Online Detection of Ellipsoidal Bubbles by an Innovative Optical Approach

Bubble and droplet size distribution influence chemical processes markedly. In order to enable an in‐line analysis of these distributions, a new single‐sided endoscopic version of the Optical Multimode Online Probe (OMOP) was developed. The acquired images are analyzed to gain bubble size distributions (BSDs) and main diagonals. A specific workflow was developed to detect and analyze overlapping bubbles based on standard image processing techniques. It can handle overlapping bubbles of both circular and elliptical shapes. Results confirmed that the combination of OMOP and the image processing workflow leads to robust detection of bubbles from two‐dimensional images. The new single‐sided OMOP proved to be a suitable tool for the acquisition of a BSD at industrial scale within a reasonable computing time.     

Native casein micelles as nanocarriers for β‐carotene: pH‐and temperature‐induced opening of the micellar structure

To apply native casein micelles (CM) as nanocarriers for lipophilic substances in non‐ or low‐fat food products, they have to be conditioned before loading. In this study, an experimental set‐up for the production and loading of CM was developed. Microfiltration was used to separate CM from skimmed milk. To identify optimal loading conditions temperatures (2, 20, 40 °C), pH values (6.8 and 5.5) and holding times (5, 15, 30, 60 min) were varied. The release of calcium, phosphate and protein from the micellar phase as well as static light scattering and transmission electron microscopy showed that CM were optimally primed at 2 °C and a pH of 5.5 for 5 min. Therefore, loading with β‐carotene was performed under those conditions. After the back‐extraction of β‐carotene, the photometrical analyses revealed total recovery rates of >79% whereby 94% of it was associated with the native CM.     

The prebiotic,oligofructose‐enriched inulin modulates the faecal metabolite profile: An in vitro analysis

Scope: Health benefits of prebiotic administration have been judged mainly from the increased numbers of bifidobacteria and the enhanced production of short‐chain fatty acids in the colon. Only a few studies have focused on the capacity of prebiotics to decrease the proteolytic fermentation, which might contribute to health as well. Methods and results: The influence of the prebiotic oligofructose‐enriched inulin (OF‐IN) on the pattern of volatile organic compounds was characterized using an in vitro faecal model. Faecal slurries, obtained from healthy subjects, were anaerobically incubated at 37°C with and without different doses of OF‐IN (2.5, 5, 10, or 20 mg) and changes in the metabolite pattern and pH were evaluated. A total of 107 different volatile organic compounds were identified and classified according to their chemical classes. The concentration of esters and acids significantly increased with increasing doses of OF‐IN. Similar effects were observed for some aldehydes. To the contrary, OF‐IN dose‐dependently inhibited the formation of S‐compounds. Also, the generation of other protein fermentation metabolites such as phenolic compounds was inhibited in the presence of OF‐IN. Conclusion: Our results confirmed a clear dose‐dependent stimulation of saccharolytic fermentation. Importantly, a significant decrease in toxic protein fermentation metabolites such as sulphides attended these effects.     

The Proteoglycan Biglycan Modulates Platelet Adhesion and Thrombus Formation in a GPVI-Dependent Manner

Background: Vascular injury induces the exposure of subendothelial extracellular matrix (ECM) important to serve as substrate for platelets to adhere to the injured vessel wall to avoid massive blood loss. Different ECM proteins are known to initiate platelet adhesion and activation. In atherosclerotic mice, the small, leucine-rich proteoglycan biglycan is important for the regulation of thrombin activity via heparin cofactor II. However, nothing is known about the role of biglycan for hemostasis and thrombosis under nonatherosclerotic conditions. Methods: The role of biglycan for platelet adhesion and thrombus formation was investigated using a recombinant protein and biglycan knockout mice. Results: The present study identified biglycan as important ECM protein for the adhesion and activation of platelets, and the formation of three-dimensional thrombi under flow conditions. Platelet adhesion to immobilized biglycan induces the reorganization of the platelet cytoskeleton. Mechanistically, biglycan binds and activates the major collagen receptor glycoprotein (GP)VI, because reduced platelet adhesion to recombinant biglycan was observed when GPVI was blocked and enhanced tyrosine phosphorylation in a GPVI-dependent manner was observed when platelets were stimulated with biglycan. In vivo, the deficiency of biglycan resulted in reduced platelet adhesion to the injured carotid artery and prolonged bleeding times. Conclusions: Loss of biglycan in the vessel wall of mice but not in platelets led to reduced platelet adhesion at the injured carotid artery and prolonged bleeding times, suggesting a crucial role for biglycan as ECM protein that binds and activates platelets via GPVI upon vessel injury.     

How 14- and 18-month-olds know what others have experienced.

Fourteen- and 18-month-old infants observed an adult experiencing each of 2 objects (experienced objects) and then leaving the room; the infant then played with a 3rd object while the adult was gone (unexperienced object). The adult interacted with the 2 experienced objects in 1 of 3 ways: by (a) sharing them with the infant in an episode of joint engagement, (b) actively manipulating and inspecting them on his or her own as the infant watched (individual engagement), or (c) looking at them from a distance as the infant played with them (onlooking). As evidenced in a selection task, infants of both ages knew which objects had been experienced by the adult in the joint engagement condition, only the 18-month-olds knew this in the individual engagement condition, and infants at neither age knew this in the onlooking condition. These results suggest that infants are 1st able to determine what adults know (have experienced) on the basis of their direct, triadic engagements with them. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

High-resolution solid-state NMR studies on uniformly [13C,15N]-labeled ubiquitin

Understanding of the effects of intermolecular interactions, molecular dynamics, and sample preparation on high-resolution magic-angle spinning NMR data is currently limited. Using the example of a uniformly [13C,15N]-labeled sample of ubiquitin, we discuss solid-state NMR methods tailored to the construction of 3D molecular structure and study the influence of solid-phase protein preparation on solid-state NMR spectra. A comparative analysis of 13C', 13Calpha, and 13Cbeta resonance frequencies suggests that 13C chemical-shift variations are most likely to occur in protein regions that exhibit an enhanced degree of molecular mobility. Our results can be refined by additional solid-state NMR techniques and serve as a reference for ongoing efforts to characterize the structure and dynamics of (membrane) proteins, protein complexes, and other biomolecules by high-resolution solid-state NMR.     

The impact of pre‐ and/or probiotics on human colonic metabolism: Does it affect human health?

Since many years, the role of the colonic microbiota in maintaining the host's overall health and well-being has been recognized. Dietary modulation of the microbiota composition and activity has been achieved by the use of pre-, pro- and synbiotics. In this review, we will summarize the available evidence on the modification of bacterial metabolism by dietary intervention with pre-, pro- and synbiotics. Enhanced production of SCFA as a marker of increased saccharolytic fermentation is well documented in animal and in vitro studies. Decreased production of potentially toxic protein fermentation metabolites, such as sulfides, phenolic and indolic compounds, has been less frequently demonstrated. Besides, pre-, pro- and synbiotics also affect other metabolic pathways such as the deconjugation of secondary bile acids, bacterial enzyme activities and mineral absorption. Data from human studies are less conclusive. The emergence of new analytical techniques such as metabolite profiling has revealed new pathways affected by dietary intervention. However, an important challenge for current and future research is to relate changes in bacterial metabolism to concrete health benefits. Potential targets and expected benefits have been identified: reduced risk for the metabolic syndrome and prevention of colorectal cancer.     

The Membrane-Bound Lon Protease from Thermoplasma Displays Unfolding Activity

The membrane-bound Lon protease from Thermoplasma acidophilum (Ta Lon) was shown to unfold and degrade a fusion of the green fluorescent protein with calmodulin (GFP—CaM). Unfolding and degradation were ATP-dependent reactions and could be inhibited by calcium ions, which are known to stabilize calmodulin. Notably, an inverse fusion of the same proteins, i.e., CaM—GFP, as well as GFP or GFP-SsrA, was neither unfolded nor degraded. Thus, Ta Lon seems to unfold and degrade preferentially protein substrates with an extended unstructured C-terminus. A set of Ta Lon variants mutated in critical residues of the AAA⁺ domain, were tested for their respective ATPase and GFP—CaM unfolding activity. This analysis revealed that the rate of ATP hydrolysis correlated with the efficiency of the GFP—CaM unfolding activity. In summary, we show here that the membrane-bound Ta Lon protease displays an unfolding activity, which is correlated with the rate of ATP hydrolysis.     

Ovarian Accumulation of Nanoemulsions: Impact of Mice Age and Particle Size

Nanotechnology in the field of drug delivery comes with great benefits due to the unique physicochemical properties of newly developed nanocarriers. However, they may come as well with severe toxicological side effects because of unwanted accumulation in organs outside of their targeted site of actions. Several studies showed an unintended accumulation of various nanocarriers in female sex organs, especially in the ovaries. Some led to inflammation, fibrosis, or decreasing follicle numbers. However, none of these studies investigated ovarian accumulation in context to both reproductive aging and particle size. Besides the influences of particle size, the biodistribution profile may be altered as well by reproductive aging because of reduced capacities of the reticuloendothelial system (RES), changes in sex steroid hormone levels as well as altering ovarian stromal blood flow. This systematic investigation of the biodistribution of intravenously (i.v) injected nanoemulsions revealed significant dependencies on the two parameters particle size and age starting from juvenile prepubescent to senescent mice. Using fluorescent in vivo and ex vivo imaging, prepubescent mice showed nearly no accumulation of nanoemulsion in their uteri and ovaries, but high accumulations in the organs of the RES liver and spleen independently of the particle size. In fertile adult mice, the accumulation increased significantly in the ovaries with an increased particle size of the nanoemulsions by nearly doubling the portion of the average radiant efficiency (PARE) to ~10% of the total measured signal of all excised organs. With reproductive aging and hence loss of fertility in senescent mice, the accumulation decreased again to moderate levels, again independently of the particle size. In conclusion, the ovarian accumulation of these nanocarriers depended on both the age plus the particle size during maturity.