scholarly journals Exploring the onset of B12-based mutualisms using a recently evolved Chlamydomonas auxotroph and B12-producing bacteria

2022 ◽  
Author(s):  
Freddy Bunbury ◽  
Evelyne Deery ◽  
Andrew Sayer ◽  
Vaibhav Bhardwaj ◽  
Ellen Harrison ◽  
...  
Keyword(s):  
Gene Loss ◽  
Coli Strain ◽  
Wild Type ◽  
Mesorhizobium Loti ◽  
E Coli ◽  
Dependent Strain ◽  
Metabolic Reactions ◽  
Drive Gene ◽  
The Right ◽  
Preferential Access

Cobalamin (vitamin B12), is a cofactor for crucial metabolic reactions in multiple eukaryotic taxa, including major primary producers such as algae, and yet only prokaryotes can produce it. Many bacteria can colonise the algal phycosphere, forming stable communities that gain preferential access to exudates and in return provide compounds, such as B12. Extended coexistence can then drive gene loss, leading to greater algal-bacterial interdependence. In this study, we investigate how a recently evolved B12-dependent strain of Chlamydomonas reinhardtii, metE7, forms a mutualism with certain bacteria, including the rhizobium Mesorhizobium loti and even a strain of the gut bacterium E. coli engineered to produce cobalamin. Although metE7 was supported by B12 producers, its growth in co-culture was slower than the B12-independent wild-type, suggesting that high bacterial B12 provision may be necessary to favour B12 auxotrophs and their evolution. Moreover, we found that an E. coli strain that releases more B12 makes a better mutualistic partner, and although this trait may be more costly in isolation, greater B12 release provided an advantage in co-cultures. We hypothesise that, given the right conditions, bacteria that release more B12 may be selected for, particularly if they form close interactions with B12-dependent algae.

scholarly journals Complete Genome Sequence of the Wild-Type Commensal Escherichia coli Strain SE15, Belonging to Phylogenetic Group B2

2009 ◽  
Vol 192 (4) ◽  
pp. 1165-1166 ◽  
Author(s):  
Hidehiro Toh ◽  
Kenshiro Oshima ◽  
Atsushi Toyoda ◽  
Yoshitoshi Ogura ◽  
Tadasuke Ooka ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Genome Sequence ◽  
Complete Genome Sequence ◽  
Complete Genome ◽  
Healthy Adult ◽  
Coli Strain ◽  
Phylogenetic Group ◽  
Wild Type ◽  
Commensal Bacterium ◽  
E Coli

ABSTRACT Escherichia coli SE15 (O150:H5) is a human commensal bacterium recently isolated from feces of a healthy adult and classified into E. coli phylogenetic group B2, which includes the majority of extraintestinal pathogenic E. coli. Here, we report the finished and annotated genome sequence of this organism.

Isolation and characterization of catabolite repression-resistant mutants of Escherichia coli

1977 ◽  
Vol 23 (10) ◽  
pp. 1384-1393 ◽  
Author(s):  
Glen D. Armstrong ◽  
Hiroshi Yamazaki
Keyword(s):  
Escherichia Coli ◽  
Catabolite Repression ◽  
Coli Strain ◽  
Wild Type ◽  
Phosphotransferase System ◽  
E Coli ◽  
Isolation And Characterization ◽  
In The Wild ◽  
Resistant Mutants

A method has been developed for the isolation of Escherichia coli mutants which are resistant to catabolite repression. The method is based on the fact that a mixture of glucose and gluconate inhibits the development of chemotactic motility in the wild type, but not in the mutants. A motile E. coli strain was mutagenized and grown in glucose and gluconate. Mutants which were able to swim into a tube containing a chemotactic attractant (aspartic acid) were isolated. Most of these mutants were able to produce β-galactosidase in the presence of glucose and gluconate and were normal in their ability to degrade adenosine 3′,5′-cyclic monophosphate. Some of these mutants were defective in the glucose phosphotransferase system.

scholarly journals ShiF acts as an auxiliary factor of aerobactin secretion in meningitis Escherichia coli strain S88

2019 ◽  
Vol 19 (1) ◽  
Author(s):  
Mathieu Genuini ◽  
Philippe Bidet ◽  
Jean-François Benoist ◽  
Dimitri Schlemmer ◽  
Chloé Lemaitre ◽  
...  
Keyword(s):  
Wild Type Strain ◽  
Maximum Growth ◽  
Coli Strain ◽  
Transcriptional Analysis ◽  
Neonatal Meningitis ◽  
Liquid Chromatography Mass Spectrometry ◽  
Wild Type ◽  
E Coli ◽  
Auxiliary Factor

Abstract Background The neonatal meningitis E. coli (NMEC) strain S88 carries a ColV plasmid named pS88 which is involved in meningeal virulence. Transcriptional analysis of pS88 in human serum revealed a strong upregulation of an ORF of unknown function: shiF, which is adjacent to the operon encoding the siderophore aerobactin. The aim of this work is to investigate the role of shiF in aerobactin production in strain S88. Results Study of the prevalence of shiF and aerobactin operon in a collection of 100 extra-intestinal pathogenic E. coli strains (ExPEC) and 50 whole genome-sequenced E. coli strains revealed the colocalization of these two genes for 98% of the aerobactin positive strains. We used Datsenko and Wanner’s method to delete shiF in two S88 mutants. A cross-feeding assay showed that these mutants were able to excrete aerobactin meaning that shiF is dispensable for aerobactin excretion. Our growth assays revealed that the shiF-deleted mutants grew significantly slower than the wild-type strain S88 in iron-depleted medium with a decrease of maximum growth rates of 23 and 28% (p < 0.05). Using Liquid Chromatography-Mass Spectrometry, we identified and quantified siderophores in the supernatants of S88 and its shiF deleted mutants after growth in iron-depleted medium and found that these mutants secreted significantly less aerobactin than S88 (− 52% and - 49%, p < 0.001). Conclusions ShiF is physically and functionally linked to aerobactin. It provides an advantage to E. coli S88 under iron-limiting conditions by increasing aerobactin secretion and may thus act as an auxiliary virulence factor.

scholarly journals A killed, genetically engineered derivative of a wild-type extraintestinal pathogenic E. coli strain is a vaccine candidate

Vaccine ◽  
2007 ◽  
Vol 25 (19) ◽  
pp. 3859-3870 ◽  
Author(s):  
Thomas A. Russo ◽  
Janet M. Beanan ◽  
Ruth Olson ◽  
Stacy A. Genagon ◽  
Ulrike MacDonald ◽  
...  
Keyword(s):  
Vaccine Candidate ◽  
Coli Strain ◽  
Genetically Engineered ◽  
Wild Type ◽  
E Coli

scholarly journals Development of a Biofilm Production-Deficient Escherichia coli Strain as a Host for Biotechnological Applications

2006 ◽  
Vol 72 (5) ◽  
pp. 3336-3342 ◽  
Author(s):  
Bong Hyun Sung ◽  
Choong Hoon Lee ◽  
Byung Jo Yu ◽  
Jun Hyoung Lee ◽  
Ju Young Lee ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Transformation Efficiency ◽  
Coli Strain ◽  
Type I ◽  
Wild Type ◽  
Planktonic Cells ◽  
Acid Biosynthesis ◽  
E Coli ◽  
Biofilm Production ◽  
Abiotic Surfaces

ABSTRACT Bacteria form biofilms by adhering to biotic or abiotic surfaces. This phenomenon causes several problems, including a reduction in the transport of mass and heat, an increase in resistance to antibiotics, and a shortening of the lifetimes of modules in bioindustrial fermentors. To overcome these difficulties, we created a biofilm production-deficient Escherichia coli strain, BD123, by deleting genes involved in curli biosynthesis and assembly, Δ(csgG-csgC); colanic acid biosynthesis and assembly, Δ(wcaL-wza); and type I pilus biosynthesis, Δ(fimB-fimH). E. coli BD123 remained mostly in the form of planktonic cells under the conditions tested and became more sensitive to the antibiotics streptomycin and rifampin than the wild-type E. coli MG1655: the growth of BD123 was inhibited by one-fourth of the concentrations needed to inhibit MG1655. In addition, the transformation efficiency of BD123 was about 20 times higher than that of MG1655, and the production and secretion of recombinant proteins were ∼16% and ∼25% greater, respectively, with BD123 than with MG1655. These results indicate that the newly created biofilm production-deficient strain of E. coli displays several key properties that substantially enhance its utility in the biotechnology arena.

scholarly journals The composition of an unusual precursor of 50 S ribosomes in a mutant of Escherichia coli

1976 ◽  
Vol 158 (2) ◽  
pp. 451-456 ◽  
Author(s):  
F Markey ◽  
P F Sims ◽  
D G Wild
Keyword(s):  
Escherichia Coli ◽  
Exponential Growth ◽  
Coli Strain ◽  
Wild Type ◽  
E Coli ◽  
Type Strains

Escherichia coli strain 15–28 is a mutant which during exponential growth contains large amounts of a ‘47S’ ribonucleoprotein precursor to 50S ribosomes. The ‘47S particles’ are more sensitive to ribonuclease than are 50S ribosomes. The 23 S RNA of 47S particles may be slightly undermethylated, but cannot be distinguished from the 23S RNA of 50S ribosomes by sedimentation or electrophoresis. Isolated particles have 10–15% less protein than do 50S ribosomes; proteins L16, L28 and L33 are absent. Comparison with precursor particles studied by other workers in wild-type strains of E. coli suggests that the assembly of 50S ribosomes in strain 15–28 is atypical.

scholarly journals UDP-N-Acetylmuramic Acid l-Alanine Ligase (MurC) Inhibition in atolCMutant Escherichia coli Strain Leads to Cell Death

2014 ◽  
Vol 58 (10) ◽  
pp. 6165-6171 ◽  
Author(s):  
Vaishali Humnabadkar ◽  
K. R. Prabhakar ◽  
Ashwini Narayan ◽  
Sreevalli Sharma ◽  
Supreeth Guptha ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Efflux Pump ◽  
Coli Strain ◽  
Cellular Activity ◽  
Wild Type ◽  
Compound A ◽  
Content Type ◽  
E Coli ◽  
In The Wild ◽  
High Concentrations

ABSTRACTThe Mur ligases play an essential role in the biosynthesis of bacterial peptidoglycan and hence are attractive antibacterial targets. A screen of the AstraZeneca compound library led to the identification of compound A, a pyrazolopyrimidine, as a potent inhibitor ofEscherichia coliandPseudomonas aeruginosaMurC. However, cellular activity againstE. coliorP. aeruginosawas not observed. Compound A was active against efflux pump mutants of both strains. Experiments using anE. colitolCmutant revealed accumulation of the MurC substrate and a decrease in the level of product upon treatment with compound A,indicating inhibition of MurC enzyme in these cells. Such a modulation was not observed in theE. coliwild-type cells. Further, overexpression of MurC in theE. colitolCmutant led to an increase in the compound A MIC by ≥16-fold, establishing a correlation between MurC inhibition and cellular activity. In addition, estimation of the intracellular compound A level showed an accumulation of the compound over time in thetolCmutant strain. A significant compound A level was not detected in the wild-typeE. colistrain even upon treatment with high concentrations of the compound. Therefore, the lack of MIC and absence of MurC inhibition in wild-typeE. coliwere possibly due to suboptimal compound concentration as a consequence of a high efflux level and/or poor permeativity of compound A.

Construction of an Escherichia coli strain which excretes abnormally large amounts of adenosine 3′,5′-cyclic monophosphate

1978 ◽  
Vol 24 (11) ◽  
pp. 1423-1425 ◽  
Author(s):  
Ann D. E. Fraser ◽  
Hiroshi Yamazaki
Keyword(s):  
Escherichia Coli ◽  
Minimal Medium ◽  
Coli Strain ◽  
Coli Cell ◽  
Wild Type ◽  
Camp Phosphodiesterase ◽  
E Coli ◽  
Cyclic Monophosphate ◽  
Glucose Minimal Medium ◽  
P1 Transduction

It has previously been shown that an Escherichia coli CRP− strain 5333 accumulates abnormally large amounts of adenosine 3′,5′-cyclic monophosphate (cAMP). Using P1 transduction, the CRP− character was transferred to E. coli Crookes strain which is deficient for cAMP phosphodiesterase (CPD−). The resulting strain HY22 (CRP−, CPD−) accumulates greater amounts of cAMP both intracellularly and extracellularly than does 5333. In glucose minimal medium, an HY22 cell accumulates 100 times more cAMP intracellularly and excretes cAMP 150 times faster than does a wild-type E. coli cell.

Expression and morphology of enterotoxigenicEscherichia colisurface antigen CS31A inE. coliK12 andVibrio cholerae

2012 ◽  
Vol 58 (6) ◽  
pp. 728-737
Author(s):  
Kathrin Kuehni-Boghenbor ◽  
Helene A. Jordi ◽  
Joachim Frey ◽  
Edy M. Vilei ◽  
Didier Favre ◽  
...  
Keyword(s):  
Diarrheal Disease ◽  
Phase Variation ◽  
Surface Expression ◽  
Coli Strain ◽  
Enterotoxigenic Escherichia Coli ◽  
Wild Type ◽  
Western Blots ◽  
E Coli ◽  
Recombinant Strains ◽  
In The Wild

Enterotoxigenic Escherichia coli (ETEC) is known as a worldwide cause of diarrheal disease. The pathogenesis involves the attachment of the microorganisms to the mucosa and the production of enterotoxins. Surface expression of CS31A fimbriae was assessed by Western blots, dot blots, immunofluorescence, and electron microscopy using negative staining and immunogold labeling. These investigations revealed significant differences in both the morphology of the wild-type and recombinant strains and the antigen exposure of CS31A in the wild-type and recombinant strains. In the wild-type ETEC strain, expression of CS31A was subject to phase variation. The recombinant E. coli strain produced CS31A but was prone to epitope shedding. In Vibrio cholerae vaccine strain CVD 103-HgR, the recombinant CS31A antigen was expressed but was only found intracellularly. Thus, E. coli strains seem to lend themselves better to the development of recombinant vaccines expressing ETEC-specific antigens at the cell’s surface than strains from other orders or genera such as V. cholerae.

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