Induction d'un cytochrome du type P450 et de péroxydase durant la survie du tubercule de pomme de terre

During the ageing of potato tubers, a labile cytochrome of the P₄₅₀ type appears, always accompanied by the presence of P₄₂₀-type pigment. This induction of P₄₅₀ coincides with an increase in peroxidase activity together with an increase in the amount of cytochrome b₅.     

Heat shock proteins as potential targets in the therapy of inflammatory arthritis

Whether heat shock proteins (hsp) will be therapeutic targets in arthritis depends on their role in pathogenesis. In this article, three possibilities are considered. Firstly, an excessive immune response to bacterial hsp could be arthritogenic — as may occur in reactive arthritis. In these circumstances therapy would be directed to down-regulating this immune response, or altering the nature of the immune response e.g. by changing cytokine production from interferon-g to IL-4. However this approach depends on the immune response to bacterial hsp not being critical for control of the bacterial infection. Secondly, an immune response to bacterial hsp may induce autoimmunity by cross-reactivity, e.g. with the homologous human. This could also be modulated in the same way with a lower likelihood of interfering with control of the infectious agent, since only a component of the immune response against the bacterial hsp will be cross-reactive with self. Thirdly, recent experiments raise the possibility that joint inflammation might be controlled by T cells which recognizes self hsp, particularly hsp60. Therapies might enhance this response; protection from experimental arthritis by prior immunization with hsp60 is well established. Whether similar approaches will be viable after arthritis is established remains to be seen.     

A model for radiofrequency electromagnetic field predictions at outdoor and indoor locations in the context of epidemiological research

We present a geospatial model to predict the radiofrequency electromagnetic field from fixed site transmitters for use in epidemiological exposure assessment. The proposed model extends an existing model toward the prediction of indoor exposure, that is, at the homes of potential study participants. The model is based on accurate operation parameters of all stationary transmitters of mobile communication base stations, and radio broadcast and television transmitters for an extended urban and suburban region in the Basel area (Switzerland). The model was evaluated by calculating Spearman rank correlations and weighted Cohen's kappa (κ) statistics between the model predictions and measurements obtained at street level, in the homes of volunteers, and in front of the windows of these homes. The correlation coefficients of the numerical predictions with street level measurements were 0.64, with indoor measurements 0.66, and with window measurements 0.67. The kappa coefficients were 0.48 (95%‐confidence interval: 0.35–0.61) for street level measurements, 0.44 (95%‐CI: 0.32–0.57) for indoor measurements, and 0.53 (95%‐CI: 0.42–0.65) for window measurements. Although the modeling of shielding effects by walls and roofs requires considerable simplifications of a complex environment, we found a comparable accuracy of the model for indoor and outdoor points. Bioelectromagnetics 31:226–236, 2010. © 2009 Wiley‐Liss, Inc.     

Introduced house mice as a conservation concern on Gough Island

House mice have previously been identified as a significant threat to both species and ecosystems on Southern Ocean islands. To date, these impacts have been quantified on several sub-Antarctic islands, but the role of house mice on more temperate islands is poorly known. On South Atlantic Gough Island, non-commensal house mice (Mus musculus L.) were probably introduced in the early 19th century and are now extremely abundant. To assess the likely impacts of mice on the fauna and flora at Gough Island we examined the diet of this population from September 1999 to July 2000 using conventional snap trapping techniques. The population has a single breeding season from September to March and mean body mass is notable in being amongst the largest reported for non-laboratory M. musculus. At low elevations (<250 m above sea level [a.s.l.]), avian carrion was the most prevalent dietary item during September and October. From November to February, plant material constituted the bulk of stomach contents and from March to July lumbricid worms were the most common food item. Indigenous invertebrate matter contributed little to mouse diet, independent of season. At altitudes greater than 500 m a.s.l., larvae of endemic brachypterous moths made up a significant proportion of stomach contents. In light of studies elsewhere, these data suggest that mouse predation may pose a significant threat to these species. However, it is not clear whether conservation action, such as an eradication attempt, is warranted. Further assessments of the impacts of mice are required, and in the interim every effort should be made to prevent introductions of other potentially harmful invasive species.     

Persistence and vulnerability: Retaining biodiversity in the landscape and in protected areas

An objective of biodiversity conservation activities is to minimize the exposure of biodiversity features to threatening processes and to ensure, as far as possible, that biodiversity persists in the landscape. We discuss how issues of vulnerability and persistence can and should be addressed at all stages of the conservation planning and implementation process. Procedures for estimating the likelihood of persistence and for measuring degrees of vulnerability at different spatial and temporal scales using subjective assessments, rules of thumb and analytical and simulation models are reviewed. The application of information on vulnerability and persistence to conservation planning and management is discussed under the headings of natural dynamics, replication of protection, levels of representation, source and sink population structures, refuges and critical resources, reserve design, habitat fragmentation and levels of management.     

Abundance-range size relationships in British birds: is unexplained variation a product of life history?

Positive interspecific relationships between local abundance and geographic range size are a common feature of animal assemblages However, range size typically explains only a moderate proportion of the variation m abundance, begging the question of whether species of differing life history deviate from the underlying relationship in any systematic fashion Using data for the avifauna of Britain, and applying a comparative method to control for the effects of phylogenetic association, we demonstrate that this does not appear to be the case Only adult survivorship, age at independence and incubation period explain significant variation in abundance once range size is controlled for statistically, and then only a few percent There are two probable reasons why this result is contrary to general expectation First, although many life history variables are expected to show simple correlations with abundance or range size It is not obvious how these might relate to variation about the abundance–range size relationship Second, intuitive ideas about the form such variation might take may be seriously confounded by phylogenetic non–independence