The (Me5C5)Si+ cation: a stable derivative of HSi+

The reaction of decamethylsilicocene, (Me5C5)2Si, with the proton-transfer reagent Me5C5H2+B(C6F5)4- produces the salt (Me5C5)Si+ B(C6F5)4(2), which can be isolated as a colorless solid that is stable in the absence of air and moisture. The crystal structure reveals the presence of a cationic pi complex with an eta5-pentamethylcyclopentadienyl ligand bound to a bare silicon center. The 29Si nuclear magnetic resonance at very high field (delta = - 400.2 parts per million) is typical of a pi complex of divalent silicon. The (eta5-Me5C5)Si+ cation in 2 can be regarded as the "resting state" of a silyliumylidene-type (eta1-Me5C5)Si+ cation. The availability of 2 opens new synthetic avenues in organosilicon chemistry. For example, 2 reacted with lithium bis(trimethylsilyl)amide to give the disilene E-[(eta1-Me5C5)[N(SiMe3)2]Si]2(3).     

Insights into the dynamics of endemic Coxiella burnetii infection in cattle by application of phase-specific ELISAs in an infected dairy herd

Serological diagnosis of acute and chronic Q fever in humans relies on detection of antibodies to phase I (PhI) and II (PhII) antigens of Coxiella (C.) burnetii. Although phase-specific antigens are available, they are not yet used in ruminants as they are in humans. This study focuses on phase-specific serology as a tool for analysis of the dynamics of infection in cattle. As a prerequisite, sero-prevalence in Bavarian cattle (1) and sero-prevalences for age-groups (2) were determined by ELISA (CHEKIT Q-Fever; mix of PhI/PhII-antigen). Subsequently, phase-specific antigens were coated onto ELISA plates individually and tests were simultaneously applied in an endemically infected herd with about 90 dairy cows and 250 calves/heifers in April 2005, March 2006 and retrospectively in May and October 2004. From April 2005 onward, placentas were analysed for C. burnetii by PCR (3). (1) Sero- and herd prevalences based on 21,051 sera from 603 Bavarian dairy farms collected in 2003 were 14.8% ± 0.48% and 72.3% ± 3.6%, respectively. (2) Analysis of 3965 animals from 105 farms for which age was reported revealed a base level of sero-prevalence of less than 5% in 1-2 years old animals, it increased to 15% in 2-3 years old and reached a plateau (25-30%) in cows four years and older. (3) In May 2004 and April 2005 a peak of PhI(-)/PhII(+)-prevalence in primiparous cows (2.0-3.5 years) was observed; but not in October 2004 and March 2006. The PhI(-)/PhII(+)-pattern in primiparous cows changed to negative (one-third), PhI(+)/PhII(+) (1/3) or persisted (1/3). In contrast, sero-conversion was rare in multiparous cows (>3.5 years). If the PhI(-)/PhII(+) pattern was detected, it was due to an infection in preceding years. This pattern persisted (2/3) or changed to negative (1/3); a change to PhI(+)/PhII(+) did not occur. PhI(-)/PhII(+) in heifers (1-2 years) always changed to negative. Detection of PhII-antibodies was significantly associated with PCR-positive placentas. Remarkably, 45% of sera with the PhI(-)/PhII(+) pattern were negative for the CHEKIT Q-Fever ELISA, thus this test missed an important group of infected animals.     

Eignen sich die Mauerbienen Osmia bicornis und Osmia cornuta als Best?uber im Obstbau?

Mason bees have been successfully managed as orchard pollinators in Japan and USA for many decades. Recently, the European species Osmia bicornis (L.) and Osmia cornuta (Latr.) attract more interest as pollinators in fruit orchards in Germany. Several studies indicate the potential of these mason bees as pollinators of pome and stone fruit. Here, we investigated the composition of the pollen loads in the brood cells of these two mason bees in fruit orchards different in habitat characteristics. At eight study sites, trap nests and cocoons of O. bicornis and O. cornuta were installed. During fruit tree blossom, pollen was sampled every two weeks and the percentage of Rosaceae pollen was identified. Landscape characteristics were assessed in a radius of 250 m from the trap nests. At all eight study sites, O. bicornis and O. cornuta collected pollen of Rosaceae. The percentage of Rosaceae pollen in the samples and the local habitat quality of the foraging sites were negatively correlated. In fruit orchards with a low diversity of suitable foraging habitats, brood cells contained a relatively high percentage of fruit tree pollen. These results indicate the potential of O. bicornis and O. cornuta as efficient pollinators in intensively managed fruit orchards. However, intensive fruit orchards appear less suitable as habitats for these mason bees to establish an endogenous pollinator population. Hence, the introduction and management of mason bees in orchards will improve pollination.     

A Four-Year Study on Influence of Biosolids/MSW Cocompost Application in Less Productive Soils In Alberta: Nutrient Dynamics

Composting municipal solid waste and biosolids and applying it on arable land have become an alternative way to treat waste in large municipalities in North America. However, cost of compost transportation and application constrains the compost use on the land further away from where it is produced. A four-year experiment was conducted (1998-2001) in less productive soils in Alberta to determine the effect of once in four year application of cocompost on soil nutrient dynamics and crop N uptakes. There were three crop blocks: barley (Hordeum vulgare L.), wheat (Triticum aestivum L), and canola (Brassica rapa), and they were rotated annually. The compost was only applied in 1998 at a rate of 50, 100 and 200 t/ha. Soil samples were taken in spring of every year after initial compost application to determine extractable N, P, K, S, Cu, Zn, Soil pH and EC. Each year, crops were harvested and N uptake was determined. Total concentrations of an array of heavy metals in the first year and fourth year after compost application were determined as well. The results showed that the release of N from the compost was high in the first year after compost application and then declined in each subsequent year. Similar to that release pattern was sulphur. The release of phosphorus from compost was steady throughout the four-year experimental time. Crop N uptake from compost application varied with crops and sites. The over all N use efficiency for three crops and two sites was 11%, 3%, 1% and 2% for the first and subsequent three years. The total heavy metal concentrations in the compost amended soils in the first and fourth year after compost application were similar, and they were below the standard of Canadian Fertilizer Act. Our results showed that N released from compost occurred mostly in the first two years after application, suggesting that an application frequency of once in every second year may be better than the once in every four year application strategy, especially with 100 t/ha application rate.     

Splitting nitrogen applications improves wheat storage protein composition under low N supply

For the baking quality of wheat flours, the composition and concentration of grain protein are crucial. It is common practice to use late nitrogen (N) application to increase grain protein concentration (GPC) and hence, improve baking quality. However, the use of N fertilizer—particularly shortly before harvest—involves environmental risks. With the suitability of GPC as a parameter for baking quality predictions being more and more questioned, there are further investigations needed considering not only the GPC but also the composition of grain protein. Gluten protein composition varies depending on genotype and environmental factors, such as weather conditions and fertilization rate. To examine whether the effect of a split N application varies under different amounts of total N supply, this study investigates the effects of split nitrogen application on grain protein concentration and composition of wheat (Triticum aestivum L. cv. JB Asano) at four different N fertilization levels (0.8; 1.0; 1.2, and 1.4 g N pot^?1) in a pot experiment. The GPC was affected by both, N fertilization level and split N application. In this experiment, the minimum GPC of 13%, which is required for class A wheat varieties, was only achieved when N supply was moderate (at least 1.2 g N per pot). Considering the storage protein composition, the split N application influenced the proportion of α‐/β‐gliadins and γ‐gliadins, the alterations being inconsistent. The ratio of high molecular weight (HMW) to low molecular weight (LMW) glutenin subunits was increased by the split N application only at the lowest N fertilization level. It is concluded that splitting N fertilization into three doses and hence applying one dose of N late in the season can still be a useful approach to improve GPC as well as protein composition – especially when the total N supply is low.     

Fat status in Lohmann Silver and Lohmann tradition laying hens kept in modified small group housing systems, small group housing systems, furnished cages and an aviary system

The influence of different housing systems on adiposis of liver, abdomen and heart was evaluated in 670 Lohmann Silver (LS) and 240 Lohmann Tradition (LT) laying hens during two trials. Examinations took place in the 3rd, 6th, 9th and 12th laying month. In addition, serum concentration of triglycerides (TRI) was analysed. Housing systems included in this study were a furnished cage system (Aviplus (AP)), a small group housing system (Eurovent 625a-EU (EV)), with perches on the same (first trial) and on different levels (second trial, MEV), and an aviary system (Voliere Natura (AV)). In both trials, a significantly lower fat status of abdomen and liver could be observed in hens housed in AV. Consistently in both trials, body weight and housing system had the largest influence on fat status of liver, abdomen and heart. Scores of fat status of liver and abdomen in EV and MEV were in between of those observed in AV and AP, while heart fat status did not differ among housing systems. With an increasing macroscopic fat status of the liver, liver weight and TRI concentration significantly increased. Different perch positions in MEV did not have a significant influence on fat status in layers.     

Influence of vitamin E on organic matter fermentation,ruminal protein and fatty acid metabolism,protozoa concentrations and transfer of fatty acids

Vitamin E (Vit. E) is discussed to influence ruminal biohydrogenation. The objective of this study was to investigate the influence of a Vit. E supplementation on rumen fermentation characteristics, ruminal microbial protein synthesis as well as ruminal organic matter fermentation. Furthermore, we aimed to investigate the influence of Vit. E supplementation on short‐chain fatty acids (SCFA) and protozoa concentrations in the rumen and, in addition, on transfer rates of middle‐chain and long‐chain fatty acids into the duodenum in lactating dairy cows. Eight rumen and duodenum fistulated German Holstein cows were assigned to either a group receiving 2,327 IU/d Vit. E (138.6 IU/kg DM DL‐α‐tocopherylacetate; n = 4) or a control group (23.1 IU/kg DM; n = 4). Neither ruminal protein synthesis nor organic matter fermentation was influenced by treatment. Vit. E did not act on the concentrations of short‐chain fatty acids and protozoa in rumen fluid. Duodenal flow of C13:0 (1.3 versus 0.2 g/d, p = 0.014) and iso‐C14:0 (1.0 versus 0.5 g/d, p = 0.050) was higher in the Vit. E group. We observed a trend for higher duodenal flows for C12:0 (1.6 versus 0.9 g/d, p = 0.095) and anteiso‐C15:0 (12.2 versus 8.9 g/d, p = 0.084). Transfer rate of C12:0 tended to be higher in the Vit. E group (125.61 versus 73.96, p = 0.082). No other transfer rates were affected by treatment. Further studies are necessary to investigate the influence of Vit. E on rumen microbiota and their fatty acid production as well as on the impact of different doses of Vit. E supplementation on variables of protein synthesis efficiency.