The right response at the right time: Exploring helminth immune modulation in sticklebacks by experimental coinfection

Parasites are one of the strongest selective agents in nature. They select for hosts that evolve counter‐adaptive strategies to cope with infection. Helminth parasites are special because they can modulate their hosts’ immune responses. This phenomenon is important in epidemiological contexts, where coinfections may be affected. How different types of hosts and helminths interact with each other is insufficiently investigated. We used the three‐spined stickleback (Gasterosteus aculeatus) – Schistocephalus solidus model to study mechanisms and temporal components of helminth immune modulation. Sticklebacks from two contrasting populations with either high resistance (HR) or low resistance (LR) against S. solidus, were individually exposed to S. solidus strains with characteristically high growth (HG) or low growth (LG) in G. aculeatus. We determined the susceptibility to another parasite, the eye fluke Diplostomum pseudospathaceum, and the expression of 23 key immune genes at three time points after S. solidus infection. D. pseudospathaceum infection rates and the gene expression responses depended on host and S. solidus type and changed over time. Whereas the effect of S. solidus type was not significant after three weeks, T regulatory responses and complement components were upregulated at later time points if hosts were infected with HG S. solidus. HR hosts showed a well orchestrated immune response, which was absent in LR hosts. Our results emphasize the role of regulatory T cells and the timing of specific immune responses during helminth infections. This study elucidates the importance to consider different coevolutionary trajectories and ecologies when studying host‐parasite interactions.     

Calorimetry for studying the adsorption of proteins in hydrophobic interaction chromatography

Hydrophobic interaction chromatography is a very popular chromatography method for purification of proteins and plasmids in all scales from analytical to industrial manufacturing. Despite this frequent use, the complex interaction mechanism and the thermodynamic aspects of adsorption in hydrophobic interaction chromatography are still not well understood. Calorimetric methods such as isothermal titration calorimetry and flow calorimetry can help to gain a deeper understanding of the adsorption strength, the influence of salt type and temperature. They can be used to study conformational changes of proteins, which are often associated with the adsorption in hydrophobic interaction chromatography. This review offers a detailed introduction into the thermodynamic fundamentals of adsorption in hydrophobic interaction chromatography with a special focus on the potential applications of isothermal titration calorimetry and flow calorimetry for studying specific problems and relationships of the adsorption behavior of proteins and its various influencing factors. Models for characterizing conformational changes upon adsorption are presented together with methods for assessing this problem for different proteins and stationary phases. All of this knowledge can contribute greatly to forming a sound basis for method development, process optimization and finding modelling strategies in hydrophobic interaction chromatography.     

Elevated Prolactin during Pregnancy Drives a Phenotypic Switch in Mouse Hypothalamic Dopaminergic Neurons

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The Sandfish＇s Skin： Morphology, Chemistry and Reconstruction

The sandfish is a lizard having the remarkable ability to move in desert sand in a swimming-like fashion. The most outstanding adaptations to this mode of life are the low friction behaviour and the extensive abrasion resistance of the sandfish skin against sand, outperforming even steel. We investigated the topography, the composition and the mechanical properties of sandfish scales. These consist of glycosylated keratins with high amount of sulphur but no hard inorganic material, such as silicates or lime. Remarkably, atomic force microscopy shows an almost complete absence of attractive forces between the scale surface and a silicon tip, suggesting that this is responsible for the unusual tribological properties. The unusual glycosylation of the keratins was found to be absolutely necessary for the described phenomenon. The scales were dissolved and reconstituted on a polymer surface resulting in properties similar to the original scale. Thus, we provide a pathway towards exploitation of the reconstituted scale material for future engineering applications.     

Simultaneous quantification of voriconazole and posaconazole in human plasma by high-performance liquid chromatography with ultra-violet detection

A sensitive and selective high-performance liquid chromatographic (HPLC) method with ultra-violet detection has been developed and validated for the simultaneous determination of posaconazole and voriconazole, two systemic anti-fungal agents. An internal standard diazepam was added to 100 microL of human plasma followed by 3 mL of hexane-methylene chloride (70:30, v/v). The organic layer was evaporated to dryness and the residue was reconstituted with 100 microL of mobile phase before being injected in the chromatographic system. The compounds were separated on a C8 column using sodium potassium phosphate buffer (0.04 M, pH 6.0): acetonitrile:ultrapure water (45:52.5:2.5, v/v/v) as mobile phase. All compounds were detected at a wavelength of 255 nm. The assay was linear and validated over the range 0.2-10.0 mg/L for voriconazole and 0.05-10.0 mg/L for posaconazole. The biases were comprised between -3 and 5% for voriconazole and -2 and 8% for posaconazole. The intra- and inter-day precisions of the method were lower than 8% for the routine quality control (QC). The mean recovery was 98% for voriconazole and 108% for posaconazole. This method provides a useful tool for therapeutic drug monitoring.     

Early endocytotic steps in elicited macrophages: omega-shaped plasma membrane vesicles at their cell surface.

Fluid-phase and receptor-mediated endocytosis were studied in Freund's adjuvant elicited macrophages. These cells were found to bind and internalize significantly larger amounts of peroxidase-antiperoxidase (PAP) immune complex than resident macrophages. Similarly the rate of the fluid-phase uptake was higher in elicited cells. When studying the early steps of endocytotic processes, omega-shaped plasma membrane pits (d～90 nm) were found at the macrophage cell surface. Although occurring occasionally in resident cells, their number was highly increased after elicitation in 30% of the macrophage cell population. The different morphology of these cells coincided with a lower endocytotic activity and a very strong ecto Ca²⁺-ATPase reaction. The present findings indicate that the elicited macrophage population is heterogenous and consists of different subclasses.     

The Sandfish's Skin:Morphology,Chemistry and Reconstruction

The sandfish is a lizard having the remarkable ability to move in desert sand in a swimming-like fashion. The most out-standing adaptations to this mode of life are the low friction behaviour and the extensive abrasion resistance of the sandfish skin against sand, outperforming even steel. We investigated the topography, the composition and the mechanical properties of sandfish scales. These consist of glycosylated keratins with high amount of sulphur but no hard inorganic material, such as silicates or lime. Remarkably, atomic force microscopy shows an almost complete absence of attractive forces between the scale surface and a silicon tip, suggesting that this is responsible for the unusual tribological properties. The unusual glycosylation of the keratins was found to be absolutely necessary for the described phenomenon. The scales were dissolved and reconstituted on a polymer surface resulting in properties similar to the original scale. Thus, we provide a pathway towards exploitation of the reconstituted scale material for future engineering applications.     

Granulocyte-macrophage colony stimulating factor up-regulates CCR1 in human neutrophils

Neutrophils (polymorphonuclear leukocytes; PMN) are phagocytic cells instrumental in the clearance of infectious pathogens. Human PMN are commonly thought to respond primarily to chemokines from the CXC family. However, recent findings suggest that under specific cytokine activation conditions, PMN can also respond to some CC chemokines. In this study, the effect of GM-CSF, a well-characterized PMN priming and maturation factor, on CC-chemokine receptor (CCR) expression in PMN was investigated. Constitutive expression of CCR1 and CCR3 mRNA in PMN was detected by ribonuclease protection assay. Following incubation of PMN with GM-CSF (0.01-10 ng/ml; 6 h) CCR1 mRNA expression was rapidly (approximately 1 h) up-regulated. In contrast, no significant induction of CCR2, CCR3, CCR4, or CCR5 mRNA was observed. CCR1 protein was also up-regulated by GM-CSF stimulation. GM-CSF-induced up-regulation of CCR1 showed functional consequences because GM-CSF-treated PMN, but not control cells, responded to the CC chemokines macrophage inflammatory protein-1alpha, monocyte chemoattractant protein-3, and RANTES in assays of chemotactic migration and intracellular calcium mobilization. These results suggest that PMN activated by the proinflammatory cytokine GM-CSF can change their receptor expression pattern and become responsive to CC chemokines.