Numerical analysis of morphology of natural hybrids between Carex hostiana and the members of Carex flava agg. (Cyperaceae)

Uni‐variate and multi‐variate statistical methods, based on data taken from dried specimens, were used to determine the morphological variance of Carex hostiana 3 Carex flava agg. hybrids and to establish their parents among members of the C. flava complex. The following hybrids were found: C. demissa 3 hostiana [C. 3 fulva], C. hostiana 3 lepidocarpa [C. ×leutzii] and C. flava 3 hostiana [C. 3 xanthocarpa]. The least variable traits, namely beak length, utricle length, ratio of beak length to the overall utricle length, female spike width, and width of the lowest bract, proved to be the most useful in delimiting the hybrids. Carex flava 3 hostiana specimens usually have long utricles and beaks, wide male and female spikes, as well as wide bracts and leaf blades. Carex hostiana 3 lepidocarpa specimens are characterized by relatively short beaks (with low ratio of beak length to the overall utricle length) and narrow bracts. Common features of C. demissa 3 hostiana specimens, on the other hand, are male spikes with long peduncles, usually longly parted female spikes and a long beak compared to the overall utricle length.     

EPR study and structural aspects of ferredoxins obtained from Thiobacillus ferrooxidans

A comparison of iron-sulfur proteins obtained from Thiobacillus ferrooxidans was carried out. The microorganisms were grown on iron(II)- or sulfur-containing nutrients. In both cases different, broad elctron paramagnetic resonance (EPR) lines, originating from an iron(III) compound, were detected. Additional EPR lines of tetrahedral iron(III) and free radicals were observed. The UV spectra of these compounds also differ. Received: 15 July 1998 / Received revision: 8 October 1998 / Accepted: 16 October 1998     

The synthesis of a new class of oxytocin antagonists.

The synthesis of a new class of oxytocin antagonists, with significantly modified C-terminal part, is described. The chemistry of the Mitsunobu reaction was applied to obtain the key derivatives. In spite of the extensive modifications of previously described compound F792, the peptides retain biological activity as oxytocin antagonists.     

Analysis of tomato gene promoters activated in syncytia induced in tomato and potato hairy roots by Globodera rostochiensis

The potato cyst nematode (Globodera rostochiensis) induces feeding sites (syncytia) in tomato and potato roots. In a previous study, 135 tomato genes up-regulated during G. rostochiensis migration and syncytium development were identified. Five genes (CYP97A29, DFR, FLS, NIK and PMEI) were chosen for further study to examine their roles in plant–nematode interactions. The promoters of these genes were isolated and potential cis regulatory elements in their sequences were characterized using bioinformatics tools. Promoter fusions with the β-glucuronidase gene were constructed and introduced into tomato and potato genomes via transformation with Agrobacterium rhizogenes to produce hairy roots. The analysed promoters displayed different activity patterns in nematode-infected and uninfected transgenic hairy roots.     

Shoals ofDreissena polymorpha as bio-processor of seston

Mussels ofD. polymorpha were collected from mesotrophic lake Partęczyny in which it occurs in form of narrow but very dense shoal. Having transported them to the laboratory live specimens were sorted with respect to size and placed in lake water on artificial substrata made with plexi plates. During the night most of mussels reattached to substrate with byssus threads. The plates covered with mussels were transported to shallow, eutrophic lake Druzno in whichD. polymorpha has not been present in recent years. A set of plates and separate plates were exposed in lake water to which a fine fraction of sediment was added. The resulting concentration of suspension was slightly higher than those found during intensive sediment resuspension. It was observed that during first 10–30 minutes of exposure to suspension mussels kept their valves closed, but after this time they were able to continue filtration. The obtained results showed that the relatively high concentration of sediment added to lake seston did not affect clearance capacity of suspension inD. polymorpha and even enhanced it.