To start Day 1 of the PacBio User Group Meeting, Jonas Korlach, PacBio CSO, provides an update on the latest releases and performance metrics for the Sequel II System. The…
In this PacBio User Group Meeting lightning talk, Shawn Polson of the University of Delaware speaks about viral metagenomes, which are more challenging to distinguish than their bacterial counterparts because…
Understanding interactions among plants and the complex communities of organisms living on, in and around them requires more than one experimental approach. A new method for de novo metagenome assembly,…
In this talk at PAG 2020, PacBio Plant and Animal Sciences Marketing Manager Michelle Vierra discusses recent updates to Single Molecule, Real-Time (SMRT) Sequencing technology, including the Sequel II System,…
In this webinar, Kristin Mars, Sequencing Specialist, PacBio, presents an introduction to PacBio’s technology and its applications followed by a panel discussion among sequencing experts. The panel discussion addresses such…
In this webinar, Dr. Ashby gives attendees a brief update on PacBio’s metagenomics solutions on the Sequel II System. Then, Dr. Ma, University of Maryland School of Medicine, discusses her…
The Earlham Institute was one of the first labs to adopt the PacBio Sequel II System. Karim Gharbi, Head of Genomics Pipelines, discusses how SMRT Sequencing and HiFi reads have…
Highly accurate long reads, known as HiFi reads, are a new tool in scientists’ sequencing toolbox. Hear PacBio users share how they are using HiFi reads to explore the genomes,…
The utility of new highly accurate long reads, or HiFi reads, was first demonstrated for calling all variant types in human genomes. It has since been shown that HiFi reads…
The widespread occurrence of repetitive stretches of DNA in genomes of organisms across the tree of life imposes fundamental challenges for sequencing, genome assembly, and automated annotation of genes and proteins. This multi-level problem can lead to errors in genome and protein databases that are often not recognized or acknowledged. As a consequence, end users working with sequences with repetitive regions are faced with ‘ready-to-use’ deposited data whose trustworthiness is difficult to determine, let alone to quantify. Here, we provide a review of the problems associated with tandem repeat sequences that originate from different stages during the sequencing-assembly-annotation-deposition workflow, and that may proliferate in public database repositories affecting all downstream analyses. As a case study, we provide examples of the Atlantic cod genome, whose sequencing and assembly were hindered by a particularly high prevalence of tandem repeats. We complement this case study with examples from other species, where mis-annotations and sequencing errors have propagated into protein databases. With this review, we aim to raise the awareness level within the community of database users, and alert scientists working in the underlying workflow of database creation that the data they omit or improperly assemble may well contain important biological information valuable to others. © The Author(s) 2019. Published by Oxford University Press on behalf of Nucleic Acids Research.
Forest tree species are increasingly subject to severe mortalities from exotic pests, diseases, and invasive organisms, accelerated by climate change. Forest health issues are threatening multiple species and ecosystem sustainability globally. While sources of resistance may be available in related species, or among surviving trees, introgression of resistance genes into threatened tree species in reasonable time frames requires genome-wide breeding tools. Asian species of chestnut (Castanea spp.) are being employed as donors of disease resistance genes to restore native chestnut species in North America and Europe. To aid in the restoration of threatened chestnut species, we present the assembly of a reference genome with chromosome-scale sequences for Chinese chestnut (C. mollissima), the disease-resistance donor for American chestnut restoration. We also demonstrate the value of the genome as a platform for research and species restoration, including new insights into the evolution of blight resistance in Asian chestnut species, the locations in the genome of ecologically important signatures of selection differentiating American chestnut from Chinese chestnut, the identification of candidate genes for disease resistance, and preliminary comparisons of genome organization with related species.
Long-read sequencing technologies substantially improved assemblies of many isolate bacterial genomes as compared to fragmented assemblies produced with short-read technologies. However, assembling complex metagenomic datasets remains a challenge even for the state-of-the-art long-read assemblers. To address this gap, we present the metaFlye assembler and demonstrate that it generates highly contiguous and accurate metagenome assemblies. In contrast to short-read metagenomics assemblers that typically fail to reconstruct full-length 16S RNA genes, metaFlye captures many 16S RNA genes within long contigs, thus providing new opportunities for analyzing the microbial “dark matter of life”. We also demonstrate that long-read metagenome assemblers significantly improve full-length plasmid and virus reconstruction as compared to short-read assemblers and reveal many novel plasmids and viruses.
For the first time, full-length 16S rRNA sequencing method was applied to disclose the bacterial species and communities of a full-scale wastewater treatment plant using an anaerobic/anoxic/oxic (A/A/O) process in Wuhan, China. The compositions of the bacteria at phylum and class levels in the activated sludge were similar to which revealed by Illumina Miseq sequencing. At genus and species levels, third-generation sequencing showed great merits and accuracy. Typical functional taxa classified to ammonia-oxidizing bacteria (AOB), nitrite-oxidizing bacteria (NOB), denitrifying bacteria (DB), anaerobic ammonium oxidation bacteria (ANAMMOXB) and polyphosphate-accumulating organisms (PAOs) were presented, which were Nitrosomonas (1.11%), Nitrospira (3.56%), Pseudomonas (3.88%), Planctomycetes (13.80%), Comamonadaceae (1.83%), respectively. Pseudomonas (3.88%) and Nitrospira (3.56%) were the most predominating two genera, mainly containing Pseudomonas extremaustralis (1.69%), Nitrospira defluvii (3.13%), respectively. Bacteria regarding to nitrogen and phosphorus removal at species level were put forward. The predicted functions proved that the A/A/O process was efficient regarding nitrogen and organics removal. Copyright © 2019 The Society for Biotechnology, Japan. Published by Elsevier B.V. All rights reserved.
A marine psychrophilic bacterium _Paenisporosarcina antarctica_ CGMCC 1.6503T (= JCM 14646T) was isolated off King George Island, Antarctica (62°13’31? S 58°57’08? W). In this study, we report the complete genome sequence of _Paenisporosarcina antarctica_, which is comprised of 3,972,524?bp with a mean G?+?C content of 37.0%. By gene function and metabolic pathway analyses, studies showed that strain CGMCC 1.6503T encodes a series of genes related to cold adaptation, including encoding fatty acid desaturases, dioxygenases, antifreeze proteins and cold shock proteins, and possesses several two-component regulatory systems, which could assist this strain in responding to the cold stress, the oxygen stress and the osmotic stress in Antarctica. The complete genome sequence of _P. antarctica_ may provide further insights into the genetic mechanism of cold adaptation for Antarctic marine bacteria.
Chemical defense against predators is widespread in natural ecosystems. Occasionally, taxonomically distant organisms share the same defense chemical. Here, we describe an unusual tripartite marine symbiosis, in which an intracellular bacterial symbiont (“Candidatus Endobryopsis kahalalidefaciens”) uses a diverse array of biosynthetic enzymes to convert simple substrates into a library of complex molecules (the kahalalides) for chemical defense of the host, the alga Bryopsis sp., against predation. The kahalalides are subsequently hijacked by a third partner, the herbivorous mollusk Elysia rufescens, and employed similarly for defense. “Ca E. kahalalidefaciens” has lost many essential traits for free living and acts as a factory for kahalalide production. This interaction between a bacterium, an alga, and an animal highlights the importance of chemical defense in the evolution of complex symbioses.Copyright © 2019 The Authors, some rights reserved; exclusive licensee American Association for the Advancement of Science. No claim to original U.S. Government Works.
If you have a question, need to check the status of an order, or are interested in purchasing an instrument, we're here to help.