With minimalistic circuit design best sound quality is achieved without any compromise. Only one transistor is responsible for amplification of the low MC signals. Overallfeedback, differential amplification and push-pull circuits are not used. Adjustment of the MC imput impedance to the pick-up is superfluous due to the use of a current control circuit. Tubes are only installed where they are able to develop their whole range of advantages: for prevention of natural harmonic spectrum, fusion of neutrality and liveliness as well as the exceptional dynamics. One output transistor guarantees low output impedance to drive long cables without losses ...
article{221460, abstract = {The distribution of the ribosomal RNA (rRNA) genes and three classes of highly repetitive DNA in the chromatin of interphase nuclei of Arabidopsis thaliana was studied for the first time through non-isotopic in situ hybridization and luminescence digital imaging microscopy. Each of the three classes of highly repetitive DNA exhibited a characteristic hybridization pattern, and one class was seen to be primarily localized on two chromocentres, which would allow it to distinguish a particular chromosome. The rDNA was consistently localized on the two largest chromocentres and on one or two smaller chromocentres. A limited number of nuclei exhibited more than four labelled chromocentres, indicative of either polypoidy or differential amplification of the rDNA. In nuclei where the nucleolus could be clearly observed, the nucleolar associated chromocentres (NACs) were seen to be labelled by the ribosomal DNA (rDNA) probe.}, author = {Bauwens, Serge and Van Oostveldt, ...
Main conclusion The most conspicuous difference among chromosomes and genomes in Arachis species, the patternsof heterochromatin, was mainly modeled by differential amplification of different members of one superfamily ofsatellite DNAs.Divergence in repetitive DNA is a primary driving force for genome and chromosome evolution. Section Arachis is karyotypicallydiverse and has six different genomes. Arachis glandulifera (D genome) has the most asymmetric karyotype andthe highest reproductive isolation compared to the well-known A and B genome species. These features make A. glanduliferaan interesting model species for studying the main repetitive components that accompanied the genome and chromosomediversification in the section. Here, we performed a genome-wide analysis of repetitive sequences in A. glandulifera andinvestigated the chromosome distribution of the identified satellite DNA sequences (satDNAs). LTR retroelements, mainlythe Ty3-gypsy families ?Fidel/Feral? and ?Pipoka/Pipa?, were the ...
Frequently present in pancreatic, colorectal and non-small cell lung carcinomas, oncogenic mutant K-Ras must be localised to the plasma membrane (PM) to be functional. Inhibitors of K-Ras PM localisation are therefore putative cancer chemotherapeutics. By screening a microbial extract library in a high conte
Chromosomal evolution, including numerical and structural changes, is a major force in plant diversification and speciation. This study addresses genomic changes associated with the extensive chromosomal variation of the Mediterranean Prospero autumnale complex (Hyacinthaceae), which includes four diploid cytotypes each with a unique combination of chromosome number (x = 5, 6, 7), rDNA loci and genome size....
STRs have become popular DNA markers because they are easily amplified by PCR without the problem of differential amplification; that is, the PCR products for STRs are similar in amount, making analysis easier.. Because of their smaller size, STR alleles can also be separated from other chromosomal locations more easily to ensure closely linked loci are not chosen. Closely linked loci do not follow the predictable pattern of random distribution in the population, making statistical analysis difficult. An individual inherits one copy of an STR from each parent, which may or may not have similar repeat sizes. The number of repeats in STR markers can be highly variable among individuals, which make these STRs effective for human identification purposes.. For human identification and relationship testing purposes, it is important to have DNA markers that exhibit the highest possible variation to discriminate between samples. Our PCR process specifically targets 24 STR markers within the genome (a ...
MAIN CONCLUSION: The most conspicuous difference among chromosomes and genomes in Arachis species, the patterns of heterochromatin, was mainly modeled by differential amplification of different members of one superfamily of satellite DNAs. Divergence in repetitive DNA is a primary driving force for genome and chromosome evolution. Section Arachis is karyotypically diverse and has six different genomes. Arachis glandulifera (D genome) has the most asymmetric karyotype and the highest reproductive isolation compared to the well-known A and B genome species. These features make A. glandulifera an interesting model species for studying the main repetitive components that accompanied the genome and chromosome diversification in the section. Here, we performed a genome-wide analysis of repetitive sequences in A. glandulifera and investigated the chromosome distribution of the identified satellite DNA sequences (satDNAs). LTR retroelements, mainly the Ty3-gypsy families Fidel/Feral and Pipoka/Pipa, ...
The incorporation of dNMPs into DNA by polymerases involves a phosphoryl transfer reaction hypothesized to require two divalent metal ions. Here we investigate this hypothesis using as a model human DNA polymerase lambda (Pol lambda), an enzyme suggested to be activated in vivo by manganese. We report the crystal structures of four complexes of human Pol lambda. In a 1.9 A structure of Pol lambda containing a 3-OH and the non-hydrolyzable analog dUpnpp, a non-catalytic Na+ ion occupies the site for metal A and the ribose of the primer-terminal nucleotide is found in a conformation that positions the acceptor 3-OH out of line with the alpha-phosphate and the bridging oxygen of the pyrophosphate leaving group. Soaking this crystal in MnCl2 yielded a 2.0 A structure with Mn2+ occupying the site for metal A. In the presence of Mn2+, the conformation of the ribose is C3-endo and the 3-oxygen is in line with the leaving oxygen, at a distance from the phosphorus atom of the alpha-phosphate (3.69 A) ...
The transfer of the terminal phosphate of ATP to a material from the sarcoplasmic reticulum of cardiac muscle which can be precipitated by trichloroacetic acid was studied, and the relationship of this biochemical event to active Ca2+ transport was examined. A component of the phosphoryl transfer reaction was stimulated specifically by Ca2+. Both the phosphorylation of the reticulum and the active sequestering of Ca2+ were proportional to the Ca2+ concentration between 10-7 and 10-5M. The time course of both phenomena was similar. These and other observations relating Ca2+-dependent phosphorylation of the membrane of the sarcoplasmic reticulum with the activesequestering of Ca2+ suggest that the phosphoryl transfer reaction may represent the formation of a carrier system which facilitates the inward flux of Ca2+ against a concentration gradient. Cyclic AMP, theophylline, or the combination of these two agents did not influence the rate or extent of the phosphorylation of the sarcoplasmic ...
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AbstractProcedures are proposed for the naming of individual atoms, P, O, F, N, and S in phosphate esters, amidates, thiophosphates, polyphosphates, their mimics, and analogues of transition states for enzyme-catalyzed phosphoryl transfer reactions. Their purpose is to enable scientists in very different fields, e.g. biochemistry, biophysics, chemistry, computational chemistry, crystallography, and molecular biology, to share standard protocols for the labelling of individual atoms in complex molecules. This will facilitate clear and unambiguous descriptions of structural results, as well as scientific intercommunication concerning them. At the present time, perusal of the Protein Data Bank (PDB) and other sources shows that there is a limited degree of commonality in nomenclature, but a large measure of irregularity in more complex structures. The recommendations described here adhere to established practice as closely as possible, in particular to IUPAC and IUBMB recommendations and to
During macronuclear development in hypotrichous ciliated protozoans, several thousand macronuclear DNA molecules are amplified several-hundred fold. We investigated the regulation of this amplification by determining the copy numbers of three different macronuclear DNA molecules in the hypotrichous ciliate Euplotes crassus. Two of the macronuclear DNA molecules were present in approximately 1,000 copies per cell, while the third was present in approximately 6,500 copies per cell. These reiteration levels were achieved either during macronuclear development, or shortly thereafter, and were maintained during vegetative growth. The most abundant macronuclear DNA molecule is present as a single-copy sequence in the micronuclear genome. Thus, its high copy number results from differential amplification. These results indicate that DNA amplification during macronuclear development is regulated individually for each macronuclear DNA molecule.
The law Commission is currently reviewing the Official Information Act 1982 and Local Government Official Information and Meetings Acts 1987. One of the areas they are interested in is sanctions. Currently the Acts are enforced by the Ombudsmen, who make (non-binding, but in practice always obeyed) recommendations on whether information should be released. As most breaches are inadvertent or a result of a misunderstanding of the law, this works reasonably well - but it still provides no real incentive to e.g. respond to requests on time. And as the Law Commission notes that there may be times when an agency sets out to deliberately flout the law, and that proper sanctions may be appropriate. Id like to see this, but given the distributed nature of the work involved in responding to a request, Im not sure if its do-able. And fining some bureaucrat because the Minister is lax about responding to consultation would be grossly unfair. One of the big problems is lateness, and the best solution ...
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TY - JOUR. T1 - Common hydrogen bond interactions in diverse phosphoryl transfer active sites. AU - Summerton, Jean C.. AU - Martin, Gregory M.. AU - Evanseck, Jeffrey D.. AU - Chapman, Michael S.. N1 - Publisher Copyright: © 2014 Summerton et al.. PY - 2014/9/19. Y1 - 2014/9/19. N2 - Phosphoryl transfer reactions figure prominently in energy metabolism, signaling, transport and motility. Prior detailed studies of selected systems have highlighted mechanistic features that distinguish different phosphoryl transfer enzymes. Here, a top-down approach is developed for comparing statistically the active site configurations between populations of diverse structures in the Protein Data Bank, and it reveals patterns of hydrogen bonding that transcend enzyme families. Through analysis of large samples of structures, insights are drawn at a level of detail exceeding the experimental precision of an individual structure. In phosphagen kinases, for example, hydrogen bonds with the O3b of the nucleotide ...