Menu

Asset Tag: SMRT Sequencing

July 7, 2019

Draft genome sequence of Streptomyces scabrisporus NF3, an endophyte isolated from Amphipterygium adstringens.

We report the draft genome sequence of Streptomyces scabrisporus NF3, an endophyte isolated from Amphipterygium adstringens in Chiapas, Mexico. This strain produces a new modified linaridin peptide. The genome harbors at least 50 gene clusters for synthases of polyketide and nonribosomal peptides, suggesting a prospective production of various secondary metabolites. Copyright © 2017 Vazquez-Hernandez et al.

Read more
July 7, 2019

Evidence for the evolutionary steps leading to mecA-mediated ß-lactam resistance in staphylococci.

The epidemiologically most important mechanism of antibiotic resistance in Staphylococcus aureus is associated with mecA-an acquired gene encoding an extra penicillin-binding protein (PBP2a) with low affinity to virtually all ß-lactams. The introduction of mecA into the S. aureus chromosome has led to the emergence of methicillin-resistant S. aureus (MRSA) pandemics, responsible for high rates of mortality worldwide. Nonetheless, little is known regarding the origin and evolution of mecA. Different mecA homologues have been identified in species belonging to the Staphylococcus sciuri group representing the most primitive staphylococci. In this study we aimed to identify evolutionary steps linking these mecA precursors to the ß-lactam resistance gene mecA and the resistance phenotype. We sequenced genomes of 106 S. sciuri, S. vitulinus and S. fleurettii strains and determined their oxacillin susceptibility profiles. Single-nucleotide polymorphism (SNP) analysis of the core genome was performed to assess the genetic relatedness of the isolates. Phylogenetic analysis of the mecA gene homologues and promoters was achieved through nucleotide/amino acid sequence alignments and mutation rates were estimated using a Bayesian analysis. Furthermore, the predicted structure of mecA homologue-encoded PBPs of oxacillin-susceptible and -resistant strains were compared. We showed for the first time that oxacillin resistance in the S. sciuri group has emerged multiple times and by a variety of different mechanisms. Development of resistance occurred through several steps including structural diversification of the non-binding domain of native PBPs; changes in the promoters of mecA homologues; acquisition of SCCmec and adaptation of the bacterial genetic background. Moreover, our results suggest that it was exposure to ß-lactams in human-created environments that has driven evolution of native PBPs towards a resistance determinant. The evolution of ß-lactam resistance in staphylococci highlights the numerous resources available to bacteria to adapt to the selective pressure of antibiotics.

Read more
July 7, 2019

Updated reference genome sequence and annotation of Mycobacterium bovis AF2122/97.

We report here an update to the reference genome sequence of the bovine tuberculosis bacillus Mycobacterium bovis AF2122/97, generated using an integrative multiomics approach. The update includes 42 new coding sequences (CDSs), 14 modified annotations, 26 single-nucleotide polymorphism (SNP) corrections, and disclosure that the RD900 locus, previously described as absent from the genome, is in fact present. Copyright © 2017 Malone et al.

Read more
July 7, 2019

Whole-genome restriction mapping by “subhaploid”-based RAD sequencing: An efficient and flexible approach for physical mapping and genome scaffolding.

Assembly of complex genomes using short reads remains a major challenge, which usually yields highly fragmented assemblies. Generation of ultradense linkage maps is promising for anchoring such assemblies, but traditional linkage mapping methods are hindered by the infrequency and unevenness of meiotic recombination that limit attainable map resolution. Here we develop a sequencing-based “in vitro” linkage mapping approach (called RadMap), where chromosome breakage and segregation are realized by generating hundreds of “subhaploid” fosmid/bacterial-artificial-chromosome clone pools, and by restriction site-associated DNA sequencing of these clone pools to produce an ultradense whole-genome restriction map to facilitate genome scaffolding. A bootstrap-based minimum spanning tree algorithm is developed for grouping and ordering of genome-wide markers and is implemented in a user-friendly, integrated software package (AMMO). We perform extensive analyses to validate the power and accuracy of our approach in the model plant Arabidopsis thaliana and human. We also demonstrate the utility of RadMap for enhancing the contiguity of a variety of whole-genome shotgun assemblies generated using either short Illumina reads (300 bp) or long PacBio reads (6-14 kb), with up to 15-fold improvement of N50 (~816 kb-3.7 Mb) and high scaffolding accuracy (98.1-98.5%). RadMap outperforms BioNano and Hi-C when input assembly is highly fragmented (contig N50 = 54 kb). RadMap can capture wide-range contiguity information and provide an efficient and flexible tool for high-resolution physical mapping and scaffolding of highly fragmented assemblies. Copyright © 2017 Dou et al.

Read more
July 7, 2019

Complete genome sequence of Burkholderia stabilis FERMP-21014.

Cholesterol esterase (EC 3.1.1.13) was identified in a bacterium, Burkholderia stabilis strain FERMP-21014. Here, we report the complete genome sequence of B. stabilis FERMP-21014, which has been used in the commercial production of cholesterol esterase. The genome sequence information may be useful for improving production levels of cholesterol esterase. Copyright © 2017 Konishi et al.

Read more
July 7, 2019

Reclassification of the specialized metabolite producer Pseudomonas mesoacidophila ATCC 31433 as a member of the Burkholderia cepacia complex.

Pseudomonas mesoacidophila ATCC 31433 is a Gram-negative bacterium, first isolated from Japanese soil samples, that produces the monobactam isosulfazecin and the ß-lactam-potentiating bulgecins. To characterize the biosynthetic potential of P. mesoacidophila ATCC 31433, its complete genome was determined using single-molecule real-time DNA sequence analysis. The 7.8-Mb genome comprised four replicons, three chromosomal (each encoding rRNA) and one plasmid. Phylogenetic analysis demonstrated that P. mesoacidophila ATCC 31433 was misclassified at the time of its deposition and is a member of the Burkholderia cepacia complex, most closely related to Burkholderia ubonensis The sequenced genome shows considerable additional biosynthetic potential; known gene clusters for malleilactone, ornibactin, isosulfazecin, alkylhydroxyquinoline, and pyrrolnitrin biosynthesis and several uncharacterized biosynthetic gene clusters for polyketides, nonribosomal peptides, and other metabolites were identified. Furthermore, P. mesoacidophila ATCC 31433 harbors many genes associated with environmental resilience and antibiotic resistance and was resistant to a range of antibiotics and metal ions. In summary, this bioactive strain should be designated B. cepacia complex strain ATCC 31433, pending further detailed taxonomic characterization.IMPORTANCE This work reports the complete genome sequence of Pseudomonas mesoacidophila ATCC 31433, a known producer of bioactive compounds. Large numbers of both known and novel biosynthetic gene clusters were identified, indicating that P. mesoacidophila ATCC 31433 is an untapped resource for discovery of novel bioactive compounds. Phylogenetic analysis demonstrated that P. mesoacidophila ATCC 31433 is in fact a member of the Burkholderia cepacia complex, most closely related to the species Burkholderia ubonensis Further investigation of the classification and biosynthetic potential of P. mesoacidophila ATCC 31433 is warranted. Copyright © 2017 Loveridge et al.

Read more
July 7, 2019

Synergistic interaction between phage therapy and antibiotics clears Pseudomonas aeruginosa infection in endocarditis and reduces virulence.

Increasing antibiotic resistance warrants therapeutic alternatives. Here we investigated the efficacy of bacteriophage-therapy (phage) alone or combined with antibiotics against experimental endocarditis (EE) due to Pseudomonas aeruginosa, an archetype of difficult-to-treat infection.In vitro fibrin clots and rats with aortic EE were treated with an antipseudomonas phage cocktail alone or combined with ciprofloxacin. Phage pharmacology, therapeutic efficacy, and resistance were determined.In vitro, single-dose phage therapy killed 7 log colony-forming units (CFUs)/g of fibrin clots in 6 hours. Phage-resistant mutants regrew after 24 hours but were prevented by combination with ciprofloxacin (2.5 × minimum inhibitory concentration). In vivo, single-dose phage therapy killed 2.5 log CFUs/g of vegetations in 6 hours (P < .001 vs untreated controls) and was comparable with ciprofloxacin monotherapy. Moreover, phage/ciprofloxacin combinations were highly synergistic, killing >6 log CFUs/g of vegetations in 6 hours and successfully treating 64% (n = 7/11) of rats. Phage-resistant mutants emerged in vitro but not in vivo, most likely because resistant mutations affected bacterial surface determinants important for infectivity (eg, the pilT and galU genes involved in pilus motility and LPS formation).Single-dose phage therapy was active against P. aeruginosa EE and highly synergistic with ciprofloxacin. Phage-resistant mutants had impaired infectivity. Phage-therapy alone or combined with antibiotics merits further clinical consideration.

Read more
July 7, 2019

Staphylococcus aureus CC395 harbours a novel composite staphylococcal cassette chromosome mec element.

CoNS species are likely reservoirs of the staphylococcal cassette chromosome mec (SCC mec ) in Staphylococcus aureus . S . aureus CC395 is unique as it is capable of exchanging DNA with CoNS via bacteriophages, which are also known to mediate transfer of SCC mec .To analyse the structure and putative origin of the SCC mec element in S . aureus CC395.The only MRSA CC395 strain described in the literature, JS395, was subjected to WGS, and its SCC mec element was compared with those found in CoNS species and other S. aureus strains.JS395 was found to carry an unusually large 88 kb composite SCC mec element. The 33 kb region downstream of orfX harboured a type V SCC mec element and a CRISPR locus, which was most similar to those found in the CoNS species Staphylococcus capitis and Staphylococcus schleiferi . A 55 kb SCC element was identified downstream of the type V SCC mec element and contained a mercury resistance region found in the composite SCC element of some Staphylococcus epidermidis and S . aureus strains, an integrated S . aureus plasmid containing genes for the detoxification of cadmium and arsenic, and a stretch of genes that was partially similar to the type IVg SCC mec element found in a bovine S . aureus strain.The size and complexity of the SCC mec element support the idea that CC395 is highly prone to DNA uptake from CoNS. Thus CC395 may serve as an entry point for SCC mec and SCC structures into S . aureus .

Read more
July 7, 2019

Draft nuclear genome sequence of the liquid hydrocarbon–accumulating green microalga Botryococcus braunii race B (Showa).

Botryococcus braunii has long been known as a prodigious producer of liquid hydrocarbon oils that can be converted into combustion engine fuels. This draft genome for the B race of B. braunii will allow researchers to unravel important hydrocarbon biosynthetic pathways and identify possible regulatory networks controlling this unusual metabolism. Copyright © 2017 Browne et al.

Read more
July 7, 2019

Whole-genome comparative analysis of Salmonella enterica serovar Newport strains reveals lineage-specific divergence.

Salmonella enterica subsp. enterica serovar Newport has been associated with various foodborne outbreaks in humans and animals. Phylogenetically, serovar Newport is one of several Salmonella serovars that are polyphyletic. To understand more about the polyphyletic nature of this serovar, six food, environment, and human isolates from different Newport lineages were selected for genome comparison analyses. Whole genome comparisons demonstrated that heterogeneity mostly occurred in the prophage regions. Lineage-specific characteristics were also present in the Salmonella pathogenicity islands and fimbrial operons. Published by Oxford University Press on behalf of the Society for Molecular Biology and Evolution 2017. This work is written by US Government employees and is in the public domain in the US.

Read more
July 7, 2019

Genome sequence of Acinetobacter lactucae OTEC-02, isolated from hydrocarbon-contaminated soil.

Acinetobacter lactucae OTEC-02 was isolated from hydrocarbon-contaminated soils. Whole-genome sequence analysis was performed to learn more about the strain’s ability to degrade different types of recalcitrant toxic monoaromatic hydrocarbons. The genome of this bacterium revealed its genomic properties and versatile metabolic features, as well as a complete prophage. Copyright © 2017 Rogel-Hernandez et al.

Read more
July 7, 2019

Multiple genome sequences of heteropolysaccharide-forming acetic acid bacteria.

We report here the complete genome sequences of the acetic acid bacteria (AAB) Acetobacter aceti TMW 2.1153, A. persici TMW 2.1084, and Neoasaia chiangmaiensis NBRC 101099, which secrete biotechnologically relevant heteropolysaccharides (HePSs) into their environments. Upon genome sequencing of these AAB strains, the corresponding HePS biosynthesis pathways were identified. Copyright © 2017 Brandt et al.

Read more
July 7, 2019

Three novel species with peptidoglycan cell walls form the new genus Lacunisphaera gen. nov. in the family Opitutaceae of the verrucomicrobial subdivision 4.

The cell wall of free-living bacteria consists of peptidoglycan (PG) and is critical for maintenance of shape as dissolved solutes cause osmotic pressure and challenge cell integrity. Surprisingly, the subdivision 4 of the phylum Verrucomicrobia appears to be exceptional in this respect. Organisms of this subdivision are described to be devoid of muramic or diaminopimelic acid (DAP), usually found as components of PG in bacterial cell walls. Here we describe three novel bacterial strains from a freshwater lake, IG15(T), IG16b(T), and IG31(T), belonging to a new genus in the subdivision 4 of Verrucomicrobia which we found to possess PG as part of their cell walls. Biochemical analysis revealed the presence of DAP not only in these novel strains, but also in Opitutus terrae PB90-1(T), the closest described relative of strains IG15(T), IG16b(T), and IG31(T). Furthermore, we found that nearly all genes necessary for peptidoglycan synthesis are present in genomes of subdivision 4 members, as well as in the complete genome sequence of strain IG16b(T). In addition, we isolated and visualized PG-sacculi for strain IG16b(T). Thus, our results challenge the concept of peptidoglycan-less free-living bacteria. Our polyphasic taxonomy approach places the novel strains in a new genus within the family Opitutaceae, for which the name Lacunisphaera gen. nov. is proposed. Strain designations for IG15(T), IG16b(T) and IG31(T) are Lacunisphaera parvula sp. nov. (=DSM 26814 = LMG 29468), L. limnophila sp. nov. (=DSM 26815 = LMG 29469) and L. anatis sp. nov. (=DSM 103142 = LMG 29578) respectively, with L. limnophila IG16b(T) being the type species of the genus.

Read more
July 7, 2019

Chromosomal 16S ribosomal RNA methyltransferase RmtE1 in Escherichia coli sequence type 448.

We identified rmtE1, an uncommon 16S ribosomal methyltransferase gene, in an aminoglycoside- and cephalosporin-resistant Escherichia coli sequence type 448 clinical strain co-harboring blaCMY-2. Long-read sequencing revealed insertion of a 101,257-bp fragment carrying both resistance genes to the chromosome. Our findings underscore E. coli sequence type 448 as a potential high-risk multidrug-resistant clone.

Read more
July 7, 2019

Characterization of potential polysaccharide utilization systems in the marine bacteroidetes Gramella flava JLT2011 using a multi-omics approach.

Members of phylum Bacteroidetes are distributed across diverse marine niches and Flavobacteria is often the predominant bacterial class decomposing algae-derived polysaccharides. Here, we report the complete genome of Gramella flava JLT2011 (Flavobacteria) isolated from surface water of the southeastern Pacific. A remarkable genomic feature is that the number of glycoside hydrolase (GH) genes in the genome of G. flava JLT2011 is more than 2-fold higher than that of other Gramella species. The functional profiles of the GHs suggest extensive variation in Gramella species. Growth experiments revealed that G. flava JLT2011 has the ability to utilize a wide range of polysaccharides for growth such as xylan and homogalacturonan in pectin. Nearly half of all GH genes were located on the multi-gene polysaccharide utilization loci (PUL) or PUL-like systems in G. flava JLT2011. This species was also found to harbor the two xylan PULs and a pectin PUL, respectively. Gene expression data indicated that more GHs and sugar-specific outer-membrane susC-susD systems were found in the presence of xylan than in the presence of pectin, suggesting a different strategy for heteropolymeric xylan and homoglacturonan utilization. Multi-omics data (transcriptomics, proteomics, and metabolomics) indicated that xylan PULs and pectin PUL are respectively involved in the catabolism of their corresponding polysaccharides. This work presents a comparison of polysaccharide decomposition within a genus and expands current knowledge on the diversity and function of PULs in marine Bacteroidetes, thereby deepening our understanding of their ecological role in polysaccharide remineralization in the marine system.

Read more

Subscribe for blog updates:

Talk with an expert

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.