Microbiota accompanying different arbuscular mycorrhizal fungal isolates influence soil aggregation

Arbuscular mycorrhizal fungi (AMF) are key components of ecosystems through their influence on plant communities and ecosystem processes. A major source of information regarding the importance of AMF species richness on process rates are mesocosm experiments using different levels of diversity of AMF as provided by single-species cultures of AMF. Since AMF inocula are generally made available in the form of non-sterile pot culture material, it is possible that AMF symbiosis-associated microbiota are at least partially responsible for some effects hitherto directly attributed to the AMF mycelium. Here, we provide evidence that microbiota associated with single-species cultures of AMF (after long-term pot culture enrichment of 7–8 years) can strongly affect the ecosystem process of soil aggregation. This effect occurred in an AMF isolate specific manner, but in the absence of live and active AMF mycelium. We additionally documented large differences in microbiota communities associated with the different AMF inocula (using PLFA analyses), suggesting that these differences were at least partly responsible for the observed changes in soil aggregation. This result points to AMF–microbiota interactions as a largely unexplored mechanism underlying soil aggregation (and potentially other ecosystem processes). We suggest that a reinterpretation of previous experiments using greenhouse-derived AMF cultures may be necessary, and the need to consider AMF symbiosis-associated microbiota in mechanistic studies of AMF and mycorrhizae in general is emphasized.     

Conserving biodiversity on calcareous grasslands in the Franconian Jura by grazing: a comprehensive approach

Calcareous grasslands, as extraordinarily species-rich and diverse habitats of northern and central Europe, need some management for their long-term conservation. Traditionally, they have been used as pastures, mainly with sheep, but goats are important, because they mainly browse and climb rocks. This study presents a comprehensive approach to the conservation of these sites, including the requirements of shepherds, which were obtained by a questionnaire, together with autecological information on the habitat requirements of species. Grazing is a central option, which has to be regulated in timing, intensity and spatial distribution, to gain optimum results. Nevertheless, local regulations must consider the requirements of the shepherds regarding infrastructure and social conditions, so that grazing remains practicable. Additionally, sheep-farming on conservation sites is presently unprofitable and therefore needs financial support. This support is supplied by state subsidies in Bavaria (Vertragsnaturschutzprogramm), and in the study area by a lamb-meat sales premium, which allows the shepherds to charge higher prices for lamb-meat produced under the premium regulations. The success of the overall strategy is only possible given a well adjusted interplay of influencing factors.     

Biogenetic studies in Syringa vulgaris L.: synthesis and bioconversion of deuterium-labeled precursors into lilac aldehydes and lilac alcohols

Syringa vulgaris L. inflorescences were fed with aqueous solutions of regioselectively deuterated compounds assumed to be precursors of lilac aldehyde and lilac alcohol, respectively. Volatiles were extracted by stir bar sorptive extraction (SBSE) and analyzed using enantioselective multidimensional gas chromatography/mass spectrometry (enantio-MDGC/MS); deuterium-labeled lilac aldehydes and lilac alcohols were separated from unlabeled stereoisomers on a fused silica capillary column, coated with heptakis(2,3-di-O-methyl-6-O-tert-butyldimethylsilyl)-beta-cyclodextrin (DIME-beta-CD) (30%) in SE 52 (70%), as the chiral stationary phase. Feeding experiments with [5,5-(2)H(2)]mevalonic acid lactone 22 and [5,5-(2)H(2)]deoxy-d-xylose 23 indicate that the novel mevalonate independent 1-deoxy-d-xylose 5-phosphate/2C-methyl-d-erythritol 4-phosphate pathway is the dominant metabolic route for biosynthesis in lilac flowers. Additionally, bioconversion of deuterium-labeled d(5)-(R/S)-linalool 3, d(6)-(R)-linalool 21, d(5)-(R/S)-8-hydroxylinalool 6, d(5)-(R/S)-8-oxolinalool 7, d(5)-lilac aldehydes 8-11 and d(5)-lilac alcohols 12-15 into lilac during in vivo feeding experiments was investigated and the metabolic pathway is discussed. Incubation of petals with an aqueous solution of deuterated d(5)-(R/S)-linalool 3 indicates an autonomic terpene biosynthesis of lilac flavor compounds in the flower petals of lilac.     

Beschreibung des Verlaufs der Stickstoffaufnahme von Kohlrabi (Brassica oleracea convar. acephala var. gongylodes L.) mit Hilfe von Wachstumsstadien und eines empirischen Wachstumsmodells

Nitrogen uptake of kohlrabi, estimated by growth stages and an empirical growth model Some fertilizer recommendation systems for field vegetables are based on estimated nitrogen uptake curves. The estimation of nitrogen uptake should be as accurate as possible. Therefore 3 estimation methods and their accuracy (standard error of difference between measured and estimated values, sd) are compared. Comparisons were carried out with measured nitrogen uptake curves of kohlrabi (Brassica oleracea var. gongylodes L.) from 16 field experiments. The use of observed growth stages resulted in the smallest estimation error (sd = 14 kg N · ha^?1). This method is recommendable because it is accurate and easy to use. Estimations by applying an empirical nitrogen uptake model (sd = 16 kg N · ha^?1) are more complicated. The estimation based on time after planting is easy to use but showed the largest estimation error (sd = 28 kg N · ha^?1).     

Comparing the potential effectiveness of conservation planning approaches in central North Carolina, USA

We compared four approaches to conservation site selection to protect forest biodiversity in the Triangle Region of North Carolina, USA. Using biological inventory data and an inventory-based conservation plan as benchmarks, we evaluated the potential effectiveness of a focal species plan and three “simple” plans (large forested patches, close to wetlands and riparian areas, diverse forest types). Effectiveness was measured in three ways: the number of inventory elements captured at least once by the plan (representation), the total number of inventory elements captured (completeness), and the proportion of land in the inventory-based plan included (overlap). We further examined the potential effectiveness of the simple plans by calculating their overlap with land identified by the focal species approach. The simple and focal species plans did not differ markedly in terms of representation, but diverged when completeness and overlap were considered. Although representation rates for all four plans were relatively high, lower rates for completeness and overlap raise concerns about long-term viability. The simple plans did not identify the same lands as the focal species plan, and are thus unlikely to provide appropriate habitat for the focal species. Each approach we tested failed to capture some subset of species and communities, highlighting the importance of explicit conservation targets and consideration of ecological processes. Forced to act quickly and with little data, our findings suggest using initially a set of complementary simple plans, each focused on a different habitat type. This should be considered a stopgap measure, however, while more sophisticated plans are constructed, defining explicit conservation targets and considering ecological processes.     

Constituents in evening primrose oil with radical scavenging,cyclooxygenase, and neutrophil elastase inhibitory activities

Cold-pressed, non-raffinated evening primrose oil was found to contain lipophilic radical scavengers. A highly enriched fraction of these compounds could be obtained from the oil by extraction with aqueous ethanol and subsequent liquid-liquid partitioning with petroleum. LC-DAD-MS analysis revealed that the fraction contained three aromatic compounds with identical UV and ESI-MS spectra. The compounds were isolated by RP-HPLC and their structures established by chemical and spectroscopic means as 3-O-trans-caffeoyl derivatives of betulinic, morolic, and oleanolic acid. The morolic acid derivative was a new compound. The three esters exhibited pronounced radical scavenging activity against the stable 2,2-diphenyl-1-picrylhydrazyl radical and were potent inhibitors of neutrophil elastase and cyclooxygenase-1 and -2 in vitro. Commercial samples of evening primrose oils contained only traces of these lipophilic antioxidants.     

Ileal Peyer's patches in experimental infections of calves with rotaviruses and enterotoxigenic Escherichia coli: a light and electron microscopic and enzyme histochemical study

The effect of rotaviruses and enterotoxigenic Escherichia coli administered in various sequences to cesarean-derived, colostrum-deprived calves was studied using light and electron microscopy. The structure of the lymphoid tissue in the ileum, the number of mitoses in the crypts, number of intraepithelial lymphocytes, and enzyme histochemistry (alkaline phosphatase, acid phosphatase, succinic dehydrogenase, beta-galactosidase, and leucinaminopeptidase) of the ileal dome epithelium were evaluated. The area of lymphoid follicles in Peyer's patches of the ileum was investigated morphometrically. Monoinfections with either rotavirus or enterotoxigenic E. coli induced a significant increase in lymphoid follicle area, but did not affect dome epithelial cells. Dual infections did not consistently affect the follicle area, but the number of intraepithelial lymphocytes and the mitotic indices exceeded those of comparable monoinfections. Changes in activity of enzymes in the ileal dome epithelial area were minor.     

The biochemical mechanism of action of the dinitroaniline herbicide oryzalin

Dinitroaniline herbicides such as oryzalin (3,5-dinitro-N⁴,N⁴-dipropylsulfanilamide) disrupt mitosis in the meristematic cells of seedling plants by inhibiting the formation of microtubules. For further understanding of the biochemical mechanism of action of oryzalin, laboratory analyses with isolated plant tubulin must be employed. Plant tubulin from flagella of the alga Chlamydomonas was isolated and purified. This tubulin was incubated with [¹⁴C]oryzalin, and free oryzalin was separated from oryzalin bound to plant tubulin by miniature DEAE-cellulose chromatography. Scatchard analysis predicts a molar ratio of oryzalin bound to plant tubulin of 1.0 ± 0.1 when oryzalin is incubated with plant tubulin for 30 min at pH 6.9 and 25°C. The association constant for the oryzalin-tubulin complex is 2.08 ± 0.08 × 10⁵M^?1 at 25°C. The thermodynamic values for the formation of the oryzalin-tubulin complex at 25°C are ΔG^o = ?7.25 ± 0.02 kcal mol^?1, ΔH^o = 6.5 ± 0.2 kcal mol^?1, and ΔS^o = 46 ± 2 cal mol^?1 deg^?1 (mean ± standard error). Oryzalin has little or no affinity for intact microtubules, previously denatured plant tubulin, actin, bovine serum albumin, calmodulin, ferredoxin, trypsin, or urease, indicating oryzalin is specific for the biologically active conformation of plant tubulin. Oryzalin binds to plant tubulin to form a complex that may be incapable of polymerizing into microtubules.     

The present epidemiological status of African swine fever

At present, African swine fever (ASF) persists as an enzootic infection both on the African continent and in Europe (Portugal, Spain, and Sardinia). The recent outbreaks of ASF in Belgium and in the Netherlands have again demonstrated the threat of this disease to the swine population in Germany. The main reasons for this threat are the great tenacity of this virus and its stability in meat and meat products together with an immense tourism into these enzootic areas. Epizootiological peculiarities, such as virus replication in ticks and inapparent infections in wild boars are the reason why eradication of the disease has failed so far, especially when pigs are allowed to roam the countryside.     

Comparative analysis of monoclonal antibodies against pestiviruses: report of an international workshop

Thirty-three pestivirus strains were grown in cell culture and characterized by immunostaining with 19 monoclonal antibodies (MAbs) raised against hog cholera virus (HCV), with 42 MAbs against bovine viral diarrhoea virus (BVDV) and with 13 MAbs against border disease virus (BDV). Seven MAbs reacted with all pestivirus strains tested, eight MAbs detected only the seven HCV strains, three detected only the 16 BVDV strains. No MAb was found that was specific for BDV. BVDV and BDV strains were broadly cross-reactive with the MAbs, indicating a close relationship between these two species, whereas HCV strains were characterized as distinct from BVDV and BDV.