Blog
About

  • Record: found
  • Abstract: found
  • Article: not found

The Legionella pneumophila GIG operon responds to gold and copper in planktonic and biofilm cultures

Read this article at

ScienceOpenPublisherPMC
Bookmark
      There is no author summary for this article yet. Authors can add summaries to their articles on ScienceOpen to make them more accessible to a non-specialist audience.

      Abstract

      Legionella pneumophila contaminates man-made water systems and creates numerous exposure risks for Legionnaires’ Disease. Because copper/silver ionization is commonly used to control L. pneumophila, its mechanisms of metal response and detoxification are of significant interest. Here we describe an L. pneumophila operon with significant similarity to the GIG operon of Cupriavidus metallidurans. The Legionella GIG operon is present in a subset of strains and has been acquired as part of the ICE-βox 65-kB integrative conjugative element. We assessed GIG promoter activity following exposure of L. pneumophila to multiple concentrations of HAuCl 4, CuSO 4 and AgNO 3. At 37°C, control stationary phase cultures exhibited GIG promoter activity. This activity increased significantly in response to 20 and 50uM HAuCl 4 and CuSO 4 but not in response to AgNO 3. Conversely, at 26°C, cultures exhibited decreased promoter response to copper. GIG promoter activity was also induced by HAuCl 4 or CuSO 4 during early biofilm establishment at both temperatures. When an L. pneumophila GIG promoter construct was transformed into E. coli DH5α, cultures showed baseline expression levels that did not increase following metal addition. Analysis of L. pneumophila transcriptional regulatory mutants suggested that GIG up-regulation in the presence of metal ions may be influenced by the stationary phase sigma factor, RpoS.

      Related collections

      Most cited references 52

      • Record: found
      • Abstract: found
      • Article: not found

      Quantification of biofilm structures by the novel computer program COMSTAT.

      The structural organization of four microbial communities was analysed by a novel computer program, COMSTAT, which comprises ten features for quantifying three-dimensional biofilm image stacks. Monospecies biofilms of each of the four bacteria, Pseudomonas: putida, P. aureofaciens, P. fluorescens and P. aeruginosa, tagged with the green fluorescent protein (GFP) were grown in flow chambers with a defined minimal medium as substrate. Analysis by the COMSTAT program of four variables describing biofilm structure - mean thickness, roughness, substratum coverage and surface to volume ratio - showed that the four Pseudomonas: strains represent different modes of biofilm growth. P. putida had a unique developmental pattern starting with single cells on the substratum growing into micro-colonies, which were eventually succeeded by long filaments and elongated cell clusters. P. aeruginosa colonized the entire substratum, and formed flat, uniform biofilms. P. aureofaciens resembled P. aeruginosa, but had a stronger tendency to form micro-colonies. Finally, the biofilm structures of P. fluorescens had a phenotype intermediate between those of P. putida and P. aureofaciens. Analysis of biofilms of P. aureofaciens growing on 0.03 mM, 0.1 mM or 0.5 mM citrate minimal media showed that mean biofilm thickness increased with increasing citrate concentration. Moreover, biofilm roughness increased with lower citrate concentrations, whereas surface to volume ratio increased with higher citrate concentrations.
        Bookmark
        • Record: found
        • Abstract: found
        • Article: not found

        Microbial heavy-metal resistance.

        We are just beginning to understand the metabolism of heavy metals and to use their metabolic functions in biotechnology, although heavy metals comprise the major part of the elements in the periodic table. Because they can form complex compounds, some heavy metal ions are essential trace elements, but, essential or not, most heavy metals are toxic at higher concentrations. This review describes the workings of known metal-resistance systems in microorganisms. After an account of the basic principles of homoeostasis for all heavy-metal ions, the transport of the 17 most important (heavy metal) elements is compared.
          Bookmark
          • Record: found
          • Abstract: found
          • Article: not found

          Legionella and Legionnaires' disease: 25 years of investigation.

          There is still a low level of clinical awareness regarding Legionnaires' disease 25 years after it was first detected. The causative agents, legionellae, are freshwater bacteria with a fascinating ecology. These bacteria are intracellular pathogens of freshwater protozoa and utilize a similar mechanism to infect human phagocytic cells. There have been major advances in delineating the pathogenesis of legionellae through the identification of genes which allow the organism to bypass the endocytic pathways of both protozoan and human cells. Other bacteria that may share this novel infectious process are Coxiella burnetti and Brucella spp. More than 40 species and numerous serogroups of legionellae have been identified. Most diagnostic tests are directed at the species that causes most of the reported human cases of legionellosis, L. pneumophila serogroup 1. For this reason, information on the incidence of human respiratory disease attributable to other species and serogroups of legionellae is lacking. Improvements in diagnostic tests such as the urine antigen assay have inadvertently caused a decrease in the use of culture to detect infection, resulting in incomplete surveillance for legionellosis. Large, focal outbreaks of Legionnaires' disease continue to occur worldwide, and there is a critical need for surveillance for travel-related legionellosis in the United States. There is optimism that newly developed guidelines and water treatment practices can greatly reduce the incidence of this preventable illness.
            Bookmark

            Author and article information

            Affiliations
            [1 ]Department of Biological Sciences, Clemson University, Clemson, South Carolina, United States of America
            [2 ]Clemson Light Imaging Facility, Clemson University, Clemson, South Carolina, United States of America
            Purdue University, UNITED STATES
            Author notes

            Competing Interests: The authors have declared that no competing interests exist.

            • Conceptualization: CW T. Bruce TM.

            • Data curation: CW T. Banks TM.

            • Formal analysis: KJ CW TM.

            • Funding acquisition: TM.

            • Investigation: KJ CW T. Banks JR T. Bruce.

            • Methodology: T. Bruce TM.

            • Project administration: TM.

            • Resources: CW T. Bruce TM.

            • Supervision: T. Bruce TM.

            • Validation: KJ TM.

            • Visualization: CW TM.

            • Writing – original draft: KJ CW JR T. Bruce TM.

            • Writing – review & editing: KJ CW T. Bruce JR T. Banks TM.

            Contributors
            Role: Editor
            Journal
            PLoS One
            PLoS ONE
            plos
            plosone
            PLoS ONE
            Public Library of Science (San Francisco, CA USA )
            1932-6203
            2 May 2017
            2017
            : 12
            : 5
            28463986 5413113 10.1371/journal.pone.0174245 PONE-D-16-16574

            This is an open access article, free of all copyright, and may be freely reproduced, distributed, transmitted, modified, built upon, or otherwise used by anyone for any lawful purpose. The work is made available under the Creative Commons CC0 public domain dedication.

            Counts
            Figures: 8, Tables: 2, Pages: 17
            Product
            Funding
            Funded by: Clemson University (US)
            Award ID: Creative Inquiry Program
            Award Recipient :
            Clemson University Creative Inquiry Program provided funding through JR and TB participation in the project.
            Categories
            Research Article
            Biology and Life Sciences
            Organisms
            Bacteria
            Legionella
            Legionella Pneumophila
            Biology and Life Sciences
            Microbiology
            Medical Microbiology
            Microbial Pathogens
            Bacterial Pathogens
            Legionella
            Legionella Pneumophila
            Medicine and Health Sciences
            Pathology and Laboratory Medicine
            Pathogens
            Microbial Pathogens
            Bacterial Pathogens
            Legionella
            Legionella Pneumophila
            Biology and Life Sciences
            Genetics
            DNA
            Operons
            Biology and Life Sciences
            Biochemistry
            Nucleic Acids
            DNA
            Operons
            Biology and Life Sciences
            Microbiology
            Bacteriology
            Bacterial Biofilms
            Biology and Life Sciences
            Microbiology
            Biofilms
            Bacterial Biofilms
            Biology and Life Sciences
            Organisms
            Bacteria
            Legionella
            Biology and Life Sciences
            Microbiology
            Medical Microbiology
            Microbial Pathogens
            Bacterial Pathogens
            Legionella
            Medicine and Health Sciences
            Pathology and Laboratory Medicine
            Pathogens
            Microbial Pathogens
            Bacterial Pathogens
            Legionella
            Biology and Life Sciences
            Microbiology
            Biofilms
            Biology and Life Sciences
            Cell Biology
            Cellular Structures and Organelles
            Cell Membranes
            Membrane Proteins
            Integral Membrane Proteins
            Biology and life sciences
            Biochemistry
            Proteins
            DNA-binding proteins
            Physical Sciences
            Chemistry
            Chemical Elements
            Gold
            Custom metadata
            All relevant data are within the paper.

            Uncategorized

            Comments

            Comment on this article