Conformational switches modulate protein interactions in peptide antibiotic synthetases

Protein dynamics plays an important role in protein function. Many functionally important motions occur on the microsecond and low millisecond time scale and can be characterized by nuclear magnetic resonance relaxation experiments. We describe the different states of a peptidyl carrier protein (PCP) that play a crucial role in its function as a peptide shuttle in the nonribosomal peptide synthetases of the tyrocidine A system. Both apo-PCP (without the bound 4'-phosphopantetheine cofactor) and holo-PCP exist in two different stable conformations. We show that one of the apo conformations and one of the holo conformations are identical, whereas the two remaining conformations are only detectable by nuclear magnetic resonance spectroscopy in either the apo or holo form. We further demonstrate that this conformational diversity is an essential prerequisite for the directed movement of the 4'-PP cofactor and its interaction with externally acting proteins such as thioesterases and 4'-PP transferase.     

Carbon stocks of soil and vegetation on Danubian floodplains

Riparian forests are assumed to play a crucial role in the global carbon cycle. However, little data are available on C stocks of floodplains in comparison to other terrestrial ecosystems. In this study, we quantified the C stocks of aboveground biomass and soils of riparian vegetation types at 76 sampling sites in the Donau‐Auen National Park in Austria. Based on our results and a remotely sensed vegetation map, we estimated total C stocks. Carbon stocks in soils (up to 354 t ha^–1 within 1 m below surface) were huge compared to other terrestrial ecosystems. As expected, soils of different vegetation types showed different texture with a higher percentage of sandy soils at the softwood sites, while loamy soils prevailed at hardwood sites. Total C stocks of vegetation types were significantly different, but reflect differences in woody plant biomass rather than in soil C stocks. Mature hardwood and cottonwood forests proved to have significantly higher total C stocks (474 and 403 t ha^–1, respectively) than young reforestations (217 t ha^–1) and meadows (212 t ha^–1). The C pools of softwood forests (356 t ha^–1) ranged between those of hardwood/cottonwood forests and of reforestations/meadows. Our study proves the relevance of floodplains as possible C sinks, which should be increasingly taken into account for river management. Furthermore, we conclude that plant‐species distribution does not indicate the conditions of sedimentation and soil C sequestration over the time span of interest for the development of soil C stocks.     

Paratuberculosis in a miniature donkey (Equus asinus f. asinus)

Paratuberculosis is mainly an infectious disease of ruminants with worldwide distribution. Infection occurs in early stages of life. Other animal species beyond ruminants are rarely affected, however, experimental and natural infections are possible. A case of paratuberculosis in a miniature donkey (Equus asinus f. asinus) with typical clinical and pathomorphological changes is reported here. Lesions were mainly observed in the intestine. Causative for the profuse diarrhoea with emaciation was massive diffuse granulomatous enteritis involving large quantities of acid-fast organism mainly in macrophages. Granulomatous inflammation with acid-fast bacilli again in macrophages to a lesser degree could be detected in the liver. Mycobacterium avium subsp. paratuberculosis (MAP) was isolated from intestinal contents after an incubation period of four weeks. MAP-specific DNA (IS900 and f57) was detected by polymerase chain reaction in culture material. Additionally MAP-isolates were characterized by multi-target genotyping (MIRU-VNTR- and MLSSR-typing). Isolates belonged to the Type II group and exhibited a unique genotype different from other MAP strains in Germany. The donkey originated from a donkey breeding farm in France with intensive free ranging cattle in the neighbourhood and could have been infected there. Donkeys should be considered as paratuberculosis-susceptible animals in exceptional cases and as possible reservoirs or disseminators of infection.     

Production of viral vaccines for veterinary use

This review provides inside information on the production of vaccines for veterinary use. The vaccines against rinderpest as well as foot and mouth disease are considered milestones in the history of veterinary vaccine production. Modern vaccines are based on the scientific progress in virology, cell biology and immunology. While naturally occurring attenuated viruses or viruses obtained after passage in different animal species or cell culture were used as vaccine strains in the early vaccines, nowadays targeted mutagenesis can be applied to generate vaccine virus strains. In principle, the antigen production process is the same for live and inactivated vaccines. The vaccine virus is usually grown in cell culture, either in roller bottles or bioreactors. Most live vaccines are freeze-dried in order to enable storage in the refridgerator for a longer period. To this end, a so-called stabilizer is added to the culture medium. The inactivation of the vaccine virus for the production of killed vaccines is done by physical or chemical treatments that lead to denaturation of the proteins or damage of the nucleic acids. The inactivated antigen may be further purified and mixed with an adjuvant. The quality standards for vaccines are layed down in international regulations and laws. Numerous tests are performed during the different production steps and on the final product in order to warrant the quality of each batch.     

Determination of alpha-amanitin in serum and liver by multistage linear ion trap mass spectrometry

This paper describes a rapid LC-MS/MS/MS method for the analysis of alpha-amanitin in serum and liver. Serum was initially prepared by precipitation of proteins with acetonitrile and subsequent removal of acetonitrile with methylene chloride. Liver was prepared by homogenization with aqueous acetonitrile and subsequent removal of acetonitrile using methylene chloride. For both matrices, the aqueous phase was then extracted using mixed-mode C18/cation exchange SPE cartridges and analyzed on a linear ion trap LC-MS system. Standards were prepared in extracts of control matrix. Seven replicate fortifications of serum at 0.001 mug/g (1 ng/g) of alpha-amanitin gave a mean recovery of 95% with 8.8% CV (relative standard deviation) and a calculated method detection limit of 0.26 ng/g. Seven replicates of control liver fortified at 1 ng/g gave a mean recovery of 98% with 17% CV and a calculated method detection limit of 0.50 ng/g. This is the first report of a positive mass spectrometric identification and quantitation of alpha-amanitin in serum and liver from suspect human and animal intoxications.     

Biological Seed Treatment of Cereals with Fresh and Long-term Stored Formulations of Clonostachys rosea: Biocontrol Efficacy Against Fusarium culmorum

In six field experiments, seed treatment with Clonostachys rosea (IK726) significantly reduced disease caused by Fusarium culmorum. IK726 was active against the pathogen at average soil temperatures at sowing ranging from 6.2 to 12 °C. Both in the field experiments and in growth chamber experiments conducted in sand, dried and stored conidia of IK726 controlled F. culmorum as effectively as freshly harvested conidia. A high correlation was found between disease index ratings from field experiments and from corresponding growth chamber sand tests. Amendment with the stickers Pelgel or Sepiret did not influence control activity. The effective dosages of IK726 (cfu/seed) were estimated in bioassays and were very similar for freshly harvested conidia and for dried conidia. With a density of > 5×10³ conidia per seed more than 80% disease control was repeatedly obtained with both types of conidia.     

Assessment of acute injuries, exposure to environmental toxins, and five-year health surveillance of New York Police Department working dogs following the September 11, 2001, World Trade Center terrorist attack

OBJECTIVE: To determine deployment logistics of New York Police Department (NYPD) working dogs that assisted in relief efforts at the World Trade Center (WTC) site following the September 11, 2001, terrorist attack; establish types and rates of related acute injuries and illnesses; identify environmental toxin exposures; and determine long-term (ie, 5-year) health effects of deployment. DESIGN: Prospective cohort study. ANIMALS: 27 working dogs. PROCEDURES: Deployment logistics for the period from September 11, 2001, through May 30, 2002, were determined, and acute health disorders were identified by means of physical examination; a questionnaire; interviews with dog handlers; and toxicologic (blood and hair samples), clinicopathologic, microbiologic (nasal swab specimens submitted for Bacillus anthracis culture), and radiographic methods. Long-term health surveillance ended September 21, 2006. RESULTS: Dogs worked a total of 1,428 days (15,148 hours) at the site. Seventeen of the 27 (62.9%) dogs had health disorders during the first week. Specific conditions included fatigue (incidence rate [events/1,000 active deployment hours], 13.1), conjunctival irritation (13.1), respiratory tract problems (12.4), decreased appetite (10.8), dehydration (10), and cuts (9.3). Only minor hematologic and serum biochemical abnormalities were identified. Bacterial culture of nasal swab specimens did not yield B anthracis. Only mild and infrequent health conditions were identified during the 5-year follow-up period. None of the dogs were identified as having chronic respiratory tract disease. Six dogs died of various causes. CONCLUSIONS AND CLINICAL RELEVANCE: Results suggested that acute injuries and illnesses were common among NYPD working dogs deployed to the WTC disaster site, but that longterm health complications were minimal.     

Delineation of management zones with spatial data fusion and belief theory

Precision Agriculture - Precision agriculture, as part of modern agriculture, thrives on an enormously growing amount of information and data for processing and application. The spatial data used...     

Plant rhizodeposition — an important source for carbon turnover in soils

The soil organic matter plays a key role in ecological soil functions, and has to be considered as an important CO₂ sink on a global scale. Apart from crop residues (shoots and roots), left over on the field after harvest, carbon and nitrogen compounds are also released by plant roots into the soil during vegetation, and undergo several transformation processes. Up to now the knowledge about amount, composition, and turnover of these root‐borne compounds is still very limited. So far it could be demonstrated with different plant species, that up to 20 % of photosynthetically fixed C are released into the soil during vegetation period. These C amounts are ecological relevant. Depending on assimilate sink strength during ontogenesis, the C release varies with plant age. A large percentage of these root‐borne substances were rapidly respired by microorganisms (64—86 %). About 2—5 % of net C assimilation was kept in soil. The root exudates of maize were mainly water‐soluble (79 %), and in this fraction about 64 % carbohydrates, 22 % amino acids/amides and 14 % organic acids could be identified. Plant species and in some cases also plant cultivars varied strongly in their root exudation pattern. Under non‐sterile conditions the exuded compounds were rapidly stabilized in water‐insoluble forms and bound preferably to the soil clay fraction. The binding of root exudates to soil particles also improved soil structure by increasing aggregate stability. Future research should focus on quantification and characterization of root‐borne C compounds during the whole plant ontogenesis. Apart from pot experiments with ¹⁴CO₂ labeling, it is necessary to conduct model field experiments with ¹³CO₂ labeling in order to be able to distinguish between CO₂ originating from the soil C pool and rhizosphere respiration, originating from plant assimilates. Such a separation is necessary to assess if soils are sources or sinks of CO₂. The incorporation of root‐borne C (¹⁴C, ¹³C) into soil organic matter of different stability is also of particular interest.