Food for pollinators: quantifying the nectar and pollen resources of urban flower meadows

Planted meadows are increasingly used to improve the biodiversity and aesthetic amenity value of urban areas. Although many ‘pollinator-friendly’ seed mixes are available, the floral resources these provide to flower-visiting insects, and how these change through time, are largely unknown. Such data are necessary to compare the resources provided by alternative meadow seed mixes to each other and to other flowering habitats. We used quantitative surveys of over 2 million flowers to estimate the nectar and pollen resources offered by two exemplar commercial seed mixes (one annual, one perennial) and associated weeds grown as 300m2 meadows across four UK cities, sampled at six time points between May and September 2013. Nectar sugar and pollen rewards per flower varied widely across 65 species surveyed, with native British weed species (including dandelion, Taraxacum agg.) contributing the top five nectar producers and two of the top ten pollen producers. Seed mix species yielding the highest rewards per flower included Leontodon hispidus, Centaurea cyanus and C. nigra for nectar, and Papaver rhoeas, Eschscholzia californica and Malva moschata for pollen. Perennial meadows produced up to 20x more nectar and up to 6x more pollen than annual meadows, which in turn produced far more than amenity grassland controls. Perennial meadows produced resources earlier in the year than annual meadows, but both seed mixes delivered very low resource levels early in the year and these were provided almost entirely by native weeds. Pollen volume per flower is well predicted statistically by floral morphology, and nectar sugar mass and pollen volume per unit area are correlated with flower counts, raising the possibility that resource levels can be estimated for species or habitats where they cannot be measured directly. Our approach does not incorporate resource quality information (for example, pollen protein or essential amino acid content), but can easily do so when suitable data exist. Our approach should inform the design of new seed mixes to ensure continuity in floral resource availability throughout the year, and to identify suitable species to fill resource gaps in established mixes

Inferring learning from big data:The importance of a transdisciplinary and multidimensional approach

The use of big data in higher education has evolved rapidly with a focus on the practical application of new tools and methods for supporting learning. In this paper, we depart from the core emphasis on application and delve into a mostly neglected aspect of the big data conversation in higher education. Drawing on developments in cognate disciplines, we analyse the inherent difficulties in inferring the complex phenomenon that is learning from big datasets. This forms the basis of a discussion about the possibilities for systematic collaboration across different paradigms and disciplinary backgrounds in interpreting big data for enhancing learning. The aim of this paper is to provide the foundation for a research agenda, where differing conceptualisations of learning become a strength in interpreting patterns in big datasets, rather than a point of contention

Discovery of New Hydrothermal Activity and Chemosynthetic Fauna on the Central Indian Ridge at 18°–20°S

Indian Ocean hydrothermal vents are believed to represent a novel biogeographic province, and are host to many novel genera and families of animals, potentially indigenous to Indian Ocean hydrothermal systems. In particular, since its discovery in 2001, much attention has been paid to a so-called ‘scaly-foot’ gastropod because of its unique iron-sulfide-coated dermal sclerites and the chemosynthetic symbioses in its various tissues. Despite increasing interest in the faunal assemblages at Indian Ocean hydrothermal vents, only two hydrothermal vent fields have been investigated in the Indian Ocean. Here we report two newly discovered hydrothermal vent fields, the Dodo and Solitaire fields, which are located in the Central Indian Ridge (CIR) segments 16 and 15, respectively. Chemosynthetic faunal communities at the Dodo field are emaciated in size and composition. In contrast, at the Solitaire field, we observed faunal communities that potentially contained almost all genera found at CIR hydrothermal environments to date, and even identified previously unreported taxa. Moreover, a new morphotype of ‘scaly-foot’ gastropod has been found at the Solitaire field. The newly discovered ‘scaly-foot’ gastropod has similar morphological and anatomical features to the previously reported type that inhabits the Kairei field, and both types of ‘scaly-foot’ gastropods genetically belong to the same species according to analyses of their COI gene and nuclear SSU rRNA gene sequences. However, the new morphotype completely lacks an iron-sulfide coating on the sclerites, which had been believed to be a novel feature restricted to ‘scaly-foot’ gastropods. Our new findings at the two newly discovered hydrothermal vent sites provide important insights into the biodiversity and biogeography of vent-endemic ecosystems in the Indian Ocean

A Switch in Hepatic Cortisol Metabolism across the Spectrum of Non Alcoholic Fatty Liver Disease

Context: Non alcoholic fatty liver disease (NAFLD) is the hepatic manifestation of the metabolic syndrome. NAFLD represents a spectrum of liver disease ranging from reversible hepatic steatosis, to non alcoholic steato-hepatitis (NASH) and cirrhosis. The potential role of glucocorticoids (GC) in the pathogenesis of NAFLD is highlighted in patients with GC excess, Cushing's syndrome, who develop central adiposity, insulin resistance and in 20% of cases, NAFLD. Although in most cases of NAFLD, circulating cortisol levels are normal, hepatic cortisol availability is controlled by enzymes that regenerate cortisol (F) from inactive cortisone (E) (11β-hydroxysteroid dehydrogenase type 1, 11β-HSD1), or inactivate cortisol through A-ring metabolism (5α- and 5β-reductase, 5αR and 5βR). Objective and Methods: In vitro studies defined 11β-HSD1 expression in normal and NASH liver samples. We then characterised hepatic cortisol metabolism in 16 patients with histologically proven NAFLD compared to 32 obese controls using gas chromatographic analysis of 24 hour urine collection and plasma cortisol generation profile following oral cortisone. Results: In patients with steatosis 5αR activity was increased, with a decrease in hepatic 11β-HSD1 activity. Total cortisol metabolites were increased in this group consistent with increased GC production rate. In contrast, in patients with NASH, 11β-HSD1 activity was increased both in comparison to patients with steatosis, and controls. Endorsing these findings, 11β-HSD1 mRNA and immunostaining was markedly increased in NASH patients in peri septal hepatocytes and within CD68 positive macrophages within inflamed cirrhotic septa. Conclusion: Patients with hepatic steatosis have increased clearance and decreased hepatic regeneration of cortisol and we propose that this may represent a protective mechanism to decrease local GC availability to preserve hepatic metabolic phenotype. With progression to NASH, increased 11β-HSD1 activity and consequent cortisol regeneration may serve to limit hepatic inflammation

H2B ubiquitylation is part of chromatin architecture that marks exon-intron structure in budding yeast

<p>Abstract</p> <p>Background</p> <p>The packaging of DNA into chromatin regulates transcription from initiation through 3' end processing. One aspect of transcription in which chromatin plays a poorly understood role is the co-transcriptional splicing of pre-mRNA.</p> <p>Results</p> <p>Here we provide evidence that H2B monoubiquitylation (H2BK123ub1) marks introns in <it>Saccharomyces cerevisiae</it>. A genome-wide map of H2BK123ub1 in this organism reveals that this modification is enriched in coding regions and that its levels peak at the transcribed regions of two characteristic subgroups of genes. First, long genes are more likely to have higher levels of H2BK123ub1, correlating with the postulated role of this modification in preventing cryptic transcription initiation in ORFs. Second, genes that are highly transcribed also have high levels of H2BK123ub1, including the ribosomal protein genes, which comprise the majority of intron-containing genes in yeast. H2BK123ub1 is also a feature of introns in the yeast genome, and the disruption of this modification alters the intragenic distribution of H3 trimethylation on lysine 36 (H3K36me3), which functionally correlates with alternative RNA splicing in humans. In addition, the deletion of genes encoding the U2 snRNP subunits, Lea1 or Msl1, in combination with an <it>htb-K123R </it>mutation, leads to synthetic lethality.</p> <p>Conclusion</p> <p>These data suggest that H2BK123ub1 facilitates cross talk between chromatin and pre-mRNA splicing by modulating the distribution of intronic and exonic histone modifications.</p

Large Tandem, Higher Order Repeats and Regularly Dispersed Repeat Units Contribute Substantially to Divergence Between Human and Chimpanzee Y Chromosomes

Comparison of human and chimpanzee genomes has received much attention, because of paramount role for understanding evolutionary step distinguishing us from our closest living relative. In order to contribute to insight into Y chromosome evolutionary history, we study and compare tandems, higher order repeats (HORs), and regularly dispersed repeats in human and chimpanzee Y chromosome contigs, using robust Global Repeat Map algorithm. We find a new type of long-range acceleration, human-accelerated HOR regions. In peripheral domains of 35mer human alphoid HORs, we find riddled features with ten additional repeat monomers. In chimpanzee, we identify 30mer alphoid HOR. We construct alphoid HOR schemes showing significant human-chimpanzee difference, revealing rapid evolution after human-chimpanzee separation. We identify and analyze over 20 large repeat units, most of them reported here for the first time as: chimpanzee and human ~1.6 kb 3mer secondary repeat unit (SRU) and ~23.5 kb tertiary repeat unit (~0.55 kb primary repeat unit, PRU); human 10848, 15775, 20309, 60910, and 72140 bp PRUs; human 3mer SRU (~2.4 kb PRU); 715mer and 1123mer SRUs (5mer PRU); chimpanzee 5096, 10762, 10853, 60523 bp PRUs; and chimpanzee 64624 bp SRU (10853 bp PRU). We show that substantial human-chimpanzee differences are concentrated in large repeat structures, at the level of as much as ~70% divergence, sizably exceeding previous numerical estimates for some selected noncoding sequences. Smeared over the whole sequenced assembly (25 Mb) this gives ~14% human--chimpanzee divergence. This is significantly higher estimate of divergence between human and chimpanzee than previous estimates.Comment: 22 pages, 7 figures, 12 tables. Published in Journal of Molecular Evolutio

Resource use in two contrasting habitat types raises different challenges for the conservation of the dryad butterfly Minois dryas

The suitability of any location for a given species is determined by the available resources. However, there are many species that occur in more than one habitat type and their successful conservation may be particularly difficult. The dryad Minois dryas, a locally endangered butterfly, occurs in two contrasting habitats-xerothemic and wet grasslands. We investigated the influence of various habitat characteristics, such as vegetation height, grass cover, proximity of shrubs, plant species composition, Ellenberg indices of trophic and microclimatic conditions, on the microhabitat selection by the species. The nectaring of randomly selected butterflies was observed and habitat characteristics were compared at random points within the meadow and at the butterfly’s nectaring and resting places. The butterflies generally preferred to stay close to shrubs and avoided invasive goldenrods. Thermal conditions and the availability of nectar plants were the factors limiting the dryad’s use of wet grassland. In xerothermic habitats grass cover affected the distribution of butterflies. Concerning the availability of larval host plants, wet meadows proved potentially more favourable, whereas nectar resources for adults were more abundant in xerothermic grasslands. Based on our findings, conservation strategies for this butterfly must differ in the two habitats. Rotational mowing in xerothermic grasslands and the removal of invasive goldenrods in wet grasslands are the recommended actions. At a larger spatial scale, a habitat mosaic composed of xerothermic and wet grasslands in close proximity would seem to be the most suitable areas for the conservation of the dryad

Histone deacetylase inhibitors: clinical implications for hematological malignancies

Histone modifications have widely been implicated in cancer development and progression and are potentially reversible by drug treatments. The N-terminal tails of each histone extend outward through the DNA strand containing amino acid residues modified by posttranslational acetylation, methylation, and phosphorylation. These modifications change the secondary structure of the histone protein tails in relation to the DNA strands, increasing the distance between DNA and histones, and thus allowing accessibility of transcription factors to gene promoter regions. A large number of HDAC inhibitors have been synthesized in the last few years, most being effective in vitro, inducing cancer cells differentiation or cell death. The majority of the inhibitors are in clinical trials, unlike the suberoylanilide hydroxamic acid, a pan-HDACi, and Romidepsin (FK 228), a class I-selective HDACi, which are only approved in the second line treatment of refractory, persistent or relapsed cutaneous T-cell lymphoma, and active in approximately 150 clinical trials, in monotherapy or in association. Preclinical studies investigated the use of these drugs in clinical practice, as single agents and in combination with chemotherapy, hypomethylating agents, proteasome inhibitors, and MTOR inhibitors, showing a significant effect mostly in hematological malignancies. The aim of this review is to focus on the biological features of these drugs, analyzing the possible mechanism(s) of action and outline an overview on the current use in the clinical practice