Activity of foliar extracts of cultivated eggplants against sclerotinia lettuce drop disease and their phytochemical profiles

Antifungal activity of plant-derived compounds can be exploited in disease management systems to improve sustainability and replace synthetic molecules. In this study, four crude hydroethanolic extracts of leaves, collected from Italian Solanum spp. landraces, were selected to evaluate their ability to suppress Sclerotinia minor Jagger, a great threat to lettuce production worldwide. In vitro fungal development was inhibited by Solanum melongena L. and S. aethiopicum L. extracts showing a dose-dependent correlation. At the highest concentration tested in the current experiments (45 mg mL^?1) antifungal activity caused up to 90% growth reduction. The exposure of the fungus to S. aethiopicum extracts incited pronounced changes in the hyphal morphology as observed under light microscopy. Consistently, under laboratory conditions, in planta application of the active extracts on lettuce significantly reduced Sclerotinia drop disease in comparison to non-treated controls. Phytochemical composition was determined by liquid chromatography/mass spectrometry (LC/MS) analyses. Four secondary metabolites differentially present in the extracts, identified as n-caffeoylputrescine, chlorogenic acid, isoquercitrin and solasodoside A, are hypothesized to play a crucial role in mechanisms underlying biological effects of extracts. PCA analysis showed positive correlations of these compounds with the overall control ability of the extracts. The results indicated that foliar material from cultivated eggplant could be suitable to produce biological-based remedies for controlling plant diseases.     

Effects of nitrogen application rate on productivity,nutritive value and winter tolerance of timothy and meadow fescue cultivars

Finnish N fertilizer application regulations for forage grasses are based on field experiments mainly conducted in the 1960–1970s with cultivars and management practices typical of the time. In order to update the yield response function of N, to make it better suited to current grassland farming, field experiments were conducted at two sites in 2015–2017 with two cultivars of timothy (Phleum pratense L.) and one of meadow fescue (Festuca pratensis Huds.). Dry matter (DM) yield, nutritive value and N balance were evaluated, with N application levels 0, 150, 200, 250, 300, 350, 400 and 450 kg N ha⁻¹ year⁻¹. The grasses were harvested three times per season. The data indicate that the DM yield response was significantly stronger, and N was used more efficiently for DM production than earlier without compromising the nutritive value, especially during the first two years. The third harvest produced on average 23% of the annual yield, utilizing N efficiently. N application rates below 350 kg N ha⁻¹ year⁻¹ did not cause substantial overwintering losses or lodging. The data indicate that with changing climate and improved cultivars and management practices, there is a need to modify the rates and timing of N application. The results suggest that N application levels could be increased by at least 50 kg N ha⁻¹ year⁻¹ from the current maximum accepted rate (250 kg N ha⁻¹ year⁻¹) without too high NO₃^- or CP concentrations in feed, or too high N balance that indicates increasing risk of N leaching.     

Antioxidant properties and composition of aqueous extracts from Mentha species, hybrids, varieties, and cultivars

Water-soluble extracts from the Mentha species M. aquatica L. and M. haplocalyx Briq., the hybrids M. x dalmatica L. and M. x verticillata L., the varieties M. arvensis var. japanensis [M. arvensis L. var. piperascens Holmes ex Christ] and M. spicata L. var. crispa Benth, and M. x piperita L. "Frantsila", M. "Morocco", and M. "Native Wilmet" cultivars were screened for potential antioxidative properties. These properties included iron(III) reduction, iron(II) chelation, 1,1-diphenyl-2-picrylhydrazyl radical scavenging, and the ability to inhibit iron(III)-ascorbate-catalyzed hydroxyl radical-mediated brain phospholipid peroxidation. Total phenol content and qualitative and quantitative compositional analyses of each extract were also made. The extracts demonstrated varying degrees of efficacy in each assay, with the M. x piperita "Frantsila" extract being better than the other extracts, except for ferrous iron chelation. With the exception of iron chelation, it appeared that the level of activity identified was strongly associated with the phenolic content.     

Effects of planting orientation and density of willows on biomass production and nutrient leaching

Willow buffer strips are a promising vegetated filter for the reduction of non-point source pollution from agricultural land to watercourses resulting from the rapid growth of shoots and from the large amount and distribution of roots. A greenhouse experiment tested the hypothesis that a new planting method, planting cuttings horizontally, exhibited more biomass production and more effective filter than did planting cuttings vertically. Due to the different times taken for shoots break through the soil surface, the summed height of all shoots of horizontally planted cuttings was significantly smaller than that of the vertical ones at the beginning of the growth period. The difference in the height of all of the shoots between planting orientations decreased with time. After 16 weeks growth, the biomass of the stem, leaves and fine roots was not affected by the planting orientation. The coarse root biomass was larger in the horizontal treatments and decreased with increased density. The total biomass, as well as the biomass of stem or leaves, of each treatment, increased with increased planting density. The individual plant biomass, as well as that of the stem or leaves, decreased with increased planting density. Compared with the unplanted control treatment, the planted treatments significantly reduced the total-N, NO₃-N, PO₄-P and SO₄-S leaching. The planting orientation did not affect the nitrate leaching. The horizontally planted cuttings were slightly more effective for reducing the SO₄-S leaching and the vertically planted cuttings were slightly more effective for reducing the PO₄-P leaching. Lower PO₄-P leaching was observed only with higher planting density. With regard to the horizontal planting method, further studies are needed to explore the influence of different willow clones, the size of cuttings, pre-planting treatments, planting geometry (configuration) and soil conditions on survival, the number of shoots produced, the biomass production and the amount and distribution of roots.     

Characterization and estimation of proanthocyanidins and other phenolics in coffee pulp (Coffea arabica) by thiolysis-high-performance liquid chromatography

Fresh and 3-day-old coffee pulp of the Arabica variety were analyzed for polyphenol composition followed by characterization by two different methods. The first method consisted in subjecting coffee pulp powder to direct thiolysis. For the second method, coffee pulp was subjected to successive solvent extractions, followed by thiolysis. Quantification of phenolic compounds was then achieved by high-performance liquid chromatography (HPLC) analysis of thiolysis products. Four major classes of polyphenols were identified: flavan-3-ols (monomers and procyanidins), hydroxycinnamic acids, flavonols, and anthocyanidins. Differences in concentration of procyanidins were observed between fresh and 3-day-old coffee pulp. Constitutive units were mainly epicatechin, representing more than 90% of the proanthocyanidin units, with average degrees of polymerization in the range of 3.8-9.1. Monomer to hexamer units of flavan-3-ols from fresh coffee pulp were separated by normal-phase HPLC. Molecular size of oligomeric proanthocyanidins was obtained by matrix-assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOF MS). Results obtained confirm the presence of oligomers of the flavan-3-ol (-)-epicatechin.     

An open-label, dose-escalating phase I study of elsamitrucin (SPI 28090) in treatment of malignant solid tumors in dogs

Background: Elsamitrucin, the most potent topoisomerase II inhibitor available, is unique in that it does not cause neutropenia or cardiotoxicosis. It has antitumor activity in human patients with relapsed or refractory non‐Hodgkin's lymphoma. Objectives: To determine the maximum tolerated dose (MTD), safety, and toxicity of elsamitrucin when administered to tumor‐bearing dogs and to evaluate the incidence and severity of adverse events. Animals: Twenty client‐owned dogs with spontaneous malignant solid tumors or lymphoma that were refractory to, or for which the owner declined, conventional therapy were enrolled. Methods: Prospective, open‐label, single‐agent study. Escalating doses of elsamitrucin were administered once weekly IV for up to 16 weeks in a modified 3 + 3 Phase I design. The starting dose was 0.06 mg/kg with escalation to 0.08 and 0.09 mg/kg. Dogs that remained on the study were monitored for evidence of toxicoses for at least 4 weeks and for survival every 2 months. Results: Serious adverse events (SAEs) possibly attributable to elsamitrucin include: 1 dog developed heart failure and another developed hepatotoxicosis manifested by increased alanine aminotransferase, alkaline phosphatase, and total bilirubin (0.06 mg/kg dose); 1 dog developed severe anorexia and diarrhea, another developed severe diarrhea alone, and a 3rd dog went into cardiac arrest (0.09 mg/kg dose). A dose of 0.08 mg/kg was well tolerated with no SAEs. Conclusions and Clinical Importance: The MTD and recommended dose for Phase II trials of elsamitrucin is 0.08 mg/kg IV weekly. Elsamitrucin might be considered for combination protocols with myelosuppressive chemotherapy agents.