Enhanced Astaxanthin Production in Escherichia coli via Morphology and Oxidative Stress Engineering

2019 ◽  
Vol 67 (42) ◽  
pp. 11703-11709 ◽  
Author(s):  
Qian Lu ◽  
Jian-Zhong Liu
Keyword(s):  
Oxidative Stress ◽  
Escherichia Coli ◽  
Astaxanthin Production ◽  
Stress Engineering ◽  
And Oxidative Stress

scholarly journals Escherichia coli mazEF-Mediated Cell Death Is Triggered by Various Stressful Conditions

2004 ◽  
Vol 186 (11) ◽  
pp. 3663-3669 ◽  
Author(s):  
Ronen Hazan ◽  
Boaz Sat ◽  
Hanna Engelberg-Kulka
Keyword(s):  
Oxidative Stress ◽  
Escherichia Coli ◽  
Dna Damage ◽  
Cell Death ◽  
High Temperatures ◽  
And Oxidative Stress ◽  
Logarithmic Growth

ABSTRACT mazEF is an Escherichia coli suicide module specific for a stable toxin and a labile antitoxin. Inhibiting mazEF expression appeared to activate the module to cause cell death. Here we show that several stressful conditions, including high temperatures, DNA damage, and oxidative stress, also induce mazEF-mediated cell death. We also show that this process takes place only during logarithmic growth and requires an intact relA gene.

scholarly journals Bacterial Hemoglobins and Flavohemoglobins for Alleviation of Nitrosative Stress in Escherichia coli

2002 ◽  
Vol 68 (10) ◽  
pp. 4835-4840 ◽  
Author(s):  
Alexander D. Frey ◽  
Judith Farrés ◽  
Christian J. T. Bollinger ◽  
Pauli T. Kallio
Keyword(s):  
Oxidative Stress ◽  
Escherichia Coli ◽  
Wild Type Strain ◽  
Nitrosative Stress ◽  
Deinococcus Radiodurans ◽  
E Coli ◽  
Oxidative Challenge ◽  
Taxonomic Groups ◽  
And Oxidative Stress

ABSTRACT Escherichia coli MG1655 cells expressing novel bacterial hemoglobin and flavohemoglobin genes from a medium-copy-number plasmid were grown in shake flask cultures under nitrosative and oxidative stress. E. coli cells expressing these proteins display enhanced resistance against the NO· releaser sodium nitroprusside (SNP) relative to that of the control strain bearing the parental plasmid. Expression of bacterial hemoglobins originating from Campylobacter jejuni (CHb) and Vitreoscilla sp. (VHb) conferred resistance on SNP-challenged cells. In addition, it has been shown that NO· detoxification is also a common feature of flavohemoglobins originating from different taxonomic groups and can be transferred to a heterologous host. These observations have been confirmed in a specific in vitro NO· consumption assay. Protein extracts isolated from E. coli strains overexpressing flavohemoglobins consumed authentic NO· more readily than protein extracts from the wild-type strain. Oxidative challenge to the cells evoked nonuniform responses from the various cell cultures. Improved oxidative-stress-sustaining properties had also been observed when the flavohemoglobins from E. coli, Klebsiella pneumoniae, Deinococcus radiodurans, and Pseudomonas aeruginosa were expressed in E. coli.

scholarly journals Genome-Wide Transcriptional Responses of Escherichia coli K-12 to Continuous Osmotic and Heat Stresses

2008 ◽  
Vol 190 (10) ◽  
pp. 3712-3720 ◽  
Author(s):  
Thusitha S. Gunasekera ◽  
Laszlo N. Csonka ◽  
Oleg Paliy
Keyword(s):  
Oxidative Stress ◽  
Escherichia Coli ◽  
High Temperature ◽  
Osmotic Stress ◽  
Stress Responses ◽  
Transcriptional Responses ◽  
High Osmolarity ◽  
Genome Wide ◽  
K 12 ◽  
And Oxidative Stress

ABSTRACT Osmotic stress is known to increase the thermotolerance and oxidative-stress resistance of bacteria by a mechanism that is not adequately understood. We probed the cross-regulation of continuous osmotic and heat stress responses by characterizing the effects of external osmolarity (0.3 M versus 0.0 M NaCl) and temperature (43°C versus 30°C) on the transcriptome of Escherichia coli K-12. Our most important discovery was that a number of genes in the SoxRS and OxyR oxidative-stress regulons were up-regulated by high osmolarity, high temperature, or a combination of both stresses. This result can explain the previously noted cross-protection of osmotic stress against oxidative and heat stresses. Most of the genes shown in previous studies to be induced during the early phase of adaptation to hyperosmotic shock were found to be also overexpressed under continuous osmotic stress. However, there was a poorer overlap between the heat shock genes that are induced transiently after high temperature shifts and the genes that we found to be chronically up-regulated at 43°C. Supplementation of the high-osmolarity medium with the osmoprotectant glycine betaine, which reduces the cytoplasmic K+ pool, did not lead to a universal reduction in the expression of osmotically induced genes. This finding does not support the hypothesis that K+ is the central osmoregulatory signal in Enterobacteriaceae.

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