Using DNA Metabarcoding to Identify the Floral Composition of Honey: A New Tool for Investigating Honey Bee Foraging Preferences

Identifying the floral composition of honey provides a method for investigating the plants that honey bees visit. We compared melissopalynology, where pollen grains retrieved from honey are identified morphologically, with a DNA metabarcoding approach using the rbcL DNA barcode marker and 454-pyrosequencing. We compared nine honeys supplied by beekeepers in the UK. DNA metabarcoding and melissopalynology were able to detect the most abundant floral components of honey. There was 92% correspondence for the plant taxa that had an abundance of over 20%. However, the level of similarity when all taxa were compared was lower, ranging from 22–45%, and there was little correspondence between the relative abundance of taxa found using the two techniques. DNA metabarcoding provided much greater repeatability, with a 64% taxa match compared to 28% with melissopalynology. DNA metabarcoding has the advantage over melissopalynology in that it does not require a high level of taxonomic expertise, a greater sample size can be screened and it provides greater resolution for some plant families. However, it does not provide a quantitative approach and pollen present in low levels are less likely to be detected. We investigated the plants that were frequently used by honey bees by examining the results obtained from both techniques. Plants with a broad taxonomic range were detected, covering 46 families and 25 orders, but a relatively small number of plants were consistently seen across multiple honey samples. Frequently found herbaceous species were Rubus fruticosus, Filipendula ulmaria, Taraxacum officinale, Trifolium spp., Brassica spp. and the non-native, invasive, Impatiens glandulifera. Tree pollen was frequently seen belonging to Castanea sativa, Crataegus monogyna and species of Malus, Salix and Quercus. We conclude that although honey bees are considered to be supergeneralists in their foraging choices, there are certain key species or plant groups that are particularly important in the honey bees environment. The reasons for this require further investigation in order to better understand honey bee nutritional requirements. DNA metabarcoding can be easily and widely used to investigate floral visitation in honey bees and can be adapted for use with other insects. It provides a starting point for investigating how we can better provide for the insects that we rely upon for pollination.     

Biotic and Human Vulnerability to Projected Changes in Ocean Biogeochemistry over the 21st Century

Ongoing greenhouse gas emissions can modify climate processes and induce shifts in ocean temperature, pH, oxygen concentration, and productivity, which in turn could alter biological and social systems. Here, we provide a synoptic global assessment of the simultaneous changes in future ocean biogeochemical variables over marine biota and their broader implications for people. We analyzed modern Earth System Models forced by greenhouse gas concentration pathways until 2100 and showed that the entire world''s ocean surface will be simultaneously impacted by varying intensities of ocean warming, acidification, oxygen depletion, or shortfalls in productivity. In contrast, only a small fraction of the world''s ocean surface, mostly in polar regions, will experience increased oxygenation and productivity, while almost nowhere will there be ocean cooling or pH elevation. We compiled the global distribution of 32 marine habitats and biodiversity hotspots and found that they would all experience simultaneous exposure to changes in multiple biogeochemical variables. This superposition highlights the high risk for synergistic ecosystem responses, the suite of physiological adaptations needed to cope with future climate change, and the potential for reorganization of global biodiversity patterns. If co-occurring biogeochemical changes influence the delivery of ocean goods and services, then they could also have a considerable effect on human welfare. Approximately 470 to 870 million of the poorest people in the world rely heavily on the ocean for food, jobs, and revenues and live in countries that will be most affected by simultaneous changes in ocean biogeochemistry. These results highlight the high risk of degradation of marine ecosystems and associated human hardship expected in a future following current trends in anthropogenic greenhouse gas emissions.     

Systematics and biogeography of Indo-Pacific ground-doves

Ground-doves represent an insular bird radiation distributed across the Indo-Pacific. The radiation comprises sixteen extant species, two species believed to be extinct and six species known to be extinct. In the present study, we present a molecular phylogeny for all sixteen extant species, based on two mitochondrial markers. We demonstrate that the Gallicolumba as currently circumscribed is not monophyletic and recommend reinstalling the name Alopecoenas for a monophyletic radiation comprising ten extant species, distributed in New Guinea, the Lesser Sundas and Oceania. Gallicolumba remains the name for six species confined to New Guinea the Philippines and Sulawesi. Although our phylogenetic analyses fail to support a single origin for the remaining Gallicolumba species, we suspect that the addition of nuclear sequence data may alter this result. Because a number of ground-dove taxa have gone extinct, it is difficult to assess biogeographical patterns. However, the Alopecoenas clade has clearly colonized many remote oceanic islands rather recently, with several significant water crossings. The Gallicolumba radiation(s), on the other hand, is significantly older and it is possible that diversification within that group may in part have been shaped by plate tectonics and corresponding re-arrangements of land masses within the Philippine and Sulawesi region.     

An oral developmental neurotoxicity study of decabromodiphenyl ether (DecaBDE) in rats

BACKGROUND: Decabromodiphenyl ether (DecaBDE; CASRN 1163‐19‐5) is a flame retardant used in a variety of manufactured products. A single oral dose of 20.1 mg/kg administered to mice on postnatal day 3 has been reported to alter motor activity at 2, 4, and 6 months of age. METHODS: To further evaluate these results, a developmental neurotoxicity study was conducted in the most commonly used species for studies of this type, the rat, according to international validated testing guidelines and Good Laboratory Practice Standards. DecaBDE was administered orally via gavage in corn oil to dams from gestation day 6 to weaning at doses of 0, 1, 10, 100, or 1,000 mg/kg/day. Standard measures of growth, development, and neurological endpoints were evaluated in the offspring. Motor activity was assessed at 2 months of age. Additional motor activity assessments were conducted at 4 and 6 months of age. Neuropathology and morphometry evaluations of the offspring were performed at weaning and adulthood. RESULTS: No treatment‐related neurobehavioral changes were observed in detailed clinical observations, startle response, or learning and memory tests. No test substance‐related changes were noted in motor activity assessments performed at 2, 4, or 6 months of age. Finally, no treatment‐related neuropathological or morphometric alterations were found. CONCLUSIONS: Under the conditions of this study, the no‐observed‐adverse‐effect level for developmental neurotoxicity of DecaBDE was 1,000 mg/kg/day, the highest dose tested. Birth Defects Res (Part B) 92:17–35, 2011.© 2011 Wiley‐Liss, Inc.     

Effect of the inositol polyphosphate InsP(6) on DNA-PK-dependent phosphorylation

Inositol hexakisphosphate (InsP(6)) is a member of the inositol polyphosphate group that participates in numerous intracellular signaling pathways. Cheung and colleagues previously reported that InsP(6) stimulated double-strand break repair by nonhomologous end joining (NHEJ) in cell-free extracts and that InsP(6) binding by the Ku70/80 subunit of the DNA-dependent protein kinase (DNA-PK) was required for stimulation of NHEJ in vitro. This report describes InsP(6)-dependent phosphorylation of two NHEJ factors, XRCC4 and XLF, in partially purified human cell extracts. XRCC4 and XLF are known substrates for DNA-PK, which does not require InsP(6) for protein kinase activity. Consistent with a role for DNA-PK in these reactions, InsP(6)-dependent phosphorylation of XRCC4 and XLF was DNA dependent and not observed in the presence of DNA-PK inhibitors. Depletion of the Ku70/80 DNA-, InsP(6)-binding subunit of DNA-PK resulted in loss of InsP(6)-dependent phosphorylation and showed a requirement for Ku70/80 in these reactions. Complementation of Ku70/80-depleted reactions with recombinant wild-type Ku70/80 restored InsP(6)-dependent phosphorylation of XRCC4 and XLF. In contrast, addition of a Ku70/80 mutant with reduced InsP(6) binding failed to restore InsP(6)-dependent phosphorylation. While additional protein kinases may participate in InsP(6)-dependent phosphorylation of XRCC4 and XLF, data presented here describe a clear requirement for DNA-PK in these phosphorylation events. Furthermore, these data suggest that binding of the inositol polyphosphate InsP(6) by Ku70/80 may modulate the substrate specificity of the phosphoinositide-3-kinase-related protein kinase DNA-PK.     

Opium poppy capsule growth and alkaloid production is constrained by shade during early floral development

Morphinan alkaloids accumulate in the capsules of Papaver somniferum L. (opium poppy) most likely as defence against herbivory. Thus, capsule size is an important component of alkaloid yield. Shade during early cell division-dominated growth of reproductive structures generally reduces final fruit size more than shade during later cell expansion-dominated growth. The current study aimed to determine whether this response is found in opium poppy and the subsequent impact on alkaloid yield, composition and seed production. First the timing of key reproductive developmental events was resolved relative to macromorphological traits. Plants were then shaded during either (a) floral initiation, (b) early floral development or (c) capsule expansion before being harvested at maturation. Shade during floral initiation dramatically reduced final capsule size, alkaloid yield and seed number, and increased the concentration of precursor compounds relative to morphine, despite plants later returning to full sun. Shade during later capsule growth enhanced capsule size and alkaloid yield but had little effect on alkaloid composition or seed number. Thus, early developmental processes, including morphine biosynthesis, appear to have a relatively greater demand for carbohydrates compared with later processes. Crop management practices and environmental factors that limit carbohydrate availability during early development are thus predicted to have significant negative impacts on alkaloid production and reproductive success.     

Anadromy and marine habitat use of Lake trout (Salvelinus namaycush) from the central Canadian Arctic

Anadromy was documented in 16 lake trout, Salvelinus namaycush, from Canada's central Arctic using capture data and otolith microchemistry. For the first time, estuarine/marine habitat use was described for five individuals using acoustic telemetry. Age-at-first-migration to sea was variable (10–39 years) among individuals and most S. namaycush undertook multiple anadromous migrations within their lifetime. Telemetry data suggested that S. namaycush do not travel far into marine habitats and prefer surface waters (<2 m). These results further our collective understanding of the marine ecology of Arctic S. namaycush.     

Mitigation of cardiovascular toxicity in a series of CSF-1R inhibitors,and the identification of AZD7507

The potent and selective 3-amido-4-anilinoquinoline CSF-1R inhibitor AZ683 suffered from cardiovascular liabilities, which were linked to the off-target activities of the compound and ion channel activity in particular. Less basic and less lipophilic examples from both the quinoline and cinnoline series demonstrated cleaner secondary pharmacology profiles. Cinnoline 31 retained the required potency and oral PK profile, and was progressed through the safety screening cascade to be nominated into development as AZD7507.