• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 3817
  • 1114
  • 864
  • 736
  • 517
  • 250
  • 200
  • 132
  • 74
  • 71
  • 63
  • 58
  • 58
  • 58
  • 58
  • Tagged with
  • 9639
  • 1342
  • 902
  • 851
  • 751
  • 734
  • 718
  • 607
  • 577
  • 574
  • 573
  • 551
  • 537
  • 467
  • 435
  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.

Group I aptazymes as genetic regulatory switches

Marshall, Kristin Ann. January 2001 (has links)
Thesis (Ph. D.)--University of Texas at Austin, 2001. / Vita. Includes bibliographical references. Available also from UMI/Dissertation Abstracts International.

US-amerikanische und deutsche Wettbewerbspolitik gegenüber Marktmacht eine vergleichende Untersuchung und kritische Analyse der Rechtsprechung gegenüber Tatbeständen des externen und internen Unternehmerwachstums sowie des Behinderungswettbewerbs.

Schmidt, Ingo. January 1900 (has links)
Habilitationsschrift--Ruhr-Universität Bochum. / Bibliography: p. [457]-475.

Identification of novel regulatory mechanisms controlling heterocyst development in Anabaena Sp. strain PCC 7120

Aldea, Maria Ramona 15 May 2009 (has links)
The regulatory mechanisms that govern heterocyst development in Anabaena sp. strain PCC 7120 have been continuously refined over the last two decades. In this work, we show that three of the sigma factor genes present in the Anabaena sp. strain PCC 7120 genome are developmentally regulated. Time-lapse microscopy of gfp reporter strains indicated that expression of sigC, sigG, and sigE is upregulated specifically in differentiating cells at 4 h, 9 h and 16 h, respectively, after induction of heterocyst development. We proposed that the sigma factors encoded by these genes are involved in regulation of heterocyst-specific genes whose expression is relatively coincident with that of sigC, sigG, or sigE. Indeed, inactivation of the sigC gene caused delayed and reduced expression of genes required for the early stages of heterocyst development, and caused delayed development. Inactivation of the sigE gene caused a considerable drop in expression of nifH, a late gene required for nitrogen fixation. We also provide evidence that c-di-GMP, a novel bacterial second messenger, is involved in regulating heterocyst development. The all2874 gene encodes a bona fide diguanylate cyclase, which synthesizes c-di-GMP, and the gene's inactivation resulted in a decreased tendency to form heterocysts; this phenotype was exacerbated by high light intensity. We hypothesize that the putative operon all2875-all2874 senses and relays information about light conditions and this information is integrated into the decision to form heterocysts. Finally, we identified the all0187 gene, which is expressed at 9 h, a time when cells that have initiated differentiation commit to complete the process. In nitrogen-free medium, all0187 mutant filaments formed abnormally long heterocysts and were unable to grow diazotrophically. Septum formation between heterocysts and their flanking vegetative cells was incomplete, leaving one or both poles of the heterocysts more opened and potentially more permeable to oxygen. Despite having nitrogenase activity, the all0187 mutant was unable to grow diazotrophically. We hypothesize that the diazotrophic growth defect is caused by the inability of the heterocysts to transport fixed nitrogen to the neighboring vegetative cells.

Regulation of the Gene Encoding Thrombin-Activable Fibrinolysis Inhibitor

Garand, MATHIEU 12 April 2010 (has links)
Disequilibrium between coagulation and fibrinolysis can lead to severe haemostatic disorders such as thrombosis and hemophilia. Thrombin-activable fibrinolysis inhibitor (TAFI) is a carboxypeptidase B-like pro-enzyme that, once activated, attenuates fibrinolysis. TAFI may also mediate connections between coagulation and inflammation. Studies have associated high plasma TAFI levels with risk for thrombotic diseases. Interestingly, steroid hormones, such as estrogen and progestogens used in hormone replacement therapy or oral contraceptive preparations, have been shown to affect plasma TAFI levels. Regulation of the expression of the gene encoding TAFI, CBP2, is likely an important determinant of the role of the TAFI pathway in vivo; this concept motivated the investigations described in this thesis. In Chapter 2, the results of my research lead to the identification of key transcription factors regulating CPB2. Specifically, we described the binding of NF-Y and HNF-1 to the CPB2 promoter. NF-Y was shown to be an important factor for the basal CPB2 promoter activity. Binding of HNF-1 is essential for the activity of the promoter and is potentially responsible for the liver specific expression of CPB2. In Chapter 3, we set to investigate the effect of female sex hormone on hepatic expression of CPB2. We demonstrated that the levels of TAFI protein secreted from cultured hepatoma cells (HepG2) are decreased by 17beta-estradiol and progesterone. The change in protein expression was paralleled by decreases in CPB2 mRNA abundance and promoter activity. Deletion analysis of the CPB2 promoter indicated that the genomic effects of estrogen and progesterone are likely mediated via a non-classical mechanism. In Chapter 4, we evaluated the effects of various inflammatory mediators on expression of the gene encoding mouse TAFI (Cpb2). Our results showed that Cpb2 mRNA abundance and promoter activity are up-regulated by inflammatory mediators IL-1beta, IL-6, and TNFalpha. We also showed that TNFalpha mediates its effect via the binding of NFkB. Additionally, our results suggest that TNFalpha promotes the binding of NFkB to the promoter by increasing its translocation to the nucleus. The NFkB site is not conserved between human and mouse and may explained the different responses to inflammation observed in vivo. / Thesis (Ph.D, Biochemistry) -- Queen's University, 2009-09-25 16:56:46.043

Germinal centre cell proliferation in murine spleens

Goodlad, J. R. January 1994 (has links)
Germinal centres are dynamic structures in which a number of kinetic processes take place. This thesis was designed to investigate mechanisms whereby one of these kinetic events, germinal centre cell proliferation, is regulated <I>in vivo</I>. In order to achieve this, the proliferative rate of germinal centre cells was measured in C3H/HeN mice under a variety of experimental conditions. In particular, the effect on germinal centre cell proliferation of different classes of antigen and of variously timed doses of the immunosuppressant drug cyclosporin A, was examined. In some experiments, an immunohistochemical technique was employed to demonstrate the distribution of antigen within murine spleens and to correlate the presence of antigen within germinal centres with the germinal centre cell birth rate. The results showed that the type of antigen to which an animal is exposed does determine the subsequent rate of germinal centre cell proliferation. In addition it became apparent that specific regulatory mechanisms were at work within murine germinal centres which either stimulated or inhibited germinal centre cell proliferation depending on the stage of the germinal centre reaction. The proliferative response to antigen was also significantly affected by treatment of the animals with cyclosporin A. The effect of the drug varied depending on the timing of its administration in relation to antigen. These results indicated that T cell derived cytokines play a central role in regulating both stimulation and inhibition of germinal centre cell proliferation. It is proposed that interleukin-4 and interleukin-5 are involved in driving the former, while interferon-γ is a candidate for mediating the latter.

Characterisation of the intestinal basolateral peptide transporter

Henderson, Fiona D. January 2003 (has links)
No description available.

Creatine content and uptake in muscle

Willott, Claire Amanda January 1998 (has links)
No description available.

Sources of variability in pre-Bötzinger complex rhythmic patterns generated by a transverse slice : a simulation study

Gerken, William C. 08 1900 (has links)
No description available.

Transcriptional Regulation of the Type 1 Interferon Response by a Nuclear Pore Protein.

Aintablian, Haig 28 March 2018 (has links)
A Thesis submitted to The University of Arizona College of Medicine - Phoenix in partial fulfillment of the requirements for the Degree of Doctor of Medicine.

Establishing the Relevant Standards of Human Rights Protection under Dublin Regulation - A question of more than responsibility determination?

Sofy, Laura January 2016 (has links)
No description available.

Page generated in 0.1361 seconds