Search results for "complex"
showing 10 items of 5889 documents
Selective feeding of Arctodiaptomus salinus (Copepoda, Calanoida) on co-occurring sibling rotifer species
2004
Summary 1. Using two- and three-dimensional video recordings, we examined the steps involved in predation that lead to the differential vulnerability of three sympatric rotifer sibling species (Brachionus plicatilis, B. ibericus and B. rotundiformis) to a co-occurring, predatory, calanoid copepod (Arctodiaptomus salinus). 2. Brachionus rotundiformis, the smallest prey tested, was the most vulnerable with the highest encounter rate, probability of attack, capture and ingestion, and the lowest handling time. 3. Comparison of our results with those of a previous study shows that A. salinus is a more efficient predator than a co-occurring cyclopoid copepod (Diacyclops bicuspidatus odessanus) fe…
New insights into the taxonomy and phylogeny of social voles inferred from mitochondrial cytochrome b sequences
2012
We sequenced the entire cytochrome b gene in Microtus paradoxus from Turkmenistan and Microtus socialis from Crimea and Kalmykia. Phylogenetic relationships among social voles were reconstructed by the inclusion into analyses of a further 23 published haplotypes belonging to six species. The two probabilistic methods which were used in phylogenetic analyses, the Bayesian inference and Maximum Likelihood, yielded very similar results. Both trees showed two highly divergent lineages which were further subdivided into seven species. The socialis lineage encompassed four species (M. socialis, M. irani, M. anatolicus, and M. paradoxus), and the remaining three species clustered into the guenther…
Verrucoccum (Dothideomycetes, Dictyosporiaceae), a new genus of lichenicolous fungi on Lobaria s. lat. for the Dothidea hymeniicola species complex
2021
Two lichenicolous fungi, one growing on the thallus of Lobaria pulmonaria in the United Kingdom (Scotland) and the other in apothecia of Lobaria linita and L. oregana in northwestern North America (Alaska and British Columbia) and northeast Asia (Russian Far East, Khabarovsk Krai), show similarities to the species originally described as Dothidea hymeniicola (later transferred to Polycoccum s. lat and Endococcus) from a Lobaria s. lat. species in Central America. Critical morphological comparison showed that, despite the superficial resemblance between Alaskan, Canadian, Russian, and Scottish collections and the holotype of Dothidea hymeniicola, they can be distinguished by detailed microsc…
CRYPTIC SPECIES RELATED TO DALDINIA CONCENTRICA AND D. ESCHSCHOLZII, WITH NOTES ON D. BAKERI
2004
Daldinia macaronesica (from the Canary Islands and Madeira), D. palmensis (from the Canary Islands), D. martinii and D. raimundi (from Sicily), and D. vanderguchtiae (from Jersey, Channel Islands) spp. nov., are described, based on new combinations of teleomorphic and anamorphic characters. They all resemble the pantropical D. eschscholzii and/or the European D. concentrica with regard to teleomorphic characters and secondary metabolite profiles generated by analytical HPLC. The status of the newly described taxa was established by SEM of ascospores and microscopic studies of their anamorphs in comparison with various materials of the aforementioned known species. HPLC and SEM studies on th…
Persistent genetic signatures of colonization inBrachionus manjavacasrotifers in the Iberian Peninsula
2007
Recent phylogeographical assessments have consistently shown that continental zooplankton display high levels of population subdivision, despite the high dispersal capacity of their diapausing propagules. As such, there is an apparent paradox between observed cosmopolitanism in the zooplankton that is associated with long-distance dispersal, and strong phylogeographical structures at a regional scale. Such population dynamics, far from migration-drift equilibrium, have been shown in the rotifer species complex Brachionus plicatilis, a group of over a dozen species inhabiting salt lakes and coastal lagoons worldwide. Here we present the mitochondrial DNA phylogeography of one of these specie…
Morphological vs. molecular delineation of taxa across montane regions in Europe: the case study of Gammarus balcanicus Schäferna, (Crustacea: Amphip…
2014
Mountainous areas are characterized by substantial biodiversity and endemicity due to their complex geological history and habitat fragmentation. Hence, it can be assumed that particularly high species richness can be found in organisms with limited dispersal capabilities that inhabit mountain streams. A number of scientific papers focus on molecular phylogeography or traditional taxonomy of species or species groups inhabiting such habitats. However, there is a lack of studies that integrate morphological and molecular data to identify and delineate cryptic species. For practical reasons, uncovering cryptic diversity is crucial in taxa used in biomonitoring. Distinct species, hard to separ…
The parasitoid species complex associated with sexual and parthenogenetic Naryciinae (Lepidoptera: Psychidae): Integrating ecological and molecular a…
2011
This study describes the parasitoid species complex associated with seven closely related species of sexual (Siederia rupi- collella, S. listerella, Dahlica lazuri, D. charlottae and D. lichenella) and parthenogenetic (Dahlica fennicella and D. triquetrella) Naryciinae (Lepidoptera: Psychidae) in Central Finland. A thorough ecological analysis of all the species of parasitoids recorded was combined with analyses of molecular data. Mitochondrial and nuclear DNA data were obtained from all the species in order to (1) detect cryptic species associated with host specialization, (2) assign undescribed males to females, and (3) verify the morphological identification of closely related species. A…
The age and evolution of sociality in Stegodyphus spiders: a molecular phylogenetic perspective
2006
Social, cooperative breeding behaviour is rare in spiders and generally characterized by inbreeding, skewed sex ratios and high rates of colony turnover, processes that when combined may reduce genetic variation and lower individual fitness quickly. On these grounds, social spider species have been suggested to be unstable in evolutionary time, and hence sociality a rare phenomenon in spiders. Based on a partial molecular phylogeny of the genus Stegodyphus , we address the hypothesis that social spiders in this genus are evolutionary transient. We estimate the age of the three social species, test whether they represent an ancestral or derived state and assess diversification relative to s…
Guest-to-host proton transfer in melatonin-beta-cyclodextrin inclusion complex by ionspray, fast atom bombardment and tandem mass spectrometry.
2001
Ionspray (IS) and fast atom bombardment (FAB) positive ionization mass spectrometry (MS) of 1:1 β-cyclodextrin (β-CD)-melatonin (MLT) host-guest complex allowed the detection of gaseous protonated 1:1 β-CD-MLT. Tandem MS collision-induced dissociation (CID) of such protonated 1:1 β-CD-MLT species showed the proton (charge) to be retained to a significant extent by the host and by its cage fragmentation products, in spite of the higher proton affinity of MLT with respect to that of β-CD. This requires an endothermic guest-to-host proton transfer to occur within the gaseous association. Collisional activation could be accounted for by the promotion of such an endothermic process; however…
Guanaconetins, new antitumoral acetogenins, mitochondrial complex I and tumor cell growth inhibitors
2005
The antitumoral activity of a series of acetylated bis-tetrahydrofuranic acetogenins with a threo/trans/threo/trans/erythro relative configuration was characterized by four new natural and two semisynthetic, 15,24,30-trioxygenated acetogenins that were found to inhibit mitochondrial complex I enzyme as well as growth of several tumor cell lines. Placement of acetyl groups along the alkyl chain modulated the potency of the bis-tetrahydrofuranic acetogenins and could be important for future utilization of these compounds as chemotherapeutic agents.