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The recent increase in the incidence of tuberculosis (TB) with the emergence of multidrug-resistant (MDR) cases has lead to the search for new TB-drugs. Mycobacterium tuberculosis is a complex, resilient organism, and it is important to note that new drugs are required which can reduce TB’s six month treatment time and can be effective against drug-resistant strains of mycobacteria. Plants contain numerous biological active compounds, many of which have been shown to have antimicrobial activity. The search for biologically active extracts based on traditional use of plants is relevant due to the appearance of microbial resistance to many antibiotics and the occurrence of fatal opportunistic infections. Ethanol extracts of seven selected ethnobotanically South African medicinal plants (Artemisia afra, Dodonaea angustifolia, Drosera capensis, Galenia africana, Prunus africana, Syzygium cordatum and Ziziphus mucronata) were investigated for their antimycobacterial activity against two Mycobacterium species. The minimum inhibitory concentration (MIC) of ethanol extracts of A. afra, Dodonaea angustifolia, Drosera capensis and G. africana ranged from 0.781 to 6.25 mg/mL against a non-pathogenic strain of mycobacteria, ‘M. smegmatis’. G. africana showed the best activity, exhibiting an MIC of 0.781 mg/mL and a minimum bactericidal concentration (MBC) of 1.563 mg/mL against M. smegmatis. A drug sensitive strain of M. tuberculosis was found to be susceptible to the ethanol extracts of Dodonaea angustifolia and G. africana. (MICs 5.0 and 1.2 mg/mL respectively) when using the rapid radiometric-BACTEC method. The phytochemical analysis of G. africana led to the isolation and identification of three known compounds namely; (2S)-5,7,2'-trihydroxyflavanone, (E)-3,2',4'-trihydroxychalcone (not reported from natural sources) and (E)-2',4'-dihydroxychalcone. A novel chalcone ‘(E)-3,2',4'-trihydroxy-3'-methoxychalcone’ was also isolated from the ethanol extract of G. africana. Isolation of (2S)-5,7,2'-trihydroxyflavanone, (E)-3,2',4'-trihydroxychalcone and E)-3,2',4'-trihydroxy-3'-methoxychalcone was reported for the first time from this plant. The MIC of novel compound against M. tuberculosis was found to be 50.0 µg/mL whereas (2S)-5,7,2'-trihydroxyflavanone and (E)-3,2',4'-trihydroxychalcone exhibited an MIC of 100.0 µg/mL. During synergistic studies using (2S)-5,7,2'-trihydroxyflavanone and (E)-2',4'-dihydroxychalcone with the antituberculosis drug INH, it was found that the MICs of INH and the compounds were reduced sixteen and eight-fold respectively, resulting in a Fractional Inhibitory Concentration (FIC) of 0.1250 and 0.1875 respectively. The synergistic effect of two isolated compounds (2S)-5,7,2'-trihydroxyflavanone and (E)-2',4'-dihydroxychalcone) in in vitro studies also showed synergistic action, reducing their original MICs four-fold resulting in a FIC of 0.5. Since (2S)-5,7,2'-trihydroxyflavanone and (E)-2',4'-dihydroxychalcone from G. africana showed synergistic activity with INH, it is speculated that the compounds might have similar mechanism as that of INH. However, mechanistic studies on these compounds should be done in order to get an indication of the ‘flavonoids and chalcones’ interferences on mycolic acid synthesis, membrane synthesis and enzyme inhibition. Our investigation on the NADPH oxidase activity of (2S)-5,7,2'-trihydroxyflavanone with Mtr, found that this compound failed to exhibit any NADPH oxidase activity at 800 µM concentrations. Mtr is evidently not the target for the antimycobacterial activity of (2S)-5,7,2'-trihydroxyflavanone. Fifty percent inhibitory concentration of the ethanol extract of G. africana, and the two purified compounds, (2S)-5,7,2'-trihydroxyflavanone and (E)-2',4'-dihydroxychalcone were found to be 120.0; 110.3 and 80.2 µg/mL respectively against the U937 cells. The MIC of the ethanol extract of G. africana in U937 macrophages infected with M. tuberculosis was found to be 50.0 µg/mL indicating the extract’s intracellular antimycobacterial activity in real physiological conditions. The two purified compounds also showed good intracellular antimycobacterial activity. The MICs of (2S)-5,7,2'-trihydroxyflavanone and (E)-2',4'-dihydroxychalcone were found to be 100 and 50 µg/mL respectively. This study indicated that the intracellular activity of the ethanol extract is significant in macrophages. The activity might be due to M. tuberculosis being unable to avoid macrophage killing and its survival during phagocytosis, (including inhibition of phagosome-lysosome fusion, inhibition of the acidification of phagosomes, resistance to killing by reactive oxygen intermediates and modification of the lipid composition of the mycobacterial cell membrane, thereby altering its capacity to interact with immune or inflammatory cells). It can be concluded that the traditional use of G. africana for TB has been scientifically validated to some extent. Isolated compounds and the ethanol extract of the plant warrant further investigation for their potential as antimycobacterial agents. Since synergistic activity of purified compounds with existing antituberculosis drug INH, was significant, it will be worthwhile evaluating the efficacy of purified compounds in combination with TB-drugs in pre-clinical studies. / Thesis (PhD)--University of Pretoria, 2009. / Plant Science / unrestricted

Abstract Cordia africana (Boraginaceae) is a tree used in traditional medicine to treat inflammation related conditions and infectious diseases. This study was undertaken with the objectives of establishing the scavenging effect of extracts and fractions of Codia africana on the mediator of inflammation Lipoxygenases (LOX), and some non-biological free radicals such as 2,2-diphenyl-1-picrylhydrazyl (DPPH), the [2, 2-azinobis (3-ethylbenzothiazoline-6-sulfonic acid)] (ABTS) radicals and the Ferric ion reducing antioxidant power (FRAP). Antimicrobial activities, total phenolics/flavonoids and cytotoxicity of extracts of Codia africana were also evaluated. Extracts were obtained by maceration. Anti-inflammatory activity was determined using a LOX-inhibitor screening assay kit according to the manufacturer's instructions. A broth serial micro dilution method was used to determine the minimum inhibitory concentration (MIC) against, Gram-positive and Gram-negative bacteria and Mycobacterium species. The antioxidant activity was determined using free-radical-scavenging assays, and the 3-(4,5- dimethylthiazolyl-2)-2,5- diphenyltetrazolium bromide reduction assay was used for cytotoxicity. Both the extracts of C. africana inhibited LOX enzyme. The most active being the methanol extract of the bark with IC50 value of 55 ± 0.9 μg/ml. Both the extracts of C. africana, had excellent to weak antimicrobial activites (MICs ranging from 32 to 1024 μg/ml) against bacteria. All the extracts had significant (P< 0.05) free-radical scavenging activity (IC50 ranging from 6.79 ± 0.07 to 331.98 ± 0.07 μg/ml). There was a positive correlation between the antioxidant activity and the total flavonoid and total phenolic contents of Cordia africana. The cytotoxicity on Vero cells was low with LC50 of 81.79 ± 13.31 and 99.67 ± 16.10 μg/ml. The results support the use of C. africana leaves in traditional medicine to treat inflammation related conditions and infectious diseases.

A descolonização literária tem sido, de modo geral, o projecto da escrita ficcional pós-colonial. No mundo das letras africanas, Chinua Achebe (Nigéria), Ahmadou Kourouma (Costa do Marfim) e Mia Couto (Moçambique) têm questionado técnicas romanescas, discursos e estratégias dizcursivas ocidentais a partir de uma posição privilegiada entre dois mundos. este estudo pretende demonstrar que as literaturas africanas modernas se afirmaram como entidades autónomas das literaturas ocidentais e, mais especificamente, que um romance africano difere de um romance ocidental tanto a nível da sua dimensão ética e sócio-histórica como das convenções estéticas que o enformam. Com este nosso estudo, pretendemos, por conseguinte, demonstrar que estes autores providenciaram importantes modelos, no âmbito do romance, para uma prática literária africana. Seguindo uma metodologia comparatista, cobrimos um vasto período cronológico bem como diferentes áreas geográfico-literaárias africanas para encontrarmos migrações temáticas, discursivas, estilísticas e retóricas. Assumimos Achebe e as suas obras, Things fall apart (1958), A man of the people (1966) e Anthilis of the Savannah (1987), como elemento comparante, e tomámos as obras de Ahmadou Kourouma, Les soleils des indépendances (1970), e Mia Couto, A varanda do Frangipani (1996) e O último voo do flamingo (2000), como elementos comparados. A dissertação está dividida em três capítulos que abordam os principais vectores por onde passa o processo de descolonização literária nos três autores.(...)

There are local populations of African elephants (Loxodonta africana) which have increased to levels where they are implicated in altering vegetation types. The local reduction of elephant numbers for wildlife management objectives can involve contraception, killing excess animals, or translocation to alternative habitats. The effects these management decisions can have on the physiological stress response of free-ranging African savanna elephants are still not fully understood. We examined the effect of translocation on faecal glucocorticoid metabolite levels of an African elephant family group,which was translocated within the Kruger National Park, South Africa. We found that translocation resulted in a significant increase in faecal glucocorticoid metabolite levels (up to 646 ng/g wet weight) compared to (1) pre-translocation levels in this group, (2) post-translocation levels in this group, and (3) levels measured in undisturbed ‘control’ groups in the area. However, the faecal glucocorticoid metabolite levels had returned to <100 ng/g by the time the translocated animals had navigated their way back to their previous home range, covering 300 km in 23 days.

By 2001, elephants had been translocated (mainly from Kruger National Park) to 58 small, fenced reserves in South Africa. All but two introductions took place since 1989. We document important aspects of the population dynamics of elephants in these reserves using data collected in a survey conducted in 2001. The mean population size was 45 elephants, with an average density of 0.25 elephants/km2. Populations have a female bias with 0.79 males to females. Populations have 19% adult males, and 31% adult females. On average, almost 50% of the population comprises adult and subadult females, indicating an immanent potential for large population growth. Births were not significantly different froma 1:1 sex ratio. When two extreme populations were removed, mean mortality rate was 0.4% per annum.Population growth rates averaged 8.3%,but five reserves had growth rates above 13%, and the highest annual growth rate was 16.5% per annum. Twenty-seven populations already have densities above 0.2 elephants/km2, and eight reserves have densities above 0.4 elephants/km2. Assuming a 12% per annum growth (feasible given the data presented), over half the reserves will have densities above 0.33 elephants/km2 within five years. These results indicate that the translocation of elephants has been successful, with most populations reproducing at a rate far exceeding expectations. This has serious implications for owners and managers, as some form of population control (contraception, removals, culling etc.) needs to be urgently planned for implementation as soon as possible in most, and probably all small reserves.

It has been suggested that African savanna elephants Loxodonta africana produce 31 different call types (Langbauer 2000). Various researchers have described these calls by associating them with specific behavioural contexts. More recently Leong et al. (2003) have attempted to classify elephant call types based on their physical properties. They classified 8 acoustically distinct call types from a population of captive elephants. This study focuses on one of these call types, the rumble, in a wild population of elephants in Kruger National Park, South Africa. A single family group of elephants was followed to record group behaviours and vocalizations from January through August 2001. By measuring the physical properties of 663 rumbles and subjecting these to cluster analysis, we present evidence that shows that rumbles can be categorized by their physical properties and that the resulting rumble types are associated with specific group behaviours. We characterize three types of rumbles that differ significantly by ten acoustic parameters. Two rumble types were associated with the elephant group feeding and resting, while the third was associated with socializing and agitation.

Dissertação (Mestrado) - Universidade Federal de Santa Catarina, Centro de Comunicação e Expressão. / Made available in DSpace on 2012-10-16T08:55:18Z (GMT). No. of bitstreams: 0Bitstream added on 2016-01-08T20:10:54Z : No. of bitstreams: 1 147328.pdf: 5262899 bytes, checksum: cf85d57c116efec8cbcbe226645216d6 (MD5)

Programa de Pós-Graduação em Letras. Departamento de Letras, Instituto de Ciências Humanas e Sociais, Universidade Federal de Ouro Preto. / Submitted by Marise Leite (marise_mg@yahoo.com.br) on 2016-03-28T13:55:13Z No. of bitstreams: 1 DISSERTAÇÃO_NadaPassaNada.pdf: 998976 bytes, checksum: 2e3e7785167a3fad8663da4fde82f8b7 (MD5) / Approved for entry into archive by Oliveira Flávia (flavia@sisbin.ufop.br) on 2016-04-11T15:21:34Z (GMT) No. of bitstreams: 1 DISSERTAÇÃO_NadaPassaNada.pdf: 998976 bytes, checksum: 2e3e7785167a3fad8663da4fde82f8b7 (MD5) / Made available in DSpace on 2016-04-12T17:40:36Z (GMT). No. of bitstreams: 1 DISSERTAÇÃO_NadaPassaNada.pdf: 998976 bytes, checksum: 2e3e7785167a3fad8663da4fde82f8b7 (MD5) Previous issue date: 2014 / Nesta dissertação analisamos o romance O vendedor de passados, do escritor angolano José Eduardo Agualusa (2004), uma narrativa que une a história do protagonista Félix Ventura, um negro albino, mercador de memórias, e do narrador Eulálio, uma osga em sua terceira encarnação, à de um país pós-colonizado com uma sociedade emergente, ávida por ancestrais renomados. A partir da ligação entre ficção e história, a historiografia angolana surge como um dos motes da obra, sob o viés ficcional, recontando fatos e ao mesmo tempo criando outros. Neste sentido, O vendedor de passados é lido como metaficção historiográfica, termo utilizado para designar narrativas ficcionais que se apropriam da realidade histórica na construção do enredo. Percorrendo também os campos da formação identitária, a partir da leitura dos processos históricos pelos quais passou Angola, a análise transita pelos caminhos dos estudos culturais e da topoanálise na abordagem do espaço romanesco. Com o objetivo de verificar o modo como ocorre a (re)invenção da memória no romance, lançamos mão de conceitos que contemplam diversos vieses dos estudos da memória, como o da memória coletiva e da memória cultural, enquanto o conceito freudiano de duplo foi o principal apoio teórico na análise da constituição dos personagens do romance. ______________________________________________________________________________________ / ABSTRACT: This Master thesis investigate the novel O vendedor de passados, written by the Angolan author José Eduardo Agualusa (2004). This narrative unites the story of the protagonist Félix Ventura, an albino African that sells memories, and the story of the narrator Eulálio, a gecko in its third incarnation, to the story of a post-colonized country with an emerging society eager for renowned ancestors. From the interrelation between fiction and history, the Angolan historiography emerges as a theme, following a fictional orientation, retelling facts and at the same time creating new ones. In this sense, O vendedor de passados is read as a historiographical metafiction, term used to indicate fictional narratives that appropriates historical reality for the plot construction. This work covers the fields of construction of identity, based on the reading of historical processes whereby Angola has been through, the analyses encompasses the cultural studies and the topoanalysis approach when exploring the novelistic space. Aiming to verify the way that the (re)invention of memory occurs in the novel, concepts related to memory studies from different perspectives have been used, such as collective memory and cultural memory, while the Freudian concept of double was the main theoretical basis when analyzing the constitution of the novel’s characters.

Philosophiae Doctor - PhD / Over the years, microorganisms have become resistant to commonly used antimicrobial agents leading to multidrug resistance. This is believed to occur even with new classes of therapeutic agents thus creating a challenge on the global healthcare system. The study of medicinal plants allows for their possible use as alternative therapeutic agents. Galenia africana (G. africana) is a South African medicinal plant with numerous health benefits. The purpose of this study was to evaluate the potential antimicrobial, antifungal and anticancer properties of the ethanolic extract of G. africana. Prior to evaluating these properties, in vitro and in vivo acute toxicity studies were conducted to assess the toxicity profile of G. africana. The toxicity profile of the G. africana extract was evaluated using acute toxicity studies conducted in animal and reconstituted human epidermis skin models. The results of the acute oral and dermal toxicity studies revealed that the median lethal dosage (LD50) for G. africana extract in Sprague-Dawley rats was considered to exceed 2000 mg/kg. In the dermal sensitization study, the stimulation index (SI) values for the mice treated with the G. africana extract at concentrations of 25% (50 mg/ml), 50% (100 mg/ml), and 100% (200 mg/ml), when compared to the control group, were 1.3, 0.9 and 1.3, respectively which did not result in an SI value of ? 3 in any group. Hence, it did not elicit a hypersensitivity response. In the irritation test, the G. africana (concentrate) and G. africana (in-use dilution) extracts were non-irritant on the reconstituted human epidermis.