Independent colonization of multiple urban centres by a formerly forest specialist bird species

Urban areas are expanding rapidly, but a few native species have successfully colonized them. The processes underlying such colonization events are poorly understood. Using the blackbird Turdus merula, a former forest specialist that is now one of the most common urban birds in its range, we provide the first assessment of two contrasting urban colonization models. First, that urbanization occurred independently. Second, that following initial urbanization, urban-adapted individuals colonized other urban areas in a leapfrog manner. Previous analyses of spatial patterns in the timing of blackbird urbanization, and experimental introductions of urban and rural blackbirds to uncolonized cities, suggest that the leapfrog model is likely to apply. We found that, across the western Palaearctic, urban blackbird populations contain less genetic diversity than rural ones, urban populations are more strongly differentiated from each other than from rural populations and assignment tests support a rural source population for most urban individuals. In combination, these results provide much stronger support for the independent urbanization model than the leapfrog one. If the former model predominates, colonization of multiple urban centres will be particularly difficult when urbanization requires genetic adaptations, having implications for urban species diversity.     

Calorimetric studies of the effect of cis-carotenoids on the thermotropic phase behavior of phosphatidylcholine bilayers

Carotenoid geometry is a factor that determines their solubility and orientation in the lipid membrane as well as antioxidant capacities and bioavailability. The effects of the cis-isomers of carotenoids (zeaxanthin and β-carotene) on the thermotropic properties of lipid membranes formed with dimyristoylphosphatidylcholine (DMPC) and dipalmitoylphosphatidylcholine (DPPC) were investigated by means of differential scanning calorimetry. The results were compared with the effects caused by the all-trans-isomer. Both the trans and cis isomers of zeaxanthin shifted the main phase transition temperature to lower values and decreased the cooperativity of the phase transition. The effect of all-trans zeaxanthin on the physical properties of the lipid bilayers has been shown to strongly depend on the hydrocarbon chain length of the membrane. In the case of cis-zeaxanthin this relationship is weaker.     

Direct observation to chemokine receptor 5 on T-lymphocyte cell surface using fluorescent metal nanoprobes

Chemokine receptor 5 (CCR5) is a cell surface protein required for HIV-1 infection. It is important to detect the amount and observe the spatial distribution of the CCR5 receptors on the cell surfaces. In this report, we describes the metal nanoparticles which were specially designed as molecular fluorescent probes for imaging of CCR5 receptors on the T-lymphocytic PM1 cell surfaces. These CCR5 monoclonal antibodies (mAbs) metal complexes were prepared by labeling mAbs with Alexa Fluor 680 followed by covalent binding the labeled mAbs on the 20 nm silver nanoparticles. Compared with the labeled mAbs without metal, the mAb-metal complexes were found to display enhanced emission intensity and shortened lifetime due to interactions between fluorophores and metal. The mAb-metal complexes were incubated with the PM1 cell lines. The confocal fluorescent intensity and lifetime cell images were recorded on single cells. It was observed that the mAb-metal complexes could be clearly distinguished from the cellular autofluorescence. By analyzing a pool of cell images, we observed that most CCR5 receptors appeared as clusters on the cell surfaces. The fluorophore-metal complexes developed in this report are generally useful for detection of cell surface receptors and provide a new class of probe to study the interaction between the CCR5 receptors with viral gp120 during HIV infections.     

An endogenous RNA-synthesis-promoting oligopeptide from Cucurbita pepto var. patissonina

The effect of CPPTI (Cucurbita pepo patissonina trypsin inhibitor) on the growth of Cucurbita pepo var patissonina (White bush) was examined. Plants treated with CPPTI grew faster than untreated plants and similarly to those treated with gibberellic acid. Isolated cell nuclei from plants treated with CPPTI showed that of the three DNA-dependent RNA polymerases assayed, RNA polymerase I (EC2.7.7.6) activity was preferentially elevated.Abbreviations CPPTI Cucurbita pepo patissonina trypsin inhibitor - GA₃ gibberellic acid - IAA indole-3-acetic acid - kDa kilodalton - RP I DNA-dependent RNA polymerase I     

Template-directed synthesis on short oligoribocytidylates

Summary The oligonucleotides C(pC)_n, n=4, 5, 6, 7, are efficient templates for the oligomerization of guanosine-5-phospho-2-methylimidazole (2-MeImpG). They yield oligomeric products that are substantially less regiospecific than those obtained on polycytidylate [poly(C)]. The overall distributions of products obtained on oligo(C)s are generally similar to those of products obtained on oligodeoxycytidylates [oligo(dC)s], but there are substantial differences in the ratios of isomers.The 3–5-linked dinucleoside monophosphate GpG efficiently initiates oligomer formation with 2-MeImpG on oligo(C) templates. The pattern of products obtained by chain extension parallels closely that of products obtained directly from 2-MeImpG, except that the former products lack the 5-terminal phosphate group.     

Transport of proteins from cytoplasm into plastids in chloramphenicol-treated bean leaf discs

Leaf discs from etiolated bean plants were found to incorporate [³H]lysine into 80 S ribosomesynthesized proteins in the presence of chloramphenicol (100 mg l^–1) when exposed to light. After a 7 min pulse of [³H]lysine, the discs were transferred to the same medium but with nonradioactive lysine, and postincubation was carried out for 24 h. The number of silver grains over the plastids, after the first period of a lag phase, indicates a large increase between 12 and 24 h of postincubation. Simultaneously, the labeling of the cytoplasm becomes reduced during that period. The results show that during inhibition of the protein formation within plastids, the synthesis of plastid-destined proteins in cytoplasm, as well as their transport into plastids, can still proceed.     

Paleoecology of the Miocene fossil mammal fauna from Bełchatów (Poland)

Miocene fauna of land mammals is known from numerous fossil localities in western Europe but its remains are rare in the north-eastern part of this continent. The open brown coal mine at Bełchatów in central Poland revealed numerous remains of small and large mammals representing three Miocene biozones from MN4 to MN8/9. They indicate the presence of relatively stable subtropical conditions during all the time of the Miocene deposition in the Bełchatów basin with only slight cooling before the end of the sedimentation.

     

Monomethylarsonate (MMAv) exerts stronger effects than arsenate on the structure and thermotropic properties of phospholipids bilayers

Methylation of inorganic arsenic has been regarded as a detoxification mechanism because its metabolites monomethylarsonic acid (MMA(v)) and dimethylarsinic acid (DMA(v)) are supposed to be less toxic than inorganic arsenite and arsenate. In recent years, however, this interpretation has been questioned. Additionally, there are insufficient reports concerning the effects of arsenic compounds on cell membrane structure and functions. With the aim to better understand the molecular mechanisms of the interaction of MMA(v) and arsenate with cell membranes, we have utilized molecular models consisting in bilayers of dimyristoylphosphatidylcholine (DMPC) and dimyristoylphosphatidylethanolamine (DMPE), representative of phospholipid classes located in the outer and inner monolayers of many cell membranes including that of the human erythrocyte. The capacity of MMA(v) and arsenate to perturb the bilayer structures of DMPC and DMPE was evaluated by X-ray diffraction; the modifications of their thermotropic behavior were followed by differential scanning calorimetry (DSC), while DMPC large unilamellar vesicles (LUV) were studied by fluorescence spectroscopy. It was found that MMA(v) and arsenate did not structurally perturb DMPC bilayers; however, DMPE bilayers did suffer structural perturbations by MMA(v). DSC measurements also revealed that DMPE's thermotropic properties were significantly affected by arsenicals, where MMA(v) was more effective than arsenate, whilst only slight modifications were observed in the case of DMPC-MMA(v) system.     

TGF-beta1 gene polymorphisms influence the course of the disease in non-Hodgkin's lymphoma patients

Non-Hodgkin's lymphomas (NHL) constitute a heterogenous group of mainly B-cell lymphoproliferative diseases with different patterns of clinical behaviour. Biological mechanisms leading to development of NHL are not clearly understood. Transforming growth factor-beta1 (TGF-beta1) influences B cell growth and development. The present study aimed to determine whether there is an association between the polymorphic features located within the TGF-beta1 gene in NHL patients and progression of the disease. Two single nucleotide polymorphisms at positions 869 T/C (Leu10Pro) and 915 G/C (Arg25Pro) in the precursor region of the TGF-beta1 gene were determined in 55 NHL patients and 50 healthy individuals by PCR-SSP technique using commercial primers. In univariate analysis the presence of TGF-beta1 high producer genotypes (T/T G/G or T/C G/G) was found to significantly associate with an increased number of extranodal sites (11/30 vs 3/25, p=0.035 for two or more extranodal sites in patients having or lacking the TGF-beta1 high producer genotype, respectively). TGF-beta1 high producer genotype together with other clinical and biological factors (patient sex and age, stage and aggressiveness of the disease, presence of B symptoms, serum LDH level) were subjected to multivariate logistic regression analyses for the number of extranodal sites. Multivariate analysis confirmed the role of TGF-beta1 high producer genotype as a risk factor of NHL manifestation in two or more extranodal sites (OR=7.217, p=0.043) in addition to histological aggressiveness of the disease (OR=4.302, p=0.057). TGF-beta1 gene polymorphisms were found to associate with the course of the disease in NHL patients. TGF-beta1 high producer genotype appeared as an independent risk factor of extranodal manifestation of the disease.     

Relationships between silicon content and glutathione peroxidase activity in tissues of rats receiving lithium in drinking water

Lithium salts are widely used in psychiatry, but their presence in organism can result in both beneficial and adverse effects. Silicon, the third most abundant trace element in humans as well as antioxidant enzyme glutathione peroxidase (GPx) play important roles in organism. The disturbance of their level can cause severe disorders. The aim of our work was to evaluate the influence of Li₂CO₃ administration in drinking water for a period of 4 weeks on Si content and GPx activity in the tissues of liver, kidney, brain and femoral muscle in rats. The concentrations of provided solutions were 0.7, 1.4, 2.6, 3.6, 7.1 and 10.7 mmol Li⁺·dm⁻³. GPx activity was decreased versus control as a consequence of Li treatment, particularly in kidney and brain. This effect could be suggested to contribute to renal abnormalities which could occur during Li therapy. Si tissue level was significantly enhanced versus control in liver and femoral muscle in groups receiving high Li doses. In brain no well-marked changes were observed, whereas in kidney we observed the depletion in low-Li-groups, restoration of Si level in higher-Li-groups and unexpected decrease in the highest-Li-group. Positive correlations between Si content and GPx activity in the tissues of kidney (r = 0.677) and brain (r = 0.790) as well as negative correlation (r = −0.819) in femoral muscle were found. We consider that our results give some reason for suggesting that monitoring of silicon level in patients undergoing Li therapy could be recommended. However, more investigations should be performed, particularly regarding the relationships between Si and GPx in blood and urine Si excretion during lithium administration.