Comparison of the internalization efficiency of LDL and transferrin receptors on L2C guinea pig lymphocytes

AbstractWe demonstrate that L2C lymphocytes have about 10-times more receptors for transferrin (TO than healthy lymphocytes, as has been shown in the case of LDL receptors. The dissociation constant is the same in the two cell types (about 4 × 10−7 M). In contrast to LDL, Tf enters L2C lymphocytes with very rapid kinetics. It is shown by cross-reaction that each receptor is internalized independently of the other

A comparison of the ability of PLFA and 16S rRNA gene metabarcoding to resolve soil community change and predict ecosystem functions

Soil bacterial community structure has traditionally been measured using phospholipid fatty acid (PLFA) profiling. However, with the development of high-throughput sequencing technologies and metabarcoding techniques, more studies are now using 16S rRNA gene metabarcoding to measure bacterial community structure. Metabarcoding provides a much greater level of detail than PLFA profiling does, but it remains unclear whether or not the two techniques have a similar ability to answer many of the common questions asked by ecologists. We test the relative ability of the two techniques to quantify differences in bacterial community structure among five land uses (natural and planted forest, unimproved and improved grasslands, and vineyards), and to predict ecosystem functions. We also test whether PLFA- and metabarcoding-based metrics indicative of microbial growth strategies are correlated to each other. We show that both techniques showed broadly similar patterns of bacterial community composition change with land use and a remarkably similar ability to predict a wide range of ecosystem functions (carbon and nutrient cycling, and responses to drought). However, they were also complementary, as each showed different strengths in discriminating land uses and predicting ecosystem functions. PLFA metrics (i.e. the gram-positive:gram-negative ratio and fungal:bacterial ratio) were strongly correlated with the equivalent 16S rRNA gene metabarcoding metrics (i.e. the gram-positive:gram-negative and oligotrophic:copiotrophic ratios), although PLFA metrics were less well correlated with the Proteobacteria:Acidobacteria ratio. For many ecological questions the two techniques thus give broadly comparable results, providing confidence in the ability of both techniques to quantify meaningful changes in bacterial communities

A comprehensive multiscale moisture transport analysis: From porous reference silicates to cement-based materials

International audienceNatural and manufactured disordered systems are ubiquitous and often involve hierarchical structures. This structural organization optimizes defined physical properties at several scales from molecular to representative volumes where the usual homogenization approach becomes efficient. For studying a particular physical property on these systems it is thus required to use a general method of analysis based on the joint application of complementary techniques covering the whole set of time-and length-scales. Here we review a comprehensive multiscale method presented for analyzing the three-dimensional moisture transport in hierarchical porous media such as synthesized reference silicates and cement-based materials. Several techniques (NMR spectroscopy, relaxometry, diffusometry, X-ray micro-tomography, conductivityaEuro broken vertical bar) have been used to evidence the interplay between the different scales involved in this transport process. This method allows answering the general opened questions concerning the scale dependence of such a moisture transport in cement-based materials. We outline the main results of the multiscale techniques applied on reference porous silicates allowing separating the impact of geometry, hydric state and wettability on the moisture transport. Based on this approach, we prove that this transport at micro- and meso-scale is determinant to modify the moisture at macro-scale during setting or for hardened cement-based materials