Assessment of correlation between physiological states of Escherichia coli cells and their susceptibility to chlorine using flow cytometry

2013 ◽  
Vol 13 (4) ◽  
pp. 1056-1062 ◽  
Author(s):  
Saeid Rezaeinejad ◽  
Volodymyr Ivanov
Keyword(s):  
Escherichia Coli ◽  
Flow Cytometry ◽  
Growth Rates ◽  
Specific Growth ◽  
Bacterial Cells ◽  
Tetrazolium Chloride ◽  
E Coli ◽  
Escherichia Coli Cells ◽  
Cell Subpopulations ◽  
Specific Growth Rates

The physiological differences of individual cells of bacterial population may imply the existence of cell subpopulations with different sensitivity to chlorine, which may affect the efficiency of drinking water disinfection. The susceptibility of individual bacterial cells to chlorine was examined using flow cytometry. The inactivation of Escherichia coli cells by chlorine in the populations with specific growth rates of 0.2 and 0.9 h−1 was assessed using various viability indicators. Viability of bacterial cells was evaluated using membrane integrity propidium iodide (PI) dye, respiratory activity indicator of 5-cyano-2,3-ditolyl tetrazolium chloride (CTC) and membrane potential probe of DiBAC4(3). It was found that there were cell subpopulations of E. coli with different levels of susceptibility to chlorine. E. coli cell population with higher specific growth rate was more susceptible to chlorine. The CT values for inactivation of 99% of cells (CT99) in populations of E. coli with specific growth rates of 0.9 and 0.2 h−1 were 0.06 and 0.09 mg min l−1, respectively. Flow cytometry could be used to study the sensitivity of bacterial cells to the chemical agents.

Quantitative relationships for specific growth rates and macromolecular compositions of Mycobacterium tuberculosis, Streptomyces coelicolor A3(2) and Escherichia coli B/r: an integrative theoretical approach

Microbiology ◽  
2004 ◽  
Vol 150 (5) ◽  
pp. 1413-1426 ◽  
Author(s):  
Robert A. Cox
Keyword(s):  
Escherichia Coli ◽  
Growth Rate ◽  
Mycobacterium Tuberculosis ◽  
Growth Rates ◽  
Specific Growth ◽  
Streptomyces Coelicolor ◽  
Maximum Growth ◽  
Maximum Growth Rate ◽  
E Coli ◽  
Specific Growth Rates

Further understanding of the physiological states of Mycobacterium tuberculosis and other mycobacteria was sought through comparisons with the genomic properties and macromolecular compositions of Streptomyces coelicolor A3(2), grown at 30 °C, and Escherichia coli B/r, grown at 37 °C. A frame of reference was established based on quantitative relationships observed between specific growth rates (μ) of cells and their macromolecular compositions. The concept of a schematic cell based on transcription/translation coupling, average genes and average proteins was developed to provide an instantaneous view of macromolecular synthesis carried out by cells growing at their maximum rate. It was inferred that the ultra-fast growth of E. coli results from its ability to increase the average number of rRNA (rrn) operons per cell through polyploidy, thereby increasing its capacity for ribosome synthesis. The maximum growth rate of E. coli was deduced to be limited by the rate of uptake and consumption of nutrients providing energy. Three characteristic properties of S. coelicolor A3(2) growing optimally (μ=0·30 h−1) were identified. First, the rate of DNA replication was found to approach the rate reported for E. coli (μ=1·73 h−1); secondly, all rrn operons were calculated to be fully engaged in precursor-rRNA synthesis; thirdly, compared with E. coli, protein synthesis was found to depend on higher concentrations of ribosomes and lower concentrations of aminoacyl-tRNA and EF-Tu. An equation was derived for E. coli B/r relating μ to the number of rrn operons per genome. Values of μ=0·69 h−1 and μ=1·00 h−1 were obtained respectively for cells with one or two rrn operons per genome. Using the author's equation relating the number of rrn operons per genome to maximum growth rate, it is expected that M. tuberculosis with one rrn operon should be capable of growing much faster than it actually does. Therefore, it is suggested that the high number of insertion sequences in this species attenuates growth rate to still lower values.

scholarly journals Specific Growth Rate Determines the Sensitivity of Escherichia coli to Thermal, UVA, and Solar Disinfection

2006 ◽  
Vol 72 (4) ◽  
pp. 2586-2593 ◽  
Author(s):  
Michael Berney ◽  
Hans-Ulrich Weilenmann ◽  
Julian Ihssen ◽  
Claudio Bassin ◽  
Thomas Egli
Keyword(s):  
Escherichia Coli ◽  
Growth Rate ◽  
Specific Growth Rate ◽  
Growth Rates ◽  
Specific Growth ◽  
E Coli ◽  
Mild Heat ◽  
Uva Light ◽  
Specific Growth Rates ◽  
Slow Growing

ABSTRACT Knowledge about the sensitivity of the test organism is essential for the evaluation of any disinfection method. In this work we show that sensitivity of Escherichia coli MG1655 to three physical stresses (mild heat, UVA light, and sunlight) that are relevant in the disinfection of drinking water with solar radiation is determined by the specific growth rate of the culture. Batch- and chemostat-cultivated cells from cultures with similar specific growth rates showed similar stress sensitivities. Generally, fast-growing cells were more sensitive to the stresses than slow-growing cells. For example, slow-growing chemostat-cultivated cells (D = 0.08 h−1) and stationary-phase bacteria from batch culture that were exposed to mild heat had very similar T 90 (time until 90% of the population is inactivated) values (T 90, chemostat = 2.66 h; T 90, batch = 2.62 h), whereas T 90 for cells growing at a μ of 0.9 h−1 was 0.2 h. We present evidence that the stress sensitivity of E. coli is correlated with the intracellular level of the alternative sigma factor RpoS. This is also supported by the fact that E. coli rpoS mutant cells were more stress sensitive than the parent strain by factors of 4.9 (mild heat), 5.3 (UVA light), and 4.1 (sunlight). Furthermore, modeling of inactivation curves with GInaFiT revealed that the shape of inactivation curves changed depending on the specific growth rate. Inactivation curves of cells from fast-growing cultures (μ = 1.0 h−1) that were irradiated with UVA light showed a tailing effect, while for slow-growing cultures (μ = 0.3 h−1), inactivation curves with shoulders were obtained. Our findings emphasize the need for accurate reporting of specific growth rates and detailed culture conditions in disinfection studies to allow comparison of data from different studies and laboratories and sound interpretation of the data obtained.

scholarly journals RNase E Maintenance of Proper FtsZ/FtsA Ratio Required for Nonfilamentous Growth of Escherichia coli Cells but Not for Colony-Forming Ability

2006 ◽  
Vol 188 (14) ◽  
pp. 5145-5152 ◽  
Author(s):  
Masaru Tamura ◽  
Kangseok Lee ◽  
Christine A. Miller ◽  
Christopher J. Moore ◽  
Yukio Shirako ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Cell Division ◽  
Liquid Culture ◽  
Bacterial Cells ◽  
Rnase E ◽  
Null Mutant ◽  
E Coli ◽  
Escherichia Coli Cells ◽  
Solid Media ◽  
Rnase G

ABSTRACT Inactivation or deletion of the RNase E-encoding rne gene of Escherichia coli results in the growth of bacterial cells as filamentous chains in liquid culture (K. Goldblum and D. Apirion, J. Bacteriol. 146:128-132, 1981) and the loss of colony-forming ability (CFA) on solid media. RNase E dysfunction is also associated with abnormal processing of ftsQAZ transcripts (K. Cam, G. Rome, H. M. Krisch, and J.-P. Bouché, Nucleic Acids Res. 24:3065-3070, 1996), which encode proteins having a central role in septum formation during cell division. We show here that RNase E regulates the relative abundances of FtsZ and FtsA proteins and that RNase E depletion results in decreased FtsZ, increased FtsA, and consequently an altered FtsZ/FtsA ratio. However, while restoration of the level of FtsZ to normal in rne null mutant bacteria reverses the filamentation phenotype, it does not restore CFA. Conversely, overexpression of a related RNase, RNase G, in rne-deleted bacteria restores CFA, as previously reported, without affecting FtsZ abundance. Our results demonstrate that RNase E activity is required to maintain a proper cellular ratio of the FtsZ and FtsA proteins in E. coli but that FtsZ deficiency does not account for the nonviability of cells lacking RNase E.

scholarly journals Enhanced Production of δ-Guaiene, a Bicyclic Sesquiterpene Accumulated in Agarwood, by Coexpression of δ-Guaiene Synthase and Farnesyl Diphosphate Synthase Genes in Escherichia coli

2016 ◽  
Vol 11 (9) ◽  
pp. 1934578X1601100 ◽  
Author(s):  
Takahiro Kato ◽  
Jung-Bum Lee ◽  
Futoshi Taura ◽  
Fumiya Kurosaki
Keyword(s):  
Escherichia Coli ◽  
Recombinant Protein ◽  
Immunoblot Analysis ◽  
Farnesyl Diphosphate ◽  
Farnesyl Diphosphate Synthase ◽  
Transformed Cells ◽  
Bacterial Cells ◽  
E Coli ◽  
Enhanced Production ◽  
Escherichia Coli Cells

Two genes involved in δ-guaiene biosynthesis in Aquilaria microcarpa, δ-guaiene synthase (GS) and farnesyl diphosphate synthase (FPS), were overexpressed in Escherichia coli cells. Immunoblot analysis revealed that the concentration of GS-translated protein was rather low in the cells transformed by solely GS while appreciable accumulation of the recombinant protein was observed when GS was coexpressed with FPS GS-transformed cells liberated only a trace amount of δ-guaiene (0.004 μg/mL culture), however, the concentration of the compound elevated to 0.08 μg/mL culture in the cells transformed by GS plus FPS δ-Guaiene biosynthesis was markedly activated when E. coli cells coexpressing GS and FPS were incubated in enriched Terrific broth, and the content of the compound increased to approximately 0.6 μg/mL culture. These results suggest that coexpression of FPS and GS in E. coli is required for efficient 6-guaiene production in the bacterial cells, and the sesquiterpene-producing activity of the transformant is appreciably enhanced in the nutrients-enriched medium.

scholarly journals Stability of plasmid pBR322 within Escherichia coli cells

2021 ◽  
Vol 6 (1) ◽  
pp. 17-19
Author(s):  
Tahsin Tabassum ◽  
Tasmin Tabassum ◽  
Nafisa Tabassum ◽  
Syeda Muntaka Maniha ◽  
Rashed Noor
Keyword(s):  
Escherichia Coli ◽  
Drug Resistance ◽  
Heat Shock ◽  
Plasmid Stability ◽  
Bacterial Cells ◽  
Plasmid Pbr322 ◽  
E Coli ◽  
Replica Plating ◽  
Escherichia Coli Cells ◽  
Pbr322 Plasmid

nsertion of plasmids into the bacterial cells is of great significance especially in course of the transfer of drug resistance, virulence and other traits. Retention of plasmids within the host bacteria is therefore an important factor for bacterial homeostasis. Current study inferred the pBR322 plasmid stability within the Escherichia coli competent cells. The calcium chloride heat shock method was used for the transformation purpose. The plasmid retention phenomenon was assessed through the replica plating. The results positively showed the plasmid retention within E. coli.

Exogenous Histidine as a Co-factor which Exacerbates the Toxicity of Hydrogen Peroxide in Cultured Mammalian and Bacterial Cells

1991 ◽  
Vol 19 (1) ◽  
pp. 68-70
Author(s):  
Giorgio Brandi ◽  
Piero Sestili ◽  
Andrea Guidarelli ◽  
Giuditta Fiorella Schiavano ◽  
Amedeo Albano ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Amino Acids ◽  
Hydrogen Peroxide ◽  
Mammalian Cells ◽  
Culture Medium ◽  
Chinese Hamster ◽  
Bacterial Cells ◽  
E Coli ◽  
Escherichia Coli Cells ◽  
Casamino Acids

The killing of Escherichia coli cells by H2O2 is higher when exposure to the oxidant is performed in a complete culture medium, as compared to saline. Whereas MgSO4, CaCl2, thiamine or glucose, added separately or in combination with the saline, had no effect on the cytotoxic response to H2O2, the cytotoxicity appeared highly dependent upon the presence of the casamino acids in the incubation medium. One of these amino acids, histidine, was found to greatly augment the toxicity of H2O2 in E. coli. This effect of histidine was also observed in mammalian cells. In fact, both the cytoxicity and the DNA damage produced by H2O2 in Chinese hamster ovary (CHO) cells were significantly increased by this amino acid.

Heat Production and Growth Kinetics of E. coli K12 from Flow Calorimetric Measurements on Chemostat Cultures

1989 ◽  
Vol 44 (11-12) ◽  
pp. 1036-1048 ◽  
Author(s):  
H. P. Leiseifer
Keyword(s):  
Heat Production ◽  
Growth Rates ◽  
Specific Growth ◽  
Batch Cultures ◽  
E Coli ◽  
Chemostat Cultures ◽  
Basic Parameters ◽  
Specific Growth Rates ◽  
The Relationship ◽  
Kinetics Of

The heat production of E. coli K12 growing aerobically in glucose limited chemostat cultures is determined in the range of specific growth rates μ ( = dilution rates D) from 0,058 h-1 to 0.852 h-1 for two different glucose concentrations Se in the instream of the chemostat. namely Se1=0.3182 g·1-1 and Se2 = 0.6364 g·1-1. Heat production Q and biomass production P per unit of culture volume show well correlated patterns for Se1 and Se2. For Se1 the highest value Q actually measured is 443-10-3 W·1-1 at D = 0.74 h-1 with P = 0.068 g·1-1·h-1 and for Se2 593·10-3 W·1-1 at D = 0.497 h-1 with P = 0.108 g·1-1·h-1. Heat production QB per unit of biomass appears to be independent of Se at least up to D - 0.5 h-1.At higher D there is strong indication that QB possesses a real maximum. The highest value of QB actually measured is 4.8 W·g-1 at D = 0.74 h-1. For Se1 and Se2 there were significantly higher specific growth rates verified in chemostat culture than μmaxBatch= 0.717 h-1 which is the maximum specific growth rate in comparable, unlimited batch cultures. The real maximum of QB is estimated to be in the vicinity of μmaxBatch. This suggests the hypothesis of a maximum principle for the growth in batch culture. For Se1 a closed analytical expression is derived for the relationship between μ and the substrate concentration S. μ[S] features a S-shaped characteristic with μmaxChemostat= 0.905 h-1; 1/2 μmaxChemostat is reached at S = 2.85·10-3 g·1-1. Three basic parameters which characterize the overall metabolism of the cells, namely the heat released per unit of substrate consumed, (Qs, the effective yield of biomass, Yeff, and μmaxChemostat are identified to depend on Se.

Insights into the persistence and phenotypic effects of the endogenous and cryptic plasmid pMF1 in its host strain Myxococcus fulvus 124B02

2020 ◽  
Vol 96 (3) ◽  
Author(s):  
Xiao-jing Chen ◽  
Zheng Zhang ◽  
Ya-jie Li ◽  
Li Zhuo ◽  
Duo-hong Sheng ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Bacterial Cells ◽  
Fruiting Bodies ◽  
Long Term Effects ◽  
Laboratory Evolution ◽  
E Coli ◽  
Escherichia Coli Cells ◽  
The Social ◽  
Cryptic Plasmids

ABSTRACT Many endogenous plasmids carry no noticeable benefits for their bacterial hosts, and the persistence of these ‘cryptic plasmids’ and their functional impacts are mostly unclear. In this study, we investigated these uncertainties using the social bacterium Myxococcus fulvus 124B02 and its endogenous plasmid pMF1. pMF1 possesses diverse genes that originated from myxobacteria, suggesting a longstanding co-existence of the plasmid with various myxobacterial species. The curing of pMF1 from 124B02 had almost no phenotypic effects on the host. Laboratory evolution experiments showed that the 124B02 strain retained pMF1 when subcultured on dead Escherichia coli cells but lost pMF1 when subcultured on living E. coli cells or on casitone medium; these results indicated that the persistence of pMF1 in 124B02 was environment-dependent. Curing pMF1 caused the mutant to lose the ability to predate and develop fruiting bodies more quickly than the pMF1-containing strain after they were subcultured on dead E. coli cells, which indicated that the presence of pMF1 in M. fulvus 124B02 has some long-term effects on its host. The results provide some new insights into the persistence and impacts of cryptic plasmids in their natural bacterial cells.

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