Variables for the accelerated ageing (AA) test, methods for reducing fungal contamination during the AA test, using the conductivity test as a vigour test, the effect of seed size on seed vigour and the relationship between laboratory test results and field perfonnance in selected Brassica spp were investigated. In the first experiment, three seed lots of turnip rape hybrid (B. rapa x campestris), turnip (B. campestris) and forage rape (B. napus); and seven seed lots of Asian rape (B. napus), six seed lots of Asian kale (B. oleraceae var. alboglabra L.) and five seed lots of choisum (B. rapa var. pekinensis) with germinations above 90% were aged at two different temperatures (41 and 42°C ± 0.3°C) and three ageing times (24, 48 and 72 ± 15 minutes). The second experiment was divided into three sections. In the first, the same seed lots and species were aged at one temperature (41°C) and time (72 h), but either 40 ml of saturated salts; KCl (83%RH), NaCl (76%RH), NaBr (55%RH); or distilled water (96%RH) were used as the ageing solutions. In the second, one turnip rape hyprid seed lot was aged at three temperatures (41, 42 and 45°C) and two times (72 and 96h), again using the three saturated salts and distilled water as ageing solutions. In the third, three turnip rape hybrid seed lots and three Asian kale seed lots were surface sterilised (1 % sodium hypochlorite) prior to ageing at one temperature (41°C) and time (72 h). In the third experiment, the same species and seed lots used in experiment one at their original seed moisture content (SMC) were tested for conductivity after soaking in deionised water for 4, 8, 12, 16, 20 and 24 h. They were then re-tested after the SMC had been adjusted to 8.5%. In the fourth experiment, three seed lots of forage rape and three seed lots of Asian kale were graded into three seed size categories; large (retained on a 2.0 mm screen), medium (retained on a 1.7 mm screen) and small (passed through a 1.7 mm screen). Graded seeds were then tested for standard germination, AA (41°C/48 h) and conductivity (measured at 16 and 24 h). In the final experiment, the relationships between laboratory tests for the six species (each consisting of three seed lots), field emergence from three sowings, and cold room emergence were evaluated. Both time and temperature influenced post-AA germination. Increasing the ageing period from 48 to 72 hours at 41°C, and 24 to 48 hours at 42°C resulted in decreased mean germination percentage for all species but not always clear separation of seed lots. While there were sometimes few differences between ageing at 41°C and 42°C, the former is preferred because it is already the temperature used for other species. For Asian rape, choisum and turnip, the previously recommended testing conditions of 41°C/72 h provided good seed lot separation, but for Asian kale and turnip rape hybrid, AA testing at 41°C/48 h provided better results. Seed moisture content after ageing ranged from 29-37% depending on species. Fungal growth on seeds during the ageing period appeared to reduce post-ageing germination in some seed lots . Substituting saturated salts for distilled water did not stress seed lots in the AA test, due to the lowered RH%, the exception being seed lots 1210 and 1296. For forage and Asian species, seed lot germination mostly remained above 90% when aged for 72 h at lowered RH%. Increasing the ageing duration from 72 to 96 hours resulted in some decreases in post-AA germination but no clear separation of seed lots. Surface sterilising the seeds prior to the AA test resulted in a lower incidence of contaminant fungi which was associated with a lower percentage of abnormal seedlings. The conductivity test was mostly able to identify vigour differences among forage and Asian vegetable brassica seed lots. Differences in conductivity readings were observed among seed lots in all species. Increasing the period of imbibition resulted in increased conductivity from most seed lots but radicle emergence occurred after 16-20 h of imbibition. Variation was observed in the time to reach 95% maximum of the imbibition curve for most species. Conductivity readings at 16 h would avoid possible influences of radicle emergence on results. Adjusting the SMC to 8.5% resulted in reduced variation in conductivity among replicates of seed lots, due to a reduction in imbibition damage. Seed size had a significant effect on both post-AA germination and conductivity results. In forage rape, large size seeds had higher post-AA germination cf. medium cf. small size seeds. In Asian kale, large size seeds had higher post-AA germination compared with small size seeds. For both forage rape and Asian kale, large size seeds had lower conductivity readings cf. small size seeds. The correlation analyses demonstrated significant relationships between AA testing and field emergence parameters (percentage emergence, emergence index and emergence rate). Significant relationships were also observed between conductivity testing and these field emergence parameters. Based on the correlation analysis, AA testing at 41°C/48 hand/or 42°C/48 h could be recommended to be used as an AA test for turnip and Asian rape; and 41°C/48 hand/or 41°C/72 h for Asian kale and choisum. Based on the correlation analysis, conductivity testing at 16 h can be used to predict the field emergence potential of forage and Asian vegetable seed lots. Vigour tests were consistently able to provide better indicators of field perfonnance than the standard germination test, although these relationships did vary with the different field sowings.

Title page, table of contents and abstract only. The complete thesis in print form is available from the University of Adelaide Library. / Transient salinity in soils is characterised by high concentrations of salts in the subsoil. Durum wheat (Triticum turgidum L. Var. durum) is less tolerant of transient salinity than locally developed bread wheat (Triticum aestivum) varieties, and this results in reliable durum production being restricted to relatively unaffected soils. Field trials were conducted to assess the relative impact of transient salinity, boron toxicity and bicarbonate on crop production and highlighted the importance of combining tolerance to all three subsoil constraints into varieties intended for widespread adoption; and if the area of durum production is to be expanded. The Na exclusion locus from the landrace Na49 was found to improve the adaptation of durum to sites affected by transient salinity and is now being intogressed into a wide range of breeding material. / http://proxy.library.adelaide.edu.au/login?url= http://library.adelaide.edu.au/cgi-bin/Pwebrecon.cgi?BBID=1152134 / Thesis (Ph.D.) -- University of Adelaide, School of Agriculture and Wine, 2005

Univ., Diss.--Frankfurt, 2004. / Literaturverz. S. 19 - 42.

Submitted by Edileide Reis (leyde-landy@hotmail.com) on 2013-04-17T18:50:47Z No. of bitstreams: 1 Tatiane Ribas.pdf: 926925 bytes, checksum: 4fc6dcf30b665136b9016a2cf19dc8a9 (MD5) / Approved for entry into archive by Rodrigo Meirelles(rodrigomei@ufba.br) on 2013-05-09T17:40:52Z (GMT) No. of bitstreams: 1 Tatiane Ribas.pdf: 926925 bytes, checksum: 4fc6dcf30b665136b9016a2cf19dc8a9 (MD5) / Made available in DSpace on 2013-05-09T17:40:52Z (GMT). No. of bitstreams: 1 Tatiane Ribas.pdf: 926925 bytes, checksum: 4fc6dcf30b665136b9016a2cf19dc8a9 (MD5) Previous issue date: 2011 / O presente trabalho aborda a questão da preocupação surgida em torno da manipulação do genoma humano especialmente no que tange às práticas de engenharia genética na reprodução assistida e decorrente necessidade de proteção do patrimônio genético humano para as futuras gerações. Nesse sentido analisa-se a evolução do conhecimento científico até as biotecnologias de modificação genética atentando-se para o afastamento entre a ciência e a ética por conta do paradigma dominante e a busca bioética por sua reaproximação. Avalia-se ademais a função dos princípios para servirem de guias ao agir humano em face das novas possibilidades de sua intervenção que não mais está adstrita à natureza alcançando o próprio homem. Discorre-se sobre a importância das declarações e documentos internacionais e também acerca da indispensabilidade do Direito enquanto ferramenta apta a regular as pesquisas e as aplicações biotecnológicas principalmente quando voltadas para o ser humano. A questão do tratamento jurídico pelo ordenamento brasileiro é abordada para se demonstrar o vácuo legislativo acerca das práticas de reprodução humana assistida e as possíveis decorrências dessa omissão bem como as limitações legais em torno das possibilidades de engenharia genética sobre a constituição genotípica do ser gerado mediante essas técnicas. Todo o trabalho tem como norte os princípios da dignidade da pessoa humana da sua vulnerabilidade enquanto condição e a ética da responsabilidade, com vistas para a proteção do direito fundamental ao patrimônio genético humano cujo titular é a Humanidade presente e futura. / Salvador

Genetically modified (GM) crops are commercially cultivated worldwide but there are concerns on their possible negative impacts on soil biodiversity. A glasshouse study was conducted to determine effects of Bt maize residues on soil microbial diversity. Residues of Bt maize (PAN 6Q-308B) and non-Bt maize (PAN 6Q-121) were incorporated into the soil and corresponding maize seeds planted. The treatments were replicated three times. Fertilizer and water application were similar for both treatments. Rhizosphere and bulk soil was destructively sampled from each treatment and analyzed for microbial community level physiological profiles using Biolog plates with 31 different carbon substrates. Absorbance in the Biolog plates was recorded after 72 h of incubation at 20oC. Arbuscular mycorrhizal fungi spore counts were also determined. Field studies were conducted at the University of Free State and University of Fort Hare Research Farms to determine the effects of growing Bt maize on soil microbial diversity. One Bt maize cultivar (PAN6Q-308B) and non-Bt maize (PAN6Q-121) were grown in a paired experiment at University of Free State farm, while two Bt maize (DKC61-25B and PAN6Q-321B) and their near-isogenic non-Bt maize lines (DKC61-24 and PAN6777) were grown in a randomized complete block design with three replicates. Fertilization, weed control and water application, were similar for both Bt maize cultivars and their non-Bt maize counterparts. Rhizosphere soil samples were collected by uprooting whole plants and collecting the soil attached to the roots. The samples were analysed for microbial diversity and for arbuscular mycorrhizae fungal spore counts. Principal component analysis showed that soil microbial diversity was affected more by sampling time whereas genetic modification had minimal effects. Presence of residues also increased the diversity of microorganisms. Mycorrhizal fungal spores were not affected by the presence of Bt maize residues. Growing Bt maize had no effect on the soil microbial diversity in the rhizosphere.

L’objectif de cette thèse est de développer une nouvelle souche de champignon filamenteux pour la production d’acide lactique. Pour répondre à cet objectif, nous avons tout d’abord d’exploré la biodiversité fongique à la recherche de champignons filamenteux capables de produire de l’acide lactique ou présentant de bonnes prédispositions pour la production d’acides organiques sans neutralisation du pH. Grâce à ce criblage, une souche sauvage d’Aspergillus brasiliensis a été sélectionnée et utilisée pour construire, grâce à l’ingénieure métabolique, les premières souches d’Aspergillus capables de produire de l’acide lactique à pH acide. Ces souches ont ensuite été caractérisées et les conditions de culture en fioles et fermenteurs volumes ont été étudiées. Cette étude des conditions de culture donne des résultats prometteurs et dévoile de nombreuses voies possibles pour continuer à améliorer la production d’acide lactique par ces organismes. / The objective of this thesis is to develop a new filamentous fungal strain for the production of lactic acid. To meet this goal, we first explored the fungal biodiversity in order to find filamentous fungi able to produce lactic acid or having good predispositions for the production of organic acids without pH neutralization. Through this screening, a wild type strain of Aspergillus brasiliensis was selected and used to construct, using the metabolic engineer, new strains capable of producing lactic acid at an acidic pH. These strains were then characterized and culture conditions in flasks and bioreactors were studied. The study of culture conditions shows promising results and reveals many possible ways to further improve the production of lactic acid by these organisms.

Les biotechnologies sont un outil puissant permettant d’emprunter les circuits biologiques pour produire des composés aux applications multiples (médecine, alimentation, industries…). Les cyanobactéries possèdent des propriétés génétiques et trophiques précieuses pour réduire les coûts et l’empreinte environnementale de ces procédés (photosynthèse, fixation du CO₂, sources d’azote assimilables...). Elles produisent aussi naturellement certaines molécules énergétiques comme le H₂ dont pourraient émerger de nouvelles filières propres de biocarburants. Cependant, une compréhension globale et approfondie de leur physiologie est nécessaire pour concevoir un châssis biologique performant à partir de ces organismes. Elles sont aisément manipulables génétiquement mais présentent une versatilité favorisant la fixation de mutations bénéfiques mais aussi délétères pour leur exploitation à grande échelle. Au cours de ma thèse, j’ai construit et étudié des mutants d’un régulateur de l’assimilation du CO₂ dont l’activation est liée à la photosynthèse. J’ai montré que l’activité du cycle de Calvin synchronise les flux du carbone et le statut rédox de Synechocystis et que sa dérégulation se répercute de manière pléiotropique sur son métabolisme. Plus spécifiquement, je me suis intéressé au déséquilibre carbone/azote dans cette espèce et à son métabolisme de l’urée qui présente un intérêt biotechnologique considérable. J’ai démontré que ce dernier était en compétition avec l’hydrogénase pour l’insertion du nickel dans leurs centres catalytiques respectifs. L’insuffisance de ce métal a permis de sélectionner des mutants de l’uréase tolérant une exposition prolongée à l’urée et conservant une forte capacité de production de H₂ en présence de ce substrat azoté. L’ensemble de ces résultats montre que le métabolisme de Synechocystis peut être détourné au profit de certains processus cellulaires. Les approches « omiques » permettent d’identifier globalement les réponses physiologiques induites ainsi que les leviers biologiques de compensation. Ces travaux sont discutés au regard des implications biotechnologiques de l’instabilité génétique et de la nécessité de renforcer notre compréhension de la plasticité métabolique et génomique des cyanobactéries. / Biotechnology is a powerful tool allowing exploitation of biological circuits to produce compounds with multiple uses (medicine, nutrition, industrial…). Cyanobacteria have valuable genetic and trophic properties which could reduce the costs and the environmental footprint of these processes (photosynthesis, CO₂ fixation, assimilation of diverse nitrogen sources…). They also naturally produce energetic molecules such as H₂ from which new and sustainable biofuels sectors may rise. However, a global and fine understanding of their physiology is required in order to design an efficient biological chassis with these organisms. They are genetically manipulable but also exhibit a strong versatility favoring fixation of mutations that can be either beneficial or harmful to their large-scale cultivation. Over the course of my PhD, I constructed and studied mutants of a CO₂ fixation regulator whose activation is linked to photosynthesis. I showed that the Calvin cycle activity synchronizes carbon fluxes and redox status in Synechocystis and that its deregulation affects the metabolism in a pleiotropic manner. I was specifically interested into the carbon/nitrogen balance in this species and its urea metabolism which is of prime interest in biotechnology. I demonstrated that the latter was in competition with the hydrogenase for the insertion of nickel into their respective catalytic centers. Scarcity of this metal leads to selection of mutants thriving upon prolonged exposure to urea that retained a high capacity of H₂ production in presence of this nitrogenic substrate. This work shows that the metabolism of Synechocystis can be altered in favor of other cellular processes. Omics approaches allow global identification of the physiological responses induced as well as the biological compensation mechanisms. These observations are discussed with regards to biotechnological implications of genetic instability and the need to strengthen our understanding of metabolic and genetic plasticity in cyanobacteria.

Poultry provide affordable animal protein products compared to other animal products in agricultural industry. The demand of organic food by world health organisation and call for discard of conventional laying cage production method led to this research study. The aim of the study was to determine how (4 x 4) full diallel crossbreeding of the Potchefstroom Koekoek (PK), Naked neck (NN), Lohmann Brown (LB) and White Leghorn (WL) had an effect on production performance, egg parameters, genetic and phenotypic characteristics of F1 crossbreed offspring. The study was conducted at the Agricultural Research Council (ARC), Livestock Production Improvement at the Irene Campus, which is situated about 25 km south of Pretoria. The (4 x 4) full diallel crossbreeding design used on four chicken breeds to produce four pure breeds, six crossbreeds and six reciprocal crosses. The total number of 352 chickens with16 treatments (2 cocks and 20 hens) used in phase 1 and 384 chickens 16 F1-treatments (3 cocks + 21 hens) used in phase 2. Data was analysed by full factorial analysis of variance (ANOVA), General Linear Model procedures and Scheffe post-hoc for multiple comparison of the means of different variable data. The outcome had shown that crossbreeding had an effect on the production performance, genetic and phenotypic characteristics. The performed F1 crossbreeds emerge from crossbreeding between the local dual-purpose PK and commercial LB chicken breeds. PKLB dominated on growth and production performance traits compared to other crossbreeds. All set null hypothesis differ significantly at (p < 0.05), the outcome of all five hypothesis of this study were rejected. In conclusion PKLB was the best performing F1 crossbreed, based on its best performance on growth, FCR, cost of rearing, productive, high quality safe eggshell, economic efficiency and consumer preference (brown eggshell and yolk colour). / Dikgogo di neelana ka dikumo tsa poroteine ya diphologolo go tshwantshanngwa le dikumo tsa diphologolo tse dingwe mo intasetering ya temo. Tlhokego ya dijo tse di bolang mo mekgatlhong ya boitekanelo ya lefatshe le pitso ya go latlha mekgwa ya kumo ya dikgetshe tsa go beela tsa tlwaelo di ne tsa isa kwa thutong ya patlisiso eno. Maikaelelo a thuto eno ke go tlhomamisa gore tsadiso ya kgabaganyo ya dilo tse pedi kgotsa go feta go tshwantshanya kgolagano ya mofuta wa dijene le tikologo tse di tletseng tsa (4 x 4) tsa Potchefstroom Koekoek (PK), Naked Neck (NN), Lohmann Brown (LB) le White Leghorn (WL) di na le ponalo mo tiragatsong ya kumo, diparametera tsa mae, le dijene le diponagalo tsa kgolagano ya mofuta wa dijene le tikologo tsa ditsadiso tsa kgabaganyo tsa ngwana wa F1. Thuto e ne ya diragadiwa kwa Agricultural Research Council (ARC) le Tokafatso ya Kumo ya Diruiwa kwa khempaseng ya Irene, e e agilweng bokana ka 25 km jwa borwa jwa Pretoria. Ditsadiso tsa kgabaganyo tsa dilo tse pedi kgotsa go feta go tshwantshanya kgolagano ya mofuta wa dijene le tikologo tse di tletseng tsa (4 x 4) di ne tsa dirisiwa mo mefuteng ya ditsadiso tsa dikgogo go ntsha mefuta ya ditsadiso e e tletseng e mene, ditsadiso tsa kgabaganyo tse thataro le dikgabaganyo tse di tshwanang tse thataro. Palo e e tletseng ya dikgogo tse di 352 ka ditiragatso di le 16 (mekoko e le 2 le dithole di le 20) di ne tsa dirisiwa mo letlhakoreng la 1 le dikgogo di le 384 ka ditiragatso tsa F1 di le 16 (mekoko e le 3 + dithole di le 21) di ne tsa dirisiwa mo letlhakoreng la 2. Data e ne ya tshetshereganngwa ka tshetshereganyo ya dintlha tse di tletseng tsa pharologantsho (ANOVA), dikgato tsa General Linear Model le tshwantshanyo ya bontsintsi ya morago (ANOVA), dikgato tsa General Linear Model le tshwantshanyo ya bontsintsi ya morago ga tiragalo ya Scheffe ka mekgwa ya data ya pharologantsho e e farologaneng. Ditlamorago di ne tsa bontsha gore ditsadiso tsa kgabaganyo di na le ponalo mo tiragatsong ya kumo, ga mmogo le diponagalo tsa dijene le setlhopha sa kgolagano ya mofuta wa dijene le tikologo. Go ne ga diriswa mefuta ya ditsadiso tsa kgabaganyo ya F1 tse di tlhagelelang go tswa mo ditsadisong tsa kgabaganyo magareng ga mefuta ya ditsadiso tsa dikgogo tsa PK tsa lebaka la gabedi la selegae le LB ya kgwebo. PKLB e ne ya fekeetsa metlhala ya tiragatso ya kgolo le kumo go tshwantshanngwa le mefuta ya ditsadiso tsa kgabaganyo tse dingwe. Setlhopha sotlhe sa dikakanyo tsa lefela se x farologana mo go bonagalang ka (p < 0.05) le ditlamorago tsa dikakanyo tse tlhano tse tsotlhe tsa thuto eno di ne tsa kganediwa. Kwa bokhutlong, PKLB e ne ya nna mofuta wa ditsadiso tsa F1 o o diragatsang go gaisa, go ikaegilwe ka tiragatso mabapi le kgolo, FCR, tshenyegelo ya go tsadisa, kumo, boleng jo bo kwa godimo jwa dikgapetla tsa mae tse di babalesegileng, bokgoni jwa ikonomi le boikgethelo jwa modirisi (dikgapetla tsa mae tse di tshetlha le mmala wa tlhae). / Agriculture and  Animal Health / Ph. D. (Agriculture)

My dissertation research examined the effect of the cultivation of insect-resistant Bacillus thuringiensis (Bt) maize on the soil environment with a goal of understanding how to obtain a balance between technological advancement and maintenance of a healthy soil ecosystem. Although Bt plants may help to reduce pesticide use, conferring benefits to farm workers and the environment, there are still unresolved questions about how the cultivation of Bt plants affects soil organisms. For this dissertation project, I used 14 different genotypes of Bt maize and non-Bt maize (Zea mays) to investigate the effects of transgenic Bt plants on the colonization ability, abundance, and diversity of symbiotic arbuscular mycorrhizal fungi (AMF) in the soil ecosystem over time. My greenhouse studies demonstrated that Bt maize plants exhibited reduced AMF colonization across multiple Bt genotypes and that effects were most pronounced when fertilizer levels were limited and spore density was high. In addition, I found that although differences in AMF colonization between Bt and non-Bt maize were difficult to detect in the field, spore density was reduced in Bt field plots after just one growing season. When I tested the effect of plot history on AMF and plant growth, I found that Bt and non-Bt maize plants had higher leaf chlorophyll content when grown in plots previously cultivated with the same maize line as the previous year, indicative of a positive feedback effect. I also examined potential mechanisms contributing to the reduced AMF colonization observed in Bt maize in greenhouse studies and determined that follow-up experiments should continue to investigate differences in root apoplastic invertase activity and root permeability in Bt and non-Bt maize. Future investigations would also benefit from examining potential differences in root exudate profiles and volatile organic compounds between Bt and non-Bt cultivars. Taken together, my dissertation results suggest that, while difficult to detect in the field, reductions in AMF colonization in Bt maize roots may be ecologically significant as they could lead to a decrease in the abundance of AMF propagules in the soil over time, potentially impacting soil structure and function in areas where Bt crop cultivation is high.

Indiana University-Purdue University Indianapolis (IUPUI) / The development of new methods to carry out gene transfer has many benefits to several fields, such as gene therapy, agriculture and animal health. The newly established lentiviral vector systems further increase the efficiency of gene transfer dramatically. Some studies have shown that lentiviral vector systems enhance efficiency over 10-fold higher than traditional pronuclear injection. However, the timing for lentiviral vector integration to occur remains unclear. Integrating in different stages of embryogenesis might lead to different integration patterns between tissues. Moreover, in our previous study we found that the vector copy number in transgenic sheep varied, some having one or more copies per cells while other animals having less than one copy per cell suggesting mosaicism. Here I hypothesized that injection of a lentiviral vector into a single cell embryo can lead to integration very early in embryogenesis but can also occur after several cell divisions. In this study, we focus on investigating integration sites in tissues developing from different germ layers as well as extraembryonic tissues to determine when integration occurs. In addition, we are also interested in insertional mutagenesis caused by viral sequence integration in or near gene regions. We utilize linear amplification-mediated polymerase chain reaction (LAM-PCR) and next- generation sequencing (NGS) technology to determine possible integration sites. In this study, we found the evidence based on a series of experiments to support my hypothesis, suggesting that integration event also happens after several cell divisions. For insertional mutagenesis analysis, the closest genes can be found according to integration sites, but they are likely too far away from the integration sites to be influenced. A well-annotated sheep genome database is needed for insertional mutagenesis analysis.