ALBERT

Description: Aims This study explores the patterns of niche differentiation in a group of seven closely related columbines (genus Aquilegia , Ranunculaceae) from the Iberian Peninsula. Populations of these columbines are subject to complex patterns of divergent selection across environments, which partly explain the taxonomic structure of the group. This suggests the hypothesis that niche divergence must have occurred along the process of diversification of the group. Methods We used MaxEnt to build environmental niche models of seven subspecies belonging to the three species of Aquilegia present in the Iberian Peninsula. From these models, we compared the environmental niches through two different approaches: ENMtools and multivariate methods. Important Findings MaxEnt distributions conformed closely to the actual distribution of the study taxa. ENMtools methods failed to uncover any clear patterns of niche differentiation or conservatism in Iberian columbines. Multivariate analyses indicate the existence of differentiation along altitudinal gradients and along a gradient of climatic conditions determined by the summer precipitation and temperatures. However, climatic conditions related to winter temperature and precipitation, as well as soil properties, were equally likely to show conservatism or divergence. The complex patterns of niche evolution we found suggest that Iberian Columbines have not been significantly constrained by forces of niche conservatism, so they could respond adaptively to the fast and profound climate changes in the Iberian Peninsula through the glacial cycles of the Pleistocene.

Description: Aims Phenotypic plasticity and local adaptation of populations at their distributional limits are crucial to understand species colonization and persistence in novel or marginal environments, as well as species divergence and niche width evolution. We assess the contribution of these processes to shape current elevational limits and determine elevational phenotypic divergence between two subspecies of Aquilegia vulgaris (subsp. vulgaris and nevadensis ). Methods We conducted sowing and transplant experiments considering four elevations throughout the current elevational range of A. vulgaris in southern Iberian Peninsula. Experiments were designed to explore, on the one hand, local adaptation through three components of performance (germination, survival and growth) and, on the other hand, the phenotypic differentiation and/or plasticity associated to local adaptation. Four populations per subspecies (three from the elevational core and one from the elevational boundary) were used as seed sources. Patterns of local adaptation and phenotypic differentiation are examined in the context of the ‘centre-periphery’ hypothesis. Important Findings Central populations of both subspecies performed better at their local elevations while marginal populations were maladapted, confirming the hypothesis and contributing to explain the current elevational segregation of these subspecies. Density of glandular pubescence and germination timing seem to be related to local adaptation, through phenotypic differentiation between subspecies or elevations. The widespread subsp. vulgaris showed signals of adaptive plasticity in the timing of germination while it was not the case in the endemic subsp. nevadensis .

Description: Aims Experimental studies of the response to environmental variation of closely related taxa are needed to understand the mechanisms underlying phenotypic divergence, habitat segregation and range span within a radiating genus. We explored the magnitude of phenotypic differentiation and adaptive plasticity in relation to edaphic variation and its significance for habitat segregation and range span in Iberian columbines. Methods We performed a common garden experiment varying soil type (calcareous vs. siliceous) and depth (rocky-shallow vs. deep) with two pairs of widespread and narrowly distributed subspecies of Iberian columbines: Aquilegia vulgaris (subspp. vulgaris and nevadensis ) and Aquilegia pyrenaica (subspp. pyrenaica and cazorlensis ). We compared tolerance to edaphic variation, trait differentiation and adaptive plasticity of 10 morpho-functional traits between species and distribution ranges. Additionally, we obtained estimates of the competitive environment faced by each taxon in two to four populations per taxa. Important Findings Results partially support hypotheses of higher competitive ability and tolerance to edaphic variation in widespread than in narrow endemic taxa. At the species level, the widely distributed taxon was the most tolerant to edaphic variation. Within species, no consistent pattern emerged since the population from the most widespread subspecies was the most tolerant in A. vulgaris but not in A. pyrenaica . Columbines were differentiated in many traits at species and range level. However, the pattern of differentiation does not fully support the hypothesis of higher specialization and stress tolerance in narrow endemics. Although plasticity was generally low, the results support the hypothesis of adaptive plasticity in widespread but not in restricted taxa at least at species level. Ecological differences (adaptive plasticity and competitive ability among others) may have contributed to phenotypic divergence and edaphic niche segregation, as well as to differences in range span among columbines.

Description: The development of synthetic biological systems requires modular biomolecular components to flexibly alter response pathways. In previous studies, we have established a module-swapping design principle to engineer allosteric response and DNA recognition properties among regulators in the LacI family, in which the engineered regulators served as effective components for implementing new cellular behavior. Here we introduced this protein engineering strategy to two regulators in the TetR family: TetR (UniProt Accession ID: P04483) and MphR (Q9EVJ6). The TetR DNA-binding module and the MphR ligand-binding module were used to create the TetR-MphR. This resulting hybrid regulator possesses DNA-binding properties of TetR and ligand response properties of MphR, which is able to control gene expression in response to a molecular signal in cells. Furthermore, we studied molecular interactions between the TetR DNA-binding module and MphR ligand-binding module by using mutant analysis. Together, we demonstrated that TetR family regulators contain discrete and functional modules that can be used to build biological components with novel properties. This work highlights the utility of rational design as a means of creating modular parts for cell engineering and introduces new possibilities in rewiring cellular response pathways.

Description: Im Kontext der funktionalen Entmischung wurde das Wachstum des Pendlerverkehrs am Beispiel der Region Nordwestschweiz thematisiert. Es bestätigte sich, dass die interkommunale Pendlermobilität stark zugenommen hat. Der Anteil der interkommunalen Pendler stieg zwischen 1970 und 1990 von 33% auf 52%. Trotz der Bevölkerungssuburbanisierung dominiert der interkommunale Pendlerverkehr innerhalb und in die Agglomeration Basel, da sich das Arbeitsplatzangebot weiterhin in der Agglomeration Basel konzentriert. Im interkommunalen Pendlerverkehr ist in den 80er Jahren der öffentliche Verkehr stärker gewachsen als der motorisierte Indidividualverkehr. Dies im Unterschied zum starken Wachstum des MIV in den 70er Jahren. In der Stadt Basel benutzten 1990 57% aller intrakommunalen Pendler ein öffentliches Verkehrsmittel. Dieser Anteil betrug 1990 in den ländlich-peripheren Gemeinden durchschnittlich 3%. Um dem Trend der zunehmenden Trennung zwischen Wohnen und Arbeiten entgegenzuwirken, sind einerseits Massnahmen zur Steigerung der Wohnstandortqualität in den Zentrumsgemeinden zu ergreifen. Andererseits kann längerfristig die Zunahme des Pendlerverkehrs im allgemeinen und des motorisierten Individualverkehrs im speziellen nur durch Kostenwahrheit im Verkehr (Road-Pricing usw.) und durch restriktive Massnahmen in den vom Verkehr betroffenen Gemeinden verhindert werden.