Aesculus pavia foliar saponins: defensive role against the leafminer Cameraria ohridella

BACKGROUND: Recently, the leafminer Cameraria ohridella Deschka & Dimic has caused heavy damage to the white‐flowering horse chestnut in Europe. Among the Aesculus genus, A. pavia L. HBT genotype, characterised by red flowers, showed an atypical resistance towards this pest. Its leaves, shaken in water, originated a dense foam, indicating the presence of saponins, unlike the common horse chestnut tree. The aim was to isolate and identify these leaf saponins and test their possible defensive role against C. ohridella. RESULTS: Spectroscopic analyses showed that A. pavia HBT genotype leaves contained a mixture of saponins, four of which were based on the same structure as commercial escin saponins, the typical saponin mixture produced by A. hippocastanum and accumulated only within bark and fruit tissues. The mixture showed a repellent effect on C. ohridella moth. The number of mines detected on the leaves of A. hippocastanum plants treated with A. pavia HBT saponins through watering and stem brushing was significantly lower than the control, and in many cases no mines were ever observed. CONCLUSION: The results showed that the exogenous saponins were translocated from roots/stem to the leaf tissues, and their accumulation seemed to ensure an appreciable degree of protection against the leafminer. Copyright © 2010 Society of Chemical Industry     

Fusarium species and chemotypes associated with fusarium head blight and fusarium root rot on wheat in Sardinia

Environmental conditions in Sardinia (Tyrrhenian Islands) are conducive to fusarium root rot (FRR) and fusarium head blight (FHB). A monitoring survey on wheat was carried out from 2001 to 2013, investigating relations among these diseases and their causal agents. FHB was more frequently encountered in the most recent years while FRR was constantly present throughout the monitored period. By assessing the population composition of the causal agents as well as their genetic chemotypes and EF‐1α polymorphisms, the study examined whether the two diseases could be differentially associated to a species or a population. Fusarium culmorum chemotypes caused both diseases and were detected at different abundances (88% 3‐ADON, 12% NIV). Fusarium graminearum (15‐ADON genetic chemotype) appeared only recently (2013) and in few areas as the causal agent of FHB. In F. culmorum, two haplotypes were identified based on an SNP mutation located 34 bp after the first exon of the EF‐1α partial sequence (60% adenine, 40% thymine); the two populations did not segregate with the chemotype but the A‐haplotype was significantly associated with FRR in the Sardinian data set (P = 0·001), suggesting a possible fitness advantage of the A‐haplotype in the establishment of FRR that was neither dependent on the sampling location nor the sampling year. The SNP determining the Sardinian haplotype is distributed worldwide. The question whether the A‐haplotype segregates with characters facilitating FRR establishment will require further validation on a specifically sampled international data set.     

New cholinesterase inhibiting bisbenzylisoquinoline alkaloids from Abuta grandifolia

The phytochemical study of the stem bark and wood of Abuta grandifolia (Mart.) Sandwith led to the identification of four bisbenzylisoquinoline alkaloids (BBIQs), namely (R,S)-2 N-norberbamunine (1), (R,R)-isochondodendrine (2), (S-S)-O4″-methyl, Nb-nor-O6'-demethyl-(+)-curine (3), and (S-S)-O4″-methyl, O6'-demethyl-(+)-curine (4), together with the aporphine alkaloid R-nornuciferine (5), all obtained by countercurrent distribution separation (CCD) and identified on the basis of their spectroscopic data. Alkaloids 3 and 4 were new. All the isolated compounds were tested for acetylcholinesterase (AChE) and butyrylcholinesterase (BChE) inhibitory activities. 1 was the most active against AChE, whereas 3 and 4 were the most potent against BChE. Interestingly, all tested alkaloids are more potent against BChE than against AChE. This selectivity of cholinesterase (ChE) inhibition could be important in order to speculate on their potential therapeutic relevance.     

The effect of soil texture on the water use efficiency of irrigated crops: Results of a multi-year experiment carried out in the Mediterranean region

The effect of soil texture on water use efficiency (WUE) was analyzed for six crops cultivated on loam and clay soils. Results were obtained after a long-term study, carried out in a lysimetric set-up, in conditions of experimental neutrality (climate, agro-techniques, and variety were the same for each crop) with the sole exception of the soil texture, which was the variable to be studied.In the case of potato, corn, sunflower, and sugar beet, WUE was reduced significantly when crops were grown in clay soil. The reductions ranged from 22% to 25%. The decrease of WUE in clay soil was coupled with significant reductions in yield and in ET, except in the case of the corn crop. The reduction in WUE in corn depended solely on the yield decrease.A 10% decrease in WUE values was also observed for the soy-bean and tomato grown in clay soil, but it was not statistically significant.Different causes which may reduce the WUE values observed in the clay soil are discussed. It seems coherent to hypothesize that, during the active growing phase, a deficit in water uptake occurs in the plants growing in the clay soil. This hypothesis is consistent with the observations of stomatal conductance, daily evapotranspiration, and leaf surface.In conclusion, the operative development of this study is outlined.     

Detection of comorbidities and synchronous primary tumours via thoracic radiography and abdominal ultrasonography and their influence on treatment outcome in dogs with soft tissue sarcomas,primary brain tumours and intranasal tumours

Canine soft tissue sarcomas (STS), primary brain tumours and intranasal tumours are commonly treated with radiotherapy (RT). Given the low metastatic potential of these tumours, recommendations regarding imaging tests as staging are variable among institutions. The purpose of our study was to describe thoracic radiographic and abdominal ultrasonographic findings in dogs with these neoplasms and to investigate association of abnormal findings with alterations in recommended treatment. Medical records from 101 dogs, each having thoracic radiographs and abdominal ultrasound performed as part of their staging, were reviewed. In 98 of 101 (97%), imaging abnormalities were detected, 27% of which were further investigated with fine needle aspiration cytology or biopsy. Nine percent of the detected abnormalities were considered serious comorbidities that altered treatment recommendations, including 3 (3%) which were confirmed as synchronous primary neoplasms. These findings may influence recommendations regarding the decision to perform thoracic radiographs and abdominal ultrasound prior to initiation of RT.     

Conservation problems with hypothelminorheic Niphargus species (Amphipoda: Niphargidae)

• 1. The hypothelminorheic is a unique superficial subterranean habitat, harbouring troglomorphic species that are unique to this habitat or share species with other subterranean habitats. These species are especially vulnerable to disturbance and human impact.
• 2. The ecological needs of the sympatric Niphargus slovenicus and Niphargus sphagnicolus from central Slovenia were examined in order to assess whether similar conservation strategies could be applied for the two species.
• 3. Their habitat patches appeared to be variable with respect to abiotic factors, and the ecological requirements of the two species differ. A major discriminatory factor is pH.
• 4. The results imply that the conservation strategies for sympatric hypothelminorheic species cannot be generalized; additional research for the case study is discussed. Copyright © 2010 John Wiley & Sons, Ltd.

     

Modeling of urea degradation in white and rosé wines by acid urease

The specific activity of a whole cell acid urease preparation was tested in five wines manufactured in the Apulia region of Italy in the 2003 vintage at both short and long treatment times, thus confirming the validity of the pseudo-first-order kinetic model to describe urea removal in real wines. The ratio between the experimental pseudo-first-order kinetic rate constant (kIe) for any real wine tested and that (kI) referred to a model wine solution having the same composition and pH reduced from about 0.21 to 0.02 as the overall content of phenolic compounds (P) increased from 109 to 853 g m-3 of gallic acid equivalent (GAE). The specific inhibitory effect of such compounds was explained by accounting for the equilibrium constant (KP) of the reaction of polyphenols with acid urease, which was found to be about 21 g of GAE m-3 for the real wines tested, whereas it ranged from about 16 to 45 g of GAE m-3 when the model wine solution was enriched with tannins extracted from grape seeds or skins, respectively. A sequential experimental procedure consisting of accelerated acid urease tests at high doses of enzyme followed by accelerated ethyl carbamate tests on the resulting acid urease treated wine was recommended to assess preliminarily the technoeconomic feasibility of the acid urease hydrolytic process for the wine of concern. Keywords: Acid urease; real and model wines; phenolics; pseudo-first-order kinetic rate constant; inhibitory effect; urea degradation kinetics.     

Assessment of urea degradation rate in model wine solutions by acid urease from Lactobacillus fermentum

The specific activity (piA) of a whole cell acid urease preparation was assessed in model wine solutions at different levels of malic (M) and lactic acids, metabisulfite, ethanol, and pH by performing a central composite design. M and then pH were found to be the most controlling variables, their effects being practically coincident but of opposite sign. For urea concentrations up to approximately 1 mol m(-3) the ammonium formation rate was assumed of the pseudo-first-order with respect to urea, this being confirmed by two independent validation tests performed at 20 degrees C for as long as 24 h. In the case of real wines the effective pseudo-first-order kinetic rate constants were found to be smaller than those pertaining to the model solutions having the same wine composition and pH by a factor varying from 10 to 1000, this affecting significantly the specific urease treatment costs per liter of wine treated.