A case study of a density structure over a vertical magnetic field region in the Martian ionosphere

One of the discoveries made by the radar sounder on the Mars Express spacecraft is the existence of magnetically controlled structures in the ionosphere of Mars, which result in bulges in the ionospheric electron density contours. These bulges lead in turn to oblique echoes, which show up as hyperbola-shaped features in the echograms. A hyperbola-shaped feature observed over an isolated region of strong crustal magnetic field is associated with a plasma cavity in the upper ionosphere and a corresponding density enhancement in the lower levels of the ionosphere. We suggest that along open magnetic field lines, the solar wind electrons are accelerated downward and the ionospheric ions are accelerated upward in a manner similar to the field line-driven auroral acceleration at Earth. This heating due to precipitating electrons may cause an increase in the scale height and may drive a loss of ionospheric plasma at high altitudes

Cytokine pathway disruption in a mouse model of schizophrenia induced by Munc18-1a overexpression in the brain

Background: An accumulating body of evidence points to the significance of neuroinflammation and immunogenetics in schizophrenia, and an imbalance of cytokines in the central nervous system (CNS) has been suggested to be associated with the disorder. Munc18-overexpressing mice (Munc18-OE) have provided a model for the study of the alterations that may underlie the symptoms of subjects with schizophrenia. The aim of the present study was to elucidate the involvement of neuroinflammation and cytokine imbalance in this model. Methods: Cytokines were evaluated in the cortex and the striatum of Munc18-OE and wild-type (WT) mice by enzyme-linked immunosorbent assay (ELISA). Protein levels of specific microglia and macrophage, astrocytic and neuroinflammation markers were quantified by western blot in the cortex and the striatum of Munc18-OE and WT mice. Results: Each cytokine evaluated (Interferon-gamma (IFN-γ), Tumor Necrosis Factor-alpha (TNF-α), Interleukin-2 (IL-2) and CCL2 chemokine) was present at higher levels in the striatum of Munc18-OE mice than WT. Cortical TNF-α and IL-2 levels were significantly lower in Munc18-OE mice than WT mice. The microglia and macrophage marker CD11b was lower in the cortexes of Munc18-OE mice than WT, but no differences were observed in the striatum. Glial Fibrillary Acidic Protein (GFAP) and Nuclear Factor-kappaB (NF-κB)p65 levels were not different between the groups. Interleukin-1beta (IL-1β) and IL-6 levels were beneath detection limits. Conclusions: The disrupted levels of cytokines detected in the brain of Munc18-OE mice was found to be similar to clinical reports and endorses study of this type for analysis of this aspect of the disorder. The lower CD11b expression in the cortex but not in the striatum of the Munc18-OE mice may reflect differences in physiological activity. The cytokine expression pattern observed in Munc18-OE mice is similar to a previously published model of schizophrenia caused by maternal immune activation. Together, these data suggest a possible role for an immune imbalance in this disorder

Plasmid conjugation from Proteobacteria as evidence for the origin of xenologous genes in Cyanobacteria

Comparative genomics showed that 5% of Synechococcus elongatus PCC 7942 genes are of probable proteobacterial origin. To investigate the role of inter-phylum conjugation in cyanobacterial gene acquisition, we tested the ability of a set of prototype proteobacterial conjugative plasmids (RP4, pKM101, R388, R64 and F) to transfer DNA from E. coli to S. elongatus. A series of BioBrick-compatible, mobilizable shuttle vectors was developed. These vectors were based on the putative origin of replication of the Synechococcus resident plasmid pANL. Not only broad-host range plasmids, such as RP4 and R388, but also narrower host-range plasmids, such as pKM101, all encoding MPFT-type IV secretion systems, were able to transfer plasmid DNA from E. coli to S. elongatus by conjugation. Neither MPFF, nor MPFI could be used as interphylum DNA delivery agents. Reciprocally, pANL-derived cointegrates could be introduced in E. coli by electroporation, where they conferred a functional phenotype. These results suggest the existence of potentially ample channels of gene flow between Proteobacteria and Cyanobacteria and point to MPFT-based inter-phylum conjugation as a potential mechanism to explain the proteobacterial origin of a majority of S. elongatus xenologous genes

Rapid rise in toxic load for bees revealed by analysis of pesticide use in Great Britain

A strong argument can be made that the European Union has the most rigorous regulatory system for pesticides in the world, and that modern pesticide use poses fewer environmental threats than older regimes. Nevertheless, the impacts of pesticides on bees and other non-target organisms are much debated in Europe as elsewhere. Here we document changing patterns of pesticide use in arable and horticultural crops in Great Britain from 1990 to 2015. The weight of pesticides used has approximately halved over this period, but in contrast the number of applications per field nearly doubled. The total potential kill of honeybees (the total number of LD50 doses applied to the 4.6 million hectares of arable farmland in Great Britain each year) increased six-fold to approximately 3 1016 bees, the result of the increasing use of neonicotinoids from 1994 onwards which more than offset the effect of declining organophosphate use. It is important to stress that this does not mean that this number of bees will be killed, and also to acknowledge that our simple analysis does not take into account many factors such as differences in persistence, and timing and mode of application of pesticides, which will affect actual exposure of non-target organisms. Nonetheless, all else being equal, these data suggest that the risk posed by pesticides to non-target insects such as bees, other pollinators and natural enemies of pests, has increased considerably in the last 26 years

Ornamental plants on sale to the public are a significant source of pesticide residues with implications for the health of pollinating insects

Garden centres frequently market nectar- and pollen-rich ornamental plants as “pollinator-friendly”, however these plants are often treated with pesticides during their production. There is little information on the nature of pesticide residues present at the point of purchase and whether these plants may actually pose a threat to, rather than benefit, the health of pollinating insects. Using mass spectrometry analyses, this study screened leaves from 29 different ‘bee-friendly’ plants for 8 insecticides and 16 fungicides commonly used in ornamental production. Only two plants (a Narcissus and a Salvia variety) did not contain any pesticide and 23 plants contained more than one pesticide, with some species containing mixtures of 7 (Ageratum houstonianum) and 10 (Erica carnea) different agrochemicals. Neonicotinoid insecticides were detected in more than 70% of the analysed plants, and chlorpyrifos and pyrethroid insecticides were found in 10% and 7% of plants respectively. Boscalid, spiroxamine and DMI-fungicides were detected in 40% of plants. Pollen samples collected from 18 different plants contained a total of 13 different pesticides. Systemic compounds were detected in pollen samples at similar concentrations to those in leaves. However, some contact (chlorpyrifos) and localised penetrant pesticides (iprodione, pyroclastrobin and prochloraz) were also detected in pollen, likely arising from direct contamination during spraying. The neonicotinoids thiamethoxam, clothianidin and imidacloprid and the organophosphate chlorpyrifos were present in pollen at concentrations between 6.9 and 81 ng/g and at levels that overlap with those known to cause harm to bees. The net effect on pollinators of buying plants that are a rich source of forage for them but simultaneously risk exposing them to a cocktail of pesticides is not clear. Gardeners who wish to gain the benefits without the risks should seek uncontaminated plants by growing their own from seed, plant-swapping or by buying plants from an organic nursery

Risk-taking and reasons for living in non-clinical Italian university students.

The associations between risk-taking, hopelessness, and reasons for living were explored in a sample of 312 Italian students. Respondents completed the Physical Risk Assessment Inventory, the Physical Risk-Taking Behavior Inventory, the Beck Hopelessness Scale, and the Reasons for Living Inventory. Students with lower scores on the Reasons for Living Inventory and higher scores on the Beck Hopelessness Scale rated the risky activities as less risky and engaged in them more often. Women obtained higher scores on risk assessment, lower scores on personal risk-taking and higher scores on the Reasons for Living Inventory and most of its subscales. Men in general and people who take risks and perceive lower risk are more hopeless and relatively weak in reasons for living

Larval exposure to the neonicotinoid imidacloprid impacts adult size in the farmland butterfly Pieris brassicae

Populations of farmland butterflies have been suffering from substantial population declines in recent decades. These declines have been correlated with neonicotinoid usage both in Europe and North America but experimental evidence linking these correlations is lacking. The potential for non-target butterflies to be exposed to trace levels of neonicotinoids is high, due to the widespread contamination of agricultural soils and wild plants in field margins. Here we provide experimental evidence that field realistic, sub-lethal exposure to the neonicotinoid imidacloprid negatively impacts the development of the common farmland butterfly Pieris brassicae. Cabbage plants were watered with either 0, 1, 10, 100 or 200 parts per billion imidacloprid, to represent field margin plants growing in contaminated agricultural soils and these were fed to P. brassicae larvae. The approximate digestibility (AD) of the cabbage as well as behavioural responses by the larvae to simulated predator attacks were measured but neither were affected by neonicotinoid treatment. However, the duration of pupation and the size of the adult butterflies were both significantly reduced in the exposed butterflies compared to the controls, suggesting that adult fitness is compromised through exposure to this neonicotinoid