Changes in the seasonal rhythm of two forest communities during secondary succession

Changes in the seasonal rhythm of two plant phytocoenoses in a submountain beech forest during secondary succession were studied. Investigations were done on four monitoring plots with different stand density over the period of four successive years. The rhythm of the associations Dentario bulbiferae-Fagetum and Carici pilosae-Fagetum reflects the course of succession processes running six years after the human impact (cutting) in the ecosystem. Results of the phenological observations of the understorey species with the focus on the changes in flowering and colour spectrum allowed to make the comparisons between both associations in connection with different phyto-climatic conditions and in dependence on time. The most conspicuous changes in the seasonal rhythm and structure of the examined associations were found in conditions of the former clear-cut, currently in succession phase. A clear decrease (56%) in number of taxons with the dominance > 1% in one association towards the end of the 4-year study period was detected here. Simultaneously, a decrease in the number of flowering species was observed, while the relative rate of species being in the vegetative stage increased considerably (from 6 to 67%) over the growing season. The course of flowering of both of the associations missed discernible trends and peaks as well as colour spectra were partially changed during four monitored successive years on the formerly unstocked area.     

Mouth cavity base defect treated with biosynthetic graft

The use of in vitro prepared biosynthetic grafts can considerably improve the patient’s quality of life. This work reports on the use of an autologous graft prepared from a patient’s preputial cells cultivated on biodegradable polymeric membrane. Coladerm membrane is based on the chemically modified polyelectrolyte complex of atelocollagen and hyaluronan. The graft was used to cover a defect in the mouth cavity base and tongue after reconstruction surgery performed at this site in the past. The presented clinical case showed that the autologous biosynthetic graft prepared from foreskin cells can be successfully used for covering of medium-size defects in mouth cavity base resulting in the regeneration of target mouth structures with significant improvement of patient’s quality of life.     

Hyperparasites of the genus shape Ampelomyces on powdery mildew fungi in Serbia

From 1982 to 1996, in Serbia, 229 species of plants infected with powdery mildew were collected. Seventy-five species had hyperparasites of the genus Ampelomyces. Distribution analysis showed that hyperparasitism was greatest on plants from the families Asteraceae, Apiaceae and Fabaceae. Ampelomyces was not found on the family Poaceae. It was reported for the first time on the families Amygdalaceae, Cornaceae, Grossulariaceae, Plantaginaceae, Rhamnaceae and other 37 plant species. Hyperparasites of the genus Ampelomyces were found on 33 different species of fungi that are causal agents of powdery mildews. They are reported for the first time on nine species. Pycnidial size varied in the range 45–106 × 25.5–40.5 μm and conidia from 4.5–10.5 × 2.5–4.8 μm. This revised version was published online in June 2006 with corrections to the Cover Date.     

Structural insights into the dynamics and function of the C-terminus of the E. coli RNA chaperone Hfq

The hexameric Escherichia coli RNA chaperone Hfq (Hfq(Ec)) is involved in riboregulation of target mRNAs by small trans-encoded RNAs. Hfq proteins of different bacteria comprise an evolutionarily conserved core, whereas the C-terminus is variable in length. Although the structure of the conserved core has been elucidated for several Hfq proteins, no structural information has yet been obtained for the C-terminus. Using bioinformatics, nuclear magnetic resonance spectroscopy, synchrotron radiation circular dichroism (SRCD) spectroscopy and small angle X-ray scattering we provide for the first time insights into the conformation and dynamic properties of the C-terminal extension of Hfq(Ec). These studies indicate that the C-termini are flexible and extend laterally away from the hexameric core, displaying in this way features typical of intrinsically disordered proteins that facilitate intermolecular interactions. We identified a minimal, intrinsically disordered region of the C-terminus supporting the interactions with longer RNA fragments. This minimal region together with rest of the C-terminal extension provides a flexible moiety capable of tethering long and structurally diverse RNA molecules. Furthermore, SRCD spectroscopy supported the hypothesis that RNA fragments exceeding a certain length interact with the C-termini of Hfq(Ec).