Linker histone H1 associates with nucleosomes, facilitating folding and packaging of DNA into higher order chromatin structure. With 11 variants in mammals, histone H1 is the most divergent histone class. Histone H1 variants are differentially expressed during development and cellular differentiation, and regulate specific gene expression in vivo. Ample studies have established the role of linker histone H1 in chromatin compaction and gene expression regulation; however, its role in diseases, such as cancer, remain understudied. In this study, we explore the role of H1 in ovarian cancer, one of the most devastating gynecological cancers due to its poor prognosis and difficulty in early diagnosis. Although mutations of genes responsible for cell proliferation, differentiation and survival have been found in ovarian cancers, ample evidence also suggests an important role of epigenetic changes in the disease occurrence and progression. Because epigenetic changes do not alter DNA sequence and can be reversed or reprogrammed, they offer an attractive avenue for therapeutic intervention in cancer treatment. Using quantitative RT-PCR assays, we systematically examined the expression of 7 H1 genes in 33 human epithelial ovarian tumors. By clustering analysis, we found that ovarian malignant adenocarcinomas and benign adenomas exhibited characteristic expression patterns. We demonstrate that expression profiling of 7 H1 genes in tumor samples discriminates adenocarcinomas vs. adenomas with high accuracy. These findings indicate that the expression of H1 variants is exquisitely regulated and may serve as potential epigenetic biomarkers for ovarian cancer. To further investigate the role of H1 subtypes in ovarian cancer cells, we employ an over-expression approach to test the function of H1 subtypes in an ovarian cancer cell line OVCAR-3. We found that histone H1.3 over-expression significantly suppresses the growth and colony formation of OVCAR-3 cells. Gene expression arrays identified many genes affected by H1.3 over-expression, and oncogene H19 is among the genes most dramatically repressed by H1.3 over-expression. Over-expression of several other H1 subtypes does not lead to significant reduction of H19 expression, suggesting a specific effect by H1.3. Consistently, knockdown of H1.3 increases H19 expression. Furthermore, increased expression of H1.3 leads to accumulation of H1.3 as well as increased DNA methylation at the regulatory regions of H19. Finally we identified a synergistic effect of H1.3 over-expression and H19 knockdown on inhibition of ovarian cancer cell growth. These results establish oncogene H19 as a direct target of histone H1.3, identify a novel role of H1 variants in ovarian cancer mediated through regulating oncogene H19 expression, and may offer new approaches for ovarian cancer therapeutics.

No description available.

Zugl.: Giessen, University, Diss., 2008.

Zugl.: Giessen, University, Diss., 2008.

Cycloalkyl analogues of Antergan with the basic structure of N, N-dimethyl-N’-cycloalkylmethyl-N’-phenylethylenedi-amlne have been synthesized in good yields. The alkyl group was a butyl-, pentyl-, hexyl-, or heptyl-ring structure. The compounds with the benzyl group of Antergan substituted by a hydrogen or a methyl group were also synthesized in good yields. The general reaction sequence followed was to start with the appropriate cycloalkanecarboxyllc acid and build up to a secondary amine via an acid chloride and an amide. Leung’s methods (1) were followed and checked up to this step. Further reaction sequences were developed during this study. The desired amine was reacted with chloroacetyl chloride, dimethylamine and then reduced to the tertiary diamine analogues. The preliminary antihistamine activity of these analogues was studied and compared with that of Diphenhydramine Hydrochloride Standard Solution. The relative activity of each analogue was also determined. / Pharmaceutical Sciences, Faculty of / Graduate

Methyl-CpG binding protein 2 (MeCP2) and histone H1 are important chromatin associated proteins. Both exhibit their own extent of complexity as MeCP2 is an intrinsically disordered protein (IDP) that interacts with many different partners involved in several cellular processes and histone H1 consists of 11 different subtypes each of them associated with different posttranslational modifications (PTMs). An interesting avenue for the study of these proteins is in neurons where MeCP2 is very abundant and histone H1 level is half that observed in other somatic tissues. Several reports in the past have proposed that this lower level of histone H1 is due to the abundance of MeCP2 which displaces histone H1. However, this hypothesis has been debated and there is no clear consensus. In an attempt to study this controversy, a cell model system ReNCell WT and MeCP2-KO was used that can be induced to differentiate into neurons. The protein levels, transcript levels and localization of histone H1 subtypes in these cells were analyzed using HPLC, RT-qPCR and immunofluorescence, respectively. The results show that ReNCell WT and MeCP2-KO do not exhibit significant differences in their relative amount of histone H1 protein and transcript level neither at the proliferative nor at the later differentiated stages. However, HPLC analyses show that the histone H1 subtypes of these two cell types exhibit significant elution differences probably resulting from differences in their PTM content. Immunofluorescence analyses show that WT ReNCell differentiation as determined by extension of dendritic or axonic processes can be seen to occur over the course of one week and there is a significant difference in the nuclear area of these two cells at 8 DIV. This study provides important preliminary data for future research in MeCP2 and histone H1 using this cell model system and show that MeCP2 may have a bearing on histone H1 PTMs. / Graduate

Das Internet versetzt Unternehmen in die Lage auf Kundenanfragen und-beschwerden schnell und individuell zu reagieren. Es schafft die technische Vorraussetzung für eine wechselseitige Kommunikation zwischen dem Unternehmen und dem (potentiellen) Kunden. Der direkte Dialog über das Internet bietet dem Kunden die Möglichkeit, jederzeit mit Beschwerden, Anfragen oder Reklamationen an das Unternehmen heranzutreten. Voraussetzung für eine gelungene Kunden-Kommunikation via Internet ist jedoch ein gut funktionierendes E-Mail-Management der Unternehmen.

Les débats sur l’état des rapports entre le champ économique, politique et scientifique vont bon train depuis quelques années. Dans ce mémoire, nous nous sommes efforcés de conceptualiser ces rapports à l’aide de la théorie du champ scientifique en prenant comme objet le Programme des Actions Concertées (PAC), un programme de subvention de recherche thématique qui existe dans les trois fonds subventionnaires du Québec, mais financé principalement par le Fonds québécois de recherche sur la nature et les technologies (FQRNT) conjointement avec des organisations gouvernementales et des entreprises privées. Plus précisément, nous nous sommes demandé quelle est la position du PAC au sein des rapports entre le champ politique, économique et scientifique et quelles sont les propriétés que possèdent en commun les chercheurs qui transitent par ce programme.Ce questionnement supposait que nous puissions d’abord décrire la genèse, le développement et le fonctionnement du PAC, en un mot, son histoire, ce qui n’a encore jamais été fait pour ce programme ni même pour le FQRNT. Grâce à la consultation des documents administratifs du Fonds et à diverses autres sources primaires et secondaires, nous avons été en mesure de produire une telle description et montrer comment, lors de sa création dans les années 1970, le programme a profité de l’investissement initial de chercheurs très actifs dans le milieu industriel puis comment, dans les années 1980, il a profité des politiques économiques interventionnistes du gouvernement québécois. D’autre part, en utilisant le Système d’information sur la recherche universitaire (SIRU) et les réponses des chercheurs financés obtenues lors d’une enquête par questionnaire, nous avons été en mesure de reconstituer le profil d’un échantillon de chercheurs soumissionnaires.En regard des résultats que nous avons obtenus, nous émettons l’hypothèse selon laquelle le PAC est un programme à qui ses concepteurs ont donné une configuration qui favorise la reconnaissance d’une forme de capital qui n’est pas spontanément reconnue par les pairs. Ce capital s’acquiert entre autres lors de recherches antérieures réalisées pour le compte des « intervenants du milieu », notamment les partenaires financiers du Fonds. De la même façon que le capital scientifique obtient son rendement maximal lors de l’évaluation scientifique par les pairs, c’est lors de l’évaluation des demandes de financement par un comité composé des partenaires financiers du Fonds que le capital de « pertinence » offre le plus haut rendement. Ainsi, les chercheurs qui ont déjà réalisé des recherches pour les intervenants du milieu concerné ont, devant ce comité, des chances de succès 1,4 fois supérieures aux autres chercheurs, et nous faisons l’hypothèse que le capital que nous avons mis en évidence se compose pour une part d’un capital culturel spécifique (possédé sous la forme d’une connaissance pragmatique des problèmes propres au milieu concerné par l’Action concertée et des codes en usage pour les énoncer) et d’un capital social spécifique (possédé sous la forme d’un réseau d’alliés dans le milieu en question et notamment parmi les partenaires financiers du Fonds). / FQRNT / CIRST

Cassava (Manihot esculenta Crantz) is an important tropical crop which provides a large portion of daily calories intake to hundreds of millions of people in Africa, Latin America, and tropical Asia. Cassava is grown for its starchy storage roots as staple food, as animal feed, and as industrial raw material. The utilisation of cassava is hindered by its characteristic physiological response, the post-harvest physiological deterioration (PPD). The inevitable wounding caused during harvesting and handling will trigger a series of physiological responses within 24 to 48 hours, which causes a blue-black discoloration in the storage roots, rendering these roots unmarketable and unpalatable in a few days. During the PPD response large amount of phenylpropanoid compounds, especially scopoletin and its glycoside, accumulate in the roots. Scopoletin may play an important role in PPD development but little work has been done on the possible relationship. Here we aim to examine the effects of altering scopoletin synthesis in cassava roots on the PPD response. In Arabidopsis thaliana, gene F6’H1 (feruloul CoA 6’-hydroxylase 1) is indispensable in the biosynthesis of scopoletin. Cassava F6’H1 candidate gene family involved in scopoletin synthesis were identified by their ability to functionally complement F6’H1 T-DNA insertion mutation in Arabidopsis thaliana that prevented synthesis of scopoletin. RNAi constructs targeting the identified cassava F6’H1 candidate gene family were designed, under the control of either constitutive CaMV 35S or root-specific StPAT promoters. These were used to transform wild-type cassava to down-regulate the expression of these scopoletin synthetic genes in F6’H1 gene family. The inhibition of cassava F6’H1 candidate gene expression and thus the scopoletin synthesis in transgenic cassava roots were confirmed by qRT-PCR and LC-MS, respectively. The RNAi transgenic cassava lines show less scopoletin accumulation and inhibited F6’H1 candidate genes expression during the PPD response. A reduced PPD discoloration development compared to that of the wild-type was also observed in the RNAi transgenic cassava lines.

Throughout the last glacial period, massive volumes of icebergs were discharged periodically from the Hudson Strait region during so-called Heinrich (H) events depositing sediments in distinct layers across the North Atlantic as they melted. The objective of this research was to measure and describe sedimentation associated with a meltwater plume discharged during the H1 ice-rafting event (14–19 ka) by examining sediment texture. The H1 layer was sampled in 11 piston cores that cover about 4000 km of the slope between Hudson Strait and the Bay of Fundy and range in water depth from 818–2740 m. Disaggregated inorganic grain size (DIGS) distributions were determined using a Coulter Counter. Additionally, carbonate content and the coarse fraction were measured and DIGS spectra were parameterized using an inverse ?oc model and sorted using entropy analysis. Results suggest that H1 layer sediments were mainly delivered by plume, ice-rafting and turbidity currents. In general, plume deposition was only significant proximally and distal sediments were mainly delivered by ice-rafting. However, the lack of plume deposited sediments distally does not necessarily imply the absence of a plume.