Download or read book DNA Replication and Cell Size Control in Escherichia Coli written by Dongyang Li and published by . This book was released on 2018 with total page 178 pages. Available in PDF, EPUB and Kindle. Book excerpt: The defining feature of living organisms is their capacity to reproduce and pass on the genetic information so that their progeny can flourish. For bacteria, reproduction is a feat by itself--Escherichia coli cells cultured in optimal conditions grow rapidly and divide about every 20 minutes. In other words, the cell has to replicate all cellular contents, and be ready to divide evenly into two daughter cells within this 20 minutes. Biosynthesis of new cellular materials, e.g. proteins, nucleic acis, lipids and other metabolites accumulate and roughly doubles after every generation. Notably, the deoxyribonucleic acid (DNA) encodes genetic informationand needs to be duplicated in order to faithfully pass on this information to the progeny. This process of DNA replication in the cell needs to dynamically adapt to fluctuation in growth condition and cellular physiology. Such coordination is controlled at the first step of replcation--the initiation of replication. In this thesis, I presented the development of methods for measuring DNA replication duration (replication period), the quantitative relationship between DNA replication and cell size as well as the mechanism of replication initiation. DNA replication measurement laid the foundation of studying the quantitative relationship between cell size and DNA replication. A general growth law was proposed to describe cell size regulation in light of three physiological variables including biosynthesis rate, cell cycle progression and replicaiton initiation. Of the three variables, the mass when cell initiates replication (initiation mass) remains invariant despite a wide spectrum of antibiotics or growth limitation challenge. This invariant initiation mass called into question about the mechanism of initiation to achieve such constancy. We proposed a simple threshold model to explain how cells can maintain a invariant initiation mass by regulating the expression of initiation regulators (initiators). The initiation mass is inversely proportional to the initiator levels, which is held constant. Experimental evidence was provided to test our model prediction.

Download or read book The Relationship Between Size Growth Rate and the Cell Cycle in Bacteria written by Norbert Seabrook Hill and published by . This book was released on 2013 with total page 228 pages. Available in PDF, EPUB and Kindle. Book excerpt: DNA replication, nucleoid segregation, and cell division must be coordinated with growth and cell size to ensure viability in all organisms. Failure to do so yields progeny with an inappropriate fraction of genetic and cytosolic material, reducing the fitness of the organism. This dissertation has sought to understand the role of cell size in two fundamental aspects of bacterial physiology: 1) How do bacteria regulate cell size in response to nutrient availability? 2) Does cell size govern progression of the cell cycle? Growth rate and nutrient availability are primary determinants of cell size in single-celled organisms. Bacterial cells cultured in nutrient-rich circumstances are twice the size of cells grown in nutrient-poor conditions. How bacteria are able to perceive nutrient levels and amend cell size is largely undefined. In Chapter 2, I report the identification and characterization of the glucosyltransferase OpgH as a uridine diphosphate (UDP) glucose-dependent effector that coordinates Escherichia coli cell size with growth rate and nutritional status. High intracellular levels of UDP-glucose accumulate during growth in nutrient-rich conditions. In turn, UDP-glucose activates OpgH to sequester the essential division protein FtsZ, which obstructs assembly and/or maturation of the cytokinetic ring, delaying division to increase cell size. In this way, OpgH directly gauges nutrient status and modifies cell size through the timing of division. Cell cycle progression is regulated by cell size in all organisms. In bacteria, it has long been postulated that the achievement of a particular cell size triggers chromosomal replication. Chapter 3 of this dissertation describes a comparative study between E. coli and Bacillus subtilis examining whether cell mass determines the timing of initiation of DNA replication. Using mutants defective for cell size, my data confirms that E. coli directly ties the initiation event to cell mass. However, counter to the paradigm, the phenomenon of initiation mass is not conserved to B. subtilis, which appears to coordinate DNA replication through a cell cycle timer device. This dissertation yields several original conclusions. First, the discovery of OpgH as a UDP-glucose-activated antagonist of FtsZ polymerization is a significant advance in the understanding of cell size control in bacteria. However, these results in tandem with the cognate pathway in B. subtilis reveal a remarkable instance of convergent evolution. Based on this, I propose that UDP-glucose and cognate UDP-glucose binding proteins are a widely conserved strategy to direct nutrient-dependent changes in cell size. In addition, the revelation that initiation of DNA replication is cell size-independent in B. subtilis adds to a growing sentiment that mechanisms controlling DNA replication are fundamentally divergent throughout bacteria.

Download or read book Control of Macromolecular Synthesis written by Ole Maaløe and published by . This book was released on 1966 with total page 306 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Size Limits of Very Small Microorganisms written by National Research Council and published by National Academies Press. This book was released on 1999-10-13 with total page 171 pages. Available in PDF, EPUB and Kindle. Book excerpt: How small can a free-living organism be? On the surface, this question is straightforward-in principle, the smallest cells can be identified and measured. But understanding what factors determine this lower limit, and addressing the host of other questions that follow on from this knowledge, require a fundamental understanding of the chemistry and ecology of cellular life. The recent report of evidence for life in a martian meteorite and the prospect of searching for biological signatures in intelligently chosen samples from Mars and elsewhere bring a new immediacy to such questions. How do we recognize the morphological or chemical remnants of life in rocks deposited 4 billion years ago on another planet? Are the empirical limits on cell size identified by observation on Earth applicable to life wherever it may occur, or is minimum size a function of the particular chemistry of an individual planetary surface? These questions formed the focus of a workshop on the size limits of very small organisms, organized by the Steering .Group for the Workshop on Size Limits of Very Small Microorganisms and held on October 22 and 23, 1998. Eighteen invited panelists, representing fields ranging from cell biology and molecular genetics to paleontology and mineralogy, joined with an almost equal number of other participants in a wide-ranging exploration of minimum cell size and the challenge of interpreting micro- and nano-scale features of sedimentary rocks found on Earth or elsewhere in the solar system. This document contains the proceedings of that workshop. It includes position papers presented by the individual panelists, arranged by panel, along with a summary, for each of the four sessions, of extensive roundtable discussions that involved the panelists as well as other workshop participants.

Download or read book Molecular Biology of the Cell written by and published by . This book was released on 2002 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book DNA Replication Control in Microbial Cell Factories written by Monika Glinkowska and published by Springer. This book was released on 2014-09-23 with total page 56 pages. Available in PDF, EPUB and Kindle. Book excerpt: This work describes the current knowledge of biochemical mechanisms regulating initiation of DNA replication in Escherichia coli, which focuses on the control of activity of the DnaA protein. Examples of direct linkages between DNA replication and other cellular processes are provided. In addition, similarities of the mechanisms of regulation of DNA replication operating in prokaryotic and eukaryotic cells are identified, and implications for understanding more complex processes, like carcinogenesis are suggested. Studies of recent years provided evidence that regulation of DNA replication in bacteria is more complex than previously anticipated. Multiple layers of control seem to ensure coordination of this process with the increase of cellular mass and the division cycle. Metabolic processes and membrane composition may serve as points where integration of genome replication with growth conditions occurs. It is also likely that coupling of DNA synthesis with cellular metabolism may involve interactions of replication proteins with other macromolecular complexes, responsible for various cellular processes. Thus, the exact set of factors participating in triggering the replication initiation may differ depending on growth conditions. Therefore, understanding the regulation of DNA duplication requires placing this process in the context of the current knowledge on bacterial metabolism, as well as cellular and chromosomal structure. Moreover, in both Escherichia coli and eukaryotic cells, replication initiator proteins were shown to play other roles in addition to driving the assembly of replication complexes, which constitutes another, yet not sufficiently understood, layer of coordinating DNA replication with the cell cycle.

Download or read book The Biology of the Cell Cycle written by J. M. Mitchison and published by CUP Archive. This book was released on 1971-11-30 with total page 324 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Growth Rate Regulation and Control of Initiation of DNA Replication in Escherichia Coli written by Anne Eliane Chiaramello and published by . This book was released on 1990 with total page 300 pages. Available in PDF, EPUB and Kindle. Book excerpt: The initiation of DNA synthesis at the chromosomal replication origin, oriC, in Escherichia coli involves an RNA polymerase-mediated step. The level of synthesis of transcripts moving counterclockwise toward oriC is controlled at two promoters, P1 (asnC) and P2 (mioC), and at two transcription terminator regions, T1 and T2. As shown by S1 mapping, termination at the T2 region occurs to the right of oriC at nucleotides 297-299 and 306-310, while major termination events in the T1 region occur in and near the mioC promoter. The majority of transcripts entering oriC originates from the mioC promoter. Transcription from the mioC promoter has been shown to enhance the frequency of initiation of DNA replication of oriC containing plasmids, and to stabilize these plasmids in the host cells. The mioC promoter, which is stringently controlled, is also growth rate regulated. The amount of mioC transcripts relative to the amount of total RNA was inversely correlated with growth rate. This transcript is characterized by a short half-life (1.5 min). The mioC promoter, which contains a DnaA protein binding site, was much less susceptible to repression by DnaA protein when located in the chromosome, than when located in a plasmid. Only a very high concentration of DnaA protein repressed the mioC promoter. The DnaA protein, which is required for initiation of DNA replication from oriC, is growth rate regulated. As shown by RNase protection, this regulation is exerted at the transcriptional level, affecting both promoters, dnaAp1 and dnaAp2. Transcription from these two promoters is also stringently controlled. The amount of DnaA protein in spoT mutants, which are deficient in ppGpp pyrophosphorylase activity, decreases as the severity in the mutation increases. Thus, the intracellular concentration of ppGpp influences the expression of the dnaA gene. In conclusion, the growth rate regulation and stringent control of the dnaA gene suggest that one way in which DNA replication is coordinated with the growth rate is via ppGpp synthesis at the ribosome.

Download or read book Prokaryotic Cytoskeletons written by Jan Löwe and published by Springer. This book was released on 2017-05-11 with total page 457 pages. Available in PDF, EPUB and Kindle. Book excerpt: 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.

Download or read book Bacterial Growth and Division written by Stephen Cooper and published by Elsevier. This book was released on 2012-12-02 with total page 528 pages. Available in PDF, EPUB and Kindle. Book excerpt: How does a bacterial cell grow during the division cycle? This question is answered by the codeveloper of the Cooper-Helmstetter model of DNA replication. In a unique analysis of the bacterial division cycle, Cooper considers the major cell categories (cytoplasm, DNA, and cell surface) and presents a lucid description of bacterial growth during the division cycle. The concepts of bacterial physiology from Ole Maaløe's Copenhagen school are presented throughout the book and are applied to such topics as the origin of variability, the pattern of DNA segregation, and the principles underlying growth transitions. The results of research on E. coli are used to explain the division cycles of Caulobacter, Bacilli, Streptococci, and eukaryotes. Insightful reanalysis highlights significant similarities between these cells and E.coli. With over 25 years of experience in the study of the bacterial division cycle, Cooper has synthesized his ideas and research into an exciting presentation. He manages to write a comprehensive volume that will be of great interest to microbiologists, cell physiologists, cell and molecular biologists, researchers in cell-cycle studies, and mathematicians and engineering scientists interested in modeling cell growth. - Written by one of the codiscoverers of the Cooper-Helmstetter model - Applies the results of research on E. coli to other groups, including Caulobacter, Bacilli, Streptococci, and eukaryotes; the Caulobacter reanalysis highlights significant similarities with the E. coli system - Presents a unified description of the bacterial division cycle with relevance to eukaryotic systems - Addresses the concepts of the Copenhagen School in a new and original way

Download or read book Systems Biology and Biotechnology of Escherichia coli written by Sang Yup Lee and published by Springer Science & Business Media. This book was released on 2009-03-20 with total page 471 pages. Available in PDF, EPUB and Kindle. Book excerpt: Systems biology is changing the way biological systems are studied by allowing us to examine the cell and organism as a whole. Systems biotechnology allows optimal design and development of upstream to downstream bioprocesses by taking a systems-approach. E. coli has been a model organism for almost all biological and biotechnological studies. This book brings together for the first time the state-of-the-art reviews by the world-leading experts on systems biology and biotechnological applications of E. coli. The topics covered include genomics and functional genomics, resources for systems biology, network analysis, genome-scale metabolic reconstruction, modelling and simulation, dynamic modelling and simulation, systems-level analysis of evolution, plasmids and expression systems, protein synthesis, production and export, engineering the central metabolism, synthetic biology, and systems metabolic engineering of E. coli. This book provides readers with guidance on how a complex biological system can be studied using E. coli as a model organism. It also presents how to perform synthetic biology and systems metabolic engineering studies on E. coli with successful examples, the approaches of which can be extended to other organisms. This book will be a complete resource for anyone interested in systems biology and biotechnology.

Download or read book Transport Equations in Biology written by Benoît Perthame and published by Springer Science & Business Media. This book was released on 2006-12-14 with total page 206 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book presents models written as partial differential equations and originating from various questions in population biology, such as physiologically structured equations, adaptive dynamics, and bacterial movement. Its purpose is to derive appropriate mathematical tools and qualitative properties of the solutions. The book further contains many original PDE problems originating in biosciences.

Download or read book Initiation of DNA Replication in Escherichia Coli written by Michael Dalbey and published by . This book was released on 1975 with total page 378 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Cell Biology by the Numbers written by Ron Milo and published by Garland Science. This book was released on 2015-12-07 with total page 400 pages. Available in PDF, EPUB and Kindle. Book excerpt: A Top 25 CHOICE 2016 Title, and recipient of the CHOICE Outstanding Academic Title (OAT) Award. How much energy is released in ATP hydrolysis? How many mRNAs are in a cell? How genetically similar are two random people? What is faster, transcription or translation?Cell Biology by the Numbers explores these questions and dozens of others provid

Download or read book Molecular Cytology of Escherichia Coli written by Nanne Nanninga and published by . This book was released on 1985 with total page 352 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Two component Signal Transduction written by James A. Hoch and published by Amer Society for Microbiology. This book was released on 1995 with total page 488 pages. Available in PDF, EPUB and Kindle. Book excerpt: 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.

Download or read book Duplication of Escherichia Coli written by Ludovicus Johannes Hubertus Koppes and published by . This book was released on 1980 with total page 144 pages. Available in PDF, EPUB and Kindle. Book excerpt: