Absorption of the flavin dimers

The electronic absorption spectra of the flavomononucleotide (FMN) in aqueous solution and in glycerine-water solution with change of the dye concentration have been measured. The FMN dimer absorption spectrum, monomer absorption spectrum, dimerization constant K and molar fraction of the monomer were calculated. It was found that FMN dimerization constants in aqueous solution were K_a = 118.0 l/mol and in glycerine K_g = 20.5 l/mol. In the region of the monomer absorption band two dimer absorption bands appear, in accordance with the Kasha molecular exciton theory.     

Preparation and preliminary biological screening of cholic acid-juvenoid conjugates

Steroidal compounds have been utilized as carriers and for modification of physico-chemical properties of model biologically active secondary alcohols - juvenoids. Juvenoids are juvenile hormone analogues - environmentally safe insecticides, possessing significant biological activity towards different arthropods groups in focus on insect pest species. Structure modification of juvenoids plays important role to control the rate of liberation and decomposition of juvenoid in digestive system and can also play important role in the mode of action towards selected insect. This study presents an approach to the synthesis of steroidal monomers and dimers carrying one and two molecules of a juvenoid in their structures. The prepared compounds were tested for their inhibition activity on reproduction of the blowfly Neobellieria (Sarcophaga) bullata. These steroid-juvenoid conjugates showed promising possibilities in synthesis of new unique biochemical insecticides. Preliminary biological test results of prepared compounds are presented.     

Impact of the alien plant Impatiens glandulifera on species diversity of invaded vegetation in the northern foothills of the Tatra Mountains,Central Europe

Plant Ecology - The impact of exotic annual Impatiens glandulifera on invaded European vegetation is ambiguous; there are studies reporting considerable negative as well as weak or even no impact...     

XX/XY System of Sex Determination in the Geophilomorph Centipede Strigamia maritima

We show that the geophilomorph centipede Strigamia maritima possesses an XX/XY system of sex chromosomes, with males being the heterogametic sex. This is, to our knowledge, the first report of sex chromosomes in any geophilomorph centipede. Using the recently assembled Strigamia genome sequence, we identified a set of scaffolds differentially represented in male and female DNA sequence. Using quantitative real-time PCR, we confirmed that three candidate X chromosome-derived scaffolds are present at approximately twice the copy number in females as in males. Furthermore, we confirmed that six candidate Y chromosome-derived scaffolds contain male-specific sequences. Finally, using this molecular information, we designed an X chromosome-specific DNA probe and performed fluorescent in situ hybridization against mitotic and meiotic chromosome spreads to identify the Strigamia XY sex-chromosome pair cytologically. We found that the X and Y chromosomes are recognizably different in size during the early pachytene stage of meiosis, and exhibit incomplete and delayed pairing.     

A multi-criteria decision-making model for classifying wood products with respect to their impact on environment

Background, aim and scope  

Although life cycle assessment is frequently used in scientific studies of product comparison, many practitioners are looking for improvements in the normalisation, grouping and weighting of life cycle inventory results. Local conditions, which are well known to local experts, are very important to these steps. The goal of this work was to develop a computer-based decision support system for classifying wood products according to their influence on the environment in their whole life cycle. The model specifically addresses local conditions in the Republic of Slovenia and was developed by Slovenian experts.     

An Automated System for Monitoring and Regulating the pH of Bicarbonate Buffers

The bicarbonate buffer is considered as the most biorelevant buffer system for the simulation of intestinal conditions. However, its use in dissolution testing of solid oral dosage forms is very limited. The reason for this is the thermodynamic instability of the solution containing hydrogen carbonate ions and carbonic acid. The spontaneous loss of carbon dioxide (CO₂) from the solution results in an uncontrolled increase of the pH. In order to maintain the pH on the desired level, either a CO₂ loss must be completely avoided or the escaped CO₂ has to be replaced by quantitative substitution, i.e. feeding the solution with the respective amount of gas, which re-acidifies the buffer after dissociation. The present work aimed at the development of a device enabling an automatic pH monitoring and regulation of hydrogen carbonate buffers during dissolution tests.     

The Oscillopolarographic Behaviour of Deoxyribonucleic Acids Isolated from Bacillus Subtilis and Bacillus brevis

Summary The behaviour of DNA from several strains ofB. subtilis andB. brevis on the dropping mercury electrode in a medium of ammonium formate was studied. Native DNA yields in this medium on the oscillogram dE/dt againstE an anodic indentation for which the residues of deoxyguanylic acid are responsible.B. subtilis DNA produces a substantially smaller indentation thanB. brevis DNA does. It was found that the difference is not conditioned by impurities in the DNA samples, nor by the presence of denatured DNA. The difference in the depth of the indentation produced byB. subtilis andB. brevis DNAs almost disappears after denaturation of these DNAs or in an ammonium formate medium of higher concentration. The assumption was advanced that the different oscillopolarographic behaviour of DNAs obtained fromB. subtilis andB. brevis is connected with the different primary structure of these DNAs.     

Salix bifax undS. Mariana

Ohne Zusammenfassung