Search results for "PLASMID"
showing 10 items of 327 documents
Plasmid-mediated QnrS2 determinant from a clinical Aeromonas veronii isolate.
2008
The main objective of this study was to determine the prevalence of the Qnr determinants in clinical and environmental Aeromonas spp. A total of 52 Aeromonas sp. isolates identified by biochemical methods (5), 25 isolated from natural waters (1) and 27 isolated from clinical samples from hospitals in Valencia, Spain, were tested for quinolone resistance by the disk diffusion method (4) (nalidixic acid, 30 μg; oxolinic acid, 2 μg; flumequine, 30 μg; ciprofloxacin, 5 μg; and levofloxacin, 5 μg). Among the studied isolates, 27 showed resistance to nalidixic acid and susceptibility to ciprofloxacin, 24 isolates were susceptible to both nalidixic acid and ciprofloxacin, and only 1, the A. veroni…
Preparation of hepatitis C virus structural and non-structural protein fragments and studies of their immunogenicity
2006
Abstract Plasmids pQE-60 and pQE-30 containing 6× His-tag sequence were used for expression of fragments of HCV structural and non-structural proteins in Escherichia coli (E. coli). The following fragments were used: core (1–98 aa), NS3 (202–482 aa), and tetramer of hypervariable region 1 (HVR1) of E2 protein. The constructed plasmids directed high levels of expression of HCV proteins in E. coli JM109. After purification by the metal-affinity chromatography on nickel–nitrilotriacetic acid (Ni–NTA) agarose, the His-tagged HCV proteins were used for immunization of BALB/c mice. All three proteins were able to induce high levels of specific antibodies and, in the case of the NS3 and HVR1 tetra…
Gold Nanoparticle-Assisted Virus Formation by Means of the Delivery of an Oncolytic Adenovirus Genome
2020
[EN] Oncolytic adenoviruses are a therapeutic alternative to treat cancer based on their ability to replicate selectively in tumor cells. However, their use is limited mainly by the neutralizing antibody (Nab) immune response that prevents repeated dosing. An alternative to facilitate the DNA access to the tumor even in the presence of anti-viral Nabs could be gold nanoparticles able to transfer DNA molecules. However, the ability of these nanoparticles to carry large DNA molecules, such as an oncolytic adenovirus genome, has not been studied. In this work, gold nanoparticles were functionalized with different amounts of polyethylenimine to transfer in a safe and efficient manner a large on…
Cloning of branched chain amino acid biosynthesis genes and assays of alpha-acetolactate synthase activities in Leuconostoc mesenteroides subsp. crem…
1999
Abstract A genomic library from Leuconostoc mesenteroides subsp. cremoris (Lmc) in Escherichia coli was screened for α-acetolactate synthase (ALS) activity using a phenotypic test detecting the production of acetolactate or related C 4 derivatives (diacetyl, acetoin or 2,3-butanediol) in the culture. Four recombinant E. coli clones, with plasmids containing overlapping DNA fragments and displaying anabolic ALS activity, were selected. This activity is encoded by an ilvB gene belonging to a putative operon which contains genes highly similar to the genes of the branched chain amino acid (BCAA) operon of Lactococcus lactis subsp. lactis. This putative BCAA operon is not functional as the ilvA…
Molecular Characterization of the Leucine Plasmid from Buchnera aphidicola , Primary Endosymbiont of the Aphid Acyrthosiphon pisum
2000
The complete sequence of the leucine plasmid of Buchnera aphidicola from the aphid Acyrthosiphon pisum (pLeu-BAp) is reported. Its gene organization was concordant with those of other leucine plasmids of Buchnera from aphids of the Aphidini and Macrosiphini tribes. Three inverted repeats are present in pLeu-BAp. Two of them are also present in pLeu from the family Aphididae: (i) SIR1, located downstream the leucine operon, resembles a rho-independent terminator of transcription, and (ii) LIR1, located upstream of the leucine operon, is suggested to be involved in transcription termination or messenger stability. The third, located near the putative ATGC repeats involved in the origin of rep…
Discovery and molecular characterization of a plasmid localized in Buchnera sp. bacterial endosymbiont of the aphid Rhopalosiphum padi
1995
We have identified and completely sequenced a novel plasmid isolated from the aphid Rhopalosiphum padi. Evidence which suggests that the plasmid occurs localized within the bacterial endosymbionts is presented. The plasmid contains the four genes that constitute the entire leucine operon. This fact makes it really unique since most plasmids are dispensable and lack genes that encode essential anabolic functions. Four more phloem-feeding aphid species also seem to contain homologous plasmids. Although further work is necessary, we hypothesize that this plasmid has appeared during the evolution of the symbiotic association between the aphid and the bacterial endosymbiont. The fact that this p…
Identification and expression of the 11β‐steroid hydroxylase from Cochliobolus lunatus in Corynebacterium glutamicum
2019
Hydroxylation of steroids has acquired special relevance for the pharmaceutical industries. Particularly, the 11β-hydroxylation of steroids is a reaction of biotechnological importance currently carried out at industrial scale by the fungus Cochliobolus lunatus. In this work, we have identified the genes encoding the cytochrome CYP103168 and the reductase CPR64795 of C. lunatus responsible for the 11β-hydroxylase activity in this fungus, which is the key step for the preparative synthesis of cortisol in industry. A recombinant Corynebacterium glutamicum strain harbouring a plasmid expressing both genes forming a synthetic bacterial operon was able to 11β-hydroxylate several steroids as subs…
Expression of a mutant HSP110 sensitizes colorectal cancer cells to chemotherapy and improves disease prognosis
2011
Heat shock proteins (HSPs) are necessary for cancer cell survival. We identified a mutant of HSP110 (HSP110ΔE9) in colorectal cancer showing microsatellite instability (MSI CRC), generated from an aberrantly spliced mRNA and lacking the HSP110 substrate-binding domain. This mutant was expressed at variable levels in almost all MSI CRC cell lines and primary tumors tested. HSP110ΔE9 impaired both the normal cellular localization of HSP110 and its interaction with other HSPs, thus abrogating the chaperone activity and antiapoptotic function of HSP110 in a dominant-negative manner. HSP110ΔE9 overexpression caused the sensitization of cells to anticancer agents such as oxaliplatin and 5-fluorou…
New heteronuclear gold(I)-platinum(II) complexes with cytotoxic properties: are two metals better than one?
2014
A series of mono- and heterodinuclear gold(I) and platinum(II) complexes with a new bipyridylamine-phosphine ligand have been synthesized and characterized. The X-ray structures of the ligand precursor 4-iodo-N,N-di(pyridin-2-yl)benzamide, and of one gold derivative are reported. All the complexes display antiproliferative properties in vitro in human cancer cells in the range of cisplatin or higher, which appear to correlate with compounds' uptake. Interestingly, studies of the interactions of the compounds with models of DNA indicate different mechanisms of actions with respect to cisplatin. The biological activity study of these complexes provides useful information about the interest of…
New chimaeric hepatitis B virus core particles carrying hantavirus (serotype Puumala) epitopes: immunogenicity and protection against virus challenge
1999
Virus-like particles generated by the heterologous expression of virus structural proteins are able to potentiate the immunogenicity of foreign epitopes presented on their surface. In recent years epitopes of various origin have been inserted into the core antigen of hepatitis B virus (HBV) allowing the formation of chimaeric HBV core particles. Chimaeric core particles carrying the 45 N-terminal amino acids of the Puumala hantavirus nucleocapsid protein induced protective immunity in bank voles, the natural host of this hantavirus. Particles applied in the absence of adjuvant are still immunogenic and partially protective in bank voles. Although a C-terminally truncated core antigen of HBV…