Download or read book Molecular Mechanisms Regulating the Timing of Initiation of DNA Replication During the Cell Division Cycle of Escherichia Coli written by Joseph A. Bogan and published by . This book was released on 1997 with total page 238 pages. Available in PDF, EPUB and Kindle. Book excerpt:
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 The Bacterial Cell Coupling between Growth Nucleoid Replication Cell Division and Shape Volume 2 written by Ariel Amir and published by Frontiers Media SA. This book was released on 2019-11-14 with total page 246 pages. Available in PDF, EPUB and Kindle. Book excerpt: The 1st volume of our Research Topic "The Bacterial Cell: Coupling between Growth, Nucleoid Replication, Cell Division and Shape” was published as an eBook in May 2016 (see: http://journal.frontiersin.org/researchtopic/2905/the-bacterial-cell-coupling-between-growth-nucleoid-replication-cell-division-and-shape). As a sign of growing interest to the topic, two workshops followed the same year: "Stochasticity in the Cell Cycle" in Jerusalem (Israel) by the Hebrew University’s Institute of Advanced Studies and EMBO's "Cell Size Regulation" in Joachimsthal (Germany). From the time of launching the first edition, several new groups have entered the field, and many established groups have made significant advances using state-of-the-art microscopy and microfluidics. Combining these approaches with the techniques pioneered by quantitative microbiologists decades ago, these approaches have provided remarkable amounts of numerical data. Most of these data needed yet to be put into a broader theoretical perspective. Moreover, the molecular mechanisms governing coordination and progression of the main bacterial cell cycle processes have remained largely unknown. These outstanding fundamental questions and the growing interest to the field motivated us to launch the next volume titled “The Bacterial Cell: Coupling between Growth, Nucleoid Replication, Cell Division, and Shape, Volume 2” shortly after completion of the first edition in October 2016. The issue contains 17 contributions from a diverse array of scientists whose field of study spans microbiology, biochemistry, genetics, experimental and theoretical biophysics. The specific questions addressed in the issue include: What triggers initiation of chromosome replication? How is cell division coordinated with replication both spatially and temporally? How is cell size controlled and linked to the rate of mass growth? What role plays physical organization of the chromosomes in their segregation and in regulation of cell division? The publications covering these questions are divided into three topical areas: 1) Cell Cycle Regulation, 2) Growth and Division, and 3) Nucleoid Structure and Replication. New ideas and techniques put forward in these articles bring us closer to understand these fundamental cellular processes, but the quest to resolve them is far from being complete. Plans for the next edition are under way along with further meetings and workshops, e.g., an EMBO Workshop on Bacterial cell biophysics: DNA replication, growth, division, size and shape in Ein Gedi (Israel), May 2020. We hope that via such interdisciplinary exchange of ideas we will come closer to answering the above-mentioned complex and multifaceted questions.
Download or read book The Cell Cycle written by G. M. Padilla and published by Academic Press. This book was released on 2013-09-11 with total page 420 pages. Available in PDF, EPUB and Kindle. Book excerpt: The Cell Cycle: Gene Enzyme Interactions presents the primary regulatory mechanisms of the cell cycle. This book provides theoretical and methodological discussions concerning cell cycles. Organized into 17 chapters, this book begins with an overview of cell evolution and thermodynamics. This text then examines the regulation of initiation of chromosome replication, and the coordination between this event and cell division, in Escherichia coli. Other chapters consider the operon model for the control of genetic expression in bacterial cells, which provides an understanding of the regulatory mechanisms of gene function. This book discusses as well the observations and experiments on the timing of events in the cell cycles of some bacteria and attempts to provide explanations in terms of established control systems. The final chapter deals with DNA markers, which serve as a convenient starting point for exploring the general principles of cell cycle markers. This book is a valuable resource for cell biologists.
Download or read book The Bacterial Cell Coupling between Growth Nucleoid Replication Cell Division and Shape written by Arieh Zaritsky and published by Frontiers Media SA. This book was released on 2016-05-02 with total page 326 pages. Available in PDF, EPUB and Kindle. Book excerpt: Bacterial Physiology was inaugurated as a discipline by the seminal research of Maaløe, Schaechter and Kjeldgaard published in 1958. Their work clarified the relationship between cell composition and growth rate and led to unravel the temporal coupling between chromosome replication and the subsequent cell division by Helmstetter et al. a decade later. Now, after half a century this field has become a major research direction that attracts interest of many scientists from different disciplines. The outstanding question how the most basic cellular processes - mass growth, chromosome replication and cell division - are inter-coordinated in both space and time is still unresolved at the molecular level. Several particularly pertinent questions that are intensively studied follow: (a) what is the primary signal to place the Z-ring precisely between the two replicating and segregating nucleoids? (b) Is this coupling related to the structure and position of the nucleoid itself? (c) How does a bacterium determine and maintain its shape and dimensions? Possible answers include gene expression-based mechanisms, self-organization of protein assemblies and physical principles such as micro-phase separations by excluded volume interactions, diffusion ratchets and membrane stress or curvature. The relationships between biochemical reactions and physical forces are yet to be conceived and discovered. This e-book discusses the above mentioned and related questions. The book also serves as an important depository for state-of-the-art technologies, methods, theoretical simulations and innovative ideas and hypotheses for future testing. Integrating the information gained from various angles will likely help decipher how a relatively simple cell such as a bacterium incorporates its multitude of pathways and processes into a highly efficient self-organized system. The knowledge may be helpful in the ambition to artificially reconstruct a simple living system and to develop new antibacterial drugs.
Download or read book Studies of Mechanisms Involved in Coordinating Cell Growth and Genomic Duplication written by and published by . This book was released on 1993 with total page 132 pages. Available in PDF, EPUB and Kindle. Book excerpt: In the bacterium, Escherichia coli, the processes controlling the conversion of a mother cell into daughter cells, cell growth, DNA replication, and cell division, are highly coordinated; more than 99.97% of daughter cells successfully receive DNA. The rate of initiation at the origin of replication, oriC, controls the rate of replication in prokaryotic cells. Therefore, the coupling of replication to cell growth requires that the frequency of initiation from oriC be a function of growth rate. One method of controlling interinitiation time may be the state of methylation of GATC sites in or near oriC and in the dnaA promoter region. We examined the effect of removal of a protein methylation blocking factor, which has previously been shown to delay methylation of GATC sites, and found no effect on timing of initiation. Other elements, DnaA concentration and transcription from promoters adjacent to oriC, which may also be necessary for correct timing of DNA replication, are under stringent control. During amino acid starvation, the product of the relA gene, ppGpp synthetase I, synthesizes guanosine tetraphosphate (ppGpp), and concomitant with the increase in ppGpp, various physiological reactions occur in what is known as the stringent response. The nucleotide ppGpp is found in concentrations inversely proportional to growth rate, suggesting ppGpp may act as an effector molecule coupling growth rate with various cellular processes including initiation of DNA replication. We determined that relA overexpression, and thus ppGpp overexpression, causes a drastic inhibition of protein synthesis, which inhibits initiation of replication, and inhibits the accumulation of the carbon source glycerol into the cell. Cells that exhibit an abnormal number of chromosomes following completion of ongoing rounds of DNA replication have been believed to result from incorrect timing of initiation in the cell cycle. Cells deficient in RecA protein have this phenotype, but initiate DNA replication at the proper time in the cell cycle. We discovered that RecA protein is not required for correct timing of initiation of DNA replication, but instead is necessary for equal partitioning of the chromosome into daughter cells.
Download or read book Perspectives in Cellular Regulation written by Judith Campisi and published by . This book was released on 1991-06-06 with total page 384 pages. Available in PDF, EPUB and Kindle. Book excerpt: Provides excellent overviews highlighting the research results of leading scientists as well as young investigators in the field of cellular and molecular regulatory mechanisms. How each cell grows and develops at the appropriate time and place is thoroughly covered along with such issues as culturing the types of cells which represent excellent model systems for studies on tumor formation, proliferation and differentiation; cell cycle control; molecular control of DNA replication and repair and much more.
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 The Circadian Clock written by Urs Albrecht and published by Springer Science & Business Media. This book was released on 2010-01-23 with total page 306 pages. Available in PDF, EPUB and Kindle. Book excerpt: With the invitation to edit this volume, I wanted to take the opportunity to assemble reviews on different aspects of circadian clocks and rhythms. Although most c- tributions in this volume focus on mammalian circadian clocks, the historical int- duction and comparative clocks section illustrate the importance of various other organisms in deciphering the mechanisms and principles of circadian biology. Circadian rhythms have been studied for centuries, but only recently, a mole- lar understanding of this process has emerged. This has taken research on circadian clocks from mystic phenomenology to a mechanistic level; chains of molecular events can describe phenomena with remarkable accuracy. Nevertheless, current models of the functioning of circadian clocks are still rudimentary. This is not due to the faultiness of discovered mechanisms, but due to the lack of undiscovered processes involved in contributing to circadian rhythmicity. We know for example, that the general circadian mechanism is not regulated equally in all tissues of m- mals. Hence, a lot still needs to be discovered to get a full understanding of cir- dian rhythms at the systems level. In this respect, technology has advanced at high speed in the last years and provided us with data illustrating the sheer complexity of regulation of physiological processes in organisms. To handle this information, computer aided integration of the results is of utmost importance in order to d- cover novel concepts that ultimately need to be tested experimentally.
Download or read book Failsafe Mechanisms Coordinate Cell Division and the Initiation of DNA Replication in Bacteria written by Heidi Ann Arjes and published by . This book was released on 2014 with total page 177 pages. Available in PDF, EPUB and Kindle. Book excerpt: During the cell cycle, a cell must replicate its DNA, segregate the genome and divide into two identical daughter cells with full chromosomes. This process needs to be specifically coordinated to ensure that cell division does not occur before DNA replication has finished and that the cell septates precisely at midcell to segregate one chromosome to each daughter cell. If cells divide before the chromosome is fully replicated, the chromosome could be guillotined or cell division could occur resulting in cells without chromosomes. If division does not occur properly, the cells elongate but do not divide and form multinucleate filaments. In wild-type cells, DNA replication and cell division appear to be perfectly coordinated. Even at faster doubling times, the cell cycle is synchronized so that DNA replication initiates and terminates once per cell division, the cell division protein FtsZ assembles into a ring precisely at midcell, and cell septation only occurs once the chromosome has replicated and segregated. Despite this apparent coordination, the long-held view in the field is that cell division and DNA replication are independent cycles that are merely coordinated during normal growth. However, it remains widely accepted that cell division is independent from DNA replication in bacteria. In this dissertation, I make 3 contributions to the field of cell cycle regulation. First, I identify a control point that couples cell division with the initiation of DNA replication. Second, I show that long-term inhibitions of cell division lead to terminal cell cycle arrest at a time we have termed the "Point of no return" or PONR. The PONR is equivalent to the eukaryotic G0 arrest and validates the development of antibiotics that target the cell division machinery. Third, I characterized determinants for assembly of the tubulin-like protein FtsZ using a genetic approach. This work enhances our understanding of what is critical for FtsZ function in vivo and highlights the need to develop better assays for evaluating FtsZ assembly in vitro.
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 Regulation of Chromosomal DNA Replication in Escherichia Coli written by Lyle Adair Simmons and published by . This book was released on 2003 with total page 464 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Studies of Mechanisms Involved in Coordinating Cell Growth and Genomic Duplication written by Amy Louise Svitil and published by . This book was released on 1993 with total page 170 pages. Available in PDF, EPUB and Kindle. Book excerpt: In the bacterium, Escherichia coli, the processes controlling the conversion of a mother cell into daughter cells, cell growth, DNA replication, and cell division, are highly coordinated; more than 99.97% of daughter cells successfully receive DNA. The rate of initiation at the origin of replication, oriC, controls the rate of replication in prokaryotic cells. Therefore, the coupling of replication to cell growth requires that the frequency of initiation from oriC be a function of growth rate. One method of controlling interinitiation time may be the state of methylation of GATC sites in or near oriC and in the dnaA promoter region. We examined the effect of removal of a protein methylation blocking factor, which has previously been shown to delay methylation of GATC sites, and found no effect on timing of initiation. Other elements, DnaA concentration and transcription from promoters adjacent to oriC, which may also be necessary for correct timing of DNA replication, are under stringent control. During amino acid starvation, the product of the relA gene, ppGpp synthetase I, synthesizes guanosine tetraphosphate (ppGpp), and concomitant with the increase in ppGpp, various physiological reactions occur in what is known as the stringent response. The nucleotide ppGpp is found in concentrations inversely proportional to growth rate, suggesting ppGpp may act as an effector molecule coupling growth rate with various cellular processes including initiation of DNA replication. We determined that relA overexpression, and thus ppGpp overexpression, causes a drastic inhibition of protein synthesis, which inhibits initiation of replication, and inhibits the accumulation of the carbon source glycerol into the cell. Cells that exhibit an abnormal number of chromosomes following completion of ongoing rounds of DNA replication have been believed to result from incorrect timing of initiation in the cell cycle. Cells deficient in RecA protein have this phenotype, but initiate DNA replication at the proper time in the cell cycle. We discovered that RecA protein is not required for correct timing of initiation of DNA replication, but instead is necessary for equal partitioning of the chromosome into daughter cells.
Download or read book Completion of DNA Replication in Escherichia Coli written by and published by . This book was released on 2018 with total page 165 pages. Available in PDF, EPUB and Kindle. Book excerpt: To maintain genomic integrity, all cells must accurately duplicate their genetic material in order to provide intact and complete copies to each daughter cell following cell division. Successful inheritance of chromosomal information without changing even a single nucleotide requires accurate and robust DNA replication. This requires that cells tightly control replication initiation from the origin(s), processive elongation of the replisome, and the completion of DNA replication by resolving convergent replication forks ensuring that each sequence is duplicated without alteration. Unlike initiation and elongation, the process by which replication forks converge and are resolved into two discrete, inheritable DNA molecules is not well understood. This process must be remarkably efficient, occurring thousands of times per cell division in human cells, and is likely to be a fundamental step in regulating genome stability in all cells. In this dissertation I address how DNA replication completes in the model system Escherichia coli. To achieve this, I examined candidate mutants for impairments in the completion of DNA replication. By evaluating growth, viability, chromosomal copy number, and plasmid stability I identified a requirement for the proteins RecBCD, ExoI, and SbcCD in the completion reaction. SbcCD and ExoI act before RecBCD in the completion reaction and process the DNA intermediates arising as replication forks converge. These enzymes act in the completion reaction without recombination or RecA, but in the absence of the normal process recombination is required to complete DNA replication via an aberrant pathway that results in genomic instability.
Download or read book Initiation of the DNA Replication Cycle in Escherichia Coli written by Gretchen Herpel Stein and published by . This book was released on 1971 with total page 240 pages. Available in PDF, EPUB and Kindle. Book excerpt:
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 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.
