Effect of proximity to ancient deciduous woodland on restoration of the field layer vegetation in a pine plantation

The influence of dominant tree species. soil conditions and distance ärom an adjacent ancient ouk-liernbeam woodland upon the floristic composition. species richness and spatial distributions of species in a pine wood planted on dry rendzina soil were studied in southern Poland. It was found that. in spite of a 52-yr long succession. the cover and composition of species in the pine wood were significantly different from that in the adjacent ancient woodland. Canonical correspondence analysis (CCA) and stepwise regression analyses showed that the distance to the ancient woodland had a significant influence on species distributions in the recent wood. The numbers of species from the Querco-Fagerea class. vegetatively reproducing species and myrrnochores decreased with this distance. whereas the numbers of tree species in the shrub and field layers and anemochores increased. The light intensity had a positive effect on the numbers of species in the shrub layer. non-woodland species and anemochores. The number of woodland species increased considerably with the cover of quickly decomposing litter and with thickness of the humus layer. The migration rate of many woodland species. calculated on occurrence of the farthest individuals was very' slow. varying from 0J8 m yr' to 0.38 m yr'. These results indicate that the availability of micro-sites suitable for seed germination and plant development determined the successful colonization of the recent wood to an extent comparable with the seed dispersal.     

The effects of the environmental antiandrogen vinclozolin on the induction of granulosa cell apoptosis during follicular atresia in pigs

The aim of this study was to investigate whether the androgens testosterone and dihydrotestosterone (DHT) and the antiandrogenic fungicide vinclozolin (Vnz) exert proapoptotic effects on porcine granulosa cells (GCs), and to examine the roles of these compounds in follicular atresia. Granulosa cells isolated from pig follicles were cultured for 24 hours, and then exposed to 0.1 μM testosterone, 0.1 μM DHT, 14 μM Vnz, or the equivalent concentrations of testosterone and Vnz or DHT and Vnz for a further 24 hours. Apoptosis and necrosis of the GCs were determined via Hoechst staining and flow cytometry analyses of annexin V-stained cells. Whole porcine follicles were also exposed to the same compounds and combinations of compounds for 24 hours. The sections were stained with hematoxylin and eosin for morphologic assessments, and a Terminal deoxynucleotidyl Transferase Biotyn-dUTP Nick-End Labeling (TUNEL) assay was performed to determine the number of apoptotic cells. The progesterone and estradiol concentrations secreted into the culture media by isolated GCs and follicles were also measured. Exposure to the androgens resulted in an increased number of apoptotic GCs both in vitro and in the organotypic model. Vinclozolin exposure increased and decreased the number of necrotic and apoptotic GCs, respectively. Furthermore, compared with control follicles, those exposed to testosterone, DHT, or Vnz displayed enhanced atresia, and coadministration of Vnz attenuated the promotive effect of these androgens on atresia. Estradiol secretion was stimulated by the combination of testosterone and Vnz, whereas exposure to Vnz alone reduced it. Progesterone production declined after the combined addition of androgens and the antiandrogen. In summary, Vnz caused massive necrosis of GCs in vitro and induced apoptosis of GCs in whole follicles. The androgens testosterone and DHT enhanced these effects. The results presented here suggest that selective destruction of porcine follicles is a serious consequence of exposure to Vnz, and may lead to premature ovarian failure in affected animals.     

Possibilities and limitations of seed production of Catharanthus roseus (L.) G. Don under Polish climatic conditions

The studies were carried out at Radzików, Central Poland in the years 1982–1991, using a progeny of an Indian population. It was proved that Catharanthus roseus may be grown in Poland under field conditions as an annual crop, using plants previously raised in glass or plastic houses. However, the culture of C. roseus in the greenhouse resulted in a higher yield of herb and particularly in a better setting of fruits and seeds than under field conditions. The yield of seeds obtained under cover was several times higher than in the field. Growing of plants under cover may be justified, as greenhouses usually are not utilised in the summertime. Consequent mass selection conducted during successive seasons has lead to obtaining the lines better adapted to the conditions of a cool climate and hence more productive. Improvement of generative traits, resulting from selection, was more pronounced than improvement of the vegetative indices. The ‘yellow silique’ has been recognised as an optimal stage for harvest, as at this stage siliques could be easily separated from the stems, whereas the risk of seed shedding was still minimal. Germinability of seeds obtained from siliques harvested at this stage was high and uniform.     

In search of female sterility causes in the tetraploid and pentaploid cytotype of Pilosella brzovecensis (Asteraceae)

Within the agamic Pilosella complex, apomixis (asexual reproduction through seed) involves apospory, parthenogenesis, and autonomous endosperm development. Observations of reproductive biology in P. brzovecensis throughout four growing seasons in the garden have shown that both tetraploid and pentaploid plants of this species do not produce viable seeds and reproduce exclusively vegetatively by underground stolons. The reasons for the seed development failure were unknown, therefore our research focused on the analysis of reproductive events in the ovules of this taxon. We found that apospory was initiated in the ovules of both cytotypes. Multiple aposporous initial (AI) cells differentiated in close proximity to the megaspore mother cell (MMC) and suppressed megasporogenesis at the stage of early prophase I. However, none of the AI cells was able to further develop into a multi-nucleate aposporous embryo sac (AES) due to the inhibition of mitotic divisions. It was unusual that callose was accumulated in the walls of AI cells and its synthesis was most likely associated with a response to the dysfunction of these cells. Callose is regarded as the isolating factor and its surprising deposition in the ovules of P. brzovecensis may signal disruption of reproductive processes that cause premature termination of the aposporous development pathway and ultimately lead to ovule sterility. The results of our embryological analysis may be the basis for undertaking advanced molecular studies aimed at fully understanding of the causes of female sterility in P. brzovecensis.

     

Synthesis and Mass Spectrometry Analysis of Mimosine-Containing Peptides

Non-proteinogenic amino acids are widely explored group of compounds due to their chemical properties and great potential of application in the combinatorial chemistry, medicinal investigation etc. Therefore the synthetic methods of their incorporation to the peptide chain are required. l-Mimosine, (S)-α-amino-β-(3-hydoxy-4-oxo-1,4-dihydropyridin-1-yl)-propanoic acid), is a plant amino acid, known to induce apoptosis in human pancreatic cancer xenografts. Here we present our investigations on the synthesis of mimosine-containing peptide and their ESI-MS/MS analysis. We successfully applied Fmoc-protected mimosine a with a free hydroxy ketone group for efficient peptide synthesis in the presence of HATU as a coupling reagent without the formation of side products. Additionally the tandem mass spectrometry analysis revealed the characteristic loss of the heterocyclic ring from mimosine residue side chain. The described method allows insertion of mimosine residue at any endo-position within a peptide sequence. The obtained results may be useful in the synthesis and mass spectrometry analysis of various mimosine-containing peptides.