Lack of evidence for western flower thrips biotypes base don intra and inter-strain variation in gut bacteria

Western flower thrips is a polyphagous insect, which during the last 30 years has become a world wide pest. It was found earlier that these thrips are associated with a type of Erwinia species gut bacteria. In this study we examine the variation of bacteria within and between thrips individuals and try to find evidence for biotypes in western flower thrips regarding the type of gut bacteria. The existence of biotypes in this thrips species has been suggested by different authors. For example, thrips populations have been found that differ in resistance against pesticides and in their ability to transmit plant viruses. With biotypes we mean groups of individuals (strains, populations, lines) of a species which differ in one or more traits with other groups of that species. The gut bacteria of thrips are acquired by young thrips larvae via the host plant and have a beneficial effect on thrips development and oviposition. We studied thrips strains from different countries and host plants, and the isofemale lines that were created from them, on bean plant leaves. All thrips lines that we studied contained Erwinia species gut bacteria. Morphological and biochemical characteristics of gut bacteria from the thrips isofemale lines were similar to the Erwinia type strain from the reference, a thrips strain cultured on chrysanthemum in Amsterdam (TAC 93.XII.8). Per isofemale line we studied five thrips individuals and per thrips we studied four bacterial colonies, with RAPD markers. The genetic variation between bacteria isolated from thrips was as large among isofemale lines as within isofemale lines. No evidence for thrips biotypes was found. Bacteria within one thrips individual show a stronger degree of similarity than bacteria from different thrips individuals within a single rearing. This is probably due to a bottleneck caused by the limited number of successful infections of bacteria into the gut of the thrip

Public interests in the implementation of the EU ETS in the Netherlands: stakeholder perspectives - 61

Political Science; IC

Glutathione S-transferase activity and isoenzyme composition in benign ovarian tumours, untreated malignant ovarian tumours, and malignant ovarian tumours after platinum/cyclophosphamide chemotherapy.

Glutathione S-transferase (GST) isoenzyme composition, isoenzyme quantities and enzymatic activity were investigated in benign (n = 4) ovarian tumours and malignant ovarian tumours, before (n = 20) and after (n = 16) chemotherapy. Enzymatic activity of GST in cytosols was measured by determining 1-chloro-2,4-dinitrobenzene conjugation with glutathione, cytosolic GST subunits were determined by wide pore reversed phase HPLC, using a S-hexylglutathione-agarose affinity column, and isoelectric focussing. Both GST activity and GST pi amount were not related to histopathologic type, differentiation grade, or tumour volume index in untreated malignant tumours. GST isoenzyme patterns were identical in benign tumours and malignant tumours before and after platinum/cyclophosphamide chemotherapy, while GST pi was the predominant transferase. Mean GST activity and GST pi amount were decreased (P < 0.05) in malignant ovarian tumours after platinum/cyclophosphamide chemotherapy compared to untreated ovarian malignant tumours. No relation was found in untreated ovarian tumours between GST pi amount and response to platinum/cyclophosphamide chemotherapy. Thus, within the limitations of the current study no arguments were found for a role of GST in in vivo drug resistance of malignant ovarian tumours to platinum/cyclophosphamide chemotherapy

Egg-mediated maternal effects in a cooperatively breeding cichlid fish.

Mothers can influence offspring phenotype through egg-mediated maternal effects, which can be influenced by cues mothers obtain from their environment during offspring production. Developing embryos use these components but have mechanisms to alter maternal signals. Here we aimed to understand the role of mothers and embryos in how maternal effects might shape offspring social phenotype. In the cooperatively breeding fish Neolamprologus pulcher different social phenotypes develop in large and small social groups differing in predation risk and social complexity. We manipulated the maternal social environment of N. pulcher females during egg laying by allocating them either to a small or a large social group. We compared egg mass and clutch size and the concentration of corticosteroid metabolites between social environments, and between fertilized and unfertilized eggs to investigate how embryos deal with maternal signalling. Mothers in small groups produced larger clutches but neither laid smaller eggs nor bestowed eggs differently with corticosteroids. Fertilized eggs scored lower on a principal component representing three corticosteroid metabolites, namely 11-deoxycortisol, cortisone, and 11-deoxycorticosterone. We did not detect egg-mediated maternal effects induced by the maternal social environment. We discuss that divergent social phenotypes induced by different group sizes may be triggered by own offspring experience

Triggering synchronized oscillations through arbitrarily weak diversity in close-to-threshold excitable media

It is shown that arbitrarily weak (frozen) heterogeneity can induce global synchronized oscillations in excitable media close to threshold. The work is carried out on networks of coupled van der Pol-FitzHugh-Nagumo oscillators. The result is shown to be robust against the presence of internal dynamical noise.Comment: 4 pages (RevTeX 3 style), 5 EPS figures, submitted to Phys. Rev. E (16 aug 2001

Mass spectrometric quantification of urinary 6-sulfatoxymelatonin:age-dependent excretion and biological variation

Objectives: Regulators of circadian rhythm, including melatonin, influence fundamental biological processes. Measuring the melatonin metabolite 6-sulfatoxymelatonin in urine can estimate melatonin production. 6-sulfatoxymelatonin is mainly analyzed by immunoassays, but these methods are hampered by cross-reactivity and poor reproducibility when used to analyze small molecules. Therefore, we validated a high-throughput liquid chromatography with tandem mass spectrometry (LC-MS/MS) method to quantify 6-sulfatoxymelatonin in urine. We evaluated age-dependent 24-h excretion of 6-sulfatoxymelatonin into urine and the biological variation of urinary excretion in healthy individuals. Methods: The online solid phase extraction method combined with LC-MS/MS was validated according to international guidelines, and used to measure the excretion of 6-sulfatoxymelatonin into urine of 240 healthy individuals. Biological variation of 6-sulfatoxymelatonin excretion was examined in 10 healthy individuals. Results: Urinary 6-sulfatoxymelatonin results were well within the validation criteria (interassay coefficient of variation: Conclusions: This MS-based method enables straightforward, reproducible, and sensitive quantification of 6-sulfatoxymelatonin in urine. Urinary 6-sulfatoxymelatonin levels decreased with age. Biological variation of 6-sulfatoxymelatonin excretion into urine was high between subjects and lower within subjects, indicating that repeated measurements of 6-sulfatoxymelatonin in 24-h urine are needed in future studies

Estimating the spatial position of marine mammals based on digital camera recordings

Estimating the spatial position of organisms is essential to quantify interactions between the organism and the characteristics of its surroundings, for example,predator–prey interactions, habitat selection, and social associations. Because marine mammals spend most of their time under water and may appear at the surface only briefly, determining their exact geographic location can be challenging.Here, we developed a photogrammetric method to accurately estimatethe spatial position of marine mammals or birds at the sea surface. Digital recordings containing landscape features with known geographic coordinates can be used to estimate the distance and bearing of each sighting relative to the observation point. The method can correct for frame rotation, estimates pixel size based on the reference points, and can be applied to scenarios with and without a visible horizon. A set of R functions was written to process the images and obtain accurate geographic coordinates for each sighting. The method is applied to estimate the spatiotemporal fine-scale distribution of harbourporpoises in a tidal inlet. Video recordings of harbour porpoises were made from land, using a standard digital single-lens reflex (DSLR) camera, positioned at a height of 9.59 m above mean sea level. Porpoises were detected up to a distance of ~3136 m (mean 596 m), with a mean location error of 12 m. The method presented here allows for multiple detections of different individuals within a single video frame and for tracking movements of individuals based on repeated sightings. In comparison with traditional methods, this method only requires a digital camera to provide accurate location estimates. It especially has great potential in regions with ample data on local (a)biotic conditions, to help resolve functional mechanisms underlying habitat selection and other behaviors in marine mammals in coastal areas

Review: Quality of Life in Lower Limb Peripheral Vascular Surgery

PURPOSE: Vascular intervention studies generally consider patency and limb salvage as primary outcomes. However, quality of life is increasingly considered an important patient-oriented outcome measurement of vascular interventions. Existing literature was analyzed to determine the effect of different treatments on quality of life for patients suffering from either claudication or critical limb ischemia. BASIC METHODS: A review of the literature was undertaken in the Medline library. A search was performed on quality of life in peripheral arterial disease. Results were stratified according to treatment groups. PRINCIPAL FINDINGS: Twenty-one articles described quality of life in approximately 4600 patients suffering from peripheral arterial disease. Invasive treatment generally results in better quality of life scores (at a maximum of 2 years of follow-up), compared with non-invasive treatment. In patients with critical limb ischemia, successful revascularization improves quality of life scores. Only one study reported long-term results. CONCLUSIONS: Increase in quality of life scores can be found for any intervention performed for peripheral arterial disease. However, there is scarce information on long-term quality of life after vascular intervention.info:eu-repo/semantics/publishedVersio

De ex-gedetineerde: ons een zorg : mini-symposium

Bijdragen minisymposium namens Stichting tot bevordering van het wetenschappelijk onderzoek en onderwijs m.b.t. het justitiepastoraat, gehouden op 2 juni 2015 te Amsterdam