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141.
142.
Characterization of [3H]pentagastrin binding in guinea pig gastric glands--an alternative convenient ligand for receptor binding assay 总被引:2,自引:0,他引:2
R S Chang V J Lotti M E Keegan K A Kunkel 《Biochemical and biophysical research communications》1986,134(2):895-899
The binding of [3H]pentagastrin to guinea pig gastric glands was specific, saturable and of high affinity (Kd = 5 nM). The relative order of potencies for gastrin and CCK analogs in displacing [3H]pentagastrin binding correlated well with those obtained using [125I]gastrin and their reported biological potencies for stimulating acid secretion. Nonselective CCK/gastrin antagonists including carbobenzoxy-CCK (26-32), proglumide and benzotript, but not the selective peripheral CCK antagonist, asperlicin, inhibited specific [3H]pentagastrin binding. The results indicate that [3H]pentagastrin labels physiologically relevant gastrin receptors in guinea pig gastric glands. 相似文献
143.
Mycobacterium avium complex (MAC) is a group of opportunistic pathogens of major public health concern. It is responsible for a wide spectrum of disease dependent on subspecies, route of infection and patients pre-existing conditions. Presently, there is limited research on the incidence of MAC infection that considers both pulmonary and other clinical manifestations. MAC has been isolated from various terrestrial and aquatic environments including natural waters, engineered water systems and soils. Identifying the specific environmental sources responsible for human infection is essential in minimizing disease prevalence. This paper reviews current literature and case studies regarding the wide spectrum of disease caused by MAC and the role of potable water in disease transmission. Potable water was recognized as a putative pathway for MAC infection. Contaminated potable water sources associated with human infection included warm water distribution systems, showers, faucets, household drinking water, swimming pools and hot tub spas. MAC can maintain long-term contamination of potable water sources through its high resistance to disinfectants, association with biofilms and intracellular parasitism of free-living protozoa. Further research is required to investigate the efficiency of water treatment processes against MAC and into construction and maintenance of warm water distribution systems and the role they play in MAC proliferation. 相似文献
144.
George D. Glekas Brendan J. Mulhern Abigail Kroc Keegan A. Duelfer Victor Lei Christopher V. Rao George W. Ordal 《The Journal of biological chemistry》2012,287(47):39412-39418
Bacillus subtilis can perform chemotaxis toward all 20 l-amino acids normally found in proteins. Loss of a single chemoreceptor, McpC, was previously found to reduce chemotaxis to 19 of these amino acids. In this study, we investigated the amino acid-sensing mechanism of McpC. We show that McpC alone can support chemotaxis to 17 of these amino acids to varying degrees. Eleven amino acids were found to directly bind the amino-terminal sensing domain of McpC in vitro. Sequence analysis indicates that the McpC sensing domain exhibits a dual Per-Arnt-Sim (PAS) domain structure. Using this structure as a guide, we were able to isolate mutants that suggest that four amino acids (arginine, glutamine, lysine, and methionine) are sensed by an indirect mechanism. We identified four candidate binding lipoproteins associated with amino acid transporters that may function in indirect sensing: ArtP, GlnH, MetQ, and YckB. ArtP was found to bind arginine and lysine; GlnH, glutamine; MetQ, methionine; and YckB, tryptophan. In addition, we found that ArtP, MetQ, and YckB bind the sensing domain of McpC, suggesting that the three participate in the indirect sensing of arginine, lysine, methionine, and possibly tryptophan as well. Taken together, these results further our understanding of amino acid chemotaxis in B. subtilis and gain insight into how a single chemoreceptor is able to sense many amino acids. 相似文献
145.
Bret S E Heale Liam P Keegan Leeanne McGurk Gracjan Michlewski James Brindle Chloe M Stanton Javier F Caceres Mary A O'Connell 《The EMBO journal》2009,28(20):3145-3156
Adenosine deaminases acting on RNA (ADARs) are best known for altering the coding sequences of mRNA through RNA editing, as in the GluR‐B Q/R site. ADARs have also been shown to affect RNA interference (RNAi) and microRNA processing by deamination of specific adenosines to inosine. Here, we show that ADAR proteins can affect RNA processing independently of their enzymatic activity. We show that ADAR2 can modulate the processing of mir‐376a2 independently of catalytic RNA editing activity. In addition, in a Drosophila assay for RNAi deaminase‐inactive ADAR1 inhibits RNAi through the siRNA pathway. These results imply that ADAR1 and ADAR2 have biological functions as RNA‐binding proteins that extend beyond editing per se and that even genomically encoded ADARs that are catalytically inactive may have such functions. 相似文献
146.
William F. Keegan Scott M. Fitzpatrick Kathleen Sullivan Sealey Michelle J. LeFebvre Peter T. Sinelli 《Human ecology: an interdisciplinary journal》2008,36(5):635-654
Caribbean archaeologists have tended to focus exclusively on the prehistory of the largest islands, perhaps because large
islands are believed to provide the landmass necessary to support long-term population growth and cultural development. Yet,
as research here and elsewhere, e.g., the Pacific, is showing, small islands provided access to resources and landscapes that
were not always readily available on the larger islands. Small islands often have superior terrestrial and, especially, marine
resources; isolated ritual spaces; and more easily defended locations; although they are susceptible to more rapid overexploitation.
This paper examines in detail human needs with regard to island size, demonstrating that small islands were crucial in the
development of pre-Columbian Caribbean societies. Four case studies are presented to illustrate that small islands often were
preferred over large islands throughout the Caribbean archipelagoes. Finally, these studies show that the prehistoric exploitation
and overexploitation of small islands can provide significant insights for establishing baselines that can be used for modern
management and conservation efforts.
相似文献
William F. KeeganEmail: |
147.
LaPorte SL Juo ZS Vaclavikova J Colf LA Qi X Heller NM Keegan AD Garcia KC 《Cell》2008,132(2):259-272
Interleukin-4 and Interleukin-13 are cytokines critical to the development of T cell-mediated humoral immune responses, which are associated with allergy and asthma, and exert their actions through three different combinations of shared receptors. Here we present the crystal structures of the complete set of type I (IL-4R alpha/gamma(c)/IL-4) and type II (IL-4R alpha/IL-13R alpha1/IL-4, IL-4R alpha/IL-13R alpha1/IL-13) ternary signaling complexes. The type I complex reveals a structural basis for gamma(c)'s ability to recognize six different gamma(c)-cytokines. The two type II complexes utilize an unusual top-mounted Ig-like domain on IL-13R alpha1 for a novel mode of cytokine engagement that contributes to a reversal in the IL-4 versus IL-13 ternary complex assembly sequences, which are mediated through substantially different recognition chemistries. We also show that the type II receptor heterodimer signals with different potencies in response to IL-4 versus IL-13 and suggest that the extracellular cytokine-receptor interactions are modulating intracellular membrane-proximal signaling events. 相似文献
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Sohrab?P?Shah Yong?Huang Tao?Xu Macaire?MS?Yuen John?Ling BF?Francis?OuelletteEmail author 《BMC bioinformatics》2005,6(1):34