Search Results (160)

Fusarium oxysporum f. sp. radicis-lycopersici (Forl) is the etiological agent of tomato Fusarium crown and root rot (FCRR), a devastating soil-borne disease that severely compromises global tomato production. The pathogenicity of Forl has been increasingly linked to its capacity to produce phytotoxic isocassadiene-type diterpenoids. In this study, Forl was cultured in rice medium to obtain Forl cultures, which were used for the separation and identification of secondary metabolites. After removing the known metabolites, two new isocassadiene-type diterpenoid compounds, namely fusariumic acids I (1) and J (2), were isolated from the ethyl acetate extract. Their structures were identified using spectroscopic data analyses and quantum chemical calculations. This is the first report of the fusariumic acid analogs containing a hydroxyl group at position C–1 in the molecule. Fusariumic acids I (1) and J (2) exhibited significantly inhibitory activities on the hypocotyl elongation of tomato (Solanum lycopersicum) and sesame (Sesamum indicum) seedlings, as well as on the coleoptile elongation of rice (Oryza sativa var. japonica) seedlings at concentrations from 10 to 100 µg/mL. The discovery of two new phytotoxic isocassadiene-type diterpenoids expanded the diversity of secondary metabolites of Forl. Meanwhile, it provided critical insights into Forl-tomato interactions and the candidate lead compounds for the development of new herbicides as well. Full article

Perylene bisimide derivatives are typical n-type semiconductors as well as redox-active materials. However, it has been difficult to produce thin films by solution processes because of their low solubilities in organic solvents. Perylene bisimide derivatives bearing oligosiloxane moieties exhibit columnar phases over wide temperature ranges, including room temperature and high solubilities in organic solvents. The columnar phases are stabilized by nanosegregation between crystal-like one-dimensional π-stacks and liquid-like mantle consisting of oligosiloxane moieties. The electron mobility at room temperature exceeded 0.1 cm²V⁻¹s⁻¹ in the ordered columnar phases of perylene bisimide derivatives bearing four disiloxane chains. Uniaxially aligned thin films of the perylene bisimide derivatives bearing oligosiloxane moieties could be produced by a spin-coating method. The spin-coated films of the perylene bisimide derivatives bearing cyclotetrasiloxane rings could be insolubilized via in situ ring-opening polymerization by the exposure of the thin films to trifluoromethanesulfonic acid vapors. Uniaxially aligned thin films of perylene bisimide derivatives bearing an ethylene oxide chain as well as cyclotetrasiloxane rings could be doped in an aqueous solution of sodium dithionate, resulting in an anisotropic electrical conductivity. Polymerized thin films of perylene bisimide derivatives bearing a crown ether ring exhibited electrochromism in electrolyte solutions. These compounds formed 1:1 complexes with lithium triflate, exhibiting columnar phases at room temperature. The nanostructures of the complexes were stabilized by the electrostatic interaction between cationic crown-metal units and triflate anions. Full article

Volatile coordination compounds are widely used as precursors for the gas phase synthesis of functional materials. However, such complexes are still very rare for alkali metals, especially for heavy representatives of this family (potassium, rubidium, cesium) due to the tendency to form polymeric structures. This work is devoted to the exploration of a potassium hexafluoroacetylacetonate complex with 18-crown-6 ether, K(18C6)(hfac), as a unique volatile precursor with an isolated molecular structure. A convenient synthesis procedure was developed, and key structural features were identified including temperature-dependent effects. The thermal properties of the complex were studied via thermogravimetry and measurements of saturated vapor pressure using the Knudsen effusion method with mass spectrometric registration of the gas phase composition. Both from solution and the gas phase, the molecular films of K(18C6)(hfac) obtained exhibit a strictly (h00) orientation, where half of the surface cations have a coordination sphere accessible to supramolecular contacts. For the first time, the possibility of producing potassium-containing films from a fluorinated precursor by metal–organic chemical vapor deposition (MOCVD) has been demonstrated. With oxygen as the reactant gas, potassium fluoride forms and interacts with the silicon substrate, while introducing water vapor significantly reduces the fluorine content, suggesting its suitability for the preparation of oxide films. Full article

Protein phosphorylation and dephosphorylation reactions of intracellular molecules catalyzed by enzymes such as kinases and phosphatases are essential reactions in a lot of cellular functions such as intracellular signal transduction in living systems. The design and synthesis of artificial enzyme mimics are important research topics in bioorganic and bioinorganic chemistry. In this paper, we report on the construction of artificial phosphatases via the supramolecular self-assembly of compounds such as an amphiphilic bis(Zn²⁺-cyclen) (cyclen = 1,4,7,10-tetraazacyclododecane) complex, barbital derivatives modified with benzocrown ethers and boronophenyl groups, and a copper(II) ion in a two-phase solvent system. We have developed a hypothesis whereby a mono(4-nitrophenyl)phosphate (MNP) substrate coordinates to the Cu₂(µ-OH)₂ core in supramolecular complexes and is activated either by Lewis acidic units such as alkali metal (Li⁺, Na⁺ and K⁺)-benzocrown ether complexes or by boronophenyl moieties. The findings suggest that supramolecular phosphatase functionalized with a benzo-12-crown-4-Li⁺ complex shows a higher level of activity in the MNP hydrolysis of a two-phase solvent system compared with that of our previous supramolecular phosphatases in terms of hydrolysis activity and catalytic turnover. Full article

The agar diffusion method was used to test the antibacterial activity of 12 plant species against Agrobacterium tumefaciens, the bacterium that is responsible for crown gall disease. Leaf, root, or flower extracts were prepared, but not all parts were used for each of the 12 plants listed. Plant extracts from leaves exhibited higher antibacterial activity than those from flowers and roots. Furthermore, the type of solvent had a significant influence on both the antibacterial activity and the flavonoid and polyphenol content. Acetone and alcohol extracts contained higher contents of these compounds than water extracts. The strongest bacteriostatic effect was of the leaf extracts of eucalyptus (Eucalyptus nicholii L.) and St. John’s wort (Hypericum perforatum L.). Based on HPTLC analysis, eucalyptus extracts contained, among others, chlorogenic acid, hyperoside, and quercetin, while St. John’s wort extracts contained rutin, hyperoside, and quercetin. The tansy leaf extracts (Tanacetum vulgare L.) were also rich in flavonoids and phenolic acids, such as kaempferol-3-glucoside, luteolin, chlorogenic acid, cynarine, and rutin. However, a moderate inhibitory effect against the tested bacterium was found in tansy extracts, as well as hop (Humulus lupulus L.), wormwood (Artemisia absinthium L.), peppermint (Mentha piperita L.), yarrow (Achillea millefolium L.), and nettle (Urtica dioica L.) extracts. The least effective were the root extracts of dandelion (Taraxacum officinale F.H. Wiggers coll.) and valerian (Valeriana officinalis L.), as well as the flower extracts of chamomile (Matricaria chamomilla L.) and marigold (Calendula officinalis L.). Given the lack of effective chemical products and the unavailability of commercially resistant cultivars, the use of plant-based extracts for protecting against crown gall appears to be of particular interest. The preliminary results are promising and suggest that eucalyptus and St. John’s wort extracts are the most promising for controlling A. tumefaciens. Full article

Sometimes, mandatory rules for eradicating pathogens specifically target crops that hold intrinsic economic value, cultural heritage, and are a lucrative tourist attraction as well as an appealing part of the landscape due to their historical presence in the region. An example of this is the introduction of Xylella fastidiosa subsp. pauca (Xfp), mainly vectored by Philaenus spumarius to olive groves in Apulia. Twelve years after the first official report on its presence and numerous studies, this review aims to reconsider some of the quarantine measures in place to prevent the spread of Xfp. Surveys carried out within the demarcated areas have shown a low incidence of Xfp over the years ranging from 0.06% to 0.70%. Furthermore, the bacterium is now present throughout the region, from the south to the north, potentially suggesting that the bacterium may be endemic in the region. Epidemiological models have indicated low or negligible infectivity for asymptomatic trees. Rigorous vector control, achieved through the mechanical removal of eggs and juvenile forms, coupled with the contemporary reduction in the Xfp load within the olive crown using bactericidal compounds, could effectively reduce the spread of Xfp in both infected and demarcated areas. These actions could also serve as preventive measures in current free areas. Once the prevalence of both vectors and Xfp is low, only olive trees in demarcated areas that test positive for the bacterium should be uprooted. Trees within a 50 m radius of an Xfp-positive olive tree should not be removed if they test negative for Xfp upon detection. Full article

The development of dental restorative materials with improved physical and mechanical properties is an important area of research. In this study, hexaallylaminocyclotriphosphazene (HAP) was used to modify dental composites. HAP is a compound with multiple carbon-carbon bonds that can react with methacrylic resins to form a copolymer. HAP was synthesized by reacting allylamine with hexachlorocyclotriphosphazene and characterized it using ¹H and ³¹P NMR spectroscopy and MALDI-TOF mass spectrometry. Molecular dynamics simulations using the MM2 force field showed that HAP has a nanosize (the diameter of a sphere eclosing the molecule is 1.3 nm), making it a suitable nanomodifier for dental composites. Using 3D printing, samples of dental methacrylic composites containing up to 10 wt. % HAP were prepared and their physicomechanical properties and antibacterial activity against gram-positive bacteria S. mutans were studied. As a result, it was established that the maximum flexural strength (115.1 ± 10.2 MPa) is achieved with a modifier content of 5 wt.% in the composite. The maximum value of inhibition of S. mutans growth in a liquid nutrient medium is achieved with a HAP content of 10 wt.% in the sample. Furthermore, with a HAP content of more than 5 wt.% in the composite, inhibition of biofilm on the material surface is observed. The resulting composite is proposed for use as dental crowns in restorative dentistry. Full article

The increase in pineapple production has led to a significant accumulation of agro-industrial waste, underscoring the need for sustainable strategies for its utilization. The valorization of pineapple crowns presents an opportunity to produce value-added products rich in phenolic compounds, thereby reducing environmental impacts and offering accessible alternatives to small-scale producers. Among the methods for extracting phenolic compounds, maceration, Soxhlet extraction, and fermentation stand out, with the latter being considered a low-cost and more environmentally sustainable option. In this study, the objective was to compare three extraction methods (dynamic maceration, Soxhlet extraction, and fermentation) were compared to identify the most efficient method for recovering phenolic compounds from pineapple crowns. The results showed that fermentation yielded the highest total phenolic compounds of 82.3 mg GAE/g (Folin–Ciocalteu) and 64.1 mg GAE/g (Fast Blue BB), followed by maceration at 17.3 mg GAE/g (Folin–Ciocalteu) and 10.2 mg GAE/g (Fast Blue BB) and Soxhlet extraction at 2.1 mg GAE/g for both, with gallic, ferulic, and p-coumaric acids being particularly noteworthy in the fermented extract. The microorganism Bacillus sp. SMIA-2 played a significant role in the release and availability of these compounds, increasing the efficiency of the process. Thus, fermentation proves to be a sustainable and economically viable alternative for utilizing pineapple crowns, promoting the rational use of plant biomass and adding value to a low-cost, easily applicable agro-industrial byproduct. Full article

Crown gall disease, caused by soil-borne bacterial pathogens, such as Allorhizobium vitis, poses a significant threat to grapevine cultivation in Japan, particularly under environmental conditions exacerbated by climate change. Effective chemical control options are limited, highlighting the need for sustainable biocontrol strategies. In this study, we screened a library of soil bacteria with known antagonistic activity against major grapevine fungal pathogens and identified Pseudomonas sp. strain YU44 as a broad-spectrum antagonist of crown gall pathogens A. vitis and Rhizobium radiobacter. In vitro assays demonstrated that YU44 inhibits the growth of both pathogens by secreting bioactive compounds. In vivo bioassays confirmed that pretreatment with YU44 significantly suppresses crown gall formation in grapevine and rose seedlings. Additionally, YU44 application to soil near the stem base reduces disease severity in grapevine seedlings, supporting its potential as a practical biocontrol agent. Although complete disease suppression is not achieved, YU44 represents a promising environmentally friendly alternative for integrated disease management because it can complement resistant rootstocks, sanitation practices, and cultivation methods. These findings highlight YU44’s potential as an adaptive management tool for crown gall disease in the face of climate change. Full article

This research presents a detailed Life Cycle Assessment (LCA) of 26 mm Crown cork metal closures used in glass bottle packaging, with the objective of quantifying and comparing their environmental impacts across all life cycle stages. This study adheres to ISO 14040 and ISO 14044 standards and utilizes Microsoft Excel for structuring and documenting input–output data across each phase. The LCA encompasses three primary stages: raw material production (covering iron ore extraction and steel manufacturing), manufacturing processes (including metal sheet printing, forming, and packaging of closures), and the transport phase (distribution to bottling facilities). During the Life Cycle Inventory (LCI), steel production emerged as the most environmentally burdensome phase. It accounted for the highest emissions of carbon dioxide (CO₂), carbon monoxide (CO), nitrogen oxides (NO_x), and sulphur oxides (SO_x), while emissions of heavy metals and volatile organic compounds were found to be negligible. The Life Cycle Impact Assessment (LCIA) was carried out using the Eco-Indicator 99 methodology, which organizes emissions into impact categories related to human health, ecosystem quality, and resource depletion. Final weighting revealed that steel production is the dominant contributor to overall environmental impact, followed by the manufacturing stage. In contrast, transportation exhibited the lowest relative impact. The interpretation phase confirmed these findings and emphasized steel production as the critical stage for environmental optimization. This study highlights the potential for substantial environmental improvements through the adoption of low-emission steel production technologies, particularly Electric Arc Furnace (EAF) processes that incorporate high percentages of recycled steel. Implementing such technologies could reduce CO₂ emissions by up to 68%, positioning steel production as a strategic focus for sustainability initiatives within the packaging sector. Full article

Pyrogallol[4]arenes are polyhydroxylated compounds obtained by condensation between pyrogallol and different aldehydes. Depending on both the type of aldehyde (aromatic or aliphatic) and the reaction time, these compounds can be obtained in different conformations, the most common being the crown and chair conformations. Using the conventional synthesis method, it is possible to obtain, in addition to the chair or crown conformers, other molecular associations, such as dimer capsules. The research in this study focuses on the synthesis products obtained from the condensation between pyrogallol and propanal. These products were characterized using spectroscopic methods, revealing that it is possible to obtain, in addition to the crown conformation, the dimer capsule of the macrocycle. Finally, the volumetric properties of these conformers were evaluated in dimethyl sulfoxide (DMSO) solution at several temperatures. Full article

Most ash trees (Fraxinus excelsior) in Germany are infected with Hymenoscyphus fraxineus, the causative agent of ash dieback (ADB). This study investigates the phenolic content of ash leaves to evaluate their potential as indicators for monitoring ADB and to assess how this potential is affected by site and year. Fresh leaf samples were collected and immediately frozen from 14 forest plots across Germany over a period of up to four years. Phenolic compounds were quantified using both photometric assays and HPLC. The results reveal strong site-specific differences in both total phenolic content and individual phenolic profiles. Temporal differences between sampling years were less pronounced, but were frequently significant. In contrast, crown condition—a key indicator of ADB damage—had only a weak effect on phenolic content. This suggests that mature ash trees do not exhibit a clear phenol-based defence response to H. fraxineus under field conditions. Our findings underscore the complexity of phenolic dynamics in natural stands and demonstrate that no robust of phenolic biomarker for ADB could be identified in mature trees. Full article

Starting with DPPH-diradical, the corresponding dinitro-derivative was obtained in a biphasic system using solid sodium nitrite and 15-crown-5 ether as the nitrating reagents. The new compound was characterized using 1H- and 13C-NMR, IR, and UV-Vis. After undergoing oxidation, a new stable diradical was obtained, and this was characterized using ESR, IR, and UV-Vis. This process demonstrates that the well-known chemistry based on DPPH can be extended to DPPH-diradical. Full article

Polyethersulfone (PES) is one of the most used synthetic polymers for the production of hemodialysis membranes, due to its appropriate features, such as biocompatibility, high permeability for low-molecular-weight proteins, high endotoxin retention ability, and resistance to sterilization processes. However, there is room for improvement regarding their anticoagulant properties when coming into contact with blood. In the present study, commercial PES membranes were plasma-treated and then chemically modified with crown ether, an organic compound that could interfere with the coagulation cascade by complexating Ca²⁺ in the blood. The physico-chemical and morphological characteristics of the membranes were determined by FT-IR, XPS, TGA, SEM, and CT analyses, while their efficiency in retaining calcium ions was evaluated via ICP-MS. The results revealed that plasma treatment with a mixture of argon and ammonia was the most effective in generating nitrogen-containing surface functional groups and that these moieties can be successfully used for the covalent functionalization of the membranes. Also, the Ca²⁺ retention ability of the PES membranes was improved by up to 30% after chemical modification with 4′-aminobenzo-15-crown-5 ether. Full article

We hypothesized that compounds containing ether linkages within their backbone structures, when exposed to hydroxyl radicals (•OH), can generate ultra-weak photon emission (UPE) as a result of the formation of triplet excited carbonyl species (³R=O*). To evaluate this hypothesis, we investigated the UPE of four compounds, each at a final concentration of 185.2 µmol/L: EGTA (ethylene glycol-bis(β-aminoethyl ether)-N,N,N′,N′-tetraacetic acid), a potent chelator of divalent cations, and three crown ethers—12-crown-4, 15-crown-5, and 18-crown-6—containing two, four, five, and six ether bonds, respectively. •OH was generated using a modified Fenton reagent—92.6 µmol/L Fe²⁺ and 2.6 mmol/L H₂O₂. The highest UPE was recorded for the Fe²⁺–EGTA–H₂O₂ (2863 ± 158 RLU; relative light units), followed by 18-crown-6, 15-crown-5, and 12-crown-4 (1161 ± 78, 615± 86, and 579 ± 109 RLU, respectively; p < 0.05), corresponding to the number of ether groups present. Controls lacking either H₂O₂ or Fe²⁺ exhibited no significant light emission compared to the buffer medium. These findings support the hypothesis that ether bonds, when oxidatively attacked by •OH, undergo chemical transformations resulting in the formation of ³R=O* species, the decay of which is associated with UPE. In crown ethers exposed to Fe²⁺-H₂O₂, the intensity of UPE was correlated with the number of ether bonds in their structure. Full article