Aminoglycoside Antibiotics Inhibit Phage Infection by Blocking an Early Step of the Infection Cycle.

In response to viral predation, bacteria have evolved a wide range of defense mechanisms, which rely mostly on proteins acting at the cellular level. Here, we show that aminoglycosides, a well-known class of antibiotics produced by , are potent inhibitors of phage infection in widely divergent bacterial hosts. We demonstrate that aminoglycosides block an early step of the viral life cycle, prior to genome replication.

Biosensor-based isolation of amino acid-producing strains.

The marine bacterium has recently been demonstrated to be a promising new host for molecular biology and next generation bioprocesses. is a Gram-negative, non-pathogenic slight-halophilic bacterium, with a high nutrient versatility and a reported doubling time of under 10 min. However, is not an established model organism yet, and further research is required to promote its transformation into a microbial workhorse.

Inducible Expression Systems Based on Xenogeneic Silencing and Counter-Silencing and Design of a Metabolic Toggle Switch.

Inducible expression systems represent key modules in regulatory circuit design and metabolic engineering approaches. However, established systems are often limited in terms of applications due to high background expression levels and inducer toxicity. In bacteria, xenogeneic silencing (XS) proteins are involved in the tight control of horizontally acquired, AT-rich DNA.

Deciphering the Rules Underlying Xenogeneic Silencing and Counter-Silencing of Lsr2-like Proteins Using CgpS of Corynebacterium glutamicum as a Model.

Lsr2-like nucleoid-associated proteins play an important role as xenogeneic silencers (XS) of horizontally acquired genomic regions in actinobacteria. In this study, we systematically analyzed the constraints underlying silencing and counter-silencing of the Lsr2-like protein CgpS in Genome-wide analysis revealed binding of CgpS to regions featuring a distinct drop in GC profile close to the transcription start site (TSS) but also identified an overrepresented motif with multiple A/T steps at the nucleation site of the nucleoprotein complex. Binding of specific transcription factors (TFs) may oppose XS activity, leading to counter-silencing.

Impact of CO/HCO Availability on Anaplerotic Flux in Pyruvate Dehydrogenase Complex-Deficient Corynebacterium glutamicum Strains.

The pyruvate dehydrogenase complex (PDHC) catalyzes the oxidative decarboxylation of pyruvate, yielding acetyl coenzyme A (acetyl-CoA) and CO The PDHC-deficient Δ strain therefore lacks an important decarboxylation step in its central metabolism. Additional inactivation of , encoding pyruvate carboxylase, resulted in a >15-h lag phase in the presence of glucose, while no growth defect was observed on gluconeogenetic substrates, such as acetate. Growth was successfully restored by deletion of , encoding the glucose-specific permease of the phosphotransferase system (PTS), thereby linking the observed phenotype to the increased sensitivity of the Δ Δ strain to glucose catabolism.

Evolutionary engineering of Corynebacterium glutamicum.

A unique feature of biotechnology is that we can harness the power of evolution to improve process performance. Rational engineering of microbial strains has led to the establishment of a variety of successful bioprocesses, but it is hampered by the overwhelming complexity of biological systems. Evolutionary engineering represents a straightforward approach for fitness-linked phenotypes (e.

Screening of an Escherichia coli promoter library for a phenylalanine biosensor.

In recent years, the application of transcription factor-based biosensors for the engineering of microbial production strains opened up new opportunities for industrial biotechnology. However, the design of synthetic regulatory circuits depends on the selection of suitable transcription factor-promoter pairs to convert the concentration of effector molecules into a measureable output. Here, we present an efficient strategy to screen promoter libraries for appropriate parts for biosensor design.

Identification of Dck1 and Lmo1 as upstream regulators of the small GTPase Rho5 in Saccharomyces cerevisiae.

The exact function and regulation of the small GTPase Rho5, a putative homolog of mammalian Rac1, in the yeast Saccharomyces cerevisiae have not yet been elucidated. In a genetic screen initially designed to identify novel regulators of cell wall integrity signaling, we identified the homologs of mammalian DOCK1 (Dck1) and ELMO (Lmo1) as upstream components which regulate Rho5. Deletion mutants in any of the encoding genes (DCK1, LMO1, RHO5) showed hyper-resistance to cell wall stress agents, demonstrating a function in cell wall integrity signaling.

The small GTP-binding proteins AgRho2 and AgRho5 regulate tip-branching, maintenance of the growth axis and actin-ring-integrity in the filamentous fungus Ashbya gossypii.

GTPases of the Rho family are important molecular switches that regulate many basic cellular processes. The function of the Rho2 and Rho5 proteins from Saccharomyces cerevisiae and of their homologs in other species is poorly understood. Here, we report on the analysis of the AgRho2 and AgRho5 proteins of the filamentous fungus Ashbya gossypii.