Drug efflux machinery inherited asymmetrically In dividing bacterial cells, asymmetric distribution of cell wall constituents occurs between mother cells and their progeny. Asymmetric in a growing population results heterogeneity antibiotic resistance. One consequence is that the presence low levels antibiotic, older tend to live longer than younger cells. Using microfluidic device trap measure Bergmiller et al. showed AcrAB-TolC, main multidrug pump Escherichia coli , clusters at pole (see...

Bacteria in groups vary individually, and interact with other bacteria the environment to produce population-level patterns of gene expression. Investigating such behavior detail requires measuring controlling populations at single-cell level alongside precisely specified interactions environmental characteristics. Here we present an automated, programmable platform that combines image-based expression growth measurements on-line optogenetic control for hundreds individual Escherichia coli...

Essential genes code for fundamental cellular functions required the viability of an organism. For this reason, essential are often highly conserved across organisms. However, is not always case: orthologues that in one organism sometimes other organisms or absent from their genomes. This suggests that, course evolution, can be rendered nonessential. How a gene become non-essential? Here we used genetic manipulation to deplete products 26 different Escherichia coli. depletion results lethal...

The bacterial flagellum is a self-assembling nanomachine. external flagellar filament, several times longer than cell body, made of few tens thousands subunits single protein: flagellin. A fundamental problem concerns the molecular mechanism how grows outside cell, where no discernible energy source available. Here, we monitored dynamic assembly individual flagella using in situ labelling and real-time immunostaining elongating filaments. We report that rate growth, initially ∼1,700 amino...

High relatedness among interacting individuals has generally been considered a precondition for the evolution of altruism. However, kin-selection theory also predicts altruism when is low, as long cost altruistic act minor compared with its benefit. Here, we demonstrate evidence low-cost in bacteria. We investigated Escherichia coli responding to attack an obligately lytic phage by committing suicide order prevent parasite transmission nearby relatives. found that bacterial provides large...

While we have good understanding of bacterial metabolism at the population level, know little about metabolic behavior individual cells: do single cells in clonal populations sometimes specialize on different pathways? Such specialization could be driven by stochastic gene expression and provide with growth benefits specialization. We measured degree phenotypic two parallel pathways, assimilation glucose arabinose. grew Escherichia coli chemostats, used isotope-labeled sugars combination...

Clustered Regularly Interspaced Short Palindromic Repeats interference (CRISPRi), based on catalytically dead Cas9 nuclease of Streptococcus pyogenes , is a programmable and highly flexible tool to investigate gene function essentiality in bacteria due its ability block transcription elongation at nearly any desired DNA target. In this study, I assess how CRISPRi can be programmed control the life cycle infectivity Escherichia coli bacteriophage T7, virulent obligatory lytic phage. This...

Which properties of metabolic networks can be derived solely from stoichiometric information about the network's constituent reactions? Predictive results have been obtained by Flux Balance Analysis (FBA), postulating that cells set fluxes within allowed stoichiometry so as to maximize their growth. Here, we generalize this framework single cell level using maximum entropy models statistical physics. We define and compute, for core metabolism Escherichia coli, a joint distribution over all...

Antibiotics, by definition, reduce bacterial growth rates in optimal culture conditions; however, the real-world environments bacteria inhabit see rapid punctuated periods of low nutrient availability. How antibiotics mediate population decline during these is poorly understood. Bacteria cannot optimize for all environmental conditions because a growth-longevity tradeoff predicts faster results decline, and since bacteriostatic slow growth, they should also longevity. We quantify how...

Parasitism creates selection for resistance mechanisms in host populations and is hypothesized to promote increased evolvability. However, the influence of these traits on evolution when parasites are no longer present unclear. We used experimental whole-genome sequencing Escherichia coli determine effects past exposure parasitic viruses (phages) spread mutator alleles, resistance, bacterial competitive fitness. found that alleles rapidly during adaptation any four different phage species,...

The MazF toxin sequence-specifically cleaves single-stranded RNA upon various stressful conditions, and it is activated as a part of the mazEF toxin-antitoxin module in Escherichia coli. Although autoregulation expression through MazE antitoxin-dependent transcriptional repression has been biochemically characterized, less known about post-transcriptional autoregulation, well how both these autoregulatory features affect growth single cells during conditions that promote production. Here, we...

Strains of Escherichia coli lacking MalQ (maltodextrin glucanotransferase or amylomaltase) are endogenously induced for the maltose regulon by maltotriose that is derived from degradation glycogen (glycogen-dependent endogenous induction). A high level induction was dependent on presence MalP, maltodextrin phosphorylase, while expression counteracted MalZ, glucosidase. Glycogen-derived sensitive to osmolarity. This osmodependence caused MalZ. malZ, gene encoding this enzyme, found be...

Gene duplication is important in evolution, because it provides new raw material for evolutionary adaptations. Several existing hypotheses about the causes of duplicate retention and diversification differ their emphasis on gene dosage, subfunctionalization, neofunctionalization. Little experimental data exist relative importance expression changes coding regions evolution genes. Furthermore, we do not know how strongly environment could affect this importance. To address these questions,...

ABSTRACT A number of recent experiments at the single-cell level have shown that genetically identical bacteria live in homogeneous environments often show a substantial degree phenotypic variation between cells. Often, this is attributed to stochastic aspects biology—the fact many biological processes involve small numbers molecules and are thus inherently variable. However, not all cells needs be nature; one deterministic process could important for cell variability some bacterial species...

The essential Escherichia coli gene ygjD belongs to a universally conserved group of genes whose function has been the focus number recent studies. Here, we put under control an inducible promoter, and used time-lapse microscopy single cell analysis investigate phenotypic consequences depletion YgjD protein from growing cells. We show that loss leads marked decrease in size termination division. transition towards smaller occurs controlled manner: elongation division remain coupled, but at...

In bacteria, replicative aging manifests as a difference in growth or survival between the two cells emerging from division. One cell can be regarded an mother with decreased potential for future and division, other rejuvenated daughter. Here, we aimed at investigating some of processes involved bacterium Escherichia coli, where types distinguished by age their poles. We found that certain changes regulation carbohydrate metabolism affect aging. A mutation carbon storage regulator gene,...

Abstract To determine the dosage at which antibiotic resistance evolution is most rapid, we treated Escherichia coli in vitro, deploying erythromycin dosages ranging from zero to high. Adaptation was fastest just below erythromycin’s minimal inhibitory concentration (MIC) and genotype-phenotype correlations determined whole genome sequencing revealed molecular basis: simultaneous selection for copy number variation three mechanisms exhibited an “inverted-U” pattern of dose-dependence, as did...

Abstract CRISPR interference (CRISPRi) based on catalytically dead Cas9 nuclease of Streptococcus pyogenes is a programmable and highly flexible tool to interrogate gene function essentiality in bacteria due its ability block transcription elongation at nearly any desired DNA target. Here, I assess how CRISPRi-dCas9 can be programmed control the life cycle infectivity Escherichia coli bacteriophage T7, virulent obligatory lytic phage, by blocking critical host-dependent promoters that are...

ABSTRACT Bacteria have evolved a wide range of defense strategies to protect themselves against bacterial viruses (phages). However, the known mechanisms almost exclusively target phages with DNA genomes. While several toxin-antitoxin systems been considered cleave single-stranded RNA in response stressful conditions, their role protecting bacteria genomes has not studied. Here we investigate representative system, MazEF, Escherichia coli two – MS2 and Qβ. Our population-level experiments...

We treated Escherichia coli with the antibiotic erythromycin from zero to high dosages determine how evolutionary dynamics of resistant phenotypes and genotypes depend on dose. The most rapid increase in resistance was observed just below erythromycin’s minimal inhibitory concentration (MIC) genotype-phenotype correlations determined whole genome sequencing revealed molecular basis this: simultaneous selection for copy number variation 3 mechanisms which shared an ‘inverted-U’ pattern...

Fisher suggested advantageous genes would spread through populations as a wave so we sought genetic waves in evolving populations, follows. By fusing fluorescent marker to drug efflux protein (AcrB) whose expression provides Escherichia coli with resistance some antibiotics, quantified the evolution and of drug-resistant E. spacetime using image analysis quantitative PCR. As is done hospitals routinely, exposed bacterium gradient antibiotic ‘disk diffusion’ susceptibility test that videoed....