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July 7, 2019

Genomic reconnaissance of clinical isolates of emerging human pathogen Mycobacterium abscessus reveals high evolutionary potential.

Mycobacterium abscessus (Ma) is an emerging human pathogen that causes both soft tissue infections and systemic disease. We present the first comparative whole-genome study of Ma strains isolated from patients of wide geographical origin. We found a high proportion of accessory strain-specific genes indicating an open, non-conservative pan-genome structure, and clear evidence of rapid phage-mediated evolution. Although we found fewer virulence factors in Ma compared to M. tuberculosis, our data indicated that Ma evolves rapidly and therefore should be monitored closely for the acquisition of more pathogenic traits. This comparative study provides a better understanding of Ma and forms the basis for future functional work on this important pathogen.


July 7, 2019

Molecular and biological characterization of a new isolate of guinea pig cytomegalovirus.

Development of a vaccine against congenital infection with human cytomegalovirus is complicated by the issue of re-infection, with subsequent vertical transmission, in women with pre-conception immunity to the virus. The study of experimental therapeutic prevention of re-infection would ideally be undertaken in a small animal model, such as the guinea pig cytomegalovirus (GPCMV) model, prior to human clinical trials. However, the ability to model re-infection in the GPCMV model has been limited by availability of only one strain of virus, the 22122 strain, isolated in 1957. In this report, we describe the isolation of a new GPCMV strain, the CIDMTR strain. This strain demonstrated morphological characteristics of a typical Herpesvirinae by electron microscopy. Illumina and PacBio sequencing demonstrated a genome of 232,778 nt. Novel open reading frames ORFs not found in reference strain 22122 included an additional MHC Class I homolog near the right genome terminus. The CIDMTR strain was capable of dissemination in immune compromised guinea pigs, and was found to be capable of congenital transmission in GPCMV-immune dams previously infected with salivary gland-adapted strain 22122 virus. The availability of a new GPCMV strain should facilitate study of re-infection in this small animal model.


July 7, 2019

Genomic insights into the taxonomic status of the three subspecies of Bacillus subtilis.

Bacillus subtilis contains three subspecies, i.e., subspecies subtilis, spizizenii, and inaquosorum. As these subspecies are phenotypically indistinguishable, their differentiation has relied on phylogenetic analysis of multiple protein-coding gene sequences. B. subtilis subsp. inaquosorum is a recently proposed taxon that encompasses strain KCTC 13429(T) and related strains, which were previously classified as members of subspecies spizizenii. However, DNA-DNA hybridization (DDH) values among the three subspecies raised a question as to their independence. Thus, we evaluated the taxonomic status of subspecies inaquosorum using genome-based comparative analysis. In contrast to the previous experimental values of DDH, the inter-genomic relatedness inferred by average nucleotide identity (ANI) values indicated that subspecies inaquosorum and spizizenii were sufficiently different from subspecies subtilis and hence raised the possibility that the former two could be classified as separate species from B. subtilis. The genome-based tree also supported the separation of the two subspecies from B. subtilis. The exclusive presence of a subtilin synthesis system in subspecies spizizenii was a remarkable genetic characteristic that could even distinguish subspecies spizizenii from subspecies inaquosorum in addition to the low ANI values (<95%). Conclusively, the genome-based data obtained in this study demonstrated that subspecies inaquosorum and spizizenii are clearly distinguished from subspecies subtilis, and raises the possibility that these two subspecies could be classified as separate species from B. subtilis. In addition, the low ANI values between subspecies inaquosorum and spizizenii and the exclusive presence of subtilin synthesis genes in subspecies spizizenii also suggest circumscription of these two subspecies at the species level. Copyright © 2013 Elsevier GmbH. All rights reserved.


July 7, 2019

Draft genome sequence of Kluyveromyces marxianus strain DMB1, isolated from sugarcane bagasse hydrolysate.

We determined the genome sequence of a thermotolerant yeast, Kluyveromyces marxianus strain DMB1, isolated from sugarcane bagasse hydrolysate, and the sequence provides further insights into the genomic differences between this strain and other reported K. marxianus strains. The genome described here is composed of 11,165,408 bases and has 4,943 protein-coding genes. Copyright © 2014 Suzuki et al.


July 7, 2019

Complete closed genome sequences of three Bibersteinia trehalosi nasopharyngeal isolates from cattle with shipping fever.

Bibersteinia trehalosi is a respiratory pathogen affecting cattle and related ruminants worldwide. B. trehalosi is closely related to Mannheimia haemolytica and is often associated with bovine respiratory disease complex (BRDC), a polymicrobial multifactorial disease. We present three complete closed genome sequences of this species generated using an automated assembly pipeline.


July 7, 2019

Draft genome sequence of Kitasatospora cheerisanensis KCTC 2395, which produces plecomacrolide against phytopathogenic fungi.

Kitasatospora cheerisanensis KCTC 2395, which produces antifungal metabolites with bafilomycin derivatives, including bafilomycin C1-amide, was isolated from a soil sample at Mt. Jiri, South Korea. Here, we report its draft genome sequence, which contains 8.04 Mb with 73.6% G+C content and 7,810 protein-coding genes. Copyright © 2014 Hwang et al.


July 7, 2019

Strain Kaplan of pseudorabies virus genome sequenced by PacBio single-molecule real-time sequencing technology.

Pseudorabies virus (PRV) is a neurotropic herpesvirus that causes Aujeszky’s disease in pigs. PRV strains are widely used as transsynaptic tracers for mapping neural circuits. We present here the complete and fully annotated genome sequence of strain Kaplan of PRV, determined by Pacific Biosciences RSII long-read sequencing technology. Copyright © 2014 Tombácz et al.


July 7, 2019

The oxygen-independent metabolism of cyclic monoterpenes in Castellaniella defragrans 65Phen.

The facultatively anaerobic betaproteobacterium Castellaniella defragrans 65Phen utilizes acyclic, monocyclic and bicyclic monoterpenes as sole carbon source under oxic as well as anoxic conditions. A biotransformation pathway of the acyclic ß-myrcene required linalool dehydratase-isomerase as initial enzyme acting on the hydrocarbon. An in-frame deletion mutant did not use myrcene, but was able to grow on monocyclic monoterpenes. The genome sequence and a comparative proteome analysis together with a random transposon mutagenesis were conducted to identify genes involved in the monocyclic monoterpene metabolism. Metabolites accumulating in cultures of transposon and in-frame deletion mutants disclosed the degradation pathway.Castellaniella defragrans 65Phen oxidizes the monocyclic monoterpene limonene at the primary methyl group forming perillyl alcohol. The genome of 3.95 Mb contained a 70 kb genome island coding for over 50 proteins involved in the monoterpene metabolism. This island showed higher homology to genes of another monoterpene-mineralizing betaproteobacterium, Thauera terpenica 58EuT, than to genomes of the family Alcaligenaceae, which harbors the genus Castellaniella. A collection of 72 transposon mutants unable to grow on limonene contained 17 inactivated genes, with 46 mutants located in the two genes ctmAB (cyclic terpene metabolism). CtmA and ctmB were annotated as FAD-dependent oxidoreductases and clustered together with ctmE, a 2Fe-2S ferredoxin gene, and ctmF, coding for a NADH:ferredoxin oxidoreductase. Transposon mutants of ctmA, B or E did not grow aerobically or anaerobically on limonene, but on perillyl alcohol. The next steps in the pathway are catalyzed by the geraniol dehydrogenase GeoA and the geranial dehydrogenase GeoB, yielding perillic acid. Two transposon mutants had inactivated genes of the monoterpene ring cleavage (mrc) pathway. 2-Methylcitrate synthase and 2-methylcitrate dehydratase were also essential for the monoterpene metabolism but not for growth on acetate.The genome of Castellaniella defragrans 65Phen is related to other genomes of Alcaligenaceae, but contains a genomic island with genes of the monoterpene metabolism. Castellaniella defragrans 65Phen degrades limonene via a limonene dehydrogenase and the oxidation of perillyl alcohol. The initial oxidation at the primary methyl group is independent of molecular oxygen.


July 7, 2019

Improved draft genome sequence of Clostridium pasteurianum strain ATCC 6013 (DSM 525) using a hybrid next-generation sequencing approach.

We present an improved draft genome sequence for Clostridium pasteurianum strain ATCC 6013 (DSM 525), the type strain of the species and an important solventogenic bacterium with industrial potential. Availability of a near-complete genome sequence will enable strain engineering of this promising bacterium. Copyright © 2014 Pyne et al.


July 7, 2019

Compact genome of the Antarctic midge is likely an adaptation to an extreme environment.

The midge, Belgica antarctica, is the only insect endemic to Antarctica, and thus it offers a powerful model for probing responses to extreme temperatures, freeze tolerance, dehydration, osmotic stress, ultraviolet radiation and other forms of environmental stress. Here we present the first genome assembly of an extremophile, the first dipteran in the family Chironomidae, and the first Antarctic eukaryote to be sequenced. At 99 megabases, B. antarctica has the smallest insect genome sequenced thus far. Although it has a similar number of genes as other Diptera, the midge genome has very low repeat density and a reduction in intron length. Environmental extremes appear to constrain genome architecture, not gene content. The few transposable elements present are mainly ancient, inactive retroelements. An abundance of genes associated with development, regulation of metabolism and responses to external stimuli may reflect adaptations for surviving in this harsh environment.


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