INTEGRATING LANDSCAPE GENOMICS AND SPATIALLY EXPLICIT APPROACHES TO DETECT LOCI UNDER SELECTION IN CLINAL POPULATIONS

Uncovering the genetic basis of adaptation hinges on the ability to detect loci under selection. However, population genomics outlier approaches to detect selected loci may be inappropriate for clinal populations or those with unclear population structure because they require that individuals be clustered into populations. An alternate approach, landscape genomics, uses individual‐based approaches to detect loci under selection and reveal potential environmental drivers of selection. We tested four landscape genomics methods on a simulated clinal population to determine their effectiveness at identifying a locus under varying selection strengths along an environmental gradient. We found all methods produced very low type I error rates across all selection strengths, but elevated type II error rates under “weak” selection. We then applied these methods to an AFLP genome scan of an alpine plant, Campanula barbata, and identified five highly supported candidate loci associated with precipitation variables. These loci also showed spatial autocorrelation and cline patterns indicative of selection along a precipitation gradient. Our results suggest that landscape genomics in combination with other spatial analyses provides a powerful approach for identifying loci potentially under selection and explaining spatially complex interactions between species and their environment.     

Stent implantation in acute myocardial infarction using a heparin-coated stent: a pilot study as a preamble to a randomized trial comparing balloon angioplasty and stenting

Preliminary experience with primary stenting in myocardial infarction has suggested a greater benefit in clinical outcome than has been obtained with direct balloon angioplasty. However, subacute thrombosis (SAT) remains a limitation for this new mode of therapy. In the BENESTENT II Pilot and main trials, the incidence of SAT with the heparin-coated Palmaz-Schatz stent was only 0.15%. Therefore, as a preamble to a large randomized trial, the feasibility and safety of the use of the Heparin-Coated Palmaz-Schatz trade mark Stent in Acute Myocardial Infarction (AMI) was tested in 101 patients enrolled between April and September 1996 in 18 clinical centres. In 101 stent-eligible AMI patients, as dictated by protocol, a heparin-coated stent was implanted. The primary objectives were to determine the in-hospital incidence of major adverse cardiac events (MACE: death, MI, target lesion revascularization) and bleeding complications, while the secondary objectives were the procedural success rate and the MACE, the restenosis and reocclusion rates at 6.5 months. Stent implantation (n 3 129 stents) was successful in 97 patients of the 101 who were included in this trial. During their hospital stay, two patients died and no patient experienced re-infarction, ischaemia prompting re-PTCA or CABG. Four patients suffered a bleeding complication, three major and one minor, of whom three required surgical repair. At 210 days follow-up, 81% of the patients were event free. At 6.5 months restenosis was documented in 18% of the 88 patients who underwent follow-up angiography, including three total occlusions. The results, both with respect to QCA and the occurrence of MACE, compare favourably with studies using elective stenting in both stable and unstable angina patients. As a result of this pilot study, a large randomized trial comparing direct balloon angioplasty with direct stenting in 900 patients with AMI was initiated in December 1996.     

Cost-effective HRMA pre-sequence typing of clone libraries; application to phage display selection

Background  

Methodologies like phage display selection, in vitro mutagenesis and the determination of allelic expression differences include steps where large numbers of clones need to be compared and characterised. In the current study we show that high-resolution melt curve analysis (HRMA) is a simple, cost-saving tool to quickly study clonal variation without prior nucleotide sequence knowledge.     

Cheating is not always punished: killer female plants and pollination by deceit in the dwarf palm Chamaerops humilis

Because the interests of mutualists are not perfectly aligned, conflicts between partners often arise, rendering mutualism unstable by allowing the evolution of cheating. The dwarf palm Chamaerops humilis is engaged in a nursery pollination mutualism with a specific weevil Derelomus chamaeropsis. In exchange for pollen dispersal, dwarf palms provide pollinators with food, shelter and egg-laying sites, but pollinators can develop only within male inflorescences. Here we show that weevils lay eggs in female inflorescences but processes associated with fruit development prevent larval development. The cost imposed by developing larvae probably differs between male and female plants, explaining why only females defend their inflorescences. Female palms thus cheat their pollinating weevil, and pollinators are expected to 'punish' (avoid) them. We found no evidence for such punishment: weevils visit female plants and the duration of visits to male and female inflorescences does not differ. Thus mutualists do not always co-operate and cheating may not be necessarily punished.     

Caffeic Acid Phenylethyl Ester and MG-132 Have Apoptotic and Antiproliferative Effects on Leukemic Cells But Not on Normal Mononuclear Cells

Chemotherapy aims to limit proliferation and induce apoptotic cell death in tumor cells. Owing to blockade of signaling pathways involved in cell survival and proliferation, nuclear factor κB (NF-κB) inhibitors can induce apoptosis in a number of hematological malignancies. The efficacy of conventional chemotherapeutic drugs, such as vincristine (VCR) and doxorubicine (DOX), may be enhanced with combined therapy based on NF-κB modulation. In this study, we evaluated the effect of caffeic acid phenylethyl ester (CAPE) and MG-132, two nonspecific NF-κB inhibitors, and conventional chemotherapeutics drugs DOX and VCR on cell proliferation and apoptosis induction on a lymphoblastoid B-cell line, PL104, established and characterized in our laboratory. CAPE and MG-132 treatment showed a strong antiproliferative effect accompanied by clear cell cycle deregulation and apoptosis induction. Doxorubicine and VCR showed antiproliferative effects similar to those of CAPE and MG-132, although the latter drugs showed an apoptotic rate two-fold higher than DOX and VCR. None of the four compounds showed cytotoxic effect on peripheral mononuclear cells from healthy volunteers. CAPE- and MG-132-treated bone marrow cells from patients with myeloid and lymphoid leukemias showed 69% (P < .001) and 25% decrease (P < .01) in cell proliferation and 42% and 34% (P < .01) apoptosis induction, respectively. Overall, our results indicate that CAPE and MG-132 had a strong and selective apoptotic effect on tumor cells that may be useful in future treatment of hematological neoplasias.     

Mutant huntingtin activates Nrf2-responsive genes and impairs dopamine synthesis in a PC12 model of Huntington's disease

Background  

Huntington's disease is a progressive autosomal dominant neurodegenerative disorder that is caused by a CAG repeat expansion in the HD or Huntington's disease gene. Although micro array studies on patient and animal tissue provide valuable information, the primary effect of mutant huntingtin will inevitably be masked by secondary processes in advanced stages of the disease. Thus, cell models are instrumental to study early, direct effects of mutant huntingtin. mRNA changes were studied in an inducible PC12 model of Huntington's disease, before and after aggregates became visible, to identify groups of genes that could play a role in the early pathology of Huntington's disease.     

Challenges and Solutions in the Development of Genomic Biomarker Panels: A Systematic Phased Approach

In the post-genome era, high throughput gene expression profiling has been successfully used to develop genomic biomarker panels (GBP) that can be integrated into clinical decision making. The development of GBPs in the context of personalized medicine is a scientifically challenging and resource-intense process. It needs to be accomplished in a systematic phased approach to address biological variation related to a clinical phenotype (e.g. disease etiology, gender, etc.) and minimize technical variation (noise). Here we present the methodological aspects of GBP development based on the experience of the Cardiac Allograft Rejection Gene Expression Observation (CARGO) study, a study that lead to the development of a molecular classifier for rejection screening in heart transplant patients.     

Pollinators entering female dioecious figs: why commit suicide?

In the dioecious fig/pollinator mutualism, the female wasps that pollinate figs on female trees die without reproducing, whereas wasps that pollinate figs on male trees produce offspring. Selection should strongly favour wasps that avoid female figs and enter only male figs. Consequently, fig trees would not be pollinated and fig seed production would ultimately cease, leading to extinction of both wasp and fig. We experimentally presented pollinators in the wild (southern India) with a choice between male and female figs of a dioecious fig species, Ficus hispida L. Our results show that wasps do not systematically discriminate between sexes of F. hispida. We propose four hypotheses to explain why wasp choice has not evolved, and how a mutualism is thus maintained in which all wasps that pollinate female figs have zero fitness.