Field-scale transplantation experiment to investigate structures of soil bacterial communities at pioneering sites

Studies on the effect of environmental conditions on plants and microorganisms are a central issue in ecology, and they require an adequate experimental setup. A strategy often applied in geobotanical studies is based on the reciprocal transplantation of plant species at different sites. We adopted a similar approach as a field-based tool to investigate the relationships of soil bacterial communities with the environment. Soil samples from two different (calcareous and siliceous) unvegetated glacier forefields were reciprocally transplanted and incubated for 15 months between 2009 and 2010. Controls containing local soils were included. The sites were characterized over time in terms of geographical (bedrock, exposition, sunlight, temperature, and precipitation) and physicochemical (texture, water content, soluble and nutrients) features. The incubating local ("home") and transplanted ("away") soils were monitored for changes in extractable nutrients and in the bacterial community structure, defined through terminal restriction fragment length polymorphism (T-RFLP) of the 16S rRNA gene. Concentrations of soluble ions in most samples were more significantly affected by seasons than by the transplantation. For example, NO(3)(-) showed a seasonal pattern, increasing from 1 to 3 μg NO(3)(-) (g soil dry weight)(-1) after the melting of snow but decreasing to <1 μg NO(3)(-) (g soil dry weight)(-1) in autumn. Seasons, and in particular strong precipitation events occurring in the summer of 2010 (200 to 300 mm of rain monthly), were also related to changes of bacterial community structures. Our results show the suitability of this approach to compare responses of bacterial communities to different environmental conditions directly in the field.     

Identification of DNA sequence variation in Campylobacter jejuni strains associated with the Guillain-Barré syndrome by high-throughput AFLP analysis

Background  

Campylobacter jejuni is the predominant cause of antecedent infection in post-infectious neuropathies such as the Guillain-Barré (GBS) and Miller Fisher syndromes (MFS). GBS and MFS are probably induced by molecular mimicry between human gangliosides and bacterial lipo-oligosaccharides (LOS). This study describes a new C. jejuni-specific high-throughput AFLP (htAFLP) approach for detection and identification of DNA polymorphism, in general, and of putative GBS/MFS-markers, in particular.     

Harnessing biosynthesis and quantitative NMR for late stage functionalization of lead molecules: Application to the M1 positive allosteric modulator (PAM) program

A facile method for late stage diversification of lead molecules for the M1 PAM program using biosynthesis is described. Liver microsomes from several species are screened to identify a high turnover system. Subsequent incubations using less than 1?mg of substrate generate nanomole quantities of drug metabolites that are purified, characterized by microcryoprobe NMR spectroscopy, and quantified to known concentrations to enable rapid biology testing. The late-stage diversification of lead compounds provides rapid SAR feedback to the medicinal chemistry design cycle.     

The vacuolar-tubular continuum in living trichomes of chickpea (Cicer arietinum) provides a rapid means of solute delivery from base to tip

Summary A vacuolar continuum exists from base to tip in the secretory trichomes of chickpea (Cicer arietinum). This continuum is seen in living trichomes which have been labeled with Lucifer yellow CH and examined with confocal microscopy. It encompasses the large vacuole of the lower stalk cell, the vacuoles and tubules of the central stalk cell, the thin tubules of the upper stalk cell, and the tubules and vacuoles of the secretory head cells. The vacuolar-tubular system is structurally distinct within each cell, forming a gradient of large vacuoles in the lower stalk cell, thick tubules in the central stalk cell, and thin anastamozing tubules in the upper stalk cell. This membrane system appears to be continuous between trichome cells, as thin tubules emanate from plasmodesmata between stalk cells and between the upper stalk and lower head cell. In the upper stalk cell, the thin tubules of this continuum are streaming up and down the long axis of the cell at 0.67 m/s. The larger vacuolar-tubular system in the central and lower stalk cells is also slowly moving, with apparent peristalsis occurring in the central cell. The vacuolar-tubular system of the secretory head cells is completely labeled with Lucifer yellow when the dye has only partly diffused up the long walls of the trichome, indicating that the streaming tubular system delivers solute through the stalk cells to the secretory head cells faster than diffusion through the trichome walls. In the lower head cells, tubules emanate from the plasmodesmata connecting to the upper stalk cell, and these tubules are continuous with the head cell vacuoles. In addition, another layer of thin tubules forms along the edges of the secretory head cells, at the site of exocytotic secretion. We propose that the continuous vacuolar-tubular system in these trichomes functions to rapidly deliver solute from the base of the trichome to the secretory head cells. This system provides a pathway for the transport of secretory material.Dedicated to Prof. Dr. Dr. h.c. Eberhard Schnepf on the occasion of his retirement     

The circadecadal rhythm of oscillation of umbilical cord blood parameters correlates with geomagnetic activity – An analysis of long-term measurements (1999–2011)

Recently, we have shown that the contents of total nucleated cells (TNCs) and CD34⁺ hematopoietic stem and progenitor cells (CD34⁺ HSPCs) as well as the cord blood volume (CBV) in umbilical cord blood (UCB) show a circadecadal (~10 years) rhythm of oscillation. This observation was based on an analysis of 17,936 cord blood donations collected during 1999–2011. The aim of the present study was to investigate whether this circadecadal rhythm of oscillation in TNCs, CD34⁺ HSPCs and CBV is related to geomagnetic activity. For the analysis, the yearly averages of TNCs, CD34⁺ HSPCs and CBV in UCB were correlated with geomagnetic activity (Dcx index). Our analysis revealed that (i) all three UCB parameters were statistically significantly correlated with the level of geomagnetic activity, (ii) CBV showed a linear correlation with the Dcx index (r = 0.5290), (iii) the number of TNCs and CD34⁺ HSPCs were quadratic inversely correlated with the Dcx index (r = ?0.5343 and r = ?0.7749, respectively). Furthermore, (iv) CBV and the number of TNCs were not statistically significantly correlated with the number of either modest or intense geomagnetic storms per year, but (v) the number of CD34⁺ HSPCs was statistically significantly correlated with the number of modest (r = 0.9253) as well as intense (r = 0.8683) geomagnetic storms per year. In conclusion, our study suggests that UCB parameters correlate with the state of the geomagnetic field (GMF) modulated by solar activity. Possible biophysical mechanisms underlying this observation, as well as the outcome of these findings, are discussed.     

The Impact of Menstrual Cycle Phase on Economic Choice and Rationality

It is well known that hormones affect both brain and behavior, but less is known about the extent to which hormones affect economic decision-making. Numerous studies demonstrate gender differences in attitudes to risk and loss in financial decision-making, often finding that women are more loss and risk averse than men. It is unclear what drives these effects and whether cyclically varying hormonal differences between men and women contribute to differences in economic preferences. We focus here on how economic rationality and preferences change as a function of menstrual cycle phase in women. We tested adherence to the Generalized Axiom of Revealed Preference (GARP), the standard test of economic rationality. If choices satisfy GARP then there exists a well-behaved utility function that the subject’s decisions maximize. We also examined whether risk attitudes and loss aversion change as a function of cycle phase. We found that, despite large fluctuations in hormone levels, women are as technically rational in their choice behavior as their male counterparts at all phases of the menstrual cycle. However, women are more likely to choose risky options that can lead to potential losses while ovulating; during ovulation women are less loss averse than men and therefore more economically rational than men in this regard. These findings may have market-level implications: ovulating women more effectively maximize expected value than do other groups.     

Towards alien plant prioritization in Italy: methodological issues and first results

In recent decades, multiple actions have been taken to counteract the relentless expansion of invasive alien species as well as to gain a better understanding of their effects on ecosystems. Here, we describe the approach designed by the Italian Botanical Society that is aimed at selecting a list of candidate alien plants to be subjected to a prioritization procedure. We selected a total of 96 species on the basis of data related to their occurrence on both a national and regional scale, their invasiveness and their potential to invade plant communities and/or habitats of community concern. This list represents the first result obtained by applying this standardized workflow and is a first step towards the identification of those alien species that should be included in the national list according to Regulation (EU) n. 1143/2014.     

Treatment by glyphosate-based herbicide allowed recovering native species after Oxalis pes-caprae L. invasion: indications from a Mediterranean island

Biological invasions represent a global threat to biodiversity. Particular attention should be devoted to the management of alien plants, focusing on the opportunity to obtain a rapid response to invasion and restoration of the invaded areas. In this study we aimed to evaluate five different methods for controlling Oxalis pes-caprae, a well-known invasive plant native to South Africa, also focusing on the restoration of the native flora. We set an experiment on the island of Montecristo (central Mediterranean). Treatment methods varied from chemical to low risk methods, including manual removal, covering with mulching sheets, and foliar spraying with acetic acid (30% solution) and two different concentrations of glyphosate (3 and 5% solutions, respectively). The total cover of O. pes-caprae and of other native plants was sampled before treatments, and then several times during the subsequent year; while the plant species composition was sampled in late winter (March 2015–2016) and late spring (May 2015–2016). The use of glyphosate was found to be the only efficient control method, leading to a significant decrease in O. pes-caprae cover as well as to a recovery in native species cover and richness. The effect of the other control methods was negligible.     

The Complex Contributions of Genetics and Nutrition to Immunity in Drosophila melanogaster

Both malnutrition and undernutrition can lead to compromised immune defense in a diversity of animals, and “nutritional immunology” has been suggested as a means of understanding immunity and determining strategies for fighting infection. The genetic basis for the effects of diet on immunity, however, has been largely unknown. In the present study, we have conducted genome-wide association mapping in Drosophila melanogaster to identify the genetic basis for individual variation in resistance, and for variation in immunological sensitivity to diet (genotype-by-environment interaction, or GxE). D. melanogaster were reared for several generations on either high-glucose or low-glucose diets and then infected with Providencia rettgeri, a natural bacterial pathogen of D. melanogaster. Systemic pathogen load was measured at the peak of infection intensity, and several indicators of nutritional status were taken from uninfected flies reared on each diet. We find that dietary glucose level significantly alters the quality of immune defense, with elevated dietary glucose resulting in higher pathogen loads. The quality of immune defense is genetically variable within the sampled population, and we find genetic variation for immunological sensitivity to dietary glucose (genotype-by-diet interaction). Immune defense was genetically correlated with indicators of metabolic status in flies reared on the high-glucose diet, and we identified multiple genes that explain variation in immune defense, including several that have not been previously implicated in immune response but which are confirmed to alter pathogen load after RNAi knockdown. Our findings emphasize the importance of dietary composition to immune defense and reveal genes outside the conventional “immune system” that can be important in determining susceptibility to infection. Functional variation in these genes is segregating in a natural population, providing the substrate for evolutionary response to pathogen pressure in the context of nutritional environment.