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21.
Khoo S Griffen SC Xia Y Baer RJ German MS Cobb MH 《The Journal of biological chemistry》2003,278(35):32969-32977
22.
Soo K O'Rourke MP Khoo PL Steiner KA Wong N Behringer RR Tam PP 《Developmental biology》2002,247(2):251-270
Loss of Twist function in the cranial mesenchyme of the mouse embryo causes failure of closure of the cephalic neural tube and malformation of the branchial arches. In the Twist(-/-) embryo, the expression of molecular markers that signify dorsal forebrain tissues is either absent or reduced, but those associated with ventral tissues display expanded domains of expression. Dorsoventral organization of the mid- and hindbrain and the anterior-posterior pattern of the neural tube are not affected. In the Twist(-/-) embryo, neural crest cells stray from the subectodermal migratory path and the late-migrating subpopulation invades the cell-free zone separating streams of cells going to the first and second branchial arches. Cell transplantation studies reveal that Twist activity is required in the cranial mesenchyme for directing the migration of the neural crest cells, as well as in the neural crest cells within the first branchial arch to achieve correct localization. Twist is also required for the proper differentiation of the first arch tissues into bone, muscle, and teeth. 相似文献
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A case of gastrointestinal torsion with dilatation in a farm-raised channel catfish (Ictalurus punctatus) was examined at the Thad Cochran National Warmwater Aquaculture Center (Stoneville, Mississippi, USA). The affected fish was a gravid female broodfish, which displayed pale gills and a markedly distended abdomen. Internal examination revealed that the gastrointestinal tract and ovaries were rotated around each other four times in a counterclockwise direction as viewed in right lateral recumbency. The catfish had a markedly distended gastrointestinal tract, pale liver, hypoplastic spleen, hypoplastic swim bladder, and high volume of ascitic fluid. Blood analysis indicated multiple abnormalities, including severe anemia and metabolic acidosis. The etiology of the torsion was uncertain; however, the presence of a hypoplastic swim bladder most likely allowed for increased movement of the gastrointestinal tract and ovaries. When examining cases of abdominal distention in fish, gastrointestinal torsion can be considered among the differential diagnoses. 相似文献
25.
Adenosine is known to modulate cell growth in a variety of mammalian cells either via the activation of receptors or through metabolism. We investigated the effect of adenosine on Baby Hamster Kidney (BHK) cell growth and attempted to determine its mechanism of modulation. In wild-type BHK cells, adenosine evoked a biphasic response in which a low concentration of adenosine (1-5 microM) produced an inhibition of colony formation but at higher concentrations (up to 50 microM) this inhibition was progressively reversed. However, no biphasic response was observed in an "adenosine kinase" deficient BHK mutant, "5a", which suggests that adenosine kinase plays an important role in the modulation of growth response to adenosine. Adenosine receptors did not appear to have a role in regulating cell growth of BHK cells. Specific A1 and A2 receptor antagonists were unable to reverse the effect of adenosine on cell growth. Even though a specific A3 adenosine receptor antagonist MRS-1220 partly reversed the inhibition in colony formation at 1 microM adenosine, it also affected the transport of adenosine. Thus adenosine transport and metabolism appears to play the major role in this modulation of cell growth as 5'-amino-5'-deoxyadenosine, an adenosine kinase inhibitor, reversed the inhibition of cell growth observed at 1 microM adenosine. These results, taken together, would suggest that adenosine modulates cell growth in BHK mainly through its transport and metabolism to adenine nucleotides. 相似文献
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The role of tryptophan residues in the hemolytic activity of stonustoxin,a lethal factor from stonefish (Synanceja horrida) venom 总被引:1,自引:0,他引:1
Stonustoxin (SNTX) is a pore-forming cytolytic lethal factor, isolated from the venom of the stonefish Synanceja horrida, that has potent hemolytic activity. The role of tryptophan residues in the hemolytic activity of SNTX was investigated. Oxidation of tryptophan residues of SNTX with N-bromosuccinimide (NBS) resulted in loss of hemolytic activity. Binding of 8-anilino-1-naphthalenesulphonate (ANS) to SNTX resulted in occlusion of tryptophan residues that resulted in loss of hemolytic activity. Circular dichroism and fluorescence studies indicated that ANS binding resulted in a conformational change of SNTX, in particular, a relocation of surface tryptophan residues to the hydrophobic interior. NBS-modification resulted in oxidised surface tryptophan residues that did not relocate to the hydrophobic interior. These results suggest that native surface tryptophan residues play a pivotal role in the hemolytic activity of STNX, possibly by being an essential component of a hydrophobic surface necessary for pore-formation. This study is the first report on the essentiality of tryptophan residues in the activity of a lytic and lethal factor from a fish venom. 相似文献
28.
Inhibition of PKR activation by the proline-rich RNA binding domain of the herpes simplex virus type 1 Us11 protein 下载免费PDF全文
Upon activation by double-stranded RNA in virus-infected cells, the cellular PKR kinase phosphorylates the translation initiation factor eukaryotic initiation factor 2 (eIF2) and thereby inhibits protein synthesis. The gamma 34.5 and Us11 gene products encoded by herpes simplex virus type 1 (HSV-1) are dedicated to preventing the accumulation of phosphorylated eIF2. While the gamma 34.5 gene specifies a regulatory subunit for protein phosphatase 1 alpha, the Us11 gene encodes an RNA binding protein that also prevents PKR activation. gamma 34.5 mutants fail to grow on a variety of human cells as phosphorylated eIF2 accumulates and protein synthesis ceases prior to the completion of the viral life cycle. We demonstrate that expression of a 68-amino-acid fragment of Us11 containing a novel proline-rich basic RNA binding domain allows for sustained protein synthesis and enhanced growth of gamma 34.5 mutants. Furthermore, this fragment is sufficient to inhibit activation of the cellular PKR kinase in a cell-free system, suggesting that the intrinsic activities of this small fragment, notably RNA binding and ribosome association, may be required to prevent PKR activation. 相似文献
29.
An alkaline inorganic pyrophosphatase (IP) from leaves of an orchid, Aranda Christine 130 (Arachnis hookerana var. luteola × Vanda Hilo Blue) was purified by acetone precipitation and chromatography on Sephadex G-75 and DEAE-cellulose. The IP gave a single band on non-denaturing gel electrophoresis at pH 8.3 and its M, determined by gel filtration, was 28 000. The pH optimum was 9 and the IP required Mg2+ for its activity and stability. The IP exhibited high specificity for PPi and attained a maximum activity at a Mg2+: PPi ratio of 10:1. Other cations tested could not replace Mg2+ and they were also found to be inhibitory. The IP was also inhibited by EDTA and F? but not by iodoacetamide. 相似文献
30.
Kavita Venkataraman Luor Shyuan Maudrene Tan Dianne Carrol Tan Bautista Konstadina Griva Yasmin Laura Marie Zuniga Mohamed Amir Yung Seng Lee Jeannette Lee E. Shyong Tai Eric Yin Hao Khoo Hwee Lin Wee 《PloS one》2015,10(9)