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A taxonomic study on Ischaemum of Taiwan has been carried out through the past three years, according to morphological characters including habit, culm, leaf, inflorescence, spikelet, flower and caryopsis. The results indicated that there are totally 5 species of the genus occurring in Taiwan, i. e. Ischaemum aristatum L. var. aristatum (including I. aristatum var. momiyamai (Honda) Hsu) , I. barbatum Retzius (including I. barbatum var. gibbum (Trin.) Ohwi), I. ciliare Retzius (including I. indicum (Houtt.) Merr.), I. rugosum Salisbury (including I. akonense Honda and I. rugosum var. segetum Hackel), and I. setaceum Honda. Because of no specimens available for examination in the herbariums of Taiwan, I. aristatum var. crassipes (Steud.) Yonekura, I. aureum (Hook. & Arn.), I. muticum L., and I. timorense Kunth are treated as doubtful species. In addition, the features of awn, compression and lower glume of spikelets are realized the diagnostic characters to distinguish the species. In this study, the detailed descriptions of and a key to the species and varieties are given. Moreover, the distribution and habitat of each species are also provided.

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This thesis is a serological investigation of actinomycetes as a preliminary to taxonomic study.

Ganoderma root rot disease has been reported world wide causing the death of affected hosts. The taxonomy of the genus Ganoderma is considered to be in disarray due to the use of basidiocarp morphological characters to differentiate the species which resulted in many synonyms, species complexes and possible misidentifications of species within the genus. The use of sexual compatibility tests and molecular techniques became powerful diagnostic tools to elucidate the taxonomy of Ganoderma species. Application of these techniques has resolved some of the taxonomic problems but the use of certain species names in the genus is still causing contention among taxonomists. The literature surrounding the taxonomy and techniques used in the taxonomy of the root rot fungus Ganoderma are considered in this thesis. It is clear that the taxonomy of Ganoderma is very difficult and it is still largely obscured by species complexes and incorrect species identifications. It is also evident that a single species concept will not aid in the identification of Ganoderma species. Rather, a combination of concepts based on morphology, mating tests and DNA sequence data should be used in elucidating the taxonomy of Ganoderma. Morphological characteristics as well as nucleotide sequence analysis of three gene regions; the internally transcribed spacer (ITS), the mitochondrial small subunit (mtSSU) and the intergenic spacer (IGS-1), were used to identify the causal agent of Ganoderma root rot of J. mimosifolia in the suburb of Brooklyn, Pretoria, South Africa. Morphological observations and DNA-based phylogenies revealed that all isolates collected from infected trees belong to a single species that reside in the G. lucidum sensu lato complex. Acacia mangium is a leguminous tree that is grown as an exotic plantation species in Indonesia. These economically important trees are threatened by Ganoderma root rot disease. This disease is considered to be the most important cause of losses in A. mangium plantations. Phylogenetic analysis of ITS sequence data showed that G. philippii is the primary agent of Ganoderma root rot in A. mangium in Sumatra, Indonesia. / Dissertation (MSc)--University of Pretoria, 2011. / Microbiology and Plant Pathology / Unrestricted

With the large-scale metagenome sequencing data produced currently, alignment-free metagenomic profiling approaches have demonstrated the effectiveness of Markov models in addressing the limitations of alignment-based techniques, particularly in handling unclassified reads. The development of POSMM (Python Optimized Standard Markov Model), employing SMM (Standard Markov Model) algorithm, initially showcased competitive performance when compared to tools such as Kraken2. However, when subjected to simulated damages present in ancient metagenomics data, shortcomings emerged, leading to false positives or misclassified sequences that compromised overall classification accuracy. To address this problem, we developed a segmental genome model (SGM) algorithm based on the generation of the ensemble of models representing distinct classes of DNA segments in a genome. SGM incorporated a recursive segmentation and clustering approach to segregate regions of distinct composition in a microbial genome. An ensemble of higher-order Markov models is trained on DNA clusters generated for each genome. A database of models of genomes, with each genome represented by multiple Markov models are then queried to infer the origin of reads from a metagenome. SGM was benchmarked using diverse synthetic metagenome datasets of varying composition, read lengths, and error profiles. The comparative assessment showed that SGM consistently outperformed SMM. SGM brings in significant advances in alignment-free profiling, offering a new promising avenue for metagenomic exploration through its integration in the next version of POSMM. Furthermore, leveraging the power of integration of alignment-free and alignment-based approaches and highlighting the versatility and practicality of these methods in addressing critical public health challenges, we developed a statistical analysis and machine learning pipeline to identify candidate microbes associated with COVID-19. This involved a meta-analysis of the whole genome sequencing data of COVID-19 patients' samples and its predictive modeling to discern the distinctive microbial features. We improve and explore alignment-free metagenome profiling to raise the bar in metagenome profiling in complex real-world samples.

Research has shown that children categorize words in terms of taxonomic and slot-filler strategies. Monolingual children were thought to shift from a slot-filler to taxonomic strategy between the age of five and eight. The aim of this study is to analyze the way Mandarin-English bilingual children organize their lexical-semantic system through the use of a category-generation task that investigate taxonomic and slot-filler organizational strategies in each language. There were 53 Mandarin-English bilingual participants (between 4 and 7 years of age) included in this study. Participants were asked to name as many items as they could think of in slot-filler and taxonomic conditions in English and Mandarin. The results indicate greater performance in English than Mandarin in children who were five years or older. Four-year-old bilingual children produced comparable number of items in both slot-fill and taxonomic condition, but the five-, six-, and seven-year-old bilingual children showed greater performance in the taxonomic condition. Children performed better for the animal than the clothes category, and better for the clothes than the food category. These findings, while largely consistent with existing literature, suggest that the slot-filler to taxonomic shift may take place at an earlier age compared to monolingual children. / text