Genome-wide mapping of cyclic AMP receptor protein binding in Enteroaggregative reveals targeting of virulence-associated genes.

Bacterial pathogens use a wide array of virulence factors to colonise and subsequently elicit disease in their host. These factors are often subject to extensive regulation at the transcriptional level, to ensure that their expression is timely. Although many pathogens use bespoke transcription factors that primarily target virulence genes, global transcription factors also sometimes play a role in controlling these genes.

Genome-wide mapping of cAMP receptor protein binding in enteroaggregative reveals targeting of virulence-associated genes.

Bacterial pathogens employ a diverse array of virulence factors to colonize and subsequently elicit disease in their host. These factors are often subject to extensive regulation at the transcriptional level to ensure that their expression is timely. Although many pathogens use bespoke transcription factors that primarily target virulence genes, global transcription factors also sometimes play a role in controlling these genes.

Genome Characterization of Carbapenem-Resistant Hypervirulent Strains, Carrying Hybrid Resistance-Virulence IncHI1B/FIB Plasmids, Isolated from an Egyptian Pediatric ICU.

Despite the increased reporting of Carbapenem-resistant hypervirulent (CR-hvKp) in Egypt, there is a paucity of information regarding the molecular characteristics of such strains. Herein, we present the genome sequence of two CR-hvKp strains, K22 and K45, which were isolated from VAP (ventilator-associated-pneumonia) patients admitted to pediatric ICU at Assiut University Children's Hospital, Egypt. K22 and K45 isolates were subjected to antimicrobial susceptibility testing and whole-genome sequencing.

Transcription activation in and .

Promoter-specific activation of transcript initiation provides an important regulatory device in and . Here, we describe the different mechanisms that operate, focusing on how they have evolved to manage the "housekeeping" bacterial transcription machinery. Some mechanisms involve assisting the bacterial DNA-dependent RNA polymerase or replacing or remodeling one of its subunits.

Organometallic Pillarplexes That Bind DNA 4-Way Holliday Junctions and Forks.

Holliday 4-way junctions are key to important biological DNA processes (insertion, recombination, and repair) and are dynamic structures that adopt either open or closed conformations, the open conformation being the biologically active form. Tetracationic metallo-supramolecular pillarplexes display aryl faces about a cylindrical core, an ideal structure to interact with open DNA junction cavities. Combining experimental studies and MD simulations, we show that an Au pillarplex can bind DNA 4-way (Holliday) junctions in their open form, a binding mode not accessed by synthetic agents before.

Laboratory strains of K-12: things are seldom what they seem.

K-12 was originally isolated 100 years ago and since then it has become an invaluable model organism and a cornerstone of molecular biology research. However, despite its pedigree, since its initial isolation K-12 has been repeatedly cultured, passaged and mutagenized, resulting in an organism that carries many genetic changes. To understand more about this important model organism, we have sequenced the genomes of two ancestral K-12 strains, WG1 and EMG2, considered to be the progenitors of many key laboratory strains.

Control of resistance against bacteriophage killing by a metabolic regulator in meningitis-associated .

Ecologically beneficial traits in bacteria are encoded by intrinsic and horizontally acquired genes. However, such traits are not universal, and the highly mosaic nature of bacterial genomes requires control at the transcriptional level to drive these processes. It has emerged that regulatory flexibility is widespread in the species, whereby preexisting transcription factors can acquire new and unrelated roles in regulating beneficial traits.

New vectors for urea-inducible recombinant protein production.

We have developed a novel urea-inducible recombinant protein production system by exploiting the Proteus mirabilis urease ureR-ureD promoter region and the ureR AraC-family transcriptional regulator. Experiments using the expression of β-galactosidase and green fluorescent protein (GFP) showed that promoter activity is tightly regulated and that varying the concentration of urea can give up to 100-fold induction. Production of proteins of biopharmaceutical interest has been demonstrated, including human growth hormone (hGH), a single chain antibody fragment (scFv) against interleukin-1β and a potential Neisserial vaccine candidate (BamA).

Novel organisation and regulation of the promoter from enteroaggregative and uropathogenic .

The serine protease autotransporters of the (SPATEs) are a large family of virulence factors commonly found in enteric bacteria. These secreted virulence factors have diverse functions during bacterial infection, including adhesion, aggregation and cell toxicity. One such SPATE, the Pic mucinase (protein involved in colonisation) cleaves mucin, allowing enteric bacterial cells to utilise mucin as a carbon source and to penetrate the gut mucus lining, thereby increasing mucosal colonisation.

Heterologous Expression of Membrane Proteins in E. coli.

Over the decades, the bacterium Escherichia coli (E. coli) has become the cornerstone of recombinant protein production, used for heterologous synthesis of a variety of membrane proteins. Due to its rapid growth to high densities in cheap media, and its ease of manipulation and handling, E.

Inexpensive protein overexpression driven by the NarL transcription activator protein.

Most Escherichia coli overexpression vectors used for recombinant protein production (RPP) depend on organic inducers, for example, sugars or simple conjugates. However, these can be expensive and, sometimes, chemically unstable. To simplify this and to cut the cost of RPP, we have developed vectors controlled by the Escherichia coli nitrate-responsive NarL transcription activator protein, which use nitrate, a cheap, stable, and abundant inorganic ion, to induce high-level controlled RPP.

The Small DdrR Protein Directly Interacts with the UmuDAb Regulator of the Mutagenic DNA Damage Response in Acinetobacter baumannii.

Acinetobacter baumannii poses a great threat in health care settings worldwide, with clinical isolates displaying an ever-evolving multidrug resistance. In strains of A. baumannii, expression of multiple error-prone polymerase genes are corepressed by UmuDAb, a member of the LexA superfamily, and a small protein, DdrR.

Genome-wide association studies reveal the role of polymorphisms affecting factor H binding protein expression in host invasion by Neisseria meningitidis.

Many invasive bacterial diseases are caused by organisms that are ordinarily harmless components of the human microbiome. Effective interventions against these microbes require an understanding of the processes whereby symbiotic or commensal relationships transition into pathology. Here, we describe bacterial genome-wide association studies (GWAS) of Neisseria meningitidis, a common commensal of the human respiratory tract that is nevertheless a leading cause of meningitis and sepsis.

Antimicrobial Resistance and Comparative Genome Analysis of Strains Isolated in Egypt.

is an important human pathogen in both developing and industrialised countries that can causes a variety of human infections, such as pneumonia, urinary tract infections and bacteremia. Like many Gram-negative bacteria, it is becoming resistant to many frontline antibiotics, such as carbapenem and cephalosporin antibiotics. In Egypt, is increasingly recognised as an emerging pathogen, with high levels of antibiotic resistance.

The PAR promoter expression system: Modified lac promoters for controlled recombinant protein production in Escherichia coli.

Many commonly used bacterial promoters employed for recombinant protein production (RPP) in Escherichia coli are capable of high-level protein expression. However, such promoter systems are often too strong, being ill suited for expressing proteins that are difficult to fold, targeted to the membrane or secreted out of the cytoplasm. To circumvent this problem, a suite of bacterial promoters has been constructed with a range of different promoter strengths, assigning them specific "promoter activity ratings" (PARs).

BamA and BamD Are Essential for the Secretion of Trimeric Autotransporter Adhesins.

Unlabelled: The BAM complex in is composed of five proteins, BamA-E. BamA and BamD are essential for cell viability and are required for the assembly of β-barrel outer membrane proteins. Consequently, BamA and BamD are indispensable for secretion via the classical autotransporter pathway (Type 5a secretion).

Antimicrobial resistance and gene regulation in Enteroaggregative Escherichia coli from Egyptian children with diarrhoea: Similarities and differences.

Enteroaggregative (EAEC) is a common diarrhoeagenic human pathogen, isolated from patients in both developing and industrialized countries, that is becoming increasingly resistant to many frontline antibiotics. In this study, we screened 50 strains from children presenting with diarrhea at the outpatients clinic of Assiut University Children's Hospital, Egypt. We show that all of these isolates were resistant to multiple classes of antibiotics and identified two as being typical EAEC strains.

Rotaxanating Metallo-supramolecular Nano-cylinder Helicates to Switch DNA Junction Binding.

A class of rotaxane is created, not by encapsulating a conventional linear thread, but rather by wrapping a large cucurbit[10]uril macrocycle about a three-dimensional, cylindrical, nanosized, self-assembled supramolecular helicate as the axle. The resulting pseudo-rotaxane is readily converted into a proper interlocked rotaxane by adding branch points to the helicate strands that form the surface of the cylinder (like branches and roots on a tree trunk). The supramolecular cylinder that forms the axle is itself a member of a unique and remarkable class of helicate metallo-drugs that bind Y-shaped DNA junction structures and induce cell death.

An ideal spacing is required for the control of Class II CRP-dependent promoters by the status of CRP K100.

Transcription activation by the Escherichia coli CRP at Class II promoters is dependent on direct interactions between RNA polymerase and CRP, therefore the spatial proximity between both proteins plays a significant role in the ability of CRP to activate transcription. Using both in vivo and in vitro techniques, here we demonstrate that the CRP K100 positive charge, adjacent to AR2, is required for full promoter activity when CRP is optimally positioned. Accordingly, K100 mediated activation is very position-dependent and our data confirm that the largest impact of the K100 status on transcription activation occurs when the spacing between the CRP binding site and the A2 of the -10 element is 22 bp.

Activation by NarL at the Escherichia coli ogt promoter.

The Escherichia coli NarX/NarL two-component response-regulator system regulates gene expression in response to nitrate ions and the NarL protein is a global transcription factor, which activates transcript initiation at many target promoters. One such target, the E. coli ogt promoter, which controls the expression of an O6-alkylguanine-DNA-alkyltransferase, is dependent on NarL binding to two DNA targets centred at positions -44.

Distinct intraspecies virulence mechanisms regulated by a conserved transcription factor.

Tailoring transcriptional regulation to coordinate the expression of virulence factors in tandem with the core genome is a hallmark of bacterial pathogen evolution. Bacteria encode hundreds of transcription factors forming the base-level control of gene regulation. Moreover, highly homologous regulators are assumed to control conserved genes between members within a species that harbor the same genetic targets.

Escherichia coli "TatExpress" strains export several g/L human growth hormone to the periplasm by the Tat pathway.

Escherichia coli is a heavily used platform for the production of biotherapeutic and other high-value proteins, and a favored strategy is to export the protein of interest to the periplasm to simplify downstream processing and facilitate disulfide bond formation. The Sec pathway is the standard means of transporting the target protein but it is unable to transport complex or rapidly folding proteins because the Sec system can only transport proteins in an unfolded state. The Tat system also operates to transport proteins to the periplasm, and it has significant potential as an alternative means of recombinant protein production because it transports fully folded proteins.

Bacterial Transcription Factors: Regulation by Pick "N" Mix.

Transcription in most bacteria is tightly regulated in order to facilitate bacterial adaptation to different environments, and transcription factors play a key role in this. Here we give a brief overview of the essential features of bacterial transcription factors and how they affect transcript initiation at target promoters. We focus on complex promoters that are regulated by combinations of activators and repressors, combinations of repressors only, or combinations of activators.