scholarly journals Manipulations of AMP Metabolic Genes Increase Growth Rate and Cold Tolerance in Escherichia coli: Implications for Psychrophilic Evolution

2011 ◽  
Vol 28 (7) ◽  
pp. 2139-2145 ◽  
Author(s):  
B. R. Parry ◽  
D. H. Shain
Keyword(s):  
Escherichia Coli ◽  
Growth Rate ◽  
Cold Tolerance ◽  
Increase Growth Rate ◽  
Metabolic Genes

scholarly journals Optimized expression of Hfq protein increases Escherichia coli growth

2021 ◽  
Vol 15 (1) ◽  
Author(s):  
Phuong N. L. VO ◽  
Hyang-Mi LEE ◽  
Jun REN ◽  
Dokyun NA
Keyword(s):  
Escherichia Coli ◽  
Growth Rate ◽  
Stress Responses ◽  
Bacterial Species ◽  
Expression Level ◽  
Rna Seq ◽  
E Coli ◽  
Network Analyses ◽  
Metabolic Genes ◽  
Cell Densities

AbstractEscherichia coli is a widely used platform for metabolic engineering due to its fast growth and well-established engineering techniques. However, there has been a demand for faster-growing E. coli for higher production of desired substances. Here, to increase the growth of E. coli cells, we optimized the expression level of Hfq protein, which plays an essential role in stress responses. Six variants of the hfq gene with a different ribosome binding site sequence and thereby a different expression level were constructed. When the Hfq expression level was optimized in DH5α, its growth rate was increased by 12.1% and its cell density was also increased by 4.5%. RNA-seq and network analyses revealed the upregulation of stress response genes and metabolic genes, which increases the tolerance against pH changes. When the same strategy was applied to five other E. coli strains (BL21 (DE3), JM109, TOP10, W3110, and MG1655), all their growth rates were increased by 18–94% but not all their densities were increased (− 12 − + 32%). In conclusion, the Hfq expression optimization can increase cell growth rate and probably their cell densities as well. Since the hfq gene is highly conserved across bacterial species, the same strategy could be applied to other bacterial species to construct faster-growing strains.

scholarly journals Transcriptome analysis of Escherichia coli K1 after therapy with hesperidin conjugated with silver nanoparticles

2021 ◽  
Vol 21 (1) ◽  
Author(s):  
Abdulkader Masri ◽  
Naveed Ahmed Khan ◽  
Muhammad Zarul Hanifah Md Zoqratt ◽  
Qasim Ayub ◽  
Ayaz Anwar ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Silver Nanoparticles ◽  
Minimum Inhibitory Concentration ◽  
Inhibitory Concentration ◽  
Neonatal Meningitis ◽  
E Coli ◽  
Drug Candidates ◽  
Metabolic Genes ◽  
Genetic Mechanisms ◽  
Cell Stress Response

Abstract Backgrounds Escherichia coli K1 causes neonatal meningitis. Transcriptome studies are indispensable to comprehend the pathology and biology of these bacteria. Recently, we showed that nanoparticles loaded with Hesperidin are potential novel antibacterial agents against E. coli K1. Here, bacteria were treated with and without Hesperidin conjugated with silver nanoparticles, and silver alone, and 50% minimum inhibitory concentration was determined. Differential gene expression analysis using RNA-seq, was performed using Degust software and a set of genes involved in cell stress response and metabolism were selected for the study. Results 50% minimum inhibitory concentration with silver-conjugated Hesperidin was achieved with 0.5 μg/ml of Hesperidin conjugated with silver nanoparticles at 1 h. Differential genetic analysis revealed the expression of 122 genes (≥ 2-log FC, P< 0.01) in both E. coli K1 treated with Hesperidin conjugated silver nanoparticles and E. coli K1 treated with silver alone, compared to untreated E. coli K1. Of note, the expression levels of cation efflux genes (cusA and copA) and translocation of ions, across the membrane genes (rsxB) were found to increase 2.6, 3.1, and 3.3- log FC, respectively. Significant regulation was observed for metabolic genes and several genes involved in the coordination of flagella. Conclusions The antibacterial mechanism of nanoparticles maybe due to disruption of the cell membrane, oxidative stress, and metabolism in E. coli K1. Further studies will lead to a better understanding of the genetic mechanisms underlying treatment with nanoparticles and identification of much needed novel antimicrobial drug candidates.

scholarly journals In vitro culture as an aid to conservation of indigenous ferns: Diplazium proliferum

2015 ◽  
Vol 6 (1) ◽  
Author(s):  
Zubeir M. Golamaully ◽  
Vishwakalyan Bhoyroo ◽  
Nadeem Nazurally ◽  
Vineshwar Gopal
Keyword(s):  
Growth Rate ◽  
In Vitro Culture ◽  
Mercuric Chloride ◽  
Rare Species ◽  
Vascular Plants ◽  
Culture Media ◽  
Fungal Contamination ◽  
Increase Growth Rate ◽  
Growing Population

With the ever growing population and economic needs of Mauritius, the flora of Mauritius has never been in more danger and one group of vascular plants is even more in peril; ferns.<em> Diplazium proliferum</em> is indigenous to the Mascarene region and is considered as a rare species in Mauritius. The need to develop a tested <em>in vitro</em> propagation protocol is a must to protect the biodiversity of Mauritius. This experiment was geared towards the establishment of a proper sterilization technique and the effect of 6-benzylaminopurine (BAP) and light on <em>in vitro</em> culture of this fern. Sterilization with 0.05% Mercuric chloride was effective to eliminate fungal contamination and allow germination of spores. Culture media supplemented with BAP did not significantly increase growth rate of both gametophytes and sporophytes of<em> D. proliferum</em>. Present results suggest efficient sterilization methods to be a crucial stage for successful<em> in vitro r</em>egeneration of ferns. The established protocol will be used as an optimized baseline protocol for the propagation of other indigenous ferns.

scholarly journals Role of growth rate on the orientational alignment of Escherichia coli in a slit

2017 ◽  
Vol 4 (6) ◽  
pp. 170463 ◽  
Author(s):  
Julian Sheats ◽  
Bianca Sclavi ◽  
Marco Cosentino Lagomarsino ◽  
Pietro Cicuta ◽  
Kevin D. Dorfman
Keyword(s):  
Escherichia Coli ◽  
Growth Rate ◽  
Aspect Ratio ◽  
Density Fluctuations ◽  
Global Alignment ◽  
Similar Amount ◽  
Cell Area ◽  
Nematic Ordering ◽  
Side Walls

We present experimental data on the nematic alignment of Escherichia coli bacteria confined in a slit, with an emphasis on the effect of growth rate and corresponding changes in cell aspect ratio. Global alignment with the channel walls arises from the combination of local nematic ordering of nearby cells, induced by cell division and the elongated shape of the cells, and the preferential orientation of cells proximate to the side walls of the slit. Decreasing the growth rate leads to a decrease in alignment with the walls, which is attributed primarily to effects of changing cell aspect ratio rather than changes in the variance in cell area. Decreasing confinement also reduces the degree of alignment by a similar amount as a decrease in the growth rate, but the distribution of the degree of alignment differs. The onset of alignment with the channel walls is coincident with the slits reaching their steady-state occupancy and connected to the re-orientation of locally aligned regions with respect to the walls during density fluctuations.

Growth-rate dependent regulation of mRNA stability in Escherichia coli

Nature ◽  
1984 ◽  
Vol 312 (5989) ◽  
pp. 75-77 ◽  
Author(s):  
G. Nilsson ◽  
J. G. Belasco ◽  
S. N. Cohen ◽  
A. von Gabain
Keyword(s):  
Escherichia Coli ◽  
Growth Rate ◽  
Mrna Stability ◽  
Rate Dependent

scholarly journals Escherichia colipopulations adapt to complex, unpredictable fluctuations without any trade-offs across environments

2016 ◽  
Author(s):  
Shraddha Karve ◽  
Devika Bhave ◽  
Dhanashri Nevgi ◽  
Sutirth Dey
Keyword(s):  
Escherichia Coli ◽  
Growth Rate ◽  
Growth Rates ◽  
Complex Environments ◽  
Multiple Stresses ◽  
Trade Off ◽  
Trade Offs ◽  
Fluctuating Environments ◽  
Laboratory Populations ◽  
Lower Variation

AbstractIn nature, organisms are simultaneously exposed to multiple stresses (i.e. complex environments) that often fluctuate unpredictably. While both these factors have been studied in isolation, the interaction of the two remains poorly explored. To address this issue, we selected laboratory populations ofEscherichia coliunder complex (i.e. stressful combinations of pH, H2O2and NaCl) unpredictably fluctuating environments for ~900 generations. We compared the growth rates and the corresponding trade-off patterns of these populations to those that were selected under constant values of the component stresses (i.e. pH, H2O2and NaCl) for the same duration. The fluctuation-selected populations had greater mean growth rate and lower variation for growth rate over all the selection environments experienced. However, while the populations selected under constant stresses experienced severe tradeoffs in many of the environments other than those in which they were selected, the fluctuation-selected populations could by-pass the across-environment trade-offs completely. Interestingly, trade-offs were found between growth rates and carrying capacities. The results suggest that complexity and fluctuations can strongly affect the underlying trade-off structure in evolving populations.

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