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July 7, 2019

Rapid and affordable size-selected PacBio single-molecule real-time sequencing template library construction using the bead-beating DNA extraction method

This study demonstrated that bead-beating method facilitates a simple and rapid protocol for genomic DNA isolation for Pacific BioSciences (PacBio) sequencing with library construction of sufficient length. The protocol may also be beneficial for inactivating pathogens by simultaneous and instant DNA fragmentation, with no special equipment required to obtain large DNA fragments. This protocol was comparable in terms of quality to the standard protocol suggested by PacBioand represents an alternative, rapid shortcut for performing accurate PacBio sequencing.


July 7, 2019

Genomics of Helicobacter pylori

As Helicobacter pylori infects half the world’s population and displays an extensive intraspecies diversity, genomics is a powerful tool to understand evolution and disease, to identify factors that confer higher risk of severe sequelae, and to find new approaches for therapy both among bacterial and host targets. In line with these objectives, this review article summarizes the major findings in Helicobacter genomics in papers published between April 2016 and March 2017.


July 7, 2019

Novel multiresistance cfr plasmids in linezolid-resistant methicillin-resistant Staphylococcus epidermidis and vancomycin-resistant Enterococcus faecium (VRE) from a hospital outbreak: co-location of cfr and optrA in VRE.

Linezolid is often the drug of last resort to treat infections caused by Gram-positive cocci. Linezolid resistance can be mutational (23S rRNA or L-protein) or, less commonly, acquired [predominantly cfr, conferring resistance to phenicols, lincosamides, oxazolidinones, pleuromutilins and streptogramin A compounds (PhLOPSA) or optrA, encoding oxazolidinone and phenicol resistance].To investigate the clonality and genetic basis of linezolid resistance in 13 linezolid-resistant (LZDR) methicillin-resistant Staphylococcus epidermidis (MRSE) isolates recovered during a 2013/14 outbreak in an ICU in an Irish hospital and an LZDR vancomycin-resistant Enterococcus faecium (VRE) isolate from an LZDR-MRSE-positive patient.All isolates underwent PhLOPSA susceptibility testing, 23S rRNA sequencing, DNA microarray profiling and WGS.All isolates exhibited the PhLOPSA phenotype. The VRE harboured cfr and optrA on a novel 73?kb plasmid (pEF12-0805) also encoding erm(A), erm(B), lnu(B), lnu(E), aphA3 and aadE. One MRSE (M13/0451, from the same patient as the VRE) harboured cfr on a novel 8.5?kb plasmid (pSEM13-0451). The remaining 12 MRSE lacked cfr but exhibited linezolid resistance-associated mutations and were closely related to (1-52 SNPs) but distinct from M13/0451 (202-223 SNPs).Using WGS, novel and distinct cfr and cfr/optrA plasmids were identified in an MRSE and VRE isolate, respectively, as well as a cfr-negative LZDR-MRSE ICU outbreak and a distinct cfr-positive LZDR-MRSE from the same ICU. To our knowledge, this is the first report of cfr and optrA on a single VRE plasmid. Ongoing surveillance of linezolid resistance is essential to maintain its therapeutic efficacy.© The Author 2017. Published by Oxford University Press on behalf of the British Society for Antimicrobial Chemotherapy. All rights reserved. For Permissions, please email: journals.permissions@oup.com.


July 7, 2019

Complete genome analysis of Lactobacillus fermentum SK152 from kimchi reveals genes associated with its antimicrobial activity.

Research findings on probiotics highlight their importance in repressing harmful bacteria, leading to more extensive research on their potential applications. We analysed the genome of Lactobacillus fermentum SK152, which was isolated from the Korean traditional fermented vegetable dish kimchi, to determine the genetic makeup and genetic factors responsible for the antimicrobial activity of L. fermentum SK152 and performed a comparative genome analysis with other L. fermentum strains. The genome of L. fermentum SK152 was found to comprise a complete circular chromosome of 2092 273 bp, with an estimated GC content of 51.9% and 2184 open reading frames. It consisted of 2038 protein-coding genes and 73 RNA-coding genes. Moreover, a gene encoding a putative endolysin was found. A comparative genome analysis with other L. fermentum strains showed that SK152 is closely related to L. fermentum 3872 and F-6. An evolutionary analysis identified five positively selected genes that encode proteins associated with transport, survival and stress resistance. These positively selected genes may be essential for L. fermentum to colonise and survive in the stringent environment of the human gut and exert its beneficial effects. Our findings highlight the potential benefits of SK152.© FEMS 2017. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.


July 7, 2019

Complete mitochondrial genome sequence of Aspergillus oryzae RIB 127 and its comparative analysis with related species

Here, we determined the complete sequence and annotation of the mitochondrial genome of A. oryzae (strain RIB 127). The complete mitochondrial genome is 29,202 base pairs (bp), with low GC content of 26.2%. Conserved genes identified include 26 transfer RNAs, the small and large ribosomal RNA subunits, and 14 protein-coding genes. Phylogenetic analysis based on the complete mitochondrial genome revealed that RIB 127 formed a single clade with two other A. oryzae species.


July 7, 2019

Quantitative proteomics for the comprehensive analysis of stress responses of Lactobacillus paracasei subsp. paracasei F19.

Lactic acid bacteria are broadly employed as starter cultures in the manufacture of foods. Upon technological preparation, they are confronted with drying stress that amalgamates numerous stress conditions resulting in losses of fitness and survival. To better understand and differentiate physiological stress responses, discover general and specific markers for the investigated stress conditions, and predict optimal preconditioning for starter cultures, we performed a comprehensive genomic and quantitative proteomic analysis of a commonly used model system, Lactobacillus paracasei subsp. paracasei TMW 1.1434 (isogenic with F19) under 11 typical stress conditions, including among others oxidative, osmotic, pH, and pressure stress. We identified and quantified >1900 proteins in triplicate analyses, representing 65% of all genes encoded in the genome. The identified genes were thoroughly annotated in terms of subcellular localization prediction and biological functions, suggesting unbiased and comprehensive proteome coverage. In total, 427 proteins were significantly differentially expressed in at least one condition. Most notably, our analysis suggests that optimal preconditioning toward drying was predicted to be alkaline and high-pressure stress preconditioning. Taken together, we believe the presented strategy may serve as a prototypic example for the analysis and utility of employing quantitative-mass-spectrometry-based proteomics to study bacterial physiology.


July 7, 2019

The Tartary buckwheat genome provides insights into rutin biosynthesis and abiotic stress tolerance.

Tartary buckwheat (Fagopyrum tataricum) is an important pseudocereal crop that is strongly adapted to growth in adverse environments. Its gluten-free grain contains complete proteins with a well-balanced composition of essential amino acids and is a rich source of beneficial phytochemicals that provide significant health benefits. Here, we report a high-quality, chromosome-scale Tartary buckwheat genome sequence of 489.3 Mb that is assembled by combining whole-genome shotgun sequencing of both Illumina short reads and single-molecule real-time long reads, sequence tags of a large DNA insert fosmid library, Hi-C sequencing data, and BioNano genome maps. We annotated 33 366 high-confidence protein-coding genes based on expression evidence. Comparisons of the intra-genome with the sugar beet genome revealed an independent whole-genome duplication that occurred in the buckwheat lineage after they diverged from the common ancestor, which was not shared with rosids or asterids. The reference genome facilitated the identification of many new genes predicted to be involved in rutin biosynthesis and regulation, aluminum stress resistance, and in drought and cold stress responses. Our data suggest that Tartary buckwheat’s ability to tolerate high levels of abiotic stress is attributed to the expansion of several gene families involved in signal transduction, gene regulation, and membrane transport. The availability of these genomic resources will facilitate the discovery of agronomically and nutritionally important genes and genetic improvement of Tartary buckwheat. Copyright © 2017 The Author. Published by Elsevier Inc. All rights reserved.


July 7, 2019

Evaluation of nine popular de novo assemblers in microbial genome assembly.

Next generation sequencing (NGS) technologies are revolutionizing biology, with Illumina being the most popular NGS platform. Short read assembly is a critical part of most genome studies using NGS. Hence, in this study, the performance of nine well-known assemblers was evaluated in the assembly of seven different microbial genomes. Effect of different read coverage and k-mer parameters on the quality of the assembly were also evaluated on both simulated and actual read datasets. Our results show that the performance of assemblers on real and simulated datasets could be significantly different, mainly because of coverage bias. According to outputs on actual read datasets, for all studied read coverages (of 7×, 25× and 100×), SPAdes and IDBA-UD clearly outperformed other assemblers based on NGA50 and accuracy metrics. Velvet is the most conservative assembler with the lowest NGA50 and error rate. Copyright © 2017. Published by Elsevier B.V.


July 7, 2019

Analysis of resistance genes in pan-resistant Myroides odoratimimus clinical strain PR63039 using whole genome sequencing.

To clarify the antibiotic resistance mechanisms of Myroides odoratimimus, pan-resistant M. odoratimimus strain PR63039 was isolated and its genome sequenced and analyzed. Antimicrobial susceptibility testing was conducted using the Kirby-Bauer disk diffusion method, and the Phoenix-100 Automated Microbiology System with a NMIC/ID-4 panel including aminoglycosides, ß-lactams, polypeptides, quinolones, sulfonamides, chloramphenicols, and tetracyclines. Single-molecule real-time whole genome sequencing was conducted using the PacBio RSII system, and genome annotation was performed using RAST and IMG ER. To characterize the genome features, a number of databases and software programs, including GC-Profile, CG viewer, the VFDB database, ISfinder, RADB, CARD, ResFinder, and PHAST, were used. M. odoratimimus isolate PR63039 was resistant to almost all antibiotics tested, suggesting pan-drug resistance. The genome consisted of a 4,366,950-bp chromosome and a 90,798-bp plasmid (p63039), which contained a large number of resistance genes and virulence factors. The distribution of the resistance genes was distinctive, and a resistance region, designated MY63039-RR, was identified. RAST analysis indicated that 108 of the annotated genes were potentially involved in virulence, disease, and defense, all of which could be associated with resistance and pathogenicity. Prophage analysis also identified two incomplete prophages in the genome of M. odoratimimus PR63039. Multiple antibiotic-resistance genes were identified, including those associated with resistance to tetracycline (tetX), macrolides (ereB, cfrA, lasE), sulfonamides (sul2, sul3), ß-lactams (blaMUS-1, blaTUS-1, blaSFB-1, blaSLB-1, blaOXA-209, blaOXA-347), and chloramphenicol (cat). Further, the presence of 18 antibiotic efflux pump-encoding resistance genes, including acrB, acrD, acrF, adeB, adeG, adeJ, amrB, ceoB, cmeB, mdsB, mexB, mexD, mexF, mtrD, smeE, mdtF, macB, likely accounts for the observed quinolone resistance of strain PR63039. To the best of our knowledge, this is the first report of the presence of the blaSFB-1, blaSLB-1, blaOXA-209, blaOXA-347, and tetX resistance genes in M. odoratimimus. Copyright © 2017 Elsevier Ltd. All rights reserved.


July 7, 2019

Whole-genome sequencing identification of a multidrug-resistant Salmonella enterica serovar Typhimurium strain carrying blaNDM-5 from Guangdong, China.

A carbapenem-resistant Salmonella enterica serovar Typhimurium (sequence type 34 [ST34]) strain was isolated from a fecal specimen from a child with acute diarrhea. Whole-genome sequencing revealed that the 84.5-kb IncFII plasmid pST41-NDM carrying the NDM-5 carbapenemase gene possesses a structure identical to that of the IncFII-type plasmid backbone. However, the blaNDM-5 flanking sequence found in this plasmid is identical to the blaNDM-5-positive IncX3 plasmids carried by 10 strains of Enterobacteriaceae identified in the same hospital. Copyright © 2017 Elsevier B.V. All rights reserved.


July 7, 2019

The complete genome sequence of Streptomyces albolongus YIM 101047, the producer of novel bafilomycins and odoriferous sesquiterpenoids.

Streptomyces albolongus YIM 101047 produces novel bafilomycins and odoriferous sesquiterpenoids with cytotoxic and antimicrobial activities. Here, we report the complete genome sequence of S. albolongus YIM 101047, which consists of an 8,027,788bp linear chromosome. Forty-six putative biosynthetic gene clusters of secondary metabolites were found. The sesquiterpenoid gene cluster was on the left arm (0.09-0.10Mb), and the bafilomycin biosynthetic gene cluster was on the right arm (7.46-7.64Mb) of the chromosome. Twenty-two putative gene clusters with high or moderate similarity to important antibiotic biosynthetic gene clusters were found, including the antitumor agents bafilomycin, epothilone and hedamycin; the antibacterial/antifungal agents clavulanic acid, collismycin A, frontalamides, kanamycin, streptomycin and streptothricin; the protein phosphatase inhibitor RK-682; and the acute iron poisoning medication desferrioxamine B. The genome sequence reported here will enable us to study the biosynthetic mechanism of these important antibiotics and will facilitate the discovery of novel secondary metabolites with potential applications to human health. Copyright © 2017 Elsevier B.V. All rights reserved.


July 7, 2019

Complete genome sequence of endophyte Bacillus flexus KLBMP 4941 reveals its plant growth promotion mechanism and genetic basis for salt tolerance.

Bacillus flexus KLBMP 4941 is a halotolerant endophyte isolated from the halophyte Limonium sinense. This strain can improve host seedling growth under salt stress conditions. We here report the complete genome information of endophyte KLBMP 4941. It has a circular chromosome and two plasmids for a total genome 4,104,242 bp in size with a G+C content of 38.09%. Genes related to plant growth promotion (PGP), such as those associated with nitrogen fixation, siderophore, spermidine, and acetoin synthesis were found in the KLBMP 4941 genome. Some genes responsible for high salinity tolerance, like genes associated with the Na(+)/H(+) antiporter, glycine betaine transporter, and betaine-aldehyde dehydrogenase were also found in the KLBMP 4941 genome. The genome analysis will provide better understanding of the mechanisms underlying the promotion of plant growth in strain KLBMP 4941 under salt stress conditions and its ability to adapt to coastal salt marsh habitats, and provide a basis for its further biotechnological applications in agriculture. Copyright © 2017 Elsevier B.V. All rights reserved.


July 7, 2019

Comparative whole genome analysis of three consecutive Salmonella diarizonae isolates.

Infections of very young children or immunocompromised people with Salmonella of higher subspecies are a well-known phenomenon often associated with contact to cold-blooded animals. We describe the molecular characterization of three S. enterica subsp. diarizonae strains, isolated consecutively over a period of several months from a hospital patient suffering from diarrhea and sepsis with fatal outcome. With the initial isolate the first complete genome sequence of a member of subsp. diarizonae is provided and based on this reference we revealed the genomic differences between the three isolates by use of next-generation sequencing and confirmed by phenotypical tests. Genome comparisons revealed mutations within gpt, hfq and purK in the first isolate as a sign of clonal variation rather than host-directed evolution. Furthermore, our work demonstrates that S. enterica subsp. diarizonae possess, besides a conserved set of known Salmonella Pathogenicity Islands, a variable portfolio of additional genomic islands of unknown function. Copyright © 2017 Elsevier GmbH. All rights reserved.


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