scholarly journals AnEscherichia colinitrogen starvation response is important for mutualistic coexistence withRhodopseudomonas palustris

2018 ◽  
Author(s):  
Alexandra L. McCully ◽  
Megan G. Behringer ◽  
Jennifer R. Gliessman ◽  
Evgeny V. Pilipenko ◽  
Jeffrey L. Mazny ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Nitrogen Starvation ◽  
Physiological State ◽  
Rhodopseudomonas Palustris ◽  
Genetically Engineered ◽  
Individual Species ◽  
Starvation Response ◽  
E Coli ◽  
Protein Levels ◽  
Stable Coexistence

AbstractMicrobial mutualistic cross-feeding interactions are ubiquitous and can drive important community functions. Engaging in cross-feeding undoubtedly affects the physiology and metabolism of individual species involved. However, the nature in which an individual’s physiology is influenced by cross-feeding and the importance of those physiological changes for the mutualism have received little attention. We previously developed a genetically tractable coculture to study bacterial mutualisms. The coculture consists of fermentativeEscherichia coliand phototrophicRhodopseudomonas palustris. In this coculture, E. coli anaerobically ferments sugars into excreted organic acids as a carbon source for R. palustris. In return, a genetically-engineered R. palustris constitutively converts N2into NH4+, providingE. coliwith essential nitrogen. Using RNA-seq and proteomics, we identified transcript and protein levels that differ in each partner when grown in coculture versus monoculture. When in coculture withR. palustris, E. coligene-expression changes resembled a nitrogen starvation response under the control of the transcriptional regulator NtrC. By genetically disruptingE. coliNtrC, we determined that a nitrogen starvation response is important for a stable coexistence, especially at lowR. palustrisNH4+excretion levels. Destabilization of the nitrogen starvation regulatory network resulted in variable growth trends and in some cases, extinction. Our results highlight that alternative physiological states can be important for survival within cooperative cross-feeding relationships.ImportanceMutualistic cross-feeding between microbes within multispecies communities is widespread. Studying how mutualistic interactions influence the physiology of each species involved is important for understanding how mutualisms function and persist in both natural and applied settings. Using a bacterial mutualism consisting ofRhodopseudomonas palustrisandEscherichia coligrowing cooperatively through bidirectional nutrient exchange, we determined that anE. colinitrogen starvation response is important for maintaining a stable coexistence. The lack of anE. colinitrogen starvation response ultimately destabilized the mutualism and, in some cases, led to community collapse after serial transfers. Our findings thus inform on the potential necessity of an alternative physiological state for mutualistic coexistence with another species compared to the physiology of species grown in isolation.

scholarly journals AnEscherichia coliNitrogen Starvation Response Is Important for Mutualistic Coexistence withRhodopseudomonas palustris

2018 ◽  
Vol 84 (14) ◽  
Author(s):  
Alexandra L. McCully ◽  
Megan G. Behringer ◽  
Jennifer R. Gliessman ◽  
Evgeny V. Pilipenko ◽  
Jeffrey L. Mazny ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Nitrogen Starvation ◽  
Physiological State ◽  
Rhodopseudomonas Palustris ◽  
Genetically Engineered ◽  
Individual Species ◽  
Starvation Response ◽  
Content Type ◽  
E Coli ◽  
Stable Coexistence

ABSTRACTMicrobial mutualistic cross-feeding interactions are ubiquitous and can drive important community functions. Engaging in cross-feeding undoubtedly affects the physiology and metabolism of individual species involved. However, the nature in which an individual species' physiology is influenced by cross-feeding and the importance of those physiological changes for the mutualism have received little attention. We previously developed a genetically tractable coculture to study bacterial mutualisms. The coculture consists of fermentativeEscherichia coliand phototrophicRhodopseudomonas palustris. In this coculture,E. colianaerobically ferments sugars into excreted organic acids as a carbon source forR. palustris. In return, a genetically engineeredR. palustrisstrain constitutively converts N2into NH4+, providingE. coliwith essential nitrogen. Using transcriptome sequencing (RNA-seq) and proteomics, we identified transcript and protein levels that differ in each partner when grown in coculture versus monoculture. When in coculture withR. palustris,E. coligene expression changes resembled a nitrogen starvation response under the control of the transcriptional regulator NtrC. By genetically disruptingE. coliNtrC, we determined that a nitrogen starvation response is important for a stable coexistence, especially at lowR. palustrisNH4+excretion levels. Destabilization of the nitrogen starvation regulatory network resulted in variable growth trends and, in some cases, extinction. Our results highlight that alternative physiological states can be important for survival within cooperative cross-feeding relationships.IMPORTANCEMutualistic cross-feeding between microbes within multispecies communities is widespread. Studying how mutualistic interactions influence the physiology of each species involved is important for understanding how mutualisms function and persist in both natural and applied settings. Using a bacterial mutualism consisting ofRhodopseudomonas palustrisandEscherichia coligrowing cooperatively through bidirectional nutrient exchange, we determined that anE. colinitrogen starvation response is important for maintaining a stable coexistence. The lack of anE. colinitrogen starvation response ultimately destabilized the mutualism and, in some cases, led to community collapse after serial transfers. Our findings thus inform on the potential necessity of an alternative physiological state for mutualistic coexistence with another species compared to the physiology of species grown in isolation.

scholarly journals Fermentative Escherichia coli makes a substantial contribution to H2 production in coculture with phototrophic Rhodopseudomonas palustris

2019 ◽  
Vol 366 (14) ◽  
Author(s):  
Amee A Sangani ◽  
Alexandra L McCully ◽  
Breah LaSarre ◽  
James B McKinlay
Keyword(s):  
Escherichia Coli ◽  
Rhodopseudomonas Palustris ◽  
H2 Production ◽  
Substantial Contribution ◽  
Individual Species ◽  
Ammonium Excretion ◽  
E Coli ◽  
Carbon And Nitrogen ◽  
Relative Contribution ◽  
Mutualistic Relationship

ABSTRACT Individual species within microbial communities can combine their attributes to produce services that benefit society, such as the transformation of renewable resources into valuable chemicals. Under defined genetic and environmental conditions, fermentative Escherichia coli and phototrophic Rhodopseudomonas palustris exchange essential carbon and nitrogen, respectively, to establish a mutualistic relationship. In this relationship, each species produces H2 biofuel as a byproduct of its metabolism. However, the extent to which each species contributes to H2 production and the factors that influence their relative contributions were previously unknown. By comparing H2 yields in cocultures pairing R. palustris with either wild-type E. coli or a formate hydrogenlyase mutant that is incapable of H2 production, we determined the relative contribution of each species to total H2 production. Our results indicate that E. coli contributes between 32 and 86% of the H2 produced in coculture depending on the level of ammonium excreted by the R. palustris partner. The level of ammonium excretion influenced the time over which E. coliwas exposed to formate, the types of E. colifermentation products available to R. palustris, and the pH of the medium, all of which affected the contribution of each species to H2 production.

Biodecomposition of Phenanthrene and Pyrene by a Genetically Engineered Escherichia coli

2020 ◽  
Vol 14 (2) ◽  
pp. 121-133 ◽  
Author(s):  
Maryam Ahankoub ◽  
Gashtasb Mardani ◽  
Payam Ghasemi-Dehkordi ◽  
Ameneh Mehri-Ghahfarrokhi ◽  
Abbas Doosti ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
High Performance ◽  
Human Cancer ◽  
Genetically Engineered ◽  
Hazardous Substances ◽  
E Coli ◽  
Spiked Soil ◽  
Engineered Escherichia Coli ◽  
Genetically Manipulated ◽  
Hplc Measurement

Background: Genetically engineered microorganisms (GEMs) can be used for bioremediation of the biological pollutants into nonhazardous or less-hazardous substances, at lower cost. Polycyclic aromatic hydrocarbons (PAHs) are one of these contaminants that associated with a risk of human cancer development. Genetically engineered E. coli that encoded catechol 2,3- dioxygenase (C230) was created and investigated its ability to biodecomposition of phenanthrene and pyrene in spiked soil using high-performance liquid chromatography (HPLC) measurement. We revised patents documents relating to the use of GEMs for bioremediation. This approach have already been done in others studies although using other genes codifying for same catechol degradation approach. Objective: In this study, we investigated biodecomposition of phenanthrene and pyrene by a genetically engineered Escherichia coli. Methods: Briefly, following the cloning of C230 gene (nahH) into pUC18 vector and transformation into E. coli Top10F, the complementary tests, including catalase, oxidase and PCR were used as on isolated bacteria from spiked soil. Results: The results of HPLC measurement showed that in spiked soil containing engineered E. coli, biodegradation of phenanthrene and pyrene comparing to autoclaved soil that inoculated by wild type of E. coli and normal soil group with natural microbial flora, were statistically significant (p<0.05). Moreover, catalase test was positive while the oxidase tests were negative. Conclusion: These findings indicated that genetically manipulated E. coli can provide an effective clean-up process on PAH compounds and it is useful for bioremediation of environmental pollution with petrochemical products.

scholarly journals Escherichia coli as a genetic tool

1985 ◽  
Vol 95 (3) ◽  
pp. 611-618
Author(s):  
Naomi Datta
Keyword(s):  
Escherichia Coli ◽  
Academic Research ◽  
Genetically Engineered ◽  
Cloning And Expression ◽  
Biological Research ◽  
New Techniques ◽  
E Coli ◽  
Genetic Tool ◽  
The Past ◽  
Made In

SUMMARYThe study of Escherichia coli and its plasmids and bacteriophages has provided a vast body of genetical information, much of it relevant to the whole of biology. This was true even before the development of the new techniques, for cloning and analysing DNA, that have revolutionized biological research during the past decade. Thousands of millions of dollars are now invested in industrial uses of these techniques, which all depend on discoveries made in the course of academic research on E. coli. Much of the background of knowledge necessary for the cloning and expression of genetically engineered information, as well as the techniques themselves, came from work with this organism.

scholarly journals Enhanced nutrient uptake is sufficient to drive emergent cross-feeding between bacteria in a synthetic community

2019 ◽  
Author(s):  
Ryan K Fritts ◽  
Jordan T Bird ◽  
Megan G Behringer ◽  
Anna Lipzen ◽  
Joel Martin ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Nutrient Uptake ◽  
Rhodopseudomonas Palustris ◽  
Biogeochemical Cycles ◽  
Wild Type ◽  
Fermentation Products ◽  
E Coli ◽  
Constitutive Activation ◽  
Host Health ◽  
Nitrogen Scavenging

ABSTRACTInteractive microbial communities are ubiquitous, influencing biogeochemical cycles and host health. One widespread interaction is nutrient exchange, or cross-feeding, wherein metabolites are transferred between microbes. Some cross-fed metabolites, such as vitamins, amino acids, and ammonium (NH4+), are communally valuable and impose a cost on the producer. The mechanisms that enforce cross-feeding of communally valuable metabolites are not fully understood. Previously we engineered mutualistic cross-feeding between N2-fixing Rhodopseudomonas palustris and fermentative Escherichia coli. Engineered R. palustris excreted essential nitrogen as NH4+ to E. coli while E. coli excreted essential carbon as fermentation products to R. palustris. Here, we enriched for nascent cross-feeding in cocultures with wild-type R. palustris, not known to excrete NH4+. Emergent NH4+ cross-feeding was driven by adaptation of E. coli alone. A missense mutation in E. coli NtrC, a regulator of nitrogen scavenging, resulted in constitutive activation of an NH4+ transporter. This activity likely allowed E. coli to subsist on the small amount of leaked NH4+ and better reciprocate through elevated excretion of organic acids from a larger E. coli population. Our results indicate that enhanced nutrient uptake by recipients, rather than increased excretion by producers, is an underappreciated yet possibly prevalent mechanism by which cross-feeding can emerge.

Optimizing a production strategy for a nonspecific nuclease from Yersinia enterocolitica subsp. palearctica in genetically engineered Escherichia coli

2019 ◽  
Vol 366 (24) ◽  
Author(s):  
Yan Ge ◽  
Senlin Guo ◽  
Tao Liu ◽  
Chen Zhao ◽  
Duanhua Li ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Yersinia Enterocolitica ◽  
Inclusion Bodies ◽  
Genetically Engineered ◽  
Biological Research ◽  
Dilution Method ◽  
E Coli ◽  
Protein Renaturation ◽  
Engineered Escherichia Coli ◽  
Pharmaceutical Production

ABSTRACT A nuclease from Yersinia enterocolitica subsp. palearctica (Nucyep) is a newly found thermostable nonspecific nuclease. The heat-resisting ability of this nuclease would be extremely useful in biological research or pharmaceutical production. However, the application of this nuclease is limited because of its poor yield. This research aimed to improve Nucyep productivity by producing a novel genetically engineered Escherichia coli and optimizing the production procedures. After 4 h of induction by lactose, the new genetically engineered E. coli can express a substantial amount of Nucyep in the form of inclusion bodies. The yield was approximately 0.3 g of inclusion bodies in 1 g of bacterial pellets. The inclusion bodies were extracted by sonication and solubilized in an 8 M urea buffer. Protein renaturation was successfully achieved by dilution method. Pure enzyme was obtained after subjecting the protein solution to anion exchange. The Nucyep showed its nonspecific and heat resistant properties as previously reported (Boissinot et  al. 2016). Through a quantification method, its activity was determined to be 1.3 × 10 6 Kunitz units (K.U.)/mg. These results can serve as a reference for increasing Nucyep production.

scholarly journals OmpC regulation differs between ST131 and non-ST131 Escherichia coli clinical isolates and involves differential expression of the small RNA MicC

2020 ◽  
Vol 75 (5) ◽  
pp. 1151-1158
Author(s):  
Corey S Suelter ◽  
Nancy D Hanson
Keyword(s):  
Escherichia Coli ◽  
Half Life ◽  
Selective Advantage ◽  
Resistance Mechanisms ◽  
Northern Blotting ◽  
Rt Pcr ◽  
E Coli ◽  
Protein Levels ◽  
Porin Proteins ◽  
Mrna Half Life

Abstract Background Virulence genes and the expression of resistance mechanisms undoubtedly play a role in the successful spread of the pandemic clone Escherichia coli ST131. Porin down-regulation is a chromosomal mechanism associated with antibiotic resistance. Translation of porin proteins can be impacted by modifications in mRNA half-life and the interaction among small RNAs (sRNAs), the porin transcript and the sRNA chaperone Hfq. Modifications in the translatability of porin proteins could impact the fitness and therefore the success of E. coli ST131 isolates in the presence of antibiotic. Objectives To identify differences in the translatability of OmpC and OmpF porins for different STs of E. coli by comparing steady-state RNA levels, mRNA half-life, regulatory sRNA expression and protein production. Methods RNA expression was evaluated using real-time RT–PCR and OmpC mRNA half-life by northern blotting. OmpC, OmpF and Hfq protein levels were evaluated by immunoblotting. Results Differences between ST131 and non-ST131 isolates included: (i) the level of OmpC RNA and protein produced with mRNA expression higher for ST131 but OmpC protein levels lower compared with non-ST131 isolates; (ii) OmpC mRNA half-life (21–30 min for ST131 isolates compared with &lt;2–23 min for non-ST131 isolates); and (iii) levels of the sRNA MicC (2- to 120-fold for ST131 isolates compared with −4- to 70-fold for non-ST131 isolates). Conclusions Mechanisms involved in the translatability of porin proteins differed among different STs of E. coli. These differences could provide a selective advantage to ST131 E. coli when confronted with an antibiotic-rich environment.

scholarly journals A study of SeqA subcellular localization in Escherichia coli using photo-activated localization microscopy

2015 ◽  
Vol 184 ◽  
pp. 425-450 ◽  
Author(s):  
Jacek T. Mika ◽  
Aster Vanhecke ◽  
Peter Dedecker ◽  
Toon Swings ◽  
Jeroen Vangindertael ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Cell Cycle ◽  
Bacterial Genome ◽  
Genetically Engineered ◽  
Replication Initiation ◽  
Cell Protein ◽  
Experimental Conditions ◽  
Localization Microscopy ◽  
E Coli ◽  
Copy Numbers

Escherichia coli (E. coli) cells replicate their genome once per cell cycle to pass on genetic information to the daughter cells. The SeqA protein binds the origin of replication, oriC, after DNA replication initiation and sequesters it from new initiations in order to prevent overinitiation. Conventional fluorescence microscopy studies of SeqA localization in bacterial cells have shown that the protein is localized to discrete foci. In this study we have used photo-activated localization microscopy (PALM) to determine the localization of SeqA molecules, tagged with fluorescent proteins, with a localization precision of 20–30 nm with the aim to visualize the SeqA subcellular structures in more detail than previously possible. SeqA–PAmCherry was imaged in wild type E. coli, expressed from plasmid or genetically engineered into the bacterial genome, replacing the native seqA gene. Unsynchronized cells as well as cells with a synchronized cell cycle were imaged at various time points, in order to investigate the evolution of SeqA localization during the cell cycle. We found that SeqA indeed localized into discrete foci but these were not the only subcellular localizations of the protein. A significant amount of SeqA–PAmCherry molecules was localized outside the foci and in a fraction of cells we saw patterns indicating localization at the membrane. Using quantitative PALM, we counted protein copy numbers per cell, protein copy numbers per focus, the numbers of foci per cell and the sizes of the SeqA clusters. The data showed broad cell-to-cell variation and we did not observe a correlation between SeqA–PAmCherry protein numbers and the cell cycle under the experimental conditions of this study. The numbers of SeqA–PAmCherry molecules per focus as well as the foci sizes also showed broad distributions indicating that the foci are likely not characterized by a fixed number of molecules. We also imaged an E. coli strain devoid of the dam methylase (Δdam) and observed that SeqA–PAmCherry no longer formed foci, and was dispersed throughout the cell and localized to the plasma membrane more readily. We discuss our results in the context of the limitations of the technique.

scholarly journals P1 Trisaccharide (Galα1,4Galβ1,4GlcNAc) Synthesis by Enzyme Glycosylation Reactions Using Recombinant Escherichia coli

2003 ◽  
Vol 69 (4) ◽  
pp. 2110-2115 ◽  
Author(s):  
Ziye Liu ◽  
Yuquan Lu ◽  
Jianbo Zhang ◽  
Keith Pardee ◽  
Peng George Wang
Keyword(s):  
Escherichia Coli ◽  
Sucrose Synthase ◽  
Pathogenic Bacteria ◽  
Enzymatic Reaction ◽  
Genetically Engineered ◽  
Reaction Volume ◽  
Recombinant Bacteria ◽  
Preparative Scale ◽  
E Coli ◽  
Oligosaccharide Moiety

ABSTRACT The frequency of Escherichia coli infection has lead to concerns over pathogenic bacteria in our food supply and a demand for therapeutics. Glycolipids on gut cells serve as receptors for the Shiga-like toxin produced by E. coli. Oligosaccharide moiety analogues of these glycolipids can compete with receptors for the toxin, thus acting as antibacterials. An enzymatic synthesis of the P1 trisaccharide (Galα1,4Galβ1,4GlcNAc), one of the oligosaccharide analogues, was assessed in this study. In the proposed synthetic pathway, UDP-glucose was generated from sucrose with an Anabaena sp. sucrose synthase and then converted with an E. coli UDP-glucose 4-epimerase to UDP-galactose. Two molecules of galactose were linked to N-acetylglucosamine subsequently with a Helicobacter pylori β-l,4-galactosyltransferase and a Neisseria meningitidis α-1,4-galactosyltransferase to produce one molecule of P1 trisaccharide. The four enzymes were coexpressed in a single genetically engineered E. coli strain that was then permeabilized and used to catalyze the enzymatic reaction. P1 trisaccharide was accumulated up to 50 mM (5.4 g in a 200-ml reaction volume), with a 67% yield based on the consumption of N-acetylglucosamine. This study provides an efficient approach for the preparative-scale synthesis of P1 trisaccharide with recombinant bacteria.

scholarly journals Unexpected Stress-Reducing Effect of PhaP, a Poly(3-Hydroxybutyrate) Granule-Associated Protein, in Escherichia coli

2011 ◽  
Vol 77 (18) ◽  
pp. 6622-6629 ◽  
Author(s):  
Alejandra de Almeida ◽  
Mariela V. Catone ◽  
Virgil A. Rhodius ◽  
Carol A. Gross ◽  
M. Julia Pettinari
Keyword(s):  
Escherichia Coli ◽  
Heat Shock ◽  
Stress Proteins ◽  
Protective Role ◽  
Pcr Analysis ◽  
Content Type ◽  
E Coli ◽  
Protein Levels ◽  
Stress Related Genes ◽  
Heat Stress Proteins

ABSTRACTPhasins (PhaP) are proteins normally associated with granules of poly(3-hydroxybutyrate) (PHB), a biodegradable polymer accumulated by many bacteria as a reserve molecule. These proteins enhance growth and polymer production in natural and recombinant PHB producers. It has been shown that the production of PHB causes stress in recombinantEscherichia coli, revealed by an increase in the concentrations of several heat stress proteins. In this work, quantitative reverse transcription (qRT)-PCR analysis was used to study the effect of PHB accumulation, and that of PhaP fromAzotobactersp. strain FA8, on the expression of stress-related genes in PHB-producingE. coli. While PHB accumulation was found to increase the transcription ofdnaKandibpA, the expression of these genes and ofgroES,groEL,rpoH,dps, andyfiDwas reduced, when PhaP was coexpressed, to levels even lower than those detected in the non-PHB-accumulating control. These results demonstrated the protective role of PhaP in PHB-synthesizingE. coliand linked the effects of the protein to the expression of stress-related genes, especiallyibpA. The effect of PhaP was also analyzed in non-PHB-synthesizing strains, showing that expression of this heterologous protein has an unexpected protective effect inE. coli, under both normal and stress conditions, resulting in increased growth and higher resistance to both heat shock and superoxide stress by paraquat. In addition, PhaP expression was shown to reduce RpoH protein levels during heat shock, probably by reducing or titrating the levels of misfolded proteins.

Sign in / Sign up

Export Citation Format

Share Document