This book provides a comprehensive overview of the cell cycle regulation and development in Alphaproteobacteria. Cell cycle and cellular differentiation are fascinating biological phenomena that are highly regulated in all organisms. In the last decades, many laboratories around the world have been investigating these processes in Alphaproteobacteria. This bacterial class comprises important bacterial species, studied by fundamental and applied research. The complexity of cell cycle regulation and many examples of cellular differentiations in this bacterial group represent the main motives of this book. The book starts with discussing the regulation of cell cycle in alphaproteobacterial species from a system biology perspective. The following chapters specifically focus on the model species Caulobacter crescentus multiple layers of regulation, from transcriptional cascades to proteolysis and dynamic subcellular regulation of cell cycle regulators. In addition, the cell division process, chromosome segregation and growth of the cell envelope is described in detail. The last part of the book covers examples of non-Caulobacter alphaproteobacterial models, such as Agrobacterium tumefaciens, Brucella species and Sinorhizobium meliloti and also discusses possible applications. This book will be of interest to researchers in microbiology and cell biology labs working on cell cycle regulation and development.
This book provides readers with an overview of the frequent occurrence of asymmetric cell division. Employing a broad range of examples, it highlights how this mode of cell division constitutes the basis of multicellular organism development and how its misregulation can lead to cancer. To underline such developmental correlations, readers will for example gain insights into stem cell fate and tumor growth. In turn, subsequent chapters include descriptions of asymmetric cell division from unicellular organisms to humans in both physiological and pathological conditions. The book also illustrates the importance of this process for evolution and our need to understand the background mechanisms, offering a valuable guide not only for students in the field of developmental biology but also for experienced researchers from neighboring fields.
Analogous to the eukaryotic G1, S and M phase of the cell cycle, the bacterial cell cycle can be classified into independent stages. Slowly growing bacterial cells undergo three different stages, B-, C- and D-phase, respectively, while the cell cycle of fast-growing bacteria involves at least two independent cycles: the chromosome replication and the cell division. The oscillation in gene expression regulated by transcription factors, and proteolysis mediated by ClpXP, are closely correlated with progression of the cell cycle. Indeed, it has been shown that DnaA couples DNA replication initiation with the expression of the two oscillating regulators GcrA and CtrA, and the DnaA/GcrA/CtrA regulatory cascade drives the forward progression of the Caulobacter cell cycle. Furthermore, it has been found that: the DnaA oscillation in Eschericha coli and Caulobacter crescentus plays an important role in the cell cycle coordination; RpoS in Coxiella regulates the gene expression involved in the developmental cycle; the SigB and SinR transcription factors control whether cells remain in or leave a biofilm responding to metabolic conditions in Bacillus subtilis; similarly, BolA in most Gram-negative bacteria turns off motility and turns on biofilm development as a transcription factor; CtrA regulates cell division and outer membrane composition of the pathogen Brucella abortus; an essential transcription factor SciP enhances robustness of Caulobacter cell cycle regulation. Interestingly, transcription factors mediated metabolism fluctuations are also related to progression of the cell cycle. It has been shown that: CggR and Cra factors are involved in the flux-signaling metabolite fructose-1,6-bisphosphate; IclR mediates para-hydroxybenzoate catabolism in Streptomyces coelicolor; CceR and AkgR regulate central carbon and energy metabolism in alphaproteobacteria; and these metabolism changes affect cell growth. In line with the argument, AspC-mediated aspartate metabolism coordinates the E. coli cell cycle. However, the molecular mechanisms of maintaining the proper cell cycle progression through coordination of transcription factors mediated gene transcription oscillation, cellular metabolism with the cell cycle are not yet well-established. This Research Topic is intended to cover the spectrum of cell cycle regulatory mechanisms, in particular the coordination of transcription factor mediated gene transcription oscillations, and the cellular metabolisms associated with the cell cycle. We welcome all types of articles including Original Research, Review, and Mini Review. The subject areas of interest include but are not limited to: 1. Cell cycle coordination through gene expression and expression oscillation mediated by transcription factors. 2. Regulation of the cell cycle by proteolysis oscillation. 3. Coordination of the cell cycle with metabolism fluctuation. 4. DNA methylation fluctuation and the cell cycle. 5. Novel transcription factors and gene expression patterns associated with the cell cycle.
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.
The broad host range pathogenic bacterium Agrobacterium tumefaciens has been widely studied as a model system to understand horizontal gene flow, secretion of effector proteins into host cells, and plant-pathogen interactions. Agrobacterium-mediated plant transformation also is the major method for generating transgenic plants for research and biotechnology purposes. Agrobacterium species have the natural ability to conduct interkingdom genetic transfer from bacteria to eukaryotes, including most plant species, yeast, fungi, and even animal cells. In nature, A. tumefaciens causes crown gall disease resulting from expression in plants of auxin and cytokinin biosynthesis genes encoded by the transferred (T-) DNA. Gene transfer from A. tumefaciens to host cells requires virulence (vir) genes that reside on the resident tumor-inducing (Ti) plasmid. In addition to T-DNA, several Virulence (Vir) effector proteins are also translocated to host cells through a bacterial type IV secretion system. These proteins aid in T-DNA trafficking through the host cell cytoplasm, nuclear targeting, and T-DNA integration. Genes within native T-DNAs can be replaced by any gene of interest, making Agrobacterium species important tools for plant research and genetic engineering. In this research topic, we provided updated information on several important areas of Agrobacterium biology and its use for biotechnology purposes.
