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Asset Tag: Bacterial genome

July 7, 2019

Genome misclassification of Klebsiella variicola and Klebsiella quasipneumoniae isolated from plants, animals and humans

Objective. Due to the fact that K. variicola, K. quasipneumoniae and K. pneumoniae are closely related bacterial species, misclassification can occur due to mistakes either in normal biochemical tests or during submission to public databases. The objective of this work was to identify K. variicola and K. quasipneumoniae genomes misclassified in GenBank database. Materials and methods. Both rpoB phylogenies and average nucleotide identity (ANI) were used to identify a significant number of misclassified Klebsiella spp. genomes. Results. Here we report an update of K. variicola and K. quasipneumoniae genomes correctly classified and a list of isolated genomes obtained from humans, plants, animals and insects, described originally as K. pneumoniae or K. variicola, but known now to be misclassified. Conclusions. This work contributes to recognize the extensive presence of K. variicola and K. quasipneumoniae isolates in diverse sites and samples.

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July 7, 2019

COSINE: non-seeding method for mapping long noisy sequences.

Third generation sequencing (TGS) are highly promising technologies but the long and noisy reads from TGS are difficult to align using existing algorithms. Here, we present COSINE, a conceptually new method designed specifically for aligning long reads contaminated by a high level of errors. COSINE computes the context similarity of two stretches of nucleobases given the similarity over distributions of their short k-mers (k = 3-4) along the sequences. The results on simulated and real data show that COSINE achieves high sensitivity and specificity under a wide range of read accuracies. When the error rate is high, COSINE can offer substantial advantages over existing alignment methods.© The Author(s) 2017. Published by Oxford University Press on behalf of Nucleic Acids Research.

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July 7, 2019

Comparative whole-genomic analysis of an ancient L2 lineage Mycobacterium novel phylogenetic clade and common genetic determinants of hypervirulent strains.

Background: Development of improved therapeutics against tuberculosis (TB) is hindered by an inadequate understanding of the relationship between disease severity and genetic diversity of its causative agent, Mycobacterium tuberculosis. We previously isolated a hypervirulent M. tuberculosis strain H112 from an HIV-negative patient with an aggressive disease progression from pulmonary TB to tuberculous meningitis—the most severe manifestation of tuberculosis. Human macrophage challenge experiment demonstrated that the strain H112 exhibited significantly better intracellular survivability and induced lower level of TNF-a than the reference virulent strain H37Rv and other 123 clinical isolates. Aim: The present study aimed to identify the potential genetic determinants of mycobacterial virulence that were common to strain H112 and hypervirulent M. tuberculosis strains of the same phylogenetic clade isolated in other global regions. Methods: A low-virulent M. tuberculosis strain H54 which belonged to the same phylogenetic lineage (L2) as strain H112 was selected from a collection of 115 clinical isolates. Both H112 and H54 were whole-genome-sequenced using PacBio sequencing technology. A comparative genomics approach was adopted to identify mutations present in strain H112 but absent in strain H54. Subsequently, an extensive phylogenetic analysis was conducted by including all publically available M. tuberculosis genomes. Single-nucleotide-polymorphisms (SNPs) and structural variations (SVs) common to hypervirulent strains in the global collection of genomes were considered as potential genetic determinants of hypervirulence. Results: Sequencing data revealed that both H112 and H54 were identified as members of the same sub-lineage L2.2.1. After excluding the lineage-related mutations shared between H112 and H54, we analyzed the phylogenetic relatedness of H112 with global collection of M. tuberculosis genomes (n = 4,338), and identified a novel phylogenetic clade in which four hypervirulent strains isolated from geographically diverse regions were clustered together. All hypervirulent strains in the clade shared 12 SNPs and 5 SVs with H112, including those affecting key virulence-associated loci, notably, a deleterious SNP (rv0178 p. D150E) within mce1 operon and an intergenic deletion (854259_ 854261delCC) in close-proximity to phoP. Conclusion: The present study identified common genetic factors in a novel phylogenetic clade of hypervirulent M. tuberculosis. The causative role of these mutations in mycobacterial virulence should be validated in future study.

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July 7, 2019

De novo design and synthesis of a 30-cistron translation-factor module.

Two of the many goals of synthetic biology are synthesizing large biochemical systems and simplifying their assembly. While several genes have been assembled together by modular idempotent cloning, it is unclear if such simplified strategies scale to very large constructs for expression and purification of whole pathways. Here we synthesize from oligodeoxyribonucleotides a completely de-novo-designed, 58-kb multigene DNA. This BioBrick plasmid insert encodes 30 of the 31 translation factors of the PURE translation system, each His-tagged and in separate transcription cistrons. Dividing the insert between three high-copy expression plasmids enables the bulk purification of the aminoacyl-tRNA synthetases and translation factors necessary for affordable, scalable reconstitution of an in vitro transcription and translation system, PURE 3.0.© The Author(s) 2017. Published by Oxford University Press on behalf of Nucleic Acids Research.

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July 7, 2019

Nitrogen fixation genes and nitrogenase activity of the non-heterocystous cyanobacterium Thermoleptolyngbya sp. O-77.

Cyanobacteria are widely distributed in marine, aquatic, and terrestrial ecosystems, and play an important role in the global nitrogen cycle. In the present study, we examined the genome sequence of the thermophilic non-heterocystous N2-fixing cyanobacterium, Thermoleptolyngbya sp. O-77 (formerly known as Leptolyngbya sp. O-77) and characterized its nitrogenase activity. The genome of this cyanobacterial strain O-77 consists of a single chromosome containing a nitrogen fixation gene cluster. A phylogenetic analysis indicated that the NifH amino acid sequence from strain O-77 was clustered with those from a group of mesophilic species: the highest identity was found in Leptolyngbya sp. KIOST-1 (97.9% sequence identity). The nitrogenase activity of O-77 cells was dependent on illumination, whereas a high intensity of light of 40 µmol m-2 s-1 suppressed the effects of illumination.

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July 7, 2019

The draft genome sequence of Pectobacterium carotovorum subsp. actinidiae KKH3 that infects kiwi plant and potential bioconversion applications

Pectobacterium carotovorum subsp. actinidiae KKH3 is an Enterobacteriaceae bacterial pathogen that infects kiwi plants, causing canker-like symptoms that pose a threat to the kiwifruit industry. Because the strain was originally isolated from woody plants and possesses numerous plant cell wall-degrading enzymes, this draft genome report provides insight into possible bioconversion applications, as well as a better understanding of this important plant pathogen.

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July 7, 2019

Complete genome sequence of Spirosoma pulveris JSH 5-14 T, a bacterium isolated from a dust sample

Dust particles from the deserts and semiarid lands in northern China cause pollution that increase the burden of allergic disease particularly in the urban population of East Asia. Dust particles that carried with windstorm are associated with microbial populations, which include virus, bacteria, and fungi. Spirosoma pulveris JSH 5-14T isolated from the gamma ray-irradiated dust sample collected at Nonsan, Chungnam province, South Korea and showed resistance against gamma and UV radiation. We carried out the whole genome sequencing to understand insight of radiation resistance and their mechanisms of survival. The whole genome of strain JSH 5-14T is comprised of 7,188,680 bp (G+C content of 50.50%) including 5,896 protein-coding genes and 52 RNA genes. The genome analysis of strain JSH 5-14T showed the presence of several genes involved in DNA repair pathways and defense mechanism against irradiation. In this study, we discuss the implication of such findings concerning other radiation resistant bacteria.

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July 7, 2019

Lactobacillus allii sp. nov. isolated from scallion kimchi.

A novel strain of lactic acid bacteria, WiKim39T, was isolated from a scallion kimchi sample consisting of fermented chili peppers and vegetables. The isolate was a Gram-positive, rod-shaped, non-motile, catalase-negative and facultatively anaerobic lactic acid bacterium. Phylogenetic analysis of the 16S rRNA gene sequence showed that strain WiKim39T belonged to the genus Lactobacillus, and shared 97.1-98.2?%?pair-wise sequence similarities with related type strains, Lactobacillus nodensis, Lactobacillus insicii, Lactobacillus versmoldensis, Lactobacillus tucceti and Lactobacillus furfuricola. The G+C?content of the strain based on its genome sequence was 35.3?mol%. The ANI values between WiKim39T and the closest relatives were lower than 80?%. Based on the phenotypic, biochemical, and phylogenetic analyses, strain WiKim39T represents a novel species of the genus Lactobacillus, for which the name Lactobacillus allii sp. nov. is proposed. The type strain is WiKim39T (=KCTC 21077T=JCM 31938T).

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July 7, 2019

Systems biology analysis of the key genes of surfactin production in Bacillus subtilis MJ01 (isolated from soil contaminated oil in south of Iran), spizizenii, and 168 isolates

Applying microorganism in oil recovery has attracted attentions recently. Surfactin produced by Bacillus subtilis is widely used industrially in a range of industrial applications in pharmecutical and environmental sectors. Little information about molecular mechanism of suffactin compound is available. In this study, we performed promoter and network analysis of surfactin production genes in Bacillus subtilis subsp. MJ01 (isolated from oil contaminated soil in South of Iran), spizizenii and 168. Our analysis revealed that comQ and comX are the genes with sequence alterations among these three strains of Bacillus subtilis and are involved in surfactin production. Promoter analysis indicated that lrp, argR, rpoD, purr and ihf are overrepresented and have the highest number of transcription factor binding sites (TFBs) on the key surfactin production genes in all 3 strains. Also the pattern of TFBs among these three strains was completely different. Interestingly, there is distinct difference between 168, spizizenii and MJ01 in their frequency of TFs that activate genes involve in surfactin production. Attribute weighting algorithms and decision tree analysis revealed ihf, rpoD and flHCD as the most important TF among surfactin production. Network analysis identified two significant network modules. The first one consists of key genes involved in surfactin production and the second module includes key TFs, involved in regulation of surfactin production. Our findings enhance understanding the molecular mechanism of surfactin production through systems biology analysis.

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July 7, 2019

Pectobacterium polaris sp. nov., isolated from potato (Solanum tuberosum).

The genus Pectobacterium, which belongs to the bacterial family Enterobacteriaceae, contains numerous species that cause soft rot diseases in a wide range of plants. The species Pectobacterium carotovorum is highly heterogeneous, indicating a need for re-evaluation and a better classification of the species. PacBio was used for sequencing of two soft-rot-causing bacterial strains (NIBIO1006T and NIBIO1392), initially identified as P. carotovorumstrains by fatty acid analysis and sequencing of three housekeeping genes (dnaX, icdA and mdh). Their taxonomic relationship to other Pectobacterium species was determined and the distance from any described species within the genus Pectobacterium was less than 94?% average nucleotide identity (ANI). Based on ANI, phylogenetic data and genome-to-genome distance, strains NIBIO1006T, NIBIO1392 and NCPPB3395 are suggested to represent a novel species of the genus Pectobacterium, for which the name Pectobacterium polaris sp. nov. is proposed. The type strain is NIBIO1006T (=DSM 105255T=NCPPB 4611T).

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July 7, 2019

Complete genome sequence of Lactobacillus plantarum JBE245 isolated from Meju

Lactobacillus plantarum is widely found in fermented foods and has various phenotypic and genetic characteristics to adapt to the environment. Here we report the complete annotated genome sequence of the L. plantarum strain JBE245 (= KCCM43243) isolated for malolactic fermentation of apple juice. The genome comprises a single circular 3,262,611 bp chromosome with 2907 coding regions, 45 pseudogenes, and 91 RNA genes. The genome contains 4 malate dehydrogenase genes, 3 malate permease genes and various types of plantaricin-synthesizing genes. These genetic traits meet the selection criteria of the strains that should prevent the spoilage of apple juice during fermentation and efficiently convert malate to lactic acid.

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July 7, 2019

Letting go: bacterial genome reduction solves the dilemma of adapting to predation mortality in a substrate-restricted environment.

Resource limitation and predation mortality are major determinants of microbial population dynamics, and optimization for either aspect is considered to imply a trade-off with respect to the other. Adaptation to these selective factors may, moreover, lead to disadvantages at rich growth conditions. We present an example of a concomitant evolutionary optimization to both, substrate limitation and predation in an aggregate-forming freshwater bacterial isolate, and we elucidate an underlying genomic mechanism. Bacteria were propagated in serial batch culture in a nutrient-restricted environment either with or without a bacterivorous flagellate. Strains isolated after 26 growth cycles of the predator-prey co-cultures formed as much total biomass as the ancestor at ancestral growth conditions, albeit largely reallocated to cell aggregates. A ~273?kbp genome fragment was lost in three strains that had independently evolved with predators. These strains had significantly higher growth yield on substrate-restricted media than others that were isolated from the same treatment before the excision event. Under predation pressure, the isolates with the deletion outcompeted both, the ancestor and the strains evolved without predators even at rich growth conditions. At the same time, genome reduction led to a growth disadvantage in the presence of benzoate due to the loss of the respective degradation pathway, suggesting that niche constriction might be the price for the bidirectional optimization.

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July 7, 2019

Complete genome sequence of Spirosoma montaniterrae DY10 T isolated from gamma-ray irradiated soil

A Gram-negative, yellow-pigmented, long-rod shaped bacterium Spirosoma montaniterrae DY10T was isolated from a soil sample collected at Mt. Deogyusan, Jeonbuk Province, Republic of Korea. Cells showed extreme gamma radiation resistance with the D10 value of 12 KGy. The complete genome sequence of strain DY10T is consist of a circular chromosome (5,797,678 bp) encoding 5,116 genes, 9 rRNA genes and 39 tRNA genes. The genomic features contain the key enzymes for gamma and UVC radiation.

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