Infochemicals influencing the host foraging behaviour of Dahlbominus fuscipennis, a pupal parasitoid of the European spruce sawfly (Gilpinia hercyniae)

The chalcidoid wasp Dahlbominus fuscipennis Zett. (Hymenoptera: Eulophidae) parasitises pupae of the European spruce sawfly Gilpinia hercyniae Htg. (Hymenoptera: Diprionidae). In this parasitoid-host system the role of infochemicals for successful parasitisation was studied. Olfactometer experiments and dual choice bioassays in petri dishes showed that D. fuscipennis was not attracted by volatiles from a plant-host complex consisting of spruce, sawfly larvae and pupae. On the other hand, odours from needles of Picea abies (L.), that were collected from the ground, attracted D. fuscipennis to the habitat of the sawfly. Volatiles from host pupae were not attractive, whereas a contact kairomone from sawfly pupae elicited frequent antennal drumming, a behaviour that indicates host recognition. This contact kairomone was extracted with methanol from the outer cocoon layer of the pupa. The kairomone is not produced by the silk glands of the last instar larva spinning the cocoon, since a methanolic extract of silk gland secretion did not elicit any response in D. fuscipennis. Further bioassays revealed that non-volatile components of the integument of the prepupa within the cocoon also elicited antennal drumming. We suggest that chemicals of the prepupal integument diffuse from inside the cocoon to the outside where they inform the parasitoid on the suitability of the host.     

Overexpression of {gamma}-Glutamylcysteine Synthetase, but not of Glutathione Synthetase, Elevates Glutathione Allocation in the Phloem of Transgenic Poplar Trees

Phloem exudates were collected along the tree axis at differentheights of wild type and transgenic poplar. Over-expressionof bacterial     

Female Gender Is a Social Determinant of Diabetes in the Caribbean: A Systematic Review and Meta-Analysis

BackgroundDiabetes (DM) is estimated to affect 10–15% of the adult population in the Caribbean. Preventive efforts require population wide measures to address its social determinants. We undertook a systematic review to determine current knowledge about the social distribution of diabetes, its risk factors and major complications in the Caribbean. This paper describes our findings on the distribution by gender.MethodsWe searched Medline, Embase and five databases through the Virtual Health Library, for Caribbean studies published between 2007 and 2013 that described the distribution by gender for: known risk factors for Type 2 DM, prevalence of DM, and DM control or complications. PRISMA guidance on reporting systematic reviews on health equity was followed. Only quantitative studies (n>50) were included; each was assessed for risk of bias. Meta-analyses were performed, where appropriate, on studies with a low or medium risk of bias, using random effects models.ResultsWe found 50 articles from 27 studies, yielding 118 relationships between gender and the outcomes. Women were more likely to have DM, obesity, be less physically active but less likely to smoke. In meta-analyses of good quality population-based studies odds ratios for women vs. men for DM, obesity and smoking were: 1.65 (95% CI 1.43, 1.91), 3.10 (2.43, 3.94), and 0.24 (0.17, 0.34). Three studies found men more likely to have better glycaemic control but only one achieved statistical significance.

Conclusion and Implications

Female gender is a determinant of DM prevalence in the Caribbean. In the vast majority of world regions women are at a similar or lower risk of type 2 diabetes than men, even when obesity is higher in women. Caribbean female excess of diabetes may be due to a much greater excess of risk factors in women, especially obesity. These findings have major implications for preventive policies and research.     

Hatching late in the season requires flexibility in the timing of song learning

Most songbirds learn their songs from adult tutors, who can be their father or other male conspecifics. However, the variables that control song learning in a natural social context are largely unknown. We investigated whether the time of hatching of male domesticated canaries has an impact on their song development and on the neuroendocrine parameters of the song control system. Average age difference between early- and late-hatched males was 50 days with a maximum of 90 days. Song activity of adult tutor males decreased significantly during the breeding season. While early-hatched males were exposed to tutor songs for on average the first 99 days, late-hatched peers heard adult song only during the first 48 days of life. Remarkably, although hatching late in the season negatively affected body condition, no differences between both groups of males were found in song characteristics either in autumn or in the following spring. Similarly, hatching date had no effect on song nucleus size and circulating testosterone levels. Our data suggest that late-hatched males must have undergone accelerated song development. Furthermore, the limited tutor song exposure did not affect adult song organization and song performance.     

Yield‐biodiversity trade‐off in patchy fields of Miscanthus × giganteus

Increasing crop productivity to meet rising demands for food and energy, but doing so in an environmentally sustainable manner, is one of the greatest challenges for agriculture to date. In Ireland, Miscanthus × giganteus has the potential to become a major feedstock for bioenergy production, but the economic feasibility of its cultivation depends on high yields. Miscanthus fields can have a large number of gaps in crop cover, adversely impacting yield and hence economic viability. Predominantly positive effects of Miscanthus on biodiversity reported from previous research might be attributable to high crop patchiness, particularly during the establishment phase. The aim of this research was to assess crop patchiness on a field scale and to analyse the relationship between Miscanthus yield and species richness and abundance of selected taxa of farmland wildlife. For 14 Miscanthus fields at the end of their establishment phase (4–5 years after planting), which had been planted either on improved grassland (MG) or tilled arable land (MT), we determined patchiness of the crop cover, percentage light penetration (LP) to the lower canopy, Miscanthus shoot density and height, vascular plants and epigeic arthropods. Plant species richness and noncrop vegetation cover in Miscanthus fields increased with increasing patchiness, due to higher levels of LP to the lower canopy. The species richness of ground beetles and the activity density of spiders followed the increase in vegetation cover. Plant species richness and activity density of spiders on both MT and MG fields, as well as vegetation cover and activity density of ground beetles on MG fields, were negatively associated with Miscanthus yield. In conclusion, positive effects of Miscanthus on biodiversity can diminish with increasing productivity. This matter needs to be considered when assessing the relative ecological impacts of developing biomass crops in comparison with other land use.     

Pre-Analytical Sample Quality: Metabolite Ratios as an Intrinsic Marker for Prolonged Room Temperature Exposure of Serum Samples

Advances in the “omics” field bring about the need for a high number of good quality samples. Many omics studies take advantage of biobanked samples to meet this need. Most of the laboratory errors occur in the pre-analytical phase. Therefore evidence-based standard operating procedures for the pre-analytical phase as well as markers to distinguish between ‘good’ and ‘bad’ quality samples taking into account the desired downstream analysis are urgently needed. We studied concentration changes of metabolites in serum samples due to pre-storage handling conditions as well as due to repeated freeze-thaw cycles. We collected fasting serum samples and subjected aliquots to up to four freeze-thaw cycles and to pre-storage handling delays of 12, 24 and 36 hours at room temperature (RT) and on wet and dry ice. For each treated aliquot, we quantified 127 metabolites through a targeted metabolomics approach. We found a clear signature of degradation in samples kept at RT. Storage on wet ice led to less pronounced concentration changes. 24 metabolites showed significant concentration changes at RT. In 22 of these, changes were already visible after only 12 hours of storage delay. Especially pronounced were increases in lysophosphatidylcholines and decreases in phosphatidylcholines. We showed that the ratio between the concentrations of these molecule classes could serve as a measure to distinguish between ‘good’ and ‘bad’ quality samples in our study. In contrast, we found quite stable metabolite concentrations during up to four freeze-thaw cycles. We concluded that pre-analytical RT handling of serum samples should be strictly avoided and serum samples should always be handled on wet ice or in cooling devices after centrifugation. Moreover, serum samples should be frozen at or below -80°C as soon as possible after centrifugation.     

Development and Evaluation of New Microemulsion-Based Hydrogel Formulations for Topical Delivery of Fluconazole

The aim of the present investigation was to develop and evaluate microemulsion-loaded hydrogels (MEHs) for the topical delivery of fluconazole (FZ). The solubility of FZ in oils, surfactants and cosurfactants was evaluated to identify the components of the microemulsion. The pseudo-ternary phase diagrams were constructed using the novel phase diagram by micro-plate dilution method. Carbopol EDT 2020 was used to convert FZ-loaded microemulsions into gel form without affecting their structure. The selected microemulsions were assessed for globule size, zeta potential and polidispersity index. Besides this, the microemulsion-loaded hydrogel (MEH) formulations were evaluated for drug content, pH, rheological properties and in vitro drug release through synthetic membrane and excised pig ear skin in comparison with a conventional hydrogel. The optimised MEH FZ formulations consisting of FZ 2%, Transcutol P 11.5% and 11%, respectively, as oil phase, Lansurf SML 20-propyleneglycol 52% and 50%, respectively, as surfactant–cosurfactant (2:1), Carbopol EDT 2020 1.5% as gelling agent and water 34.5% and 37%, respectively, showed highest flux values and high release rate values, and furthermore, they had low surfactant content. The in vitro FZ permeation through synthetic membrane and excised pig ear skin from the studied MEHs was best described by the zero-order and first-order models. Finally, the optimised MEH FZ formulations showed similar or slightly higher antifungal activity as compared to that of conventional hydrogel and Nizoral® cream, respectively. The results suggest the potential use of developed MEHs as vehicles for topical delivery of FZ, encouraging further in vitro and in vivo evaluation.KEY WORDS: fluconazole, in vitro skin permeation, microemulsion, microemulsion-loaded hydrogel, topical