Ribosomal subunits produced by cold sensitive initiation of protein synthesis.
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Bacterial Proteins↗
Biomedical subjects
P Lu
Publications and source records attributed to P Lu.
An in vivo block in the initiation of protein synthesis.
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Alanine↗
Characterization of immunochemical reaction for human growth hormone with its monoclonal antibody by perfusion protein G affinity chromatography and capillary zone electrophoresis.
An extremely rapid assay technique for antibody-antigen interaction using human growth hormone and its monoclonal antibody as an example has been developed by utilizing Protein G bound to perfusion chromatography matrices. The antibody and antigen were mixed and incubated at different molar ratios by keeping the concentration of antibody constant. The mixture of antibody and antigen solution was then injected onto the Protein G column. The complex of antibody and antigen formed in the sample solution was retained on the Protein G column as was the free antibody. The peak-area and height of the retained complex and antibody linearly increased with the molar concentration of the antigen when it was not in excess of the corresponding stoichiometric amount of antibody, however, those of the retained peak were constant when the concentration of antigen was in excess of that of the antibody. The validity of this method was confirmed by the results of capillary zone electrophoresis. The method developed cannot only be used to determine the biological activity between antibody and its antigen quickly, but also to determine the stoichiometry of immunological reactions between the antibody and antigen when a stable complex of them can be formed.
Antibodies, Monoclonal↗
Perfusion immunoaffinity chromatography and its application in analysis and purification of biomolecules.
Immunoaffinity cartridges have been prepared by immobilizing the monoclonal antibody to bovine growth hormone (bGH) and bovine growth hormone releasing factor (bGRF) on the streptavidin-coated perfusion media. The cartridge-immobilized antibody to bGH has been used for the analysis of standard sample of recombinant bGH (r-bGH). The cartridge immobilized bGRF has been applied for purification of the C-and N-terminal antibodies and their conjugates with horseradish peroxidase. The purity of the antibody fractions purified by bGRF cartridges has been tested by capillary zone electrophoresis. It has been shown that the immunoaffinity cartridges prepared by immobilizing the antigen offer more biological specificity for the purification of antibody than the Protein G cartridges. The stability and life time of the immunoaffinity cartridges are mainly dependent on the stability of the biomolecules immobilized on them. Immunoaffinity cartridges based on the perfusion media offer us the tools for rapid analysis and purification of antigens or antibodies as well as for determination of the biological activity between them at a very low back pressure in the columns.
Animals↗
Lac repressor-operator interaction: N-terminal peptide backbone 1H and 15N chemical shifts upon complex formation with DNA.
When the lac repressor tetramer is bound to its DNA operator, methylation protection shows the nearly symmetric operator half-sites are contracted asymmetrically. This asymmetric binding results from the DNA sequence/structure. The reported structure of lac repressor N-terminal fragment and an 11 base-pair operator left half-site provides no information concerning the effect of asymmetric binding, from left operator half-site to right half-site, upon the polypeptide backbone. We isolated uniformly 15N labeled 56 amino acid wild-type (HP56WT) and 64 residue mutant [Pro3 > Tyr3] (HP64tyr3) lac repressor N-terminal DNA binding fragments for 1H/15N NMR studies with the left and right operators separately. Spectral coincidence of these longer fragments, indicating structural similarity with a protease derived 51 amino acid fragment for which the amide correlations are assigned, allows for assignment of the common amide resonances. For both HP56WT and HP64tyr3, spectral overlap of the amide correlation peaks reveals the polypeptide backbones of the uncomplexed polypeptides are structurally similar. Likewise the complexes of the peptides to the 11 base-pair lac left operator half-site are similar. On the other hand, complexes of HP56WT and the left compared to the right lac operator half-site show different residues of the polypeptide are affected by binding different half-sites of the operator. Thus, the DNA sequence/structure transmits asymmetry to the polypeptide backbone of the interacting protein.
Bacterial Proteins↗
Comparison of tomographic and planar radionuclide ventriculography in the assessment of regional left ventricular function in patients with left ventricular aneurysm before and after surgery.
METHODS AND RESULTS: To compare tomographic and planar radionuclide ventriculography (RNVG) in assessing regional left ventricular (LV) function and predicting improvement in LV ejection fraction (LVEF) after operation in patients with LV aneurysm, 18 patients with aneurysm underwent both tomography and planar RNVG 1 month before and 3 weeks to 6 months after aneurysmectomy and coronary artery bypass grafting. All patients also underwent preoperative contrast angiography at catheterization. The percent shortening of the apical, anterior, lateral, inferior, and basal segments was calculated from tomographic long-axis and short-axis slices and corresponding planar images (anterior and 30- and 70-degree left anterior oblique views). No significant differences in anterior, apical, and lateral percent shortening were apparent before aneurysmectomy between tomographic and planar studies. However, preoperative basal percent shortening was 47% +/- 13% from tomographic and 28% +/- 14% from planar images (p < 0.001). Preoperative tomography generally agreed better with contrast angiographic results than did planar imaging. After aneurysmectomy, basal function improved to 57% +/- 12% (p < 0.01) by tomography. For all patients, LVEF increased from 29% +/- 8% before to 38% +/- 9% (p < 0.01) after aneurysmectomy. However, the greatest improvement (31% +/- 11% to 41% +/- 9%; p < 0.01) was in the 15 patients with greater than 30% basal shortening by tomography before aneurysmectomy; in contrast, no change of LVEF occurred in the three patients with lesser preoperative basal percent shortening. Moreover, greater than 30% basal percent shortening by tomography before aneurysmectomy identified the group most likely to have an increase in LVEF of 5% or more from before to after aneurysmectomy. Prediction of postoperative results was not possible from preoperative planar data. Thus in patients with LV aneurysm, tomographic RNVG appears to provide information that is different and more accurately predictive of results after aneurysmectomy than that available from planar imaging.
Adult↗
Antimyosin antibody imaging in experimental aortic regurgitation.
BACKGROUND: Fiber dropout and myocyte necrosis precede heart failure in experimental aortic regurgitation (AR). The current study aimed to determine whether this process can be detected by noninvasive scintigraphic imaging. METHODS AND RESULTS: 111In-labeled antimyosin antibody Fab fragment (1 to 1.5 mCi) (Myoscint) was administered to each of 34 New Zealand White rabbits: 11 early (3 to 5 weeks) after surgical AR induction; 9 late (98 to 128 weeks) after AR induction; 5 normal and 3 sham-operated age-matched with early AR; and 3 normal and 3 sham-operated age-matched with late AR. Echocardiographic fractional shortening was indistinguishable among control, early AR, and late AR groups. In vivo gamma camera imaging 24 and 48 hours after isotope administration, post-mortem heart activity determination (percentage injected dose per gram), and autoradiography were performed. At 24 and 48 hours, heart-to-lung counts-per-pixel ratios from in vivo images were greater (p < 0.05) in the late AR rabbits than in each of the three other groups. No significant differences were found when early AR and older or younger control rabbits were compared. Heart activity (percentage injected dose per gram) in late AR rabbits trended toward higher values than in age-matched control rabbits (p = 0.057), but in early AR it was indistinguishable from that in the corresponding control (p = 0.413, difference not significant). The autoradiographic endocardial/epicardial activity ratio in late AR rabbits was greater than in control and early AR rabbits (1.27 +/- 0.13 vs 1.06 +/- 0.09 and vs 1.13 +/- 0.10, respectively, p < 0.02). CONCLUSIONS: Whereas isotope uptake in late AR rabbits differed from that in control and early AR rabbits, systolic function was indistinguishable. Thus 111In-labeled antimyosin antibody imaging may permit noninvasive detection of AR-induced myocardial damage before functional deterioration.
Animals↗
The adsorption of lead and copper from aqueous solution on modified peat-resin particles.
Raw peat was modified with sulfuric acid, then mixed modified with resin to prepare the modified peat-resin particles. Using the batch experimental systems, the removal of heavy metals (copper and lead) on the modified peat-resin particles was investigated. The data of the adsorption isotherm could be fitted by the Langmuir equation well. The adsorption rate of heavy metals on modified peat-resin particles was very swift. The removal processes of heavy metals on modified peat-resin particles could be well described by pseudo-second order model. The adsorption rate of lead was affected by the initial heavy metal concentration, initial pH, particle size, agitation speed and particle mass. In the adsorption of heavy metals (lead and copper) on the modified peat-resin particles, ion exchange was the major reaction mechanism. Desorption data showed that the lead adsorbed by modified peat-resin particle could be desorbed by 0.5 N or 1.0 N HNO3. The desorption rate was swift. The experiments indicated that the modified peat-resin particles have great potential for the removal of heavy metals from wastewater.
Adsorption↗
Accumulation of rare earth elements in corn after agricultural application.
Using both pot and plot experiments, the dose-dependent accumulation of rare earth elements (REs) in corn (Zea mays L.) after application of an agricultural REs mixture was measured. In the pot experiment, the dose-dependent accumulation of REs in corn root and stem was observed, but it could not be detected in corn leaf under the dosage of 20 mg REs kg(-1) soil (oven-dry mass). The non-observed effect concentration (NOEC) for accumulation of REs in corn seedling with the pot experiment was 1.0 mg REs kg(-1). In the plot experiment, the dose-dependent accumulation was observed at an early stage after application of REs and the NOEC value of 32 mg REs m(-2) was obtained. At harvest, no dose-dependent accumulation of REs was observed in any part of the corn. These results can be confirmed by the fingerprinting analysis based on the differences between La to RE ratios in the REs mixture and in pot or plot soil. We observed that the plant shows no preference on individual RE and the results of fingerprinting indicated clearly the incorporation of exogenous REs in plant tissues, in a similar manner as that observed in the dose-dependent distribution of RE concentrations. The results indicated also a translocation process of REs from plant root to leaf when applied to soil or from leaf to root when applied to leaf. A homeostatic regulation mechanism for excessive uptake of REs in plants is suggested to regulate the concentrations of REs in the plant.
Agriculture↗
Biosolids effects on phosphorus retention and release in some sandy Florida soils.
The soil solid phase components most responsible for P sorption in Florida soils are Fe and Al oxides. Thus, we hypothesized that land application of biosolids would significantly increase a soil's P retention by increasing its content of P-sorbing solids, especially when biosolids with high Fe and Al concentrations are applied to soils that sorb P poorly. Biosolids effects were quantified by a series of single-point isotherms on soils from two field studies sampled for up to 4 yr after initial biosolids application. Biosolids additions had little effect on P retention in a soil with abundant oxalate-extractable Fe and Al and a correspondingly large native P-sorbing capacity. However, biosolids significantly increased P retention in a soil with low oxalate-extractable Fe and Al content and low native P-sorbing capacity. Biosolids effects on P retention lasted 1 to 3 yr after application, depending on biosolids source and rate of application, and generally mimicked persistence of increased extractable Fe and Al concentrations in the poorly P-sorbing soil. Disappearance of added Fe and Al (and, hence, P retention capacity) from the surface horizons over time was relatively rapid, perhaps due to abundant organic acid production associated with biosolids degradation. Phosphorus in biosolids containing (or tailored to contain) abundant Fe and/or Al can be expected to behave as a slowly available P source, and to be less subject to leaching losses than completely soluble P sources.
Absorption↗
Influence of water treatment residuals on phosphorus solubility and leaching.
Laboratory and greenhouse studies compared the ability of water treatment residuals (WTRs) to alter P solubility and leaching in Immokalee sandy soil (sandy, siliceous, hyperthermic Arenic Alaquod) amended with biosolids and triple superphosphate (TSP). Aluminum sulfate (Al-WTR) and ferric sulfate (Fe-WTR) coagulation residuals, a lime softening residual (Ca-WTR) produced during hardness removal, and pure hematite were examined. In equilibration studies, the ability to reduce soluble P followed the order Al-WTR > Ca-WTR = Fe-WTR >> hematite. Differences in the P-fixing capacity of the sesquioxide-dominated materials (Al-WTR, Fe-WTR, hematite) were attributed to their varying reactive Fe- and Al-hydrous oxide contents as measured by oxalate extraction. Leachate P was monitored from greenhouse columns where bahiagrass (Paspalum notatum Flugge) was grown on Immokalee soil amended with biosolids or TSP at an equivalent rate of 224 kg P ha(-1) and WTRs at 2.5% (56 Mg ha(-1)). In the absence of WTRs, 21% of TSP and 11% of Largo cake biosolids total phosphorus (PT) leached over 4 mo. With co-applied WTRs, losses from TSP columns were reduced to 3.5% (Fe-WTR), 2.5% (Ca-WTR), and <1% (Al-WTR) of applied P. For the Largo biosolids treatments all WTRs retarded downward P flux such that leachate P was not statistically different than for control (soil only) columns. The phosphorus saturation index (PSI = [Pox]/ [Al(ox) + Fe(ox)], where Pox, Al, and Fe(ox) are oxalate-extractable P, Al, and Fe, respectively) based on a simple oxalate extraction of the WTR and biosolids is potentially useful for determining WTR application rates for controlled reduction of P in drainage when biosolids are applied to low P-sorbing soils.
Alum Compounds↗