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91.
Harry Walter Gerard B. Nash Galli S. Ascher Herbert J. Meiselman 《Journal of chromatography. B, Analytical technologies in the biomedical and life sciences》1996,680(1-2):197-200
Counter-current distribution (CCD) of red blood cells (RBC) from individuaks with homozygous sickle cell (HbSS) disease in a charge-sensitive aqueous dextran-poly(ethylene glycol) phase system, which fractionates cells on the basis of surface properties, indicates that the percentage of irreversibly sickled cells (ISC) increases and the percentage of reticulocytes decreases with increasing cell partition ratios. The high partition ratios of ISC correspond to those of older RBC when RBC from normal individuals are subjected to CCD. Our results thus indicate that ISC differ in surface properties from those of the bulk of sickle RBC (including reticulocytes) in the population and that the difference is, most likely, charge-related. While the question as to whether ISC are indeed old cells has not yet been unequivocally answered, this view finds support in the fact that the independent parameters of ISC surface properties, as reflected by partition ratios, and densities correlate as they do in older RBC from normal individuals. 相似文献
92.
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94.
Long-term field experiments in Norway spruce stands on fertile sites (site indices 27–35 m) in southwestern Sweden were analysed with respect to volume increment. Three treatments were included (0=No fertilization, N = Fertilization with N, NP = Fertilization with N and P).Volume growth was monitored for 18 years in 10 blocks. No significant differences in annual volume increment between the treatments were detected. Volume increments in the N treatment were 97%, 99% and 107% as high as those in the 0 treatment for the periods 1–5, 6–10 and 11–15 years after the first fertilization. Corresponding values for the NP treatment were 104%, 108% and 110%, indicating that P has a small positive effect.The amount of N-fertilization would correspond to an annual N deposition of 20 kg ha-1 during the next 30 years in southwestern Sweden. For this period, the results imply that this N deposition would not affect the growth of Norway spruce stands on fertile sites. 相似文献
95.
Filamentous fungi are capable of secreting relatively large amounts of heterologous recombinant proteins. Recombinant human glycoproteins expressed in this system, however, carry only carbohydrates of the oligomannose type limiting their potential use in humans. One approach to the problem is genetic engineering of the fungal host to permit production of complex and hybrid N-glycans. UDP-GlcNAc:3-d-mannoside -1,2-N-acetylglucosaminyltransferase I (GnT I) is essential for the conversion of oligomannose to hybrid and complex N-glycans in higher eukaryotic cells. Since GnT I is not produced by fungi, we have introduced into the genome ofAspergillus nidulans the gene encoding full-length rabbit GnT I and demonstrated the expression of GnT I enzyme activity at levels appreciably higher than occurs in most mammalian tissues. All the GnT I activity in theAspergillus transformants remains intracellular suggesting that the rabbit trans-membrane sequence may be capable of targeting GnT I to the fungal Golgi apparatus.Abbreviations CM
complete medium
- Gal-T
UDP-Gal:GlcNAc -1,4-galactosyltransferase (EC 2.4.1.38/90)
- GnT I
UDP-GlcNAc:3-d-mannoside -1,2-N-acetylglucosaminyltransferase I (EC 2.4.1.101)
- HPLC
high performance liquid chromatography
- M3-octyl
Man1-6[Man1-3]Man-octyl
- PAGE
polyacrylamide gel electrophoresis
- MES
2-(N-morpholino)ethane sulfonate
- PCR
polymerase chain reaction
- PEG
polyethylene glycol
- PMSF
phenyl methyl sulfonyl fluoride
- SDS
sodium dodecyl sulfate
- SSC (1×)
0.15m NaCl/0.015m sodium citrate (pH 7.0)
- STC
1.2m sorbitol, 100mm Tris-HCl, pH 7.4, and 10mm CaCl2
- STET
0.1m NaCl, 10mm Tris-HCl, pH 8.0, 1mm EDTA, pH 8.0, 5% Triton-X-100
Deceased. This paper is dedicated to the memory of Lorne S. Reid. 相似文献
96.
Salem Faham Tadashi J. Mizoguchi Elinor T. Adman Harry B. Gray John H. Richards D. C. Rees 《Journal of biological inorganic chemistry》1997,2(4):464-469
Replacement of the cysteine at position 112 of Pseudomonas aeruginosa azurin with an aspartic acid residue results in a mutant (Cys112Asp) protein that retains a strong copper-binding site. CuII(Cys112Asp) azurin can be reduced by excess [RuII(NH3)6]2+, resulting in a CuI protein with an electronic absorption spectrum very similar to that of wild-type CuI azurin. Cys112Asp azurin exhibits reversible interprotein electron-transfer reactivity with P. aeruginosa cytochrome c 551 (μ?=?0.1?M sodium phosphate (pH?7.0);E°(CuII/I)?=?180 mV vs NHE); this redox activity indicates that electrons can still enter and exit the protein through the partially solvent-exposed imidazole ring of His117. The structure of CuII(Cys112Asp) azurin at 2.4-Å resolution shows that the active-site copper is five coordinate: the pseudo-square base of the distorted square-pyramidal structure is defined by the imidazole Nδ atoms of His46 and His117 and the oxygen atoms of an asymmetrically-bound bidentate carboxylate group of Asp112; the apical position is occupied by the oxygen atom of the backbone carbonyl group of Gly45. The CuII–Asp112 interaction is distinguished by an approximately 1.2-Å displacement of the metal center from the plane defined by the Asp112 carboxylate group. 相似文献
97.
Sato Yoji; Weil Max Harry; Tang Wanchun; Sun Shijie; Xie Jianlin; Bisera Joe; Hosaka Hidehiro 《Journal of applied physiology》1997,82(2):558-562
Sato, Yoji, Max Harry Weil, Wanchun Tang, Shijie Sun,Jianlin Xie, Joe Bisera, and Hidehiro Hosaka. EsophagealPCO2 as a monitor of perfusionfailure during hemorrhagic shock. J. Appl.Physiol. 82(2): 558-562, 1997.Measurement ofgastric wall PCO2(PgCO2) bytonometric method has emerged as an attractive option for estimatingvisceral perfusion during circulatory shock. However, gastric acidsecretion obfuscates the tonometric measurement. We, therefore,investigated the option of measuringPCO2 in the esophagus to minimizethese restraints. Hemorrhagic shock was induced in five Sprague-Dawleyrats, and five rats served as sham controls.PgCO2 wasmeasured with an ion-sensitive field effect transistor that wassurgically implanted into the gastric wall. Esophageal luminalPCO2(PeCO2) wasmeasured by a second ion-sensitive field effect transistor sensor.During hemorrhagic shock, mean aortic pressure declined from 150 to 50 mmHg. Gastric blood flow decreased from 58 to 12 ml · min1 · 100 g1 (21% of preshock) andesophageal blood flow from 44 to 7 ml · min1 · 100 g1 (16% of preshock).PgCO2simultaneously increased from 47 to 116 Torr andPeCO2 from 47 to 127 Torr. The increases inPgCO2 werehighly correlated with increases inPeCO2(r = 0.90). Esophageal tonometry may,therefore, serve as a practical alternative to gastric tonometry. 相似文献
98.
Regulation of biosynthesis of the rat liver inner mitochondrial membrane by thyroid hormone 总被引:3,自引:0,他引:3
Regulation of mitochondrial protein synthesis by thyroid hormone has been studied in isolated rat hepatocytes and liver mitochondria. Small doses (5 micrograms/100 g body wt) of triiodothyronine (T3) injected into hypothyroid rats increased both state 3 and 4 respiration by approximately 100%, while the ADP:O ratio remained constant. This suggests that T3 increases the numbers of functional respiratory chain units. T3 also induces mitochondrial protein synthesis by 50-100%. Analysis of the mitochondrial translation products show that all of the products were induced. No differential translation of the peptides involved in the respiratory chain was found. Regulation of the cytoplasmically made inner membrane peptides was also investigated in isolated hepatocytes. The majority of these peptides were not influenced by T3, in contrast to the finding with mitochondrial translation products. Those found to be regulated by T3 belong to two subsets, which were either induced or repressed by hormone. Thus, T3 stimulated a general increase in the synthesis of mitochondrially translated inner membrane peptides, but regulates selectively those inner membrane peptides translated on cytoplasmic ribosomes. The findings suggest that hormone regulation of the respiratory chain is exerted through a few selective proteins, perhaps those which require subunits made from both nuclear and mitochondrial genes. 相似文献
99.
Ronald J. Ash Gary A. Flynn Rob M.J. Liskamp Harry C.J. Ottenheijm 《Biochemical and biophysical research communications》1984,125(2):784-789
Sparsomycin, ScRs configuration, was the most potent of the four possible stereoisomers as a competitive inhibitor of peptide bond formation. In addition, the configuration of the two chiral centers dictated whether the compound exhibited time- and temperature-dependent inhibition of peptidyl transferase when incubated with polysomes prior to enzyme assay. The data corroborate the thesis that a peptidyl transferase-mediated acylation of the pivotal sulfoxide moiety and subsequent Pummerer rearrangement play a significant role in the inhibitory properties of sparsomycin. 相似文献
100.
Buddy Setyono Harry Van Steeg Harry O. Voorma 《Biochimica et Biophysica Acta (BBA) - Gene Structure and Expression》1984,782(3):242-246
Eukaryotic initiation factors (eIF) associate readily with 32P-labeled Semliki Forest virus (SFV) mRNA in vitro, forming complexes which can be crosslinked by 254 nm ultraviolet irradiation. After ribonuclease digestion, the initiation factors were released and analysed by gel electrophoresis. Autoradiography revealed proteins by virtue of crosslinked 32P-labeled mRNA fragments. eIF-4A, -4B and -4C as well as three subunits of eIF-3 could be crosslinked with SFV mRNA. None of these proteins bound to ribosomal RNAs. 相似文献