Environmental differences between sites control the diet and nutrition of the carnivorous plant Drosera rotundifolia

Background and aims: Carnivorous plants are sensitive to small changes in resource availability, but few previous studies have examined how differences in nutrient and prey availability affect investment in and the benefit of carnivory. We studied the impact of site-level differences in resource availability on ecophysiological traits of carnivory for Drosera rotundifolia L. Methods: We measured prey availability, investment in carnivory (leaf stickiness), prey capture and diet of plants growing in two bogs with differences in N deposition and plant available N: Cors Fochno (0.62 g m−2 yr.−1, 353 μg l−1), Whixall Moss (1.37 g m−2 yr.−1, 1505 μg l−1). The total N amount per plant and the contributions of prey/root N to the plants’ N budget were calculated using a single isotope natural abundance method. Results: Plants at Whixall Moss invested less in carnivory, were less likely to capture prey, and were less reliant on prey-derived N (25.5% compared with 49.4%). Actual prey capture did not differ between sites. Diet composition differed – Cors Fochno plants captured 62% greater proportions of Diptera. Conclusions: Our results show site-level differences in plant diet and nutrition consistent with differences in resource availability. Similarity in actual prey capture may be explained by differences in leaf stickiness and prey abundance

Direct Interaction between Two Viral Proteins, the Nonstructural Protein 2CATPase and the Capsid Protein VP3, Is Required for Enterovirus Morphogenesis

In spite of decades-long studies, the mechanism of morphogenesis of plus-stranded RNA viruses belonging to the genus Enterovirus of Picornaviridae, including poliovirus (PV), is not understood. Numerous attempts to identify an RNA encapsidation signal have failed. Genetic studies, however, have implicated a role of the non-structural protein 2CATPase in the formation of poliovirus particles. Here we report a novel mechanism in which protein-protein interaction is sufficient to explain the specificity in PV encapsidation. Making use of a novel “reporter virus”, we show that a quasi-infectious chimera consisting of the capsid precursor of C-cluster coxsackie virus 20 (C-CAV20) and the nonstructural proteins of the closely related PV translated and replicated its genome with wild type kinetics, whereas encapsidation was blocked. On blind passages, encapsidation of the chimera was rescued by a single mutation either in capsid protein VP3 of CAV20 or in 2CATPase of PV. Whereas each of the single-mutation variants expressed severe proliferation phenotypes, engineering both mutations into the chimera yielded a virus encapsidating with wild type kinetics. Biochemical analyses provided strong evidence for a direct interaction between 2CATPase and VP3 of PV and CAV20. Chimeras of other C-CAVs (CAV20/CAV21 or CAV18/CAV20) were blocked in encapsidation (no virus after blind passages) but could be rescued if the capsid and 2CATPase coding regions originated from the same virus. Our novel mechanism explains the specificity of encapsidation without apparent involvement of an RNA signal by considering that (i) genome replication is known to be stringently linked to translation, (ii) morphogenesis is known to be stringently linked to genome replication, (iii) newly synthesized 2CATPase is an essential component of the replication complex, and (iv) 2CATPase has specific affinity to capsid protein(s). These conditions lead to morphogenesis at the site where newly synthesized genomes emerge from the replication complex

Recent experimental probes of shear banding

Recent experimental techniques used to investigate shear banding are reviewed. After recalling the rheological signature of shear-banded flows, we summarize the various tools for measuring locally the microstructure and the velocity field under shear. Local velocity measurements using dynamic light scattering and ultrasound are emphasized. A few results are extracted from current works to illustrate open questions and directions for future research.Comment: Review paper, 23 pages, 11 figures, 204 reference

Lack of trade-offs between the male and female sexual functions in the gynodioecious herb Geranium sylvaticum

Resource allocation trade-offs between sexual functions are predicted, but these are usually measured only at the whole plant level. In some gynodioecious species, individuals with partially restored male fertility exist providing an opportunity to investigate whether the costs associated with male fertility restoration are linked to seed production. In this study, we examined whether there is a relationship between the numbers of stamens and seeds produced both at the flower level and at the plant level in the gynodioecious herb Geranium sylvaticum. We individually marked flowers in plants varying in the degree of male sterility in the field and counted the number of seeds produced. There was no significant correlation between the numbers of stamens and seeds produced at the flower level suggesting an absence of resource trade-off between female and male functions. Furthermore, the numbers of stamens and seeds were positively correlated at the plant level. The lack of trade-offs between the two sexual functions in this species indicates that relative sex allocation was not affected by resources within a single season and/or that the male costs were relatively small

Overzicht van klachten en diagnoses van patienten van de Witrussisch-Nederlandse polikliniek te Gomel (Oktober 1991 - September 1993)

Het rapport geeft een overzicht van de medische consumptie van 4500 personen welke gezien werden op de Witrussische-Nederlandse polikliniek te Gomel in Wit-Rusland van oktober 1991 tot september 1993. Dit Witrussisch-Nederlands samenwerkingsverband werd opgezet in het kader van een Nederlands Humanitair Hulpproject ten gevolge van het reactorongeval te Tsjernobyl in 1986. In een nieuw computersysteem voor patientenregistratie werden personalia, klachtenpatroon, diagnose, behandelingsstrategie en voorgeschreven therapie of medicatie geregistreerd. Met name werd gekeken naar klachten welke verband houden met blootstelling aan ioniserende straling. De populatie bestond voor 75% uit liquidatoren, mensen met een (beroepsmatige) mogelijk verhoogde blootstelling. Cardiovasculaire, gastro-intestinale of neurologische klachten, en klachten van het bewegingsapparaat waren het meest frequent, evenals het aantal diagnoses in deze subgroepen. Het patroon van klachten en diagnoses was vergelijkbaar met dat van een Nederlandse polikliniek interne geneeskunde, verhoogd waren struma, gastritis, maag- en dunnedarmzweren. Diagnoses welke gerelateerd kunnen zijn aan blootstelling aan ioniserende straling werden geanalyseerd. Een maligniteit werd 23x vastgesteld. Een groot aantal schildklieraandoeningen werd gediagnostiseerd. In 54 gevallen werd een haematologische ziekte vastgesteld, waarvan 5 maligniteiten. Cataract werd in 19 gevallen gediagnostiseerd. In alle gevallen liggen de getallen lager dan in een Nederlandse populatie van dezelfde grootte. Bij de behandelingsplannen werd het hoge aantal voorschrijvingen van homeopathische middelen (50%) geweten aan schaarste en onbekendheid met voorschrijven van westerse geneesmiddelen.This report provides a survey of the medical consumption of 4500 patients seen at the Belarussian-Dutch Outpatient Clinic in Gomel, Belarus during 1991-1993. This clinic was established in the framework of Dutch humanitarian aid following the Chernobyl reactor accident in 1986. A computerized patient registration programme was introduced. Special attention was paid to complaints that could be related to possible enhanced radiation exposure of the patients. The patient population consisted approximately 75% of liquidators, persons who may have been exposed to higher doses of radiation than the general public. Complaints affecting cardiovascular, gastro-intestinal, neurological and locomotor systems were uttered most frequently, consequently most diagnoses were related to these disciplines. The quantity of types of complaints and diagnoses were in agreement with each other, except for thyroid disease. The pattern of complaints and diagnoses was roughly comparable to the situation in a general outpatient clinic internal medicine in the Netherlands and the number of goitre, gastritis, gastric and duodenal ulcers was higher. Diagnoses that could be attributed to increased radiation exposure were analyzed. A large number of cases of thyroid disease were diagnosed. Haematologic disease was registered in 54 cases, five of these concerned malignant disease. Cataract was diagnosed in 19 cases, both lower than in a Dutch population of similar size. The same accounted for malignant disease (23x). Treatment plans consisted of different therapies and medication. The high percentage of prescriptions of homeopathic remedies (50%) may be due to scarcity of and unfamiliarity with prescribing western medication.VW

About the role of visual field defects in pure alexia

Pure alexia is an acquired reading disorder characterized by a disproportionate prolongation of reading time as a function of word length. Although the vast majority of cases reported in the literature show a right-sided visual defect, little is known about the contribution of this low-level visual impairment to their reading difficulties. The present study was aimed at investigating this issue by comparing eye movement patterns during text reading in six patients with pure alexia with those of six patients with hemianopic dyslexia showing similar right-sided visual field defects. We found that the role of the field defect in the reading difficulties of pure alexics was highly deficit-specific. While the amplitude of rightward saccades during text reading seems largely determined by the restricted visual field, other visuo-motor impairments-particularly the pronounced increases in fixation frequency and viewing time as a function of word length-may have little to do with their visual field defect. In addition, subtracting the lesions of the hemianopic dyslexics from those found in pure alexics revealed the largest group differences in posterior parts of the left fusiform gyrus, occipito-temporal sulcus and inferior temporal gyrus. These regions included the coordinate assigned to the centre of the visual word form area in healthy adults, which provides further evidence for a relation between pure alexia and a damaged visual word form area. Finally, we propose a list of three criteria that may improve the differential diagnosis of pure alexia and allow appropriate therapy recommendations