Explaining variability in the production of seed and allergenic pollen by invasive <Emphasis Type="Italic">Ambrosia artemisiifolia</Emphasis> across Europe

To better manage invasive populations, it is vital to understand the environmental drivers underlying spatial variation in demographic performance of invasive individuals and populations. The invasive common ragweed, Ambrosia artemisiifolia, has severe adverse effects on agriculture and human health, due to its vast production of seeds and allergenic pollen. Here, we identify the scale and nature of environmental factors driving individual performance of A. artemisiifolia, and assess their relative importance. We studied 39 populations across the European continent, covering different climatic and habitat conditions. We found that plant size is the most important determinant in variation of per-capita seed and pollen production. Using plant volume as a measure of individual performance, we found that the local environment (i.e. the site) is far more influential for plant volume (explaining 25% of all spatial variation) than geographic position (regional level; 8%) or the neighbouring vegetation (at the plot level; 4%). An overall model including environmental factors at all scales performed better (27%), including the weather (bigger plants in warm and wet conditions), soil type (smaller plants on soils with more sand), and highlighting the negative effects of altitude, neighbouring vegetation and bare soil. Pollen and seed densities varied more than 200-fold between sites, with highest estimates in Croatia, Romania and Hungary. Pollen densities were highest on arable fields, while highest seed densities were found along infrastructure, both significantly higher than on ruderal sites. We discuss implications of these findings for the spatial scale of management interventions against A. artemisiifolia.     

Temporal and spatial patterns in the emigrations of the army ant Dorylus (Anomma) molestus in the montane forest of Mt Kenya

Abstract.  1. The emigration behaviour of the army ant Dorylus ( Anomma ) molestus was studied in the montane forest of Mt Kenya. This species forages by massive swarm raids (mean width 10.3 m ± 4.6 m SD), which are assumed to have a strong negative impact on the densities of prey populations.
2. For non-reproductive colonies the stay duration in a nest is highly variable (median 17, range 3–111 days). This suggests that the frequency of emigrations is not dictated by a brood cycle as an underlying endogenous pattern generator.
3. Colony density is high (mean nearest neighbour's distance 82.1 m ± 29.4 m SD) and mean foraging range is 75.0 m, so encounters with neighbouring colonies occur frequently.
4. The straight line emigration distance is on average 92.7 m (± 29.7 SD). The emigration direction is random with respect to absolute bearing and also relative to the direction of the previous emigration. However, the emigration direction is influenced by the location of the nearest neighbour. Colonies typically emigrate directly away from their nearest neighbour.
5. Local food depletion is likely to be the ultimate cause for emigrations in this species, because emigration distance is larger than foraging range and colonies move away from their nearest neighbour. A small percentage of emigrations may be triggered by pangolin attacks on nests.
6. Contrary to the prediction of a recently developed mathematical model for epigaeic swarm-raiding Dorylus ( Anomma ) species, D.  ( A .)  molestus colonies do not engage in intraspecific battles. Possible reasons for the absence of fights between colonies despite apparently fierce intraspecific competition are discussed.     

How Can Inequalities in Mortality Be Reduced? A Quantitative Analysis of 6 Risk Factors in 21 European Populations

Background

Socioeconomic inequalities in mortality are one of the greatest challenges for health policy in all European countries, but the potential for reducing these inequalities is unclear. We therefore quantified the impact of equalizing the distribution of six risk factors for mortality: smoking, overweight, lack of physical exercise, lack of social participation, low income, and economic inactivity.

Methods

We collected and harmonized data on mortality and risk factors by educational level for 21 European populations in the early 2000s. The impact of the risk factors on mortality in each educational group was determined using Population Attributable Fractions. We estimated the impact on inequalities in mortality of two scenarios: a theoretical upward levelling scenario in which inequalities in the risk factor were completely eliminated, and a more realistic best practice scenario, in which inequalities in the risk factor were reduced to those seen in the country with the smallest inequalities for that risk factor.

Findings

In general, upward levelling of inequalities in smoking, low income and economic inactivity hold the greatest potential for reducing inequalities in mortality. While the importance of low income is similar across Europe, smoking is more important in the North and East, and overweight in the South. On the basis of best practice scenarios the potential for reducing inequalities in mortality is often smaller, but still substantial in many countries for smoking and physical inactivity.

Interpretation

Theoretically, there is a great potential for reducing inequalities in mortality in most European countries, for example by equity-oriented tobacco control policies, income redistribution and employment policies. Although it is necessary to achieve substantial degrees of upward levelling to make a notable difference for inequalities in mortality, the existence of best practice countries with more favourable distributions for some of these risk factors suggests that this is feasible.     

Non-invasive In-cell Determination of Free Cytosolic [NAD+]/[NADH] Ratios Using Hyperpolarized Glucose Show Large Variations in Metabolic Phenotypes

Accumulating evidence suggest that the pyridine nucleotide NAD has far wider biological functions than its classical role in energy metabolism. NAD is used by hundreds of enzymes that catalyze substrate oxidation and, as such, it plays a key role in various biological processes such as aging, cell death, and oxidative stress. It has been suggested that changes in the ratio of free cytosolic [NAD⁺]/[NADH] reflects metabolic alterations leading to, or correlating with, pathological states. We have designed an isotopically labeled metabolic bioprobe of free cytosolic [NAD⁺]/[NADH] by combining a magnetic enhancement technique (hyperpolarization) with cellular glycolytic activity. The bioprobe reports free cytosolic [NAD⁺]/[NADH] ratios based on dynamically measured in-cell [pyruvate]/[lactate] ratios. We demonstrate its utility in breast and prostate cancer cells. The free cytosolic [NAD⁺]/[NADH] ratio determined in prostate cancer cells was 4 times higher than in breast cancer cells. This higher ratio reflects a distinct metabolic phenotype of prostate cancer cells consistent with previously reported alterations in the energy metabolism of these cells. As a reporter on free cytosolic [NAD⁺]/[NADH] ratio, the bioprobe will enable better understanding of the origin of diverse pathological states of the cell as well as monitor cellular consequences of diseases and/or treatments.     

Alterations in Growth, Photosynthesis, and Respiration in a Starchless Mutant of Arabidopsis thaliana (L.) Deficient in Chloroplast Phosphoglucomutase Activity

A mutant of Arabidopsis thaliana (L.) Heynh. which lacks leaf starch was isolated by screening for plants which did not stain with iodine. The starchless phenotype, confirmed by quantitative enzymic analysis, is caused by a single recessive nuclear mutation which results in a deficiency of the chloroplast isozyme of phosphoglucomutase. When grown in a 12-h photoperiod, leaves of the wild-type accumulated substantial amounts of starch but lower levels of soluble sugars. Under these conditions, the mutant accumulated relatively high levels of soluble sugars. Rates of growth and net photosynthesis of the mutant and wild-type were indistinguishable when the plants were grown in constant illumination. However, in a short photoperiod, the growth of the mutant was severely impaired, the rate of photosynthesis was depressed relative to the wild-type, and the rate of dark respiration, which was high following the onset of darkness, exhibited an uncharacteristic decay throughout the dark period. The altered control of respiration by the mutant, which may be related to the relatively high levels of soluble carbohydrate that accumulate in the leaf and stem tissue, is believed to be partially responsible for the low growth rate of the mutant in short days. The depressed photosynthetic capacity of the mutant may also reflect a metabolic adaptation to the accumulation of high levels of soluble carbohydrate which mimics the effects of alterations in source/sink ratio. The activities of sucrose phosphate synthase and acid invertase are significantly higher in the mutant than in the wild-type whereas ADP-glucose pyrophosphorylase activity is lower. This suggests that the activities of these enzymes may be modulated in response to metabolite concentrations or flux through the pathways.     

ReSynPlex: Respiratory Syndrome Linked Pathogens Multiplex Detection and Characterization

Background

Pneumonia is a common disease that is a leading cause of mortality worldwide and frequently requires hospital admission. A large number of infectious agents may be involved and as a result of the potential severity of the infection, a clear and quick diagnostic is mandatory in order to take the appropriate decision for the health of the patient. However, a real gap exists between the multiplicity of information required by the practitioner and the diagnostic tools available.

A GLRA1 null mutation in recessive hyperekplexia challenges the functional role of glycine receptors.

Dominant missense mutations in the human glycine receptor (GlyR) alpha 1 subunit gene (GLRA1) give rise to hereditary hyperekplexia. These mutations impair agonist affinities and change conductance states of expressed mutant channels, resulting in a partial loss of function. In a recessive case of hyperekplexia, we found a deletion of exons 1-6 of the GLRA1 gene. Born to consanguineous parents, the affected child is homozygous for this GLRA1(null) allele consistent with a complete loss of gene function. The child displayed exaggerated startle responses and pronounced head-retraction jerks reflecting a disinhibition of vestigial brain-stem reflexes. In contrast, proprio- and exteroceptive inhibition of muscle activity previously correlated to glycinergic mechanisms were not affected. This case demonstrates that, in contrast to the lethal effect of a null allele in the recessive mouse mutant oscillator (Glra1 spd-ot), the loss of the GlyR alpha 1 subunit is effectively compensated in man.