Novel cinnamic acid derivatives as a versatile tool for developing agrochemicals for controlling plant virus and bacterial diseases by enhancing plant defense responses.

BACKGROUND: Plant pathogens have led to large yield and quality losses in crops worldwide. The discovery and study of novel agrochemical alternatives based on the chemical modification of bioactive natural products is a highly efficient approach. Here, two series of novel cinnamic acid derivatives incorporating diverse building blocks with alternative linking patterns were designed and synthesized to identify their antiviral capacity and antibacterial activity. RESULTS: The bioassay results demonstrated that most cinnamic acid derivatives had excellent antiviral competence toward tobacco mosaic virus (TMV) in vivo, especially compound A5 (median effective concentration [EC50 ] = 287.7 µg mL-1 ), which had a notable protective effect against TMV when compared with the commercial virucide ribavirin (EC50  = 622.0 µg mL-1 ). In addition, compound A17 had a protective efficiency of 84.3% at 200 µg mL-1 against Xac in plants. Given these outstanding results, the engineered title compounds could be regarded as promising leads for controlling plant virus and bacterial diseases. Preliminary mechanistic studies suggest that compound A5 could enhance the host's defense responses by increasing the activity of defense enzymes and upregulating defense genes, thereby suppressing phytopathogen invasion. CONCLUSION: This research lays a foundation for the practical application of cinnamic acid derivatives containing diverse building blocks with alternative linking patterns in pesticide exploration. © 2023 Society of Chemical Industry.

The Effects of Post-Acute Care in Patients with Heart Failure in Taiwan: A Single Center Experience.

Background: The National Health Insurance Administration in Taiwan has promoted the heart failure post-acute care (HF-PAC) program as a means to provide proactive integrated care within the optimal treatment timeframe to enhance functional recovery after acute decompensated heart failure (HF). Objectives: The aim of this program was to reduce HF readmission rates, improved medication prescription rates, and improve the quality of life in HF patients. Methods: Patients who had a reduced left ventricular ejection fraction (LVEF) of ≤ 40% were included and followed up for 6 months after discharge. They underwent cardiac rehabilitation and physiological, and nutritional status evaluations. The main clinical outcomes of the HF-PAC program were guideline-directed medical therapy prescription rate and 6-month readmission rate. Results: A total of 122 patients were recruited from June 2018 to December 2020 at a medical center in southern Taiwan. The patients' activities of daily living, nutritional status, quality of life and LVEF were significantly improved during the HF-PAC program. More than 95% of the patients received guideline-directed medical prescriptions at the end of the HF-PAC program. The cardiovascular-related 6-month re-admission rate after the HF-PAC program ended was 27.7%, and it could be predicted by the New York Health Association functional class [hazard ratio (HR) 95% confidence interval (95% CI) = 4.12 (1.36-12.46)], value of the Mini Nutritional Assessment - Short Form [HR (95% CI) = 0.46 (0.31-0.68)] and LVEF [HR (95% CI) = 0.95 (0.91-0.99)]. Conclusions: By incorporating multidisciplinary healthcare teams, the HF-PAC program improves the guideline- directed medical therapy prescription rate, thus improving patients' cardiac function, physical activity recovery, the quality of life, and also reduces their readmission rate.

Resistance-driven innovations in the discovery of bactericides: novel triclosan derivatives decorating isopropanolamine moiety as promising anti-biofilm agents against destructive plant bacterial diseases.

BACKGROUND: Controlling bacterial infections in plants is a major challenge owing to the appearance of resistant strains. As a physical barrier, the bacterial biofilm helps bacterial infections acquire drug resistance by enabling bacteria to accommodate complex and volatile environmental conditions and avoid bactericidal effects. Thus, developing new antibacterial agents with antibiofilm potency is imperative. RESULTS: A series of simple triclosan derivatives containing isopropanolamine moiety were elaborately designed and assessed for their antibacterial behavior. Bioassay results showed that some title compounds had excellent bioactivity against three destructive bacteria Xanthomonas oryzae pv. oryzae (Xoo), Xanthomonas axonopodis pv. citri (Xac) and Pseudomonas syringae pv. actinidiae (Psa). Notably, compound C8 displayed high bioactivities toward Xoo and Xac, with EC50 values were 0.34 and 2.11 µg mL-1 , respectively. In vivo trials revealed that compound C8 exhibited excellent protective activities against rice bacterial blight and citrus bacterial canker at 200 µg mL-1 , with control effectivenesses of 49.57% and 85.60%, respectively. Compound A4 had remarkably inhibitory activity toward Psa, with an EC50 value of 2.63 µg mL-1 , and demonstrated outstanding protective activity with a value of 77.23% against Psa in vivo. Antibacterial mechanisms indicated that compound C8 dose-dependently prevented biofilm formation and extracellular polysaccharide production. C8 also significantly weakened the motility and pathogenicity of Xoo. CONCLUSION: This study contributes to the development and excavation of novel bactericidal candidates with broad-spectrum antibacterial activity by targeting bacterial biofilm to control refractory plant bacterial diseases. © 2023 Society of Chemical Industry.

Novel spiro[chromanone-2,4'-piperidine]-4-one derivatives as potential inhibitors of fatty acid synthesis in pathogens: Design, synthesis, and biological evaluation.

Bacterial survival depends on membrane lipid homeostasis that enables to regulate lipid composition to adapt and optimize their growth in diverse environments. Therefore, the development of inhibitors that interfere with the bacterial fatty acid synthesis process is considered to be a promising tactic. In this study, 58 novel spirochromanone derivatives were prepared and their structure-activity relationship (SAR) was investigated. The bioassay results showed that all most of the compounds showed excellent biological activities, exampled by compounds B14, C1, B15, and B13, which had outstanding inhibitory activities toward various pathogenic bacteria with EC50 values of 0.78 µg/mL ∼3.48 µg/mL. Preliminary antibacterial behavior was studied by a series of biochemical assays including, but not limited to, fluorescence imaging patterns, GC-MS analysis, TEM images, and fluorescence titration experiments. Notably, compound B14 decreased the lipid content of the cell membrane, and increased cell membrane permeability, thereby destroying the integrity of the bacterial cell membrane. Further qRT-PCR results indicated that compound B14 interfered with the mRNA expression levels of fatty acid synthesis process-related genes including ACC, ACP, and Fab family genes. Herein, we highlight the promising bactericidal skeleton based on the spiro[chromanone-2,4'-piperidine]-4-one as a potential inhibitor of fatty acid synthesis.

Discovery of Epipodophyllotoxin-Derived B2 as Promising XooFtsZ Inhibitor for Controlling Bacterial Cell Division: Structure-Based Virtual Screening, Synthesis, and SAR Study.

The emergence of phytopathogenic bacteria resistant to antibacterial agents has rendered previously manageable plant diseases intractable, highlighting the need for safe and environmentally responsible agrochemicals. Inhibition of bacterial cell division by targeting bacterial cell division protein FtsZ has been proposed as a promising strategy for developing novel antibacterial agents. We previously identified 4'-demethylepipodophyllotoxin (DMEP), a naturally occurring substance isolated from the barberry species Dysosma versipellis, as a novel chemical scaffold for the development of inhibitors of FtsZ from the rice blight pathogen Xanthomonas oryzae pv. oryzae (Xoo). Therefore, constructing structure-activity relationship (SAR) studies of DMEP is indispensable for new agrochemical discovery. In this study, we performed a structure-activity relationship (SAR) study of DMEP derivatives as potential XooFtsZ inhibitors through introducing the structure-based virtual screening (SBVS) approach and various biochemical methods. Notably, prepared compound B2, a 4'-acyloxy DMEP analog, had a 50% inhibitory concentration of 159.4 µM for inhibition of recombinant XooFtsZ GTPase, which was lower than that of the parent DMEP (278.0 µM). Compound B2 potently inhibited Xoo growth in vitro (minimum inhibitory concentration 153 mg L-1) and had 54.9% and 48.4% curative and protective control efficiencies against rice blight in vivo. Moreover, compound B2 also showed low toxicity for non-target organisms, including rice plant and mammalian cell. Given these interesting results, we provide a novel strategy to discover and optimize promising bactericidal compounds for the management of plant bacterial diseases.

Surgical outcome of benign cases with pelvic adhesions undergoing robotic total hysterectomy.

BACKGROUND: Robotic total hysterectomies have been considered contraindicated for patients with intra-abdominal adherences, but the evidence for this is not strong, and we hypothesized that the procedure can be of benefit even in these cases. In our research, we analyzed how the severity of pelvic adhesions affects robotic total hysterectomy, and by comparing different types of adhesions, we can further identify the outcomes differences in between, which may aid in future surgical decision making. METHODS: Prospective cohort study (Canadian Task Force classification II-2). All 410 patients with uterine myoma or adenomyosis undergoing robotic total hysterectomies between 2011 and 2016 using the da Vinci Si system by the same surgeon in Taipei Medical University Hospital were included in the study. RESULTS: Baseline characteristics, blood loss, docking time, operation time, time to perform uterine artery ligation (UAL), pain score, hospital stay, complication rate, and laparotomy conversion rate were analyzed between benign cases with or without pelvic adhesions undergoing robotic total hysterectomy. Furthermore, in our subgroups analysis, we have divided the patients with adhesion into different groups according to the severity of adhesion. The abdomen and pelvic cavity was divided into nine sections, and the outcomes of different adhesion condition were compared. We found that patients with adhesions had increased docking time and operation time, but other differences between groups were not statistically significant. The results of the adhesion group showed no significant increases in blood loss, intra- and postoperative complications, and length of hospital stay. Only significantly longer surgical time compared with the normal group was noted. CONCLUSION: Our results suggest that robotic total hysterectomies with UAL are effective and safe for patients with benign gynecologic conditions, and the surgical method should be considered even for patients with adhesion risks.

Cucurbit[7]uril-Mediated Supramolecular Bactericidal Nanoparticles: Their Assembly Process, Controlled Release, and Safe Treatment of Intractable Plant Bacterial Diseases.

A safe, biocompatible, and stimuli-responsive cucurbit[7]uril-mediated supramolecular bactericidal nanoparticle was fabricated by encapsulating a highly bioactive carbazole-decorated imidazolium salt (A1, EC50 = 0.647 µg/mL against phytopathogen Xanthomonas oryzae pv oryzae) into the host cucurbit[7]uril (CB[7]), thereby leading to self-assembled topographies from microsheets (A1) to nanospheroidal architectures (A1@CB[7]). The assembly behaviors were elucidated by acquired single-crystal structures, 1H NMR, ITC, and X-ray powder diffraction experiments. Complex A1@CB[7] displayed lower phytotoxicity and could efficiently switch on its potent antibacterial ability via introducing a simple competitor 1-adamantanamine hydrochloride (AD). In vivo antibacterial trials against rice bacterial blight revealed that A1@CB[7] could relieve the disease symptoms after being triggered by AD and provide a workable control efficiency of 42.6% at 100 µg/mL, which was superior to bismerthiazol (33.4%). These materials can provide a viable platform for fabricating diverse stimuli-responsive supramolecular bactericides for managing bacterial infections with improved safety.

1,3,4-Oxadiazole Derivatives as Plant Activators for Controlling Plant Viral Diseases: Preparation and Assessment of the Effect of Auxiliaries.

Plant viral diseases cause the loss of millions of dollars to agriculture around the world annually. Therefore, the development of highly efficient, ultra-low-dosage agrochemicals is desirable for protecting the health of crops and ensuring food security. Herein, a series of 1,3,4-oxadiazole derivatives bearing an isopropanol amine moiety was prepared, and the inhibitory activity against tobacco mosaic virus (TMV) was assessed. Notably, compound A14 exhibited excellent anti-TMV protective activity with an EC50 value of 137.7 mg L-1, which was superior to that of ribavirin (590.0 mg L-1) and ningnanmycin (248.2 mg L-1). Moreover, the anti-TMV activity of some compounds could be further enhanced (by up to 5-30%) through supplementation with 0.1% auxiliaries. Biochemical assays suggested that compound A14 could suppress the biosynthesis of TMV and induce the plant's defense response. Given these merits, designed compounds had outstanding bioactivities and unusual action mechanisms and were promising candidates for controlling plant viral diseases.

Discovery of novel rost-4-ene derivatives as potential plant activators for preventing phytopathogenic bacterial infection: Design, synthesis and biological studies.

BACKGROUND: Gradually aggravated disease caused by phytopathogenic bacteria severely restricts food security and crop yield, and few pesticides can relieve this severe situation. Thus, development and excavation of new agrochemicals with high bioactivity and novel action mechanism may be a feasible strategy to control intractable bacterial diseases. As a privileged molecular framework, steroid molecules exhibit diversiform bioactivities. Herein, a series of novel androst-4-ene derivatives were designed, synthesised and investigated for their antibacterial behaviour to excavate novel agrochemicals on the base of steroid molecules. RESULTS: Bioassay results indicated that target compounds displayed high bioactivities toward three destructive phytopathogenic bacteria, including Xanthomonas oryzae pv. oryzae (Xoo), Xanthomonas axonopodis pv. citri (Xac) and Pseudomonas syringae pv. actinidiae (Psa). Compound III19 displayed excellent in vitro antibacterial profiling (EC50  = 2.37 mg L-1 towards Xoo, EC50  = 2.10 mg L-1 towards Xac, EC50  = 9.50 mg L-1 towards Psa). Furthermore, compound III19 showed outstanding in vivo protective activities, with values of 81.81% and 58.75% towards kiwifruit bacterial canker and rice bacterial leaf blight, respectively. Analysis of the antibacterial mechanism disclosed that compound III19 enhanced host defence enzyme activities superoxide dismutase (SOD), peroxidase (POD), phenylalanine ammonia lyase (PAL), polyphenol oxidase (PPO), and catalase (CAT) and increased the salicylate synthase content to induce host resistance. In addition, compound III19 increased the membrane permeability, destroyed the cell membrane and killed the bacteria. CONCLUSION: Given these profiles of target compounds, we highlight a new strategy for controlling intractable plant bacterial diseases by inducing plant resistance and targeting the bacterial cell membrane. © 2022 Society of Chemical Industry.

Exploring an Innovative Strategy for Suppressing Bacterial Plant Disease: Excavated Novel Isopropanolamine-Tailored Pterostilbene Derivatives as Potential Antibiofilm Agents.

Bacterial biofilms are the root cause of persistent and chronic phytopathogenic bacterial infections. Therefore, developing novel agrochemicals that target the biofilm of phytopathogenic bacteria has been regarded as an innovative tactic to suppress their invasive infection or decrease bacterial drug resistance. In this study, a series of natural pterostilbene (PTE) derivatives were designed, and their antibacterial potency and antibiofilm ability were assessed. Notably, compound C1 displayed excellent antibacterial potency in vitro, affording an EC50 value of 0.88 µg mL-1 against Xoo (Xanthomonas oryzae pv. oryzae). C1 could significantly reduce biofilm formation and extracellular polysaccharides (EPS). Furthermore, C1 also possessed remarkable inhibitory activity against bacterial extracellular enzymes, pathogenicity, and other virulence factors. Subsequently, pathogenicity experiments were further conducted to verify the above primary outcomes. More importantly, C1 with pesticide additives displayed excellent control efficiency. Given these promising profiles, these pterostilbene derivatives can serve as novel antibiofilm agents to suppress plant pathogenic bacteria.

Design, Synthesis, and Biological Profiles of Novel 1,3,4-Oxadiazole-2-carbohydrazides with Molecular Diversity.

To unceasingly expand the molecular diversity of 1,3,4-oxadiazole-2-carbohydrazides, herein, small fragments (including -CH2-, -OCH2-, and -SCH2-) were incorporated into the target compounds to screen out the potential succinate dehydrogenase inhibitors (SDHIs). The bioassay results showed that the antifungal effects (expressed by EC50) against Sclerotinia sclerotiorum, Botryosphaeria dothidea, Fusarium oxysporum, and Colletotrichun higginsianum could reach 1.29 (10a), 0.63 (8h), 1.50 (10i), and 2.09 (10i) µg/mL, respectively, which were slightly lower than those of carbendazim (EC50 were 0.69, 0.13, 0.55, and 0.80 µg/mL, respectively). Especially, compound 10h was extremely bioactive against Gibberella zeae (G. z.) with an EC50 value of 0.45 µg/mL. This outcome was better than that of fluopyram (3.76 µg/mL) and was similar to prochloraz (0.47 µg/mL). In vivo trials against the corn scab (infected by G. z.) showed that compound 10h had control activity of 86.8% at 200 µg/mL, which was better than that of boscalid (79.6%). Further investigations found that compound 10h could inhibit the enzymatic activity of SDH in the G. z. strain with an IC50 value of 3.67 µM, indicating that potential SDHIs might be developed. Additionally, the other biological activities of these molecules were screened simultaneously. The anti-oomycete activity toward Phytophthora infestans afforded a minimal EC50 value of 3.22 µg/mL (10h); compound 4d could strongly suppress the growth of bacterial strains Xanthomonas axonopodis pv. citri and Xanthomonas oryzae pv. oryzae with EC50 values of 3.79 and 11.4 µg/mL, respectively; and compound 10a displayed some insecticidal activity toward Plutella xylostella. Given their multipurpose features, these frameworks could be actively studied as potential pesticide leads.

Fabrication of Host-Guest Complexes between Adamantane-Functionalized 1,3,4-Oxadiazoles and ß-Cyclodextrin with Improved Control Efficiency against Intractable Plant Bacterial Diseases.

Supramolecular chemistry provides huge potentials and opportunities in agricultural pest management. In an attempt to develop highly bioactive, eco-friendly, and biocompatible supramolecular complexes for managing intractable plant bacterial diseases, herein, a type of interesting adamantane-functionalized 1,3,4-oxadiazole was rationally prepared to facilitate the formation of supramolecular complexes via ß-cyclodextrin-adamantane host-guest interactions. Initial antibacterial screening revealed that most of these adamantane-decorated 1,3,4-oxadiazoles were obviously bioactive against three typically destructive phytopathogens. The lowest EC50 values could reach 0.936 (III18), 0.889 (III18), and 2.10 (III19) µg/mL against the corresponding Xanthomonas oryzae pv. oryzae (Xoo), Xanthomonas axonopodis pv. citri (Xac), and Pseudomonas syringae pv. actinidiae (Psa). Next, the representative supramolecular binary complex III18@ß-CD (binding mode 1:1) was successfully fabricated and characterized by 1H nuclear magnetic resonance (NMR), isothermal titration calorimetry (ITC), high-resolution mass spectrometry (HRMS), dynamic light scattering (DLS), and transmission electron microscopy (TEM). Eventually, correlative water solubility and foliar surface wettability were significantly improved after the formation of host-guest assemblies. In vivo antibacterial evaluation found that the achieved supramolecular complex could distinctly alleviate the disease symptoms and promote the control efficiencies against rice bacterial blight (from 34.6-35.7% (III18) to 40.3-43.6% (III18@ß-CD)) and kiwi canker diseases (from 41.0-42.3% (III18) to 53.9-68.0% (III18@ß-CD)) at 200 µg/mL (active ingredient). The current study can provide a feasible platform and insight for constructing biocompatible supramolecular assemblies for managing destructive bacterial infections in agriculture.

Synthesis and Biological Evaluation of 1,2,4-Triazole Thioethers as Both Potential Virulence Factor Inhibitors against Plant Bacterial Diseases and Agricultural Antiviral Agents against Tobacco Mosaic Virus Infections.

Targeting the virulence factors of phytopathogenic bacteria is an innovative strategy for alleviating or eliminating the pathogenicity and rapid outbreak of plant microbial diseases. Therefore, several types of 1,2,4-triazole thioethers bearing an amide linkage were prepared and screened to develop virulence factor inhibitors. Besides, the 1,2,4-triazole scaffold was exchanged by a versatile 1,3,4-oxadiazole core to expand molecular diversity. Bioassay results revealed that a 1,2,4-triazole thioether A10 bearing a privileged N-(3-nitrophenyl)acetamide fragment was extremely bioactive against Xanthomonas oryzae pv. oryzae (Xoo) with an EC50 value of 5.01 µg/mL. Label-free quantitative proteomics found that compound A10 could significantly downregulate the expression of Xoo's type III secretion system (T3SS) and transcription activator-like effector (TALE) correlative proteins. Meanwhile, qRT-PCR detection revealed that the corresponding gene transcription levels of these virulence factor-associated proteins were substantially inhibited after being triggered by compound A10. As a result, the hypersensitive response and pathogenicity were strongly depressed, indicating that a novel virulence factor inhibitor (A10) was probably discovered. In vivo anti-Xoo trials displayed that compound A10 yielded practicable control efficiency (54.2-59.6%), which was superior to thiadiazole-copper and bismerthiazol (38.1-44.9%). Additionally, compound A10 showed an appreciable antiviral activity toward tobacco mosaic virus (TMV) with the curative and protective activities of 54.6 and 76.4%, respectively, which were comparable to ningnanmycin (55.2 and 60.9%). This effect was further validated and visualized by the inoculation test using GFP-labeled TMV, thereby leading to the reduced biosynthesis of green-fluorescent TMV on Nicotiana benthamiana. Given the outstanding features of compound A10, it should be deeply developed as a versatile agricultural chemical.

Fabrication of Versatile Pyrazole Hydrazide Derivatives Bearing a 1,3,4-Oxadiazole Core as Multipurpose Agricultural Chemicals against Plant Fungal, Oomycete, and Bacterial Diseases.

Developing multipurpose agricultural chemicals is appealing in crop protection, thus eventually realizing the reduction and efficient usage of pesticides. Herein, an array of versatile pyrazole hydrazide derivatives bearing a 1,3,4-oxadiazole core were initially synthesized and biologically evaluated the antifungal, antioomycetes, and antibacterial activities. In addition, the pyrazole ring was replaced by the correlative pyrrole, thiazole, and indole scaffolds to extend the molecular diversity. The results showed that most of these hybrid compounds were empowered with multifunctional bioactivities, which are exemplified by compounds a1-a6, b1-b3, b7, b10, b13, and b18. For the antifungal activity, the minimal EC50 values could afford 0.47 (a2), 1.05 (a2), 0.65 (a1), and 1.32 µg/mL (b3) against the corresponding fungi Gibberella zeae (G. z.), Fusarium oxysporum, Botryosphaeria dothidea, and Rhizoctonia solani. In vivo pot experiments against corn scab (caused by G. z.) revealed that the compound a2 was effective with protective and curative activities of 90.2 and 86.3% at 200 µg/mL, which was comparable to those of fungicides boscalid and fluopyram. Further molecular docking study and enzymatic activity analysis (IC50 = 3.21 µM, a2) indicated that target compounds were promising succinate dehydrogenase inhibitors. Additionally, compounds b2 and a4 yielded superior anti-oomycete and antibacterial activities toward Phytophora infestins and Xanthomonas oryzae pv. oryzae with EC50 values of 2.92 and 8.43 µg/mL, respectively. In vivo trials against rice bacterial blight provided the control efficiency within 51.2-55.3% (a4) at 200 µg/mL, which were better than that of bismerthiazol. Given their multipurpose characteristics, these structures should be positively explored as agricultural chemicals.

Rational Optimization of 1,2,3-Triazole-Tailored Carbazoles As Prospective Antibacterial Alternatives with Significant In Vivo Control Efficiency and Unique Mode of Action.

Plant bacterial diseases can potentially damage agricultural products around the world, and few effective bactericides can manage these infections. Herein, to sequentially explore highly effective antibacterial alternatives, 1,2,3-triazole-tailored carbazoles were rationally fabricated. These compounds could suppress the growth of three main intractable pathogens including Xanthomonas oryzae pv oryzae (Xoo), X. axonopodis pv citri (Xac), and Pseudomonas syringae pv actinidiae (Psa) with lower EC50 values of 3.36 (3p), 2.87 (3p), and 4.57 µg/mL (3r), respectively. Pot experiments revealed that compound 3p could control the rice bacterial blight with protective and curative efficiencies of 53.23% and 50.78% at 200 µg/mL, respectively. Interestingly, the addition of 0.1% auxiliaries such as organic silicon and orange oil could significantly enhance the surface wettability of compound 3p toward rice leaves, resulting in improved control effectiveness of 65.50% and 61.38%, respectively. Meanwhile, compound 3r could clearly reduce the white pyogenic exudates triggered by Psa infection and afforded excellent control efficiencies of 79.42% (protective activity) and 78.74% (curative activity) at 200 µg/mL, which were quite better than those of commercial pesticide thiodiazole copper. Additionally, a plausible apoptosis mechanism for the antibacterial behavior of target compounds was proposed by flow cytometry, reactive oxygen species detection, and defensive enzyme (e.g., catalase and superoxide dismutase) activity assays. The current work can promote the development of 1,2,3-triazole-tailored carbazoles as prospective antibacterial alternatives bearing an intriguing mode of action.

Antibacterial Functions and Proposed Modes of Action of Novel 1,2,3,4-Tetrahydro-ß-carboline Derivatives that Possess an Attractive 1,3-Diaminopropan-2-ol Pattern against Rice Bacterial Blight, Kiwifruit Bacterial Canker, and Citrus Bacterial Canker.

In recent years, naturally occurring tetrahydro-ß-carboline (THC) alkaloids and their derivatives have been of biological interest. However, few studies and developments have reported the use of such structures in managing plant bacterial diseases. Herein, an array of novel THC derivatives containing an attractive 1,3-diaminopropan-2-ol pattern were prepared to evaluate the antiphytopathogen activity in vitro and in vivo and explore innovative antibacterial frameworks. Notably, target compounds exhibited excellent activities against three rebellious phytopathogens, namely, Pseudomonas syringae pv. actinidiae (Psa), Xanthomonas axonopodis pv. citri, and Xanthomonas oryzae pv. oryzae, at related optimal EC50 values of 2.39 (II9), 2.06 (I23), and 1.69 (II9) µg/mL, respectively. These effects were superior to those of the parent structure 1,2,3,4-THC and positive controls. In vivo assays showed that II9 exhibited excellent control efficiencies of 51.89 and 65.45% at 200 µg/mL against rice bacterial blight and kiwifruit bacterial canker, respectively, and I23 substantially relieved the citrus canker on the leaves. Antibacterial mechanisms indicated that these THC compounds could induce the increment of reactive oxygen species and subsequently endow the tested bacteria with distinct apoptotic behavior. In addition, II9 could alleviate the hypersensitive response and pathogenicity of Psa. Overall, these simple THC derivatives can be further developed as versatile antibacterial agents.

Switching of C-C and C-N Coupling/Cleavage for Hypersensitive Detection of Cu2+ by a Catalytically Mediated 2-Aminoimidazolyl-Tailored Six-Membered Rhodamine Probe.

A robust six-membered rhodamine spirocyclic probe 1 containing a versatile 2-aminoimidazolyl moiety was elaborately designed and synthesized via an attractive C-C and C-N coupling strategy to improve the performance in the detection of ultralow transition metal ions. Probe 1 allowed the highly hypersensitive detection of Cu2+ with a superior picomolar limit of detection (35 pM) and nanomolar naked-eye performance (80 nM) via the switching of C-C and C-N cleavage by a catalytic hydrolysis mode.

Synthesis and Docking Study of N-(Cinnamoyl)-N'-(substituted)acryloyl Hydrazide Derivatives Containing Pyridinium Moieties as a Novel Class of Filamentous Temperature-Sensitive Protein Z Inhibitors against the Intractable Xanthomonas oryzae pv. oryzae Infections in Rice.

Xanthomonas oryzae pv. oryzae (Xoo) is an offensive phytopathogen that can invade a wide range of plant hosts to develop bacterial diseases, including the well-known rice bacterial leaf blight. However, few agrochemicals have been identified to effectively prevent and eliminate Xoo-induced diseases. Thus, designing novel antibacterial compounds on the basis of the potential targets from Xoo may lead to the discovery of highly efficient and innovative anti-Xoo agents. Filamentous temperature-sensitive protein Z (FtsZ), an important functional protein in the progression of cell division, has been widely reported and exploited as a target for creating antibacterial drugs in the field of medicine. Therefore, the fabrication of innovative frameworks targeting XooFtsZ may be an effective method for managing bacterial leaf blight diseases via blocking the binary division and reproduction of Xoo. As such, a series of novel N-(cinnamoyl)-N'-(substituted)acryloyl hydrazide derivatives containing pyridinium moieties were designed, and the anti-Xoo activity was determined. The bioassay results showed that compound A7 had excellent anti-Xoo activity (EC50 = 0.99 mg L-1) in vitro and distinct curative activity (63.2% at 200 mg L-1) in vivo. Further studies revealed that these designed compounds were XooFtsZ inhibitors, validating by the reduced GTPase activity of recombinant XooFtsZ, the nonfilamentous XooFtsZ assembly observed in the TEM images, and the prolonged Xoo cells from the fluorescence patterns. Computational docking studies showed that compound A7 had strong interactions with ASN34, GLN193, and GLN197 residues located in the α helix regions of XooFtsZ. The present study demonstrates the developed FtsZ inhibitors can serve as agents to control Xoo-induced infections.

Curcumin-Cu(II) Ensemble-Based Fluorescence "Turn-On" Mode Sensing the Plant Defensive Hormone Salicylic Acid In Situ and In Vivo.

Salicylic acid (SA), a crucial, plant-derived signal molecule, is capable of launching global transcriptional reprogramming to assist plants in obtaining the systemic acquired resistance (SAR) mechanism. Thus, the accurate detection of SA will not only significantly contribute to the understanding of the plant SAR but also contribute to crop protection and to the security of the agricultural production and food supply. However, detection of SA using fluorescent probes is a great challenge for scientists, because SA analogues can significantly interfere with the detection results. Herein, we first reported using a simple, natural curcumin-Cu2+ ensemble to selectively and sensitively monitor SA in situ and in vivo, directed by a fluorescence "turn-on" mode. A binary combination curcumin-Cu2+ was first fabricated with a fluorescence "turn-off" pattern caused by the paramagnetic nature of Cu2+. Subsequently, a fluorescence "turn-on" response was performed for detecting SA accompanied by the formation of the ternary complex curcumin-Cu2+-SA due to the high affinity of SA toward Cu2+, which reduced the fluorescent impact caused by the paramagnetism of Cu2+. Further study revealed that the rationally designed hybrid probe could monitor SA in living cell lines. We anticipate that this finding can inspire the discovery of a high-performance SA probe.

Synthesis of novel 18ß-glycyrrhetinic piperazine amides displaying significant in vitro and in vivo antibacterial activities against intractable plant bacterial diseases.

BACKGROUND: The limited amount of agrochemicals targeting plant bacterial diseases has motivated us to study innovative antibacterial surrogates with fresh modes of action. Notably, fabrication of violent apoptosis inducers to control the reproduction of pathogenic bacteria should be a feasible way to control plant bacterial diseases. To achieve this aim, we constructed a series of novel 18ß-glycyrrhetinic piperazine amides based on the natural bioactive ingredient 18ß-glycyrrhetinic acid to evaluate the in vitro and in vivo antibacterial activity and induced apoptosis behaviors on tested pathogens. RESULTS: Screening results suggested that these designed compounds were extremely bioactive against two notorious pathogens, Xanthomonas oryzae pv. oryzae and X. axonopodis pv. citri. This conclusion was highlighted by the biological effects of compounds A3 and B1 , affording the related EC50 values of 2.28 and 0.93 µg mL-1 . In vivo trials confirmed the prospective application for managing rice bacterial blight disease with control efficiency within 50.57-53.70% at 200 µg mL-1 . In particular, target compounds could induce the generation of excessive reactive oxygen species (ROS) in tested pathogens, subsequently leading to a strong apoptotic effect at a very low drug concentration (≤ 10 µg mL-1 ). This finding was consistent with the observed ROS-enhanced fluorescent images and morphological changes of pathogens from scanning electron microscopy patterns. CONCLUSION: Given these features, we anticipate that these novel piperazine-tailored 18ß-glycyrrhetinic hybrids can provide an perceptible insight for fighting bacterial infections by activation of the apoptosis mechanism. Novel 18ß-glycyrrhetinic piperazine amides were reported to have excellent antibacterial efficacy toward phytopathogens Xanthomonas oryzae pv. oryzae and X. axonopodis pv. citri. A possible apoptosis mechanism was proposed from the remarkable apoptotic behaviors triggered by target compounds. © 2020 Society of Chemical Industry.