background and objectives: dna ladder contains dna fragments of different length but with known size, used to determine the size of unknown dna molecules. different dna ladders are available for expected dna length. conserved sequences were selected for design of primers to generate dna fragments of known specific size. materials and methods: in this study, we describe a method by which dna lad...

objective: dna markers are one of the most important indicators for estimating molecular weight of dna samples, although it used in widespread medical and research laboratories. these markers are very divers and have been prepared in different manners and from different sources of dna. but unfortunately, dna markers haven't been made in our country and all of the markers that we use are made in...

Replicating T5 or lambda phage DNA has been labeled by adding tritiated thymidine for short periods to cultures of phage-infected Escherichia coli before isolation of intracellular DNA. Two procedures are described for separating T5 replicating DNA from DNA of intracellular phage particles. Both T5 and lambda replicating DNA had the same bouyant density in cesium chloride as DNA from phage part...

Procedures for increasing both sensitivity and reproducibility of virus production in disrupted DNA-infected cell preparations have been described. A variety of chemical agents and physical procedures, including fractionation by centrifugation, were tested for effects on the ability of disrupted cell preparations to form virus particles. DNA prepared from lambda-virulent phage, a deletion mutan...

An in vitro system for the production of integrative recombinant DNA of bacteriophage lambda is described. The in vitro recombination mimics the in vivo integration of viral DNA into host DNA in its requirement for int gene product, for the presence of a thermolabile component, and for the limitation of the recombination to a pair of specialized sites (attachment sites) on the DNA. The enzymes ...

We have investigated internal motion of DNA in bacteriophages by measuring fluorescence anisotropy decays of intercalated ethidium. The results showed large suppression of the internal motion of the inner DNA; the interhelix interaction of the DNA in the phage head is considered to enhance the effective viscosity of the DNA rod and to restrict the angle of the internal motion. Considering that ...

In the presence of NADPH and CuCl2, patulin induced the cleavage of ColE1 DNA and lambda phage DNA in vitro. The DNA-cleaving activity of patulin was concentration dependent. At the lowest concentration of patulin, ColE1 supercoiled DNA was relaxed and the highest concentration induced linearization of the DNA. This activity was inhibited by superoxide dismutase, catalase and radical scavengers...

The nucleotide sequence of a 869 bp segment of phage 434 DNA including the regulatory genes cro and cII is presented and compared with the corresponding part of the phage lambda DNA sequence. The 434 cro protein as deduced from the DNA sequence is a highly basic protein of 71 amino acid residues with a calculated molecular weight of 8089. While the cro gene sequences of phage 434 and lambda DNA...

The maturation and packaging of bacteriophage lambda DNA are under the control of the multifunctional viral terminase enzyme, which is composed of the protein products of Nu1 and A, the two most leftward genes of the phage chromosome. Terminase binds selectively to the cohesive end site (cos) of multimeric replicating lambda DNA and introduces staggered nicks to regenerate the 12-base single-st...