DOCSLIB.ORG

Avian and Swine Flu (Learning Objectives)

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
Avian and Swine Flu (Learning Objectives) Acellular Biological Entities: Viruses, Viroids, & Prions (Outline) • Acellular entities as infectious agents of animal and plant diseases • Structure and functional properties. • Viral structural components: genome (DNA or RNA), capsid, nucleocapsid, and envelope. Naked and enveloped viruses • Parasitic nature of viruses – Life cycle of bacteriophages and relationship to human disease – Host-cell specificity: common human diseases – Life cycle of animal viruses and association with susceptibility to infection. – Human genetic variability in susceptibility to viral infections • Life cycle of the Ebola virus • Life cycle of a retrovirus such as HIV • Role of ancient and current retroviruses: – In shaping the human genome; addition of genetic variability – as selective pressure for human genetic variability Acellular Disease-causing biological entities (Health Connection) Simple infectious agents Virus- genetic material in transit from one host cell to the next Viroid- Circular naked RNA Prion- misfolded infectious proteins Viroids and Prions: The Simplest Infectious Agents • Viroids are circular RNA molecules that infect plants and disrupt their growth- Cadang-Cadang of coconut trees • Prions are slow-acting, virtually indestructible infectious proteins that cause brain diseases in mammals Prion diseases • Prions are mis-folded infectious proteins, lack nucleic acids • Prions cause disease by converting normal proteins into the prion version • Diseases caused by prions affect the nervous system Scrapie in sheep Mad cow disease Kuru in humans Creutzfeldt-Jakob Disease (CJD) in humans Fatal Familial Insomnia (FFI) The Truth Will Out: Is vCJD Caused by BSE? http://ffh.films.com/PreviewClip.aspx?id=5955 (5 mins) Acellular Disease-causing biological entities (Health Connection) Virus • Childhood diseases • Age-independent disease • Emerging diseases – Discovery Channel Video Clip (Textbook site) Viroid • Plant diseases Prion • Scarpie • Mad Cow disease • Kuru- Fore tribe of Papua New Guinea Viruses are genes packaged in protein – Biological non-living entities – Have no cytoplasm – Cannot self-replicate – Cannot metabolize – Genetic material either DNA or RNA never both Viruses • To replicate they need to infect a living cell • Every living cells has one or more viruses that can infect it, specifically. Viral Shapes Naked Enveloped Complex RNA Membranous Head DNA envelope RNA Capsomere DNA Capsid Tail sheath Capsomere Tail of capsid fiber Glycoprotein Glycoproteins 18 250 nm 70–90 nm (diameter) 80–200 nm (diameter) 80 225 nm 20 nm 50 nm 50 nm 50 nm (a) Tobacco mosaic (b) Adenoviruses (c) Influenza viruses (d) Bacteriophage T4 virus Viral Structures • Virion: an individual viral particle • Capsid: protein coat surrounding the nucleic acid Capsid made of individual protein subunits (capsomeres) gives the virion its shape • Nucleocapsid- nucleic acid and protein capsid Basis of Host-Range of Viruses • Host range is determined by “lock-and-key” fit between virus surface and cellular receptors on host cell • Most viruses infect only specific types of cells in one host Narrow host range with tissue specificity – cold viruses: upper respiratory tract cells. – HIV, AIDS virus: a certain white blood cell. • Some have a broad host-range infecting multiple species – rabies Viral genomes are made of either DNA or RNA – Flu viruses are RNA – Genital warts virus (HPV) and Herpes virus are DNA viruses http://www.cdc.gov/STD/HPV/STDFact-HPV.htm Membranous envelope RN A Protein coat Glycoprotein spike Influenza HPV Plant viruses are serious agricultural pests – Most plant viruses have RNA genomes Enter their hosts via wounds in the plant’s outer layers Protein RNA Emerging viruses threaten human health × × Colorized TEM 50,000 Colorized Colorized TEM 370,000 Colorized Figure 10.20A, B Ebola Virus (RNA) SARS Virus (RNA) Bacteriophage Life Cycles Daughter cell with prophage Phage The phage injects its DNA. DNA Cell divisions produce population of Phage DNA Phage bacteria infected circularizes. with the prophage. Bacterial chromosome Occasionally, a prophage exits the bacterial chromosome, initiating a lytic cycle. Lytic cycle Lysogenic cycle The bacterium reproduces, The cell lyses, releasing phages. copying the prophage and transmitting it to daughter cells. Lytic cycle or Lysogenic cycle Prophage is induced is entered New phage DNA and proteins Phage DNA integrates into are synthesized and the bacterial chromosome, assembled into phages. becoming a prophage. Bacteriophage Life Cycles Lytic Cycle Lysogenic Cycle • Attachment • Attachment • Entry of DNA • Entry of DNA • Degradation of host DNA • No degradation of host • Replication of nucleic DNA acid and synthesis of • Integration of nucleic into viral proteins bacterial genome • Packaging/Assembly of • Prophage: an integrated phage particles (DNA phage and proteins) • Exit to lytic cycle induced • Release by cell lysis by chemicals and high energy radiation Prophage-mediated Diseases • One of many reasons for why bacteria cause disease is the production of a toxic protein. • Some proviral genes code for toxic proteins. • Examples: o Diphtheria o Botulism o Scarlet fever o E. coli food poisoning Animal Virus Life Cycle • Attachment • Entry ? • Uncoating of virion separate protein from NA • Replication of nucleic acid and synthesis of viral proteins • Maturation of virions (assembly of NA and proteins) • Release: cell lysis or budding http://www.youtube.com/watch?v=cE 0qdqoBFa8 The Ebola virus – An enveloped RNA (- strand) Entry and exit – http://www.youtube.com/watch?v=57P6MuM3_F8 Pathogenesis – http://www.openculture.com/2014/11/the-ebola-virus- explained-with-animated-video.html Transmission Links http://www.cdc.gov/vhf/ebola/transmission/index.html?s_cid= cs_284 http://www.who.int/mediacentre/factsheets/fs103/en/ The AIDS virus – HIV is an RNA retrovirus – It makes DNA using RNA template – Inside a cell, HIV uses its RNA as a template to make a DNA copy of itself, which integrates into the host genome. http://www.susanahalpine.com/anim/KubyHTML/HIV.htm Envelope Glycoprotein Protein coat RNA (two identical strands) Reverse transcriptase Viral DNA in the Human Genome About 8% of our genome is derived from RNA viruses called retroviruses - This is evidence of past infection - Sequences tend to increase over time Figure 11.11 Roles of human endogenous retroviruses Endogenous retroviruses • Placenta formation • Large Brain development • Powerful emotions Explorer: The virus hunters (DVD) Natgeotv.vom http://channel.nationalgeographic.com/series/expl orer/3828/Overview#tab-Videos/06253_00 The Virus Hunters (DVD) • Retroviruses in human genomes (first 12:30 mins) Role for Viruses in shaping the Human Genome • Past retroviral infection in a primate ancestor – Insertion of sequences – New proteins or protein domains for host that maybe beneficial and influence behavior • Present retroviral infections add to the genetic variability of the human populations The Virus Hunters (DVD) • Role of ancient retroviruses in major evolutionary steps (12:30- 15:30 mins) The Virus Hunters (DVD) • Role of integrated viruses in complex emotions and behavior (~40:30 to 46:20 mins) .
Load more

Recommended publications
  • Inhibition of Chloroplast DNA Recombination and Repair by Dominant Negative Mutants of Escherichia Coli Reca
    University of Nebraska - Lincoln DigitalCommons@University of Nebraska - Lincoln Faculty Publications from the Center for Plant Science Innovation Plant Science Innovation, Center for June 1995 Inhibition of Chloroplast DNA Recombination and Repair by Dominant Negative Mutants of Escherichia coli RecA Heriberto D. Cerutti University of Nebraska - Lincoln, [email protected] Anita M. Johnson Duke University, Durham, North Carolina John E. Boynton Duke University, Durham, North Carolina Nicholas W. Gillham Duke University, Durham, North Carolina Follow this and additional works at: https://digitalcommons.unl.edu/plantscifacpub Part of the Plant Sciences Commons Cerutti, Heriberto D.; Johnson, Anita M.; Boynton, John E.; and Gillham, Nicholas W., "Inhibition of Chloroplast DNA Recombination and Repair by Dominant Negative Mutants of Escherichia coli RecA" (1995). Faculty Publications from the Center for Plant Science Innovation. 8. https://digitalcommons.unl.edu/plantscifacpub/8 This Article is brought to you for free and open access by the Plant Science Innovation, Center for at DigitalCommons@University of Nebraska - Lincoln. It has been accepted for inclusion in Faculty Publications from the Center for Plant Science Innovation by an authorized administrator of DigitalCommons@University of Nebraska - Lincoln. MOLECULAR AND CELLULAR BIOLOGY, June 1995, p. 3003–3011 Vol. 15, No. 6 0270-7306/95/$04.0010 Copyright q 1995, American Society for Microbiology Inhibition of Chloroplast DNA Recombination and Repair by Dominant Negative Mutants of Escherichia coli RecA HERIBERTO CERUTTI, ANITA M. JOHNSON, JOHN E. BOYNTON,* AND NICHOLAS W. GILLHAM Developmental, Cell and Molecular Biology Group, Departments of Botany and Zoology, Duke University, Durham, North Carolina 27708 Received 7 December 1994/Returned for modification 12 January 1995/Accepted 28 February 1995 The occurrence of homologous DNA recombination in chloroplasts is well documented, but little is known about the molecular mechanisms involved or their biological significance.
    [Show full text]
  • Evaluation of Prophage Gene Revealed Population Variation Of
    Evaluation of Prophage Gene Revealed Population Variation of ‘Candidatus Liberibacter Asiaticus’: Bacterial Pathogen of Citrus Huanglongbing (HLB) in Northern Thailand Jutamas Kongjak Chiang Mai University Angsana Akarapisan ( [email protected] ) Chiang Mai University https://orcid.org/0000-0002-0506-8675 Research Article Keywords: Citrus, Prophage, Bacteriophage, Huanglongbing, Candidatus Liberibacter asiaticus Posted Date: August 24th, 2021 DOI: https://doi.org/10.21203/rs.3.rs-822974/v1 License: This work is licensed under a Creative Commons Attribution 4.0 International License. Read Full License Page 1/15 Abstract ‘Candidatus Liberibacter asiaticus’ is a non-culturable bacterial pathogen, the causal agent of Huanglongbing (HLB, yellow shoot disease, also known as citrus greening disease), a highly destructive disease of citrus (Rutaceae). The pathogen is transmitted by the Asian citrus psyllid: Diaphorina citri Kuwayama. Recent studies, have shown that the HLB pathogen has two prophages, SC1 that has a lytic cycle and SC2 associated with bacterial virulence. This study aimed to search for SC1 and SC2 prophages of HLB in mandarin orange, sweet orange, bitter orange, kumquat, key lime, citron, caviar lime, kar lime, pomelo and orange jasmine from ve provinces in Northern Thailand. A total of 216 samples collected from Northern Thailand during 2019 and 2020 were studied. The results revealed that 62.04% (134/216) citrus samples were infected with the ‘Ca. L. asiaticus’ the bacterial pathogen associated with citrus HLB. The prophage particles are important genetic elements of bacterial genomes that are involved in lateral gene transfer, pathogenicity, environmental adaptation and interstrain genetic variability. Prophage particles were evaluated in the terminase gene of SC1 and SC2-type prophages.
    [Show full text]
  • State of Prophage Mu DNA Upon Induction (Bacteriophage Mu/Bacteriophage X/DNA Insertion/DNA Excision/Transposable Elements) E
    Proc. Nati. Acad. Sci. USA Vol. 74, No. 8, pp. 3143-3147, August 1977 Biochemistry State of prophage Mu DNA upon induction (bacteriophage Mu/bacteriophage X/DNA insertion/DNA excision/transposable elements) E. LjUNGQUIST AND A. I. BUKHARI Cold Spring Harbor Laboratory, Cold Spring Harbor, New York 11724 Communicated by J. D. Watson, April 18, 1977 ABSTRACT We have compared the process of prophage different host sequences. Yet, a form of Mu DNA free of host A induction with that of prophage Mu. According to the DNA has remained undetected. Campbell model, rescue of A DNA from the host DNA involves In its continuous association with host DNA, Mu resembles reversal of X integration such that the prophage DNA is excised from the host chromosome. We have monitored this event by another class of insertion elements, referred to as the trans- locating the prophage DNA with a technique in which DNA of posable elements. The transposable elements are specific the lysogenic cells is cleaved with a restriction endonuclease stretches of DNA that can be translocated from one position to and fractionated in agarose gels. The DNA fragments are de- another in host DNA (7). Mu undergoes multiple rounds of natured in gels, transferred to a nitrocellulose paper, and hy- transposition during its growth, far exceeding the transposition bridized with 32P-labeled mature phage DNA. The fragments frequency of the bonafide transposable elements. When a Mu containing prophage DNA become visible after autoradiogra- lysogen, carrying a single Mu prophage at a given site on the phy. Upon prophage A induction, the phage-host junction fragments disappear and the fragment containing the A att site host chromosome, is induced, many copies of Mu DNA are appears.
    [Show full text]
  • Philympics 2021: Prophage Predictions Perplex Programs
    bioRxiv preprint doi: https://doi.org/10.1101/2021.06.03.446868; this version posted June 3, 2021. The copyright holder for this preprint (which was not certified by peer review) is the author/funder, who has granted bioRxiv a license to display the preprint in perpetuity. It is made available under aCC-BY-NC-ND 4.0 International license. 1 Philympics 2021: Prophage 2 Predictions Perplex Programs 3 Michael J. Roach1*, Katelyn McNair2, Sarah K. Giles1, Laura Inglis1, Evan Pargin1, Przemysław 4 Decewicz3, Robert A. Edwards1 5 1. Flinders Accelerator for Microbiome Exploration, Flinders University, 5042, SA, Australia 6 2. Computational Sciences Research Center, San Diego State University, San Diego, 92182, CA, USA 7 3. Department of Environmental Microbiology and Biotechnology, Institute of Microbiology, Faculty 8 of Biology, University of Warsaw, Warsaw, 02-096, Poland 9 10 *Corresponding Author: [email protected] 11 12 Abstract 13 Most bacterial genomes contain integrated bacteriophages—prophages—in various states of decay. 14 Many are active and able to excise from the genome and replicate, while others are cryptic 15 prophages, remnants of their former selves. Over the last two decades, many computational tools 16 have been developed to identify the prophage components of bacterial genomes, and it is a 17 particularly active area for the application of machine learning approaches. However, progress is 18 hindered and comparisons thwarted because there are no manually curated bacterial genomes that 19 can be used to test new prophage prediction algorithms. 20 Here, we present a library of gold-standard bacterial genome annotations that include manually 21 curated prophage annotations, and a computational framework to compare the predictions from 22 different algorithms.
    [Show full text]
  • First Description of a Temperate Bacteriophage (Vb Fhim KIRK) of Francisella Hispaniensis Strain 3523
    viruses Article First Description of a Temperate Bacteriophage (vB_FhiM_KIRK) of Francisella hispaniensis Strain 3523 Kristin Köppen 1,†, Grisna I. Prensa 1,†, Kerstin Rydzewski 1, Hana Tlapák 1, Gudrun Holland 2 and Klaus Heuner 1,* 1 Centre for Biological Threats and Special Pathogens, Cellular Interactions of Bacterial Pathogens, ZBS 2, Robert Koch Institute, 13353 Berlin, Germany; [email protected] (K.K.); [email protected] (G.I.P.); [email protected] (K.R.); [email protected] (H.T.) 2 Centre for Biological Threats and Special Pathogens, Advanced Light and Electron Microscopy, ZBS 4, Robert Koch Institute, D-13353 Berlin, Germany; [email protected] * Correspondence: [email protected]; Tel.: +49-30-18754-2226 † Both authors contributed equally to this work. Abstract: Here we present the characterization of a Francisella bacteriophage (vB_FhiM_KIRK) includ- ing the morphology, the genome sequence and the induction of the prophage. The prophage sequence (FhaGI-1) has previously been identified in F. hispaniensis strain 3523. UV radiation induced the prophage to assemble phage particles consisting of an icosahedral head (~52 nm in diameter), a tail of up to 97 nm in length and a mean width of 9 nm. The double stranded genome of vB_FhiM_KIRK contains 51 open reading frames and is 34,259 bp in length. The genotypic and phylogenetic analysis indicated that this phage seems to belong to the Myoviridae family of bacteriophages. Under the Citation: Köppen, K.; Prensa, G.I.; conditions tested here, host cell (Francisella hispaniensis 3523) lysis activity of KIRK was very low, and Rydzewski, K.; Tlapák, H.; Holland, the phage particles seem to be defective for infecting new bacterial cells.
    [Show full text]
  • Molecular Model for the Transposition and Replication of Bacteriophage
    Proc. Natl. Acad. Sci. USA Vol. 76, No. 4, pp. 1933-1937, April 1979 Genetics Molecular model for the transposition and replication of bacteriophage Mu and other transposable elements (DNA insertion elements/nonhomologous recombination/site-specific recombination/replicon fusion/topoisomerases) JAMES A. SHAPIRO Department of Microbiology, The University of Chicago, Chicago, Illinois 60637 Communicated by Hewson Swift, December 11, 1978 ABSTRACT A series of molecular events will explain how B genetic elements can transpose from one DNA site to another, B y generate a short oligonucleotide duplication at both ends of the I % new insertion site, and replicate in the transposition process. I These events include the formation of recombinant molecules A a% /; C which have been postulated to be intermediates in the trans- position process. The model explains how the replication of bacteriophage Mu is obligatorily associated with movement to z x x new genetic sites. It postulates that all transposable elements replicate in the transposition process so that they remain at their z original site while moving to new sites. According to this model, the mechanism of transposition is very different from the in- V sertion and excision of bacteriophage X. y FIG. 1. Replicon fusion. The boxes with an arrow indicate copies Recent research on transposable elements in bacteria has pro- of a transposable element. The letters mark arbitrary regions of the vided important insights into the role of nonhomologous re- two replicons to indicate the relative positions of the elements in the combination in genetic rearrangements (1-4). These elements donor and cointegrate molecules. include small insertion sequences (IS elements), transposable resistance determinants (Tn elements), and bacteriophage Mu results in the duplication of a short oligonucleotide sequence (3).
    [Show full text]
  • GIANT CHLOROPLAST 1 Is Essential for Correct Plastid Division in Arabidopsis
    View metadata, citation and similar papers at core.ac.uk brought to you by CORE provided by Elsevier - Publisher Connector Current Biology, Vol. 14, 776–781, May 4, 2004, 2004 Elsevier Ltd. All rights reserved. DOI 10.1016/j.cub.2004.04.031 GIANT CHLOROPLAST 1 Is Essential for Correct Plastid Division in Arabidopsis Jodi Maple,1 Makoto T. Fujiwara,1,2 ing frames. Although no functional information exists, Nobutaka Kitahata,2 Tracy Lawson,3 All2390 and Slr1223 were initially annotated as cell divi- Neil R. Baker,3 Shigeo Yoshida,2 sion-inhibitor SulA proteins. Alignment of the GC1 amino and Simon Geir Møller1,* acid sequence (347 amino acids) with the Anabaena sp. ;similarity %65ف 1Department of Biology PCC 7120 All2390 sequence revealed University of Leicester however, GC1 contained a 45 amino acid N-terminal Leicester LE1 7RH extension absent in Anabaena sp. predicted to harbor United Kingdom a 37 amino acid plastid-targeting transit peptide (Figure 2 Plant Functions Laboratory 1A). Phylogenetic analysis using eleven GC1 homologs RIKEN from bacteria, mammals, Drosophila, and Arabidopsis Hirosawa 2-1, Wako, Saitama 351-0198 demonstrated a close relationship between GC1 and Japan GC1-like proteins from cyanobacteria, indicating a cya- 3 Department of Biological Sciences nobacterial origin of GC1 (Figure 1B). -overall identity to prokaryotic nucleo %40ف University of Essex GC1 has Colchester CO4 3SQ tide-sugar epimerases, and secondary structure predic- structural (%90–%80ف) United Kingdom tions showed that GC1 has high similarity to epimerases in the active site region. Epi- merases control and change the stereochemistry of car- Summary bohydrate-hydroxyl substitutions, often modifying pro- tein activity or surface recognition, and epimerases Plastids are vital plant organelles involved in many contain two crucial active site residues (S and Y) vital essential biological processes [1, 2].
    [Show full text]
  • Introduction to Viroids and Prions
    Harriet Wilson, Lecture Notes Bio. Sci. 4 - Microbiology Sierra College Introduction to Viroids and Prions Viroids – Viroids are plant pathogens made up of short, circular, single-stranded RNA molecules (usually around 246-375 bases in length) that are not surrounded by a protein coat. They have internal base-pairs that cause the formation of folded, three-dimensional, rod-like shapes. Viroids apparently do not code for any polypeptides (proteins), but do cause a variety of disease symptoms in plants. The mechanism for viroid replication is not thoroughly understood, but is apparently dependent on plant enzymes. Some evidence suggests they are related to introns, and that they may also infect animals. Disease processes may involve RNA-interference or activities similar to those involving mi-RNA. Prions – Prions are proteinaceous infectious particles, associated with a number of disease conditions such as Scrapie in sheep, Bovine Spongiform Encephalopathy (BSE) or Mad Cow Disease in cattle, Chronic Wasting Disease (CWD) in wild ungulates such as muledeer and elk, and diseases in humans including Creutzfeld-Jacob disease (CJD), Gerstmann-Straussler-Scheinker syndrome (GSS), Alpers syndrome (in infants), Fatal Familial Insomnia (FFI) and Kuru. These diseases are characterized by loss of motor control, dementia, paralysis, wasting and eventually death. Prions can be transmitted through ingestion, tissue transplantation, and through the use of comtaminated surgical instruments, but can also be transmitted from one generation to the next genetically. This is because prion proteins are encoded by genes normally existing within the brain cells of various animals. Disease is caused by the conversion of normal cell proteins (glycoproteins) into prion proteins.
    [Show full text]
  • Effects of Prophage Regions in a Plasmid Carrying a Carbapenemase Gene on Survival Against Antibiotic Stress
    International Journal of Antimicrobial Agents 53 (2019) 89–94 Contents lists available at ScienceDirect International Journal of Antimicrobial Agents journal homepage: www.elsevier.com/locate/ijantimicag Short Communication Effects of prophage regions in a plasmid carrying a carbapenemase gene on survival against antibiotic stress ∗ So Yeon KIM, Kwan Soo KO Department of Molecular Cell Biology, Samsung Medical Center, Sungkyunkwan University School of Medicine, Suwon, South Korea a r t i c l e i n f o a b s t r a c t Article history: We investigated the evolutionary importance of cryptic prophage elements in a bla NDM-1 -bearing plas- Received 23 May 2018 mid by exploring the effect of prophage regions on survival against antibiotic stress. While analysing Accepted 10 September 2018 a plasmid harboring an NDM-1-encoding gene in Klebsiella pneumoniae from South Korea, we found a prophage region within the plasmid. We constructed single-prophage knockout (KO) mutants by gene re- Editor: Professor Jian Li placement. The intact plasmid and plasmids with deleted prophages were conjugated into Escherichia coli DH5 α. Growth rate and antibiotic susceptibility were determined, and survival rates of strains Keywords: were evaluated in the presence of antibiotics, such as imipenem, amikacin, gentamicin, cefotaxime, and New Delhi metallo- β-lactamase plasmid piperacillin/tazobactam. A transcriptional response of sigma factor-coding genes (rpoS and rpoE) and re- prophage active oxygen species (ROS)-related genes from different operons (soxS, fumC, oxyR, and katE) to a sub- inhibitory concentration of aminoglycosides was monitored by quantitative real-time polymerase chain reaction (qRT-PCR). The prophage region consists of four cryptic prophages of 16,795 bp and 19 coding DNA sequences.
    [Show full text]
  • An Efficient, Counter-Selection-Based Method for Prophage Curing In
    viruses Article An Efficient, Counter-Selection-Based Method for Prophage Curing in Pseudomonas aeruginosa Strains Esther Shmidov 1,2, Itzhak Zander 1,2, Ilana Lebenthal-Loinger 1, Sarit Karako-Lampert 3 , Sivan Shoshani 1,2 and Ehud Banin 1,2,* 1 The Mina and Everard Goodman Faculty of Life Sciences, Bar-Ilan University, Ramat-Gan 5290002, Israel; [email protected] (E.S.); [email protected] (I.Z.); [email protected] (I.L.-L.); [email protected] (S.S.) 2 The Institute of Nanotechnology and Advanced Materials, Bar-Ilan University, Ramat Gan 5290002, Israel 3 Scientific Equipment Center, The Mina & Everard Goodman Faculty of Life Sciences Bar-Ilan University, Ramat Gan 5290002, Israel; [email protected] * Correspondence: [email protected] Abstract: Prophages are bacteriophages in the lysogenic state, where the viral genome is inserted within the bacterial chromosome. They contribute to strain genetic variability and can influence bacterial phenotypes. Prophages are highly abundant among the strains of the opportunistic pathogen Pseudomonas aeruginosa and were shown to confer specific traits that can promote strain pathogenicity. The main difficulty of studying those regions is the lack of a simple prophage-curing method for P. aeruginosa strains. In this study, we developed a novel, targeted-curing approach for prophages in P. aeruginosa. In the first step, we tagged the prophage for curing with an ampicillin resistance cassette (ampR) and further used this strain for the sacB counter-selection marker’s temporal insertion into the prophage region. The sucrose counter-selection resulted in different variants when the prophage- Citation: Shmidov, E.; Zander, I.; cured mutant is the sole variant that lost the ampR cassette.
    [Show full text]
  • Prophages Domesticated by Bacteria Promote the Adaptability of Bacterial Cells
    BIOCELL Tech Science Press 2020 44(2): 157-166 Prophages domesticated by bacteria promote the adaptability of bacterial cells ZICHEN LIU1;YUNFENG DENG2;MENGZHI JI1;WENQING SUN2,*;XIANGYU FAN1,* 1 College of Biological Science and Technology, University of Jinan, Jinan, 250022, China 2 Shandong Provincial Chest Hospital, Jinan, 250013, China Key words: Temperate phage, Adaptation, Evolution, Ecological function Abstract: Prophages are temperate phages integrated into the host bacterial genome. They play an important role in the adaptation and the pathogenicity of bacteria, especially pathogenic bacteria. In this review, we described the distribution of prophages in different hosts and different environments, and focused on the significance of prophages. At the single- cell level, prophages can help the host adapt to harsh external environments by directly carrying virulence genes, encoding regulatory factors and activating lysogeny. At the population level, prophages can influence the overall evolutionary direction and ecological function of the host bacterial community. This review will help us understand the important role of prophages as unique organisms in individual bacteria and microbial populations. Introduction proteins such as transcriptional repressors, endolysins and holins. The lytic phages are usually used for phage treatment In 1915 and 1917, Fredrick Twort and Felix D’Herelle (Alisky because they can lyse cells in a short time. Some phage- et al., 1998; Twort, 1915) discovered bacteriophage for the first encoded proteins (lysins and holins) are also used for phage time in two separate studies. As a virus of bacteria, therapy because of their good tissue penetration, low bacteriophage can parasitize bacteria and use the energy and immunogenicity and low probability of bacterial resistance large-molecule synthesis systems of bacteria for (Drulis-Kawa et al., 2012).
    [Show full text]
  • Pervasive Domestication of Defective Prophages by Bacteria
    Pervasive domestication of defective prophages by bacteria Louis-Marie Bobaya,b,c,1, Marie Touchona,b, and Eduardo P. C. Rochaa,b aMicrobial Evolutionary Genomics, Institut Pasteur, 75724 Paris, France; bCNRS, UMR 3525, 75724 Paris, France; and cSorbonne Universités, UPMC, Université Paris 6, IFD, 75252 Paris Cedex 05, France Edited by W. Ford Doolittle, Dalhousie University, Halifax, NS, Canada, and approved July 7, 2014 (received for review March 21, 2014) Integrated phages (prophages) are major contributors to the local frequency of DNA motifs, suggesting adaptation of the diversity of bacterial gene repertoires. Domestication of their phage sequence to the requirements of the prophage state (15). components is thought to have endowed bacteria with molecular Independently of occasional contributions to bacterial fitness, systems involved in secretion, defense, warfare, and gene trans- intact prophages are molecular time bombs that kill their hosts fer. However, the rates and mechanisms of domestication remain upon activation of the lytic cycle (2). It has been shown that unknown. We used comparative genomics to study the evolution bacterial pseudogenes are under selection for rapid deletion of prophages within the bacterial genome. We identified over 300 from bacterial genomes (16, 17). Prophage inactivation should vertically inherited prophages within enterobacterial genomes. be under even stronger selection because these elements can kill Some of these elements are very old and might predate the split the cell. One might thus expect rapid genetic degradation of between Escherichia coli and Salmonella enterica. The size distri- prophages: either they activate the lytic cycle and kill the cell bution of prophage elements is bimodal, suggestive of rapid pro- before accumulating inactivating mutations or they are irre- phage inactivation followed by much slower genetic degradation.
    [Show full text]