Comparative study of fungal cell disruption—scope and limitations of the methods

Simple and effective protocols of cell wall disruption were elaborated for tested fungal strains: Penicillium citrinum, Aspergillus fumigatus, Rhodotorula gracilis. Several techniques of cell wall disintegration were studied, including ultrasound disintegration, homogenization in bead mill, application of chemicals of various types, and osmotic shock. The release of proteins from fungal cells and the activity of a cytosolic enzyme, glucose-6-phosphate dehydrogenase, in the crude extracts were assayed to determine and compare the efficacy of each method. The presented studies allowed adjusting the particular method to a particular strain. The mechanical methods of disintegration appeared to be the most effective for the disintegration of yeast, R. gracilis, and filamentous fungi, A. fumigatus and P. citrinum. Ultrasonication and bead milling led to obtaining fungal cell-free extracts containing high concentrations of soluble proteins and active glucose-6-phosphate dehydrogenase systems

Solubility of palladium in picritic melts: 1. The effect of iron

In order to improve our understanding of HSE geochemistry, we evaluate the effect of Fe on the solubility of Pd in silicate melts. To date, experimentally determined Pd solubilities in silicate melt are only available for Fe-free anorthite-diopside eutectic compositions. Here we report experiments to study the solubility of Pd in a natural picritic melt as a function of pO2 at 1300 °C in a one atm furnace. Palladium concentrations in the run products were determined by laser-ablation-ICP-MS. Palladium increases from 1.07 ± 0.26 ppm at FMQ-2, to 306 ± 19 ppm at FMQ+6.6. At a relative pO2 of FMQ the slope in log Pd concentration vs. log pO2 space increases considerably, and Pd concentrations are elevated over those established for AnDi melt compositions. In the same pO2 range, ferric iron significantly increases relative to ferrous iron. Furthermore, at constant pO2 (FMQ+0.5) Pd concentrations significantly increase with increasing XFeO-total in the melt. Therefore, we consider ferric Fe to promote the formation of Pd2+ enhancing the solubility of Pd in the picrite melt significantly. The presence of FeO in the silicate melt has proven to be an important melt compositional parameter, and should be included and systematically investigated in future experimental studies, since most natural compositions have substantial FeO contents

Ultrasound-assisted chitosan-surfactant nanostructure assemblies: towards maintaining postharvest quality of tomatoes

A novel ultrasound-assisted chitosan–surfactant nanostructure assembly was developed to allow better delivery of chitosan particles into intact fruit tissues for extension of postharvest life. Three solutions of 1 % chitosan–surfactant nanostructure assembly with micelle sizes of 400, 600 and 800 nm were prepared and applied as an edible coating on tomatoes. The fruits were stored at 15 ± 2 °C and 70–80 % relative humidity for 20 days. The indicators of tomato ripening, which included loss of firmness, decline of titratable acidity, decline of chlorophyll content and increase in soluble solid content, were delayed in the treated fruits in comparison to the control (p  0.05)

The use of spatial intensity distribution analysis to examine G protein-coupled receptor oligomerization

Spatial Intensity Distribution Analysis (SpIDA) is a new approach for detecting protein oligomerization states that can be applied not only to live cells but also fixed cells and native tissue. This approach is based on the generation of pixel-integrated fluorescence intensity histograms from laser scanning fluorescence microscopy images. These histograms are then fit with super-Poissonian distribution functions to obtain density maps and quantal brightness values of the fluorophore that are used to determine the proportions of monomer and dimers/oligomers of the fluorophore-tagged protein. In this chapter we describe SpIDA and highlight its advantages compared to other biochemical or biophysical approaches. We provide guidelines that should be useful to readers who wish to perform SpIDA measurements and describe the application of SpIDA as a post-acquisition imaging histogram analysis software tool to investigate the oligomeric state of G protein-coupled receptors (GPCRs) at the surface of mammalian cells in order to define the steady-state proportion of monomeric and dimeric/oligomeric forms and how this may be regulated by cellular challenges such as ligand treatment