Search results for " plasmid"
showing 10 items of 38 documents
A nanodosimetric model of radiation-induced clustered DNA damage yields
2010
International audience; We present a nanodosimetric model for predicting the yield of double strand breaks (DSBs) and non-DSB clustered damages induced in irradiated DNA. The model uses experimental ionization cluster size distributions measured in a gas model by an ion counting nanodosimeter or, alternatively, distributions simulated by a Monte Carlo track structure code developed to simulate the nanodosimeter. The model is based on a straightforward combinatorial approach translating ionizations, as measured or simulated in a sensitive gas volume, to lesions in a DNA segment of one-two helical turns considered equivalent to the sensitive volume of the nanodosimeter. The two model paramete…
Pheno-genotyping of Salmonella enterica serotype Enteritidis isolates identified in Sicily during a reemergence period.
2005
After an upward trend paralleling that occurring in most European countries, including Italy, since October 2002 Salmonella enterica serotype Enteritidis (S. Enteritidis) has again gained the first position among outbreak and sporadic human isolates of Salmonella in Sicily. Because phage typing of S. Enteritidis has many technical and epidemiological limitations and molecular methods have proved to be poorly discriminative for this organism, multiple typing, using phage typing together with pulsed field gel electrophoresis (PFGE) and plasmid profiling on a sample of fifty human and poultry isolates identified during the period October 2002 to May 2003 in Sicily, was chosen as the most valua…
Development of S/MAR plasmid vector for persistent expression and maintenance in vivo
2007
An ideal gene therapy vector should enable persistent transgene expression without limitations of safety and reproducibility. Here we report the development of a non-viral episomal plasmid DNA (pDNA) vector that appears to fulfil these criteria. This pDNA vector combines a scaffold/matrix attachment region (S/MAR) with a human liver-specific promoter (a1-antitrypsin (AAT)) in such a way that long-term expression is enabled in murine liver following hydrodynamic injection. Long-term expression is demonstrated by monitoring the longitudinal luciferase expression profile for up to 6 months by means of in situ bioluminescent imaging. We conclude that the combination of a mammalian, tissue-speci…
Persistent episomal transgene expression in liver following delivery of a scaffold/matrix attachment region containing non-viral vector
2008
An ideal gene therapy vector should enable persistent transgene expression without limitations of safety and reproducibility. Here we report the development of a non-viral episomal plasmid DNA (pDNA) vector that appears to fulfil these criteria. This pDNA vector combines a scaffold/matrix attachment region (S/MAR) with a human liver-specific promoter (alpha1-antitrypsin (AAT)) in such a way that long-term expression is enabled in murine liver following hydrodynamic injection. Long-term expression is demonstrated by monitoring the longitudinal luciferase expression profile for up to 6 months by means of in situ bioluminescent imaging. All relevant control pDNA constructs expressing luciferas…
Development of S/MAR minicircles for enhanced and persistent transgene expression in the mouse liver.
2010
We have previously described the development of a scaffold/matrix attachment region (S/MAR) episomal vector system for in vivo application and demonstrated its utility to sustain transgene expression in the mouse liver for at least 6 months following a single administration. Subsequently, we observed that transgene expression is sustained for the lifetime of the animal. The level of expression, however, does drop appreciably over time. We hypothesised that by eliminating the bacterial components in our vectors, we could improve their performance since bacterial sequences have been shown to be responsible for the immunotoxicity of the vector and the silencing of its expression when applied i…
Seasonal fluctuations and long-term persistence of pathogenic populations of Agrobacterium spp. in soils.
2002
ABSTRACT Short- and long-term persistence of pathogenic (i.e., tumor forming) agrobacteria in soil was investigated in six nursery plots with a history of high crown gall incidence. No pathogenic Agrobacterium strains were isolated in soil samples taken in fall and winter in any plots, but such strains were isolated from both bulk soils and weed rhizospheres (over 0.5 × 10 5 pathogenic CFU/g of bulk soil or rhizosphere) in three out of six plots in spring and summer. PCR amplifications of a vir sequence from DNA extracted from soil confirmed the presence of Ti plasmids in summer and their absence in fall and winter. The results indicate that strains that harbor a Ti plasmid had an unforesee…
Biotechnological applications of the sepiolite interactions with bacteria: Bacterial transformation and DNA extraction
2020
International audience; Among the various clay minerals, sepiolite, which is a natural nanofibrous silicate that exhibit a poor cell toxicity, is a potential promising nanocarrier for the non-viral and stable transfer of plasmid DNA into bacteria, mammalian and human cells. We first show here that sepiolite binds to bacteria, which can be useful in decontamination protocols. In a previous research we have shown that is possible to modulate the efficiency of the absorption of different types of DNA molecules onto sepiolite, and that the DNA previously adsorbed could be recovered preserving the DNA structure and biological activity. Taking advantage of both, the sepiolite/bacteria and sepioli…
Could subcellular proteomics of root plastids teach us more about mycorrhizal symbiosis?
2007
International audience; The arbuscular mycorrhizal (AM) symbiosis is a mutualistic association between soil-borne fungi and the roots of most plant species. Involving the bilateral exchange of nutrients, the symbiosis is connected to drastic changes in plant cell organelle morphology and physiology. Root plastids, in particular, are forming extensive, network-like structures covering the main symbiotic interface, i.e., intracellular, highly branched haustorium-like fungal structures called arbuscules. These plastid networks are highly dynamic and are formed and degraded concomitantly with the formation and degradation of arbuscules. By producing basic metabolic building blocks like fatty ac…
Midbiotics : conjugative plasmids for genetic engineering of natural gut flora
2019
ABSTRACTThe possibility to modify gut bacterial flora has become an important goal, and various approaches are used to achieve desirable communities. However, the genetic engineering of existing microbes in the gut, which are already compatible with the rest of the community and host immune system, has not received much attention. Here, we discuss and experimentally evaluate the possibility to use modified and mobilizable CRISPR-Cas9-endocing plasmid as a tool to induce changes in bacterial communities. This plasmid system (briefly midbiotic) is delivered from bacterial vector into target bacteria via conjugation. Compared to, for example, bacteriophage-based applications, the benefits of c…