Introduction of jumping fragments in combination with QSARs for the assessment of classification in ecotoxicology.

Starting from a random set of structures taken from the European Chemical Bureau (ECB) Web site, an estimation of the classification by acute category in ecotoxicology was carried out. This estimation was based on two approaches. One approach consists in starting with global quantitative structure-activity relationship (QSAR) equations, analyzing the results and defining an interpretation in terms of overall results and mode of action. The other starts with the notion of emerging fragments and more specifically with the introduction of a particular concept: the jumping fragments. This publication studies the scopes and limitations of each approach for the classification of the derivatives. A promising combination of the two methods is proposed for the classification and also for bringing new information about the importance, for the ecotoxicity, of specific chemical fragments considered alone or in association with others.

Both calcitonin and calcitonin gene-related peptides' thresholds of hypophagia are considerably lower in chicks selected for high rather than low juvenile body weight.

Effects of intracerebroventricular (ICV) injection of calcitonin (CT) and calcitonin gene-related peptide (CGRP) on food and water intake were measured in two lines of White Plymouth Rock chickens from a common base population that have undergone long-term divergent selection for either low (LWS) or high (HWS) juvenile body weight. These lines contain anorexic and obese individuals and serve as models for hypo- and hyperphagia. For both ICV injection of CT and CGRP, line HWS responded to a lower dose with decreased food intake than did line LWS. Both peptides were also associated with reduced water intake in both lines. Although plasma glucose concentrations were inherently different between lines, neither CT nor CGRP affected these levels. Comprehensive behavior analyses were conducted and only the number of food pecks was differentially suppressed between lines after both CT and CGRP injection. Thus, the selection program may have caused alterations in the endogenous CT and CGRP systems that synergistically, with other neurotransmitter systems, contribute to the role of food intake on the differential body weights between these lines.