Diet of bluegill Lepomis macrochirus in a South African reservoir during winter and summer

Alien fishes are considered a major threat to aquatic biodiversity in South Africa, yet relatively little regional information on their biology and ecology is available for many of these species. Seasonal changes in the diet of the bluegill Lepomis macrochirus in Howieson’s Poort Dam, Grahamstown, were assessed during summer and winter in 2014–2015, using stomach content analysis. In winter, juvenile and adult fish diets were dominated by crustacean zooplankton and insects, respectively. In summer, juvenile fish fed on crustaceans and insects, whereas adults consumed mostly fish eggs, indicating a potential impact by these invasive fish on native fish through oophagy.     

Failed gene conversion leads to extensive end processing and chromosomal rearrangements in fission yeast

Loss of heterozygosity (LOH), a causal event in cancer and human genetic diseases, frequently encompasses multiple genetic loci and whole chromosome arms. However, the mechanisms by which such extensive LOH arises, and how it is suppressed in normal cells is poorly understood. We have developed a genetic system to investigate the mechanisms of DNA double‐strand break (DSB)‐induced extensive LOH, and its suppression, using a non‐essential minichromosome, Ch¹⁶, in fission yeast. We find extensive LOH to arise from a new break‐induced mechanism of isochromosome formation. Our data support a model in which Rqh1 and Exo1‐dependent end processing from an unrepaired DSB leads to removal of the broken chromosome arm and to break‐induced replication of the intact arm from the centromere, a considerable distance from the initial lesion. This process also promotes genome‐wide copy number variation. A genetic screen revealed Rhp51, Rhp55, Rhp57 and the MRN complex to suppress both isochromosome formation and chromosome loss, in accordance with these events resulting from extensive end processing associated with failed homologous recombination repair.     

Fabrication of molecularly imprinted polymer microarray on a chip by mid-infrared laser pulse initiated polymerisation

The possibility to assess several functional polymeric materials in parallel in a microchip format could find a wide range of applications in sensing, combinatorial and high-throughput screening. However several factors, inherent to the nature of material polymerisation have limited such development. We here report an innovative fabrication approach for the elaboration of polymer microarrays bearing polymer dots typically 300 microm in diameter fabricated in situ on a glass cover slip via CO(2) laser pulse initiated polymerisation, as well as initial results on the identification of a suitable monomer composition for the molecular imprinting of dansyl-L-phenylalanine as a proof-of-concept example. A combination of methacrylic acid and 2-vinylpyridine showed the largest affinity to dansyl-L-phenylalanine which agreed with the existing literature and the results were further confirmed by HPLC. Finally, a sensor chip bearing both non-imprinted as well as imprinted polymers was also prepared in order to prove the suitability of this fabrication approach for the elaboration of MIP based sensors. The assay consisted in a simple dip-and-read step and the sensing system was able to discriminate between the l and d enantiomers of dansylphenylalanine with an imprinting factor of 1.6.     

662. PHELYPAEA BOISSIERI

Phelypaea boissieri (Reuter) Stapf, a spectacular root-parasitic plant, is described and illustrated from plants cultivated near Cambridge. The history of the genus Phelypaea is described and a key to the species is provided. Instructions for its cultivation are given.     

Measurement of cardiac synchrony using Approximate Entropy applied to nuclear medicine scans

As cancer therapy becomes more effective, allowing patients to live longer, the long-term morbidity of treatment assumes greater significance. Trastuzumab (Herceptin^®), a monoclonal antibody that targets the epidermal growth factor, has proven efficacy in breast cancer patients but is also known to be cardiotoxic. Left ventricular ejection fraction (LVEF), a measure of cardiac function, is commonly used to evaluate patients receiving trastuzumab by Multiple Gated Acquisition (MUGA) isotope scans. In this paper, we have assessed the utility of previously published ventricular synchrony parameters in patients undergoing trastuzumab therapy. In addition, we apply Approximate Entropy (ApEn) to MUGA images, as a new measure of cardiac dysfunction and have evaluated its utility in the same patients. A significant change in LVEF (p = 0.015) and ApEn (p = 0.020) but not ventricular synchrony measures were observed over the course of treatment in these patients. The results suggest that ApEn provides a useful measure of cardiac function and synchrony.     

A SNX3-dependent retromer pathway mediates retrograde transport of the Wnt sorting receptor Wntless and is required for Wnt secretion

Wnt proteins are lipid-modified glycoproteins that play a central role in development, adult tissue homeostasis and disease. Secretion of Wnt proteins is mediated by the Wnt-binding protein Wntless (Wls), which transports Wnt from the Golgi network to the cell surface for release. It has recently been shown that recycling of Wls through a retromer-dependent endosome-to-Golgi trafficking pathway is required for efficient Wnt secretion, but the mechanism of this retrograde transport pathway is poorly understood. Here, we report that Wls recycling is mediated through a retromer pathway that is independent of the retromer sorting nexins SNX1-SNX2 and SNX5-SNX6. We have found that the unrelated sorting nexin, SNX3, has an evolutionarily conserved function in Wls recycling and Wnt secretion and show that SNX3 interacts directly with the cargo-selective subcomplex of the retromer to sort Wls into a morphologically distinct retrieval pathway. These results demonstrate that SNX3 is part of an alternative retromer pathway that functionally separates the retrograde transport of Wls from other retromer cargo.     

Habitat manipulation to mitigate the impacts of invasive arthropod pests

Exotic invaders are some of the most serious insect pests of agricultural crops around the globe. Increasingly, the structure of landscape and habitat is recognized as having a major influence on both insect pests and their natural enemies. Habitat manipulation that aims at conserving natural enemies can potentially contribute to safer and more effective control of invasive pests. In this paper, we review habitat management experiments, published during the last 10 years, which have aimed to improve biological control of invasive pests. We then discuss during what conditions habitat management to conserve natural enemies is likely to be effective and how the likelihood of success of such methods can be improved. We finally suggest an ecologically driven research agenda for habitat management programmes.     

Normobaric hyperoxic stress in budgerigars: enzymic antioxidants and lipid peroxidation

The effects of acute (3 h), repeated acute (3 exposures each of 3 h) and chronic (72 h) normobaric hyperoxic exposure in budgerigars (Melopsittacus undulatus) were evaluated by monitoring the effects on pulmonary enzymic antioxidants, and indicators of lipid peroxidation. All durations of oxygen exposure resulted in significant respiratory alkalosis and elevated pulmonary and blood glutathione peroxidase concentrations. The concentrations of other pulmonary enzymic antioxidants including glutathione reductase and superoxide dismutase were not significantly altered by oxygen exposure. Pulmonary concentrations of the lipid peroxidation markers malonaldehyde and 4-hydroxyalkenal were not significantly elevated following oxygen exposure. Plasma concentrations of 8-epi isoprostane F(2alpha) were significantly elevated following both acute and repeated acute exposure. The results indicate that in budgerigars, both acute and chronic oxygen exposure can result in significant alteration in respiratory function and increased production of reactive oxygen species.