published_or_final_version / abstract / Ecology and Biodiversity / Master / Master of Philosophy

Studies in a number of human tissues have revealed that the activities of mitochondrial respiratory chain enzyme complexes decline during the aging process. Other studies have suggested that aging increases the frequency of mitochondrial DNA (mtDNA) mutation and leads to the accumulation of mutant mtDNA species, mainly those with large deletions and point mutations. Although the mitochondrial theory of aging may be more applicable to post mitotic tissues, abnormalities of mtDNA have also been reported in tissues which retain a mitotic capacity. Fresh tissues from elderly patients are difficult to obtain and only a limited number of studies on biochemical examination of respiratory chain enzyme complex activities have been carried out. Prostate tissue is readily available in elderly male subjects because of the high prevalence of benign prostatic hypertrophy in this sub-group of the population, and endoscopic surgery is routinely performed for excision of the diseased prostate. In this study, mitochondrial respiratory function and the mtDNA mutations in prostate tissues of elderly patients (aged from 56 to 92) were studied in 24 subjects. This included the measurement of the activities of the respiratory chain enzyme complexes and screening for mitochondrial point mutations and deletions at sites commonly affected in neurodegenerative diseases. (For complete summary open document)

published_or_final_version / abstract / Biochemistry / Master / Master of Philosophy

Suen, Wai Chiu. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2009. / Includes bibliographical references (leaves 117-128). / Abstract also in Chinese. / ACKNOWLEDGEMENTS --- p.ii / LIST OF ABBREVIATIONS --- p.iii / ABSTRACT --- p.v / 摘要 --- p.vii / LIST OF PUBLICATIONS --- p.viii / TABLE OF CONTENTS --- p.ix / Chapter CHAPTER 1. --- INTRODUCTION --- p.1 / Chapter 1.1. --- Nature of Telomeres / Chapter 1.1.1. --- Telomere structure --- p.1 / Chapter 1.1.2. --- Importance of telomeres --- p.2 / Chapter 1.1.3. --- Telomere length attrition during replicative senescence --- p.3 / Chapter 1.1.4. --- Telomere length maintenance --- p.6 / Chapter 1.1.5. --- "Oxidative stress, inflammatory process and telomere length" --- p.7 / Chapter 1.1.6. --- Telomere attrition rate --- p.8 / Chapter 1.2. --- "Age, Gender and Telomere Length" / Chapter 1.2.1. --- Age and telomere length --- p.10 / Chapter 1.2.2. --- Gender difference of telomere length --- p.10 / Chapter 1.3. --- Health Status and Telomere Length --- p.13 / Chapter 1.3.1. --- Coronary heart diseases --- p.13 / Chapter 1.3.2. --- Cancers --- p.14 / Chapter 1.3.3. --- Infections and chronic inflammation --- p.15 / Chapter 1.3.4. --- Bone mineral density --- p.16 / Chapter 1.3.5. --- Neurodegenerative diseases --- p.17 / Chapter 1.3.6. --- Frailty and mortality --- p.19 / Chapter 1.4. --- "Lifestyles, Environment and Telomere Length" --- p.21 / Chapter 1.4.1. --- Obesity --- p.21 / Chapter 1.4.2. --- Smoking --- p.22 / Chapter 1.4.3. --- Physical activity --- p.23 / Chapter 1.4.4. --- Diet --- p.23 / Chapter 1.4.5. --- Psychological stress --- p.24 / Chapter 1.4.6. --- Socioeconomic status --- p.24 / Chapter 1.5. --- Methods of Measuring Telomere Length --- p.27 / Chapter 1.6. --- Aims and Hypotheses of the Study --- p.31 / Chapter 1.6.1. --- Aims --- p.31 / Chapter 1.6.2. --- Hypotheses --- p.31 / Chapter CHAPTER 2. --- SUBJECTS AND METHODS --- p.33 / Chapter 2.1. --- Subjects Recruitment --- p.34 / Chapter 2.2. --- Interview --- p.34 / Chapter 2.3. --- Anthropometry --- p.35 / Chapter 2.4. --- DNA Extraction and Storage --- p.35 / Chapter 2.5. --- Telomere Length Measurement --- p.37 / Chapter 2.5.1. --- Terminal restriction fragment analysis --- p.37 / Chapter 2.5.2. --- Quantitative real-time PCR --- p.39 / Chapter 2.6. --- Self-perceived Health --- p.46 / Chapter 2.7. --- Medical History --- p.46 / Chapter 2.8. --- Bone Mineral Density --- p.47 / Chapter 2.9. --- Frailty Index --- p.47 / Chapter 2.10. --- Mortality Rate --- p.50 / Chapter 2.11. --- Smoking --- p.50 / Chapter 2.12. --- Physical Activity --- p.51 / Chapter 2.13. --- Dietary Intakes --- p.51 / Chapter 2.15. --- Socioeconomic Status --- p.52 / Chapter 2.16. --- Statistical Analysis --- p.53 / Chapter CHAPTER 3. --- RESULTS AND DISCUSSIONS --- p.55 / Chapter 3.1. --- Demographics --- p.55 / Chapter 3.2. --- Telomere Length Distribution --- p.64 / Chapter 3.2.1. --- Age and telomere length --- p.64 / Chapter 3.2.2. --- Gender and telomere length --- p.68 / Chapter 3.3. --- Health Status and Telomere Length --- p.71 / Chapter 3.3.1. --- Self-perceived health --- p.71 / Chapter 3.3.2 --- History of diseases --- p.74 / Chapter 3.3.3. --- Bone mineral density --- p.80 / Chapter 3.3.4. --- Frailty index --- p.86 / Chapter 3.3.5. --- Mortality rate --- p.91 / Chapter 3.4. --- "Lifestyles, Environment and Telomere Length" --- p.94 / Chapter 3.4.1. --- Smoking --- p.94 / Chapter 3.4.2. --- Physical activity --- p.99 / Chapter 3.4.3. --- Diet --- p.104 / Chapter 3.4.4. --- Socioeconomic status --- p.109 / Chapter CHAPTER 4. --- CONCLUSIONS --- p.115 / Chapter 4.1. --- General conclusions --- p.115 / Chapter 4.2 --- The Significance of telomere length in the elderly --- p.115 / Chapter 4.3. --- Future Works and Prospect --- p.116 / References --- p.117

published_or_final_version / Biochemistry / Doctoral / Doctor of Philosophy

'The rate of living' hypothesis of aging speculates that the metabolic rate of a species ultimately determines its life expectancy. Using the nematode worm Caenorhabditis elegans as model system, mutation in twp-1 (t&barbelow;ime w&barbelow;arp) gene was found to significantly delay biological timing and remarkably increase mean and maximum life span. The rate of living in twp-1 is dramatically delayed in all the biological processes we tested, including rates of rhythmic adult behaviors, development, and reproduction. Oxygen consumption, which indicates metabolic rate of an organism, is reduced to approximately two-fold in twp-1 mutant. According to my study, twp-1 and dauer genes, daf-2 and daf-16, interact to determine biological timing and adult life span. twp-1 mutation prolongs life span in a way that is at least partially different from dauer formation mutants, whose longevity might due to their high resistance to stresses, especially oxidative stress. twp-1 gene is cloned and found to encode iron-sulfur protein (ISP) in complex III, which is the major site of mitochondrial superoxide radical production, of the mitochondrial respiratory chain. This suggests that twp-1 may live long because they produce less reactive oxygen species (ROS), and thus, result in less oxidative damage. mts-1 (mitochondrial twp-1 suppressor) mutation can fully or partially rescue most of the biological timing in twp-1 mutant, including both developmental and behavioral rates, but except life span. mts-1 encodes another subunit of complex III, cytochrome b, which normally interact with ISP during function. mts-1 might somehow restore the activity of complex III, and consequently, accelerate the rate of living. Paraquat, a herbicide that induces the formation of superoxide, was used to provide an acute oxidative stress to animals. twp-1; mts-1 was found to be highly resistant to paraquat, indicating that twp-1 animals are well capable of coping with oxidative stress. According to o

The aim of this thesis was to investigate the possibility of using buccal cells derived from a multi layered epithelial tissue from the oral mucosa as a model to identify potential biomarkers of genomic instability in relation to normal ageing and premature ageing syndromes such as AD and DS. A buccal micronucleus cytome assay was developed and used to investigate biomarkers for DNA damage, cell proliferation and cell death in healthy young, healthy old and young Down’s syndrome cohorts. Cells with micronuclei, karyorrhectic cells, condensed chromatin cells and basal cells increased significantly with normal ageing (P<0.0001). Cells with micronuclei and binucleated cells increased (P<0.0001) and condensed chromatin, karyorrhectic, karyolytic and pyknotic cells decreased (P<0.002) significantly in Down’s syndrome relative to young controls. The buccal micronucleus cytome assay was used to measure ratios of buccal cell populations and micronuclei in clinically diagnosed Alzheimer’s patients compared to age and gender matched controls. Frequencies of basal cells (P<0.0001), condensed chromatin cells (P<0.0001) and karyorrhectic cells (P<0.0001) were found to be significantly lower in Alzheimer’s patients, possibly reflecting changes in the cellular kinetics or structural profile of the buccal mucosa. Changes in telomere length were investigated using a quantitative RTm-PCR method to measure absolute telomere length (in Kb per diploid genome) and show agerelated changes in white blood cells and buccal cell telomere length (in kb per diploid genome) in normal healthy individuals and Alzheimer’s patients. We observed a significantly lower telomere length in white blood cells (P<0.0001) and buccal cells (P<0.01) in Alzheimer’s patients relative to healthy age-matched controls (31.4% and 32.3% respectively). However, there was a significantly greater telomere length in hippocampus cells of Alzheimer’s brains (P=0.01) compared to control samples (49.0). Buccal cells were also used to investigate chromosome 17 and 21 aneuploidy. A 1.5 fold increase in trisomy 21 (P<0.001) and a 1.2 fold increase in trisomy 17 (P<0.001) was observed in buccal cells of Alzheimer’s patients compared to age and gender matched controls. Chromosome 17 and chromosome 21 monosomy and trisomy increase significantly with age (P<0.001). Down’s syndrome, which exhibits similar neuropathological features to those observed in Alzheimer’s disease also showed a strong increase in chromosome 17 monosomy and trisomy compared to matched controls (P<0.001). However, aneuploidy rate for chromosome 17 and 21 in the nuclei of hippocampus cells of brains from Alzheimer’s patients and controls were not significantly different. Observations that AD individuals have altered plasma folate, B12 and Hcy levels compared to age-matched controls who have not been clinically diagnosed with AD were investigated. Genotyping studies were undertaken to determine whether polymorphisms within particular genes of the folate methionine pathway contributed to AD pathogenesis. Correlations between folate, B12 and Hcy status with previously determined buccal micronucleus assay cytome biomarkers for DNA damage, cell proliferation and cell death markers was investigated. Lastly, the potential protective effects of phytonutrient polyphenols on genomic instability events in a transgenic mouse model for AD were investigated. We determined the effects of curcumin and GSE polyphenols on DNA damage by testing the mice over a 9 month period utilizing a buccal micronucleus cytome assay, an erythrocyte micronucleus assay and measuring telomere length in both buccal cells and olfactory lobe brain tissue. / http://proxy.library.adelaide.edu.au/login?url= http://library.adelaide.edu.au/cgi-bin/Pwebrecon.cgi?BBID=1313395 / Thesis (Ph.D.) -- The University of Adelaide, School of Molecular and Biomedical Science, 2008

The aim of this thesis was to investigate the possibility of using buccal cells derived from a multi layered epithelial tissue from the oral mucosa as a model to identify potential biomarkers of genomic instability in relation to normal ageing and premature ageing syndromes such as AD and DS. A buccal micronucleus cytome assay was developed and used to investigate biomarkers for DNA damage, cell proliferation and cell death in healthy young, healthy old and young Down’s syndrome cohorts. Cells with micronuclei, karyorrhectic cells, condensed chromatin cells and basal cells increased significantly with normal ageing (P<0.0001). Cells with micronuclei and binucleated cells increased (P<0.0001) and condensed chromatin, karyorrhectic, karyolytic and pyknotic cells decreased (P<0.002) significantly in Down’s syndrome relative to young controls. The buccal micronucleus cytome assay was used to measure ratios of buccal cell populations and micronuclei in clinically diagnosed Alzheimer’s patients compared to age and gender matched controls. Frequencies of basal cells (P<0.0001), condensed chromatin cells (P<0.0001) and karyorrhectic cells (P<0.0001) were found to be significantly lower in Alzheimer’s patients, possibly reflecting changes in the cellular kinetics or structural profile of the buccal mucosa. Changes in telomere length were investigated using a quantitative RTm-PCR method to measure absolute telomere length (in Kb per diploid genome) and show agerelated changes in white blood cells and buccal cell telomere length (in kb per diploid genome) in normal healthy individuals and Alzheimer’s patients. We observed a significantly lower telomere length in white blood cells (P<0.0001) and buccal cells (P<0.01) in Alzheimer’s patients relative to healthy age-matched controls (31.4% and 32.3% respectively). However, there was a significantly greater telomere length in hippocampus cells of Alzheimer’s brains (P=0.01) compared to control samples (49.0). Buccal cells were also used to investigate chromosome 17 and 21 aneuploidy. A 1.5 fold increase in trisomy 21 (P<0.001) and a 1.2 fold increase in trisomy 17 (P<0.001) was observed in buccal cells of Alzheimer’s patients compared to age and gender matched controls. Chromosome 17 and chromosome 21 monosomy and trisomy increase significantly with age (P<0.001). Down’s syndrome, which exhibits similar neuropathological features to those observed in Alzheimer’s disease also showed a strong increase in chromosome 17 monosomy and trisomy compared to matched controls (P<0.001). However, aneuploidy rate for chromosome 17 and 21 in the nuclei of hippocampus cells of brains from Alzheimer’s patients and controls were not significantly different. Observations that AD individuals have altered plasma folate, B12 and Hcy levels compared to age-matched controls who have not been clinically diagnosed with AD were investigated. Genotyping studies were undertaken to determine whether polymorphisms within particular genes of the folate methionine pathway contributed to AD pathogenesis. Correlations between folate, B12 and Hcy status with previously determined buccal micronucleus assay cytome biomarkers for DNA damage, cell proliferation and cell death markers was investigated. Lastly, the potential protective effects of phytonutrient polyphenols on genomic instability events in a transgenic mouse model for AD were investigated. We determined the effects of curcumin and GSE polyphenols on DNA damage by testing the mice over a 9 month period utilizing a buccal micronucleus cytome assay, an erythrocyte micronucleus assay and measuring telomere length in both buccal cells and olfactory lobe brain tissue. / http://proxy.library.adelaide.edu.au/login?url= http://library.adelaide.edu.au/cgi-bin/Pwebrecon.cgi?BBID=1313395 / Thesis (Ph.D.) -- The University of Adelaide, School of Molecular and Biomedical Science, 2008

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