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Thesis (MSc)--Stellenbosch University, 2012. / ENGLISH ABSTRACT: Almost all processes during the life of a plant are affected by the environment. Changes in phytohormone, metabolite and protein levels follow in response to changes in the environment. Plant growth promoting substances can stimulate changes at these levels to facilitate increased plant growth and yields above what the plant would normally establish. In this study, the effects of two growth promoting substances, smoke water (SW) derived from bubbling smoke from the burning of plant material through water, and a synthetic strigolactone analogue, GR24, on plant growth and architecture, as well as the proteome and metabalome of salt stressed Nicotiana benthamiana seedlings were investigated. Physiological studies were conducted to identify the effects of the growth substances on salt stressed seedlings in a tissue culture system. Under non-stress conditions, SW treatment increased seedling fresh mass, root length and leaf area. Under salt stress conditions (100 mM and 150 mM NaCl), SW increased fresh mass, root length, leaf number and lateral root number significantly. Under non-stress conditions, GR24-treated seedlings showed increased fresh mass, leaf number and area and root length. When GR24-treated seedlings were placed under salt stress, the seedlings showed significant increases in fresh mass, leaf number and lateral root number, but only marginal increases in root length and leaf area. Despite these similarities, slight differences were observed in the metabolomes and proteomes of smoke water and GR24-treated seedlings, both with and without the addition of salt stress. Relatively few of the differentially expressed proteins could be identified with the instruments available. Changes in the metabolome indicated that photoassimilation and photosynthesis could be affected in response to smoke water and GR24 treatment. Our results suggest that smoke water and GR24 both promote growth under salt stress conditions in seedlings and we furthermore conclude that, although there are distinct overlaps between treatments, this is accomplished via slightly different mechanisms. / AFRIKAANSE OPSOMMING: Gedurende ‘n plant se lewe word omtrent alle prosesse deur die omgewing geaffekteer. Veranderinge in die omgewing word gevolg deur veranderinge in hormoon, metaboliet en protein vlakke. Plant groei stimulante affekteer hierdie vlakke om plant groei en -opbrengs na bo normalle vlakke te verhoog. In hierdie studie word die effek van twee groei stimulante, rook water verkry deur rook van plant materiaal deur water te borrel en ‘n sintetiese strigolaktoon, GR24, ondersoek op ‘n morfologiese, metaboliese en ‘n proteomiese vlak in Nicotiana benthamiana saailinge. ’n Studie is onderneem om die veranderinge as gevolg van die onderskeie groei stimulante te ondersoek in ‘n weefsel kultuur sisteem. Rook water het onder normale groei omstandighede vars en droeë massa, blaar aantal asook wortel en blaar lengte verhoog. Rook water het na sout behandeling (100 en 150 mM NaCl) steeds vars massa, wortel lengte, blaai aantal en laterale wortel aantal beduidend verhoog in vergelyking met die sout stres kontrole. Behandeling met GR24 het ook vars massa, wortel lengte, blaar aantal en grootte verhoog en onder sout stres met GR24 is ‘n beduidende vergroting opgemerk in vars massa, blaar grootte en laterale wortel aantal. Ongeag van die veranderinge in groei is klein verskille opgemerk in die metaboliet en protein studies. Net ‘n paar proteine kon positief geidentifiseer word met die apparaat beskikbaar. Verandering in die metaboloom wys na veranderinge in fotoassimilasie en fotosintese in reaksie tot rook water en GR24. Hierdie resultate lei tot die gevolgtrekking dat rook water en GR24 beide groei verbeter in saailing behandel met sout en ook dat alhoewel daar sekere ooreenkomste is tussen die reaksies as gevolg van die plant groei stimulante, dit wel geskiet deur geringe verskillende meganismes.

The stringent requirement for hemopoietic growth factors (HGF) in the induction of hemopoiesis in vitro has raised questions as to their possible role(s) in leukemogenesis. Several recent clinical studies have shown aberrant cell growth factor gene activation in patient derived leukemic cells. Assessment of growth factor activity is often based on in vitro bioactivity assays of conditioned media or body fluids. The specificity of this type of endpoint is, however, open to question due to the overlap in biological activities of many HGFs. In assessing the role of growth factor gene expression in a murine myeloid leukemia model I have used a sensitive RNA detection procedure coupled with a vector-probe system that enables the synthesis of uniformly labelled radioactive DNA probes to detect unambiguously the expression of particular growth factor genes. The Abelson murine leukemia virus (A-MuLV) derived myeloid transformants used in this study had previously been shown to produce a multi-lineage colony stimulating activity (CSA). While these A-MuLV transformants were shown to produce GM-CSF, it seemed likely that the multi-lineage CSA was due to another factor. In addition to confirming the expression of GM-CSF mRNA, I was able to show that the cells of all four A-MuLV transformed lines tested also expressed interleukin-3 mRNA. This finding was strongly corroborated by bio-activity data obtained using the CM from the A-MuLV myeloid transformants. Additional preliminary analysis by bioactivity assays have also shown the possible presence of interleukin-6 (IL-6) and a recently described pre-B cell factor suggesting perhaps a common mechanism underlying the activation of these various growth factor genes. / Medicine, Faculty of / Medical Genetics, Department of / Graduate

This research reported here was carried out to examine alternatives to antibiotic growth promoters as a result of their being banned in the animal feed industry. Four experiments were conducted to evaluate the efficacy of non-medicated feed additives as replacements for antibiotic growth promoters in broiler feeds. The additives used were enzymes (a new thermo-tolerant powder enzyme called TXAP, phytase, lipase and a new phytase enzyme derived from E. coli called phyzyme XP), organic acid (Acid Pak), prebiotic (Bio-Mos®) and probiotic (All-Lac XCL). Mashed maize-soya based feeds were used in all the experiments, which were conducted in litter-floor pens. The first experiment was a dose-response trial. Broilers in eight replicate pens of 50 males and 50 females were fed unsupplemented feeds and five additional feeds containing increasing levels of TXAP, from 0.5 to 2.5 g/kg to 42 d. The second experiment used enzyme TXAP with two different enzymes (phytase and lipase), individually or in combination. Six replicate pens of 50 males and 50 females were fed either unsupplemented feeds or one of six additional feeds treated with TXAP, lipase, phytase , a combination of TXAP and lipase, a combination of TXAP and phytase or a combination of all the three enzymes . This trial continued for 42 d. In the third experiment three types of TXAP (Lot 1, 2 and 3) were used, with fixed levels of xylanase and amylase but varying levels of protease activities (4000, 2000 and 1000 U/kg for Lot 1, 2 and 3, respectively) in combination with phyzyme XP for 35 d. The fourth experiment used mannan-oligosaccharide (Bio-Mos®), organic acid (Acid pak 2x), probiotic (All Lac XCL 5x), individually or in combination and an antibiotic growth promoter (Zinc bacitracin) for 42 d. The chickens in this experiment were challenged with Clostridium perfringens (CP) at 21, 22 and 23 d to determine the efficacy of these additives for replacing antibiotics in hindering the effects of CP on the villus surface area. The dose-response trial did not show any significant improvement in broiler performance with any level of inclusion of enzyme TXAP. The results from this study showed some beneficial effects with the use of enzyme TXAP when fed alone and at a young age. Its use when combined with other enzymes and at later stages of growth needs further investigation. Feed additives in experiment 4 prevented the negative effects of CP as the treated chickens did not have lesions on their villus surfaces. The conditions under which these trials were conducted appeared to be such that little benefit was derived from the use of any of the feed additives used. It is possible that under less-hygienic conditions such as those in commercial operations greater benefits from these additives may be realised. / Thesis (M.Sc.)-University of KwaZulu-Natal, Pietermaritzburg, 2006.