Spread of potato virus Y in potato cultivars (Solanum tuberosum L.) with different levels of sensitivity

The aim of this work was to correlate the appearance of the symptoms, multiplication and spread of virus after mechanical inoculation of potato (Solanum tuberosum L.) cultivars showing different levels of susceptibility and sensitivity to Potato virus Y^NTN (PVY^NTN). The potato cultivars used were the resistant cultivar Sante and susceptible cultivars Igor, Pentland squire and Désirée. The spread of the virus PVY^NTN in infected plants was monitored using different methods: DAS-ELISA, tissue printing, immuno-serological electron microscopy and real-time PCR. In all three susceptible cultivars, the virus was detected in the inoculated leaves 4–5 days after inoculation. From there virus spread rapidly, first into the stem, then more or less simultaneously to the upper leaves and roots. Real-time PCR was shown to be very sensitive and enabled viral RNA to be detected in non-inoculated leaves of susceptible cultivar Igor earlier than other methods. Therefore, for exact studies of plant–virus interaction, a combination of methods which detect viruses on the basis of their different properties (coat protein, morphology or RNA) should be used to monitor the spread of viruses.     

Relationship between serum cortisol levels and some physiological parameters following reining training session in horse

The changes of cortisol, red blood cells (RBC), hemoglobin (Hb), hematocrit (Hct), heart rate (HR), respiratory rate (RR) and rectal temperature (RT) were evaluated after a reining training session in eight Quarter Horses. All parameters were measured before exercise (T0), immediately after exercise (T1), 1 h after exercise (T2), 2 h after exercise (T3) and 24 h after exercise (T4). One‐way analysis of variance (ANOVA) for repeated measures, followed Bonferroni's post hoc test, showed a significant effect of the reining training session (P < 0.0001) on cortisol, RBC, Hb, Hct, HR, RR and RT. Simple linear regression analysis showed the positive correlation (P < 0.05) between cortisol changes and variations of studied parameters in T1, T3 and T4. Exercise‐induced cortisol concentrations reflect the physiological response of reining training, suggesting that the changes observed are useful to assess the performance in reining horses and their reining training adaptability.     

Comparative Study of the Adsorption Selectivity of Cr(VI) onto Cationic Hydrogels with Different Functional Groups

Two types of hydrogels with different functional groups, trimethylamine on quaternary ammonium and dimethylethoxyamine on quaternary ammonium, were synthesized. Type 1 and type 2 hydrogels were characterized with Fourier transform infrared, X-ray photoelectron spectroscopy and zeta potential analysis. The anion selectivity of these two hydrogels was investigated. The surface charges of the type 2 hydrogel were lower than those of type 1, probably because of the presence of the hydroxyl group in the ethoxy group. The Cr(VI) removal capacity of type 2 hydrogel was, therefore, less than that of type 1 hydrogel, although their adsorption rates were similar. The anion selectivity of the hydrogels was found to have a similar order: Cr(VI) > sulphate > bromide > As(V). Under the co-presence of Cr(VI) and sulphate conditions, type 2 hydrogel shows a higher selectivity towards Cr(VI). The higher hydrophobicity was caused by the presence of the ethoxy group on the quaternary ammonium in type 2 hydrogel and thus increased in selectivity towards monovalent ions (i.e. HCrO₄⁻). In addition, the hydrogels have a high reusability. Compared with type 1 hydrogel, type 2 hydrogel has an advantage for applications in Cr(VI) removal and recovery processes.     

Selectivity in a trawl codend during haul-back operation—An overlooked phenomenon

The selectivity of a 99 mm trawl codend was assessed using a codend cover fitted with a MultiSampler, which was acoustically triggered to take separate samples at three different phases of the haul. The first sample was collected during towing, the second during haul-up and the third at the surface. A total of 18 hauls were conducted with a commercial fishing vessel west of Scotland. It was demonstrated that escapes take place not only during the tow but also in the short period when the trawl is hauled back from the seabed and when the codend is at the surface. For haddock (Melanogrammus aeglefinus), whiting (Merlangius merlangus) and Norway lobster (Nephrops norvegicus), respectively, the mean percentages escaping at the surface were 16, 12 and 38% of the total escape while 17, 8 and 28% escaped during the haul-up phase. Compared to towing, the escape rate (no./min) increased for haddock by a factor 2.7 during haul-up and by a factor 1.7 at the surface, whereas the escape rates of whiting were similar for the three phases. The escape rate of Norway lobster increased by a factor of approximately 7 for both the haul-up and surface phases, compared to the towing phase. The selectivity parameters L50 (50% retention length) and SR (selection range = L75–L25) were estimated and compared for the three different phases and for the whole haul for haddock, whiting and Norway lobster. For all three species there was no significant (P > 0.05) difference in L50 between the three phases of the haul. There was also no significant difference for whiting and Norway lobster when comparing the SR of the three phases, whereas the SR was significantly lower for haddock when comparing the surface phase with towing and haul-up. The estimate of L50 when towing was about 6 cm lower for haddock and whiting and 9 mm for Norway lobster compared to the selection curve estimated conventionally for the whole haul. Finally, the effect of sea state, duration and codend catch on the selectivity parameters were estimated for the individual phases and for the whole haul. A significant effect of at least one variable was found in all phases.     

Analysis of soil-vegetation systems' sensitivity to changes of climate-dependent carbon turnover parameters

 The nonlinear model of the carbon cycle in soils (NAMSOM) was used to analyze the sensitivity of soil organic matter levels to variations in carbon turnover parameters. We were able to predict the sensitivity of soil organic matter levels to variations of climate-dependent carbon turnover parameters, which allowed us to compare the sensitivity of soil organic matter levels to net primary productivity of plant communities and plant debris decomposition rate constants across the range of soils in the European part of Russia. The results indicate that meadow steppes show the lowest sensitivity to variations of these parameters. In passing from meadow steppes to the northern taiga and to semideserts, the sensitivity increases. In general, soil organic matter levels of boreal forest ecosystems are about 2–3 times more sensitive to input and decomposition of plant debris than to decomposition of humus. In subboreal grassland ecosystems the sensitivity to humus decomposition increases and becomes closer to the degree of sensitivity shown by soil organic matter levels to variations of productivity and decomposition of plant debris. The proposed method may be useful for predicting the response of ecosystems to climatic change. Received: 1 December 1997     

EDTA Extraction of Heavy Metals from Different Soil Fractions and Synthetic Soils

A laboratory-prepared contaminated soil was partitioned into four fractions, namely carbonate, Fe/Mn oxides, organic matter and clay mineral, according to the form in which the heavy metal bound with soil constituents. Individual contaminated soil fractions and synthetic soils were prepared for the study of soil extraction using ethylenediaminetetraacetic acid (EDTA). The effect of contact time and EDTA concentration were evaluated for both individual soil fractions and synthetic soils. The extraction reached equilibrium rapidly, after about 30 min. A 0.01 M EDTA solution was less effective than a 0.05 M or a 0.10 M EDTA. EDTA was proved to be effective for metal removal from the four individual soil fractions and synthetic soils. In general, approximately 90% of metals were removed from synthetic soils by 0.10 M EDTA. EDTA extraction of Pb from a contaminated carbonate fraction was thought to be affected by the formation of lead carbonates. A simple equation based on the sum of the released heavy metal from the individual components is used to check if there are interactions among the different soil components when mixed. The estimated values agreed well with the experimentally measured results only for the 0.10 M EDTA system.     

St. John’s Wort Herbal Teas – Biological Potential and Chemometric Approach to Quality Control

Plant Foods for Human Nutrition - St. John’s wort has been used for centuries in traditional medicine of many cultures, and nowadays it is well-known as a clinically important antidepressant...