"Artemisinin is a potent antimalarial drug produced in the plant Artemisia annua. Earlier reports suggested that the roots play a key role in artemisinin production; however, it was not clear if other factors actually affected production instead of roots. Here the role of roots and two phytohormones, NAA and BAP, were studied to determine what role each plays in artemisinin production in the plant. Rooted Artemisia annua shoots produced significantly more artemisinin, arteannuin B, and deoxyartemisinin, the end products in the pathway, than unrooted shoots. Although roots do not seem to affect the levels of precursors, artemisinic acid and dihydroartemisinic acid, or regulate the transcription of the genes in the pathway, rooted plants developed larger trichome sacs suggesting that the accumulation of end products is linked to the expansion of the trichome sac. Unrooted shoots are grown in shooting medium containing higher amount of MS salts, vitamins, sucrose and two potent phytohormones, NAA and BAP. Rooted shoots grown in rooting medium containing either one or both of these hormones showed that NAA increased production of arteannuin B in the young leaves and artemisinin in the mature leaves; in mature leaves, however, arteannuin B was inhibited by NAA. BAP induced production of both the precursors and the end products, except for artemisinin, in the young and/or mature leaves. When rooted shoots with their roots removed were grown in rooting medium containing either one of these hormones, artemisinin was significantly less in cultures grown with BAP while there were no differences in metabolite levels in cultures grown with NAA. Although the importance of roots on the artemisinin biosynthetic pathway cannot be concluded, these results help improve our understanding of artemisinin biosynthesis as may prove useful for improving artemisinin production in field-grown crops."

The first part of this thesis discusses developmental influences on the human connectome in relation to autism and attention deficit hyperactivity disorder (ADHD), conditions associated with alterations in brain connectivity and marked by social impairments. It reports an experiment investigating whether the connectomes of individuals with autism or ADHD differ from the connectome of neurotypical individuals, and what the underlying genetic basis could be for any differences in neural architecture. Chapter 2 reports an analysis of networks in children with autism or ADHD, using structural covariance magnetic resonance imaging (scMRI). We found overlapping as well as distinct network features across both conditions. Chapter 3 reports an analysis of how gene expression might be associated with the basic building blocs of these structural covariance networks. We found that synaptic and transcriptionally downregulated genes were replicably associated with cortical thickness differences in children with autism, but not in children with ADHD. In addition, the first part also aims to elucidate the potential modulation effects of sex on autism neurobiology. Chapter 4 reports an analysis of structural covariance networks in male and female adults with and without autism. We found that biological sex is a modulator of neurobiological heterogeneity in autism. Chapter 5 reports pilot data aiming to identify an electrophysiological signature of these network properties using electroencephalography (EEG). We find little evidence for theories about network asymmetry, but indications of altered frontal network integration. The second part of the thesis examines the acute effects of hormones on brain connectomics. Hormones are an integral part of the mechanism of social behaviour. In a series of hormone administration studies, we report experiments to test the acute effects of steroid and peptide hormones on brain functional connectivity (Chapters 6 and 7). Chapter 6 reports an oxytocin administration study that used a novel data-driven approach to assess resting-state fMRI connectivity in women. Although the number of fMRI studies on oxytocin have increased over past years, little is known about its effect on women. We found that oxytocin robustly enhances cortico-subcortical connectivity, and that this effect positively correlates with autistic traits. This is interesting given that oxytocin has been proposed as a potential therapeutic in autism. Chapter 7 reports an experiment testing if testosterone modulates connectivity in a specific social environment (a fear response). This was confirmed during the social task, but not during baseline resting-state, highlighting the role of testosterone in functional connectivity in this specific context. Chapter 8 is the concluding chapter that integrates all the empirical findings in the thesis. We discuss their implications for our understanding of autism and ADHD, and of the role of steroid and peptide hormones in the typically and atypically developing connectome. Chapter 8 also reflects on the limitations of the experiments reported, and sets out future directions for research in this area.

Secretory granule biogenesis describes the events leading up to the budding of a nascent granule from the trans Golgi network. Literature surrounding secretory granule biogenesis is conflicting and has generated much debate. This thesis aims to address the important issues of this debate by utilizing the insulin-producing liver cell line HUH7-ins. This cell line has been shown to synthesize, store and secrete mature insulin in response to glucose via the possession of secretory granules. Using microarray technology the gene expression profile of HUH7-ins cells was compared with parental HUH7 cells, hoping to identify possible candidate genes contributing to secretory granule biogenesis. 164 genes were shown to be differentially expressed although no known granulogenic protein exhibited a change in expression. The data did suggest a nervous system differentiation event and implicates myosin Vc in the regulated secretion of insulin. HUH7-ins cells express a number of granulogenic protein mRNAs and while chromogranin B (CgB) protein level remained constant upon insulin expression, a significant increase in the level of chromogranin A (CgA) was observed, though the significance of this increase in expression is unknown. The over-expression of CgA in a clone of HUH7-ins that did not possess the regulated secretory pathway was unable to rescue the regulated secretory pathway, suggesting that CgA expression alone is unable to form secretory granules in our model. To determine if the secretory granule biogenesis seen in HUH7-ins cells was specific to insulin, three prohormones of different neuroendocrine origin were over-expressed in HUH7 cells; amylin ( cell), pancreatic polypeptide (pancreatic islet) and proopiomelanocortin (pituitary). None of these prohormones were able to form structures in the cytoplasm that resembled secretory granules by immunofluorescent microscopy, nor did they induce the expression of CgA. No prohormone was detected in cell lysates or conditioned media, raising the possibility that these exogenous prohormone aggregates are trafficked to the lysosomal/endosomal system for degradation. This study provides significant information regarding the genome-wide expression changes induced upon secretory granule biogenesis in a liver cell line, describes the lack of effect of CgA in this event and suggests that secretory granule biogenesis in this liver cell line is specific to insulin.

Thèse (M.Sc.)--Université Laval, 200. / Bibliogr.: f. 68-75. Publié aussi en version électronique.

Previous work in this laboratory revealed that hormone analysis using fecal samples may predict the number of fetuses carried by pregnant ewes at mid- to late gestation. Reliable lambing number prediction is useful to the producer. Using gas chromatography/mass spectrometry the 5��- and 5��-series of pregnanes and selected 4- and 5-pregnenes were monitored in the feces of 36 black and white-face cross ewes during early gestation. Feces were collected at d 5, 19, and 30 post-mating. Endoscopy was used at d 6 to determine the number of corpora lutea, and litter size data were collected at term. The number of copora lutea was not related (P>.05) to hormone concentrations at any of the sampling times (ANOVA-GLM). No differences in hormone levels were detected at d 5 in response to lambing number. At d 19, 5��-pregnane-3,20-dione and 5��-pregnane-3��,20��-diol were higher in ewes carrying triplets than ewes carrying twins (P���.008). At d 30, 3��-hydroxy-5��-pregnan-20-one was higher in ewes carrying triplets than twins (P<.05). Five progestins, including progesterone and 20��-hydroxy-4-pregnen-3- one, were lower at d 5 in ewes that conceived (n=26) than in ewes that did not conceive (n=6) at the first mating (P<.05). Concentrations of ten progestins were different (P<.05) (some higher and some lower) between groups of ewes that conceived at the first mating versus those that conceived at the second mating. In ewes that conceived at the second mating, pregnenolone and 5��-pregnane-3,20- dione were higher (P<.05) at d 5 than at d 5 of their previous non-conceptive cycle. Of the six ewes that were mated a second time, two still did not conceive but had elevated concentrations of three 5��-pregnanes (P<.05). Although there are differences in progestin profiles in ewes carrying different numbers of fetuses, concentrations alone are not adequate predictors of prolificacy at early gestation. It is inconclusive whether detection of pregnancy is possible as early as d 5 of gestation. / Graduation date: 2001

Thesis (M. Phil.)--University of Hong Kong, 2006. / Title proper from title frame. Also available in printed format.

Seed vigor, although not well understood, is a key critical component for yield and is in part due to a well establishment and vigorous stand of canola (<i>Brassica napus</i>) seedling under less than ideal conditions in Western Canada. My objective was to determine what constitutes vigor by studying the response of a black seed line and a yellow seed line imbibed at 8 ºC in either water, saline or osmotic solutions, abscisic acid (ABA), ABA biosynthesis inhibitor, gibberellin (GA4+7), inhibitor of GA biosynthesis and a germination promoter, fusicoccin. Also tested was the effect of seed coat (testa) on seed germination rate and percent germination. Previous studies have established that seed vigor is in part hormonal controlled and genetically controlled. In our study, gene expression was investigated by using transcriptome analysis and hormonal analysis was used to quantitate the changes in hormones and their metabolites during germination. <p> Both the black and the yellow canola seed lines were very sensitive to increasing concentrations of saline and osmotic solutions; however, at the same osmotic potential, osmotic solutions were more inhibitory. The yellow seed line was more sensitive to these conditions than the black seed line. As expected, ABA delayed seed germination, whereas GA4+7 enhanced seed germination and GA4+7 partially overcame the inhibitory effect of ABA. The seed coat was a major factor affecting the germination rate of the yellow seed line; however, GA4+7 overcame the inhibitory effect of the seed coat, whereas ABA exacerbated it. Fusicoccin was more stimulatory to germination than GA4+7; however, unlike GA4+7, it was unable to overcome the inhibitory effect of paclobutrazol, a GA biosynthesis inhibitor. Fluridone, an ABA biosynthesis inhibitor, was unable to overcome the inhibitory effects of a saline solution suggesting that the inhibitory effect was not due to elevated ABA levels. Ethylene, a stimulator of germination, did not appear to be involved in the germination of these two lines. Controlled deterioration at 35 ºC, 85% RH was either partially or completely overcome by exogenous GA4+7. This study demonstrates that the role of hormones, salinity and seed coat on the germination of canola seed under low temperature environmental conditions. <p>During germination, ABA declined while GA4 increased. Higher ABA was found in un-germinated seeds compared to germinated seeds. GA4+7 was lower in seeds imbibed in the saline solution compared to seeds imbibed in water. Un-germinated seeds imbibed in ABA had lower GA4+7 compared to un-germinated seeds imbibed in water; however, the contents of GA4+7 were similar for germinated seeds imbibed in either water or ABA. Phaseic acid (PA) and dihydrophaseic acid (DPA) increased in seeds imbibed in either water, the saline solution or ABA, while they decreased in seeds imbibed in GA4+7. In addition, we found that ABA inhibited GA4 biosynthesis, whereas, GA had no effect on ABA biosynthesis, but altered the ABA catabolic pathway. <p> Gene expression profiles revealed that there are significant differences between un-germinated and germinated seeds. Seeds imbibed in water, GA4+7, a saline solution or ABA had different gene profiles. LEA genes, hormone-related genes, hydrolase-related genes and specific seed germination-related genes were identified and their expression profiles were finely associated with seed germination performance.

Seed vigor, although not well understood, is a key critical component for yield and is in part due to a well establishment and vigorous stand of canola (<i>Brassica napus</i>) seedling under less than ideal conditions in Western Canada. My objective was to determine what constitutes vigor by studying the response of a black seed line and a yellow seed line imbibed at 8 ºC in either water, saline or osmotic solutions, abscisic acid (ABA), ABA biosynthesis inhibitor, gibberellin (GA4+7), inhibitor of GA biosynthesis and a germination promoter, fusicoccin. Also tested was the effect of seed coat (testa) on seed germination rate and percent germination. Previous studies have established that seed vigor is in part hormonal controlled and genetically controlled. In our study, gene expression was investigated by using transcriptome analysis and hormonal analysis was used to quantitate the changes in hormones and their metabolites during germination. <p> Both the black and the yellow canola seed lines were very sensitive to increasing concentrations of saline and osmotic solutions; however, at the same osmotic potential, osmotic solutions were more inhibitory. The yellow seed line was more sensitive to these conditions than the black seed line. As expected, ABA delayed seed germination, whereas GA4+7 enhanced seed germination and GA4+7 partially overcame the inhibitory effect of ABA. The seed coat was a major factor affecting the germination rate of the yellow seed line; however, GA4+7 overcame the inhibitory effect of the seed coat, whereas ABA exacerbated it. Fusicoccin was more stimulatory to germination than GA4+7; however, unlike GA4+7, it was unable to overcome the inhibitory effect of paclobutrazol, a GA biosynthesis inhibitor. Fluridone, an ABA biosynthesis inhibitor, was unable to overcome the inhibitory effects of a saline solution suggesting that the inhibitory effect was not due to elevated ABA levels. Ethylene, a stimulator of germination, did not appear to be involved in the germination of these two lines. Controlled deterioration at 35 ºC, 85% RH was either partially or completely overcome by exogenous GA4+7. This study demonstrates that the role of hormones, salinity and seed coat on the germination of canola seed under low temperature environmental conditions. <p>During germination, ABA declined while GA4 increased. Higher ABA was found in un-germinated seeds compared to germinated seeds. GA4+7 was lower in seeds imbibed in the saline solution compared to seeds imbibed in water. Un-germinated seeds imbibed in ABA had lower GA4+7 compared to un-germinated seeds imbibed in water; however, the contents of GA4+7 were similar for germinated seeds imbibed in either water or ABA. Phaseic acid (PA) and dihydrophaseic acid (DPA) increased in seeds imbibed in either water, the saline solution or ABA, while they decreased in seeds imbibed in GA4+7. In addition, we found that ABA inhibited GA4 biosynthesis, whereas, GA had no effect on ABA biosynthesis, but altered the ABA catabolic pathway. <p> Gene expression profiles revealed that there are significant differences between un-germinated and germinated seeds. Seeds imbibed in water, GA4+7, a saline solution or ABA had different gene profiles. LEA genes, hormone-related genes, hydrolase-related genes and specific seed germination-related genes were identified and their expression profiles were finely associated with seed germination performance.

There is increasing evidence that biological factors (i.e., hormones) support the development of sex differences in behavior by organizing brain systems in prenatal life. However, the behavioral significance of the surge in reproductive steroids that results from the transient activation of the hypothalamic-pituitary-gonadal (HPG) axis around 3-months of age is largely unknown. The goal of the present study was to investigate the role of early postnatal activation of the HPG axis in the development of sex differences in human behavior. Participants included 54 children between 18 and 24 months (32 males and 22 females) and their parents. Infants and their caregivers participated in two, eight minute play sessions that were video-taped and later coded for children’s aggressive behavior and vocal ability. During each session, children wore an actigraph (Actiwatch, Philips Respironics) to provide a nonbiased assessment of activity levels. In addition, toddler’s temperament was measured using the Brief Infant Toddler Social-Emotional Assessment (BITSEA). Saliva samples from each infant were collected at 3-4 months of age and levels of testosterone were measured. Digit ratio levels were also measured at 3-4 months and used as a marker of prenatal androgen levels. The data indicated that boys were more aggressive, engaged in higher levels or activity, and showed less developed language ability. In addition, our results demonstrated that hormone markers associated with higher (i.e., more male-typical) testosterone were related to more aggressive behaviors, higher activity levels, expression of fewer total words, and a shorter duration of time spent vocalizing. A novel finding was that higher testosterone (i.e., more male-typical) levels in early postnatal life predicted less time spent vocalizing, for both sexes together and within males. The present research suggests that hormone levels in early postnatal life may contribute to the development of gender phenotypes, potentially making this a critical period for the development of language and other gender-linked behaviors.

Thesis (M. Phil.)--University of Hong Kong, 2001. / Includes bibliographical references (leaves 67-84).