634 research outputs found
Evolution of miniaturization and the phylogenetic position of Paedocypris, comprising the world's smallest vertebrate
10.1186/1471-2148-7-38BMC Evolutionary Biology7
Design, Construction and Metrology of the Overlap Detectors for the ALFA system
The Overlap Detectors of the ALFA syste
Mitochondrial Genetic Differentiation of Spirlin (Actinopterigii: Cyprinidae) in the South Caspian Sea basin of Iran
Background Knowledge about Alburnoides remains lacking relative to many other species, resulting in a lack of a systematic position and taxonomic diagnosis. Basic biological information for Alburnoides has been constructed, and it is necessary to understand further and obtain more information about this species. Its phylogenetic relationships are still debated and no molecular data have been used to study this taxon in Iran. A holistic approach for genetic methods was adopted to analyze possible spirlin population differences at selected centers in the south Caspian Sea basin of Iran. Methods The phylogenetic relationships were determined based on 774 base pairs of the mitochondrial cytochrome b gene of 32 specimens of spirlin from nine locations in the south Caspian Sea drainage basin of Iran. The nucleotide sequences were subjected to phylogenetic analysis using the neighbor-joining, maximum parsimony, maximum likelihood, and Bayesian methods. Results The mitochondrial gene tree largely supports the existence of three major clades. The western populations (clade I) may be considered as Alburnoides eichwaldii , whereas the Talar river populations (clade II) are represented as Alburnoides sp. 1 and the eastern populations (clade III) may be distinct taxa of Alburnoides sp.2. Conclusion This molecular evidence supports the hypothesis that A. bipunctatus does not exist in the south Caspian Sea basin of Iran, and that the western and eastern populations are distinct taxa
A revision of the akysid catfish genus Acrochordonichthys Bleeker
Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/75446/1/j.1095-8649.2001.tb02260.x.pd
Towards cardiolite-inspired carbon monoxide releasing molecules – Reactivity of d4, d5 rhenium and d6 manganese carbonyl complexes with isocyanide ligands
Carbon monoxide releasing molecules (CORMs) are investigated widely in synthetic and medicinal chemistry owing to the potential therapeutic applications of the CO gas. Organometallic carbonyl complexes are best suited to play the role of CO carriers as they allow the exogenous release of CO under controlled conditions, and the toxicity of the gas can be overcome. With the long-term goal of developing CORMs with similar properties to those of the sesta-methoxyisobutylisonitrile (sesta-mibi) 99mTc complex (Cardiolite), we have studied the reactivity of isocyanide ligands towards 16- and 17-electron cis-[Re(CO)₂Br₄]–/2– species and the [Mn(CO)₅Br] complex. Six different isocyanide ancillary ligands (CNR), including mibi, were selected for this study. Their reactions with cis-dicarbonyl ReIII and ReII complexes were accompanied by two- and one-electron reduction of the metal center and resulted in the formation of stable cis-mer-[Re(CO)₂(CNR)₃Br] species, whereas the same reactions with [Mn(CO)₅Br] gave fac-[Mn(CO)₃(CNR)₂Br] compounds. All of the complexes were fully characterized, and single-crystal X-ray diffraction structure determinations were performed for selected species. In addition, unique monocarbonyl complexes were obtained from the reactions of cis-[Re(CO)₂Br₄]⁻ (1) with tert-butyl isocyanide and cis-[Re(CO)₂Br₄]²⁻ (2) with mibi. The species, a heptacoordinate ReIII and a hexacoordinate ReII complex, respectively, were also characterized structurally. The CO-releasing profiles, the cytotoxic effects against 3T3 fibroblast cells, and the antibacterial properties of the compounds were also investigated
Managing cryptic biodiversity: fine-scale intralacustrine speciation along a benthic gradient in Alpine whitefish ( Coregonus spp.)
Whitefish (Coregonus spp.) are an important catch for many freshwater fisheries, particularly in Switzerland. In support of this, supplemental stocking of whitefish species is carried out, despite lacking complete knowledge of the extent, distribution and origin of whitefish diversity in these lakes, potentially threatening local endemics via artificial gene flow. Here, we investigate phenotypic and genetic differentiation among coexisting whitefish species spawning along a depth gradient in a subalpine Swiss lake to better delineate intralacustrine whitefish biodiversity. We find depth-related clines in adaptive morphology and in neutral genetic markers. This individual variation is structured in three distinct clusters with spatial overlap. Individual genetic distances correlate strongly with differences in growth rate and gill-raker number, consistent with predictions of isolation-by-adaptation and ecological speciation. Genetic differentiation between species suggests reproductive isolation, despite demographic admixture on spawning grounds. Our results are consistent with clinal speciation resulting in three species coexisting in close ecological parapatry, one (C. sp. “benthic intermediate”) being previously unknown. A second unknown species spawning in close proximity, was found to be of potential allochthonous origin. This study highlights the importance of taxonomically unbiased sampling strategies to both understand evolutionary mechanisms structuring biodiversity and to better inform conservation and fisheries management
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