Physiological effects of plasmid DNA transformation on Azotobacter vinelandii

1986 ◽  
Vol 32 (2) ◽  
pp. 145-148 ◽  
Author(s):  
Baernard R. Glick ◽  
Heather E. Brooks ◽  
J. J. Pasternak
Keyword(s):  
Plasmid Dna ◽  
Azotobacter Vinelandii ◽  
Genetic Manipulation ◽  
A Priori ◽  
Broad Host Range ◽  
Physiological Effects ◽  
Dna Transformation ◽  
Physiological Changes ◽  
Physiological Processes ◽  
Broad Host Range Plasmid

Genetic transformation of Azotobacter vinelandii by the introduction of broad-host-range plasmid DNA (i.e., pRK2501, RSF1010, or pGSS15) causes a number of physiological changes. As shown here, the capacity for nitrogen fixation, mean cell size, and synthesis of siderophores are decreased, whereas the production of capsular slime is enhanced. These findings suggest that the presence of plasmid DNA imposes a "metabolic load" on Azotobacter vinelandii. Therefore, it cannot be assumed a priori that the introduction of plasmid DNA into Azotobacter vinelandii will not disrupt some normal physiological processes. The implications of these findings are discussed, specifically in the context of developing Azotobacter vinelandii as an effective bacterial fertilizer by genetic manipulation.

Multiple mechanisms for expression of incompatibility by broad-host-range plasmid RK2

1982 ◽  
Vol 152 (3) ◽  
pp. 1078-1090
Author(s):  
R Meyer ◽  
M Hinds
Keyword(s):  
Dna Replication ◽  
Host Range ◽  
Plasmid Dna ◽  
Plasmid Vector ◽  
Broad Host Range ◽  
Plasmid Maintenance ◽  
Broad Host Range Plasmid ◽  
Expression Of Genes ◽  
Plasmid Partitioning ◽  
Plasmid Rk2

By cloning fragments of plasmid DNA, we have shown that RK2 expresses incompatibility by more than one mechanism. One previously identified (R. J. Meyer, Mol. Gen, Genet. 177:155--161, 1979; Thomas et al., Mol. Gen. Genet. 181:1--7, 1981) determinant for incompatibility is linked to the origin of plasmid DNA replication. When cloned into a plasmid vector, this determinant prevents the stable inheritance of a coresident RK2. However, susceptibility to this mechanism of incompatibility requires an active RK2 replicon and is abolished if another replicator is provided. We have also cloned a second incompatibility determinant, encoded within the 54.1- to 56.4-kilobase region of RK2 DNA, which we call IncP-1(II). An RK2 derivative remains sensitive to IncP-1(II), even when it is not replicating by means of the RK2 replicon. The 54.1- to 56.4-kilobase DNA does not confer susceptibility to the IncP-1(II) mechanism, nor does it encode a detectable system for efficient plasmid partitioning. The incompatibility may be related to the expression of genes mapping in the 54.1- to 56.4-kilobase region, which are required for plasmid maintenance and suppression of plasmid-encoded killing functions.

scholarly journals Natural Transformation of Plasmid DNA in Escherichia coli in Sterilized Soil Column

1970 ◽  
Vol 25 (1) ◽  
pp. 49-52
Author(s):  
M Mahabub-Uz-Zaman ◽  
Zia Uddin Ahmed
Keyword(s):  
Escherichia Coli ◽  
Plasmid Dna ◽  
Natural Transformation ◽  
Soil Column ◽  
Limiting Factor ◽  
Broad Host Range ◽  
E Coli ◽  
Competent Cells ◽  
Broad Host Range Plasmid ◽  
Plasmid Puc18

The present study was carried out to assess transformability of natural and laboratory strains of Escherichia coli by plasmid DNA under different transformation conditions in sterilized soil column. Transformation experiments were carried out in laboratory conditions and in sterile soil columns with CaCl2-treated competent cells and non-competent cells at log phase and stationary phase of growth using the broad host range plasmid pUC18. In soil column experiments, transformants were obtained after CaCl2 induced competence in both E. coli K12 DH5α and strain BM09 in the frequency of 10-8 to 10-9. In natural transformation assays, transformants appeared only in log phase cells of strain DH5α at a lower frequency (5.0 x 10-9), and in CaCl2-competent BM09 cells, but not in fresh cells. Thus the major limiting factor for natural transformation in environmental E. coli in soil column is probably the absence of a competent state. The significance of this finding has been discussed with respect to generally observed lower antibiotic resistance in environmental E. coli isolates from aquatic sources. Keywords: Natural transformation; Plasmid DNA; Escherichia coli; Competent stateDOI: http://dx.doi.org/10.3329/bjm.v25i1.4856 Bangladesh J Microbiol, Volume 25, Number 1, June 2008, pp 49-52

scholarly journals Stabilization of the Relaxosome and Stimulation of Conjugal Transfer Are Genetically Distinct Functions of the R1162 Protein MobB

1999 ◽  
Vol 181 (7) ◽  
pp. 2124-2131 ◽  
Author(s):  
Tariq Perwez ◽  
Richard J. Meyer
Keyword(s):  
Plasmid Dna ◽  
Specific Region ◽  
Full Length ◽  
High Rate ◽  
Broad Host Range ◽  
Poor Growth ◽  
Broad Host Range Plasmid ◽  
Plasmid Genes ◽  
The Stability ◽  
Stimulation Of

ABSTRACT MobB is a small protein encoded by the broad-host-range plasmid R1162 and required for efficient mobilization of its DNA during conjugation. The protein was shown previously to stabilize the relaxosome, the complex of plasmid DNA and mobilization proteins at the origin of transfer (oriT). We have generated in-framemobB deletions that specifically inactivate the stabilizing effect of MobB while still allowing a high rate of transfer. Thus, MobB has two genetically distinct functions in transfer. The effect of another deletion, extending into mobA, indicates that both functions require a specific region of MobA protein that is distinct from the nicking-ligating domain. The mobB mutations that specifically affected stability also resulted in poor growth of cells, due to increased transcription from the promoters adjacent tooriT. The effects of the mutations could be suppressed not only by full-length MobB provided in trans, as expected, but also by additional copies of oriT, cloned in pBR322. In addition, in the presence of MobA both the full-length and truncated forms of MobB stimulated recombination betweenoriT-containing plasmids. We propose a model in which MobB regulates expression of plasmid genes by altering the stability of the relaxosome, in a manner that involves the coupling of plasmid molecules.

scholarly journals Transfer of Plasmid DNA to Clinical Coagulase-Negative Staphylococcal Pathogens by Using a Unique Bacteriophage

2015 ◽  
Vol 81 (7) ◽  
pp. 2481-2488 ◽  
Author(s):  
Volker Winstel ◽  
Petra Kühner ◽  
Bernhard Krismer ◽  
Andreas Peschel ◽  
Holger Rohde
Keyword(s):  
Plasmid Dna ◽  
Genetic Manipulation ◽  
Current Knowledge ◽  
Virulence Determinants ◽  
Coagulase Negative Staphylococci ◽  
Reliable Technique ◽  
Content Type ◽  
Research Activities ◽  
Wide Range ◽  
Genetic Barriers

ABSTRACTGenetic manipulation of emerging bacterial pathogens, such as coagulase-negative staphylococci (CoNS), is a major hurdle in clinical and basic microbiological research. Strong genetic barriers, such as restriction modification systems or clustered regularly interspaced short palindromic repeats (CRISPR), usually interfere with available techniques for DNA transformation and therefore complicate manipulation of CoNS or render it impossible. Thus, current knowledge of pathogenicity and virulence determinants of CoNS is very limited. Here, a rapid, efficient, and highly reliable technique is presented to transfer plasmid DNA essential for genetic engineering to important CoNS pathogens from a uniqueStaphylococcus aureusstrain via a specificS. aureusbacteriophage, Φ187. Even strains refractory to electroporation can be transduced by this technique once donor and recipient strains share similar Φ187 receptor properties. As a proof of principle, this technique was used to delete the alternative transcription factor sigma B (SigB) via allelic replacement in nasal and clinicalStaphylococcus epidermidisisolates at high efficiencies. The described approach will allow the genetic manipulation of a wide range of CoNS pathogens and might inspire research activities to manipulate other important pathogens in a similar fashion.

Sign in / Sign up

Export Citation Format

Share Document