disease is considered to be one of the most destructive diseases of tomato (Solanum lycopersicum), and is caused by the seed‐borne Gram‐positive bacterium Clavibacter ...michiganensis ssp. michiganensis (Cmm). This vascular pathogen generally invades and proliferates in the xylem through natural openings or wounds, causing wilt and canker symptoms. The incidence of symptomless latent infections and the invasion of tomato seeds by Cmm are widespread. Pathogenicity is mediated by virulence factors and transcriptional regulators encoded by the chromosome and two natural plasmids. The virulence factors include serine proteases, cell wall‐degrading enzymes (cellulases, xylanases, pectinases) and others. Mutational analyses of these genes and gene expression profiling (via quantitative reverse transcription‐polymerase chain reaction, transcriptomics and proteomics) have begun to shed light on their roles in colonization and virulence, whereas the expression of tomato genes in response to Cmm infection suggests plant factors involved in the defence response. These findings may aid in the generation of target‐specific bactericides or new resistant varieties of tomato. Meanwhile, various chemical and biological controls have been researched to control Cmm. This review presents a detailed investigation regarding the pathogen Cmm, bacterial canker infection, molecular interactions between Cmm and tomato, and current perspectives on improved disease management.
In gravitational-wave (GW) astronomy accurate measurement of the source parameters, such as mass, relies on accurate waveform templates. Currently, templates are developed assuming that a source, ...such as a stellar-mass binary black hole (BBH), is residing in a vacuum. However, astrophysical models predict that BBHs could form in gaseous environments, such as common envelopes, stellar cores, and accretion disks of active galactic nuclei. Here we revisit the impact of gas on the GW waveforms of BBHs with a focus on the early inspiral phase when the GW frequency is around milli-Hertz. We show that for these BBHs, gas friction could dominate the dynamical evolution and hence duplicate chirp signals. The relevant hydrodynamical timescale, τgas, could be much shorter than the GW radiation timescale, τgw, in the above astrophysical scenarios. As a result, the observed chirp mass is higher than the real one by a factor of if the gas effect is ignored in the data analysis. This kind of error also results in an overestimation of the source distance by a factor of . By performing matched-filtering analysis in the milli-Hertz band, we prove that the gas-dominated signals are practically indistinguishable from the chirp signals of those more massive BBHs residing in a vacuum environment. Such fake massive objects in the milli-Hertz band, if not appropriately accounted for in the future, may alter our understanding of the formation, evolution, and detection of BBHs.
Electrocatalytic N2 reduction to NH3 is an attractive method for artificial N2 fixation at ambient conditions. Herein, we demonstrate that Fe-NC materials could be efficient for electrochemical N2 ...reduction reaction (NRR) using iron phthalocyanine (FePc) with a well-defined FeN4 configuration as a model catalyst. By uniformly loading FePc molecules on porous carbon, it exhibits a high electrocatalytic activity for NRR with a NH3 yield rate of 137.95 μg h–1 mg–1 FePc at a low potential of −0.3 V (vs RHE). Importantly, by making comparisons with phthalocyanine without the Fe center and performing control and poisoning experiments together with theoretical calculations, we identify the Fe center in FeN4 as the most active site for NRR among five possible sites in FePc and discover that the preferred route is the alternating pathway of N2 on Fe. These results open up opportunities for further exploring metal-nitrogen-carbon materials for highly efficient electrochemical N2 fixation and NH3 production.
Paenibacillus polymyxa is a plant-growth promoting rhizobacterium that could be exploited as an environmentally friendlier alternative to chemical fertilizers and pesticides. Various strains have ...been isolated that can benefit agriculture through antimicrobial activity, nitrogen fixation, phosphate solubilization, plant hormone production, or lignocellulose degradation. However, no single strain has yet been identified in which all of these advantageous traits have been confirmed.
P. polymyxa CR1 was isolated from degrading corn roots from southern Ontario, Canada. It was shown to possess in vitro antagonistic activities against the common plant pathogens Phytophthora sojae P6497 (oomycete), Rhizoctonia solani 1809 (basidiomycete fungus), Cylindrocarpon destructans 2062 (ascomycete fungus), Pseudomonas syringae DC3000 (bacterium), and Xanthomonas campestris 93-1 (bacterium), as well as Bacillus cereus (bacterium), an agent of food-borne illness. P. polymyxa CR1 enhanced growth of maize, potato, cucumber, Arabidopsis, and tomato plants; utilized atmospheric nitrogen and insoluble phosphorus; produced the phytohormone indole-3-acetic acid (IAA); and degraded and utilized the major components of lignocellulose (lignin, cellulose, and hemicellulose).
P. polymyxa CR1 has multiple beneficial traits that are relevant to sustainable agriculture and the bio-economy. This strain could be developed for field application in order to control pathogens, promote plant growth, and degrade crop residues after harvest.
The 2,2‐dimethyl‐2H‐chromene motif is widely found in many bioactive molecules, and is a privileged structure in the pharmaceutical arena. We have developed a concise and regioselective approach to ...chromenes and chromanes through an aryne‐based synthetic strategy. A practical, gram‐scale synthetic route to a chromene‐type aryne precursor was explored. Subsequently, cyclization under mild conditions afforded tetracyclic xanthone skeletons with excellent regioselectivity. Our approach provides a concise strategy for the gram‐scale synthesis of chromene‐type xanthones such as 6‐deoxyisojacareubin, cylindroxanthone D, staudtiixanthone D, brasilixanthone A and cudracuspixanthone O.
A practical synthetic route to a chromene‐type aryne precursor has been successfully designed and realized. With this key block, the total synthesis of five natural xanthones (6‐deoxyisojacareubin, cylindroxanthone D, staudtiixanthone D, brasilixanthone A, and cudracuspixanthone O) has been accomplished on the gram scale.
A three‐component umpolung cascade coupling reaction of phenols, C60, and different nucleophiles which includes H2O, alcohols, triphenylamines and carbazoles was developed. Furthermore, one‐pot ...1,4‐bisphenol coupling on C60 has been realized by this method. This practical protocol features high chemo‐ and regioselectivity, wide substrate range, easy operation and low cost, thus providing a robust method for the one‐pot synthesis of various unsymmetrical 1,4‐60fullerephenols.
Three‐component umpolung cascade reaction of phenols, C60, and nucleophiles has been developed as a practical and efficient protocol for one‐pot synthesis of diversified 1,4‐60fullerephenols.
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