Cellular Response of Escherichia coli to Microgravity and Microgravity Analogue Culture

2016 ◽  
pp. 259-282
Author(s):  
Rachna Singh ◽  
A. C. Matin
Keyword(s):  
Escherichia Coli ◽  
Cellular Response

Mutagenesis and More: umuDC and the Escherichia coli SOS Response

Genetics ◽  
1998 ◽  
Vol 148 (4) ◽  
pp. 1599-1610 ◽  
Author(s):  
Bradley T Smith ◽  
Graham C Walker
Keyword(s):  
Escherichia Coli ◽  
Dna Damage ◽  
Cellular Response ◽  
Sos Response ◽  
Posttranslational Regulation ◽  
E Coli ◽  
Sos Mutagenesis ◽  
Induced Mutagenesis ◽  
Mechanistic Basis ◽  
Increase Cell Survival

Abstract The cellular response to DNA damage that has been most extensively studied is the SOS response of Escherichia coli. Analyses of the SOS response have led to new insights into the transcriptional and posttranslational regulation of processes that increase cell survival after DNA damage as well as insights into DNA-damage-induced mutagenesis, i.e., SOS mutagenesis. SOS mutagenesis requires the recA and umuDC gene products and has as its mechanistic basis the alteration of DNA polymerase III such that it becomes capable of replicating DNA containing miscoding and noncoding lesions. Ongoing investigations of the mechanisms underlying SOS mutagenesis, as well as recent observations suggesting that the umuDC operon may have a role in the regulation of the E. coli cell cycle after DNA damage has occurred, are discussed.

scholarly journals Cellular response to DNA damage is enhanced by the pR plasmid in mouse cells and in Escherichia coli.

1986 ◽  
Vol 6 (2) ◽  
pp. 586-592 ◽  
Author(s):  
L Marcucci ◽  
F Gigliani ◽  
P A Battaglia ◽  
R Bosi ◽  
E Sporeno ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Dna Damage ◽  
Statistical Analysis ◽  
Cellular Response ◽  
Regulatory Mechanism ◽  
Uv Light ◽  
Transformed Cells ◽  
Insertion Mutagenesis ◽  
Mouse Cells ◽  
Inducible Repair

The pR plasmid, which enhances the survival of Escherichia coli C600 exposed to UV light by induction of the SOS regulatory mechanism, showed the same effect when it transformed mouse LTA cells (tk-, aprt-). With Tn5 insertion mutagenesis which inactivates UV functions in the pR plasmid, we recognized two different regions of the plasmid, uvp1 and uvp2. These pR UVR- mutants exhibited the same effect in LTA transformed cells, demonstrating that resistance to UV light, carried by the pR plasmid, was really due to the expression of these two regions, which were also in the mouse cells. Statistical analysis showed that the expression of the uvp1 and uvp2 regions significantly increased (P less than 0.01) the survival upon exposure to UV light in mouse cells and bacteria. These results might suggest the presence of an inducible repair response to DNA damage in mouse LTA cells.

scholarly journals Increase in Furfural Tolerance in Ethanologenic Escherichia coli LY180 by Plasmid-Based Expression ofthyA

2012 ◽  
Vol 78 (12) ◽  
pp. 4346-4352 ◽  
Author(s):  
Huabao Zheng ◽  
Xuan Wang ◽  
Lorraine P. Yomano ◽  
Keelnatham T. Shanmugam ◽  
Lonnie O. Ingram
Keyword(s):  
Escherichia Coli ◽  
Cellular Response ◽  
De Novo ◽  
Content Type ◽  
Genomic Libraries ◽  
Methyl Donor ◽  
E Coli ◽  
Furfural Tolerance ◽  
Small Benefit ◽  
Ethanologenic Escherichia Coli

ABSTRACTFurfural is an inhibitory side product formed during the depolymerization of hemicellulose by mineral acids. Genomic libraries from three different bacteria (Bacillus subtilisYB886,Escherichia coliNC3, andZymomonas mobilisCP4) were screened for genes that conferred furfural resistance on plates. Beneficial plasmids containing thethyAgene (coding for thymidylate synthase) were recovered from all three organisms. Expression of this key gene in thede novopathway for dTMP biosynthesis improved furfural resistance on plates and during fermentation. A similar benefit was observed by supplementation with thymine, thymidine, or the combination of tetrahydrofolate and serine (precursors for 5,10-methylenetetrahydrofolate, the methyl donor for ThyA). Supplementation with deoxyuridine provided a small benefit, and deoxyribose was of no benefit for furfural tolerance. A combination of thymidine and plasmid expression ofthyAwas no more effective than either alone. Together, these results demonstrate that furfural tolerance is increased by approaches that increase the supply of pyrimidine deoxyribonucleotides. However, ThyA activity was not directly affected by the addition of furfural. Furfural has been previously shown to damage DNA inE. coliand to activate a cellular response to oxidative damage in yeast. The added burden of repairing furfural-damaged DNA inE. coliwould be expected to increase the cellular requirement for dTMP. Increased expression ofthyA(E. coli,B. subtilis, orZ. mobilis), supplementation of cultures with thymidine, and supplementation with precursors for 5,10-methylenetetrahydrofolate (methyl donor) are each proposed to increase furfural tolerance by increasing the availability of dTMP for DNA repair.

scholarly journals Cytoplasmic Protein Mobility in Osmotically Stressed Escherichia coli

2008 ◽  
Vol 191 (1) ◽  
pp. 231-237 ◽  
Author(s):  
Michael C. Konopka ◽  
Kem A. Sochacki ◽  
Benjamin P. Bratton ◽  
Irina A. Shkel ◽  
M. Thomas Record ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Cellular Response ◽  
Fluorescent Protein ◽  
Volume Fraction ◽  
E Coli ◽  
Surprising Effect ◽  
Wide Range ◽  
Underlying Causes ◽  
The Mean ◽  
Green Fluorescent

ABSTRACT Facile diffusion of globular proteins within a cytoplasm that is dense with biopolymers is essential to normal cellular biochemical activity and growth. Remarkably, Escherichia coli grows in minimal medium over a wide range of external osmolalities (0.03 to 1.8 osmol). The mean cytoplasmic biopolymer volume fraction (〈φ〉) for such adapted cells ranges from 0.16 at 0.10 osmol to 0.36 at 1.45 osmol. For cells grown at 0.28 osmol, a similar 〈φ〉 range is obtained by plasmolysis (sudden osmotic upshift) using NaCl or sucrose as the external osmolyte, after which the only available cellular response is passive loss of cytoplasmic water. Here we measure the effective axial diffusion coefficient of green fluorescent protein (D GFP) in the cytoplasm of E. coli cells as a function of 〈φ〉 for both plasmolyzed and adapted cells. For plasmolyzed cells, the median D GFP ( \batchmode \documentclass[fleqn,10pt,legalpaper]{article} \usepackage{amssymb} \usepackage{amsfonts} \usepackage{amsmath} \pagestyle{empty} \begin{document} \(D_{GFP}^{m}\) \end{document} ) decreases by a factor of 70 as 〈φ〉 increases from 0.16 to 0.33. In sharp contrast, for adapted cells, \batchmode \documentclass[fleqn,10pt,legalpaper]{article} \usepackage{amssymb} \usepackage{amsfonts} \usepackage{amsmath} \pagestyle{empty} \begin{document} \(D_{GFP}^{m}\) \end{document} decreases only by a factor of 2.1 as 〈φ〉 increases from 0.16 to 0.36. Clearly, GFP diffusion is not determined by 〈φ〉 alone. By comparison with quantitative models, we show that the data cannot be explained by crowding theory. We suggest possible underlying causes of this surprising effect and further experiments that will help choose among competing hypotheses. Recovery of the ability of proteins to diffuse in the cytoplasm after plasmolysis may well be a key determinant of the time scale of the recovery of growth.

scholarly journals Too much of a good thing: Adaption to iron (II) intoxication in Escherichia coli

2021 ◽  
Author(s):  
Misty D Thomas ◽  
Akamu J Ewunkem ◽  
Sada Boyd ◽  
Danielle K Williams ◽  
Adiya Moore ◽  
...  
Keyword(s):  
Gene Expression ◽  
Escherichia Coli ◽  
Cellular Response ◽  
Genomic Analysis ◽  
Multidrug Resistant ◽  
Resistant Bacteria ◽  
Excess Iron ◽  
Expression Studies ◽  
Gene Expression Studies ◽  
K 12

Abstract Background There has been an increased usage of metallic antimicrobial materials to control pathogenic and multidrug resistant bacteria. Yet, there is a corresponding need to know if this usage leads to genetic adaptations that could produce more harmful strains. Methodology Experimental evolution was used to adapt Escherichia coli K-12 MG1655 to excess iron (II) with subsequent genomic analysis. Phenotypic assays and gene expression studies were conducted to demonstrate pleiotropic effects associated with this adaptation and to elucidate potential cellular responses. Results After 200 days of adaptation, populations cultured in excess iron (II), showed a significant increase in 24-hour optical densities compared to controls. Furthermore, these populations showed increased resistance towards other metals (iron (III) and gallium (III)) and to traditional antibiotics (bacitracin, rifampin, chloramphenicol and sulfanilamide). Genomic analysis identified selective sweeps in three genes; fecA, ptsP and ilvG unique to the iron (II) resistant populations, and gene expression studies demonstrated that their cellular response may be to downregulate genes involved in iron transport (cirA and fecA) while increasing the oxidative stress response (oxyR, soxS and soxR) prior to FeSO4 exposure. Conclusions and Implications Together, this indicates that the selected populations can quickly adapt to stressful levels of iron (II). This study is unique in that it demonstrates that E. coli can adapt to environments that contain excess levels of an essential micronutrient while also demonstrating the genomic foundations of the response and the pleiotropic consequences. The fact that adaptation to excess iron also causes increases in general antibiotic resistance is a serious concern.

scholarly journals Influence of temperature on the growth of fecal coliform

2017 ◽  
Vol 6 (1) ◽  
pp. 20-23 ◽  
Author(s):  
Md Shaheduzzaman ◽  
Md Sayedur Rahman ◽  
Ifra Tun Nur
Keyword(s):  
Escherichia Coli ◽  
Fecal Coliform ◽  
Cellular Response ◽  
Culture Media ◽  
Growth Behavior ◽  
Spot Test ◽  
Influence Of Temperature ◽  
Different Temperatures ◽  
Influence Of Temperature On ◽  
Normal Cellular Function

The cellular response against environmental stresses is one of the most highly conserved regulatory features among all organisms. The exposure of cells to stresses such as heat shock leads to the accumulation of partially and fully denatured proteins that interfere with normal cellular function. Present study was designed to examine the growth and physiology of Escherichia coli at different temperatures in our laboratory condition. With a previous observation of Escherichia coli growth cessation by the increase in temperature on different culture media, current study further extended the examination of the influence of temperature on the growth behavior of fecal coliform on minimal media, a slight retardation in the colony and cell morphology was noticed for fecal coliform at 47 °C within 36 hours to 72 hours of incubation. Consistent result was also found in spot test for fecal species at 45°C.Stamford Journal of Microbiology, Vol.6(1) 2016: 20-23

Inhibition effect of kaolinite on the development of antibiotic resistance genes in Escherichia coli induced by sublethal ampicillin and its molecular mechanism

2019 ◽  
Vol 16 (5) ◽  
pp. 347 ◽  
Author(s):  
Xiaolin Lai ◽  
Pingxiao Wu ◽  
Bo Ruan ◽  
Juan Liu ◽  
Zehua Liu ◽  
...  
Keyword(s):  
Public Health ◽  
Escherichia Coli ◽  
Antibiotic Resistance ◽  
Resistance Genes ◽  
Natural Environment ◽  
Cellular Response ◽  
Molecular Mechanisms ◽  
Target Genes ◽  
Antibiotic Resistance Genes ◽  
E Coli

Environmental contextAntibiotic resistance by microorganisms in the natural environment poses a threat to ecosystems and public health. We report findings suggesting kaolinite can effectively inhibit the development of antibiotic resistance genes in microorganisms, and present a new understanding of the molecular mechanisms that promote the development of antibiotic resistance. These results are critical to mitigating environmental and public health risks resulting from the abuse of antibiotics. AbstractAntibiotic resistance and antibiotic resistance genes (ARGs) in the natural environment pose a threat to ecosystems and public health; therefore, better strategies are needed to mitigate the emergence of resistance. This study examined the expression of ARGs in Escherichia coli (E. coli) after exposure to sub-MIC (minimum inhibitory concentration) antibiotics for 15 days in the presence and absence of kaolinite. The results of the real-time polymerase chain reaction (PCR) showed that the expression levels of the eight target genes of E. coli adhering to kaolinite were relatively decreased, and the MIC results also indicated that the final resistance was lower than that of the strains without kaolinite. A close relationship between E. coli and kaolinite was also revealed, as well as a unique interfacial interaction. In addition, the differential protein expression was further analysed to detect proteins and genes associated with ARGs mutations, and then the underlying mechanisms of cell growth and metabolism were identified under low dose ampicillin stress to elucidate the role of kaolinite in the process. Molecular mechanisms analysis determined that when cells adhering to kaolinite were stressed, transport of ampicillin to the periplasmic space was reduced, and the redox metabolism of bacteria was promoted to combat the harsh environment. Moreover, cells synthesised related peptides or proteins under the action of ribosomal proteins to prevent toxic damage. Therefore, this work not only provides new insights into the cellular response to antibiotic stress, but also provides a topic for more research on methods to delay the emergence of ARGs.

scholarly journals Stability of the Osmoregulated Promoter-DerivedproPmRNA Is Posttranscriptionally Regulated by RNase III in Escherichia coli

2015 ◽  
Vol 197 (7) ◽  
pp. 1297-1305 ◽  
Author(s):  
Boram Lim ◽  
Kangseok Lee
Keyword(s):  
Escherichia Coli ◽  
Osmotic Stress ◽  
Cellular Response ◽  
Rna Binding ◽  
Binding Capacity ◽  
Rnase Iii ◽  
Content Type ◽  
Steady State Levels ◽  
The Stability

ABSTRACTThe enzymatic activity ofEscherichia coliendo-RNase III determines the stability of a subgroup of mRNA species, includingbdm,betT, andproU, whose protein products are associated with the cellular response to osmotic stress. Here, we report that the stability ofproPmRNA, which encodes a transporter of osmoprotectants, is controlled by RNase III in response to osmotic stress. We observed that steady-state levels ofproPmRNA and ProP protein are inversely correlated with cellular RNase III activity and, in turn, affect the proline uptake capacity of the cell.In vitroandin vivoanalyses ofproPmRNA revealed RNase III cleavage sites in a stem-loop within the 5′ untranslated region present only inproPmRNA species synthesized from the osmoregulated P1 promoter. Introduction of nucleotide substitutions in the cleavage site identified inhibited the ribonucleolytic activity of RNase III onproPmRNA, increasing the steady-state levels and half-life of the mRNA. In addition, decreased RNase III activity coincided with a significant increase in both the half-life and abundance ofproPmRNA under hyperosmotic stress conditions. Analysis of the RNA bound to RNase III viain vivocross-linking and immunoprecipitation indicated that this phenomenon is related to the decreased RNA binding capacity of RNase III. Our findings suggest the existence of an RNase III-mediated osmoregulatory network that rapidly balances the expression levels of factors associated with the cellular response to osmotic stress inE. coli.IMPORTANCEOur results demonstrate that RNase III activity onproPmRNA degradation is downregulated inEscherichia colicells under osmotic stress. In addition, we show that the downregulation of RNase III activity is associated with decreased RNA binding capacity of RNase III under hyperosmotic conditions. In particular, our findings demonstrate a link between osmotic stress and RNase III activity, underscoring the growing importance of posttranscriptional regulation in modulating rapid physiological adjustment to environmental changes.

scholarly journals Starvation for Different Nutrients in Escherichia coli Results in Differential Modulation of RpoS Levels and Stability

2005 ◽  
Vol 187 (2) ◽  
pp. 434-442 ◽  
Author(s):  
Mark J. Mandel ◽  
Thomas J. Silhavy
Keyword(s):  
Escherichia Coli ◽  
Translational Control ◽  
Cellular Response ◽  
Phosphate Limitation ◽  
Logarithmic Phase ◽  
Differential Modulation ◽  
Glucose Starvation ◽  
Energy Limitation ◽  
Essential Nutrient ◽  
Different Levels

ABSTRACT Levels of RpoS increase upon glucose starvation in Escherichia coli, which leads to the transcription of genes whose products combat a variety of stresses. RpoS stability is a key level of control in this process, as SprE (RssB)-mediated degradation is inhibited under glucose starvation. Starvation for ammonia or phosphate also results in increased stress resistance and induction of RpoS-dependent genes. However, we demonstrate that RpoS levels following ammonia starvation are only slightly increased compared to growing cells and are 10-fold below the levels observed under glucose or phosphate limitation. This difference is largely due to regulated proteolysis of RpoS, as its stability in ammonia-starved cells is intermediate between that in logarithmic-phase cells and glucose-starved cells. Use of an rpoS construct that is devoid of the gene's native transcriptional and translational control regions reveals that stability differences are sufficient to explain the different levels of RpoS observed in logarithmic phase, ammonia starvation, and glucose starvation. Under phosphate starvation, however, rpoS translation is increased. The cellular response to nutrient limitation is much more complex than previously appreciated, as there is not simply one response that is activated by starvation for any essential nutrient. Our data support the hypothesis that SprE activity is the key level at which ammonia and glucose starvation signals are transmitted to RpoS, and they suggest that carbon source and/or energy limitation are necessary for full inactivation of the SprE pathway.

Sign in / Sign up

Export Citation Format

Share Document