579 resultados para Founder
Resumo:
Transgenic mouse lines have been developed that express the tv-a receptor under the control of the chicken beta-actin promoter. These mice express the tv-a receptor in most or all tissues and in the early embryo. An avian leukosis virus (ALV)-based retroviral vector system was used for the efficient delivery of genes into preimplantation mouse embryos from these transgenic lines. Experimental animals could be generated quickly and easily by infecting susceptible blastocysts with ALV-based retroviral vectors. Expression of the delivered genes was controlled by either the constitutive viral promoter contained in the long terminal repeat or an internal nonviral tissue-specific promoter. Mating the infected founder chimeric animals produced animals that carry the ALV provirus as a transgene. A subset of the integrated proviruses expressed the chloramphenicol acetyltransferase reporter gene from either the promoter in the long terminal repeat or an internal promoter, which we believe indicates that many of the sites that are accessible to viral DNA insertion in preimplantation embryos are incompatible with expression in older animals. This approach should prove useful for studies on murine cell lineage and development, providing models for studying oncogenesis, and testing gene therapy strategies.
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Most evolutionary studies of oceanic islands have focused on the Pacific Ocean. There are very few examples from the Atlantic archipelagos, especially Macaronesia, despite their unusual combination of features, including a close proximity to the continent, a broad range of geological ages, and a biota linked to a source area that existed in the Mediterranean basin before the late Tertiary. A chloroplast DNA (cpDNA) restriction site analysis of Argyranthemum (Asteraceae: Anthemideae), the largest endemic genus of plants of any volcanic archipelago in the Atlantic Ocean, was performed to examine patterns of plant evolution in Macaronesia. cpDNA data indicated that Argyranthemum is a monophyletic group that has speciated recently. The cpDNA tree showed a weak correlation with the current sectional classification and insular distribution. Two major cpDNA lineages were identified. One was restricted to northern archipelagos--e.g., Madeira, Desertas, and Selvagens--and the second comprised taxa endemic to the southern archipelago--e.g., the Canary Islands. The two major radiations identified in the Canaries are correlated with distinct ecological habitats; one is restricted to ecological zones under the influence of the northeastern trade winds and the other to regions that are not affected by these winds. The patterns of phylogenetic relationships in Argyranthemum indicate that interisland colonization between similar ecological zones is the main mechanism for establishing founder populations. This phenomenon, combined with rapid radiation into distinct ecological zones and interspecific hybridization, is the primary explanation for species diversification.
Resumo:
The 5' region of the human lysozyme gene from -3500 to +25 was fused to a chloramphenicol acetyltransferase (CAT) reporter gene and three transgenic founder mice were obtained. All three transgenic lines showed the same pattern of CAT enzyme expression in adult mouse tissues that was consistent with the targeting of elicited, activated macrophages in tissues and developing and elicited granulocytes. In normal mice high CAT enzyme activity was found in the spleen, lung, and thymus, tissues rich in phagocytically active cells, but not in many other tissues, such as the gut and muscle, which contain resident macrophages. Cultured resident peritoneal macrophages and cells elicited 18 hr (granulocytes) and 4 days (macrophages) after injection of sterile thioglycollate broth expressed CAT activity. Bacillus Calmette-Guérin infection of transgenic mice resulted in CAT enzyme expression in the liver, which contained macrophage-rich granulomas, whereas the liver of uninfected mice did not have any detectable CAT enzyme activity. Although the Paneth cells of the small intestine in both human and mouse produce lysozyme, the CAT gene, under the control of the human lysozyme promoter, was not expressed in the mouse small intestine. These results indicate that the human lysozyme promoter region may be used to direct expression of genes to activated mouse myeloid cells.
Resumo:
Transgenic mice carrying heterologous genes directed by a 670-bp segment of the regulatory sequence from the human transferrin (TF) gene demonstrated high expression in brain. Mice carrying the chimeric 0.67kbTF-CAT gene expressed TF-CAT in neurons and glial cells of the nucleus basalis, the cerebrum, corpus callosum, cerebellum, and hippocampus. In brains from two independent TF-CAT transgenic founder lines, copy number of TF-CAT mRNA exceeded the number of mRNA transcripts encoding either mouse endogenous transferrin or mouse endogenous amyloid precursor protein. In two transgenic founder lines, the chloramphenicol acetyltransferase (CAT) protein synthesized from the TF-CAT mRNA was estimated to be 0.10-0.15% of the total soluble proteins of the brain. High expression observed in brain indicates that the 0.67kbTF promoter is a promising director of brain expression of heterologous genes. Therefore, the promoter has been used to express the three common human apolipoprotein E (apoE) alleles in transgenic mouse brains. The apoE alleles have been implicated in the expression of Alzheimer disease, and the human apoE isoforms are reported to interact with different affinities to the brain beta-amyloid and tau protein in vitro. Results of this study demonstrate high expression and production of human apoE proteins in transgenic mouse brains. The model may be used to characterize the interaction of human apoE isoforms with other brain proteins and provide information helpful in designing therapeutic strategies for Alzheimer disease.
Resumo:
The ZNF91 gene family, a subset of the Krüppel-associated box (KRAB)-containing group of zinc finger genes, comprises more than 40 loci; most reside on human chromosome 19p12-p13.1. We have examined the emergence and evolutionary conservation of the ZNF91 family. ZNF91 family members were detected in all species of great apes, gibbons, Old World monkeys, and New World monkeys examined but were not found in prosimians or rodents. In each species containing the ZNF91 family, the genes were clustered at one major site, on the chromosome(s) syntenic to human chromosome 19. To identify a putative "founder" gene, > 20 murine KRAB-containing zinc finger protein (ZFP) cDNAs were randomly cloned, but none showed sequence similarity to the ZNF91 genes. These observations suggest that the ZNF91 gene cluster is a derived character specific to Anthropoidea, resulting from a duplication and amplification event some 55 million years ago in the common ancestor of simians. Although the ZNF91 gene cluster is present in all simian species, the sequences of the human ZNF91 gene that confer DNA-binding specificity were conserved only in great apes, suggesting that there is not a high selective pressure to maintain the DNA targets of these proteins during evolution.
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We have generated transgenic mice bearing the diphtheria toxin A chain (DTA) gene under the control of granzyme A (GrA) promoter sequences (GrA-DTA). GrA is expressed in activated cytotoxic cells but not in their immediate progenitors. These GrA-DTA mice are deficient in cytotoxic functions, indicating that most cytotoxic cells express GrA in vivo. Surprisingly, one founder strain containing a multicopy GrA-DTA insert show a marked and selective deficiency in CD8+ cells in peripheral lymphoid organs. This depletion was not observed in thymus, where the distribution of CD4+ and CD8+ cells is normal. Moreover, the emigration of T cells from thymus is normal, indicating that the depletion occurs in the periphery. GrA-DTA mice should be useful as models to dissect the role of cytotoxic cells in immune responses and as recipients of normal and neoplastic hematopoietic cells. The selective depletion of CD8+ cells in one founder strain could have implications for postthymic T-cell development.
Resumo:
In the sea urchin embryo, the lineage founder cells whose polyclonal progenies will give rise to five different territories are segregated at the sixth division. To investigate the mechanisms by which the fates of embryonic cells are first established, we looked for temporal and spatial expression of homeobox genes in the very early cleavage embryos. We report evidence that PlHbox12, a paired homeobox-containing gene, is expressed in the embryo from the 4-cell stage. The abundance of the transcripts reaches its maximum when the embryo has been divided into the five polyclonal territories--namely at the 64-cell stage--and it abruptly declines at later stages of development. Blastomere dissociation experiments indicate that maximal expression of PlHbox12 is dependent on intercellular interactions, thus suggesting that signal transduction mechanisms are responsible for its transcriptional activation in the early cleavage embryo. Spatial expression of PlHbox12 was determined by whole-mount in situ hybridization. PlHbox12 transcripts in embryos at the fourth, fifth, and sixth divisions seem to be restricted to the conditionally specified ectodermal lineages. These results suggest a possible role of the PlHbox12 gene in the early events of cell specification of the presumptive ectodermal territories.
Resumo:
A technique is described that greatly increases the efficiency of recovering specific locus point mutations in zebrafish (Danio rerio). Founder individuals that were mosaic for point mutations were produced by mutagenizing postmeiotic gametes with the alkylating agent N-ethyl-N-nitrosourea. Under optimal conditions, each founder carried an average of 10 mutations affecting genes required for embryogenesis. Moreover, approximately 2% of these founders transmitted new mutations at any prespecified pigmentation locus. Analyses of new pigmentation mutations confirmed that most were likely to be point mutations. Thus, mutagenesis of postmeiotic gametes with N-ethyl-N-nitrosourea yielded frequencies of point mutations at specific loci that were 10- to 15-fold higher than previously achieved in zebrafish. Our procedure should, therefore, greatly facilitate recovery of multiple mutant alleles at any locus of interest.
Resumo:
This research aims to show the main points of convergence between hegemonic schools of economic and sociological theory from the Scottish Enlightenment until today. To this end, on the one hand, we set three basic families of economic thought (the mainstream, the Austrian school and Marxism); and, on the other, we divide the history of sociology in five major generations (pioneers, founders, institutionalizers, compilers and constructivist). Subsequently, we set five historical periods as reference to our respective chapters and compare, within each of them, the theoretical contributions from these two areas. Thus, in the first chapter, called "the liberal parenthesis", we consider the relationship between the classical school of economics and the pioneers and founders of sociology. In the second, entitled "the social question" we analyze, on the one hand, the theoretical consistency of both the neoclassical school, as Austrian, with the principles defended by the institutionalizers of sociology; and, on the other, the influence of Karl Marx, as founder of sociology and classical economist, in the work of Soviet revolutionary theorists. In chapter three, called the "new industrial state", we demonstrate the theoretical proximity between both Keynesianism and the Austrian school of economics, with the doctrine defended by the generation of compilers in sociology. The fourth chapter, entitled "second industrial divide", refers to the similarities between the theoretical contributions of the monetarist Chicago school and the Austrian school with sociological constructivism. Finally, chapter five, the "global market", shows that the two hegemonic schools in economics, "integrated model", and sociology, "analytical sociology", are composed of the same three schools of thought: the rational choice, the neo-institutionalism and network approach. Thus, we can conclude that, if we look at their respective areas of influence, during this historical period occurs an manifest agreement between the theoretical contributions from the economic and sociological fields.
Resumo:
¿Qué forma final tenía el proyecto de la Modernidad, iniciado en el siglo XVIII? No es relevante. Aquí se desgrana la trayectoria de mujeres que desde sus profesiones influyeron decisivamente en la arquitectura. Se constata que estas aportaciones se realizaron desde países con Democracia donde se favorecía la libertad individual, la educación y la independencia económica; es decir: donde la responsabilidad se depositaba en función de la capacitación. Tres ámbitos de estudio: la higiene, la vivienda y la ciudad a lo largo de los siglos XIX y XX. La primera protagonista es la fundadora de la Enfermería que sienta los principios de la higiene a partir de la experiencia traducida a cifras. La segunda es una serie de diseñadoras y editoras que se interesaron por los nuevos modos de vivir que se ensayaron en USA a mitad de siglo XX, apostando por las imágenes. La tercera es una periodista que reflexionó en torno al urbanismo que se estaba dando en dicho periodo, sintetizando su pensamiento en un libro. Una reflexión entorno al poder de las cifras, las imágenes y las palabras.
Resumo:
Two letters, signed John B. Sartori, the founder of the first spaghetti factory in the United States, regarding the production and sales of pasta.
Resumo:
Daniel Bates wrote these five letters to his friend and classmate, William Jenks, between May 1795 and September 1798. In a letter written May 12, 1795, Bates informs Jenks, who was then employed as an usher at Mr. Webb's school, of his studies of Euclid, the meeting of several undergraduate societies, and various sightings of birds, gardens and trees. In a letter written in November 1795 from Princeton, where he was apparently on vacation with the family of classmate Leonard Jarvis, he describes playing the game "break the Pope's neck" and tells Jenks what he was reading (Nicholson, Paley?, and Thompson) and what his friend's father was reading (Mirabeau and Neckar).
Resumo:
John Hubbard Church wrote these twelve letters to his friend and classmate William Jenks between 1795 and 1798. Church wrote the letters from Boston, Rutland, Cambridge, and Chatham in Massachusetts and from Somers, Connecticut; they were sent to Jenks in Cambridge and Boston, where for a time he worked as an usher in Mr. Vinall's school and Mr. Webb's school. Church's letters touch on various subjects, ranging from his increased interest in theology and his theological studies under Charles Backus to his seasickness during a sailing voyage to Cape Cod. Church also informs Jenks of what he is reading, including works by John Locke, P. Brydone, James Beattie, John Gillies, Plutarch, and Alexander Pope. He describes his work teaching that children of the Sears family in Chatham, Massachusetts, where he appears to have spent a significant amount of time between 1795 and 1797. Church's letters are at times very personal, and he often expresses great affection for Jenks and their friendship.
Resumo:
These two handwritten letters by Timothy Pickering were written on February 14, 1797 and June 14, 1798 to his brother John Pickering and his father Timothy Pickering, respectively. The letter to his brother, John, discusses mutual friends, classmate Thomas Lee, and John’s recent attendance at a sermon by Dr. Joseph Priestley. The letter from Timothy to his father includes a discussion of Timothy’s expenses and the amount of money needed to pay his debts, a request for new shoes for commencement, the news of Timothy’s invitation to join honor society Phi Beta Kappa, and a few comments on his forensics course at Harvard.
Resumo:
Following several years of political turmoil triggered by constitutional reform (a shift from a presidential to a semi-presidential system) and electoral reshuffles (parliamentary elections in 2012; presidential elections in 2013), the political situation in Georgia has stabilised: key posts in the country are now in the hands of democratically elected members of the Geor-gian Dream coalition. Despite its mosaic-like structure and internaltensions, Georgian Dream remains strong and enjoys high levels of public support. This puts it in good stead to play a central role in Georgian politics in the foreseeable future, including securing victory in the local government elections scheduled for June. However, local billionaire Bidzina Ivanishvili does not currently hold a political office - despite the fact that he is the founder, sponsor and undisputed leader of the coalition, as well as former prime minister and the most popular public figure in Georgia (besides Patriarch Ilia II). This raises several questions, for example: Who is really at the helm of the Georgian state? What is the lon-g-term vision of the current government? The past achievements of the politically heterogeneo-us Georgian Dream - dominated by Mr Ivanishvili - offer little help in answering these questions. In addition to a series of challenges on the domestic front, the new Georgian leadership is also facing strategic geopolitical challenges, compounded by the current conflict in Ukraine. These include the future of Georgia’s relations with the West (including the process of EU and NATO integration) and with Russia (in response to repeated attempts to re-integrate the post-Soviet republics). The scale and dynamism of the changes in both the geopolitical order in the post-Soviet region and in the relations between Russia and the West are causing further questions to be raised about their impact on the position of the Georgian political elite and about their consequences for the entire country.