Decreased mitochondrial function is associated with aging and is an early step in Alzheimer's disease (AD). Autophagy also declines with age and is required for degradation of dysfunctional mitochondria but it is not known whether autophagosomal formation is overactive and/or degradation of autophagosomes is inhibited in AD. Although two-thirds of the 5 million Americans diagnosed with AD are women, without a clear mechanism. Since the role of gender and autophagy in AD is unclear, we wanted to know whether: A) decreased mitochondrial biogenesis precedes brain plaque formation, neuronal death and memory deficits B) autophagosomal formation is overactive and/or degradation of autophagosomes is inhibited in AD and C) deficits in mitochondrial biogenesis and autophagy occur earlier in life in the hippocampus/cortex of female AD-Tg, than male AD-Tg mice. To answer these questions, mitochondrial DNA (mtDNA), TFAM (transcription factor A mitochondrial) and two stages in autophagy, autophagosomal formation and degradation were measured in the hippocampus/cortex of non-transgenic (non-Tg) and the APP(Swe, DI)/NOS2-/- AD mouse model (AD-Tg) from 2 mo. through 12 mo. of age, when memory deficits develop. Male and female mice were evaluated for gender differences. By measuring mitochondrial gene copy number relative to nuclear gene copy number by qPCR, we found female specific decreases in mtDNA and TFAM protein levels in AD-Tg hippocampus/cortex, before 12 mo., when memory deficits develop. The male AD-Tg mice did not show any decline in the levels of mtDNA or TFAM protein through 12 mo. of age, indicating a decline in mitochondrial biogenesis earlier in life in female AD-Tg mice, than males. To determine whether autophagosomal formation is overactive and/or autophagosomal degradation is inhibited in AD, non-Tg and AD-Tg mouse neurons from 2-12 mo. of age were cultured and transfected with an adenovirus expressing the dual fusion protein, mCherry-GFP-LC3B. This system enables the distinction of early (autophagosomal formation) from late (autophagosomal degradation) stages of autophagy. Autophagosomal formation increased in female AD-Tg mice, while male AD-Tg neurons have decreased formation of autophagosomes, compared to non-Tg. Neurons from AD-Tg mice show deficits in degradation of autophagosomes by 2 mo. Our results show increased autophagosomal formation in female neurons with age and in our AD-like model without corresponding increases in degradation of autophagosomes. All together, our data indicates that the presence of familial APP mutations and knockout of NOS2 increases deficits in both mitochondrial biogenesis and autophagy in female mice, compared to males. These deficits occur before amyloid plaque formation and memory deficits, suggesting that mitochondrial and autophagic deficits may play a role in the higher incidence of AD in females.

Intentions have a special status in such important cognitive operations as prospective memory, or remembering to execute actions in the future. Indeed, recent research has shown that future-oriented information (such as intentions) have a higher and more sustained level of activation in mind than do other forms of to-be-remembered information. Such enhanced activation increases the accessibility of intentions for future retrieval operations, a phenomenon known as the “intention superiority effect.” Thus far, all research on the intention superiority effect has used facilitation paradigms, in which attending selectively to relevant stimuli facilitates performance on tasks that benefit from the processing of that information. The current investigation examines whether the intention superiority effect is also observed in an interference paradigm, in which sources of influence are in opposition. No previous research has demonstrated that the intention superiority effect is robust across such paradigm characteristics. Therefore, the first objective of the present study is to use a Stroop task to test the intention superiority effect within an interference paradigm. Previous research on the intention superiority effect has been conducted largely with undergraduate university students. Little is known about whether this effect exists for cognitively vulnerable populations, such as older adults. Arguably, the absence of an intention superiority effect could account for lower performance in such related cognitive tasks as prospective memory. Therefore, the second objective of this research was to examine whether the intention superiority effect, as produced by an interference paradigm, exists also for older adults. In a series of four experiments, participants received a brief Stroop word list including critical words from a previously encoded intention. We predicted that there would be more interference with colour naming for words that belonged to an intention that participants intended to carry out versus an intention that they did not have to carry out (i.e., intention superiority effect). Results of the four experiments for both young and older adults revealed longer latencies for words belonging to an intention that they intended to carry out. These data are the first demonstration of an intention superiority effect in an interference paradigm as well as the first demonstration of this effect in an older adult age group. / Graduate

Master of Science / Department of Food, Nutrition, Dietetics and Health / Mark Haub / The coronary microcirculation is the principle site of blood flow control and myocardium oxygen delivery within the coronary artery tree. Coronary arteriole tone is determined by three major endothelium derived vasoactive substances: endothelin, nitric oxide (NO), and reactive oxygen species (ROS). The effects of these substances change with aging and differ between sexes. Endothelin-1 (ET-1), the primary endothelin isoform in the coronary circulation, acts on smooth muscle receptors endothelin-A (ET[subscript A]) and endothelin-B (ET[subscript B]) to induce vascular smooth muscle (VSM) contraction and vasoconstriction. Whereas ET-1 activation of the ET[subscript B] receptor on the endothelium initiates a cascade of events leading to NO production via endothelium derived NO synthase (eNOS) enzyme activation and VSM relaxation. Aged males maintain ET[subscript A] receptor expression and higher levels of vasoconstriction than do age-matched females. High levels of ET[subscript A] receptor activity are associated with hypertension, myocardial infarction, coronary artery spasm, atherosclerosis, and finally heart failure (HF). Additionally, NO can displace ET-1 from the VSM ET[subscript A] and ET[subscript B] receptors. Thus, with reduced eNOS activity and decreased NO production, there is a simultaneous loss of vasodilatory capacity and increase in vasoconstrictive capacity. In both rodent and human models aged males and females ROS production increases with age. ROS, such as superoxide, scavenge NO, decreasing its bioavailability and producing peroxynitrite. Peroxynitrite is a potent reactive nitrogen species that leads to endothelial cell apoptosis and eNOS enzyme dissociation, potentiating superoxide production and NO reduction. It has been shown that the reduction in NO bioavailability may be a primary mechanism of coronary artery disease. However, the ROS hydrogen peroxide, also increased with aging, produces a potent vasodilatory effect in the coronary microcirculation and seems to be one mechanism that buffers the loss of NO-induced vasodilation. In postmenopausal women diminished estrogen levels further reduce eNOS production of NO. Males, however, tend to experience decrements in arteriole function a decade before women and estrogen may be one mechanism preserving vascular health into middle age that separates the chronology of coronary artery disease between sexes. Determining the mechanisms of disease onset that accompany the aging process will provide insight into potential therapies to preserve endothelium dependent dilation with aging such as exercise, dietary NO supplementation, and increased dietary anti-oxidant consumption.

Made available in DSpace on 2016-02-05T18:30:08Z (GMT). No. of bitstreams: 0 Previous issue date: 2015-07-30. Added 1 bitstream(s) on 2016-02-05T18:34:15Z : No. of bitstreams: 1 000857749.pdf: 1246716 bytes, checksum: 2fda392ee4e862d1d9a68521249ab3ef (MD5) / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / Alterações do eixo hipotálamo-hipófise-gônadas em fêmeas determinam a transição de ciclos reprodutivos regulares para irregulares, com perda da fertilidade. Interação dos neurônios GnRH e esteróides gonadais está interligado pelas alças de retroalimentação e alterações nesse mecanismo estão relacionados com a senescência reprodutiva. Estímulos da noradrenalina (NA) e neurônios da área pré-óptica (APO) são essenciais para liberação das gonadotrofinas, pois neurônios GnRH expressam receptores para estrógeno β e progesterona. O objetivo deste estudo foi avaliar a atividade das células neuronais da APO no período de transição para a estropausa em ratas Wistar. Ratas Wistar cíclicas (4-5 meses) no dia do estro e acíclicas (17-18 meses) em constante estro (CE) foram perfundidas ou decapitadas às 10, 14 e 18 horas. Encéfalos perfundidos foram processados por imunohistoquímica para avaliação da imunorreatividade para antígenos relacionados ao Fos da APO. Após a decapitação, o encéfalo foi retirado e realizado microdissecção da APO e determinação do conteúdo de NA e seu metabolito; o plasma foi utilizado para dosagens de LH, FSH, E2 e P4. Os resultados obtidos evidenciaram secreção plasmática maior de LH e menor de FSH e E2 no grupo de ratas acíclicas. O número de neurônios FRA-IR foi maior em ratas acíclicas, nos horários das 10 (p<0,001) e das 18 (p<0,05) em relação ao grupo de animais com ciclo regular. Nas ratas acíclicas, o conteúdo armazenado de NA foi menor às 14h e 18h (p<0,001) e o metabólito foi constante e maior às 18h, comparada com o mesmo horário das ratas do grupo cíclica (p<0,05). Conclui-se que alterações neurais e ovarianas que ocorrem no CE determinam o declínio para a ocorrência da ciclicidade dos ciclos e caracterizam o período de periestropausa / Changes of the hypothalamic-pituitary-gonadal axis in females determine the transition from regular to irregular reproductive cycles, with a loss of fertility. Interaction of GnRH neurons and gonadal steroid is connected by feedback and changes in this mechanism are related to reproductive senescence. Noradrenaline (NE) stimulation and preoptic area (POA) neurons are essential for release of gonadotropins, as GnRH neurons express receptors for estrogen β and progesterone. The objective of this study was to evaluate the activity of neurons in POA nuclei, in transition period for estropause in Wistar rats. Cyclic Wistar rats (4-5 months) on the day of estrus and acyclic (17-18 months) in estrus constant (CE) were decapitated or perfused at 10, 14 and 18 hours. Perfused brains were processed for immunohistochemistry to evaluate the immunoreactivity to antigens related to the Fos in POA. After decapitation, the brain was removed and carried microdissection of POA and determining the content of NE and its metabolite; Plasma was used for measurements of LH, FSH, E2 and P4. The results showed higher plasma secretion of LH, FSH and E2 lower in the group of acyclic rats. The number of FRA-IR neurons was higher in acyclic rats in the 10 hours (p <0.001) and 18 (p <0.05) compared to the group of animals with regular cycle. In rats acyclic, the stored contents of NE was lower at 14h and 18h (p <0.001), and the metabolite was constant and greater at 18h compared to the same time of the rats of the cyclic group (p <0.05). It follows that neural and ovarian changes that occur in the CE decline to determine the occurrence of cyclicity of cycles and featuring periestropausa period

Made available in DSpace on 2014-06-11T19:32:12Z (GMT). No. of bitstreams: 0 Previous issue date: 2011-02-08Bitstream added on 2014-06-13T20:23:13Z : No. of bitstreams: 1 seiva_fr_dr_botfm.pdf: 3896394 bytes, checksum: 25ac2f0fac725c9d2ad1833b75059c15 (MD5) / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / O envelhecimento populacional mundial é considerado um processo relativamente novo na história da humanidade e está associado a melhorias na área de prevenção e tratamento na saúde publica, bem como à diminuição da taxa de fertilidade, elevando rapidamente assim, o número de pessoas com mais de 60 anos em vários países ao redor do mundo (ACEVEDO, 1998). Embora esse aumento possa ser visto como um ponto positivo, ainda é preciso alcançar também melhorias na qualidade de vida entre as pessoas idosas. Comorbidades e complicações advindas de processos que acompanham o envelhecimento, tais quais, diabetes, sobrepeso e obesidade, hipertensão arterial, doenças neurodegenerativas e principalmente complicações cardiovasculares, ainda são problemas, que além de onerarem o sistema único de saúde, elevam a taxa de mortalidade na população senil. GH, ou hormônio de crescimento, produzido e secretado na hipófise anterior, atua direta ou indiretamente, via IGF-I (hormônio de crescimento insulina-símile) produzido principalmente no fígado, levando ao crescimento longitudinal ósseo, muscular e das cartilagens. O GH também é um importante mediador de algumas vias metabólicas, como a oxidação lipídica. Em relação ao metabolismo dos carboidratos, o GH apresenta efeitos antagônicos aos efeitos clássicos da insulina, sendo por muitos, considerado um hormônio diabetogênico (COPELAND et al, 1990; HAJIMA et al, 2005) / Life expectancy is increasing in world population and with it, the incidence of public health problems such as obesity and cardiac alterations. Because growth hormone (GH) concentration is referred to be decreased in aging conditions, a question must be addressed: what is the effect of GH on aging related adverse changes? To investigate the effects of GH on cardiac energy metabolism and its association with calorimetric parameters, lipid profile and oxidative stress in aged and obese rats, initially 32 male Wistar rats were divided into two groups (n=16):(C) given standard-chow and water;(H) given hypercaloric-chow and receiving 30% sucrose in its drinking water. After 45 days, both C and H groups were divided into two subgroups (n=8):(C+PL) standard-chow, water and receiving saline subcutaneously;(C+GH) standard-chow, water and receiving 2 mg/kg/day rhGH subcutaneously;(H+PL) hypercaloricchow, 30% sucrose, receiving saline subcutaneously;(H+GH) hypercaloric-chow, 30% sucrose, receiving rhGH subcutaneously. After 30 days, C+GH and H+PL rats had higher body mass index, Lee-index, body fat content, percent-adiposity, serum triacylglycerol, cardiac lipid-hydroperoxide and triacylglycerol than C+PL. Energy-expenditure (RMR)/body weight, oxygen consumption and fat-oxidation were higher in H+GH than in H+PL. LDLcholesterol was highest in H+GH rats, whereas cardiac pyruvate-dehydrogenase and phosphofrutokinase activities were higher in H+GH and H+PL rats than in C+PL. In conclusion, the present study brought new insights on aging and obesity, demonstrating for the first time that GH therapy was harmful in aged and obesity conditions, impairing calorimetric parameters, lipid profile and oxidative stress. GH was disadvantageous in old rats, having undesirable effects on cardiac energy metabolism

Orientadora: Rita Cássia Menegati Dornelles / Banca: Cristiane Mota Leite / Banca: Fernanda Barbosa Lima Christian / Resumo: Alterações do eixo hipotálamo-hipófise-gônadas em fêmeas determinam a transição de ciclos reprodutivos regulares para irregulares, com perda da fertilidade. Interação dos neurônios GnRH e esteróides gonadais está interligado pelas alças de retroalimentação e alterações nesse mecanismo estão relacionados com a senescência reprodutiva. Estímulos da noradrenalina (NA) e neurônios da área pré-óptica (APO) são essenciais para liberação das gonadotrofinas, pois neurônios GnRH expressam receptores para estrógeno β e progesterona. O objetivo deste estudo foi avaliar a atividade das células neuronais da APO no período de transição para a estropausa em ratas Wistar. Ratas Wistar cíclicas (4-5 meses) no dia do estro e acíclicas (17-18 meses) em constante estro (CE) foram perfundidas ou decapitadas às 10, 14 e 18 horas. Encéfalos perfundidos foram processados por imunohistoquímica para avaliação da imunorreatividade para antígenos relacionados ao Fos da APO. Após a decapitação, o encéfalo foi retirado e realizado microdissecção da APO e determinação do conteúdo de NA e seu metabolito; o plasma foi utilizado para dosagens de LH, FSH, E2 e P4. Os resultados obtidos evidenciaram secreção plasmática maior de LH e menor de FSH e E2 no grupo de ratas acíclicas. O número de neurônios FRA-IR foi maior em ratas acíclicas, nos horários das 10 (p<0,001) e das 18 (p<0,05) em relação ao grupo de animais com ciclo regular. Nas ratas acíclicas, o conteúdo armazenado de NA foi menor às 14h e 18h (p<0,001) e o metabólito foi constante e maior às 18h, comparada com o mesmo horário das ratas do grupo cíclica (p<0,05). Conclui-se que alterações neurais e ovarianas que ocorrem no CE determinam o declínio para a ocorrência da ciclicidade dos ciclos e caracterizam o período de periestropausa / Abstract: Changes of the hypothalamic-pituitary-gonadal axis in females determine the transition from regular to irregular reproductive cycles, with a loss of fertility. Interaction of GnRH neurons and gonadal steroid is connected by feedback and changes in this mechanism are related to reproductive senescence. Noradrenaline (NE) stimulation and preoptic area (POA) neurons are essential for release of gonadotropins, as GnRH neurons express receptors for estrogen β and progesterone. The objective of this study was to evaluate the activity of neurons in POA nuclei, in transition period for estropause in Wistar rats. Cyclic Wistar rats (4-5 months) on the day of estrus and acyclic (17-18 months) in estrus constant (CE) were decapitated or perfused at 10, 14 and 18 hours. Perfused brains were processed for immunohistochemistry to evaluate the immunoreactivity to antigens related to the Fos in POA. After decapitation, the brain was removed and carried microdissection of POA and determining the content of NE and its metabolite; Plasma was used for measurements of LH, FSH, E2 and P4. The results showed higher plasma secretion of LH, FSH and E2 lower in the group of acyclic rats. The number of FRA-IR neurons was higher in acyclic rats in the 10 hours (p <0.001) and 18 (p <0.05) compared to the group of animals with regular cycle. In rats acyclic, the stored contents of NE was lower at 14h and 18h (p <0.001), and the metabolite was constant and greater at 18h compared to the same time of the rats of the cyclic group (p <0.05). It follows that neural and ovarian changes that occur in the CE decline to determine the occurrence of cyclicity of cycles and featuring periestropausa period / Mestre

Orientador: Rosana de Fátima Possobon / Dissertação (mestrado profissional) - Universidade Estadual de Campinas, Faculdade de Odontologia de Piracicaba / Made available in DSpace on 2018-08-25T21:56:58Z (GMT). No. of bitstreams: 1 Pereira_LuizetedeSousaAlexandre_M.pdf: 3174824 bytes, checksum: ecd53e664a1c9e6a71a57c37f3ebfdab (MD5) Previous issue date: 2014 / Resumo: A expectativa de vida aumentou no mundo e no Brasil e a mudança na pirâmide etária, decorrente desse processo, implica a necessidade de se repensar as políticas sociais, especialmente as da área de saúde. Este estudo teve como objetivo avaliar a associação entre a qualidade de vida do idoso e do cuidador e sua relação com o grau de sobrecarga do cuidador e grau de dependência do idoso no município de Santa Cruz do Rio Pardo/SP. Trata-se de um estudo transversal analítico, realizado com 203 idosos e 164 cuidadores, cadastrados nas unidades de saúde do município de Santa Cruz do Rio Pardo, interior do estado de São Paulo. Foram utilizados os instrumentos de avaliação: Escala MIF para avaliação do grau de dependência do idoso; Escala Zarit para avaliação do grau de sobrecarga do cuidador; Questionário Socioeconômico e Questionário WHOQOL-bref para avaliação da qualidade de vida do idoso e do cuidador; avaliação das condições da saúde bucal dos idosos; questionário de dados relacionados aos medicamentos consumidos, com ou sem prescrição médica, para mensurar a prevalência da automedicação dos idosos. Entre os 203 idosos entrevistados, a maioria era do sexo feminino (68%), na faixa etária entre 60 a 100 anos, de baixa renda, não alfabetizados e arranjo domiciliar com até 3 pessoas na família. Constatou- se a presença de 453 agravos de saúde, ou seja, tipos diferentes de doenças, sendo que 72,4% dos idosos apresentavam mais do que uma patologia. A maior prevalência estava relacionada ao aparelho circulatório (37,5%), sendo que os agravos que mais acometem esse grupo eram a hipertensão arterial essencial (19,2%), seguida de acidente vascular cerebral. Os idosos faziam uso, em média, de 5,5 medicamentos por dia, havendo uma minoria que se automedicava. A média do índice CPO-D foi de 29,3, sendo que 68,4% eram entulhos, 32% usavam prótese total e apenas 5,91% apresentaram alterações em tecido mole, porém sem suspeita de malignidade. Em relação ao grau de dependência, mensurado pela Escala MIF, os resultados mostraram que mais da metade da amostra (53,7%) apresentava dependência moderada ou severa, ou seja, necessitavam de assistência de outra pessoa ou recurso de adaptação para desenvolver suas tarefas básicas diárias. No geral, os idosos apresentaram boa qualidade de vida. Houve associação significativa (p=0,000) entre o grau de dependência do idoso e a sua qualidade de vida. Com relação aos 164 cuidadores entrevistados, observou-se a predominância de mulheres (81,1 %), com idade entre 18 e 89 anos, sendo a maioria de baixa renda, baixa escolaridade e vivendo em arranjos domiciliares com até 3 pessoas na família. A maioria (81,4%) dos cuidadores era informal, sem curso especifico para cuidar de idosos, 85,7% dos cuidadores apresentavam grau de parentesco com os idosos e à responsabilidade de cuidar concentraram-se nos familiares mais próximos, tais como filhos e cônjuges. Mais da metade dos cuidadores (57,4%) relatou ter problemas de saúde, constatando-se 134 agravos. Em relação à sobrecarga de trabalho, mensurada pela Escala Zarit, a maioria dos cuidadores apresentava-se com baixo nível, sendo que não houve associação significativa entre o grau de sobrecarga do cuidador e o grau de dependência do idoso. No geral, os cuidadores apresentaram boa qualidade de vida, havendo associação significativa (p=0,000) entre qualidade de vida e sobrecarga do cuidador. Porém, não houve associação significativa entre o grau de dependência do idoso e a qualidade de vida do cuidador e também entre o grau de dependência do idoso e a sobrecarga do cuidador. Pode-se concluir que a sobrecarga do cuidador influencia sua qualidade de vida. Entretanto, o grau de dependência do idoso não exerce influencia sobre a qualidade de vida do cuidador, o que pode indicar que a sobrecarga do cuidador pode estar relacionada com a responsabilidade do ato de cuidar de uma pessoa de idade, sem importar o seu grau de dependência. Palavras-chaves: Envelhecimento; Idoso e Sobrecarga do Cuidador / Abstract: Life expectancy has increased worldwide and in Brazil and the change in the age structure, resulting from this process implies the need to rethink social policies, especially health care. This study aimed to evaluate the association between quality of life of the elderly and the caregiver and their relation to the degree of caregiver burden and degree of dependency of the elderly in the municipality of Santa Cruz do Rio Pardo / SP. This is an analytical cross-sectional study with 203 elderly and 164 caregivers, registered in health facilities in the municipality of Santa Cruz do Rio Pardo, in the state of São Paulo. Assessment instruments were used: MIF Scale for assessment of the degree of dependency of the elderly; Zarit scale for assessing the degree of caregiver burden; Socioeconomic questionnaire and the WHOQOL-Bref questionnaire for assessing quality of life of the elderly and the caregiver; assessment of the conditions of the oral health of the elderly; questionnaire related to the medications used, with or without medical prescription, to measure the prevalence of self-medication of older data. Among the 203 subjects interviewed, the majority were female (68%), aged between 60 to 100 years, low-income, illiterate and living arrangement with up to 3 people in the family. It was found the presence of health problems 453, or different kinds of diseases, and 72.4% of subjects had more than one pathology. The highest prevalence was related to the circulatory system (37.5%), and the hardships that most affect this group were essential hypertension (19.2%), followed by stroke. The elderly were using, on average, 5.5 medications per day, there is a minority who self-medicated. The average CPO-D index was 29.3, and 68.4% were rubble, 32% wore dentures and only 5.91% had alterations in soft tissue, but without suspicion of malignancy. Regarding the degree of dependence, measured by the MIF scale, the results showed that more than half of the sample (53.7%) had moderate or severe dependence, ie, needed assistance from another person or resource adaptation for development tasks basic daily. Overall, the elderly showed good quality of life. There was a significant association (p = 0.000) between the degree of dependency of the elderly and their quality of life. Regarding the 164 caregivers interviewed, there was a predominance of women (81.1%), aged between 18 and 89 years, mostly low-income, low education and living in household arrangements with up to 3 people in the family. The majority (81.4%) of caregivers were informal, without a specific course to take care of elderly, 85.7% of caregivers had kinship with the elderly and the responsibility of caring focused on close relatives, such as children and spouses. More than half of caregivers (57.4%) reported having health problems, noting were 134 injuries. Regarding workload, measured by the Zarit Scale, most caregivers presented with low level, and there was no significant association between the degree of caregiver burden and the degree of dependence of the elderly. Overall, caregivers showed good quality of life, no significant association (p = 0.000) between quality of life and caregiver burden. However, there was no significant association between the degree of dependency of the elderly and the quality of life of the caregiver and also between the degree of dependency of the elderly and caregiver burden. It can be concluded that caregiver burden affects their quality of life. However, the degree of dependency of the elderly does not exert influence on the quality of life of the caregiver, which may indicate that caregiver burden may be related to the responsibility of the act of caring for an elderly person, regardless of their degree of dependence. Keywords: Aging; Elderly and Caregiver burden / Mestrado / Odontologia em Saude Coletiva / Mestra em Odontologia em Saúde Coletiva

D.Sc. (Botany) / Senescence of Petunia hybrida petals is characterized by a typical climacteric respiration pattern. Pollination enhanced the rate of senescence and the start of the climacteric rise in respiration of the, corolla. Treatment with ethylene for a period of 6 hours had no effect on the rate of senescence, but increased the respiration rate. A ten hour treatment with ethylene increased the rates of both senescence and respiration. Initiation of the climacteric rise in respiration was also advanced. The cytochrome electron transport path was active throughout normal senescence and was the most important contributor to the total oxygen consumption by the petals during the pre- climacteric phase, while the contribution of the alternative pathway was minor. The contribution of the alternative pathway to oxygen consumption during the climacteric rise in respiration increased considerably, while the contribution of the cytochrome pathway decreased correspondingly. This suggests that the climacteric rise in respiration is due to an increase in the activity of the alternative pathway. Treatment with ethylene increased the contribution of the cytochrome pathway during the climacteric phase. Ethylene did not cause any significant increase in the activities of the processes of respiration preceding electron transport nor did it affect the availability of respiratory substrates. The results of this study suggest that the influence of ethylene on the electron transport system may be due to the effects of this hormone on the physical properties of the mitochondrial membranes.

M.Sc. / The senescence of climacteric flowers such as carnations is accompanied by an increase in ethylene synthesis during the later stages. This increase in ethylene synthesis is preceded by an increase in the sensitivity of the flowers to ethylene. The increase in ethylene sensitivity is accompanied by a concomitant increase in the levels of short-chain saturated fatty acids (SCSFAs). Treatment of carnation flowers with SCSFA results in an increase in ethylene sensitivity. It appears that these acids act by increasing membrane fluidity, causing slight conformational changes in membrane associated proteins and thereby increasing the ability of the tissue to bind ethylene to its membrane associated receptor molecules. The levels of SCSFAs in senescing carnation petals is controlled by the activity of the enzyme acetyl-coenzyme A carboxylase (ACCase). A decrease in the activity of this enzyme results in an increase in the levels of the SCSFAs and vice versa. During the senescence of carnation flowers, ACCase activity fluctuated from day to day. This fluctuation can be correlated to the fluctuations in the ethylene sensitivity of the flowers on a daily basis. In carnation petals, ACCase is located mainly in the plastids. ACCase activity could be controlled via feedback inhibition by long-chain fatty acids such as oleic acid. Treatment of carnation flowers with oleic acid resulted in a concomitant inhibition of ACCase activity, an increase in SCSFA-levels and an increase in ethylene sensitivity. Oleic acid is a competitive inhibitor of ACCase activity, and changes in the levels of oleic acid will affect the activity of the enzyme. An increase in oleic acid concentration resulted in a decrease in enzyme activity. However, in carnations it appears that ACCase activity is not controlled via feedback inhibition by long chain saturated fatty acids. The results of this study clearly show that ACCase activity is controlled directly by the expression of at least the biotinylated (BCCP) subunit of the enzyme. A decrease in the expression of the gene during the early stages of senescence coincided with a decrease in ACCase activity and was accompanied by a concomitant increase in ethylene sensitivity. These results indicate that the increase in ethylene sensitivity caused by an increase in SCSFA levels is directly controlled by the expression of the ACCase genes.

M.Tech. / The development of wrinkles is an aspect of ageing that causes people to become dissatisfied with their appearance. The most obvious or noticeable wrinkles on a person's face are those around and between the eyes. Treatment of, for example the wrinkles between the eyes, such as the most prominent frown lines, leads to a visible improvement of appearance ...