Eco-coenotic conditions and structure of Trollius europaeus L. populations in an extrazonal habitat complex (Transylvanian Carpathian foothills)

To estimate the importance of community structure and environmental factors for maintenance and in situ conservation of populations of European Globeflower (Trollius europaeus subsp. europaeus) in four sites (one within a natural reserve) in a low elevation but cool valley of the Transylvanian Carpathian foothills, an inventory of all globeflower individuals was performed and floristic relevés were recorded in different community types (meadow, fen and scrub). As a surrogate for habitat conditions, we used plant species indicator values for light, moisture and nitrogen. Globeflower density is highest in mesic habitats, the ecological optimum estimated (about 6 on Ellenberg's scale) being slightly lower than that indicated for Central Europe (7). The juvenile:fertile plants ratio (J:F) declines with increasing soil moisture. Larger flower production in hygrophilous communities does not result in a higher proportion of juveniles or J:F ratio. Despite the presumed strong competition determined by high species richness in some host communities, the most dynamic population (large proportion of juveniles) was found in mesophilous, mown meadows. A clumped distribution of fertile plants under the open scrub canopy seems to be responsible for the significantly larger number of flowers per individual observed, as compared with the relative amount of flowers produced in the adjacent sward. Irrespective of host community, the juveniles display an aggregated distribution with respect to fertile plants, which is probably related to short-distance dispersal of seeds. Our results reveal the importance of host community species richness and soil moisture for the target population stage structure and reproductive investment.     

Sensing based on assessment of non-monotonous effect determined by target analyte: Case study on pore-forming compounds

A new and exciting biosensing avenue based on assessment of the non-monotonous, concentration dependent effect of pore formation is discussed. A novel kinetic model is advanced to relate surface plasmon resonance (SPR) data with actual concentrations of interacting partners. Lipid modified L1 sensor chip provide the accessible platform for SPR exploration of peptide–membrane interaction, with POPC and melittin as model systems. We show that quantitative assessment of the interaction between an antimicrobial peptide and lipid modified sensors is capable to provide both sensing avenues and detailed mechanistic insights into effects of pore-forming compounds. The proposed model combined with appropriate design of the experimental protocol adds a new depth to the classic SPR investigation of peptide–lipid interaction offering a quantitative platform for detection, improved understanding of the manifold facets of the interaction and for supporting the controlled design of novel antimicrobial compounds. This biosensing approach can be applied to an entire set of pore-forming compounds including antimicrobial peptides and exo-toxins.     

Loss of spermatogonia and wide-spread DNA methylation defects in newborn male mice deficient in DNMT3L

Background  

Formation of haploid spermatozoa capable of fertilization requires proper programming of epigenetic information. Exactly how DNMT3L (DNA methyltransferase 3-Like), a postulated regulator of DNA methyltransferase activity, contributes to DNA methylation pattern acquisition during gametogenesis remains unclear. Here we report on the role of DNMT3L in male germ cell development.     

Structural analysis of some soluble elastins by means of FT‐IR and 2D IR correlation spectroscopy

Fourier transform infrared (FT‐IR) spectroscopy combined with 2D correlation spectroscopy has been used to offer some information about stability and structure of some soluble elastins. Temperature has been chosen as the perturbation to monitor the infrared behavior of various soluble elastins, namely, α‐elastin p, α‐elastin, and k‐elastin. In the 3800–2700 cm^?1 region, the H‐containing groups were analyzed. The bonded hydroxyls are found to decrease prior to the NH‐related hydrogen bonds and also to the conformational reorganization of hydrocarbon chains. The transition temperatures were evaluated and they were found to agree with those obtained from DSC data. The FTIR spectra and their 2nd derivatives denote that α‐ elastins exhibited amide‐I, ‐II and ‐III bands at 1656, 1539 and 1236 cm^?1, respectively, while in k‐elastin these bands were found at 1652 cm^?1 for amide I, 1540 cm^?1 for amide II and 1248 cm^?1 for amide III. The macroscopic IR finger‐print method, which combines: general IR spectra, secondary derivative spectra, and 2D‐IR correlation spectra, is useful to discriminate different elastins. Thus using the differences of the position and intensity of the bands from “fingerprint region” of studied elastins, which include the peaks assigned to C?O, C? C groups from α‐helix, β‐turn, and the peaks assigned to the amide groups, it is possible to identify and discriminate elastins from each others. Furthermore, the pattern of 2D‐IR correlation spectra under thermal perturbation, allow their direct identification and discrimination. © 2010 Wiley Periodicals, Inc. Biopolymers 93: 1072–1084, 2010. This article was originally published online as an accepted preprint. The “Published Online” date corresponds to the preprint version. You can request a copy of the preprint by emailing the Biopolymers editorial office at biopolymers@wiley.com     

Mesophication in temperate Europe: A dendrochronological reconstruction of tree succession and fires in a mixed deciduous stand in Białowieża Forest

1. The shift from shade‐intolerant species to shade‐tolerant mesophytic species in deciduous and mixed forests of the temperate zone is well described in studies from North America. This process has been termed mesophication and it has been linked to changes in fire regime. Fire suppression results in the cessation of establishment of heliophytic, fire‐dependent tree species such as oak (Quercus) and pine (Pinus). Due to the scarcity of old‐growth forests in Europe, data on long‐term compositional changes in mixed forests are very limited, as is the number of studies exploring whether fire played a role in shaping the dynamics.
2. The aim of this study was to reconstruct tree succession in a 43‐ha natural mixed deciduous forest stand in Bia?owie?a Forest (BF), Poland using dendrochronological methods. In addition, the presence of aboveground fire legacies (charred and fire‐scarred deadwood) enabled the fire history reconstruction.
3. Dendrochronological data revealed tree establishment (Quercus) back to the end of the 1500s and fires back to 1659. Under a regime of frequent fires until the end of the 18th century, only oak and pine regenerated, sporadically. A shift in the fire regime in the first half of the 19th century triggered oak and pine cohort regeneration, then gradually spruce (Picea) encroached. Under an increasingly dense canopy and less flammable conditions, regeneration of shade‐tolerant Carpinus, Tilia, and Acer began simultaneously with the cessation of oak and pine recruitment.
4. Synthesis. The study reports the first evidence of mesophication in temperate Europe and proves that fire was involved in shaping the long‐term dynamics of mixed deciduous forest ecosystems. Our data suggest that fire exclusion promoted a gradual recruitment of fire‐sensitive, shade‐tolerant species that inhibited the regeneration of oak and pine in BF.