Recovery of bioactive compounds from Pinus pinaster wood by consecutive extraction stages

Pinus pinaster wood samples, obtained at different positions of three healthy trees, were subjected to two sequential extractions using an Accelerated Solvent Extraction instrument. The first extraction was carried out with hexane (to remove lipophilic extractives) and the second one with acetone/water (95:5 v/v) to recover bioactive phenolic compounds, the target compounds of this study. The extracted fractions were assayed for total yield and composition. The extracts contained a spectrum of phenolic compounds (simple phenolics, phenolic stilbenes, flavonoids and lignans) and non-phenolic components (juvabiones, resin and fatty acids, steryl esters and triglycerides). The fractionation effects achieved by consecutive extractions and the recovery of bioactive phenolics are discussed.     

Stimulated activity of the soil nitrifying community accelerates community adaptation to Zn stress

Field data have shown that soil nitrifying communities gradually adapt to zinc (Zn) after a single contamination event with reported adaptation times exceeding 1 year. It was hypothesized that this relatively slow adaptation relates to the restricted microbial diversity and low growth rate of the soil nitrifying community. This hypothesis was tested experimentally by recording adaptation rates under varying nitrification activities (assumed to affect growth rates) and by monitoring shifts in community composition. Soils were spiked at various Zn concentrations (0-4000 mg Zn kg⁻¹) and two NH₄⁺-N doses (N1, N2) were applied to stimulate growth. A control series receiving no extra NH₄⁺-N was also included. Soils were incubated in pots under field conditions with free drainage. The pore water Zn concentration at which nitrification was halved (EC50, mg Zn l⁻¹) did not change significantly during 12 months in the control series (without NH₄⁺-N applications), although nitrification recovered after 12 months at the highest Zn dose only. The EC50 after 12 months incubation increased by more than a factor 10 with increasing NH₄⁺-N dose (p < 0.05) illustrating that increased activity accelerates adaptation to Zn. Zinc tolerance tests confirmed the role of Zn exposure, time and NH₄⁺-N dose on adaptation. Zinc tolerance development was ascribed to the AOB community since the AOB/AOA ratio (AOB = ammonia oxidizing bacteria; AOA = ammonia oxidizing archaea) increased from 0.4 in the control to 1.4 in the most tolerant community. Moreover, the AOB amoA DGGE profile changed during Zn adaptation whereas the AOA amoA DGGE profile remained unaffected. These data confirm the slow but pronounced adaptation of nitrifiers to Zn contamination. We showed that adaptation to Zn was accelerated at higher activity and was associated with a shift in soil AOB community that gradually dominated the nitrifying community.     

Isolation and characterization of bone marrow-derived equine mesenchymal stem cells

OBJECTIVE: To isolate and characterize bone marrow-derived equine mesenchymal stem cells (MSCs) for possible future therapeutic applications in horses. SAMPLE POPULATION: Equine MSCs were isolated from bone marrow aspirates obtained from the sternum of 30 donor horses. PROCEDURES: Cells were cultured in medium (alpha-minimum essential medium) with a fetal calf serum content of 20%. Equine MSC features were analyzed to determine selfrenewing and differentiation capacity. For potential therapeutic applications, the migratory potential of equine MSCs was determined. An adenoviral vector was used to determine the transduction rate of equine MSCs. RESULTS: Equine MSCs can be culture-expanded. Equine MSCs undergo cryopreservation in liquid nitrogen without altering morphologic characteristics. Furthermore, equine MSCs maintain their ability to proliferate and differentiate after thawing. Immunocytochemically, the expression of the stem cell marker CD90 can be detected on equine MSCs. The multilineage differentiation potential of equine MSCs was revealed by their ability to undergo adipogenic, osteogenic, and chondrogenic differentiation. CONCLUSIONS AND CLINICAL RELEVANCE: Our data indicate that bone marrow-derived stromal cells of horses can be characterized as MSCs. Equine MSCs have a high transduction rate and migratory potential and adapt to scaffold material in culture. As an autologous cell population, equine MSCs can be regarded as a promising cell population for tissue engineering in lesions of the musculoskeletal system in horses.     

Relationship between somaclonal variation and type of culture in cucumber

Highly inbred B line of cucumber was used to compare the effect of four types of in vitro culture on somaclonal variation. The plants were regenerated from the following types of culture: twelve- and eighteen-month-old liquid culture of meristematic clumps (LMC₁₂₍₁₈₎), ten-month-old embryogenic cytokinin-dependent suspension (CDS), eighteen-month-old embryogenic cytokinin-dependent suspension in medium with modified NH⁺ ₄/NO₃ ^- ratio (CDS 1.7), twelve-month-old embryogenic auxin-dependent suspension (ADS), thirty six-month-old embryogenic auxin-dependent suspension in medium with modified NH⁺ ₄/NO₃ ^- ratio (ADS 1.7) and recurrent leaf callus regeneration (RLC) – repeated 5 times. The differences in the incidence of the following properties were observed: the ploidy of R₀ plants, the segregation of new morphological traits in R₁ and the germination ability of R₁ seeds. R₁ families with the segregation of new phenotypes were most numerous in CDS (62.5%) and LMC₁₈ (57.9%), next in CDS1.7 (35.7%), while the smallest number was found in LMC₁₂ (11.1%) and RLC (3.4%).Tetraploid and mixoploid plants occurred in ADS1.7 and ADS (100%) whereas CDS and RLC were observed to contain only tetraploids, respectively 33.3% and 55.2%. There were no changes of ploidy after LMC₁₂, LMC₁₈ and CDS1.7. Among new phenotypes there were such that have not been described so far in cucumber: ginkgolike leaf (gll), yellow-green chlorophyll mutants (y-gc), serrate margin of corolla in male and female flowers (smc). This revised version was published online in August 2006 with corrections to the Cover Date.     

Long-term impact of fertilization on activity and composition of bacterial communities and metabolic guilds in agricultural soil

To explore long-term impact of organic and inorganic fertilizers on microbial communities, we targeted both the total bacterial community and the autotrophic ammonia oxidizing bacteria (AOB) in soil from six treatments at an experimental field site established in 1956: cattle manure, sewage sludge, Ca(NO₃)₂, (NH₄)₂SO₄, unfertilized and unfertilized without crops. All plots, except the bare fallows, were cropped with maize. Effects on activity were assessed by measuring the basal respiration and substrate induced respiration (SIR) rates, and the potential activity of the AOB. To determine the bacterial community composition, 16S rRNA genes were used to fingerprint total soil communities by terminal restriction fragment length polymorphism analysis and AOB communities by denaturing gradient gel electrophoresis. The fertilization regimes had clear effects on both activity and composition of the soil communities. Basal respiration and r, which was kinetically derived as the exponentially growing fraction of the SIR-response, correlated well with the soil organic C content (r=0.93 and 0.66, respectively). Soil pH ranged from 3.97 to 6.26 in the treatments and was found to be an important factor influencing all microbial activities. pH correlated negatively with the ratio between basal respiration and SIR (r=0.90), indicating a decreased efficiency of heterotrophic microorganisms to convert organic carbon into microbial biomass in the most acid soils with pH 3.97 and 4.68 ((NH₄)₂SO₄ and sewage sludge fertilized plots, respectively). The lowest SIR and ammonia oxidation rates were also found in these treatments. In addition, these treatments exhibited individually different community fingerprints, showing that pH affected the composition of AOB and total bacterial communities. The manure fertilized plots harbored the most diverse AOB community and the pattern was linked to a high potential ammonia oxidation activity. Thus, the AOB community composition appeared to be more strongly linked to the activity than the total bacterial communities were, likely explained by physiological differences in the populations present.     

Urbanization and homogenization - Comparing the floras of urban and rural areas in Germany

The process of urbanization has resulted in an expansion of alien plant species and declines of native species, in particular already rare species. These processes may cause a greater similarity between different urban regions, i.e. biotic homogenization. We explored the relationship between urban regions and homogenization for plant species in Germany using (i) all plant species, (ii) only native species, (iii) all alien species and only those introduced (iv) before or (v) after 1500, respectively. We used the database FLORKART for species distribution on a 6 min latitude × 10 min longitude (ca. 130 km²) scale. We calculated mean similarities for the 60 “most urbanized” cells. We then resampled 60 randomly drawn “less urbanized” cells and 60 “rural” cells and compared these results to the “most urbanized” cells taking distance effects into account. Urbanization does not have an overall effect on homogenization of all species, but native species as well as pre-1500 alien plant assemblages show effects of homogenization while post-1500 alien plant assemblages show the opposite effect. On a regional scale, urbanization is not unequivocally related to homogenization. This might be different when extending the analysed range across several bioclimatic regions. Specific urban habitats, or what remains of them, require special protection and management if the trend towards homogenization is to be avoided.     

Embolism induced by winter drought may be critical for the survival of <Emphasis Type="Italic">Pinus sylvestris</Emphasis> L. near its southern distribution limit

Introduction   

Scots pine populations in the SE “Sistema Ibérico” range suffered a severe defoliation in the S face of the crown in isolated trees of thinned stands. This process was detected at the end of the winter 2001–2002.     

Review of ground-based methods to measure the distribution of biomass in forest canopies

? Context

Ecological research and an effective forest management need accurate information on the structure of the forest canopy to understand the biochemical, physiological and biogeochemical processes within a forest.

? Research question

This paper reviews the currently available instruments for measuring the distribution of biomass within forest canopies. We compare the most well-established approaches and present the different measurable parameters. A special focus lies on the resolution of the obtained data.

? Results

It was found that only 3D laser scanners offer data with the resolution required by ecologists, private landholders, the forest industry and the public to detect trends in tree growth patterns and canopy interactions in all three spatial dimensions. But data validation, data analysis and parameter extraction are still under development, and the price of the instrument is quite high.

? Conclusion

Research should focus on the parameter extraction from terrestrial laser scanner data as this could allow the calculation of functional attributes for different sections of a canopy on a high spatial resolution. It could also help ecologists characterize the structure of forest stands in a quick and precise way.