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Nitrogen-doped carbon dots (NCDs) synthesized by the low-temperature sintering method show electronegativity rich in −COO–, −CO–NH–, −NH–, and −OH. The structure, morphology, and fluorescence performance of NCDs were successively characterized by Fourier-transform, infrared, X-ray photoelectron spectroscopy, scanning electron microscopy, transmission electron microscopy, photoluminescence, ultraviolet (UV), and X-ray fluorescence analyses. On the one hand, NCDs can sensitively detect Pb2+ in water with a detection limit of 3 ppb through the dual response of fluorescence emission spectra and UV absorbance spectra. On the other hand, the negatively charged NCDs combine with various positively charged heavy metal ions (Pb2+, Cu2+, Ni2+, Co2+, and Cd2+) through charge attraction and coordination to form a hydrogel, thereby removing heavy metal ions from the water. Among them, the removal rate of Pb2+ by NCDs is as high as 94.8%. It is the first time that pure NCDs have been used to remove heavy metal ions quickly and easily in the form of a reversible hydrogel. A simple way is to achieve ultrasensitive detection and high-efficiency removal of heavy metal ions in water with unitary NCDs. [ABSTRACT FROM AUTHOR]

A double-leg elevator with an electron-rich anthracene moiety at the platformlike component and an electron-deficient naphthalenediimide unit in the middle of a double-leg riglike component was prepared through “click chemistry”, in which the reversible elevator movement between different levels could be controlled upon the addition of base and acid. [ABSTRACT FROM AUTHOR]

Pathogenic microorganisms are a significant cause of food spoilage, adversely affecting both product quality and human health. This study evaluated the antifungal activities of 34 aldehydes against foodborne and plant pathogenic fungi, identifying 8 promising lead compounds. Among them, E , E -2, 4-nonadienal exhibited optimal effects against Rhizopus stolonifer with an EC 50 of 11.29 μg/mL. In vitro assays demonstrated that E , E -2, 4-nonadienal significantly impact R. stolonifer through both direct contact and fumigation. The preliminary mode of action (MOA) studies indicated that it effectively inhibited spore germination, disrupted ergosterol biosynthesis, and induced oxidative stress, affecting the permeability of the fungal cell membrane and altering mycelial morphology. Additionally, E , E -2, 4-nonadienal significantly reduced soft rot in spore-infected stored cherry tomatoes and showed low toxicity. Thus, aldehydes, exemplified by E , E -2, 4-nonadienal, are potential food and agricultural preservatives, offering efficiency, safety, and cost-effectiveness.

Naturally derived compounds show promise as treatments for microbial infections. Polyphenols, abundantly found in various plants, fruits, and vegetables, are noted for their physiological benefits including antimicrobial effects. This study introduced a new set of acylated phloroglucinol derivatives, synthesized and tested for their antifungal activity in vitro against seven different pathogenic fungi. The standout compound, 3-methyl-1-(2,4,6-trihydroxyphenyl) butan-1-one ( 2b ), exhibited remarkable fungicidal strength, with EC 50 values of 1.39 μg/mL against Botrytis cinerea and 1.18 μg/mL against Monilinia fructicola , outperforming previously screened phenolic compounds. When tested in vivo, 2b demonstrated effective antifungal properties, with cure rates of 76.26% for brown rot and 83.35% for gray mold at a concentration of 200 μg/mL, rivaling the commercial fungicide Pyrimethanil in its efficacy against B. cinerea . Preliminary research suggests that 2b' s antifungal mechanism may involve the disruption of spore germination, damage to the fungal cell membrane, and leakage of cellular contents. These results indicate that compound 2b has excellent fungicidal properties against B. cinerea and holds potential as a treatment for gray mold.

The emergence of resistant pathogens has increased the demand for alternative fungicides. The use of natural products as chemical scaffolds is a potential method for developing fungicides. HWY-289, a semisynthetic protoberberine derivative, demonstrated broad-spectrum and potent activities against phytopathogenic fungi, particularly Botrytis cinerea (with EC 50 values of 1.34 μg/mL). SEM and TEM imaging indicated that HWY-289 altered the morphology of the mycelium and the internal structure of cells. Transcriptomics revealed that it could break down cellular walls through amino acid sugar and nucleotide sugar metabolism. In addition, it substantially decreased chitinase activity and chitin synthase gene ( BcCHSV ) expression by 53.03 and 82.18% at 1.5 μg/mL, respectively. Moreover, this impacted the permeability and integrity of cell membranes. Finally, HWY-289 also hindered energy metabolism, resulting in a significant reduction of ATP content, ATPase activities, and key enzyme activities in the TCA cycle. Therefore, HWY-289 may be a potential candidate for the development of plant fungicides.

Bacterial leaf blight (BLB) caused by Xanthomonas oryzae pv oryzae ( Xoo ) is extremely harmful to rice production. The traditional control approach is to use bactericides that target key bacterial growth factors, but the selection pressure on the pathogen makes resistant strains the dominant bacterial strains, leading to a decline in bactericidal efficacy. Type III secretion system (T3SS) is a conserved and critical virulence factor in most Gram-negative bacteria, and its expression or absence does not affect bacterial growth, rendering it an ideal target for creating drugs against Gram-negative pathogens. In this work, we synthesized a range of derivatives from cryptolepine and neocryptolepine. We found that compound Z-8 could inhibit the expression of Xoo T3SS-related genes without affecting the growth of bacteria. an in vivo bioassay showed that compound Z-8 could effectively reduce the hypersensitive response (HR) induced by Xoo in tobacco and reduce the pathogenicity of Xoo in rice. Furthermore, it exhibited synergy in control of bacterial leaf blight when combined with the quorum quenching bacterial F20.

Cytochrome P450 monooxygenases (CYP450s) play an important role in the biosynthesis of natural products by activating inert C-H bonds and inserting hydroxyl groups. However, the activities of most plant-derived CYP450s are extremely low, limiting the heterologous biosynthesis of natural products. Traditional enzyme engineering methods, either rational or screening-based, are not suitable for CYP450s because of the lack of crystal structures and high-throughput screening methods for this class of enzymes. CYP725A4 is the first hydroxylase involved in the biosynthesis pathway of Taxol. Its low activity, promiscuity, and multispecificity make it a bottleneck in Taxol biosynthesis. Here, we identified key amino acids that affect the in vivo activity of CYP725A4 by constructing the ancestral enzymes of CYP725A4. We obtained positive mutants that showed an improved yield of hydroxylated products based on the key amino acids identified, providing guidance for the modification of other CYP450s involved in the biosynthesis of natural products.

In this work, a series of derivatives with disulfide bonds containing pyridine, pyrimidine, thiophene, thiazole, benzothiazole, and quinoline were designed and synthesized based on the various biological activities of allicin disulfide bond functional groups. The antimicrobial activities of the target compounds were determined, and the structure-activity relationships were discussed. Among them, compound S8 demonstrated the most potent antifungal activity in vitro against Monilinia fructicola ( M. fructicola ), with an EC 50 value of 5.92 μg/mL. Furthermore, an in vivo bioassay revealed that compound S8 exhibited equivalent curative and higher protective effects as the positive drug thiophanate methyl at a concentration of 200 μg/mL. The preliminary mechanism experiments showed that compound S8 could inhibit the growth of M. fructicola ' s hyphae in a time- and concentration-dependent manner, and compound S8 could induce the shrinkage of hyphae, disrupt the integrity of the plasma membrane, and cause the damage and leakage of cell contents. More than that, compound S5 also demonstrated an excellent antibacterial effect on Xanthomonas oryzae ( X. oryzae ), with a MIC 90 value of 1.56 μg/mL, which was superior to the positive control, thiodiazole copper.

Mechanoluminescence materials that emit light under mechanical stimulation have attracted widespread attention in sensing, anticounterfeiting, and imaging applications. In this study, a series of Sr 1- x Bi x ZnSO (0.001 ≤ x ≤ 0.1) samples was synthesized by the method of high temperature solid-state reaction. It is worth noting that the distortion degree of the SrO 3 S 3 octahedron was increased with increasing Bi 3+ concentration, and the color manipulated Sr 1- x Bi x ZnSO which can emit different photoluminescence (blue to dark blue and finally red) and mechanoluminescence (orange to red) colors is obtained. Moreover, the deep traps can stably store and provide electronic supplements in shallow traps released under mechanical stimulation. Therefore, devices made of SrZnSO:Bi 3+ phosphor and polydimethylsiloxane (PDMS) can be used as thermo-mechano-opto three-mode anticounterfeiting. The ML intensity is linear to the external load and can be utilized for stress sensing or imaging.

Based on the structural characteristics of the cryptolepine alkaloid, a series of new quindoline derivatives bearing various substituents were prepared and evaluated for their fungicidal and antibacterial activities. Bioassay results showed that compound D7 displayed superior in vitro fungicidal activities against Sclerotinia sclerotiorum , Botrytis cinerea , Fusarium graminearum , and Rhizoctonia solani with EC 50 values of 0.780, 3.62, 1.59, and 2.85 μg/mL, respectively. Compound A7 showed apparent antibacterial activities toward Xanthomonas oryzae pv. oryzae with a minimum inhibitory concentration (MIC) value of 3.12 μg/mL. Significantly, in vivo antifungal activity suggested that the curative effect (98.3%) of compound D7 was comparable to that of the positive control azoxystrobin (96.7%) at 100 μg/mL. Preliminary mechanistic studies showed that compound D7 might cause mycelial abnormality of S. sclerotiorum , cell membrane breakage, accumulation of reactive oxygen species (ROS), and inhibition of sclerotia formation. Therefore, compound D7 could be a novel broad-spectrum fungicidal candidate against plant fungal diseases.

Plant pathogenic fungi seriously affect agricultural production and are difficult to control. The discovery of new leads based on natural products is an important way to innovate fungicides. In this study, 30 natural-product-based magnolol derivatives were synthesized and characterized on the basis of NMR and mass spectroscopy. Bioactivity tests on phytopathogenic fungi ( Rhizoctonia solani , Fusarium graminearum , Botrytis cinerea , and Sclerotinia sclerotiorum ) in vitro of these compounds were performed systematically. The results showed that 11 compounds were active against four kinds of phytopathogenic fungi with EC 50 values in the range of 1.40-20.00 μg/mL, especially compound L5 that exhibited excellent antifungal properties against B. cinerea with an EC 50 value of 2.86 μg/mL, approximately 2.8-fold more potent than magnolol (EC 50 = 8.13 μg/mL). Moreover, compound L6 showed the highest antifungal activity against F. graminearum and Rhophitulus solani with EC 50 values of 4.39 and 1.40 μg/mL, respectively, and compound L7 showed good antifungal activity against S. sclerotiorum . Then, an in vivo experiment of compound L5 against B. cinerea was further investigated in vivo using infected tomatoes (curative effect, 50/200 and 36%/100 μg/mL). The physiological and biochemical studies illustrated that the primary action mechanism of compound L5 on B. cinerea might change the mycelium morphology, increase cell membrane permeability, and destroy the function of mitochondria. Furthermore, structure-activity relationship (SAR) studies revealed that hydroxyl groups play a key role in antifungal activity. To sum up, this study provides a reference for understanding the application of magnolol-based antifungal agents in crop protection.

Inspired by natural 2-quinolinecarboxylic acid derivatives, a series of quinoline compounds containing acylhydrazine, acylhydrazone, sulfonylhydrazine, oxadiazole, thiadiazole, or triazole moieties were synthesized and evaluated for their fungicidal activity. Most of these compounds exhibited excellent fungicidal activity in vitro . Significantly, compound 2e displayed the superior in vitro antifungal activity against Sclerotinia sclerotiorum , Rhizoctonia solani , Botrytis cinerea , and Fusarium graminearum with the EC 50 values of 0.39, 0.46, 0.19, and 0.18 μg/mL, respectively, and were more potent than those of carbendazim (EC 50 , 0.68, 0.14, >100, and 0.65 μg/mL, respectively). Moreover, compound 2e could inhibit spore germination of F. graminearum . Preliminary mechanistic studies showed that compound 2e could cause abnormal morphology of cell walls and vacuoles, loss of mitochondrion, increases in membrane permeability, and release of cellular contents. These results indicate that compound 2e displayed superior fungicidal activities and could be a potential fungicidal candidate against plant fungal diseases.

Rhizoctonia solani causes serious plant diseases. Neocryptolepine presented the significant antifungal activity against R . solani , however the mode of action is unclear. In this paper, we investigated the potential mode of action of neocryptolepine against R . solani integrated the proteomics and transcriptomics. Results showed that after treatment with neocryptolepine, 1012 differentially expressed proteins and 10 920 differentially expressed genes of R . solani were found, most of them were enriched in mitochondrial respiratory chain. It affected oxidative phosphorylation led to the enrichment of ROS and the decrease of MMP, and inhibited complex III activity with the inhibition rate of 63.51% at 10 μg/mL. The mitochondrial structural and function were damaged. Cytochrome b -c1 complex subunit Rieske (UQCRFS1) with the high binding score to neocryptolepine was found as a potential target. In addition, it inhibited the sclerotia formation and presented antifungal efficacy by decreasing the diameter of a wound in potato in a concentration-dependent manner. Above results indicated that neocryptolepine inhibited the complex III activity by binding UQCRFS1 and blocked the ion transfer to cause the death of R . solani mycelia. This study laid the foundation for the future development of neocryptolepine as an alternative biofungicide.

Plant diseases caused by phytopathogenic fungi reduce the yield and quality of crops. To develop novel antifungal agents, we designed and synthesized eight series of quinazolinone derivatives and evaluated their anti-phytopathogenic fungal activity. The bioassay results revealed that compounds KZL-15 , KZL-22 , 5b , 6b , 6c , 8e , and 8f exhibited remarkable antifungal activity in vitro . Especially, compound 6c displayed the highest bioactivity against Sclerotinia sclerotiorum , Pellicularia sasakii , Fusarium graminearum , and Fusarium oxysporum , displaying appreciable IC 50 values (50% inhibitory concentration) of 2.46, 2.94, 6.03, and 11.9 μg/mL, respectively. A further mechanism interrogation revealed abnormal mycelia, damaged organelles, and changed permeability of cell membranes in S. sclerotiorum treated with compound 6c . In addition, the in vivo bioassay indicated that compound 6c possessed comparable curative and protective effects (87.3 and 90.7%, respectively) to the positive control azoxystrobin (89.5 and 91.2%, respectively) at 100 μg/mL concentration against S. sclerotiorum . This work validated the potential of compound 6c as a new and promising fungicide candidate, contributing to the exploration of potent antifungal agents.

Isoleucine dioxygenase (IDO)-catalyzed hydroxylation of isoleucine is a promising method for the synthesis of the diabetic drug (2 S ,3 R ,4 S )-4-hydroxyisoleucine [(2 S ,3 R ,4 S )-4-HIL]. However, the low activity of IDO significantly limits its practical application. In this work, a high-throughput screening method was developed and directed evolution was performed on the IDO from Bacillus subtilis , resulting in a double mutant with improvements in specific activity, protein expression level, and fermentation titer of 3.2-, 2.8-, and 9.4-fold, respectively. l-Isoleucine (228 mM) was completely converted to (2 S ,3 R ,4 S )-4-HIL by the best variant with a space-time yield of up to 80.8 g L -1 d -1 , which is the highest record reported so far. With a further increase of the substrate loading to 1 M, a high conversion of 91% could also be achieved. At last, enzymatic synthesis of (2 S ,3 R ,4 S )-4-HIL was successfully carried out on a 3 L scale, indicating tremendous potential of the IDO variant I162T/T182N for green and efficient production of (2 S ,3 R ,4 S )-4-HIL.

The application of LuBO 3 :Ce 3+ (LBO:Ce) crystal as an excellent scintillation material has been limited due to its poor phase stability at high temperature or high pressure, so improving the phase stability is essential for promoting its development. Ga stabilized LuBO 3 :Ce 3+ (LGBO:Ce) is synthesized by solid-state reaction at 1200 °C. Powder X-ray diffraction patterns and Raman spectra at ambient pressure show that all the samples are pure calcite phase. In situ high-pressure synchrotron radiation XRD patterns illustrate that calcite phase LGBO:Ce exhibits more excellent phase stability than that of LBO:Ce under high pressure due to the superior compressibility of the [GaO 6 ] octahedral unit. The optical band gap of LGBO decreases from 5.58 to 4.64 eV after introducing 10% Ga, which leads to the decreased nonradiative transition and about double luminescence intensity as expected. More interestingly, the charge transition from O 2- to Ce 4+ is observed at about 290 nm in the absorption spectra. The X-ray photoelectron spectroscopy spectra indicate the ratio of Ce 4+ /Ce 3+ increases with increasing concentration of Ga 3+ , which can be attributed to the variation of energy separation between the 4f ground state of Ce 3+ and the Fermi energy level position. In contrast to the enhancement of PL intensity, the integrated X-ray excited luminescence intensity decreases after Ga 3+ incorporation attributing to the result of both decreased effective atomic number and ionization energy between 5d 1 level and conduction band. The thermal luminescence spectra show that after the incorporation of Ga 3+ the oxygen vacancy and intrinsic defects in LBO remain unchanged but that the concentration of oxygen vacancy significantly reduces. The mechanism of Ga 3+ incorporation on phase stability and luminescence properties of LBO:Ce has been proposed and discussed systematically.

A series of β-carboline oxadiazoles were synthesized, and their fungicidal activities and mechanism of action against rice sheath blight caused by Rhizoctonia solani was evaluated. The results showed that all of these compounds exhibited significant in vitro fungicidal activity. Significantly, compound 5i (EC 50 = 4.2 μg/mL) displayed the best efficacy and superior fungicidal activity compared to validamycin A (EC 50 = 197.6 μg/mL). Moreover, the in vivo test also demonstrated that compound 5i could effectively control rice sheath blight and showed higher in vivo protective and curative activities against R. solani than validamycin A. Preliminary mechanism studies revealed that compound 5i caused the loss of mitochondrial membrane potential, reactive oxygen species accumulation, cell membrane destruction, and DNA synthesis interference. These findings indicated that compound 5i displayed superior fungicidal activities against R. solani and could be a potential fungicidal candidate against rice sheath blight.

Lycoplanine A (1), a Lycopodium alkaloid with a 6/9/5 tricyclic ring skeleton fused with the γ-lactone ring and featuring an unusual 1-oxa-6-azaspiro[4.4]nonane moiety and an unprecedented 3-azabicyclo[6.3.1]dodecane unit, was isolated from the club moss Lycopodium complanatum. The structure and absolute configuration of 1 were identified by a combination of NMR spectroscopic analysis and single-crystal X-ray diffraction. Biological studies showed that 1 is a potent Ca v 3.1 T-type calcium channel (TTCC) inhibitor with an IC 50 value of 6.06 μM.

Five new Lycopodium alkaloids, phleghenrines A-D (1-4) and neophleghenrine A (5), were isolated from Phlegmariurus henryi (Baker) Ching. The structures and absolute configurations of 1-5 were determined using extensive spectroscopic data coupled with computational calculations and revealed 1-4 possess a bicyclo[3.2.2]nonane core, whereas 5 possesses an unprecedented 9-azaprotoadamantane core. Compounds 1 and 4 showed potent acetylcholinesterase (AChE) inhibitory activities, and 4 is a good lead natural product for the treatment of Alzheimer's disease.

Catalytic promiscuity is a useful, but accidental, enzyme property, so finding catalytically promiscuous enzymes in nature is inefficient. Some ancestral enzymes were branch points in the evolution of new enzymes and are hypothesized to have been promiscuous. To test the hypothesis that ancestral enzymes were more promiscuous than their modern descendants, we reconstructed ancestral enzymes at four branch points in the divergence hydroxynitrile lyases (HNL's) from esterases ∼ 100 million years ago. Both enzyme types are α/β-hydrolase-fold enzymes and have the same catalytic triad, but differ in reaction type and mechanism. Esterases catalyze hydrolysis via an acyl enzyme intermediate, while lyases catalyze an elimination without an intermediate. Screening ancestral enzymes and their modern descendants with six esterase substrates and six lyase substrates found higher catalytic promiscuity among the ancestral enzymes (P < 0.01). Ancestral esterases were more likely to catalyze a lyase reaction than modern esterases, and the ancestral HNL was more likely to catalyze ester hydrolysis than modern HNL's. One ancestral enzyme (HNL1) along the path from esterase to hydroxynitrile lyases was especially promiscuous and catalyzed both hydrolysis and lyase reactions with many substrates. A broader screen tested mechanistically related reactions that were not selected for by evolution: decarboxylation, Michael addition, γ-lactam hydrolysis and 1,5-diketone hydrolysis. The ancestral enzymes were more promiscuous than their modern descendants (P = 0.04). Thus, these reconstructed ancestral enzymes are catalytically promiscuous, but HNL1 is especially so.

Low-temperature vaterite-type LuBO(3) (π-LBO) was prepared by a solid-state reaction method at high temperature. The reasoning of the existence of vacancy-stabilized π-LBO was investigated for the first time using neutron diffraction patterns, Fourier transform infrared (FT-IR) spectra, and high-resolution transmission electron microscopy. The results clearly demonstrated that the B and O vacancies in π-LBO came into being during the heating process. The existence of an open B(3)O(9) ring consisting of BO(3) and BO(4) units in π-LBO due to the B and O vacancies was demonstrated by FT-IR. The vacuum ultraviolet-ultraviolet spectroscopic properties of π-LBO were studied in detail. In addition, the luminescence mechanism of Ce(3+) in π-LBO was put forward and discussed with that of calcite-type LuBO(3) (β-LBO).

An acceptor-donor-acceptor-type linear molecule 1(2+) containing one electron-rich naphthoxy (NP) unit and two monocharged viologen (MCV) units was synthesized. Through the noncovalent interaction of cucurbit[8]uril (CB[8]) with one NP and one MCV in 1(2+), we first obtained a [2]pseudorotaxane ([1(2+)]⊂CB[8]), and the excess CB[8] included simultaneously the two bare MCV units of two [2]pseudorotaxanes to form a [5]pseudorotaxane ([1(2+)](2)⊂[CB[8]](3)). Its transformation to [3]pseudorotaxane was achieved through detaching the two axle molecules in the presence of acid, and then the addition of base may result in a reversible switch between two different pseudorotaxanes. This novel methodology elongating reversibly linear molecules by noncovalent interactions will benefit the development of stimuli-responsive functional molecular devices.

Two stable supramolecular loops (1 and 2) were successfully constructed by the molecular recognition of cucurbit[8]uril (CB[8]) and the homoditopic bispyridinium derivatives (3 and 4). Interestingly, the interconversion of molecular loops and [2]pseudorotaxanes could be reversibly switched under neutral and acidic condition, exhibiting the controlled electrochemical and spectroscopic behaviors.

A family of lamellar mesostructured n-alkylamine borophosphates, denoted C n A-BPO (BPO stands for inorganic borophosphate layer; n = 9-15, the number of carbon atoms in the n-alkylamine chain) has been prepared hydrothermally at 160 degrees C by using neutral n-alkylamines as templates. Those C n A-BPO compounds were characterized by powder X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), thermogravimetric measurements, and differential thermal analysis (TG-DTA) as well as chemical analyses. Interestingly, these compounds may form a bilayer, a monolayer, or mixed state of bilayer and monolayer structures depending on the content of n-alkylamine. Linear relationships for both bilayer and monolayer compounds were observed between the interlayer distances and the numbers of carbon atoms in the n-alkylamine chain. The thickness of the inorganic layers, the arrangement of n-alkylamine in the interlayer space, and the composition of the compounds are proposed.