Abstract The study evaluated the effect of different cryoprotectants on post-thaw survival and motility of Kolbroek sperm. Semen from Kolbroek boars was collected with the gloved hand technique. Ejaculates were diluted with Beltsville thawing solution (BTS) at a ratio of 1 : 1 prior to freezing. Semen was diluted with egg yolk tris; thereafter, one of the three cryoprotectants (14% glycerol, 14% DMSO or 7% glycerol + 7% DMSO) were added. Diluted samples were then loaded into 0.5 mL straws and cooled with a programmable freezer. Thereafter the semen straws were plunged directly into liquid nitrogen (-196 °C) and stored for 48 h. Frozen straws were thawed at 39 °C for a minute and evaluated for sperm motility and survival at 0, 30, 60 and 90 min post-thaw. The post-thaw sperm survival frozen using glycerol as a cryoprotectant was significantly higher immediately after thawing, compared to DMSO, however, similar to the combination of glycerol and DMSO. There was no significant difference on motility rate immediately (0 min) post-thaw between the three cryoprotectants. Sperm cryopreserved with glycerol exhibited a significantly higher percentage motility at 30, 60 and 90 min post-thaw than in the other cryoprotectants. Based on sperm motility, glycerol was a better cryoprotectant for cryopreservation of Kolbroek boar sperm.

Thesis (MSc. (Biochemistry)) -- University of Limpopo, 2013 / Hydroxynitrile lyases (HNLs) are enzymes that catalyse enantioselective cleavage of the substrate in a reaction and are also used as important industrial biocatalysts for the synthesis of chiral cyanohydrins. The aim of the study was to screen indigenous South African plants for potential hydroxynitrile lyase activity, purify and biochemically characterise the active hydroxynitrile lyase(s) from the selected plants. Several indigenous plants were randomly collected, identified and screened for HNL activity. The plant parts (leaves, seeds or fruits) were processed using established experimental protocols in order to obtain the crude enzyme extracts. The enzymatic conversion of benzaldehyde and potassium cyanide to mandelonitrile was optimised and consequently used for the screening of HNL activity. Enzyme activity was detected in the crude enzyme extracts of Kalanchoe spp and Senecio spp and these were then designated as Ks and Sb, respectively. Ammonium sulphate fractionation, DEAE Toyopearl 650M and Concanavalin A chromatography techniques were then used in the purification process of the active crude enzyme extracts. Subsequently, two purified active fractions were isolated from each plant species with molecular masses estimated at 64.64 kDa and 64.06 kDa for the KsHNL enzymes and 70.60 kDa and 74.04 kDa for SbHNL enzymes. The optimum temperature and pH of all the isolated enzymes were determined as 50°C and pH 5, respectively. The experimental Km and Vmax values of the enzymes were respectively determined to be 0.33 and 0.73 mM and 1.238 and 1.948 μM/min for KsHNL; while that for SbHNL enzymes were 5.86 and 0.22 mM and 9.741 and 1.905 μM/min. The effect of additives and metal ions (viz., DTT, DEP, mercury chloride, magnesium chloride and zinc chloride) was determined. The experimental data obtained alluded to the notion that both KsHNL and SbHNL enzymes may contain the cysteine and serine residues next to their active sites and that a histidine residue may be involved in the catalytic activities of both the isolated KsHNL enzymes and one of the SbHNL enzymes. All the isolated enzymes from the two plant species did not seem to contain an FAD group. These findings compared favourably to the theoretical type II HNLs, although with a slight difference in that they displayed high molecular weights. Kalanchoe spp and Senecio spp are the two indigenous South African plants that were found to contain active HNLs. The isolated HNLs from the two plants have a potential to be xv purified to homogeneity, cloned and overexpressed into robust recombinant enzymes that can be used for large scale industrial applications.

ENGLISH : The use of different characteristics (the polyphasic approach) to describe bacterial taxa is a prerequisite for a stable classification. The taxonomy of root- and stem-nodulating rhizobia is in a state of transition. As more legumes are studied, new species and genera of rhizobia are described. It is important to study the indigenous South African rhizobia, as without them a complete rhizobial taxonomy is not possible. Furthermore, strains with superior nitrogen fixation abilities may be discovered. Indigenous strains better adapted to the harsh South African environment are possible candidates for commercial inoculants for cropped legumes.Only two local studies have been done on the diversity of the indigenous rhizobia. These studies revealed the diversity of rhizobia existing in the South African context. As part of a polyphasic approach used to identify and determine the diversity of the indigenous rhizobia, 16S rDNA sequencing analysis was performed on some selected rhizobial and putative rhizobial isolates. The aim of the study was to characterise and identify the indigenous isolates by 16S rDNA sequencing analysis and compare our data with those available in the GenBank database. Results showed that most of the indigenous isolates were slow-growers belonging to the genus Bradyrhizobium. Two isolates from supposedly non-nodulating legume genera (Cassia and Senna) were found to belong to the genus Bradyrhizobium. Some of the isolates were shown to belong to the genera Mesorhizobium, Rhizobium and Sinorhizobium. The identity of five isolates was not clear and further studies need to be performed to unequivocally determine their taxonomic position. Partial sequence analysis of 16S rDNA proved a valuable tool to characterise and identify the indigenous isolates. However, the method was unable to clearly distinguish between closely related species and strains. AFRIKAANS : 'n Stabiele klassifikasiesisteem vir die beskrywing van bakteriese taksa is slegs moontlik deur verskillende eienskappe (die poli-fasiese benadering) te gebruik. Die taksonomie van die wortel- en stamnodulerende rhizobiums verander gedurig. 'n Volledige rhizobiumtaksonomie is slegs moontlik indien die inheemse Suid-Afrikaanse rhizobiums bestudeer word. Geharde inheemse rasse met voortreflike stikstofbindende vermoens kan ontdek word. Hierdie rasse is kandidate vir kommersiele inokulums vir verboude peulplante. Net twee plaaslike studies is gedoen om die diversiteit van die inheemse rhizobiums te bepaal. Die studies het bewys dat die inheemse rhizobiums baie divers is. As deel van die polifasiese benadering om die diversiteit van die inheemse rhizobiums te identifiseer en te bepaal, is 16S rDNS volgordebepaling gedoen op uitgesoekte rhizobia en sogenaamde rhizobia isolate. Die doel van die studie was die karakterisering en identifisering van die inheemse isolate deur 16S rDNS volgordebepaling en die vergelyking van die data met die beskikbaar in die GenBank databasis. Die resultate wys dat die meeste inheemse isolate stadige groeiers is en dus behoort aan die genus Bradyrhizobium. Twee isolate vanaf sogenaamde nie-nodulerende peulplantgenusse (Cassia en Senna) behoort ook tot die genus Bradyrhizobium. Sommige isolate behoort tot die genusse Mesorhizobium, Rhizobium en Sinorhizobium. Die identiteit van vyf isolate was nie duidelik nie en verdere studies is nodig om hul taksonomiese posisie ondubbelsinnig te bepaal. Die gedeeltelike volgordebepaling van die 16S rDNS was 'n waardevolle hulpmiddel om die inheemse isolate mee te karakteriseer en te identifiseer, alhoewel die metode nie tussen nabyverwante spesies en rasse kon onderskei nie. Copyright / Dissertation (MSc (Microbiology))--University of Pretoria, 1999. / Microbiology and Plant Pathology / unrestricted

Made available in DSpace on 2015-04-11T13:59:33Z (GMT). No. of bitstreams: 1 Joao Vianna.pdf: 2442755 bytes, checksum: 091c650feb0227d1309e98a5b2065d5f (MD5) Previous issue date: 2013-05-08 / Conselho Nacional de Desenvolvimento Científico e Tecnológico / While the ethnographic literature of lowland South America has provided a vast amount of material, though scattered, on Amerindian illness, it has rarely been taken as a central theme. Many of the studies of this ethnographic area, especially those related to topics such as shamanism, show implicitly or explicitly, indigenous perceptions of the process of illness. This dissertation focuses precisely on the conceptualization of illness and way of becoming sick among the Baniwa of the Upper Rio Negro, in north-western Amazonia. This research does not only arise from theoretical concerns and concepts of illness but from a specific event that has been occurring in the indigenous school of differentiated education Baniwa e Coripaco (EIBC) Pamáali on the middle Içana river. The forms of illness concerned are of traditional nature and have affected the pupils of this school for eight years, causing concern for parents, teachers, leaders and others involved. This work aims to reveal aspects of Amerindian conceptions of illness and through these hopes to problematize current collaborative projects between indigenous and non-indigenous organizations / A literatura etnológica das terras baixas da América do Sul dedicou-se com pouco afinco ao estudo das doenças enquanto temática central, o que não significa, contudo, que esta mesma literatura não forneça um vasto material, ainda que disperso, sobre o adoecimento ameríndio. Muitos dos trabalhos realizados nesta paisagem etnográfica, principalmente aqueles ligados a temas como xamanismo, transparecem entre suas linhas, implícita ou explicitamente, as concepções que estes povos elaboram a respeito do processo de adoecimento. Esta dissertação tem justamente nas doenças e nas formas de adoecimento entre os Baniwa - Alto Rio Negro, Noroeste Amazônico - objeto privilegiado de estudo. A pesquisa, no entanto, não surge somente de preocupações teóricas a partir da constatação de problemáticas pouco estudadas, mas de um evento específico que está a ocorrer na escola indígena Baniwa e Coripaco (EIBC) Pamáali, na região do médio rio Içana. Trata-se de formas tradicionais de adoecimento que há oito anos incide em alunos desta escola modelo de educação diferenciada, provocando preocupação em pais, professores, lideranças e nos demais envolvidos. Este trabalho pretende revelar aspectos relacionados às concepções ameríndias de doença e, por meio delas, reflexões a respeito de projetos desenvolvidos por associações indígenas, em cooperação com entidades indigenistas

Text in Afrikaans / In die verhandeling word die vergestalting van die sprokiemotief in die tekste, Griet skryf 'n sprokie deur Marita van der Vyver (1992) en Weerkaatsings - 'n sprokie deur Eleanor Baker (1984) nagegaan. Die doel is om vas te stel op watter wyse hierdie "kindgerigte" genre op die literere vlak van die volwasse leser omvorm word. Om hierdie doel te bereik word eerstens 'n begripsverkenning van die sprokie as epiese genre gedoen. In die verkenning van die genre val die soeklig nie net op die Westerse sprokie nie, maar daar word ook gefokus op die inheemse SuidAfrikaanse sprokie. Tweedens word aan die hand van hierdie teoretiese raamwerk 'n noukeurige analise gemaak van die vergestalting van die sprokiemotief binne die twee primere tekste. Die sprokieselemente in Griet skryf 'n sprokie en Weerkaatsings - 'n sprokie word uitgelig en die hantering daarvan vergelykend ondersoek / In the dissertation the manifestation of the fairytale motif in the texts, Griet skryf 'n sprokie by Marita van der Vyver (1992), and Weerkaatsings 'n sprokie by Eleanor Baker (1984) is investigated. The purpose is to ascertain the manner in which this "child-centred" genre is transformed on the literary level of the adult reader. To achieve this goal, a conceptualization of the fairytale as an epic genre is firstly undertaken. In the exploration of the genre, the search light does not only focus on the Western but also on the indigenous South African fairytale. Secondly, by means of this theoretical framework, a detailed analysis is made of the manifestation of the fairytale motif in the two primary texts. The elements of the fairytale in Griet skryf 'n sprokie and Weerkaatsings - 'n sprokie are highlighted and the handling thereof comparatively investigated / Afrikaans & Theory of Literature / M.A. (Afrikaans)

Text in Afrikaans / In die verhandeling word die vergestalting van die sprokiemotief in die tekste, Griet skryf 'n sprokie deur Marita van der Vyver (1992) en Weerkaatsings - 'n sprokie deur Eleanor Baker (1984) nagegaan. Die doel is om vas te stel op watter wyse hierdie "kindgerigte" genre op die literere vlak van die volwasse leser omvorm word. Om hierdie doel te bereik word eerstens 'n begripsverkenning van die sprokie as epiese genre gedoen. In die verkenning van die genre val die soeklig nie net op die Westerse sprokie nie, maar daar word ook gefokus op die inheemse SuidAfrikaanse sprokie. Tweedens word aan die hand van hierdie teoretiese raamwerk 'n noukeurige analise gemaak van die vergestalting van die sprokiemotief binne die twee primere tekste. Die sprokieselemente in Griet skryf 'n sprokie en Weerkaatsings - 'n sprokie word uitgelig en die hantering daarvan vergelykend ondersoek / In the dissertation the manifestation of the fairytale motif in the texts, Griet skryf 'n sprokie by Marita van der Vyver (1992), and Weerkaatsings 'n sprokie by Eleanor Baker (1984) is investigated. The purpose is to ascertain the manner in which this "child-centred" genre is transformed on the literary level of the adult reader. To achieve this goal, a conceptualization of the fairytale as an epic genre is firstly undertaken. In the exploration of the genre, the search light does not only focus on the Western but also on the indigenous South African fairytale. Secondly, by means of this theoretical framework, a detailed analysis is made of the manifestation of the fairytale motif in the two primary texts. The elements of the fairytale in Griet skryf 'n sprokie and Weerkaatsings - 'n sprokie are highlighted and the handling thereof comparatively investigated / Afrikaans and Theory of Literature / M.A. (Afrikaans)