Search results for "PLASMID"
showing 10 items of 327 documents
Plasmid diversity in Vibrio vulnificus biotypes.
2009
Vibrio vulnificus is a heterogeneous bacterial species that can be virulent for humans and fish. Virulence in fish seems to rely on a recently described plasmid that can be transmitted between strains, aided by a conjugative plasmid. The main objective of this work was to analyse the plasmid content of a wide collection of strains from the three biotypes of the species, as well as to identify putative conjugative and virulence plasmids by means of Southern hybridization with specific probes and sequence analysis of selected gene markers. We found 28 different plasmid profiles in a total of 112 strains, which were relatively biotype- or serovar-specific. Biotype 1 lacked high-molecular-mass…
Genetic features of Multi Drug Resistant (MDR) Klebsiella pneumoniae and its Plasmids
2019
Klebsiella pneumoniae, a major cause of both hospital and community-acquired infections, is listed by the World Health Organization as a critical priority antibiotic- resistant bacterial pathogen. With the appearance of sequencing techniques such as Next-generation Sequencing (NGS), there is the possibility to obtain the whole genome of the bacteria, getting to know all antimicrobial resistance determinants. The purpose of this study has been to apply this new technology to clinical microbiology, in order to characterize the resistome present in carbapenem-resistant K.pneumoniae strains isolated in a tertiary hospital in Valencia, Spain. A total of 234 isolates were prepared for whole-genom…
Antitumor Cell-Complex Vaccines Employing Genetically Modified Tumor Cells and Fibroblasts
2014
The present study evaluates the immune response mediated by vaccination with cell complexes composed of irradiated B16 tumor cells and mouse fibroblasts genetically modified to produce GM-CSF. The animals were vaccinated with free B16 cells or cell complexes. We employed two gene plasmid constructions: one high producer (pMok) and a low producer (p2F). Tumor transplant was performed by injection of B16 tumor cells. Plasma levels of total IgG and its subtypes were measured by ELISA. Tumor volumes were measured and survival curves were obtained. The study resulted in a cell complex vaccine able to stimulate the immune system to produce specific anti-tumor membrane proteins (TMP) IgG. In the g…
Fight evolution with evolution: plasmid‐dependent phages with a wide host range prevent the spread of antibiotic resistance
2013
The emergence of pathogenic bacteria resistant to multiple antibiotics is a serious worldwide public health concern. Whenever antibiotics are applied, the genes encoding for antibiotic resistance are selected for within bacterial populations. This has led to the prevalence of conjugative plasmids that carry resistance genes and can transfer themselves between diverse bacterial groups. In this study, we investigated whether it is feasible to attempt to prevent the spread of antibiotic resistances with a lytic bacteriophage, which can replicate in a wide range of gram‐negative bacteria harbouring conjugative drug resistance–conferring plasmids. The counter‐selection against the plasmid was sh…
Plasmid Viability Depends on the Ecological Setting of Hosts within a Multiplasmid Community
2022
Plasmids are extrachromosomal genetic elements, some of which disperse horizontally between different strains and species of bacteria. They are a major factor in the dissemination of virulence factors and antibiotic resistance. Understanding the ecology of plasmids has a notable anthropocentric value, and therefore, the interactions between bacterial hosts and individual plasmids have been studied in detail. However, bacterial systems often carry multiple genetically distinct plasmids, but dynamics within these multiplasmid communities have remained unstudied. Here, we set to investigate the survival of 11 mobilizable or conjugative plasmids under five different conditions where the hosts h…
PRD1-viruksen vaikutus bakteerisoluihin, jotka sisältävät antibioottivastustuskyvyn antavan plasmidin
2010
Antibioottiresistenssi luokitellaan ihmisen terveyden suurimmaksi uhaksi. Antibioottiresistenssi lisääntyy bakteeripopulaatiossa konjugatiivisen plasmidin sisältävien bakteerien välityksellä jopa eri bakteerilajien välillä. PRD1-virus infektoi N-, P- ja W-tyypin konjugatiivisia plasmideja kantavia bakteereja. Tämän työn tarkoituksena oli selvittää, voisiko PRD1-viruksen avulla poistaa bakteeripopulaation vastustuskyky antibiooteille. Tätä testattiin kasvattamalla antibiooteille vastustuskykyisiä bakteereja ilman virusta ja viruksen läsnä ollessa. Bakteerien kasvukäyrät mitattiin lisäksi eri kasvuympäristöissä. Tulosten mukaan virus pudottaa populaation antibioottiresistenssin 100 %:sta jopa…
Indirect Selection against Antibiotic Resistance via Specialized Plasmid-Dependent Bacteriophages
2021
Antibiotic resistance genes of important Gram-negative bacterial pathogens are residing in mobile genetic elements such as conjugative plasmids. These elements rapidly disperse between cells when antibiotics are present and hence our continuous use of antimicrobials selects for elements that often harbor multiple resistance genes. Plasmid-dependent (or male-specific or, in some cases, pilus-dependent) bacteriophages are bacterial viruses that infect specifically bacteria that carry certain plasmids. The introduction of these specialized phages into a plasmid-abundant bacterial community has many beneficial effects from an anthropocentric viewpoint: the majority of the plasmids are lost whil…
Suomalaisesta broilerintuotantoketjusta, broilerinlihasta ja koirista eristettyjen AmpC-positiivisten Escherichia coli -bakteerien resistenssiplasmid…
2014
Molecular evolution of aphids and their primary (Buchnera sp.) and secondary endosymbionts: Implications for the role of symbiosis in insect evolution
2001
Aphids maintain an obligate, endosymbiotic association with Buchnera sp., a bacterium closely related to Escherichia coli. Bacteria are housed in specialized cells of organ-like structures called bacteriomes in the hemocoel of the aphid and are maternally transmitted. Phylogenetic studies have shown that the association had a single origin, dated about 200-250 million years ago, and that host and endosymbiont lineages have evolved in parallel since then. However, the pattern of deepest branching within the aphid family remains unsolved, which thereby hampers an appraisal of, for example, the role played by horizontal gene transfer in the early evolution of Buchnera. The main role of Buchner…