Cell Cycle Regulation and Development in Alphaproteobacteria


Book Description

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.




Prokaryotic Cytoskeletons


Book Description

This book describes the structures and functions of active protein filaments, found in bacteria and archaea, and now known to perform crucial roles in cell division and intra-cellular motility, as well as being essential for controlling cell shape and growth. These roles are possible because the cytoskeletal and cytomotive filaments provide long range order from small subunits. Studies of these filaments are therefore of central importance to understanding prokaryotic cell biology. The wide variation in subunit and polymer structure and its relationship with the range of functions also provide important insights into cell evolution, including the emergence of eukaryotic cells. Individual chapters, written by leading researchers, review the great advances made in the past 20-25 years, and still ongoing, to discover the architectures, dynamics and roles of filaments found in relevant model organisms. Others describe one of the families of dynamic filaments found in many species. The most common types of filament are deeply related to eukaryotic cytoskeletal proteins, notably actin and tubulin that polymerise and depolymerise under the control of nucleotide hydrolysis. Related systems are found to perform a variety of roles, depending on the organisms. Surprisingly, prokaryotes all lack the molecular motors associated with eukaryotic F-actin and microtubules. Archaea, but not bacteria, also have active filaments related to the eukaryotic ESCRT system. Non-dynamic fibres, including intermediate filament-like structures, are known to occur in some bacteria.. Details of known filament structures are discussed and related to what has been established about their molecular mechanisms, including current controversies. The final chapter covers the use of some of these dynamic filaments in Systems Biology research. The level of information in all chapters is suitable both for active researchers and for advanced students in courses involving bacterial or archaeal physiology, molecular microbiology, structural cell biology, molecular motility or evolution. Chapter 3 of this book is open access under a CC BY 4.0 license.




Analysis of an Uncharacterized Gene in Caulobacter Crescentus and Its Novel Connections with Cell Cycle Regulatory Machinery


Book Description

Cell division and differentiation are complex biological phenomena that occur in all kingdoms of life. Understanding the molecular mechanisms that underlie these complex processes often requires the study of experimentally tractable model organisms. As a Gram-negative bacteria with less than four thousand genes, Caulobacter crescentus exhibits cell differentiation, highly regulated chromosome replication and segregation, and asymmetric cell division with every turn of the cell cycle. To achieve these behaviors, Caulobacter utilizes spatial control mechanisms such as sub-cellular compartmentalization and protein localization. The cell poles are particularly enriched for cell cycle regulatory proteins. Many of these proteins are localized by the hub protein PopZ, which forms a three-dimensional scaffold that also aids in chromosome segregation. The PopZ scaffold also includes proteolysis activity, which regulates cell cycle progression in a manner that is analogous to well-known eukaryotic systems. In this dissertation, I characterized an evolutionarily conserved protein of unknown function, which is now named SpbR (Swarmer pole blocking factoR). SpbR is a pole-localized protein that has co-evolved with PopZ and other polar proteins. Strikingly, SpbR over-production exhibited a severe chromosome segregation phenotype, in which the newly replicated centromere failed to travel across the cell to its normal destination at the opposite pole. SpbR overproduction results in its accumulation at the old pole, where it physically interacts with PopZ. This prevents the relocation of PopZ to the new pole, thereby eliminating a positional cue for centromere translocation. Consistent with this, the centromere translocation phenotype of SpbR overproducing cells is further enhanced in genetic backgrounds that accumulate higher SpbR or reduce chromosome segregation activity. We find that pole-localized SpbR is normally cleared by proteolysis before the time of chromosome segregation, indicating that SpbR turnover is part of the cell cycle-dependent program of polar development.




Two-component Signal Transduction


Book Description

The human enteroviruses, particularly the polio viruses, have had a significant role in the history of medicine and microbiology; and continue to cause clinical problems, as well as provide targets for molecular investigation. This book offers a link between the basic science and clinical medicine.







Cell Biology of Bacteria


Book Description

Often thought to lack signifucant internal organization by comparison with eukaryotic cells, prokaryotes have in face been shown to possess distinct intracellular compartments. The book covers all aspects of prokaryotic cell biology, including the bacterial cytoskeleton, membrance organization, chromosome dynamics, nucleic acid processing and dynamics, as well as various methods.




Bacterial Chromatin


Book Description




Dyneins


Book Description

Research on dyneins has a direct impact on human diseases, such as viruses and cancer. With an accompanying website showing over 100 streaming videos of cell dynamic behavior for best comprehension of material, Dynein: Structure, Biology and Disease is the only reference covering the structure, biology and application of dynein research to human disease. From bench to bedside, Dynein: Structure, Biology and Disease offers research on fundamental cellular processes to researchers and clinicians across developmental biology, cell biology, molecular biology, biophysics, biomedicine, genetics and medicine. Broad-based up-to-date resource for the dynein class of molecular motors Chapters written by world experts in their topics Numerous well-illustrated figures and tables included to complement the text, imparting comprehensive information on dynein composition, interactions, and other fundamental features




Mechanisms of Mitotic Chromosome Segregation


Book Description

This book is a printed edition of the Special Issue "Mechanisms of Mitotic Chromosome Segregation" that was published in Biology