Analysis of the complete genome sequence of Paenibacillus sp. lzh-N1 reveals its antagonistic ability.

BACKGROUND: Plant diseases caused by pathogenic fungi are devastating. However, commonly used fungicides are harmful to the environment, and some are becoming ineffective due to fungal resistance. Therefore, eco-friendly biological methods to control pathogenic fungi are urgently needed. RESULTS: In this study, a strain, Paenibacillus sp. lzh-N1, that could inhibit the growth of the pathogenic fungus Mycosphaerella sentina (Fr) Schrorter was isolated from the rhizosphere soil of pear trees, and the complete genome sequence of the strain was obtained, annotated, and analyzed to reveal the genetic foundation of its antagonistic ability. The entire genome of this strain contained a circular chromosome of 5,641,488 bp with a GC content of 45.50%. The results of species identification show that the strain belongs to the same species as P. polymyxa Sb3-1 and P. polymyxa CJX518. Sixteen secondary metabolic biosynthetic gene clusters were predicted by antiSMASH, including those of the antifungal peptides fusaricidin B and paenilarvins. In addition, biofilm formation-related genes containing two potential gene clusters for cyclic lactone autoinducer, a gene encoding S-ribosylhomocysteine lyase (LuxS), and three genes encoding exopolysaccharide biosynthesis protein were identified. CONCLUSIONS: Antifungal peptides and glucanase biosynthesized by Paenibacillus sp. lzh-N1 may be responsible for its antagonistic effect. Moreover, quorum sensing systems may influence the biocontrol activity of this strain directly or indirectly.

Deoxygenative Nucleophilic Phosphonation and Electrophilic Alkylation of Secondary Amides: A Facile Access to Quaternary α-Aminophosphonates.

The widespread occurrence and synthetic accessibility of amides render them valuable precursors for the synthesis of diverse nitrogen-containing compounds. Herein, we present a metal-free and streamlined synthetic strategy for the synthesis of quaternary α-aminophosphonates. This approach involves sequential deoxygenative nucleophilic phosphonation and versatile electrophilic alkylation of secondary amides in a one-pot fashion. Notably, this method enables the direct bis-functionalization of secondary amides with both nucleophiles and electrophiles for the first time, with simple derivatization leading to valuable free α-aminophosphonates by hydrolysis. The protocol has the advantages of operational simplicity, broad functional-group compatibility, environmental friendliness, and scalability to multigram quantities.

Practical Synthesis of Chiral α-Aminophosphonates with Weak Bonding Organocatalysis at ppm Loading.

α-Aminophosphonic acids as an important class of bioisosteres of α-amino acids demonstrate various biologically important activities. We report here the development of a highly enantioselective isomerization of α-iminophosphonates enabled by an extraordinarily efficient organocatalyst. This organocatalyst afforded a total turnover number (TON) of 20,000-1,000,000 for a wide range of α-alkyl iminophosphonates. Even at a parts-per-million (ppm) loading, this catalyst achieved a complete reaction in greater than 93% enantiomeric excess (ee). Computational studies revealed that this small-molecule catalyst achieved enzyme-like efficiency via a network of weak bonding interactions that effectively preorganized the substrate and catalyst toward a transition-state-like complex. Considering the substrate tolerance, catalytic efficiency, and mechanism, this organocatalyst could be regarded as a small-molecule isomerase.

Toxicokinetics of selenate in earthworm sub-tissues and potential bio-accessibility assessment of earthworm-derived selenium.

Selenium (Se) pollution is mainly caused by anthropogenic activities, and the resulting biosecurity concerns have garnered significant attention in recent years. Using one-compartmental toxicokinetic (TK) modelling, this study explored the kinetic absorption, sub-tissue distribution, and elimination processes of the main Se species (selenate, Se(VI)) in the cultivated aerobic soil of the earthworm Eisenia fetida. The bio-accessibility of earthworm-derived Se was assessed using an in vitro simulated gastrointestinal digestion test to evaluate its potential trophic risk. The results demonstrated that Se accumulated in the pre-clitellum (PC) and total tissues (TT) of earthworms in a time- and dose-dependent manner. The highest Se levels in the PC, post-clitellum (PoC), and TT were 70.54, 57.93, and 64.26 mg/kg during the uptake phase, respectively. The kinetic Se contents in the earthworms PC and TT were consistent with the TK model but not with PoC. The earthworm TT exhibited a faster uptake (Kus = 0.83-1.02 mg/kg/day) and elimination rate of Se (Kee = 0.044-0.049 mg/kg/day), as well as a shorter half-life time (LT1/2 = 15.88-14.22 days) than PC at low soil Se levels (≤5 mg/kg). Conversely, the opposite trend was observed with higher Se concentrations (10 and 20 mg/kg). These results are likely attributable to the tissue specificity and concentration of the toxicant. Earthworms PC and TT exhibited a higher kinetic Se accumulation factor (BAFk) than steady-state BAF (BAFss), with values ranging from 8 to 24 and 3-13, respectively. Furthermore, the bio-accessibility of earthworm-derived Se to poultry ranged from 66.25 % to 84.35 %. As earthworms are at the bottom of the terrestrial food chain, the high bio-accessibility of earthworm-derived Se poses a potential risk to predators. This study offers data support and a theoretical foundation for understanding the biological footprint of soil Se and its toxicological impacts and ecological hazards.

Experimental upstream transmission of continuous variable quantum key distribution access network.

Continuous variable quantum key distribution that can be implemented using only low-cost and off-the-shelf components reveals great potential in practical large-scale realization. Access networks, as a modern network necessity, connect many end-users to the network backbone. In this work, we first demonstrate upstream transmission quantum access networks using continuous variable quantum key distribution. A two-end-user quantum access network is then experimentally realized. Through phase compensation, data synchronization, and other technical upgrades, we achieve a secret key rate of the total network of 390 kbits/s. In addition, we extend the case of a two-end-user quantum access network to the case of a multiplicity of users, and analyze the network capacity in the case of a multiplicity of users by measuring the additive excess noise from different time slots.

Integrative analysis of γδT cells and dietary factors reveals predictive values for autism spectrum disorder in children.

BACKGROUND: Autism spectrum disorder (ASD) includes a range of multifactorial neurodevelopmental disabilities characterized by a variable set of neuropsychiatric symptoms. Immunological abnormalities have been considered to play important roles in the pathogenesis of ASD, but it is still unknown which abnormalities are more prominent. METHODS: A total of 105 children with ASD and 105 age and gender-matched typically developing (TD) children were recruited. An eating and mealtime behavior questionnaire, dietary habits, and the Bristol Stool Scale were investigated. The immune cell profiles in peripheral blood were analyzed by flow cytometry, and cytokines (IFN-γ, IL-8, IL-10, IL-17A, and TNF-α) in plasma were examined by Luminex assay. The obtained results were further validated using an external validation cohort including 82 children with ASD and 51 TD children. RESULTS: Compared to TD children, children with ASD had significant eating and mealtime behavioral changes and gastrointestinal symptoms characterized by increased food fussiness and emotional eating, decreased fruit and vegetable consumption, and increased stool astriction. The proportion of γδT cells was significantly higher in children with ASD than TD children (ß: 0.156; 95% CI: 0.888 âˆ¼ 2.135, p < 0.001) even after adjusting for gender, eating and mealtime behaviors, and dietary habits. In addition, the increased γδT cells were evident in all age groups (age < 48 months: ß: 0.288; 95% CI: 0.420 âˆ¼ 4.899, p = 0.020; age ≥ 48 months: ß: 0.458; 95% CI: 0.694 âˆ¼ 9.352, p = 0.024), as well as in boys (ß: 0.174; 95% CI: 0.834 âˆ¼ 2.625, p < 0.001) but not in girls. These findings were also confirmed by an external validation cohort. Furthermore, IL-17, but not IFN-γ, secretion by the circulating γδT cells was increased in ASD children. Machine learning revealed that the area under the curve in nomogram plots for increased γδT cells combined with eating behavior/dietary factors was 0.905, which held true in both boys and girls and in all the age groups of ASD children. The decision curves showed that children can receive significantly higher diagnostic benefit within the threshold probability range from 0 to 1.0 in the nomogram model. CONCLUSIONS: Children with ASD present with divergent eating and mealtime behaviors and dietary habits as well as gastrointestinal symptoms. In peripheral blood, γδT cells but not αßT cells are associated with ASD. The increased γδT cells combined with eating and mealtime behavior/dietary factors have a high value for assisting in the diagnosis of ASD.

Intermolecular Formal Cycloaddition of Indoles with Bicyclo[1.1.0]butanes by Lewis Acid Catalysis.

Herein, we develop a new approach to directly access architecturally complex polycyclic indolines from readily available indoles and bicyclo[1.1.0]butanes (BCBs) through formal cycloaddition promoted by commercially available Lewis acids. The reaction proceeded through a stepwise pathway involving a nucleophilic addition of indoles to BCBs followed by an intramolecular Mannich reaction to form rigid indoline-fused polycyclic structures, which resemble polycyclic indole alkaloids. This new reaction tolerated a wide range of indoles and BCBs, thereby allowing the one-step construction of various rigid indoline polycycles containing up to four contiguous quaternary carbon centers.

TTR exon-humanized mouse optimal for verifying new therapies for FAP.

Familial amyloidotic polyneuropathy (FAP) is caused by a mutation in the transthyretin (TTR) gene. In addition, deposition of wild-type TTR can cause senile systemic amyloidosis (SSA). To date, we have produced several transgenic mouse models for FAP and SSA by introducing TTR genes with different promoters or mutations. However, mouse TTR can associate with human TTR to produce hybrid tetramers in transgenic mice. Thus, these transgenic mice cannot be used to test the efficacy of a new therapy. In this study, we attempted to construct an optimized mouse model to verify a new therapy. The TTR gene consists of 4 exons and 3 introns. We prepared two gRNAs, one for the exon 1 and the other for exon 4, and a single donor vector carrying the whole TTR gene in which mouse exons were replaced with human exons. Using these vectors, we produced a TTR exon-humanized mouse with human exons and mouse introns using genome editing technology. These TTR exon-humanized mice showed normal TTR expression patterns in terms of serum TTR level and spatial specificity. These TTR exon-humanized mice will be useful for devising new treatment methods for FAP, including gene therapy.

Sensitive vapor detection with hollow thin film arrays.

In this manuscript, we explored the performance of a hollow thin film array (HTFA) for the detection of HCl vapor based on fluorescence quenching. The HTFA structure was fabricated by manually stacking layers of an active thin film and a supporting film, alternately, with a hollow structure in each supporting film. The total penetration depth of vapor molecules in the HTFA sample is 2n times increased, where n is the layer number of the active thin film. We tested the sensing performance of the HTFA sample using fluorescence emission and laser emission in a Fabry-Pérot (FP) microcavity. In the fluorescence sensing, the sensing efficiency increases with the vapor concentration, and can be as high as 80% with a vapor concentration of 400 ppm. While in the laser sensing, the efficiency can achieve 100% with an external pump intensity three times of the lasing threshold at a vapor concentration of 85 ppm. The HTFA sample is not only suitable for vapor detection but also suitable for molecule detection in liquid.

Synthesis of remote fluoroalkenyl ketones by photo-induced ring-opening addition of cyclic alkoxy radicals to fluorinated alkenes.

Fluoroalkenyl moieties are often used as carbonyl mimics in medicine preparation, and thus the development of facile routes for the synthesis of such compounds is of great importance. In this work, we report a photocatalytic ring-opening addition of cyclic alcohols to α-(trifluoromethyl)styrenes, which underwent a proton-coupled electron transfer and ß-scission process, delivering a great variety of remote gem-difluoroalkenyl ketone derivatives. This methodology can also be applied in the reaction of gem-difluorostyrenes and 1,1,2-trifluorostyrenes to access monofluoro- and 1,2-difluoroalkenyl ketones.

Propagation of Spin Waves in a 2D Vortex Network.

Efficient propagation of spin waves in a magnetically coupled vortex is crucial to the development of future magnonic devices. Thus far, only a double vortex can serve as spin-wave emitter or oscillator; the propagation of spin waves in the higher-order vortex is still lacking. Here, we experimentally realize a higher-order vortex (2D vortex network) by a designed nanostructure, containing four cross-type chiral substructures. We employ this vortex network as a waveguide to propagate short-wavelength spin waves (∼100 nm) and demonstrate the possibility of guiding spin waves from one vortex to the network. It is observed that the spin waves can propagate into the network through the nanochannels formed by the Bloch-Néel-type domain walls, with a propagation decay length of several micrometers. This technique paves the way for the development of low-energy, reprogrammable, and miniaturized magnonic devices.

Pellets of phospholipids and d-glucose with improved intestinal absorption and oral bioavailability of salvianolic acid B.

Salvianolic acid B (SAB) is a widely used cardioprotective agent, while its clinical application was limited by poor intestinal absorption and low oral bioavailability. In this study, SAB phospholipid (SP) complex was first prepared to improve the lipophilicity of SAB and then combined with d-glucose to further enhance intestinal absorption. Compared with free SAB, SP or the mixture of SAB and d-glucose, combination of SP and d-glucose showed higher intestinal absorption evidenced by increased effective permeation coefficient (Peff) in the in situ single-pass intestinal perfusion (SPIP) assay. Subsequently, SP and d-glucose at mass ratio of 1:6, with the highest Peff of SAB, were chosen for the preparation of complexed pellets to improve oral absorption efficiency of SAB. As expected, the obtained pellets significantly enhanced oral bioavailability of SAB in the pharmacokinetic study characterized by increasing Cmax and AUC0-t of SAB by 14.88-fold and 5.02-fold than free SAB, respectively. In conclusion, combination of d-glucose in SP pellets can effectively improve the intestinal absorption and oral bioavailability of SAB.

Regio- and Diastereoselective Formal [2+2] Cycloaddition of Allenes with Amino-Functionalized Alkenes by Rare-Earth-Catalyzed C(sp2 )-H Activation.

The [2+2] cycloaddition of allenes with alkenes is of much interest and importance as a straightforward route for the construction of four-membered carbocycles but has remained much underexplored to date. Herein we report for the first time the intermolecular regio- and diastereoselective formal [2+2] cycloaddition of a wide range of allenes with amino-functionalized alkenes by half-sandwich rare-earth catalysts. The reaction proceeded through an allene C(sp2 )-H activation mechanism initiated by the site-selective deprotonation of the allene unit by a rare-earth metal alkyl species followed by alkene insertion into the resulting metal-allenyl bond and the subsequent intramolecular cycloaddition to an allene C=C bond. This protocol offers a unique route for the synthesis of a new family of cyclobutane and cyclobutene derivatives which were difficult to access previously.

Palladium-catalyzed post-Ugi arylative dearomatization/Michael addition cascade towards plicamine analogues.

A palladium-catalyzed intramolecular cyclization of Ugi-adducts via a cascade dearomatization/aza-Michael addition process has been developed. Diverse plicamine analogues are constructed in a rapid, highly efficient and step-economical manner, through the combination of an Ugi-4CR and a palladium-catalyzed dearomatization. The synthetic utility of this approach is illustrated by further functional group transformations.

CO2 Activation by Lewis Pairs Generated Under Copper Catalysis Enables Difunctionalization of Imines.

Integration of distinct substrate activation modes in a catalytic circle is critical for the development of new, powerful synthetic methodologies toward complex and value-added chemicals from simple and readily available feedstocks. Here, we describe a highly selective difunctionalization of imines through incorporation of activation of CO2 by intramolecular N/B Lewis pairs into a copper catalytic cycle. Experimental and computational studies on the mechanistic aspect revealed an α-borylalkylamido intermediate, a metal amide-based Lewis pair formed by borylation of a C-N double bond, and enabled an unprecedented CO2 fixation pattern that is in sharp contrast to the traditional CO2 insertion into transition-metal-element bonds. The unique lithium cyclic boracarbamate products could be easily transformed into multifunctional N-carboxylated α-amino boronates. The highly diastereoselective reactions of chiral N-tert-butanesulfinyl aldimines were also achieved. We hope that our findings may inspire further development of selective multicomponent reactions by incorporation of Lewis pair chemistry into transition-metal catalysis.

Carboxylation Reactions with Carbon Dioxide Using N-Heterocyclic Carbene-Copper Catalysts.

The development of versatile catalyst systems and new transformations for the utilization of carbon dioxide (CO2 ) is of great interest and significance. This Personal Account reviews our studies on the exploration of the reactions of CO2 with various substrates by the use of N-heterocyclic carbene (NHC)-copper catalysts. The carboxylation of organoboron compounds gave access to a wide range of carboxylic acids with excellent functional group tolerance. The C-H bond carboxylation with CO2 emerged as a straightforward protocol for the preparation of a series of aromatic carboxylic esters and butenoates from simple substrates. The hydrosilylation of CO2 with hydrosilanes provided an efficient method for the synthesis of silyl formate on gram scale. The hydrogenative or alkylative carboxylation of alkynes, ynamides and allenamides yielded useful α,ß-unsaturated carboxylic acids and α,ß-dehydro amino acid esters. The boracarboxylation of alkynes or aldehydes afforded the novel lithium cyclic boralactone or boracarbonate products, respectively. The NHC-copper catalysts generally featured excellent functional group compatibility, broad substrate scope, high efficiency, and high regio- and stereoselectivity. The unique electronic and steric properties of the NHC-copper units also enabled the isolation and structural characterization of some key intermediates for better understanding of the catalytic reaction mechanisms.

Access to Polycyclic Azepino[5,4,3-cd]indoles via a Gold-Catalyzed Post-Ugi Dearomatization Cascade.

The development of a rapid and diverse access to complex natural product-like 3,4-fused indole scaffolds has always attracted considerable attention from synthetic and medicinal communities. We herein disclose a modular and straightforward protocol to prepare the densely substituted polycyclic azepino[5,4,3-cd]indole scaffolds. This synthetic process involves an Ugi four-component reaction from easily available starting materials and a gold-catalyzed post-Ugi domino dearomatization/Michael addition sequence, enabling facile access to the highly functionalized azepino[5,4,3-cd]indole core with excellent chemo-, regio-, and diastereoselectivity.

Indole/isatin-containing hybrids as potential antibacterial agents.

The emergence and worldwide spread of drug-resistant bacteria have already posed a serious threat to human life, creating the urgent need to develop potent and novel antibacterial drug candidates with high efficacy. Indole and isatin (indole-2,3-dione) present a wide structural and mechanistic diversity, so their derivatives possess various pharmacological properties and occupy a salient place in the development of new drugs. Indole/isatin-containing hybrids, which demonstrate a promising activity against a panel of clinically important Gram-positive and Gram-negative bacteria, are privileged scaffolds for the discovery of novel antibacterial candidates. This review, covering articles published between January 2015 and May 2020, focuses on the development and structure-activity relationship (SAR) of indole/isatin-containing hybrids with potential application for fighting bacterial infections, to facilitate further rational design of novel drug candidates.

Facile construction of diverse polyheterocyclic scaffolds via gold-catalysed dearomative spirocyclization/1,6-addition cascade.

A gold-catalysed post-Ugi chemo- and diastereoselective cascade dearomative spirocyclization/1,6-addition sequence is disclosed for the synthesis of diverse fused polyheterocyclic scaffolds bearing indole, pyrrole, benzothiophene, furan or electron-rich arene moieties from easily available building blocks. The effectiveness and efficiency of this diversity-oriented approach has been proved in the rapid construction of 28 fused polyheterocyclic scaffolds with a good building-block variability and structural complexity in two operational steps.

A gold-triggered dearomative spirocarbocyclization/Diels-Alder reaction cascade towards diverse bridged N-heterocycles.

A rapid approach for the diversity-oriented synthesis of complex bridged polycyclic N-heterocycles from readily available starting materials in two operational steps has been developed. This strategy firstly introduces molecular diversity by an Ugi four-component reaction, and then achieves these bridged N-heterocycles via an efficient gold-triggered chemo- and diastereoselective cascade non-oxidative ortho-dearomative spirocarbocyclization/Diels-Alder reaction sequence. The application of microwave irradiation for this cascade process efficiently shortens the reaction time to 10 minutes and improves the diastereoselectivity.