Choline is known to be essential for brain development and neural function, but its impact on the retina, as a type of neural tissue, is unknown. This study examined the effects of choline during fetal development on membrane phospholipid (PL) compositions and functions in neural tissues, brain and retina. Pregnant C57 BL/6 mice were fed one of the 4 choline modified diets from gestation to early development: i) deficient (Def, 0g/kg), ii) control (Cont, 2.5g/kg), iii) supplemented with choline chloride (Cho, 10g/kg), iv) supplemented with egg phosphatidylcholine (PC) (PC, 10g/kg). On postnatal day (PD) 7, pups were culled to 4 from each dam, and kept on the same respective diets until 45 PD. On PD 35, memory function was measured by Morris water maze and on PD 45, retina function by an electroretinogram. Brain and retina were obtained for PL analysis by 31P NMR. Animals on the Def and PC diets were lower in body weights on PD 7, in comparison to the other two groups. While the Def group caught up in weights to its Cont counterparts, the PC group’s weight stayed consistently low until PD 45 (P<0.03). As for brain function, Cho and PC supplemented groups showed enhanced cued learning task, and spatial memory abilities, respectively, whereas the Def group showed the poorest memory recollection (P<0.05). The ERG amplitudes of rod driven photoreceptors and inner neural cell functions were significant (P<0.05) in the following order: Cont > Def > PC > Cho, at all light intensities, without reaching statistical significances in cone-driven responses. There were no differences in major PL compositions in the brain and retina. PC enriched group had increased subclasses of ether PL, PEaa and PCaa in the brain. These results indicate that while the addition of choline supplementation is beneficial for fetal brain development and function during early developmental stages, its contributions in the retina were minor. The effect of choline to the membrane PL structure was negligible for the stage of development in the given experimental design.

Choline is known to be essential for brain development and neural function, but its impact on the retina, as a type of neural tissue, is unknown. This study examined the effects of choline during fetal development on membrane phospholipid (PL) compositions and functions in neural tissues, brain and retina. Pregnant C57 BL/6 mice were fed one of the 4 choline modified diets from gestation to early development: i) deficient (Def, 0g/kg), ii) control (Cont, 2.5g/kg), iii) supplemented with choline chloride (Cho, 10g/kg), iv) supplemented with egg phosphatidylcholine (PC) (PC, 10g/kg). On postnatal day (PD) 7, pups were culled to 4 from each dam, and kept on the same respective diets until 45 PD. On PD 35, memory function was measured by Morris water maze and on PD 45, retina function by an electroretinogram. Brain and retina were obtained for PL analysis by 31P NMR. Animals on the Def and PC diets were lower in body weights on PD 7, in comparison to the other two groups. While the Def group caught up in weights to its Cont counterparts, the PC group’s weight stayed consistently low until PD 45 (P<0.03). As for brain function, Cho and PC supplemented groups showed enhanced cued learning task, and spatial memory abilities, respectively, whereas the Def group showed the poorest memory recollection (P<0.05). The ERG amplitudes of rod driven photoreceptors and inner neural cell functions were significant (P<0.05) in the following order: Cont > Def > PC > Cho, at all light intensities, without reaching statistical significances in cone-driven responses. There were no differences in major PL compositions in the brain and retina. PC enriched group had increased subclasses of ether PL, PEaa and PCaa in the brain. These results indicate that while the addition of choline supplementation is beneficial for fetal brain development and function during early developmental stages, its contributions in the retina were minor. The effect of choline to the membrane PL structure was negligible for the stage of development in the given experimental design.

Siekiant nustatyti genetinius, fiziologinius ir fizinius veiksnius, darančius įtaką dygliuotojo šaltalankio (Hippophae rhamnoides L.) auginių rizogenezei, tirti trijų veislių žalieji auginiai, paimti iš ūglių lignifikacijos pradžioje. Nustatyta, kad ISR 40 ir 50 mg/l koncentracijos tirpalas, palyginus su kontroliniu variantu, nežymiai, bet patikimai spartina rizogenezės procesą. Net mažiausios NAR koncentracijos mažina auginių su šaknimis išeigą. IAR rizogenezės spartos nedidina, bet 40–50 mg/l koncentracijų tirpalai didina įsišaknijusių auginių procentą. ISR ir NAR poveikyje nežymiai didėja vidutinis pagrindinių šaknų skaičius ant šaknies regeneruojančio auginio. Intensyviausiai šaknis regeneruoja iš ūglio viršūnės paimti auginiai, kuriems būdingas mažiausias sumedėjimo lygis. Auginiai nuo juvenaliniame tarpsnyje esančių medžių pagal rizogenezės spartą atsilieka nuo auginių, paimtų nuo derančių medžių. Esminę įtaką dygliuotojo šaltalankio žaliųjų auginių rizogenezei daro auginio ilgis. Parodyta, kad egzistuoja minimalūs auginio, turinčio potencijų rizogenezei, parametrai. Tik pavieniai penkių centimetrų ilgio auginiai regeneruoja šaknis. Didėjant auginio ilgiui rizogenezės dažnumas didėja. / In order to evaluate genetic, physiologic and physical factors influencing rhizogenesis of green cuttings of sea buckthorn, cuttings from three cultivars were taken at the beginning of lignification. It was estimated, that 40 and 50 mg/L IBA solutions narrowly but reliably quicken rhizogenesis compared to control. Solution with even the lowest NAA concentration reduces output of cuttings with roots. IAA doesn’t accelerate process of rhizogenesis, but 40 and 50 mg/L IAA solutions increase percentage of rooted cuttings. Average main root quantity on the rooted cutting increases under the influence of IBA and NAA. Cuttings with the lowest lignification level, which were taken from terminal shoot part, regenerated roots more intensively. Cuttings taken from juvenile plants lag behind the cuttings from bearings plants according to rhizogenesis speed. The length of cutting is crucial for the rhizogenesis of sea buckthorn cuttings. Minimal cutting parameters for potential rhizogenesis are shown. Only several 5 cm length cuttings regenerate roots, rate of rhizogenesis increases in longer cuttings.

Mémoire numérisé par la Division de la gestion de documents et des archives de l'Université de Montréal.

L’objectif de ce travail de thèse vise à analyser les effets de quelques pesticides et d’un adjuvant sur des organismes marins, représentatifs de quatre niveaux trophiques, à savoir des micro-algues, un échinoderme, des bivalves et un poisson. L’analyse de la pollu-sensibilité est basée sur l’utilisation de différents bio-essais existants ou adaptés au contexte de cette étude.Les tests de toxicité ont permis d’évaluer la sensibilité de trois espèces phytoplanctoniques (Chaetoceros calcitrans, Isochrysis aff. Galbana et Tetraselmis suecica) vis-à-vis d’un fongicide l’époxiconazole (pur et en formulation commerciale Opus) et de l’adjuvant nonylphénol. D’une manière générale, la croissance de C. calcitrans et I. aff. Galbana s’avère plus sensible à l’action des contaminants étudiés. Ainsi, en utilisant pour C. calcitrans un milieu reproduisant les conditions naturelles du Golfe de Gabès, des valeurs de CE50 de 2 ,31 mg/L et 2,9 μg/l sont obtenues respectivement avec la substance active époxiconazole, et le produit formulé. Ces résultats montrent l’importance des adjuvants dans la toxicité et que les micro-algues peuvent être sensibles aux effets non-cibles d’un fongicide triazole.En outre, l’âge des cellules, les conditions d’éclairement et de composition des milieux de culture induisent des changements de sensibilité au fongicide, suggérant que la densité cellulaire est un paramètre important dans les tests de toxicité.L’analyse de quelques paramètres physiologiques montre que les contaminants utilisés induisent une augmentation du volume cellulaire, des échanges gazeux, de la teneur en pigments et en ATP. Il apparaît ainsi que les toxiques utilisés réduisent la vitesse de croissance, prolongeant le cycle cellulaire, sans affecter la production de nouveaux matériaux, nécessaires à la construction de nouvelles cellules.Par ailleurs, une étude réalisée en microcosmes lors d’un bloom de l’algue toxique Karenia selliformis dans le golfe de Gabès, montre que les différents contaminants chimiques (époxiconazole, chlorpyriphos-éthyl, nonylphénol) produisent des modifications drastiques de la structure des communautés phytoplanctoniques, fonction de la nature et de la concentration du contaminant.La toxicité des différents contaminants a été étudiée sur des animaux marins, aux stades embryo-larvaire (oursin, huître, palourde), métamorphose des larves (palourde) et survie des larves (turbot). Les résultats montrent que les larves du turbot sont les plus sensibles à l’action des contaminants avec des CE50 allant de 2,78 à 492 μg/L selon le toxique et que chez la palourde, la métamorphose est le stade le plus sensible parmi les trois stades de développement étudiés. Les contaminants utilisés produisent des anomalies du développement et des malformations embryonnaires qui peuvent induire une réduction de la production naturelle en agissant i) directement sur le développement embryo-larvaire et ii) indirectement sur la qualité et la biodisponibilité de l’aliment à travers la variation de la biomasse phytoplanctonique. Ces résultats soulignent la nécessité d’appliquer les toxiques à différents organismes marins présentant des organisations différentes pour apprécier pleinement leur impact. / This work aims to study the effects of a few pesticides and one adjuvant on marine organisms, representatives of four trophic levels : micro-algae, echinoderm, bivalves and fish. Analysis of the pollu-sensitivity was based on the utilisation of existing bio-assays or adapted to this study.Phytotoxic assessments were conducted on three phytoplanktonic species (Chaetoceros calcitrans, Isochrysis aff. Galbana et Tetraselmis suecica) using the fungicide epoxiconazole and the adjuvant nonylphenol. Sensitivity to these toxicants of C. calcitrans and I. aff. Galbana was high. Thus, when C. calcitrans was grown in a medium simulating pre-winter conditions in Gabès Gulf, EC50 values were respectively, 2.31 mg/L and 2.9 μg/L for epoxiconazole active ingredient and epoxiconazole-formulated. These results questioned the use of ecotoxicological data obtained solely using active molecules of pesticides rather the complete formulation and show that non-target micro-algae may be affected by a triazole fungicide.Moreover, cell age, light and nutrient composition induced changes in epoxiconazole sensitivity, suggesting that cellular density is an important parameter in toxicity tests.Analysis of a few physiological parameters show that contaminants used in this study induce an increase of pigment content, ATP synthesis, and rates of oxygen exchanges while the cell volume enlarges. Consequently, the toxicants might reduce the growth rate, by a prolongation of the cell cycle without affecting the production of new material for the construction of new cells.Bioassays were conducted using microcosms during a bloom of the toxic algae Karenia selliformis in the Gulf of Gabès. The different toxicants (epoxiconazole, chlorpyrifos-éthyl, nonyphenol) produced drastic changes in the phytoplankton communities, depending on the type and concentration of the contaminant.Phytotoxic assessments were conducted on marine animal models, using different developmental stages: embryo-larval development (sea urchin, oyster, and clam), metamorphosis larvae (clam) and larvae survival (turbot). Results show that turbot larvae are most sensitive to the action of contaminants with EC50 values ranging from 2.78 to 492 μg/L depending on the toxic and that the metamorphosis is the stage the most sensitive of the three stages of development of clam studied.The pollutants produced developmental and embryonic abnormalities that might induce a reduction in the natural production by acting i) directly on the development of the marine organisms and ii) indirectly on the quality and bioavailability of food through the variation of phytoplankton biomass.These results underline the need to study pollutant effects on marine organisms having different organizations to evaluate their full impact.

Mémoire numérisé par la Division de la gestion de documents et des archives de l'Université de Montréal

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Det blir allt enklare att starta ett företag i Sverige, mycket tack vare de många startupplattformar som finns. Samtidigt överlever knappt hälften av alla startup längre än fem år. En viktig aspekt för att inte misslyckas som nystartat företag är att förstå sina kunder och sina användare och lansera produkten till rätt kundsegment, samtidigt som det kan vara kostsamma undersökningar som också förlänger den kritiska tiden innan företaget börjar generera inkomster. För att det ska bli lönsamt krävs det också att företagen förstår hur informationen som insamlas ska användas för att förbättra produkten. Det här arbetet undersöker hur och när startups väljer att involvera sina användare i produktutvecklingsprocessen. För att besvara arbetets frågeställningar har en litteraturstudie utförts, där bakgrunden till problematiseringen kartlagts. Därefter genomfördes en intervjustudie med fyra olika startups där syftet var att förstå hur arbetet med användarinvolveringen utfördes i praktiken. Samtliga företag som intervjuades hade genomgått ett program på, eller finansierats av någon startupplattform. Studien visade att startups ofta inte följer en linjär produktutvecklingsprocess, utan måste anpassa den efter de finansiella och strukturella förutsättningar som företaget har. Därför lämpar sig ofta andra iterativa metoder för företagen, där insatsen för varje förändring blir mindre. Det gäller också för användarinvolvering, där företagen dock strävar efter att involvera användaren så mycket som möjligt då det upplevs som en minskad osäkerhet. En kontinuerlig involvering av användare är dock sällan genomförbart för nystartade företag. Dessutom gör bristen på erfarenhet det svårt för företagen att strukturerat fastställa de viktigaste kraven och behoven från användarna. Sammanfattningsvis pekar studiens resultat på att en utmaning för startups är att applicera en linjär produktutvecklingsprocessen på grund av bristande struktur och startupfas. De strävar efter att förstå sina kunder och användare då konsensus råder om att detta leder till en lyckad lansering då osäkerheten minskar och produkterna förbättras. / Starting a business in Sweden is becoming easier, thanks in large part to the numerous startup platforms available. However, barely half of all startups survive beyond the first five years. A crucial aspect of avoiding failure as a new company is understanding one's customers and users and launching the product to the right customer segments. Yet, conducting costly surveys can also prolong the critical period before the company starts generating income. To make it profitable, companies also need to understand how the collected information should be used to improve the product. This study investigates how and when startups choose to involve their users in the product development process. To address the research questions, a literature review was conducted mapping out the background of the problem. Then an interview study was carried out with four different startups, aiming to understand how user involvement was implemented in practice. All interviewed companies had gone through a program on or were funded by a startup platform. The study revealed that startups often do not follow a conventional product development process but have to adapt it based on the company's financial and structural conditions. Insted, other iterative methods are often suitable for new companies, where the cost for each change is less significant. This also applies to user involvement, although companies strive to involve users as much as possible because it is perceived as reducing uncertainty. However, continuous user involvement is rarely possible for startups with limited budgets and time constraints. Moreover, the lack of experience makes it challenging for companies to systematically determine the most critical requirements and needs from users. In summary, the study's findings indicate that a challenge for startups is to apply a linear product development process due to a lack of structure and the startup phase. They strive to understand their customers and users, as there is a consensus that this leads to a successful launch by reducing uncertainty and improving products.