One of the central aspects of the biological program that guide the development of an organism is embedded in the regulated and sequential expression of genes as development progresses. A large part of this regulation is achieved through the temporal activation and repression of transcriptional initiation by the selective binding of regulatory proteins, such as transcription factors, to promoters during specific stages of development. Thus, being able to globally and precisely identify these processes are important steps in gaining a systems-level insight and understanding of the developmental program. The cell cycle of Caulobacter crescentus, an alpha-proteobacteria that undergoes cell differentiation and asymmetric cell division, has been used extensively as a model organism to study bacterial development. A cyclical and integrated genetic circuit involving five master regulatory proteins, including DnaA, GcrA, CtrA, and SciP, and the DNA methyl-transferase CcrM, whose presence and activities oscillate in space and time, orchestrate the many facets of the Caulobacter cell cycle including DNA replication, DNA methylation, organelle biogenesis, and cytokinesis. This genetic circuit is at the core of the Caulobacter developmental program. While microarrays have shown 19% of mRNAs undergo changes in RNA level during the cell cycle and development, it is unclear exactly which regulatory factors of the core circuit drive the changes in transcription at each specific locus, and how these regulatory factors act combinatorially to effect transcriptional outcomes has not been systematically dissected. In order to achieve these goals and to further define the transcriptional regulatory landscape that guides the cell cycle, a thorough and global analysis of Caulobacter transcription as a function of the cell cycle and developmental progression is needed. In this thesis, I devised a novel protocol combining 5' rapid amplification of cDNA ends (5' RACE) and high-throughput sequencing to globally map the precise locations of transcriptional start sites (TSSs) in the Caulobacter genome, measured their transcription levels at multiple times in the cell cycle, and identified their transcription factor binding sites. Using the TSSs identified and a RNA sequencing dataset, I made a functional annotation of operons and other transcriptional units in the genome. A large number of antisense transcripts were identified, and many of them are within essential cell cycle-regulated genes, including two master regulators, a previous unknown feature of the core cell cycle control circuit. Many critical genes and operons have multiple promoters, and these promoters are often independently regulated. Furthermore, approximately 25% of the cell cycle-regulated promoters are co-regulated by two or more master regulatory proteins of the core genetic circuit. These results revealed surprising transcriptional complexity and uncovered multiple new layers of transcriptional control mediating the bacterial cell cycle and development and represent the first in-depth analysis of TSS control in as a function bacterial cell cycle and developmental progression.

This book constitutes the proceedings of the 11th International Conference on Computational Methods in Systems Biology, CMSB 2013, held in Klosterneuburg, Austria, in September 2013. The 15 regular papers included in this volume were carefully reviewed and selected from 27 submissions. They deal with computational models for all levels, from molecular and cellular, to organs and entire organisms.

This book covers allocation of metals in cells, metal transporter, storage and metalloregulatory proteins, cellular responses to metal ion stress, transcription of genes involved in metal ion homeostasis, uptake of essential metals, metal efflux and other detoxification mechanisms. The book also discusses metal bioreporters for the nanomolar range of concentration and tools to address the metallome. In addition, coverage details specific metals.

Bacteria in various habitats are subject to continuously changing environmental conditions, such as nutrient deprivation, heat and cold stress, UV radiation, oxidative stress, dessication, acid stress, nitrosative stress, cell envelope stress, heavy metal exposure, osmotic stress, and others. In order to survive, they have to respond to these conditions by adapting their physiology through sometimes drastic changes in gene expression. In addition they may adapt by changing their morphology, forming biofilms, fruiting bodies or spores, filaments, Viable But Not Culturable (VBNC) cells or moving away from stress compounds via chemotaxis. Changes in gene expression constitute the main component of the bacterial response to stress and environmental changes, and involve a myriad of different mechanisms, including (alternative) sigma factors, bi- or tri-component regulatory systems, small non-coding RNA’s, chaperones, CHRIS-Cas systems, DNA repair, toxin-antitoxin systems, the stringent response, efflux pumps, alarmones, and modulation of the cell envelope or membranes, to name a few. Many regulatory elements are conserved in different bacteria; however there are endless variations on the theme and novel elements of gene regulation in bacteria inhabiting particular environments are constantly being discovered. Especially in (pathogenic) bacteria colonizing the human body a plethora of bacterial responses to innate stresses such as pH, reactive nitrogen and oxygen species and antibiotic stress are being described. An attempt is made to not only cover model systems but give a broad overview of the stress-responsive regulatory systems in a variety of bacteria, including medically important bacteria, where elucidation of certain aspects of these systems could lead to treatment strategies of the pathogens. Many of the regulatory systems being uncovered are specific, but there is also considerable “cross-talk” between different circuits. Stress and Environmental Regulation of Gene Expression and Adaptation in Bacteria is a comprehensive two-volume work bringing together both review and original research articles on key topics in stress and environmental control of gene expression in bacteria. Volume One contains key overview chapters, as well as content on one/two/three component regulatory systems and stress responses, sigma factors and stress responses, small non-coding RNAs and stress responses, toxin-antitoxin systems and stress responses, stringent response to stress, responses to UV irradiation, SOS and double stranded systems repair systems and stress, adaptation to both oxidative and osmotic stress, and desiccation tolerance and drought stress. Volume Two covers heat shock responses, chaperonins and stress, cold shock responses, adaptation to acid stress, nitrosative stress, and envelope stress, as well as iron homeostasis, metal resistance, quorum sensing, chemotaxis and biofilm formation, and viable but not culturable (VBNC) cells. Covering the full breadth of current stress and environmental control of gene expression studies and expanding it towards future advances in the field, these two volumes are a one-stop reference for (non) medical molecular geneticists interested in gene regulation under stress.

RNAs form complexes with proteins and other RNAs. The RNA‐infrastructure represents the spatiotemporal interaction of these proteins and RNAs in a cell‐wide network. RNA Infrastructure and Networks brings together these ideas to illustrate the scope of RNA‐based biology, and how connecting RNA mechanisms is a powerful tool to investigate regulatory pathways. This book is but a taste of the wide range of RNA‐based mechanisms that connect in the RNA infrastructure.

Lasso peptides form a growing family of fascinating ribosomally-synthesized and post-translationally modified peptides produced by bacteria. They contain 15 to 24 residues and share a unique interlocked topology that involves an N-terminal 7 to 9-residue macrolactam ring where the C-terminal tail is threaded and irreversibly trapped. The ring results from the condensation of the N-terminal amino group with a side-chain carboxylate of a glutamate at position 8 or 9, or an aspartate at position 7, 8 or 9. The trapping of the tail involves bulky amino acids located in the tail below and above the ring and/or disulfide bridges connecting the ring and the tail. Lasso peptides are subdivided into three subtypes depending on the absence (class II) or presence of one (class III) or two (class I) disulfide bridges. The lasso topology results in highly compact structures that give to lasso peptides an extraordinary stability towards both protease degradation and denaturing conditions. Lasso peptides are generally receptor antagonists, enzyme inhibitors and/or antibacterial or antiviral (anti-HIV) agents. The lasso scaffold and the associated biological activities shown by lasso peptides on different key targets make them promising molecules with high therapeutic potential. Their application in drug design has been exemplified by the development of an integrin antagonist based on a lasso peptide scaffold. The biosynthesis machinery of lasso peptides is therefore of high biotechnological interest, especially since such highly compact and stable structures have to date revealed inaccessible by peptide synthesis. Lasso peptides are produced from a linear precursor LasA, which undergoes a maturation process involving several steps, in particular cleavage of the leader peptide and cyclization. The post-translational modifications are ensured by a dedicated enzymatic machinery, which is composed of an ATP-dependent cysteine protease (LasB) and a lactam synthetase (LasC) that form an enzymatic complex called lasso synthetase. Microcin J25, produced by Escherichia coli AY25, is the archetype of lasso peptides and the most extensively studied. To date only around forty lasso peptides have been isolated, but genome mining approaches have revealed that they are widely distributed among Proteobacteria and Actinobacteria, particularly in Streptomyces, making available a rich resource of novel lasso peptides and enzyme machineries towards lasso topologies.

This book assembles concisely written chapters by world-leaders in the field summarizing recent advances in understanding microbial responses to hydrocarbons. Subjects treated include mechanisms of sensing, hydrocarbon tolerance and degradation as well as an overview on hydrophobic modification of biomolecules. Other chapters are dedicated to issues related to the reduced bioavailability of hydrocarbons, which differentiates this class of compounds form many others, but which of central importance to understand the ecophysiological consequences. This book should be standard literature in any laboratory working in this area.