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July 7, 2019

Complete genome sequences of Clostridium perfringens Del1 strain isolated from chickens affected by necrotic enteritis.

Clostridium perfringens is ubiquitous in nature. It is a normal inhabitant in the intestinal tract of animals and humans. As the primary etiological agent of gas gangrene, necrosis and bacteremia, C. perfringens causes food poisoning, necrotic enteritis (NE), and even death. Epidemiology research has indicated that the increasing incidence of NE in poultry is associated with the withdrawal of in-feed antibiotic growth promoters in poultry production in response to government regulations. The recent omics studies have indicated that bacterial virulence is typically linked to highly efficient conjugative transfer of toxins, or plasmids carrying antibiotic-resistance traits. Currently, there is limited information on understanding of host-pathogen interaction in NE caused by virulent strains of C. perfringens. Elucidating such pathogenesis has practical impacts on fighting infectious diseases through adopting strategies of prophylactic or therapeutic interventions. In this report, we sequenced and analyzed the genome of C. perfringens Del1 strain using the hybrid of PacBio and Illumina sequencing technologies.Sequence analysis indicated that Del1 strain comprised a single circular chromosome with a complete 3,559,163 bp and 4 plasmids: pDel1_1 (82,596 bp), pDel1_2 (69,827 bp), pDel1_3 (49,582 bp), and pDel1_4 (49,728 bp). The genome had 3361 predicted coding DNA sequences, harbored numerous genes for pathogenesis and virulence factors, including 6 for antibiotic and antimicrobial resistance, and 3 phage-encoded genes. Phylogenetic analysis revealed that Del1 strain had similar genome and plasmid sequences to the CP4 strain.Complete chromosomal and plasmid sequences of Del1 strain are presented in this report. Since Del1 was isolated from a field disease outbreak, this strain is a good source to identify virulent genes that cause many damaging effects of Clostridial infections in chicken gut. Genome sequencing of the chicken pathogenic isolates from commercial farms provides valuable insights into the molecular pathogenesis of C. perfringens as a gastrointestinal pathogen in food animals. The detailed information on gene sequencing of this important field strain will benefit the development of novel vaccines specific for C. perfringens-induced NE in chickens.


July 7, 2019

Complete circularized genome sequences of four strains of Elizabethkingia anophelis, including two novel strains isolated from wild-caught Anopheles sinensis.

We provide complete circularized genome sequences of two mosquito-derived Elizabethkingia anophelis strains with draft sequences currently in the public domain (R26 and Ag1), and two novel E. anophelis strains derived from a different mosquito species, Anopheles sinensis (AR4-6 and AR6-8). The genetic similarity of all four mosquito-derived strains is remarkable.


July 7, 2019

Complete genome sequence of Acetobacter pomorum Oregon-R-modENCODE strain BDGP5, an acetic acid bacterium found in the Drosophila melanogaster gut.

Acetobacter pomorum Oregon-R-modENCODE strain BDGP5 was isolated from Drosophila melanogaster for functional host-microbe interaction studies. The complete genome is composed of a single chromosomal circle of 2,848,089 bp, with a G+C content of 53% and three plasmids of 131,455 bp, 19,216 bp, and 9,160 bp. Copyright © 2017 Wan et al.


July 7, 2019

Comparative genomic analysis of two clonally related multidrug resistant Mycobacterium tuberculosis by Single Molecule Real Time Sequencing.

Background: Multidrug-resistant tuberculosis (MDR-TB) is posing a major threat to global TB control. In this study, we focused on two consecutive MDR-TB isolated from the same patient before and after the initiation of anti-TB treatment. To better understand the genomic characteristics of MDR-TB, Single Molecule Real-Time (SMRT) Sequencing and comparative genomic analyses was performed to identify mutations that contributed to the stepwise development of drug resistance and growth fitness in MDR-TB underin vivochallenge of anti-TB drugs.Result:Both pre-treatment and post-treatment strain demonstrated concordant phenotypic and genotypic susceptibility profiles toward rifampicin, pyrazinamide, streptomycin, fluoroquinolones, aminoglycosides, cycloserine, ethionamide, and para-aminosalicylic acid. However, although both strains carried identical missense mutations atrpoBS531L,inhAC-15T, andembBM306V, MYCOTB Sensititre assay showed that the post-treatment strain had 16-, 8-, and 4-fold elevation in the minimum inhibitory concentrations (MICs) toward rifabutin, isoniazid, and ethambutol respectively. The results have indicated the presence of additional resistant-related mutations governing the stepwise development of MDR-TB. Further comparative genomic analyses have identified three additional polymorphisms between the clinical isolates. These include a single nucleotide deletion at nucleotide position 360 ofrv0888in pre-treatment strain, and a missense mutation atrv3303c(lpdA)V44I and a 6-bp inframe deletion at codon 67-68 inrv2071c(cobM)in the post-treatment strain. Multiple sequence alignment showed that these mutations were occurring at highly conserved regions among pathogenic mycobacteria. Using structural-based and sequence-based algorithms, we further predicted that the mutations potentially have deleterious effect on protein function.Conclusion:This is the first study that compared the full genomes of two clonally-related MDR-TB clinical isolates during the course of anti-TB treatment. Our work has demonstrated the robustness of SMRT Sequencing in identifying mutations among MDR-TB clinical isolates. Comparative genome analysis also suggested novel mutations atrv0888, lpdA, andcobMthat might explain the difference in antibiotic resistance and growth pattern between the two MDR-TB strains.


July 7, 2019

Complete genome sequence of Bacillus altitudinis P-10, a potential bioprotectant against Xanthomonas oryzae pv. oryzae, isolated from rice rhizosphere in Java, Indonesia.

Bacillus altitudinis P-10 was isolated from the rhizosphere of rice grown in an organic rice field and provides strong antagonism against the bacterial blight caused by Xanthomonas oryzae pv. oryzae in rice. Herein, we provide the complete genome sequence and a possible explanation of the antibiotic function of the P-10 strain.


July 7, 2019

High-quality draft genome sequence of Streptomyces agglomeratus 5-1-8 with strong anti-MRSA ability, isolated from the frozen soil of Tibet in China

Streptomyces agglomeratus 5-1-8 with strong anti methicillin-resistant Staphylococcus aureus (MRSA) ability, isolated from the frozen soil of Tibet in China, has a strong ability to kill the multi-drugs-resistant MRSA. To identify the second-ary metabolism ability of this strain, we describe here the phenotypic characteristics of this strain, along with its high-quality draft genome sequence, its annotation, and analysis. The 7.1M draft genome encodes 6,284 putative open reading frames (ORFs), of which 4,416 ORFs were assigned with clusters of orthologous genes (COG) categories. Also, 65 tRNA genes and 24 rRNA operons were identified. The genome contains 12 gene clusters involved in antibiotics production and 1 gene cluster involved in anticancer-compounds production; 4 gene clusters belong to polyketides and nonribosomal peptides, 1 gene cluster belong to the butyrolactone, 4 gene clusters belong to the bacteriocin or lantipeptide, and 3 gene clusters belong to the others. This genome-sequence data will facilitate efforts to probe the potential of new antibiotics to kill multi-drugs-resistant MRSA.


July 7, 2019

Sex-specific influences of mtDNA mitotype and diet on mitochondrial functions and physiological traits in Drosophila melanogaster.

Here we determine the sex-specific influence of mtDNA type (mitotype) and diet on mitochondrial functions and physiology in two Drosophila melanogaster lines. In many species, males and females differ in aspects of their energy production. These sex-specific influences may be caused by differences in evolutionary history and physiological functions. We predicted the influence of mtDNA mutations should be stronger in males than females as a result of the organelle’s maternal mode of inheritance in the majority of metazoans. In contrast, we predicted the influence of diet would be greater in females due to higher metabolic flexibility. We included four diets that differed in their protein: carbohydrate (P:C) ratios as they are the two-major energy-yielding macronutrients in the fly diet. We assayed four mitochondrial function traits (Complex I oxidative phosphorylation, reactive oxygen species production, superoxide dismutase activity, and mtDNA copy number) and four physiological traits (fecundity, longevity, lipid content, and starvation resistance). Traits were assayed at 11 d and 25 d of age. Consistent with predictions we observe that the mitotype influenced males more than females supporting the hypothesis of a sex-specific selective sieve in the mitochondrial genome caused by the maternal inheritance of mitochondria. Also, consistent with predictions, we found that the diet influenced females more than males.


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.


July 7, 2019

The complete mitochondrial genome of Wonwhang (Pyrus pyrifolia)

This is a de novo assembly and annotation of a complete mitochondrial genome from Pyrus pyrifolia in the family Rosaceae. The complete mitochondrial genome of P. pyrifolia was assembled from PacBio RSII P6-C4 sequencing reads. The circular genome was 458,873?bp in length, containing 39 protein-coding genes, 23 tRNA genes and three rRNA genes. The nucleotide composition was A (27.5%), T (27.3%), G (22.6%) and C (22.6%) with GC content of 45.2%. Most of protein-coding genes use the canonical start codon ATG, whereas nad1, cox1, matR and rps4 use ACG, mttB uses ATT, rpl16 and rps19 uses GTG. The stop codon is also common in all mitochondrial genes. The phylogenetic analysis showed that P. pyrifolia was clustered with the Malus of Rosaceae family. Maximum-likelihood analysis suggests a clear relationship of Rosids and Asterids, which support the traditional classification.


July 7, 2019

Evaluation of the impact of ul54 gene-deletion on the global transcription and DNA replication of pseudorabies virus.

Pseudorabies virus (PRV) is an animal alphaherpesvirus with a wide host range. PRV has 67 protein-coding genes and several non-coding RNA molecules, which can be classified into three temporal groups, immediate early, early and late classes. The ul54 gene of PRV and its homolog icp27 of herpes simplex virus have a multitude of functions, including the regulation of viral DNA synthesis and the control of the gene expression. Therefore, abrogation of PRV ul54 function was expected to exert a significant effect on the global transcriptome and on DNA replication. Real-time PCR and real-time RT-PCR platforms were used to investigate these presumed effects. Our analyses revealed a drastic impact of the ul54 mutation on the genome-wide expression of PRV genes, especially on the transcription of the true late genes. A more than two hour delay was observed in the onset of DNA replication, and the amount of synthesized DNA molecules was significantly decreased in comparison to the wild-type virus. Furthermore, in this work, we were able to successfully demonstrate the utility of long-read SMRT sequencing for genotyping of mutant viruses.


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).


July 7, 2019

First Azospirillum genome from aquatic environments: Whole-genome sequence of Azospirillum thiophilum BV-S(T), a novel diazotroph harboring a capacity of sulfur-chemolithotrophy from a sulfide spring.

Azospirillum thiophilum BV-S(T), isolated from a sulfide spring, is a novel nitrogen-fixing bacterium harboring sulfur-lithotrophy. In order to identify genetic characteristics with habitat- and metabolic features contrasting to those from terrestrial Azospirillum species, we present here the genome sequence of a novel species A. thiophilum BV-S(T), with a significance of first genome report in the aquatic Azospirillum species. The genome of strain BV-S(T) is comprised of 7.6Mb chromosome with a GC content of 68.2%. This information will contribute to expand understandings of sulfur-oxidizer microbes that preserve inherencies as a diazotroph, and further it will provide insights into genome plasticity of the genus Azospirillum for niche specific adaptations. Copyright © 2015 Elsevier B.V. All rights reserved.


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