Toxic/mutagenic potentials of Gambierdiscus toxicus (GT) and Prorocentrum lima (PL) methanol extracts (CME) were determined using brine shrimp (Artemia salina), mouse, chicken embryo and Salmonella microsomal assays. PL-CME and GT-CME were toxic to shrimp and mice. Isolation and separation were accomplished using ether/water, hexane/methanol partition and butanol extraction. Toxic fractions were purified using column and thin layer chromatography (TLC). GT-CME showed low levels of mutagenic potential. For GT isolated fractions and PL-CME, no mutagenic effects were observed. Both CMEs showed embryotoxicity, with no teratogenic effects. Ether/methanol and water/butanol fractions showed shrimp toxicity. These fractions were purified by treatment with warm/cold acetone. Acetone insoluble precipitates were obtained. Ether soluble acetone filtrate (ESAF) and butanol soluble acetone precipitate (BSAP) showed shrimp and mouse toxicity. GT-BSAP produced temperature depression in mice. Three toxic isolates were obtained from PL-ESAF, four from GT-ESAF and one from both BSAPs columns. TLC preparative plates showed at least 12 toxic isolates for PL-ESAF, 8 for GT-ESAF and 4 for GT-BSAP.

by To Siu-wing. / Thesis (M.Phil.)--Chinese University of Hong Kong, 1993. / Includes bibliographical references (leaves 182-195). / ACKNOWLEDGEMENTS --- p.VI / ABSTRACT --- p.VII / LIST OF TABLES --- p.IX / LIST OF FIGURES --- p.XI / ABBREVIATIONS --- p.XVII / Chapter PART I --- GENERAL ASPECTS / Chapter CHAPTER 1 --- GENERAL INTRODUCTION --- p.1 / Chapter CHAPTER 2 --- LITERATURE REVIEW / Chapter 2.1. --- History of fungal protoplast fusion / Chapter 2.1.1. --- Fungal protoplast preparation technique --- p.4 / Chapter 2.1.2. --- Application of fungal protoplasts --- p.5 / Chapter 2.2. --- Protoplast fusion by polyethene glycol (PEG) --- p.9 / Chapter 2.3. --- Incompatibility system in fungi --- p.10 / Chapter 2.4. --- Characterization of fusion products by genetic markers --- p.12 / Chapter PART II --- OPTIMIZATION OF PROTOPLAST RELEASE AND PROTOPLAST FUSION STUDIES / Chapter CHAPTER 3 --- PROTOPLAST ISOLATION OF Pleurotus florida AND Schizophyllum commune / Chapter 3.1. --- Introduction --- p.14 / Chapter 3.2. --- Materials and methods / Chapter 3.2.1. --- Strains and culture media --- p.14 / Chapter 3.2.2. --- Protoplast isolation in different types and concentrations of lytic enzyme --- p.15 / Chapter 3.2.3. --- Protoplast isolation using mycelium with different culture ages --- p.17 / Chapter 3.2.4. --- Protoplast isolation in different types and concentrations of osmotic stabilizers --- p.17 / Chapter 3.2.5. --- Collection of protoplast by centrifugation --- p.18 / Chapter 3.3. --- Results / Chapter 3.3.1. --- Effect of type and concentration of lytic enzyme --- p.19 / Chapter 3.3.2. --- Efficiency of protoplast isolation from mycelia with different culture ages --- p.25 / Chapter 3.3.3. --- Effect of types and concentrations of osmotic stabilizers --- p.28 / Chapter 3.3.4. --- Collecting efficiency of protoplast by centrifugation --- p.31 / Chapter 3.4. --- Discussion / Chapter 3.4.1. --- Choice of lytic enzyme system and time for enzyme digestion --- p.33 / Chapter 3.4.2. --- Culture age for maximum protoplast yield --- p.34 / Chapter 3.4.3. --- Choice of concentration and type of osmotic stabilizers --- p.35 / Chapter CHAPTER 4 --- PROTOPLAST FUSION OF Pleurotus florida AND Schizophyllum commune / Chapter 4.1. --- Introduction --- p.38 / Chapter 4.2. --- Materials and methods / Chapter 4.2.1. --- Protoplast formation and size of protoplasts --- p.39 / Chapter 4.2.2. --- Fluorescent staining of protoplasts' nuclei --- p.39 / Chapter 4.2.3. --- Stability of the genetics markers / Chapter 4.2.3.1. --- Preparation of media for checking the presence of genetics markers --- p.40 / Chapter 4.2.3.2. --- Determining the presence of auxotrophic as well as drug resistance markers --- p.42 / Chapter 4.2.4. --- Regeneration of mycelium from protoplast --- p.42 / Chapter 4.2.5. --- Protoplast fusion and screening of fusion products --- p.45 / Chapter 4.3. --- Results / Chapter 4.3.1. --- Size of protoplasts ofPf67 and Scl7 --- p.48 / Chapter 4.3.2. --- Proportion of protoplasts bearing nucleus --- p.48 / Chapter 4.3.3. --- Protoplast regeneration in regeneration medium / Chapter 4.3.3.1. --- Protoplasts regeneration morphologies --- p.52 / Chapter 4.3.3.2. --- Regeneration frequencies and back mutation frequencies of Pf67 and Scl7 protoplasts --- p.58 / Chapter 4.3.4. --- Effect of PEG fusion treatment on auxotrophic and drug resistance markers of Pf67 and Scl7 --- p.60 / Chapter 4.3.5. --- Fusion products obtained from screening process --- p.61 / Chapter 4.4. --- Discussion / Chapter 4.4.1. --- Effect of protoplast isolation and PEG treatment on the two fusion parents --- p.63 / Chapter 4.4.2. --- Structural heterogeneity of protoplasts --- p.64 / Chapter 4.4.3. --- Polymorphic nature of protoplast regeneration --- p.67 / Chapter 4.4.4. --- Protoplast fusion frequence --- p.67 / Chapter PART III --- ANALYSIS OF FUSION PARENTS AND FUSION PRODUCTS / Chapter CHAPTER 5 --- MORPHOLOGICAL AND CYTOLOGICAL STUDIES / Chapter 5.1. --- Introduction --- p.69 / Chapter 5.2. --- Materials and methods / Chapter 5.2.1. --- Strains --- p.69 / Chapter 5.2.2. --- Study on colonial and mycelial morphology --- p.70 / Chapter 5.2.3. --- Fluorescent staining of mycelial nuclei with DAPI --- p.70 / Chapter 5.2.4. --- Study on fruit body and basidial morphology / Chapter 5.2.4.1. --- Fruiting on agar plate --- p.71 / Chapter 5.2.4.2. --- Scanning electron microscopic examination --- p.73 / Chapter 5.3. --- Results / Chapter 5.3.1. --- Variation of colonial morphology --- p.74 / Chapter 5.3.2. --- Morphologies and the number of nuclei in the mycelial cells of fusion parents and fusion products --- p.76 / Chapter 5.3.3. --- Fruit body morphology --- p.82 / Chapter 5.3.4. --- Basidial morphology --- p.84 / Chapter 5.4. --- Discussion --- p.87 / Chapter CHAPTER 6 --- PHYSIOLOGICAL STUDIES OF FUSION PARENTS AS WELL AS FUSION PRODUCTS BY INVESTIGATING THE GROWTH RESPONSES TO DRUGS / Chapter 6.1. --- Introduction --- p.90 / Chapter 6.2. --- Materials and methods / Chapter 6.2.1. --- Strains and media --- p.96 / Chapter 6.2.2. --- Growth responses of the strains to different concentrations of drugs --- p.97 / Chapter 6.3. --- Results / Chapter 6.3.1. --- Comparison of growth pattern as well as growth rate between fusion parents and fusion regenerants --- p.98 / Chapter 6.3.2. --- Growth responses of fusion parents and fusion products on complete medium --- p.105 / Chapter 6.3.3. --- Growth responses of fusion parents and fusion regenerants on complete medium with acriflavin --- p.108 / Chapter 6.3.4. --- Growth responses of fusion parents and fusion products on complete medium with guaiacol --- p.111 / Chapter 6.4. --- Discussion / Chapter 6.4.1. --- General considerations on experimental design --- p.115 / Chapter 6.4.2. --- Growth responses of protoplast regenerants of either fusion parents --- p.116 / Chapter 6.4.3. --- Growth responses on complete medium without fungitoxic drug --- p.117 / Chapter 6.4.4. --- Growth responses on the acriflavin agar medium --- p.118 / Chapter 6.4.5. --- Growth responses on guaiacol agar medium --- p.119 / Chapter 6.4.6. --- Summary --- p.120 / Chapter CHAPTER 7 --- GENETICAL STUDIES / Chapter 7.1. --- Introduction --- p.121 / Chapter 7.2. --- Materials and methods / Chapter 7.2.1. --- Segregation tests of auxotrophic and drug resistance markers in progeny of dikaryotic fusion product --- p.127 / Chapter 7.2.2. --- Complementation test of fusion products as well as the spore germinants of dikaryotic fusion product PS1 --- p.129 / Chapter 7.2.3. --- Recovery of the individual nuclear type of dikaryotic fusion product PS1 --- p.130 / Chapter 7.2.4. --- Genomic fingerprinting / Chapter 7.2.4.1. --- Strains and culture medium --- p.133 / Chapter 7.2.4.2. --- Genomic DNA preparation by cesium chloride (CsCl) method --- p.135 / Chapter 7.2.4.3. --- Genomic DNA preparation by chloroform :TE saturated phenol method --- p.136 / Chapter 7.2.4.4. --- Qualitative analysis of genomic DNA --- p.137 / Chapter 7.2.4.5. --- Quantitative analysis of genomic DNA --- p.137 / Chapter 7.2.4.6. --- DNA amplification by arbitrarily primed -polymerase chain reaction --- p.138 / Chapter 7.3. --- Results / Chapter 7.3.1. --- Progeny analysis and determination of auxotrophic as well as drug resistance markers --- p.140 / Chapter 7.3.2. --- Complementation tests of the fusion products as well as the spore germinants of dikaryotic fusion product PS1 --- p.143 / Chapter 7.3.3. --- Monokaryotic protoplast regenerants of dikaryotic fusion product PS1 --- p.147 / Chapter 7.3.4. --- Studies on extraction of undigested genomic DNA --- p.148 / Chapter 7.3.5. --- Genomic fingerprinting by AP-PCR --- p.155 / Chapter 7.4. --- Discussion / Chapter 7.4.1. --- Genomic DNA extraction --- p.161 / Chapter 7.4.2. --- Recovery of the individual nuclear type of dikaryotic fusion product PS1 --- p.165 / Chapter 7.4.3. --- Genomic changes in fusion products --- p.167 / Chapter 7.4.4. --- Progeny analysis and determination of auxotrophic as well as drug resistance markers --- p.171 / Chapter PART IV --- SUMMING-UP / Chapter CHAPTER 8 --- GENERAL SUMMARY AND CONCLUSION REMARKS / Chapter 8.1. --- General summary --- p.176 / Chapter 8.2. --- Conclusion remarks and future studies --- p.179 / REFERENCES --- p.182 / APPENDIX A SOLUTIONS

Thesis (M. Ph.)--Chinese University of Hong Kong. / Bibliography: l. 73-78.

No description available.

No description available.

Thesis (M.D.)--University of Adelaide, Dept. of Pathology, 1988. / Previous publications comprise main text of thesis. Includes bibliographical references.

Thesis (Ph. D.)--University of Hong Kong, 2000. / Includes bibliographical references (leaves 193-206).

Thesis (Ph.D.) - University of Queensland, 2004. / Includes bibliography.

Thesis (Ph. D.)--Columbia University, 1924. / Biographical note. "Chronological bibliography": p. 24.

M.B.A / Although current legislation does not require companies to have Environmental Management Systems (EMS), the time is approaching where certified companies world-wide may well be offered preferential treatment by their governments (Diller, 1997: 36 - 39). South African companies are also realising that the environment is important (AFT Newsletter, 1997: 1). It seems likely, therefore, that many foreign trading partners will require international registration from their import manufacturers (Kumar & Kumar, 1997). Impala Platinum Limited produces various metals at its Base Metal Refinery (BMR) in Springs, Gauteng Province, South Africa. In its pursuit ofthe extraction and refining of these metals, the company makes use of staff drawn mostly from the adjacent residential area of Springs. This area also borders on a World Wildlife-proclaimed wetland, known as the Blesbokspruit. The company has thought it prudent to research the need to implement an EMS at the Springs site (Reynolds, 1998; Skelton, 1998b), for the following reasons: • to ensure competitive advantage by pre-empting customer requirements with regard to responsible environmental management; • to provide a safe, healthy working environment for the company's staff; • to provide a safe, healthy environment for residents living in the close proximity of the site;..