66 research outputs found
A taxonomic study of the genus Lotononis (DC.) Eckl. & Zeyh. (Fabzceae, Crotalarieae)
The approach and methods used in a taxonomic study of the genus Lotononis (DC.) Eckl. & Zeyh. and related genera of the tribe Crotalarieae (Benth.) Hutch. are briefly introduced in Part 1. Morphological, cytological and chemical data was analyzed by cladistic methods to provide a sound basis for the generic delimitation of Lotononis and to formulate a natural infrageneric classification. The generic limits of Lotononis and its relationships with 14 other genera of the Crotalarieae are discussed in Part 2. Detailed morphological studies by Polhill (1976) has shown the widespread occurrence of convergence and conflicting character information in the tribe. Only a few of the genera are monothetic taxa and very few characters are available for cladistic analyses. This is not so much due to a lack of data but rather to ambiguity as to how morphological characters should be interpreted. It was therefore decided to concentrate on a study of alkaloids to test the predictivity of the present generic delimitations in the Crotalarieae. With the exception of Crotalaria L., virtually nothing was known about the alkaloids of the tribe (Mears & Mabry 1971, Kinghorn & Smolenski 1981). In the tribe Genisteae, alkaloid patterns show a high degree of conformity with evolutionary patterns based on morphological evidence (Polhill 1976) and the value of alkaloids as a generic character in the Leguminosae is well known (Kinghorn & Smolenski 1981). It seemed that more insight into generic relations in the Crotalarieae could be gained by concentrating on a hitherto much neglected field rather than to duplicate the detailed morphological studies of Polhill (1976). It was also clear that meaningful conclusions could be made about generic relationships, because the biogenetic pathways along which quinolizidine and pyrrolizidine alkaloids are formed are rather well known. The survey of major alkaloids (Appendices 1 to 11) indeed led to a much better understanding of the intricate relationships in the Crotalarieae, and made it possible to present a well supported and almost fully resolved cladogram for the tribe as a whole
Alkaloidal variation in Cissampelos capensis (Menispermaceae)
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Doing an ethnobotanical survey in the life sciences classroom
On the basis of an ethnobotanical survey that we conducted on plant use by descendents of the Khoi-San people in the Northern Cape Province in South Africa, we introduce biology teachers to an adapted rapid-appraisal methodology that can be followed in the life sciences classroom. Such a project addresses a number of the content standards in the National Science Education Standards, such as science as a human endeavour, the nature of science, and the history of science. We also shed light on ethical considerations when engaging in an ethnobotanical survey, and address, among other issues, intellectual property rights. Examples are provided of how teachers in the United States can sensitize students to the rich ethnobotanical heritage of their country
Apparent Absorption Efficiencies of Nectar Sugars in the Cape Sugarbird, with a Comparison of Methods
Nectarivore sugar preferences and nectar composition in the Cape Floristic Kingdom (southern Africa) differ from trends reported for analogous systems in America and Europe in that sugarbirds and sunbirds show no aversion to sucrose, which is the dominant nectar sugar in many of their food plants. To elucidate the physiological bases (if any) of nectarivore sugar preferences, we determined apparent sugar absorption efficiencies in a passerine endemic to this region, the Cape sugarbird Promerops cafer. Apparent absorption efficiencies for the three major nectar sugars, sucrose, glucose, and fructose, were extremely high (> 99%), as in other specialized avian nectarivores. Xylose, a pentose sugar recently reported in the nectar of some Proteaceae, was absorbed and/or metabolized inefficiently, with a mean of 47.1% of ingested sugar recovered in cloacal fluid. We did not measure the proportions of xylose that were absorbed and/or metabolized. We also compared three methods of estimating absorption efficiency: (1) measurements of total sugar in cloacal fluid with refractometry, without correction for differences between volumes of ingesta and excreta; (2) the same measurements combined with correction for volume differences; and (3) HPLC analyses quantifying individual sugars in cloacal fluid, with correction for volume differences. Refractometry has been frequently used in previous studies. For all sugars except xylose, method 1 yielded results similar to those obtained with method 2, but the convergence was artifactual, and we do not recommend use of this method. Apparent absorption efficiencies calculated with method 2 underestimated true absorption efficiency, because refractometry measures nonsugar solutes, but this error is biologically significant only when efficiencies are low
A global infrageneric classification system for the genus Crotalaria (Leguminosae) based on molecular and morphological evidence
Crotalaria is a large genus of 702 species with its centre of diversity in tropical Africa and Madagascar and secondary radiations in other parts of the world. The current infrageneric classification system is based on morphological and morphomet- ric studies of the African taxa only and is here re-evaluated using a phylogenetic approach. DNA sequences derived from the nuclear ITS and the plastid matK, psbA-trnH and rbcLa markers were analyzed using parsimony and model-based (Bayesian) approaches. The resultant molecular phylogeny allowed for a new interpretation of diagnostically important morphological characters, including specialisations of the calyx, keel, standard petal and style, which are variously convergent in several unrelated infrageneric groups. Of particular interest is the congruence between the new phylogeny and the distribution of stand- ard petal callosity types. A sectional classification system for the entire genus is proposed for the first time. The new system that is formalised here comprises eleven sections: Amphitrichae, Calycinae, Crotalaria, Geniculatae, Glaucae, Grandiflorae, Hedriocarpae, Incanae, Schizostigma, Borealigeniculatae and Stipulosae. Sectional limits of the Geniculatae, Calycinae and Crotalaria are modified. The subsections Stipulosae, Glaucae and Incanae are raised to sectional level, while some groups previously recognized as subsections are abandoned due to non-monophyly (subsections Chrysocalycinae, Hedriocarpae, Macrostachyae and Tetralobocalyx). Two new sections are recognized, Amphitrichae and Borealigeniculatae.Web of Scienc
Traditional uses of the remarkable root bark hairs of Lannea schweinfurthii var. stuhlmannii (Anacardiaceae) by the Vhavenḓa, South Africa
Lannea schweinfurthii var. stuhlmannii, an African tree ranging from Sudan southwards to South Africa, has its thicker roots covered by an unusual furry layer of hair-like structures originating from the periderm. Wool-like hairs harvested from this layer, known in the vernacular Tshivenḓa as vhulivhadza, is a widely used and traded natural product in Limpopo Province, South Africa. Here we provide a detailed account of the cultural uses of vhulivhadza based on original ethnobotanical surveys among the Vhavenḓa, as well as a review of the literature. Our findings indicate that vhulivhadza is a “magical medicine,” mostly used to induce several forms of forgetfulness, both in humans and in animals. Various uses reported for L. schweinfurthii and L. alata, the latter an East African species with similar root bark hairs, suggest that the custom to use these hairs to induce forgetfulness is confined to southern Africa. The practice of taking traditional medicine to “forget something” or “to make people forget” is quite widespread in southern Africa. We discuss vhulivhadza and a few other plants used locally for this purpose, notably the mysterious sho-|õä plant of the now extinct | Xam culture, Asclepias crispa (Apocynaceae: Asclepiadoideae) and Galium tomentosum (Rubiaceae). The roots of Lannea schweinfurthii and other members of the genus are rich in phytochemicals, with at least some screenings for biological activity suggesting the presence of compounds that may affect the neurological system. In the absence of any comprehensive chemical or pharmaceutical analyses of vhulivhadza itself, the claimed memory-altering activities of this material can tentatively perhaps best be explained by psychological rather than physical (chemical) effects, but a more definite scientific explanation must await further study.The University of Johannesburg and the National Research Foundation of South Africa.http://www.elsevier.com/locate/sajb2020-05-01hj2020Plant Production and Soil Scienc
Reducing the environmental impact of surgery on a global scale: systematic review and co-prioritization with healthcare workers in 132 countries
Abstract
Background
Healthcare cannot achieve net-zero carbon without addressing operating theatres. The aim of this study was to prioritize feasible interventions to reduce the environmental impact of operating theatres.
Methods
This study adopted a four-phase Delphi consensus co-prioritization methodology. In phase 1, a systematic review of published interventions and global consultation of perioperative healthcare professionals were used to longlist interventions. In phase 2, iterative thematic analysis consolidated comparable interventions into a shortlist. In phase 3, the shortlist was co-prioritized based on patient and clinician views on acceptability, feasibility, and safety. In phase 4, ranked lists of interventions were presented by their relevance to high-income countries and low–middle-income countries.
Results
In phase 1, 43 interventions were identified, which had low uptake in practice according to 3042 professionals globally. In phase 2, a shortlist of 15 intervention domains was generated. In phase 3, interventions were deemed acceptable for more than 90 per cent of patients except for reducing general anaesthesia (84 per cent) and re-sterilization of ‘single-use’ consumables (86 per cent). In phase 4, the top three shortlisted interventions for high-income countries were: introducing recycling; reducing use of anaesthetic gases; and appropriate clinical waste processing. In phase 4, the top three shortlisted interventions for low–middle-income countries were: introducing reusable surgical devices; reducing use of consumables; and reducing the use of general anaesthesia.
Conclusion
This is a step toward environmentally sustainable operating environments with actionable interventions applicable to both high– and low–middle–income countries
n Monografiese studie van die genus Virgilia Poir
Opsomming in Engels.Proefskrif (M. Sc.) -- Universiteit van Stellenbosch, 1983.Full text to be digitised and attached to bibliographic record
Observations on the Association between Some Buprestid and Cerambycid Beetles and Black Frankincense Resin Inducement
Samburu resin harvesters in northern Kenya maintain that frankincense resin flow from Boswellia neglecta and Commiphora confusa is induced by insect larval activity. Observations on the insects’ larval behaviour support these claims. During the frankincense harvest, buprestid beetle larvae, identified as a Sphenoptera species, are found under B. neglecta resin, eating the monoterpene-rich inner bark, which apparently stimulates the trees to produce copious amounts of fresh resin. The same behaviour was observed with cerambycid beetle larvae, identified as Neoplocaederus benningseni Kolbe, on C. confusa trees. Remarkably, these insects have developed the capacity to digest the resin-saturated inner bark and overcome the toxic, repellent characteristics of oleo-monoterpenes. The frankincense resin also appears to act as a protective covering during the insects’ larval and pupal stages. Excessive tree damage was not noted from these insect invasions. Even though the tree species are from different genera, the resin produced by both is black, with a very similar aromatic chemical profile. The question thus arises as to whether the larval feeding behaviour of these beetle species has an influence, not only on the physical appearance but also on the chemical composition of the resins
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