Anti-infective properties of bacteriocins: an update

Bacteriocin production is a widespread phenomenon among bacteria. Bacteriocins hold great promise for the treatment of diseases caused by pathogenic bacteria and could be used in the future as alternatives to existing antibiotics. The anti-infective potential of bacteriocins for inhibiting pathogens has been shown in various food matrices including cheese, meat, and vegetables. However, their inhibition of pathogens in vivo remains unclear and needs more investigation, due mainly to difficulties associated with demonstrating their health benefits. Many bacteriocins produced by established or potential probiotic organisms have been evaluated as potential therapeutic agents and interesting findings have been documented in vitro as well as in a few in vivo studies. Some recent in vivo studies point to the efficacy of bacteriocin-based treatments of human and animal infections. While further investigation remains necessary before the possibilities for bacteriocins in clinical practice can be described more fully, this review provides an overview of their potential applications to human and veterinary health.     

Role of glucocorticoids on the maturation of brush border enzymes in fetal rat gut endoderm

Summary Heterospecific recombinants between fetal rat intestinal endoderm and chick mesenchyme, and also undissociated fetal rat intestine, were submitted to different hormonal environments. The present study shows that exogenouslysupplied dexamethasone in organ culture, like endogenous hormones provided by the adult rat (grafting experiments) led to similar qualitative and quantitative results, i.e., a 9-fold stimulation of maltase and a precocious induction of sucrase activity in comparison with anhormonal conditions.Supported by grant CRL 80 70 17 from the INSERM and by the CNRS. This work was presented in part at the XVth EDBO International Embryological Conference.     

Effet inhibiteur de la tétrabénazine sur l'influence corticosurrénalienne de la réserpine

Summary Reserpine provokes an intense and long-lasting (more than 20 h) stimulation of the adrenocortical activity of the rat. Tetrabenazin (50 mg/kg) also produces an adrenocortical stimulation which is, however, of a much shorter duration. The injection of tetrabenazin 1 h before the injection of reserpine (5 mg/kg) prevents the prolonged stimulating effect of reserpine on the adrenal cortex. This effect can be compared with the blocking effect of tetrabenazin, a short-acting central depressant with monoamine-liberator properties, against the prolonged central sedative influence of reserpine.     

Recalcificationin vitro de l'os compact décalcifié

Summary We report the possibility of recalcifying decalcified sections of adult compact bone. Recalcification occurs mainly in those osteons which had a low calcium contentin vivo.     

Functional diversity governs ecosystem response to nutrient enrichment

The relationship between species diversity and ecosystem functioning is a central topic in ecology today. Classical approaches to studying ecosystem responses to nutrient enrichment have considered linear food chains. To what extent ecosystem structure, that is, the network of species interactions, affects such responses is currently unknown. This severely limits our ability to predict which species or functional groups will benefit or suffer from nutrient enrichment and to understand the underlying mechanisms. Here our approach takes ecosystem complexity into account by considering functional diversity at each trophic level. We conducted a mesocosm experiment to test the effects of nutrient enrichment in a lake ecosystem. We developed a model of intermediate complexity, which separates trophic levels into functional groups according to size and diet. This model successfully predicted the experimental results, whereas linear food-chain models did not. Our model shows the importance of functional diversity and indirect interactions in the response of ecosystems to perturbations, and indicates that new approaches are needed for the management of freshwater ecosystems subject to eutrophication.