Bekämpfung der wichtigsten Schädlinge der brasilianischen Landwirtschaft

Ohne ZusammenfassungDie Autoren sprechen Dr. Otto Schubart, Biologen der Estação Experimental de Biologia e Piscicultura, Pirassununga, Estado de São Paulo, ihren Dank aus für die Übersetzung dieses Artikels ins Deutsche, sowie Dr. Francisco A. Menezes Mariconi vom Instituto Biológico in São Paulo für verschiedene Ratschläge.     

Antiplatelet and Anticoagulant Effects of Diterpenes Isolated from the Marine Alga,Dictyota menstrualis

Cardiovascular diseases represent a major cause of disability and death worldwide. Therapeutics are available, but they often have unsatisfactory results and may produce side effects. Alternative treatments based on the use of natural products have been extensively investigated, because of their low toxicity and side effects. Marine organisms are prime candidates for such products, as they are sources of numerous and complex substances with ecological and pharmacological effects. In this work, we investigated, through in vitro experiments, the effects of three diterpenes (pachydictyol A, isopachydictyol A and dichotomanol) from the Brazilian marine alga, Dictyota menstrualis, on platelet aggregation and plasma coagulation. Results showed that dichotomanol inhibited ADP- or collagen-induced aggregation of platelet-rich plasma (PRP), but failed to inhibit washed platelets (WP). In contrast, pachydictyol A and isopachydictyol A failed to inhibit the aggregation of PRP, but inhibited WP aggregation induced by collagen or thrombin. These diterpenes also inhibited coagulation analyzed by the prothrombin time and activated partial thromboplastin time and on commercial fibrinogen. Moreover, diterpenes inhibited the catalytic activity of thrombin. Theoretical studies using the Osiris Property Explorer software showed that diterpenes have low theoretical toxicity profiles and a drug-score similar to commercial anticoagulant drugs. In conclusion, these diterpenes are promising candidates for use in anticoagulant therapy, and this study also highlights the biotechnological potential of oceans and the importance of bioprospecting to develop medicines.     

Postharvest water relations in cut rose cultivars with contrasting sensitivity to high relative air humidity during growth

A constant high relative air humidity (RH) during cultivation can strongly reduce the vase life in some cut rose cultivars. We studied three contrasting cultivars in their tolerance to high RH in order to analyse in detail the water relations during postharvest and better understand this genotypic variation. Plants were grown at moderate (60%) and high (95%) RH, and cut flowers were placed in water immediately after cutting. Flowers of cv. Pink Prophyta grown at high RH did not open throughout vase life, while flower opening of cvs. Frisco and Dream was not affected by preharvest RH. Cultivation at high RH resulted in about 80% shorter vase life in Pink Prophyta, whereas in Dream and Frisco the negative effect was considerably smaller (15 and 9% shorter vase life, respectively). The shorter vase life and reduced flower opening of cut roses grown at high RH was due to a higher rate of transpiration both in the light and dark periods. It was found that the leaves of Pink Prophyta grown at high RH could partly close their stomata upon lowering of the water potential or when flower stalks were fed with abscisic acid, but stomata remained far more open than in leaves grown at moderate RH. The RH during cultivation did not affect stem hydraulic conductivity and its recovery after air emboli induction. Preventing vascular occlusion largely alleviated the high-cultivation-RH effect on vase life and flower opening, showing that the effect of high-cultivation-RH becomes only important if water uptake is limited.     

Mid-infrared absorption properties of green wood

There is a lack of quantitative data on the penetration depth and the amount of energy absorbed by green wood under infrared (IR) radiation. This lack of knowledge is a potential barrier to the development of IR heating as an alternative to soaking as a means of warming logs prior to peeling in the manufacture of plywood. Experimental measurements of normal hemispherical spectral reflectance and transmittance over the range 550–5,500 cm^?1 wavenumbers on four wood species, beech, birch, Douglas-fir and spruce have brought new knowledge on mid-infrared absorption properties of green wood and removed some uncertainties. For instance, it is not possible to deliver energy deeper than up to 0.3 mm below the wood surface because 70–90 % of all incident IR radiation on the wood surface is absorbed in this layer. Some wood features, such as surface quality, the presence of knots and of free water in wood (the latter two having a more significant effect) influence the amount of energy absorbed. These results illustrate that IR radiation can heat the surface layers, but then heat penetrates deeper into the inside layers of wood by conduction.     

Productivity and nutritive value of Brachiaria decumbens and performance of dairy heifers in a long‐term silvopastoral system

Silvopastoral system (SPS) has been suggested to ensure sustainability in animal production systems in tropical ecosystems. The objective of this study was to evaluate the productive and nutritive value traits of Brachiaria decumbens and performance of dairy heifers in SPS and open pasture (OP) during the summer and autumn of two consecutive years in the SPS and OP (17th and 18th years after establishment). Experimental design was a randomized complete block with two treatments (SPS and OP) and three replications in subdivided plots with repeated measures in time. There was reduction in the tiller population density, total and green forage mass, and total and green forage bulk density in the SPS when compared to the OP in the summer. In the autumn, no difference was observed between the systems. Shading in SPS increased crude protein content of the grass pasture by 25% and 33% when compared to the OP during the first and second experimental years, respectively, and reduced neutral detergent fibre content. However, it did not change acid detergent fibre or lignin content. OP provided higher stocking rate and weight gain per area than the SPS. Average daily gain was higher in the OP in the second experimental year. Severe shading conditions should be avoided, because in the long ‐ term they may threaten the persistence and sustainability of pasture in the SPS. It is recommended to plant a low density of trees or implement management strategies of the tree component by either thinning or pruning over the years after planting.     

Structural Analysis of Tillandsia usneoides L. Exposed to Air Pollutants in São Paulo City–Brazil

Bioindicators plants are important for the evaluation of air quality and Tillandsia usneoides L., an atmospheric epiphyte bromeliad, has been used for this purpose. The present study aims at evaluate the structural pattern of the leaf of this species when exposed to urban air pollutants, and determining whether the leaves present structural parameters that could be used as indicators of such pollutants. Samples of T. usneoides were exposed in São Paulo, the biggest city of Brazil, for 8, 16 and 24 weeks, and compared with others kept in a rural area. The urban pollution of São Paulo affected the structure of the leaves of T. usneoides causing alterations, especially in the scales, density of stomata and epidermis thickness. Qualitative alterations in the mesophyll were not observed in plants exposed at the polluted sites. These structural characteristics of T. usneoides seem to account for its high tolerance to heavy metal accumulation. The percentage of anomalous scales may potentially be used as an alternative bioindicator parameter.     

Spoligotype diversity of Mycobacterium bovis and Mycobacterium caprae animal isolates

The genetic diversity of 283 Mycobacterium bovis (M. bovis) and 10 Mycobacterium caprae (M. caprae) strains, isolated between 2002 and 2007 from cattle, goat, red deer and wild boar from six different geographical regions of Portugal was investigated by spoligotyping. The technique showed a good discriminatory power (Hunter-Gaston Index, h=0.9) for the strains, revealing 29 different patterns. One pattern (SB0121) was clearly predominant, accounting for 26.3% of the isolates; ten patterns, representing 20.7% of the isolates, had never been reported previously. Multiple spoligotypes were detected in thirteen cattle and one goat herd, most of which were found in beef cattle and extensive management regions, suggesting different infection sources. With the exception of two spoligotypes, those in wildlife species were also found in domestic species.     

Strategies of the control of an outbreak of leptospiral infection in dairy cattle in Northeastern Brazil

The aim of the present study was to describe the strategies of the control of an outbreak of leptospiral infection in dairy cattle in Maranhão State, Northeastern Brazil. In the period from January to July 2015, 18 (17%) out of 106 cows presented abortion, six (5.7%) stillbirth, and 12 (11.3%) repeated estrus, totaling 24 animals with reproductive problems. The diagnosis of leptospirosis was based on serology (microscopic agglutination test—MAT), bacteriological culture, and polymerase chain reaction (PCR). Antibiotic therapy, vaccination protocols, and changes in management practices were suggested as control measures. Of all animals on the farm (n?=?280), 136 (48.6%) were seropositive for at least one serovar of Leptospira sp. No pure leptospiral culture was obtained. Eight of the animals with reproductive problems yielded positive PCR results (vaginal fluid of seven animals and urine and vaginal fluid of one animal). Genetic sequencing of a vaginal fluid/urine PCR-positive sample revealed Leptospira borgpetersenii. One year after the adoption of control measures, no reproductive problems were observed. Thus, leptospirosis probably caused the reproductive failures in the herd, and the control and prevention measures implemented were efficient in controlling the disease.

     

Comparison of the intravenous and intravaginal route of oxytocin administration for cervical dilation protocol and non‐surgical embryo recovery in oestrous‐induced Santa Inês ewes

This study compared the effects of intravaginal and intravenous routes of oxytocin (OT) administration in 46 oestrous‐induced Santa Inês ewes (6‐day treatment with progestin‐releasing intravaginal sponges and a single injection of 200 IU of eCG at the time of sponge removal) that underwent transcervical embryo recovery 6–7 days after oestrous onset and mating. All ewes received 37.5 μg of d‐cloprostenol via latero‐vulvar route, and 1 mg of oestradiol benzoate i.m. 16 hr before and 50 IU of OT 20 min before non‐surgical embryo recovery (NSER), with OT being administered intravenously (n = 21) or intravaginally (n = 21). An overall oestrous response was 95.6% (44/46), and adequate cervical retraction could be accomplished in 78.6% (33/42) of ewes. The percentage of successful NSER procedures was 57% (24/42) or 72.7% (24/33) of animals with sufficient cervical retraction. The duration of NSER procedure averaged 28 min (range: 17–40 min) and ~96% of flushing fluid could be recovered (range: 85%–100%). Out of 18 ewes that could not undergo NSER, 12 (66.6%) presented various anatomical barriers, whilst the other 33.4% did not present these barriers and still could not be traversed. Excluding the ewes with those anatomical features, the overall success rate of NSER was 80% (24/30). The route of OT administration had no effect on NSER efficiency or the ease with which transcervical embryo flushing was performed. Both routes of OT administration can be used for cervical dilation protocol. Discarding ewes with anatomical features precluding cervical penetration is highly recommended to increase the efficacy of NSER in sheep.