Finish with a sprint: Evidence for time‐selected last leg of migration in a long‐distance migratory songbird

Under time‐selected migration, birds should choose a strategy for outcompeting rivals over securing access to prime resources at the final destination. Thus, migration can be viewed as a race among individuals where winners are arriving first when conditions are suitable. The sprint migration hypothesis predicts that individuals shift from maximum sustained speed to a final burst of sprint to shorten the transition from migration to breeding (Alerstam, 2006). In this study, we test the hypothesis of a final sprint migration in a long‐distance Afro‐Palearctic migrant, the collared flycatcher Ficedula albicollis, during autumn and spring, and compare migration strategies between the seasons. In both seasons, collared flycatchers evidently exhibited sprint migration by increasing their overall speed over the last leg of migration after the Sahara crossing. This phenomenon was more pronounced in spring, contributing to overall faster spring migration and possibly highlighting higher importance for early arrival at the breeding grounds. In both seasons and particularly in spring, late departing individuals flew at a faster rate, partially being able to catch up with their early departing conspecifics. Differential fueling strategies may play an important role in determining migration speed, especially during the early stages of the migration, and might explain the observed differences in migration speeds between late and early departing individuals. Our findings suggest competition for early arrival at the breeding and at the nonbreeding destinations alike. Sprint migration might be an appropriate strategy to gain advantage over conspecifics and settle in prime territories as well as to cope with the increasingly earlier springs at high latitudes.     

Optimized syntheses of Fmoc azido amino acids for the preparation of azidopeptides

The rise of CuI‐catalyzed click chemistry has initiated an increased demand for azido and alkyne derivatives of amino acid as precursors for the synthesis of clicked peptides. However, the use of azido and alkyne amino acids in peptide chemistry is complicated by their high cost. For this reason, we investigated the possibility of the in‐house preparation of a set of five Fmoc azido amino acids: β‐azido l ‐alanine and d ‐alanine, γ‐azido l ‐homoalanine, δ‐azido l ‐ornithine and ω‐azido l ‐lysine. We investigated several reaction pathways described in the literature, suggested several improvements and proposed several alternative routes for the synthesis of these compounds in high purity. Here, we demonstrate that multigram quantities of these Fmoc azido amino acids can be prepared within a week or two and at user‐friendly costs. We also incorporated these azido amino acids into several model tripeptides, and we observed the formation of a new elimination product of the azido moiety upon conditions of prolonged couplings with 2‐(1H‐benzotriazol‐1‐yl)‐1,1,3,3‐tetramethyluronium hexafluorophosphate/DIPEA. We hope that our detailed synthetic protocols will inspire some peptide chemists to prepare these Fmoc azido acids in their laboratories and will assist them in avoiding the too extensive costs of azidopeptide syntheses. Experimental procedures and/or analytical data for compounds 3 – 5 , 20 , 25 , 26 , 30 and 43 – 47 are provided in the supporting information. © 2017 The Authors Journal of Peptide Science published by European Peptide Society and John Wiley & Sons Ltd.     

Occurrence and transferability of β-lactam resistance inEnterobacteriaceae isolated inChildren's University Hospital in Bratislava

Occurrence and transferability of β-lactam resistance in 30 multi-resistantEscherichia coli, Klebsiella spp.,Enterobacter spp.,Pantoea agglomerans, Citrobacter freundii andSerratia marcescens strains isolated from children between 0 and 3 years of age is presented. The strains were resistant to ampicillin (30), cefoxitin (22), cefotaxime (30), ceftriaxone (30), ceftazidime (30) and aztreonam (28), but susceptible to cefepime (30) and imipenem (26). Twenty-eight of 30 isolates possessed a transferable resistance confirmed by conjugation and isolation of 79–89-kb plasmids. The β-lactam resistance was due to production of β-lactamases and ceftazidime proved to be stronger β-lactamase inductor than ceftriaxone. Twenty-five clinical isolates expressed transferable extended spectrum β-lactamases, and chromosomally encoded AmpC β-lactamase.     

Thrombin inhibitors with lipid peroxidation and lipoxygenase inhibitory activities

Vascular oxidative stress, endothelial injury, and thrombosis are intertwined processes that display a synergistic pathological effect in many cardiovascular diseases. Antithrombotic therapy with anticoagulant and/or antiplatelet agents, combined with interventions against vascular oxidative stress and/or inflammation, both boosting endothelial antithrombotic potential, could display a synergistic action in the treatment of thrombosis. Of the compounds 10a-h and 11a-d, shown to possess thrombin inhibitory activity, 11a-d were found to display radical scavenging activity, 10a, 10d, and 10f were demonstrated to inhibit lipid peroxidation of linoleic acid, and 10b and 10h inhibited soybean lipoxygenase. The observed combination of thrombin inhibition with lipid peroxidation and/or lipoxygenase inhibitory activity makes compounds 10 and 11 interesting candidates for further investigations towards multiple antithrombotic drugs.     

Can a benthic diatom community complement chemical analyses and discriminate between disturbed and undisturbed saline wetland habitats? A study of seven soda pans in Serbia

Soda pans are protected in the European Union as Natura 2000 areas in the category of “Pannonic saline steppes and marshes”. There are at least six soda pans of reference status in Serbia and only a half have strict legal protection. The number of similar, but disturbed (modified) habitats that could be reconstructed is still unknown. We conducted sampling in five natural and two disturbed soda pans aiming to compare a difference in physical and chemical water properties and benthic diatom communities. In addition, we tried to apply recently developed Diatom Index for Soda Pans (DISP) and Trait-based index (TBI) to test the applicability of taxonomic and trait-based approaches in ecological status assessment of soda pans in the southern part of the Carpathian Basin. In contrast to natural soda pans, lower pH and nutrients levels were recorded in disturbed pans. A total of 86 taxa of benthic diatoms, including 11 new for diatom flora of Serbia, were identified. A lower species richness and Shannon index was recorded in natural soda pans. Nitzschia austriaca, N. supralitorea, Navicula veneta and N. wiesneri were dominant diatoms in soda pans of the reference status. Both diatom indices were in average lower in disturbed pans, and this difference was statistically significant for DISP index. We concluded that two indices, supplemented with indicator values for some local diatom species, can be a promising tool for soda pan conservation in this part of the Carpathian Basin.

     

Structural diversity of nucleoside phosphonic acids as a key factor in the discovery of potent inhibitors of rat T-cell lymphoma thymidine phosphorylase

Structurally diverse, sugar-modified, thymine-containing nucleoside phosphonic acids were evaluated for their ability to inhibit thymidine phosphorylase (TP, EC 2.4.2.4) purified from spontaneous T-cell lymphomas of an inbred Sprague-Dawley rat strain. From a large set of tested compounds, among them a number of pyrrolidine-based derivatives, 10 nucleotide analogues with IC₅₀ values below 1 μM were selected. Out of them, four compounds strongly inhibited the enzyme with IC₅₀ values lying in a range of 11–45 nM. These most potent compounds might be bi-substrate analogues.     

Occurrence and chemical diversity of the genus Bryoria in the Sučí Potok Valley, Veporské Vrchy Mountains (Central Slovakia)

Four species of the genus, Bryoria were found in the Sučí Potok Valley: B. capilaris (Ach.) Brodo & D. Hawksw., B. fuscescens (Gyeln.) Brodo & D. Hawksw., B. implexa (Hoffm.) Brodo & D. Hawksw., B. nadvornikiana (Gyeln.) Brodo & D. Hawksw. The most common species in the valley was B. implexa. Four chemotypes of this lichen were recognized.     

Phytochemical Study of Juglans regia L. Pericarps from Greece with a Chemotaxonomic Approach

Phytochemical research of different polarity extracts from green Juglans regia L. pericarps from Greece afforded 32 compounds: four pentacyclic triterpenes (1 – 4), three sesquiterpenes (5 – 7), four tetralones (8 – 11), two naphthoquinones (12 and 13), seven phenolic acids (14 – 20), one diarylheptanoid (21), one neo‐lignan (22), seven flavonoids (23 – 29), two phenylethanoids (30 and 31) and one hydrolysed tannin (32). Compounds 4 and 29 are isolated for the first time from the species, while compounds 3, 7, 20, 22, 23, 24, 25, 26, 28, 30 are reported for the first time in Juglandaceae. Chemotaxonomic significance of isolated compounds into Junglandaceae family is thoroughly discussed.     

Somatostatin-14 influences pituitary–ovarian axis in peripubertal rats

The effects of multiple somatostatin (SRIH-14) administration on the pituitary-ovarian axis were examined in peripubertal rats. Female Wistar rats received subcutaneously, two daily doses of 20 mug SRIH-14 per 100 g body weight (b.w.) for five consecutive days (from the 33rd to the 37th day of life). Follicle-stimulating (FSH), luteinizing (LH) and somatotropic (GH) cells were examined by the peroxidase-anti-peroxidase immunocytochemical method. Changes in cell volumes, volume densities and number per unit area (mm(2)) of FSH-, LH- and GH-immunoreactive cells were evaluated by stereology and morphometry. Serum FSH and LH levels were determined by RIA. Ovaries were analyzed by simple point counting of follicles. The volumes and volume densities of FSH-, LH- and GH-immunoreactive cells were significantly decreased while their numbers per mm(2) remained unchanged. SRIH-14 induced a significant decrease in serum FSH and LH levels. In the ovary, SRIH-14 induced an increase in the number of primordial follicles, followed by a reduction in the number of small healthy growing follicles and absence of preovulatory follicles. The number of atretic follicles was unchanged. We concluded that treatment with SRIH-14 during the peripubertal period markedly inhibited pituitary FSH, LH and GH cells. In the ovary, SRIH-14 acted by inhibiting folliculogenesis without affecting atretic processes.     

Genotypic and phenotypic evaluation of Rutilus spp. from Skadar, Ohrid and Prespa Lakes supports revision of endemic as well as taxonomic status of several taxa

One mtDNA gene (cytochrome b), one nuclear DNA fragment, five microsatellites and a suite of morphological characters were evaluated in samples of Rutilus spp. from Skadar, Ohrid and Prespa Lakes. Both genetic and phenotypic data supported two sympatric taxa in Lake Skadar, whereby Prespa and Ohrid Lakes revealed only a single taxon each. One of the taxa from Lake Skadar was similar to samples from Lake Prespa, whereas the second taxon was the most divergent in the data set. The estimated time to the most recent common ancestor of these two sympatric taxa in Lake Skadar was between 125 000 and 500 000 years. The data did not support existing taxonomic schemes for Rutilus in these lakes. This study poses the following working hypothesis: (1) Rutilus prespensis lives both in Lake Prespa and Lake Skadar and therefore is not endemic to Lake Prespa, (2) Rutilus ohridanus lives in Lake Ohrid only and therefore could be considered an endemic if its species status is retained and (3) a third recently described taxon (Rutilus albus) sympatric to R. prespensis lives in Lake Skadar.