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Selected AbstractsA simple polyacrylamide gel electrophoresis procedure for separation of polyamidoamine dendrimersELECTROPHORESIS, Issue 16 2003Ajit Sharma Abstract A simple, inexpensive, and rapid electrophoresis technique was developed for use as a routine tool for evaluating purity of polyamidoamine (PAMAM) dendrimers. A variety of factors influencing migration of generations 0,7 dendrimers on nongradient polyacrylamide gels were evaluated. The low generation dendrimers were found to be very sensitive to diffusion during or after electrophoresis. The proposed method incorporates steps that minimize diffusion, in order to obtain improved resolution and sensitivity, especially for the lower-molecular-weight dendrimers. This was accomplished by inclusion of a dendrimer fixation step with glutaraldehyde and performing the electrophoresis separation, fixation, staining, and destaining at 4°C. PAMAM dendrimer separation was studied under basic and acidic conditions. Electrophoresis under acidic conditions gave increased resolution and sensitivity over separation at alkaline pH. Oligomers and trailing generations could be clearly separated and visualized under these conditions. The smallest PAMAM dendrimer, generation 0, was visible at 1.5 ,g under the optimized acidic conditions. With slight modifications, this technique should be applicable to separation of other water-soluble dendrimers. [source] Parameter estimation in selected populations with missing dataJOURNAL OF ANIMAL BREEDING AND GENETICS, Issue 2 2009G. Yagüe-Utrilla Summary This study proposes a procedure to estimate genetic parameters in populations where a selection process results in the loss of an unknown number of observations. The method was developed under the Bayesian inference scope following the missing data theory approach. Its implementation requires slight modifications to the Gibbs sampler algorithm. In order to show the efficiency of this option, a simulation study was conducted. [source] Cloning, sequencing, heterologous expression, and characterization of murine cytochrome P450 3a25*(Cyp3a25), a testosterone 6,-hydroxylaseJOURNAL OF BIOCHEMICAL AND MOLECULAR TOXICOLOGY, Issue 2 2001Ding Dai Abstract A full-length cDNA clone encoding a novel form of the cytochrome P450 3A subfamily (Cyp3a-25) has been isolated from a mouse liver cDNA library. The sequence contained 2010 base pairs and encoded a protein with 503 amino acids. The amino acid sequence shared greater identities with rat CYP3A18 (90%) and golden hamster CYP3A10 (81%) sequences than with known mouse sequences (Cyp3a-11, Cyp3a-13, Cyp3a-16, and Cyp3a-41 [68,70%]). CYP3A25 was expressed in the Escherichia coli PCWori+ expression vector following slight modifications of the N- and C-terminals of the cDNA. The purified CYP3A25 was recognized on an immunoblot by CYP3A1 antibody and has a molecular weight of 50 kD. CYP3A25 was catalytically active in the 6,-hydroxylation of testosterone and the N-demethylation of benzphetamine and erythromycin. It was demonstrated by RT-PCR that the CYP3A25 mRNA is present in both fetal and adult tissues, including liver, lung, intestines, kidney, and brain. Northern blotting demonstrated that expression is greatest in the liver and small intestine. © 2001 John Wiley & Sons, Inc. J Biochem Mol Toxicol 15:90,99, 2001 [source] Top-down proteomics with a quadrupole time-of-flight mass spectrometer and collision-induced dissociationRAPID COMMUNICATIONS IN MASS SPECTROMETRY, Issue 5 2009Andrea Armirotti With slight modifications of the instrumental parameters, we demonstrate that satisfactory top-down data can be obtained with collision-induced dissociation (CID) tandem mass spectrometry on a quadrupole time-of-flight (qTOF) instrument not originally designed for this purpose. Protein identification is achieved with both N- and C-terminal sequence tags and BLAST database searches. The accurate mass measurement of multiply charged fragment ions (mostly y and b-type) supplements the limited set of cleavage sites and provides a high degree of sequence coverage (90,100%). Post-translational modification issues can be addressed too. This approach might help those mass spectrometry (MS) core facilities that are not able to afford very high-resolution instruments, thus expanding the benefits of top-down protein analysis over the worldwide MS community. Copyright © 2009 John Wiley & Sons, Ltd. [source] Clonal composition of the peach-potato aphid Myzus persicae (Homoptera: Aphididae) in France and Scotland: Comparative analysis with IGS fingerprinting and microsatellite markersANNALS OF APPLIED BIOLOGY, Issue 3 2003B FENTON Summary Fourteen colonies of the peach-potato aphid, Myzus persicae, were taken either from French peach trees or weeds in 2001. Thirty five apomictic parthenogenetic lineages (APLs) were established. Ribosomal DNA intergenic spacer (IGS) fingerprinting was used to characterise these and 28 fingerprints were duly obtained. Those lineages with different fingerprints were considered different genotypes and those with the same fingerprint as the same. The genetic identity of APLs was further tested using four microsatellite loci. APLs that differed by IGS fingerprint had distinct microsatellite allele combinations and those that had the same IGS fingerprint had the same microsatellite allele combinations. The results confirmed that IGS types corresponded to different aphid genotypes. Independent APLs with identical IGS and microsatellite genotype were therefore considered different representatives of the same clone. APLs from M. persicae found on Scottish crops in 1995, 1996 and 2001, as well as a long-term laboratory line were also examined by the same methods. Their IGS fingerprints were similar or identical suggesting that they all belonged to the same clone. Microsatellite markers also suggested that these lineages were derived from a single clone. Some field lineages exhibited slight modifications to their IGS fingerprints confirming that the IGS evolves more rapidly than these microsatellite alleles. Thus, IGS will continue to provide a useful marker for aphid fieldwork. [source] The copper(II) complexes di-,-bromo-bis{[2,6-bis(pyrazol-1-yl)pyridine]perchloratocopper(II)} and [2,6-bis(pyrazol-1-yl)pyridine]dibromocopper(II)ACTA CRYSTALLOGRAPHICA SECTION C, Issue 12 2004Surajit Chakrabarty The two title compounds, di-,-bromo-bis{[2,6-bis(pyrazol-1-yl-,N2)pyridine-,N](perchlorato-,O)copper(II)}, [Cu2Br2(ClO4)2(C11H9N5)2], (I), and [2,6-bis(pyrazol-1-yl)pyridine]dibromocopper(II), [CuBr2(C11H9N5)], (II), were synthesized by only slight modifications of the same reaction; compound (II) was formed by adding one molar equivalent of pyrazole (C3N2H4) to the reaction mixture of (I). Compound (I) is a bromo-bridged dinuclear copper(II) compound stabilized by weak interactions with the perchlorate anions (ClO4,), while (II) is a related mononuclear species, which has a distorted square-pyramidal geometry. [source] | |||||||||||||