Plant Community Diversity Influences Allocation to Direct Chemical Defence in Plantago lanceolata

Background: Forecasting the consequences of accelerating rates of changes in biodiversity for ecosystem functioning requires a mechanistic understanding of the relationships between the structure of biological communities and variation in plant functional characteristics. So far, experimental data of how plant species diversity influences the investment of individual plants in direct chemical defences against herbivores and pathogens is lacking. Methodology/Principal Findings: We used Plantago lanceolata as a model species in experimental grasslands differing in species richness and composition (Jena Experiment) to investigate foliar concentrations of the iridoid glycosides (IG), catalpol and its biosynthetic precursor aucubin. Total IG and aucubin concentrations decreased, while catalpol concentrations increased with increasing plant diversity in terms of species or functional group richness. Negative plant diversity effects on total IG and aucubin concentrations correlated with increasing specific leaf area of P. lanceolata, suggesting that greater allocation to light acquisition reduced the investment into these carbon-based defence components. In contrast, increasing leaf nitrogen concentrations best explained increasing concentrations of the biosynthetically more advanced IG, catalpol. Observed levels of leaf damage explained a significant proportion of variation in total IG and aucubin concentrations, but did not account for variance in catalpol concentrations. Conclusions/Significance: Our results clearly show that plants growing in communities of varying species richness an

Challenges for Allergy Diagnosis in Regions with Complex Pollen Exposures

Over the past few decades, significant scientific progress has influenced clinical allergy practice. The biological standardization of extracts was followed by the massive identification and characterization of new allergens and their progressive use as diagnostic tools including allergen micro arrays that facilitate the simultaneous testing of more than 100 allergen components. Specific diagnosis is the basis of allergy practice and is always aiming to select the best therapeutic or avoidance intervention. As a consequence, redundant or irrelevant information might be adding unnecessary cost and complexity to daily clinical practice. A rational use of the different diagnostic alternatives would allow a significant improvement in the diagnosis and treatment of allergic patients, especially for those residing in complex pollen exposure areas

Long non-coding RNAs: spatial amplifiers that control nuclear structure and gene expression

Over the past decade, it has become clear that mammalian genomes encode thousands of long non-coding RNAs (lncRNAs), many of which are now implicated in diverse biological processes. Recent work studying the molecular mechanisms of several key examples — including Xist, which orchestrates X chromosome inactivation — has provided new insights into how lncRNAs can control cellular functions by acting in the nucleus. Here we discuss emerging mechanistic insights into how lncRNAs can regulate gene expression by coordinating regulatory proteins, localizing to target loci and shaping three-dimensional (3D) nuclear organization. We explore these principles to highlight biological challenges in gene regulation, in which lncRNAs are well-suited to perform roles that cannot be carried out by DNA elements or protein regulators alone, such as acting as spatial amplifiers of regulatory signals in the nucleus

Morphological characterization of bushy cells and their inputs in the laboratory mouse (Mus musculus) anteroventral cochlear nucleus.

PMC3753269Spherical and globular bushy cells of the AVCN receive huge auditory nerve endings specialized for high fidelity neural transmission in response to acoustic events. Recent studies in mice and other rodent species suggest that the distinction between bushy cell subtypes is not always straightforward. We conducted a systematic investigation of mouse bushy cells along the rostral-caudal axis in an effort to understand the morphological variation that gives rise to reported response properties in mice. We combined quantitative light and electron microscopy to investigate variations in cell morphology, immunostaining, and the distribution of primary and non-primary synaptic inputs along the rostral-caudal axis. Overall, large regional differences in bushy cell characteristics were not found; however, rostral bushy cells received a different complement of axosomatic input compared to caudal bushy cells. The percentage of primary auditory nerve terminals was larger in caudal AVCN, whereas non-primary excitatory and inhibitory inputs were more common in rostral AVCN. Other ultrastructural characteristics of primary auditory nerve inputs were similar across the rostral and caudal AVCN. Cross sectional area, postsynaptic density length and curvature, and mitochondrial volume fraction were similar for axosomatic auditory nerve terminals, although rostral auditory nerve terminals contained a greater concentration of synaptic vesicles near the postsynaptic densities. These data demonstrate regional differences in synaptic organization of inputs to mouse bushy cells rather than the morphological characteristic of the cells themselves.JH Libraries Open Access Fun

Frequent HIV testing among participants of a routine HIV testing program

Massachusetts developed a routine HIV testing program in four sites from January–September 2002. Of the 2,502 patients tested, 453 (18.1%) reported ≥2 HIV tests within the prior three years. In multivariate analyses, frequent HIV testing was associated with younger age (18–30 years, OR = 1.42), a history of injection drug use (OR = 6.35), and men who had sex with men (OR = 3.49). Participants who reported multiple sexual partners (OR = 2.17) and high risk sexual behavior (OR = 2.02) were significantly more likely to have had a prior HIV test. Patients whose HIV risk was unknown had the highest association with frequent testing (OR = 13.18). Because characteristics of frequent HIV testers may inform behavioral interventions, there is a need to understand the motivation for repeatedly accessing HIV testing services

Crystal Methamphetamine Use and Sexual Risk Behaviors among HIV-Positive and HIV-Negative Men Who Have Sex with Men in South Florida

Using data collected through venue-based sampling in South Florida from 2004 to 2005 as part of the Centers for Disease Control and Prevention-funded National HIV Behavioral Surveillance Among Men Who Have Sex with Men, we estimate the prevalence of crystal methamphetamine use and its association with high-risk sexual behaviors among a large and diverse sample of men who have sex with men (MSM) residing in South Florida. We also examine how these associations differ between HIV-positive and HIV-negative men. Bivariate analyses were used to assess the characteristics of study participants and their sexual risk behaviors by drug use and self-reported HIV status group. Of 946 MSM participants in South Florida, 18% reported crystal methamphetamine use in the past 12 months. Regardless of self-reported HIV status, crystal methamphetamine users were more likely to report high-risk sexual behaviors, an increased number of non-main sex partners, and being high on drugs and/or alcohol at last sex act with a non-main partner. Our findings indicate that crystal methamphetamine use is prevalent among the MSM population in South Florida, and this prevalence rate is similar, if not higher, than that found in US cities that have been long recognized for having a high rate of crystal methamphetamine use among their MSM populations. Notably, the use of crystal methamphetamine among both HIV-positive and HIV-negative MSM is associated with increased HIV-related risk behaviors