Simultaneous detection of spin-coupled and decoupled QA– EPR-signals in Photosystem II complexes isolated with isoelectric focusing

The Photosystem II multisubunit protein complex can be extracted from thylakoid membranes with non-ionic detergents and subjected to various spectroscopical and biochemical investigations. This paper shows that after extraction with dodecyl--D-maltoside, several Photosystem II complexes could be resolved by isoelectric focusing. Structurally, the various Photosystem II complexes differed from each other in polypeptide composition, especially with regard to the chlorophyll a/b-binding proteins, which gave rise to differing isoelectric points. Functionally, the various Photosystem II complexes differed from each other on the acceptor side, as judged by acceptor side-dependent electron transfer and electron paramagnetic resonance (EPR). The Q_A ^- Fe2+-signal (g = 1.84), arising from Q_A ^- spin-coupled to the acceptor-side iron, and a radical signal arising from decoupled Q_A ^- (g = 2.0045) could be detected simultaneously in some of the Photosystem II complexes, and the amount of each of the two signals were inversely related. The results are discussed in relation to previously known heterogeneities in Photosystem II.     

The genetic background of antibiotic resistance among clinical uropathogenic Escherichia coli strains

Molecular Biology Reports - The spreading mechanisms of antibiotic resistance are related to many bacterial and environment factors. The overuse of antibiotics is leading to an unceasing emergence...     

Nested PCR for the detection of Aspergillus species in maxillary sinus samples of patients with chronic sinusitis

Background

Fungal rhinosinusitis has become an increasingly recognized disease, being Aspergillus species responsible for most of the cases. Its diagnosis is quite difficult because of the non-specific symptoms and low sensitivity of the current diagnostic methods.

Hepatoprotective,Hypoglycemic, and Hypolipidemic Effect of Chokeberry Pomace on Polish Merino Lambs*

To properly understand the biological effect of polyphenol compounds, it should not be assumed that they are generally bioavailable and are reaching tissues as expected. It is important to fully understand how polyphenol compounds are absorbed, metabolized, and finally eliminated from the organism. Most polyphenol compounds occur in the forms that cannot be absorbed in their primary form. Sheep make compounds bioavailable due to their unique digestive system properties. Despite this, several species of ruminants likely to serve as an experimental model were considered. However, due to the high costs for cattle and low popularity in the region of goats, sheep were selected as the experimental model. In the study, 24 Polish Merino lambs were randomly divided into a control and two experimental groups. The experimental groups were administered diets with the addition of 150 or 300?g of chokeberry pomace per each kg of complete feed mixture. Phenolics present in the chokeberry pomace were found to modulate biochemical blood parameters, resulting in hypoglycemic and hypolipidemic effects. Finally, the increase in total phenolics in the serum and liver of lambs induced a health-promoting effect on liver metabolic profile parameters.     

Explaining variability in the production of seed and allergenic pollen by invasive <Emphasis Type="Italic">Ambrosia artemisiifolia</Emphasis> across Europe

To better manage invasive populations, it is vital to understand the environmental drivers underlying spatial variation in demographic performance of invasive individuals and populations. The invasive common ragweed, Ambrosia artemisiifolia, has severe adverse effects on agriculture and human health, due to its vast production of seeds and allergenic pollen. Here, we identify the scale and nature of environmental factors driving individual performance of A. artemisiifolia, and assess their relative importance. We studied 39 populations across the European continent, covering different climatic and habitat conditions. We found that plant size is the most important determinant in variation of per-capita seed and pollen production. Using plant volume as a measure of individual performance, we found that the local environment (i.e. the site) is far more influential for plant volume (explaining 25% of all spatial variation) than geographic position (regional level; 8%) or the neighbouring vegetation (at the plot level; 4%). An overall model including environmental factors at all scales performed better (27%), including the weather (bigger plants in warm and wet conditions), soil type (smaller plants on soils with more sand), and highlighting the negative effects of altitude, neighbouring vegetation and bare soil. Pollen and seed densities varied more than 200-fold between sites, with highest estimates in Croatia, Romania and Hungary. Pollen densities were highest on arable fields, while highest seed densities were found along infrastructure, both significantly higher than on ruderal sites. We discuss implications of these findings for the spatial scale of management interventions against A. artemisiifolia.     

Study of the Serum Copper Levels in Patients with Major Depressive Disorder

Copper may be involved in the pathophysiology of depression. Clinical data on this issue are very limited and not conclusive. The purpose of the study was to determine the copper concentration in the serum of patients with major depressive disorder and to discuss its potential clinical usefulness as a biomarker of the disease. A case–control clinical study included 69 patients with current depressive episode, 45 patients in remission and 50 healthy volunteers. Cu concentration was measured by electrothermal atomic absorption spectrometry (ETAAS). The mean serum copper level in depressed patients was slightly lower (by 11 %; not statistically significant) than in the control group. Furthermore, there was no significant difference in Cu²⁺ concentration between depressive episode and remission, nor between remission and control group. In the remission group were observed significant correlations between copper levels and the average number of relapses over the past years or time of remission. There was no correlation between serum copper and severity of depression, as measured by HDRS and MADRS. The obtained results showed no significant differences between the copper concentration in the blood serum of patients (both with current depressive episode and in remission) and healthy volunteers, as well as the lack of correlations between the copper level in the active stage of the disease and clinical features of the population. Our study is the first conducted on such a large population of patients, so the results may be particularly important and reliable source of knowledge about the potential role of copper in depression.     

Shape-memory effects in biopolymer networks with collagen-like transient nodes

In this article we study shape-memory behavior of hydrogels, formed by biodegradable and biocompatible recombinant telechelic polypeptides, with collagen-like end blocks and a random coil-like middle block. The programmed shape of these hydrogels was achieved by chemical cross-linking of lysine residues present in the random coil. This led to soft networks, which can be stretched up to 200% and "pinned" in a temporary shape by lowering the temperature and allowing the collagen-like end blocks to assemble into physical nodes. The deformed shape of the hydrogel can be maintained, at room temperature, for several days, or relaxed within a few minutes upon heating to 50 °C or higher. The presented hydrogels could return to their programmed shape even after several thermomechanical cycles, indicating that they remember the programmed shape. The kinetics of shape recovery at different temperatures was studied in more detail and analyzed using a mechanical model composed of two springs and a dashpot.