Use of Agrobacterium tumefaciens-mediated transformation for the inactivation of pectinase genes in Colletotrichum lindemuthianum

European Journal of Plant Pathology - The fungus Colletotrichum lindemuthianum has genes that encode different enzymes involved in plant cell wall degradation such as pectinases, which are...     

Natural occurrence of Beauveria bassiana on adults of the invasive mango seed weevil Sternochetus mangiferae (Coleoptera: Curculionidae) in Brazil

Journal of Plant Diseases and Protection - The mango seed weevil Sternochetus mangiferae (Fabricius) (Coleoptera: Curculionidae) was detected in Brazil in 2014, becoming a potential threat to mango...     

Rapid and extensive surface changes near Titan's equator: evidence of April showers

Although there is evidence that liquids have flowed on the surface at Titan's equator in the past, to date, liquids have only been confirmed on the surface at polar latitudes, and the vast expanses of dunes that dominate Titan's equatorial regions require a predominantly arid climate. We report the detection by Cassini's Imaging Science Subsystem of a large low-latitude cloud system early in Titan's northern spring and extensive surface changes (spanning more than 500,000 square kilometers) in the wake of this storm. The changes are most consistent with widespread methane rainfall reaching the surface, which suggests that the dry channels observed at Titan's low latitudes are carved by seasonal precipitation.     

Assessing the use of erosion modeling to support payment for environmental services programs

Purpose

Payment for environmental services (PES) has assumed increasing importance in discussions about sustainable development strategies. Many of the PES programs are based on water erosion control and the corresponding environmental and economic benefits generated in the basins where they are implemented. The main objective of this study was to show how erosion susceptibility models can support PES programs.

Materials and methods

The application of the Universal Soil Loss Equation (USLE) in the Sarandi Experimental River Basin (32.7 km²), located in the Federal District, Brazil, was used as a study case. Then a scheme for organizing knowledge about ecosystem services related to erosion control and water resources was performed. Considering the generated scheme, the USLE results, the land use map, and the water use in the region, we evaluated how erosion modeling could support PES programs.

Results and discussion

The results show that a large part of the study basin (90%) presents “low” susceptibility to erosion, which is significant in terms of the use and conservation of ecosystem services, as well as being a limitation regarding the need for the implantation of PES programs for erosion control. Incentives for maintaining the natural vegetation in areas with higher erosion susceptibility have the greatest potential to justify PES programs in the study basin, and the sanitation company is the potential payer for erosion control in the Sarandi River Basin.

Conclusions

The application of the USLE in a spatially distributed form proved to be an important support tool for land management and the implementation of PES policies.     

Antioxidant and antiproliferative activities of heterofucans from the seaweed Sargassum filipendula

Fucan is a term used to denominate a type of polysaccharide which contains substantial percentages of l-fucose and sulfate ester groups. We obtained five heterofucans from Sargassum filipendula by proteolytic digestion followed by sequential acetone precipitation. These heterofucans are composed mainly of fucose, glucose, glucuronic acid, galactose and sulfate. These fucans did not show anticoagulant activity in PT and aPTT tests. Their antioxidant activity was evaluated using the follow tests; total antioxidant capacity, scavenging hydroxyl and superoxide radicals, reducing power and ferrous ion [Fe(II)] chelating. All heterofucans displayed considerable activity, especially SF-1.0v which showed the most significant antioxidant potential with 90.7 ascorbic acid equivalents in a total antioxidant capacity test and similar activity when compared with vitamin C in a reducing power assay. The fucan antiproliferative activity was performed with HeLa, PC3 and HepG2 cells using MTT test. In all tested conditions the heterofucans exhibited a dose-dependent effect. The strongest inhibition was observed in HeLa cells, where SF-1.0 and SF-1.5 exhibited considerable activity with an IC50 value of 15.69 and 13.83 μM, respectively. These results clearly indicate the beneficial effect of S. filipendula polysaccharides as antiproliferative and antioxidant. Further purification steps and additional studies on structural features as well as in vivo experiments are needed to test the viability of their use as therapeutic agents.     

Tobacco harvest phase is critical to runoff and soil loss in conventional tillage system

Soil erosion in tobacco (Nicotiana tabacum) cultivation has been reported in recent years around the world. Moreover, studies also demonstrated total soil loss during cultivation. In this study, we proposed an assessment of loss of water and soil during the phases of tobacco cultivation. The tobacco cultivation cycle is approximately 180 days in Southern Brazil. We divided this period into 6 phases from planting (September) to the end of the harvest. During the phases, there were variations in soil management, which may indicate different rates of water and soil loss. Gerlach gutters were used to mediate soil and water loss. At each phase of cultivation, we also measured the surface roughness of the soil, water retention, soil exposure, trampling, soil resistance and soil bulk. Our results show that during cultivation the water and soil loss were 10.2% and 62.7 Mg ha⁻¹, respectively. However, the variation of activities during tobacco cultivation indicates different rates of water and soil loss. In the first three phases (90 days after planting), the surface roughness remained high (~19.2%) due to the soil turning, thus reducing the loss of water and soil despite little ground surface coverage. The soil tillage is stopped when the harvest of tobacco begins 120 days after planting. During the harvest, there was an increase in daily activities in the tobacco field, as the leaves were harvested every week, thus reducing soil roughness (~6.8%) and increasing soil density and strength. These conditions increased the rate of soil erosion during harvest. Therefore, the harvest phase is critical to runoff and soil loss.     

Serological and molecular evidence of hepatitis E virus in swine in Brazil

Active hepatitis E virus (HEV) infections in two Brazilian swine herds were investigated. In study 1, 26 piglets born to five anti-HEV positive sows were monitored from birth to post-partum week 22. Serum samples were screened for the detection of anti-HEV antibodies and a nested RT-PCR used to examine the HEV genome. Passive transfer of immunity was confirmed. At week 22, 23/26 (88.4%) of the piglets had seroconverted. Genome amplification was achieved in a feces pool from one holding pen and in one serum sample, both from 13-week-old animals. Histology was suggestive of a potential HEV infection. In the second study, 47 piglets born to six anti-HEV-positive sows were monitored after weaning. Seroconversion was determined in eight animals at 6-8 weeks of age. HEV RNA was detected in two pools from a holding pen for 12-16-week-old animals. Brazilian isolates were classified as genotype 3. This is the first molecular evidence of HEV infection in Brazilian pig herds.     

Determination of the More Adequate Modified Agglutination Test Cut‐off for Serodiagnosis of Toxoplasma gondii Infection in Sheep

Toxoplasmosis is one of the most common food borne disease world‐wide. Among food animals, sheep seems to having higher prevalence of Toxoplasma gondii infection. However, there is no consensus about the best cut‐off for serodiagnosis in sheep. To estimate the more adequate cut‐off value of Modified Agglutination Test (MAT) for serodiagnosis in sheep, a commercial ELISA kit was used as a golden standard. Evaluation of the optimal sensitivity and specificity was calculated using Youden’s J‐statistics. Values obtained were used to estimate the prevalence of sheep toxoplasmosis. One thousand four hundred and sixty seven blood samples were collected randomly from 160 farms from northern Portugal, representing approximately 10% of the ovine population from the region. All sera were tested for anti‐T. gondii antibodies using the MAT. One hundred nine sheep (7.4%) presented a MAT titer ≥1 : 80; 45 (3.0%) a MAT titer of 1 : 40; 97 (6.6%) a MAT titer of 1 : 20 and 1216 (83.0%) a MAT titer ≤1 : 20. The best Youden’s J‐statistic was obtained at 1 : 20 titer (0.752), with 86.15% of sensitivity and 89.09% of specificity with negative and positive predictive values of 90.32% and 84.48% respectively, suggesting that the 1 : 20 was the most appropriate cut‐off for serodiagnosis of toxoplasmosis in sheep. Assuming this cut‐off, the prevalence of toxoplasmosis in the studied population was 17.1% and 92 (57.5%) of the 160 studied flocks having one or more positive sheep. Those results indicate that toxoplasmosis in Portugal should be considered in the differential diagnosis of abortions in sheep and neurological signs in lambs. Furthermore, while Portugal produces ovine meat for internal consumption and for exportation, isolation of T. gondii from ovine meat and further characterization of the isolates will be needed to understand the risk that ovine toxoplasmosis may represent for human health.     

Fish and mussels: Importance of fish for freshwater mussel conservation

Co‐extinctions are increasingly recognized as one of the major processes leading to the global biodiversity crisis, but there is still limited scientific evidence on the magnitude of potential impacts and causal mechanisms responsible for the decline of affiliate (dependent) species. Freshwater mussels (Bivalvia, Unionida), one of the most threatened faunal groups on Earth, need to pass through a parasitic larval (glochidia) phase using fishes as hosts to complete their life cycle. Here, we provide a synthesis of published evidence on the fish–mussel relationship to explore possible patterns in co‐extinction risk and discuss the main threats affecting this interaction. We retrieved 205 publications until December 2015, most of which were performed in North America, completed under laboratory conditions and were aimed at characterizing the life cycle and/or determining the suitable fish hosts for freshwater mussels. Mussel species were reported to infest between one and 53 fish species, with some fish families (e.g., Cyprinidae and Percidae) being used more often as hosts than others. No relationship was found between the breadth of host use and the extinction risk of freshwater mussels. Very few studies focused on threats affecting the fish–mussel relationship, a knowledge gap that may impair the application of future conservation measures. Here, we identify a variety of threats that may negatively affect fish species, document and discuss the concomitant impacts on freshwater mussels, and suggest directions for future studies.     

Growth,mortality and reproductive traits of diploid and triploid Pacific oysters (Crassostrea gigas,THUNBERG, 1793) in Southern Brazil

This work aimed to evaluate the whole weight (g), shell height (mm), mortality (%) and reproductive aspects (condition index and histology) of triploid (3N) Pacific oysters (Crassostrea gigas) cultivated in southern Brazil. To accomplish this, a comparative experiment was performed with a diploid (2N) control group in two cultivation sites on Santa Catarina Island: North Bay (NB) and South Bay (SB). Whole weight, height and cumulative mortality were evaluated monthly for eight months and condition index (CI) for six months. Histological analysis was performed every two weeks for four months to investigate reproductive aspects. At the end of the experiment, whole weight and height were similar for 3N and 2N oysters. However, while more growth in whole weight and height was observed in the initial phase of cultivation in NB, such growth was not detected in SB until intermediate and final grow‐out phase. At harvest, cumulative mortality in 3N oysters was similar that in 2N oysters. The results suggest that diploid and triploid oysters grown in southern Brazil have similar developmental patterns based on whole weight and height, as well as reproductive cycle. In addition, cultivation sites have more influence on growth and mortality than ploidy levels.