Discovery of P2X3 selective antagonists for the treatment of chronic pain

Purinergic receptor P2X3 has been linked to analgesia in a number of pre-clinical models of pain, and is expressed in the human pain perception pathway. Only few P2X3-selective antagonists have been reported to date. This Letter describes the SAR and in vivo analgesic profile of a novel scaffold of selective P2X3 antagonists.     

Central carbon metabolism influences fidelity of DNA replication in Escherichia coli

Recent studies indicated that there is a direct link between central carbon metabolism (CCM) and initiation and elongation of DNA replication in Eschericha coli. Namely, effects of certain mutations in genes coding for replication proteins (dnaA, dnaB, dnaE, dnaG, and dnaN) could be specifically suppressed by deletions of some genes, whose products are involved in CCM reactions (pta, ackA, pgi, tktB, and gpmA). Here, we demonstrate that the link between CCM and DNA synthesis can be extended to the DNA replication fidelity, as we report changes of the mutator phenotypes of E. coli dnaQ49 and dnaX36 mutants (either suppression or enhancement) by dysfunctions of zwf, pta, ackA, acnB, and icdA genes. Overexpression of appropriate wild-type CCM genes in double mutants resulted in reversions to the initial mutator phenotypes, indicating that the effects were specific. Moreover, the observed suppression and enhancement effects were not caused by changes in bacterial growth rates. These results suggest that there is a genetic correlation between CCM and DNA replication fidelity in E. coli, apart from the already documented link between CCM and DNA replication initiation control and elongation efficiency.     

Is callose a barrier for lead ions entering <Emphasis Type="Italic">Lemna minor</Emphasis> L. root cells?

Plants have developed a range of strategies for resisting environmental stresses. One of the most common is the synthesis and deposition of callose, which functions as a barrier against stress factor penetration. The aim of our study was to examine whether callose forms an efficient barrier against Pb penetration in the roots of Lemna minor L. exposed to this metal. The obtained results showed that Pb induced callose synthesis in L. minor roots, but it was not deposited regularly in all tissues and cells. Callose occurred mainly in the protoderm and in the centre of the root tip (procambial central cylinder). Moreover, continuous callose bands, which could form an efficient barrier for Pb penetration, were formed only in the newly formed and anticlinal cell walls (CWs); while in other CWs, callose formed only small clusters or incomplete bands. Such an arrangement of callose within root CWs inefficiently protected the protoplast from Pb penetration. As a result, Pb was commonly present inside the root cells. In the light of the results, the barrier role of callose against metal ion penetration appears to be less obvious than previously believed. It was indicated that induction of callose synthesis is not enough for a successful blockade of the stress factor penetration. Furthermore, it would appear that the pattern of callose distribution has an important role in this defence strategy.     

Antiproliferative activity of salinomycin and its derivatives

Antiproliferative activity of seven amides and one benzotriazole ester derivative of salinomycin, a polyether ionophore antibiotic, with recently reported antibacterial activity, are herein described. Salinomycin and the majority of derivatives exhibit potent antiproliferative activity against the drug-resistant cancer cell lines. Moreover almost all derivatives show stronger activity against LoVo/DX cell line than that of unmodified salinomycin.     

Organelle evolution: Paulinella breaks a paradigm

It is commonly assumed that transformations of endosymbionts into organelles are exceptionally rare evolutionary events because of hypothetical difficulties in the origin of an import apparatus for nuclear-encoded, organelle-targeted proteins along with their targeting signals. A challenge to this view comes from recent studies of protein import into the cyanobacterial endosymbionts/organelles of Paulinella chromatophora.     

Long-term changes in numbers of geese stopping over and wintering in south-western Poland

South-western Poland belongs to the key staging areas for geese in Europe, supporting some 100000 birds in recent years. We compared goose counts conducted in the 1970s, 1990s and during 2009–2011 in this region, and linked the findings to the recent assessments of trends in the flyway-populations. Numbers increased several dozen times between the first two counts and have stabilized to the present. More than 14% of the flyway Tundra Bean Goose (Anser fabalis rossicus) stopped over in SW Poland on passage. Smaller numbers of White-fronted Goose (A. albifrons), Greylag Goose (A. anser), and four other rarer species, have all increased since the 1970s. The likely factors responsible for these changes are mild weather conditions, increased availability of large water bodies and shifts in winter ranges of particular species. Temporal mismatch between SW Poland and the total flyways in Bean and White-fronted Geese was recorded when we compared the long-term and the short-term population trends. Increasing reports of other species in SW Poland match the general tendencies in Europe. These data document that regional trends are not a simple reflection of those in flyways as a whole. To understand changes in goose populations a re-established international count network is desired.     

Endozoochorous dispersal of alien and native plants by two palearctic avian frugivores with special emphasis on invasive giant goldenrod <Emphasis Type="Italic">Solidago gigantea</Emphasis>

The role of frugivorous birds in dispersal of the seeds of fleshy-fruited plants is well understood, but other groups of birds like granivores and omnivores can also act as vectors, especially in the process of non-standard dispersal. In this study we examined the role of two widely distributed birds (the Eurasian Blackbird, Turdus merula, and the Black Redstart, Phoenicurus ochruros) in seed dispersal. We analyzed the content of 279 droppings of the Black Redstart collected between July and October and 85 droppings of the Eurasian Blackbird collected during January. In total we found 366 seeds, representing 11 plant taxa, in the faecal samples; 93% of the seeds belonged to fleshy-fruited species. The most numerous were two native taxa, Sambucus racemosa/nigra, in summer and autumn, Crataegus monogyna in winter, and one alien species Morus alba, which is dispersed in summer. We also found seeds of four dry-fruited species; the most interesting of which was the presence of anemochorous seeds of Solidago gigantea (a highly invasive alien species). The seeds were found only in droppings of the Eurasian Blackbird. Considering the obtained results the need for further studies on bird-plant interactions should be a priority.