Innovatienetwerk hyacint zoekt oplossingen voor bolbeschadiging

Beschadigingen aan hyacenten die ontstaan tijdens de oogst en verwerking kunnen de teler veel geld kosten en uiteindelijk ook het imago van de hyacint negatief beïnvloeden. Een innovatienetwerkgroep van vijf telers werkte samen met diverse partijen om ne te gaan wat er aan beschadiging is te doe

Verzamelen van gegevens over de aanwezigheid van (dwerg)cicaden in en rond een aantal percelen met hyacinten in de Zuidelijke Bollenstreek : Voortgezet diagnostisch onderzoek 2009

In het broeiseizoen 2007, 2008 en 2009 zijn bij Diagnostiekservice van PPO geregeld monsters hyacint gebracht voor diagnostisch onderzoek waarbij sprake bleek van een besmetting met fytoplasma’s. Deze ziekteverwekker wordt overgebracht door dwergcicaden waarvan tot nu toe wordt aangenomen dat ze in Nederland niet goed kunnen overwinteren. Omdat al drie jaar op rij sprake was van partijen hyacinten waarin vaker fytoplasma’s werden aangetoond was de vraag of dit te maken zou kunnen hebben met de mildere winters van de afgelopen jaren. Daardoor zouden er mogelijk betere overlevingskansen zijn voor dwergcicaden waardoor ze ook al vroeg in het voorjaar in Nederland actief voor verspreiding van fytoplasma’s zouden kunnen zorgen. Uit oud onderzoek is wel bekend dat destijds cicaden pas eind mei in Nederland werden aangetroffen. Voor de afgelopen jaren is daarover niets bekend en zou middels het monitoren van dwergcicaden daarover meer informatie kunnen worden verkregen. Het bleek dat vanaf eind april/begin mei al (dwerg)cicaden konden worden gevangen op een aantal percelen. Met name op percelen in de buurt van bosschages werden grotere aantallen cicaden gevangen. Ook zijn in mei tot juli 2009 nog lijmplaten uitgezet in een tweetal percelen in Noord Holland om de aanwezigheid van (dwerg)cicaden daar ook duidelijk te krijgen. Het bleek dat in Noord Holland geen (dwerg)cicaden waren te vangen, waarmee het dus ook duidelijk wordt waarom in hyacinten die in Noord Holland worden geteeld relatief weinig problemen met een fytoplasma-besmetting worden vastgesteld. Uit het monitoren van (dwerg)cicaden in de Zuidelijke Bollenstreek blijkt dus dat al veel vroeger in het groeiseizoen dan in het verleden is vastgesteld volop (dwerg)cicaden konden worden gevangen. Dit betekent ook dat deze insecten eerder en dus langer dan werd gedacht in een perceel hyacinten fytoplasma’s kunnen overbrengen. Het is dan ook wenselijk dat bollentelers van hyacinten daar hun strategie m.b.t. de bestrijding van (dwerg)cicaden op aanpassen door eerder een bespuiting met een insecticide uit te voeren dan gewoonlijk wordt gedaan. Het feit dat cicaden op percelen hyacinten in Zuid Holland al in april zijn gevangen roept diverse andere vragen op waar nader onderzoek voor wenselijk is

Fingerprinting of hydroxyl radical-attacked polysaccharides by N-isopropyl-2-aminoacridone labelling

Hydroxyl radicals ((•)OH) cause non-enzymic scission of polysaccharides in diverse biological systems. Such reactions can be detrimental (e.g. causing rheumatic and arthritic diseases in mammals) or beneficial (e.g. promoting the softening of ripening fruit, and biomass saccharification). Here we present a method for documenting (•)OH action, based on fluorescent labelling of the oxo groups that are introduced as glycosulose residues when (•)OH attacks polysaccharides. The method was tested on several polysaccharides, especially pectin, after treatment with Fenton reagents. 2-Aminoacridone plus cyanoborohydride reductively aminated the oxo groups in treated polysaccharides; the product was then reacted with acetone plus cyanoborohydride, forming a stable tertiary amine with the carbohydrate linked to N-isopropyl-2-aminoacridone (pAMAC). Digestion of labelled pectin with ‘Driselase’ yielded several fluorescent products which on electrophoresis and HPLC provided a useful ‘fingerprint’ indicating (•)OH attack. The most diagnostic product was a disaccharide conjugate of the type pAMAC·UA-GalA (UA=unspecified uronic acid), whose UA-GalA bond was Driselase-resistant (product 2A). 2A was clearly distinguishable from GalA-GalA–pAMAC (disaccharide labelled at its reducing end), which was digestible to GalA–pAMAC. The methodology is applicable, with appropriate enzymes in place of Driselase, for detecting natural and artificial (•)OH attack in diverse plant, animal and microbial polysaccharides

Characterisation of the Physical Composition and Microbial Community Structure of Biofilms within a Model Full-Scale Drinking Water Distribution System

Within drinking water distribution systems (DWDS), microorganisms form multi-species biofilms on internal pipe surfaces. A matrix of extracellular polymeric substances (EPS) is produced by the attached community and provides structure and stability for the biofilm. If the EPS adhesive strength deteriorates or is overcome by external shear forces, biofilm ismobilised into the water potentially leading to degradation of water quality. However, little is known about the EPS within DWDS biofilms or how this is influenced by community composition or environmental parameters, because of the complications in obtaining biofilm samples and the difficulties in analysing EPS. Additionally, although biofilms may contain various microbial groups, research commonly focuses solely upon bacteria. This research applies an EPS analysis method based upon fluorescent confocal laser scanning microscopy (CLSM) in combination with digital image analysis (DIA), to concurrently characterize cells and EPS (carbohydrates and proteins) within drinking water biofilms from a full-scale DWDS experimental pipe loop facility with representative hydraulic conditions. Application of the EPS analysismethod, alongside DNA fingerprinting of bacterial, archaeal and fungal communities, was demonstrated for biofilms sampled from different positions around the pipeline, after 28 days growth within the DWDS experimental facility. The volume of EPS was 4.9 times greater than that of the cells within biofilms, with carbohydrates present as the dominant component. Additionally, the greatest proportion of EPS was located above that of the cells. Fungi and archaea were established as important components of the biofilm community, although bacteria were more diverse.Moreover, biofilms from different positions were similar with respect to community structure and the quantity, composition and three-dimensional distribution of cells and EPS, indicating that active colonisation of the pipe wall is an important driver inmaterial accumulation within the DWDS

Environmental Enrichment Preceding Early Adulthood Methylphenidate Treatment Leads to Long Term Increase of Corticosterone and Testosterone in the Rat

Attention-deficit/hyperactivity disorder (ADD/ADHD) has been emerging as a world-wide psychiatric disorder. There appears to be an increasing rate of stimulant drug abuse, specifically methylphenidate (MPH) which is the most common treatment for ADHD, among individuals who do not meet the criteria for ADHD and particularly for cognitive enhancement among university students. However, the long term effects of exposure to MPH are unknown. Thus, in light of a developmental approach in humans, we aimed to test the effects of adolescence exposure to enriched environment (EE) followed by MPH administration during early adulthood, on reactions to stress in adulthood. Specifically, at approximate adolescence [post natal days (PND) 30–60] rats were reared in EE and were treated with MPH during early adulthood (PND 60–90). Adult (PND 90–92) rats were exposed to mild stress and starting at PND 110, the behavioral and endocrine effects of the combined drug and environmental conditions were assessed. Following adolescence EE, long term exposure to MPH led to decreased locomotor activity and increased sucrose preference. EE had a beneficial effect on PPI (attentive abilities), which was impaired by long term exposure to MPH. Finally, the interaction between EE and, exposure to MPH led to long-term elevated corticosterone and testosterone levels. In view of the marked increase in MPH consumption over the past decade, vigilance is crucial in order to prevent potential drug abuse and its long term detrimental consequences

Association of depressive disorders, depression characteristics and antidepressant medication with inflammation

Growing evidence suggests that immune dysregulation may be involved in depressive disorders, but the exact nature of this association is still unknown and may be restricted to specific subgroups. This study examines the association between depressive disorders, depression characteristics and antidepressant medication with inflammation in a large cohort of controls and depressed persons, taking possible sex differences and important confounding factors into account. Persons (18–65 years) with a current (N=1132) or remitted (N=789) depressive disorder according to DSM-IV criteria and healthy controls (N=494) were selected from the Netherlands Study of Depression and Anxiety. Assessments included clinical characteristics (severity, duration and age of onset), use of antidepressant medication and inflammatory markers (C-reactive protein (CRP), interleukin-6 (IL-6), tumor necrosis factor-alpha (TNF-α)). After adjustment for sociodemographics, currently depressed men, but not women, had higher levels of CRP (1.33 versus 0.92 mg l−1, P<0.001, Cohen's d=0.32) and IL-6 (0.88 versus 0.72 pg ml−1, P=0.01, Cohen's d=0.23) than non-depressed peers. Associations reduced after considering lifestyle and disease indicators — especially body mass index — but remained significant for CRP. After full adjustment, highest inflammation levels were found in depressed men with an older age of depression onset (CRP, TNF-α). Furthermore, inflammation was increased in men using serotonin–norepinephrine reuptake inhibitors (CRP, IL-6) and in men and women using tri- or tetracyclic antidepressants (CRP), but decreased among men using selective serotonin reuptake inhibitors (IL-6). In conclusion, elevated inflammation was confirmed in depressed men, especially those with a late-onset depression. Specific antidepressants may differ in their effects on inflammation