Characterization of DMI,QoI and SDHI fungicides sensitivity of Ramularia collo-cygni isolates in Argentina

Journal of Plant Diseases and Protection - Ramularia leaf spot (RLS) caused by the fungus Ramularia collo-cygni (Rcc) has become a threat to barley production in Argentina. All barley varieties are...     

Characterization of catecholase and cresolase activities of eggplant polyphenol oxidase

In the present paper the catecholase and cresolase activities of eggplant polyphenol oxidase (PPO) are described. To preserve the latter activity, a partially purified enzyme was used. Peroxidase was removed from the preparation to avoid its interference with PPO during phenol oxidation. The partially purified eggplant PPO was fully active. The catecholase/cresolase ratio of 41.1 indicated that, in a pH close to the physiological, diphenol oxidation predominates over monophenol oxidation. The characteristic lag phase of the cresolase activity is modulated by the pH, the monophenol and diphenol concentrations, and the enzyme's concentration. The effect of several inhibitors was also tested, and the K(i) values of the two most effective (tropolone and 4-hexylresorcinol) were determined.     

Evaluation and correction of nutrient availability to Gerbera jamesonii H. Bolus in various compost-based growing media

Nutrient deficiencies usually constrain the use of some composted materials as peat-substitute growing media even if some fertilizer is applied to the media. In this work, we assessed the suitability of various composted materials as such or mixed with peat for potted plant production, with special emphasis on their effects on nutrient availability to plants. Further, we examined the effect of vivianite [Fe₃(PO₄)₂·8H₂O] as a fertilizer and its mixture with humic substances (HS) on these growing media (particularly their effectiveness in preventing Fe deficiency chlorosis in alkaline substrates). A completely randomized experiment design was developed involving the growth of gerber (Gerbera jamesonii H. Bolus) and two factors, namely (i) the growing medium, specifically composted cork residue (C), compost obtained from a mixture of olive husk and cotton gin trash mixed with rice hulls and peat in a 1:1:1 volume proportion (OH), composted grape marc (GM), Sphagnum peat mixed with spent mushroom compost (M), coconut fibre (CF), and Sphagnum peat; and (ii) the Fe source (control without Fe, Fe-EDDHA, vivianite and vivianite + HS in a weight ratio of 10:1).     

Generation of saffron volatiles by thermal carotenoid degradation

Generation of volatiles by thermal treatments has been studied in saffron spice for two reasons: (a) to determine volatile profile changes during simulated aging processes and (b) to study the volatile generation pathway. During the aging process, while the amounts of C10 compounds such as safranal and HTCC increase, the amounts of C9 compounds such as isophorone and 2,6,6-trimethylcyclohexane-1,4-dione decrease. A new compound tentatively identified as 4,5,6,7-tetrahydro-7,7-dimethyl-5-oxo-3H-isobenzofuranone seems to play a very important role in the aging process. The importance of this compound, structurally similar to dihydroactindiolide, was also confirmed when the saffron volatile fraction was analyzed via the degradation of the linear chain of crocetin and crocetin esters and is reported for the first time in this paper. Thermal degradation studies of zeaxanthin, crocetin, and trans and cis crocetin esters isomers allowed us to propose different mechanisms which explain saffron volatile generation depending on the crocetin ester isomer structure.     

Effect of centrifugal ultrafiltration on the composition of aqueous extracts of saffron spice (Crocus sativus L.)

The purpose of this research was to study the effect of centrifugal ultrafiltration (UF) on the composition of aqueous extracts of saffron spice. The contents of seven crocetin esters, picrocrocin, and two kaempferol glycosides were analyzed by UV-vis and HPLC in the filtrate and retentate fractions from 16 centrifugal filter devices with regenerated cellulose (RC) and polyethersulfone (PES) membranes ranging from 1-100 kDa nominal molecular weight cutoff (MWCO). The separation of crocetin esters from picrocrocin and their concentration with centrifugal UF have been demonstrated. A great heterogeneity of results regarding devices with equal MWCO was found that could not be related to the membrane material or manufacturer. Four devices of 5 and 10 kDa MWCO, three of which had RC membranes, showed the best results. The device having the lowest MWCO also showed a potential to obtain picrocrocin without crocetin esters and could be considered in successive UF steps. The less polar crocetin esters were rejected better than the others.     

Association between circulating angiotensin-converting enzyme and exercise-induced pulmonary haemorrhage in Thoroughbred racehorses

Exercise-induced pulmonary haemorrhage has an impact on racehorse performance. Although endoscopic diagnosis (with or without the aid of bronchoalveolar lavage) is considered to be the standard diagnostic method for this condition, the use of biomarkers that could aid in quantifying risk and severity of the condition would represent an advance in equine sport medicine. This preliminary research investigated the use of angiotensin-converting enzyme (ACE) activity in plasma of racehorses and demonstrated that ACE activity is increased in horses with higher degrees of haemorrhage and is a promising biomarker for EIPH in racehorses.     

Fat accumulation,fatty acids and melting point changes in broiler chick abdominal fat as affected by time of dietary fat feeding and slaughter age

1. This work aims to quantify changes in fatty acid profile, melting point, abdominal fat accumulation and 2-thiobarbituric acid-reactive substances production depending on dietary fat source and age at slaughter, and to estimate the optimal date for the change from an unsaturated fat to a saturated fat diet or vice versa.

2. Treatments established were (1) birds fed 8% tallow from 21 to 49 d (TTT); (2) birds fed 8% tallow from 21 to 37 d and 8% sunflower oil from d 38 to 49 (TSS); (3) birds fed 8% sunflower oil from 21 to 37 d and 8% tallow from d 38 to 49 (STT); (4) birds fed 8% sunflower oil from 21 to 41 d and 8% tallow from d 42 to 49 (SST); (5) birds fed 8% sunflower oil from 21 to 49 d (SSS). Birds from each group were slaughtered on d 21, 29, 38, 40, 42, 44, 46 and 49.

3. The polyunsaturated fatty acids (PUFAs) proportion in the SSS group reached maximum values at d 40 and fitted a quadratic response. This group also showed a decrease in saturated fatty acids (SATs) and monounsaturated fatty acids (MUFAs) of lower intensity than the PUFA increase. The highest synthesis of SAT + MUFA was found in the SSS and TSS groups, whereas these had the lowest body-to-dietary PUFA ratio.

4. A high and quadratic increase in the MUFA proportion was observed during the first 10 d of feeding with the tallow-enriched diet at the expenses of the proportion of PUFA that quadratically decreased (minimum values at d 38).

5. Lipogenic and desaturation capacity decreased with age.

6. The TSS group increased tissue PUFA content faster that the SST group decreased PUFA content after the change in diet which indicates that the earlier feeding has to be taken into consideration for obtaining higher or lower changes in quality parameters.

7. The melting point of the SSS group showed a lower response to the dietary treatment in the initial period when compared to the TTT treatment.

8. The TTT, STT, SST and TSS groups showed similar fat accumulation, and changes in lipid oxidation were related to the day of dietary sunflower oil supplementation.

9. Based on the results, it would be possible to determine the most appropriate dietary programme and optimum slaughter age to obtain chicken meat with the desired quality characteristics.     

Olive Husk Compost Improves the Quality of Intensively Cultivated Agricultural Soils

Organic amendments improve the quality of degraded cultivated agricultural soils. In this work, we examined the impact of an olive husk compost (OHC) on quality‐related physical, chemical and biochemical properties of intensively managed greenhouse soil. To this end, a completely randomized block experiment involving a single factor and two treatments (viz., annual application of OHC at 30 Mg ha⁻¹ or no application) with three replications was used for 5 years. The effect of the compost was studied at two soil depths (0–10 and 10–25 cm) and two positions relative to crop rows (viz., on rows and between rows). Application of OHC increased soil organic matter (SOM) content, which is consistent with the low degradation rate of the compost in soil and confirms its usefulness as a source of organic C for soil. Increased SOM content resulted in decreased bulk density, and also in increased porosity and available water in the soil. The amendment was also an effective source of nutrients, particularly N, P, K and Ca, the last of which contributed to decrease exchangeable Na levels in the soil surface layer. The compost increased the activity of all enzymes studied except urease. This result can be ascribed to increased microbial activity, the presence of enzymes in the compost and their stabilization by organic matter and clay in the soil. Dehydrogenase and phosphatase were the individual enzyme activities in the soil, which were correlated with the largest number of soil properties favourably affected by OHC. Copyright © 2015 John Wiley & Sons, Ltd.