Leaving uncut refuges during meadow harvesting increases the functional diversity of Orthoptera

In the past, insect species richness was high in Central European seminatural grasslands, which were characterized by low‐intensity land use. Currently, however, the hay in most of these grasslands is mechanically harvested, which negatively impacts insect biodiversity. One way to reduce this negative effect is to leave unmown patches as refuges. In the current research we evaluated the short‐term effects of leaving an unmown patch on the taxonomic and functional diversity of the Orthoptera assemblage in a meadow. We found that orthopteran species richness and abundance were significantly reduced by mowing, whether or not a patch was left uncut. In contrast, functional evenness, indicating distribution of species abundances in a niche space, was reduced by mowing only if the plot lacked an uncut refuge. Functional richness, indicating the amount of niche space occupied by species, was elevated if the plot had an uncut refuge. Larger species were negatively affected by mowing, while habitat specialists, mobile species and soil‐ovipositing species benefitted from it. We infer that the presence of an uncut patch increased the diversity of habitats available to orthopterans and maintained even distribution of species among niche space. In summary, leaving an unmown refuge in grasslands could increase the functional diversity of orthopterans, even if it does not preserve taxonomic diversity.     

Transmembrane adaptor protein WBP1L regulates CXCR4 signalling and murine haematopoiesis

WW domain binding protein 1‐like (WBP1L), also known as outcome predictor of acute leukaemia 1 (OPAL1), is a transmembrane adaptor protein, expression of which correlates with ETV6‐RUNX1 (t(12;21)(p13;q22)) translocation and favourable prognosis in childhood leukaemia. It has a broad expression pattern in haematopoietic and in non‐haematopoietic cells. However, its physiological function has been unknown. Here, we show that WBP1L negatively regulates signalling through a critical chemokine receptor CXCR4 in multiple leucocyte subsets and cell lines. We also show that WBP1L interacts with NEDD4‐family ubiquitin ligases and regulates CXCR4 ubiquitination and expression. Moreover, analysis of Wbp1l‐deficient mice revealed alterations in B cell development and enhanced efficiency of bone marrow cell transplantation. Collectively, our data show that WBP1L is a novel regulator of CXCR4 signalling and haematopoiesis.     

Regulation of growth,nutritive, phytochemical and antioxidant potential of cultivated <Emphasis Type="Italic">Drimiopsis maculata</Emphasis> in response to biostimulant (vermicompost leachate,VCL) application

The effect of vermicompost leachate (VCL, low-cost biostimulant) on the growth, elemental (macro and micro-nutrients) and phytochemical content as well as the antioxidant potential of Drimiopsis maculata was evaluated. Three dilutions (1:5; 1:10 and 1:20) of VCL were tested and the cultivation lasted for 3 months. In addition to the recorded growth parameters, dried and ground plant materials (leaves and bulbs) were evaluated for nutrients, phenolic acids and antioxidant capacity. Vermicompost leachate application enhanced the growth of D. maculata, particularly, the leaves (VCL 1:10) and bulbs (VCL 1:20) which were significantly bigger than the controls. Apart from the concentration of phosphorus which was significantly lower in the leaves of VCL (1:20)-treated plants, the quantity of all four macro-nutrients analysed were similar with and without VCL. Similar observations were also demonstrated in the majority of quantified micro-nutrients in D. maculata. Relative to the control, VCL-treated plants had higher concentrations of the 10 phenolic acids quantified in the leaves. However, the majority of the quantified phenolic acids were not significantly enhanced in bulbs. Antioxidant activity of D. maculata extracts was generally higher in leaves than in the bulbs. The leaf extract from VCL (1:10 and 1:20)-treated plants exhibited lower oxygen radical absorbance capacity (ORAC) when compared to the control. However, bulbs from VCL (1:5) treatment had significantly higher ORAC than the control. From a conservational perspective, the current findings provided insight on viable approaches useful for mitigating challenges associated with over-harvesting of highly utilized but slow-growing plant species.     

A new insight into solid-state conformation of macrolide antibiotics

Quantitative analysis of the molecular conformations of the 14-membered macrolide antibiotics erythromycin A and B, clarithromycin, and roxithromycin in the solid state was performed. While the erythronolide macrocycle adopts a very similar folded-out conformation in all the macrolides studied, the proximity of the monosaccharide moieties, L-cladinose and D-desosamine, to each other is demonstrated to be the distinctive feature of their molecular conformations, based on atom-atom interaction energy analysis. More surprisingly, the common features in the relative orientation of the monosaccharide moieties (in terms of non-bonded atom-atom interactions) were revealed between the 14- and 15-membered (azithromycin) macrolide antibiotics. Herein we report on the details of the spatial arrangement of the monosaccharide moieties in these structurally related drug molecules and their influence on the biopharmaceutical properties of erythromycin derivatives.     

Alien plant invasions in tropical and sub-tropical savannas: patterns,processes and prospects

Biological invasions affect virtually all ecosystems on earth, but the degree to which different regions and biomes are invaded, and the quality of information from different regions, varies greatly. A large body of literature exists on the invasion of savannas in the Neotropics and northern Australia where invasive plants, especially African grasses, have had major impacts. Less has been published on plant invasions in African savannas, except for those in South Africa. Negative impacts due to plant invasions in African savannas appear to be less severe than in other regions at present. As savannas cover about 60% of the continent, with tens of millions of people relying on the services they provide, it is timely to assess the current status of invasions as a threat to these ecosystems. We reviewed the literature, contrasting the African situation with that of Neotropical and Australian savannas. A number of drivers and explanatory factors of plant invasions in savannas have been described, mostly from the Neotropics and Australia. These include herbivore presence, residence time, intentional introductions for pasture improvements, fire regimes, the physiology of the introduced species, and anthropogenic disturbance. After comparing these drivers across the three regions, we suggest that the lower extent of alien plant invasions in African savannas is largely attributable to: (1) significantly lower rates of intentional plant introductions and widespread plantings (until recently); (2) the role of large mammalian herbivores in these ecosystems; (3) historical and biogeographical issues relating to the regions of origin of introduced species; and (4) the adaptation of African systems to fire. We discuss how changing conditions in the three regions are likely to affect plant invasions in the future.     

Evaluating the stability of the classification of community data

We propose a method for a posteriori evaluation of classification stability which compares the classification of sites in the original data set (a matrix of species by sites) with classifications of subsets of its sites created by without‐replacement bootstrap resampling. Site assignments to clusters of the original classification and to clusters of the classification of each subset are compared using Goodman‐Kruskal's lambda index. Many resampled subsets are classified and the mean of lambda values calculated for the classifications of these subsets is used as an estimation of classification stability. Furthermore, the mean of the lambda values based on different resampled subsets, calculated for each site of the data set separately, can be used as a measure of the influence of particular sites on classification stability. This method was tested on several artificial data sets classified by commonly used clustering methods and on a real data set of forest vegetation plots. Its strength lies in the ability to distinguish classifications which reflect robust patterns of community differentiation from unstable classifications of more continuous patterns. In addition, it can identify sites within each cluster which have a transitional species composition with respect to other clusters.     

Determination of 8-iso-prostaglandin F(2alpha) in exhaled breath condensate using combination of immunoseparation and LC-ESI-MS/MS

Rapid and precise method for the determination of 8-iso-prostaglandin F(2alpha), an essential marker of the oxidative stress, in exhaled breath condensate (EBC) was developed. The protocol consisted of stable isotope dilution, immunoseparation combined with selective and sensitive LC-ESI-MS/MS operated in multiple reaction monitoring (MRM) mode. The imprecision of the developed method was below 8.8%, the parameter of mean inaccuracy was determined as <9.6% (0-250pg of 8-iso-prostaglandin F(2alpha)/ml EBC). The limit of detection (LOD) was 1 pg/ml EBC and limit of quantification (LOQ) 5 pg/ml EBC. A significant difference in 8-iso-prostaglandin F(2alpha) content between the group of asbestosis patients and healthy volunteers was found.     

Habitat requirements, short-term population dynamics and coexistence of native and invasive Impatiens species: a field study

The genus Impatiens (Balsaminaceae) includes three widespread species in the Czech Republic, central Europe: the native I. noli-tangere, and two invasive species, I. parviflora and I. glandulifera, differing in the dynamics of invasion. They all occur in similar habitats and share basic life-history characteristics, which make them a suitable model for studying species traits associated with invasiveness. In this study we investigated differences in habitat requirements of these Impatiens species, their coexistence and short-term population dynamics in the field. We established 84 1 × 1 m permanent plots in five localities where all three species co-occurred. In each plot vascular plant species were determined, their cover estimated and all individuals of Impatiens species counted. Site characteristics including tree canopy cover, soil moisture, nitrogen and carbon content, and slope were measured directly. Nutrients, light, humidity and soil reaction were estimated using Ellenberg indicator values. The presence of I. noli-tangere was strongly correlated with high soil moisture, that of I. parviflora with high tree canopy cover and low soil moisture. Impatiens glandulifera exhibited a unimodal response to tree canopy cover, avoiding both very shaded and fully open sites. The current-year abundances of all species were negatively related to those of congeneric species. These results suggest that the coexistence of Impatiens species in the same habitat is due to microsite differentiation. Further spread of I. glandulifera to new habitats, and reduction of the native I. noli-tangere niche, can be expected in areas where the latter species co-occurs with competitively strong invasive congeners.     

Silicon promotes cytokinin biosynthesis and delays senescence in Arabidopsis and Sorghum

Silicate minerals are dominant soil components. Thus, plant roots are constantly exposed to silicic acid. High silicon intake, enabled by root silicon transporters, correlates with increased tolerance to many biotic and abiotic stresses. However, the underlying protection mechanisms are largely unknown. Here, we tested the hypothesis that silicon interacts with the plant hormones, and specifically, that silicic acid intake increases cytokinin biosynthesis. The reaction of sorghum (Sorghum bicolor) and Arabidopsis plants, modified to absorb high versus low amounts of silicon, to dark‐induced senescence was monitored, by quantifying expression levels of genes along the senescence pathway and measuring tissue cytokinin levels. In both species, detached leaves with high silicon content senesced more slowly than leaves that were not exposed to silicic acid. Expression levels of genes along the senescence pathway suggested increased cytokinin biosynthesis with silicon exposure. Mass spectrometry measurements of cytokinin suggested a positive correlation between silicon exposure and active cytokinin concentrations. Our results indicate a similar reaction to silicon treatment in distantly related plants, proposing a general function of silicon as a stress reliever, acting via increased cytokinin biosynthesis.