Three-dimensional correlation of steric and electronic free energy relationships guides asymmetric propargylation

Chemical reaction outcomes are often rationalized on the basis of independent analyses of steric and electronic effects. We applied three-dimensional free energy relationships correlating steric and electronic effects to design and optimize a ligand class for the enantioselective Nozaki-Hiyama-Kishi propargylation of ketones. The resultant mathematical model describing the steric and electronic parameter relationship is highly reliant on the synergistic interactions of these two effects.     

Targeting of diacylglycerol degradation to M1 muscarinic receptors by beta-arrestins

Seven-transmembrane receptor (7TMR) signaling is transduced by second messengers such as diacylglycerol (DAG) generated in response to the heterotrimeric guanine nucleotide-binding protein Gq and is terminated by receptor desensitization and degradation of the second messengers. We show that beta-arrestins coordinate both processes for the Gq-coupled M1 muscarinic receptor. beta-Arrestins physically interact with diacylglycerol kinases (DGKs), enzymes that degrade DAG. Moreover, beta-arrestins are essential for conversion of DAG to phosphatidic acid after agonist stimulation, and this activity requires recruitment of the beta-arrestin-DGK complex to activated 7TMRs. The dual function of beta-arrestins, limiting production of diacylglycerol (by receptor desensitization) while enhancing its rate of degradation, is analogous to their ability to recruit adenosine 3',5'-monophosphate phosphodiesterases to Gs-coupled beta2-adrenergic receptors. Thus, beta-arrestins can serve similar regulatory functions for disparate classes of 7TMRs through structurally dissimilar enzymes that degrade chemically distinct second messengers.     

Superluminal and slow light propagation in a room-temperature solid

We have observed both superluminal and ultraslow light propagation in an alexandrite crystal at room temperature. Group velocities as slow as 91 meters per second to as fast as -800 meters per second were measured and attributed to the influence of coherent population oscillations involving chromium ions in either mirror or inversion sites within the crystal lattice. Namely, ions in mirror sites are inversely saturable and cause superluminal light propagation, whereas ions in inversion sites experience conventional saturable absorption and produce slow light. This technique for producing large group indices is considerably easier than the existing methods to implement and is therefore suitable for diverse applications.     

Improving ‘Bing’ sweet cherry fruit quality with plant growth regulators

Final fruit diameter is the prime determinant of sweet cherry fruit value. Previous research has shown that mesocarp cell size accounts predominantly for variability in final fruit size, within a genotype. Our research program evaluated the potential to improve sweet cherry fruit size/weight with growth regulators to affect cell division and/or cell expansion stages. In the current study we screened 8 plant growth regulators (PGRs), including cytokinins, gibberellins, and auxins, and their combinations for their ability to increase ‘Bing’ fruit weight. Each PGR was mixed in lanolin paste and applied to fruit pedicels at 9 or 30 days after full bloom (DAFB), to coincide with estimated peak in cell division and cell expansion activity, respectively. Several cytokinins applied 30 DAFB improved fruit weight significantly (ca. +15%) with N-(2-Chloro-4-pyridyl)-N′-phenylurea (CPPU) and 6-(3-hydroxybenzylamino) purine (mt-Topolin) at 100 mg l⁻¹ being the most effective. Gibberellins, applied alone, improved fruit size and delayed fruit maturation and exocarp coloration. GA₃ at 200 mg l⁻¹ applied at 9 DAFB was the most effective and improved final fruit weight by 15%. Fifty-six percent of the fruit from this treatment were ≥9 g compared to 15% of similar weight fruit from untreated limbs. Both GA₃ and GA_4/7 treatments applied 9 DAFB increased fruit radial expansion. 4-Chlorophenoxyacetic acid, a synthetic auxin, also stimulated higher fruit growth rates at stage I and stage II, and fruit color development, but did not improve final fruit size.     

Habitat and food choice of the critically endangered cao vit gibbon (Nomascus nasutus) in China: Implications for conservation

Knowledge of habitat and feeding ecology is essential for developing an effective conservation management plan for threatened primates. Despite having been rediscovered nearly a decade ago, very little is known of the critically endangered cao vit gibbon (Nomascus nasutus) or its habitat. We analysed forest cover, made direct observations and conducted interviews of local elders to better understand forest changes and to determine the forest characters and species important to the survival of the gibbon. Interviews indicated human-induced forest resource exploitation focused on species-specific and larger trees most easily accessed. Gibbon forest habitat comprised four primary forest types. The mean canopy height over the whole site was 10.52 m. Gibbons consumed 81, or nearly half of the tree and liana species recorded in the site; however, only 19 species provide 77.8% of the diet. Six of the 19 food species were logged for different reasons throughout the history of the site. We conclude that effective conservation management of primates with highly limited distributions, focused dietary needs, and in degraded ecosystems will require active forest restoration, such as planting important food species in degraded sites.     

Turning back the tide of American mink invasion at an unprecedented scale through community participation and adaptive management

Successful eradications of harmful invasive species have been mostly confined to islands while control programs in mainland areas remain small, uncoordinated and vulnerable to recolonisation. To allow the recovery of threatened native species, innovative management strategies are required to remove invasives from large areas. We took an adaptive approach to achieve large scale eradication of invasive American mink in North East Scotland. The project was centred on the Cairngorms National Park (Scotland), with the primary aim of protecting endangered water vole populations. The project was initiated by scientists and supported and implemented through a partnership comprising a government agency, national park authority and local fisheries boards. Capitalising on the convergent interests of a diverse range of local stakeholders, we created a coordinated coalition of trained volunteers to detect and trap mink. Starting in montane headwaters, we systematically moved down river catchments, deploying mink rafts, an effective detection and trapping platform. Volunteers took increasing responsibility for raft monitoring and mink trapping as the project progressed. Within 3 years, the project removed 376 mink from 10570 km² with the involvement of 186 volunteers. Capture rate within sub-catchments increased with greater connectivity to mink in other sub-catchments and with proximity to the coast where there is more productive habitat. The main factor underpinning the success of this project was functional volunteer participation. The project is a reason for optimism that the tide of invasion can be rolled back on a large scale where the convergent interest of local communities can be harnessed.     

A Mark–Recapture Technique for Monitoring Feral Swine Populations

Techniques to monitor populations of feral swine (Sus scrofa) relative to damage control activities are needed on rangelands. Our objectives were to describe and assess a mark–recapture technique using tetracycline hydrochloride (TH) for monitoring feral swine populations. We established bait stations at study sites in southern and central Texas. During 1 d, we replaced normal soured corn bait with bait containing TH and counted the number of feral swine that consumed bait with observers. We conducted feral swine removal using box-style traps and helicopters, at which time we collected teeth for TH analysis. In southern Texas, we estimated population reduction to be 43%. In central Texas, we estimated population reduction of 31%. Our mark–recapture population monitoring technique would complement programs to manage feral swine populations and damage through lethal control.