Antioxidative activities and chemical characterization of polysaccharides extracted from the basidiomycete Schizophyllum commune

Antioxidant properties of hot water extract (HWE), hot water extracted polysaccharides (HWP) and hot alkali extracted polysaccharides (HWAE) were obtained from fruiting bodies of the wild basidiomycete Schizophyllum commune. All extracts contained both α- and β-glucans as determined by Megazyme β-glucan assay kit. Glucose was found by TLC and NMR to be the prevalent monosaccharide in all extracts. Total phenol contents were in descending order of HWP ≈ HWE > HWAE. Median effective concentrations (EC₅₀ values) of antioxidant activities were 8.3 ± 0.1, 6.9 ± 0.0 and 8.9 ± 0.1 mg/mL, and of the DPPH scavenging activity 0.8 ± 0.0, 0.6 ± 0.0 and 1.8 ± 0.0 mg/mL, for HWE, HWP and HWAE, respectively. EC₅₀ values of reducing power were 7.6 ± 0.1, 7.9 ± 0.0 and 12.5 ± 0.1 mg/mL, whereas those of the chelating abilities on ferrous ions were 3.1 ± 0.0, 4.6 ± 0.1 and 4.9 ± 0.1 mg/mL. The EC₅₀ values of the antioxidant activity, of the DPPH scavenging, and of the reducing power were correlated with total polysaccharide as well as with total phenol content. The antioxidant activities of all the extracts may be caused by both polysaccharides and polyphenols or by a complex of both.     

Trace element levels in raw milk from northern and southern regions of Croatia

A total of 157 raw milk samples were collected from tankers arriving at processing facilities from rural areas in northern and southern regions of Croatia during 2009 and 2010. Concentrations of As, Cd, Cu, Hg and Pb in the samples were analysed by graphite furnace-atomic absorption spectroscopy. Mean Pb concentrations in northern and southern regions were 58.7 and 36.2 μg l⁻¹, respectively, and both exceeded the maximum recommended level. Arsenic concentrations ranged from 1 to 283 μg l⁻¹ in the southern and to 1019 μg l⁻¹ in the northern regions. Mean Cd and Hg levels were: 1.76 and 1.59 in the northern and 3.4 and 7.1 μg l⁻¹ in the southern region. Significantly higher Cd and Hg levels were observed in the southern than in the northern region (p < 0.001, both). Similar mean Cu levels were found in both regions: 931.9 in the north and 848.4 μg l⁻¹ in the south. The results indicate that particular attention should be paid to Pb residues. In future studies, a greater number of milk samples and grass samples from pastures from different regions of Croatia should be controlled to confirm the absence of possible toxicological risks.     

Bioactive composition and antioxidant potential of different commonly consumed coffee brews affected by their preparation technique and milk addition

Coffee is one of the most popular beverages in the world, prepared and consumed in many different ways. Taste, aroma and composition of the coffee brew vary depending on the preparation method. Therefore, this study investigates the effect of different brewing methods on the polyphenol and methylxanthine composition and antioxidant capacity of thirteen different coffee brews. The content of total phenols and flavonoids was determined spectrophotometrically and the content of chlorogenic acid derivates (3-CQA, 4-CQA and 5-CQA) and caffeine using the high performance liquid chromatography (HPLC-PDA). Antioxidant capacity of coffee brews was evaluated by using the ABTS (2,2-azino-bis(3-ethylbenzthiazoline-6-sulfonic acid)) and FRAP (ferric-reducing antioxidant power) assays. Instant coffee brews showed the highest values in content of total phenols, chlorogenic acid derivates, caffeine and antioxidant capacity, which significantly decreased by milk addition. The antioxidant capacity of coffee brews was in compliance with the total phenol content and content of chlorogenic acid derivates.     

Impairment of cellular immunity in west Greenland sledge dogs (Canis familiaris) dietary exposed to polluted minke whale (Balaenoptera acutorostrata) blubber

Minke whale (Balaenoptera acutorostrata) blubber is rich in organohalogen contaminants, mercury, and n-3 fatty acids. In the present study we show that a daily intake of 50-200 g of minke whale blubber causes an impairment of the nonspecific and specific cellular immune system in the West Greenland sledge dog (Canis familiaris). Immune reactions were measured by mitogen (PHA, Con A) and antigen (KLH) intradermal testing, and as the study used exposure levels similar to those of Inuits and polar bears (Ursus maritimus), it is reasonable to infer that Inuits and polar bears suffer from similar decreased resistance to diseases. It is speculated that food sources are depleted by thinning sea ice due to climate change and that more research should assess the forecasted rise in additive immunopathy effects in polar bears. Additionally, our study suggests that the fatty acid composition may be of importance when investigating combined immunotoxic effects of contaminated food resources in future Inuit and polar bear studies.     

May Staphylococcus lugdunensis Be an Etiological Factor of Chronic Maxillary Sinuses Infection?

Staphylococcus lugdunensis is an opportunistic pathogen found in the healthy human skin microbiome bacterial community that is able to cause infections of diverse localization, manifestation, and course, including laryngological infections, such as necrotizing sinusitis. Chronic maxillary sinusitis is a disease present in up to one third of European and American populations, and its etiology is not fully described. Within this study, we aimed to characterize 18 S. lugdunensis strains recovered from maxillary sinuses and evaluate them as etiological agents of chronic disease. We performed MLST analysis, the complex analysis of both phenotypic and genetic virulence factors, antibiotic susceptibility profiles, and biofilm formation assay for the detection of biofilm-associated genes. Altogether, S. lugdunensis strains were clustered into eight different STs, and we demonstrated several virulence factors associated with the chronic disease. All tested strains were able to produce biofilm in vitro with numerous strains with a very strong ability, and overall, they were mostly susceptible to antibiotics, although we found resistance to fosfomycin, erythromycin, and clindamycin in several strains. We believe that further in-depth analysis of S. lugdunensis strains from different niches, including the nasal one, should be performed in the future in order to reduce infection rate and broaden the knowledge about this opportunistic pathogen that is gaining attention.     

Reinforcement Learning in the Multi-Robot Domain

This paper describes a formulation of reinforcement learning that enables learning in noisy, dynamic environments such as in the complex concurrent multi-robot learning domain. The methodology involves minimizing the learning space through the use of behaviors and conditions, and dealing with the credit assignment problem through shaped reinforcement in the form of heterogeneous reinforcement functions and progress estimators. We experimentally validate the approach on a group of four mobile robots learning a foraging task.     

The effect of music and lyrics on personality.

An experiment tested whether music can produce significant changes in the experience of one's own personality traits under laboratory conditions. Participants were 87 first-year undergraduates at a large Canadian university (58 women and 29 men; mean age = 18.3 years). After completing a set of questionnaires including the Big Five Inventory, they were divided into 3 groups: the music-and-lyrics group listened to a classical song while reading the English translation of lyrics, the music-only group listened to a classical song and followed along the text of lyrics in German, and the lyrics-only group listened to the English translation of the lyrics, while following its text as well. Participants were then readministered the Big Five Inventory within another set of questionnaires. The results show that music produced significant increases, and lyrics significant decreases, in the short-term self-reported experience of change of one's personality traits. (PsycINFO Database Record (c) 2011 APA, all rights reserved)