Host Growth Rate Affects Bacteriophage Lambda Burst Size
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A Viewpoint of Aspects of a History of Genetics: an Autobiography
12. The Postgraduate Medical School,London University. The Head of the Bacteriology Department at the PGMS(later the Royal PGMS) was Professor Lord(Trevor) Stamp who did'nt seem to bother what research I did so long as I did something. My closest colleague was Dr.Denny Mitchison(Lecturer),one of the three biologist sons of authoress Naomi Mitchison and nephew of J.B.S.Haldane,whose main interest was typing tubercle bacilli under MRC!auspices. In addition there were at least two non-tenured medical graduates on the staff. My only departmental responsibilities were to take my turn at clinical bacteriology which amounted to the mornings of one week in every three or four,and to share in teaching the bacteriology course for the Diploma in Clinical Pathology which occupied me for not more than a few weeks in the year. There was,in fact,a positive obligation to spend at least half one's time at research. I decided to return to the mechanism of somatic phase variation in S.enteritidis,but had begun to realise the potentiafities of genetic analysis inherent in the recent discovery by Lederberg and Tatum(1946) of conjugation in Escherichia coli ,and wondered if Salmonella also could conjugate. But it was clear that I should first become acquainted with the phenomenon in --E.coli. Towards the end of 1950 I went on a bacterial chemistry course at Cambridge,organized by Prof.E.H.Gale,and there met Luca Cavalli(later Cavalli-Sforza) who had worked with Joshua Lederberg on conjugation at Wisconsin and,being mainly interested in population genetics,was currently a visitor in Prof.R.A.Fisher's Department of Mathematics. -
Phage Integration and Chromosome Structure. a Personal History
ANRV329-GE41-01 ARI 2 November 2007 12:22 by Annual Reviews on 12/13/07. For personal use only. Annu. Rev. Genet. 2007.41:1-11. Downloaded from arjournals.annualreviews.org ANRV329-GE41-01 ARI 2 November 2007 12:22 Phage Integration and Chromosome Structure. A Personal History Allan Campbell Department of Biological Sciences, Stanford University, Stanford, California 94305-5020; email: [email protected] Annu. Rev. Genet. 2007. 41:1–11 Key Words First published online as a Review in Advance on lysogeny, transduction, conditional lethals, deletion mapping April 27, 2007 Abstract by Annual Reviews on 12/13/07. For personal use only. The Annual Review of Genetics is online at http://genet.annualreviews.org In 1962, I proposed a model for integration of λ prophage into the This article’s doi: bacterial chromosome. The model postulated two steps (i ) circular- 10.1146/annurev.genet.41.110306.130240 ization of the linear DNA molecule that had been injected into the Annu. Rev. Genet. 2007.41:1-11. Downloaded from arjournals.annualreviews.org Copyright c 2007 by Annual Reviews. cell from the phage particle; (ii ) reciprocal recombination between All rights reserved phage and bacterial DNA at specific sites on both partners. This 0066-4197/07/1201-0001$20.00 resulted in a cyclic permutation of gene order going from phage to prophage. This contrasted with integration models current at the time, which postulated that the prophage was not inserted into the continuity of the chromosome but rather laterally attached or synapsed with it. This chapter summarizes some of the steps leading up to the model including especially the genetic characterization of specialized transducing phages (λgal ) by recombinational rescue of conditionally lethal mutations. -
P1 Bacteriophage and Tol System Mutants
P1 BACTERIOPHAGE AND TOL SYSTEM MUTANTS Cari L. Smerk A Thesis Submitted to the Graduate College of Bowling Green State University in partial fulfillment of the requirements for the degree of MASTER OF SCIENCE August 2007 Committee: Ray A. Larsen, Advisor Tami C. Steveson Paul A. Moore Lee A. Meserve ii ABSTRACT Dr. Ray A. Larsen, Advisor The integrity of the outer membrane of Gram negative bacteria is dependent upon proteins of the Tol system, which transduce cytoplasmic-membrane derived energy to as yet unidentified outer membrane targets (Vianney et al., 1996). Mutations affecting the Tol system of Escherichia coli render the cells resistant to a bacteriophage called P1 by blocking the phage maturation process in some way. This does not involve outer membrane interactions, as a mutant in the energy transucer (TolA) retained wild type levels of phage sensitivity. Conversely, mutations affecting the energy harvesting complex component, TolQ, were resistant to lysis by bacteriophage P1. Further characterization of specific Tol system mutants suggested that phage maturation was not coupled to energy transduction, nor to infection of the cells by the phage. Quantification of the number of phage produced by strains lacking this protein also suggests that the maturation of P1 phage requires conditions influenced by TolQ. This study aims to identify the role that the TolQ protein plays in the phage maturation process. Strains of cells were inoculated with bacteriophage P1 and the resulting production by the phage of viable progeny were determined using one step growth curves (Ellis and Delbruck, 1938). Strains that were lacking the TolQ protein rendered P1 unable to produce the characteristic burst of progeny phage after a single generation of phage. -
Protists and the Wild, Wild West of Gene Expression
MI70CH09-Keeling ARI 3 August 2016 18:22 ANNUAL REVIEWS Further Click here to view this article's online features: • Download figures as PPT slides • Navigate linked references • Download citations Protists and the Wild, Wild • Explore related articles • Search keywords West of Gene Expression: New Frontiers, Lawlessness, and Misfits David Roy Smith1 and Patrick J. Keeling2 1Department of Biology, University of Western Ontario, London, Ontario, Canada N6A 5B7; email: [email protected] 2Canadian Institute for Advanced Research, Department of Botany, University of British Columbia, Vancouver, British Columbia, Canada V6T 1Z4; email: [email protected] Annu. Rev. Microbiol. 2016. 70:161–78 Keywords First published online as a Review in Advance on constructive neutral evolution, mitochondrial transcription, plastid June 17, 2016 transcription, posttranscriptional processing, RNA editing, trans-splicing The Annual Review of Microbiology is online at micro.annualreviews.org Abstract This article’s doi: The DNA double helix has been called one of life’s most elegant structures, 10.1146/annurev-micro-102215-095448 largely because of its universality, simplicity, and symmetry. The expression Annu. Rev. Microbiol. 2016.70:161-178. Downloaded from www.annualreviews.org Copyright c 2016 by Annual Reviews. Access provided by University of British Columbia on 09/24/17. For personal use only. of information encoded within DNA, however, can be far from simple or All rights reserved symmetric and is sometimes surprisingly variable, convoluted, and wantonly inefficient. Although exceptions to the rules exist in certain model systems, the true extent to which life has stretched the limits of gene expression is made clear by nonmodel systems, particularly protists (microbial eukary- otes). -
|||||||III US005478731A United States Patent (19) 11 Patent Number: 5,478,731
|||||||III US005478731A United States Patent (19) 11 Patent Number: 5,478,731 Short 45 Date of Patent: Dec. 26,9 1995 54). POLYCOS VECTORS 56 References Cited 75) Inventor: Jay M. Short, Encinitas, Calif. PUBLICATIONS (73 Assignee: Stratagene, La Jolla, Calif. Ahmed (1989), Gene 75:315-321. 21 Appl. No.: 133,179 Evans et al. (1989), Gene 79:9-20. 22) PCT Filed: Apr. 10, 1992 Primary Examiner-Mindy B. Fleisher Assistant Examiner-Philip W. Carter 86 PCT No.: PCT/US92/03012 Attorney, Agent, or Firm-Albert P. Halluin; Pennie & S371 Date: Oct. 12, 1993 Edmonds S 102(e) Date: Oct. 12, 1993 57 ABSTRACT 87, PCT Pub. No.: WO92/18632 A bacteriophage packaging site-based vector system is describe that involves cloning vectors and methods for their PCT Pub. Date: Oct. 29, 1992 use in preparing multiple copy number bacteriophage librar O ies of cloned DNA. The vector is based on a DNA segment Related U.S. Application Data that comprises a nucleotide sequence defining a bacterioph 63 abandoned.continuationin-part of ser, No. 685.215,y Apr 12, 1991, ligationage packaging means usedsite locatedto concatamerize between twofragments termining of DNA 6 having compatible ligation means. Methods for preparing a (51) Int. Cl. ............................... C12N 1/21; C12N 7/01; concatameric DNA for packaging cloned DNA segments, C12N 15/10; C12N 15/11 and for packaging the concatamers to produce a library are 52 U.S. Cl. ................ 435/914; 435/1723; 435/252.33; also described. 435/235.1; 435/252.3; 536/23.1 58) Field of Search .............................. 435/91.32, 172.3, 435/320.1,914, 252.33, 252.3, 235.1; 536/23.1 18 Claims, 1 Drawing Sheet U.S. -
Lessons from Nature: Microrna-Based Shrna Libraries
PERSPECTIVE Lessons from Nature: microRNA-based shRNA libraries methods Kenneth Chang1, Stephen J Elledge2 & Gregory J Hannon1 Loss-of-function genetics has proven essential for interrogating the functions of genes .com/nature e and for probing their roles within the complex circuitry of biological pathways. In .natur many systems, technologies allowing the use of such approaches were lacking before w the discovery of RNA interference (RNAi). We have constructed first-generation short hairpin RNA (shRNA) libraries modeled after precursor microRNAs (miRNAs) and second- http://ww generation libraries modeled after primary miRNA transcripts (the Hannon-Elledge oup libraries). These libraries were arrayed, sequence-verified, and cover a substantial portion r G of all known and predicted genes in the human and mouse genomes. Comparison of first- and second-generation libraries indicates that RNAi triggers that enter the RNAi pathway lishing through a more natural route yield more effective silencing. These large-scale resources b Pu are functionally versatile, as they can be used in transient and stable studies, and for constitutive or inducible silencing. Library cassettes can be easily shuttled into vectors Nature that contain different promoters and/or that provide different modes of viral delivery. 6 200 © RNAi is an evolutionarily conserved, sequence-specific than a decade elapsed between the discovery of the first gene-silencing mechanism that is induced by dsRNA. miRNA, Caenorhabditis elegans lin-4 (refs. 11,12) and Each dsRNA silencing trigger is processed into 21–25 bp the achievement of at least a superficial understanding dsRNAs called small interfering RNAs (siRNAs)1–3 by of the biosynthesis, processing and mode of action of Dicer, a ribonuclease III family (RNase III) enzyme4. -
Site Directed Mutagensis of Bacteriophage HK639 and Identification of Its Integration Site Madhuri Jonnalagadda Western Kentucky University
Western Kentucky University TopSCHOLAR® Masters Theses & Specialist Projects Graduate School 12-2008 Site Directed Mutagensis of Bacteriophage HK639 and Identification of Its Integration Site Madhuri Jonnalagadda Western Kentucky University Follow this and additional works at: http://digitalcommons.wku.edu/theses Part of the Cell and Developmental Biology Commons, Genetics Commons, Immunopathology Commons, and the Molecular Genetics Commons Recommended Citation Jonnalagadda, Madhuri, "Site Directed Mutagensis of Bacteriophage HK639 and Identification of Its Integration Site" (2008). Masters Theses & Specialist Projects. Paper 42. http://digitalcommons.wku.edu/theses/42 This Thesis is brought to you for free and open access by TopSCHOLAR®. It has been accepted for inclusion in Masters Theses & Specialist Projects by an authorized administrator of TopSCHOLAR®. For more information, please contact [email protected]. SITE DIRECTED MUTAGENESIS OF BACTERIOPHAGE HK639 AND IDENTIFICATION OF ITS INTEGRATION SITE A Thesis presented to The faculty of the Department of Biology Western Kentucky University Bowling Green, Kentucky. In Partial Fulfillment Of the Requirement for the Degree Master of Science By Madhuri Jonnalagadda December, 2008 Site Directed Mutagenesis of Bacteriophage HK639 and Identification of its Integration Site Date Recommended 12/4/08 Dr.Rodney A. King Director of Thesis __Dr.Jeffery Marcus Dr. Sigrid Jacobshagen _____________________________________ Dean, Graduate Studies and Research Date DEDICATION I would like to dedicate my thesis to my dear father Dr. J. Padmanabha Rao, my mother, Dr.V. Lakshmi, my sister Dr. J. Sushma for their support and encouragement. i ACKNOWLEDGEMENTS I wish to express my heartfelt gratitude to my graduate committee in the Department of Biology, Western Kentucky University. Primarily, I am thankful to my advisor, Dr. -
The Eighth Day of Creation”: Looking Back Across 40 Years to the Birth of Molecular Biology and the Roots of Modern Cell Biology
“The Eighth Day of Creation”: looking back across 40 years to the birth of molecular biology and the roots of modern cell biology Mark Peifer1 1 Department of Biology and Curriculum in Genetics and Molecular Biology, University of North Carolina at Chapel Hill, CB#3280, Chapel Hill, NC 27599-3280, USA * To whom correspondence should be addressed Email: [email protected] Phone: (919) 962-2272 1 Forty years ago, Horace Judson’s “The Eight Day of Creation” was published, a book vividly recounting the foundations of modern biology, the molecular biology revolution. This book inspired many in my generation. The anniversary provides a chance for a new generation to take a look back, to see how science has changed and hasn’t changed. Many central players in the book, including Sydney Brenner, Seymour Benzer and Francois Jacob, would go on to be among the founders of modern cell, developmental, and neurobiology. These players come alive via their own words, as complex individuals, both heroes and anti-heroes. The technologies and experimental approaches they pioneered, ranging from cell fractionation to immunoprecipitation to structural biology, and the multidisciplinary approaches they took continue to power and inspire our work today. In the process, Judson brings out of the shadows the central roles played by women in many of the era’s discoveries. He provides us with a vision of how science and scientists have changed, of how many things about our endeavor never change, and how some new ideas are perhaps not as new as we’d like to think. 2 In 1979 Horace Judson completed a ten-year project about cell and molecular biology’s foundations, unveiling “The Eighth Day of Creation”, a book I view as one of the most masterful evocations of a scientific revolution (Judson, 1979). -
MORC1 Represses Transposable Elements in the Mouse Male Germline
ARTICLE Received 12 Sep 2014 | Accepted 7 Nov 2014 | Published 12 Dec 2014 DOI: 10.1038/ncomms6795 OPEN MORC1 represses transposable elements in the mouse male germline William A. Pastor1,*, Hume Stroud1,*,w, Kevin Nee1, Wanlu Liu1, Dubravka Pezic2, Sergei Manakov2, Serena A. Lee1, Guillaume Moissiard1, Natasha Zamudio3,De´borah Bourc’his3, Alexei A. Aravin2, Amander T. Clark1,4 & Steven E. Jacobsen1,4,5 The Microrchidia (Morc) family of GHKL ATPases are present in a wide variety of prokaryotic and eukaryotic organisms but are of largely unknown function. Genetic screens in Arabidopsis thaliana have identified Morc genes as important repressors of transposons and other DNA-methylated and silent genes. MORC1-deficient mice were previously found to display male-specific germ cell loss and infertility. Here we show that MORC1 is responsible for transposon repression in the male germline in a pattern that is similar to that observed for germ cells deficient for the DNA methyltransferase homologue DNMT3L. Morc1 mutants show highly localized defects in the establishment of DNA methylation at specific classes of transposons, and this is associated with failed transposon silencing at these sites. Our results identify MORC1 as an important new regulator of the epigenetic landscape of male germ cells during the period of global de novo methylation. 1 Department of Molecular, Cell and Developmental Biology, University of California Los Angeles, 4028 Terasaki Life Sciences Building, 610 Charles E. Young Drive East, Los Angeles, California 90095, USA. 2 Division of Biology and Biochemical Engineering, California Institute of Technology, 1200 E California Boulevard, Pasadena, California 91125, USA. 3 Unite´ de ge´ne´tique et biologie du de´veloppement, Instititute Curie, CNRS UMR3215, INSERM U934, Paris 75005, France. -
6 Women Scientists Who Were Snubbed Due to Sexism Despite Enormous Progress in Recent Decades, Women Still Have to Deal with Biases Against Them in the Sciences
6 Women Scientists Who Were Snubbed Due to Sexism Despite enormous progress in recent decades, women still have to deal with biases against them in the sciences. BY JANE J. LEE, NATIONAL GEOGRAPHIC PUBLISHED MAY 19, 2013 In April, National Geographic News published a story about the letter in which scientist Francis Crick described DNA to his 12-year-old son. In 1962, Crick was awarded a Nobel Prize for discovering the structure of DNA, along with fellow scientists James Watson and Maurice Wilkins. Several people posted comments about our story that noted one name was missing from the Nobel roster: Rosalind Franklin, a British biophysicist who also studied DNA. Her data were critical to Crick and Watson's work. But it turns out that Franklin would not have been eligible for the prize—she had passed away four years before Watson, Crick, and Wilkins received the prize, and the Nobel is never awarded posthumously. But even if she had been alive, she may still have been overlooked. Like many women scientists, Franklin was robbed of recognition throughout her career (See her section below for details.) She was not the first woman to have endured indignities in the male- dominated world of science, but Franklin's case is especially egregious, said Ruth Lewin Sime, a retired chemistry professor at Sacramento City College who has written on women in science. Over the centuries, female researchers have had to work as "volunteer" faculty members, seen credit for significant discoveries they've made assigned to male colleagues, and been written out of textbooks. -
Herpesviral Latency—Common Themes
pathogens Review Herpesviral Latency—Common Themes Magdalena Weidner-Glunde * , Ewa Kruminis-Kaszkiel and Mamata Savanagouder Department of Reproductive Immunology and Pathology, Institute of Animal Reproduction and Food Research of Polish Academy of Sciences, Tuwima Str. 10, 10-748 Olsztyn, Poland; [email protected] (E.K.-K.); [email protected] (M.S.) * Correspondence: [email protected] Received: 22 January 2020; Accepted: 14 February 2020; Published: 15 February 2020 Abstract: Latency establishment is the hallmark feature of herpesviruses, a group of viruses, of which nine are known to infect humans. They have co-evolved alongside their hosts, and mastered manipulation of cellular pathways and tweaking various processes to their advantage. As a result, they are very well adapted to persistence. The members of the three subfamilies belonging to the family Herpesviridae differ with regard to cell tropism, target cells for the latent reservoir, and characteristics of the infection. The mechanisms governing the latent state also seem quite different. Our knowledge about latency is most complete for the gammaherpesviruses due to previously missing adequate latency models for the alpha and beta-herpesviruses. Nevertheless, with advances in cell biology and the availability of appropriate cell-culture and animal models, the common features of the latency in the different subfamilies began to emerge. Three criteria have been set forth to define latency and differentiate it from persistent or abortive infection: 1) persistence of the viral genome, 2) limited viral gene expression with no viral particle production, and 3) the ability to reactivate to a lytic cycle. This review discusses these criteria for each of the subfamilies and highlights the common strategies adopted by herpesviruses to establish latency. -
Bacterial Virus Ontology; Coordinating Across Databases
viruses Article Bacterial Virus Ontology; Coordinating across Databases Chantal Hulo 1, Patrick Masson 1, Ariane Toussaint 2, David Osumi-Sutherland 3, Edouard de Castro 1, Andrea H. Auchincloss 1, Sylvain Poux 1, Lydie Bougueleret 1, Ioannis Xenarios 1 and Philippe Le Mercier 1,* 1 Swiss-Prot group, SIB Swiss Institute of Bioinformatics, CMU, University of Geneva Medical School, 1211 Geneva, Switzerland; [email protected] (C.H.); [email protected] (P.M.); [email protected] (E.d.C.); [email protected] (A.H.A.); [email protected] (S.P.); [email protected] (L.B.); [email protected] (I.X.) 2 University Libre de Bruxelles, Génétique et Physiologie Bactérienne (LGPB), 12 rue des Professeurs Jeener et Brachet, 6041 Charleroi, Belgium; [email protected] 3 European Molecular Biology Laboratory, European Bioinformatics Institute (EMBL-EBI), Wellcome Trust Genome Campus, Hinxton CB10 1SD, UK; [email protected] * Correspondence: [email protected]; Tel.: +41-22379-5870 Academic Editors: Tessa E. F. Quax, Matthias G. Fischer and Laurent Debarbieux Received: 13 April 2017; Accepted: 17 May 2017; Published: 23 May 2017 Abstract: Bacterial viruses, also called bacteriophages, display a great genetic diversity and utilize unique processes for infecting and reproducing within a host cell. All these processes were investigated and indexed in the ViralZone knowledge base. To facilitate standardizing data, a simple ontology of viral life-cycle terms was developed to provide a common vocabulary for annotating data sets. New terminology was developed to address unique viral replication cycle processes, and existing terminology was modified and adapted.