Homology in the transfer origins of broad host range IncP plasmids: Definition of two subgroups of P plasmids

1983 ◽  
Vol 192 (3) ◽  
pp. 436-438 ◽  
Author(s):  
E. Yakobson ◽  
G. Guiney
1981 ◽  
Vol 37 (3) ◽  
pp. 311-316 ◽  
Author(s):  
Neil Willetts ◽  
Carol Crowther

SUMMARYThe broad host-range non-conjugative IncQ plasmid RSF1010 was mobilised with 100% efficiency in membrane filter matings, both inE. coliK12 andP. aeruginosaPAO, by broad host-range conjugative IncP plasmids. No homology between RSF1010 and an IncP plasmid could be detected. InE. coli, IncIα and IncX plasmids, but not IncF, IncN or IncW plasmids, were also relatively efficient at mobilising RSF1010, while inP. aeruginosa, R91–5 (IncP-10) was highly efficient, but pMG5 (IncP-2) and FP2 (IncP-8) were very inefficient. IncP plasmids also mobilised several plasmids derived from RSF1010 for use as in vectors inin vitrorecombination experiments very efficiently, and pSC101 quite efficiently: this reduces the level of biological containment possible with these plasmids.


2003 ◽  
Vol 185 (20) ◽  
pp. 6104-6111 ◽  
Author(s):  
Leonardo J. van Zyl ◽  
Shelly M. Deane ◽  
Douglas E. Rawlings

ABSTRACT Plasmid pTC-F14 is a 14.2-kb plasmid isolated from Acidithiobacillus caldus that has a replicon that is closely related to the promiscuous, broad-host-range IncQ family of plasmids. The region containing the mobilization genes was sequenced and encoded five Mob proteins that were related to those of the DNA processing (Dtr or Tra1) region of IncP plasmids rather than to the three-Mob-protein system of the IncQ group 1 plasmids (e.g., plasmid RSF1010 or R1162). Plasmid pTC-F14 is the second example of an IncQ family plasmid that has five mob genes, the other being pTF-FC2. The minimal region that was essential for mobilization included the mobA, mobB, and mobC genes, as well as the oriT gene. The mobD and mobE genes were nonessential, but together, they enhanced the mobilization frequency by approximately 300-fold. Mobilization of pTC-F14 between Escherichia coli strains by a chromosomally integrated RP4 plasmid was more than 3,500-fold less efficient than the mobilization of pTF-FC2. When both plasmids were coresident in the same E. coli host, pTC-F14 was mobilized at almost the same frequency as pTF-FC2. This enhanced pTC-F14 mobilization frequency was due to the presence of a combination of the pTF-FC2 mobD and mobE gene products, the functions of which are still unknown. Mob protein interaction at the oriT regions was unidirectionally plasmid specific in that a plasmid with the oriT region of pTC-F14 could be mobilized by pTF-FC2 but not vice versa. No evidence for any negative effect on the transfer of one plasmid by the related, potentially competitive plasmid was obtained.


2020 ◽  
Vol 7 (Supplement_1) ◽  
pp. S801-S801
Author(s):  
Jose Alexander ◽  
Daniel Navas ◽  
Marly Flowers ◽  
Angela Charles ◽  
Amy Carr

Abstract Background With the rise of the antimicrobial resistance between different genera and species of bacteria, Phage Therapy is becoming a more realistic and accessible option for patients with limited or no antimicrobial options. Being able to have rapid access to a collection of clinical active phages is key for rapid implementation of phage therapy. The Microbiology Department at AdventHealth Orlando is performing routine screening of environmental and patient samples for isolation of phages against non-fermenting Gram negative bacteria to develop a Phage Bank. Methods Protocols for phage isolation from environmental sources such as lakes, rivers and sewers and clinical samples were developed. A series of respiratory, throat, stool and urine samples were processed following an internal protocol that includes centrifugation, filtration and enrichment. Clinical samples were centrifugated for 10 minutes, filtered using 0.45µm centrifugation filters, seeded with targeted host bacteria (clinical isolates) and incubated at 35°C for 24 hours. The enriched samples were centrifugated and filtered for a final phage enriched solution. Screening and isolation were performed using the Gracia method over trypticase soybean agar (TSA) for plaque morphology and quantification. Host range screening of other clinical isolates of P. aeruginosa was performed using the new isolated and purified phages. Results 4 lytic phages against clinical strains of P. aeruginosa from patient with diagnosis of cystic fibrosis (CF), were isolated and purified from 4 different respiratory samples, including sputum and bronchial alveolar lavage. All phages showed phenotypical characteristics of lytic activity. 1 phage was active against 4 strains of P. aeruginosa, 1 phage was active against 2 strains of P. aeruginosa and the remaining 2 phages were active only against the initial host target strain. Conclusion With this study we demonstrated the potential use of clinical samples as source for isolating active bacteriophages against clinically significant bacteria strains. Clinical samples from vulnerable population of patients with chronic infections are part of our routine “phage-hunting” process to stock and grow our Phage Bank project for future clinical use. Disclosures All Authors: No reported disclosures


2021 ◽  
Vol 21 (1) ◽  
Author(s):  
M. Adamczyk ◽  
E. Lewicka ◽  
R. Szatkowska ◽  
H. Nieznanska ◽  
J. Ludwiczak ◽  
...  

Abstract Background DNA binding KfrA-type proteins of broad-host-range bacterial plasmids belonging to IncP-1 and IncU incompatibility groups are characterized by globular N-terminal head domains and long alpha-helical coiled-coil tails. They have been shown to act as transcriptional auto-regulators. Results This study was focused on two members of the growing family of KfrA-type proteins encoded by the broad-host-range plasmids, R751 of IncP-1β and RA3 of IncU groups. Comparative in vitro and in silico studies on KfrAR751 and KfrARA3 confirmed their similar biophysical properties despite low conservation of the amino acid sequences. They form a wide range of oligomeric forms in vitro and, in the presence of their cognate DNA binding sites, they polymerize into the higher order filaments visualized as “threads” by negative staining electron microscopy. The studies revealed also temperature-dependent changes in the coiled-coil segment of KfrA proteins that is involved in the stabilization of dimers required for DNA interactions. Conclusion KfrAR751 and KfrARA3 are structural homologues. We postulate that KfrA type proteins have moonlighting activity. They not only act as transcriptional auto-regulators but form cytoskeletal structures, which might facilitate plasmid DNA delivery and positioning in the cells before cell division, involving thermal energy.


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