scholarly journals Characterization of htrB and msbB Mutants of the Light Organ Symbiont Vibrio fischeri

2007 ◽  
Vol 74 (3) ◽  
pp. 633-644 ◽  
Author(s):  
Dawn M. Adin ◽  
Nancy J. Phillips ◽  
Bradford W. Gibson ◽  
Michael A. Apicella ◽  
Edward G. Ruby ◽  
...  
Keyword(s):  
Lipid A ◽  
Vibrio Fischeri ◽  
Sodium Dodecyl ◽  
Chromosome 1 ◽  
Chromosome 2 ◽  
Euprymna Scolopes ◽  
Host Interactions ◽  
Lipid A Structure ◽  
Bacterial Lipid

ABSTRACT Bacterial lipid A is an important mediator of bacterium-host interactions, and secondary acylations added by HtrB and MsbB can be critical for colonization and virulence in pathogenic infections. In contrast, Vibrio fischeri lipid A stimulates normal developmental processes in this bacterium's mutualistic host, Euprymna scolopes, although the importance of lipid A structure in this symbiosis is unknown. To further examine V. fischeri lipid A and its symbiotic function, we identified two paralogs of htrB (designated htrB1 and htrB2) and an msbB gene in V. fischeri ES114 and demonstrated that these genes encode lipid A secondary acyltransferases. htrB2 and msbB are found on the Vibrio “housekeeping” chromosome 1 and are conserved in other Vibrio species. Mutations in htrB2 and msbB did not impair symbiotic colonization but resulted in phenotypic alterations in culture, including reduced motility and increased luminescence. These mutations also affected sensitivity to sodium dodecyl sulfate, kanamycin, and polymyxin, consistent with changes in membrane permeability. Conversely, htrB1 is located on the smaller, more variable vibrio chromosome 2, and an htrB1 mutant was wild-type-like in culture but appeared attenuated in initiating the symbiosis and was outcompeted 2.7-fold during colonization when mixed with the parent. These data suggest that htrB2 and msbB play conserved general roles in vibrio biology, whereas htrB1 plays a more symbiosis-specific role in V. fischeri.

scholarly journals An Expanded Transposon Mutant Library Reveals that Vibrio fischeri δ-Aminolevulinate Auxotrophs Can Colonize Euprymna scolopes

2016 ◽  
Vol 83 (5) ◽  
Author(s):  
Noreen L. Lyell ◽  
Alecia N. Septer ◽  
Anne K. Dunn ◽  
Drew Duckett ◽  
Julie L. Stoudenmire ◽  
...  
Keyword(s):  
Vibrio Fischeri ◽  
Light Organ ◽  
Mutant Library ◽  
Euprymna Scolopes ◽  
Simple Method ◽  
Content Type ◽  
Transposon Insertion ◽  
Rich Media ◽  
Show Evidence

ABSTRACT Libraries of defined mutants are valuable research tools but necessarily lack gene knockouts that are lethal under the conditions used in library construction. In this study, we augmented a Vibrio fischeri mutant library generated on a rich medium (LBS, which contains [per liter] 10 g of tryptone, 5 g of yeast extract, 20 g of NaCl, and 50 mM Tris [pH 7.5]) by selecting transposon insertion mutants on supplemented LBS and screening for those unable to grow on LBS. We isolated strains with insertions in alr, glr (murI), glmS, several heme biosynthesis genes, and ftsA, as well as a mutant disrupted 14 bp upstream of ftsQ. Mutants with insertions in ftsA or upstream of ftsQ were recovered by addition of Mg2+ to LBS, but their cell morphology and motility were affected. The ftsA mutant was more strongly affected and formed cells or chains of cells that appeared to wind back on themselves helically. Growth of mutants with insertions in glmS, alr, or glr was recovered with N-acetylglucosamine (NAG), d-alanine, or d-glutamate, respectively. We hypothesized that NAG, d-alanine, or d-glutamate might be available to V. fischeri in the Euprymna scolopes light organ; however, none of these mutants colonized the host effectively. In contrast, hemA and hemL mutants, which are auxotrophic for δ-aminolevulinate (ALA), colonized at wild-type levels, although mutants later in the heme biosynthetic pathway were severely impaired or unable to colonize. Our findings parallel observations that legume hosts provide Bradyrhizobium symbionts with ALA, but they contrast with virulence phenotypes of hemA mutants in some pathogens. The results further inform our understanding of the symbiotic light organ environment. IMPORTANCE By supplementing a rich yeast-based medium, we were able to recover V. fischeri mutants with insertions in conditionally essential genes, and further characterization of these mutants provided new insights into this bacterium's symbiotic environment. Most notably, we show evidence that the squid host can provide V. fischeri with enough ALA to support its growth in the light organ, paralleling the finding that legumes provide Bradyrhizobium ALA in symbiotic nodules. Taken together, our results show how a simple method of augmenting already rich media can expand the reach and utility of defined mutant libraries.

scholarly journals Symbiotic Characterization of Vibrio fischeri ES114 Mutants That Display Enhanced Luminescence in Culture

2013 ◽  
Vol 79 (7) ◽  
pp. 2480-2483 ◽  
Author(s):  
Noreen L. Lyell ◽  
Eric V. Stabb
Keyword(s):  
Vibrio Fischeri ◽  
Euprymna Scolopes ◽  
Content Type ◽  
Host Environment ◽  
Enhanced Luminescence

ABSTRACTVibrio fischeriES114 is a bioluminescent symbiont of the squidEuprymna scolopes. Like most isolates fromE. scolopes, ES114 produces only dim luminescence outside the host, even in dense cultures. We previously identified mutants with brighter luminescence, and here we report their symbiotic phenotypes, providing insights into the host environment.

scholarly journals Characterization of the Vibrio fischeri Fatty Acid Chemoreceptors, VfcB and VfcB2

2015 ◽  
Vol 82 (2) ◽  
pp. 696-704 ◽  
Author(s):  
K. Nikolakakis ◽  
K. Monfils ◽  
S. Moriano-Gutierrez ◽  
C. A. Brennan ◽  
E. G. Ruby
Keyword(s):  
Fatty Acids ◽  
Fatty Acid ◽  
Vibrio Fischeri ◽  
Euprymna Scolopes ◽  
Content Type ◽  
The Family ◽  
Ligand Interactions ◽  
Chemotaxis Proteins ◽  
Large Repertoire

ABSTRACTBacteria use a wide variety of methyl-accepting chemotaxis proteins (MCPs) to mediate their attraction to or repulsion from different chemical signals in their environment. The bioluminescent marine bacteriumVibrio fischeriis the monospecific symbiont of the Hawaiian bobtail squid,Euprymna scolopes, and encodes a large repertoire of MCPs that are hypothesized to be used during different parts of its complex, multistage lifestyle. Here, we report the initial characterization of two such MCPs fromV. fischerithat are responsible for mediating migration toward short- and medium-chain aliphatic (or fatty) acids. These receptors appear to be distributed among only members of the familyVibrionaceaeand are likely descended from a receptor that has been lost by the majority of the members of this family. While chemotaxis greatly enhances the efficiency of host colonization byV. fischeri, fatty acids do not appear to be used as a chemical cue during this stage of the symbiosis. This study presents an example of straight-chain fatty acid chemoattraction and contributes to the growing body of characterized MCP-ligand interactions.

Isolation and characterization of a visibly luminous variant of Vibrio fischeri strain ES114 from the sepiolid squid Euprymna scolopes

1995 ◽  
Vol 164 (3) ◽  
pp. 194-202 ◽  
Author(s):  
P. V. Dunlap ◽  
Kumiko Kita-Tsukamoto ◽  
John B. Waterbury ◽  
Sean M. Callahan
Keyword(s):  
Vibrio Fischeri ◽  
Euprymna Scolopes ◽  
Isolation And Characterization ◽  
Sepiolid Squid

scholarly journals Insights into flagellar function and mechanism from the squid–vibrio symbiosis

2019 ◽  
Vol 5 (1) ◽  
Author(s):  
Marie-Stephanie Aschtgen ◽  
Caitlin A. Brennan ◽  
Kiel Nikolakakis ◽  
Stephanie Cohen ◽  
Margaret McFall-Ngai ◽  
...  
Keyword(s):  
Biofilm Formation ◽  
Vibrio Fischeri ◽  
Complex Problem ◽  
Multiple Roles ◽  
Euprymna Scolopes ◽  
Host Interactions ◽  
Bacterial Flagella ◽  
Unique Model ◽  
The Many ◽  
Structure Assembly

Abstract Flagella are essential and multifunctional nanomachines that not only move symbionts towards their tissue colonization site, but also play multiple roles in communicating with the host. Thus, untangling the activities of flagella in reaching, interacting, and signaling the host, as well as in biofilm formation and the establishment of a persistent colonization, is a complex problem. The squid–vibrio system offers a unique model to study the many ways that bacterial flagella can influence a beneficial association and, generally, other bacteria–host interactions. Vibrio fischeri is a bioluminescent bacterium that colonizes the Hawaiian bobtail squid, Euprymna scolopes. Over the last 15 years, the structure, assembly, and functions of V. fischeri flagella, including not only motility and chemotaxis, but also biofilm formation and symbiotic signaling, have been revealed. Here we discuss these discoveries in the perspective of other host–bacteria interactions.

Electron Microscope Study of RNA's of Paramyxoviruses

1972 ◽  
Vol 30 ◽  
pp. 196-197
Author(s):  
Ruchama Baum ◽  
J.T. Seto
Keyword(s):  
Electron Microscopy ◽  
Electron Microscope ◽  
Electron Microscope Study ◽  
Sendai Virus ◽  
Sodium Dodecyl ◽  
Rna Molecules ◽  
Virus Particles ◽  
Molecular Weights ◽  
Length Measurements

The ribonucleic acid (RNA) of paramyxoviruses has been characterized by biochemical and physiochemical methods. However, paramyxovirus RNA molecules have not been studied by electron microscopy. The molecular weights of these single-stranded viral RNA molecules are not known as yet. Since electron microscopy has been found to be useful for the characterization of single-stranded RNA, this investigation was initiated to examine the morphology and length measurements of paramyxovirus RNA's.Sendai virus Z strain and Newcastle disease virus (NDV), Milano strain, were used. For these studies it was necessary to develop a method of extracting RNA molecules from purified virus particles. Highly purified Sendai virus was treated with pronase (300 μg/ml) at 37°C for 30 minutes and the RNA extracted by the sodium dodecyl sulfate (SDS)-phenol procedure.

scholarly journals Reduction of endotoxicity in Bordetella bronchiseptica by lipid A engineering: Characterization of lpxL1 and pagP mutants

Virulence ◽  
2021 ◽  
Vol 12 (1) ◽  
pp. 1452-1468
Author(s):  
Jesús Pérez-Ortega ◽  
Roel M. Van Harten ◽  
Ria Van Boxtel ◽  
Michel Plisnier ◽  
Marc Louckx ◽  
...  
Keyword(s):  
Lipid A ◽  
Bordetella Bronchiseptica

scholarly journals Isolation and Characterization Of Rice R Genes: Evidence for Distinct Evolutionary Paths in Rice and Maize

Genetics ◽  
1996 ◽  
Vol 142 (3) ◽  
pp. 1021-1031 ◽  
Author(s):  
Jianping Hu ◽  
Beth Anderson ◽  
Susan R Wessler
Keyword(s):  
Gene Family ◽  
Gene Families ◽  
Chromosome 1 ◽  
R Gene ◽  
R Genes ◽  
Helix Loop Helix ◽  
Isolation And Characterization ◽  
Undetermined Function ◽  
Evolutionary Paths

Abstract R and B genes and their homologues encode basic helix-loop-helix (bHLH) transcriptional activators that regulate the anthocyanin biosynthetic pathway in flowering plants. In maize, R/B genes comprise a very small gene family whose organization reflects the unique evolutionary history and genome architecture of maize. To know whether the organization of the R gene family could provide information about the origins of the distantly related grass rice, we characterized members of the R gene family from rice Oryza sativa. Despite being a true diploid, O. sativa has at least two R genes. An active homologue (Ra) with extensive homology with other R genes is located at a position on chromosome 4 previously shown to be in synteny with regions of maize chromosomes 2 and 10 that contain the B and R loci, respectively. A second rice R gene (Rb) of undetermined function was identified on chromosome 1 and found to be present only in rice species with AA genomes. All non-AA species have but one R gene that is Ra-like. These data suggest that the common ancestor shared by maize and rice had a single R gene and that the small R gene families of grasses have arisen recently and independently.

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