scholarly journals Sequential induction of three recombination directionality factors directs assembly of tripartite integrative and conjugative elements

PLoS Genetics ◽  
2018 ◽  
Vol 14 (3) ◽  
pp. e1007292 ◽  
Author(s):  
Timothy L. Haskett ◽  
Jason J. Terpolilli ◽  
Vinoy K. Ramachandran ◽  
Callum J. Verdonk ◽  
Phillip S. Poole ◽  
...  
Keyword(s):  
Integrative And Conjugative Elements ◽  
Sequential Induction

Anterior Cervical Discectomy With Fusion and Plating for Correction of Degenerative Cervical Kyphosis: 2-Dimensional Operative Video

2020 ◽  
Author(s):  
Jeremy M V Guinn ◽  
Brenton Pennicooke ◽  
Joshua Rivera ◽  
Praveen V Mummaneni ◽  
Dean Chou
Keyword(s):  
Spinal Cord ◽  
Informed Consent ◽  
Bone Density ◽  
Surgical Intervention ◽  
Anterior Cervical Discectomy ◽  
Cervical Kyphosis ◽  
Nerve Roots ◽  
Cervical Discectomy ◽  
Cervical Plate ◽  
Sequential Induction

Abstract This surgical video demonstrates the technique for correcting degenerative cervical kyphosis using an anterior cervical discectomy and fusion (ACDF). Degenerative cervical kyphosis can cause radiculopathy, myelopathy, and difficulty holding up one's head. The goal of surgical intervention is to alleviate pain, improve the ability for upright gaze, and decompress the spinal cord or nerve roots. Posterior-only approaches and anterior corpectomies are alternative treatments to address cervical kyphosis. However, an ACDF allows for sequential induction of lordosis via distraction over multiple segments and for further lordosis induction by sequential screw tightening, pulling the spine towards a lordotic cervical plate.1 This video shows 2 cases demonstrating a technique of correcting severe cervical degenerative kyphosis. The video illustrates our initial kyphotic Caspar pin placement coupled with sequential anterior distraction to correct kyphosis. The technique is most useful in patients who have good bone density, nonankylosed facets, and degenerative cervical kyphosis. We have received informed consent of this patient to submit this video.

PHENOLS AS INTERMEDIATES IN THE DECOMPOSITION OF PHENOXYACETATES BY AN ARTHROBACTER SPECIES

1967 ◽  
Vol 13 (6) ◽  
pp. 679-690 ◽  
Author(s):  
M. A. Loos ◽  
R. N. Roberts ◽  
M. Alexander
Keyword(s):  
New Technique ◽  
Resting Cells ◽  
Substituted Phenols ◽  
Metabolic Sequence ◽  
A New Technique ◽  
Arthrobacter Species ◽  
High Yields ◽  
Sequential Induction

Decomposition of 2,4-dichlorophenoxyacetate (2,4-D) by a soil arthrobacter was studied using the technique of sequential induction. Compounds oxidized rapidly and without a lag by 2,4-D-grown cells, but slowly or not at all by citrate-grown cells, included 2,4-D, 2- and 4-chlorophenoxyacetate, 3,5-dichloro- and 4-chloro-catechol, catechol, 2,4-dichlorophenol, and 2- and 4-chlorophenol. The manometric data suggested that phenols and catechols were intermediates in the degradation of phenoxyacetates. Resting cells failed to accumulate chlorine-substituted phenols during the metabolism of halogenated phenoxyacetates, apparently because the phenols were oxidized as readily as they were formed. However, 2,4-D-induced cells contained enzymes which acted upon phenoxyacetate and 4-hydroxyphenoxyacetate, but these cells did not metabolize phenol and hydroquinone. Suspensions of such bacteria, but not citrate-grown cells, converted phenoxyacetate and 4-hydroxyphenoxyacetate almost completely to phenol and hydroquinone, respectively. The results indicate that the Arthrobacter sp. degrades 2,4-D via 2,4-dichlorophenol, and 2- and 4-chlorophenoxyacetate via 2- and 4-chlorophenol, respectively. The results also demonstrate a new technique for obtaining high yields of an intermediate in a metabolic sequence.

scholarly journals Evolutionary persistence of tripartite integrative and conjugative elements

Plasmid ◽  
2017 ◽  
Vol 92 ◽  
pp. 30-36 ◽  
Author(s):  
Timothy L. Haskett ◽  
Joshua P. Ramsay ◽  
Amanuel A. Bekuma ◽  
John T. Sullivan ◽  
Graham W. O'Hara ◽  
...  
Keyword(s):  
Integrative And Conjugative Elements ◽  
Evolutionary Persistence

scholarly journals EpicPCR 2.0: Technical and Methodological Improvement of a Cutting-Edge Single-Cell Genomic Approach

2021 ◽  
Vol 9 (8) ◽  
pp. 1649
Author(s):  
Véronica L. Roman ◽  
Christophe Merlin ◽  
Marko P. J. Virta ◽  
Xavier Bellanger
Keyword(s):  
Microbial Communities ◽  
Single Cell ◽  
Operational Taxonomic Unit ◽  
Rrna Gene ◽  
Environmental Matrices ◽  
Taxonomic Assignment ◽  
Integrative And Conjugative Elements ◽  
Functional Sequence ◽  
Methodological Improvement ◽  
New Gene

EpicPCR (Emulsion, Paired Isolation and Concatenation PCR) is a recent single-cell genomic method based on a fusion-PCR allowing us to link a functional sequence of interest to a 16S rRNA gene fragment and use the mass sequencing of the resulting amplicons for taxonomic assignment of the functional sequence-carrying bacteria. Although it is interesting because it presents the highest efficiency for assigning a bacterial host to a marker, epicPCR remains a complex multistage procedure with technical difficulties that may easily impair the approach depth and quality. Here, we described how to adapt epicPCR to new gene targets and environmental matrices while identifying the natural host range of SXT/R391 integrative and conjugative elements in water microbial communities from the Meurthe River (France). We notably show that adding a supplementary PCR step allowed us to increase the amplicon yield and thus the number of reads obtained after sequencing. A comparison of operational taxonomic unit (OTU) identification approaches when using biological and technical replicates demonstrated that, although OTUs can be validated when obtained from three out of three technical replicates, up to now, results obtained from two or three biological replicates give a similar and even a better confidence level in OTU identification, while allowing us to detect poorly represented SXT/R391 hosts in microbial communities.

Regionalization within the mammalian telencephalon is mediated by changes in responsiveness to Sonic Hedgehog

Development ◽  
1998 ◽  
Vol 125 (24) ◽  
pp. 5079-5089 ◽  
Author(s):  
J.D. Kohtz ◽  
D.P. Baker ◽  
G. Corte ◽  
G. Fishell
Keyword(s):  
Basal Ganglia ◽  
Globus Pallidus ◽  
Sonic Hedgehog ◽  
Adult Brain ◽  
Ganglionic Eminence ◽  
Lateral Ganglionic Eminence ◽  
Expression Characteristic ◽  
Sonic Hedgehog Gene ◽  
Embryonic Structure ◽  
Sequential Induction

The cortex and basal ganglia are the major structures of the adult brain derived from the embryonic telencephalon. Two morphologically distinct regions of the basal ganglia are evident within the mature ventral telencephalon, the globus pallidus medially, and the striatum, which is positioned between the globus pallidus and the cortex. Deletion of the Sonic Hedgehog gene in mice indicates that this secreted signaling molecule is vital for the generation of both these ventral telencephalic regions. Previous experiments showed that Sonic Hedgehog induces differentiation of ventral neurons characteristic of the medial ganglionic eminence, the embryonic structure which gives rise to the globus pallidus. In this paper, we show that later in development, Sonic Hedgehog induces ventral neurons with patterns of gene expression characteristic of the lateral ganglionic eminence. This is the embryonic structure from which the striatum is derived. These results suggest that temporally regulated changes in Sonic Hedgehog responsiveness are integral in the sequential induction of basal telencephalic structures.

scholarly journals Integrative and Conjugative Elements (ICE) and Associated Cargo Genes within and across Hundreds of Bacterial Genera

2020 ◽  
Author(s):  
James H Kaufman ◽  
Ignacio Terrizzano ◽  
Gowri Nayar ◽  
Ed Seabolt ◽  
Akshay Agarwal ◽  
...  
Keyword(s):  
Big Data ◽  
Data Analysis ◽  
Big Data Analysis ◽  
Gene Exchange ◽  
Bacterial Genomes ◽  
Phenotypic Properties ◽  
Evolutionary Mechanism ◽  
Data Resource ◽  
Integrative And Conjugative Elements ◽  
Susceptibility Assay

AbstractHorizontal gene transfer mediated by integrative and conjugative elements (ICE) is considered an important evolutionary mechanism of bacteria. It allows organisms to quickly evolve new phenotypic properties including antimicrobial resistance (AMR) and virulence. The rate of ICE-mediated cargo gene exchange has not yet been comprehensively studied within and between bacterial taxa. In this paper we report a big data analysis of ICE and associated cargo genes across over 200,000 bacterial genomes representing 1,345 genera. Our results reveal that half of bacterial genomes contain one or more known ICE features (“ICE genomes”), and that the associated genetic cargo may play an important role in the spread of AMR genes within and between bacterial genera. We identify 43 AMR genes that appear only in ICE genomes and never in non-ICE genomes. A further set of 95 AMR genes are found >5x more often in ICE versus non-ICE genomes. In contrast, only 29 AMR genes are observed more frequently (at least 5:1) in non-ICE genomes compared to ICE genomes. Analysis of NCBI antibiotic susceptibility assay data reveals that ICE genomes are also over-represented amongst phenotypically resistant isolates, suggesting that ICE processes are critical for both genotypic and phenotypic AMR. These results, as well as the underlying big data resource, are important foundational tools for understanding bacterial evolution, particularly in relation to important bacterial phenotypes such as AMR.

scholarly journals Autonomous Replication of the Conjugative Transposon Tn916

2016 ◽  
Vol 198 (24) ◽  
pp. 3355-3366 ◽  
Author(s):  
Laurel D. Wright ◽  
Alan D. Grossman
Keyword(s):  
Gene Transfer ◽  
Horizontal Gene Transfer ◽  
Origin Of Replication ◽  
Rolling Circle Replication ◽  
Conjugative Transposon ◽  
Rolling Circle ◽  
Autonomous Replication ◽  
Integrative And Conjugative Elements ◽  
Rolling Circle Mechanism ◽  
Origin Of Transfer

ABSTRACTIntegrative and conjugative elements (ICEs), also known as conjugative transposons, are self-transferable elements that are widely distributed among bacterial phyla and are important drivers of horizontal gene transfer. Many ICEs carry genes that confer antibiotic resistances to their host cells and are involved in the dissemination of these resistance genes. ICEs reside in host chromosomes but under certain conditions can excise to form a plasmid that is typically the substrate for transfer. A few ICEs are known to undergo autonomous replication following activation. However, it is not clear if autonomous replication is a general property of many ICEs. We found that Tn916, the first conjugative transposon identified, replicates autonomously via a rolling-circle mechanism. Replication of Tn916was dependent on the relaxase encoded byorf20of Tn916. The origin of transfer of Tn916,oriT(916), also functioned as an origin of replication. Using immunoprecipitation and mass spectrometry, we found that the relaxase (Orf20) and the two putative helicase processivity factors (Orf22 and Orf23) encoded by Tn916likely interact in a complex and that the Tn916relaxase contains a previously unidentified conserved helix-turn-helix domain in its N-terminal region that is required for relaxase function and replication. Lastly, we identified a functional single-strand origin of replication (sso) in Tn916that we predict primes second-strand synthesis during rolling-circle replication. Together these results add to the emerging data that show that several ICEs replicate via a conserved, rolling-circle mechanism.IMPORTANCEIntegrative and conjugative elements (ICEs) drive horizontal gene transfer and the spread of antibiotic resistances in bacteria. ICEs reside integrated in a host genome but can excise to create a plasmid that is the substrate for transfer to other cells. Here we show that Tn916, an ICE with broad host range, undergoes autonomous rolling-circle replication when in the plasmid form. We found that the origin of transfer functions as a double-stranded origin of replication and identified a single-stranded origin of replication. It was long thought that ICEs do not undergo autonomous replication. Our work adds to the evidence that ICEs replicate autonomously as part of their normal life cycle and indicates that diverse ICEs use the same replicative mechanism.

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