衰老是一個複雜的發病過程，它由多種因素引發，主要包括基因和遺傳。已經有很多研究報告表明能量限制（ER）可以延長果蠅的壽命，而芝麻素和黑米具有抗氧化活性。但是，基本的機制仍然不明。因此本研究檢驗ER，芝麻素和黑米萃取物（BRE）的抗衰老活性，並探討他們如何與CuZnSOD (SOD1)，MnSOD (SOD2)，catalase (CAT)，Methuselah（Mth）和Rpn11五個基因相互作用，參與果蠅的抗氧化防禦和衰老。 / 第一部分研究能量限制的抗衰老機制。果蠅隨機分成三組並餵養低能量 (0.393 kcal/ml), 標準能量 (SE; 0.784 kcal/ml) 和高能量(HE; 2.351 kcal/ml) 的食物。 能量減半的食物可以延長果蠅的平均壽命16%，這種作用伴隨著SOD1, SOD2 和Rpn11基因表達的上升。味覺試驗表明，能量限制的延長壽命作用與它顯著減少食物攝入量有關。急性paraquat實驗表明，能量限制可以延長野生型果蠅的壽命，而對超氧化物歧化酶突變果蠅的死亡無影響。同時，低能量的食可以緩解，而高能量的食則加速與年齡相關的攀爬能力的喪失。結果表明，能量限制可以延緩果蠅衰老，這種作用至少部分是由上調抗氧化基因的表達調控的。 / 第二部分研究芝麻素對果蠅壽命的影響。結果顯示，添加2和 5 mg/ml的芝麻素分別增加果蠅的平均存活時間13%和5%。進一步的研究表明，2 mg/ml芝麻素的抗衰老作用是通過上調SOD1，SOD2，CAT和Rpn11的基因表達實現的。另外，芝麻素可以延緩野生型果蠅的由paraquat引發的神經退行性疾病的進展，並且上調SOD1，SOD2和Rpn11的基因表達。急性paraquat實驗結果表明，芝麻素可以延長野生型和Aβ42 33769突變果蠅的壽命。由此得出結論，芝麻素可以延長果蠅壽命，並且減輕野生型果蠅的由paraquat引發的神經退行性疾病的症狀，這些作用至少部分是由基因SOD1，SOD2，CAT和Rpn11，而不是Mth調控的。 / 第三部分探討黑米萃取物的抗衰老作用。添加30mg/ml 的黑米萃取物可以延長果蠅的平均壽命14%，這是通過上調SOD1，SOD2，CAT和Rpn11，下調Mth基因的表達實現的。同時，黑米萃取物可以延緩野生型果蠅的由paraquat引發的神經退行性疾病的進展，伴隨著上調SOD1，SOD2和Rpn11的基因表達。 此外，補充黑米萃取物可以增加野生型和Aβ42 33769突變果蠅的生存時間。結果表明，黑米萃取物可以延長果蠅壽命，並且延緩野生型果蠅的由paraquat引發的神經退行性疾病的進程，這些作用至少部分是由基因SOD1，SOD2，CAT，Mth和Rpn11調控的。 / 總之，本研究揭示能量限制，補充抗氧化劑芝麻素和黑米萃取物可以改變黑腹果蠅的壽命。這些作用部分是由基因SOD1, SOD2, CAT, Rpn11 和Mth調控的。 / Aging is a complicated pathogenesis that is triggered by multiple factors mainly including genetics and environment. There have been numerous reports that demonstrate Energy Restriction (ER) could extend the lifespan of fruit fly, and sesamin and black rice possess antioxidant activity. However, the underlying mechanism remains unknown. The present study was therefore to examine the anti-aging activity of ER, sesamin and black rice extracts (BRE) and to investigate how they interacted with genes of CuZnSOD (SOD1), MnSOD (SOD2), catalase (CAT), Methuselah (Mth) and Rpn11 involved in the antioxidant defense and aging of Drosophila melanogaster. / Part I was to investigate the mechanism by which ER prolonged the lifespan of fruit fly. Fruit flies were divided into three groups and given one of three diets namely ER diet (0.393 kcal/ml), standard energy diet (SE; 0.784 kcal/ml) and high energy diet (HE; 2.351 kcal/ml). It was found that ER extended the mean lifespan by 16%, with elevated expressions of SOD1, SOD2 and Rpn11. Gustatory assay showed that the lifespan extension of ER was not related to the significantly less food intake. In addition, ER prolonged the lifespan of OR wild type fly, but not that of SOD mutant in the intensive paraquat test. Meanwhile, the ER diet could improve, while HE diet accelerated the age-dependent loss of climbing activity in OR wild type fly. Results confirmed that ER could delay the aging of fruit fly, mediated at least in part by up-regulating the genes of antioxidant enzymes. / Part II was to study the effect of sesamin supplementation on the lifespan of fruit fly. Results showed that sesamin at doses of 2 and 5 mg/ml diet increased the mean survival time by 13% and 5%, respectively. Further experiments demonstrated that the lifespan-prolonging activity of 2 mg sesamin/ml diet was accompanied by up-regulation of SOD1, SOD2, CAT and Rpn11. It was further observed that sesamin attenuated the paraquat-induced neurodegeneration in OR wild type fly, with up-regulation of SOD1, SOD2 and Rpn11. Sesamin also increased the survival time of OR wild type fly and Alzheimer mutant fly Aβ42 33769 with intensive paraquat treatment. It was therefore summarized that sesamin extended the lifespan and alleviated the neurodegeration in fruit fly, at least in part resulting from the interactions with genes SOD1, SOD2, CAT and Rpn11, not Mth. / Part III was to investigate the life-prolonging activity of BRE. Addition of 30 mg BRE into 1 ml diet (BRE30) could prolong the mean lifespan of fruit flies by 14%, accompanied with up-regulation of mRNA SOD1, SOD2, CAT and Rpn11, and down-regulation of Mth. It was also found that BRE30 could attenuate the paraquat-induced neurodegeneration in OR wild type fly, with up-regulation of SOD1, SOD2, CAT and Rpn11. In addition, BRE30 diet increased the survival time of OR wild type fly and Alzheimer mutant fly Aβ42 33769 exposed to paraquat. It was concluded that BRE could extend the lifespan and alleviate the neurodegeration in fruit fly, most likely by regulating the genes of SOD1, SOD2, CAT, Mth and Rpn11. / In summary, the present study found that the lifespan of fruit fly could be altered by ER and addition of antioxidants sesamin and BRE. The effect was in part regulated by genes SOD1, SOD2, CAT, Rpn11 and Mth. / Detailed summary in vernacular field only. / Detailed summary in vernacular field only. / Detailed summary in vernacular field only. / Detailed summary in vernacular field only. / Detailed summary in vernacular field only. / Zuo, Yuanyuan. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2012. / Includes bibliographical references (leaves 122-135). / Abstracts also in Chinese. / Acknowledgments --- p.I / Abstract --- p.II / List of abbreviations --- p.VII / Table of Contents --- p.IX / Chapter Chapter 1 --- General Introduction --- p.1 / Chapter 1.1 --- Introduction --- p.1 / Chapter 1.2 --- Human aging models --- p.2 / Chapter 1.2.1 --- Yeasts --- p.3 / Chapter 1.2.2 --- Nematodes --- p.3 / Chapter 1.2.3 --- Drosophila melanogaster --- p.4 / Chapter 1.2.4 --- Rodents --- p.5 / Chapter 1.2.5 --- Primates --- p.6 / Chapter 1.3 --- The aging process and behavioral senesce in D. melanogaster --- p.7 / Chapter 1.4 --- Anti-aging pathways in D. melanogaster --- p.8 / Chapter 1.4.1 --- Inhibition of respiration --- p.8 / Chapter 1.4.2 --- Metabolic rate --- p.9 / Chapter 1.4.3 --- Oxidative stress --- p.10 / Chapter 1.4.4 --- Apoptotic pathways --- p.10 / Chapter 1.4.5 --- The Insulin/IGF-1 like signaling (IIS) pathway --- p.11 / Chapter 1.4.7 --- The sirtuin pathway --- p.12 / Chapter 1.4.8 --- The olfactory system --- p.12 / Chapter 1.5 --- Free radical theory of aging --- p.13 / Chapter 1.5.1 --- Free radicals --- p.14 / Chapter 1.5.2 --- Antioxidant system --- p.19 / Chapter 1.5.2.1 --- Antioxidant enzymes --- p.19 / Chapter 1.5.2.2 --- Non-enzymatic antioxidants --- p.21 / Chapter 1.6 --- Energy restriction --- p.24 / Chapter 1.6.1 --- ER or fasting in humans --- p.24 / Chapter 1.6.2 --- ER in D. melanogaster --- p.25 / Chapter 1.6.3 --- Response of oxidative stress to ER in D. melanogaster --- p.25 / Chapter 1.7 --- Exogenous antioxidants --- p.27 / Chapter 1.7.1 --- Sesamin --- p.30 / Chapter 1.7.2 --- Black rice extracts --- p.30 / Chapter 1.8 --- Age-related biomarkers in D. melanogaster --- p.31 / Chapter 1.8.1 --- Behavioral changes in D. melanogaster --- p.31 / Chapter 1.8.2 --- Paraquat-induced mortality in D. melanogaster --- p.32 / Chapter 1.8.3 --- Age-related genes --- p.32 / Chapter Chapter 2 --- Lifespan extension, oxidative stress and energy restriction in fruit flies --- p.36 / Chapter 2.1 --- Introduction --- p.36 / Chapter 2.2 --- Objectives --- p.39 / Chapter 2.3 --- Materials and methods --- p.39 / Chapter 2.3.1 --- Fly stocks --- p.39 / Chapter 2.3.2 --- Diet --- p.39 / Chapter 2.3.3 --- Lifespan assay --- p.42 / Chapter 2.3.4 --- Measurement of body weight --- p.42 / Chapter 2.3.5 --- Gustatory assay --- p.42 / Chapter 2.3.6 --- Climbing assay --- p.43 / Chapter 2.3.7 --- Paraquat treatment --- p.43 / Chapter 2.3.8 --- SOD activity --- p.44 / Chapter 2.3.9. --- CAT activity --- p.45 / Chapter 2.3.10 --- Real-Time PCR --- p.46 / Chapter 2.3.11 --- Western blot analysis --- p.48 / Chapter 2.3.12 --- Statistics --- p.49 / Chapter 2.4 --- Results --- p.49 / Chapter 2.4.1 --- Lifespan extension of ER in fruit flies --- p.49 / Chapter 2.4.2 --- Changes of food intake and locomotor function in fruit flies --- p.50 / Chapter 2.4.3 --- Resistance to paraquat-induced oxidative stress in fruit flies --- p.50 / Chapter 2.4.4 --- Influence of ER on enzymatic activity, gene expression and protein expression in fruit flies --- p.51 / Chapter 2.5 --- Discussion --- p.60 / Chapter Chapter 3 --- Sesamin extends lifespan of fruit flies --- p.63 / Chapter 3.1 --- Introduction --- p.63 / Chapter 3.2 --- Objectives --- p.69 / Chapter 3.3 --- Materials and methods --- p.69 / Chapter 3.3.1 --- Chemicals --- p.69 / Chapter 3.3.2 --- Fly stocks --- p.69 / Chapter 3.3.3 --- Diet --- p.70 / Chapter 3.3.4 --- Lifespan assay --- p.70 / Chapter 3.3.5 --- Measurement of body weight --- p.71 / Chapter 3.3.6 --- Gustatory assay --- p.71 / Chapter 3.3.7 --- Intensive paraquat treatment --- p.72 / Chapter 3.3.8 --- Chronic paraquat treatment --- p.72 / Chapter 3.3.9 --- Climbing assay --- p.73 / Chapter 3.3.10 --- Diets switch experiment --- p.73 / Chapter 3.3.11 --- SOD activity --- p.74 / Chapter 3.3.12 --- CAT activity --- p.74 / Chapter 3.3.13 --- Real-time PCR --- p.74 / Chapter 3.3.14 --- Western blot analysis --- p.74 / Chapter 3.3.15 --- Statistics --- p.75 / Chapter 3.4 --- Results --- p.75 / Chapter 3.4.1 --- Lifespan extension of sesamin in fruit flies --- p.75 / Chapter 3.4.2 --- Results of diets switch --- p.76 / Chapter 3.4.3 --- Effect of sesamin on intensive paraquat treatment in OR, SOD{U+207F}¹°⁸, Aβ42 32038 and Aβ42 33769 flies --- p.77 / Chapter 3.4.4 --- Effect of sesamin on chronic paraquat treatment in OR flies --- p.78 / Chapter 3.5 --- Discussions --- p.92 / Chapter Chapter 4 --- Black rice extract extends lifespan of fruit flies --- p.96 / Chapter 4.1 --- Introduction --- p.96 / Chapter 4.2 --- Objectives --- p.97 / Chapter 4.3 --- Materials and methods --- p.97 / Chapter 4.3.1 --- Chemicals --- p.97 / Chapter 4.3.2 --- Fly stocks --- p.97 / Chapter 4.3.3 --- Diet --- p.98 / Chapter 4.3.4 --- Lifespan assay --- p.98 / Chapter 4.3.5 --- Measurement of body weight --- p.99 / Chapter 4.3.6 --- Gustatory assay --- p.99 / Chapter 4.3.7 --- Intensive paraquat treatment --- p.99 / Chapter 4.3.8 --- Chronic paraquat treatment --- p.99 / Chapter 4.3.9 --- Climbing assay --- p.100 / Chapter 4.3.10 --- Diets switch experiment --- p.100 / Chapter 4.3.11 --- SOD activity --- p.100 / Chapter 4.3.12 --- Real-time PCR --- p.100 / Chapter 4.3.13 --- Western blot analysis --- p.101 / Chapter 4.3.14 --- Statistics --- p.101 / Chapter 4.4 --- Results --- p.101 / Chapter 4.4.1 --- Lifespan extension of BRE in fruit flies --- p.101 / Chapter 4.4.2 --- Results of diets switch --- p.102 / Chapter 4.4.3 --- Effect of BRE on intensive paraquat treatment in OR, SOD{U+207F}¹°⁸, Aβ42 32038 and Aβ42 33769 flies --- p.103 / Chapter 4.4.4 --- Effect of BRE on chronic paraquat treatment in OR flies --- p.104 / Chapter 4.5 --- Discussion --- p.118 / References --- p.122

Changes in synaptic strength underlie synaptic plasticity, the cellular substrate for learning and memory. Disruptions in the mechanisms that regulate synaptic strength closely link to many developmental, neurodegenerative and neurological disorders. Release site probability (PAZ) and active zone number (N) are two important presynaptic determinants of synaptic strength; yet, little is known about the processes that establish the balance between N and PAZ at any synapse. Furthermore, it is not known how PAZ and N are rebalanced during synaptic homeostasis to accomplish circuit stability. To address this knowledge gap, we adapted a neurophysiological experimental system consisting of two functionally differentiated glutamatergic motor neurons (MNs) innervating the same target. Average PAZ varied between nerve terminals, motivating us to explore benefits for high and low PAZ, respectively. We speculated that high PAZ confers high-energy efficiency. To test the hypothesis, electrophysiological and ultrastructural measurements were made. The terminal with the highest PAZ released more neurotransmitter but it did so with the least total energetic cost. An analytical model was built to further explore functional and structural aspects in optimizing energy efficiency. The model supported that energy efficiency optimization requires high PAZ. However, terminals with low PAZ were better able to sustain neurotransmitter release. We suggest that tension between energy efficiency and stamina sets PAZ and thus determines synaptic strength. To test the hypothesis that nerve terminals regulate PAZ rather than N to maintain synaptic strength, we induced sustained synaptic homeostasis at the nerve terminals. Ca2+ imaging revealed that terminals of the MN innervating only one muscle fiber utilized greater Ca2+ influx to achieve compensatory neurotransmitter release. In contrast, morphological measurements revealed that terminals of the MN inner vating multiple postsynaptic targets utilized an increase in N to achieve compensatory neurotransmitter release, but this only occurred at the terminal of the affected postsynaptic target. In conclusion, this dissertation provides several novel insights into a prominent question in neuroscience: how is synaptic strength established and maintained. The work indicates that tension exists between energy efficiency and stamina in neurotransmitter release likely influences PAZ. Furthermore, PAZ and N are rebalanced differently between terminals during synaptic homeostasis. / Includes bibliography. / Dissertation (Ph.D.)--Florida Atlantic University, 2015. / FAU Electronic Theses and Dissertations Collection