PLGA, PLGA-TMC and TMC-TPP nanoparticles differentially modulate the outcome of nasal vaccination by inducing tolerance or enhancing humoral immunity

Development of vaccines in autoimmune diseases has received wide attention over the last decade. However, many vaccines showed limited clinical efficacy. To enhance vaccine efficacy in infectious diseases, biocompatible and biodegradable polymeric nanoparticles have gained interest as antigen delivery systems. We investigated in mice whether antigen-encapsulated PLGA (poly-lactic-co-glycolic acid), PLGA-TMC (N-trimethyl chitosan) or TMC-TPP (tri-polyphosphate) nanoparticles can also be used to modulate the immunological outcome after nasal vaccination. These three nanoparticles enhanced the antigen presentation by dendritic cells, as shown by increased in vitro and in vivo CD4(+) T-cell proliferation. However, only nasal PLGA nanoparticles were found to induce an immunoregulatory response as shown by enhanced Foxp3 expression in the nasopharynx associated lymphoid tissue and cervical lymph nodes. Nasal administration of OVA-containing PLGA particle resulted in functional suppression of an OVA-specific Th-1 mediated delayed-type hypersensitivity reaction, while TMC-TPP nanoparticles induced humoral immunity, which coincided with the enhanced generation of OVA-specific B-cells in the cervical lymph nodes. Intranasal treatment with Hsp70-mB29a peptide-loaded PLGA nanoparticles suppressed proteoglycan-induced arthritis, leading to a significant reduction of disease. We have uncovered a role for PLGA nanoparticles to enhance CD4(+) T-cell mediated immunomodulation after nasal application. The exploitation of this differential regulation of nanoparticles to modulate nasal immune responses can lead to innovative vaccine development for prophylactic or therapeutic vaccination in infectious or autoimmune diseases.     

Obesity and Persistent Organic Pollutants: Possible Obesogenic Effect of Organochlorine Pesticides and Polychlorinated Biphenyls

Persistent organic pollutants (POPs) are endocrine‐disrupting chemicals associated with the development of the metabolic syndrome and type 2 diabetes. In humans, little is known about their role in the potential origin of obesity. This study aims to assess the associations between serum levels of POPs and the prevalence of obesity in a cohort of obese and lean adult men and women. POP serum samples were investigated cross‐sectionally in 98 obese and 47 lean participants, aged ≥18 years. Serum samples were analyzed for the presence of polychlorinated biphenyl (PCB) congeners 153, 138, 180, and 170 and for the organochlorine pesticides, dichloro‐diphenyl‐dichloroethylene (pp‐DDE), and β‐hexachlorocyclohexane (βHCH). We established a significant negative correlation between BMI, waist, fat mass percentage, total and subcutaneous abdominal adipose tissue, and serum levels of PCB 153, 180, 170, and the sumPCBs. For βHCH, we demonstrated a positive correlation with BMI, waist, fat mass percentage, and total and subcutaneous abdominal adipose tissue. PCBs 180, 170, and the sum of PCBs correlated significantly negative with homeostasis model assessment for insulin resistance (HOMA_IR). βHCH correlated significantly positively with HOMA_IR. A strong correlation was established between all POP serum levels and age. We established a positive relationship between high serum levels of βHCH and BMI and HOMA_IR, whereas serum PCB levels were inversely correlated with BMI and HOMA_IR. Combined, these results suggest that the diabetogenic effect of low‐dose exposure to POPs might be more complicated than a simple obesogenic effect.     

Nutrient utilization by bovine articular chondrocytes: a combined experimental and theoretical approach

A combined experimental-numerical approach was adopted to characterize glucose and oxygen uptake and lactate production by bovine articular chondrocytes in a model system. For a wide range of cell concentrations, cells in agarose were supplemented with either low or high glucose medium. During an initial culture phase of 48 h, oxygen was monitored noninvasively using a biosensor system. Glucose and lactate were determined by medium sampling. In order to quantify glucose and oxygen uptake, a finite element approach was adopted to describe diffusion and uptake in the experimental model. Numerical predictions of lactate, based on simple relations for cell metabolism, were found to agree well for low glucose, but not for high glucose medium. Oxygen did not play a role in either case. Given the close association between chondrocyte energy metabolism and matrix synthesis, a quantifiable prediction of utilization can present a valuable contribution in the optimization of tissue engineering conditions.     

Haploid vegetative mycelia of Armillaria gallica show among-cell-line variation for growth and phenotypic plasticity

Vegetative mycelial cells of Armillaria are expected to have diploid nuclei. Cells from a single mycelium therefore would not be expected to differ from one another for ecologically relevant quantitative traits. We isolated two sets of basidiome cell lines (from spores and stipe cells) and one set of vegetative cell lines (from an attached rhizomorph) from a single contiguous Armillaria gallica mycelium. We isolated a second set of vegetative cell lines from the soil 20 cm from the above basidiome-rhizomorph complex. In all four sets of cell lines in situ DAPI-DNA measurements showed cells are haploid and quantitative-trait analyses of cell lines grown at different water potentials revealed high levels of among-cell-line genetic variation for both growth and phenotypic plasticity. Haploidy and the existence of ecologically relevant genetic variation within vegetative individuals are unexpected and mean that a process similar to evolutionary adaptation could take place within the soma of a genetic individual. We believe this is a key to understanding how large A. gallica mycelia survive exposure to variation in ecological conditions during lives that potentially span several tree (host) generations.     

Evolution of reproductive-immune interactions

The comparative approach in biological sciences has providedvaluable insights into the role of different organ systems inadaptation and evolution, and seeks to establish unifying themes.This approach also plays a key role in identifying model speciesand systems for the study of specific questions and problems.Further, by applying the concept of homology, information aboutnonmammalian species may be used either to directly understandmammalian/human regulatory processes, or to formulate hypothesesfor direct testing. Individual physiological systems functionin a milieu provided by the integrated activities of all ofthe systems to adapt, adjust and sustain the organism in itsenvironment. The overlapping interfaces between the differentphysiological systems provide fertile ground for new insightsand to enhance our knowledge. These interdisciplinary areasare of great importance if we are to understand the full complexityof organismal function. Of particular interest are the interactionsbetween the reproductive system and the immune system. The reproductivesystem is unique in that its primary role is to assure the continuityof the species, while the immune system provides internal protectionand thus facilitates continued health and survival. The modusoperandi of these 2 morphologically diffuse systems involveswidely distributed chemical signals in response to environmentalinput, and both systems must interact for the normal functioningof each. While the major focus of reproductive–immuneresearch has historically been with mammals, and has providedsubstantial insight into the interactions between these physiologicalsystems, comparative studies offer unique perspectives. Further,dysregulation of normal physiological interactions between thereproductive and immune systems can lead to disorders and diseaseseffecting one system or the other. Thus, comparative studiesof these interactions may shed some light upon the evolutionarymechanisms involved in such cases.     

Real-time observation of DNA looping dynamics of Type IIE restriction enzymes NaeI and NarI

Many restriction enzymes require binding of two copies of a recognition sequence for DNA cleavage, thereby introducing a loop in the DNA. We investigated looping dynamics of Type IIE restriction enzymes NaeI and NarI by tracking the Brownian motion of single tethered DNA molecules. DNA containing two endonuclease recognition sites spaced a few 100 bp apart connect small polystyrene beads to a glass surface. The position of a bead is tracked through video microscopy. Protein-mediated looping and unlooping is then observed as a sudden specific change in Brownian motion of the bead. With this method we are able to directly follow DNA looping kinetics of single protein–DNA complexes to obtain loop stability and loop formation times. We show that, in the absence of divalent cations, NaeI induces DNA loops of specific size. In contrast, under these conditions NarI mainly creates non-specific loops, resulting in effective DNA compaction for higher enzyme concentrations. Addition of Ca²⁺ increases the NaeI-DNA loop lifetime by two orders of magnitude and stimulates specific binding by NarI. Finally, for both enzymes we observe exponentially distributed loop formation times, indicating that looping is dominated by (re)binding the second recognition site.     

Cultivation of Denitrifying Bacteria: Optimization of Isolation Conditions and Diversity Study

An evolutionary algorithm was applied to study the complex interactions between medium parameters and their effects on the isolation of denitrifying bacteria, both in number and in diversity. Growth media with a pH of 7 and a nitrogen concentration of 3 mM, supplemented with 1 ml of vitamin solution but not with sodium chloride or riboflavin, were the most successful for the isolation of denitrifiers from activated sludge. The use of ethanol or succinate as a carbon source and a molar C/N ratio of 2.5, 20, or 25 were also favorable. After testing of 60 different medium parameter combinations and comparison with each other as well as with the standard medium Trypticase soy agar supplemented with nitrate, three growth media were highly suitable for the cultivation of denitrifying bacteria. All evaluated isolation conditions were used to study the cultivable denitrifier diversity of activated sludge from a municipal wastewater treatment plant. One hundred ninety-nine denitrifiers were isolated, the majority of which belonged to the Betaproteobacteria (50.4%) and the Alphaproteobacteria (36.8%). Representatives of Gammaproteobacteria (5.6%), Epsilonproteobacteria (2%), and Firmicutes (4%) and one isolate of the Bacteroidetes were also found. This study revealed a much more diverse denitrifying community than that previously described in cultivation-dependent research on activated sludge.     

Vicissitudes of benefit sharing of crop genetic resources: downstream and upstream

In this article, we will first give a historic overview of the concept of benefit sharing and its appearance in official agreements, particularly with respect to crop genetic resources. It will become clear that, at present, benefit sharing is primarily considered as an instrument of compensation or exchange, and thus refers to commutative justice. However, we believe that such a narrow interpretation of benefit sharing disregards, and even undermines, much of its (historical) content and potency, especially where crop genetic resources are concerned. We argue that benefit sharing should not be based merely on commutative justice but rather on a broader model that is also grounded in the concept of distributive justice. This has repercussions for the application of benefit sharing, which we try to clarify by distinguishing between downstream and upstream benefit sharing. Upstream benefit sharing is not so much inspired by compensation for actions done, or the distribution downstream of benefits developed, but by the idea of shared decision-making on the research and development of resources fundamental to human welfare. Going upstream in the research process of crop genetic resources, and determining research agendas and improving crops according to the needs of the poor, benefit sharing may well be a tool to contribute to world food security and global justice. We concretize our ideas on upstream benefit sharing by introducing a set of criteria that determine the success of consultations on agricultural research agenda setting.