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July 7, 2019

Resolving complex structural genomic rearrangements using a randomized approach.

Complex chromosomal rearrangements are structural genomic alterations involving multiple instances of deletions, duplications, inversions, or translocations that co-occur either on the same chromosome or represent different overlapping events on homologous chromosomes. We present SVelter, an algorithm that identifies regions of the genome suspected to harbor a complex event and then resolves the structure by iteratively rearranging the local genome structure, in a randomized fashion, with each structure scored against characteristics of the observed sequencing data. SVelter is able to accurately reconstruct complex chromosomal rearrangements when compared to well-characterized genomes that have been deeply sequenced with both short and long reads.


July 7, 2019

Complete genome sequence of Klebsiella pneumoniae subsp. pneumoniae KP617, coproducing OXA-232 and NDM-1 carbapenemases, isolated in South Korea.

The prevalence of Klebsiella pneumoniae coproducing carbapenemase metallo-ß-lactamase 1 (NDM-1) and OXA-48 has been increasing globally since 2013. The complete genome of KP617 was sequenced and assembled into a circular chromosome and two plasmids. This sequence provides the genetic background for understanding the evolution of carbapenemase genes in K. pneumoniae KP617.


July 7, 2019

Genome of Cnaphalocrocis medinalis granulovirus, the first Crambidae-infecting betabaculovirus isolated from rice leaffolder to sequenced.

Cnaphalocrocis medinalis is a major pest of rice in South and South-East Asia. Insecticides are the major means farmers use for management. A naturally occurring baculovirus, C. medinalis granulovirus (CnmeGV), has been isolated from the larvae and this has the potential for use as microbial agent. Here, we described the complete genome sequence of CnmeGV and compared it to other baculovirus genomes. The genome of CnmeGV is 112,060 base pairs in length, has a G+C content of 35.2%. It contains 133 putative open reading frames (ORFs) of at least 150 nucleotides. A hundred and one (101) of these ORFs are homologous to other baculovirus genes including 37 baculovirus core genes. Thirty-two (32) ORFs are unique to CnmeGV with no homologues detected in the GeneBank and 53 tandem repeats (TRs) with sequence length from 25 to 551 nt intersperse throughout the genome of CnmeGV. Six (6) homologous regions (hrs) were identified interspersed throughout the genome. Hr2 contains 11 imperfect palindromes and a high content of AT sequence (about 73%). The unique ORF28 contains a coiled-coil region and a zinc finger-like domain of 4-50 residues specialized by two C2C2 zinc finger motifs that putatively bound two atoms of zinc. ORF21 encoding a chit-1 protein suggesting a horizontal gene transfer from alphabaculovirus. The putative protein presents two carbohydrate-binding module family 14 (CBM_14) domains rather than other homologues detected from betabaculovirus that only contains one chit-binding region. Gene synteny maps showed the colinearity of sequenced betabaculovirus. Phylogenetic analysis indicated that CnmeGV grouped in the betabaculovirus, with a close relation to AdorGV. The cladogram obtained in this work grouped the 17 complete GV genomes in one monophyletic clade. CnmeGV represents a new crambidae host-isolated virus species from the genus Betabaculovirus and is most closely relative of AdorGV. The analyses and information derived from this study will provide a better understanding of the pathological symptoms caused by this virus and its potential use as a microbial pesticide.


July 7, 2019

Complete genome sequences of two interactive moderate thermophiles, Paenibacillus napthalenovorans 32O-Y and Paenibacillus sp. 32O-W.

Microorganisms with the capability to desulfurize petroleum are in high demand with escalating restrictions currently placed on fuel purity. Thermophilic desulfurizers are particularly valuable in high-temperature industrial applications. We report the whole-genome sequences of Paenibacillus napthalenovorans 32O-Y and Paenibacillus sp. 32O-W, which can and cannot, respectively, metabolize dibenzothiophene. Copyright © 2016 Butler et al.


July 7, 2019

Complete genome sequences of the obligate symbionts “Candidatus Sulcia muelleri” and “Ca. Nasuia deltocephalinicola” from the pestiferous leafhopper Macrosteles quadripunctulatus (Hemiptera: Cicadellidae).

Two bacterial symbionts of the European pest leafhopper, Macrosteles quadripunctulatus (Hemiptera: Cicadellidae), were fully sequenced. “Candidatus Sulcia muelleri” and “Ca. Nasuia deltocephalinicola” represent two of the smallest known bacterial genomes at 190 kb and 112 kb, respectively. Genome sequences are nearly identical to strains reported from the closely related host species, M. quadrilineatus. Copyright © 2016 Bennett et al.


July 7, 2019

A time- and cost-effective strategy to sequence mammalian Y Chromosomes: an application to the de novo assembly of gorilla Y.

The mammalian Y Chromosome sequence, critical for studying male fertility and dispersal, is enriched in repeats and palindromes, and thus, is the most difficult component of the genome to assemble. Previously, expensive and labor-intensive BAC-based techniques were used to sequence the Y for a handful of mammalian species. Here, we present a much faster and more affordable strategy for sequencing and assembling mammalian Y Chromosomes of sufficient quality for most comparative genomics analyses and for conservation genetics applications. The strategy combines flow sorting, short- and long-read genome and transcriptome sequencing, and droplet digital PCR with novel and existing computational methods. It can be used to reconstruct sex chromosomes in a heterogametic sex of any species. We applied our strategy to produce a draft of the gorilla Y sequence. The resulting assembly allowed us to refine gene content, evaluate copy number of ampliconic gene families, locate species-specific palindromes, examine the repetitive element content, and produce sequence alignments with human and chimpanzee Y Chromosomes. Our results inform the evolution of the hominine (human, chimpanzee, and gorilla) Y Chromosomes. Surprisingly, we found the gorilla Y Chromosome to be similar to the human Y Chromosome, but not to the chimpanzee Y Chromosome. Moreover, we have utilized the assembled gorilla Y Chromosome sequence to design genetic markers for studying the male-specific dispersal of this endangered species. © 2016 Tomaszkiewicz et al.; Published by Cold Spring Harbor Laboratory Press.


July 7, 2019

Third-generation sequencing and the future of genomics

Third-generation long-range DNA sequencing and mapping technologies are creating a renaissance in high-quality genome sequencing. Unlike second-generation sequencing, which produces short reads a few hundred base-pairs long, third-generation single-molecule technologies generate over 10,000 bp reads or map over 100,000 bp molecules. We analyze how increased read lengths can be used to address long-standing problems in de novo genome assembly, structural variation analysis and haplotype phasing.


July 7, 2019

Complete genome sequence of the Sporosarcina psychrophila DSM 6497, a psychrophilic Bacillus strain that mediates the calcium carbonate precipitation.

Sporosarcina psychrophila DSM 6497 is a gram positive, spore-formation psychrophilic bacterial strain, widely distributed in terrestrial and aquatic environments. Here we report its complete sequence including one circular chromosome of 4674191bp with a GC content of 40.3%. Genes encoding urease are predicted in the genome, which provide insight information on the microbiologically mediated urea hydrolysis process. This urea hydrolysis can further lead to an increase of carbonate anion and alkalinity in the environment, which promotes the microbiologically induced carbonate precipitation with various applications, such as the bioremediation of calcium rich wastewater and bio-reservation of architectural patrimony. Copyright © 2016 Elsevier B.V. All rights reserved.


July 7, 2019

Complete genome sequence of Acinetobacter sp. TTH0-4, a cold-active crude oil degrading strain isolated from Qinghai-Tibet Plateau.

Acinetobacter sp. strain TTH0-4 was isolated from a permafrost region in Qinghai-Tibet Plateau. With its capability to degrade crude oil at low temperature, 10°C, the strain could be an excellent candidate for the bioremediation of crude oil pollution in cold areas or at cold seasons. We sequenced and annotated the whole genome to serve as a basis for further elucidation of the genetic background of this promising strain, and provide opportunities for investigating the metabolic and regulatory mechanisms and optimizing the biodegradative activity in cold environment. Copyright © 2016. Published by Elsevier B.V.


July 7, 2019

A pigeonpea gene confers resistance to Asian soybean rust in soybean.

Asian soybean rust (ASR), caused by the fungus Phakopsora pachyrhizi, is one of the most economically important crop diseases, but is only treatable with fungicides, which are becoming less effective owing to the emergence of fungicide resistance. There are no commercial soybean cultivars with durable resistance to P. pachyrhizi, and although soybean resistance loci have been mapped, no resistance genes have been cloned. We report the cloning of a P. pachyrhizi resistance gene CcRpp1 (Cajanus cajan Resistance against Phakopsora pachyrhizi 1) from pigeonpea (Cajanus cajan) and show that CcRpp1 confers full resistance to P. pachyrhizi in soybean. Our findings show that legume species related to soybean such as pigeonpea, cowpea, common bean and others could provide a valuable and diverse pool of resistance traits for crop improvement.


July 7, 2019

Analysis of the genome sequence of the medicinal plant Salvia miltiorrhiza.

Salvia miltiorrhiza Bunge (Danshen) is a medicinal plant of the Lamiaceae family, and its dried roots have long been used in traditional Chinese medicine with hydrophilic phenolic acids and tanshinones as pharmaceutically active components (Zhang et al., 2014; Xu et al., 2016). The first step of tanshinone biosynthesis is bicyclization of the general diterpene precursor (E,E,E)-geranylgeranyl diphosphate (GGPP) to copalyl diphosphate (CPP) by CPP synthases (CPSs), which is followed by a cyclization or rearrangement reaction catalyzed by kaurene synthase-like enzymes (KSL).


July 7, 2019

Genome sequence and analysis of a stress-tolerant, wild-derived strain of Saccharomyces cerevisiae used in biofuels research

The genome sequences of more than 100 strains of the yeast Saccharomyces cerevisiae have been published. Unfortunately, most of these genome assemblies contain dozens to hundreds of gaps at repetitive sequences, including transposable elements, tRNAs, and subtelomeric regions, which is where novel genes generally reside. Relatively few strains have been chosen for genome sequencing based on their biofuel production potential, leaving an additional knowledge gap. Here, we describe the nearly complete genome sequence of GLBRCY22-3 (Y22-3), a strain of S. cerevisiae derived from the stress-tolerant wild strain NRRL YB-210 and subsequently engineered for xylose metabolism. After benchmarking several genome assembly approaches, we developed a pipeline to integrate Pacific Biosciences (PacBio) and Illumina sequencing data and achieved one of the highest quality genome assemblies for any S. cerevisiae strain. Specifically, the contig N50 is 693 kbp, and the sequences of most chromosomes, the mitochondrial genome, and the 2-micron plasmid are complete. Our annotation predicts 92 genes that are not present in the reference genome of the laboratory strain S288c, over 70% of which were expressed. We predicted functions for 43 of these genes, 28 of which were previously uncharacterized and unnamed. Remarkably, many of these genes are predicted to be involved in stress tolerance and carbon metabolism and are shared with a Brazilian bioethanol production strain, even though the strains differ dramatically at most genetic loci. The Y22-3 genome sequence provides an exceptionally high-quality resource for basic and applied research in bioenergy and genetics. Copyright © 2016 McIlwain et al.


July 7, 2019

Complete mitochondrial genome sequence of the pezizomycete Pyronema confluens.

The complete mitochondrial genome of the ascomycete Pyronema confluens has been sequenced. The circular genome has a size of 191 kb and contains 48 protein-coding genes, 26 tRNA genes, and two rRNA genes. Of the protein-coding genes, 14 encode conserved mitochondrial proteins, and 31 encode predicted homing endonuclease genes. Copyright © 2016 Nowrousian.


July 7, 2019

The channel catfish genome sequence provides insights into the evolution of scale formation in teleosts.

Catfish represent 12% of teleost or 6.3% of all vertebrate species, and are of enormous economic value. Here we report a high-quality reference genome sequence of channel catfish (Ictalurus punctatus), the major aquaculture species in the US. The reference genome sequence was validated by genetic mapping of 54,000 SNPs, and annotated with 26,661 predicted protein-coding genes. Through comparative analysis of genomes and transcriptomes of scaled and scaleless fish and scale regeneration experiments, we address the genomic basis for the most striking physical characteristic of catfish, the evolutionary loss of scales and provide evidence that lack of secretory calcium-binding phosphoproteins accounts for the evolutionary loss of scales in catfish. The channel catfish reference genome sequence, along with two additional genome sequences and transcriptomes of scaled catfishes, provide crucial resources for evolutionary and biological studies. This work also demonstrates the power of comparative subtraction of candidate genes for traits of structural significance.


July 7, 2019

Atypical Salmonella enterica serovars in murine and human infection models: Is it time to reassess our approach to the study of salmonellosis?

Nontyphoidal Salmonella species are globally disseminated pathogens and the predominant cause of gastroenteritis. The pathogenesis of salmonellosis has been extensively studied using in vivo murine models and cell lines typically challenged with Salmonella Typhimurium. Although serovars Enteritidis and Typhimurium are responsible for the most of human infections reported to the CDC, several other serovars also contribute to clinical cases of salmonellosis. Despite their epidemiological importance, little is known about their infection phenotypes. Here, we report the virulence characteristics and genomes of 10 atypical S. enterica serovars linked to multistate foodborne outbreaks in the United States. We show that the murine RAW 264.7 macrophage model of infection is unsuitable for inferring human relevant differences in nontyphoidal Salmonella infections whereas differentiated human THP-1 macrophages allowed these isolates to be further characterised in a more relevant, human context.


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