Search results for "Bacteriophage lambda"
showing 6 items of 6 documents
Restriction analysis of lambda EMBL3 background recombinants: occurrence of lambda phages carrying a head to tail oriented left arm DNA sequence.
1989
Eight representative recombinant background clones of lambda EMBL3 were analysed using KpnI, BamHI, SalI, EcoRI and HindIII digestion. We found that lambda EMBL3 carries its own left arm in the BamHI cloning site. In the way, recombinant molecules were found to be generated which can grow on Escherichia coli strain NM539. In all cases analysed, the left arm DNA was inserted in a head to tail orientation. Seven clones carried a restored BamHI site at the cos site-BamHI site connection. In the region where the inserted left arm and the right arm were ligated, BamHI cloning produces a large palindromic sequence consisting of two polylinkers. This BamHI site was incompletely cleaved in all case…
A new assay for O6-alkylguanine-DNA-alkyltransferase to determine DNA repair capacities using lambda-phage DNA as substrate.
1990
One O6-methylguanine (O6-meG) was introduced into each BamHI site of lambda-phage DNA as a substrate for the determination of the DNA repair protein O6-alkylguanine-DNA-alkyltransferase. A new assay using as the detection group 32P-labeled phosphate introduced at the 3' position of the modified nucleoside by incorporation of 32P-labeled TTP in the 3'-neighboring position proved highly sensitive: 10(-16) mol of the DNA lesion was still easily detectable. This DNA, which has greater than 1000 bp represents a good model for cellular DNA and was used as a substrate to measure the individual repair capacities for O6-meG in human lymphocytes of 20 healthy male and female donors. There were great …
Dynamics of gene regulatory networks and their dependence on network topology and quantitative parameters – the case of phage λ
2019
Background Gene regulatory networks can be modelled in various ways depending on the level of detail required and biological questions addressed. One of the earliest formalisms used for modeling is a Boolean network, although these models cannot describe most temporal aspects of a biological system. Differential equation models have also been used to model gene regulatory networks, but these frameworks tend to be too detailed for large models and many quantitative parameters might not be deducible in practice. Hybrid models bridge the gap between these two model classes – these are useful when concentration changes are important while the information about precise concentrations and binding…
SeroGRID: an improved method for the rapid selection of antigens with disease related immunogenicity
2003
Screening of cDNA expression libraries derived from human tumors with autologous sera (SEREX) permits the definition of immunogenic antigens in individual cancer patients. However, only a minority of SEREX-derived cDNA clones show a clear cancer-relatedness in the sense that circulating autoantibodies to them occur exclusively in the sera of tumor patients but not in healthy individuals. Evaluation of multiple SEREX-defined clones in serological assays using panels of allogeneic sera from cancer patients as well as appropriate control groups is an important step towards focussing on the relevant antigens. This in turn is the basis for defining disease parameters of diagnostic and prognostic…
Evaluation of T7 and lambda phage display systems for survey of autoantibody profiles in cancer patients.
2008
In the current study we attempted to evaluate the suitability of T7 Select 10-3b and lambdaKM8 phage display systems for the identification of antigens eliciting B cell responses in cancer patients and the production of phage-displayed antigen microarrays that could be exploited for the monitoring of autoantibody profiles. Members of 15 tumour-associated antigen (TAA) families were cloned into both phage display vectors and the TAA mini-libraries were immunoscreened with 22 melanoma patients' sera resulting in the detection of reactivity against members of 5 antigen families in both systems, yet with variable sensitivity. T7 phage display system showed greater sensitivity for the detection …
New insights into the regulatory mechanisms of ppGpp and DksA on Escherichia coli RNA polymerase-promoter complex
2015
The stringent response modulators, guanosine tetraphosphate (ppGpp) and protein DksA, bind RNA polymerase (RNAP) and regulate gene expression to adapt bacteria to different environmental conditions. Here, we use Atomic Force Microscopy and in vitro transcription assays to study the effects of these modulators on the conformation and stability of the open promoter complex (RPo) formed at the rrnA P1, rrnB P1, its discriminator (dis) variant and lambda pR promoters. In the absence of modulators, RPo formed at these promoters show different extents of DNA wrapping which correlate with the position of UP elements. Addition of the modulators affects both DNA wrapping and RPo stability in a promo…