SummaryAnaplasma species are obligate intracellular rickettsial pathogens transmitted by ticks with an impact on human and animal health. Anaplasma ovis infects sheep and goats in many regions of the world, and it can be diagnosed by different methods like Giemsa staining, PCR or competitive ELISA. In this study, a PCR based on the gene coding for major surface protein 4 (MSP-4) was used to examine field samples collected from sheep in different countries. Altogether, 1161 blood samples from Turkey (n = 830), Iraq (n = 195), Sudan (n = 96) and Portugal (n = 40) were examined, of which 31.4%, 66.6% 41.6% and 82.5%, respectively, were positive. This indicates high prevalence of A. ovis in the countries under investigation, and it can be assumed that the situation in other areas of the world might be similar. Thus, A. ovis should be considered as an important constraint of livestock production, and further efforts are needed to better understand the epidemiology and to implement suitable control measures.

We present a particle-sorting device based on the opposition of dielectrophoretic forces. The forces are generated by an array of electrode chambers located in both sidewalls of a main flow channel. Particles with different dielectric response perceive different force magnitudes and are therefore continuously focused to different streamlines in the flow channel. We relate the particles' dielectric response to their output position in the downstream channel. We demonstrate the performance of the device by separating a mixed yeast cell population into pure fractions of viable and nonviable cells. Finally, we use the device to enrich red blood cells infected with Babesia bovis, a major pathogen in cattle and simultaneously confirm the hypothesis that infection with B. bovis causes significant changes in the dielectric response of red blood cells.

An optical fiber sensing system, for monitoring oxygen aiming in vivo nuclear magnetic resonance (NMR) applications is presented. Oxygen detection is based on the dynamic quenching of the fluorescence of a ruthenium complex trapped in the porous structure of a sol-gel silica film. Oxygen concentration is determined by phase-modulation fluorometry. Preliminary results concerning the characterization of doped sol-gel thin films deposited by dip coating in glass slides and in optical fiber probes are presented. Four different probe configurations are tested and compared. Best results are obtained with a fiber taper configuration which shows reproducibility and best excitation efficiency. This structure is fully characterized and some considerations regarding optimal fiber optical sensing probes for O 2 detection are addressed.

BackgroundNanotechnology has the potential to provide agriculture with new tools that may be used in the rapid detection and molecular treatment of diseases and enhancement of plant ability to absorb nutrients, among others. Data on nanoparticle toxicity in plants is largely heterogeneous with a diversity of physicochemical parameters reported, which difficult generalizations. Here a cell biology approach was used to evaluate the impact of Quantum Dots (QDs) nanocrystals on plant cells, including their effect on cell growth, cell viability, oxidative stress and ROS accumulation, besides their cytomobility.ResultsA plant cell suspension culture of Medicago sativa was settled for the assessment of the impact of the addition of mercaptopropanoic acid coated CdSe/ZnS QDs. Cell growth was significantly reduced when 100 mM of mercaptopropanoic acid -QDs was added during the exponential growth phase, with less than 50% of the cells viable 72 hours after mercaptopropanoic acid -QDs addition. They were up taken by Medicago sativa cells and accumulated in the cytoplasm and nucleus as revealed by optical thin confocal imaging. As part of the cellular response to internalization, Medicago sativa cells were found to increase the production of Reactive Oxygen Species (ROS) in a dose and time dependent manner. Using the fluorescent dye H2DCFDA it was observable that mercaptopropanoic acid-QDs concentrations between 5-180 nM led to a progressive and linear increase of ROS accumulation.ConclusionsOur results showed that the extent of mercaptopropanoic acid coated CdSe/ZnS QDs cytotoxicity in plant cells is dependent upon a number of factors including QDs properties, dose and the environmental conditions of administration and that, for Medicago sativa cells, a safe range of 1-5 nM should not be exceeded for biological applications.