Project description:Transient plasmid transfection is common approach for studies in cultured mammalian cells. To examine behavior of transfected plasmids, we analyzed their transcriptional landscape by deep sequencing. We found that plasmids generate different levels of transcripts virtually everywhere. Spurious transcription may have undesirable effects as some co-transfected plasmids inhibited expression of luciferase reporters in a dose-dependent manner. In one case, we attributed this effect to kan/neo resistance cassette, which generated a unique population of edited sense and antisense small RNAs. The unexpected complexity of expression of transiently transfected plasmids highlights the importance of appropriate experimental controls.
Project description:Fungi are nature's recyclers, allowing for ecological nutrient cycling and, in turn, the continuation of life on Earth. Some fungi inhabit the human microbiome where they can provide health benefits, while others are opportunistic pathogens that can cause disease. Yeasts, members of the fungal kingdom, have been domesticated by humans for the production of beer, bread, and, recently, medicine and chemicals. Still, the great untapped potential exists within the diverse fungal kingdom. However, many yeasts are intractable, preventing their use in biotechnology or in the development of novel treatments for pathogenic fungi. Therefore, as a first step for the domestication of new fungi, an efficient DNA delivery method needs to be developed. Here, we report the creation of superior conjugative plasmids and demonstrate their transfer via conjugation from bacteria to 7 diverse yeast species including the emerging pathogen Candida auris. To create our superior plasmids, derivatives of the 57 kb conjugative plasmid pTA-Mob 2.0 were built using designed gene deletions and insertions, as well as some unintentional mutations. Specifically, a cluster mutation in the promoter of the conjugative gene traJ had the most significant effect on improving conjugation to yeasts. In addition, we created Golden Gate assembly-compatible plasmid derivatives that allow for the generation of custom plasmids to enable the rapid insertion of designer genetic cassettes. Finally, we demonstrated that designer conjugative plasmids harboring engineered restriction endonucleases can be used as a novel antifungal agent, with important applications for the development of next-generation antifungal therapeutics.
Project description:Antibiotic resistance is exacerbated by the exchange of antibiotic resistance genes (ARGs) between microbes from diverse habitats. Plasmids are important ARGs mobile elements and are spread by horizontal gene transfer (HGT). In this study, we demonstrated the presence of multi-resistant plasmids from inhalable particulate matter (PM) and its effect on gene horizontal transfer. Three transferable multi-resistant plasmids were identified from PM in a hospital, using conjugative mating assays and nanopore sequencing. pTAir-3 contained 26 horizontal transfer elements and 10 ARGs. Importantly pTAir-5 harbored carbapenem resistance gene (blaOXA) which shows homology to plasmids from human and pig commensal bacteria, thus indicating that PM is a media for antibiotic resistant plasmid spread. In addition, 125 μg/mL PM2.5 and PM10 significantly increased the conjugative transfer rate by 110% and 30%, respectively, and augmented reactive oxygen species (ROS) levels. Underlying mechanisms were revealed by identifying the upregulated expressional levels of genes related to ROS, SOS, cell membranes, pilus generation, and transposition via genome-wide RNA sequencing. The study highlights the airborne spread of multi-resistant plasmids and the impact of inhalable PM on the horizontal transfer of antibiotic resistance.
Project description:Transient plasmid transfection is common approach for studies in cultured mammalian cells. To examine behavior of transfected plasmids, we analyzed their transcriptional landscape by deep sequencing. We found that plasmids generate different levels of transcripts virtually everywhere. Spurious transcription may have undesirable effects as some co-transfected plasmids inhibited expression of luciferase reporters in a dose-dependent manner. In one case, we attributed this effect to kan/neo resistance cassette, which generated a unique population of edited sense and antisense small RNAs. The unexpected complexity of expression of transiently transfected plasmids highlights the importance of appropriate experimental controls. HEK293 cells (human origin) transiently transfected with 4 various plasmids
Project description:Plasmids are one of the important mobile genetic elements in bacterial evolution. In this study, to evaluate the generality of the impact of plasmid carriage on host cell between different plasmids, we compared the response of Pseudomonas putida KT2440 to harboring three natural plasmids; RP4 (IncP-1, multidrug resistance, 60,099-bp), pCAR1 (IncP-7, carbazole-degradative, 200,231-bp) and NAH7 (IncP-9, naphthalene-degradative, 82,232-bp). We prepared two sets of plasmid-harboring strains from independent conjugation events to elucidate the reproducibility of the impact of the plasmid carriage. As results, the fitness was reduced by the carriage of RP4 and pCAR1 in liquid medium, while it was unaffected or even improved for NAH7-harboring strains. RP4-harboring KT2440 formed smaller colonies than the plasmid-free strain on solid medium (1.6% agar). The host cells were elongated by the carriage of the all plasmids, respectively. Copy number determination by quantitative PCR showed that the amount of each plasmid DNA in the host cell did not differed drastically. Whole genome resequencing showed that 13 SNPs (RP4), 24 SNPs (pCAR1) and 5 SNPs (NAH7) were the total differences between the two substrains for each plasmid-harboring strains. Transcriptome analyses showed that the impact of plasmid carriage was constantly larger in RP4-harboring strain than the other two plasmid-harboring strains. Genes involved in metal acquisition and metabolism were commonly affected by the carriage of the three plasmid. Indeed, plasmid-harboring strains showed greater growth inhibition than plasmid-free strains under iron-limiting condition. This feature could become future target to control plasmid spreading.
Project description:Plasmid-free Lactococcus lactis IL1403 is one of the best-characterized representatives of lactic acid bacteria (LAB), intensively used in broad microbiology worldwide. Its parent strain, L. lactis IL594, contains seven plasmids (pIL1-pIL7) with resolved DNA sequences and an indicated role for overall plasmid load in enhancing host adaptive potential. To determine how individual plasmids manipulate the expression of phenotypes and chromosomal genes, we conducted global comparative phenotypic analyses combined with transcriptomic studies in plasmid-free L. lactis IL1403, multi-plasmid L. lactis IL594 and its single-plasmid derivatives. The presence of pIL2, pIL4 and pIL5 led to the most pronounced phenotypic differences in the metabolism of several carbon sources, including some β-glycosides and organic acids. The pIL5 plasmid also contributed to increased tolerance to some antimicrobial compounds and heavy metal ions, especially those in the toxic cation group. Comparative transcriptomics showed significant variation in the expression levels of up to 189 chromosomal genes due to the presence of single plasmids, and 435 unique chromosomal genes that are resultant of the activity of all plasmids, which may suggest that the observed phenotypic changes are not only the result of direct action of their own genes, but also originate from indirect actions through cross-talk between plasmids and the chromosome. The data obtained here indicate that plasmid maintenance leads to the development of important mechanisms of global gene regulation that provide changes in the central metabolic pathways and adaptive properties of L. lactis, and suggest the possibility of a similar phenomenon among other groups of bacteria.
Project description:We sampled global bottom up proteomics data from 48 diverse bacteria and searched for sites of lysine acetylation. Bacteria came from 6 phyla: proteobacteria, cyanobacteria, firmicutes, bacteroidetes, actinobacteria, and fibrobacteres.
Project description:The plasmids introduced into the E. coli cells affect the expression of chromosomal genes. Therefore we aimed at comparing the protein expression profiles of a strain not containing any plasmid with strains that do carry plasmids.