Fitness consequences of longer breeding seasons of a migratory passerine under changing climatic conditions.

Numerous studies have shown that climate change affects the timing of migration and bird laying dates, but the resulting changes in the duration of breeding seasons and their fitness consequences remain largely unknown. We compared breeding parameters of 343 individually marked female Eurasian reed warblers, a multi-brooded migratory passerine, studied in the same area in 1980-1983 and 2005-2012. The latter period was warmer, with mean temperatures during the breeding season higher by 1.5°C on average. As, in recent years, birds arrive earlier from wintering areas and the breeding season of the population is longer, we hypothesized it should result in the increased re-nesting opportunities of individual females. We found that breeding periods of individual females (from building of the first nest till the end of caring for last fledglings/last nest failure) in the current century have extended by 2 weeks compared to the 1980s. In the 2000s, females produced 75% more fledglings annually than females in the 1980s (2.8 vs. 1.6, respectively). The proportion of females raising second broods increased from 2.7% to 23.6% between the first and the second study period while the share of females that did not produce any young annually decreased from 48.1% to 15.5%. The higher offspring production in recent years was related to more successfully fledged broods and an earlier start of breeding, which secured more time to re-nest. Higher female parental effort in recent years was not manifested in the reduction of the female apparent survival: it was almost identical in the two study periods (0.30 vs. 0.31). We conclude that prolonged reproductive seasons might be beneficial for some species. Identifying causes and consequences of changes in the duration of breeding seasons may be essential to predict demography of populations under changing climatic conditions.

Recombinant immunotoxin targeting GPC3 is cytotoxic to H446 small cell lung cancer cells.

Glypican-3 (GPC3) is a cell membrane glycoprotein that regulates cell growth and proliferation. Aberrant expression or distribution of GPC3 underlies developmental abnormalities and the development of solid tumours. The strongest evidence for the participation of GPC3 in carcinogenesis stems from studies on hepatocellular carcinoma and lung squamous cell carcinoma. To the best of our knowledge, the role of the GPC3 protein and its potential therapeutic application have never been studied in small cell lung carcinoma (SCLC), despite the known involvement of associated pathways and the high mortality caused by this disease. Therefore, the aim of the present study was to examine GPC3 targeting for SCLC immunotherapy. An immunotoxin carrying an anti-GPC3 antibody (hGC33) and Pseudomonas aeruginosa exotoxin A 38 (PE38) was generated. This hGC33-PE38 protein was overexpressed in E. coli and purified. ADP-ribosylation activity was tested in vitro against eukaryotic translation elongation factor 2. Cell internalisation ability was confirmed by confocal microscopy. Cytotoxicity was analysed by treating liver cancer (HepG2, SNU-398 and SNU-449) and lung cancer (NCI-H510A, NCI-H446, A549 and SK-MES1) cell lines with hGC33-PE38 and estimating viable cells number. A BrdU assay was employed to verify anti-proliferative activity of hGC33-PE38 on treated cells. Fluorescence-activated cell sorting was used for the detection of cell membrane-bound GPC3. The hGC33-PE38 immunotoxin displayed enzymatic activity comparable to native PE38. The protein was efficiently internalised by GPC3-positive cells. Moreover, hGC33-PE38 was cytotoxic to HepG2 cells but had no effect on known GPC3-negative cell lines. The H446 cells were sensitive to hGC33-PE38 (IC50, 70.6±4.6 ng/ml), whereas H510A cells were resistant. Cell surface-bound GPC3 was abundant on the membranes of H446 cells, but absent on H510A. Altogether, the present findings suggested that GPC3 could be considered as a potential therapeutic target for SCLC immunotherapy.

Ecological niche partitioning in a fragmented landscape between two highly specialized avian flush-pursuit foragers in the Andean zone of sympatry.

In the Andes, pairs of ecologically similar species are often separated by narrow elevational sympatry zones but the mechanisms mediating sympatry are not fully understood. Here, we describe niche partitioning within a sympatry zone in a fragmented Andean landscape between two closely related flush-pursue species: a high-elevation montane forest dweller, (Myioborus melanocephalus), and a mid-elevation montane forest dweller, (M. miniatus). As all flush-pursuers use very similar hunting techniques involving visual displays to flush and pursue insects in air, and benefit from being the "rare predators", ecological sorting between species in sympatry zones should allow their co-existence. We found that both species occupied vegetation resembling their typical allopatric habitats: a mosaic of pastures, clearings, and shrubs with small proportion of high trees for M. melanocephalus, and dense high forests with high proportion of trees, lower irradiance and higher humidity for M. miniatus. M. melanocephalus often foraged in bushes and at lower heights, whereas M. miniatus often foraged in tree crowns. The two species differed relatively little in their foraging technique. These results demonstrate how ecological sorting permits species of divergent elevational distributions and habitats to successfully coexist in sympatric zones where habitat diversity allows both species to find their preferred habitat.

Does heavy metal exposure affect the condition of Whitethroat (Sylvia communis) nestlings?

Anthropogenic pollution results in high concentrations of heavy metals in the environment. Due to their persistence and a high potential for bioaccumulation, metals are a real threat for birds breeding in industrial areas. The aim of the present study has been to explore the contents of heavy metals (arsenic As, cadmium Cd, chromium Cr, copper Cu, iron Fe, nickel Ni, lead Pb and zinc Zn) in the excreta of Whitethroat (Sylvia communis) nestlings living in polluted environment and to investigate the relationship between these contents and the nestlings' condition. Excrement samples contained all the studied elements. The contents of arsenic, cadmium, copper and zinc in the excreta of nestlings from nests located close to a slag dump were several times higher than in the soil near the dump, which suggested accumulation in food consumed by the birds. Condition parameters (body mass and haemoglobin concentration) were not related to heavy metal concentrations in the nestlings' excreta, except of Zn. It is possible that Whitethroats are able to detoxicate heavy metals to a certain extent. Detailed, multi-element analysis of the environment, food and bird tissues or excreta should be performed to explore relations between different chemicals and bird condition.

Habitat-specific sensory-exploitative signals in birds: propensity of dipteran prey to cause evolution of plumage variation in flush-pursuit insectivores.

Sensory exploitation occurs when signals trigger behavioral reactions that diminish the receiver's fitness. Research in this area focuses on the match between the signal's form and the receiver's sensitivity, but the effect of habitat on interspecific sensory exploitation is rarely addressed. Myioborus redstarts use conspicuous wing and tail displays of contrasting black-and-white plumage patches to flush dipteran insects, which are then pursued and captured in flight. Previous studies have shown that by increasing the distance at which insects perform an escape response, conspicuous visual displays improve the birds' foraging performance. We tested the hypothesis that selection for a visual signal that maximizes prey escape distance under local habitat conditions can lead to the evolution of geographic variation in plumage pattern among Myioborus redstarts. Using models of foraging birds, we recorded the escape responses of Dipterous insects to a range of plumage patterns and background tones (from light to dark) to determine whether the plumage pattern that maximizes prey flushing is dependent upon that habitat (background) against which birds are viewed by their prey. Our results indicate that the effectiveness of a particular plumage pattern in flushing dipteran prey depends strongly on the background against which that plumage pattern is displayed, and darker habitat (background) conditions generally favor plumages with more extensive patches of white in the tail. However, the addition of white wing patches that imitate the plumage of the painted redstart (Myioborus pictus) generally increases insect escape responses but reduces the effect that tail pattern variation and background tone have on escape behavior. These experiments support the hypothesis that habitat-specific natural selection to enhance sensory exploitation of prey escape responses could produce geographic variation in plumage patterns of flush-pursuers.

Towards Engineering Novel PE-Based Immunotoxins by Targeting Them to the Nucleus.

Exotoxin A (PE) from Pseudomonas aeruginosa is a bacterial ADP-ribosyltransferase, which can permanently inhibit translation in the attacked cells. Consequently, this toxin is frequently used in immunotoxins for targeted cancer therapies. In this study, we propose a novel modification to PE by incorporating the NLS sequence at its C-terminus, to make it a selective agent against fast-proliferating cancer cells, as a nucleus-accumulated toxin should be separated from its natural substrate (eEF2) in slowly dividing cells. Here, we report the cytotoxic activity and selected biochemical properties of newly designed PE mutein using two cellular models: A549 and HepG2. We also present a newly developed protocol for efficient purification of recombinant PE and its muteins with very high purity and activity. We found that furin cleavage is not critical for the activity of PE in the analyzed cell lines. Surprisingly, we observed increased toxicity of the toxin accumulated in the nucleus. This might be explained by unexpected nuclease activity of PE and its potential ability to cleave chromosomal DNA, which seems to be a putative alternative intoxication mechanism. Further experimental investigations should address this newly detected activity to identify catalytic residues and elucidate the molecular mechanism responsible for this action.

Cobalt(II) octacyanotungstate(V) organic-inorganic hybrid ferromagnetic materials with pyrazine and 4,4'-bipyridine.

Two new ferromagnetic organic-inorganic hybrid materials [Co(II)3(H2O)6(pyz)3[W(V)(CN)8]2].3.5H2O (1) and [Co(II)3(H2O)4(4,4'-bpy)3[W(V)(CN)8]2].1.5(4,4'-bpy).6H2O (2) have been synthesised and characterised. The structure of the compounds have been investigated combining EXAFS (extended X-ray absorption fine structure), ES-MS (electrospray mass spectrometry), IR (infrared spectroscopy), UV-VIS electronic spectroscopy and TGA (thermogravimetric analysis) coupled with QMS (quadrupole mass spectrometer) experiments. The studies reveal that both compounds consist of Co(II)-NC-W(V) and Co(II)-L-Co(II) linkages (L = pyrazine (1) or 4,4-bipyridine (2)). Both networks are created by cyano-bridged Co(II)3W(V)2 chains joined by organic linkers into a 2D architecture. A difference of cobalt coordination numbers in both compounds derived from EXAFS study is consistent with the ES-MS conclusion. The ac magnetic characterisation exhibits the transition to the ferromagnetic phase at T(C) = 26 K (1) and to the spin glass-like phase at T(G) = 16 K (2). The frequency dependent chi'(T) and chi''(T) signals indicate the presence of some disorder in spin alignment below ordering temperatures. Both networks are also characterised a by magnetic hysteresis loop of coercive field H(c) = 750 Oe (1) and 1200 Oe (2) at T = 4.2 K.