Studies on the endogenous metabolism of <i>Escherichia coli</i>

Dawes, E. A.; Ribbons, D. W.

doi:10.1042/bj0960577_b1a

Cited by 20 publications

(28 citation statements)

References 0 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The gradual decrease of swimming speed with time observed in Fig. 3D for all magnitudes of osmotic upshocks was previously characterized in Motility Buffer, where E. coli maintains Proton Motive Force (PMF) using endogenous energy sources [Dawes andRibbons, 1965, Schwarz-Linek et al, 2016]. At fixed buffer composition, the time it takes to consume all available oxygen is inversely proportional to the cell concentration, and upon oxygen exhaustion a sudden 'crash' in swimming speed occurs [Schwarz-Linek et al, 2016].…”

Section: Osmotic Response Shows Osmokinesis Ie Changes In Motor Speedmentioning

confidence: 94%

Osmotaxis in Escherichia coli through changes in motor speed

Rosko

Martinez

Poon

et al. 2017

Proc. Natl. Acad. Sci. U.S.A.

View full text Add to dashboard Cite

Bacterial motility, and in particular repulsion or attraction towards specific chemicals, has been a subject of investigation for over 100 years, resulting in detailed understanding of bacterial chemotaxis and the corresponding sensory network in many bacterial species. For Escherichia coli most of the current understanding comes from the experiments with low levels of chemotactically-active ligands. However, chemotactically-inactive chemical species at concentrations found in the human gastrointestinal tract produce significant changes in E. coli's osmotic pressure, and have been shown to lead to taxis. To understand how these nonspecific physical signals influence motility, we look at the response of individual bacterial flagellar motors under step-wise changes in external osmolarity. We combine these measurements with a population swimming assay under the same conditions. Unlike for chemotactic response, a long term increase in swimming/motor speeds is observed, and in the motor rotational bias, both of which scale with the osmotic shock magnitude. We discuss how the speed changes we observe can lead to steady state bacterial accumulation.

show abstract

Section: Osmotic Response Shows Osmokinesis Ie Changes In Motor Speedmentioning

confidence: 94%

Osmotaxis in Escherichia coli through changes in motor speed

Rosko

Martinez

Poon

et al. 2017

Proc. Natl. Acad. Sci. U.S.A.

View full text Add to dashboard Cite

show abstract

“…At first, this may seem paradoxical but, in fact, since both sets of enzymes are present, the cell is poised at any given moment to either make glycogen or degrade it, as conditions allow. Recall that glycogen is formed when carbon is in excess but some other nutrient is limiting and glycogen is degraded when carbon is limiting (13,36). Moreover, glycogen is synthesized from glucose-1-phosphate, which is also the breakdown product of glycogen.…”

Section: Discussionmentioning

confidence: 99%

“…However, GlgS has no defined role in glycogen synthesis, although its crystal structure suggests involvement in protein-protein interactions (25). Glycogen degradation occurs when carbon sources become limiting (13). GlgP, glycogen phosphorylase, catalyzes glycogen breakdown by removing glucose units from the polysaccharide.…”

mentioning

confidence: 99%

Glycogen and Maltose Utilization by Escherichia coli O157:H7 in the Mouse Intestine

et al. 2008

View full text Add to dashboard Cite

Mutant screens and transcriptome studies led us to consider whether the metabolism of glucose polymers, i.e., maltose, maltodextrin, and glycogen, is important for Escherichia coli colonization of the intestine. By using the streptomycin-treated mouse model, we found that catabolism of the disaccharide maltose provides a competitive advantage in vivo to pathogenic E. coli O157:H7 and commensal E. coli K-12, whereas degradation of exogenous forms of the more complex glucose polymer, maltodextrin, does not. The endogenous glucose polymer, glycogen, appears to play an important role in colonization, since mutants that are unable to synthesize or degrade glycogen have significant colonization defects. In support of the hypothesis that E. coli relies on internal carbon stores to maintain colonization during periods of famine, we found that by providing a constant supply of a readily metabolized sugar, i.e., gluconate, in the animal's drinking water, the competitive disadvantage of E. coli glycogen metabolism mutants is rescued. The results suggest that glycogen storage may be widespread in enteric bacteria because it is necessary for maintaining rapid growth in the intestine, where there is intense competition for resources and occasional famine. An important implication of this study is that the sugars used by E. coli are present in limited quantities in the intestine, making endogenous carbon stores valuable. Thus, there may be merit to combating enteric infections by using probiotics or prebiotics to manipulate the intestinal microbiota in such a way as to limit the availability of sugars preferred by E. coli O157:H7 and perhaps other pathogens.

show abstract

“…Survival limits of several hours or a few days have been reported for these latter organisms when removed from a growing culture and starved: Aerobacter aerogenes, 45 h (Strange, Dark & Ness, 1961); Escherichia coli, 36 h (Dawes & Ribbons, 1965); Pseudomonas aeruginosa, 84 h (Clifton, 1967); Salmonella enteritidis, 140 h (Druilhet & Sobek, 1976); and Streptococcus lactis, 30 h (Thomas & Batt, 1968). We conclude from this study that the coryneform bacteria as a group have evolved adaptive mechanisms to natural conditions where low nutrient supplies are common, whereas those bacteria associated with higher organisms, plentiful nutrient supplies, and less intense selective pressures show considerably shortened survival limits.…”

Section: Discussionmentioning

confidence: 99%

“…Ribonucleic acid and protein are consumed during starvation to varying degrees often related to the substrate on which the organism has been grown (Dawes & Ribbons, 1965;Strange, Wade & Ness, 1963;Thomas & Batt, 1969;Willetts, 1967). Deoxyribonucleic acid is not a consumable substrate.…”

Section: W Boylen a N D M H M U L K Smentioning

confidence: 99%

The Survival of Coryneform Bacteria during Periods of Prolonged Nutrient Starvation

Boylen

Mulks

1978

Journal of General Microbiology

View full text Add to dashboard Cite

Cultures of 16 coryneform bacteria were grown to late-exponential stage in nutrient media, washed, and starved in 30 mwpotassium phosphate buffer pH 7.0, with no external energy or carbon source. After 4 weeks starvation, 20 to 98 yo of each culture was still viable; after 8 weeks, 5 to 70% of each culture was still viable. Little change in cell shape or size was detected in Arthrobacter globiformis, A . nicotianae, Brevibacterium linens, Corynebacterium fascians, Mycobacterium rhodochrous and Nocardia roseum when studied by electron microscopy for up to 56 d, although there was a gradual disappearance of intracellular material. No resting structures were discernible. All organisms showed an immediate decrease in endogenous respiration to less than 1 of that observed during growth. A low basal level of endogenous metabolism equivalent to 0.01 to 0.03 % of cellular carbon oxidized to C 0 2 h-l was maintained for 56 d. Carbohydrate, intracellular pools, protein, ribonucleic acid and deoxyribonucleic acid were utilized at varying rates by different organisms during this period. All species were effective in maintaining 20 to 70% of their Mg2+ content during a 28 d starvation period in the absence of any external Mg2+. It would appear that the soil coryneform bacteria possess similar survival characteristics in laboratory studies which could explain, in part, their ecological success in natural environments.

show abstract

Studies on the endogenous metabolism of Escherichia coli

Cited by 20 publications

References 0 publications

Osmotaxis in Escherichia coli through changes in motor speed

Osmotaxis in Escherichia coli through changes in motor speed

Glycogen and Maltose Utilization by Escherichia coli O157:H7 in the Mouse Intestine

The Survival of Coryneform Bacteria during Periods of Prolonged Nutrient Starvation

Contact Info

Product

Resources

About