We conducted a seroepidemiological survey to determine the prevalence of caseous lymphadenitis (CLA) in goat herds in Minas Gerais state, Brazil. Serum samples were collected from goats (n = 676) from 108 rural properties in 2001, covering most of the sub-regions of this ca. 586,500 square kilometer state. Antibodies against Corynebacterium pseudotuberculosis secreted proteins were detected by an indirect enzyme-linked immunosorbent assay (ELISA). Most of the animals (78.9%) tested positive for CLA; 98% of flocks presented at least one seropositive animal. Goats managed under an extensive production system had a significantly higher seroprevalence of CLA than those in intensive and semi-intensive operations. The age distribution of the animals in the flocks affected the prevalence of this disease; however, goat breed did not. We found seropositivity against C. pseudotuberculosis to be highly prevalent in these Brazilian goat herds; consequently, appropriate management practices for the control of CLA should be implemented. 相似文献
The incorporation of biological control organisms in seeds may help control pathogens and improve seedling performance. The aim of this study was to determine the effects of biopriming bean seeds with Trichoderma spp. and Bacillus subtilis using physiological conditioning, suspensions of biological structures and film coating techniques. Biopriming treatments with suspensions of biological structures were performed using the commercial products Agrotrich plus® and Rhizoliptus®. Water restriction was achieved using a PDA?+?Manitol (?0.7?MPa) medium for both Trichoderma spp. and Bacillus subtilis. Fifty disinfected bean seeds were placed in each petri dish. When the first radicle protrusion appeared in a seed, the other seeds were removed and dried in the laboratory environment for 48?h. Film coating was performed with the addition of the Color Seed® (150?mL kg?1) polymer to a treatment solution containing either the Trichoderma spp. or the Rhizoliptus product. Seeds were dried for 48?h in the laboratory. Seeds were covered and treated with one or both organisms. Biopriming with spore or bacterial cell suspensions promoted bean seedling growth, and the other techniques were not required to potentiate these benefits. Covering the primed bean seeds reduced seed quality. Both Trichoderma spp. and Bacillus subtilis promote bean seedling growth, benefitting the seedling even after it becomes independent of the seed reserves. 相似文献
The reactive oxygen species (ROS) produced by neutrophils are involved in the pathogenesis of several diseases, for which the intake of antioxidants could benefit patients either as a prophylactic or therapeutic treatment. Propolis is among the known antioxidants, and its chemical composition may vary under the influence of seasonality, which may interfere in its biological properties. This work evaluates the role of seasonality on the production of some important compounds of propolis samples produced monthly from November 2001 through October 2002 as well as the effect of these samples on the oxidative metabolism of stimulated neutrophils, by using both luminol and lucigenin to produce chemiluminescence (CLlum and CLluc, respectively). The cytotoxicity of the most active extracts to neutrophils was also investigated. The inhibitory effect of the propolis samples varied significantly during the studied period for both assays (3.4 ± 1.1 to 16.0 ± 1.1 μg/mL for CLlum and 6.2 ± 2.0 to 30.0 ± 5.0 μg/mL for CLluc), which was also observed in the quantitative profile of the main analyzed compounds (aromadendrin-4′-methyl ether, artepillin C, and baccharin). This effect started to become more prominent during the fall and, among all the studied extracts, the one obtained in May displayed the highest inhibitory effect on CL production (3.4 ± 1.1 μg/mL for CLlum and 6.2 ± 2.0 μg/mL for CLluc). The HPLC qualitative profiles of the extracts of propolis samples were quite similar, but there was a huge variation in terms of quantitative profile. It seems that aromadendrin-4′-methyl ether and baccharin play an essential role in the antioxidant activity, while artepillin C is not very important for this effect. The extracts presenting the highest antioxidant activity were produced in May, June, and August, and they did not display cytotoxicity at 25 μg/mL; quercetin, used as control, was not toxic to neutrophils at 8.5 μg/mL. 相似文献
The increasing demand for renewable energy feedstock has raised interest in growing eucalypts for fuel wood production, which is achieved by establishing very dense plantations cut every 18–24 months. The high moisture content of fresh Eucalyptus may handicap cut-and-chip operations, and offers a unique opportunity for supply chains based on baling. Therefore, the Canadian-made BioBaler was tested in Brazil on a eucalypt energy plantation, as well as on the resprouts generated by a conventional pulpwood plantation after severe frost damage. The BioBaler coped well with both crops, achieving high productivity levels: 7.1 and 3.3 t h?1 in the energy plantation and the failed crop treatments, respectively. Harvesting cost was estimated at €13 t?1 and €26 t?1 for the energy plantation and the failed crop, respectively. Productivity and harvesting cost were comparable with those reported in previous studies conducted in other countries on similar crops. Productivity was directly proportional to field stocking. Future studies should test the machine on a wider range of work conditions and include bale extraction, storage, processing and transportation, in order to estimate an overall supply chain cost and allow direct comparison with alternative options. 相似文献
The reaeration coefficient (Ka) is an essential parameter to predict the dissolved-oxygen concentration in different aquatic ecosystems. The techniques applied to Ka estimates require considerable efforts, since measuring this coefficient is a laborious and expensive task. Thus, the use of predictive equations wherein Ka is found through hydraulic flow parameters is common. However, the available prediction equations lead to estimates often different from each other. A new predictive equation is addressed in the present study. The insertion of a dimensionless number resulting from the relation between the RMS (Root Mean Square) of the free-surface vertical velocity and the surface flow velocity is the great innovation of the study. The reaeration experiments and the surface vertical velocity mapping were performed in a circular hydraulic channel. The flow velocity varied from 0.25 to 0.64 m s?1, and depth varied from 0.09 to 0.15 m. The new equation led to more accurate results than the equations based on traditional hydraulic parameters such as the Reynolds and Froude numbers, mainly when it comes to Ka values higher than 40 day?1. The sensitivity analysis has shown that the new dimensionless number is the most sensitive parameter of the herein proposed predictive equation and that the influence from the Reynolds and Froude numbers on Ka weakens as turbulence gets more intense. 相似文献
In this study the helminthiasis and anthelmintic effectiveness in ewes and lambs were evaluated in a semiarid region of Brazil. Twelve sheep farms were investigated using semi-structured questionnaires and fecal egg count (FEC) reduction test was employed to analyze the profile of anthelmintic resistance. Groups of at least 10 animals with FEC ≥ 300 were selected. After 12 h of fasting, homogeneous groups of lambs or ewes were treated with albendazole, levamisole moxidectin, or oxfendazole and control groups were not treated. Feces were collected before treatments and 14 days after, and larvae genera were identified after cuprocultures in both periods. Extensive grazing was the predominant creation system, using hybrid Santa Ines animals. The separation by age was promoted in 75% of herds; however, maternity pickets there were only in three farms. The strategic treatments were performed only in 8.4% of sheep farms and 16.6% used the anthelmintic efficacy test and alternated anthelmintic classes after 1 year. The initial FEC means for lambs were significantly higher than ewe FEC averages. For lamb tests, moxidectin and levamisole showed higher efficacy (p ≤ 0.05) than benzimidazoles. For ewe tests, moxidectin and levamisole showed efficiencies >75%. Haemonchus spp. and Trichostrongylus spp. were the most frequent nematodes before treatments and the genus Haemonchus was the most prevalent after anthelmintic treatments (p < 0.05). Variations of anthelmintic susceptibility were observed for categories and herds evaluated, which emphasizes the importance of the effectiveness tests for the choice of anthelmintics for ewes and lambs. 相似文献
Silicon (Si) application, both via foliar application and via roots, may be promising to improve plant growth under different biotic or abiotic stresses. In the present study, we investigated whether application of Si can also mitigate the harmful effects of boron (B)‐related nutritional disorders, such as B deficiency, when the application of B is inefficient or insufficient, and B toxicity, when the soil presents high levels of B. This may enable producers to apply Si preventively, if there is a low availability of B in the environment or if B deficiency is induced during the growth season due to a water deficit reducing the plant's B absorption. The objective of this study was to investigate the influence of leaf and root Si application on alleviating the harmful effects of B deficiency and toxicity in cotton. Three experiments were carried out with cotton plants (Gossypium hirsutum cv. Bayer FM910®), using a soilless system. In a first experiment, we determined that highest plant Si concentrations were obtained with application of stabilized sodium and potassium silicate at concentrations of 0.8 g L?1 (foliar) and 0.056 g L?1 (roots). Experiment 2 indicated that the B concentrations in the nutrient solution associated with moderate B deficiency, sufficiency and moderate toxicity were 33.7, 83.6, and 130.5 µM B L?1, respectively. In Experiment 3 we evaluated the effect of optimum Si applications on the physiology and dry weight production of cotton plants subjected to B deficiency, sufficiency, and toxicity. Silicon mitigated the harmful effects of both B deficiency and toxicity by increasing whole‐plant biomass production and levels of chlorophyll a, chlorophyll b, and total chlorophyll, and reduced initial and maximum fluorescence, thereby improving the quantum efficiency of photosystem II. Collectively, these results indicate that the greatest benefit of Si in mitigating B deficiency occurred with foliar B application, while Si supplied via the nutrient solution was more effective against B toxicity. 相似文献
In Brazil, chemical control is one of the main tools to manage insect pests in wheat. However, this kind of management can impair the biological control provided by the predators Chrysoperla externa and Eriopis connexa. The present study evaluated the side effects on C. externa and E. connexa of 15 insecticides registered for wheat. Insecticides were sprayed on eggs and pupae via Potter tower at the maximum recommended dose. We evaluated the viability of eggs and pupae as well as the sub-lethal effects on fecundity and fertility of the adults emerged from treated pupae. The insecticides were classified according to the scale of toxicity proposed by IOBC. Regarding the eggs, the insecticide etofenprox was classified as slightly harmful (class 2) to C. externa. Imidacloprid + beta-cyfluthrin, diflubenzuron WG, thiamethoxam + lambda-cyhalothrin A and B, gamma-cyhalothrin, and etofenprox were also classified as slightly harmful (class 2) to E. connexa, while methomyl was classified as moderately harmful (class 3) for the eggs of the predator. The insecticide imidacloprid + beta-cyfluthrin was considered slightly harmful (class 2) to pupae of C. externa, while imidacloprid + beta-cyfluthrin, thiamethoxam + lambda-cyhalothrin A and B, and lufenuron were classified as slightly harmful (class 2) to the pupae of E. connexa. The insecticides beta-cyfluthrin, diflubenzuron SC, lambda-cyhalothrin, permethrin, thiamethoxam, triflumuron, and zeta-cypermethrin were harmless to eggs and pupae of both predators and should therefore be prioritized in the control of insect pests in wheat, thus preserving the natural biological control provided by C. externa and E. connexa. 相似文献
The cover image, by Josemar Foresti et al., is based on the Research Article Economic injury levels and economic thresholds for Leptoglossus zonatus (Dallas) (Hemiptera: Coreidae) infesting seed maize, DOI: 10.1002/ps.4671 . Photo Credit: Josemar Foresti.
