<p>Extracts from the root bark, stem bark, and leaves of R. natalensis were screened for antibacterial activity against standard bacterial strains / Staphylococcus aureas, Escherichia coli and Pseudomonas aureginosa, and fungi / Candida albicans, Trichophyton mentagrophytes or Microsporum gyseum. Chromatographic techniques were utilized to isolate pure compounds. This study validates and documents, in a systematic way, the antimicrobial properties of the R. natalensis used for many years by many people of the world. It also provides valuable information for&nbsp / further phytochemical isolation and characterization studies of active compounds, necessary for the development of new drugs. The extractions were carried out using broad spectrum of solvents&nbsp / (hexane, dichloromethane, ethyl acetate, and methanol). Fractionation was done using standard chromatographic techniques. A total of seven (7) compounds were isolated from R. natalensis.&nbsp / Three of the isolates were characterized and their structures were unambiguously established by detailed spectroscopic analysis that involved high resolution mass spectrometry, 1D and&nbsp / 2D-NMR spectral data experiments 1H, 13C, DEPT, COSY, HMBC, and NOESY. These compounds are: 3-(1-(2,4-dihydroxyphenyl)-3,3-bis(4- hydroxyphenyl)-1-oxopropan-2-yl)-7-methoxy- 4H-chromone-4-one (39), Rhuschromone, a&nbsp / novel compound isolated for the first time, 2&rsquo / ,4&rsquo / -dihydroxychalcone-(4-O-5&rsquo / &rsquo / &rsquo / )-4&rsquo / &rsquo / ,2&rsquo / &rsquo / &rsquo / ,4&rsquo / &rsquo / &rsquo / - trihydroxychalcone (40) and 3-((Z)-heptadec-13-enyl) benzene- 1,2-diol (41), an urushiol. Compound 39 recorded the highest activity zone of inhibition (21mm) against S. aureas, which was found to be 50% as active the chloramphenicol standard used. The&nbsp / traditional use of the extracts in infections and inflammatory conditions is rationalized based on the content of theisolated compounds, and it has been proposed that the total crude extract, with its&nbsp / contents of so many bioactive compounds, could be formulated for use in many infections, microbial or fungal. Furthermore, not all of the species studied to date have been fully characterized&nbsp / for potential bioactivities. Thus, there remains a significant research gap spanning the range from lead chemical discovery through process development and optimization in order to better&nbsp / understand the full bioactive potential of many of these plants.</p>

<p>Extracts from the root bark, stem bark, and leaves of R. natalensis were screened for antibacterial activity against standard bacterial strains / Staphylococcus aureas, Escherichia coli and Pseudomonas aureginosa, and fungi / Candida albicans, Trichophyton mentagrophytes or Microsporum gyseum. Chromatographic techniques were utilized to isolate pure compounds. This study validates and documents, in a systematic way, the antimicrobial properties of the R. natalensis used for many years by many people of the world. It also provides valuable information for&nbsp / further phytochemical isolation and characterization studies of active compounds, necessary for the development of new drugs. The extractions were carried out using broad spectrum of solvents&nbsp / (hexane, dichloromethane, ethyl acetate, and methanol). Fractionation was done using standard chromatographic techniques. A total of seven (7) compounds were isolated from R. natalensis.&nbsp / Three of the isolates were characterized and their structures were unambiguously established by detailed spectroscopic analysis that involved high resolution mass spectrometry, 1D and&nbsp / 2D-NMR spectral data experiments 1H, 13C, DEPT, COSY, HMBC, and NOESY. These compounds are: 3-(1-(2,4-dihydroxyphenyl)-3,3-bis(4- hydroxyphenyl)-1-oxopropan-2-yl)-7-methoxy- 4H-chromone-4-one (39), Rhuschromone, a&nbsp / novel compound isolated for the first time, 2&rsquo / ,4&rsquo / -dihydroxychalcone-(4-O-5&rsquo / &rsquo / &rsquo / )-4&rsquo / &rsquo / ,2&rsquo / &rsquo / &rsquo / ,4&rsquo / &rsquo / &rsquo / - trihydroxychalcone (40) and 3-((Z)-heptadec-13-enyl) benzene- 1,2-diol (41), an urushiol. Compound 39 recorded the highest activity zone of inhibition (21mm) against S. aureas, which was found to be 50% as active the chloramphenicol standard used. The&nbsp / traditional use of the extracts in infections and inflammatory conditions is rationalized based on the content of theisolated compounds, and it has been proposed that the total crude extract, with its&nbsp / contents of so many bioactive compounds, could be formulated for use in many infections, microbial or fungal. Furthermore, not all of the species studied to date have been fully characterized&nbsp / for potential bioactivities. Thus, there remains a significant research gap spanning the range from lead chemical discovery through process development and optimization in order to better&nbsp / understand the full bioactive potential of many of these plants.</p>

Magister Scientiae - MSc / Extracts from the root bark, stem bark, and leaves of R. natalensis were screened for antibacterial activity against standard bacterial strains; Staphylococcus aureas, Escherichia coli and Pseudomonas aureginosa, and fungi; Candida albicans, Trichophyton mentagrophytes or Microsporum gyseum. Chromatographic techniques were utilized to isolate pure compounds. This study validates and documents, in a systematic way, the antimicrobial properties of the R. natalensis used for many years by many people of the world. It also provides valuable information for further phytochemical isolation and characterization studies of active compounds, necessary for the development of new drugs. The extractions were carried out using broad spectrum of solvents (hexane, dichloromethane, ethyl acetate, and methanol). Fractionation was done using standard chromatographic techniques. A total of seven (7) compounds were isolated from R. natalensis. Three of the isolates were characterized and their structures were unambiguously established by detailed spectroscopic analysis that involved high resolution mass spectrometry, 1D and 2D-NMR spectral data experiments 1H, 13C, DEPT, COSY, HMBC, and NOESY. These compounds are: 3-(1-(2,4-dihydroxyphenyl)-3,3-bis(4- hydroxyphenyl)-1-oxopropan-2-yl)-7-methoxy- 4H-chromone-4-one (39), Rhuschromone, a novel compound isolated for the first time, 2’,4’-dihydroxychalcone-(4-O-5’’’)-4’’,2’’’,4’’’- trihydroxychalcone (40) and 3-((Z)-heptadec-13-enyl) benzene- 1,2-diol (41), an urushiol. Compound 39 recorded the highest activity zone of inhibition (21mm) against S. aureas, which was found to be 50% as active the chloramphenicol standard used. The traditional use of the extracts in infections and inflammatory conditions is rationalized based on the content of theisolated compounds, and it has been proposed that the total crude extract, with its contents of so many bioactive compounds, could be formulated for use in many infections, microbial or fungal. Furthermore, not all of the species studied to date have been fully characterized for potential bioactivities. Thus, there remains a significant research gap spanning the range from lead chemical discovery through process development and optimization in order to better understand the full bioactive potential of many of these plants. / South Africa

Made available in DSpace on 2014-06-12T16:24:49Z (GMT). No. of bitstreams: 2 arquivo1084_1.pdf: 1041782 bytes, checksum: 575848b1ff08dd59252a4745034cc38f (MD5) license.txt: 1748 bytes, checksum: 8a4605be74aa9ea9d79846c1fba20a33 (MD5) Previous issue date: 2010 / Euclea natalensis A. DC. pertence a família Ebenaceae e é encontrada na África Austral desde o Quênia e República Democrática do Congo até a África do Sul. Esta planta destaca-se popularmente pela pronunciada ação antibacteriana ao impedir a formação da placa bacteriana e antiinflamatória de seus metabólitos secundários, principalmente as naftoquinonas. Em revisão de literatura, constatou-se a carência de informações detalhadas para a área odontológica. Neste sentido, este trabalho teve como objetivo avaliar a atividade antimicrobiana frente a microrganismos patogênicos para a cavidade oral e determinar a toxicidade aguda do extrato bruto etanólico da raiz de Euclea natalensis. Diante deste relato foi utilizado método de microdiluição em caldo Mueller Hinton para a determinação da concentração inibitória mínima (CIM) frente aos seguintes microrganismos Streptococcus agalactiae, Streptococcus mutans, Streptococcus pyogenes, Staphylococcus aureus, Porphyromonas gingivalis e algumas cepas de Candida albicans obtidas do Instituto Nacional de Controle de Qualidade em Saúde (INCQS) e Depto. de Antibióticos da UFPE e teste de toxicidade aguda. Na análise microbiológica, os resultados foram satisfatórios comparando com a clorexidina frente aos microrganismos ensaiados. Desta forma, foi observado que o extrato bruto das raízes de Euclea natalensis A.DC. possui atividade antimicrobiana possivelmente correlacionada a presença de naftoquinonas. Para o ensaio de toxicidade aguda por via oral em Ratos Wistar, realizado pelo método de Trevan (1927), foi administrada uma dose de 4mL de 6/6 horas, numa concentração de 5g/Kg, aos animais durante 24 horas e posteriormente foram observados em relação ao comportamento, consumo de água e alimento. Foi observado que os animais não apresentaram sinais clínicos de toxicidade, nem alteração no consumo de água e ração. Dessa forma conclui-se que o extrato bruto de Euclea natalensis A.DC. apresentou atividade antimicrobiana frente aos microorganismos testados e não possui toxicidade aguda

Very little is known about the post-shedding seed behaviour and megagametophyte development of the cycads, the most primitive extant seed-bearing plants, which pre-date the dinosaurs. In the present investigation, seeds of Encephalartos natalensis Dyer and Verdoorn were shed with relatively high mean embryo (3.33 g g-1) and megagametophyte (1.25 } 0.16 g g-1) WCs, when the developing embryo consisted primarily of the coiled, elongated suspensor bearing a rudimentary sporophyte at its tip. It was not surprising that these seeds were revealed as desiccation sensitive in the present investigation, as the embryos continued to develop after seed-shed, reaching a germinable size (.15 mm) only 4 . 6 months after seed abscission from the strobilus. Maintenance of the seeds in hydrated storage conditions was precluded by the proliferation of fungi, despite the application of the fungicide: BenlateR. Some seeds were also found to germinate in hydrated storage, despite the hard physical barrier to germination imposed by the enclosing sclerotesta. Seeds dusted with BenlateR and placed in eopen f storage in loosely closed paper bags had a longer life-span than those placed in hydrated storage; however, seeds stored in open storage were also overcome by fungi, but only around 18 months after seed-shed. Therefore, while the vigour and viability of the seeds appeared to decline slowly in the months after the embryos reached a germinable size, the life-span of stored E. natalensis seeds devoid of fungi is yet to be determined and will be the subject of further research. The current investigation also combined ultrastructural and viability retention studies to observe the post-shedding behaviour of the storage tissue, the megagametophyte. The cells of the megagametophyte became progressively packed with starch and protein as the two main storage reserves, a limited number of discrete lipid bodies, and occasional mitochondria all of which appeared to be embedded in an homogeneous matrix. When the development of the megagametophyte cells was analysed ultrastructurally, it was found that the unusual matrix was present from the inception of megagametophyte cellularisation, and contained microtubules and numerous very faintly-visible vesicles. Newly-formed megagametophyte cells were thus not highly vacuolated as previously thought, but dominated by an homogeneous matrix. Enzyme-gold localisation was employed in an attempt to determine the organelles responsible for the deposition of cell wall components during cellularisation of the megagametophyte. It appeared that ER-derived vesicles (and not Golgi-derived vesicles) were the principal contributors of the primary cell wall components, pectin and xylan. While cellularisation took place over approximately 1 - 2 weeks, subsequent development of the megagametophyte cells involved the accumulation of storage reserves, this phase lasting approximately 8 months -when the seeds were shed whether pollination/fertilisation had recently occurred, or not. At seed-shed, the cells of the megagametophyte were nucleated and contained a few mitochondria of a metabolically-active appearance. The occurrence of aerobic metabolism in these cells was confirmed by the tetrazolium (TTZ) test. Judging from the TTZ reactivity, the viability of the megagametophyte cells of fertilised seed appeared to decline slowly in the months after seed-shed, in parallel with extension growth of the embryo. The cell layer comprising the external surface of the megagametophyte showed marked ultrastructural differences from the inner cells, and may emerge as having an ‘aleurone-like’ function. It is, however, possible that the cells of the body of the gametophyte participate actively – at least in the earlier stages of post-shedding seed development – in mobilisation of stored reserves, which must support the development of the embryonic sporophyte. / Thesis (M.Sc.)-University of KwaZulu-Natal, Westville, 2009.

In South Africa, large quantities of Scilla natalensis are harvested from wild populations and sold as traditional medicine, which is reducing the density, distribution and genetic diversity of wild populations. The enforcement of existing legislation, however, has proved ineffective with plants being traded locally and internationally. It has therefore, been suggested that ex situ conservation through cultivation may alleviate pressures on natural resources. Conventional propagation of these plants, however, is usually fairly slow. In vitro propagation provides a rapid means of propagating selected chemotypes or cultivars, serving both conservation and commercial interests. In the first part of the study, continuous culture systems were established for the three forms of Scilla natalensis, S. natalensis sensu stricto (Form A), S. natalensis syn. S. kraussii (Form B) and S. natalensis syn. S. dracomontana (Form C). The efficiency of the systems was strongly influenced by genetic factors, viz the form and epigenetic factors, viz the explant type, carbohydrate source, plant growth regulators and gelling agents. The form, Form A, Form B or Form C respectively, influenced shoot initiation with the larger forms generally producing more shoots than the smaller forms (Form A > Form B > Form C). The data confirmed that the three forms are significantly different in terms of their physiological response to carbohydrates, plant growth regulators and gelling agents in vitro. Since the effect of form could not be compensated for by the addition of either carbohydrates, plant growth regulators or gelling agents, this may provide some support for the reinstatement of these forms as three species, Scilla natalensis Planch., S. kraussii Bak. and S. dracomontana Hilliard & Burtt. The explant type, that is bulb or leaf explants respectively, significantly influenced shoot initiation. Leaf explants generally produced more shoots than bulb explants. The carbohydrate source significantly influenced shoot initiation. The explants generally produced more shoots when cultured on media containing glucose or sucrose than on media containing fructose, lactose, maltose and particularly mannitol. The combination of cytokinins and auxins significantly influenced shoot initiation. Shoot initiation was higher for combinations of kinetin: IAA than for combinations of kinetin: NAA or TDZ: NAA. Optimal shoot initiation for Form A, Form B and Form C occurred on media containing 1 to 2 mg I-1 kinetin and 1 to 2 mg I-1 IAA. The gelling agent also influenced shoot initiation with media solidified with Gelrite® producing more shoots than media solidified with Oxoid or Unilab agar. Shoots were then rooted on media containing IAA, IBA or NAA and the plantlets were successfully acclimatised. These continuous culture systems can be used to produce large quantities of plantlets, which may alleviate pressures on natural resources and provide an alternative source of high quality plants for the burgeoning medicinal plant market. In the second part of the study, the effect of carbohydrate source and concentration on growth and development of shoots of S. natalensis syn. sensu stricto (Form A) were determined. This has applications for the acclimatisation and germplasm storage of bulbous plants. The carbohydrate source and concentration significantly influenced the growth and development of shoots. In the absence of carbohydrates, the shoots were short with spindly leaves and short roots. When media were supplemented with high concentrations of fructose, the shoots were long with broad leaves, small bulbs, and few short to medium length roots at low concentrations. At higher fructose concentrations, however, the shoots were robust and short with narrow, sometimes deformed leaves, large bulbs, and few stunted, brown roots. When sucrose was substituted for fructose, the shoots were robust and long with narrow and often red-pigmented leaves, large bulbs, and many long, thick roots. When AC was used in combination with sucrose, however, the shoots were robust and short with few, and occasionally red-pigmented leaves, small to medium bulbs, and few, severely stunted roots. Optimal shoot growth and development in terms of shoot weight (FW) and quality occurred on media containing glucose or sucrose (40 to 60 g I-1). The carbohydrate source and concentration also significantly influenced the physical properties of media particularly pH, electrical conductivity (EC) and gel-strength. The pH decreased slightly with increasing glucose concentration but decreased significantly with increasing fructose concentration when fructose was used alone or in combination with glucose. The pH also decreased significantly with increasing sucrose concentrations when sucrose was used in combination with Sigma AC. The EC decreased significantly with increasing fructose concentration when fructose was used alone but remained fairly constant irrespective of glucose concentration when glucose was used alone or in combination with fructose. The EC also remained fairly constant irrespective of the sucrose concentration but decreased with increasing sucrose concentration when used in combination with AC. The gel-strength remained fairly constant irrespective of glucose. The gel-strength decreased with increasing fructose concentration when used alone or in combination with glucose. The gel-strength of media increased with increasing sucrose concentration although the addition of Sigma AC significantly decreased the gel-strength of media, which decreased with increasing sucrose concentration. The brand and concentration of AC also influenced gel-strength. The matrix plot suggested that the effect of carbohydrate source and concentration on the growth of shoots may be largely due to the indirect effects of these physical properties such as hydrolysis of carbohydrates, the spectrum and quantity of the breakdown products and the availability of nutrients, plant growth regulators and water rather than the direct effects of pH, EC and gel-strength per se. / Thesis (Ph.D.)-University of Natal, Pietermaritzburg, 1999.

Monthly sampling of 71 laboratory nests, each with a pair of adults, revealed that eggs and first-instar larvae were observed in the third month, minor workers in the fourth month and minor soldiers in the seventh month. Mortality of the pairs was high, with only five pairs surviving over the 10 month period. Laboratory nests did not develop further than the copularium. Excavation of 30 nests, of differing sizes, revealed that five were juvenile nests, consisting of only thin shelving with a few flattened fungus combs scattered throughout, and all, even the youngest nest (3 to 5 years), had a small mound. The queens from these young nests were small and had white pleural and intersegmental membranes. Twenty mature nests had a medium to large mound with large air passages and a medium to large hive with a well defined fungus garden containing large fungus combs. The queens from these nests were medium- to large sized, with white to brown pleural and intersegmental membranes. The remaining five nests had mounds often covered with grass, and a hive that contained less fungus comb than expected. The mounds of these nests were classified using their sandy pediment or crumbly texture. These were senescent or declining nests. The queens had pale brown pleural membranes and brown intersegmental membranes, and were often flaccid. The royal cell was commonly found in the middle to upper part of the nursery (20 nests), but sometimes was found at the edge of the nursery (five nests). The royal cells of five nests were not found or had been destroyed during excavation. The "youngest" mound was one to two years old and the "oldest" was more than 25 years old. The youngest queen was estimated to be three to five years old and the oldest queen more than 27 years. The nest seems to remain subterranean for two or less years before producing a mound. Thirteen nests were vigorous and five declining. The remaining 12 nests could not be classified as no fungus comb was collected from the nests. / Thesis (M.Sc.)-University of Natal, Pietermaritzburg, 1997.

Thesis (Ph.D.), Faculty of Health Sciences, University of the Witwatersrand, 2009 / In recent years, there has been a growing interest in natural and traditional medicines for the treatment of wounds. Attempts to find agents that promote wound-healing and that are affordable, effective and non-toxic have a long history. In South Africa, hundreds of different indigenous plants are used to treat wounds and burns. The merits of relatively few of these have been scientifically evaluated. Bulbine natalensis and Bulbine frutescens of the Asphodelaceae family are indigenous to southern Africa and are widely used as a skin remedy. This study aimed to investigate the in vitro and in vivo effect of Bulbine natalensis and Bulbine frutescens on cutaneous wound healing. In vitro cell culture study: In vitro studies were carried out on dermal fibroblasts and human keratinocytes cultured under standard conditions using Iscove’s Modified Eagles Medium (MEM) and Dulbecco’s MEM respectively. Confluent cultures of both cell lines were treated with varying concentrations of the leaf extracts of B. frutescens and B. natalensis. These cultures were subjected to the MTT, WST-1 and BrdU assays to determine the cytotoxicity and proliferation effect of the extracts. In addition, migration of cells across a score was analysed over a 48 hour period. In vivo animal study: Excisional and incisional wounds were created on the back of 12 domestic pigs. Mirror imaged wounds were created as control wounds. The excisional wounds were biopsied at days 2, 4, 7, 10 and 16 and the incisional wounds were biopsied at day 16. The rate of closure of the wounds was also recorded. Each excisional wound was analyzed for its biochemical composition by estimating the total amount of protein, DNA, collagen and hexosamine that was present in the wound tissue. The wound healing process was documented histologically (using haematoxylin and eosin and a Mallory’s trichrome stain) and immunohistochemically (using anti- α smooth muscle actin, vascular endothelial growth factor WitsETD and transforming growth factor β receptors I and II). The incisional wounds were used to test tensile strength of the healed wounds using a tensiometer.In the in vitro studies, neither extract caused cytotoxicity to either the fibroblast or keratinocyte cells. Cell proliferation was greater than 100% at 0.1-5 and 100-300 μg/ml for Bulbine natalensis and at 0.1μg/ml for Bulbine frutescens. There was no significant difference in the effects of the two leaf extracts on cell proliferation. The biochemical analysis of the wound tissue showed a significant increase in the collagen, protein and total DNA content of both B frutescens and natalensis treated wounds when compared to the untreated wounds. There was no significant difference in the hexosamine content of both B. frutescens- and B. natalensis-treated and untreated wounds. Analysis of the wound tissue displayed an increase rate of closure of the wound tissue treated with B. frutescens and B. natalensis when compared to the untreated wounds. Full re-epithelialisation of both treated wounds occurred earlier than in the untreated wounds. These findings have important implications for the use of these extracts to treat wound healing.

Made available in DSpace on 2014-12-17T14:10:18Z (GMT). No. of bitstreams: 1 CarolinaMCAL.pdf: 705892 bytes, checksum: 2a31e2f6fe2a3d439e931aaeb7c530eb (MD5) Previous issue date: 2008-05-26 / Coleodactylus natalensis Freire, 1999, an endemic species of Atlantic Forest fragments around the Natal municipality, Rio Grande do Norte State, Brazil, has as type locality the Parque Estadual Dunas de Natal (05?48 S to 05?53 S and 35?09 W to 35?12 W), one of the largest restinga (herb and shrub association on sand dunes along the Brazilian coastline) associate fragment, surrounded by urban zone, placed on setentrional Atlantic Forest limits. We made estimates on populational density, spatial distribution, habitat and microhabitat preferences and feeding ecological aspects like sazonal and sexual variations on diet, prey electivities and niche breadth. We randomly sampled ninety-six 50m2 quadrants in each of the four habitats identified in the study area. Were collected 49 specimens and their stomach contents were analyzed; prey items found were correlated with leaf-litter invertebrates from habitat samples. We found a 98,5 ? 75,5 individuals/ha density, in grouped distribution pattern on densest habitats and random distribution on others habitats. This species lives mostly on leaf-litter in forest habitats, in higher humidity points, with lower temperatures, deeper leaf litter and lower sea level elevations than the randomly chosen points in the study area. Isopoda and Aranae were the most important prey categories in numeric, frequency and volumetric terms. Niche breadth has an intermediate value and was variable in sexual and in habitat terms. There was no correlation between morfometric measures and prey size on diet. The C. natalensis population studied seems to be diet opportunist, although selects larger prey items. The Parque Estadual das Dunas do Natal has several indications of anthropic pressure from the surrounding urban area that may affects the local C. natalensis population. Thus, the fragility of this species calls for urgent conservation efforts / Coleodactylus natalensis Freire, 1999, esp?cie end?mica de remanescentes de Mata Atl?ntica do Estado do Rio Grande do Norte, Brasil, tem como localidade-tipo o Parque Estadual Dunas de Natal (05?48 S a 05?53 S e 35?09 W a 35?12 W), um dos maiores remanescentes associados a restingas, cercado por zona urbana, situado no limite setentrional da Mata Atl?ntica. Foram realizadas estimativas de densidade populacional, distribui??o espacial, prefer?ncias de h?bitat e microh?bitat e aspectos da ecologia alimentar, tais como varia??es sazonais e entre sexos de dieta, eletividade de presas e largura de nicho. Amostramos aleatoriamente 96 quadrantes de 50m2 em cada um dos quatro h?bitats identificados na ?rea. Foram coletados 49 exemplares, que tiveram seus conte?dos estomacais analisados; os itens de presa encontrados foram correlacionados com amostras de invertebrados ed?ficos obtidas no ambiente. Encontramos uma densidade m?dia de 98,5 ? 75,5 indiv?duos/ha, com distribui??o agrupada nos h?bitats de maior densidade e rand?mica nos demais. A esp?cie habita preferencialmente o folhi?o de h?bitats de mata, em pontos mais ?midos, temperaturas mais amenas, folhi?o mais denso e menores eleva??es em rela??o ao n?vel do mar do que a m?dia da ?rea de estudo. As categorias de presa mais importantes na dieta foram Isopoda e Aranae. A largura de nicho foi m?dia e variou sexualmente e entre os h?bitats. N?o houve correla??o entre medidas morfom?tricas e tamanho das presas consumidas. A popula??o de C. natalensis estudada parece ser oportunista em termos de dieta, embora selecione presas relativamente maiores. O Parque das Dunas ? uma ?rea que sofre diversos tipos de press?o antr?pica que podem afetar a popula??o de C. natalensis. Deste modo, a fragilidade desta esp?cie na ?rea denota urg?ncia por medidas conservacionistas

Leishmaniasis is a disease circulating in endemic areas between sand flies (Diptera: Phlebotominae) and reservoir hosts, which - in the case of Leishmania major - are principally rodents (Rodentia). Unlike in human patients, leishmaniasis is often asymptomatic in animal hosts. For transmission and maintenance of the parasite in nature, infectiousness of hosts for sand flies is essential; and the only method to directly test the infectiousness is xenodiagnosis. The main objective of this thesis is to establish a laboratory model for studying xenodiagnosis with L. major on inbred BALB/c mice and then to apply this model to potential reservoir ro- dents from the genus Mastomys. BALB/c mice were infected by intradermal inoculation of infective stages of L. major (iso- lated from sand fly guts) together with salivary gland homogenates from Phlebotomus duboscqi; infected mice were then exposed to P. duboscqi females for a period of ten weeks. Two inbred lines of BALB/c mice differed significantly in both the manifestation of the disease and infectiousness for sandflies. In BALB/c OlaHsdmice, great lesions were formed (up to 10 mm), mice were able to infect sand flies from the 2nd week after infection and their infec- tiousness reached up to 20.1% during the experiment. In BALB/c AnNCrl mice, only small...