Chromolaena odorata (L.) King and Robinson is an alien invasive weed to most of the Old World tropical regions of the earth, including South Africa where it is morphologically distinct from most other C. odorata plants examined from both its native and invasive range. It is thought that these morphological differences are related to difficulties encountered in successful establishment of biological control agents on the South African population of C. odorata. It has been postulated that the source population of the South African population will harbour potential biocontrol agents that will be suited to successful establishment on the South African plants. Several morphological, cytological and isozyme studies have been attempted to identify the source population of the South African population, but these have failed to identify the origin of the South African population. In this dissertation two PCR-based methods were attempted, in an investigation into whether the morphological differences and difficulties in establishment of biocontrol agents have a genetic basis. The two techniques attempted were: Inter Simple Sequence Repeat (ISSR) amplification, and DNA sequencing. Results could not be obtained using the ISSR method, and the reason for this was not discovered despite extensive trials. The internal transcribed spacer region and the external transcribed spacer region sequences were obtained from five samples, and compared. It was found that the ETS region gave more phylogenetic signal at the intraspecific level than the ITS region. However, due to difficulties in amplification of the external transcribed spacer region, work here focussed on obtaining Internal Transcribed Spacer sequences for 61 samples. Each of the samples sequenced had a unique ITS sequence, displaying a high level of intraspecific genetic diversity. The degree of this diversity is discussed with reference to the possible influences of polyploidy and concerted evolution on genetic structure. The ITS data indicated that some of the physical traits used to define ‘morphotypes’ of C. odorata were not correlated to genotype. From discussion and comparison of morphological character distributions and the ITS-based phylogeography it is suggested that the geographical origin of the South African population is Greater Antilelan, rather than from the continents of North and South America, which is where the Australasian, West African and Mauritian infestations are suggested to have originated.

Aims: Cancer is the first cause of death in the Peruvian population; searching alternative treatments of medicinal plants constitute a promissory field to find new anticancer drugs. The main objective in this study was to evaluate the phytochemical screening, total phenolic content, antioxidant and cytotoxic activity of ethanol extract of Chromolaena laevigata (C. laevigata) on human tumor cell lines. Study Design: The fresh leaves of C. laevigata were soaked with ethanol followed by phytochemical screening using standard methods. Place and Duration of Study: Laboratory of Applied Chemistry, Faculty of Pharmacy and Biochemistry, Universidad Nacional San Luis Gonzaga de Ica, Ica, Peru; Laboratory “Abraham Vaisberg Wolach”, Universidad Peruana Cayetano Heredia, Lima, Peru. Methodology: Phytochemical screening was assessed by using chemical reactives. Total phenolic content (TPC) was developed using Folin Ciocalteu reactive and the antioxidant activity was determined against DPPH and ABTS radicals by spectrophotometry. The cytotoxic activity was determined on human tumor cell lines followed as: MCF-7, H-460, HT-29, M-14, K-562 and DU-145. Results: Phytochemical study confirmed flavonoids and phenolic compounds in ethanol extract. TPC resulted 45.21 ± 3.5 mg of gallic acid equivalent/g of dried extract. The highest antioxidant extract for DPPH and ABTS radical scavenging tests were IC50 = 11.66 ± 1.0 μg/mL, IC50= 12.45 ± 0.50 μg/mL respectively. Ethanolic extracts (μg/mL) showed a low cytotoxicity on human tumor cell lines (CI50 > 20 μg/mL) for DU-145, HT-29, MCF-7 and M-14. Whereas, for H-460, and K562 tumor cell lines showed high cytotoxicity. Conclusion: In our findings, C. laevigata demonstrated a high antioxidant and total phenolic content. The ethanol extract exhibited better cytotoxic effect compared with 5-FU. Hence, This medicinal plant could be effective to prevent chronical diseases as cancer and oxidative stress disorders.

Biological indicators measure components of the biota and are used to give general information about complex ecosystems in which they occur, playing key roles in conservation planning and management. This study illustrates the impact of habitat change by factors that are extrinsic to the habitats in question and the importance of spider responses in aiding management decisions. The spider responses illustrated existence of environmental change and represent responses of other biota. The conclusions drawn from this study have important management implications for protected areas with grazing herbivores and occurrence of alien invasive plants. Grazed sites showed the highest abundance, diversity and species richness, while ungrazed had the lowest. The implications from this study are that no grazing has negative implications on lower trophic levels, whereas grazing seems to result in favourable conditions for optimal abundance, diversity and species richness. The higher abundance, diversity and species richness associated with grazed sites could result from increased ground cover, greater variation in habitat structure, increased plant diversity and enhanced soil/plant nutrient concentrations. But, ungrazed sites in turn become more monotonous and provide less habitat diversity. However, the characteristic species for each grazing intensity level demonstrates the difficulty in making generalizations for management even for closely related species. The results further opposed the assumption that grazing lawns are a result of overgrazing and thus highly undesirable. This grassland type in comparison to tall bunch grassland displayed the highest spider diversity and species richness. This evidence further supports the conclusion that grazing lawns are steady state communities of their own and not a sub-set of any other grassland type. Therefore, veld management decisions that eradicate grazing lawns are negative for the park as the fauna and flora associated with this grassland type will be lost, leading to cascading effects. Additionally, this study illustrated that habitat modification by invasion of invasive alien plant species has detrimental consequences for the endemic fauna. C. odorata invasion results in a monotonous habitat structure. Consequently, structural heterogeneity is a primary determinant for spider diversity as opposed to abundance of prey, because plant height and architecture drive spider colonization. Therefore, removal of alien invasive weeds results in returning a system to close approximation of its condition prior to disturbance with both structure and function recreated. Assemblage patterns can be selected as endpoints to measure the ecological rehabilitation; thus, the non-significant differences in assemblage patterns of the control versus cleared sites imply that the system is rehabilitating with clearing without further management intervention. This study adds to the limited information on the implications of grazing intensities, grassland types, short and long-term invasion and clearing of an alien invasive plant on spider communities. Copyright / Dissertation (MSc)--University of Pretoria, 2008. / Animal and Wildlife Sciences / unrestricted

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / Asteraceae (=Compositae) is one of the largest families of plants, comprises about 1,600 genera and 23,000 species. The family has a wide distribution in Brazil occurring in different vegetation formations. The Disynaphiinae and Praxelinae subtribes belong to Eupatorieae tribe, which currently has 19 subtribes. The cypselae and its accessory parts (pappus and carpopodium) have great taxonomic value and can be used as diagnostic to differentiate or group species and even genera. The boundaries between some genera are not well defined based on morphological usual features. The study of the morphology of cypselae in Disynaphiinae and Praxelinae will contribute to the characterization and can understanding their infrageneric relations. The aim is to describe the structure of the pericarp of the mature fruit of the representatives of Disynaphiinae and Praxelinae as well as the varieties of Chromolaena squalida, seeking common morphological characteristics distinct to these groups. Thereunto, we used a scanning electron microscopy and light microscopy. The trichomes, pericarp structure, and accessory parts of cypselae proved useful in taxonomic groups revealing a close relationship between species of each of the subtribes. These features were also important to exclude species e. g. Disynaphia praeficta. Our study also supports the varieties of Chromolaena squalida, allowing the correct identification. The phytomelanin was present in all cypselae studied, but their arrangement differs among the subtribes. The correlation between the number of bundles and ribs is not fixed in Praxelinae and ribs were not always associated with vascular bundles. / Asteraceae (= Compositae) é uma das maiores famílias de plantas, compreende cerca de 1.600 gêneros e 23.000 espécies. A família apresenta no Brasil uma ampla distribuição em diferentes formações vegetacionais. As subtribos Disynaphiinae e Praxelinae pertencem à tribo Eupatorieae, que atualmente apresenta 19 subtribos. As cipselas e suas partes acessórias (pápus e carpopódio) possuem grande valor taxonômico e podem ser usados como diagnósticos para diferenciar ou agrupar espécies e até gêneros. Os limites entre alguns gêneros não são bem definidos baseado nas características morfológicas tradicionais.O estudo da morfologia das cipselas em Disynaphiinae e Praxelinae contribuirá para a caracterização e o entendimento das relações infragenéricas nestas subtribos. O objetivou-se, com esta dissertação, descrever a micromorfologia e a estrutura do pericarpo do fruto maduro dos representantes de Disynaphiinae e Praxelinae, bem como das variedades de Chromolaena squalida, buscando características morfológicas comuns e distintas a estes grupos. Para isso, utilizou-se a Microscopia Eletrônica de Varredura e a Microscopia de luz. Nas subtribos Disynaphiinae e Praxelinae, características analisadas como o indumento, a estrutura do pericarpo e partes acessórias das cipselas, mostraram-se úteis na taxonomia dos grupos, revelando a proximidade entre as espécies de cada uma das subtribos, tais características também foram importantes na rejeição de espécies (Disynaphia praeficta). O presente estudo suporta as variedades de Chromolaena squalida, permitindo a correta identificação. A fitomelanina esteve presente em todas as cipselas, porém o arranjo dessa camada difere nas subtribos estudadas. A correlação entre o número de feixes vasculares e a presença de costelas não é fixa em Praxelinae e as costelas não necessariamente estavam associadas com feixes vasculares. / Mestre em Biologia Vegetal

En Afrique de l'Ouest, les sols de savanes humides se caractérisent par des concentrations extrêmement basses de matières organiques, d'azote minéral, de phosphore et de cations basiques, ce qui limite la production primaire. Ce travail a analysé comment des changements particuliers dans les utilisations des terres peuvent influencer le fonctionnement et la fertilité des sols, pour in fine soutenir la production des agroécosystèmes dans cette zone de savane. Six différents types d'utilisation des terres sur 9 parcelles expérimentales répartis à l’échelle du paysage du centre-sud de la Côte d’Ivoire ont été comparé : (i) le brûlis comme pratique traditionnelle ; (ii) la fertilisation chimique comme pratique conventionnelle ; et le mulching comme pratique innovante, testé (iii) sans insertion de légumineuses ou (iv et v) avec insertion de haricot ou soja dans des cycles de rotations culturales ; (vi) le sol nu était considéré comme une situation de référence (le témoin). Le sol a été prélevé dans 54 sous-parcelles, avant et 3 fois après la mise en place des traitements. Sept activités enzymatiques (activités dénitrifiante, nitrifiante, β glucosidase, N-acétyl-β-D-glucosaminidase, phosphatase acide et alcaline, déshydrogénase) du sol, les principales variables du sol (humidité, carbone organique, azote total, pH et Phosphore assimilable), l'abondance et la diversité des communautés microbiennes impliquées dans le cycle de l’azote (bactéries et archées oxydatrices de l’ammonium ; les genres Nitrobacter et Nitrospira qui jouent un rôle clé dans la production de nitrate ; les bactéries réductrices du nitrite porteuses des gènes nirS ou nirK ; et les bactéries réductrices du N2O porteuses de gènes nosZI ou nosZII). Les résultats ont montré que (i) le C. org, le K, le Mg et les activités enzymatiques du sol ont diminué avec la profondeur du sol, indiquant un faible taux d’accumulation des nutriments dans les profondeurs les plus importantes du sol. Par ailleurs, les durées de jachère (0 à 10 ans) n’ont pas significativement affecté la majorité des propriétés du sol, à l'exception de l’Ntot et du K du sol qui étaient élevés dans les vieilles jachères. De plus, le C. org a diminué en fonction de la durée de la jachère tandis que le Mg a suivi une tendance inverse ; (ii) le type d'utilisation des terres a affecté fortement la plupart des activités enzymatiques du sol et les communautés microbiennes impliquées dans le cycle de l’azote; (iii) les pratiques de mulching pourraient avoir un impact positif sur les caractéristiques du sol et les communautés microbiennes, avec pour conséquence le renforcement du maintien de la fertilité des sols et la durabilité de la production agricole à long terme. D’après les résultats obtenus, la pratique de paillage, possiblement avec insertion de légumineuses, pourrait être moins onéreuse et plus adaptée pour augmenter progressivement et de façon durable la disponibilité en azote dans ces agroécosystèmes / In West Africa, humid savanna soils are characterized by extremely low concentrations of organic matter, mineral nitrogen, phosphorus and basic cations, which limit primary production. We analyzed how particular changes in land-uses can influence the functioning and fertility of soils, to support the production of agroecosystems in this savanna zone. We compared six land-use types at 9 experimental plots across a landscape: traditional slash-and-burn; conventional chemical fertilization; and innovative use of mulching (tested with or without inserting legumes in the crop rotation). Bare soil was also considered as a reference situation. Soil was sampled on the 54 sub-plots, before and 3 times after treatment inception. We surveyed seven soil enzyme activities (denitrification, nitrification, β glucosidase, N-acetyl-β-D-glucosaminidase, acid and alkaline phosphatase, dehydrogenase), key soil variables (moisture, organic C, mineral and total N, pH, and available P) and the abundances and diversity of microbial communities involved in the N cycle (bacterial and archaeal ammonia oxidizers; Nitrobacter; Nitrospira; and nirS-, nirK- and nosZ-like denitrifiers). Our results showed that (i) C. org, K, Mg and soil enzymes activities decreased with soil depth, reflecting a low rate of nutrient accumulation in soil depth. In contrast, fallow periods (0 to 10 years) did not significantly affect the majority of soil properties, excepted soil Ntot and K, which were high in old fallows. In addition, C. org decreased as a function of the fallow period, but Mg follow-up an inverse trend; (ii) the land use type strongly affects most soil enzymatic activities and the microbial communities involved in nutrient cycling; (iii) innovative mulching practices have a positive impact on soil characteristics and microbial communities, thereby maintaining the maintenance of soil fertility and the sustainability of agricultural production in the long term. According to our results, the practice of mulching, possibly with the insertion of legumes, could be less expensive and more appropriate to progressively and sustainably increase nitrogen availability in these agro-ecosystems

The ability of Chromolaena odorata propagated by stem cuttings and grown for six weeks in the greenhouse to thrive in soil containing different concentrations of PCB congeners found in Aroclor and transformer oil, and to possibly remediate such soil was studied under greenhouse conditions. Chromolaena odorata plants were transplanted into soil containing 100, 200, and 500 ppm of Aroclor and transformer oil (T/O) in 1L pots. The experiments were watered daily at 70% moisture field capacity. Parameters such as mature leaves per plant, shoot length, leaf colour as well as the root length at harvest were measured. C. odorata growth was negatively affected by T/O in terms of shoot length and leaf numbers, but no growth inhibition was shown by Aroclor. At the end of six weeks of growth, Plants size was increased by 1.4 and 0.46%, but decreased at -1.0% in T/O, while increases of 45.9, 39.4 and 40.0% were observed in Aroclor treatments. Mean total PCB recoveries were 6.40, 11.7, and 55.8μg in plants tissues at Aroclor treated samples resulting in a percentage reduction of PCB from the soil to 2.10, 1.50, and 1.10 at 100, 200, and 500mg/kg Aroclor treatments respectively. There was no PCB recovery from plants in transformer oil treatments as a result of its inhibition to growth. Root uptake was found to be the probable means of remediation of PCB-contaminated soil by C. odorata, this was perhaps aided by microbes. This study has provided evidence on the ability of C. odorata to remediate PCB contaminated soil. However, the use of C. odorata for phytoremediation of PCB contaminated soil under field condition is therefore advised. / Environmental Sciences / M.Sc. (Environmental Science)

Les premières souches bactériennes résistantes aux antibiotiques sont connues depuis 70 ans et se sont multipliées ces dernières années posant un grave problème de santé publique. Parmi les nombreux types d’infections induites par ces bactéries, nous nous sommes intéressés aux infections intestinales qui peuvent dégénérer en maladies inflammatoires de l’intestin et cancers. Notre travail de thèse a consisté à proposer des outils thérapeutiques dans le traitement des pathologies intestinales infectieuses : des peptides antimicrobiens dérivés de la chromogranine A et des extraits de plantes de la médecine traditionnelle béninoise. La chromogranine A est une protéine libérée par les cellules nerveuses, neuroendocrines et immunitaires au cours d’un stress et maturée en peptides. Des peptides actifs contre quatre souches bactériennes pathogènes (Klebsiella oxytoca, Salmonella enterica, Shigella sonnei et Vibrio cholera non O1) ont été identifiés et l’interaction bactérie-peptide analysée. L’étude de la combinaison peptide-antibiotique montre que la cateslytine permet de réduire les doses d’antibiotiques nécessaires. Ensuite, nous avons étudié l’implication de deux peptides sur un modèle de cellules neuroendocrines, les cellules BON. La chromofungine provoque la stimulation des cellules BON en induisant un influx de calcium extracellulaire, tandis que la catestatine est capable de bloquer l’activité de la chromofungine.Après un screening des extraits de 14 plantes du Bénin, nous avons isolé deux molécules, la sinensétine et l’O-tétraméthyléther scutellaréine, responsables de l’activité antibactérienne de Chromolaena odorata contre les pathogènes étudiés. / The first bacterial strains resistant to antibiotics appeared 70 years ago and have proliferated in recent years causing a serious public health problem. Such bacteria are responsible of several types of infections including intestinal infections with chronic inflammatory bowel diseases and cancers. This work consisted of proposing new therapeutic tools in the treatment of intestinal pathologies. In this context, we have studied antimicrobial peptides derived from chromogranin A and plant extracts used in Beninese traditional medicine for the treatment of such diseases. Chromogranin A is a protein produced by nervous, endocrine and immune cells during a stress and processed to generate biologically active peptides. We identified antimicrobial peptides, active against four pathogenic bacterial strains (Klebsiella oxytoca, Salmonella enterica, Shigella sonnei and Vibrio cholera non O1) and analyzed the bacteria-peptide interactions. Moreover, the study of the peptide-antibiotic combination shows that cateslytin is useful for reducing doses of antibiotic drugs. In addition of this work, we have studied the effects of two peptides derived from chromogranin A on neuroendocrine cells with model of BON cells. Chromofungin stimules BON cells by inducing an influx of extracellular calcium, whereas catestatin is able to block chromofungin’s activity.With plant extracts, after a screening on 14 plants from Benin, our works enabled us to isolate two active molecules, sinensetin and O-tetramethylether scutellarein, responsible of the antimicrobial activity of Chromolaena odorata against the studied pathogenic strains.

The ability of Chromolaena odorata propagated by stem cuttings and grown for six weeks in the greenhouse to thrive in soil containing different concentrations of PCB congeners found in Aroclor and transformer oil, and to possibly remediate such soil was studied under greenhouse conditions. Chromolaena odorata plants were transplanted into soil containing 100, 200, and 500 ppm of Aroclor and transformer oil (T/O) in 1L pots. The experiments were watered daily at 70% moisture field capacity. Parameters such as mature leaves per plant, shoot length, leaf colour as well as the root length at harvest were measured. C. odorata growth was negatively affected by T/O in terms of shoot length and leaf numbers, but no growth inhibition was shown by Aroclor. At the end of six weeks of growth, Plants size was increased by 1.4 and 0.46%, but decreased at -1.0% in T/O, while increases of 45.9, 39.4 and 40.0% were observed in Aroclor treatments. Mean total PCB recoveries were 6.40, 11.7, and 55.8μg in plants tissues at Aroclor treated samples resulting in a percentage reduction of PCB from the soil to 2.10, 1.50, and 1.10 at 100, 200, and 500mg/kg Aroclor treatments respectively. There was no PCB recovery from plants in transformer oil treatments as a result of its inhibition to growth. Root uptake was found to be the probable means of remediation of PCB-contaminated soil by C. odorata, this was perhaps aided by microbes. This study has provided evidence on the ability of C. odorata to remediate PCB contaminated soil. However, the use of C. odorata for phytoremediation of PCB contaminated soil under field condition is therefore advised. / Environmental Sciences / M.Sc. (Environmental Science)

Several alien plants are invading subtropical forest ecosystems through canopy gaps, resulting in the loss of native species biodiversity. The loss of native species in such habitats may result in reduced ecosystem functioning. The control and eradication of these invaders requires accurate mapping of the levels of invasion in canopy gaps. Our study tested (i) the utility of WorldView-2 imagery to map forest canopy gaps, and (ii) an integration of WorldView-2 data with environmental data to model the probability of occurrence of invasive Chromolaena odorata (triffid weed) in Dukuduku forest canopy gaps of KwaZulu- Natal, South Africa. Both pixel-based classification and object-based classification were explored for the delineation of forest canopy gaps. The overall classification accuracies increased by ± 12% from a spectrally resampled 4 band image similar to Landsat (74.64%) to an 8 band WorldView-2 imagery (86.90%). This indicates that the new bands of WorldView such as the red edge band can improve on the capability of common red, blue, green and near-infrared bands in delineating forest canopy gaps. The maximum likelihood classifier (MLC) in pixel-based classification yielded the overall classification accuracy of 86.90% on an 8 band WorldView-2 image, while the modified plant senescence reflectance index (mPSRI) in object-based classification yielded 93.69%. The McNemar’s test indicated that there was a statistical difference between the MLC and the mPSRI. The mPSRI is a vegetation index that incorporates the use of the red edge band, which solves a saturation problem common in sensors such as Landsat and SPOT. An integrated model (with both WorldView-2 data and environmental data) used to predict the occurrence of Chromolaena odorata in forest gaps yielded a deviance of about 42% (D2 = 0.42), compared to the model derived from environmental data only (D2 = 0.12) and WorldView-2 data only (D2 = 0.20). A D2 of 0.42 means that a model can explain about 42% of the variability of the presence/absence of Chromolaena odorata in forest gaps. The Distance to Stream and Aspect were the significant environmental variables (ρ < 0.05) which were positively correlated with presence/absence of Chromolaena in forest gaps. WorldView-2 bands such as the coastal band (λ425 nm) yellow band (λ605 nm) and the nearinfrared- 1 (λ833 nm) are positively and significantly related to the presence/absence of invasive species (ρ < 0.05). On the other hand, a significant negative correlation (ρ < 0.05) of near-infrared-2 band (λ950 nm) and the red edge normalized difference vegetation index (NDVI725) suggests that the probability of occurrence of invasive Chromolaena increases forest gaps with low vegetation density. This study highlights the importance of WorldView- 2 imagery and its application in subtropical indigenous coastal forest monitoring. / Thesis (M.Sc.)-University of KwaZulu-Natal, Pietermaritzburg, 2013.

The flavone 3,5,7-trihydroxy-6-methoxyflavone was isolated from leaf extracts of Chromolaena leivensis (Hieron), commonly named plant of cancer. It was identified based on their physicochemical propierties and spectroscopic data. This compound presented a methoxylation at C6, this is uncommon in flavonoids and which may confer some specificity of its biological activity. The cytotoxic activity of this flavonoid was determined on PC3 (prostate), MDA- MB-231 (breast), HT29 (colon), SiHa (cervix) and A549 (lung) cancer cells, using MTT assay, to assess if the flavonoid contributes to the anticancer activity previously proposed for Chromolaena leivensis. The cytotoxic activity of the 3,5,7-trihydroxy-6- methoxy flavone was similar to that obtained for the flavonoid quercetin but was low compared with the positive control vincristine sulphate. The better value of the inhibitory concentration of fifty percent (IC50) 150 μ M, was achieved on SiHa cell line, while the lower activity: 4008 μ M, was obtained on HT29 cancer cell line. However, severe morphological changes were detected on cytoskeleton and nucleus of the SiHa cells detected by immunofluorescence microscopy analysis of cells exposed to the half of the IC50 concentration obtained for the flavonoid. Data indicate that the flavonoid contributes to the anticancer activity of the extracts of leaves from Chromolaena leivensis, and could broadening the spectrum of flavonoids activity against various types of cancer non hormone-dependent.