Infection pressure of human alveolar echinococcosis due to village and small town foxes (<Emphasis Type="Italic">Vuples vulpes</Emphasis>) living in close proximity to residents

This study investigated the epidemiological and ecological factors to assess the infection pressure of alveolar echinococcosis to human which are living in villages and small towns. Foxes and fox faeces were examined for Echinococcus multilocularis and foxes were observed by radio telemetry in Upper Bavaria, Germany. Forty-three percent of the village foxes (n = 65) had been infected with E. multilocularis. This prevalence rate did not differ significantly from the prevalence among rural foxes, which was 39% (n = 33; χ ² = 0.12, df = 1, p = 0.727) determined by the intestinal scraping technique. PCR analyses of fox faeces showed a higher infection rate of 35% (n = 26) among rural foxes than among foxes in villages and small towns (26%, n = 69; χ ² = 0.68, df = 1, p = 0.411). One quarter of the fox faecal samples come from private gardens of residents. The radio-tracking study on 17 foxes showed that foxes preferred the built-up area and grassland outside the villages. Village foxes concentrated their activity within a range of 500 m around the settlement. Sixty-four percent of all bearings for radio-tracked foxes showed positions in areas outside the town, and 36% of bearings were within the settlement. Village foxes, which are infected with E. multilocularis, are able to carry the parasite continuously into settlements and fox faeces present an immediate source of infection to humans, especially within their gardens. Therefore, foxes are responsible for environmental E. multilocularis egg contamination in the vicinity of humans, leading to an infection risk to inhabitants of villages and small towns.     

Effects of reproductive status and management on cortisol secretion and fertility of oestrous horse mares

Stressful events may contribute to low reproductive efficiency due to glucocorticoid-mediated inhibition of hormone secretion in a variety of species. We therefore investigated effects of stress related to management of mares around artificial insemination on secretion of cortisol and fertility parameters. To avoid further disturbance of mares by frequent blood sampling, faecal cortisol metabolites (fCM) were determined instead (sample collection at 8-h intervals). A total of 50 mares (16 maiden, 17 barren, 12 foaling, 5 teaching mares) were included in the study. Mares were brought to the AI centre in vans or trailers (driving time between 30 min and 5 h). Teaching mares were housed in the clinic and had therefore not to be transported. Mares were inseminated either with fresh/cooled-shipped or frozen semen. Rectal palpations and ultrasound examinations were performed at 24- to 48-h intervals, in animals inseminated with frozen semen at 6-h intervals during the last 48 h before ovulation. In maiden, barren and foaling mares, fCM concentrations in faeces tended to be higher than in teaching mares at all times after arrival at the AI centre. At 24 and 48 h after arrival, fCM concentrations in maiden mares were significantly higher than in teaching mares (24h: maiden mares 12.3+/-3.1 ng/g, barren mares 8.5+/-1.2 ng/g, foaling mares 11.0+/-2.4 ng/g, teaching mares 3.8+/-0.6 ng/g, p<0.05). The time from arrival at the AI centre to detection of ovulation did not differ among the different groups of mares and was 4.5+/-0.4, 5.0+/-0.5, 3.8+/-0.5 and 5.6+/-0.9 days in maiden, barren, foaling and teaching mares, respectively (n.s.). Pregnancy rates were 53, 53, 55 and 60%, respectively (n.s.). The time from arrival at the AI centre to detection of ovulation was 4.4+/-0.3 days and 4.9+/-0.3 days in mares inseminated with fresh/shipped (n=39) or frozen semen (n=11; n.s.), respectively. The frequency of follicular checks influenced fCM secretion and was statistically significant at 16 h before ovulation (fresh/shipped semen: fCM 6.9+/-0.7 ng/g faeces, frozen semen: fCM 16.9+/-5.2 ng/g faeces, p<0.01). In the mare, gynaecological examinations seem to act as stressors and may increase cortisol secretion. However, this does not negatively influence fertility and in animals familiar with that procedure fCM concentrations are not elevated.     

Label-free detection of single nucleotide polymorphisms utilizing the differential transfer function of field-effect transistors

We present a label-free method for the detection of DNA hybridization, which is monitored by non-metallized silicon field-effect transistors (FET) in a microarray approach. The described method enables a fast and fully electronic readout of ex situ binding assays. The label-free detection utilizing the field-effect is based on the intrinsic charge of the DNA molecules and/or on changes of the solid–liquid interface impedance, when biomolecules bind to the sensor surface. With our sensor system, usually a time-resolved, dc readout is used. In general, this FET signal suffers from sensor drift, temperature drift, changes in electrolyte composition or pH value, influence of the reference electrode, etc. In this article, we present a differential ac readout concept for FET microarrays, which enables a stable operation of the sensor against many of these side-parameters, reliable readout and a possibility for a quick screening of large sensor arrays. We present the detection of point mutations in short DNA samples with this method in an ex situ binding assay.     

Seasonal Viral Loop Dynamics in Two Large Ultraoligotrophic Antarctic Freshwater Lakes

The effect of viruses on the microbial loop, with particular emphasis on bacteria, was investigated over an annual cycle in 2003–2004 in Lake Druzhby and Crooked Lake, two large ultraoligotrophic freshwater lakes in the Vestfold Hills, Eastern Antarctica. Viral abundance ranged from 0.16 to 1.56 × 10⁹ particles L^-1;1 and bacterial abundances ranged from 0.10 to 0.24 × 10⁹ cells L^-1;1, with the lowest bacterial abundances noted in the winter months. Virus-to-bacteria ratios (VBR) were consistently low in both lakes throughout the season, ranging from 1.2 to 8.4. lysogenic bacteria, determined by induction with mitomycin C, were detected on three sampling occasions out of 10 in both lakes. In Lake Druzhby and Crooked Lake, lysogenic bacteria made up between 18% and 73% of the total bacteria population during the lysogenic events. Bacterial production ranged from 8.2 to 304.9 × 10⁶ cells L^-1;1 day^-1;1 and lytic viral production ranged from 47.5 to 718.4 × 10⁶ viruslike particles L^-1;1 day^-1;1. When only considering primary production, heterotrophic nanoflagellate (HNF) grazing and viral lysis as the major contributors to the DOC pool (i.e., autochthonous sources), we estimated a high contribution from viruses during the winter months when >60% of the carbon supplied to the DOC pool originated from viral lysis. In contrast, during the summer <20% originated from viral lysis. Our study shows that viral process in ultraoligotrophic Antarctic lakes may be of quantitative significance with respect to carbon flow especially during the dark winter period.     

Is microbial community composition in boreal forest soils determined by pH,C-to-N ratio,the trees,or all three?

In Fennoscandian boreal forests, soil pH and N supply generally increase downhill as a result of water transport of base cations and N, respectively. Simultaneously, forest productivity increases, the understory changes from ericaceous dwarf shrubs to tall herbs; in the soil, fungi decrease whereas bacteria increase. The composition of the soil microbial community is mainly thought to be controlled by the pH and C-to-N ratio of the substrate. However, the latter also determines the N supply to plants, the plant community composition, and should also affect plant allocation of C below ground to roots and a major functional group of microbes, mycorrhizal fungi. We used phospholipid fatty acids (PLFAs) to analyze the potential importance of mycorrhizal fungi by comparing the microbial community composition in a tree-girdling experiment, where tree belowground C allocation was terminated, and in a long-term (34 years) N loading experiment, with the shifts across a natural pH and N supply gradient. Both tree girdling and N loading caused a decline of ca. 45% of the fungal biomarker PLFA 18:2ω6,9, suggesting a common mechanism, i.e., that N loading caused a decrease in the C supply to ectomycorrhizal fungi just as tree girdling did. The total abundance of bacterial PLFAs did not respond to tree girdling or to N loading, in which cases the pH (of the mor layer) did not change appreciably, but bacterial PLFAs increased considerably when pH increased across the natural gradient. Fungal biomass was high only in acid soil (pH < 4.1) with a high C-to-N ratio (>38). According to a principal component analysis, the soil C-to-N ratio was as good as predictor of microbial community structure as pH. Our study thus indicated the soil C-to-N ratio, and the response of trees to this ratio, as important factors that together with soil pH influence soil microbial community composition.     

Fractional <Superscript>13</Superscript>C enrichment of isolated carbons using [1-<Superscript>13</Superscript>C]- or [2-<Superscript>13</Superscript>C]-glucose facilitates the accurate measurement of dynamics at backbone C<Superscript>α</Superscript> and side-chain methyl positions in proteins

A simple labeling approach is presented based on protein expression in [1-¹³C]- or [2-¹³C]-glucose containing media that produces molecules enriched at methyl carbon positions or backbone C^α sites, respectively. All of the methyl groups, with the exception of Thr and Ile(δ1) are produced with isolated ¹³C spins (i.e., no ¹³C–¹³C one bond couplings), facilitating studies of dynamics through the use of spin-spin relaxation experiments without artifacts introduced by evolution due to large homonuclear scalar couplings. Carbon-α sites are labeled without concomitant labeling at C^β positions for 17 of the common 20 amino acids and there are no cases for which ¹³C^α−¹³CO spin pairs are observed. A large number of probes are thus available for the study of protein dynamics with the results obtained complimenting those from more traditional backbone ¹⁵N studies. The utility of the labeling is established by recording ¹³C R _1ρ and CPMG-based experiments on a number of different protein systems.     

Consistent detection of QTLs for crown rust resistance in Italian ryegrass (<Emphasis Type="Italic">Lolium multiflorum</Emphasis> Lam.) across environments and phenotyping methods

Crown rust, caused by Puccinia coronata f. sp. lolii, is one of the most important diseases of temperate forage grasses, such as ryegrasses (Lolium spp.), affecting yield and nutritional quality. Therefore, resistance to crown rust is a major goal in ryegrass breeding programmes. In a two-way pseudo-testcross population consisting of 306 Lolium multiflorum individuals, multisite field evaluations as well as alternative methods based on artificial inoculation with natural inoculate in controlled environments were used to identify QTLs controlling resistance to crown rust. Disease scores obtained from glasshouse and leaf segment test (LST) evaluations were highly correlated with scores from a multisite field assessment (r = 0.66 and 0.79, P < 0.01, respectively) and thus confirmed suitability of these methods for crown rust investigations. Moreover, QTL mapping based on a linkage map consisting of 368 amplified fragment length polymorphism (AFLP) and simple sequence repeat (SSR) markers revealed similar results across different phenotyping methods. Two major QTLs were consistently detected on linkage group (LG) 1 and LG 2, explaining up to 56% of total phenotypic variance (V _p). Nevertheless, differences between position and magnitude of QTLs were observed among individual field locations and suggested the existence of specific local pathogen populations. The present study not only compared QTL results among crown rust evaluation methods and environments, but also identified molecular markers closely linked to previously undescribed QTLs for crown rust resistance in Italian ryegrass with the potential to be applied in marker-assisted forage crop breeding. Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users.     

Cyclin-dependent kinase 5 is an upstream regulator of mitochondrial fission during neuronal apoptosis

Under physiological conditions, mitochondrial morphology dynamically shifts between a punctuate appearance and tubular networks. However, little is known about upstream signal transduction pathways that regulate mitochondrial morphology. We show that mitochondrial fission is a very early and kinetically invariant event during neuronal cell death, which causally contributes to cytochrome c release and neuronal apoptosis. Using a small molecule CDK5 inhibitor, as well as a dominant-negative CDK5 mutant and RNAi knockdown experiments, we identified CDK5 as an upstream signalling kinase that regulates mitochondrial fission during apoptosis of neurons. Vice versa, our study shows that mitochondrial fission is a modulator contributing to CDK5-mediated neurotoxicity. Thereby, we provide a link that allows integration of CDK5 into established neuronal apoptosis pathways.     

Apoptotic DNA fragmentation is not related to the phosphorylation state of histone H1

Changes in chromatin structure, histone phosphorylation and cleavage of DNA into nucleosome-size fragments are characteristic features of apoptosis. Since H1 histones bind to the site of DNA cleavage between nucleosomal cores, the question arises as to whether the state of H1 phosphorylation influences the rate of internucleosomal cleavage. Here, we tested the relation between DNA fragmentation and H1 phosphorylation both in cultured cells and in vitro. In Jurkat cells, hyperosmotic mannitol concentration resulted in apoptosis, including nucleosomal fragmentation, whereas apoptosis induction by increased NaCl concentration was not accompanied by DNA fragmentation. However, both treatments induced dephosphorylation of H1 histones. In contrast, treatment of Raji cells with alkylphosphocholine led to induction of apoptosis with internucleosomal fragmentation, albeit without notable histone H1 dephosphorylation. These results demonstrate that dephosphorylation of H1 histones is neither a prerequisite for nor a consequence of internucleosomal cleavage. Moreover, we observed with an in vitro assay that the known enhancing effect of H1 histones on the activity of the apoptosis-induced endonuclease DFF40 is independent of the subtype or the phosphorylation state of the linker histone.