Yellow pigment (YP) concentration is an important quality trait in durum wheat (<i>Triticum turgidum</i> L. var <i>durum</i>) and is comprised primarily of carotenoids. The main objective of our study was to measure the accumulation of carotenoids during the grain fill period to improve our understanding of the physiological basis for differences among durum wheat cultivars. Thirteen cultivars and breeding genotypes with large variation in total YP concentration (<6 µg g-1 to >15 µg g-1) were studied. Spikes were sampled from replicated field plots in 2007 and 2008 near Saskatoon and Swift Current, Saskatchewan, Canada, at 14, 21, 28 and 35 days after heading (DAH). The remainder of each plot was combined at grain maturity for YP and carotenoid analysis. Carotenoids were extracted with 1:1 methanol:dichloromethane (0.1% BHT) and quantified with HPLC. <i>Trans</i> (E)-lutein was the predominant carotenoid at maturity and was detected at 14 DAH in all genotypes. The rate and duration of E-lutein accumulation was variable among genotypes expressing high, intermediate and low YP. The accumulation of all carotenoids was lowest in genotypes expressing low YP, and suggests rate limitations early in the carotenoid biosynthetic pathway. E-zeaxanthin concentrations were highest in mature grain, but no significant differences were detected among genotypes. However, the ratio of E-zeaxanthin to E-lutein was inversely correlated with total YP, suggesting that the â,å branch of lycopene cyclization is favoured over the â,â branch in high-YP genotypes. These results provide insights to the regulation of the carotenoid biosynthetic pathway during grain fill stage in durum wheat and will facilitate breeding for higher carotenoid concentration.

The objectives of this study are to know the behavioural response of the hagfish, Paramyxine cheni to light and to find out if various parts of hagfish¡¦s body differ in sensitivity to light. Photosensitivity was measured in terms of time lapsed between light on and initiation of behavioural sequence (i.e., the reactive time). Behavioral response was measured by the persistent time from the beginning and ending of the behavioural sequence. Five types of light were used as the stimuli to the whole animal: green light, blue light, yellow light, red light, and white light. The lineup of sensitivity for various wavelengths in increasing reactive times( ranging from 13 seconds to 180 seconds) is: green light, blue light, white light, yellow light, red light. Red light significantly differed from the other four types of light in the reactive time; the hagfish was significantly less sensitive to this red light. Four regions of the body were tested with white light: head, gill aperture, tail and mid-portion between the first gill aperture to cloaca. In addition, two parts of the body were simultaneous tested with stimulate: head and tail (HT). The lineup of sensitivity of various regions of body for increasing reactive times (ranging from 9 seconds to 1200 seconds) is: tail, head, mid-portion between the first gill aperture to cloaca, and gill aperture. Tail was significantly more sensitive than the other three parts of the body. However, sensitivity for HT was significantly higher than the tail. Hagfish¡¦s spontaneous movement (i.e., under dark condition)included a number of behavioural sequences differed in the arrangement of behavior patterns (i.e., rolling, swimming, wiggling, springing, and pause). ¡¥Rolling¡¦ was the most preferred initial pattern in a spontaneous movement sequence. In contrast, illumination on tail evoked a complex motor response. Thus, such response was considered not a simple reflex, but a select of choice. ¡¥Swimming¡¦, on the other hand, is the most preferred initial pattern in the sequence triggered by photo stimulation on the tail. According to fluoresence histochemistry study the rhodopsin-like protein is present in the large oval-shaped cells distributed in the epidermis of hagfish. the number and the size of photo-sensitive cells on the tail and gill aperture and the fluorescence intensity on the tail were significantly higher than that on the gill aperture region.

Age related macular degeneration (AMD) is the most common cause of irreversible vision loss in the elderly. At present, there are an estimated one million people in Canada with some form of AMD and this number is expected to double to two million by 2031. These estimates are sobering, and it is predicted that costs for treatment and care of individuals who suffer vision loss from AMD will have significant impact on the social and public health systems in Canada in the next two decades. There are treatments to slow the progression of vision loss, but unfortunately, there are currently no cures available for AMD. In order to develop effective second generation therapies and cures, further insights into how and why AMD develops are greatly needed. Recent studies have provided novel insights into the role of inflammation in the pathogenesis of AMD. Inflammation, or swelling of the retinal tissues, causes harmful processes that promote macular degeneration. The proposed studies will focus on the triggers of inflammation in the retina. It is hypothesized that macular degeneration may be slowed or stopped by eliminating the molecules that cause inflammation in the retina. This study will focus on amyloid beta (Aβ), a toxic molecule that has been implicated in retinal inflammation, and the role that it may play in gene expression of the retinal pigment epithelial cell. Amyloid beta is a well studied peptide in another age related disorder, Alzheimer’s disease. It is the major extracellular deposit in Alzheimer’s disease plaques, and has recently been discovered as a component of drusen, the hallmark extracellular deposits in the retina of patients with the ‘dry’ form of AMD. These studies will allow the development of new treatment regimens that target retinal inflammation and thus minimize the processes that ‘trigger’ the onset of macular degeneration.

Each day, we are confronted with a large amount of more or less important information that we have to consider, and even in our digital society we need paper for communication, documentation and education. Much of the paper we use or are confronted by in our daily life, such as newspapers, books and packages, contains printed images or texts, and the appearance of both the print and the supporting surface is important. A good contrast between a printed text and the paper makes it easier to read, a detailed print of an illustration makes it more informative, and clear and evenly distributed colours on a package or on a poster make it more appealing. All of these qualities depend on the optical properties of the paper product and the the behavior of light illuminating the different materials. The aim of the work described in this thesis is to characterize the structure of coatings and prints, and to validate models for the optical response and interaction of ink and coating based on optical measurements of physical samples. It is the interactions between the printing ink and the porous structure of the coating layers that are subject to investigation. Experiments have been employed to relate the physical conditions in a flexographic printing nip to the ink setting, affected by the physical and chemical properties of the coating, to the resulting optical response of the printed paperboard. / The aim of the work described in this thesis is to characterize the structure of coatings and prints, and to validate models for the optical response and interaction of ink and coating based on optical measurements of physical samples. It is the interactions between the printing ink and the porous structure of the coating layers that are subject to investigation. Experiments have been employed to relate the physical conditions in a flexographic printing nip to the ink setting and the resulting optical response. By comparing simulated and measured results, it was shown that modifications of the surface properties account for the brightness decrease when substrates are calendered. Light scattering simulations, taking into account the surface micro-roughness and the increase in the effective refractive index, showed that surface modifications accounted for most of the observed brightness decrease, whereas the bulk light scattering and light absorption coefficients were not affected by calendering. Ink penetration affects the print density, mottling and dot gain. Results show that ink distribution is strongly affected by surface roughness, differences in pore size and pore size distribution. For samples having different latex amounts and different latex particle sizes, a higher print force did not increase the depth of penetrated ink to any great extent, but rather allowed the wetting to act more efficiently with a more evenly distributed ink film, a higher print density and fewer uncovered areas as a result. Uncovered areas could be linked both to local roughness variations and to local wettability variations on the surface. Samples with different ratios of calcium carbonate/kaolin clay pigment showed an increased porosity and an increase in print density with increasing amount of kaolin in the coating layer.

No description available.

Thesis (Ph. D.)--University of Virginia, 1999. / Spine title: Structure - function analysis of IRBP. Includes bibliographical references (p. 167-172). Also available online through Digital Dissertations.

Stuttgart, Univ., Diss., 2000.

Regensburg, Univ., Diss., 2008.

Muitos vertebrados ectotérmicos ajustam suas cores corporais para serem confundidos com o ambiente, através da migração de pigmentos no interior de cromatóforos, regulada por sistemas neurais e/ou hormonais. Essas mudanças de coloração auxiliam no mimetismo, termorregulação, comunicação social e expressão de comportamentos como excitação sexual, agressividade e medo. Entretanto, cromatóforos de inúmeras espécies respondem diretamente à luz. Estudos sobre a resposta à luz nos melanóforos de Xenopus laevis levaram à descoberta do fotopigmento melanopsina, uma opsina que está presente na retina de todos os grupos de vertebrados, inclusive no homem. Vários hormônios podem regular o processo de mudança de cor nos vertebrados, dentre eles a melatonina, hormônio secretado pela glândula pineal. Este é o principal órgão responsável pela integração do sistema neuroendócrino dos vertebrados ao meio ambiente, traduzindo direta ou indiretamente a informação do fotoperíodo em sinal hormonal, coordenando assim os ritmos fisiológicos circadianos com o meio ambiente. Os objetivos deste trabalho foram: investigar se a expressão gênica das melanopsinas e do receptor de melatonina em melanóforos de Xenopus laevis apresenta variação temporal sob diferentes condições luminosas; verificar se a expressão gênica das melanopsinas e do receptor de melatonina em melanóforos de Xenopus laevis pode ser modulada por melatonina. Dados do trabalho demonstram que as melanopsinas em melanóforos de Xenopus laevis são sincronizadas aos ciclos de claro-escuro, expressando um robusto ritmo ultradiano com período de 16h para Opn4m e um ritmo circadiano com período de 25h para Opn4x. Curiosamente, essa ritmicidade só foi observada quando os melanóforos foram mantidos em ciclos 12C:12E e foram submetidos à troca de meio durante a fase clara do fotoperíodo. A constância na expressão gênica do receptor de melatonina Mel1, quer sob diferentes regimes de luz, quer sob tratamento por melatonina, sugere que esse gene é extremamente estável, não sofrendo alterações ao ser submetido a estímulos exógenos, podendo ser considerado um gene constitutivo. O tratamento com melatonina por 6h na fase clara do fotoperíodo, além de inibir drasticamente a expressão de Opn4x e Opn4m, aboliu a ritimicidade de ambas as melanopsinas. Nossos resultados indicam que os melanóforos de Xenopus laevis possuem um relógio funcional e podem ser caracterizados como relógios periféricos, porém necessitam do ciclo claro-escuro associado à troca de meio para exibirem sua sincronização. / Many ectothermic vertebrates adjust their body color to mimic the environment, through the pigment migration within chromatophores, regulated by neural and / or hormonal systems. These changes in color help in camouflage, thermoregulation, social communication and behaviors such as sexual arousal, agressiveness and fear. However, chromatophores of several species respond directly to light. Studies about light response in melanophores of Xenopus laevis have led to the discovery of the photopigment melanopsin, an opsin that is present in the retina of all vertebrate groups, including man. Various hormones may regulate the process of color change in vertebrates, among them melatonin, hormone secreted by the pineal gland. This is the main organ responsible for the integration of the neuroendocrine system of vertebrates to the environment, translating directly or indirectly the photoperiod information into hormonal signal, thus coordinating physiological circadian rhythms with the environment. The objectives of this work were: to investigate whether the gene expression of melanopsins and melatonin receptor in melanophores of Xenopus laevis exhibited temporal variation under different light conditions; to verify whether gene expression of melanopsins and melatonin receptor in melanophores of Xenopus laevis could be modulated by melatonin. Our data show that melanopsins in melanophores of Xenopus laevis are synchronized to light-dark cycles, expressing a robust ultradian rhythm with a period of 16h for Opn4m and circadian rhythm with a period of 25h for Opn4x. Interestingly, the rhythm was only observed when the melanophores were maintained in 12L: 12D regime and medium change was performed during the fotophase of photoperiod. The constancy in the expression of melatonin receptor Mel1c, either under different light regimes, or under treatment by melatonin, suggesting that this gene is extremely stable, not being altered by exogenous stimulus, and may be considered a constitutive gene. Treatment with melatonin for 6h during the fotophase of the photoperiod, drastically inhibit the expression of Opn4x and Opn4m, and abolished the rhythm of both melanopsins. Our results indicate that melanophores of Xenopus laevis possess a functional clock and can be characterized as peripheral clocks, but they need the light-dark cycle associated with change of medium to exhibit their synchronization.

Os relógios biológicos são fundamentais para a sincronização do comportamento dos organismos a mudanças no fotoperíodo. Todas as alterações rítmicas são determinantes para a sobrevivência da espécie uma vez que elas prevêem que os ajustes internos coincidam com a fase mais propícia do ciclo ambiental, permitindo aos organismos a capacidade de sincronizar esses eventos internos com os ciclos ambientais. Muitos desses ritmos biológicos são claramente associados ao ciclo claro-escuro, sendo este ciclo de grande importância para as espécies que possuem algum tipo de pigmento fotossensível. Os melanóforos de Xenopus laevis são fotossensíveis, respondendo à luz com dispersão dos grânulos de melanina, devido à presença de duas melanopsinas, Opn4x e Opn4m. As células pigmentares dos vertebrados heterotérmicos respondem com migração pigmentar a uma variedade de agentes, incluindo as endotelinas. Em peixes teleósteos, ETs induzem a agregação pigmentar em melanóforos, enquanto que em anfíbios, ET-3 induz a dispersão de grânulos de pigmentos em melanóforos de Xenopus laevis e de Rana catesbeiana, através da ativação de receptores ETc. Propusemos determinar o padrão temporal de expressão dos genes das melanopsinas e do receptor ETc em melanóforos dérmicos de X. laevis em cultura, bem como os efeitos temporais e dose- dependentes da endotelina sobre essa expressão. Demonstramos, através de ensaios de PCR quantitativo, que o tratamento de 12C:12E , somado a uma troca de meio, assim como o de endotelina-3 10-9 e 10-8M em escuro constante, foi capaz de sincronizar a expressão de Opn4x e Opn4m. Entretanto, o receptor ETc parece não ser sincronizado pelo ciclo claro-escuro, ou pelo tratamento hormonal. Dependendo da dose utilizada e do ZT analisado, ET-3 pode promover um aumento ou inibição da expressão gênica de Opn4x, Opn4m e ETc, indicando uma modulação de forma dose-dependente. Além disso, pode atuar como um agente sincronizador da expressão dos transcritos das melanopsinas. / The biological clocks are critical for synchronizing the behavior of organisms to changes in photoperiod. All rhythmic changes are crucial to the survival of the species since they provide for internal adjustments to coincide with the phase of the cycle most favorable. Many of these biological rhythms are clearly associated with the light-dark cycle, of major importance for species that have some type of photosensitive pigment. Melanophores of Xenopus laevis are photosensitive, responding to light with dispersion of melanin granules, due to the presence of two melanopsins, Opn4x and Opn4m. The pigment cells of ectothermic vertebrates respond with pigment migration to a variety of agents including the endothelins. In teleost fish, ETs induce pigment aggregation in melanophores, whereas in amphibians, ET-3 induces the dispersion of pigment granules in melanophores of Xenopus laevis and Rana catesbeiana, by activation of ETc. We proposed to determine the temporal pattern of gene expression of the ETc receptor and melanopsins in dermal melanophores of X. laevis in culture as well as the effects of endothelin-3 on the temporal expression of the 3 genes. Using quantitative PCR, we demonstrated that 12L: 12D regimen, combined with medium changes, as well as the treatment with 10-9 and 10-8M endothelin-3, was able to synchronize the expression of Opn4x and Opn4m. However, ETc receptor seems not to be synchronized by light-dark cycle, or hormone treatment. Depending on the dose and the ZT, ET-3 may promote an increase or inhibition of gene expression of Opn4x, Opn4m and ETc, indicating a dose-dependent modulatory effect. In addition, endothelin-3 may also act as a synchronizing agent of the melanopsins transcripts.