Search results for "Al speciation"
showing 10 items of 45 documents
Divergent Macroparasite Infections in Parapatric Swiss Lake-Stream Pairs of Threespine Stickleback (Gasterosteus aculeatus)
2015
Spatial heterogeneity in diversity and intensity of parasitism is a typical feature of most hostparasite interactions, but understanding of the evolutionary implications of such variation is limited. One possible outcome of infection heterogeneities is parasite-mediated divergent selection between host populations, ecotypes or species which may facilitate the process of ecological speciation. However, very few studies have described infections in populationpairs along the speciation continuum from low to moderate or high degree of genetic differentiation that would address the possibility of parasite-mediated divergent selection in the early stages of the speciation process. Here we provide…
Hybridization in Capparis spinosa L.: Molecular and morphological evidence from a Mediterranean island complex
2014
Inter-Simple Sequence Repeat (ISSR) molecular markers and morphological analysis were used in order to characterize wild populations and cultivated forms of orphan crop species Capparis spinosa L. in a Mediterranean island complex. Nineteen wild populations belonging to two different subspecies, C. spinosa subsp. spinosa and subsp. rupestris, were sampled in different environments in Sicily and the surrounding islets Lampedusa, Pantelleria and Salina. Different biotypes cultivated in Pantelleria and Salina were analyzed. Six ISSR primers were selected for genetic characterization, and all clear and reproducible bands were scored and analyzed. Among the 47 ISSR bands obtained, 97.5% were pol…
2,2′-Oxydiacetato-bridged complexes containing Sm(III) and bivalent cations. Synthesis, structure, magnetic properties and chemical speciation
2006
Abstract Heterometallic compounds containing Sm(III), bivalent cations M (M = Cu, Ni, Co, Mn, Ca, Mg), and 2′,2′-oxydiacetate (oda) as connecting ligand have been prepared and characterized. The complexes can be formulated as [Sm 2 M 3 (oda) 6 ] · xH 2 O. The structure of [Sm 2 Cu 3 (oda) 6 (H 2 O) 6 ] shows the presence of the Sm(III) coordinated by six carboxy and three ether oxygen atoms, and the Cu(II) cation bonded to four carboxy oxygens and two molecules of water. An open 3D framework is observed, containing large hexagonal channels. At room temperature, the polynuclear complexes behave as built by magnetically isolated paramagnetic ions, but at low temperatures, very weak antiferrom…
Sexual and postmating reproductive isolation between allopatric Drosophila montana populations suggest speciation potential
2011
This work was funded by a European Commission Research Training Grant RTN2-2001-00049, the Centre of Excellence for Evolutionary Research at the University of Jyväskylä and a Marie Curie Initial Training Network, ‘Understanding the evolutionary origin of biological diversity’ (ITN-2008-213780 SPECIATION) Background: Widely distributed species with populations adapted to different environmental conditions can provide valuable opportunities for tracing the onset of reproductive incompatibilities and their role in the speciation process. Drosophila montana, a D. virilis group species found in high latitude boreal forests in Nearctic and Palearctic regions around the globe, could be an excellen…
Reproductive isolation among allopatric Drosophila montana populations
2014
An outstanding goal in speciation research is to trace the mode and tempo of the evolution of barriers to gene flow. Such research benefits from studying incipient speciation, in which speciation between populations has not yet occurred, but where multiple potential mechanisms of reproductive isolation (RI: i.e., premating, postmating-prezygotic (PMPZ), and postzygotic barriers) may act. We used such a system to investigate these barriers among allopatric populations of Drosophila montana. In all heteropopulation crosses we found premating (sexual) isolation, which was either symmetric or asymmetric depending on the population pair compared. Postmating isolation was particularly strong in c…
How did terricolous fungi originate in the Mediterranean region? A case study with a gypsicolous lichenized species
2019
Aim: The historical causes responsible for the wide distribution of terricolous, crustose lichenized fungi across the Mediterranean Basin and the Canary Islands have never been explored. Here, we used the terricolous, circum-Mediterranean/Macaronesian species Buellia zoharyi (Caliciaceae, Ascomycota) to infer the time frame, and the climatic, geological and ecological factors influencing the origin and current spatial distribution of this species. Location: Mediterranean Basin and Canary Islands. Methods: Data from two nuclear markers (nrITS and tef1) obtained from 226 specimens of 23 populations covering the entire distribution range of B. zoharyi were used to calculate genetic diversity i…
Distribution of Lanthanides in Mediterranean Coastal waters
2007
Distribution and behaviour of the whole lanthanide series and yttrium in both seawater column and suspended particulate matter were investigated in coastal water located in the Central Mediterranean Sea. An area characterized by high anthropic pressure, atmospheric fallout and river input due to drainage of little local watersheds was selected. Water masses were discriminated with respect to both surrounding and depth and in relation to the processes occurring at the solid-liquid interface. We found that yttrium and Rare Earth Elements in the labile fraction of the suspended particulates result from the mixing between lithogenic material from the Sicilian basin and detrital material of Saha…
The solution behavior of dopamine in the presence of mono and divalent cations: A thermodynamic investigation in different experimental conditions
2021
The interactions of dopamine [2-(3,4-Dihydroxyphenyl)ethylamine, (Dop-)] with methylmercury(II) (CH3Hg+), magnesium(II), calcium(II), and tin(II) were studied in NaCl(aq) at different ionic strengths and temperatures. Different speciation models were obtained, mainly characterized by mononuclear species. Only for Sn2+ we observed the formation of binuclear complexes (M2L2 and M2LOH (charge omitted for simplicity)
Diversification and community assembly of the world’s largest tropical island
2022
Aim: The species diversity and endemism of tropical biotas are major contributors to global biodiversity, but the factors underlying the formation of these systems remain poorly understood. Location: The world's largest tropical island, New Guinea. Time period: Miocene to present. Major taxa studied: Passerine birds. Methods: We first generated a species-level phylogeny of all native breeding passerine birds to analyse spatial and elevational patterns of species richness, species age and phylogenetic diversity. Second, we used an existing dataset on bill morphology to analyse spatial and elevational patterns of functional diversity. Results: The youngest New Guinean species are principally …
Bioavailability and assessment of heavy metal pollution in sediment cores off the Mejerda River Delta (Gulf of Tunis): How useful is a multiproxy app…
2016
International audience; Three core samples were taken from zones offshore from the Mejerda River Delta (Tunisia) and analyzed formajor and trace elements to assess their relationships with organic matter, monosulfides and carbonates, aswell as for pollution and bioavailability. Chemical speciation,ΣSEM/AVS, the enrichment factor (EF) and thegeo-accumulation index (I-geo) were used. Iron, cadmium, lead and zinc – the most frequently mined metalsin the Mejerda catchment – were found as contaminants in the offshore areas. Estimations of trace elementaccumulation using the EF and the I-geo index show that lead, and to a lesser extent zinc, are the most pollutingmetals off the Mejerda outlet. Ac…