Recombinant plasmid mobilization betweenE.colistrains in seven sterile microcosms

1997 ◽  
Vol 43 (6) ◽  
pp. 534-540 ◽  
Author(s):  
P. Lebaron ◽  
P. Bauda ◽  
N. Frank ◽  
M. C. Lett ◽  
B. Roux ◽  
...  
Keyword(s):  
Recombinant Plasmid ◽  
Recombinant Dna ◽  
Transfer Functions ◽  
Genetically Engineered ◽  
Plasmid Transfer ◽  
Transfer Rates ◽  
E Coli ◽  
Attached Biomass ◽  
Plasmid Mobilization ◽  
Dna Plasmid

Transfer by mobilization of a pBR derivative recombinant plasmid lacking transfer functions (oriT+, tra−, mob−) from one E. coli K12 strain to another was investigated in seven sterile microcosms corresponding to different environments. These microcosms were chosen as representative of environments that genetically engineered microorganisms (GEMOs) encounter after accidental release, namely attached biomass in aquatic environments (biofilm), soil, seawater, freshwater, wastewater, mouse gut, and mussel gut. GEMOs survived in the same way as the host strains in all microcosms. Recombinant DNA mobilization occurred in the mouse gut, in sterile soil, and in biofilm. The plasmid transfer rates principally reflected the environmental conditions encountered in each microcosm.Key words: recombinant DNA, plasmid transfer, mobilization, conjugation, microcosm.

Recombinant plasmid retention and expression in bacterial biofilm cultures

1995 ◽  
Vol 31 (1) ◽  
pp. 105-115 ◽  
Author(s):  
James D. Bryers ◽  
Huang Ching-Tsan
Keyword(s):  
Open System ◽  
Dna Sequences ◽  
Recombinant Plasmid ◽  
Recombinant Dna ◽  
Plasmid Stability ◽  
Accumulation Rate ◽  
Bacterial Biofilm ◽  
Stability Factor ◽  
Reporter Protein ◽  
E Coli

Any exposure of plasmid recombinant microorganisms to an open system environment, either inadvertently or intentionally, mandates research into those fundamental organism:plasmid processes that influence plasmid retention, transfer and expression. In open environmental systems a majority of the microbial activity occurs associated with an interface, within thin biological layers consisting of the cells and their insoluble extracellular polymer, layers known as biofilms. Thus any study regarding the fate of recombinant DNA sequences in an open system must consider processes that affect plasmid retention and expression in a biofilm culture. Biofilm cultures were cultivated in a parallel-plate flow cell reactor using E. coli DH5α which contained a recombinant plasmid with a plasmid stability factor, parB, (pTKW106) or without (pMJR1750). Using β-galactosidase as inducible reporter protein, plasmid retention and gene expression of pMJR1750 and pTKW106, in suspended versus biofilm cultures, were studied under different carbo to nitrogen ratios and plasmid induction levels. Recombinant biofilm formation under these environmental conditions was also investigated. Biofilm net accumulation rate of E. coli DH5α (pTKW106) decreases with increasing induction levels. The β-galactosidase production and ratios of β-galactosidase to total protein increase with increasing induction levels. Synthesis rates of total RNA, β-galactosidase mRNA and rRNA in biofilm cultures of E. coli DH5α (pTKW106) increase after induction by IPTG.

Recombinant DNA Plasmid Transmission to Indigenous Organisms during Waste Treatment

1988 ◽  
Vol 20 (11-12) ◽  
pp. 179-184 ◽  
Author(s):  
M. A. Gealt
Keyword(s):  
Gene Transfer ◽  
Dna Sequences ◽  
Dna Hybridization ◽  
Waste Treatment ◽  
Recombinant Dna ◽  
Genetically Engineered ◽  
Environmental Damage ◽  
Bacterial Conjugation ◽  
Genetically Engineered Microorganisms ◽  
Dna Plasmid

The release of genetically engineered microorganisms into the environment will occur because of its importance to industrial and agricultural progress. Since organisms designed for release can be modified to survive only the time necessary for their function, the greatest potential for environmental damage depends upon the capability for mobilization of the genetically engineered DNA sequences (GEDS). Mobilization of GEDS to indigenous wastewater organisms by the process of bacterial conjugation has been demonstrated. This gene transfer, which will occur in a laboratory-scale waste treatment facility (~20 L capacity), depends on the presence of bacteria containing conjugative plasmids, many of which are indigenous to waste water. Sensitive detection of GEDS transfer requires the use of DNA-DNA hybridization. Environmental conditions do affect the frequency of conjugal gene transfer.

Immunogold labeling of CMP-KDO synthetase produced by recombinant E. Coli cells

1987 ◽  
Vol 45 ◽  
pp. 924-925
Author(s):  
F. A. Durum ◽  
R. G. Goldman ◽  
T. J. Bolling ◽  
M. F. Miller
Keyword(s):  
Inclusion Bodies ◽  
Large Scale ◽  
Recombinant Dna ◽  
Test System ◽  
Cell Protein ◽  
Gram Negative Bacteria ◽  
Cytoplasmic Inclusions ◽  
Isolation And Purification ◽  
E Coli ◽  
Low Concentrations

CMP-KDO synthetase (CKS) is an enzyme which plays a key role in the synthesis of LPS, an outer membrane component unique to gram negative bacteria. CKS activates KDO to CMP-KDO for incorporation into LPS. The enzyme is normally present in low concentrations (0.02% of total cell protein) which makes it difficult to perform large scale isolation and purification. Recently, the gene for CKS from E. coli was cloned and various recombinant DNA constructs overproducing CKS several thousandfold (unpublished data) were derived. Interestingly, no cytoplasmic inclusions of overproduced CKS were observed by EM (Fig. 1) which is in contrast to other reports of large proteinaceous inclusion bodies in various overproducing recombinant strains. The present immunocytochemical study was undertaken to localize CKS in these cells.Immune labeling conditions were first optimized using a previously described cell-free test system. Briefly, this involves soaking small blocks of polymerized bovine serum albumin in purified CKS antigen and subjecting them to various fixation, embedding and immunochemical conditions.

Biodecomposition of Phenanthrene and Pyrene by a Genetically Engineered Escherichia coli

2020 ◽  
Vol 14 (2) ◽  
pp. 121-133 ◽  
Author(s):  
Maryam Ahankoub ◽  
Gashtasb Mardani ◽  
Payam Ghasemi-Dehkordi ◽  
Ameneh Mehri-Ghahfarrokhi ◽  
Abbas Doosti ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
High Performance ◽  
Human Cancer ◽  
Genetically Engineered ◽  
Hazardous Substances ◽  
E Coli ◽  
Spiked Soil ◽  
Engineered Escherichia Coli ◽  
Genetically Manipulated ◽  
Hplc Measurement

Background: Genetically engineered microorganisms (GEMs) can be used for bioremediation of the biological pollutants into nonhazardous or less-hazardous substances, at lower cost. Polycyclic aromatic hydrocarbons (PAHs) are one of these contaminants that associated with a risk of human cancer development. Genetically engineered E. coli that encoded catechol 2,3- dioxygenase (C230) was created and investigated its ability to biodecomposition of phenanthrene and pyrene in spiked soil using high-performance liquid chromatography (HPLC) measurement. We revised patents documents relating to the use of GEMs for bioremediation. This approach have already been done in others studies although using other genes codifying for same catechol degradation approach. Objective: In this study, we investigated biodecomposition of phenanthrene and pyrene by a genetically engineered Escherichia coli. Methods: Briefly, following the cloning of C230 gene (nahH) into pUC18 vector and transformation into E. coli Top10F, the complementary tests, including catalase, oxidase and PCR were used as on isolated bacteria from spiked soil. Results: The results of HPLC measurement showed that in spiked soil containing engineered E. coli, biodegradation of phenanthrene and pyrene comparing to autoclaved soil that inoculated by wild type of E. coli and normal soil group with natural microbial flora, were statistically significant (p<0.05). Moreover, catalase test was positive while the oxidase tests were negative. Conclusion: These findings indicated that genetically manipulated E. coli can provide an effective clean-up process on PAH compounds and it is useful for bioremediation of environmental pollution with petrochemical products.

scholarly journals Structural genes for nitrate-inducible formate dehydrogenase in Escherichia coli K-12.

Genetics ◽  
1990 ◽  
Vol 125 (4) ◽  
pp. 691-702 ◽  
Author(s):  
B L Berg ◽  
V Stewart
Keyword(s):  
Escherichia Coli ◽  
Nitrate Reductase ◽  
Formate Dehydrogenase ◽  
Recombinant Dna ◽  
Structural Genes ◽  
Respiratory Pathway ◽  
E Coli ◽  
Formate Oxidation ◽  
Operon Expression ◽  
K 12

Abstract Formate oxidation coupled to nitrate reduction constitutes a major anaerobic respiratory pathway in Escherichia coli. This respiratory chain consists of formate dehydrogenase-N, quinone, and nitrate reductase. We have isolated a recombinant DNA clone that likely contains the structural genes, fdnGHI, for the three subunits of formate dehydrogenase-N. The fdnGHI clone produced proteins of 110, 32 and 20 kDa which correspond to the subunit sizes of purified formate dehydrogenase-N. Our analysis indicates that fdnGHI is organized as an operon. We mapped the fdn operon to 32 min on the E. coli genetic map, close to the genes for cryptic nitrate reductase (encoded by the narZ operon). Expression of phi(fdnG-lacZ) operon fusions was induced by anaerobiosis and nitrate. This induction required fnr+ and narL+, two regulatory genes whose products are also required for the anaerobic, nitrate-inducible activation of the nitrate reductase structural gene operon, narGHJI. We conclude that regulation of fdnGHI and narGHJI expression is mediated through common pathways.

STABILITY OF trp OPERON RECOMBINANT PLASMID IN E. coli

1981 ◽  
pp. 95-100 ◽  
Author(s):  
Tadayuki Imanaka ◽  
Hiroshi Tsunekawa ◽  
Shuichi Aiba
Keyword(s):  
Recombinant Plasmid ◽  
E Coli ◽  
Trp Operon

scholarly journals Escherichia coli as a genetic tool

1985 ◽  
Vol 95 (3) ◽  
pp. 611-618
Author(s):  
Naomi Datta
Keyword(s):  
Escherichia Coli ◽  
Academic Research ◽  
Genetically Engineered ◽  
Cloning And Expression ◽  
Biological Research ◽  
New Techniques ◽  
E Coli ◽  
Genetic Tool ◽  
The Past ◽  
Made In

SUMMARYThe study of Escherichia coli and its plasmids and bacteriophages has provided a vast body of genetical information, much of it relevant to the whole of biology. This was true even before the development of the new techniques, for cloning and analysing DNA, that have revolutionized biological research during the past decade. Thousands of millions of dollars are now invested in industrial uses of these techniques, which all depend on discoveries made in the course of academic research on E. coli. Much of the background of knowledge necessary for the cloning and expression of genetically engineered information, as well as the techniques themselves, came from work with this organism.

Sign in / Sign up

Export Citation Format

Share Document