Characterisation of adhesion of a probiotic bacterium Lactobacillus rhamnosus HN001 to extracellular matrix proteins and the intestinal cell line Caco-2 : a thesis presented to Massey University in partial fulfilment of the requirement for the degree of Master of Science in Microbiology

This study focuses on Lactobacillus rhamnosus HN001, a potential candidate for use as a probiotic. Probiotics are microorganisms that can exert a beneficial effect on a host. It is believed that the ability of a probiotic to colonise gastrointestinal surfaces is important in its ability to exert a beneficial effect on the host. In order to do so, it is thought the microorganism must be able to adhere to molecules found on intestinal cells. HN001 has been shown to adhere to human intestinal cell lines (Gopal et al., 2001). This study characterises the molecular species involved in the adherence of HN001 to intestinal molecules and cell lines, which may be important in the ability of HN001 to exert health benefits in a host. Both liquid and solid-phase binding assays were used to characterise HN001 binding to extracellular matrix (ECM) components found in intestinal tissues. Of the ECM components investigated, HN001 bound fibronectin with the highest affinity. This interaction was specific, saturable and dependent on the growth phase of HN001. HN001 bound immobilised fibronectin in preference to soluble fibronectin through a protein-dependent interaction. HN001 was also found to bind to the N-terminal heparin binding domain of fibronectin and the C-terminal part of the first type III repeat in the fibronectin molecule (III1-C). HN001 adhered to the human intestinal cell line, Caco-2, in a dose-dependent manner that was enhanced by a pH-sensitivc factor present in the spent culture supernatant. Since fibronectin-binding was identified as a possible mechanism for adherence of HN001 to intestinal tissues, HN001 genome DNA sequence was examined for genes encoding putative fibronectin-binding proteins. Fbl (Fibronectin-binding like) was identified through its similarity to fibronectin-binding proteins from Streptococcus pneumoniae (Holmes et al., 2001) and S. pyogenes (Courtney et al., 1994). Fbl was expressed by a GST fusion system and used to compete with HN001 adhesion in liquid-phase binding assays to ascertain its function. Since difficulties were experienced when expressing and purifying soluble Fbl, an insertional disruption of the fbl gene was created and its phenotype investigated in liquid-phase, solid-phase and Caco-2 binding assays to determine Fbl function

Silicon crystals: Process for manufacturing wafer-like silicon crystals with a columnar structure

Wafer-like crystals suitable for making solar cells are formed by pouring molten Si containing suitable dopants into a mold of the desired shape and allowing it to solidify in a temperature gradient, whereby the large surface of the melt in contact with the mold is kept at less than 200 D and the free surface is kept at a temperature of 200-1000 D higher, but below the melting point of Si. The mold can also be made in the form of a slit, whereby the 2 sides of the mold are kept at different temperatures. A mold was milled in the surface of a cylindrical graphite block 200 mm in diameter. The granite block was induction heated and the bottom of the mold was cooled by means of a water-cooled Cu plate, so that the surface of the mold in contact with one of the largest surfaces of the melt was held at approximately 800 D. The free surface of the melt was subjected to thermal radiation from a graphite plate located 2 mm from the surface and heated to 1500 D. The Si crystal formed after slow cooling to room temperature had a columnar structure and was cut with a diamond saw into wafers approximately 500 mm thick. Solar cells prepared from these wafers had efficiencies of 10 to 11%

Novel silicon crystals and method for their preparation

Plate shaped silicon crystals and their preparation by pouring a silicon melt into a suitable mold and then allowing it to solidify in a temperature gradient were investigated. The production of energy by direct conversion of solar energy into electrical energy by means of solar cells takes on increasing importance. While this type of energy production is already the prevailing form today in the realm of satellite technology, its terrestrial application has thus far encountered strict limitations owing to the high price of such solar cells. Of the greatest interest in this connection are silicon cells. A substantial reduction in the semiconductor material costs and the costs involved in the further processing to make solar cells are prerequisites for a rational market growth for solar energy

French adverbial clauses: rescue by ellipsis and the truncation vs. intervention debate

This paper investigates the restrictions on movement to the left periphery found in non-root environments such as French central adverbial clauses and argues that an analysis of main clause phenomena based on intervention/Relativized Minimality is to be preferred to one based on structural truncation. The empirical basis for this claim consists of an examination of some asymmetries between French infinitival TP ellipsis and infinitival TP Topicalization. Adopting Authier's (2011) approach to TP ellipsis whereby the to-be-elided TP undergoes fronting in the computational component but fails to be spelled out at PF, we argue that these asymmetries follow from the fact that in French, while a spelled out fronted TP is an intervener for wh-movement in adverbial clauses, leading to a PF crash, the ellipsis of this fronted TP leads to a convergent derivation via Boskovic's (2011) mechanism of "rescue by PF deletion." This account entails that adverbial clauses involve wh-movement (Haegeman 2006, among others) and that the landing site for TP Topicalization is available in a non-root environment, two conclusions that militate against the hypothesis that non-root clauses have an impoverished left periphery

De l'expertise disciplinaire aux savoirs à enseigner

Titre de l'écran-titre (visionné le 23 avril 2009).Bibliogr.Compte rendu d'une démarche d'intégration d'un cadre de référence didactique réalisée par une enseignante en soins infirmiers dans un contexte de mentorat au collégial; mise en relief du soutien offert par la personne-ressource aux différents moments de cette intégration

Applications of polyoxometalates in medicine and their putative mechanisms of action

Relatório de Estágio de Licenciatura, Bioquímica, Faculdade de Ciências e Tecnologias da Universidade do Algarve, 2015Polyoxometalates (POMs) are inorganic metal-oxide assemblies presenting a wide range of possible structure, size and metal-combination, as well as a high solubility in water and large redox chemistry. These properties are of a great interest in medicine and polyoxometalates are investigated to produce inorganic-drugs against virus, bacteria and tumour cells. Results showed that POMs, such as the PM-8 ([NH3Pr]6[Mo7O24]•3H2O) induced inhibition of tumour cell proliferation, whereas others POMs inhibit DNA- or RNA-virus activation or bacterial growth. While the mechanisms of action of the anti-viral and –bacterial activities are quite well understood, the same does not go for the anti-tumour activity. Nevertheless, the inhibition of tumour proliferation seems to be correlated with the inhibition of certain enzymes such as histone deacetylases and ecto-nucleotidases, or with the programmed death, apoptosis. In this report, these several hypothesis were approach, in a way to explain the anti-tumour, -bacterial and -viral activities of some polyoxometales, but nothing as yet been concluded and further studies are needed for a better understading.Os polioxometalates (POMs) são complexos inorgânicos constituídos por óxido de metais que apresentam uma grande variedade de estrutura, tamanho e combinações de metais, assim como uma grande solubilidade em meio aquoso e numerosas reações de redox. Estas propriedades são de grande interesse na medicina e os polioxometalates são estudados para desenvolver drogas eficazes contra vírus, bactérias e tumores. Os resultados mostraram que alguns POMs, tal como o PM-8 ([NH3Pr]6[Mo7O24] •3H2O) , podiam provocar a inibição de proliferações tumorais, enquanto que outros inibiam a activação de DNA/RNA virais ou ainda, o crescimento bacteriano. Embora os mecanismos de ação da actividade antiviral e antibacteriana serem bem conhecidos, não podemos dizer o mesmo da actividade anti-tumoral. Pórem, a inhibição da proliferação tumoral parece ser correlacionada com a inibição de enzimas, tais como as histone deacetilases e as ecto-nucleatidase, ou com a morte programada chamada apoptose. Neste trabalho, várias hipóteses foram abordadas para poder determinar as actividades anti-tumoural, -bacteriana e -viral de certos polioxometalates, mas nada ainda foi concluído e estudos adicionais são necessários para uma melhor compreensã

Ellipsis as Movement and Silence: Evidence from French

French allows ellipsis after a number of verbs that express priority or dynamic modality. This phenomenon is known as ‘modal ellipsis’ and, in the past ten years, its syntactic status has been hotly debated in the literature on Romance syntax in ways reminiscent of the controversy surrounding the proper syntactic treatment of English VP ellipsis and Sluicing that started with the early works of Ross (1967) and Sag (1976). What has been established so far with some degree of certainty is that unlike English VP-ellipsis, French modal ellipsis is ellipsis of a TP (Dagnac, 2010). Also established by Busquets and Denis (2001) is the fact that modal ellipsis allow syntactic extraction out of the elision site. This weighs heavily in favor of a PF-deletion approach because it suggests that the ellipsis site has inner structure and therefore provides an extraction site that would remain unavailable under a pro-form approach. In this paper, I explore a novel formulation of the licensing conditions on modal ellipsis that takes as a point of departure a suggestion by Johnson (2001) that English VP-Ellipsis should be derived by way of movement and that elided VPs stand in a topic position though they are not spelled out at PF. I argue that adopting a similar approach to French modal ellipsis correctly predicts (a) the class of French verbs that license modal ellipsis, (b) some novel grammaticality contrasts involving infinitival forms of these verbs, and (c) the fact that French does not have VP-Ellipsis and that English does not have modal ellipsis

The Transition from disciplinary expertise to curricular knowledge : an essential step in the acquisition of didactic competency

Titre de l'écran-titre (visionné le 6 mai 2009).Bibliogr.Compte rendu d'une démarche d'intégration d'un cadre de référence didactique réalisée par une enseignante en soins infirmiers dans un contexte de mentorat au collégial; mise en relief du soutien offert par la personne-ressource aux différents moments de cette intégration

Groupes a un paramètre opérant dans le domaine minimal d'un opérateur différentiel

RésuméDans ce travail on cherche à cerner les limites de la méthode des quotients différentiels, ou méthode de Nirenberg (cf. [6, 7]), dans l'étude de la régularité des solutions de problèmes de Dirichlet variationnels, non nécessairement elliptiques. Pour celà on remplace le groupe des translations par un groupe de difféomorphismes à un paramètre, arbitraire, la dérivation par le champs de vecteurs associé, les opérateurs elliptiques par des itérés d'opérateurs de type principal. On obtient une condition nécessaire et suffisante, assez restrictive, sur les champs de vecteurs de laquelle on tire des résultats positifs et négatifs concernant la régularité des solutions des problèmes de Dirichlet associés