Impact of Stolbur Phytoplasmas on Potato Tuber Texture and Sugar Content of Selected Potato Cultivars

Potato stolbur is a phytoplasmal disease that seriously affects yield and tuber quality in South Eastern Europe, Russia and the Mediterranean areas. In 2007 and 2008, field experiments were carried out to determine stolbur resistance of processing potato cultivars at Sannicolau Mare (Romania) by determining consistency and concentration of reducing sugars (fructose and glucose), sucrose and phytoplasmas in potato tubers. In both years, non-symptomatic potato tubers showed sucrose levels in the range of 3,000 mg kg⁻¹ fresh weight (FW). In contrast, sucrose concentrations were up to 11,820 mg kg⁻¹ FW in 2007 and 19,560 mg kg⁻¹ FW in 2008 in tubers showing severe symptoms. These high values severely affect suitability of tubers for processing as sucrose serves as substrate for the formation of reducing sugars that are the limiting factor in fried potato production for Maillard-related discolouration. The cultivars examined differed considerably in susceptibility to stolbur disease. Whereas cvs. ‘Courage’ and ‘Lady Rosetta’ showed high numbers of diseased tubers and high sucrose concentrations, ‘Lady Claire’ had a lower incidence of symptomatic tubers and lower sucrose concentrations. However, fully resistant cultivars were not observed. Across all cultivars examined, phytoplasmal concentration was significantly higher in symptomatic tubers than in non-symptomatic ones.     

Effect of biotin supplementation on the vLa4 of thoroughbred horses

Thoroughbred horses in racing condition were supplemented twice daily with 25 mg biotin (biotin group), while control horses received an equivalent amount of maltodextrose as a placebo (placebo group). Changes of v_fLa4 (running speed necessary for producing a lactate concentration of 4 mmol/l in the blood) were determined with an incremental step test within three days and after two, three and four months after the beginning of supplementation. The mean v_fLa4 of both the biotin and the placebo groups (5 horses each) did not change significantly within three days of supplementation, but the mean plasma biotin concentration increased in the biotin group from 1.3±0.4 to 47±22 nmol/l (p<0.01), while remaining below 3 nmol/1 in the placebo group. There was no significantly different development of the v_fLa4 between groups over four months of supplementation. But, while the mean v_fLa4 of Thoroughbreds supplemented with biotin over this period of time did not show any changes, the v_fLa4 of the placebo group horses showed a tendency to decrease. In the biotin group, the mean plasma biotin levels varied between 38 and 64 nmol/l over the four months, while the biotin concentration of the placebo group never exceeded 3 nmol/1.     

CD4(+) T-cell responses against the VP1-unique region in individuals with recent and persistent parvovirus B19 infection

To date cellular immune responses against parvovirus B19 (B19) have not been studied extensively. The aim of this study was to examine the T-cell response against the VP1-unique region as the immunodominant part of the viral structural protein VP1 in individuals with different courses of B19 infection. Therefore, a group of 13 parvovirus-positive probands was separated into subgroups characterized for recent or acute, past or persistent infection by means of the presence of specific immunoglobulin (Ig)M and IgG isotypes and of viral DNA in blood and tissue. Transiently transfected B-cells expressing VP1-unique region were used in ELISpot assays to investigate T-cell responses directed against the VP1-unique region in peripheral blood mononuclear cells (PBMC) of individual donors. Significant numbers of interferon-gamma (IFN-gamma) secreting lymphocytes were detectable in PBMC of all individuals with recent, acute or persistent B19 infection, but not in PBMC of donors with past B19 infection and seronegative individuals. A more detailed analysis of IFN-gamma producing cells by intracellular cytokine staining by flow cytometry revealed, that CD4(+) T cells but not CD8(+) cytotoxic lymphocytes (CTL) were the major subpopulation of IFN-gamma producing cells. These data strongly suggest the need of virus protein production for the maintenance of VP1-unique region-specific CD4(+) T-helper cell responses in B19-infected individuals.     

Antibody response after immunization with a Salmonella Typhimurium live vaccine in dependence on the way of application

In Germany now, the recognition of Salmonella infections in pig herds is based on three different commercial tests detecting antibodies against Salmonella-derived lipopolysaccharide (LPS). However, a serious disadvantage of these tests, used so far, is the restricted detection of antibodies belonging predominantly to the immunoglobulin class g (IgG). Therefore, a new test was developed to detect three Ig classes (IgM, IgG and IgA). Different constellations between the three Ig classes allow the evaluation of the current infection status of each pig. Under field conditions, this was proved in three different vaccination trials using a commercial Salmonella Typhimurium live vaccine.     

Effect of different mini‐volume colloid centrifugation configurations on flow cytometrically sorted sperm recovery efficiency and quality using a computer‐assisted semen analyzer

Straws of sex‐sorted sperm are usually packaged at a low concentration (e.g., ~2.1 × 10⁶ sperm/ml) and cost significantly more than unsorted conventional semen from the same sire. In order to maximize the efficiency of using sex‐sorted sperm under in vitro fertilization conditions, the selection of an appropriate sperm separation technique is essential. In this study, the effect of using different silane‐coated silica colloid dilutions and layering configurations during centrifugation of sex‐sorted sperm was examined over an extended period of incubation time. Sperm recovery and viability after centrifugation using the colloid separation technique were measured along with several sperm motility parameters using CASA. For this purpose, frozen and thawed sex‐sorted sperm samples were centrifuged using mini‐volume single‐layer (40%, 60% and 80%) and mini‐volume two‐layer (45%/90%, 40%/80% and 30%/60%) separation configurations using PureSperm^®. A single layer of 40% PureSperm^® recovered significantly more sex‐sorted sperm (78.07% ± 2.28%) followed by a single layer of 80% PureSperm^® (68.43% ± 2.33%). The lowest sperm recovery was obtained using a two‐layer PureSperm^® dilution of 45%/90% (47.57% ± 2.33%). Single‐layer centrifugation recovered more sorted sperm (68.67% ± 1.74%) than two layer (53.74% ± 1.74%) (p < .0001). A single layer of 80% PureSperm^® exhibited the highest sorted sperm viability (72.01% ± 2.90%) after centrifugation (p < .05). The mini‐volume single layer of 80% PureSperm^® was determined to be an effective alternative to a two‐layer centrifugation configuration for sex‐sorted sperm selection. In addition, single‐layer colloid dilution of 80% performed either as well as or significantly outperformed the other treatments, as well as the control, with regard to motility (MOT) for all time periods of analysis.     

Ecosystem service supply and vulnerability to global change in Europe

Global change will alter the supply of ecosystem services that are vital for human well-being. To investigate ecosystem service supply during the 21st century, we used a range of ecosystem models and scenarios of climate and land-use change to conduct a Europe-wide assessment. Large changes in climate and land use typically resulted in large changes in ecosystem service supply. Some of these trends may be positive (for example, increases in forest area and productivity) or offer opportunities (for example, "surplus land" for agricultural extensification and bioenergy production). However, many changes increase vulnerability as a result of a decreasing supply of ecosystem services (for example, declining soil fertility, declining water availability, increasing risk of forest fires), especially in the Mediterranean and mountain regions.     

Conditioning Horses at v10 3 Times per Week Does Not Enhance v4

This study examined the effect of exercising horses 3 times per week with two bouts of 5-minutes' duration at their v₁₀. Six Thoroughbreds were treadmill-conditioned for 6 weeks. A standardized exercise test (SET) was performed at the beginning of the conditioning period to determine the blood lactate–running speed (BLRS) relation, and the SET was repeated every 2 weeks. After each SET, the BLRS relation was used to calculate the horse's speed, which produced a blood lactate (LA) concentration of 10 mmol/L (v₁₀) and 4 mmol/L (v₄). Each horse was then conditioned for the next 2 weeks (3 times/week) at its individual v₁₀ for two 5-minute bouts with a 5-minute walking phase in between. Exercise speed was individually adapted to the new v₁₀ every 2 weeks. The v₄ of horses decreased after the first 2 weeks (from 6.23 ± 0.41 m/s to 5.95 ± 0.33 m/s, mean ± SD; P < .05), increased in the following 2 weeks (6.33 ± 0.58 m/s; P < .01), and stayed constant thereafter (P > .05). The conclusion drawn was that exercising horses 3 times per week at their v₁₀ for two 5-minute bouts did not improve v₄.