scholarly journals Prey range and genome evolution ofHalobacteriovorax marinuspredatory bacteria from an estuary

2017 ◽  
Author(s):  
Brett G. Enos ◽  
Molly K. Anthony ◽  
Joseph A. DeGiorgis ◽  
Laura E. Williams
Keyword(s):  
Gene Transfer ◽  
Horizontal Gene Transfer ◽  
Codon Usage ◽  
Genome Evolution ◽  
Genome Analysis ◽  
Regulation Of Gene Expression ◽  
Gram Negative Bacteria ◽  
Gram Negative ◽  
Predatory Bacteria ◽  
The Impact

AbstractBackgroundHalobacteriovoraxare saltwater-adapted predatory bacteria that attack Gram-negative bacteria and therefore may play an important role in shaping microbial communities. To understand the impact ofHalobacteriovoraxon ecosystems and develop them as biocontrol agents, it is important to characterize variation in predation phenotypes such as prey range and investigate the forces impactingHalobacteriovoraxgenome evolution across different phylogenetic distances.ResultsWe isolatedH. marinusBE01 from an estuary in Rhode Island usingVibriofrom the same site as prey. Small, fast-moving attack phase BE01 cells attach to and invade prey cells, consistent with the intraperiplasmic predation strategy ofH. marinustype strain SJ. BE01 is a prey generalist, forming plaques onVibriostrains from the estuary as well asPseudomonasfrom soil andE. coli. Genome analysis revealed that BE01 is very closely related to SJ, with extremely high conservation of gene order and amino acid sequences. Despite this similarity, we identified two regions of gene content difference that likely resulted from horizontal gene transfer. Analysis of modal codon usage frequencies supports the hypothesis that these regions were acquired from bacteria with different codon usage biases compared toHalobacteriovorax. In BE01, one of these regions includes genes associated with mobile genetic elements, such as a transposase not found in SJ and degraded remnants of an integrase occurring as a full-length gene in SJ. The corresponding region in SJ included unique mobile genetic element genes, such as a site-specific recombinase and bacteriophage-related genes not found in BE01. Acquired functions in BE01 include thedndoperon, which encodes a pathway for DNA modification that may protect DNA from nucleases, and a suite of genes involved in membrane synthesis and regulation of gene expression that was likely acquired from anotherHalobacteriovoraxlineage.ConclusionsOur results support previous observations thatHalobacteriovoraxprey on a broad range of Gram-negative bacteria. Genome analysis suggests strong selective pressure to maintain the genome in theH. marinuslineage represented by BE01 and SJ, although our results also provide further evidence that horizontal gene transfer plays an important role in genome evolution in predatory bacteria.

Type III Secretion: More Systems Than You Think

Physiology ◽  
2005 ◽  
Vol 20 (5) ◽  
pp. 326-339 ◽  
Author(s):  
Paul Troisfontaines ◽  
Guy R. Cornelis
Keyword(s):  
Gene Transfer ◽  
Horizontal Gene Transfer ◽  
Type Iii Secretion ◽  
Plant Cells ◽  
Effector Proteins ◽  
Eukaryotic Cells ◽  
Gram Negative Bacteria ◽  
Gram Negative ◽  
Type Iii ◽  
Target Animal

The type III secretion (T3S) pathway allows bacteria to inject effector proteins into the cytosol of target animal or plant cells. T3S systems evolved into seven families that were distributed among Gram-negative bacteria by horizontal gene transfer. There are probably a few hundred effectors interfering with control and signaling in eukaryotic cells and offering a wealth of new tools to cell biologists.

Integron Class 1 Reservoir among Highly Resistant Gram-Negative Microorganisms Recovered at a Dutch Teaching Hospital

2009 ◽  
Vol 30 (10) ◽  
pp. 1015-1018 ◽  
Author(s):  
Marlies J. Mooij ◽  
Ina Willemsen ◽  
Marihe Lobbrecht ◽  
Christina Vandenbroucke-Grauls ◽  
Jan Kluytmans ◽  
...  
Keyword(s):  
Gene Transfer ◽  
Horizontal Gene Transfer ◽  
Resistance Genes ◽  
Tertiary Care Hospital ◽  
Tertiary Care ◽  
Gram Negative Bacteria ◽  
Care Hospital ◽  
Gram Negative ◽  
Class 1 ◽  
Cross Transmission

Integrons play an important role in the dissemination of resistance genes among bacteria. Nearly 70% of highly resistant gram-negative bacteria isolated at a tertiary care hospital harbored an integron. Epidemiologic analysis suggests that horizontal gene transfer is an important mechanism of resistance spread and has a greater contribution than cross-transmission to levels of resistance in settings where highly resistant gram-negative bacteria are endemic.

scholarly journals Mobilization of Plasmids and Chromosomal DNA Mediated by the SXT Element, a Constin Found in Vibrio cholerae O139

2000 ◽  
Vol 182 (7) ◽  
pp. 2043-2047 ◽  
Author(s):  
Bianca Hochhut ◽  
Joeli Marrero ◽  
Matthew K. Waldor
Keyword(s):  
Gene Transfer ◽  
Horizontal Gene Transfer ◽  
Vibrio Cholerae ◽  
Gram Negative Bacteria ◽  
Chromosomal Dna ◽  
General Role ◽  
Gram Negative ◽  
Vibrio Cholerae O139 ◽  
Multiple Antibiotics

ABSTRACT The Vibrio cholerae SXT element encodes resistance to multiple antibiotics and is a conjugative, self-transmissible, and chromosomally integrating element (a constin). Excision and self-transfer of the SXT element require an element-encoded integrase. We now report that the SXT element can also mobilize the plasmids RSF1010 and CloDF13 in trans as well as chromosomal DNA in an Hfr-like manner. SXT element-mediated mobilization of plasmids and chromosomal DNA, unlike its self-transfer, is not dependent upon excision of the element from the chromosome. These results raise the possibility that the SXT element and other constins play a general role in horizontal gene transfer among gram-negative bacteria.

scholarly journals IS 1294 Reorganizes Plasmids in a Multidrug-Resistant Escherichia coli Strain

2021 ◽  
Author(s):  
Yushan Pan ◽  
Tengli Zhang ◽  
Lijie Yu ◽  
Zhiyong Zong ◽  
Shiyu Zhao ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Antibiotic Resistance ◽  
Gene Transfer ◽  
Horizontal Gene Transfer ◽  
16S Rrna ◽  
Multidrug Resistant ◽  
Coli Strain ◽  
Gram Negative Bacteria ◽  
Gram Negative ◽  
16S Rrna Methylase

The increasing resistance to β-lactams and aminoglycoside antibiotics, mainly due to extended-spectrum β-lactamases (ESBLs) and 16S rRNA methylase genes, is becoming a serious problem in Gram-negative bacteria. Plasmids, as the vehicles for resistance gene capture and horizontal gene transfer, serve a key role in terms of antibiotic resistance emergence and transmission.

scholarly journals Incorporation of Plasmid DNA Into Bacterial Membrane Vesicles by Peptidoglycan Defects in Escherichia coli

2021 ◽  
Vol 12 ◽  
Author(s):  
Sharmin Aktar ◽  
Yuhi Okamoto ◽  
So Ueno ◽  
Yuhei O. Tahara ◽  
Masayoshi Imaizumi ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Gene Transfer ◽  
Horizontal Gene Transfer ◽  
Outer Membrane ◽  
Membrane Vesicles ◽  
Outer Membrane Vesicles ◽  
Bacterial Membrane ◽  
Gram Negative Bacteria ◽  
Plasmid Copy ◽  
Gram Negative

Membrane vesicles (MVs) are released by various prokaryotes and play a role in the delivery of various cell-cell interaction factors. Recent studies have determined that these vesicles are capable of functioning as mediators of horizontal gene transfer. Outer membrane vesicles (OMVs) are a type of MV that is released by Gram-negative bacteria and primarily composed of outer membrane and periplasm components; however, it remains largely unknown why DNA is contained within OMVs. Our study aimed to understand the mechanism by which DNA that is localized in the cytoplasm is incorporated into OMVs in Gram-negative bacteria. We compared DNA associated with OMVs using Escherichia coli BW25113 cells harboring the non-conjugative, non-mobilized, and high-copy plasmid pUC19 and its hypervesiculating mutants that included ΔnlpI, ΔrseA, and ΔtolA. Plasmid copy per vesicle was increased in OMVs derived from ΔnlpI, in which peptidoglycan (PG) breakdown and synthesis are altered. When supplemented with 1% glycine to inhibit PG synthesis, both OMV formation and plasmid copy per vesicle were increased in the wild type. The bacterial membrane condition test indicated that membrane permeability was increased in the presence of glycine at the late exponential phase, in which cell lysis did not occur. Additionally, quick-freeze deep-etch and replica electron microscopy observations revealed that outer-inner membrane vesicles (O-IMVs) are formed in the presence of glycine. Thus, two proposed routes for DNA incorporation into OMVs under PG-damaged conditions are suggested. These routes include DNA leakage due to increased membrane permeation and O-IMV formation. Additionally, our findings contribute to a greater understanding of the vesicle-mediated horizontal gene transfer that occurs in nature and the utilization of MVs for DNA cargo.

scholarly journals Variation in genome content and predatory phenotypes betweenBdellovibriosp. NC01 isolated from soil andB. bacteriovorustype strain HD100

2019 ◽  
Author(s):  
Laura E. Williams ◽  
Nicole Cullen ◽  
Joseph A. DeGiorgis ◽  
Karla J. Martinez ◽  
Justina Mellone ◽  
...  
Keyword(s):  
Horizontal Gene Transfer ◽  
Type Strain ◽  
Bacterial Infections ◽  
Clinical Applications ◽  
Gram Negative Bacteria ◽  
Ecological Significance ◽  
Gram Negative ◽  
E Coli ◽  
Predatory Bacteria ◽  
Genome Content

AbstractThe range of naturally occurring variation in the ability ofBdellovibriostrains to attack and kill Gram-negative bacteria is not well understood. Defining phenotypic and associated genotypic variation amongBdellovibriowill clarify how divergent lineages within this genus impact microbial communities and will inform development of predatory bacteria as biocontrol agents to combat bacterial infections. We isolatedBdellovibriosp. NC01 from soil and compared its genome and predatory phenotypes toB. bacteriovorustype strain HD100. Based on analysis of 16S rRNA gene sequences and average amino acid identity, NC01 belongs to a different species than HD100. Genome-wide comparisons and individual gene analyses indicated that eight NC01 genome regions were likely acquired by horizontal gene transfer (HGT), further supporting an important role for HGT inBdellovibriogenome evolution. Within these regions, multiple protein-coding sequences were assigned predicted functions related to transcriptional regulation and transport; however, most were annotated as hypothetical proteins. Compared to HD100, NC01 has a limited prey range and killsE. coliML35 less efficiently. Whereas HD100 drastically reduces the ML35 population and then maintains low prey population density, NC01 causes a smaller reduction in ML35, after which the prey population recovers, accompanied by a decrease in NC01. In addition, NC01 forms turbid plaques on lawns of ML35, in contrast to clear plaques formed by HD100. Characterizing variation in interactions betweenBdellovibrioand Gram-negative bacteria, such as observed with NC01 and HD100, is important for understanding the ecological significance of predatory bacteria and evaluating their effectiveness in clinical applications.ImportanceBdellovibrioattack and kill Gram-negative bacteria; however, not allBdellovibriostrains are equally efficient at killing the same Gram-negative bacteria. Defining howBdellovibriovary in predatory phenotypes and how this phenotypic variation relates to differences in genotype is important for understanding the ecological significance of predatory bacteria and evaluating their effectiveness in biocontrol of bacterial infections. We determined variation in genome content and predatory phenotypes, including prey range and predation efficiency, betweenBdellovibriosp. NC01 isolated from soil andB. bacteriovorustype strain HD100. NC01 is phylogenetically divergent from HD100, with eight regions of unique gene content likely acquired by horizontal gene transfer. Compared to HD100, the prey range of NC01 is limited, and it was less efficient at killing a strain ofE. coli. These differences may have important implications for how each strain impacts microbial communities in different environments and for the effectiveness of each in clinical applications.

Mechanisms of DNA Uptake by Naturally Competent Bacteria

2019 ◽  
Vol 53 (1) ◽  
pp. 217-237 ◽  
Author(s):  
David Dubnau ◽  
Melanie Blokesch
Keyword(s):  
Gene Transfer ◽  
Horizontal Gene Transfer ◽  
Outer Membrane ◽  
Growth Arrest ◽  
Dna Binding Protein ◽  
Gram Negative Bacteria ◽  
Dna Uptake ◽  
Gram Negative ◽  
Gram Positive Bacteria ◽  
Proton Symport

Transformation is a widespread mechanism of horizontal gene transfer in bacteria. DNA uptake to the periplasmic compartment requires a DNA-uptake pilus and the DNA-binding protein ComEA. In the gram-negative bacteria, DNA is first pulled toward the outer membrane by retraction of the pilus and then taken up by binding to periplasmic ComEA, acting as a Brownian ratchet to prevent backward diffusion. A similar mechanism probably operates in the gram-positive bacteria as well, but these systems have been less well characterized. Transport, defined as movement of a single strand of transforming DNA to the cytosol, requires the channel protein ComEC. Although less is understood about this process, it may be driven by proton symport. In this review we also describe various phenomena that are coordinated with the expression of competence for transformation, such as fratricide, the kin-discriminatory killing of neighboring cells, and competence-mediated growth arrest.

scholarly journals Gene Transfer Potential of Outer Membrane Vesicles of Gram-Negative Bacteria

2021 ◽  
Vol 22 (11) ◽  
pp. 5985
Author(s):  
Federica Dell’Annunziata ◽  
Veronica Folliero ◽  
Rosa Giugliano ◽  
Anna De Filippis ◽  
Cristina Santarcangelo ◽  
...  
Keyword(s):  
Gene Transfer ◽  
Horizontal Gene Transfer ◽  
Outer Membrane ◽  
Pathogenic Bacteria ◽  
Membrane Vesicles ◽  
Multidrug Resistant ◽  
Outer Membrane Vesicles ◽  
Biologically Active ◽  
Gram Negative Bacteria ◽  
Gram Negative

The increasing spread of multidrug-resistant pathogenic bacteria is one of the major threats to public health worldwide. Bacteria can acquire antibiotic resistance and virulence genes through horizontal gene transfer (HGT). A novel horizontal gene transfer mechanism mediated by outer membrane vesicles (OMVs) has been recently identified. OMVs are rounded nanostructures released during their growth by Gram-negative bacteria. Biologically active toxins and virulence factors are often entrapped within these vesicles that behave as molecular carriers. Recently, OMVs have been reported to contain DNA molecules, but little is known about the vesicle packaging, release, and transfer mechanisms. The present review highlights the role of OMVs in HGT processes in Gram-negative bacteria.

scholarly journals Shadowing the Actions of a Predator: Backlit Fluorescent Microscopy Reveals Synchronous Nonbinary Septation of Predatory Bdellovibrio inside Prey and Exit through Discrete Bdelloplast Pores

2010 ◽  
Vol 192 (24) ◽  
pp. 6329-6335 ◽  
Author(s):  
A. K. Fenton ◽  
M. Kanna ◽  
R. D. Woods ◽  
S.-I. Aizawa ◽  
R. E. Sockett
Keyword(s):  
Cell Division ◽  
Outer Membrane ◽  
Fluorescent Microscopy ◽  
Gram Negative Bacteria ◽  
Bacterial Cell Division ◽  
Prey Cell ◽  
Gram Negative ◽  
A Genome ◽  
Predatory Bacteria ◽  
First Time

ABSTRACT The Bdellovibrio are miniature “living antibiotic” predatory bacteria which invade, reseal, and digest other larger Gram-negative bacteria, including pathogens. Nutrients for the replication of Bdellovibrio bacteria come entirely from the digestion of the single invaded bacterium, now called a bdelloplast, which is bound by the original prey outer membrane. Bdellovibrio bacteria are efficient digesters of prey cells, yielding on average 4 to 6 progeny from digestion of a single prey cell of a genome size similar to that of the Bdellovibrio cell itself. The developmental intrabacterial cycle of Bdellovibrio is largely unknown and has never been visualized “live.” Using the latest motorized xy stage with a very defined z-axis control and engineered periplasmically fluorescent prey allows, for the first time, accurate return and visualization without prey bleaching of developing Bdellovibrio cells using solely the inner resources of a prey cell over several hours. We show that Bdellovibrio bacteria do not follow the familiar pattern of bacterial cell division by binary fission. Instead, they septate synchronously to produce both odd and even numbers of progeny, even when two separate Bdellovibrio cells have invaded and develop within a single prey bacterium, producing two different amounts of progeny. Evolution of this novel septation pattern, allowing odd progeny yields, allows optimal use of the finite prey cell resources to produce maximal replicated, predatory bacteria. When replication is complete, Bdellovibrio cells exit the exhausted prey and are seen leaving via discrete pores rather than by breakdown of the entire outer membrane of the prey.

Sign in / Sign up

Export Citation Format

Share Document