Comparison of antimicrobial resistance of Campylobacter jejuni and Campylobacter coli isolated from humans and chicken carcasses in Poland

Campylobacter-associated gastroenteritis remains an important cause of morbidity worldwide, and some evidence suggests that poultry is an important source of this foodborne infection in humans. This study was conducted to analyze the prevalence and genetic background of resistance of 149 Campylobacter jejuni and 54 Campylobacter coli strains isolated from broiler chicken carcasses and from stool samples of infected children in Poland from 2003 through 2005. Nearly all isolates were susceptible to macrolides and aminoglycosides. The highest resistance in both human and chicken strains was observed for ciprofloxacin (more than 40%), followed by ampicillin (13 to 21%), and tetracycline (8 to 29%). Resistance to ampicillin and tetracycline rose significantly between 2003 and 2005. Slight differences in resistance between human and chicken isolates indicate that although chicken meat is not the only source of Campylobacter infection in our population, it can be involved in the transmission of drug-resistant Campylobacter strains to humans.     

Ternary Biopolymer Based on Wheat Gluten,Whey Protein Concentrate and Montmorillonite

The aim of the research was to obtain biopolymers based on wheat gluten, whey protein concentrate (WPC) and montmorillonite (MON). Ternary biopolymers were formed as heat-induced gels and they were hardened by water evaporation. Adding 7 % of MON and 5 % WPC to gluten caused ca. four times higher values of storage modulus. Increased moduli values with adding MON and WPC to gluten were probably caused by reinforcing effect of MON, which decreased mobility of gluten chains and possible interactions between gluten and whey proteins by disulphide interchange. Increase in gluten protein concentration and addition of WPC and MON caused increase in viscosity measured by dissipation of ultrasound vibrations. Evaporation of water from the gels formed very hard material with high puncture force values. Obtained gels were very plastic and it was easy to form any type of shapes. They could be used to produce biodegradable pottery (e.g. flowerpots) with the mechanical properties similar to non-degradable clay products.     

The influence of protein–flavonoid interactions on protein digestibility in vitro and the antioxidant quality of breads enriched with onion skin

Different types of breads enriched with onion skin were studied. The objectives were twofold: to show and examine protein–phenolic interactions and to discuss results concerning phenolic content, antioxidant activity and protein digestibility in the light of in vitro bioaccessibility. Phenolic contents and antiradical abilities were linked with the level of onion skin supplement however, the amounts determined were significantly lower than expected. Fortification influenced protein digestibility (a reduction from 78.4% for control breads to 55% for breads with a 4% supplement). Electrophoretic and chromatographic studies showed the presence of indigestible protein–flavonoid complexes – with molecular weights about 25 kDa and 14.5 kDa; however, the reduction of free amino group levels and the increase in chromatogram areas suggest that flavonoids also bind to other bread proteins. The interaction of phenolics with proteins affects antioxidant efficacy and protein digestibility; thus, they have multiple effects on food quality and pro-health properties.     

The impact of glycated pea proteins on bacterial adhesion

Adhesion is one of the bacterial strategies indispensable for colonization of the small intestine. Food components reaching the small intestine, are not only digested and absorbed there, but may also influence the microorganisms colonizing the mentioned region. In this way, nutrients, particularly the ones the enzymatic degradation of which is hindered, acquire the ability to modify the adhesive potential of the autochthonic microorganisms. The glycated food proteins are noteworthy here for they often undergo relevant structural and functional alterations. Such proteins tend to display a lowered susceptibility to enzymatic degradation and thus may act as modulators of both metabolic activity and adhesive potential of bacteria adhered to the intestinal cells. For that reason, this study aimed at establishing the impact of the glycated pea proteins on adhesion of the bacteria from the genera: Lactobacillus, Enterococcus, and Escherichia, which are typical for the human small intestine.     

The Use of a Novel Ferulic Acid Esterase from Lactobacillus acidophilus K1 for the Release of Phenolic Acids from Brewer's Spent Grain

In this work, an extracellular ferulic acid esterase was produced in bioreactor cultivations of Lactobacillus acidophilus K1 strain. The enzyme was partially purified using ultrafiltration (10 kDa), dialysis (4–6 kDa) and Fast Protein Liquid Chromatography (Sepharose CM, Sephacryl S‐300). A considerable increment of enzyme activity (31‐fold) in the final preparation was achieved. Two distinct bands (approx. 21.5 kDa and 39 kDa) were obtained after SDS‐PAGE. A high similarity of the purified enzyme (LC‐MS/MS analysis) to tannase and ferulic acid esterase from Burkholderia ambifaria MEX‐5 was obtained. The optimal pH and temperature for the enzyme activity were 6.3 and 37°C, respectively. The enzyme preparation effectively released phenolic acids (mainly ferulic and p‐coumaric acid) from brewer's spent grain. This novel enzyme preparation can be used for the utilisation of a valuable and inexpensive by‐product of the brewing industry.     

The effect of catalyst and heat treatment on the properties of carbon–metal composites

Carbon gel and carbon–nickel–palladium doped gels (C–Ni–Pd) were prepared by carbonising resorcinol–formaldehyde (RF) hydrogel and resorcinol–formaldehyde–nickel–palladium (RF–Ni–Pd) hydrogels at 900 °C in a nitrogen atmosphere. RF and RF–Ni–Pd hydrogels were synthesized through sol–gel polycondensation followed by ambient drying. The aim of this study was the determination of the effect of heat treatment in air at 450 °C on the properties of C–Ni–Pd gels prepared using different Pd salts. In the present work, Ni was added as acetate whereas Pd was added as acetate (CA–Ni–Pd) and as chloride (CB–Ni–Pd). Samples were examined by scanning electron microscopy and X-ray diffraction. Surface area was characterized by N₂ adsorption at ?195.5 °C. Thermogravimetric analysis was carried out in order to determine the thermal characteristics of carbon gel and nickel–palladium composites in air atmosphere. CA–Ni–Pd composite had a higher activity and two-phase reaction compared to the CB–Ni–Pd composite. Further improvement of the electrolyte diffusion into the particles of nickel and palladium was obtained by oxidative thermal treatment. During this process a structural modification of the material took place, consequently leading to changes in the electrochemical properties of the composites.     

Effects of damming a large lowland river on chironomids and fish assessed with the (multiplicative partitioning of) true/Hill biodiversity measure

The impact of a large lowland temperate zone reservoir on chironomid and fish biodiversity was investigated in the same upstream (U) and downstream (D) sites on the same sampling occasions in spring and autumn of several post‐impoundment years. The true/Hill N1 diversity measure was used to construct diversity models of the impact, and partitioning of N1 to reveal the importance of ecological gradients. N1 is unique in being decomposable among multiple levels and easily comparable across ecosystems and animal groups. Chironomids were more diverse than fish in all community sets owing to their probably lower mobility, lower interspecific competition, opportunistic character and much shorter life spans than those of fish. Fish exerted consumption pressure on chironomids upstream by foraging mostly on benthic insects, but not downstream where they fed on microcrustaceans of reservoir origin or on epiphytic fauna (mainly Chironomidae). The reservoir impact on chironomids decreased their diversity in U and increased in D, while much the opposite was true in fish. In D in macroinvertebrates, the impact consisted in advancing over time intensification of seasonal development of submersed macrophytes, while in D in fish in a few species escaping from the reservoir after their populational explosions each year. Partitioning of diversity revealed that the spatial (upstream–downstream) gradient was the strongest factor of diversity change in chironomids as compared with season, and age of the impoundment. No gradient was dominant in fish. Comparisons of observed data with a null model testified to very strong intraspecific aggregation in both chironomids and fish. Copyright © 2010 John Wiley & Sons, Ltd.     

Physicochemical properties and quality parameters of herbhoneys

Herbhoney is a honey-like substance produced by bees fed on a saccharose-based food supplemented with herbal extracts or fruit juices. Having specific sensory characteristics (colour, aroma and taste), different from those of natural honeys, herbhoneys greatly extend the range of bee products. With the aim of improving the knowledge of herbhoneys of various origins, their chosen physicochemical and quality parameters were evaluated. It was found that the herbhoneys studied satisfied most of the requirements relative to natural honeys (water, hydroxymethylfurfural and saccharose contents, free acidity, and diastase number). Some of the samples showed an increased specific conductivity, characteristic of honeydew honeys, although the ash contents of herbhoneys were at a level typical of nectar honeys. The saccharose content of some herbhoneys exceeded the value allowed for most natural honeys. Mineral composition varied between the samples, being in most cases within the limits reported in this literature for natural honeys.     

Evaluation of the mechanical behavior of W7-X central support connections by means of semi-automated FE analysis

The stellarator Wendelstein 7-X is under construction at the Max-Planck-Institut für Plasmaphysik in Greifswald. Its superconducting coil system is fixed by a massive structure. During machine operation the coils exert high forces and moments against each other and the central support structure (CSS). Therefore, the detailed analysis of the coil to CSS connections, the so-called central support elements (CSE), is a critical item. The major details of the design have been frozen; nevertheless, there is still need for detailed analysis of the CSEs due to assembly issues, and later on for exploring operational limits of the machine. These analyses have to be performed quickly, reliably, and shall provide results in a standardized form to enable timely responses to the assembly team. Special numerical tools – finite element (FE) parametric models of CSEs – have been developed for the purpose of such analyses. In the models, the geometry, material properties, contact conditions, loads as well as results presentation are defined in a parametric way. The use of the developed models for the definition of the final weld parameters, bolt preloads, assessment of acceptable tolerances, and optimal positions of the CSE-wedges before welding is also discussed.