Many bacterial outer membrane proteins (OMPs) are missing from two-dimensional (2-D) gel proteome maps. Recently, we developed a technique for 2-D electrophoresis (2-DE) of Escherichia coli OMPs using alkaline pH incubation for isolation of OMPs, followed by improved solubilization conditions for array by 2-DE using immobilized pH gradients. In this report, we expanded our study, examining protein components from the outer membranes of two enteric bacteria, Salmonella typhimurium and Klebsiella pneumoniae (also known as Klebsiella aerogenes), as well as the unrelated, free-living alpha-proteobacteria Caulobacter crescentus. Patterns of OMPs expression appeared remarkably conserved between members of the Enterobacteriaceae, while C. crescentus was unique, displaying a greater number of clusters of higher-molecular-weight proteins (>80 kDa). Peptide mass fingerprinting (PMF) was used for protein identification, and despite matching across-species boundaries, proved useful for first-pass protein assignment of enteric OMPs. In contrast, identification of C. crescentus OMPs was successful only when searching against its recently completed genome. For all three microorganisms examined, the majority of proteins identified on the 2-D gel appear localized to the outer membrane, a result consistent with our previous finding in Escherichia coli. In addition, we discuss some of the benefits and limitations of PMF in cross-species searching. 相似文献
In the present study, a simple, rapid and precise liquid chromatographic method was developed and validated for the simultaneous determination of glimepiride and metformin in sustained release formulation. The separation was achieved on a Nucleosil 100-5SA column, 250 × 4.6 mm i.d., 5 μm using a mobile phase composed of 1.7 % ammonium dihydrogen phosphate buffer pH 3.0: acetonitrile (70:30 v/v).The instrumental settings were a flow rate of 1.0 ml min−1 and a detector wavelength of 230 nm. The retention time of glimepiride and metformin were 5.1 and 11.3, respectively. The developed method was validated in terms of specificity, sensitivity, linearity, range, accuracy, precision and ruggedness. The proposed method was successfully applied to the sustained release pharmaceutical dosage form for the simultaneous determination of glimepiride and metformin without any interference by excipients.
This is the report of Heavy Ion Physics and Quark-Gluon Plasma at WHEPP-09 which was part of Working Group-4. Discussion and
work on some aspects of quark-gluon plasma believed to have created in heavy-ion collisions and in early Universe are reported. 相似文献
This paper proposes a robust sliding mode control strategy for an uncertain nonlinear system subjected to time-varying disturbance. The class of system considered includes state-dependent nonlinearity in the input vector (in addition to the plant matrix). The control scheme uses inertial delay control to estimate the lumped uncertainty. The proposed control enforces sliding without using the discontinuous control and without requiring the knowledge of uncertainties or their bounds. The overall stability of the system is proved. The effectiveness of the proposed strategy is verified for model following and robust performance, by simulation of an illustrative example and an application to inverted pendulum system. 相似文献
A simple, specific, precise and accurate reverse phase liquid chromatographic (RP-LC) method has been developed for the simultaneous determination of etodolac and acetaminophen in tablet dosage form. The chromatographic separation was achieved on a BDS Hypersil C18, 100 mm × 4.6 mm, 5 μm column at a detector wavelength of 274 nm using an isocratic mobile phase consisting of a mixture of 0.05% aqueous orthophosphoric acid and acetonitrile in the ratio of 50:50 (v/v) at a flow rate of 1.0 mL min?1. The retention times for etodolac and acetaminophen were found to be 1.32 and 4.24 min, respectively. The method was validated for the parameters like specificity, linearity, precision, accuracy and robustness. The method was found to be specific and stability indicating as no interfering peaks of impurities, degradent and excipients were observed. The square of correlation coefficients (R2) for etodolac and acetaminophen were 0.9996 and 0.9998 while percentage recoveries were 101.32 and 100.94%, respectively. Intra- and inter-day relative standard deviations for both the components were <2.0%. The proposed RP-LC method can be applied for the routine analysis of commercially available formulations of these drugs either as such or in combination. 相似文献
We describe the synthesis of two novel well-defined tower-shaped 1,3,5-trisubstituted adamantanes 30 and 33 that incorporate a macrocyclic trilactam ring system. Each nanoscale molecule has a broad tripodal base consisting of three identical sulfur-containing termini as the tripod feet, 4-acetylsulfanylmethylphenyl units in the case of 30 and 3,5-bis(acetylsulfanylmethyl)phenyl units in the case of 33. The sulfur atoms are designed to bind the molecules trivalently to the apex of a gold-coated commercial AFM tip through formation of three S-Au bonds. The rigid adamantane-derived head unit with a single hydrogen atom at the apex is designed to scan the sample. Molecules 30 and 33 are synthesized from 1,3,5-triethynyladamantane by a series of Sonogashira coupling reactions involving terminal alkynes and aryl iodides. A macrocyclic trilactam unit is included for added rigidity. We demonstrate that molecule 30 is sufficiently large and rigid to be visualized by a conventional AFM tip. These nanoscale molecules may also find application as chemically well-defined nanoscale objects for calibration of AFM tips. 相似文献
We calculate the Longitudinal Magnetoresistance in the Extreme Quantum Limit (?Ωc ? kBT) for a nondegenerate n-type InSb sample at low temperatures when the dominant energy and momentum loss mechanisms are the el-acoustic phonon and the el-ionized impurity interactions. The magnetic field dependence of the effective mass which is due to the nonparabolic nature of the conduction band as well as the energy and magnetic field dependence of the relaxation time are incorporated in the analysis. Analytical results are presented for both nondegenerate and degenerate samples when individual scattering mechanisms are operative. In general nonparabolicity causes an enhancement in the Longitudinal Magnetoresistance and changes the nature of its magnetic field dependence as compared to the case of a parabolic conduction band. 相似文献