The nature of transient protein complexes can range from a highly dynamic ensemble of orientations to a single well-defined state. This represents variation in the equilibrium between the encounter and final, functional state. The transient complex between plastocyanin (Pc) and cytochrome f (cytf) of the cyanobacterium Prochlorothrix hollandica was characterized by NMR spectroscopy. Intermolecular pseudocontact shifts and chemical shift perturbations were used as restraints in docking calculations to determine the structure of the wild-type Pc-cytf complex. The orientation of Pc is similar to orientations found in Pc-cytf complexes from other sources. Electrostatics seems to play a modest role in complex formation. A large variability in the ensemble of lowest energy structures indicates a dynamic nature of the complex. Two unusual hydrophobic patch residues in Pc have been mutated to the residues found in other plastocyanins (Y12G/P14L). The binding constants are similar for the complexes of cytf with wild-type Pc and mutant Pc, but the chemical shift perturbations are smaller for the complex with mutant Pc. Docking calculations for the Y12G/P14L Pc-cytf complex did not produce a converged ensemble of structures. Simulations of the dynamics were performed using the observed averaged NMR parameters as input. The results indicate a surprisingly large amplitude of mobility of Y12G/P14L Pc within the complex. It is concluded that the double mutation shifts the complex further from the well-defined toward the encounter state.

ObjectivesRegular walking is a critical target of physical activity (PA) promotion, and dog walking is a feasible PA intervention for a large segment of the population. The purpose of this paper was to review PA interventions that have involved canine interactions and to evaluate their effectiveness. A secondary aim of this review was to highlight the populations, settings, designs and intervention components that have been applied so as to inform future research.DesignSystematic review.Data sourcesWe carried out literature searches to August 2019 using six common databases.Eligibility criteriaStudies included published papers in peer-reviewed journals and grey literature (theses and dissertations) in the English language that included any PA behaviour change design (ie, randomised controlled trial, quasi-experimental) that focused on canine-related intervention. We grouped findings by population, setting, medium, research design and quality, theory and behaviour change techniques applied.ResultsThe initial search yielded 25 010 publications which were reduced to 13 independent studies of medium and high risks of bias after screening for eligibility criteria. The approaches to intervene on PA were varied and included loaner dogs, new dog owners and the promotion of walking among established dog owners. Findings were consistent in showing that canine-assisted interventions do increase PA (82% of the studies had changes favouring the canine-facilitated intervention). Exploratory subanalyses showed that specific study characteristics and methods may have moderated the effects. Compared with studies with longer follow-up periods, studies with shorter follow-up favoured behaviour changes of the canine intervention over the control condition.ConclusionCanine-based PA interventions appear effective, but future research should move beyond feasibility and proof of concept studies to increase rigour, quality and generalisability of findings.

Mushrooms Basidiomycota have long been appreciated for their taste, flavour, desirable aroma, texture, nutraceutical and medicinal attributes. Honey mushrooms (Armillaria mellea) are edible mushroom generally used in traditional oriental medicine. The aim of this study was to examine extracts from the fruiting bodies of these mushrooms. The content of the components with antioxidant properties, such as total phenols, total flavonoids, β-carotene, lycopene and β-glucans were determined by spectrophotometric methods. The results obtained showed that the water extracts contained higher levels of total phenols and total flavonoids (367.1 and 548.5 mg.dm−3 gallic acid equivalent — GAE, respectively) in comparison with methanol extracts (108.2 and 113.4 mg.dm−3 GAE, respectively). Very low contents of β-carotene and lycopene were determined in the methanol extract (0.756 mg.g−1 dry weight and 0.05 mg.g−1 dry weight, respectively). Methanol extracts from the fruiting bodies of Honey mushrooms (Armillaria mellea) inhibited the uptake activity of 2,2-diphenylpicrylhydrazyl (DPPH) free radicals by 45 %. The IC50 (mg of compound, that inhibit 50 % of DPPH radicals) of methanol extract was below 10 mg.cm−3 (6.448 mg.cm−3), suggesting a high antioxidant potential of fruiting bodies of the Honey mushrooms Armillaria mellea.

In this study we examined the dried fruiting bodies of Morchella esculenta, collected in the area of the coal and biomass based thermal power plant in Vojany from the nearby Bahoň marsh, in the Slovak Republic. The area is characterized by a high environmental burden, especially because of air pollutant emissions from the power plant operation. Twenty-three (23) chemical elements were found in the dried fruiting bodies after microwave-assisted sample preparation using an Inductively Coupled Plasma Mass Spectrophotometer ICP-MS AGILENT 7500c system. The mercury content was determined employing a special AMA 254 apparatus intended for the determination of Hg directly in dry powdered fruiting bodies without microwave digestion. The content of toxic elements expressed in mg.kg−1 DW (dry weight) were as follows: Hg 0.048—0.052 (RSD—Relative Standard Deviation = 4.80 %); Cd 4.543—6.169 (RSD = 3.35 %); Pb 0.261—0.291 (RSD = 2.67 %); As 0.455—0.469 (RSD = 5.79 %); Cr 1.585—1.616 (RSD = 2.33 %); and Ni 8.166—9.276 (RSD = 3.03 %). The contents of cadmium, nickel and mercury exceeded the hygiene limits, while the contents of arsenic and lead approached the hygiene limits. Due to the high levels of toxic elements, the fruiting bodies collected in the location are not suitable for culinary purposes. The mushroom Morchella esculenta acts as an accumulator of toxic elements from the environment in which it grows and can be considered as an indicator of environmental pollution.