Quadruplexes In ‘Dicty’: Crystal Structure Of A Four-Quartet G-Quadruplex Formed By G-Rich Motif Found In The Dictyostelium Discoideum Genome

Guanine-rich DNA has the potential to fold into non-canonical G-quadruplex (G4) structures. Analysis of the genome of the social amoeba Dictyostelium discoideum indicates a low number of sequences with G4-forming potential (249–1055). Therefore, D. discoideum is a perfect model organism to investigate the relationship between the presence of G4s and their biological functions. As a first step in this investigation, we crystallized the dGGGGGAGGGGTACAGGGGTACAGGGG sequence from the putative promoter region of two divergent genes in D. discoideum. According to the crystal structure, this sequence folds into a four-quartet intramolecular antiparallel G4 with two lateral and one diagonal loops. The G-quadruplex core is further stabilized by a G-C Watson–Crick base pair and a A–T–A triad and displays high thermal stability (Tm \u3e 90°C at 100 mM KCl). Biophysical characterization of the native sequence and loop mutants suggests that the DNA adopts the same structure in solution and in crystalline form, and that loop interactions are important for the G4 stability but not for its folding. Four-tetrad G4 structures are sparse. Thus, our work advances understanding of the structural diversity of G-quadruplexes and yields coordinates for in silico drug screening programs and G4 predictive tools

Comprehensive economic and spatial bio-energy modelling . Chania : CIHEAM / INRA

To cite th is article / Pou r citer cet article -------------------------------------------------------------------------------------------------------------------------------------------------------------------------- Abstract: Life Cycle Activity Analysis (LCAA) -a mathematical programming decision support model for the optimization of the entire life cycle of products -is presented. LCAA is a new tool for the mapping of hierarchical production and recovery chains, their impact on the environment, and for a holistic evaluation of new technologies, environmental strategies or policies. LCAA involves three successive stages of analysis: i) a description of all participating activities (processing, transport, use, recovery, …) as a good travels from its "cradle" to its "grave", including the inventory of ancillary materials and energy supplied to each activity, economic costs and environmental burdens; ii) the formulation and numerical solution of a linear or nonlinear mathematical programming model and iii) the evaluation of a set of environmental scenarios of interest to policy-decision-makers or stakeholders. It is shown how LCAA contributes to the conceptualization of Industrial Ecology, which can be seen as a new paradigm for the integration of environmental and economic performance. The antecedents of LCAA (classical Activity Analysis adjoined to the environmental Life Cycle Assessment framework) are surveyed. Illustrative conceptual mathematical programming formats are discussed and the potential of LCAA, the type of problems to be addressed and its relevance to environmental policy are further explored

Årbok 1964

To date, only one study by Strick and Volbeda (2018), titled ‘When the valence of unconditioned stimuli evolves over time: Evaluative conditioning with good-ending and bad-ending stories’, investigated stories in the context of evaluative conditioning to change brand attitudes. To find additional support for stories as unconditioned stimuli, we performed a partial replication of this study. As an extension, we also investigated the role of the need for affect as a mediator in this conditioning process. Our study had a within-subject design, in which MTurk workers (N = 66) participated in both our good- and bad-ending story conditions. In line with the original study and our hypothesis, our results suggest that the valence of the story ending determines the direction of the conditioning effect. Brands presented after good-ending stories have a stronger brand liking than brands presented after bad-ending stories. In practice, this would imply that advertisements should always end positively to induce a positive brand evaluation. Furthermore, as we hypothesized, our results indicate that the need for affect mediates this conditioning effect as people with a high need for affect rate brands more emotionally and strongly according to the story-ending valence than people with a low need for affect. Future research may distinguish other characteristics that mediate this effect to identify separate groups for targeted advertisements. To conclude, the ending of dramatic stories is determinative in brand evaluation when the brand is presented directly after, and the effect of these story endings is mediated by the need for affect