Kinetics of the bleomycin A2 damage in vivo to the folded chromosome of Escherichia coli

1983 ◽  
Vol 43 (2) ◽  
pp. 245-251 ◽  
Author(s):  
J.R. Pellon ◽  
A.J. Sinskey ◽  
S.M. Hecht ◽  
R.F. Gomez
Keyword(s):  
Escherichia Coli ◽  
Kinetics Of

Alteration of adipocyte calcium homeostasis by Escherichia coli endotoxin

1985 ◽  
Vol 248 (3) ◽  
pp. R331-R338
Author(s):  
K. M. Nelson ◽  
J. A. Spitzer
Keyword(s):  
Escherichia Coli ◽  
Cell Surface ◽  
Calcium Homeostasis ◽  
Compartmental Analysis ◽  
In Vitro Exposure ◽  
Exchange Kinetics ◽  
Intracellular Binding ◽  
Kinetics Of

The present study evaluated calcium homeostasis in rat adipocytes after either in vivo or in vitro exposure to Escherichia coli endotoxin. Fat cells from endotoxin-treated rats showed an enhanced uptake of 45Ca. In an attempt to differentiate between 45Ca binding to the cell surface and intracellular 45Ca accumulation, adipocytes were exposed to 5 mM LaCl3. The amount of 45Ca remaining associated with lanthanum-treated adipocytes was taken to be located intracellularly and was increased in adipocytes from endotoxin-treated rats. The amount of 45Ca displaced by lanthanum was also increased in adipocytes from endotoxin-treated rats. This suggested that the endotoxin-induced increase of 45Ca accumulation included both cell surface and intracellular binding sites. Compartmental analysis of the exchange kinetics of cell-associated 45Ca with 40Ca in the medium indicated a 77% increase in the size of the cell surface compartment of adipocytes from endotoxin-treated rats compared with controls. In addition, endotoxin treatment altered the flux of calcium from the cells to the medium. In vitro exposure of freshly prepared adipocytes to 250 or 750 micrograms endotoxin/ml did not produce a perturbation of adipocyte calcium homeostasis. The results indicate that endotoxin induces alterations in the ability of adipocytes to regulate calcium translocations, suggesting that some metabolic and hormonal aspects of endotoxins' actions may be mediated through perturbation of cellular calcium homeostasis.

scholarly journals In Vivo Kinetics of Segregation and Polar Retention of MS2-GFP-RNA Complexes in Escherichia coli

2014 ◽  
Vol 106 (9) ◽  
pp. 1928-1937 ◽  
Author(s):  
Abhishekh Gupta ◽  
Jason Lloyd-Price ◽  
Ramakanth Neeli-Venkata ◽  
Samuel M.D. Oliveira ◽  
Andre S. Ribeiro
Keyword(s):  
Escherichia Coli ◽  
In Vivo Kinetics ◽  
Rna Complexes ◽  
Kinetics Of

scholarly journals Restriction-stimulated homologous recombination of plasmids by the RecE pathway of Escherichia coli.

Genetics ◽  
1992 ◽  
Vol 130 (1) ◽  
pp. 37-49 ◽  
Author(s):  
A Nussbaum ◽  
M Shalit ◽  
A Cohen
Keyword(s):  
Escherichia Coli ◽  
Strand Break ◽  
Dsb Repair ◽  
Conversion Frequency ◽  
Break Site ◽  
Recombination Pathway ◽  
Dna Ends ◽  
Kinetics Of ◽  
Recombination Assay

Abstract To test the double-strand break (DSB) repair model in recombination by the RecE pathway of Escherichia coli, we constructed chimeric phages that allow restriction-mediated release of linear plasmid substrates of the bioluminescence recombination assay in infected EcoRI+ cells. Kinetics of DSB repair and expression of recombination products were followed by Southern hybridization and by the bioluminescence recombination assay, respectively. Plasmid recombinants were analyzed with restriction endonucleases. Our results indicate that a DSB can induce more than one type of RecE-mediated recombination. A DSB within the homology induced intermolecular recombination that followed the rules of the DSB repair model: (1) Recombination was enhanced by in vivo restriction. (2) Repair of the break depended on homologous sequences on the resident plasmid. (3) Break-repair was frequently associated with conversion of alleles that were cis to the break. (4) Conversion frequency decreased as the distance from the break increased. (5) Some clones contained a mixture of plasmid recombinants as expected by replication of a heteroduplex in the primary recombinant. The rules of the DSB repair model were not followed when recombination was induced by a DSB outside the homology. Both the cut and the uncut substrates were recipients in conversion events. Recombination events were associated with deletions that spanned the break site, but these deletions did not reach the homology. We propose that a break outside the homology may stimulate a RecE-mediated recombination pathway that does not involve direct participation of DNA ends in the homologous pairing reaction.

scholarly journals In Vivo Transcription Kinetics of a Synthetic Gene Uninvolved in Stress-Response Pathways in Stressed Escherichia coli Cells

PLoS ONE ◽  
2014 ◽  
Vol 9 (9) ◽  
pp. e109005 ◽  
Author(s):  
Anantha-Barathi Muthukrishnan ◽  
Antti Martikainen ◽  
Ramakanth Neeli-Venkata ◽  
Andre S. Ribeiro
Keyword(s):  
Escherichia Coli ◽  
Stress Response ◽  
Synthetic Gene ◽  
Escherichia Coli Cells ◽  
Kinetics Of

scholarly journals Mechanism of bidirectional thermotaxis in Escherichia coli

eLife ◽  
2017 ◽  
Vol 6 ◽  
Author(s):  
Anja Paulick ◽  
Vladimir Jakovljevic ◽  
SiMing Zhang ◽  
Michael Erickstad ◽  
Alex Groisman ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Optimal Growth ◽  
Wild Type ◽  
E Coli ◽  
Physiological Relevance ◽  
Cell Accumulation ◽  
Physical Stimuli ◽  
In Vivo Analysis ◽  
Kinetics Of

In bacteria various tactic responses are mediated by the same cellular pathway, but sensing of physical stimuli remains poorly understood. Here, we combine an in-vivo analysis of the pathway activity with a microfluidic taxis assay and mathematical modeling to investigate the thermotactic response of Escherichia coli. We show that in the absence of chemical attractants E. coli exhibits a steady thermophilic response, the magnitude of which decreases at higher temperatures. Adaptation of wild-type cells to high levels of chemoattractants sensed by only one of the major chemoreceptors leads to inversion of the thermotactic response at intermediate temperatures and bidirectional cell accumulation in a thermal gradient. A mathematical model can explain this behavior based on the saturation-dependent kinetics of adaptive receptor methylation. Lastly, we find that the preferred accumulation temperature corresponds to optimal growth in the presence of the chemoattractant serine, pointing to a physiological relevance of the observed thermotactic behavior.

scholarly journals Violaxanthin conversion by recombinant diatom and plant de-epoxidases, expressed in Escherichia coli – comparative analysis

2019 ◽  
Author(s):  
Monika Olchawa-Pajor ◽  
Monika Bojko ◽  
Wojciech Strzałka ◽  
Kazimierz Strzałka ◽  
Dariusz Latowski
Keyword(s):  
Escherichia Coli ◽  
Open Reading Frames ◽  
Amino Acid Residues ◽  
Metal Affinity ◽  
Comparable Activity ◽  
First Time ◽  
Kinetics Of ◽  
Reading Frames

The purpose of this research was to obtain recombinant violaxanthin de-epoxidases (VDEs) from two species. The first one was VDE of Arabidopsis thaliana (L.) Heynh. (WT Columbia strain) (AtVDE) which in vivo catalyzes conversion of violaxanthin (Vx) to zeaxanthin (Zx) via anteraxanthin (Ax). The second one was VDE of Phaeodactylum tricornutum Bohlin, 1897 (CCAP 1055/1 strain) (PtVDE) which is responsible for de-epoxidation of diadinoxanthin (Ddx) to diatoxanthin (Dtx). As the first step of our experiments, open reading frames coding for studied enzymes were amplified and subsequently cloned into pET-15b plasmid. For recombinant proteins production Escherichia coli Origami b strain was used. The molecular weight of the produced enzymes were estimated approximately at 45kDa and 50kDa for AtVDE and PtVDE, respectively. Both enzymes, purified under native conditions by immobilized metal affinity chromatography, displayed comparable activity in assay mixture and converted up to 90% Vx in 10 min in two steps enzymatic de-epoxidation, irrespective of enzyme origin. No statistically significant differences were observed when kinetics of the reactions catalyzed by these enzymes were compared. Putative role of selected amino-acid residues of AtVDE and PtVDE was also considered. The significance of the first time obtained recombinant PtVDE as a useful tool in various comparative investigations of de-epoxidation reactions in main types of xanthophyll cycles existing in nature are also indicated.

Sign in / Sign up

Export Citation Format

Share Document