39,420 research outputs found
Sphaeropsidins B and C, phytotoxic pimarane diterpenes from Sphaeropsis sapinea f. sp. Cupressi and Diplodia mutila
No full textTwo phytotoxic pimarane diterpenes, named sphaeropsidins B and C, were isolated from two phytopathogenic fungi causing canker diseases of Italian cypress (Cupressus sempervirens L.): Sphaeropsis sapinea f, sp. cupressi and Diplodia mutila. S. sapinea f sp. cupressi produced both phytotoxins, whereas D. mutila produced sphaeropsidins C and A, the latter also being reported as the main phytotoxin of S. sapinea f. s. cupressi. Characterized by chemical and spectroscopic methods, sphaeropsidin B proved to be a known fungal metabolite for the first time isolated from S. sapinea f. sp. cupressi, while sphaeropsidin C is a new tricyclic acid pimarane diterpene produced by both fungi. Assayed on severed twigs of cypress and oak, sphaeropsidins B and C caused dieback on C. macrocarpa, browning and necrosis on C. sempervirens and yellowing on C. arizonica, necrosis on Quercus cerri and e. ilex, and browning and necrosis on Q, robur. When injected into cortical tissues of cypress and oak seedlings mentioned above, they caused on the former dark brown discolouration, browning of internal tissues and browning, and brown-blackish spots or necrotic lesions on the latter. On non-host plants like tomato and oat, sphaeropsidins B an C caused necrosis on cuttings and brown discolouration or stewing on the stem. In the antimicrobial assay, both compounds showed an inhibitory effect on mycelial growth of seven test fungi. (C) 1997 Elsevier Science Ltd
Sphaeropsidin F, a new pimarane diterpene produced in vitro by the cypress pathogen Sphaeropsis sapinea f. sp. cupressi
No full textA new pimarane diterpene was isolated from liquid cultures of Sphaeropsis sapinea f. sp. cupressi, a plant pathogenic fungus causing a form of canker disease of Italian cypress (Cupressus sempervirens L.). The metabolite, characterized by spectroscopic methods, was named sphaeropsidin F. When assayed on test plants sphaeropsidin F caused less severe symptoms that those of sphaeropsidin A, which is the main toxin produced by this fungus. A solution of sphaeropsidin F (0.1 mg mL–1) tested on severed cypress twigs caused yellowing of the apical leaves of C. sempervirens twigs, whereas C. macrocarpa and C. arizonica were not affected. This shows that the three cypress species had a different grade of sensitivity to the action of the toxin. As already demonstrated for rings B and C, the modification of the A ring strongly reduced the biological activity of the molecule
Environmental settings of agricultural practices in central Italy during the first half of the first millennium BCE
No full textOne of the main transformations in the western Mediterranean is the birth and surge of urban life during the first half of the 1st millennium BCE. This urbanization process is usually linked with an intensification of food production and changes in agricultural practices. However, it is not well known how the relationships between their different parameters were reshaped during this period.
This phenomenon was observed in Central Tyrrhenian Italy from the Bronze Age to the Archaic period (12th to 6th c. BCE). Over the span of a few centuries the sparse clusters of huts observed during the Bronze Age evolved into city-state urban centers such as Rome or Tarquinia. Some of the aspects of these changes are still under debate including what kind of agricultural practices sustained the development of these early urban centers. Importantly, there is much that we do not know about possible environmental factors that could have triggered or influenced these processes in multiple and complex ways. Climatic instability has been reconstructed for this period but its role in the social cultural development of the region has not yet been assessed. The present research question lies in the interplay between environment, climate, agriculture and urbanization processes that occurred in Central Tyrrhenian Italy during the first half of the 1st millennium BCE.
Three archaeological sites that underwent this process of urbanization (Palatine Hill located in Rome, Gabii and Tarquinia) were selected for this study. They all provided charred archaeobotanical material (seeds, fruits and wood) dated from the 10th to the 5th c. BCE. Two complementary methods were used to answer the research question: The first was the study of the archaeobotanical material which informs on crop production; The second was the use of carbon and nitrogen stable isotope analysis. This innovative method helps to gather information about the field environment and management. Specifically, it allows us to study the water availability in which plants grew with the measure of the Δ13C as well as to identify possible application of manure through the δ15N results.
The archaeobotanical study resulted in a total of about 30400 seeds, fruits and fragments from the three archaeological sites. The analysis showed a dominance of cereals, with barley and emmer being the main staples. Pulses were the second most important category represented mainly by fava beans and bitter vetch. Some differences in the proportions of crops were identified among sites suggesting cultural or economic preferences since the three sites lie in the same environmental region. Weeds of arable fields, which are good environmental indicators, were also identified in large quantities but due to their ubiquity, they were not discriminant.
Carbon and nitrogen stable isotope analyses (δ13C and δ15N) were performed on 557 charred barley and emmer caryopses from the three archaeological sites. The results show some variation in water availability across time for both species. The δ15N values are, overall, low and no difference across time or periods was identified. This suggests that no manuring practices were commonly used during this period.
A pilot study on 270 fragments of wood charcoal from Gabii to reconstruct the environment of the spontaneous flora in the region. Taxonomic identification shows a prevalence of deciduous oak forests and the surprising presence of beech which, according to the regional paleoenvironment studies, should not be present anymore in low altitudes. Ten charcoal fragments of deciduous oak were selected for isotope analysis. They were radiocarbon dated (14C) and δ13C was calculated to explore past natural environmental water availability. The comparison with the trends identified in the crops is used to discriminate environmental from anthropic factors. The14C results obtained show a large range in terms of dating which was expected as the period of interest falls into the Hallstatt plateau, a flat area between the 9th and the 5th c. BCE on the reference curve used for calibration (Trias et al. 2020). This makes it challenging to put the charcoal fragments in sequence and consequently compare their trend with the cereal ones. Different methods to overcome this are currently being explored and the addition of more charcoal fragments should help.
It is the first time that this kind of work is undertaken in this region and for this period. It represents an innovative work which contributes greatly to the understanding of the complex mechanisms and evolution occurring during this period
RECTIFIER FOR A GENERATOR OF REFRIGERANT VAPOUR FOR ABSORPTION THERMAL MACHINES, AND GENERATOR COMPRISING SUCH RECTIFIER
No full textRectifier (100) for a generator (200) of refrigerant vapour, said rectifier being adapted to modify the percentage of a refrigerant substance present in vapour flows (V) generated by boiling a liquid solution (L) comprising at least one absorbent substance and a refrigerant substance absorbed and characterized in that it comprises at least: • - a casing (101) which extends along a substantially vertical reference axis (X) and includes at least a first transversal duct (102) suitable for allowing the introduction of flows of said liquid solution (L) to be boiled; • - at least a first body (105) consisting of an open cell ceramic foam which is housed in said casing (101) below said first duct (102) so as to be crossed by flows of the liquid solution (L) to be boiled which, going downwards, wet its surfaces, and by vapour flows (V) generated by boiling which, going upwards, exchange heat with the solution itself which wets the surfaces of the first body (105), causing at the same time evaporation of refrigerant from the liquid solution (L) and the condensation of at least a part of the absorbent substance contained in said vapour streams (V) going upwards
Erratum to: Effect of moderate red wine intake on cardiac prognosis after recent acute myocardial infarction of subjects with Type 2 diabetes mellitus (Diabetic Medicine, (2006), 23, 9, (974-981), 10.1111/j.1464-5491.2006.01886.x)
No full textIn an article by Marfella et al, the author name C. Saron is incorrect and should be listed as C. Sardu. Therefore the correct author list is: R. Marfella, F. Cacciapuoti, M. Siniscalchi, F. C. Sasso, F. Marchese, F. Cinone, E. Musacchio, M. A. Marfella, L. Ruggiero, G. Chiorazzo, D. Liberti, G. Chiorazzo, G. F. Nicoletti, C. Sardu, F. D'Andrea, C. Ammendola, M. Verza and L. Coppola.In an article by Marfella et al, the author name C. Saron is incorrect and should be listed as C. Sardu. Therefore the correct author list is: R. Marfella, F. Cacciapuoti, M. Siniscalchi, F. C. Sasso, F. Marchese, F. Cinone, E. Musacchio, M. A. Marfella, L. Ruggiero, G. Chiorazzo, D. Liberti, G. Chiorazzo, G. F. Nicoletti, C. Sardu, F. D'Andrea, C. Ammendola, M. Verza and L. Coppola
Sphaeropsidone and episphaeropsidone, phytotoxic dimedone methyl ethers produced by Sphaeropsis sapinea f. sp. cupressi grown in liquid culture
No full textTwo phytotoxic dimedone methyl ethers, named sphaeropsidone and episphaeropsidone, were isolated from Sphaeropsis sapinea f sp. cupressi, a phytopathogenic fungus causing a canker disease of Italian cypress (Cupressus sempervirens L.). The same fungus produced the sphaeropsidins A, B and C, which are three phytotoxins recently chemically characterized as pimarane diterpenes. Sphaeropsidone and episphaeropsidone were characterized, using essentially spectroscopic methods, as two new phytotoxic disubstituted 7-oxabicyclo[4.1.0]hept-3-en-2-ones, which are epimers at C-5. Assayed on severed twigs of cypress, sphaeropsidone caused browning and necrosis on Cupressus macrocarpa, no symptoms on C. sempervirens and chlorosis on C. arizonica. Episphaeropsidone caused necrosis on C. macrocarpa, browning and necrosis on C. sempervirens and necrosis on C. arizonica. On the non-host plant tomato, both phytotoxins caused wilting. In a microbial assay, both compounds showed an inhibitory effect on the growth of five fungal species tested. The growth of Vertcillium dahliae was enhanced by both dimedone methyl ethers. (C) 1998 Elsevier Science Ltd. All rights reserved
A phytotoxic pimarane diterpene of Sphaeropsis sapinea f. sp. cupressi, the pathogen of a canker disease of cypress
No full textA phytotoxic metabolite, named sphaeropsidin A, is produced in vitro by Sphaeropsis sapinea f. sp. cupressi, a fungus that causes a canker disease of Italian cypress (Cupressus sempervirens). The spectroscopic data indicates that sphaeropsidin A is identical with a pimarane diterpenoid antibiotic previously isolated from some Aspergillus spp. When absorbed by severed twigs of three species of Cupressus and cuttings of two herbaceous plants, sphaeropsidin A at 0.1 mg ml-1 produced leaf yellowing, browning and dieback and yellowing of leaf, necrosis and epinasty, respectively. Subperidermal injection of a 0.1 mg ml-1 solution of sphaeropsidin A into young cypress trees caused longitudinal fissures and dark brown discolouration of cortical tissues. The compound showed antimicrobial activity towards 12 fungal species when assayed at a concentration range from 10 to 100 mu-g ml-1. This is the first report showing that sphaeropsidin A is a non-selective fungal phytotoxin
Sous-facteurs de L(F∞) d'indice 4cos2π/n,n≥3
No full textLet Q be a factor of type II1, λ a number in the Jones discrete series {4cosπ/m:m≥3}, and {ei} the Jones projections associated with λ. Denote by A2n and A1n the finite-dimensional von Neumann algebras generated, respectively, by {1,e2,⋯,en} and {1,e1,⋯,en}, with the corresponding traces. The author shows that, for n sufficiently large, the index of the inclusion An=(Q⊗A2n)∗A2nA1n⊂(Q⊗A2n+1)∗A2n+1A1n+1=An+1 is equal to λ (here ∗ denotes the reduced, amalgamated free product of the algebras in question). Using the random matrix model of Voiculescu, he proves that if Q is the von Neumann algebra L(F∞) of the free group with infinitely many generators, then An is isomorphic to L(F∞).
The two facts together imply the existence, for any λ in the Jones discrete series, of an irreducible subfactor of L(F∞) of index λ. This constitutes the first example of a nonhyperfinite, non-Γ II1 factor such that its Jones invariant is fully computable (the existence of nonirreducible subfactors of L(F∞) for any index ≥4 is a simple consequence of known results)
Il trattamento dei tumori glottici in microlaringoscopia diretta in sospensione mediante l’impiego del Laser a CO2.
No full textSphaeropsidin F, a new pimarane diterpene produced in vitro by the cypress pathogen Sphaeropsis sapinea f. sp. cupressi
No full textA new pimarane diterpene was isolated from liquid cultures of Sphaeropsis sapinea f. sp. cupressi, a plant pathogenic fungus causing a form of canker disease of Italian cypress (Cupressus sempervirens L.). The metabolite, characterized by spectroscopic methods, was named sphaeropsidin F. When assayed on test plants sphaeropsidin F caused less severe symptoms that those of sphaeropsidin A, which is the main toxin produced by this fungus. A solution of sphaeropsidin F (0.1 mg mL–1) tested on severed cypress twigs caused yellowing of the apical leaves of C. sempervirens twigs, whereas C. macrocarpa and C. arizonica were not affected. This shows that the three cypress species had a different grade of sensitivity to the action of the toxin. As already demonstrated for rings B and C, the modification of the A ring strongly reduced the biological activity of the molecule
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