A review of the subspecies status of the Icelandic Purple Sandpiper Calidris maritima littoralis

The Icelandic Purple Sandpiper Calidris maritima littoralis (C.L. Brehm, 1831) represents one member of a poorly understood subspecies complex. Currently, differences in size define two other subspecies: Calidris maritima belcheri Engelmoer & Roselaar, 1998, which breeds in north‐eastern Canada along the Hudson Bay and James Bay, and Calidris maritima maritima (Brunnich, 1764), which breeds along the Arctic coasts elsewhere in northern Canada, Greenland, Svalbard, Scotland, and Fennoscandia, to northern central Siberia. There are large size differences amongst populations of C. m. maritima, however. As an Arctic/Alpine breeding bird, C. m. littoralis could provide an interesting perspective on the evolutionary changes following a northwards expansion of a species after glacial retreat. Considering the extent of the ice sheet in the northern hemisphere during the last glaciation, and the short period of time since it ended, the correct attribution of subspecies status for C. m. maritima may reflect either rapid diversification from a single population or ancestral splits of distinct evolutionary lineages that survived in isolation at southern latitudes. We applied morphometric subspecies criteria, diagnosability by Amadon's rule, and genetic analysis of five nuclear introns, and the mitochondrial DNA markers cytochrome oxidase c subunit I (COI) and NADH dehydrogenase subunit 2 (ND2), to geographically separate breeding populations in order to examine the subspecies status of the Icelandic population. The results do not provide support for the subspecies status of the Icelandic population because the nominate and Icelandic subspecies fail to uphold Amadon's rule, and genetic analyses indicate that the study populations derive from a single shared refugium. © 2015 The Linnean Society of London     

Characterization of aggregates produced by the potential mycoherbistat Plectosporium alismatis in submerged culture: germination,UV-radiation tolerance and infectivity

Plectosporium alismatis, a potential mycoherbistat of Alismatacae spp., has been previously shown to produce aggregates which contain chlamydospores in liquid culture. Weevaluated the impact of medium composition on the formation and composition of aggregates. In shake flasks cultures using 5.74 gL^?1 sodium nitrate, 8.8 gL^?1 malt extract or glucose and 0.1% Tween 80, P. alismatis formed small, uniform (diameter of 75% aggregates <720 µm), dense, melanised aggregates containing 10⁴ conidia and 10³ chlamydospores, these numbers remained unchanged during growth. All 7-day-old aggregates exposed to desiccation or/ and UV-radiation germinated. In bioassays using leaf discs of Alisma plantago-aquatica, P. alismatis aggregates caused necrosis, regardless of whether aggregates had been exposed to desiccation and/or UV-radiation prior to application on leaf discs, whereas other propagules (10³ propagules disc^?1) exposed to drying and UV-radiation stress were unable to cause necrosis. This preliminary research shows the potential of aggregates to be used as part of a formulation of biocontrol agents, provided adequate conditions for optimal aggregate yields are found.     

Comparative study of biological hydrogen production by pure strains and consortia of facultative and strict anaerobic bacteria

In this paper, a simple and rapid method was developed in order to assess in comparative tests the production of binary biogas mixtures containing CO₂ and another gaseous compound such as hydrogen or methane. This method was validated and experimented for the characterisation of the biochemical hydrogen potential of different pure strains and mixed cultures of hydrogen-producing bacteria (HPB) growing on glucose.The experimental results compared the hydrogen production yield of 19 different pure strains and sludges: facultative and strict anaerobic HPB strains along with anaerobic digester sludges thermally pre-treated or not. Significant yields variations were recorded even between different strains of the same species by i.e. about 20% for three Clostridium butyricum strains. The pure Clostridium butyricum and pasteurianum strains achieved the highest yields i.e. up to 1.36 mol H₂/mol glucose compared to the yields achieved by the sludges and the tested Escherichia and Citrobacter strains.     

Substrate profiling of IGF-1R and InsR: identification of a potent pentamer substrate

Protein kinases are widely recognized as important therapeutic targets due to their involvement in signal transduction pathways. These pathways are tightly controlled and regulated, notably by the ability of kinases to selectively phosphorylate a defined set of substrates. As part of a study on the substrate requirements of Insulin-like Growth Factor 1 Receptor (IGF-1R) and Insulin Receptor (InsR), we evaluated and applied a universal assay system able to monitor the phosphorylation of unlabelled peptides of any length in real time. In contrast to already reported profiling methodologies, we were able to assess the k(cat)/K(M) ratio of peptides as short as tetramers. Notably, we were able to identify an efficient pentamer substrate that exhibited kinetic properties close to those of a 250-amino acid protein derived from IRS-1, a natural substrate of IGF-1R and InsR.     

Effects of light deprivation on visual evoked potentials in migraine without aura

Background  

The mechanisms underlying the interictal habituation deficit of cortical visual evoked potentials (VEP) in migraine are not well understood. Abnormal long-term functional plasticity of the visual cortex may play a role and it can be assessed experimentally by light deprivation (LD).     

Generation of transgenic mice overexpressing EfnB2 in endothelial cells

Genetic studies have shown that ephrin-B2 and its cognate EphB4 receptor are necessary for normal embryonic angiogenesis. Moreover, there is overwhelming evidence that ephrin-B2 is involved in tumor vascularization, yet its role in adult angiogenesis has been difficult to track genetically. Here, we report the generation of transgenic mice that over-express EfnB2 specifically in endothelial cells (ECs). We show that exogenous expression of EfnB2 under the control of the Tie2 promoter/enhancer regions in ECs does not affect viability or growth of the transgenic animals. We further show that targeted expression of EfnB2 in ECs is not sufficient to rescue severe cardiovascular defects at mid-gestation stages but rescues early embryonic lethality associated with loss-of-function mutation in EfnB2. This mouse model will be useful to study the role of ephrin-B2 in physiological and pathological angiogenesis.