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Asset Tag: Whole Genome Sequencing,

July 7, 2019

A high-coverage draft genome of the mycalesine butterfly Bicyclus anynana.

The mycalesine butterfly Bicyclus anynana , the ‘Squinting bush brown’, is a model organism in the study of lepidopteran ecology, development and evolution. Here, we present a draft genome sequence for B. anynana to serve as a genomics resource for current and future studies of this important model species.Seven libraries with insert sizes ranging from 350 bp to 20 kb were constructed using DNA from an inbred female and sequenced using both Illumina and PacBio technology. 128 Gb raw Illumina data were filtered to 124 Gb and assembled to a final size of 475 Mb (~260X assembly coverage). Contigs were scaffolded using mate-pair, transcriptome and PacBio data into 10,800 sequences with an N50 of 638 kb (longest scaffold 5 Mb). The genome is comprised of 26% repetitive elements, and encodes a total of 22,642 predicted protein-coding genes. Recovery of a BUSCO set of core metazoan genes was almost complete (98%). Overall, these metrics compare well with other recently published lepidopteran genomes.We report a high-quality draft genome sequence for Bicyclus anynana . The genome assembly and annotated gene models are available at LepBase ( http://ensembl.lepbase.org/index.html ).

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July 7, 2019

Genome graphs

There is increasing recognition that a single, monoploid reference genome is a poor universal reference structure for human genetics, because it represents only a tiny fraction of human variation. Adding this missing variation results in a structure that can be described as a mathematical graph: a genome graph. We demonstrate that, in comparison to the existing reference genome (GRCh38), genome graphs can substantially improve the fractions of reads that map uniquely and perfectly. Furthermore, we show that this fundamental simplification of read mapping transforms the variant calling problem from one in which many non-reference variants must be discovered de-novo to one in which the vast majority of variants are simply re-identified within the graph. Using standard benchmarks as well as a novel reference-free evaluation, we show that a simplistic variant calling procedure on a genome graph can already call variants at least as well as, and in many cases better than, a state-of-the-art method on the linear human reference genome. We anticipate that graph-based references will supplant linear references in humans and in other applications where cohorts of sequenced individuals are available.

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July 7, 2019

Evolutionary dynamics of pathoadaptation revealed by three independent acquisitions of the VirB/D4 type IV secretion system in Bartonella.

The a-proteobacterial genus Bartonella comprises a group of ubiquitous mammalian pathogens that are studied as a model for the evolution of bacterial pathogenesis. Vast abundance of two particular phylogenetic lineages of Bartonella had been linked to enhanced host adaptability enabled by lineage-specific acquisition of a VirB/D4 type IV secretion system (T4SS) and parallel evolution of complex effector repertoires. However, the limited availability of genome sequences from one of those lineages as well as other, remote branches of Bartonella has so far hampered comprehensive understanding of how the VirB/D4 T4SS and its effectors called Beps have shaped Bartonella evolution. Here, we report the discovery of a third repertoire of Beps associated with the VirB/D4 T4SS of B. ancashensis, a novel human pathogen that lacks any signs of host adaptability and is only distantly related to the two species-rich lineages encoding a VirB/D4 T4SS. Furthermore, sequencing of ten new Bartonella isolates from under-sampled lineages enabled combined in silico analyses and wet lab experiments that suggest several parallel layers of functional diversification during evolution of the three Bep repertoires from a single ancestral effector. Our analyses show that the Beps of B. ancashensis share many features with the two other repertoires, but may represent a more ancestral state that has not yet unleashed the adaptive potential of such an effector set. We anticipate that the effectors of B. ancashensis will enable future studies to dissect the evolutionary history of Bartonella effectors and help unraveling the evolutionary forces underlying bacterial host adaptation.© The Author(s) 2017. Published by Oxford University Press on behalf of the Society for Molecular Biology and Evolution.

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July 7, 2019

Free-living Enterobacterium Pragia fontium 24613: complete genome sequence and metabolic profiling.

Pragia fontium is one of the few species that belongs to the group of atypical hydrogen sulfide-producing enterobacteria. Unlike other members of this closely related group, P. fontium is not associated with any known host and has been reported as a free-living bacterium. Whole genome sequencing and metabolic fingerprinting confirmed the phylogenetic position of P. fontium inside the group of atypical H2S producers. Genomic data have revealed that P. fontium 24613 has limited pathogenic potential, although there are signs of genome decay. Although the lack of specific virulence factors and no association with a host species suggest a free-living style, the signs of genome decay suggest a process of adaptation to an as-yet-unknown host.

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July 7, 2019

Improved high-quality draft genome sequence and annotation of Burkholderia contaminans LMG 23361T.

Burkholderia contaminans LMG 23361 is the type strain of the species isolated from the milk of a dairy sheep with mastitis. Some pharmaceutical products contain disinfectants such as benzalkonium chloride (BZK) and previously we reported that B. contaminans LMG 23361(T) possesses the ability to inactivate BZK with high biodegradation rates. Here, we report an improved high-quality draft genome sequence of this strain. Copyright © 2017 Jung et al.

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July 7, 2019

Proteogenomics produces comprehensive and highly accurate protein-coding gene annotation in a complete genome assembly of Malassezia sympodialis.

Complete and accurate genome assembly and annotation is a crucial foundation for comparative and functional genomics. Despite this, few complete eukaryotic genomes are available, and genome annotation remains a major challenge. Here, we present a complete genome assembly of the skin commensal yeast Malassezia sympodialis and demonstrate how proteogenomics can substantially improve gene annotation. Through long-read DNA sequencing, we obtained a gap-free genome assembly for M. sympodialis (ATCC 42132), comprising eight nuclear and one mitochondrial chromosome. We also sequenced and assembled four M. sympodialis clinical isolates, and showed their value for understanding Malassezia reproduction by confirming four alternative allele combinations at the two mating-type loci. Importantly, we demonstrated how proteomics data could be readily integrated with transcriptomics data in standard annotation tools. This increased the number of annotated protein-coding genes by 14% (from 3612 to 4113), compared to using transcriptomics evidence alone. Manual curation further increased the number of protein-coding genes by 9% (to 4493). All of these genes have RNA-seq evidence and 87% were confirmed by proteomics. The M. sympodialis genome assembly and annotation presented here is at a quality yet achieved only for a few eukaryotic organisms, and constitutes an important reference for future host-microbe interaction studies.© The Author(s) 2017. Published by Oxford University Press on behalf of Nucleic Acids Research.

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July 7, 2019

Whole genome sequencing and analysis of Campylobacter coli YH502 from retail chicken reveals a plasmid-borne type VI secretion system.

Campylobacter is a major cause of foodborne illnesses worldwide. Campylobacter infections, commonly caused by ingestion of undercooked poultry and meat products, can lead to gastroenteritis and chronic reactive arthritis in humans. Whole genome sequencing (WGS) is a powerful technology that provides comprehensive genetic information about bacteria and is increasingly being applied to study foodborne pathogens: e.g., evolution, epidemiology/outbreak investigation, and detection. Herein we report the complete genome sequence of Campylobacter coli strain YH502 isolated from retail chicken in the United States. WGS, de novo assembly, and annotation of the genome revealed a chromosome of 1,718,974 bp and a mega-plasmid (pCOS502) of 125,964 bp. GC content of the genome was 31.2% with 1931 coding sequences and 53 non-coding RNAs. Multiple virulence factors including a plasmid-borne type VI secretion system and antimicrobial resistance genes (beta-lactams, fluoroquinolones, and aminoglycoside) were found. The presence of T6SS in a mobile genetic element (plasmid) suggests plausible horizontal transfer of these virulence genes to other organisms. The C. coli YH502 genome also harbors CRISPR sequences and associated proteins. Phylogenetic analysis based on average nucleotide identity and single nucleotide polymorphisms identified closely related C. coli genomes available in the NCBI database. Taken together, the analyzed genomic data of this potentially virulent strain of C. coli will facilitate further understanding of this important foodborne pathogen most likely leading to better control strategies. The chromosome and plasmid sequences of C. coli YH502 have been deposited in GenBank under the accession numbers CP018900.1 and CP018901.1, respectively.

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July 7, 2019

Comparative genome analysis of Lactobacillus plantarum GB-LP3 provides candidates of survival-related genetic factors.

Lactobacillus plantarum is found in various environmental niches such as in the gastrointestinal tract of an animal host or a fermented food. This species isolated from a certain environment is known to possess a variety of properties according to inhabited environment’s adaptation. However, a causal relationship of a genetic factor and phenotype affected by a specific environment has not been systematically comprehended. L. plantarum GB-LP3 strain was isolated from Korean traditional fermented vegetable and the whole genome of GB-LP3 was sequenced. Comparative genome analysis of GB-LP3, with other 14 L. plantarum strains, was conducted. In addition, genomic island regions were investigated. The assembled whole GB-LP3 genome contained a single circular chromosome of 3,206,111bp with the GC content of 44.7%. In the phylogenetic tree analysis, GB-LP3 was in the closest distance from ZJ316. The genomes of GB-LP3 and ZJ316 have the high level of synteny. Functional genes that are related to prophage, bacteriocin, and quorum sensing were found through comparative genomic analysis with ZJ316 and investigation of genomic islands. dN/dS analysis identified that the gene coding for phosphonate ABC transporter ATP-binding protein is evolutionarily accelerated in GB-LP3. Our study found that potential candidate genes that are affected by environmental adaptation in Korea traditional fermented vegetable. Copyright © 2017. Published by Elsevier B.V.

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July 7, 2019

Insight into potential probiotic markers predicted in Lactobacillus pentosus MP-10 genome sequence.

Lactobacillus pentosus MP-10 is a potential probiotic lactic acid bacterium originally isolated from naturally fermented Aloreña green table olives. The entire genome sequence was annotated to in silico analyze the molecular mechanisms involved in the adaptation of L. pentosus MP-10 to the human gastrointestinal tract (GIT), such as carbohydrate metabolism (related with prebiotic utilization) and the proteins involved in bacteria-host interactions. We predicted an arsenal of genes coding for carbohydrate-modifying enzymes to modify oligo- and polysaccharides, such as glycoside hydrolases, glycoside transferases, and isomerases, and other enzymes involved in complex carbohydrate metabolism especially starch, raffinose, and levan. These enzymes represent key indicators of the bacteria’s adaptation to the GIT environment, since they involve the metabolism and assimilation of complex carbohydrates not digested by human enzymes. We also detected key probiotic ligands (surface proteins, excreted or secreted proteins) involved in the adhesion to host cells such as adhesion to mucus, epithelial cells or extracellular matrix, and plasma components; also, moonlighting proteins or multifunctional proteins were found that could be involved in adhesion to epithelial cells and/or extracellular matrix proteins and also affect host immunomodulation. In silico analysis of the genome sequence of L. pentosus MP-10 is an important initial step to screen for genes encoding for proteins that may provide probiotic features, and thus provides one new routes for screening and studying this potentially probiotic bacterium.

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July 7, 2019

A genome-scale metabolic reconstruction of Lysinibacillus sphaericus unveils unexploited biotechnological potentials.

The toxic lineage (TL) of Lysinibacillus sphaericus has been extensively studied because of its potential biotechnological applications in biocontrol of mosquitoes and bioremediation of toxic metals. We previously proposed that L. sphaericus TL should be considered as a novel species based on a comparative genomic analysis. In the current work, we constructed the first manually curated metabolic reconstruction for this species on the basis of the available genomes. We elucidated the central metabolism of the proposed species and, beyond confirming the reported experimental evidence with genomic a support, we found insights to propose novel applications and traits to be considered in further studies. The strains belonging to this lineage exhibit a broad repertory of genes encoding insecticidal factors, some of them remain uncharacterized. These strains exhibit other unexploited biotechnological important traits, such as lactonases (quorum quenching), toxic metal resistance, and potential for aromatic compound degradation. In summary, this study provides a guideline for further research aimed to implement this organism in biocontrol and bioremediation. Similarly, we highlighted the unanswered questions to be responded in order to gain a deeper understanding of the L. sphaericus TL biology.

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July 7, 2019

The origin, diversification and adaptation of a major mangrove clade (Rhizophoreae) revealed by whole-genome sequencing

Mangroves invade some very marginal habitats for woody plants—at the interface between land and sea. Since mangroves anchor tropical coastal communities globally, their origin, diversification and adaptation are of scientific significance, particularly at a time of global climate change. In this study, a combination of single-molecule long reads and the more conventional short reads are generated from Rhizophora apiculata for the de novo assembly of its genome to a near chromosome level. The longest scaffold, N50 and N90 for the R. apiculata genome, are 13.3 Mb, 5.4 Mb and 1.0 Mb, respectively. Short reads for the genomes and transcriptomes of eight related species are also generated. We find that the ancestor of Rhizophoreae experienced a whole-genome duplication ~70 Myrs ago, which is followed rather quickly by colonization and species diversification. Mangroves exhibit pan-exome modifications of amino acid (AA) usage as well as unusual AA substitutions among closely related species. The usage and substitution of AAs, unique among plants surveyed, is correlated with the rapid evolution of proteins in mangroves. A small subset of these substitutions is associated with mangroves’ highly specialized traits (vivipary and red bark) thought to be adaptive in the intertidal habitats. Despite the many adaptive features, mangroves are among the least genetically diverse plants, likely the result of continual habitat turnovers caused by repeated rises and falls of sea level in the geologically recent past. Mangrove genomes thus inform about their past evolutionary success as well as portend a possibly difficult future.

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July 7, 2019

Complete genome sequence of the Bifidobacterium animalis subspecies lactis BL3, preventive probiotics for acute colitis and colon cancer.

We report the genome sequence of Bifidobacterium animalis subspecies lactis BL3, which has preventive properties on acute colitis and colon cancer. The genome of BL3, which was isolated from Korean faeces, consisted of a 1 944 323 bp size single chromosome, and its G+C content was 60.5%. Genome comparison against the closest Bifidobacterium animalis strain revealed that BL3 had particularly different regions of four areas encoding flavin-nucleotide-binding protein, transposase, multidrug ABC transporter and ATP binding protein.

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July 7, 2019

Complete genome sequence and bioinformatics analyses of Bacillus thuringiensis strain BM-BT15426.

This study aimed to investigate the genetic characteristics of Bacillus thuringiensis strain BM-BT15426.B. thuringiensis strain was identified by sequencing the PCR product (amplifying 16S rRNA gene) using ABI Prism 377 DNA Sequencer. The genome was sequenced using PacBio RS II sequencers and assembled de novo using HGAP. Also, further genome annotation was performed.The genome of B. thuringiensis strain BM-BT15426 has a length of 5,246,329 bp and contains 5409 predicted genes with an average G + C content of 35.40%. Three genes were involved in the “Infectious diseases: Amoebiasis” pathway. A total of 21 virulence factors and 9 antibiotic resistant genes were identified.The major pathogenic factors of B. thuringiensis strain BM-BT15426 were identified through complete genome sequencing and bioinformatics analyses which contributes to further study on pathogenic mechanism and phenotype of B. thuringiensis. Copyright © 2017 Elsevier Ltd. All rights reserved.

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