Gulypyrones A and B and phomentrioloxins B and C produced by Diaporthe gulyae, a potential mycoherbicide for saffron thistle (Carthamus lanatus)

A virulent strain of Diaporthe gulyae, isolated from stem cankers of sunflower and known to be pathogenic to saffron thistle, has been shown to produce both known and previously undescribed metabolites when grown in either static liquid culture or a bioreactor. Together with phomentrioloxin, a phytotoxic geranylcyclohexenetriol recently isolated from a strain of Phomopsis sp., two new phytotoxic trisubstituted α-pyrones, named gulypyrones A and B (1 and 2), and two new 1,O- and 2,O-dehydro derivatives of phomentrioloxin, named phomentrioloxins B and C (3 and 4), were isolated from the liquid culture filtrates of D. gulyae. These four metabolites were characterized as 6-[(2S)2-hydroxy-1-methylpropyl]-4-methoxy-5-methylpyran-2-one (1), 6-[(1E)-3-hydroxy-1-methylpropenyl]- 4-methoxy-3-methylpyran-2-one (2), 4,6-dihydroxy-5-methoxy-2-(7-methyl-3-methyleneoct-6-en-1-ynyl)cyclohex-2-enone (3), and 2,5-dihydroxy-6-methoxy-3-(7-methyl-3-methyleneoct-6-en-1-ynyl)cyclohex-3-enone (4) using spectroscopic and chemical methods. The absolute configuration of the hydroxylated secondary carbon of the 2-hydroxy-1-methylpropyl side chain at C-6 of gulypyrone A was determined as S by applying a modified Mosher’s method. Other well-known metabolites were also isolated including 3-nitropropionic, succinic, and p-hydroxy- and p-methylbenzoic acids, p-hydroxybenzaldehyde, and nectriapyrone. When assayed using a 5 mM concentration on punctured leaf disks of weedy and crop plants, apart from 3-nitropropionic acid (the main metabolite responsible for the strong phytotoxicity of the culture filtrate), phomentrioloxin B caused small, but clear, necrotic spots on a number of plant species, whereas gulypyrone A caused leaf necrosis on Helianthus annuus plantlets. All other compounds were weakly active or inactive

Orthostatic Tremor is Responsive to Bilateral Thalamic Deep Brain Stimulation: Report of Two Cases Performed Asleep

Background: Orthostatic tremor (OT) is a hyperkinetic movement disorder characterized by rapid tremor in the lower extremities or trunk upon standing. Case Report: We report two patients presenting with OT, whose symptoms improved markedly following asleep bilateral thalamic deep brain stimulation (DBS) surgery. Discussion: Medically refractory OT can respond favorably to asleep bilateral DBS surgery similar to awake surgery, and may have the advantages of less psychological trauma to the patient, shorter procedure times, and less exposure to anesthesia

Phytotoxic metabolites produced by Botryosphaeriaceae involved in grapevine trunk diseases

Fungi belonging to the Botryosphaeriaceae family are well known as cosmopolitan pathogens, saprophytes and endophytes and occur on a wide range of hosts including grapevine. More recently, a new species of Lasiodiplodia was isolated from declining grapevines in Sardinia (Italy). This still undescribed species showed to produce in liquid culture several phytotoxic secondary metabolites. In this communication the chemical and biological characterization of these bioactive secondary metabolites is discussed together with their role in the pathogenesis process

Spasmodic dysphonia may respond to bilateral thalamic deep brain stimulation

Background Spasmodic dysphonia is a primary focal dystonia manifested by loss of control of the vocal muscles during speech secondary to laryngeal muscle spasms. The pathophysiology is not well understood. Deep brain stimulation surgery (DBS) for other focal dystonias has been well reported. Methods We report the first case of bilateral thalamic DBS improving spasmodic dystonia (SD) in a patient with essential tremor.Results This case demonstrates the beneficial of effects of bilateral thalamic DBS for both ET of the hands and AdSD of the vocal cords.Conclusions The potential pathophysiologic mechanisms of this finding are discussed

Phytotoxins produced by pathogenic fungi for the integrated management of noxious weeds

Weeds infest economically important crops causing marked losses in agrarian production, forests, and ornamental heritages. Weed pests, including parasitic plants, have always being recognised as one of the most serious agricultural and environmental problems due to competition with the growth of agrarian crops and forest plants by subtraction of water, nutrients, light and by the serious obstacles they represent for agronomic activities. A number of weed management strategies have been followed in agriculture production, including mechanical, cultural, chemical, and biological strategies. The use of soil physical mechanical and cultural methods do not provide a satisfactory solution to weed problems. On the other hand, the use of chemical pesticides differing widely in respect to spectrum, unit activity, crop safety, toxicology, and environmental effects has increased herbicidal resistance and environmental and toxicological concerns raise a question mark over their large scale use. Consequently, many efforts were focused on the development of alternative strategies based on the use of natural products and in particular on the use of fungal phytotoxins alone as natural herbicides and/or in combination with fungal producers in a more efficient and integrated management. Fungal phytotoxins are secondary metabolites that belong to different classes of naturally occurring compounds. They play an important role in the induction of disease symptoms in agrarian and forest plants and weeds. This thesis reports on the isolation, purification and chemical and biological characterization of phytotoxins produced by four fungi proposed as potential mycoherbicides for the biological control of some noxious weeds: a) Diaporte gulyae and D. kongii, fungi proposed as potential mycoherbicides of Carthamus lanatus L. ssp. lanatus, a widespread winter-growing annual weed of both pastures and crop throughout Australia introduced from the Mediterranean region. b) Alternaria sonchi, fungus evaluated as a possible biocontrol agent of Sonchus arvensis L., commonly called perennial sowthistle, a plant species considered to be an important weed in Europe and North America as it infests many habitats such as cultivated fields, roadsides, pastures and rangelands, railway embankments, and lawns. c) Phoma chenopodiicola, fungus proposed as potential mycoherbicide for the control of Chenopodium album (common lambsquarters or fat-hen), one of the most successful colonizing species, which has been reported to infest plantations of sugar beets, potatoes, maize, cereals, and vegetables all over the world

Circularly polarized luminescence of natural products lycorine and narciclasine: role of excited-state intramolecular proton-transfer and test of pH sensitivity

: Circularly polarized luminescence (CPL) is increasingly gaining interest not only for its applicative potentialities but also for providing an understanding of the excited state properties of chiral molecules. However, applications of CPL are mainly in the field of materials science: special organic molecules and polymers, metal (lanthanide) complexes, and organic dyes are actively and intensely studied. So far natural compounds have not been investigated much. We fill the gap here by measuring circular dichroism (CD) and CPL of lycorine and narciclasine, the most abundant known alkaloid and isocarbostyril from Amaryllidaceae, which exhibit a large spectrum of biological activities and are promising anticancer compounds. Dual fluorescence detection in narciclasine led us to unveil an occurring excited-state intramolecular proton transfer (ESIPT) process, this mechanism well accounts for the Stokes shift and CPL spectra observed in narciclasine. The same molecule is interesting also as a pH chiroptical switch. Both in absorption and emission, lycorine and narciclasine are also studied computationally via density functional theory (DFT) calculations further shedding light on their properties

The Surprising Story of Fusicoccin: A Wilt-Inducing Phytotoxin, a Tool in Plant Physiology and a 14-3-3-Targeted Drug

Fusicoccin is the alpha glucoside of a carbotricyclic diterpene, produced by the fungus Phomopsis amygdali (previously classified as Fusicoccum amygdali), the causal agent of almond and peach canker disease. A great interest in this molecule started when it was discovered that it brought about an irreversible stomata opening of higher plants, thereby inducing the wilting of their leaves. Since then, several studies were carried out to elucidate its biological activity, biosynthesis, structure, structure-activity relationships and mode of action. After sixty years of research and more than 1800 published articles, FC is still the most studied phytotoxin and one of the few whose mechanism of action has been elucidated in detail. The ability of FC to stimulate several fundamental plant processes depends on its ability to activate the plasma membrane H+-ATPase, induced by eliciting the association of 14-3-3 proteins, a class of regulatory molecules widespread in eukaryotes. This discovery renewed interest in FC and prompted more recent studies aimed to ascertain the ability of the toxin to influence the interaction between 14-3-3 proteins and their numerous client proteins in animals, involved in the regulation of basic cellular processes and in the etiology of different diseases, including cancer. This review covers the different aspects of FC research partially treated in different previous reviews, starting from its discovery in 1964, with the aim to outline the extraordinary pathway which led this very uncommon diterpenoid to evolve from a phytotoxin into a tool in plant physiology and eventually into a 14-3-3-targeted drug

Antifungal metabolites produced by <i>Trichoderma viride</i> against <i>Sclerotium rolfsii</i>

In this comunication we report our progress regarding the isolation and characterization of new antifungal metabolites from this strain of T. viride