DcERF109 regulates shoot branching by participating in strigolactone signal transduction in Dendrobium catenatum.

Shoot branching fundamentally influences plant architecture and agricultural yield. However, research on shoot branching in Dendrobium catenatum, an endangered medicinal plant in China, remains limited. In this study, we identified a transcription factor DcERF109 as a key player in shoot branching by regulating the expression of strigolactone (SL) receptors DWARF 14 (D14)/ DECREASED APICAL DOMINANCE 2 (DAD2). The treatment of D. catenatum seedlings with GR24rac/TIS108 revealed that SL can significantly repress the shoot branching in D. catenatum. The expression of DcERF109 in multi-branched seedlings is significantly higher than that of single-branched seedlings. Ectopic expression in Arabidopsis thaliana demonstrated that overexpression of DcERF109 resulted in significant shoot branches increasing and dwarfing. Molecular and biochemical assays demonstrated that DcERF109 can directly bind to the promoters of AtD14 and DcDAD2.2 to inhibit their expression, thereby positively regulating shoot branching. Inhibition of DcERF109 by virus-induced gene silencing (VIGS) resulted in decreased shoot branching and improved DcDAD2.2 expression. Moreover, overexpression of DpERF109 in A. thaliana, the homologous gene of DcERF109 in Dendrobium primulinum, showed similar phenotypes to DcERF109 in shoot branch and plant height. Collectively, these findings shed new insights into the regulation of plant shoot branching and provide a theoretical basis for improving the yield of D. catenatum.

From UK-2A to florylpicoxamid: Active learning to identify a mimic of a macrocyclic natural product.

Scaffold replacement as part of an optimization process that requires maintenance of potency, desirable biodistribution, metabolic stability, and considerations of synthesis at very large scale is a complex challenge. Here, we consider a set of over 1000 time-stamped compounds, beginning with a macrocyclic natural-product lead and ending with a broad-spectrum crop anti-fungal. We demonstrate the application of the QuanSA 3D-QSAR method employing an active learning procedure that combines two types of molecular selection. The first identifies compounds predicted to be most active of those most likely to be well-covered by the model. The second identifies compounds predicted to be most informative based on exhibiting low predicted activity but showing high 3D similarity to a highly active nearest-neighbor training molecule. Beginning with just 100 compounds, using a deterministic and automatic procedure, five rounds of 20-compound selection and model refinement identifies the binding metabolic form of florylpicoxamid. We show how iterative refinement broadens the domain of applicability of the successive models while also enhancing predictive accuracy. We also demonstrate how a simple method requiring very sparse data can be used to generate relevant ideas for synthetic candidates.

Design, Synthesis and Biological Evaluation of Novel Phenyl-Substituted Naphthoic Acid Ethyl Ester Derivatives as Strigolactone Receptor Inhibitor.

Strigolactones (SLs) are plant hormones that regulate several key agronomic traits, including shoot branching, leaf senescence, and stress tolerance. The artificial regulation of SL biosynthesis and signaling has been considered as a potent strategy in regulating plant architecture and combatting the infection of parasitic weeds to help improve crop yield. DL1b is a previously reported SL receptor inhibitor molecule that significantly promotes shoot branching. Here, we synthesized 18 novel compounds based on the structure of DL1b. We performed rice tillering activity assay and selected a novel small molecule, C6, as a candidate SL receptor inhibitor. In vitro bioassays demonstrated that C6 possesses various regulatory functions as an SL inhibitor, including inhibiting germination of the root parasitic seeds Phelipanche aegyptiaca, delaying leaf senescence and promoting hypocotyl elongation of Arabidopsis. ITC analysis and molecular docking experiments further confirmed that C6 can interact with SL receptor proteins, thereby interfering with the binding of SL to its receptor. Therefore, C6 is considered a novel SL receptor inhibitor with potential applications in plant architecture control and prevention of root parasitic weed infestation.

Legume milk-based yogurt mimetics structured using glucono-δ-lactone.

The potential to produce protein-structured vegan yogurts with legumes was explored to offer an alternative to conventional polysaccharide-based varieties. Glucono-δ-lactone (GDL) was employed as a slow acidifying agent and was investigated for its ability to generate cold-set, yogurt-like gels using soy and lentil milks made using minimal processing steps. Soy (5.3 % protein) and lentil (6.1 % protein) milks were successfully gelled by GDL at concentrations of 0.5 % and 1 % w/w. Soy and lentil milks experienced similar acidification profiles and demonstrated good fits with double-exponential decay models. The physical properties of these legume gels were evaluated and compared to a commercial stirred dairy yogurt. Penetration tests were carried out on intact gels, then repeated after stirring. All intact soy samples demonstrated significantly stronger gel structures compared to the commercial yogurt, and most experienced greater amounts of brittleness. Results showed that the stirring of gels caused a notable decrease in firmness and brittleness in the soy gels, making them more similar to the control. Power-law modelling of viscosity curves demonstrated that all samples experienced non-Newtonian flow behavior (n < 0.29). Susceptibility to syneresis was measured by the degree of liquid loss following centrifugation. The optimization of protein type and GDL concentration to replicate the physical properties of dairy-based yogurts can enhance their consumer acceptance and provide a more customizable and controlled approach alternative to traditional fermentation methods.

The trilogy of human musk receptors: linking receptor activation, genotype, and sensory perception.

The scent of musk plays a unique role in the history of perfumery. Musk odorants comprise 6 diverse chemical classes and perception differences in strength and quality among human panelists have long puzzled the field of olfaction research. Three odorant receptors (OR) had recently been described for musk odorants: OR5AN1, OR1N2, and OR5A2. High functional expression of the difficult-to-express human OR5A2 was achieved by a modification of the C-terminal domain and the link between sensory perception and receptor activation for the trilogy of these receptors and their key genetic variants was investigated: All 3 receptors detect only musky smelling compounds among 440 commercial fragrance compounds. OR5A2 is the key receptor for the classes of polycyclic and linear musks and for most macrocylic lactones. A single P172L substitution reduces the sensitivity of OR5A2 by around 50-fold. In parallel, human panelists homozygous for this mutation have around 40-60-fold higher sensory detection threshold for selective OR5A2 ligands. For macrocyclic lactones, OR5A2 could further be proven as the key OR by a strong correlation between in vitro activation and the sensory detection threshold in vivo. OR5AN1 is the dominant receptor for the perception of macrocyclic ketones such as muscone and some nitromusks, as panelists with a mutant OR5A2 are still equally sensitive to these ligands. Finally, OR1N2 appears to be an additional receptor involved in the perception of the natural (E)-ambrettolide. This study for the first time links OR activation to sensory perception and genetic polymorphisms for this unique class of odorants.

Correlations among different platelet aggregation pathways in a group of healthy volunteers.

Platelet aggregation is a complicated process mediated by different signaling pathways. As the process is highly complex and apparently redundant, the relationships between these pathways are not yet fully known. The aim of this project was to study the interconnections among seven different aggregation pathways in a group of 53 generally healthy volunteers aged 20 to 66 years. Platelet aggregation was induced with thrombin receptor activating peptide 6 (TRAP), arachidonic acid (AA), platelet activating factor 16 (PAF), ADP, collagen, thromboxane A2 analogue U46619 or ristocetin (platelet agglutination) ex vivo in fasting blood samples according to standardized timetable protocol. Additionally, some samples were pre-treated with known clinically used antiplatelet drugs (vorapaxar, ticagrelor or acetylsalicylic acid (ASA)). Significant correlations among all used inducers were detected (Pearson correlation coefficients (rP): 0.3 to 0.85). Of all the triggers, AA showed to be the best predictor of the response to other inducers with rP ranging from 0.66 to 0.85. Interestingly, the antiplatelet response to ticagrelor strongly predicted the response to unrelated drug vorapaxar (rP = 0.71). Our results indicate that a response to one inducer can predict the response for other triggers or even to an antiplatelet drug. These data are useful for future testing but should be also confirmed in patients.

What is the context?• Platelet activation is a complicated process with multiple signaling cascades involved.• A total of seven common platelet triggers (ADP, collagen, TRAP-6, PAF, arachidonic acid/AA/, ristocetin and U46619) were tested.• The process is dependent on many factors including sex, age, concomitant disease(s), pharmacotherapy.What is new?• There were significant correlations between all tested aggregatory cascades.• AA has the highest rate of response predictability in our heterogeneous generally healthy volunteer group.• There was no correlation between impedance aggregometry in whole blood and turbidimetric measurement with platelet-rich plasma.What is the impact?• The effect of antiplatelet drugs can be assessed from the reaction to different trigger(s) at least in this group of healthy patients.• Future studies must test these relationships in patients with different diseases.

Reaction Pattern and Mechanistic Aspects of Iodine and Iodine-Based Reagents in Selenylation of Aliphatic, Aromatic, and (Hetero)Cyclic Systems.

Organoselenium compounds have been the subject of extensive research since the discovery of the biologically active compound ebselen. Ebselen has recently been found to show activity against the main protease of the virus responsible for COVID-19. Other organoselenium compounds are also well-known for their diverse biological activities, with such compounds exhibiting interesting physical properties relevant to the fields of electronics, materials, and polymer chemistry. In addition, the incorporation of selenium into various organic molecules has garnered significant attention due to the potential of selenium to enhance the biological activity of these molecules, particularly in conjunction with bioactive heterocycles. Iodine and iodine-based reagents play a prominent role in the synthesis of organoselenium compounds, being valued for their cost-effectiveness, non-toxicity, and ease of handling. These reagents efficiently selenylate a broad range of organic substrates, encompassing alkenes, alkynes, and cyclic, aromatic, and heterocyclic molecules. They serve as catalysts, additives, inducers, and oxidizing agents, facilitating the introduction of different functional groups at alternate positions in the molecules, thereby allowing for regioselective and stereoselective approaches. Specific iodine reagents and their combinations can be tailored to follow the desired reaction pathways. Here, we present a comprehensive review of the progress in the selenylation of organic molecules using iodine reagents over the past decade, with a focus on reaction patterns, solvent effects, heating, microwave, and ultrasonic conditions. Detailed discussions on mechanistic aspects, such as electrophilic, nucleophilic, radical, electrochemical, and ring expansion reactions via selenylation, multiselenylation, and difunctionalization, are included. The review also highlights the formation of various cyclic, heterocyclic, and heteroarenes resulting from the in situ generation of selenium intermediates, encompassing cyclic ketones, cyclic ethers, cyclic lactones, selenophenes, chromones, pyrazolines, pyrrolidines, piperidines, indolines, oxazolines, isooxazolines, lactones, dihydrofurans, and isoxazolidines. To enhance the reader's interest, the review is structured into different sections covering the selenylation of aliphatic sp2/sp carbon and cyclic sp2 carbon, and then is further subdivided into various heterocyclic molecules.

Global changes in gene expression during compatible and incompatible interactions of faba bean (Vicia faba L.) during Orobanche foetida parasitism.

Orobanche foetida Poiret is the main constraint facing faba bean crop in Tunisia. Indeed, in heavily infested fields with this parasitic plant, yield losses may reach 90%, and the recent estimation of the infested area is around 80,000 ha. Identifying genes involved in the Vicia faba/O. foetida interaction is crucial for the development of effective faba bean breeding programs. However, there is currently no available information on the transcriptome of faba bean responding to O. foetida parasitism. In this study, we employed RNA sequencing to explore the global gene expression changes associated with compatible and incompatible V. faba/O. foetida interactions. In this perspective, two faba bean varieties (susceptible and resistant) were examined at the root level across three stages of O. foetida development (Before Germination (BG), After Germination (AG) and Tubercule Stage (TS)). Our analyses presented an exploration of the transcriptomic profile, including comprehensive assessments of differential gene expression and Gene Ontology (GO) enrichment analyses. Specifically, we investigated key pathways revealing the complexity of molecular responses to O. foetida attack. In this study, we detected differential gene expression of pathways associated with secondary metabolites: flavonoids, auxin, thiamine, and jasmonic acid. To enhance our understanding of the global changes in V. faba response to O. foetida, we specifically examined WRKY genes known to play a role in plant host-parasitic plant interactions. Furthermore, considering the pivotal role of parasitic plant seed germination in this interaction, we investigated genes involved in the orobanchol biosynthesis pathway. Interestingly, we detected the gene expression of VuCYP722C homolog, coding for a key enzyme involved in orobanchol biosynthesis, exclusively in the susceptible host. Clearly, this study enriches our understanding of the V. faba/O. foetida interaction, shedding light on the main differences between susceptible and resistant faba bean varieties during O. foetida infestation at the gene expression level.

Efficacy of dietary supplements of Glycyrrhiza glabra (Licorice) and maduramicin alone or in combination with Eimeria tenella infected chicks: A clinical study and molecular docking.

Background: Coccidiosis is one of the most economically significant poultry diseases worldwide, caused by the pathogenic Eimeria species, and is characterized by decreased weight gain (WG) and failure to grow due to malabsorption, low feed conversion rate, bloody diarrhea, and dehydration. Aim: This study investigated the effectiveness of licorice root extract (LRE) in controlling cecal coccidiosis to determine whether its combination with maduramicin could help alleviate the pathological, biochemical, and histopathological effects of cecal coccidiosis in Sasso broiler chicks. Methods: A total of 125 one-day-old Sasso broiler chicks were categorized into five equal groups (n = 25), each consisting of five replicates (n = 5 per replicate). G1-LE received a basal diet supplemented with LRE (3 g/kg); G2-ME received a basal diet containing maduramycin (0.5 g/kg); and G3-LME received a basal diet containing LRE and maduramicin together with the same rates. G4-E (positive control) and G5-N (negative control) received no additives in their feed. Birds in groups (G1-4) were challenged on day 14 of the experiment by orally intercropping a 1 ml suspension of Eimeria tenella sporulated oocysts. Results: Groups of birds fed on LRE and maduramicin separately or together appeared to be in good condition where no deaths or clinical abnormalities were observed, based on the analysis of clinicopathological examination. Compared with the G4-E positive control, the dropping scoring and oocyst shedding of groups G1-LE, G2-ME, and G3-LME along the 10th-day post-challenge (dpc), as well as macroscopic and microscopic lesions scoring at the 7th dpc, was considerably lower. The dual supplementation use of LRE and maduramicin in G3-LME's reduced the harmful effects of coccidian, which appeared only as a mononuclear cellular infiltration and a small number of oocysts invading the intestinal glands. Molecular docking revealed that LRE and maduramicin interacted with E. tenella DNA polymerase, E. tenella apical membrane antigen 1, and microneme protein binding sites resulting in reduced E. tenella replication and invasion. Conclusion: The inclusion of LRE and maduramicin, individually or in combination, in the diet might effectively mitigate the detrimental effects of coccidiosis.

Cytotoxic Cyclolignans Obtained by the Enlargement of the Cyclolignan Skeleton of Podophyllic Aldehyde, a Selective Podophyllotoxin-Derived Cyclolignan.

Podophyllotoxin, a cyclolignan natural product, has been the object of extensive chemomodulation to obtain better chemotherapeutic agents. Among the obtained podophyllotoxin derivatives, podophyllic aldehyde showed very interesting potency and selectivity against several tumoral cell lines, so it became our lead compound for further modifications, as described in this work, oriented toward the enlargement of the cyclolignan skeleton. Thus, modifications performed at the aldehyde function included nucleophilic addition reactions and the incorporation of the aldehyde carbon into several five-membered rings, such as thiazolidinones and benzo-fused azoles. The synthesized derivatives were evaluated against several types of cancer cells, and although some compounds were cytotoxic at the nanomolar range, most of them were less potent and less selective than the parent compound podophyllic aldehyde, with the most potent being those having the lactone ring of podophyllotoxin. In silico ADME evaluation predicted good druggability for most of them. The results indicate that the γ-lactone ring is important for potency, while the α,ß-unsaturated aldehyde is necessary to induce selectivity in these cyclolignans.

Isolation, Identification and Chemical Modification of Bufadienolides from Bufo melanostictus Schneider and Their Cytotoxic Activities against Prostate Cancer Cells.

The traditional Chinese medicine toad venom (Venenum bufonis) has been extensively used to treat various diseases, including cancers, in China and other Southeast Asian countries. The major constituents of toad venom, e.g., bufadienolides and alkaloids, exhibit broad-spectrum pharmacological effects in cancers. Herein, two new bufadienolides (1 and 2), along with eleven known compounds (3-13) were successfully isolated from Bufo melanostictus Schneider. Their structures were elucidated by extensive spectroscopic data and X-ray diffraction analysis. Furthermore, four lactam derivatives were synthesized through the transformation of bufadienolides lactones. The inhibitory effects of these compounds against human prostate cancer cell lines PC-3 and DU145 were evaluated. The outcomes indicated a notable trend, with a substantial subset displaying nanomolar range IC50 values against PC-3 and DU145 cells, underscoring their pronounced cytotoxicity. Moreover, a noteworthy distinction surfaces, wherein lactones consistently outperformed their lactam counterparts, further validating their heightened potency for the treatment of prostate cancer. This study contributes significant preclinical evidence substantiating the therapeutic viability of bufadienolides and toad venom as intervention strategies for prostate cancer.

[Simultaneous determination of seven artemisinin-related compounds in Artemisia annua by UPLC-QQQ-MS/MS].

A variety of compounds in Artemisia annua were simultaneously determined to evaluate the quality of A. annua from multiple perspectives. A method based on ultra-high performance liquid chromatography-triple quadrupole tandem mass spectrometry(UPLC-QQQ-MS/MS) was established for the simultaneous determination of seven compounds: amorpha-4,11-diene, artemisinic aldehyde, dihydroartemisinic acid, artemisinic acid, artemisinin B, artemisitene, and artemisinin, in A. annua. The content of the seven compounds in different tissues(roots, stems, leaves, and lateral branches) of A. annua were compared. The roots, stems, leaves, and lateral branches of four-month-old A. annua were collected and the content of seven artemisinin-related compounds in different tissues was determined. A multi-reaction monitoring(MRM) acquisition mode of UPLC-QQQ-MS/MS was used, with a positive ion mode of atmospheric pressure chemical ion source(APCI). Chromatographic separation was achieved on an Eclipse Plus RRHD C_(18) column(2.1 mm×50 mm, 1.8 µm). The gradient elution was performed with the mobile phase consisted of formic acid(0.1%)-ammonium formate(5 mmol·L~(-1))(A) and the methanol(B) gradient program of 0-8 min, 55%-100% B, 8-11 min, 100% B, and equilibrium for 3 min, the flow rate of 0.6 mL·min~(-1), the column temperature of 40 ℃, the injection volume of 5 µL, and the detection time of 8 min. Through methodological investigation, a method based on UPLC-QQQ-MS/MS was established for the simultaneous quantitative determination of seven representative compounds involved in the biosynthesis of artemisinin. The content of artemisinin in A. annua was higher than that of artemisinin B, and the content of artemisinin and dihydroartemisinic acid were high in all the tissues of A. annua. The content of the seven compounds varied considerably in different tissues, with the highest levels in the leaves and neither artemisinene nor artemisinic aldehyde was detected in the roots. In this study, a quantitative method based on UPLC-QQQ-MS/MS for the simultaneous determination of seven representative compounds involved in the biosynthesis of artemisinin was established, which was accurate, sensitive, and highly efficient, and can be used for determining the content of artemisinin-related compounds in A. annua, breeding new varieties, and controlling the quality of Chinese medicinal materials.

Efficacy of moxidectin, using various dose regimens, against JYD-34, a macrocyclic lactone resistant isolate of Dirofilaria immitis.

BACKGROUND: Macrocyclic lactones (MLs) are the only class of drugs currently commercially available that are effective for preventing heartworm disease. The data presented in this article provide information on the efficacy of oral moxidectin against JYD-34, a known ML-resistant Dirofilaria immitis isolate, when dogs are treated under various dosing regimens. METHODS: Fifty-two purpose-bred Beagle dogs were used in five laboratory studies. All dogs were inoculated with 50 D. immitis third-stage larvae (L3) (JYD-34 isolate) 30 days prior to the first treatment. Dogs were randomized to treatment (four to five animals in each group) with one, three, or five monthly doses of oral moxidectin ranging from 6 to 100 µg/kg body weight. In each study, control dogs were not treated. Five to 6 months after L3 inoculation, dogs were euthanized, and adult worms were counted to evaluate efficacy of the dosing regimens. RESULTS: Adult heartworms were recovered from all control dogs, with an overall geometric mean of 29.7 worms (range 15.2 to 38.0, individual counts ranged from 8 to 51). Five monthly doses of 6 µg/kg provided 83.3% and 90.2%, efficacy, and the same number of monthly doses of 9 µg/kg demonstrated 98.8% and 94.1% efficacy. Three monthly doses of 30 and 50 µg/kg demonstrated 97.9% and 99.0% efficacy, respectively, while a single dose of 100 µg/kg demonstrated 91.1% efficacy. CONCLUSIONS: Five monthly doses of 9 µg/kg provided similar or only marginally lower efficacy against JYD-34, a known ML-resistant isolate, compared to substantially higher doses administered for 3 months. This underscores the importance of duration of exposure to moxidectin when facing ML-resistant isolates. Repeated administration of lower doses of moxidectin are an alternative to higher doses in the prevention of heartworm disease associated with less susceptible or resistant isolates.

Exogenous strigolactone enhanced the drought tolerance of pepper (Capsicum chinense) by mitigating oxidative damage and altering the antioxidant mechanism.

KEY MESSAGE: Exogenous SL positively regulates pepper DS by altering the root morphology, photosynthetic character, antioxidant enzyme activity, stomatal behavior, and SL-related gene expression. Drought stress (DS) has always been a problem for the growth and development of crops, causing significant negative impacts on crop productivity. Strigolactone (SL) is a newly discovered class of plant hormones that are involved in plants' growth and development and environmental stresses. However, the role of SL in response to DS in pepper remains unknown. DS considerably hindered photosynthetic pigments content, damaged root architecture system, and altered antioxidant machinery. In contrast, SL application significantly restored pigment concentration modified root architecture system, and increased relative chlorophyll content (SPAD). Additionally, SL treatment reduced oxidative damage by reducing hydrogen peroxide (H2O2) (24-57%) and malondialdehyde (MDA) (79-89%) accumulation in pepper seedlings. SL-pretreated pepper seedlings showed significant improvement in antioxidant enzyme activity, proline accumulation, and soluble sugar content. Furthermore, SL-related genes (CcSMAX2, CcSMXL6, and CcSMXL3) were down-regulated under DS. These findings suggest that the foliar application of SL can alleviate the adverse effects of drought tolerance by up-regulating chlorophyll content and activating antioxidant defense mechanisms.

[Alternaria toxins in tomato products marketed in the Russian Federation].

Tomatoes and tomato products are widely produced and consumed throughout the world. Alternaria spp. are the main cause of alternariosis (black mold disease) on fresh tomatoes, both in the field and after harvesting. Alternaria toxins are widespread contaminants of tomato products. The aim of the present study was to evaluate the contamination of tomato processing products from the domestic market with Alternaria toxins, as well as to assess their intake by humans through the consumption of tomato juices. Material and methods. The content of Alternaria toxins (alternatiol, alternariol monomethyl ether, altenuene, tentoxin, tenuazonic acid) was determined in 64 samples of tomato products (paste, ketchup, juice) by high-performance liquid chromatography coupled to tandem mass-spectrometric detection (HPLC-MS/MS). Results. The priority Alternaria toxins for tomato paste, ketchup and juice were tenuazonic acid (61% of 64 samples, in amounts from 20.0 to 1065.5 µg/kg), altenuene (52%, 8.9-200.1 µg/kg) and alternariol (27%, 12.2-561.6 µg/kg). Samples of tomato paste turned out to be the most contaminated with Alternaria toxins while tomato juice samples were the least contaminated. At the same time, several toxins were found in 91% of tomato paste samples, 35% of ketchups, and 23% of tomato juices. Conclusion. To the best of our knowledge, the present study is the first survey devoted to Alternaria toxins contamination of tomato paste, ketchup and tomato juice sold on the Russian market. The high frequency of their contamination with tenuazonic acid, altenuene and, to a lesser extent, alternariol has been established, which indicates a potential risk to human health when tomato processing products are consumed. This indicates the need for a hygienic assessment of contamination the above products with tenuazonic acid, altenuene and alternariol. When calculating the potential intake of Alternaria toxins for different age population groups, it was shown that high levels of alternariol (up to 56.77 ng/kg body weight per day) could be obtained under daily consumption of tomato juice by adults and children under three years of age, as well as tenuazonic acid when consuming tomato juice contaminated at the 95th percentile level as part of the diet in organized groups for orphans and children without parental care.

Enzymes with Lactonase Activity against Fungal Quorum Molecules as Effective Antifungals.

Since the growing number of fungi resistant to the fungicides used is becoming a serious threat to human health, animals, and crops, there is a need to find other effective approaches in the eco-friendly suppression of fungal growth. One of the main mechanisms of the development of resistance in fungi, as well as in bacteria, to antimicrobial agents is quorum sensing (QS), in which various lactone-containing compounds participate as signaling molecules. This work aimed to study the effectiveness of action of enzymes exhibiting lactonase activity against fungal signaling molecules. For this, the molecular docking method was used to estimate the interactions between these enzymes and different lactone-containing QS molecules of fungi. The catalytic characteristics of enzymes such as lactonase AiiA, metallo-ß-lactamase NDM-1, and organophosphate hydrolase His6-OPH, selected for wet experiments based on the results of computational modeling, were investigated. QS lactone-containing molecules (butyrolactone I and γ-heptalactone) were involved in the experiments as substrates. Further, the antifungal activity of the enzymes was evaluated against various fungal and yeast cells using bioluminescent ATP-metry. The efficient hydrolysis of γ-heptalactone by all three enzymes and butyrolactone I by His6-OPH was demonstrated for the first time. The high antifungal efficacy of action of AiiA and NDM-1 against most of the tested fungal cells was revealed.

Strigolactones Might Regulate Ovule Development after Fertilization in Xanthoceras sorbifolium.

Strigolactones (SLs) were recently defined as a novel class of plant hormones that act as key regulators of diverse developmental processes and environmental responses. Much research has focused on SL biosynthesis and signaling in roots and shoots, but little is known about whether SLs are produced in early developing seeds and about their roles in ovule development after fertilization. This study revealed that the fertilized ovules and early developing pericarp in Xanthoceras sorbifolium produced minute amounts of two strigolactones: 5-deoxystrigol and strigol. Their content decreased in the plants with the addition of exogenous phosphate (Pi) compared to those without the Pi treatment. The exogenous application of an SL analog (GR24) and a specific inhibitor of SL biosynthesis (TIS108) affected early seed development and fruit set. In the Xanthoceras genome, we identified 69 potential homologs of genes involved in SL biological synthesis and signaling. Using RNA-seq to characterize the expression of these genes in the fertilized ovules, 37 genes were found to express differently in the fertilized ovules that were aborting compared to the normally developing ovules. A transcriptome analysis also revealed that in normally developing ovules after fertilization, 12 potential invertase genes were actively expressed. Hexoses (glucose and fructose) accumulated at high concentrations in normally developing ovules during syncytial endosperm development. In contrast, a low ratio of hexose and sucrose levels was detected in aborting ovules with a high strigolactone content. XsD14 virus-induced gene silencing (VIGS) increased the hexose content in fertilized ovules and induced the proliferation of endosperm free nuclei, thereby promoting early seed development and fruit set. We propose that the crosstalk between sugar and strigolactone signals may be an important part of a system that accurately regulates the abortion of ovules after fertilization. This study is useful for understanding the mechanisms underlying ovule abortion, which will serve as a guide for genetic or chemical approaches to promote seed yield in Xanthoceras.

Three rare anti-inflammatory sesquiterpene lactones from Magnolia grandiflora.

Four new sesquiterpene lactones (SLs) (1-4), along with a biosynthetically related SL (5), have been isolated from the leaves of Magnolia grandiflora. Magrandate A (1) is notable as the first C18 homogemarane type SL, featuring a unique 1,7-dioxaspiro[4.4]nonan-6-one core. Compounds 2 and 3, representing the first instances of chlorine-substituted gemarane-type SL analogs in natural products, were also identified. The structures of these isolates were elucidated through a combination of spectroscopic data analysis, electronic circular dichroism calculations, and X-ray single-crystal diffraction analysis. All isolates demonstrated anti-inflammatory activity in lipopolysaccharide-stimulated RAW264.7 cells. Notably, 3-5 showed a significant inhibitory effect on nitric oxide production, with IC50 values ranging from 0.79 to 4.73 µmol·L-1. Additionally, 4 and 5 exhibited moderate cytotoxic activities against three cancer cell lines, with IC50 values between 3.09 and 11.23 µmol·L-1.

Enantiomeric analysis of γ(δ)-lactones by reversed phase high performance liquid chromatography using amylose tris(5-chloro-2-methylphenylcarbamate) as stationary phase.

A Chiralpak AY-3R column was investigated for analytical enantiomeric separation of twelve racemic γ(δ)-lactones using reversed phase high performance liquid chromatography. Main influence factors, including organic modifier, flow rate and column temperature, were optimized. Five kinds of γ(δ)-lactones were successfully enantioseparated using the established method: γ-nonanolactone, δ-decalactone, δ-undecalactone, δ-dodecalactone and δ-tetradecalactone. Under optimized conditions, enantiomeric peak resolution (Rs) for the five γ(δ)-lactones reached more than 1.09, 1.08, 1.54, 1.43, and 1.11, respectively. Their chromatographic elution behavior was investigated using Van't Hoff equation and Van Deemter equation. It was found that an exothermic process occurred during enantiomeric separation of γ(δ)-lactones using this chromatographic column, and it showed a typical Van Deemter curve. Finally, this method was applied in enantiomeric ratio analysis of γ(δ)-lactones contents for purchased butter samples, and results confirmed the predominant content of the (R)-configuration of δ-dodecalactone in natural animal butter, while in margarine, an equal proportion of (R/S)-configuration of δ-dodecalactone was detected.

SMXL5 attenuates strigolactone signaling in Arabidopsis thaliana by inhibiting SMXL7 degradation.

Hormone-activated proteolysis is a recurring theme of plant hormone signaling mechanisms. In strigolactone signaling, the enzyme receptor DWARF14 (D14) and an F-box protein, MORE AXILLARY GROWTH2 (MAX2), mark SUPPRESSOR OF MAX2 1-LIKE (SMXL) family proteins SMXL6, SMXL7, and SMXL8 for rapid degradation. Removal of these transcriptional corepressors initiates downstream growth responses. The homologous proteins SMXL3, SMXL4, and SMXL5, however, are resistant to MAX2-mediated degradation. We discovered that the smxl4 smxl5 mutant has enhanced responses to strigolactone. SMXL5 attenuates strigolactone signaling by interfering with AtD14-SMXL7 interactions. SMXL5 interacts with AtD14 and SMXL7, providing two possible ways to inhibit SMXL7 degradation. SMXL5 function is partially dependent on an ethylene-responsive-element binding-factor-associated amphiphilic repression (EAR) motif, which typically mediates interactions with the TOPLESS family of transcriptional corepressors. However, we found that loss of the EAR motif reduces SMXL5-SMXL7 interactions and the attenuation of strigolactone signaling by SMXL5. We hypothesize that integration of SMXL5 into heteromeric SMXL complexes reduces the susceptibility of SMXL6/7/8 proteins to strigolactone-activated degradation and that the EAR motif promotes the formation or stability of these complexes. This mechanism may provide a way to spatially or temporally fine-tune strigolactone signaling through the regulation of SMXL5 expression or translation.