Gegenseitige Beeinflussung von Roggen (Secale cereale L.) und Hanf (Cannabis sativa L.) in Wasserkulturen bei nicht ergänzter Nährung

Práce studuje vzájemný vztah mezi konopím (Cannabis sativa L.) a ?item (Secale cereale L.) ve vodní kultu?e p?i nedoplňované minerální vý?ivě. Po 18 dnech kultivace v ?ivném roztoku s³²P byly nalezeny pr?kazné rozdíly v sorpci fosforu a rozdíly v transpiraci mezi kontrolními rostlinami a ve směsi. Konopí kontrola vy?erpalo za 18 dn? 85,5% fosforu, konopí ve směsi 94%, ?ito kontrola 95,3% a ?ito ve směsi 106,7%, v?dy p?epo?teno na jednu rostlinu. R?st ovlivněn nebyl. Výsledky nelze vysvětlit pouhou konkurencí o ?iviny mezi zú?astněnými druhy, ale jen p?ítomností dal?ího faktoru.     

Studies in the taxonomy of the Polypores II

The following genera are redefined:Albatrellus S. F. Gray,Heterobasidion Bref.,Haploporus Bond. et Sing. ex Sing.,Fomitopsis P. Karst. andRigidoporus Murrill two new subgenera are described:Polyporus subgen.Dendropolyporus Pouz. (type:Polyporus umbellatus) andRigidoporus subgen.Neooxyporus Pouz. (type:Polyporus latemarginatus); the genusOxyporus (Bourd. etGalz.)Donk is classified as a subgenus of the genusRigidoporus,Murrill and the generaBjerkandera P. Karst. andLeptoporus quél. are classified as subgenera of the genusTyromyces P. Karst. The new subfamilyAlbatrelloideae Pouz. (genera:Albatrellus andGrifola) is described and 14 new specific combinations are made. The new genusIrpicodon Pouz. (type:Irpex pendulus) is proposed.     

Enzyme mediated hydrolysis of acetates

Summary The investigation of enzyme mediated hydrolysis of the respective cis- and trans-2-(4-methoxybenzyl)-1-cyclohexyl acetates has been provided using several lipases. A comparison of results obtained has been summarized in this paper.     

Expression of phosphorylated high molecular weight neurofilament protein (NF-H) and vimentin in human developing dorsal root ganglia and spinal cord

The expression of vimentin and the phosphorylated variant of high molecular weight neurofilament protein (NF-H) was studied in developing human fetal dorsal root ganglia and spinal cord. The technique used for examination of cryosections was double-label fluorescence with monoclonal antibodies. Both proteins were present in the nerve fibres inside the ganglia of 6- and 8-week-old embryos. During further development the expression of vimentin continued to increase in the satellite cells, but was found to be decreasing in the ganglion cells. Phosphorylated NF-H was found in the processes of ganglion cells, as well as in the perikarya at all developmental stages. In the spinal cord of 6- and 8-week-old embryos, phosphorylated NF-H protein was found in the longitudinal fibres of the marginal layer and in processes of the mantle zone; some of the fibres also contained vimentin. Later the co-expression of the two proteins ceased and vimentin was found only in glial and mesenchymal derivatives. Phosphorylated NF-H was located, at all developmental stages, in the axons of both white and grey matter, but not in the neuronal perikarya. The results indicate that phosphorylation of the NF-H in human dorsal root ganglia starts in the perikarya of the ganglion cells while in the ganglion cells of the spinal cord it takes place in the axons.     

Boron-regulated hypocotyl elongation is affected in Arabidopsis mutants with defects in light signalling pathways

We studied the effect of elevated boron (B) concentrations on the growth and development of Arabidopsis thaliana in vitro with respect to different light conditions. Two basic responses were observed. At high concentrations (above 5 mM) a clear toxicity effect of B on plant growth was apparent. Seedlings were short, stunted and pale. However at concentrations between 1 and 3 mM H₃BO₃, hypocotyl elongation was stimulated in all Arabidopsis ecotypes tested relative to plants grown at 0.1 mM H₃BO₃. The stimulation of hypocotyl elongation by elevated B was proportionally greater with increasing irradiance. We also showed that blue light (BL) and red light (RL) did not alter the sensitivity of Arabidopsis hypocotyls to boron, but, dependent on genotype, BL and RL increased or reduced capacity of boron-induced hypocotyl elongation. Analysis of photomorphogenic mutants indicated the existence of an interaction between boron and light signalling pathways during plant growth and development. This interaction was supported by the observation that the expression of the BOR1 gene in Arabidopsis hypocotyls was stimulated by BL and RL. Our results suggest that in etiolated or light-grown seedlings the stimulation of hypocotyl growth by boron can be mediated by cryptochromes and phytochromes.     

Structure analysis of montmorillonite intercalated with rhodamine B: modeling and experiment

The intercalation process and the structure of montmorillonite intercalated with [rhodamine B]+ cations have been investigated using molecular modeling (molecular mechanics and molecular dynamics simulations), X-ray powder diffraction and IR spectroscopy. The structure of the intercalate depends strongly on the concentration of rhodamine B in the intercalation solution. The presence of two phases in the intercalated structure was revealed by modeling and X-ray powder diffraction: (i) phase with basal spacing 18 A and with bilayer arrangement of guests and (ii) phase with average basal spacing 23 A and with monolayer arrangement of guests. In both phases the monomeric and dimeric arrangement can coexist in the interlayer space. Three types of dimers in the interlayer structure have been found by modeling: (i) H-dimer (head-to-head arrangement) present in the 18 A phase, (ii) sandwich type of the head-to-tail arrangement (present in the 23 A phase) and (iii) J-dimer (head-to-tail arrangement) present in the 23 A phase. Figure Montmorillonite intercalated with rhodamine B cations. On the left: phase 18 A, bilayer dimeric arrangement of guests (H-dimers). On the right: phase 23 A, monolayer arrangement of guests prepared using intercalation solution with a low concentration of rhodamine B     

Topography of genetic loci in the nuclei of cells of colorectal carcinoma and adjacent tissue of colonic epithelium

To determine the influence of increased gene expression and amplification in colorectal carcinoma on chromatin structure, the nuclear distances between pairs of bacterial artificial chromosome (BAC) clones with genomic separation from 800 to 29,000 kb were measured and compared between the tumor and parallel epithelial cells of six patients. The nuclear distances were measured between the loci in chromosomal bands 7p22.3–7p21.3; 7q35–7q36.3; 11p15.5–11p15.4; 20p13; 20p12.2; 20q11.21 and 20q12 where increased expression had been found in all types of colorectal carcinoma. The loci were visualized by three-dimensional fluorescence in situ hybridization using 22 BAC clones. Our results show that for short genomic separations, mean nuclear distance increases linearly with increased genomic separation. The results for some pairs of loci fell outside this linear slope, indicating the existence of different levels of chromatin folding. For the same genomic separations the nuclear distances were frequently shorter for tumor as compared with epithelial cells. Above the initial growing phase of the nuclear distances, a plateau phase was observed in both cell types where the increase in genomic separation was not accompanied by an increase in nuclear distance. The ratio of the mean nuclear distances between the corresponding loci in tumor and epithelium cells decreases with increasing amplification of loci. Our results further show that the large-scale chromatin folding might differ for specific regions of chromosomes and that it is basically preserved in tumor cells in spite of the amplification of many loci.Communicated by T. Hassold     

Separation procedures applicable to lignan analysis

Lignans are a class of secondary plant metabolites produced by oxidative dimerization of two phenylpropanoid units. They have been found in many plants of Oriental medicine. In consequence of recent knowledge it is held that lignans are responsible for the key pharmacological activities of these plants. This review surveys the chromatographic, electromigration and hyphenated methods so far applied for the separation of lignans in Oriental plants used in phytotherapy as well as for the analyses of these lignans and their metabolites in biological matrices and food samples. In addition, the sample clean-up procedures--solvent extractions and supercritical fluid extractions--are also included.