Identification and application of bacterial volatiles to attract a generalist aphid parasitoid: from laboratory to greenhouse assays

BACKGROUND Recent studies have shown that microorganisms emit volatile compounds that affect insect behaviour. However, it remains largely unclear whether microbes can be exploited as a source of attractants to improve biological control of insect pests. In this study, we used a combination of coupled gas chromatography‐electroantennography (GC–EAG) and Y‐tube olfactometer bioassays to identify attractive compounds in the volatile extracts of three bacterial strains that are associated with the habitat of the generalist aphid parasitoid Aphidius colemani, and to create mixtures of synthetic compounds to find attractive blends for A. colemani. Subsequently, the most attractive blend was evaluated in two‐choice cage experiments under greenhouse conditions. RESULTS GC–EAG analysis revealed 20 compounds that were linked to behaviourally attractive bacterial strains. A mixture of two EAG‐active compounds, styrene and benzaldehyde applied at a respective dose of 1 μg and 10 ng, was more attractive than the single compounds or the culture medium of the bacteria in Y‐tube olfactometer bioassays. Application of this synthetic mixture under greenhouse conditions resulted in significant attraction of the parasitoids, and outperformed application of the bacterial culture medium. CONCLUSION Compounds isolated from bacterial blends were capable of attracting parasitoids both in laboratory and greenhouse assays, indicating that microbial cultures are an effective source of insect attractants. This opens new opportunities to attract and retain natural enemies of pest species and to enhance biological pest control

"It's making contacts" : notions of social capital and implications for widening access to medical education

Acknowledgements Our thanks to the Medical Schools Council (MSC) of the UK for funding Study A; REACH Scotland for funding Study B; and Queen Mary University of London, and to the medical school applicants and students who gave their time to be interviewed. Our thanks also to Dr Sean Zhou and Dr Sally Curtis, and Manjul Medhi, for their help with data collection for studies A and B respectively. Our thanks also to Dr Lara Varpio, Uniformed Services University of the USA, for her advice and guidance on collating data sets and her comments on the draft manuscript.Peer reviewedPublisher PD

Ciliary Neurotrophic Factor Protects Striatal Neurons against Excitotoxicity by Enhancing Glial Glutamate Uptake

Ciliary neurotrophic factor (CNTF) is a potent neuroprotective cytokine in different animal models of glutamate-induced excitotoxicity, although its action mechanisms are still poorly characterized. We tested the hypothesis that an increased function of glial glutamate transporters (GTs) could underlie CNTF-mediated neuroprotection. We show that neuronal loss induced by in vivo striatal injection of the excitotoxin quinolinic acid (QA) was significantly reduced (by ∼75%) in CNTF-treated animals. In striatal slices, acute QA application dramatically inhibited corticostriatal field potentials (FPs), whose recovery was significantly higher in CNTF rats compared to controls (∼40% vs. ∼7%), confirming an enhanced resistance to excitotoxicity. The GT inhibitor dl-threo-β-benzyloxyaspartate greatly reduced FP recovery in CNTF rats, supporting the role of GT in CNTF-mediated neuroprotection. Whole-cell patch-clamp recordings from striatal medium spiny neurons showed no alteration of basic properties of striatal glutamatergic transmission in CNTF animals, but the increased effect of a low-affinity competitive glutamate receptor antagonist (γ-d-glutamylglycine) also suggested an enhanced GT function. These data strongly support our hypothesis that CNTF is neuroprotective via an increased function of glial GTs, and further confirms the therapeutic potential of CNTF for the clinical treatment of progressive neurodegenerative diseases involving glutamate overflow

Effect of TENS on pain in relation to central sensitization in patients with osteoarthritis of the knee: study protocol of a randomized controlled trial

<p>Abstract</p> <p>Background</p> <p>Central sensitization has recently been documented in patients with knee osteoarthritis (OAk). So far, the presence of central sensitization has not been considered as a confounding factor in studies assessing the pain inhibitory effect of tens on osteoarthritis of the knee. The purpose of this study is to explore the pain inhibitory effect of burst tens in OAk patients and to explore the prognostic value of central sensitization on the pain inhibitory effect of tens in OAk patients.</p> <p>Methods</p> <p>Patients with knee pain due to OAk will be recruited through advertisements in local media. Temporal summation, before and after a heterotopic noxious conditioning stimulation, will be measured. In addition, pain on a numeric rating score, WOMAC subscores for pain and function and global perceived effect will be assessed. Patients will be randomly allocated to one of two treatment groups (tens, sham tens). Follow-up measurements will be scheduled after a period of 6 and 12 weeks.</p> <p>Discussion</p> <p>Tens influences pain through the electrical stimulation of low-threshold A-beta cutaneous fibers. The responsiveness of central pain-signaling neurons of centrally sensitized OAk patients may be augmented to the input of these electrical stimuli. This would encompass an adverse therapy effect of tens. To increase treatment effectiveness it might be interesting to identify a subgroup of symptomatic OAk patients, i.e., non-sensitized patients, who are likely to benefit from burst tens.</p> <p>Trial Registration</p> <p>ClinicalTrials.gov: <a href="http://www.clinicaltrials.gov/ct2/show/NCT01390285">NCT01390285</a></p

Huntington's disease and its therapeutic target genes: a global functional profile based on the HD Research Crossroads database.

BACKGROUND: Huntington's disease (HD) is a fatal progressive neurodegenerative disorder caused by the expansion of the polyglutamine repeat region in the huntingtin gene. Although the disease is triggered by the mutation of a single gene, intensive research has linked numerous other genes to its pathogenesis. To obtain a systematic overview of these genes, which may serve as therapeutic targets, CHDI Foundation has recently established the HD Research Crossroads database. With currently over 800 cataloged genes, this web-based resource constitutes the most extensive curation of genes relevant to HD. It provides us with an unprecedented opportunity to survey molecular mechanisms involved in HD in a holistic manner. METHODS: To gain a synoptic view of therapeutic targets for HD, we have carried out a variety of bioinformatical and statistical analyses to scrutinize the functional association of genes curated in the HD Research Crossroads database. In particular, enrichment analyses were performed with respect to Gene Ontology categories, KEGG signaling pathways, and Pfam protein families. For selected processes, we also analyzed differential expression, using published microarray data. Additionally, we generated a candidate set of novel genetic modifiers of HD by combining information from the HD Research Crossroads database with previous genome-wide linkage studies. RESULTS: Our analyses led to a comprehensive identification of molecular mechanisms associated with HD. Remarkably, we not only recovered processes and pathways, which have frequently been linked to HD (such as cytotoxicity, apoptosis, and calcium signaling), but also found strong indications for other potentially disease-relevant mechanisms that have been less intensively studied in the context of HD (such as the cell cycle and RNA splicing, as well as Wnt and ErbB signaling). For follow-up studies, we provide a regularly updated compendium of molecular mechanism, that are associated with HD, at http://hdtt.sysbiolab.eu Additionally, we derived a candidate set of 24 novel genetic modifiers, including histone deacetylase 3 (HDAC3), metabotropic glutamate receptor 1 (GRM1), CDK5 regulatory subunit 2 (CDK5R2), and coactivator 1ß of the peroxisome proliferator-activated receptor gamma (PPARGC1B). CONCLUSIONS: The results of our study give us an intriguing picture of the molecular complexity of HD. Our analyses can be seen as a first step towards a comprehensive list of biological processes, molecular functions, and pathways involved in HD, and may provide a basis for the development of more holistic disease models and new therapeutics

Decreased Striatal RGS2 Expression Is Neuroprotective in Huntington's Disease (HD) and Exemplifies a Compensatory Aspect of HD-Induced Gene Regulation

The molecular phenotype of Huntington's disease (HD) is known to comprise highly reproducible changes in gene expression involving striatal signaling genes. Here we test whether individual changes in striatal gene expression are capable of mitigating HD-related neurotoxicity.We used protein-encoding and shRNA-expressing lentiviral vectors to evaluate the effects of RGS2, RASD2, STEP and NNAT downregulation in HD. Of these four genes, only RGS2 and RASD2 modified mutant htt fragment toxicity in cultured rat primary striatal neurons. In both cases, disease modulation was in the opposite of the predicted direction: whereas decreased expression of RGS2 and RASD2 was associated with the HD condition, restoring expression enhanced degeneration of striatal cells. Conversely, silencing of RGS2 or RASD2 enhanced disease-related changes in gene expression and resulted in significant neuroprotection. These results indicate that RGS2 and RASD2 downregulation comprises a compensatory response that allows neurons to better tolerate huntingtin toxicity. Assessment of the possible mechanism of RGS2-mediated neuroprotection showed that RGS2 downregulation enhanced ERK activation. These results establish a novel link between the inhibition of RGS2 and neuroprotective modulation of ERK activity.Our findings both identify RGS2 downregulation as a novel compensatory response in HD neurons and suggest that RGS2 inhibition might be considered as an innovative target for neuroprotective drug development

Effects of Subthalamic Nucleus Lesions and Stimulation upon Corticostriatal Afferents in the 6-Hydroxydopamine-Lesioned Rat

Abnormalities of striatal glutamate neurotransmission may play a role in the pathophysiology of Parkinson's disease and may respond to neurosurgical interventions, specifically stimulation or lesioning of the subthalamic nucleus (STN). The major glutamatergic afferent pathways to the striatum are from the cortex and thalamus, and are thus likely to be sources of striatal neuronally-released glutamate. Corticostriatal terminals can be distinguished within the striatum at the electron microscopic level as their synaptic vesicles contain the vesicular glutamate transporter, VGLUT1. The majority of terminals which are immunolabeled for glutamate but are not VGLUT1 positive are likely to be thalamostriatal afferents. We compared the effects of short term, high frequency, STN stimulation and lesioning in 6-hydroxydopamine (6OHDA)-lesioned rats upon striatal terminals immunolabeled for both presynaptic glutamate and VGLUT1. 6OHDA lesions resulted in a small but significant increase in the proportions of VGLUT1-labeled terminals making synapses on dendritic shafts rather than spines. STN stimulation for one hour, but not STN lesions, increased the proportion of synapses upon spines. The density of presynaptic glutamate immuno-gold labeling was unchanged in both VGLUT1-labeled and -unlabeled terminals in 6OHDA-lesioned rats compared to controls. Rats with 6OHDA lesions+STN stimulation showed a decrease in nerve terminal glutamate immuno-gold labeling in both VGLUT1-labeled and -unlabeled terminals. STN lesions resulted in a significant decrease in the density of presynaptic immuno-gold-labeled glutamate only in VGLUT1-labeled terminals. STN interventions may achieve at least part of their therapeutic effect in PD by normalizing the location of corticostriatal glutamatergic terminals and by altering striatal glutamatergic neurotransmission

The HIV Matrix Protein p17 Subverts Nuclear Receptors Expression and Induces a STAT1-Dependent Proinflammatory Phenotype in Monocytes

BACKGROUND: Long-term remission of HIV-1 disease can be readily achieved by combinations of highly effective antiretroviral therapy (HAART). However, a residual persistent immune activation caused by circulating non infectious particles or viral proteins is observed under HAART and might contribute to an higher risk of non-AIDS pathologies and death in HIV infected persons. A sustained immune activation supports lipid dysmetabolism and increased risk for development of accelerated atehrosclerosis and ischemic complication in virologically suppressed HIV-infected persons receiving HAART. AIM: While several HIV proteins have been identified and characterized for their ability to maintain immune activation, the role of HIV-p17, a matrix protein involved in the viral replication, is still undefined. RESULTS: Here, we report that exposure of macrophages to recombinant human p17 induces the expression of proinflammatory and proatherogenic genes (MCP-1, ICAM-1, CD40, CD86 and CD36) while downregulating the expression of nuclear receptors (FXR and PPARγ) that counter-regulate the proinflammatory response and modulate lipid metabolism in these cells. Exposure of macrophage cell lines to p17 activates a signaling pathway mediated by Rack-1/Jak-1/STAT-1 and causes a promoter-dependent regulation of STAT-1 target genes. These effects are abrogated by sera obtained from HIV-infected persons vaccinated with a p17 peptide. Ligands for FXR and PPARγ counteract the effects of p17. CONCLUSIONS: The results of this study show that HIV p17 highjacks a Rack-1/Jak-1/STAT-1 pathway in macrophages, and that the activation of this pathway leads to a simultaneous dysregulation of immune and metabolic functions. The binding of STAT-1 to specific responsive elements in the promoter of PPARγ and FXR and MCP-1 shifts macrophages toward a pro-atherogenetic phenotype characterized by high levels of expression of the scavenger receptor CD36. The present work identifies p17 as a novel target in HIV therapy and grounds the development of anti-p17 small molecules or vaccines