"November 2002" / Includes bibliographical references (leaves 128-153) / xviii, 153 leaves : ill. (some col.) ; 30 cm. / Title page, contents and abstract only. The complete thesis in print form is available from the University Library. / Thesis (Ph.D.)--University of Adelaide, Dept. of Soil and Water, 2002

Bibliography: leaves 138-160. The 152 species of mycorrhizal fungi can be difficult to identify and quantify because the taxonomy of these fungi is based on the description of spores, which is time consuming, requires considerable expertise and cannot be assumed to reflect the situation within the root. Few attempts have been made to identify the species which are present in roots. Several approaches have been identified in previous work and the development of sensitive molecular methods for identification and quantification of two species of arbuscular mycorrhizal (AM) fungi are described in this study. Mycorrhizal fungal communities were sampled in both natural and agricultural ecosystems at two sites in South Australia. The combination of spore identification from trap culture and field-collected soil promises to be an effective means to study diversity of AM fungi in a particular system. PCR primers for Glomus mosseae and Gigaspora margarita were designed from the internal transcribed spacer (ITS) sequences of field-collected spores, with the aim of providing tools for field diagnosis.

Graduation date: 1991

No description available.

Bibliography: leaves 138-160. / xii, 160 leaves : ill. ; 30 cm. / Title page, contents and abstract only. The complete thesis in print form is available from the University Library. / The 152 species of mycorrhizal fungi can be difficult to identify and quantify because the taxonomy of these fungi is based on the description of spores, which is time consuming, requires considerable expertise and cannot be assumed to reflect the situation within the root. Few attempts have been made to identify the species which are present in roots. Several approaches have been identified in previous work and the development of sensitive molecular methods for identification and quantification of two species of arbuscular mycorrhizal (AM) fungi are described in this study. Mycorrhizal fungal communities were sampled in both natural and agricultural ecosystems at two sites in South Australia. The combination of spore identification from trap culture and field-collected soil promises to be an effective means to study diversity of AM fungi in a particular system. PCR primers for Glomus mosseae and Gigaspora margarita were designed from the internal transcribed spacer (ITS) sequences of field-collected spores, with the aim of providing tools for field diagnosis. / Thesis (Ph.D.)--University of Adelaide, Dept. of Soil and Water, 2000?

Bibliography: leaves 138-160. / xii, 160 leaves : ill. ; 30 cm. / Title page, contents and abstract only. The complete thesis in print form is available from the University Library. / The 152 species of mycorrhizal fungi can be difficult to identify and quantify because the taxonomy of these fungi is based on the description of spores, which is time consuming, requires considerable expertise and cannot be assumed to reflect the situation within the root. Few attempts have been made to identify the species which are present in roots. Several approaches have been identified in previous work and the development of sensitive molecular methods for identification and quantification of two species of arbuscular mycorrhizal (AM) fungi are described in this study. Mycorrhizal fungal communities were sampled in both natural and agricultural ecosystems at two sites in South Australia. The combination of spore identification from trap culture and field-collected soil promises to be an effective means to study diversity of AM fungi in a particular system. PCR primers for Glomus mosseae and Gigaspora margarita were designed from the internal transcribed spacer (ITS) sequences of field-collected spores, with the aim of providing tools for field diagnosis. / Thesis (Ph.D.)--University of Adelaide, Dept. of Soil and Water, 2000?

The expression of a mammalian ras gene analog was previously found by Reymond et al. to be developmentally regulated in Dictyostelium discoideum using Northern analysis of strain AX-3 RNA (1984, Cell 39;141) and by Pawson et al. using specific immunoprecipitation of in vivo synthesized proteins from strain V12M2 (1985, Mol. Cell Biol. 5;33). Due to differences in the results of the two studies, it was decided to further examine ras expression by applying both protein and RNA techniques to a single strain of D.discoideum, V12M2. RNA samples from strain V12M2 cells at different stages of development were analyzed using Northern blotting. The same RNAs were translated in vitro, and the ras proteins synthesized were immunoprecipitated and analysed by polyacrylamide gel electrophoresis. In agreement with the findings of Reymond et al. (1984, Cell 39;141), Northern analysis with the cDNA ras probe revealed that the highest levels of the 1.2 and 0.9 kb ras mRNAs were present in the total RNA of V12M2 cells at the pseudoplasmodial stage of development, and very little ras mRNA was present in early developing cells. In contrast to the Northern analysis the greatest amount of ras protein was in vitro translated from the RNA of vegetative and 2 hour cells. Hence this work confirms in a single strain of Dictyostelium that the greatest amount of ras protein is synthesized at those developmental stages that contained the lowest levels of mRNA detectable by the cDNA probe. Possible reasons for this phenomena are discussed. In vitro RNA translation was also used to study the relationship between the two ras proteins of 23 and 24 kd. The proteins did not appear to be derived from one another by degradation or by post-translational modification. This result suggested that the two ras proteins of strain V12M2 must be derived from two different mRNAs. High stringency Southern blots of AX-3 DNA showed the expected restriction fragments detected by Reymond et al. (1984, Cell 39;141) . Low stringency blots showed three faint additional restriction fragments in Eco RI digests of AX-3 DNA. No additional restriction fragments were generated by an Eco RI-Bg1 II digest, but two of the three faint bands were smaller. This suggested that at least two of the Eco RI ras fragments are non-contiguous, and hence two to three ras genes may be present in addition to the one characterized by Reymond et al. (1984, Cell 39;141). All Northern and Southern bolts were probed with antisense RNA probes in order to gain greater sensitivity of detection as described by Cox et al. (1984, Dev. Biol. 101;485). / Science, Faculty of / Microbiology and Immunology, Department of / Graduate

No description available.

Not available / text

Systems biology studies the complex interactions between components of biological systems. One major goal of systems biology is to reconstruct the network of interactions between genes in response to normal and perturbed conditions. In order to accomplish this goal, large-scale data are needed. Accordingly, diverse powerful and high-throughput methods must be developed for this purpose. We have developed novel high-throughput technologies focusing on cellular phenotype profiling and now provide additional genome-scale analysis of gene and protein function. Few high-throughput methods can perform large-scale and high-throughput cellular phenotype profiling. However, analyzing gene expression patterns and protein behaviors in their cellular context will provide insights into important aspects of gene function. To complement current genomic approaches, we developed two technologies, the spotted cell microarray (cell chip) and the yeast spheroplast microarray, which allow high-throughput and highly-parallel cellular phenotype profiling including cell morphology and protein localization. These methods are based on printing collections of cells, combined with automated high-throughput microscopy, allowing systematic cellular phenotypic characterization. We used spotted cell microarrays to identify 15 new genes involved in the response of yeast to mating pheromone, 80 proteins associated with shmoo-tip 'localizome' upon pheromone stimulation and 5 genes involved in regulating the localization pattern of a group II intron encoded reverse transcriptase, LtrA, in Escherichia coli. Furthermore, in addition to morphology assays, yeast spheroplast microarrays were built for high-throughput immunofluorescence microscopy, allowing large-scale protein and RNA localization studies. In order to identify additional cell cycle genes, especially those difficult to identify in loss-of-function studies, we performed a genome-scale screen to identify yeast genes with overexpression-induced defects in cell cycle progression. After measuring the fraction of cells in G1 and G2/M phases of the cell cycle via high-throughput flow cytometry for each of ~5,800 ORFs and performing the validation and secondary assays, we observed that overexpression of 108 genes leads to reproducible and significant delay in the G1 or G2/M phase. Of 108 genes, 82 are newly implicated in the cell cycle and are likely to affect cell cycle progression via a gain-of-function mechanism. The G2/M category consists of 87 genes that showed dramatic enrichment in the regulation of mitotic cell cycle and related biological processes. YPR015C and SHE1 in the G2/M category were further characterized for their roles in cell cycle progression. We found that the G2/M delay caused by the overexpression of YPR015C and SHE1 likely results from the malfunction of spindle and chromosome segregation, which was supported by the observations of highly elevated population of large-budded cells in the pre-M phase, super-sensitivity to nocodazole, and high chromosome loss rates in these two overexpression strains. While the genes in the G2/M category were strongly enriched for cell cycle associated functions, no pathway was significantly enriched in the G1 category that is composed of 21 genes. However, the strongest enrichment for the G1 category consists of the genes involved in negative regulation of transcription. For instance, the overexpression of SKO1, a transcription repressor, resulted in strong cell cycle delay at G1 phase. Moreover, we found that the overexpression of SKO1 results in cell morphology changes that resembles mating yeast cells (shmoos) and activates the mating pheromone response pathway, thus explaining the G1 cell cycle arrest phenotype of SKO1 ORF strains.