A novel, neural potential of non-hematopoietic human umbilical cord blood stem cells

From the time of discovery that among the cord blood mononuclear cell population there are cells capable of changing their fate towards the neural lineage and producing functional neurons and macroglial cells, our attempts have been focused on the understanding of the underlying mechanism of this transition. We have deciphered the first steps of neural stem/progenitor gene induction in aggregating culture of cord blood mononuclear cells, their rapid phenotypic conversion under the influence of neuromorphogenic signals due to mitogen activation and their ability to expand and develop a prototypic, long-living line with neural stem cell properties. Evidence has accumulated that human umbilical cord-derived and neurally committed cells, due to their capacity for self-renewal, multilineage differentiation, plasticity and ability for long-lasting growth in vitro, provide unique material for the cell therapy of a wide spectrum of neurological diseases. The putative regenerating potential of these cord blood-derived neural stem/progenitor cells was evaluated after transplantation in experimental models of brain injury. In spite of initial promising data, the results indicate an urgent need to improve available animal model protocols in order to increase immuno-tolerance toward transplanted human cells.     

Somatostatin-like immunoreactivity in the amygdala of the pig

The distribution and morphology of neurons containing somatostatin (SOM) was investigated in the amygdala (CA) of the pig. The SOM-immunoreactive (SOM-IR) cell bodies and fibres were present in all subdivisions of the porcine CA, however, their number and density varied depending on the nucleus studied. The highest density of SOM-positive somata was observed in the layer III of the cortical nuclei, in the anterior (magnocellular) part of the basomedial nucleus and in the caudal (large-celled) part of the lateral nucleus. Moderate to high numbers of SOM-IR cells were also observed in the medial and basolateral nuclei. Many labeled neurons were also consistently observed in the lateral part of the central nucleus. In the remaining CA regions, the density of SOM-positive cell bodies varied from moderate to low. In any CA region studied SOM-IR neurons formed heterogeneous population consisting of small, rounded or slightly elongated cell bodies, with a few poorly branched smooth dendrites. In general, morphological features of these cells clearly resembled the non-pyramidal Golgi type II interneurons. The routine double-labeling studies with antisera directed against SOM and neuropeptide Y (NPY) demonstrated that a large number of SOM-IR cell bodies and fibers in all studied CA areas contained simultaneously NPY. In contrast, co-localization of SOM and cholecystokinin (CCK) or SOM and vasoactive intestinal polypeptide (VIP) was never seen in cell bodies and fibres in any of nuclei studied. In conclusion, SOM-IR neurons of the porcine amygdala form large and heterogeneous subpopulation of, most probably, interneurons that often contain additionally NPY. On the other hand, CCK- and/or VIP-IR neurons belonged to another, discrete subpopulations of porcine CA neurons.     

Effect of urbanization on centipede (Chilopoda) diversity in the Wielkopolska-Kujawy Lowlands of western Poland

Over fifty years of research data from various sources were compiled and analyzed in order to determine the effect of urbanization on centipede diversity in the Wielkopolska-Kujawy Lowlands of western Poland. Urbanization has had a significant effect on species composition and community structures. However, it has not reduced overall species richness and diversity in the centipede fauna. The centipede fauna from built-up areas was found to be rich and varied. The habitats with the highest levels of species richness were the city of Poznań and the beech forests in the surrounding region.     

Magnitude and direction of DNA bending induced by screw-axis orientation: influence of sequence, mismatches and abasic sites

DNA-bending flexibility is central for its many biological functions. A new bending restraining method for use in molecular mechanics calculations and molecular dynamics simulations was developed. It is based on an average screw rotation axis definition for DNA segments and allows inducing continuous and smooth bending deformations of a DNA oligonucleotide. In addition to controlling the magnitude of induced bending it is also possible to control the bending direction so that the calculation of a complete (2-dimensional) directional DNA-bending map is now possible. The method was applied to several DNA oligonucleotides including A(adenine)-tract containing sequences known to form stable bent structures and to DNA containing mismatches or an abasic site. In case of G:A and C:C mismatches a greater variety of conformations bent in various directions compared to regular B-DNA was found. For comparison, a molecular dynamics implementation of the approach was also applied to calculate the free energy change associated with bending of A-tract containing DNA, including deformations significantly beyond the optimal curvature. Good agreement with available experimental data was obtained offering an atomic level explanation for stable bending of A-tract containing DNA molecules. The DNA-bending persistence length estimated from the explicit solvent simulations is also in good agreement with experiment whereas the adiabatic mapping calculations with a GB solvent model predict a bending rigidity roughly two times larger.     

Why boron?

It is now more than 80 years since boron was convincingly demonstrated to be essential for normal growth of higher plants. However, its biochemical role is not well understood at the moment. Several recent reviews propose that B is implicated in three main processes: keeping cell wall structure, maintaining membrane function, and supporting metabolic activities. However, in the absence of conclusive evidence, the primary role of boron in plants remains elusive. Besides plants, growth of specific bacteria, such as heterocystous cyanobacteria and the recently reported actinomycetes of the genus Frankia, requires B, particularly for the stability of the envelopes that control the access of the nitrogenase-poisoning oxygen when they grow under N₂-fixing conditions. Likewise, a role for B for animal embryogenesis and other developmental processes is being established. Finally, a new feature of the role of boron comes from signaling mechanisms for communication among bacteria and among legumes and rhizobia leading to N₂-fixing symbiosis, and it is possible that new roles for B, based on its special chemistry and its interaction with Ca would appear in the world of signal transduction pathways. In conclusion, the diversity of roles played by B might indicate that either the micronutrient is involved in numerous processes or that its deficiency has a pleiotropic effect. The arising question is why such an element? Since all of the roles clearly established for B are related to its capacity to form diester bridges between cis-hydroxyl-containing molecules, we propose that the main reason for B essentiality is the stabilization of molecules with cis-diol groups turning them effective, irrespectively of their function.     

Abrupt Changes in Bosmina (Cladocera,Crustacea) Assemblages During the History of the Ostrowite Lake (Northern Poland)

During the 10000-year history of the Ostrowite Lake, there have been several episodes of change in dominance amongst species of the genus Bosmina. The dominants were alternately B.longirostris and Eubosmina spp. Amongst the subgenus Eubosmina, two species prevailed in different periods:Bosmina coregoni and Bosmina reflexa. The first species, Bosmina coregoni, is characterized by long antennae and short carapace mucrones, while the second one, Bosmina reflexa, by short antennae and very long mucrones. Bosmina reflexa was dominant at the beginning of the lake's history (Preboreal, 10000--9000 BP) and during the early Subboreal Period (5000–3500 BP). Only a small number of remains of Bosmina longispina(Eubosmina spp.) were present along the entire profile. Such strong changes in the domination of Bosmina species were observed for the first time in the sediments of Polish lakes. A similar transition from one species to another has been described in a few German lakes and was linked to climate changes. However, the changes in the Ostrowite Lake do not correlate with climate changes, but most probably, with changes in the lake's trophic level. This is suggested by the simultaneous increase of Bosmina reflexa and a good indicator of eutrophy, Bosmina longirostris.     

Structure of the O-polysaccharide and classification of Proteus mirabilis strain G1 in Proteus serogroup O3.

The O-chain polysaccharide of the lipopolysaccharide (LPS) of a previously nonclassified strain of Proteus mirabilis termed G1 was studied by sugar analysis and 1H and 13C NMR spectroscopy, including 2D COSY, TOCSY, rotating-frame NOE (ROESY), H-detected 1H,13C HMQC, and heteronuclear multiple-bond correlation (HMBC) experiments. The following structure of the polysaccharide was established: [carbohydrate structure: see text] where D-GalA6(L-Lys) stands for N(alpha)-(D-galacturonoyl)-L-lysine. The structure of the O-polysaccharide of P. mirabilis G1 is similar, but not identical, to that of P. mirabilis S1959 and OXK belonging to serogroup O3. Immunochemical studies with P. mirabilis G1 and S1959 anti-(O-polysaccharide) sera revealed close LPS-based serological relatedness of P. mirabilis G1 and S1959, and therefore it was suggested to classify P. mirabilis G1 in serogroup O3 as a subgroup. P. mirabilis G1 and S1959 anti-(O-polysaccharide) sera also cross-reacted with LPS of P. mirabilis strains from two other serogroups containing D-GalA6(L-Lys) in the O-polysaccharide or in the core region.     

Optimized somatic embryogenesis in Pinus strobus L.

Summary Somatic embryogenesis (SE) initiation in Pinus strobus was optimized by the manipulation of plant growth regulator (PGR) concentrations in the culture medium. Modified Litvay medium (MLV) of Litvay et al. (1985) supplemented with lower than routinely used PGR concentration increased initiation of established embryogenic cultures from approximately 20 to 53%. The original developmental stage of zygotic embryos had a pronounced effect on the SE response. The optimum stage was the pre- to shortly post-cleavage stage. A substantial genetic influence on initiation of SE was indicated by a significant variance component due to families. Genotype X collection date and genotype X media interactions had large effects on initiation of SE. The PGR levels in the culture medium prior to maturation had a significant effect on subsequent production of mature somatic embryos. Embryogenic tissue initiated and proliferated on medium with a low level of PGR consistently produced a high number of somatic embryos, indicating that optimized initiation protocol also enhanced somatic embryo production. Somatic embryos of 93 embryogenic lines (representing five families) that were initiated on media with different PGR concentrations were converted to plants at an overall frequency of 76%, and grown in the greenhouse. With these improved protocols, application of P. strobus SE in commercial clonal forestry is feasible as an alternative to traditional breeding and reforestation.     

Modeling the formation of root apices

The formation of new root apices from small groups of cells with different cellular patterns has been simulated using an existing model based on growth tensors. To generate an apex, a steady growth field was used. The pattern of cells evolved to approach the steady state. Two extreme types of progressions have been obtained : one leading to an apex with a single or a few apical cells, and the other to an apex with a quiescent centre. The change of structure while applying a steady growth tensor indicates that development may involve a succession of discrete growth tensors.