Search

The genus Erebia comprises numerous species in Europe. Due to preference of cold environments, most species have disjunct distributions in the European mountain systems. However, their biogeographical patterns may differ significantly. The Bright-eyed ringlet Erebia oeme is widespread in high-altitude grasslands of the European high mountains, hence showing a disjunct distribution pattern. Over its distribution, E. oeme shows high morphological variability indicating pronounced intraspecific differentiation. We analysed two mitochondrial (COI, Cytb) and eight nuclear markers as well as the Wolbachia surface protein-coding gene (WSP). A total of four lineages were identified: two Balkan lineages, one Slovenian lineage as well as one lineage containing all other individuals (Alps, Massif Central, Pyrenees). COI data only indicate a fifth lineage in the southern Carpathians. The region of origin of E. oeme is most likely the western Balkans. From here, E. oeme spread to the eastern Balkan area and further to the southern Carpathians as well as to Slovenia, from where it rapidly crossed the Alps to Massif Central and Pyrenees. Wolbachia was found to be highly prevalent with multiple strains, partly within one population. However, recent Wolbachia impact on the mitochondrial DNA and consequently influence on the intraspecific genetic structure was not detected. [ABSTRACT FROM AUTHOR]

Crop wild relatives (CWR) represent valuable sources of traits that can enhance the abiotic and biotic stress tolerance of crops. Due to climate change and expansion of land use, they may suffer from population decline, which increases the risk of losing these resources. The in situ conservation of CWR is receiving growing attention to preserve their intraspecific diversity. In contrast to the safeguarding of seeds ex situ, the preservation of taxa in their natural habitat facilitates the development of new adaptations to changing environmental conditions. However, studies aiming at the establishment of their in situ conservation are rare. Therefore, we identified and genotyped Helosciadium nodiflorum occurrences in Germany. Helosciadium nodiflorum is an endangered CWR of cultivated celery (Apium graveolens). For 20 occurrences the number of individuals, the number of sexually reproducing individuals, and potential threats were recorded. Genetic differences were examined using 17 newly developed simple sequence repeats (SSR). Population genetic analyses, like the inference of the compositional genetic differentiation, of population structure, and a Discriminant Analysis of Principal Components were conducted. The analyses revealed that most occurrences were genetically distinct. Geographically closely located populations are often also genetically more similar. Several populations revealed a composite genome indicative of hybridizations between distinct populations. Populations that experienced fixation were also identified. Based on the genetic diversity, the location in different ecogeographic units, and the support of local stakeholders, we recommend the establishment of 15 genetic reserves for H. nodiflorum in Germany. [ABSTRACT FROM AUTHOR]

Four silica-based acaricides were examined in laboratory tests for their effectiveness against poultry red mite, Dermanyssus gallinae. All acaricides resulted in 100% mite mortality. Two groups of active ingredients could be differentiated. The products Silicosec® and Ewazid®, based on naturally occurring diatomaceous earth (DE), killed 100% of adult D. gallinae within 48 h exposure time. The time to kill 50% of the mites (LT50) was calculated to be 31.7 and 34.9 h, respectively. The other two products, containing aggregates and agglomerates of pyrogenic synthetic amorphous silicon dioxide as active ingredients, killed the mites in a significantly shorter time: LT50 was 6.3 h for the liquid product Fossil Shield® Instant White and 11.8 h for the powdery product Fossil Shield 90.0 White. This is more remarkable as the quantities of active ingredients used for the DE treatments were several folds higher. The effectiveness of all tested products was also shown in practical tests. A professional company treated five chicken houses on one farm in the Berlin–Brandenburg region with the test products, three houses with Fossil Shield Instant White and one each with Ewazid and Silicosec. Over a period of 46 weeks after stocking, the mite development in the houses was assessed. Only in one of the houses, treated with Fossil Shield Instant White, the mite population remained permanently low. In two houses treated with Fossil Shield Instant White, small mite colonies appeared in week 36, which were controlled by a follow-up spot treatment in week 41. In the houses treated with DE, the first mite colonies appeared 12 weeks after stocking. The number increased continuously over the experimental period and in week 31 after stocking there were clearly visible colonies (2–3 cm diameter) and the first mites could also be detected on the chicken eggs. At this time both houses were treated again with a follow-up spot-treatment, which only led to a slight improvement in one house and to a stabilization of the infestation in the other house. In week 41, large mite colonies were detected in both houses. A spot treatment at this point was ineffective in reducing the infestation. The tests showed faster acaricidal action of the products with the synthetic active ingredients compared to the natural DE-based products. This matches the shorter killing times under laboratory conditions. The experiments in a commercial chicken farm showed that it is possible to control the mite population for a period of 46 weeks by using physically effective SiO2-based products. These products are therefore an effective alternative to the use of chemical acaricides. [ABSTRACT FROM AUTHOR]

Interactions between bacteria govern the progression of respiratory infections; however, the mechanisms underpinning these interactions are still unclear. Understanding how a bacterial species comes to dominate infectious communities associated with respiratory infections has direct relevance to treatment. In this study, Burkholderia, Pseudomonas, and Staphylococcus species were isolated from the sputum of an individual with Cystic Fibrosis and assembled in a fully factorial design to create simple microcosms. Measurements of growth and habitat modification were recorded over time, the later using proton Nuclear Magnetic Resonance spectra. The results showed interactions between the bacteria became increasingly neutral over time. Concurrently, the bacteria significantly altered their ability to modify the environment, with Pseudomonas able to utilise secondary metabolites produced by the other two isolates, whereas the reverse was not observed. This study indicates the importance of including data about the habitat modification of a community, to better elucidate the mechanisms of bacterial interactions. [ABSTRACT FROM AUTHOR]

We previously showed that purified 1-methoxy-3-indolylmethyl (1-MIM) glucosinolate, a secondary plant metabolite in Brassica species, is mutagenic in various in vitro systems and forms DNA and protein adducts in mouse models. In the present study, we administered 1-MIM glucosinolate in a natural matrix to mice, by feeding a diet containing pak choi powder and extract. Groups of animals were killed after 1, 2, 4 and 8 days of pak choi diet, directly or, in the case of the 8-day treatment, after 0, 8 and 16 days of recovery with pak choi-free diet. DNA adducts [N2-(1-MIM)-dG, N6-(1-MIM)-dA] in six tissues, as well as protein adducts [τN-(1-MIM)-His] in serum albumin (SA) and hemoglobin (Hb) were determined using UPLC–MS/MS with isotopically labeled internal standards. None of the samples from the 12 control animals under standard diet contained any 1-MIM adducts. All groups receiving pak choi diet showed DNA adducts in all six tissues (exception: lung of mice treated for a single day) as well as SA and Hb adducts. During the feeding period, all adduct levels continuously increased until day 8 (in the jejunum until day 4). During the 14-day recovery period, N2-(1-MIM)-dG in liver, kidney, lung, jejunum, cecum and colon decreased to 52, 41, 59, 11, 7 and 2%, respectively, of the peak level. The time course of N6-(1-MIM)-dA was similar. Immunohistochemical analyses indicated that cell turnover is a major mechanism of DNA adduct elimination in the intestine. In the same recovery period, protein adducts decreased more rapidly in SA than in Hb, to 0.7 and 37%, respectively, of the peak level, consistent with the differential turnover of these proteins. In conclusion, the pak choi diet lead to the formation of high levels of adducts in mice. Cell and protein turnover was a major mechanism of adduct elimination, at least in gut and blood. [ABSTRACT FROM AUTHOR]

Main conclusion: This study demonstrates that the application of the PGPB strain, Kosakonia radicincitans enhances a plant’s resistance against phloem-feeding and chewing insects in Arabidopsis thaliana.The plant growth-promoting bacterial strain K. radicincitans DSM 16656 applied to A. thaliana reduced the number of phloem-feeding insects of both the specialist Brevicoryne brassicae and the generalist Myzus persicae. While weight gain of the generalist chewing insect Spodoptera exigua was reduced by 30% on A. thaliana plants treated with K. radicincitans, growth of the specialist caterpillar Pieris brassicae was not affected when compared with caterpillars from control plants. Since generalist and specialist chewing insects responded differentially to PGPB application, the implication of signaling pathways in PGPB mediated changes in plant defense was studied using two signaling pathway mutants impaired in their salicylic acid (npr1-1 mutant) or jasmonic acid (coi1-1 mutant) pathway. We found that the jasmonic acid pathway is relevant for upregulation of aliphatic glucosinolates and suppression of the chewing generalist S. exigua larval growth. Chewing from generalist P. brassicae increased glucosinolate content in A. thaliana leaves mediated via both signaling pathways. However, only in the npr1-1 mutant, which contains the highest aliphatic glucosinolate content, the P. brassicae induced further enrichment of glucosinolates, resulting in a reduction of larval growth. Effects of K. radicincitans on plant resistance could not be explained by changes in glucosinolate contents or composition. Our results demonstrate the distinct role played by K. radicincitans in suppressing insect performance in A. thaliana. [ABSTRACT FROM AUTHOR]

The improvement of micro-milling processes implies the application of advanced analysis and modeling techniques to derive a deeper process understanding. Because of micro-scale effects, monitoring, and measurement systems applied in conventional milling are in most cases not suitable for identifying optimal cutting conditions. Therefore, analytical and mechanical models have been developed in recent years to account for impact factors dominating the micro-milling errors. Within the research presented in this publication, geometric, kinematic, and dynamic models have been adjusted and dimensioned according to the dominating impact factors in micro-milling and have been consolidated to enable for a time-domain simulation. The effect of element size of discretized workpiece and tool as well as the time step size on cutting forces has been evaluated. The accuracy of predicting cutting forces has been investigated and a good agreement of measured and simulated cutting forces has been found. Finally, a mold for a micro-fluidic device has been machined virtually and experimentally to evaluate the accuracy of the integrated models in predicting the final quality of a micro-milled part in terms of surface quality parameters. [ABSTRACT FROM AUTHOR]

Glucosinolates (GS) are secondary plant metabolites comprising different subgroups with opposing effects on human health. Hairy root cultures (HRC) are potent biotechnological tools allowing the biosynthesis of special substances under defined conditions. HRC of Eruca sativa, a brassicaceaous plant, were used to test different strategies to enhance GS levels and to alter the profile. Additional sulphur supply in the nutrient medium increased especially aliphatic GS by 2.7-fold, but also enhanced indole GS by 1.8-fold. Ethephon as well as jasmonic acid as chemical elicitors enhanced only indole GS levels, whereby especially 4-methoxyindol-3-ylmethyl or 1-methoxyindol-3-ylmethyl GS accumulated. Jasmonic acid was used in combination with pulsed electric field treatment as physical elicitor. Already within 24 h, GS levels doubled in treated HRC compared to the control. For estimation of production potency, the GS levels of HRC were compared to contents of aerial and root parts of E. sativa sprouts. HRC showed a distinct GS profile compared to the parent plant with a higher content of indole GS when compared to sprout roots, but overall lower total GS levels. Furthermore, HRC released GS into the culture medium, which could be enhanced by jasmonic acid and pulsed electric field treatment. This could comprise an efficient strategy for a continuous GS production and mining without solvent extraction. [ABSTRACT FROM AUTHOR]

Microbial communities drive biogeochemical cycles through networks of metabolite exchange that are structured along energetic gradients. As energy yields become limiting, these networks favor co-metabolic interactions to maximize energy disequilibria. Here we apply single-cell genomics, metagenomics, and metatranscriptomics to study bacterial populations of the abundant "microbial dark matter" phylum Marinimicrobia along defined energy gradients. We show that evolutionary diversification of major Marinimicrobia clades appears to be closely related to energy yields, with increased co-metabolic interactions in more deeply branching clades. Several of these clades appear to participate in the biogeochemical cycling of sulfur and nitrogen, filling previously unassigned niches in the ocean. Notably, two Marinimicrobia clades, occupying different energetic niches, express nitrous oxide reductase, potentially acting as a global sink for the greenhouse gas nitrous oxide. [ABSTRACT FROM AUTHOR]

Purpose: Radiofrequency catheter ablation of typical atrial flutter can vary largely in duration from patient to patient. The purpose of this work was to determine optimal combination of ablation settings leading to the highest procedural efficacy.Methods: Our retrospective multivariate analysis comprised 448 patients undergoing atrial flutter ablation with nonirrigated 8-mm catheters at 19 clinical centers. Four procedural variables were included in the prognostic model: preset maximum temperature, preset maximum power, catheter-tip material (gold vs. platinum-iridium), and ablation technique (maximum voltage-guided vs. conventional anatomical approach). Univariate and multivariate analyses were performed using the logistic regression (for acute ablation success) and Cox constant proportional hazard models (for cumulative ablation time).Results: Significant multivariate predictors of acute ablation success were a higher preset maximum temperature (odds 1.083 per 1 °C, P < 0.05) and gold-tip catheter (odds 2.096, P < 0.05). Predictors of cumulative ablation time were the maximum voltage-guided ablation technique (hazard ratio 1.856, P < 0.001), higher preset maximum temperature (hazard ratio 1.039 per 1 °C, P < 0.001), and gold-tip catheter (hazard ratio 1.225, P < 0.05). The combination of optimal settings (70 °C, 70 W, gold-tip catheter, maximum voltage-guided technique) increased the acute success rate from 91.7 % (for the entire study cohort) to 100 %, and reduced median cumulative ablation time from 8.3 to 4.3 min, median total procedure duration from 76 to 55 min, and median fluoroscopy time from 14 to 7 min.Conclusions: The combination of maximum voltage-guided gold-tip ablation at 70 °C and 70 W was associated with 100 % ablation success and minimal ablation times for nonirrigated ablation of atrial flutter. [ABSTRACT FROM AUTHOR]

Aggregations of the striped flea beetle Phyllotreta striolata on their crucifer host plants are mediated by volatiles emitted from feeding males. The male-specific sesquiterpene, (6 R,7 S)-himachala-9,11-diene (compound A), was shown previously to be physiologically and behaviorally active, but compound A was attractive only when combined with unnaturally high doses of the host plant volatile allyl isothiocyanate (AITC) in field trapping experiments. This indicated that our understanding of the chemical communication in this species is incomplete. Another male-specific sesquiterpenoid, (3 S,9 R,9a S)-3-hydroxy-3,5,5,9-tetramethyl-5,6,7,8,9,9a-hexahydro-1H-benzo[7]annulen-2(3H)-one (compound G), has been reported from an American P. striolata population. We confirmed the presence of compound G, and investigated its interaction with compound A and AITC in a P. striolata population in Taiwan. Compound G was attractive to Taiwanese P. striolata in laboratory bioassays, but significantly more beetles were attracted to a blend of compounds A and G. Under the same conditions, P. striolata showed no preference for the blend of A and G combined with a range of doses of AITC over the sesquiterpenoid blend alone. The sesquiterpenoid blend was tested further in field trapping experiments and attracted significantly more beetles than traps baited with compound A and ecologically relevant amounts of AITC. We conclude that A and G are components of the male-specific aggregation pheromone of P. striolata in Taiwan, and that the attractiveness of the pheromone is not reliant on the presence of AITC. Our results further indicate that the male-specific sesquiterpenoid blends differ qualitatively between the Taiwanese and American populations of P. striolata. [ABSTRACT FROM AUTHOR]

The legume pod borer, Maruca vitrata, is a pantropical pest on leguminous crops. ( E,E)-10,12-Hexadecadienal, ( E,E)-10,12-hexadecadienol, and ( E)-10-hexadecenal were described previously as sex pheromone components for this nocturnal moth. A blend of these components in a ratio of 100:5:5 attracted males in field trapping experiments in Benin, but not in Taiwan, Thailand, or Vietnam. This finding suggests geographic variation in the pheromone blend between Asian and West African populations of M. vitrata. We, therefore, determined the pheromone compositions of single pheromone glands of females from the three Asian regions and from Benin by gas chromatography-mass spectrometry. Additionally, we compared the responses of males from Taiwan and Benin to calling females and to gland extracts of females from both regions in laboratory no-choice and two-choice assays. Chemical analysis revealed the presence of ( E,E)-10,12-hexadecadienal and ( E,E)-10,12-hexadecadienol, as well as the absence of ( E)-10-hexadecenal in all four populations. The relative amounts of the detected compounds did not vary significantly among the insect populations. The behavioral bioassays showed that Taiwanese and Beninese males were similarly attracted to females from both regions, as well as to their gland extracts. As a result, we did not find geographic variation in the sexual communication system of M. vitrata between West African and Asian insect populations. [ABSTRACT FROM AUTHOR]

Copyright of Gesunde Pflanzen is the property of Springer Nature and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Two cytochrome P450 proteins, CYP79F1 and CYP79F2, are involved in the biosynthesis of aliphatic glucosinolates (GSs) in brassicaceous species. In order to increase aliphatic GS levels in Arabidopsis thaliana hairy root cultures (HRCs) with the aim of biomanufacturing GSs, CYP79F1 and CYP79F2 from either Arabidopsis thaliana or Brassica rapa were first constitutively expressed in stably transformed Arabidopsis plants, and then HRC was induced by additional transformation with Agrobacterium rhizogenes. Gene expression levels and GS profiles were analyzed in HRC in order to validate the impact on aliphatic levels. To estimate the potency of gene transformation on GS content in HRC, GS levels were compared to levels in roots and leaves of transformed plants. According to the data obtained, short-chain aliphatic GSs in plants were raised in three generations after transformation, indicating that expression of transgenes was stable. After HRC induction, transcript levels of CYP79F1 and CYP79F2 rose and short-chain aliphatic GS levels increased by as much as 7-fold compared to the respective HRC wild-type control. However, when compared to levels present in leaves and roots of plants before HRC induction, aliphatic GS levels in HRC remained very low. In addition, expression of CYP79F1 and CYP79F2 also enhanced the content of indole GSs, mainly indol-3-ylmethyl GS and 4-hydroxy-indol-3-ylmethyl GS in HRC. The results presented provide basic information about GS biosynthesis in HRC of Arabidopsis thaliana compared to intact plants, which will help scientists to further optimize GS composition in HRC in the future. [ABSTRACT FROM AUTHOR]

Moringa is a mycorrhizal crop cultivated in the tropics and subtropics and appreciated for its nutritive and health-promoting value. As well as improving plant mineral nutrition, arbuscular mycorrhizal fungi (AMF) can affect plant synthesis of compounds bioactive against chronic diseases in humans. Rhizophagus intraradices and Funneliformis mosseae were used in a full factorial experiment to investigate the impact of AMF on the accumulation of glucosinolates, flavonoids, phenolic acids, carotenoids, and mineral elements in moringa leaves. Levels of glucosinolates were enhanced, flavonoids and phenolic acids were not affected, levels of carotenoids (including provitamin A) were species-specifically reduced, and mineral elements were affected differently, with only Cu and Zn being increased by the AMF. This study presents novel results on AMF effects on glucosinolates in leaves and supports conclusions that the impacts of these fungi on microelement concentrations in edible plants are species dependent. The nonspecific positive effects on glucosinolates and the species-specific negative effects on carotenoids encourage research on other AMF species to achieve general benefits on bioactive compounds in moringa. [ABSTRACT FROM AUTHOR]

Poultry red mite infestation still is an unsolved problem in poultry farms. Legal regulations, residue risks, and resistances limit chemical control of mites. Alternatives to chemical acaricides for control of poultry red mite are silica-based products, which have as a main constituent silicon dioxide. The acaricidal effect is attributed to sorptive properties of the particles, which result in the mite's death by desiccation. In the present study, the acaricidal efficacy of 12 products containing natural or synthetic silica, 9 in powder form, and 3 for liquid application was tested under laboratory conditions. Mite mortality was measured at several intervals and the mean lethal time (LT) determined by Probit analysis after Abbott's correction. The LT values of the products significantly differed (Tukey's HSD p < 0.05). LT values of powdery formulations ranged from 5.1 to 18.7 h and overlapped with those of the fluid ones which ranged from 5.5 to 12.7 h. In order to explain the differences in efficacy of the tested silica products, further characterizations were carried out. X-ray fluorescence, specific surface, cation exchange capacity (CEC), and water absorption capacity (WAC) were measured. Furthermore, electron microscopy was conducted and different products compared. Silicon dioxide content (ranging from 65 to 89 % for powders and 57 to 80 % for fluids) had no significant impact on efficacy, while specific surface and CEC (2.4-23.2 mEq 100 g for powders and 18-30.8 mEq 100 g) were positively and WAC (1.3-4.4 wt% for powders and 3.3-4.8 wt% for fluids) negatively related to the acaricidal efficacy. Influence of these parameters on acaricidal efficacy was significant according to the results of a stepwise regression analysis ( p < 0.01). [ABSTRACT FROM AUTHOR]

1-Methoxy-3-indolylmethyl (1-MIM) glucosinolate, a secondary metabolite of Brassicales species, and its breakdown product 1-MIM alcohol are mutagenic in cells in culture after activation by plant β-thioglucosidase and human sulphotransferase, respectively. In the present study, we administered these compounds orally to mice to study time course, dose dependence, tissue distribution and cellular localization of the 1-MIM DNA adducts formed. We used isotope-dilution ultra-performance liquid chromatography-tandem mass spectrometry to quantify the adducts and raised an antiserum for their immunohistochemical localization. Both compounds formed the same adducts, N-(1-MIM)-2′-deoxyguanosine and N-(1-MIM)-2′-deoxyadenosine, approximately in a 3.3:1 ratio. 1-MIM glucosinolate primarily formed these adducts in the large intestine, with a luminal-basal gradient, probably due to activation by thioglucosidase from intestinal bacteria. 1-MIM alcohol formed higher levels of adduct than the glucosinolate. Unlike after treatment with the glucosinolate, luminal and basal enterocytes were similarly affected in caecum, and liver and stomach were additional important target tissues. Maximal adduct levels were reached 8 h after the administration of both compounds. The hepatic DNA adducts persisted for the entire observation period (48 h), whereas those in large intestine rapidly declined due to cell turnover, as verified by immunohistochemistry. Hepatic adduct formation was focused on the periportal hepatocytes with concomitant depletion of glycogen, p53 activation and p21 induction. Adduct formation in caecum was associated with massive apoptosis, p53 activation and p21 induction, in particular after treatment with 1-MIM alcohol. It remains to be studied whether similar effects occur in humans after the consumption of Brassicales species. [ABSTRACT FROM AUTHOR]

The challenge in the milling of freeform surfaces lies in the enhancement of surface quality as well as the reduction of production time and cost. Freeform surface milling processes have been analysed and contrasted, to identify and quantify the decisive factors that significantly influence the productivity and the workpiece quality. The focus has been on monitoring, simulating and quantifying error sources which affect the manufacturing accuracy. The error sources have been separately examined and modelled so as to assign their proportional impact on product quality. The impact of the interpolation method on the tool path accuracy has been analysed, the dynamic behaviour has been simulated, and the CNC process data and the process forces have been monitored. The monitored and measured data have been synchronized in the time domain for each experimental freeform surface milling process and used as input for geometric machining simulations. To evaluate the virtual machining approach, the quality of the virtual products obtained has been compared to the quality of the real products. Furthermore, the proportion of each considered error source could be related to the deviations measured in particular regions of the machined surface. [ABSTRACT FROM AUTHOR]

Hairy root cultures transformed with Agrobacterium rhizogenes or undifferentiated callus cultures are used for production of plant secondary metabolites. Glucosinolates (GS) are a group of secondary metabolites that produce a variety of bioactive compounds upon hydrolysis. Several studies report the successful production of high concentrations of secondary metabolites in vitro. However, such cultivation methods can significantly change metabolic profiles, and the mechanism behind this to be rarely understood. Therefore, we compared the GS and transcript profiles of Arabidopsis thaliana leaves and roots with hairy root and callus in vitro cultures. Compared to the roots of intact A. thaliana plants, overall, hairy roots contained lower GS levels. In particular, lower quantities of short-chain aliphatic GS were observed and a larger proportion of long-chain aliphatic GS on total content. Corresponding, the transcript levels of most aliphatic biosynthetic genes ( MAM1, CYP79F1, CYP83A1, UGT74C1, and SUR1) were significantly lower in hairy root cultures compared to roots of intact plants. In callus culture, the lowest transcripts levels were detected for overall GS biosynthetic genes with an absence of aliphatic GS. From the indole group, 1-methoxy-indol-3-ylmethyl GS was found to be a major component in hairy root cultures and roots whereas indol-3-ylmethyl GS dominated in leaves and 4-hydroxy-indol-3-ylmethyl GS in callus cultures. Leaves of intact plants contained the highest amounts of GS. Here, aliphatic short-chain GS dominated which was in accordance with transcript levels of aliphatic biosynthetic genes. The study reveals tissue-specific accumulation of GS and transcript pattern in plants distinct from in vitro culture systems. [ABSTRACT FROM AUTHOR]

A liquid chromatography-tandem mass spectrometry (LC-MS/MS) method was developed and validated to determine the concentration of benzyl isothiocyanate (BITC) metabolites in human plasma and urine. In this study, the following BITC metabolites have been considered: BITC-glutathione, BITC-cysteinylglycine, BITC-cysteine, and BITC- N-acetyl- l-cysteine. The assay development included: (1) synthesis of BITC conjugates acting as reference substances; (2) sample preparation based on protein precipitation and solid-phase extraction; (3) development of a quantitative LC-MS/MS method working in the multiple-reaction monitoring mode; (4) validation of the assay; (5) investigation of the stability and the reactivity of BITC conjugates in vitro; (6) application of the method to samples from a human intervention study. The lower limits of quantification were in the range of 21-183 nM depending on analyte and matrix, whereas the average recovery rates from spiked plasma and urine were approximately 85 and 75 %, respectively. BITC conjugates were found to be not stable in alkaline buffered solutions. After consumption of nasturtium, containing 1,000 μM glucotropaeolin, the primary source of BITC, quantifiable levels of BITC-NAC, BITC-Cys, and BITC-CysGly were found in human urine samples. Maximum levels in urine were determined 4 h after the ingestion of nasturtium. With regard to the human plasma samples, all metabolites were determined including individual distributions. The work presented provides a validated LC-MS/MS method for the determination of BITC metabolites and its successful application for the analysis of samples collected in a human intervention study. [Figure not available: see fulltext.] [ABSTRACT FROM AUTHOR]

Copyright of Gesunde Pflanzen is the property of Springer Nature and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Oscillatory measurements are often used to explore the nonlinear response of materials, with recently a strong focus on using large amplitude oscillatory experiments. However, the superposition of an oscillatory motion onto a steady-state shear flow is a method where the kinematic history experienced by the sample is simpler. Such a superposed oscillation can be applied either orthogonal or parallel to the main flow direction. Both superposed deformation modes can now be achieved on rotational rheometers equipped with a force-rebalanced transducer, the orthogonal mode requiring a minor modification to the control loop of the normal force. In the present work, the nonlinear properties of a wormlike micellar (WLM) solution are studied. The results are compared with the predictions of the Giesekus model, which is chosen both for its capability to describe the WLM response and for being one of the simplest continuum models that incorporate an anisotropic microstructure. From the fluid response in the homogeneous flow regime, a rate-dependent relaxation time and a rate-dependent plateau modulus can be derived. The latter provides insight into the structural anisotropy during flow at short length scales, which in this case is isotropic. Further analysis of the superposition moduli can be used to separate and quantify the effects of flow on the reptation and breaking of the chains. In the shear-banding regime, the orthogonal moduli show a weaker dependence on shear rate compared to the predictions of the Giesekus model, yet they remain sensitive to changes in the shear-banded state. [ABSTRACT FROM AUTHOR]

Plant growth-promoting bacteria (PGPB) affect plant cellular processes in various ways. The endophytic bacterial strain Enterobacter radicincitans DSM 16656 has been shown to improve plant growth and yield in various agricultural and vegetable crops. Besides its ability to fix atmospheric nitrogen, produce phytohormones, and solubilize phosphate compounds, the strain is highly competitive against native endophytic organisms and colonizes the endorhizosphere in high numbers. Here, we show that E. radicincitans inoculation of the noncrop plant Arabidopsis thaliana promotes plant growth. Furthermore, high performance liquid chromatography (HPLC) analysis revealed that bacterial inoculation slightly decreased amounts of aliphatic glucosinolates in plant leaves in a fast-growing stage but increased these compounds in an older phase where growth is mostly completed. This effect seems to correlate with developmental stage and depends on the nitrogen requirement. Additionally, nitrogen deficiency studies with seedlings grown on medium containing different nitrogen concentrations suggest that plant nitrogen demand can influence the intensity of plant growth enhancement by E. radicincitans. This endophyte seems not to activate stress-inducible mitogen-activated protein kinases (MAPKs). Analyzing transcription of the defense-related genes PR1, PR2, PR5, and PDF1. 2 by quantitative real time polymerase chain reaction (qPCR) revealed that E. radicincitans DSM 16656 is able to induce priming via salicylic acid (SA) or jasmonate (JA)/ethylene (ET) signaling pathways to protect plants against potential pathogen attack. [ABSTRACT FROM AUTHOR]

Copyright of Gesunde Pflanzen is the property of Springer Nature and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The concept of ecological succession has been frequently applied in the study of ancient reefs. Whereas Paleozoic and Mesozoic reefs are commonly thought to reveal an autogenic primary-climax zonation, patterns in Neogene and Quaternary reefs are much more diverse. Here, we describe a well-preserved late Pleistocene coral reef from Dahab on Sinai Peninsula (Egypt), which shows a distinct zonation that resembles an ecological succession. In contrast to classical examples of ecological successions, species composition, paleoenvironmental conditions, and coral biodiversity of the Dahab reef indicate an allogenic, sea-level controlled community change, from marginal marine to reef slope and back reef. A review of the literature confirms that autogenic, short-term successions are virtually absent in Quaternary reefs. We predict that long generation times of corals make it unlikely that classical autogenic successions develop in reefs at all, unless environmental conditions are unusually stable. [ABSTRACT FROM AUTHOR]

Copyright of Gesunde Pflanzen is the property of Springer Nature and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Background: Atrial fibrosis and its spatial heterogeneity are regarded as a substrate for the perpetuation of atrial arrhythmias. During collagen synthesis and degradation, collagen propeptides and telopeptides are released into the blood. This study tested the hypothesis that serum markers of collagen turnover correlate with atrial fibrosis. Methods: We prospectively included 28 patients in sinus rhythm undergoing cardiac surgery. Plasma concentrations of the carboxy- and amino-terminal propeptide of procollagen type-I (PICP and PINP) and type-III (PIIINP), and the C-terminal telopeptide of type-I collagen (ICTP) were determined. Interstitial fibrosis of left ( n = 10) and right atrial appendages ( n = 28) was analyzed histologically. Results: We found a correlation between left and right atrial fibrosis ( r = 0.79, p < 0.01). Interestingly, the higher the interstitial collagen content, the higher was the spatial heterogeneity of fibrosis ( r = 0.90, p < 0.001). However, PICP, PIIINP, and ICTP were not correlated to left or right atrial collagen content, or to the spatial heterogeneity of atrial fibrosis. There was a weak and even negative correlation between the serum PINP concentration and the degree of fibrosis in both the left and the right atrium ( r = −0.65 ( p = 0.04) and r = −0.42 ( p = 0.03), respectively). Conclusions: A high degree of interstitial atrial fibrosis indicates a high degree of spatial heterogeneity of interstitial collagen. Although serum PICP is known to be correlated with ventricular fibrosis, this and other serum markers of collagen turnover (PINP, PIIINP, and ICTP) do not directly reflect atrial fibrosis in patients with severe cardiac disease. [ABSTRACT FROM AUTHOR]

The effects of yeast extract and selected polysaccharide elicitors on secondary metabolite production, particularly of anthocyanin and phenolic acid, in cell suspension cultures of Vitis vinifera were investigated. All elicitors either maintained or promoted cell growth in culture. Overall, secondary metabolite production in V. vinifera cell suspension cultures responded differently to different elicitors. Chitosan, pectin, and alginate enhanced production of anthocyanin within 13 days of culture with levels of 2.5-, 2.5-, and 2.6-fold increase, respectively, over that of control. Chitosan, alginate, and gum arabic significantly promoted accumulation of phenolic acids, particularly 3- O-glucosyl-resveratrol, in V. vinifera cultures, as well as in the culture medium. Intracellular phenolic acid production was significantly enhanced by alginate and chitosan, with 1.7- and 1.5-fold levels, respectively, of that of control. Extracellular phenolic acid production was also significantly increased in the presence of chitosan and gum arabic, with levels of 3.3- and 1.7-fold higher, respectively, than those of control. In addition, DPPH (1,1-diphenyl-2-picrylhydrazyl) radical scavenging activity was enhanced in the presence of elicitors, and this was positively correlated with increased accumulation of anthocyanin in V. vinifera cell suspension cultures. [ABSTRACT FROM AUTHOR]

Glucosinolates (GS) are the main secondary metabolites in brassicaceous plants that play an important role in plant defense and plant-insect communication. GS biosynthesis in plants and their accumulation may be influenced by biotic and abiotic stressors from the environment. In the present study, GS levels in broccoli plants, Brassica oleracea var. italica Plenck, grown under different water status conditions of soil-well-watered, drought and waterlogged-were determined after two aphid species, the specialist Brevicoryne brassicae (L.) and the generalist Myzus persicae (Sulzer), had fed on them for 7 days. High-performance liquid chromatography analysis revealed that GS levels were significantly induced after B. brassicae had fed on B. italica plants grown for 2 weeks under the various water status conditions. No significant differences were determined between GS induction in the three treatments. In contrast, the induction of GS after M. persicae had fed on the plants depended greatly on water stress levels. GS content in well-watered plants increased more significantly than in plants grown under drought conditions. Feeding by M. persicae did not increase GS levels when plants were grown under waterlogged conditions. The lowest plant growth were found in M. persicae-infested plants for all three water treatments, and measurements of GS showed that the induction of GS by M. persicae decreased in line with the reduction in infested plant growth. GS induction by B. brassicae did not alter remarkably following change in plant growth under water stress. Only one of the five glucosinolates detected, the aliphatic GS 4-methylsulfinylbutyl, remained unchanged after feeding of both, M. persicae and B. brassicae, on plants under water stress. Variation in GS levels was mainly observed for the induction of indolyl GS due to aphid herbivory, but changes in indol-3-ylmethyl GS were not always consistent with the induction of other indolyl GS. [ABSTRACT FROM AUTHOR]

Glucosinolates (GSs) are part of a two-component defence system, characteristic for the Brassicales, including the model species Arabidopsis thaliana (L.) Heynh. The defence activity of GSs is associated with different side chain structures. The AOP genes are central in side-chain modification. AOP2 mediates formation of alkenyl GS from a methylsulfinyl precursor, whereas AOP3 catalyzes production of hydroxy-alkyl GSs from the same precursor. Although several studies have assessed the role of GSs in plant defence, the function of specific aliphatic GSs in plant defence is still not clarified. Structural different GSs may influence insect herbivores differentially. We created a set of plant lines derived of a cross between two A. thaliana accessions, Gie-0 × Sap-0, which dominantly accumulate either 3-methylsulfinylpropyl GS or 3-hydroxypropyl GS. The generalist Spodoptera exigua (Hübner) (Lepidoptera: Noctuidae) and the crucifer-specialist Pieris brassicae (L.) (Lepidoptera: Pieridae) were used as model insects, to study effects of individual aliphatic GSs on lepidopteran herbivores with a different feeding specialization. However, the experiments revealed that weight gain of S. exigua and P. brassicae third and fourth-larval instars was similar on both chemotypes. But leaf consumption of the generalist was higher on 3-methylsulfinylpropyl-producing lines with low GS levels (23.2 μmol g) than on 3-hydroxypropyl-producing lines that contained a more than twofold higher amount of GSs (60 μmol g). In contrast, no differential effects of non-hydroxylated and hydroxylated GSs were found on the specialist P. brassicae. Our study indicates that there is no simple relationship between GS content and insect responses. [ABSTRACT FROM AUTHOR]

Plant cell cultures provide a large potential for the production of secondary metabolites. Through the application of different physical and chemical cell stress factors, we investigated the production of the secondary metabolites in plant cell cultures. The effects of pulsed electric field (PEF) and ethephon on growth and secondary metabolism, particularly anthocyanins and phenolic acids synthesis, were investigated by using suspension culture of Vitis vinifera L. cv. Gamay Fréaux as a model system. Anthocyanins were measured by spectrophotometer and extracellular phenolic acids were determined by high-performance liquid chromatography. The compounds were identified by liquid chromatography-mass spectrometry and nuclear magnetic resonance. After the treatments with PEF and ethephon, the concentrations of anthocyanins and phenolic acids in cell culture were higher than in the control, without loss of biomass. The combination of PEF treatment and ethephon improved secondary metabolites formation. Production levels of extracellular phenolic acids, 3- O-glucosyl-resveratrol were increased by PEF and ethephon treatments. The results show that PEF induced a defense response of plant cells and may have altered the cell/membrane's dielectric properties. PEF, an external stimulus or stress, is proposed as a promising new abiotic elicitor for stimulating secondary metabolites biosynthesis in plant cell cultures. [ABSTRACT FROM AUTHOR]

Cell cultures established from plants represent an attractive alternative to whole plants for effective production of bioactive secondary metabolites. Cell culture from Vitis vinifera L. cv. Gamay Fréaux accumulated high amounts of hydroxycinnamic acid derivatives and anthocyanins. Two new compounds were identified: 3- O-glucosylresveratrol, a stilbene derivative, abundant in cell suspension culture, and a hydroxyphenol, 4-(3,5-dihydroxyphenyl)-phenol, abundant in callus culture. The major anthocyanin monoglucosides present in cell suspension culture were cyanidin 3- O-glucoside and peonidin 3- O-glucoside, and the major cinnamoyl derivatives were cyanidin 3- O- p-coumaryl glucoside and peonidin 3- O- p-coumaryl glucoside. Three minor anthocyanin compounds were found in V. vinifera cell culture: delphinidin 3- O-glucoside, petunidin 3- O-glucoside, and delphinidin 3- O- p-coumaryl glucoside. Anthocyanin levels of cell suspension cultures increased significantly-about eight fold-after 4-day cultivation in new medium. Salicylic acid at a concentration of 50 μM did not enhance anthocyanin accumulation in cell suspension culture, and similar levels of jasmonic acid significantly reduced the anthocyanin content. [ABSTRACT FROM AUTHOR]

The chrysomelid beetle Phyllotreta striolata is an important pest of Brassicaceae in Southeast Asia and North America. Here, we identified the aggregation pheromone of a population of P. striolata from Taiwan, and host plant volatiles that interact with the pheromone. Volatiles emitted by feeding male P. striolata attracted males and females in the field. Headspace volatile analyses revealed that six sesquiterpenes were emitted specifically by feeding males. Only one of these, however, elicited an electrophysiological response from antennae of both sexes. A number of host plant volatiles, e.g., 1-hexanol, ( Z)-3-hexen-1-ol, and the glucosinolate hydrolysis products allyl isothiocyanate (AITC), 3-butenyl isothiocyanate, and 4-pentenyl isothiocyanate also elicited clear responses from the antenna. The active male-specific compound was identified as (+)-(6 R,7 S)-himachala-9,11-diene by chiral stationary phase gas-chromatography with coupled mass spectrometry, and by comparison with reference samples from Abies nordmanniana, which is known to produce the corresponding enantiomer. The pheromone compound was synthesized starting from (-)-α-himachalene isolated from Cedrus atlantica. Under field conditions, the activity of the synthetic pheromone required concomitant presence of the host plant volatile allyl isothiocyanate. However, both synthetic (+)-(6 R,7 S)-himachala-9,11-diene alone and in combination with AITC were attractive in a two-choice laboratory assay devoid of other natural olfactory stimuli. We hypothesize that P. striolata adults respond to the pheromone only if specific host volatiles are present. In the same laboratory set up, more beetles were attracted by feeding males than by the synthetic stimuli. Thus, further research will be necessary to reveal the components of a more complex blend of host or male-produced semiochemicals that might enhance trap attractiveness in the field. [ABSTRACT FROM AUTHOR]

Copyright of Herzschrittmachertherapie und Elektrophysiologie is the property of Springer Nature and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

We investigated the effects of two commercial diatomaceous earth based insecticides (DE), Protect-It® and SilicoSec®, the nano-structured silica product AL06, developed by the section for Urban Plant Ecophysiology at Humboldt University Berlin, and the monoterpenoids, eugenol, and cinnamaldehyde on two stored product pests, Callosobruchus maculatus and Sitophilus oryzae. Protect-It® was more effective than SilicoSec® against C. maculatus while the reverse was true for S. oryzae. Generally C. maculatus was more sensitive towards DE and silica treatment than S. oryzae. Mortality rate of both pest species increased when DE’s were applied to food commodities previously treated with a monoterpenoid. In admixture experiments, the toxicity of SilicoSec® + cinnamaldehyde (LD50 = 42.73 ppm), SilicoSec® + eugenol (LD50 = 24.30 ppm), and Protect-It® + eugenol (LD50 = 2.60 ppm) was increased over DE alone against S. oryzae. Both substances showed a synergistic effect considering their co-toxicity coefficient relative to the LD50-value. In contrast, we could not find any synergistic effects in experiments with C. maculatus. Here only Protect-It® + cinnamaldehyde (LD50 = 20.84 ppm) showed an additive effect while all other combinations of monoterpenoid and DE indicated antagonistic effects. In addition to contact insecticidal effects both monoterpenoids showed a strong fumigant action. The presented results indicate that the natural product DE has great potential to replace synthetic pesticides commonly used in stored product pest management. Efficacy of DE can be improved by adding certain monoterpenoids against certain insect pests. [ABSTRACT FROM AUTHOR]

Abstract  The effect of microstructure on the rheology of clay/polymer nanocomposites is investigated using dispersions of organically treated clay in nearly Newtonian poly(dimethylsiloxane). Degree of dispersion and floc size are altered by using two different dispersion procedures and by changing the shear history. The scaling for dynamic moduli of attractive colloids applies, except for a possible relaxation mechanism at very low frequencies. The time to reach the crossover at a given frequency is found to be extremely sensitive to the dispersion procedure used. Hydrodynamic and elastic components of the steady state stress, on the other hand, evolve in a very similar fashion for the different systems. Although the relaxation times of the elastic stress components change drastically with flow-induced changes in structure, the dispersion process hardly has an effect at all. Intermittent start-up flows in the forward and reverse directions show that anisotropy persists long after the flow has been arrested, even at shear rates where no large reversible flocs are present. The degree of dispersion only had a limited effect on the anisotropy. Finally, the effect of shear on structure recovery has been studied. Very low shear rates are found to increase the rate of recovery, even for small strains. [ABSTRACT FROM AUTHOR]

Copyright of Gesunde Pflanzen is the property of Springer Nature and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Atrial fibrillation (AF) and chronic heart failure (CHF) can be caused by each other, and therefore constitute a vicious circle. The prevalence of both conditions is about 1% in industrialized countries and increases with age. Although mortality is increased in heart failure, the additional prognostic relevance of AF in these patients is less clear. AF in patients with CHF can worsen heart failure symptoms, cause complications (eg, stroke), and is difficult to treat. Thus, prevention of AF entirely is an important goal. This review summarizes recent data concerning prognostic relevance, treatment, and means of primary and secondary prevention of AF in patients with CHF. [ABSTRACT FROM AUTHOR]

BACKGROUND AND OBJECTIVE: Atrial fibrillation (AF) is the most common cardiac arrhythmia. Recent studies suggest there is an angiotensin II-dependent increase in adhesion molecules and oxidative stress parameters during AF. These alterations appear to contribute to inflammatory and prothrombotic changes in the atrial endocardium (‘endocardial remodelling’), suggesting that patients with increased levels of these factors might be at risk of thromboembolic events. The purpose of the CREATIVE-AF (Impact of Irbesartan on Oxidative Stress and C-Reactive Protein Levels in Patients with Persistent Atrial Fibrillation) trial is to prove the principle concept that blockade of angiotensin II type 1 receptors by irbesartan reduces levels of circulating adhesion molecules and oxidative stress parameters in patients with persistent AF by 25% compared with placebo.ClinicalTrials.gov identifier: NCT00613496. METHODS: This is a prospective, randomized, double-blind, placebo-controlled, crossover study in patients with persistent/permanent AF. A total of 60 patients are planned to be included in the study. Patients will receive placebo and irbesartan therapy for 9 weeks each. Levels of adhesion molecules (intercellular adhesion molecule-1, vascular cell adhesion molecule-1), inflammatory markers (high sensitivity C-reactive protein, monocyte chemoattractant protein-1, von Willebrand factor, tumour growth factor-ß1, tumour necrosis factor-α, interleukin-6) and oxidative stress parameters (8-iso-prostaglandin F2α) will be determined after each treatment phase and compared with baseline levels.ClinicalTrials.gov identifier: NCT00613496. CONCLUSION: Angiotensin II type 1 receptor antagonists may help reduce levels of circulating adhesion molecules and oxidative stress parameters in patients with persistent AF. This article summarizes the rationale and design of the CREATIVE-AF trial, which has been designed to test this hypothesis.ClinicalTrials.gov identifier: NCT00613496. [ABSTRACT FROM AUTHOR]

Antifeeding and toxic effects of chemical extracts from Porteresia coarctata Takeoka on the insect pest Spodoptera litura (F.) were investigated in the laboratory. Hexane extracts of P. coarctata leaves were re-dissolved in dimethyl sulfoxide and applied in water to leaves of Ricinus communis L. (castor). A concentration of 1,000 and 2,000 ppm extract exhibited significant antifeeding and toxic effects to third instar larvae when compared to the same concentration of dimethyl sulfoxide in water as control. One day after feeding on extract-treated castor leaves, the mortality of S. litura larvae was 50%. Mortality increased to 95% after 11 days at a dosage of 2,000 ppm. Compared to the control, third instar larvae fed on castor leaves treated with P. coarctata leaf extract at different concentrations showed significant reduction in protein and DNA content in the fat body and midgut tissues. Results demonstrate the insecticidal and antifeedant properties of P. coarctata leaf extract against the generalist pest S. litura leading to biochemical changes in the insect body. Thus, P. coarctata contains phytochemicals, and the extract, in crude and pure form, has potential as a botanical insecticide in alternative control strategies against Lepidoptera pests. [ABSTRACT FROM AUTHOR]

Copyright of Medizinische Klinik (Urban & Vogel) is the property of Springer Nature and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Abstract Many constitutive equations have been proposed for thixotropic materials but the supporting experimental evidence has usually been rather fragmentary. To a large extent this is due to the difficulties involved in measuring thixotropic systems. These systems normally display various phenomena that result in poor accuracy and poor reproducibility of the measurements. Therefore, it has been attempted here to formulate a robust thixotropic system that allows accurate measurements and that would be suitable for detailed studies of thixotropy. The system that has been developed is based on a matrix liquid that consists of a high boiling paraffin oil and a low molecular weight poly(isobutylene). A suitable type of fumed silica is used as the dispersed phase. The various rheological parameters of the material can be altered by varying the concentration of the components and, if necessary, the molecular weight of the polymer. The relative humidity around the sample turns out to be an important factor in controlling the yield stress, and its effect is shown to be reversible. The selected system can be measured accurately over a wide range of measurement conditions. These include stress jump measurements, which can be used to separate viscous and elastic contributions. The highest possible shear rate is limited by the occurrence of a peculiar phenomenon that shows up in the normal stresses. [ABSTRACT FROM AUTHOR]

Stress relaxation in immiscible blends is studied for a well defined shear history, i.e. after prolonged steady state shearing. Model systems are used that consist of quasi-Newtonian liquid polymers. Hence the relaxation is dominated by changes in the morphology of the interface. Both shear stress and the first normal stress are considered. The measurements cover the entire concentration range. For dilute blends the interfacial contribution to the stress relaxation compares well with model predictions. Deviations occur when the matrix phase is slightly elastic. In that case the similarity between the relaxation of shear and normal stresses is also lost. The latter is attributed to a wider drop size distribution. Increasing the concentration of the disperse phase results in a complex evolution of the characteristic relaxation times. The normal stresses relax systematically slower than the shear stresses and the concentration curve includes two maxima. Even for equiviscous components the concentration curves are not symmetrical. It is concluded that even a slight degree of elasticity in the matrix phase drastically affects the morphology and the interfacial relaxation of such blends. [ABSTRACT FROM AUTHOR]