Effect of salicylic acid treatment on tomato plant physiology and tolerance to potato virus X infection

Salicylic acid (SA) is an inducer of systemic acquired resistance (SAR) and could be a potential candidate in the control of plant virus diseases. In this study we assayed under controlled conditions the potential effect of three doses of exogenous SA treatment on tomato plants infected with Potato virus X (PVX) and measured their effects on: different physiological parameters (gas exchange, stable isotopes, chlorophyll content), the activation of secondary metabolism, viral accumulation and induction of the expression of pathogenesis-related proteins (PRs) such as ß-1, 3-glucanase (PR2) and chitinase (PR3). SA treatment increased the expression of PR2, the activity of phenylalanine ammonia lyase (PAL) and the concentration of antioxidant compounds at 7 days post-treatment. Earlier expression of PR3 compared to PR2 was observed. SA treatment delayed the detection of PVX by ELISA in uninoculated leaves of mechanically infected tomato plants. Although the effect of PVX infection on physiological parameters was weak, moderate SA treatments showed enhanced photosynthesis, particularly for infected plants. The results obtained confirm that SA promotes major changes in the induction of resistance in tomato plants and suggest that treatment with exogenous SA could be considered to reduce the infections caused by PVX.     

Distance to edges, edge contrast and landscape fragmentation: Interactions affecting farmland birds around forest plantations

Afforestation often causes direct habitat losses for farmland birds of conservation concern, but it is uncertain whether negative effects also extend significantly into adjacent open land. Information is thus required on how these species react to wooded edges, and how their responses are affected by edge and landscape characteristics. These issues were examined in Mediterranean arable farmland, using bird counts at 0, 100, 200, 300 and >300 m from oak, pine and eucalyptus edges, embedded in landscapes with variable amounts and spatial configurations of forest plantations. Bird diversity declined away from edges, including that of woodland, farmland and ground-nesting birds. Positive edge responses were also found for overall and woodland bird abundances, and for five of the nine most widespread and abundant species (Galerida larks, stonechat, linnet, goldfinch and corn bunting). Strong negative edge effects were only recorded for steppe birds, with reduced abundances near edges of calandra larks and short-toed larks, but not of little bustards and tawny pipits. Edge contrast affected the magnitude of edge effects, with a tendency for stronger responses to old and tall eucalyptus plantations (hard edges) than to young and short oak plantations (soft edges). There were also species-specific interactions between edge and fragmentation effects, with positive edge responses tending to be strongest in less fragmented landscapes, whereas steppe birds tended to increase faster away from edges and to reach the highest species richness and abundances in large arable patches. Results suggest that forest plantations may increase overall bird diversity and abundance in adjacent farmland, at the expenses of steppe birds of conservation concern. Clustering forest plantations in a few large patches and thus reducing the density of wooded edges at the landscape-scale might reduce such negative impacts.     

Effects of elevated temperature, elevated CO2 and fertilization on quality and subsequent decomposition of silver birch leaf litter

We examined the quality and decomposition of naturally abscised leaves of silver birch (Betula pendula) seedlings subjected to three different levels of fertilization under ambient and elevated levels of temperature and CO₂. At the end of the second growing season, the chemical composition of the litter collected from the seedlings was analyzed. Whole-leaf samples from pooled litter from each of the four replicates from each treatment were put in mesh bags and transferred to ambient climate in the field. The remaining mass of litter was measured by sampling bags in May and October throughout the four-year incubation period. Fertilization with all nutrients decreased the initial carbon and tannin contents of litter, and increased the proportion of the fast-decomposing fraction, but still fertilization slowed down the decomposition of this fraction. Initially, the estimated proportion of the fast-decomposing fraction was smallest in elevated CO₂ + temperature, and largest in ambient climate. During decomposition, elevated growth-temperature slowed down decomposition of the fast fraction under ambient CO₂ but increased it under elevated CO₂. The changes in litter decomposition rates found over four years were not very large. However, we conclude that the interactions of different factors lead to different results than if the factors had been studied separately, and future studies should take interactions into account.     

Granulocytic anaplasmosis in three dogs from Saskatoon,Saskatchewan

Three dogs from Saskatoon, Saskatchewan were diagnosed with acute granulocytic anaplasmosis. Fever, lethargy, inappetence, vomiting, diarrhea, and lameness were reported. Lymphopenia, thrombocytopenia, and splenomegaly were identified in all dogs. Inclusions were identified within the cytoplasm of blood neutrophils, and infection with Anaplasma phagocytophilum was confirmed by polymerase chain reaction.     

Monitoring of leptospirosis seroprevalence in a colony of captive collared peccaries (Tayassu tajacu) from the Peruvian Amazon

Leptospirosis, an endemic zoonoses, is maintained in the environment by several wildlife species in the Peruvian Amazon. In order to evaluate the possible role of collared peccaries (CP) in the maintenance this disease, two serological surveys of leptospirosis were performed and zootechnical parameters were monitored in a captive CP colony in an interval of 27 months. Total seroprevalence changed from 100% (n = 27) to 86.4% (n = 22), with reactions to a diversity of serogroups of zoonotic importance. Serological reactions to Leptospira licerasiae serogroup Iquitos, a new species recently identified locally and Leptospira interrogans serogroup Icterohaemorrhagiae were highly prevalent. The observation of leptospiral antibodies in both surveys, changes on serological reactions to different serogroups in large part of the herd and poor reproductive performances, provided an indication of the role of CP farms as a favourable environment for maintaining leptospirosis. Further research regarding the role of CP in the epidemiology of leptospirosis in the Peruvian Amazon is encouraged.     

Net requirements of calcium, magnesium, sodium, phosphorus, and potassium for growth of Nellore × Red Angus bulls, steers, and heifers

A comparative slaughter trial was conducted to assess the net requirements for gain of Ca, P, Na, K and Mg of bulls, steers and heifers of Nellore and Red Angus crossbreds. Twenty seven F1 Nellore and Red Angus crossbred calves (9 steers, 9 bulls, and 9 heifers), averaging 274 kg BW, were used. At the beginning of the trial, three animals from each gender were slaughtered to determine the initial body composition. The remaining 18 animals (3 animals of each gender) were randomly assigned to two treatments: fed 0.75 or 1.5% of BW of concentrate. The diets were based on corn silage and were isonitrogenous (2% N, DM). After three growing periods of 28 d, all animals were slaughtered. The cleaned gastrointestinal tract, organs, carcass, head, hide, tail, feet, and tissues were weighed to determine the empty BW (EBW). These parts were ground separately and subsampled for chemical analyses. The log of the contents of each mineral in the empty body was regressed on the log of the EBW to estimate the net requirement for each mineral per kg of empty body gain (EBG). There were no differences (P > 0.05) in the net requirements for growth of all macrominerals among genders. The equations of the pooled data of the net requirements for growth (g/kg EBG) were: 332.6 × EBW ^− 0.6367 for Ca, 112.1 × EBW ^− 0.5615 for P, 10.85 × EBW ^− 0.3992 for Na, 4.01 × EBW ^− 0.153 for K, and 3.589 × EBW ^− 0.462 for Mg. Our findings indicated that retained Ca and retained P were poorly related to the retained protein.     

Spacing of silver birch seedlings grown in containers of equal size affects their morphology and its variability

Silver birch (Betula pendula Roth) seedlings were grown individually in containers arranged in rows radiating from a central point (Nelder plot) at densities spanning the range from 207 to 891 plants m(-2). Height of one set of seedlings was measured at weekly intervals and additional seedlings were harvested each week for dry mass and leaf area measurements. Height and shoot:root dry mass ratio increased with plant density. Seedling-to-seedling variability in dry mass, but not height, increased with increasing plant density. The red to far-red (R:FR) photon ratio in horizontally propagated radiation decreased with increasing density, even when plant densities and leaf area index values were low. In a separate experiment, elongating internodes of seedlings were irradiated locally by red and far-red light emitting diodes and stem elongation measured. Far-red light markedly increased stem elongation, suggesting that changes in light quality sensed by growing internodes are involved in the observed responses to growth density.     

Optimization of the extraction of antioxidants from Dunaliella salina microalga by pressurized liquids

In this work, extraction of antioxidant compounds from Dunaliella salina microalga is optimized by combining pressurized liquid extraction (PLE) and experimental design (three-level factorial design) with three different solvents (hexane, ethanol, and water). Two main factors were considered, the extraction temperature (40, 100, and 160 degrees C) and the extraction time (5, 17.5, and 30 min). As response variables, the extraction yield (percent dry weight/initial weight) and the antioxidant activity of the extracts (determined using the TEAC method) were used. The parameters of the model were estimated by multiple linear regression. Results showed that the extraction temperature was the factor having the strongest influence (positive) on the two response variables. The best yields were obtained with ethanol at the higher extraction temperature and time tested. Besides, although hexane extracts provided the best antioxidant activity, ethanol extracts were also very active. The chemical characterization of ethanol extracts was carried out using HPLC-DAD, and attempts have been made to correlate their chemical composition with the antioxidant activity measured. Results pointed out that the extracts contained, besides all-trans-beta-carotene and isomers, several different minor carotenoids that seemed to make a contribution to the antioxidant activity of the extracts.     

Monitoring of moisture redistribution in multicomponent food systems by use of magnetic resonance imaging

Differences in water activity within multicomponent food systems inevitably lead to moisture (re)distribution phenomena, hence deteriorating textural quality during shelf life. Noninvasive assessment of moisture transport in such systems would promote mechanistic understanding and enable rational development of strategies to control migration. Magnetic resonance imaging (MRI) is an ideal candidate for such a measurement technique, but its use in systems with low-moisture components (e.g., cereal materials) is seriously hampered because of reduced transverse relaxation times. In this work, we report two MRI protocols for the noninvasive and quantitative assessment of moisture transport in multicomponent food products. The first protocol is suitable to study relatively slow (days/weeks) processes, whereas the second one is designed to study fast (hours) moisture transport. We have successfully applied this methodology to quantify moisture transport within multicomponent food systems, with adequate temporal and spatial resolution.