scholarly journals Precise Characterization of Bombyx mori Fibroin Heavy Chain Gene Using Cpf1-Based Enrichment and Oxford Nanopore Technologies

Insects ◽  
2021 ◽  
Vol 12 (9) ◽  
pp. 832
Author(s):  
Wei Lu ◽  
Xinhui Lan ◽  
Tong Zhang ◽  
Hao Sun ◽  
Sanyuan Ma ◽  
...  
Keyword(s):  
Repeat Unit ◽  
Repetitive Sequences ◽  
Chain Gene ◽  
Enrichment Method ◽  
Repeat Units ◽  
Oxford Nanopore ◽  
Polymerase Chain ◽  
The Difference ◽  
Oxford Nanopore Technologies

To study the evolution of gene function and a species, it is essential to characterize the tandem repetitive sequences distributed across the genome. Cas9-based enrichment combined with nanopore sequencing is an important technique for targeting repetitive sequences. Cpf1 has low molecular weight, low off-target efficiency, and the same editing efficiency as Cas9. There are numerous studies on enrichment sequencing using Cas9 combined with nanopore, while there are only a few studies on the enrichment sequencing of long and highly repetitive genes using Cpf1. We developed Cpf1-based enrichment combined with ONT sequencing (CEO) to characterize the B. mori FibH gene, which is composed of many repeat units with a long and GC-rich sequence up to 17 kb and is not easily amplified by means of a polymerase chain reaction (PCR). CEO has four steps: the dephosphorylation of genomic DNA, the Cpf1 targeted cleavage of FibH, adapter ligation, and ONT sequencing. Using CEO, we determined the fine structure of B. moriFibH, which is 16,845 bp long and includes 12 repetitive domains separated by amorphous regions. Except for the difference of three bases in the intron from the reference gene, the other sequences are identical. Surprisingly, many methylated CG sites were found and distributed unevenly on the FibH repeat unit. The CEO we established is an available means to depict highly repetitive genes, but also a supplement to the enrichment method based on Cas9.

Dual Isoform Sequencing Reveals a Multifaceted Transcriptional Architecture of a Prototype Baculovirus

2021 ◽  
Author(s):  
Gábor Torma ◽  
Dóra Tombácz ◽  
Norbert Moldován ◽  
Ádám Fülöp ◽  
István Prazsák ◽  
...  
Keyword(s):  
Protein Coding ◽  
Rna Molecules ◽  
Non Coding Rna ◽  
Oxford Nanopore ◽  
The Pacific ◽  
Viral Genes ◽  
Long Read ◽  
Oxford Nanopore Technologies ◽  
Overlapping Transcripts

Abstract In this study, we used two long-read sequencing (LRS) techniques, Sequel from the Pacific Biosciences and MinION from Oxford Nanopore Technologies, for the transcriptional characterization of a prototype baculovirus, Autographacalifornica multiple nucleopolyhedrovirus. LRS is able to read full-length RNA molecules, and thereby to distinguish between transcript isoforms, mono- and polycistronic RNAs, and overlapping transcripts. Altogether, we detected 875 transcripts, of which 759 are novel and 116 have been annotated previously. These RNA molecules include 41 novel putative protein coding transcript (each containing 5’-truncated in-frame ORFs), 14 monocistronic transcripts, 99 multicistronic RNAs, 101 non-coding RNA, and 504 length isoforms. We also detected RNA methylation in 12 viral genes and RNA hyper-editing in the longer 5’-UTR transcript isoform of ORF 19 gene.

scholarly journals Microbial diversity characterization of seawater in a pilot study using Oxford Nanopore Technologies long-read sequencing

2020 ◽  
Author(s):  
Michael Liem ◽  
Tonny Regensburg-Tuïnk ◽  
Christiaan Henkel ◽  
Hans Jansen ◽  
Herman Spaink
Keyword(s):  
Microbial Diversity ◽  
Environmental Samples ◽  
Sea Water ◽  
Flow Cells ◽  
Oxford Nanopore ◽  
Challenging Tasks ◽  
Long Read ◽  
Close Relatives ◽  
Oxford Nanopore Technologies

Abstract Objective: Currently the majority of non-culturable microbes in sea water are yet to be discovered, Nanopore offers a solution to overcome the challenging tasks to identify the genomes and complex composition of oceanic microbiomes. In this study we evaluate the utility of Oxford Nanopore Technologies (ONT) sequencing to characterize microbial diversity in seawater from multiple locations. We compared the microbial species diversity of retrieved environmental samples from two different locations and time points.Results: With only three ONT flow cells we were able to identify thousands of organisms, including bacteriophages, from which a large part at species level. It was possible to assemble genomes from environmental samples with Flye. In several cases this resulted in >1 Mbp contigs and in the particular case of a Thioglobus singularis species it even produced a near complete genome. k-mer analysis reveals that a large part of the data represents species of which close relatives have not yet been deposited to the database. These results show that our approach is suitable for scalable genomic investigations such as monitoring oceanic biodiversity and provides a new platform for education in biodiversity.

scholarly journals Synthesis and Preliminary Characterization of a PPE-Type Polymer Containing Substituted Fullerenes and Transition Metal Ligation Sites

2015 ◽  
Vol 2015 ◽  
pp. 1-11
Author(s):  
Corinne A. Basinger ◽  
Kaitlin Sullivan ◽  
Sarah Siemer ◽  
Stuart Oehrle ◽  
Keith A. Walters
Keyword(s):  
Transition Metal ◽  
Excited States ◽  
Conjugated Polymer ◽  
Repeat Unit ◽  
Sonogashira Coupling ◽  
Polymeric Systems ◽  
Preliminary Characterization ◽  
Repeat Units ◽  
Future Work

A substituted fullerene was incorporated into a PPE-conjugated polymer repeat unit. This subunit was then polymerized via Sonogashira coupling with other repeat units to create polymeric systems approaching 50 repeat units (based on GPC characterization). Bipyridine ligands were incorporated into some of these repeat units to provide sites for transition metal coordination. Photophysical characterization of the absorption and emission properties of these systems shows excited states located on both the fullerene and aromatic backbone of the polymers that exist in a thermally controlled equilibrium. Future work will explore other substituted polyaromatic systems using similar methodologies.

scholarly journals Plasmidome analysis of carbapenem-resistant Enterobacteriaceae isolated in Vietnam

2020 ◽  
Author(s):  
Aki Hirabayashi ◽  
Koji Yahara ◽  
Satomi Mitsuhashi ◽  
So Nakagawa ◽  
Tadashi Imanishi ◽  
...  
Keyword(s):  
Carbapenem Resistance ◽  
Genomic Epidemiology ◽  
Carbapenem Resistant ◽  
Oxford Nanopore ◽  
Carbapenemase Gene ◽  
Long Read ◽  
Severe Infections ◽  
Oxford Nanopore Technologies ◽  
Carbapenem Resistant Enterobacteriaceae

Carbapenem-resistant Enterobacteriaceae (CRE) represent a serious threat to public health due to limited management of severe infections and high mortality. The rate of resistance of Enterobacteriaceae isolates to major antimicrobials, including carbapenems, is much higher in Vietnam than in Western countries, but the reasons remain unknown due to the lack of genomic epidemiology research. A previous study suggested that carbapenem resistance genes, such as the carbapenemase gene bla NDM-1 , spread via plasmids among Enterobacteriaceae in Vietnam. In this study, we performed detection and molecular characterization of bla NDM-1 -carrying plasmids in CRE isolated in Vietnam, and identified several possible cases of horizontal transfer of plasmids both within and among species of bacteria. Twenty-five carbapenem-resistant isolates from Enterobacteriaceae clinically isolated in a reference medical institution in Hanoi were sequenced on Illumina short-read sequencers, and 12 isolates harboring bla NDM-1 were sequenced on an Oxford Nanopore Technologies long-read sequencer to obtain complete plasmid sequences. Most of the plasmids co-carried genes conferring resistance to clinically relevant antimicrobials, including third-generation cephalosporins, aminoglycosides, and fluoroquinolones, in addition to bla NDM-1 , leading to multidrug resistance of their bacterial hosts. These results provide insight into the genetic basis of CRE in Vietnam, and could help control nosocomial infections.

scholarly journals Microbial diversity characterization of seawater in a pilot study using Oxford Nanopore Technologies long-read sequencing

2020 ◽  
Author(s):  
Michael Liem ◽  
A.J.G. Regensburg-Tuïnk ◽  
C.V. Henkel ◽  
H.P. Spaink
Keyword(s):  
Microbial Diversity ◽  
Environmental Samples ◽  
Sea Water ◽  
Flow Cells ◽  
Oxford Nanopore ◽  
Challenging Tasks ◽  
Long Read ◽  
Close Relatives ◽  
Oxford Nanopore Technologies

Abstract Objective Currently the majority of non-culturable microbes in sea water are yet to be discovered, Nanopore offers a solution to overcome the challenging tasks to identify the genomes and complex composition of oceanic microbiomes. In this study we evaluate the utility of Oxford Nanopore Technologies (ONT) sequencing to characterize microbial diversity in seawater from multiple locations. We compared the microbial species diversity of retrieved environmental samples from two different locations and time points. Results With only three ONT flow cells we were able to identify thousands of organisms, including bacteriophages, from which a large part at species level. It was possible to assemble genomes from environmental samples with Flye. In several cases this resulted in >1 Mbp contigs and in the particular case of a Thioglobus singularis species it even produced a near complete genome. k-mer analysis reveals that a large part of the data represents species of which close relatives have not yet been deposited to the database. These results show that our approach is suitable for scalable genomic investigations such as monitoring oceanic biodiversity and provides a new platform for education in biodiversity.

scholarly journals Microbial diversity characterization of seawater in a pilot study using Oxford Nanopore Technologies long-read sequencing

2021 ◽  
Vol 14 (1) ◽  
Author(s):  
M. Liem ◽  
T. Regensburg-Tuïnk ◽  
C. Henkel ◽  
H. Jansen ◽  
H. Spaink
Keyword(s):  
Microbial Diversity ◽  
Environmental Samples ◽  
Sea Water ◽  
Flow Cells ◽  
Oxford Nanopore ◽  
Challenging Tasks ◽  
Long Read ◽  
Close Relatives ◽  
Oxford Nanopore Technologies

Abstract Objective Currently the majority of non-culturable microbes in sea water are yet to be discovered, Nanopore offers a solution to overcome the challenging tasks to identify the genomes and complex composition of oceanic microbiomes. In this study we evaluate the utility of Oxford Nanopore Technologies (ONT) sequencing to characterize microbial diversity in seawater from multiple locations. We compared the microbial species diversity of retrieved environmental samples from two different locations and time points. Results With only three ONT flow cells we were able to identify thousands of organisms, including bacteriophages, from which a large part at species level. It was possible to assemble genomes from environmental samples with Flye. In several cases this resulted in > 1 Mbp contigs and in the particular case of a Thioglobus singularis species it even produced a near complete genome. k-mer analysis reveals that a large part of the data represents species of which close relatives have not yet been deposited to the database. These results show that our approach is suitable for scalable genomic investigations such as monitoring oceanic biodiversity and provides a new platform for education in biodiversity.

scholarly journals Microbial diversity characterization of seawater in a pilot study using Oxford Nanopore Technologies long-read sequencing

2020 ◽  
Author(s):  
M. Liem ◽  
A.J.G. Regensburg-Tuïnk ◽  
C.V. Henkel ◽  
H.P. Spaink
Keyword(s):  
Microbial Diversity ◽  
Environmental Samples ◽  
Sea Water ◽  
Flow Cells ◽  
Oxford Nanopore ◽  
Challenging Tasks ◽  
Long Read ◽  
Close Relatives ◽  
Oxford Nanopore Technologies

ABSTRACTCurrently the majority of non-culturable microbes in sea water are yet to be discovered, Nanopore offers a solution to overcome the challenging tasks to identify the genomes and complex composition of oceanic microbiomes. In this study we evaluate the utility of Oxford Nanopore Technologies (ONT) sequencing to characterize microbial diversity in seawater from multiple locations. We compared the microbial species diversity of retrieved environmental samples from two different locations and time points. With only three ONT flow cells we were able to identify thousands of organisms, including bacteriophages, from which a large part at species level. It was possible to assemble genomes from environmental samples with Flye. In several cases this resulted in >1 Mbp contigs and in the particular case of a Thioglobus singularis species it even produced a near complete genome. k-mer analysis reveals that a large part of the data represents species of which close relatives have not yet been deposited to the database. These results show that our approach is suitable for scalable genomic investigations such as monitoring oceanic biodiversity and provides a new platform for education in biodiversity

scholarly journals A comprehensive examination of Nanopore native RNA sequencing for characterization of complex transcriptomes

2019 ◽  
Author(s):  
Charlotte Soneson ◽  
Yao Yao ◽  
Anna Bratus-Neuenschwander ◽  
Andrea Patrignani ◽  
Mark D. Robinson ◽  
...  
Keyword(s):  
Rna Sequencing ◽  
Direct Sequencing ◽  
Transcript Level ◽  
Human Cell Lines ◽  
Oxford Nanopore ◽  
Comprehensive Examination ◽  
Important Addition ◽  
Overall Performance ◽  
Oxford Nanopore Technologies

AbstractA platform for highly parallel direct sequencing of native RNA strands was recently described by Oxford Nanopore Technologies (ONT); in order to assess overall performance in transcript-level investigations, the technology was applied for sequencing sets of synthetic transcripts as well as a yeast transcriptome. However, despite initial efforts it remains crucial to further investigate characteristics of ONT native RNA sequencing when applied to much more complex transcriptomes. Here we thus undertook extensive native RNA sequencing of polyA+ RNA from two human cell lines, and thereby analysed ~5.2 million aligned native RNA reads which consisted of a total of ~4.6 billion bases. To enable informative comparisons, we also performed relevant ONT direct cDNA- and Illumina-sequencing. We find that while native RNA sequencing does enable some of the anticipated advantages, key unexpected aspects hamper its performance, most notably the quite frequent inability to obtain full-length transcripts from single reads, as well as difficulties to unambiguously infer their true transcript of origin. While characterising issues that need to be addressed when investigating more complex transcriptomes, our study highlights that with some defined improvements, native RNA sequencing could be an important addition to the mammalian transcriptomics toolbox.

scholarly journals The evolutionary history of topological variations in the CPA/AT superfamily

2020 ◽  
Author(s):  
Sudha Govindarajan ◽  
Claudio Bassot ◽  
John Lamb ◽  
Nanjiang Shu ◽  
Yan Huang ◽  
...  
Keyword(s):  
Evolutionary History ◽  
Repeat Unit ◽  
Evolutionary Relationship ◽  
Structure Topology ◽  
Repeat Units ◽  
Novel Structure ◽  
Other Information ◽  
History Of ◽  
The Difference ◽  
And Function

CPA/AT transporters consist of two structurally and evolutionarily related inverted repeat units, each of them with one core and one scaffold subdomain. During evolution, these families have undergone substantial changes in structure, topology and function. Central to the function of the transporters is the existence of two non-canonical helices that are involved in the transport process. In different families, two different types of these helices have been identified, reentrant and broken. Here, we use an integrated topology annotation method to identify novel topologies in the families. It combines topology prediction, similarity to families with known structure, and the difference in positively charged residues present in inside and outside loops in alternative topological models. We identified families with diverse topologies containing broken or reentrant helix. We classified all families based on 3 distinct evolutionary groups that each share a structurally similar C-terminal repeat unit newly termed as Fold-types. Using the evolutionary relationship between families we propose topological transitions including, a transition between broken and reentrant helices, complete change of orientation, changes in the number of scaffold helices and even in some rare cases, losses of core helices. The evolutionary history of the repeat units shows gene duplication and repeat shuffling events to result in these extensive topology variations. The novel structure-based classification, together with supporting structural models and other information, is presented in a searchable database, CPAfold (cpafold.bioinfo.se). Our comprehensive study of topology variations within the CPA superfamily provides better insight about their structure and evolution.

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