Effect of fertilizers, lime, and inoculation with rhizobia and mycorrhizal fungi on the growth of four leguminous tree species in a low-fertility soil

The aim of this study was to evaluate the effects of lime, fertilizers, mycorrhizal fungi, and selected rhizobia strains on the growth of four woody legume species, Albizia lebbeck (L.) Benth., Enterolobium contortisiliquum (Vell.) Morong., Leucaena leucocephala (Lam.) de Wit, and Sesbania virgata (Cav.) Pers. in a low-fertility soil. The experiment was conducted under greenhouse condition in plastic pots (4 kg). Eight treatments and eight replicates per treatment were performed in a completely randomized design. The treatments were: (1) complete treatment (C) (NPK fertilization?+?micronutrients?+?liming?+?MR that is inoculation with mycorrhizal fungi and rhizobia); (2) C minus N (C???N that is as C without the addition of N); (3) C???N???M (as C???N without inoculation with arbuscular mycorrhizal fungi (AMF)); (4) C???N??R (as C???N without inoculation of rhizobia); (5) C???N???liming (as C???N without liming); (6) C???N???micro (as C???N without addition of micronutrients); (7) C???N???P (as C???N without addition of P); (8) control without fertilization, liming, and without inoculation with AMF and rhizobia. After 4 months of growth, we determined the yield of individual plants, nodulation, mycorrhizal colonization, and nutrient contents. Phosphorus was the most limiting nutrient for plant growth, followed by nitrogen. L. leucocephala and S. virgata had the most robust response to the addition of micronutrients and liming, showing an increase in nutrient content, plant height, and root and shoot dry matter. When compared to the single inoculation, the dual inoculation increased growth of all plants, except that of A. lebbeck, which did not respond to either rhizobia or mycorrhizal fungi inoculation.     

Molecular typing of Mycobacterium bovis isolates from south-east Brazil by spoligotyping and RFLP

The identification of 163 strains of Mycobacterium bovis by polymerase chain reaction (PCR) and microbiological tests was carried out on 252 tuberculous-like lesions (TLLs) collected from slaughtered cattle in south-east Brazil. This study compared the usefulness of three genotyping techniques, IS6110-restriction fragment length polymorphism (RFLP), polymorphic guanine-cytosine-rich sequence (PGRS)-RFLP and direct repeat (DR)-spoligotyping, as applied to M. bovis isolates. Based on IS6110-RFLP genotyping we selected a group of 23 isolates containing more than one IS6110 copy, along with 16 samples containing one IS6110 copy from different geographical areas, evenly distributed among dairy (eight) and beef cattle (eight). These selected isolates were analysed by PGRS-RFLP and DR-spoligotyping genotyping. Dairy cattle (17%) display a higher frequency of multiple IS6110 copies than beef cattle (10%). A comparison between the genotype data obtained fails to show a correlation between the main clusters found by the three techniques. However, the clustering of each genotyping procedure revealed that the majority of strains are closely related. The RFLP-PGRS patterns showed a sizable group (20.5%) containing a 5.5 kb fragment and the predominant spoligotype is similar to that from the BCG vaccine strain. Unexpectedly, four strains (2.4%) showed drug resistance to 0.2 microg/ml isoniazid and 20 microg/ml ethionamide, but none of them was resistant to rifampicin or other antibiotics tested.     

Molecular Typing of Mycobacterium bovis Isolates from South‐east Brazil by Spoligotyping and RFLP

The identification of 163 strains of Mycobacterium bovis by polymerase chain reaction (PCR) and microbiological tests was carried out on 252 tuberculous‐like lesions (TLLs) collected from slaughtered cattle in south‐east Brazil. This study compared the usefulness of three genotyping techniques, IS6110‐restriction fragment length polymorphism (RFLP), polymorphic guanine‐cytosine‐rich sequence (PGRS)‐RFLP and direct repeat (DR)‐spoligotyping, as applied to M. bovis isolates. Based on IS6110‐RFLP genotyping we selected a group of 23 isolates containing more than one IS6110 copy, along with 16 samples containing one IS6110 copy from different geographical areas, evenly distributed among dairy (eight) and beef cattle (eight). These selected isolates were analysed by PGRS‐RFLP and DR‐spoligotyping genotyping. Dairy cattle (17%) display a higher frequency of multiple IS6110 copies than beef cattle (10%). A comparison between the genotype data obtained fails to show a correlation between the main clusters found by the three techniques. However, the clustering of each genotyping procedure revealed that the majority of strains are closely related. The RFLP‐PGRS patterns showed a sizable group (20.5%) containing a 5.5 kb fragment and the predominant spoligotype is similar to that from the BCG vaccine strain. Unexpectedly, four strains (2.4%) showed drug resistance to 0.2 μg/ml isoniazid and 20 μg/ml ethionamide, but none of them was resistant to rifampicin or other antibiotics tested.     

Invasive tilapia juveniles are associated with degraded river habitats

• 1. Invasions are a main concern for conservationists. Identification of causes that raise or promote an invader's success is one of the first steps for preventing and/or fighting against invasions.
• 2. In the Brazilian River Paraiba do Sul, juveniles of invasive tilapia Oreochromis niloticus were detected associated with degraded habitats (mainly pollution from various sources). The relative abundance of juveniles of the competitor native species pearl cichlid Geophagus brasiliensis, morphologically and ecologically very similar, was negatively associated with habitat degradation.
• 3. A species‐specific molecular marker was employed to permit unambiguous identification of these small juveniles (2–3 cm long), which represent the most vulnerable life stage of both species.
• 4. It is suggested that adaptation to degraded habitats is one of the characteristics of invasive species, and consequently habitat conservation and restoration may help to prevent fish invasions.

Copyright © 2008 John Wiley & Sons, Ltd.     

Modelling the impact of agricultural abandonment and wildfires on vertebrate diversity in Mediterranean Europe

Agricultural land abandonment, widespread in the Mediterranean, is leading to a recovery of scrubland and forests which are replacing open habitats and increasing wildfire events. Using published data, we modelled the global and regional impact of abandonment and wildfires on 554 species of terrestrial vertebrates occurring in Mediterranean Europe. For all groups except amphibians, open habitats or farmland sustained higher species richness. Open habitats showed regional differences in their conservation value, western areas being particularly important for birds and amphibians and eastern areas for reptiles. Scrublands hosted fewer species than open habitats, farmland and forest, but sustained several endemic birds and mammals. The greater species richness of forests was mostly due to species widespread in Europe. Wildfires promote scrubland expansion in detriment of forest; because more species are associated to eastern forests, fire is predicted to affect more seriously this region. Scrubland conservation value was found to be highest in the west, where fire might have a positive impact. Fire regime, however, plays a crucial role. Although large fires have a negative impact, small-scale fires may favour biodiversity in abandoned areas. Due to the intrinsic difficulty in managing abandoned land to preserve the original Mediterranean vertebrate diversity, the best option to achieve this goal is the development of policies designed to make farmers and traditional farmland survive.     

Effect of Proofing Time and Wheat Flour Strength on Bleaching,Sensory Characteristics,and Volume of French Breads with Added Soybean Lipoxygenase

Soybean lipoxygenase addition in wheat bread doughs is widely used to improve the crumb color and rheology but little is known about the variability of the activity of lipoxygenase under diverse breadmaking conditions. Thus the objective of this study was to evaluate how soybean lipoxygenase can affect bleaching, volume, and sensory characteristics of French breads when proofing time and wheat flour strength varies. A 3-factor Box-Behnken design was used in this study containing one block and three independent variables or factors designated by exogenous lipoxygenase activity (x₁ = 0–71 unit/μg of protein), wheat flour deformation energy (x₂ = 231–258 × 10^–4 J), and proofing time (x₃ = 2–6 hr). Breads were randomly prepared and all assays were repeated three times. Specific volume (from 5.8 ± 0.4 to 9.9 ± 0.4 cm³/g), sensory quality (from 5.2 ± 0.8 to 8.3 ± 0.6), and yellow hue (from 12.6 ± 0.5 to 16.2 ± 0.3) significantly changed (P < 0.01) among the treatments. Specific volume of the breads increased with higher values of wheat flour strength and proofing time (ŷ_vs = 7.5 + 0.9 x₂ + 1.2 x₃ +0.5 x₂x₃). Sensory quality improved at higher values of wheat flour strength and shorter proofing time (ŷ_sq = 7.8 + 0.7 x₂ – 0.2 x₃ – 0.4 x₂² – 0.6x₃² + 0.5 x₂x₃), while lower and more desirable values of yellow hue were achieved at longer proofing time, higher activity of lipoxygenase, and using stronger wheat flours (ŷ_b = 13.7 – 1.2 x₁ – 0.5 x₂ – 0.2 x₃ + 1.0 x₁² – 0.3 x₁x₂). All regression models showed a good fitness to the experimental data (lack-of-fit P > 0.05) and the difference between predicted and observed values were also not significant (P < 0.05). Our results suggested that proofing time and wheat flour strength have a greater effect on volume and sensory quality of French breads than soybean lipoxygenase. However, the bleaching effect of this enzyme showed positive interaction with proofing time and wheat flour strength, suggesting its application even when strong wheat flours are used for the manufacture of French breads.     

Effect of Temperature on Texture of Corn Tortilla With and Without Antistaling Agents

Tortilla stiffening should occur between ‐23 to 57°C, showing a maximum rate near the midpoint of this range (17°C). Starch recrystallization below the glass transition temperature (T_g = ‐23°C) in corn tortillas is minimal due to lack of molecular mobility. The objective of this study was to determine the effect of storage temperature (‐20 to 21°C) on the stiffening rate of corn tortillas with or without additives (carboxy‐methylcellulose [CMC] and maltogenic amylase). Tortilla pliability, stiffness, and energy dissipated obtained by stress relaxation, and amylopectin recrystallization determined by differential scanning calorimetry (DSC) showed a second‐order polynomial relationship with temperature. Tortillas became stiff faster during refrigerated storage (3–10°C). Adding 0.25% CMC and 1,650 AU of amylase maintained tortilla softness and flexibility, both at room temperature and under refrigeration for at least three weeks.