67 research outputs found

    Sutherlandia frutescens: The meeting of science and traditional knowledge

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    Sutherlandia frutescens (L.) R.Br. (syn. Lessertia frutescens (L.) Goldblatt and J.C. Manning) is an indigenous medicinal plant extensively used in South Africa to treat a variety of health conditions. It is a fairly widespread, drought-resistant plant that grows in the Western, Eastern, and Northern Cape provinces and some areas of KwaZulu-Natal, varying in its chemical and genetic makeup across these geographic areas.1 Sutherlandia is widely used as a traditional medicine. Extensive scientific studies are being carried out on the safety, quality, and the efficacy of this medicinal plant to validate the traditional claims, elucidate the bioactive constituents, and conduct clinical trials. This has resulted in a unique situation in South Africa’s history, where traditional knowledge and science intersect to provide insight into this popular plant. This photoessay attempts to illustrate the interlinkage of science with the indigenous knowledge of traditional healers, the local knowledge of people who care for the sick, product development, and innovation agenda of the country as it relates to this plant.Web of Scienc

    The context of chemical communication driving a mutualism

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    Recent work suggests that Drosophila and Saccharomyces yeasts may establish a mutualistic association, and that this is driven by chemical communication. While individual volatiles have been implicated in the attraction of D. melanogaster, the semiochemicals affecting the behavior of the sibling species D. simulans are less well characterised. Here, we comprehensively scrutinize a broad range of volatiles produced by attractive and repulsive yeasts to experimentally evaluate the chemical nature of communication between these species. When grown in liquid or on agar-solidified grape juice, attraction to S. cerevisiae was primarily driven by 3-methylbutyl acetate (isoamyl acetate) and repulsion by acetic acid, a known attractant to D. melanogaster (also known as vinegar fly). Using T-maze choice tests and synthetic compounds we show that these responses were strongly influenced by compound concentration. Moreover, the behavioral response is further impacted by the chemical context of the environment. Thus, chemical communication between yeasts and flies is complex, and is not simply driven by the presence of single volatiles, but modulated by compound interactions. The ecological context of chemical communication needs to be taken into consideration when testing for ecologically realistic responses

    Quantifying variation in the ability of yeasts to attract Drosophila melanogaster

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    Yeasts that invade and colonise fruit significantly enhance the volatile chemical diversity of this ecosystem. These modified bouquets are thought to be more attractive to Drosophila flies than the fruit alone, but the variance of attraction in natural yeast populations is uncharacterised. Here we investigate how a range of yeast isolates affect the attraction of female D. melanogaster to fruit in a simple two choice assay comparing yeast to sterile fruit. Of the 43 yeast isolates examined, 33 were attractive and seven repellent to the flies. The results of isolate-versus-isolate comparisons provided the same relative rankings. Attractiveness varied significantly by yeast, with the strongly fermenting Saccharomyces species generally being more attractive than the mostly respiring non-Saccharomyces species (P = 0.0035). Overall the habitat (fruit or other) from which the isolates were directly sampled did not explain attraction (P = 0.2352). However, yeasts isolated from fruit associated niches were more attractive than those from non-fruit associated niches (P = 0.0188) regardless of taxonomic positioning. These data suggest that while attractiveness is primarily correlated with phylogenetic status, the ability to attract Drosophila is a labile trait among yeasts that is potentially associated with those inhabiting fruit ecosystems. Preliminary analysis of the volatiles emitted by four yeast isolates in grape juice show the presence/absence of ethanol and acetic acid were not likely explanations for the observed variation in attraction. These data demonstrate variation among yeasts for their ability to attract Drosophila in a pattern that is consistent with the hypothesis that certain yeasts are manipulating fruit odours to mediate interactions with their Drosophila dispersal agent. © 2013 Palanca et al

    MICROWAVE FOURIER TRANSFORM SPECTRA OF SMALL MOLECULES PRODUCED IN ELECTRIC DISCHARGES

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    * Present address: Laboratorium f\""{u}r Physikalische Chemie, Eidgen\""{o}ssische Technische Hochschule, 8092 Z\""{u}rich, Switzerland. †\daggerPresent address: Faculty of Liberal Arts, Shizuoka University, Shizuoka 422, Japan.Author Institution: Department of Chemistry, University of British ColumbiaA pulsed electric discharge apparatus has been designed and incorporated with a cavity microwave Fourier transfrom spectrometer. Samples have been prepared both by reaction with metal from the electrodes and by decomposition of suitable precursors. Example metal compounds are AgCl and AgF; for the former the very high resolution of the instrument has besn used to improve greatly the precision of the 35Cl^{35}Cl quadrupole coupling constant. Examples of the latter have been the semi-stable molecules SiF2SiF_{2} and FCCCN. For SiF2SiF_{2} the 19F^{19}F magnetic hyperfine structure has been resolved, and has produced both spin-spin and spin-rotation coupling constants. For FCCCN we have made the first measurements of the 14N^{14}N quadrupole coupling constant

    The growth and carcass and meat characteristics of pigs raised in a free-range or conventional housing system

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    CITATION: Hoffman, L. C. et al. 2003. The growth and carcass and meat characteristics of pigs raised in a free-range or conventional housing system. South African Journal of Animal Science, 33(3):166-175.The original publication is available at http://www.sasas.co.zaThe growth performance and the carcass and physical and chemical characteristics of the meat of 24 Landrace X Large White pigs were compared when reared under a free-range or a conventional housing system. The free-range pigs had lower feed intakes and slower growth rates than the conventionally housed pigs. The free-range pigs also had a lower P2 fat depth and therefore yielded a carcass with a higher percentage lean meat. Housing systems had no effect on the weight distribution of the commercial cuts (as a percentage of cold carcass weight). The meat from the free-range pigs was slightly more reddish in colour, but apart from that housing systems had no effect on the water-holding capacity (WHC) of the meat, its initial pH (PH 45) or its final pH (pH24). The meat from the free-range pigs had the same shear force (WBS) values as those of the conventionally housed pigs. Housing systems had an influence on the fatty acid composition. Stearic acid (C18:0) was significantly lower in the meat of the free-range pigs than that of the conventionally housed pigs while linoleic acid (C18:2n-6) and polyunsaturated fatty acid (PUFA) concentrations were significantly higher. However, the moisture, fat, protein and ash contents as well as the mineral composition in the meat were unaffected by housing systems. It could be concluded that pigs raised in a conventional housing system produced meat with similar quality characteristics to that of pigs raised in a free-range housing system.ArticlePublisher's versio

    The growth and carcass and meat characteristics of pigs raised in a free-range or conventional housing system

    No full text
    The growth performance and the carcass and physical and chemical characteristics of the meat of 24 Landrace X Large White pigs were compared when reared under a free-range or a conventional housing system. The free-range pigs had lower feed intakes and slower growth rates than the conventionally housed pigs. The free-range pigs also had a lower P fat depth and therefore yielded a carcass with a higher percentage lean meat. Housing systems had no effect on the weight distribution of the commercial cuts (as a percentage of cold carcass weight). The meat from the free-range pigs was slightly more reddish in colour, but apart from that housing systems had no effect on the water-holding capacity (WHC) of the meat, its initial pH (PH ) or its final pH (pH). The meat from the free-range pigs had the same shear force (WBS) values as those of the conventionally housed pigs. Housing systems had an influence on the fatty acid composition. Stearic acid (C18:0) was significantly lower in the meat of the free-range pigs than that of the conventionally housed pigs while linoleic acid (C18:2n-6) and polyunsaturated fatty acid (PUFA) concentrations were significantly higher. However, the moisture, fat, protein and ash contents as well as the mineral composition in the meat were unaffected by housing systems. It could be concluded that pigs raised in a conventional housing system produced meat with similar quality characteristics to that of pigs raised in a free-range housing system
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