Responses of Black-headed Gulls Larus ridibundus to conspecific brood parasitism

Conspecific brood parasitism in birds occurs when a female inserts her egg into the clutch of her own species. If successful, i.e. the parasitic egg is accepted by the host, then the host female or pair rears the offspring of the parasite. In the present study, we studied natural conspecific brood parasitism in Black-headed Gulls (Larus ridibundus), and conducted series of the experiments with mimetic (conspecific) and non-mimetic (conspecific painted light blue) eggs to explore responses of the tested pairs towards these alien eggs. The natural parasitism rate was 10% and the probability of being parasitized significantly increased with nest density. Experimentally parasitized pairs rejected both types of experimental eggs at a similar rate: 14.3 % for mimetic and 25.5% for non-mimetic within 2 days. Non-mimetic eggs were more selectively rejected than mimetic eggs. The relationships between the probability of egg rejection (dependent variable) and predictor (independent) variables were examined by fitting generalized linear models. Contrast and intraclutch variation in ground color and spotting pattern and the volume of the egg had no significant effect on rejection behavior in either non-mimetic or mimetic eggs. However, nest density significantly positively affected rejection behavior of the Black-headed Gulls in both non-mimetic and mimetic treatments.     

Effects of novel maleimide derivatives on cell cultures with different properties

The paper is focused on pilot study of effects of novel synthetic protein kinase inhibitors—maleimide derivatives in different concentrations on normal, transformed and multipotent cell lines. Influence on cell proliferation and morphological characteristics has been demonstrated. The chosen agents cause antiproliferative effect on transformed cells and are not cytotoxic to normal cell lines. Moreover, different maleimide derivatives’ effects on multipotent cells in attached and floating states has been shown. Described results can be used for further research of the maleimide derivatives as antitumor agents.     

Species-specific SSR alleles for studies of hybrid cattails (Typha latifolia x T. angustifolia; Typhaceae) in North America

? Premise: Studies of hybridizing species are facilitated by the availability of species-specific molecular markers for identifying early- and later-generation hybrids. Cattails are a dominant feature of wetland communities, and a better understanding of the prevalence of hybrids is needed to assess the ecological and evolutionary effects of hybridization. Hybridization between Typha angustifolia and T. latifolia produce long-lived clones, known as Typha ×glauca, which are considered to be invasive. Although morphological variation in cattails makes it difficult to recognize early- and later-generation hybrids, several dominant, species-specific RAPD markers are available. Our goal was to find codominant, species-specific markers with greater polymorphism than RAPDs, to identify later-generation hybrids more efficiently. ? Methods: We screened nine SSR (simple sequence repeat) loci that were described from populations in Ukraine, and we surveyed 31 cattail populations from the upper Midwest and eastern USA. ? Key results: Seven SSR loci distinguished the parent taxa and were consistent with known species-specific RAPD markers, allowing easier detection of backcrossing. We used linear discriminant analysis to show that F(1) hybrid phenotypes were intermediate between the parent taxa, while those of backcrossed plants overlapped with the hybrids and their parents. Log(leaf length/leaf width), spike gap length, spike length, and stem diameter explained much of the variation among groups. ? Conclusions: We provide the first documentation of backcrossed plants in hybridizing cattail populations in Michigan. The diagnostic SSR loci we identified should be extremely useful for examining the evolutionary and ecology interactions of hybridizing cattails in North America.     

Synthesis,physico-chemical properties and penetration activity of alkyl-6-(2,5-dioxopyrrolidin-1-yl)-2-(2-oxopyrrolidin-1-yl)hexanoates as potential transdermal penetration enhancers

Skin penetration enhancers are used to allow formulation of transdermal delivery systems for drugs that are otherwise insufficiently skin-permeable. The series of seven esters of substituted 6-aminohexanoic acid as potential transdermal penetration enhancers was formed by multistep synthesis. The synthesis of all newly prepared compounds is presented here. Structure confirmation of all generated compounds was accomplished by ¹H NMR, ¹³C NMR, IR and MS spectroscopy. All the prepared compounds were analyzed using RP-HPLC method for the lipophilicity measurement and their lipophilicity (log k) was determined. Hydrophobicities (log P/C log P) of the studied compounds were also calculated using two commercially available programs and 3D structures of the selected compounds were investigated by means of ab initio/DFT calculations of geometry. All the synthesized esters were tested for their in vitro transdermal penetration enhancer activity. The relationships between the lipophilicity and the chemical structure (SLR) of the studied compounds as well as the relationships between their chemical structure and transdermal penetration activity are mentioned.     

Light-dependent PER-like proteins in the cephalic ganglia of an apterygote and a pterygote insect species

Antibodies targeted to a highly conserved tetradecapeptide region of the pivotal biological clock protein PER detect in the firebrat Thermobia domestica a 115-kDa protein and in the cockroach Periplaneta americana a 110-kDa protein that are present in the cytoplasm of a small set of brain cells. A similar cytoplasmic reaction occurs with antisera to the whole PER protein of Drosophila melanogaster, but these antisera also react with numerous cell nuclei. On western blots, they detect an 80-kDa antigen in T. domestica and 70- and 80-kDa antigens in P. americana. No indication of antigen translocation between cell nuclei and cytoplasm was found. Nuclear staining is maintained at a high constant level in T. domestica held at a 12:12 h light:dark photoperiod (LD) or in continuous light, but disappears rapidly in response to extended darkness. In P. americana under LD conditions, the number of immunoreactive nuclei and their staining intensity fluctuate in parallel, with maximal staining late in the day. The circadian changes are maintained in continuous light but all staining vanishes in continuous darkness. A 6-h light pulse in early night of an LD cycle induces maximal staining after about 10 h, suggesting that the effect of light on nuclear PER-like expression is indirect. The behaviour of nuclear antigens is opposite to that of the cytoplasmic PER-like proteins that persist in constant darkness and disappear in constant light. Under LD conditions, the cytoplasmic PER-like antigen cycles in T. domestica but remains at a steady level in P. americana. The sensitivity to photoregime suggests that both the nuclear and the cytoplasmic PER-like antigens are components of the biological clock.R. Závodská and H. Sehadová contributed equally to this work     

Genome size variation and species relationships in Hieracium sub-genus Pilosella (Asteraceae) as inferred by flow cytometry

BACKGROUND AND AIMS: Hieracium sub-genus Pilosella (hawkweeds) is a taxonomically complicated group of vascular plants, the structure of which is substantially influenced by frequent interspecific hybridization and polyploidization. Two kinds of species, 'basic' and 'intermediate' (i.e. hybridogenous), are usually recognized. In this study, genome size variation was investigated in a representative set of Central European hawkweeds in order to assess the value of such a data set for species delineation and inference of evolutionary relationships. METHODS: Holoploid and monoploid genome sizes (C- and Cx-values) were determined using propidium iodide flow cytometry for 376 homogeneously cultivated individuals of Hieracium sub-genus Pilosella, including 24 species (271 individuals), five recent natural hybrids (seven individuals) and experimental F(1) hybrids from four parental combinations (98 individuals). Chromosome counts were available for more than half of the plant accessions. Base composition (proportion of AT/GC bases) was cytometrically estimated in 73 individuals. KEY RESULTS: Seven different ploidy levels (2x-8x) were detected, with intraspecific ploidy polymorphism (up to four different cytotypes) occurring in 11 wild species. Mean 2C-values varied approx. 4.3-fold from 3.53 pg in diploid H. hoppeanum to 15.30 pg in octoploid H. brachiatum. 1Cx-values ranged from 1.72 pg in H. pilosella to 2.16 pg in H. echioides (1.26-fold). The DNA content of (high) polyploids was usually proportional to the DNA values of their diploid/low polyploid counterparts, indicating lack of processes altering genome size (i.e. genome down-sizing). Most species showed constant nuclear DNA amounts, exceptions being three hybridogenous taxa, in which introgressive hybridization was suggested as a presumable trigger for genome size variation. Monoploid genome sizes of hybridogenous species were always between the corresponding values of their putative parents. In addition, there was a good congruency between actual DNA estimates and theoretical values inferred from putative parental combinations and between DNA values of experimental F(1) hybrids and corresponding established hybridogenous taxa. CONCLUSIONS: Significant differences in genome size between hawkweed species from hybridogenous lineages involving the small-genome H. pilosella document the usefulness of nuclear DNA content as a supportive marker for reliable delineation of several of the most problematic taxa in Hieracium sub-genus Pilosella (including classification of borderline morphotypes). In addition, genome size data were shown to have a good predictive value for inferring evolutionary relationships and genome constitution (i.e. putative parental combinations) in hybridogenous species.