Studying genetics of adaptive variation in model organisms: flowering time variation in Arabidopsis lyrata

Arabidopsis thaliana has emerged as a model organism for plant developmental genetics, but it is also now being widely used for population genetic studies. Outcrossing relatives of A. thaliana are likely to provide suitable additional or alternative species for studies of evolutionary and population genetics. We have examined patterns of adaptive flowering time variation in the outcrossing, perennial A. lyrata. In addition, we examine the distribution of variation at marker genes in populations form North America and Europe. The probability of flowering in this species differs between southern and northern populations. Northern populations are much less likely to flower in short than in long days. A significant daylength by region interaction shows that the northern and southern populations respond differently to the daylength. The timing of flowering also differs between populations, and is made shorter by long days, and in some populations, by vernalization. North American and European populations show consistent genetic differentiation over microsatellite and isozyme loci and alcohol dehydrogenase sequences. Thus, the patterns of variation are quite different from those in A. thaliana, where flowering time differences show little relationship to latitude of origin and the genealogical trees of accessions vary depending on the genomic region studied. The genetic architecture of adaptation can be compared in these species with different life histories.     

Males Benefit from Mating with Outbred Females in Drosophila littoralis: Male Choice for Female Genetic Quality?

The evolution and expression of mate choice behaviour in either sex depends on the sex‐specific combination of mating costs, benefits of choice and constraints on choice. If the benefits of choice are larger for one sex, we would expect that sex to be choosier, assuming that the mating costs and constraints on choice are equal between sexes. Because deliberate inbreeding is a powerful genetic method for experimental manipulation of the quality of study organisms, we tested the effects of both male and female inbreeding on egg and offspring production in Drosophila littoralis. Female inbreeding significantly reduced offspring production (mostly due to lower egg‐to‐adult viability), whereas male inbreeding did not affect offspring production (despite a slight effect of paternal inbreeding on egg‐to‐adult viability). As inbreeding depressed female quality more than male quality, the benefits of mate choice were larger for males than for females. In mate choice experiments, inbreeding did not affect male mating success (measured as a probability to be accepted as a mate in a large group), suggesting that females did not discriminate among inbred and outbred males. In contrast, female mating success was affected by inbreeding, with outbred females having higher mating success than inbred females. This result was not explained by lower activity of inbred females. Our results show that D. littoralis males benefit from mating with outbred females of high genetic quality and suggest adaptive male mate choice for female genetic quality in this species. Thus, patterns of mating success in mate choice trials mirrored the benefits of choice: the sex that benefited more from choice (i.e. males) was more choosy.     

CD marker expression profiles of human embryonic stem cells and their neural derivatives,determined using flow-cytometric analysis,reveal a novel CD marker for exclusion of pluripotent stem cells

Human embryonic stem cells (hESCs) are pluripotent cells that can differentiate into neural cell lineages. These neural populations are usually heterogeneous and can contain undifferentiated pluripotent cells that are capable of producing teratomas in cell grafts. The characterization of surface protein profiles of hESCs and their neural derivatives is important to determine the specific markers that can be used to exclude undifferentiated cells from neural populations. In this study, we analyzed the cluster of differentiation (CD) marker expression profiles of seven undifferentiated hESC lines using flow-cytometric analysis and compared their profiles to those of neural derivatives. Stem cell and progenitor marker CD133 and epithelial adhesion molecule marker CD326 were more highly expressed in undifferentiated hESCs, whereas neural marker CD56 (NCAM) and neural precursor marker (chemokine receptor) CD184 were more highly expressed in hESC-derived neural cells. CD326 expression levels were consistently higher in all nondifferentiated hESC lines than in neural cell derivatives. In addition, CD326-positive hESCs produced teratomas in SCID mouse testes, whereas CD362-negative neural populations did not. Thus, CD326 may be useful as a novel marker of undifferentiated hESCs to exclude undifferentiated hESCs from differentiated neural cell populations prior to transplantation.     

How does biodiversity conservation argumentation generate effects in policy cycles?

Arguments in the formulation, implementation and evaluation of biodiversity policy frame conservation in a range of ways and express interests that can be conflicting. Policy processes are cyclic and iterative by nature and as policies are constantly reformulated, argumentation has an important role at each policy stage. In this paper, we utilise the policy cycle model to shed light on biodiversity-related policy processes and the ways in which argumentation generates effects at different stages of these processes. The paper first draws on literature and the theory-driven assumptions are then illustrated with insights from four European case studies on different policy processes in which biodiversity conservation plays a role. The analysis shows that argumentation tends to evolve over the course of the policy cycle, and framing has a key role across the different policy stages. It is concluded that the ways in which arguments persist, accumulate, diffuse, and replace old arguments, should be the target of increased attention in policy analysis.     

A validated method for the detection and quantitation of 50 drugs of abuse and medicinal drugs in oral fluid by gas chromatography-mass spectrometry

Oral fluid is of increasing interest as an alternative sample matrix in drugs of abuse analysis. Compared to the conventional sample matrix blood, sample volumes of oral fluid are smaller and the concentrations of some drugs can be much lower. This imposes some restrictions on the analysis method, which has to be able to detect and quantify multiple analytes from a small sample volume at low concentrations. A sensitive multi-component method for quantitative determination of 50 drug compounds from oral fluid samples collected with the StatSure SalivaSampler? device was developed. The compounds analysed include cannabis, cocaine, amphetamines, opioids, benzodiazepines and other psychoactive medicines. Both liquid–liquid-extraction (LLE) and solid-phase-extraction (SPE) are employed in the sample pre-treatment and the samples are analysed using gas chromatography–mass spectrometry (GC–MS) with the mass selective detector (MSD) operating in either electron ionization (EI) or negative-ion chemical ionization (NICI) mode. The method was fully validated, and the validated parameters included linearity, selectivity, accuracy, precision, and extraction efficiency. Stability of the collected samples during storage at ?18 °C was also studied, and even after over a year's storage all analyte concentrations were more than 60% of the original concentrations. The described method is suitable for routine analysis of oral fluid samples and it has been applied to analysis of more than 4000 oral fluid samples collected anonymously from volunteer road users in Finland during 2007–2009 as a part of the EU project DRUID (Driving under the Influence of Drugs, Alcohol and Medicines). At the moment the developed method is the most comprehensive validated analysis method for oral fluid samples.     

Revealing the True Incidence of Pandemic A(H1N1)pdm09 Influenza in Finland during the First Two Seasons — An Analysis Based on a Dynamic Transmission Model

The threat of the new pandemic influenza A(H1N1)pdm09 imposed a heavy burden on the public health system in Finland in 2009-2010. An extensive vaccination campaign was set up in the middle of the first pandemic season. However, the true number of infected individuals remains uncertain as the surveillance missed a large portion of mild infections. We constructed a transmission model to simulate the spread of influenza in the Finnish population. We used the model to analyse the two first years (2009-2011) of A(H1N1)pdm09 in Finland. Using data from the national surveillance of influenza and data on close person-to-person (social) contacts in the population, we estimated that 6% (90% credible interval 5.1 – 6.7%) of the population was infected with A(H1N1)pdm09 in the first pandemic season (2009/2010) and an additional 3% (2.5 – 3.5%) in the second season (2010/2011). Vaccination had a substantial impact in mitigating the second season. The dynamic approach allowed us to discover how the proportion of detected cases changed over the course of the epidemic. The role of time-varying reproduction number, capturing the effects of weather and changes in behaviour, was important in shaping the epidemic.     

Systemic Induction of Salicylates in Salix myrsinifolia(Salisb.)

We studied the induction of salicylates in mature leaves ofSalix myrsinifolia Salisb. (Salicaceae) following severe woundingby a specialist leaf-beetle Phratora vitellinae L. (Chrysomelidae).Levels of individual salicylates and aromatic amino acids andtheir total levels were determined in leaves at different developmentalstages. Induction of salicylates depended on: (1) the individualcompound; (2) the developmental stage of the plant organ; and(3) the genotype of the plant. Induction of salicylates wassystemic: levels of salicylates rose in unwounded young immatureand mature leaves, but no local response was detected in woundedleaves. In addition, there were clear clonal variations in boththe constant and induced levels of salicylates: clones withthe highest levels of salicylates were also most capable ofincreasing this level in response to herbivore attack i.e. notrade-off between constant and induced levels was detected.Furthermore, the levels of three aromatic amino acids, Phe,Tyr and Trp, increased in immature leaves of herbivore-affectedplants, which may indicate induction of enzymes of the shikimatepathway by wounding. The increase in salicylates was suggestedto be a consequence of an increased rate of synthesis ratherthan that of translocation. The induced levels of salicylatesdid not affect the subsequent feeding of highly specializedP. vitellinae. However, the ability to increase levels of salicylatesmay reduce grazing by generalist herbivores which are not ableto tolerate high levels of salicylates. Copyright 2001 Annalsof Botany Company Salix myrsinifolia, dark-leaved willow, Phratora vitellinae, salicylates, phenolic glycosides, herbivory, induced defence     

Dynamic association of human insulin receptor with lipid rafts in cells lacking caveolae

Cholesterol-sphingolipid rich plasma membrane domains, known as rafts, have emerged as important regulators of signal transduction. The adipocyte insulin receptor (IR) is localized to and signals via caveolae that are formed by polymerization of caveolins. Caveolin binds to IR and stimulates signalling. We report that, in liver-derived cells lacking caveolae, autophosphorylation of the endogenous IR is dependent on raft lipids, being compromised by acute cyclodextrin-mediated cholesterol depletion or by antibody clustering of glycosphingolipids. Moreover, we provide evidence that IR becomes recruited to detergent-resistant domains upon ligand binding and that clustering of GM2 ganglioside inhibits IR signalling apparently by excluding the ligand-bound IR from these domains. Our results indicate that, in cells derived from liver, an important insulin target tissue, caveolae are not required for insulin signalling. Rather, the dynamic recruitment of the ligand-bound IR into rafts may serve to regulate interactions in the initiation of the IR signalling cascade.     

Regulation of angiotensin-converting enzyme production by nicotine in human endothelial cells

Nicotine, a component of cigarette smoke, has been implicated in the pathogenesis of cardiovascular disease. We examined whether nicotine regulates angiotensin-converting enzyme (ACE), an enzyme that plays an important role in the pathophysiology of atherosclerosis and hypertension. Human umbilical cord vein endothelial cells were treated with nicotine (0.1-1 microM) alone or in combination with vascular endothelial growth factor (VEGF; 0.5 nM) or GF-109203X (GFX; 2.5 microM). The amount of ACE in intact endothelial cells was measured by an inhibitor-binding assay method, and ACE mRNA levels were quantified using LightCycler technology. Phosphorylated PKC levels were measured by Western immunoblotting. Nicotine did not modulate basal ACE production but significantly potentiated VEGF-induced ACE upregulation. Treatment of endothelial cells with the PKC inhibitor GFX totally blocked VEGF- and nicotine-induced ACE upregulation. VEGF induced PKC phosphorylation, which was potentiated by cotreatment with nicotine. We conclude that nicotine significantly potentiated VEGF-induced ACE upregulation. This effect was probably mediated by PKC phosphorylation. The interaction of nicotine with VEGF in ACE induction may contribute to the pathogenesis of smoking-related cardiovascular disease.