Altitudinal variability of stand structure and regeneration in the subalpine spruce forests of the Pol’ana biosphere reserve,Central Slovakia

The structure of natural subalpine spruce forest in the Zadná Pol’ana massif of the Western Carpathians was analysed. We focused on the variability of different aspects of stand structure, tree decay and regeneration processes in altitudinal gradient. We used systematic sampling, covering an area of 2 km², to detect even subtle changes in stand structure within one forest type over a range of less than 200 m in elevation. Mean stand density was 290 trees (>7 cm DBH) per hectare, average basal area was 41 m² ha⁻¹, and the volume accumulation in living trees amounted to 500 m³/ha⁻¹. Stand volume decreased by more than 50% between 1,260 and 1,434 m a.s.l. This means for an increase of altitude of 100 m that stand volume decreased by nearly 200 m³. Neither stand density nor basal area was related to elevation. Maximum tree height was strongly correlated to elevation, and it decreased on average by 6 m for each 100 m increment of altitude. No significant changes in the maximum spruce diameter were recorded in relation to the elevation gradient. Spatial distribution of trees was biased toward regularity at lower altitudes. Tree clustering increased with increasing altitude. The stock of coarse woody debris (CWD) decreased slightly along the altitudinal gradient, but changes were not significant. Density of spruce saplings and their number growing on CWD significantly increased across the elevation gradient. Despite the fact that the analysed forest tract was relatively large, highly variable in respect to environmental factors, and that stand volume, spatial structure, and tree height displayed strong variability along the elevation gradient, the diameter structure of stands and regeneration measures were uniform. Our results suggest that the recruitment of new trees in the Zadná Pol’ana subalpine spruce forest is not temporally continuous even at a scale of several square kilometres.     

A giant tree stand in the West Carpathians—An exception or a relic of formerly widespread mountain European forests?

In Europe, remnants of formerly widespread natural mixed forests are rare. We analyzed an exceptionally tall tree stand with a very high wood volume in Hron?okovský grúň reserve, covering 55.2 ha in Slovenské Rudohorie Mountains in central Slovakia (48°43′N and 19°35′E) between 730 and 1050 m a.s.l. We compared our data to other natural stands to see if the growing stock and tree height were higher in Hron?okovský grúň.     

Sea anemone genome reveals ancestral eumetazoan gene repertoire and genomic organization

Sea anemones are seemingly primitive animals that, along with corals, jellyfish, and hydras, constitute the oldest eumetazoan phylum, the Cnidaria. Here, we report a comparative analysis of the draft genome of an emerging cnidarian model, the starlet sea anemone Nematostella vectensis. The sea anemone genome is complex, with a gene repertoire, exon-intron structure, and large-scale gene linkage more similar to vertebrates than to flies or nematodes, implying that the genome of the eumetazoan ancestor was similarly complex. Nearly one-fifth of the inferred genes of the ancestor are eumetazoan novelties, which are enriched for animal functions like cell signaling, adhesion, and synaptic transmission. Analysis of diverse pathways suggests that these gene "inventions" along the lineage leading to animals were likely already well integrated with preexisting eukaryotic genes in the eumetazoan progenitor.     

Bioavailability of methionine hydroxy analog-free acid relative to DL-methionine in broilers

Three experiments were conducted to determine and validate the relative bioefficacy of the liquid form of hydroxy analog (liquid MHA‐FA) to that of DL‐methionine (Met) in male broilers. In experiments 1 and 2, 945 and 550 male broilers were fed either a Met‐deficient basal diet, or the basal diet supplemented with four and five equimolar levels of each Met source, respectively. In experiment 3, 1232 male broilers were fed either a Met‐deficient basal diet, or the basal diet with three levels (low, moderate, or high) of liquid MHA‐FA or DL‐Met at 65% of the liquid MHA‐FA level. Growth performance improved in all trials, regardless of the Met source, relative to those broilers fed the basal diet. In experiments 1 and 2, the bioefficacy estimates for liquid MHA‐FA relative to DL‐Met on a product basis were: 50% and 64% for weight gain, 51% and 59% for the feed conversion ratio, and 54% and 48% for breast‐meat yield, respectively. In experiment 3, there were no differences between the DL‐Met or liquid MHA‐FA treatments, and the broilers fed liquid MHA‐FA were 68% as efficient on a product basis as those fed DL‐methionine for weight gain. The results from these three trials indicate that the bioefficacy of liquid MHA‐FA relative to DL‐methionine is 57% on a product basis on average across all criteria tested.     

In vitro studies on the influence of dexamethasone and meloxicam on bovine WC1+ γδ T cells

In view of the lack of data on the effect of meloxicam (non-steroidal anti-inflammatory drug) on bovine γδ T cells (WC1⁺ cells) and very poorly recognized effects of dexamethasone (steroidal anti-inflammatory drug) on these cells, the purpose of the present study has been to determine the in vitro influence of these drugs on CD25^highWC1⁺, CD25^lowWC1⁺ and CD25^?WC1⁺ lymphocytes of the peripheral blood of cattle. Peripheral blood mononuclear cells were treated with the drugs in concentrations reflecting their plasma levels achieved in vivo at therapeutic doses (dexamethasone 10^?7 M; meloxicam 5 × 10^?6 M) and at ten-fold lower concentrations. It was found out that percentages and absolute counts of CD25^highWC1⁺ and CD25^lowWC1⁺ cells increased in the presence of dexamethasone, and this effect was at least partly attributable to lower mortality of these cells, whose apoptosis was depressed by exposure to dexamethasone. It seems certain that this effect was not a result of increased multiplication of CD25^highWC1⁺ and CD25^lowWC1⁺ cells because their proliferation was reduced in the presence of dexamethasone. Exposure to this drug caused a rapidly occurring and lasting depletion of CD25^?WC1⁺, which was at least partly due to their higher apoptosis. The results seem to suggest that impaired proliferation of these cells was responsible for a more profound expression of this disorder. Paradoxically, the percentage of cells producing IFN-γ, a proinflammatory cytokine, increased in the presence of dexamethasone, whereas the count of cells secreting the key anti-inflammatory and immunosuppressive cytokine, i.e. IL-10, declined. This effect was observed in all analyzed subpopulations of cells. Meloxicam did not interfere so drastically as dexamethasone with the functioning of WC1⁺ lymphocytes because it did not affect their apoptosis, proliferation, percentage or absolute count. With respect to the effect of meloxicam on counts of particular WC1⁺ lymphocyte subpopulations, it was only demonstrated that exposure to the drug was correlated with a transient and very weakly expressed decrease in the relative and absolute counts of CD25^highWC1⁺ and CD25^lowWC1⁺ cells, which was most probably a result of a temporary down-regulation of the expression of the CD25 molecule. In the presence of meloxicam, percentages of IFN-γ⁺CD25^?WC1⁺ cells as well as cells producing IL-10 declined, an effect observed in all analyzed cell populations. These results suggest that care should be taken when administering this medication to animals with bacterial or viral infections, and we should avoid giving it to patients suffering from allergic or autoimmune disorders.     

Black rice (Oryza sativa L. indica) pigmented fraction suppresses both reactive oxygen species and nitric oxide in chemical and biological model systems

Anthocyanins, present in fruits and vegetables as natural colorants, have been well characterized to possess bioactive properties. Anthocyanin components extracted from black rice (Oryza sativa L. indica) separated by gel filtration and identified using LC-MS were cyanidin 3-glucoside and peonidin 3-glucoside. A standardized extract of black rice pigmented fraction (BRE) containing known proportions of cyanidin 3-glucoside and peonidin 3-glucoside exhibited marked antioxidant activities and free radical scavenging capacities in a battery of in vitro model systems. Significant (p < 0.05) prevention of supercoiled DNA strand scission induced by reactive oxygen species (specifically, peroxyl radical and hydroxyl radicals) and suppression of the oxidative modification of human low-density lipoprotein was obtained with BRE. In addition, BRE reduced (p < 0.05) the formation of nitric oxide by suppressing inducible nitric oxide synthase expression in murine macrophage RAW264.7 cells, without introducing cell toxicity. The results of this study show that black rice contains anthocyanin pigments with notable antioxidant and anti-inflammatory properties for potential use in nutraceutical or functional food formulations.     

Antioxidative effect of quercetin and its equimolar mixtures with phenyltin compounds on liposome membranes

Our earlier studies have shown that the compounds diphenyltin dichloride (DPhT) and triphenyltin chloride (TPhT) in the presence of UVC radiation enhanced the degree of phosphatidylcholine liposome membrane oxidation (J. Agric. Food Chem. 2005, 53, 76-83). The prooxidative behavior of the compounds has now been confirmed with the electron paramagnetic resonance method, which proved the possibility that the studied compounds can exist in free radical forms. The present work investigates the possibility of the protective action of quercetin on phosphatidylcholine liposome membranes exposed to the prooxidative action of DPhT and TPhT induced by UV radiation (lambda = 253.7 nm). The concentrations of quercetin and its equimolar mixtures with DPhT and TPhT were determined (and compared with well-known antioxidants as standards-trolox and butylated hydroxytoluene, also in the presence of phenyltins) as those that induce 50% inhibition in oxidation of liposomes radiated with UV. They are 5.1 +/- 0.10, 2.9 +/- 0.12, and 1.9 +/- 0.08 microM (differences between the values are statistically significant), constituting the following sequence of antioxidative activity: quercetin:TPhT > quercetin:DPhT > quercetin. This relation is confirmed by the results on the antiradical ability of quercetin and its mixtures with DPhT and TPhT toward the free radical 1,1-diphenyl-2-pricrylhydrazil. Similar sequences obtained in both studies suggest a possible mechanism of the antiradical action of the mixtures as free radical scavengers. We suggested that (i) quercetin's ability, documented by spectrophotometric, infrared attenuated total reflectance spectroscopy, (1)H NMR, and molecular modeling methods, to form complexes with phenyltins indicates a possible way of protection against the peroxidation caused by the free radical forms of phenyltins and (ii) the differentiation in the action of the quercetin/TPhT and quercetin/DPhT associates (statisticaly significant) may result from a different localization in the liposome membrane, which is indicated by the results of the fluorimetric studies.     

Phase transitions, solubility, and crystallization kinetics of phytosterols and phytosterol-oil blends

The thermal properties, solubility characteristics, and crystallization kinetics of four commercial phytosterol preparations (soy and wood sterols and stanols) and their blends with corn oil were examined. Differential scanning calorimetry (DSC) revealed narrow melting peaks between 138 and 145 degrees C for all phytosterol samples, reversible on rescan. Broader and less symmetrical melting transitions at lower temperatures with increasing oil content were observed for two samples of phytosterol-oil admixtures. The estimated, from the solubility law, deltaH values (34.7 and 70.7 mJ/mg for wood sterols and stanols, respectively), were similar to the DSC experimental data. Fatty acid esters of soy stanols differing in the chain length of the acyl groups (C2-C12) exhibited suppression of the melting point and increase of the fusion enthalpy with increasing chain length of the acyl group; the propionate ester exhibited the highest melting point (Tm: 151 degrees C) among all stanol-fatty acid esters. Solubility of phytosterols in corn oil was low (2-3% w/w at 25 degrees C) and increased slightly with a temperature rise. Plant sterols appeared more soluble than stanols with higher critical concentrations at saturation. The induction time for recrystallization of sterol-oil liquid blends, as determined by spectrophotometry, depended on the supersaturation ratio. The calculated interfacial free energies between crystalline sediments and oil were smaller for sterol samples (3.80 and 3.85 mJ/m2) than stanol mixtures (5.95 and 6.07 mJ/m2), in accord with the higher solubility of the sterol crystals in corn oil. The XRD patterns and light microscopy revealed some differences in the characteristics among the native and recrystallized in oil phytosterol preparations.