482 resultados para Pratt


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Barley (Hordeum vulgare L.) is a long-day plant whose flowering is enhanced when the photoperiod is supplemented with far-red light, and this promotion is mediated by phytochrome. A chemically mutagenized dwarf cultivar of barley was selected for early flowering time (barley maturity daylength response [BMDR]-1) and was made isogenic with the cultivar Shabet (BMDR-8) by backcrossing. BMDR-1 was found to contain higher levels of both phytochrome A and phytochrome B in the dark on immunoblots with monoclonal antibodies from oat (Avena sativa L.) that are specific to different members of the phytochrome gene family. Phytochrome A was light labile in both BMDR-1 and BMDR-8, decreasing to very low levels after 4 d of growth in the light. Phytochrome B was light stable in BMDR-8, being equal in both light and darkness. However, phytochrome B became light labile in BMDR-1 and this destabilization of phytochrome B appeared to make BMDR-1 insensitive to photoperiod. In addition, both the mutant and the wild type lacked any significant promotion of flowering in response to a pulse of far-red light given at the end of day, and the end-of-day, far-red inhibition of tillering is normal in both, suggesting that phytochrome B is not involved with these responses in barley.

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In animal cell lysates the multiprotein heat-shock protein 90 (hsp90)-based chaperone complexes consist of hsp70, hsp40, and p60. These complexes act to convert steroid hormone receptors to their steroid-binding state by assembling them into heterocomplexes with hsp90, p23, and one of several immunophilins. Wheat germ lysate also contains a hsp90-based chaperone system that can assemble the glucocorticoid receptor into a functional heterocomplex with hsp90. However, only two components of the heterocomplex-assembly system, hsp90 and hsp70, have thus far been identified. Recently, purified mammalian p23 preadsorbed with JJ3 antibody-protein A-Sepharose pellets was used to isolate a mammalian p23-wheat hsp90 heterocomplex from wheat germ lysate (J.K. Owens-Grillo, L.F. Stancato, K. Hoffmann, W.B. Pratt, and P. Krishna [1996] Biochemistry 35: 15249â15255). This heterocomplex was found to contain an immunophilin(s) of the FK506-binding class, as judged by binding of the radiolabeled immunosuppressant drug [3H]FK506 to the immune pellets in a specific manner. In the present study we identified the immunophilin components of this heterocomplex as FKBP73 and FKBP77, the two recently described high-molecular-weight FKBPs of wheat. In addition, we present evidence that the two FKBPs bind hsp90 via tetratricopeptide repeat domains. Our results demonstrate that binding of immunophilins to hsp90 via tetratricopeptide repeat domains is a conserved protein interaction in plants. Conservation of this protein-to-protein interaction in both plant and animal cells suggests that it is important for the biological action of the high-molecular-weight immunophilins.

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A molecular model of poorly understood hydrophobic effects is heuristically developed using the methods of information theory. Because primitive hydrophobic effects can be tied to the probability of observing a molecular-sized cavity in the solvent, the probability distribution of the number of solvent centers in a cavity volume is modeled on the basis of the two moments available from the density and radial distribution of oxygen atoms in liquid water. The modeled distribution then yields the probability that no solvent centers are found in the cavity volume. This model is shown to account quantitatively for the central hydrophobic phenomena of cavity formation and association of inert gas solutes. The connection of information theory to statistical thermodynamics provides a basis for clarification of hydrophobic effects. The simplicity and flexibility of the approach suggest that it should permit applications to conformational equilibria of nonpolar solutes and hydrophobic residues in biopolymers.

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In Escherichia coli, the sigma factor, RpoS, is a central regulator in stationary-phase cells. We have identified a gene, sprE (stationary-phase regulator), as essential for the negative regulation of rpoS expression. SprE negatively regulates the rpoS gene product at the level of protein stability, perhaps in response to nutrient availability. The ability of SprE to destabilize RpoS is dependent on the ClpX/ClpP protease. Based on homology, SprE is a member of the response regulator family of proteins. SprE is the first response regulator identified that is implicated in the control of protein stability. Moreover, SprE is the first reported protein that appears to regulate rpoS in response to a specific environmental parameter.

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The type 1 angiotensin II (AT1) receptor is well characterized but the type 2 (AT2) receptor remains an enigma. We tested the hypothesis that the AT2 receptor can modulate the growth of vascular smooth muscle cells by transfecting an AT2 receptor expression vector into the balloon-injured rat carotid artery and observed that overexpression of the AT2 receptor attenuated neointimal formation. In cultured smooth muscle cells, AT2 receptor transfection reduced proliferation and inhibited mitogen-activated protein kinase activity. Furthermore, we demonstrated that the AT2 receptor mediated the developmentally regulated decrease in aortic DNA synthesis at the latter stages of gestation. These results suggest that the AT2 receptor exerts an antiproliferative effect, counteracting the growth action of AT1 receptor.

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Vertebrate hematopoietic stem cells are derived from vental mesoderm, which is postulated to migrate to both extra- and intraembryonic positions during gastrula and neurula stages. Extraembryonic migration has previously been documented, but the origin and migration of intraembryonic hematopoietic cells have not been visualized. The zebrafish and most other teleosts do not form yolk sac blood islands during early embryogenesis, but instead hematopoiesis occurs solely in a dorsal location known as the intermediate cell mass (IM) or Oellacher. In this report, we have isolated cDNAs encoding zebrafish homologs of the hematopoietic transcription factors GATA-1 and GATA-2 and have used these markers to determine that the IM is formed from mesodermal cells in a posterior-lateral position on the yolk syncytial layer of the gastrula yolk sac. Surprisingly, cells of the IM then migrate anteriorly through most of the body length prior to the onset of active circulation and exit onto the yolk sac. These findings support a hypothesis in which the hematopoietic program of vertebrates is established by variations in homologous migration pathways of extra- and intraembryonic progenitors.

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To elucidate the functions of human immunodeficiency virus type 1 (HIV-1) genes in a nonhuman primate model, we have constructed infectious recombinant viruses (chimeras) between the pathogenic molecular clone of simian immunodeficiency virus (SIV) SIVmac239 and molecular clones of HIV-1 that differ in phenotypic properties controlled by the env gene. HIV-1SF33 is a T-cell-line-tropic virus which induces syncytia, and HIV-1SF162 is a macrophage-tropic virus that does not induce syncytia. A DNA fragment encoding tat, rev, and env (gp160) of SIVmac239 has been replaced with the counterpart genetic region of HIV-1SF33 and HIV-1SF162 to derive chimeric recombinant simian/human immunodeficiency virus (SHIV) strains SHIVSF33 and SHIVSF162, respectively. In the acute infection stage, macaques inoculated with SHIVSF33 had levels of viremia similar to macaques infected with SIVmac239, whereas virus loads were 1/10th to 1/100th those in macaques infected with SHIVSF162. Of note is the relatively small amount of virus detected in lymph nodes of SHIVSF162-infected macaques. In the chronic infection stage, macaques infected with SHIVSF33 also showed higher virus loads than macaques infected with SHIVSF162. Virus persists for over 1 year, as demonstrated by PCR for amplification of viral DNA in all animals and by virus isolation in some animals. Antiviral antibodies, including antibodies to the HIV-1 env glycoprotein (gp160), were detected; titers of antiviral antibodies were higher in macaques infected with SHIVSF33 than in macaques infected with SHIVSF162. Although virus has persisted for over 1 year after inoculation, these animals have remained healthy with no signs of immunodeficiency. These findings demonstrate the utility of the SHIV/macaque model for analyzing HIV-1 env gene functions and for evaluating vaccines based on HIV-1 env antigens.

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At head of title: Department of Commerce. Bureau of Foreign and Domestic Commerce. E.E. Pratt, Chief ...

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At head of title: Department of Commerce. Bureau of Foreign and Domestic Commerce. E.E. Pratt, Chief ...

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In this small paper-bound catalog, Benjamin Welles (1781-1860) listed books in the Harvard College Library which he wished to read. He presumably compiled the list by consulting the Library's 1790 printed catalog, as the works are categorized according to subjects outlined in that catalog (Antiquities, Astronomy, Ancient Authors, Biography, Sacred Criticism, Ethics, Geography, Geometry, History, Nature, Travels / Voyages, Natural Law, Logic, Metaphysics, Miscellaneous Works, Dramatic, Phililogy, Natural Philosophy, Poetry, Rhetoric, and Theology). The final pages of Welles' catalog, which he titles "Another Selection," list additional volumes he wished to read. These are listed alphabetically, A - G. Some titles throughout the catalog have been marked with a "+" perhaps to indicate that Welles had read them.

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A motion that the case not be tried in Suffolk County, on the grounds that the judges and jurors were residents of the colony. Pratt was attorney to Paxton, an attorney and commissioner of customs, who had incurred a debt to the Colony.

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One letter offering information and sources on the judge and poet Benjamin Pratt, including an article in the May 1810 Monthly Anthology and Boston Review.

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Benjamin Welles wrote these six letters to his friend and classmate, John Henry Tudor, between 1799 and 1801. Four of the letters are dated, and the dates of the other two can be deduced from their contents. Welles wrote Tudor four times in September 1799, at the onset of their senior year at Harvard, in an attempt to clear up hurt feelings and false rumors that he believed had caused a chill in their friendship. The cause of the rift is never fully explained, though Welles alludes to "a viper" and "villainous hypocrite" who apparently spread rumors and fueled discord between the two friends. In one letter, Welles asserts that "College is a rascal's Elysium - or the feeling man's hell." In another he writes: "College, Tudor, is a furnace to the phlegmatic, & a Greenland to thee feeling man; it has an atmosphere which breathes contagion to the soul [...] Villains fatten here. College is the embryo of hell." Whatever their discord, the wounds were apparently eventually healed; in a letter written June 26, 1800, Welles writes to ask Tudor about his impending speech at Commencement exercises. In an October 29, 1801 letter, Welles writes to Tudor in Philadelphia (where he appears to have traveled in attempts to recover his failing health) and expresses strong wishes for his friend's recovery and return to Boston. This letter also contains news of their classmate Washington Allston's meeting with painters Henry Fuseli and Benjamin West.

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This layer is a georeferenced raster image of the historic paper map entitled: Seattle Harbor : Puget Sound Washington territory, issued May 1870 C.P. Patterson, superintendant; verification J.E. Hilgard, assistant in charge of the office; triangulation by J. S. Lawson assistant in 1874 based upon the primary triangulation by George Davidson, assistant in 1855-6; topography and hydrography by J.S. Lawson, assistant in 1874 & 5; resurvey of city of Seattle and water front by assist. J.J. Gilbert in 1886; additions by asst. Pratt in 1889; verifications of hydrology by Lieut. Comdr. W. H. Brownson U.S.N. inspector of hydrography. It was published by United States Coast and Geodetic Survey in July 1889. Scale 1:20,000. The image inside the map neatline is georeferenced to the surface of the earth and fit to the Washington State Plane North Coordinate System HARN NAD83 (in Feet) (Fipszone 4601). All map collar and inset information is also available as part of the raster image, including any inset maps, profiles, statistical tables, directories, text, illustrations, index maps, legends, or other information associated with the principal map. This map shows coastal features such as lighthouses, rocks, channels, points, coves, islands, bottom soil types, flats, wharves, and more. Includes also selected land features such as roads, railroads, drainage, land cover, selected buildings, towns, and more. Relief shown by contours and spot heights; depths by soundings. Includes notes, tables, and list of authorities. This layer is part of a selection of digitally scanned and georeferenced historic maps from The Harvard Map Collection as part of the Imaging the Urban Environment project. Maps selected for this project represent major urban areas and cities of the world, at various time periods. These maps typically portray both natural and manmade features at a large scale. The selection represents a range of regions, originators, ground condition dates, scales, and purposes.

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This layer is a georeferenced raster image of the historic paper map entitled: A mapp of the kingdom of Ireland : newly corrected & improv'd by actual observations : divided into its provinces, counties, & baronies, and supply'd with many market towns & other places of note omitted in former mapps ... : together with plans of the citys and fortified towns, as allso a short description of the kingdom by Henry Pratt ; to this map is added a large index of the measur'd distances of ev'ry town from Dublin, of the burroughs, barracks, and post towns with many other improuements and emendations ; I. Harris, sculp. It was published by H. Pratt in 1708. Scale [ca. 1:385,000]. The image inside the map neatline is georeferenced to the surface of the earth and fit to the Irish Grid (Transverse Mercator 1965 (TM-65)) coordinate system. All map collar and inset information is also available as part of the raster image, including any inset maps, profiles, statistical tables, directories, text, illustrations, index maps, legends, or other information associated with the principal map. This map shows features such as drainage, cities and other human settlements, major roads, territorial and administrative boundaries, shoreline features, and more. Relief shown pictorially. Includes also text, index, 16 ancillary town maps, and inset: The sea coasts of Great Britain and Ireland.This layer is part of a selection of digitally scanned and georeferenced historic maps from the Harvard Map Collection. These maps typically portray both natural and manmade features. The selection represents a range of originators, ground condition dates, scales, and map purposes.