Migratory orientation of sedge warblers (Acrocephalus schoenobaenus) in relation to eating and exploratory behaviour

Orientation tests performed with Emlen funnels show much variation. This scatter in responses can be partially explained by considering the birds’ personalities.We studied a Passerine migrant, the Sedge Warbler (Acrocephalus schoenobaenus), on autumn passage at Kalimok Biological Station, Bulgaria. Birds caught in the morning were kept in cages with known and regularly controlled amounts of food. In the evening they were tested for orientation, the next morning they were observed for 3 min in an unfamiliar cage, then released.Birds that ate on the first day oriented in the expected, southward direction, non-eating birds were scattered.Eating behaviour was related to the exploration pattern on the next day. Eating birds moved and flew less, hopped, looked around and explored the cage more, and were quicker in eating a food item if present.Lean birds ate and explored more but also oriented better, contrary to expectations where fat reserves indicate readiness for migration. A hypothesis is discussed where fat, migration and personality may be linked.Personality aspects may influence the individuals’ ability to cope with an experimental situation and influence the outcome of the tests, therefore its analysis can help in predicting the birds’ performance in apparently unrelated experiments.     

Study of the thermal stability of D-amino acid oxidase from Trigonopsis variabilis reveals enzyme inactivation via multiple steps

The thermal stability of a highly purified preparation of D-amino acid oxidase from Trigonopsis variabilis (TvDAO), which does not show microheterogeneity due to the partial oxidation of Cys-108, was studied based on dependence of temperature (20-60°C) and protein concentration (5-100 µmol L^-1). The time courses of loss of enzyme activity in 100 mmol L^-1 potassium phosphate buffer, pH 8.0, are well described by a formal kinetic mechanism in which two parallel denaturation processes, partial thermal unfolding and dissociation of the FAD cofactor, combine to yield the overall inactivation rate. Estimates from global fitting of the data revealed that the first-order rate constant of the unfolding reaction (k _a) increased 10⁴-fold in response to an increase in temperature from 20 to 60°C. The rate constants of FAD release (k _b) and binding (k _-b) as well as the irreversible aggregation of the apo-enzyme (k _agg) were less sensitive to changes in temperature, their activation energy (E _a) being about 52 kJ mol^-1 in comparison with an E _a value of 185 kJ mol^-1 for k _a. The rate-determining step of TvDAO inactivation switched from FAD dissociation to unfolding at high temperatures. The model adequately described the effect of protein concentration on inactivation kinetics. Its predictions regarding the extent of FAD release and aggregation during thermal denaturation were confirmed by experiments. TvDAO is shown to contain two highly reactive cysteines per protein subunit whose modification with 5,5'-dithio-bis (2-nitrobenzoic acid) was accompanied by inactivation. Dithiothreitol (1 mmol L^-1) enhanced up to 10-fold the recovery of enzyme activity during ion exchange chromatography of technical-grade TvDAO. However, it did not stabilize TvDAO at all temperatures and protein concentrations, suggesting that deactivation of cysteines was not responsible for thermal denaturation.     

How well does cholesteryl hemisuccinate mimic cholesterol in saturated phospholipid bilayers?

Journal of Molecular Modeling - We studied the doping effects on the electronic and structural properties of graphene upon interaction with phenol. Calculations were performed within the periodic...     

Transgelin Silencing Induces Different Processes in Different Breast Cancer Cell Lines

Transgelin is a protein reported to be a marker of several cancers. However, previous studies have shown both up‐ and down‐regulation of transgelin in tumors when compared with non‐tumor tissues and the mechanisms whereby transgelin may affect the development of cancer remain largely unknown. Transgelin is especially abundant in smooth muscle cells and is associated with actin stress fibers. These contractile structures participate in cell motility, adhesion, and the maintenance of cell morphology. Here, the role of transgelin in breast cancer is focused on. Initially, the effects of transgelin on cell migration of the breast cancer cell lines, BT 549 and PMC 42, is studied. Interestingly, transgelin silencing increased the migration of PMC 42 cells, but decreased the migration of BT 549 cells. To clarify these contradictory results, the changes in protein abundances after transgelin silencing in these two cell lines are analyzed using quantitative proteomics. The results confirmed the role of transgelin in the migration of BT 549 cells and suggest the involvement of transgelin in apoptosis and small molecule biochemistry in PMC 42 cells. The context‐dependent function of transgelin reflects the different molecular backgrounds of these cell lines, which differ in karyotypes, mutation statuses, and proteome profiles.     

以黑丝羽乌骨鸡为供体制作家鸡嵌合体的研究

以黑丝羽乌骨鸡（BS）为供体,自来航鸡（WL）为受体,进行了BCs嵌合体制作技术研究。结果表明：（1）“黑羽”对“白羽”、“丝羽”对“片羽”为完全隐性,可以在供体与嵌合体测交中,后代是否出现这些特征作为种系嵌合体判断依据。（2）供体的其它表型,对受体属于完全或不完全显性,可以作为体细胞嵌合体判断依据。（3）通过改进嵌合体制作技术,嵌合体雏鸡的出壳率为40％（29／73）,其中据羽色判断的嵌合体率为18％（13／73）;以黑羽为依据选择体细胞嵌合体雏鸡,10只饲养至720d,其中60％（6／10）的嵌合体外观基本不变（其余的换羽后褪去黑羽）;嵌合体鸡与供体测交,以黑羽、灰羽和丝羽判断,8只嵌合体鸡的种系传递率分别为2．5％-71．4％、5．5％～14．3％以及1．7％～10．5％。首次利用BS鸡资源,建立了多表现型嵌合体模型,为家鸡嵌合体技术深入研究提供了方便的检测方法。     

Assessment of trends in predation pressure on insects across temperate forest microhabitats

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Estimation of the quantity of bacteria encapsulated in Lentikats Biocatalyst via phospholipid fatty acids content: a preliminary study

The content of phospholipid fatty acids (PLFA) was determined in samples of polyvinyl alcohol lenses (Lentikats Biocatalyst, LB) with encapsulated Paracoccus denitrificans withdrawn during long-term denitrification experiments. The total PLFA content correlated highly with specific denitrification activities of LB as well as biomass estimation based on image analyses of microscopic photos. The results confirmed the applicability of PLFA determination for estimation of the amount of living encapsulated microbial biomass during biotechnological applications.     

Large‐scale disturbance legacies and the climate sensitivity of primary Picea abies forests

Determining the drivers of shifting forest disturbance rates remains a pressing global change issue. Large‐scale forest dynamics are commonly assumed to be climate driven, but appropriately scaled disturbance histories are rarely available to assess how disturbance legacies alter subsequent disturbance rates and the climate sensitivity of disturbance. We compiled multiple tree ring‐based disturbance histories from primary Picea abies forest fragments distributed throughout five European landscapes spanning the Bohemian Forest and the Carpathian Mountains. The regional chronology includes 11,595 tree cores, with ring dates spanning the years 1750–2000, collected from 560 inventory plots in 37 stands distributed across a 1,000 km geographic gradient, amounting to the largest disturbance chronology yet constructed in Europe. Decadal disturbance rates varied significantly through time and declined after 1920, resulting in widespread increases in canopy tree age. Approximately 75% of current canopy area recruited prior to 1900. Long‐term disturbance patterns were compared to an historical drought reconstruction, and further linked to spatial variation in stand structure and contemporary disturbance patterns derived from LANDSAT imagery. Historically, decadal Palmer drought severity index minima corresponded to higher rates of canopy removal. The severity of contemporary disturbances increased with each stand's estimated time since last major disturbance, increased with mean diameter, and declined with increasing within‐stand structural variability. Reconstructed spatial patterns suggest that high small‐scale structural variability has historically acted to reduce large‐scale susceptibility and climate sensitivity of disturbance. Reduced disturbance rates since 1920, a potential legacy of high 19th century disturbance rates, have contributed to a recent region‐wide increase in disturbance susceptibility. Increasingly common high‐severity disturbances throughout primary Picea forests of Central Europe should be reinterpreted in light of both legacy effects (resulting in increased susceptibility) and climate change (resulting in increased exposure to extreme events).