Incidence and significance of treponemes in animals

The genus Treponema consists of various species. Currently most of them are not cultivable because respective cultivation conditions are unknown. Therefore the biodiversity of treponemes was only appreciated recently by applying comparative 16S rRNA sequence analysis. Treponemes are mainly representatives of the gastrointestinal autochthonal flora, especially in termites, but they have also been described in swine and cattle. On the other hand treponemes are involved in different infectious diseases, the most well known being syphilis in humans or venereal spirochetosis in rabbits. Furthermore, treponemes are associated with several infectious periodontal diseases, e.g. gingivitis or periodontitis, where they can be detected regularly. Culture has not been successful for most of the oral treponemes, so the major part can only be identified by their 16S rRNA sequence. Similar to these oral disorders treponemes are also associated with digital dermatitis (DD), a chronic inflammatory disease of the bovine skin, where different treponemal phylotypes were found in large numbers. Treponema brennaborense was first identified and isolated in DD biopsies. Unravelling the pathogenic potential and aetiological significance of treponemes in chronic infectious diseases like peridontitis or DD remains a costly task. Although treponemes can be frequently detected in such lesions, it is often unclear to what extent treponemes are involved in pathogenesis of these diseases. The possession of various virulence features like high motility, the ability to adhere and invade as well as to cause cytopathic effects in eukaryotic cells are highly indicative of the aetiological relevance of treponemes.     

Integration of word meaning and world knowledge in language comprehension

Although the sentences that we hear or read have meaning, this does not necessarily mean that they are also true. Relatively little is known about the critical brain structures for, and the relative time course of, establishing the meaning and truth of linguistic expressions. We present electroencephalogram data that show the rapid parallel integration of both semantic and world knowledge during the interpretation of a sentence. Data from functional magnetic resonance imaging revealed that the left inferior prefrontal cortex is involved in the integration of both meaning and world knowledge. Finally, oscillatory brain responses indicate that the brain keeps a record of what makes a sentence hard to interpret.     

High prevalence of treponemes in bovine digital dermatitis-a molecular epidemiology

To validate the epidemiology of Treponema spp. associated with digital dermatitis (DD) a large number of DD samples (n=56) were examined by DNA-DNA dot blot analyses using oligonucleotide probes specific for phylogenetic group I-VII of oral treponemes and DD-associated phylotypes DDKL-4, DDKL-12 and DDKL-20 as well as for T. brennaborense and T. socranskii. Positive hybridisation results were obtained for phylogenetic groups I, II and IV and phylotypes DDKL-4 and DDKL-12. While phylotype DDKL-4 was detected in 100% of the samples treponemes belonging to phylogenetic group TRE I, TRE II and TRE IV were prevalent in nearly 80% of the samples and phylotype DDKL-12 was detected in 66.1% of the samples. Analysis of Treponema groups present concurrently in the same sample revealed that a combination of TRE I-TRE II-TRE IV-DDKL-4 was most prevalent and could be detected in up to 71% of the samples. These data indicate that this combination of different Treponema spp. seems to be the most important one in the pathogenesis of DD. In contrast, T. brennaborense originally isolated from DD material this treponeme was not detected in any of the samples clearly indicating that this species is not absolutely associated with DD and therefore may represent only an incidental treponeme. Fluorescence in situ hybridisation (FISH) obviously highlights the invasive character of DD-associated treponemes. Mainly treponemes belonging to phylogenetic group TRE I and phylotype DDKL-4 were detected in high numbers compared to the total number of bacteria and also in deeper layers of the epithelium at the transition of unaffected and affected tissue. Our results confirm a high prevalence and diversity of Treponema spp. in DD lesions. In addition, our data indicate that certain combinations of Treponema spp. are detected much more frequently than others. Furthermore, Treponema spp. appears at the interface between healthy and diseased tissue underlining their importance for the pathogenesis of DD.     

Biotransformation of the Insecticide Lindane by the White Rot Basidiomycete Phanerochaete chrysosporium

Biotransformation of the insecticide lindane by the white rot basidiomycete Phanerochaete chrysosporium has been investigated in liquid cultures. Some polar metabolites and carbon dioxide were produced from the pesticide. Among the metabolites identified were tetrachlorocyclohexene, tetrachlorocyclohexene epoxide and tetrachlorocyclohexenol. When used as a substrate, tetrachlorocyclohexene was also converted by the fungus to tetrachlorocyclohexenol, polar metabolites and carbon dioxide. Three incubation conditions leading to low and high peroxidase production were assayed. Data from these experiments, as well as in-vitro incubations with purified enzymes, ruled out any involvement of the peroxidases in lindane biotransformation and mineralization. Moreover, 1-aminobenzotriazole (a P450 inactivator) drastically reduced pesticide metabolism. Conversely, phenobarbital (a P450 inducer) did not significantly increase lindane breakdown.     

Bacterial diversity studied by next‐generation sequencing in a mature phototrophic Navicula sp‐based biofilm promoted into a shrimp culture system

The bacterial diversity of a phototrophic biofilm used as nutrient‐recycler into a shrimp aquaculture system and as direct food‐source for shrimp was studied by next‐generation sequencing, considering the 16S rDNA and metagenomics sequence classification using exact alignments. Biofilm was promoted by the modification of cabon:nitrogen ratio and by the addition of the diatom Navicula sp. as promoter. Results revealed a wide diversity of bacteria thriving into the biofilm; most of the bacteria detected in the biofilm belonged to the Proteobacteria (47%), Chlamydiae/Verrucomicrobia (11%), Bacteriodetes (8%), Planctomycetes (5%) Phylum. Species involved in the decomposition of organic matter, nitrogenous‐ and sulfurous metabolites were detected; moreover, filamentous species known as biomass‐bulking enhancers and producers of adhesin‐like compounds were also detected. Surprising results were also obtained by detecting both, strictly anaerobic and aerobic bacteria involved into the metabolism of nitrogenous compounds. Other species not belonging to the marine environment were also detected, but their role is unclear. Finally, the detection of most of these species may constitute a first case report for a phototrophic biofilm. The results suggest an important role of bacteria in this type of biofilm and a complex microbial‐interaction network.     

Global patterns of predator diversity in the open oceans

The open oceans comprise most of the biosphere, yet patterns and trends of species diversity there are enigmatic. Here, we derive worldwide patterns of tuna and billfish diversity over the past 50 years, revealing distinct subtropical "hotspots" that appeared to hold generally for other predators and zooplankton. Diversity was positively correlated with thermal fronts and dissolved oxygen and a nonlinear function of temperature (approximately 25 degrees C optimum). Diversity declined between 10 and 50% in all oceans, a trend that coincided with increased fishing pressure, superimposed on strong El Ni?o-Southern Oscillation-driven variability across the Pacific. We conclude that predator diversity shows a predictable yet eroding pattern signaling ecosystem-wide changes linked to climate and fishing.     

Evidence for the effect of learning on timing of reproduction in blue tits

We experimentally show that in blue tits (Parus caeruleus) egg-laying date is causally linked to experience in the previous year. Females that received additional food in the nestling period in one year laid eggs later in the next year compared with the control birds, whatever the degree of synchronization with the natural food abundance in the previous year. As a result, they raised their brood much later than the peak period of nestling food availability in the next year. The response to experience is adaptive for blue tits, which live in heterogeneous habitats where the peak period of food varies, but once settled will breed at the same location for life.     

Reliable detection of the fungal pathogenfusarium oxysporum f.sp.albedinis, causal agent of bayoud disease of date palm, using molecular techniques

Bayoud, caused by the soilborne fungusFusarium oxysporum f.sp.albedinis (FOA), is the most serious disease of date palm. Since the disease is located in the North African countries of Morocco and Algeria, and advancing steadily eastwards, the ultimate goal is to prevent spread of the pathogen to other date-growing areas in the region and farther afield. Molecular diagnostic techniques have been developed for detection of FOA. In view of the fact that the fungus does not exist in Israel, DNA of FOA was obtained to determine the reliability of these methods for diagnostic purposes. Random amplified polymorphic DNA was not reliable enough for differentiation between FOA and various pathogenic and saprophyticFusarium isolates. However, the polymerase chain reaction utilizing FOA-specific primers was accurate and enabled amplification of a unique band specific to FOA DNA alone, and not that of the other tested pathogenic and saprophyticFusaria. The availability of a rapid and reliable diagnostic tool for detection of FOA will enable the Plant Protection and Inspection Services of the Israel Ministry of Agriculture to test date palm tissue for the presence of the pathogen. Contribution no. 513/00 from the Inst. of Plant Protection, ARO, The Volcani Center, Bet Dagan, Israel.     

Increased nitrogen-use efficiency of a short-rotation poplar plantation in elevated CO(2) concentration

We estimated nitrogen (N) use by trees of three poplar species exposed for 3 years to free air CO(2) enrichment (FACE) and determined whether the CO(2) treatment affected the future N availability of the plantation. Trees were harvested at the end of the first 3-year rotation and N concentration and content of woody tissues determined. Nitrogen uptake of fine roots and litter was measured throughout the first crop rotation. The results were related to previously published variations in soil N content during the same period. We estimated retranslocation from green leaves and processes determining N mobilization and immobilization, such as mineralization and nitrification, and N immobilization in litter and microbial biomass. In all species, elevated CO(2) concentration ([CO(2)]) significantly increased nitrogen-use efficiency (NUE; net primary productivity per unit of annual N uptake), decreased N concentration in most plant tissues, but did not significantly change cumulative N uptake by trees over the rotation. Total soil N was depleted more in elevated [CO(2)] than in ambient [CO(2)], although not significantly for all soil layers. The effect of elevated [CO(2)] was usually similar for all species, although differences among species were sometimes significant. During the first 3-year rotation, productivity of the plantation remained high in the elevated [CO(2)] treatment. However, we observed a potential reduction in N availability in response to elevated [CO(2)].     

Making the user visible: analysing irrigation practices and farmers’ logic to explain actual drip irrigation performance

The actual performance of drip irrigation (irrigation efficiency, distribution uniformity) in the field is often quite different from that obtained in experimental stations. We developed an approach to explain the actual irrigation performance of drip irrigation systems by linking measured performances to farmers’ irrigation practices, and these practices to the underlying logic of farmers who operate these systems. This approach was applied to 22 farms in Morocco. Four sets of variables helped explain the gap between the actual irrigation performance and the performance obtained in experimental conditions: (1) farmers have agro-economic motivations or want to improve their social status, and for them, irrigation performance is at best an intermediate objective. (2) Irrigation performance is not a static value, but a rapidly evolving process, related to the (perceived) ability of farmers to change irrigation practices and renew irrigation equipment, but also to farmers’ aspirations. (3) The social network of farmers, supporting the introduction and use of drip irrigation, determines how farmers may share experience, information and know-how related to drip irrigation. (4) Today, there is no social pressure to irrigate carefully to save water; only the state explicitly links the use of drip irrigation to saving water. Making the drip user visible in research and policy studies would lead to more realistic assessments of irrigation performance and draw the attention of policy makers to the actual conditions in which drip irrigation is used, and as a consequence help incorporate ‘saving water’ as an objective for drip irrigation users.