Prevalence of Campylobacter spp. in poultry and poultry meat in Germany

Of 509 samples from poultry flocks, 209 isolates (41.1%) were Campylobacter positive. The number of positive cases in broiler carcasses was 45.9%. Of 52 pheasants investigated, 25.9% were Campylobacter positive. Campylobacter jejuni was isolated from 86 (42.0%) poultry flock samples, 47 (43%) broiler samples and 15 (28%) wild pheasant samples. C. coli was found at a rate of 1.2% in poultry flocks, 13% in broilers and 21% in pheasants.     

How to bring orphan genes into functional families

In the framework of the B1 Consortium of the EUROFAN-1 project, we set up a series of simple phenotypic tests that can be performed on a large number of strains at a time. This methodological approach was intended to help assign functions of putative genes coding for unknown proteins to several specific aspects of cell biology. The tests were chosen to study phenotypes which should be affected by numerous genes. In this report, we examined the sensitivity/resistance or the adaptation of the cell to physical or chemical stresses (thermotolerance, osmotolerance and ethanol sensitivity), the effects of the alteration of the level of protein phosphorylation (sensitivity or resistance to compounds affecting the activity of protein kinases or phosphatases) and the effects of compounds interfering with synthesis of nucleic acids or proteins. Deletions in 66 genes of unknown function have been tested in 21 different conditions. In many deletant strains, phenotypes were observed and, for the most promising candidates, tetrad analysis was performed in order to verify co-segregation of the deletion marker with the phenotype.     

Two-dimensional analysis of proteins secreted by Saccharomyces cerevisiae regenerating protoplasts: a novel approach to study the cell wall

Protoplasts of Saccharomyces cerevisiae incubated in regenerating conditions secrete cell wall components in order to allow the biosynthesis of this structure. During the first hours of incubation, many of these are not retained in the forming cell wall but remain in the medium. We have developed a method for collecting the secreted proteins and have analysed these by two-dimensional electrophoresis to obtain a reference map of putative cell wall proteins. Several proteins were identified by microsequencing or immunoblotting; namely, cell wall hydrolytic enzymes, heat shock proteins, glycolytic enzymes and others. Some beta-1,3- and beta-1, 6-glucosylation was detected in the proteins secreted by regenerating protoplasts.     

Lactobacilli isolated from chicken intestines: potential use as probiotics

Lactobacillus strains were tested for their in vitro probiotic properties. Cell surface hydrophobicity was found to be very high for Lactobacillus fermentum subsp. cellobiosus and Salmonella Gallinarum; high values could indicate a greater ability to adhere to epithelial cells. Studies on Lactobacillus animalis indicated relative cell surface hydrophobicities smaller than those of L. fermentum subsp. cellobiosus and L. fermentum. L. animalis and Enterococcus faecalis were able to coaggregate with L. fermentum subsp. cellobiosus and L. fermentum, respectively, but not with Salmonella Gallinarum. After mixed-culture studies for determining suitable growth behavior, the pair of strains L. animalis plus L. fermentum subsp. cellobiosus was selected for an attempted challenge against Salmonella Gallinarum. Double and triple mixed-culture studies indicated that selected lactobacillus strains were able to retain their beneficial characteristics in the presence of Salmonella Gallinarum such as presence of lectins, production of antimicrobial compounds, and ability to grow and compete. The selected microorganisms can be considered as potential ingredients for a chicken probiotic feed formulation intended to control salmonellosis and also improve poultry sanitation.     

Objective measurement of veal color for classification purposes

2300 veal calves were used to compare the ability of chromameters to measure the veal meat color on-line and to develop a relationship between instrumental and visual assessments to predict the color score according to the EC-system of classification. The meat color was assessed subjectively by 3 trained judges and objectively by 2 chromameters CR300 and CR310, 45 min post mortem on the Rectus abdominis, on the external side, skin having been removed. R(2) values reached 0.70 for the CR300 and 0.75 for the CR310. The equations of prediction classified correctly up to 87% of carcasses. These data indicate that chromameters (Minolta CR310 and CR300) can be used on-line to measure objectively veal meat color at the end of the slaughterline.     

A Review on the Radioprotective Activity of organogermanium and Organosilicon Compounds

The present review describes the work carried out during the last 20 years in the field of the radioprotective activity and toxicity of several classes of organosilicon and organogermanium compounds (i.e. metallathiazolidines, metalladithioacetals, metallatranes and germathianes).     

Emulsion-based fluorosensors for potassium featuring improved stability and signal change

A novel kind of potassium optode is presented which is based on the use of lipophilic droplets containing valinomycin and entrapped in a structured hydrogel. A positively charged solvatochromic dye located near the surface of the droplets responds to the valinomycin-assisted extraction of potassium from the sample by dramatic decrease of fluorescence intensity. The dynamic range is from 5 to 100 mM potassium, with negligible cross sensitivity to ionic strength. Cross sensitivity to pH is negligible too in the pH range from 6.5 to 7.3. The effect of interfering lipophilic anions is discussed. Response times within the dynamic range are less than 3 min on going from low to high potassium ion concentrations but about 10 min in the reverse direction. Response is fully reversible with only small drifts in baseline. The measurement uncertainty of determining 5 mM potassium is better than 0.2 mM.     

Effect of ionic strength on the behavior of amperometric enzyme electrodes mediated by redox hydrogels

The electron-transfer behavior of electroactive hydrogels formed by cross-linking ferrocene poly(allylamine) (Fc-PAA) and glucose oxidase is investigated as a function of electrolyte ionic strength using several techniques. Cyclic voltammetry and electrochemical impedance spectroscopy show that the quantity cD(e)(1/2) increases with electrolyte concentration. Enhancement of enzyme catalysis for the oxidation of glucose mediated by Fc-PAA is also apparent at higher KNO(3) concentration. The electroactive redox center concentration, c, and the diffusion coefficient due to electron hopping in the gel, D(e), are independently measured by chronoamperometry at ultramicroelectrodes. Larger electrolyte ionic strength induces an increase in electroactive redox center concentration while D(e) slightly decreases. These results are rationalized in terms of the electrostatic interactions within the redox gel backbone due to water and ion exchange with the external electrolyte, producing swelling and shrinking of the hydrogel.     

Role of mass accumulation and viscoelastic film properties for the response of acoustic-wave-based chemical sensors

The sensitivity of acoustic-wave microsensors coated with a viscoelastic film to mass changes and film modulus (changes) is examined. The study analyzes the acoustic load at the interface between the acoustic device and the coating. The acoustic load carries information about surface mass and film modulus; its determination has no restrictions in film thickness. Two regimes of film behavior can be distinguished: the gravimetric regime, where the sensor response is mainly mass sensitive, and the nongravimetric regime, where viscoelasticity gains influence on the sensor response. We develop a method, which allows the assignment of the sensor signal to a gravimetric or a nongravimetric response. The critical value can be determined from oscillator measurements. The related limits for the coating thickness are not the same for the coating procedure and mass accumulation during chemical sensing. As an example, we present results from a 10 MHz quartz crystal resonator.