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1.
Moraxella sp., a native soil organism that grows on p-nitrophenol (PNP), was genetically engineered for the simultaneous degradation of organophosphorus (OP) pesticides and p-nitrophenol (PNP). The truncated ice nucleation protein (INPNC) anchor was used to target the pesticide-hydrolyzing enzyme, organophosphorus hydrolase (OPH), onto the surface of Moraxella sp., alleviating the potential substrate uptake limitation. A shuttle vector, pPNCO33, coding for INPNC-OPH was constructed and the translocation, surface display, and functionality of OPH were demonstrated in both E. coli and Moraxella sp. However, whole cell activity was 70-fold higher in Moraxella sp. than E. coli. The resulting Moraxella sp. degraded organophosphates as well as PNP rapidly, all within 10 h. The initial hydrolysis rate was 0.6 micromol/h/mg dry weight, 1.5 micromol/h/mg dry weight, and 9.0 micromol/h/mg dry weight for methyl parathion, parathion, and paraoxon, respectively. The possibility of rapidly degrading OP pesticides and their byproducts should open up new opportunities for improved remediation of OP nerve agents in the future. 相似文献
2.
The 27 kDa protein, a major component of rat liver gap junctions, was shown to be phosphorylated in vitro by protein kinase C. The stoichiometry of the phosphorylation indicated that approx. 0.33 mol phosphate was incorporated per mol 27 kDa protein. Phosphorylation was entirely dependent on the presence of calcium and was virtually specific for serine residues. For comparison, the gap junction protein was also examined for its phosphorylation by cAMP-dependent protein kinase, the extent of phosphorylation being one-tenth that exerted by protein kinase C. 相似文献
3.
F. Yoshie 《Oecologia》1986,68(3):370-374
Summary Photosynthesis and transpiration were measured simultaneously, under near-optimum and constant environmental conditions, in intact leaves of plants native to the temperate forest region. A linear relationship between photosynthetic rate and stomatal conductance was found in every species tested irrespective of leaf age or season, indicating that the calculated intercellular CO2 concentration and water-use efficiency were fairly constant within a species. The values of intercellular CO2 concentration and water-use efficiency ranged from 221 to 271 l l–1
and 4.46 to 8.20 mol CO2 mmolH2O–1 (6.24±0.90 mol CO2 mmolH2O–1), respectively. The variations in intercellular CO2 concentration and water-use efficiency were not directly related to photosynthetic capacities, life-forms, or microhabitat preferences. The intercellular CO2 concentrations found in this study were close to values reported from cultivated plants and plants native to more arid regions, suggesting a common mechanism to maintain the stomatal conductance proportional to photosynthetic capacity over a wide variety of C3 plants. 相似文献
4.
Binding and crosslinking of 125I-labeled recombinant human tumor necrosis factor to cell surface receptors 总被引:6,自引:0,他引:6
Highly purified recombinant human tumor necrosis factor (TNF) (molecular mass determined as 17 kilodaltons (kDa) by sodium dodecyl sulfate-polyacrylamide gel electrophoresis and as 36 kDa by Sephadex G-100 gel chromatography) was labeled with 125I to a specific activity of 5 microCi/micrograms without appreciable loss of activity. The binding of 125I-TNF to eighteen human and twelve animal cell lines was examined. The binding varied considerably among different cell lines. In most cell lines, the binding was inhibited up to greater than 90% by the addition of a 100-fold excess of unlabeled TNF. Some human and mouse cell lines showed no significant binding above background levels, suggesting that these cell lines had no receptors for TNF. Among the TNF receptor-positive cell lines, there was no direct correlation between the level of specific TNF binding and the level of sensitivity to the cytotoxic or cytostatic effect of TNF. Some cell lines were sensitive to TNF, whereas others were not affected at all by TNF. The TNF receptor-negative cell lines were also resistant to TNF. Therefore, although the existence of TNF receptor seems to be necessary, it does not alone determine cellular sensitivity to TNF. Scatchard analysis of the binding data revealed that human HeLa S3 and THP-1 had about 50,000 and 10,000 receptors/cell with a dissociation constant (KD) of 0.3-0.5 nM, respectively. Similarly, mouse L-929 and L-M cells had about 5,000 receptors/cell with KD of 3-5 nM. 125I-TNF bound to HeLa S3 cells was rapidly internalized at 37 degrees C, presumably by receptor-mediated endocytosis, and degraded to acid-soluble products. The turnover of TNF receptors on HeLA S3 cells seemed to be rapid, since the level of specific binding quickly decreased after treatment with 100 micrograms/ml of cycloheximide at 37 degrees C with a half-life of about 1.5 h. The crosslinking of the cell-bound 125I-TNF with the use of disuccinimidyl suberate yielded a complex of 105 kDa for HeLa S3 and THP-1 cells, and a complex of 100 kDa for U937 cells. The crosslinking was completely inhibited by the addition of a 100-fold excess of unlabeled TNF. Assuming that the complex was due to a one-to-one association of the dimeric form of TNF (34 kDa) with the receptor, we estimated the molecular size of the human TNF receptor to be 71 kDa for HeLa S3 and THP-1, and 66 kDa for U937. 相似文献
5.
6.
Haruko Ogawa Ako Hijikata Maho Amano Kyoko Kojima Hisako Fukushima Ineo Ishizuka Yoshie Kurihara Isamu Matsumoto 《Glycoconjugate journal》1996,13(4):555-566
The oligosaccharide structures ofCry j I, a major allergenic glycoprotein ofCryptomeria japonica (Japanese cedar, sugi), were analysed by 400 MHz1H-NMR and two-dimensional sugar mapping analyses. The four major fractions comprised a series of biantennary complex type N-linked oligosaccharides that share a fucose/xylose-containing core and glucosamine branches including a novel structure with a nongalactosylated fucosylglucosamine branch.Rabbit polyclonal anti-Cry j I IgG antibodies cross-reacted with three different plant glycoproteins having the same or shorter N-linked oligosaccharides asCry j I. ELISA and ELISA inhibition studies with intact glycoproteins, glycopeptides and peptides indicated that both anti-Cry j I IgGs and anti-Sophora japonica bark lectin II (B-SJA-II) IgGs included oligosaccharide-specific antibodies with different specificities, and that the epitopic structures against anti-Cry j I IgGs include a branch containing 1–6 linked fucose and a core containing fucose/xylose, while those against anti-B-SJA-II IgGs include nonreducing terminal mannose residues. The cross-reactivities of human allergic sera to miraculin andClerodendron Trichotomum lectin (CTA) were low, and inhibition studies suggested that the oligosaccharides onCry j I contribute little or only conformationally to the reactivity of specific IgE antibodies.Abbreviations
Cry j I
a major allergenic glycoprotein ofCryptomeria japonica
- B-SJA-II
Sophora japonica bark lectin II
- CTA
Clerodendron trichotomum lectin
- TFMS
trifluoromethanesulfonic acid
- HRP
horseradish peroxidase 相似文献
7.
In the evergreen Fagaceae forests of Japan, an ectomycorrhizal fungusTricholoma bakamatsutake forms shiros or developing mycelial blocks. To determine the physiological characteristics of the mycelial blocks, organic acids of the soil and major nutrient elements of the soil and roots were compared at three types of sites: presently colonized mycelial blocks, previously colonized sites behind the blocks, and uncolonized sites in front of the blocks. The upper part of the mycelial blocks showed the following features compared with the uncolonized site: lower pH (5.1), higher concentrations of oxalic and gluconic acids, lower content of total nitrogen, a similar amount of total carbon, reduced total and available phosphorus, higher content of total calcium and lower content of exchangeable calcium. These findings suggested that the activity of the fungus led to soil acidification by the organic acids, an increase in C/N ratio, depletion of phosphorus and accumulation of calcium. 相似文献
8.
Purification and characterization of phosphoenolpyruvate phosphomutase from Pseudomonas gladioli B-1. 下载免费PDF全文
Phosphoenolpyruvate phosphomutase (PEPPM) catalyzes C-P bond formation by intramolecular rearrangement of phosphoenolpyruvate to phosphonopyruvate (PnPy). We purified PEPPM from a gram-negative bacterium, Pseudomonas gladioli B-1 isolated as a C-P compound producer. The equilibrium of this reaction favors the formation of the phosphate ester by cleaving the C-P bond of PnPy, but the C-P bond-forming reaction is physiologically significant. The C-P bond-forming activity of PEPPM was confirmed with a purified protein. The molecular mass of the native enzyme was estimated to be 263 and 220 kDa by gel filtration and polyacrylamide gel electrophoresis, respectively. A subunit molecular mass of 61 kDa was determined by sodium dodecyl sulfate-polyacrylamide gel electrophoresis, indicating that the native protein was a tetramer. The optimum pH and temperature were 7.5 to 8.0 and 40 degrees C, respectively. The Km value for PnPy was 19 +/- 3.5 microM, and the maximum initial velocity of the conversion of PnPy to phosphoenolpyruvate was 200 microM/s/mg. PEPPM was activated by the presence of the divalent metal ion, and the Km values were 3.5 +/- 1.4 microM for Mg2+, 16 +/- 5 nM for Mn2+, 3.0 +/- 1.5 microM for Zn2+, and 1.2 +/- 0.2 microM for Co2+. 相似文献
9.
Kazuhiro Nakamura Yasuhiro Goto Naoko Yoshie Yoshio Inoue 《International journal of biological macromolecules》1992,14(6):321-325
It was found that an optically active copolyester, poly(3-hydroxybutyrate-co-3-hydroxyvalerate), denoted as P(3HB-co-3HV), is synthesized by Alcaligenes eutrophus H16 from several amino acids under various fermentation conditions. The optimum condition for the biosynthesis from one amino acid, threonine, was investigated and its biosynthetic pathway was discussed on the basis of the relation between the fermentation condition and the co-monomer composition of the produced polyesters. 相似文献
10.