Targeting the Surface of the Protein 14-3-3 by Ultrasmall (1.5 nm) Gold Nanoparticles Carrying the Specific Peptide CRaf

The surface of ultrasmall gold nanoparticles with an average diameter of 1.55 nm was conjugated with a 14-3-3 protein-binding peptide derived from CRaf. Each particle carries 18 CRaf peptides, leading to an overall stoichiometry of Au(115)Craf(18). The binding to the protein 14-3-3 was probed by isothermal titration calorimetry (ITC) and fluorescence polarization spectroscopy (FP). The dissociation constant (K_D) was measured as 5.0 μM by ITC and 0.9 μM by FP, which was close to the affinity of dissolved CRaf to 14-3-3σ. In contrast to dissolved CRaf, which alone did not enter HeLa cells, CRAF-conjugated gold nanoparticles were well taken up by HeLa cells, opening the opportunity to target the protein inside a cell.     

Einstellung einer künstlichen Ernährung und kritische Anfragen an die Rechtsprechung

Ohne Zusammenfassung

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Characterization of fat replacers

Effects of commercial fat replacers on rheological properties of emulsions have been studied under a second-order design. The corresponding functions of regression have been calculated to describe the measured effects mathematically. On the basis of a figured three-dimensional plan of response, combinations of variables (fat, fat replacer, water) could be determined showing a similar consistency to the corresponding full-fat foodstuff.

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Zur Charakterisierung von Fettaustauschern

Zusammenfassung Die Wirkung kommerzieller Fettaustauscher auf rheologische Eigenschaften von O/W-Emulsionen wurde unter Nutzung eines quadratischen Prozeßmodells untersucht und die zugehörigen Schätzfunktionen für die mathematische Beschreibung der Effekte ermittelt. Aus der dreidimensionalen Darstellung der Antwortflächen ergab sich eine einfache Möglichkeit zur Bestimmung von Variablenkombinationen (Fett, Fettaustauscher und Wasser), um Konsistenzparameter vergleichbarer Vollfettprodukte zu simulieren.

     

Jumbo squid (Dosidicus gigas) mantle muscle gelled-emulsified type product: formulation, processing and physicochemical characteristics

Jumbo squid ( Dosidicus gigas ), an abundant species in the Gulf of California, can have a great potential for production of gelled-emulsified type products. Thus, formulation, processing and physicochemical characteristics of frankfurter-type product from jumbo squid mantle muscle (JSF) was achieved. JSF were vacuum-packed and stored at 2–4 °C. Samples were analysed for physicochemical (colour, texture, TBARS, peroxide value, folding test, pH, and water content and holding capacity) and microbial changes at regular intervals during storage for up to 27 days. The sensory quality of the product was also evaluated. Shear force, cohesiveness and colour (hue angle and total colour difference) were the most affected ( P  <   0.05) parameters at day 27, changes most probably because of microbial growth as total aerobic counts increased to >2.7 × 10⁵ CFU g⁻¹ (day 21). Product showed acceptability. Results suggest a stable gelled-emulsified type product can be developed from jumbo squid mantle muscle opening a range of possibilities for product development.     

Accumulation of silver nanoparticles by cultured primary brain astrocytes

Silver nanoparticles (AgNP) are components of various food industry products and are frequently used for medical equipment and materials. Although such particles enter the vertebrate brain, little is known on their biocompatibility for brain cells. To study the consequences of an AgNP exposure of brain cells we have treated astrocyte-rich primary cultures with polyvinylpyrrolidone (PVP)-coated AgNP. The incubation of cultured astrocytes with micromolar concentrations of AgNP for up to 24 h resulted in a time- and concentration-dependent accumulation of silver, but did not compromise the cell viability nor lower the cellular glutathione content. In contrast, the incubation of astrocytes for 4 h with identical amounts of silver as AgNO(3) already severely compromised the cell viability and completely deprived the cells of glutathione. The accumulation of AgNP by astrocytes was proportional to the concentration of AgNP applied and significantly lowered by about 30% in the presence of the endocytosis inhibitors chloroquine or amiloride. Incubation at 4?°C reduced the accumulation of AgNP by 80% compared to the values obtained for cells that had been exposed to AgNP at 37?°C. These data demonstrate that viable cultured brain astrocytes efficiently accumulate PVP-coated AgNP in a temperature-dependent process that most likely involves endocytotic pathways.