A Systematic Review of the Effects of Plant Compared with Animal Protein Sources on Features of Metabolic Syndrome.

Dietary protein may play an important role in the prevention of metabolic dysfunctions. However, the way in which the protein source affects these dysfunctions has not been clearly established. The aim of the current systematic review was to compare the impact of plant- and animal-sourced dietary proteins on several features of metabolic syndrome in humans. The PubMed database was searched for both chronic and acute interventional studies, as well as observational studies, in healthy humans or those with metabolic dysfunctions, in which the impact of animal and plant protein intake was compared while using the following variables: cholesterolemia and triglyceridemia, blood pressure, glucose homeostasis, and body composition. Based on data extraction, we observed that soy protein consumption (with isoflavones), but not soy protein alone (without isoflavones) or other plant proteins (pea and lupine proteins, wheat gluten), leads to a 3% greater decrease in both total and LDL cholesterol compared with animal-sourced protein ingestion, especially in individuals with high fasting cholesterol concentrations. This observation was made when animal proteins were provided as a whole diet rather than given supplementally. Some observational studies reported an inverse association between plant protein intake and systolic and diastolic blood pressure, but this was not confirmed by intervention studies. Moreover, plant protein (wheat gluten, soy protein) intake as part of a mixed meal resulted in a lower postprandial insulin response than did whey. This systematic review provides some evidence that the intake of soy protein associated with isoflavones may prevent the onset of risk factors associated with cardiovascular disease, i.e., hypercholesterolemia and hypertension, in humans. However, we were not able to draw any further conclusions from the present work on the positive effects of plant proteins relating to glucose homeostasis and body composition.

Interface roughness of plasma deposited polymer layers.

The interface roughness of adjacent films which were made by plasma polymerization of hexamethyldisiloxane were investigated. Multilayered structures were made by using different plasma conditions in alteration resulting in different mechanical properties within each layer. Scanning force microscopy on the face side of fractured pieces of the multilayer structures revealed a significant phase contrast between the layers. The direct visualization of the interface using the mechanical contrast between layers allowed the estimation of the interfacial roughness. We found that the interfaces between hexamethyldisiloxane films deposited at a radio frequency (RF) input power of 90 W in the presence of oxygen on top of films made by 48 W without oxygen resulted in an interface roughness of ≈10 nm. In the reverse case, a significantly lower interface roughness of ≈3 nm was determined. We attribute the increase of the interfacial roughness compared to the surface roughness being <1 nm to partial etching of the films by the subsequent deposition process. A key role in the appearance of higher interface roughness plays the RF-input power that determines the cross linking density and the hydrocarbon content in layers.

Atomic force microscopy studies on the nanomechanical properties of Saccharomyces cerevisiae.

In the past years atomic force microscopy (AFM) techniques have turned out to be a suitable and versatile tool for probing the physical properties of microbial cell surfaces. Besides interaction forces, nanomechanical properties can be obtained from force spectroscopic measurements. Analyzing the recorded force curves by applying appropriate models allows the extraction of cell mechanical parameters, e.g. the Young's modulus or the cellular spring constant. In the present work the nanomechanical properties of the baker's yeast Saccharomyces cerevisiae are extensively studied by force spectroscopy using an AFM. Single cells deform purely elastically so that a cellular spring constant can reliably be determined. It is presented, how this spring constant depends on the probing position on the cell, and how it depends on the extracellular osmotic conditions. Investigations aiming a statistically firm description of the nanomechanical behavior of the yeast cell population are conducted. Finally, the informative value of the cellular spring constant as a cell mechanical parameter is critically discussed.