Current and future variations of nutrient depositions and influences on tree growth

Current nutrient deposition shows episodic variations which likely may impact the local nutrient cycle at the RBSF. Comparing analyses of deposition data during present-day atmospheric circulation and phases of high biomass burning in the Amazon, characteristic relationships between remote emissions and local deposition are determined. By using projections drawn from the special report on emission scenarios (SRES) in combination with a trajectory modeling tool, future nutrient deposition conditions of the mountain ecosystem are assessed. Observations of relations between climatic variables, current time series of nutrient deposition, and tree growth point to an impact of the remote fertilization effect of atmospheric matters, emitted primarily by human activities like biomass burning and agricultural and industrial sources. The increasing emissions in the future may have adverse effects on the ecosystem in the long run.

Surface charge of polymer coated SPIONs influences the serum protein adsorption, colloidal stability and subsequent cell interaction in vitro

It is known that the nanoparticle-cell interaction strongly depends on the physicochemical properties of the investigated particles. In addition, medium density and viscosity influence the colloidal behaviour of nanoparticles. Here, we show how nanoparticle-protein interactions are related to the particular physicochemical characteristics of the particles, such as their colloidal stability, and how this significantly influences the subsequent nanoparticle-cell interaction in vitro. Therefore, different surface charged superparamagnetic iron oxide nanoparticles were synthesized and characterized. Similar adsorbed protein profiles were identified following incubation in supplemented cell culture media, although cellular uptake varied significantly between the different particles. However, positively charged nanoparticles displayed a significantly lower colloidal stability than neutral and negatively charged particles while showing higher non-sedimentation driven cell-internalization in vitro without any significant cytotoxic effects. The results of this study strongly indicate therefore that an understanding of the aggregation state of NPs in biological fluids is crucial in regards to their biological interaction(s).

Food Politics: How the Food Industry Influences Nutrition and Health, Revised and Expanded Edition

A review of Food Politics: How the Food Industry Influences Nutrition, and Health, Revised and Expanded Edition.

Skills training and social influences for violence prevention in middle schools: A curriculum evaluation

This pilot study evaluated the effect of skills training and of social influences on self-reported aggressive behavior in a sample of 239 sixth-grade students. The effect of two intervention groups and one control group were compared. In the first intervention group, a 15-session, violence-prevention curriculum was taught by the teacher. In the second intervention group, the same curriculum was taught by the teacher with the assistance of peer leaders trained to modify social norms about violence. The control group was evaluated but did not receive any training. The design included four schools. In two schools, three classes were assigned to one of the two interventions or to the control group. In the other two schools, two classes were assigned to either intervention (teacher only) or control. Students were evaluated before and after the implementation of the curriculum using a standardized questionnaire.^ The primary outcome was the effect of the curriculum and peer leaders on self-reported aggressive behaviors. The secondary outcome was their impact on intervening variables: knowledge about violence, conflict-resolution skills, self-efficacy, and attitudes.^ The intervention had a moderate effect on reducing self-reported aggressive behaviors among boys in two of the six classes that received the curriculum. Both classes with peer leaders reduced their aggressive behavior, but this reduction was significant in only one. A peer leader selection problem could probably explain this lack of effect.^ In three of the four schools, both interventions had an overall significant effect on increasing knowledge about violence and skills to reduce violence. Students also developed a more negative attitude toward violence after the intervention. As hypothesized, attitude change was stronger among students from the teacher plus peer leader group. No intervention effect was observed on self-efficacy nor on attitudes toward skills to reduce violence. Limitations of the study and implications for violence prevention in schools are discussed. ^

The craniosacral progression of muscle development influences the emergence of neuromuscular junction alterations in a severe murine model for spinal muscular atrophy.

AIMS As 4-day-old mice of the severe spinal muscular atrophy (SMA) model (dying at 5-8 days) display pronounced neuromuscular changes in the diaphragm but not the soleus muscle, we wanted to gain more insight into the relationship between muscle development and the emergence of pathological changes and additionally to analyse intercostal muscles which are affected in human SMA. METHODS Structures of muscle fibres and neuromuscular junctions (NMJs) of the diaphragm, intercostal and calf muscles of prenatal (E21) and postnatal (P0 and P4) healthy and SMA mice were analysed by light and transmission electron microscopy. NMJ innervation was studied by whole mount immunofluorescence in diaphragms of P4 mice. RESULTS During this period, the investigated muscles still show a significant neck-to-tail developmental gradient. The diaphragm and calf muscles are most and least advanced, respectively, with respect to muscle fibre fusion and differentiation. The number and depth of subsynaptic folds increases, and perisynaptic Schwann cells (PSCs) acquire a basal lamina on their outer surface. Subsynaptic folds are connected to an extensive network of tubules and beaded caveolae, reminiscent of the T system in adult muscle. Interestingly, intercostal muscles from P4 SMA mice show weaker pathological involvement (that is, vacuolization of PSCs and perineurial cells) than those previously described by us for the diaphragm, whereas calf muscles show no pathological changes. CONCLUSION SMA-related alterations appear to occur only when the muscles have reached a certain developmental maturity. Moreover, glial cells, in particular PSCs, play an important role in SMA pathogenesis.

A Coastal Transect of McMurdo Dry Valleys (Antarctica) Snow and Firn: Marine and Terrestrial Influences on Glaciochemistry

Samples of snow and firn from accumulation zones on Clark, Commonwealth, Blue and Victoria Upper Glaciers in the McMurdo Dry Valleys (similar to 77-78 degrees S, 161-164 degrees E), Antarctica, are evaluated chemically and isotopically to determine the relative importance of local (site-specific) factors vs regional-scale influences in defining glaciochemistry. Spatial variation in snow and firn chemistry confirms documented trends within individual valleys regarding major-ion deposition relative to elevation and to distance from the coast. Sodium and methylsulfonate (MS-), for example, follow a decreasing gradient with distance from the coast along the axis of Victoria Valley (350-119 mu gL(-1) for Na+; 33-14 mu gL(-1) for MS-); a similar pattern exists between Commonwealth and Newall Glaciers in the Asgaard Range. When comparing major-ion concentrations (e.g. Na-+,Na- MS-, Ca2+) or trace metals (e.g. Al, Fe) among different valleys, however, site-specific exposures to marine and local terrestrial chemical sources play a dominant role. Because chemical signals at all sites respond to particulates with varying mixtures of marine and terrestrial sources, each of these influences on site glaciochemistry must be considered when drawing temporal climate inferences on regional scales.

Genetic susceptibility to increased bacterial translocation influences the response to biological therapy in patients with Crohn's disease

OBJECTIVE: The aetiology of Crohn's disease (CD) has been related to nucleotide-binding oligomerisation domain containing 2 (NOD2) and ATG16L1 gene variants. The observation of bacterial DNA translocation in patients with CD led us to hypothesise that this process may be facilitated in patients with NOD2/ATG16L1-variant genotypes, affecting the efficacy of anti-tumour necrosis factor (TNF) therapies. DESIGN: 179 patients with Crohn's disease were included. CD-related NOD2 and ATG16L1 variants were genotyped. Phagocytic and bactericidal activities were evaluated in blood neutrophils. Bacterial DNA, TNFα, IFNγ, IL-12p40, free serum infliximab/adalimumab levels and antidrug antibodies were measured. RESULTS: Bacterial DNA was found in 44% of patients with active disease versus 23% of patients with remitting disease (p=0.01). A NOD2-variant or ATG16L1-variant genotype was associated with bacterial DNA presence (OR 4.8; 95% CI 1.1 to 13.2; p=0.001; and OR 2.4; 95% CI 1.4 to 4.7; p=0.01, respectively). This OR was 12.6 (95% CI 4.2 to 37.8; p=0.001) for patients with a double-variant genotype. Bacterial DNA was associated with disease activity (OR 2.6; 95% CI 1.3 to 5.4; p=0.005). Single and double-gene variants were not associated with disease activity (p=0.19). Patients with a NOD2-variant genotype showed decreased phagocytic and bactericidal activities in blood neutrophils, increased TNFα levels in response to bacterial DNA and decreased trough levels of free anti-TNFα. The proportion of patients on an intensified biological therapy was significantly higher in the NOD2-variant groups. CONCLUSIONS: Our results characterise a subgroup of patients with CD who may require a more aggressive therapy to reduce the extent of inflammation and the risk of relapse

Influences of porcine circo-, arteriviruses and cathelicidins in plasmacytoid dendritic cell-derived interferon-alpha responses

Type I interferons (IFNs), mainly IFN-α/β play a crucial role in innate defense against viruses. In addition to their direct antiviral activity, type I IFNs have antitumoral and immunomodulatory effects. Although all cells are virtually able to induce IFN-α, the plasmacytoid dendritic cell (pDC) subset represents the ultimate producers of IFN-α as well as other proinflammatory cytokines. Due to the specific expression of TLR7 and TLR9 recognizing single-stranded (ss) RNA and unmethylated CpG motifs respectively, pDCs can secrete up to 1000 times more IFN-α than any cellular types. Additionally, it is well known that several cytokines including type I and II IFNs, Flt3-L, IL-4 and GM-CSF favor pDC-derived IFN-α responses to unmethylated CpG motifs. In a first step, we aimed to characterize and clarify the interactions of two porcine viruses with pDCs. The double-stranded DNA replicative forms of porcine circovirus type 2 (PCV2) were demonstrated to inhibit CpG-induced IFN- α by pDCs. Our study showed that none of the cytokines known to enhance pDC responsiveness can counter-regulate the PCV2-mediated inhibition of IFN-α induced by CpG, albeit IFN-γ significantly reduced the level of inhibition. Interestingly, the presence of IFN-γ enabled pDCs to induce IFN-α to low doses of PCV2. We also noted that after DNase treatment, PCV2 preparations were still able to stimulate pDCs. These data suggest that encapsulated viral ssDNA promotes the induction of IFN-α in pDCs treated with IFN-γ whereas free DNA, presumably as double-stranded forms, was responsible for inhibiting pDC responses. Regarding PRRSV, it has been reported that North American isolates did not induce and even inhibited IFN-α response in pDCs. However, PRRSV infection was also shown to lead to an induction of IFN-α in the serum and in the lungs suggesting that certain cells are responsive to the virus. Contrasting to previous reports we found that numerous PRRSV isolates directly induced IFN-α in pDCs. This response was still observed after UV-inactivation of viruses and required TLR7 signaling. The inhibition of CpG-induced IFN-α was weak and strain dependent, again contrasting with a previous report. We also observed that IFN-γ and IL-4 enhanced IFN-α response to two prototype strains, VR-2332 and LVP23. In summary, we demonstrated that both PCV2 and PRRSV promote IFN-α secretion in pDCs in vitro suggesting that IFN-α detected in PCV2- or PRRSV-infected animal might originate from pDCs. On the other hand, PRRSV replication is restricted to the macrophage (MΦ) lineage. These innate immune cells represent a heterogeneous population which can be induce to “classical” (M1) and “alternative” (M2) activated MΦ acquiring inflammatory or “wound-healing” functional properties, respectively. Nonetheless, little is known about the effect of polarization into M1 or M2 and the susceptibility of these cells to PRRSV. Thus, we examined the impact of cytokine on MΦ polarization into M1 or M2. Infections of these cells by several PRRSV isolates enabled the discrimination of PRRSV isolate in a genotype- and irulencedependent manner in M1 and IFN-β-activated MΦ. In contrast, the expression of PRRSV nucleocapsid in M2 or inactivated MΦ was indistinguishable among the PRRSV isolates tested. In the last part of my Thesis, we investigated the influence of three synthetic porcine cathelicidin peptides for their ability to deliver nucleic acid to pDCs. We reported that all cathelicidins tested can complex and quickly deliver nucleic acids resulting in IFN-α induction. Moreover, we show that the typical α- helical amphipathic conformation is required to mediate killing of bacteria but not for inducing IFN-α secretion by pDCs. Furthermore, we found that E.coli treated with one of these cathelicidins is able to induce significantly higher levels of IFN-α compared to a non-sense version of the peptide. These data suggest that cathelicidins could influence the immune response in a two-step process. First, these peptides target bacteria leading to cell lysis. In turn, cathelicidins form complexes and deliver extracellular microbial nucleic acids released into pDCs. These pDC-derived IFN-α responses could be of particular relevance in driving the adaptive immune responses against microbial infections.