scholarly journals Longitudinal study of vinyl chloride degrading Dehalococcoides mccartyi-containing cultures to promote horizontal gene transfer

2020 ◽  
Author(s):  
Nadia Morson ◽  
Olivia Molenda ◽  
Katherine J. Picott ◽  
Ruth E. Richardson ◽  
Elizabeth A. Edwards
Keyword(s):  
Gene Transfer ◽  
Horizontal Gene Transfer ◽  
Vinyl Chloride ◽  
Nitrogen Sources ◽  
Recipient Strain ◽  
Gene Encoding ◽  
Genetic Transfer ◽  
Dehalococcoides Mccartyi ◽  
Chlorinated Solvent ◽  
Multiple Strains

ABSTRACTVinyl chloride (VC) is a human carcinogen that accumulates in soil and groundwater due to incomplete dechlorination of chlorinated ethenes. Some strains of obligate organohalide respiring Dehalococcoides mccartyi can synthesize the VC reductase that catalyzes the dechlorination of VC to ethene. The gene encoding the VC reductase, vcrA, is found on a mobile genetic element called the vcrA-Genomic Island (GI) that may participate in horizontal gene transfer. We designed an experiment to try to induce horizontal gene transfer of the vcrA-GI by mixing two enrichment cultures: one containing the donor D. mccartyi strain with the vcrA-GI that could not fix nitrogen and the second containing the recipient strain devoid of the vcrA-GI that could fix nitrogen. Therefore, mixing the two cultures in medium without ammonium while providing VC as the sole electron acceptor was hypothesized to select for a mutant strain of D. mccartyi that could both fix nitrogen and respire VC. However, after over 4 years of incubation, no evidence for horizontal gene transfer of the vcrA-GI was found. Rather, we observed VC-dechlorinating activity attributed to the TCE reductase, TceA, in the recipient strain. We also observed that D. mccartyi can grow by scavenging low concentrations of fixed nitrogen sources. During this experiment we identified two additional D. mccartyi strains in the KB-1 TCE-enriched culture that could fix nitrogen. The presence of multiple strains of D. mccartyi with distinct phenotypes may enhance bioaugmentation success, but here it may have undermined attempts to force horizontal gene transfer of the vcrA-GI.IMPORTANCEDehalococcoides mccartyi are a powerful bioremediation tool for the degradation of chlorinated solvent contamination in soil and groundwater. Only a few D. mccartyi strains have the ability to dechlorinate toxic chlorinated compounds like vinyl chloride. Interestingly, the genetic ability to dechlorinate vinyl chloride is theorized to be shared among D. mccartyi strains. In this study we attempted to promote the genetic transfer of vinyl chloride degrading ability from one D. mccartyi strain to another. Although we did not observe this exchange, our findings suggest there may be restrictions of genetic transfer between specific clades or sub-groups of D. mccartyi strains. Developing our understanding of genetic transfer among D. mccartyi strains could allow for enhanced degradation of chlorinated solvent contamination in situ.

scholarly journals Kin discrimination promotes horizontal gene transfer between unrelated strains in Bacillus subtilis

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Polonca Stefanic ◽  
Katarina Belcijan ◽  
Barbara Kraigher ◽  
Rok Kostanjšek ◽  
Joseph Nesme ◽  
...  
Keyword(s):  
Bacillus Subtilis ◽  
Gene Transfer ◽  
Horizontal Gene Transfer ◽  
Social Interactions ◽  
Recipient Strain ◽  
Donor Strain ◽  
Kin Discrimination ◽  
Defence Mechanisms ◽  
Donor Cells ◽  
Novel Alleles

AbstractBacillus subtilis is a soil bacterium that is competent for natural transformation. Genetically distinct B. subtilis swarms form a boundary upon encounter, resulting in killing of one of the strains. This process is mediated by a fast-evolving kin discrimination (KD) system consisting of cellular attack and defence mechanisms. Here, we show that these swarm antagonisms promote transformation-mediated horizontal gene transfer between strains of low relatedness. Gene transfer between interacting non-kin strains is largely unidirectional, from killed cells of the donor strain to surviving cells of the recipient strain. It is associated with activation of a stress response mediated by sigma factor SigW in the donor cells, and induction of competence in the recipient strain. More closely related strains, which in theory would experience more efficient recombination due to increased sequence homology, do not upregulate transformation upon encounter. This result indicates that social interactions can override mechanistic barriers to horizontal gene transfer. We hypothesize that KD-mediated competence in response to the encounter of distinct neighbouring strains could maximize the probability of efficient incorporation of novel alleles and genes that have proved to function in a genomically and ecologically similar context.

scholarly journals Genomic Islands in the Corynebacterium efficiens Genome

2005 ◽  
Vol 71 (6) ◽  
pp. 3126-3130 ◽  
Author(s):  
Ren Zhang ◽  
Chun-Ting Zhang
Keyword(s):  
Thermal Stability ◽  
Gene Transfer ◽  
Horizontal Gene Transfer ◽  
Genomic Island ◽  
Genomic Islands ◽  
Aspartate Kinase ◽  
Gene Encoding ◽  
Profile Method ◽  
Adaptive Mutations ◽  
Thermal Stability Of

ABSTRACT Corynebacterium efficiens is a gram-positive nonpathogenic bacterium which can grow and produce glutamate at 40°C or above. By using the cumulative GC profile method, we have identified four genomic islands which have many unifying genomic island-specific features in the C. efficiens genome. The presence of the gene encoding an aspartate kinase in a genomic island helps explain the unexpected low thermal stability of this enzyme; i.e., the adaptive mutations have not occurred extensively due to the recent horizontal gene transfer.

scholarly journals Horizontal Gene Transfer of ftsI, Encoding Penicillin-Binding Protein 3, in Haemophilus influenzae

2007 ◽  
Vol 51 (5) ◽  
pp. 1589-1595 ◽  
Author(s):  
Sho Takahata ◽  
Takashi Ida ◽  
Nami Senju ◽  
Yumiko Sanbongi ◽  
Aiko Miyata ◽  
...  
Keyword(s):  
Gene Transfer ◽  
Horizontal Gene Transfer ◽  
Haemophilus Influenzae ◽  
Binding Protein ◽  
Resistant Mutant ◽  
Penicillin Binding Protein ◽  
Genetic Transfer ◽  
Complete Sequences

ABSTRACT Horizontal gene transfer has been identified in only a small number of genes in Haemophilus influenzae, an organism which is naturally competent for transformation. This report provides evidence for the genetic transfer of the ftsI gene, which encodes penicillin-binding protein 3, in H. influenzae. Mosaic structures of the ftsI gene were found in several clinical isolates of H. influenzae. To identify the origin of the mosaic sequence, complete sequences of the corresponding gene from seven type strains of Haemophilus species were determined. Comparison of these sequences with mosaic regions identified a homologous recombination of the ftsI gene between H. influenzae and Haemophilus haemolyticus. Subsequently, ampicillin-resistant H. influenzae strains harboring identical ftsI sequences were genotyped by pulsed-field gel electrophoresis (PFGE). Divergent PFGE patterns among β-lactamase-nonproducing ampicillin-resistant (BLNAR) strains from different hospitals indicated the potential for the genetic transfer of the mutated ftsI gene between these isolates. Moreover, transfer of the ftsI gene from BLNAR strains to β-lactamase-nonproducing ampicillin-susceptible (BLNAS) H. influenzae strains was evaluated in vitro. Coincubation of a BLNAS strain (a rifampin-resistant mutant of strain Rd) and BLNAR strains resulted in the emergence of rifampin- and cefdinir-resistant clones at frequencies of 5.1 × 10−7 to 1.5 × 10−6. Characterization of these doubly resistant mutants by DNA sequencing of the ftsI gene, susceptibility testing, and genotyping by PFGE revealed that the ftsI genes of BLNAR strains had transferred to BLNAS strains during coincubation. In conclusion, horizontal transfer of the ftsI gene in H. influenzae can occur in an intraspecies and an interspecies manner.

scholarly journals Bacillus anthracis Multiplication, Persistence, and Genetic Exchange in the Rhizosphere of Grass Plants

2006 ◽  
Vol 72 (5) ◽  
pp. 3168-3174 ◽  
Author(s):  
Elke Saile ◽  
Theresa M. Koehler
Keyword(s):  
Gene Transfer ◽  
Horizontal Gene Transfer ◽  
Bacillus Anthracis ◽  
Tetracycline Resistance ◽  
Recipient Strain ◽  
Soil Organisms ◽  
Soil System ◽  
Plant Soil ◽  
Close Relatives ◽  
Group Species

ABSTRACT Bacillus anthracis, the causative agent of anthrax, is known for its rapid proliferation and dissemination in mammalian hosts. In contrast, little information exists regarding the lifestyle of this important pathogen outside of the host. Considering that Bacillus species, including close relatives of B. anthracis, are saprophytic soil organisms, we investigated the capacity of B. anthracis spores to germinate in the rhizosphere and to establish populations of vegetative cells that could support horizontal gene transfer in the soil. Using a simple grass plant-soil model system, we show that B. anthracis strains germinate on and around roots, growing in characteristic long filaments. From 2 to 4 days postinoculation, approximately one-half of the B. anthracis CFU recovered from soil containing grass seedlings arose from heat-sensitive organisms, while B. anthracis CFU retrieved from soil without plants consisted of primarily heat-resistant spores. Coinoculation of the plant-soil system with spores of a fertile B. anthracis strain carrying the tetracycline resistance plasmid pBC16 and a selectable B. anthracis recipient strain resulted in transfer of pBC16 from the donor to the recipient as early as 3 days postinoculation. Our findings demonstrate that B. anthracis can survive as a saprophyte outside of the host. The data suggest that horizontal gene transfer in the rhizosphere of grass plants may play a role in the evolution of the Bacillus cereus group species.

scholarly journals TheblpLocus of Streptococcus pneumoniae Plays a Limited Role in the Selection of Strains That Can Cocolonize the Human Nasopharynx

2016 ◽  
Vol 82 (17) ◽  
pp. 5206-5215 ◽  
Author(s):  
Carina Valente ◽  
Suzanne Dawid ◽  
Francisco R. Pinto ◽  
Jason Hinds ◽  
Alexandra S. Simões ◽  
...  
Keyword(s):  
Streptococcus Pneumoniae ◽  
Gene Transfer ◽  
Horizontal Gene Transfer ◽  
Experimental Models ◽  
Nasopharyngeal Colonization ◽  
Content Type ◽  
Limited Role ◽  
Multiple Strains ◽  
The Impact

ABSTRACTNasopharyngeal colonization is important forStreptococcus pneumoniaeevolution, providing the opportunity for horizontal gene transfer when multiple strains co-occur. Although colonization with more than one strain of pneumococcus is common, the factors that influence the ability of strains to coexist are not known. A highly variableblp(bacteriocin-like peptide) locus has been identified in all sequenced strains ofS. pneumoniae. This locus controls the regulation and secretion of bacteriocins, small peptides that target other bacteria. In this study, we analyzed a series of cocolonizing isolates to evaluate the impact of theblplocus on human colonization to determine whether competitive phenotypes of bacteriocin secretion restrict cocolonization. We identified a collection of 135 nasopharyngeal samples cocolonized with two or more strains, totaling 285 isolates. Theblplocus of all strains was characterized genetically with regard to pheromone type, bacteriocin/immunity content, and potential for locus functionality. Inhibitory phenotypes of bacteriocin secretion and locus activity were assessed through overlay assays. Isolates from single colonizations (n= 298) were characterized for comparison. Cocolonizing strains had a high diversity ofblpcassettes; approximately one-third displayed an inhibitory phenotypein vitro. Despitein vitroevidence of competition, pneumococci cocolonized the subjects independently ofblppheromone type (P= 0.577), bacteriocin/immunity content,blplocus activity (P= 0.798), and inhibitory phenotype (P= 0.716). In addition, no significant differences were observed when single and cocolonizing strains were compared. Despite clear evidence ofblp-mediated competition in experimental models, the results of our study suggest that theblplocus plays a limited role in restricting pneumococcal cocolonization in humans.IMPORTANCENasopharyngeal colonization withStreptococcus pneumoniae(pneumococcus) is important for pneumococcal evolution, as the nasopharynx represents the major site for horizontal gene transfer when multiple strains co-occur, a phenomenon known as cocolonization. Understanding how pneumococcal strains interact within the competitive environment of the nasopharynx is of chief importance in the context of pneumococcal ecology. In this study, we used an unbiased collection of naturally co-occurring pneumococcal strains and showed that a biological process frequently used by bacteria for competition—bacteriocin production—is not decisive in the coexistence of pneumococci in the host, in contrast to what has been shown in experimental models.

scholarly journals Comparative Analysis of Three Trypanosomatid Catalases of Different Origin

Antioxidants ◽  
2021 ◽  
Vol 11 (1) ◽  
pp. 46
Author(s):  
Ľubomíra Chmelová ◽  
Claretta Bianchi ◽  
Amanda T. S. Albanaz ◽  
Jana Režnarová ◽  
Richard Wheeler ◽  
...  
Keyword(s):  
Comparative Analysis ◽  
Gene Transfer ◽  
Horizontal Gene Transfer ◽  
Gene Encoding ◽  
Biochemical Analyses ◽  
Cyanide Resistance ◽  
Bacterial Sources ◽  
Bacterial Groups ◽  
Different Origin

Most trypanosomatid flagellates do not have catalase. In the evolution of this group, the gene encoding catalase has been independently acquired at least three times from three different bacterial groups. Here, we demonstrate that the catalase of Vickermania was obtained by horizontal gene transfer from Gammaproteobacteria, extending the list of known bacterial sources of this gene. Comparative biochemical analyses revealed that the enzymes of V. ingenoplastis, Leptomonas pyrrhocoris, and Blastocrithidia sp., representing the three independent catalase-bearing trypanosomatid lineages, have similar properties, except for the unique cyanide resistance in the catalase of the latter species.

scholarly journals Pangenome evolution in environmentally transmitted symbionts of deep-sea mussels is governed by vertical inheritance

2021 ◽  
Author(s):  
Devani Romero Picazo ◽  
Almut Werner ◽  
Tal Dagan ◽  
Anne Kupczok
Keyword(s):  
Gene Transfer ◽  
Horizontal Gene Transfer ◽  
Bacterial Genome ◽  
Cold Seep ◽  
Early Developmental Stage ◽  
Accessory Gene ◽  
Vertical Inheritance ◽  
Accessory Genes ◽  
Colonization Dynamics ◽  
Multiple Strains

Microbial pangenomes vary across species; their size and structure are determined by genetic diversity within the population and by gene loss and horizontal gene transfer (HGT). Many bacteria are associated with eukaryotic hosts where the host colonization dynamics may impact bacterial genome evolution. Host-associated lifestyle has been recognized as a barrier to HGT in parentally transmitted bacteria. However, pangenome evolution of environmentally acquired symbionts remains understudied, often due to limitations in symbiont cultivation. Using high-resolution metagenomics, here we study pangenome evolution of two co-occurring endosymbiont populations inhabiting individual Bathymodiolus brooksi mussels from a single cold seep. The symbionts, sulfur-oxidizing (SOX) and methane-oxidizing (MOX) gamma-proteobacteria, are environmentally acquired at an early developmental stage and individual mussels may harbor multiple strains of each species. We found differences in the accessory gene content of both symbionts across individual mussels, which are reflected by differences in symbiont strain composition. Compared to core genes, accessory genes are enriched in functions involved in genome integrity maintenance. We found no evidence for recent horizontal gene transfer between both symbionts. A comparison between the symbiont pangenomes revealed that the MOX population is less diverged and contains fewer accessory genes, supporting the view that the MOX association with B. brooksi is more recent than that of SOX. Our results show that the pangenomes of both symbionts evolved mainly by vertical inheritance. We conclude that association with individual hosts over their lifetime leads to genetically isolated symbiont subpopulations, constraining the frequency of HGT in the evolution of environmentally transmitted symbionts.

scholarly journals Genetic characterization of AmpC and extended-spectrum beta-lactamase (ESBL) phenotypes in Escherichia coli and Salmonella from Alberta poultry

2020 ◽  
Author(s):  
Tam Tran ◽  
Sylvia Checkley ◽  
Niamh Caffrey ◽  
Rashed Cassis ◽  
Chunu Mainali ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Gene Transfer ◽  
Horizontal Gene Transfer ◽  
Beta Lactamase ◽  
Drug Resistant ◽  
Gene Encoding ◽  
Extended Spectrum Beta Lactamase ◽  
E Coli ◽  
Extended Spectrum ◽  
Class 1

AbstractHorizontal gene transfer is an important mechanism which facilitates bacterial populations in overcoming antimicrobial treatment. In this study, a total of 120 Escherichia coli and 62 Salmonella enterica subsp. enterica isolates were isolated from poultry farms in Alberta. Fourteen serovars were identified among Salmonella isolates. Thirty one percent of E. coli isolates were multiclass drug resistant (resistant to ≥ 3 drug classes), while only about 16% of Salmonella isolates were multiclass drug resistant. Among those, eight E. coli isolates had an AmpC-type phenotype, and one Salmonella isolate had an extended-spectrum beta-lactamase (ESBL)-type β-lactamase phenotype. We identified both AmpC-type (blaCMY-2) and ESBL-type (blaTEM) genes in both E. coli and Salmonella isolates. Plasmids from eight of nine E. coli and Salmonella isolates were transferred to recipient strain E. coli J53 through conjugation. Transferable plasmids in above total eight E. coli and Salmonella isolates were also transferred into a lab-made sodium azide-resistant Salmonella recipient through conjugation. The class 1 integrase gene, int1, was detected on plasmids from two E. coli isolates. Further investigation of class 1 integron cassette regions revealed the presence of an aadA gene encoding streptomycin 3”-adenylyltransferase, an aadA1a/aadA2 gene encoding aminoglycoside 3”-O-adenyltransferase, and a putative adenylyltransferase gene. This study provides some insight into potential horizontal gene transfer events of antimicrobial resistance genes between E. coli and Salmonella in poultry production.

scholarly journals Contribution of Horizontal Gene Transfer to the Evolution of Saccharomyces cerevisiae

2005 ◽  
Vol 4 (6) ◽  
pp. 1102-1115 ◽  
Author(s):  
Charles Hall ◽  
Sophie Brachat ◽  
Fred S. Dietrich
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Gene Transfer ◽  
Horizontal Gene Transfer ◽  
Fungal Species ◽  
Dihydroorotate Dehydrogenase ◽  
Gene Encoding ◽  
Saccharomyces Bayanus ◽  
Potential Case ◽  
Bacterial Sources ◽  
Alpha Proteobacteria

ABSTRACT The genomes of the hemiascomycetes Saccharomyces cerevisiae and Ashbya gossypii have been completely sequenced, allowing a comparative analysis of these two genomes, which reveals that a small number of genes appear to have entered these genomes as a result of horizontal gene transfer from bacterial sources. One potential case of horizontal gene transfer in A. gossypii and 10 potential cases in S. cerevisiae were identified, of which two were investigated further. One gene, encoding the enzyme dihydroorotate dehydrogenase (DHOD), is potentially a case of horizontal gene transfer, as shown by sequencing of this gene from additional bacterial and fungal species to generate sufficient data to construct a well-supported phylogeny. The DHOD-encoding gene found in S. cerevisiae, URA1 (YKL216W), appears to have entered the Saccharomycetaceae after the divergence of the S. cerevisiae lineage from the Candida albicans lineage and possibly since the divergence from the A. gossypii lineage. This gene appears to have come from the Lactobacillales, and following its acquisition the endogenous eukaryotic DHOD gene was lost. It was also shown that the bacterially derived horizontally transferred DHOD is required for anaerobic synthesis of uracil in S. cerevisiae. The other gene discussed in detail is BDS1, an aryl- and alkyl-sulfatase gene of bacterial origin that we have shown allows utilization of sulfate from several organic sources. Among the eukaryotes, this gene is found in S. cerevisiae and Saccharomyces bayanus and appears to derive from the alpha-proteobacteria.

Sign in / Sign up

Export Citation Format

Share Document