This study is part of a general project to analyse the biological and ecological mechanisms that influence the invasion of Mediterranean sand dune ecosystems by alien plants. In this paper we analyse the morphological and functional traits of coastal dune wild species (natives and aliens) based mainly on information from the literature. The most common 130 wild species occurring on the recent (Holocenic) coastal dunes were included considering the invasive status of alien plants. A comparative analysis of functional groups was performed through ordination techniques (PCoA using the Gower index). This reveals four functional groups related to the most important plant communities in coastal vegetation zonation. Alien plants were found in all functional groups and no trait or set of traits was specifically related to them. This indicates that aliens show similar traits to those natives growing in different communities of the coastal dune zonation, from the small beach annuals to the evergreen taller shrubs of the Mediterranean macchia. When the invasive status of alien species was taken into account, however, some differences emerged: a) casual aliens were found in almost all groups but their traits were not interpreted as being due to any particular adaptive strategy; b) naturalised aliens were only found in the less fluctuating habitats of the inner coastal zones; c) invasive alien species were connected with two major plant strategies: annual invasive aliens (quick-to-mature low grasses and herbs) and perennial invasive aliens (taller and often strongly clonal).
A century ago, Alfred Nissle discovered that intentional intake of particular strains of Escherichia coli could treat patients suffering from infectious diseases. Since then, one of these strains became the most frequently used probiotic E. coli in research and was applied to a variety of human conditions. Here, properties of that E. coli Nissle 1917 strain are compared with other commercially available E. coli probiotic strains, with emphasis on their human applications. A literature search formed the basis of a summary of research findings reported for the probiotics Mutaflor, Symbioflor 2, and Colinfant. The closest relatives of the strains in these products are presented, and their genetic content, including the presence of virulence, genes is discussed. A similarity to pathogenic strains causing urinary tract infections is noticeable. Historic trends in research of probiotics treatment for particular human conditions are identified. The future of probiotic E. coli may lay in what Alfred Nissle originally discovered: to treat gastrointestinal infections, which nowadays are often caused by antibiotic-resistant pathogens.
Authors:V. Posevitz, C. Vizler, S. Benyhe, E. Duda, and Anna Borsodi
Psychological stress modulates the immune system through the hypothalamic-pituitary-adrenal axis, the sympatho-adrenomedullary axis and the opioid system. According to literature data, restraint stress increases the immune cell apoptosis, decreases the spleen and thymus cell content, the natural killer (NK) activity in the spleen, and it compromises the anti-tumor immune response in mice. We immobilized mice in two consecutive nights, and then determined the cell number, apoptosis, NK cell content, NK activity and the level of cytokine mRNAs (TNF-β, TNF-α, IL-4, IL-5, IL-1α, IFN-γ, IL-2, IL-6, IL-1β and IL-3) in the thymus and spleen. No consistent changes were detected in any of the immune parameters either in C57Bl/6 or in DBA/2 mice. Stressed or control B6 mice were injected with B16 melanoma cells immediately after the immobilization or one week later. No significant differences were found in the growth of primary tumors and lung metastases in stressed and control animals. Taken together, our mice, kept in a general-purpose non-SPF animal house, seemed to be refractory to the stress-induced immunomodulation. Our interpretation is that stress-induced immunomodulation can occur only in mice isolated from any background stressors, or rather natural stimuli, throughout their life.
In the present study, morphological and anatomical structures of cypsela – 12 Cirsium Miller (Carduoideae, Asteraceae) taxa belonging to two sections (sect. Cirsium and sect. Cephalonoplos) were investigated in detail with using stereomicroscope and light microscope. The taxa were evaluated comparatively in the aspect of carpological variations and their anatomies were presented in here for the first time. Morphological features including size, shape and colour of cypselae were examined. From anatomical observations, anatomical structures of pericarp, as well as the structure of testa were described. Cypselae colours differ from light brown to stramineous, sometimes with blackish striations. Their shapes change from oblong to oblanceolate, rarely obovate. The largest cypselae are present in C. echinus (1.59±0.03 mm × 4.68±0.07 mm) and the smallest ones are found in C. subinerme (1.20±0.02 mm × 2.97±0.05 mm). The pericarp is characterised by almost parenchymatous cells, while the testa is composed of lignified sclerenchymatous cell lines and crushed cells group. Secretory structure in testa bundle was evaluated. Results obtained from this study were compared with the present data in literature. Overall, morphological and anatomical characteristics of cypselae provide useful taxonomic markers in their classifications of the studied taxa of Cirsium but not distinctive for their sectional levels.
The importance of accurate species databases is debated in the recent literature of biodiversity assessment, considering that limited resources for conservation could be better allocated to assessment based on cost effective biodiversity features. I aimed to provide an understanding of sampling bias and provide practical advice to minimize bias either before or after data collection. I used 10×10 km
UTM grid data for 121 land snail species to account for geographic and taxonomic sampling bias in Hungary. Sampling intensity corrected for species richness varied significantly among regions, although regions were not good predictors of sampling intensity. Residuals were significantly autocorrelated in 15 km distance, indicating small scale heterogeneity in sampling intensity compared to species richness. Sampling coverage and intensity were higher close to human settlements and sampling intensity was higher within protected areas than outside. Commonness of species was positively associated with sampling intensity, while some rare species were over-represented in the records. Sampling intensity of microsnails (<3 mm) was significantly lower than that of the more detectable large species (>15 mm). Systematic effects of the collecting methods used in malacological research may be responsible for these differences. Understanding causes of sampling bias may help to reduce its effects in ecological, biogeographical and conservation biological applications, and help to guide future research.
Species diversity loss is expected to alter ecosystem function, but previous work has demonstrated inconsistent relationships between these two factors. Productivity is the most common measure of ecosystem function, but given the difficulty in measuring productivity, standing biomass or change in biomass are frequently used as proxy measures. A review of the recent ecosystem-function literature revealed that 93% of studies measure productivity as biomass, thereby assuming a strong positive relationship between these two variables. We tested this assumption by measuring biomass and productivity in seagrass beds in the Gulf of Mexico. We found that the relationship between standing biomass and productivity could be positive or negative, depending on site. Change in biomass over months inconsistently underestimated short-term productivity. The relationship between biomass and productivity may depend on plant age, successional stage, or site-specific rates of tissue loss to herbivory, senescence, or disturbance. Our results suggest that if biomass continues to be used as a measure of productivity without justification, highly productive communities that typically show little change in biomass, such as healthy climax communities, will not be interpreted as such. The conflicting results of previous studies investigating the relationship between diversity and productivity may be due to differences in the inherently variable relationship between biomass and productivity at different sites and scales.
One of the greatest concerns in community ecology is to find how species composition patterns are related to different environmental and spatial conditions. This approach is especially interesting when applied to high diversity heterogeneous forests such as the Brazilian Atlantic Rainforest sensu lato. The present study aims to verify the existence of indicator species in four southern Atlantic Rainforest formations and identify relationships among distributions of tree species with environmental and spatial variables. For that, tree species density data of 21 phytosociological surveys were collected from the literature. The data were analyzed using indicator species and partial canonical redundancy analysis (partial RDA). Sandy coastal formation contained the greatest number of indicator species (17), followed by Atlantic rainforest (10), cloud forest (4) and Araucaria forest (3). The partial RDA analysis explained 22% of total data variation, of which 11% was assigned to the environment, 5% to space, 6% to spatial component of environmental influence, and 78% remained undetermined. The forest formations present different sets of indicator species suggesting replacement of species along the forest formations. The largest and significant fraction of variation in the composition and abundance of tree species explained by environmental variables reflects the heterogeneity and complexity of habitats throughout the region of Atlantic Forest. The low spatial influence and the environmental results indicate a pattern of structured communities due to different requirements of niches by species (niche theory).
Multivariate analysis of variance, based on randomization (permutation) test, has become an important tool for ecological data analyses. However, a comprehensive evaluation of the accuracy and power of available methods is still lacking. This is a thorough examination of randomization tests for multivariate group mean differences. With simulated data, the accuracy and power of randomization tests were evaluated using different test statistics in one-factor multivariate analysis of variance (MANOVA). The evaluations span a wide spectrum of data types, including specified and unspecified (field data) distributional properties, correlation structures, homogeneous to very heterogeneous variances, and balanced an unbalanced group sizes. The choice of test statistic strongly affected the results. Sums of squares between groups (Qb) computed on Euclidean distances (Qb-EUD) gave better accuracy. Qb on Bray-Curtis, Manhattan or Chord distances, the multiresponse permutation procedure (MRPP) and the sum of univariate ANOVA F produced severely inflated type I errors under increasing variance heterogeneity among groups, a common scenario in ecological data. Despite pervasive claims in the ecological literature, the evidence thus suggests caution when using test statistics other than Qb-EUD.
An intense debate is underway on the different approaches to measuring the importance of neighbour interaction. Both the ecological meaning and the statistical suitability of one of the most popular indices have been seriously questioned, but no simpler and practical alternative tools have been proposed up to now. This paper proposes a novel approach based on the use of new normalized indices which scale the effects of neighbours and environment to the maximum target-plant potential. Two indices related to environmental suitability and size-asymmetry are suggested as tools to stratify data in homogeneous subsets before analysis, and an index of normalized neighbour effect (Nn) is proposed to integrate the measuring of neighbour importance and intensity. When tested on literature data, Nn index proves to be very highly correlated to the most currently used importance index. At the same time, it is moderately but significantly correlated to the intensity index. Yet, an accurate reanalysis of three published datasets proves that several detected trends are predictable on the basis of the inherent properties of the used indices. This is inextricably linked to the use of the same phytometers at different productivity levels. Thus, a glimpse is proposed towards the opportunity to use groups of equivalent competitors, each one working at a different point of the gradient, but all in a comparable range of environmental suitability and potential size-asymmetry relative to neighbours. Once defined these equivalence conditions, the normalized Nn metric is suited to measure how the relative weight of neighbour impact changes along the productivity gradient.