Untersuchungen zur Europäischen Steinobstvergilbung (ESFY) in Deutschland

From 2003 to 2007 surveys have been conducted in different stone fruit growing regions in southwest Germany to detect European stone fruit yellows (ESFY) disease in Germany. Samplings have been done regularly in selected reference orchards in the regions Neuwieder Becken, Rheinhessen, Vorderpfalz and Südpfalz in summer on trees showing ESFY typical symptoms as well as on branches of trees with unspecific symptoms. All samples have been analysed by PCR for infection with Candidatus Phytoplasma prunorum. The phytoplasma could be detected in all investigated regions on the cultivated Prunus species P. armeniaca, P. persica and P. domestica. No infection was found in wild Prunus species. The main spread of the disease appeared on apricot while peach and European plum were less affected. A good correlation between symptoms and molecular detection of the pathogen could be shown for the typical symptoms in summer and winter for apricot as well as for peach. During regular psyllid captures in the reference orchards the population dynamics of Cacopsylla pruni could be described in southwest Germany for several years. By PCR-testing all collected insects individually a yearly natural infection rate of about 1–2% of all individuals of C. pruni could be calculated.     

Comparison of different in-house test systems to detect parvovirus in faeces of cats

In-house tests for the identification of faecal parvovirus antigen are now available. The majority of these are licensed for canine parvovirus only; but anecdotal information suggests that they will detect feline panleukopenia virus (FPV) as well. This prospective study was designed to compare five commercially available test systems. In total, 200 faecal samples from randomly selected healthy cats (148) and cats with diarrhoea (52) were tested and compared with the results of examination by electron microscopy. Ten cats were positive for FPV and all of these had diarrhoea. In-house canine parvovirus tests can be used to detect FPV. All tests were suitable to screen cats for faecal parvovirus excretion (positive predictive values for the Witness Parvo, the Snap Parvo, the SAS Parvo, the Fastest Parvo Strip, and the Speed Parvo were 100.0, 100.0, 57.1, 38.9, and 100%, respectively, negative predictive values for the Witness Parvo, the Snap Parvo, the SAS Parvo, the Fastest Parvo Strip, and the Speed Parvo were 97.4, 97.9, 98.9, 98.4, and 97.4%, respectively). In-house parvovirus tests may be positive up to 2 weeks after vaccination, and therefore, in recently vaccinated cats positive results do not necessarily mean infection.     

Determining the within-field yield variability from seasonally changing soil conditions

Crop yield variations are strongly influenced by the spatial and temporal availabilities of water and nitrogen in the soil during the crop growth season. To estimate the quantities and distributions of water and nitrogen within a given soil, process-oriented soil models have often been used. These models require detailed information about the soil characteristics and profile architecture (e.g., soil depth, clay content, bulk density, field capacity and wilting point), but high resolution information about these soil properties, both vertically and laterally, is difficult to obtain through conventional approaches. However, on-the-go electrical resistivity tomography (ERT) measurements of the soil and data inversion tools have recently improved the lateral resolutions of the vertically distributed measurable information. Using these techniques, nearly 19,000 virtual soil profiles with defined layer depths were successfully created for a 30 ha silty cropped soil over loamy and sandy substrates in Central Germany, which were used to initialise the CArbon and Nitrogen DYnamics (CANDY) model. The soil clay content was derived from the electrical resistivity (ER) and the collected soil samples using a simple linear regression approach (the mean R² of clay = 0.39). The additional required structural and hydrological properties were derived from pedotransfer functions. The modelling results, derived soil texture distributions and original ER data were compared with the spatial winter wheat yield distribution in a relatively dry year using regression and boundary line analysis. The yield variation was best explained by the simulated soil water content (R² = 0.18) during the grain filling and was additionally validated by the measured soil water content with a root mean square error (RMSE) of 7.5 Vol%.     

The role of N form supply for PGPM‐host plant interactions in maize

The form of nitrogen (N) supply has a significant impact on rhizosphere chemistry and root growth responses of higher plants. The respective effects are also employed as management options to improve nutrient acquisition and to minimize nutrient losses in cropping systems. However, surprisingly little is known concerning the interactions with rhizosphere biota. In this study, we investigated the effects of selected bacterial and fungal inoculants with proven plant growth‐promoting and phosphate (P)‐solubilizing potential (plant growth‐promoting microorganisms, PGPM) in maize with nitrate or stabilized ammonium supply, on soils with limited P availability and sparingly soluble rock phosphate (Rock‐P) applied as P fertilizer. The combination of the bacterial inoculants Pseudomonas sp. DSMZ 13134 (Proradix) and Bacillus amyloliquefaciens FZB42 with ammonium sulphate fertilization, stabilized with the nitrification inhibitor 3,4‐dimethylpyrazole‐phosphate (DMPP), resulted in a superior shoot biomass production (79–111%) and shoot P accumulation (109–235%) as compared with nitrate supply. This effect could be partially attributed to (1) ammonium‐induced rhizosphere acidification via increased root extrusion of protons, (2) promotion of root hair elongation, and (3) increased shoot concentrations of hormonal growth regulators (indole‐3‐acetic acid, zeatin, gibberellic acid). The effects, induced by the microbial inoculants were mainly related to increased root length development (43–44%), associated with a 60% increase in auxin production potential. No inoculant effects were detected on root hair elongation or on chemical modifications of the rhizosphere involved in P solubilisation, such as rhizosphere acidification, release of carboxylates or secretory phosphohydrolases. However, the ammonium‐induced stimulation of root hair elongation increased preferential sites for root colonization by the selected inoculants, which may explain the increase in rhizosphere abundance of PGPMs, exemplarily recorded for the fungal inoculant Trichoderma harzianum OMG16 (210%). The presented data suggest a network of positive interactions between stabilized ammonium fertilization and plant growth‐promoting functions of various bacterial and fungal PGPM inoculants. This offers perspectives to increase the efficiency and the reproducibility of PGPM‐assisted fertilization strategies.     

Silage yield and quality traits in elite maize hybrids and their relationship to elemental concentrations in juvenile plants

European silage maize is cultivated for animal feed and biogas production. We evaluated 210 factorial crosses of elite dent and flint lines in multilocation trials for agronomic and quality traits together with biomass and shoot concentrations of 10 elements in juvenile plants. Significant genotypic variances, mainly due to general combining ability variance of the dent lines, and high heritabilities were observed for dry matter yield (DMY) and quality traits. DMY was not correlated with quality traits, but methane fermentation yield (MFY) and metabolizable energy content (MEC) showed significant correlations with starch and fibre content. Concentrations of elements N,P,S,K were positively correlated with each other but only in few cases correlated with DMY and quality traits. Parent lines with contrasting P concentrations differed in root morphology traits. Results support DMY as primary trait for selection of silage maize hybrids, but MFY is of negligible importance in breeding for biogas contrary to MEC for animal feed. Neither biomass nor elemental composition of juvenile plants were of predictive value for final DMY or quality traits.     

EDCs‐induced glucocorticoid receptor related genes expression of the river pufferfish,Takifugu obscurus

Endocrine disrupting chemicals (EDCs) are of substantial concern when contaminating waters. We studied gene expression of larvae from river pufferfish, Takifugu obscurus exposed to EDCs. We cloned the full‐ or partial‐length cDNA sequence of genes related to the cortisol pathway, such as the glucocorticoid receptor (GR), mineralocorticoid receptor (MR), heat shock protein (HSP) 70 and 90, phosphoenolpyruvate carboxykinase (PEPCK) and the FK506‐binding protein 4 (FKBP52). The tissue and time‐dependent expression of mRNA was studied by real‐time PCR in T. obscurus exposed to two representative EDCs (bisphenol‐A and 4‐tert‐octylphenol). HSP70, HSP90, MR and FKBP52 mRNA expression level was much higher than GR and PEPCK expression. GR mRNA expression level was significantly upregulated after 48 h in both EDC‐treated fish groups compared with the control. Both groups also showed down‐regulation patterns after 48 h. The initial expression of PEPCK in both groups was down‐regulated after 24 h. In the bisphenol‐A treated group, the expression of FKBP52 showed substantially high up‐regulation from 6 to 48 h after exposure, and then strikingly reduced its expression level at 72 h. Our results provide insights into the EDCs metabolizing system of T. obscurus and offers baseline information for further research related to the possible use as a bio‐indicator of this commercially important aquaculture fish species.     

Relevance of feline calicivirus, feline immunodeficiency virus, feline leukemia virus, feline herpesvirus and Bartonella henselae in cats with chronic gingivostomatitis

Despite its common occurrence, the aetiology of chronic gingivostomatitis in cats remains uncertain. Aetiology is likely multifactorial, and several infectious agents may be associated with chronic gingivostomatitis. The purpose of this study was to investigate the prevalence of feline calicivirus (FCV), feline immunodeficiency virus (FIV), feline leukemia virus (FeLV), feline herpesvirus (FHV), and Bartonella henselae (B. henselae) in cats with chronic gingivostomatitis and in an age-matched control group. In addition, other factors, e. g., environmental conditions were investigated. In 52 cats with chronic gingivostomatitis and 50 healthy age-matched control cats, the presence of FCV ribonucleic acid (RNA), and FHV deoxyribonucleic acid (DNA) (polymerase chain reaction [PCR] from oropharyngeal swabs), and B. henselae DNA (PCR from oropharyngeal swabs and blood), as well as FeLV antigen (serum), and antibodies against FCV, B. henselae, and FIV (serum) were examined. FCV RNA was significantly more common in cats with chronic gingivostomatitis (53.8%, p < 0.001) than in controls (14.0%); a significant difference was also found in the prevalence of antibodies to FCV between the cats with chronic gingivostomatitis (78.8%, p = 0.023) and controls (58.0%). Of the other infectious agents investigated, there was no significant difference in the prevalence between the cats with chronic gingivostomatitis and the controls. The results of this study allow the conclusion that FCV, but no other infectious agents, is commonly associated with chronic gingivostomatitis in cats.     

TLR13 recognizes bacterial 23S rRNA devoid of erythromycin resistance-forming modification

Host protection from infection relies on the recognition of pathogens by innate pattern-recognition receptors such as Toll-like receptors (TLRs). Here, we show that the orphan receptor TLR13 in mice recognizes a conserved 23S ribosomal RNA (rRNA) sequence that is the binding site of macrolide, lincosamide, and streptogramin group (MLS) antibiotics (including erythromycin) in bacteria. Notably, 23S rRNA from clinical isolates of erythromycin-resistant Staphylococcus aureus and synthetic oligoribonucleotides carrying methylated adenosine or a guanosine mimicking a MLS resistance-causing modification failed to stimulate TLR13. Thus, our results reveal both a natural TLR13 ligand and specific mechanisms of antibiotic resistance as potent bacterial immune evasion strategy, avoiding recognition via TLR13.