Extension of murine life span by overexpression of catalase targeted to mitochondria

To determine the role of reactive oxygen species in mammalian longevity, we generated transgenic mice that overexpress human catalase localized to the peroxisome, the nucleus, or mitochondria (MCAT). Median and maximum life spans were maximally increased (averages of 5 months and 5.5 months, respectively) in MCAT animals. Cardiac pathology and cataract development were delayed, oxidative damage was reduced, H2O2 production and H2O2-induced aconitase inactivation were attenuated, and the development of mitochondrial deletions was reduced. These results support the free radical theory of aging and reinforce the importance of mitochondria as a source of these radicals.     

Breeding potential of Belgian landraces of leek ( Allium ampeloprasum L. var. porrum)

Western Europe is the world's greatest leek producing and consuming region. Belgium is situated in the centre of Western Europe and can be considered as a genepool of landraces of leek. Although the commercial varieties nowadays take over the successes of Belgian landraces, this paper deals with the breeding potential of the Belgian landraces. Typing the Belgian landraces was done in an observation trial together with 50 cultivars. Clustering analysis revealed that 4 of the Belgian landraces were autumn types, 2 landraces were of the early winter type and another 12 landraces were ranged with 6 commercial varieties to form the most winterhardy group of leek. For the important characteristics leaf colour and senescence resistance, the Belgian landraces were better than most of the commercial varieties. Although, for economically more important characteristics shaft length and some disease resistance they scored low. Finally, in this trial, the Belgian landraces were high yielding, especially in the late season. But also in the early season (harvest in September and November) some Belgian landraces were in the top 10 for yield. At harvest in February 9 of the 10 best yielding winterleeks were Belgian landraces. This proves that the Belgian landraces were well adapted to the soil and climate of this region. This revised version was published online in July 2006 with corrections to the Cover Date.     

Components of resistance to Liriomyza trifolii in Chrysanthemum morifolium and Chrysanthemum pacificum

Summary In three experiments, Chrysanthemum morifolium Ramat. cultivars and C. pacificum Nakai, were exposed for four days to adult flies of Liriomyza trifolii (Burgess). The flies fed on all plants and laid eggs which were allowed to developed in a leafminer free greenhouse. Feeding level and oviposition varied between genotypes. The largest differences between entries were visible in the percentage of larvae that reached the pupal stage. In the most susceptible C. morifolium cultivar 97% of the larvae pupated against 1% in the most resistant cultivar Penny Lane. C. pacificum Nakai was also resistant with larval survival rates of 12%, 2% and 0% respectively in three consecutive experiments. Breeding prospects and areas for further study are discussed.     

α-Tomatine and other steroidal glycoalkaloids in fruits of tomato lines resistant to the glasshouse whitefly (Trialeurodes vaporariorum Westw.)

Summary The total steroidal alkaloid compositions of the mature-harvested fruits of the tomato cultivar Allround (Lycopersicon esculentum), of the species L. hirsutum glabratum, resistant to the glasshouse whitefly (Trialeurodes vaporariorum), and of four resistant lines were determined by capillary gas chromatography. The contents of -tomatine in the red-ripe fruits of Allround and in those of the lines were low (5 mg/kg fresh weight). The green-mature fruits of the wild species had a high content (3390 mg/kg fresh weight) of -tomatine. The total alkaloid profiles of Allround and of the lines were similar. Comparison of flame ionisation detector response with thermoionic detector response indicated that in addition to tomatidine, the aglycone of -tomatine, a small amount of one other steroidal alkaloid might be present in Allround and in the lines. The wild species contained five compounds which possibly are steroidal alkaloids.The safety level of -tomatine in tomatoes is discussed. It was concluded that, in respect of the glycoalkaloids of the mature-harvested fruits, the resistant tomato breeding lines are as safe for human cosumption as the standard cultivar.     

Cellular Impact of Metal Trace Elements in Terricolous Lichen Diploschistes muscorum (Scop.) R. Sant. – Identification of Oxidative Stress Biomarkers

The purpose of this research is to present toxic effects of some heavy metals (cadmium, lead and zinc) on lichen physiology. In the North of France, those metals are concentrated for example in industrial polluted soils near metallurgic plants and waste dumps. Our investigations were conducted on Diploschistes muscorum (Scop.) R. Sant, a terricolous lichen growing on previously quoted soils as well as on non-contaminated ones. Different stress parameters were investigated as potassium leakage – which is related to the loss of membrane integrity – and oxidative stress through following parameters: malondialdehyde (MDA), glutathione (GSH) and superoxide dismutase (SOD). It seems, therefore, that heavy metals induce oxidative stress in this lichen, in which we found membrane damage and enhancement of SOD activity and GSH concentrations. With regard to very high concentrations of Cd, Pb and Zn, a resistance involving antioxidant mechanisms limits the expected damage. Those mechanisms involve GSH, SOD as well as secondary metabolites, which have this resistance property. This study is a first step of investigation to use – in the future– physiological parameters as tool for environment assessment.     

Regional‐scale characterization of the geomorphic control of the spatial distribution of soil organic carbon in cropland

The heterogeneity of the spatial distribution of soil organic carbon (SOC) at the landscape scale is generally not considered in regional or national SOC dynamics models. In cropland this heterogeneity is controlled largely by topography, which influences the distribution of water, energy and sediments, and thus the SOC dynamics. Sediment redistribution rates have increased strongly since the mechanization of agriculture. The over‐simplification of landscape processes in regional models of C dynamics may add to the uncertainty in C balances. Therefore, a better characterization of the importance of landscape‐scale effects on the SOC distribution throughout a region is needed. This study characterized the relative importance of geomorphology in the SOC horizontal and vertical variability across croplands in the Belgian loess belt region. A large legacy dataset of soil horizons was exploited together with 147 recently sampled profiles. Mean SOC depth profiles for different soil types were compared. Various topographic attributes were computed from a digital elevation model, and their influence on SOC was quantified through simple linear models. Finally, SOC content was mapped at three depth layers through multiple linear models, and results were cross‐validated. The legacy dataset allowed identification of significant differences in the mean SOC profile according to texture, drainage or profile development classes. A clear relationship between SOC content and topographic attributes was demonstrated, but only for the recently sampled profiles. This may be explained by a substantial error in the location of the profiles of the legacy dataset. This study thus shows evidence that the major control of the vertical distribution of SOC is related to topography in a region where observed heterogeneities for other commonly involved factors are limited. However, the large amount of unexplained variability still limits the usefulness of the spatial prediction of SOC content, and suggests the importance of additional influencing factors.     

Psychological determinants of behaviors leading to occupational injuries and diseases in agriculture: a literature overview

Agriculture is one of the most hazardous occupational sectors, with a high prevalence of occupational injuries and work-related health problems. Most of these problems are caused by the interplay of human behavior and ergonomic factors and are thus preventable. Interventions to prevent occupational injuries and diseases among agricultural workers should aim to change risk behaviors and conditions by addressing specific behavioral determinants. To identify these factors, social cognitive models can be use that explain and predict health-related behavior. This study reviews the literature on the application of social cognitive models for the prevention of occupational injuries and diseases among agricultural workers. Studies are reviewed that apply the Health Belief Model, Theory of ReasonedAction, Theory of Planned Behavior, Transtheoretical Model of Change, or their subcomponents, to predict or change preventive behavior. Only a limited number of studies were found describing interventions that make use of these models, and those that do are often poorly documented with regard to the effect sizes and the explanatory or predictive value. It is concluded that the application of social cognitive models could significantly contribute to the effectiveness of preventive interventions in agriculture.     

Science and elephant management decisions in South Africa

Most conservation practitioners rely on experience-based information for management decisions. In South Africa, government policy thus directs managers to base decisions for elephant management on the best available scientific information. The reliance of their management decisions on science, however, is unknown. We interviewed 30 managers from small to large protected areas in South Africa to evaluate whether science underpinned strategic and applied management decisions regarding elephants. We also evaluated their perspectives on limitations to, and opportunities for, greater reliance on science. Twenty-nine managers valued science as a platform for their decisions. However, most managers based decisions on experience-based information. Only 28%, 30% and 8% of managers respectively developed objectives, identified issues and selected management methods on science-based information. Furthermore, only 30% selected a desired number of elephants, and 5% selected a population control method, according to science-based information. The probability of managers basing decisions on science-based information differed with management area size, tenure, planning timeframes and manager experience. However, except for experience, these relationships were weak, and overall an implementation gap between science and elephant management existed. Limitations for science to inform decisions included lack of relevance and application of science findings to respective management areas, and scientists’ attitudes and credibility. Opportunities included more site specific studies, better communication of, and easier access to scientific material. These opportunities could enable scientists to contribute more effectively to elephant management decisions and improve the reliance on science among the wider community of conservation practitioners in Africa.     

Liming Potential of Composts Applied To an Acid Oxisol in Burundi

The adverse effect of soil acidity on plant growth and yield, and the scarcity of commercial agricultural lime (CaCO₃) in Burundi necessitated a search for alternative liming materials. Thus, the liming potential of locally made composts was evaluated in a greenhouse experiment, using an acid Oxisol with sorghum (Sorghum vulgaris) as a test plant. Application rates were 10 g/kg (approximately 20 ton/ha) for the composts and 0, 0.85 and 1.70 g/kg for Verrundi lime. Results showed that the application of lime increased plant growth by reducing exchangeable Al, and by increasing soil pH and available P. So did the composts, which were more effective in correcting soil acidity when they were fresh and enriched with some nutrients during the composting process. Apparently, organic molecules produced by the composts helped to chelate and/or precipitate Al, making the soil more suitable for plant growth. Specifically, an application of 20 ton/ha of composts was equivalent to 0.6 - 1.7 ton CaCO₃/ha, depending on the compost quality.