The common long-arm octopus (Octopus minor) is found in mudflats of subtidal zones and faces numerous environmental challenges. The ability to adapt its morphology and behavioral repertoire to diverse environmental conditions makes the species a promising model for understanding genomic adaptation and evolution in cephalopods.The final genome assembly of O. minor is 5.09 Gb, with a contig N50 size of 197 kb and longest size of 3.027 Mb, from a total of 419 Gb raw reads generated using the Pacific Biosciences RS II platform. We identified 30,010 genes; 44.43% of the genome is composed of repeat elements. The genome-wide phylogenetic tree indicated the divergence time between O. minor and Octopus bimaculoides was estimated to be 43 million years ago based on single-copy orthologous genes. In total, 178 gene families are expanded in O. minor in the 14 bilaterian species.We found that the O. minor genome was larger than that of closely related O. bimaculoides, and this difference could be explained by enlarged introns and recently diversified transposable elements. The high-quality O. minor genome assembly provides a valuable resource for understanding octopus genome evolution and the molecular basis of adaptations to mudflats.
Metagenomic SMRT sequencing-based exploration of novel lignocellulose-degrading capability in wood detritus from Torreya nucifera in Bija forest on Jeju Island.
Lignocellulose, mostly composed of cellulose, hemicellulose and lignin generated through secondary growth of woody plant, is considered as promising resources for bio-fuel. In order to use lignocellulose as a biofuel, the biodegradation besides high-cost chemical treatments were applied, but its knowledge on decomposition of lignocellulose occurring in a natural environment were insufficient. We analyzed 16S rRNA gene and metagenome to understand how the lignocellulose are decomposed naturally in decayed Torreya nucifera (L) of Bija forest (Bijarim) in Gotjawal, an ecologically distinct environment. A total of 464,360 reads were obtained from 16S rRNA gene sequencing, representing diverse phyla; Proteobacteria (51%), Bacteroidetes (11%) and Actinobacteria (10%). The metagenome analysis using Single Molecules Real-Time Sequencing revealed that the assembled contigs determined by originated from Proteobacteria (58%) and Actinobacteria (10.3%). Carbohydrate Active enZYmes (CAZy) and Protein families (Pfam) based analysis showed that Proteobacteria was involved in degrading whole lignocellulose and Actinobacteria played a role only in a part of hemicellulose degradation. Combining these results, it suggested that Proteobacteria and Actinobacteria had selective biodegradation potential for different lignocellulose substrate. Thus, it is considered that understanding of the systemic microbial degradation pathways may be a useful strategy for recycle of lignocellulosic biomass and the microbial enzymes in Bija forest can be useful natural resources in industrial processes.
Whole genome sequencing of “Faecalibaculum rodentium” ALO17, isolated from C57BL/6J laboratory mouse feces.
Intestinal microorganisms affect host physiology, including ageing. Given the difficulty in controlling for human studies of the gut microbiome, mouse models provide an alternative avenue to study such relationships. In this study, we report on the complete genome of “Faecalibaculum rodentium” ALO17, a bacterium that was isolated from the faeces of a 9-month-old female C57BL/6J mouse. This strain will be utilized in future in vivo studies detailing the relationships between the gut microbiome and ageing.The whole genome sequence of “F. rodentium” ALO17 was obtained using single-molecule, real-time (SMRT) technique on a PacBio instrument. The assembled genome consisted of 2,542,486 base pairs of double-stranded DNA with a GC content of 54.0 % and no plasmids. The genome was predicted to contain 2794 open reading frames, 55 tRNA genes, and 38 rRNA genes. The 16S rRNA gene of ALO17 was 86.9 % similar to that of Allobaculum stercoricanis DSM 13633(T), and the average overall nucleotide identity between strains ALO17 and DSM 13633(T) was 66.8 %. After confirming the phylogenetic relationship between “F. rodentium” ALO17 and A. stercoricanis DSM 13633(T), their whole genome sequences were compared, revealing that “F. rodentium” ALO17 contains more fermentation-related genes than A. stercoricanis DSM 13633(T). Furthermore, “F. rodentium” ALO17 produces higher levels of lactic acid than A. stercoricanis DSM 13633(T) as determined by high-performance liquid chromatography.The availability of the “F. rodentium” ALO17 whole genome sequence will enhance studies concerning the gut microbiota and host physiology, especially when investigating the molecular relationships between gut microbiota and ageing.
Complete genome of streamlined marine actinobacterium Pontimonas salivibrio strain CL-TW6T adapted to coastal planktonic lifestyle.
Pontimonas salivibrio strain CL-TW6T (=KCCM 90105?=?JCM18206) was characterized as the type strain of a new genus within the Actinobacterial family Microbacteriaceae. It was isolated from a coastal marine environment in which members of Microbactericeae have not been previously characterized.The genome of P. salivibrio CL-TW6T was a single chromosome of 1,760,810 bp. Genomes of this small size are typically found in bacteria growing slowly in oligotrophic zones and said to be streamlined. Phylogenetic analysis showed it to represent a lineage originating in the Microbacteriaceae radiation occurring before the snowball Earth glaciations, and to have a closer relationship with some streamlined bacteria known through metagenomic data. Several genomic characteristics typical of streamlined bacteria are found: %G?+?C is lower than non-streamlined members of the phylum; there are a minimal number of rRNA and tRNA genes, fewer paralogs in most gene families, and only two sigma factors; there is a noticeable absence of some nonessential metabolic pathways, including polyketide synthesis and catabolism of some amino acids. There was no indication of any phage genes or plasmids, however, a system of active insertion elements was present. P. salivibrio appears to be unusual in having polyrhamnose-based cell wall oligosaccharides instead of mycolic acid or teichoic acid-based oligosaccharides. Oddly, it conducts sulfate assimilation apparently for sulfating cell wall components, but not for synthesizing amino acids. One gene family it has more of, rather than fewer of, are toxin/antitoxin systems, which are thought to down-regulate growth during nutrient deprivation or other stressful conditions.Because of the relatively small number of paralogs and its relationship to the heavily characterized Mycobacterium tuberculosis, we were able to heavily annotate the genome of P. salivibrio CL-TW6T. Its streamlined status and relationship to streamlined metagenomic constructs makes it an important reference genome for study of the streamlining concept. The final evolutionary trajectory of CL-TW6 T was to adapt to growth in a non-oligotrophic coastal zone. To understand that adaptive process, we give a thorough accounting of gene content, contrasting with both oligotrophic streamlined bacteria and large genome bacteria, and distinguishing between genes derived by vertical and horizontal descent.
Next-generation sequencing has become the most widely used sequencing technology in genomics research, but it has inherent drawbacks when dealing with high-GC content genomes. Recently, single-molecule real-time sequencing technology (SMRT) was introduced as a third-generation sequencing strategy to compensate for this drawback. Here, we report that the unbiased and longer read length of SMRT sequencing markedly improved genome assembly with high GC content via gap filling and repeat resolution.
The genome sequence of the Antarctic bullhead notothen reveals evolutionary adaptations to a cold environment.
BackgroundAntarctic fish have adapted to the freezing waters of the Southern Ocean. Representative adaptations to this harsh environment include a constitutive heat shock response and the evolution of an antifreeze protein in the blood. Despite their adaptations to the cold, genome-wide studies have not yet been performed on these fish due to the lack of a sequenced genome. Notothenia coriiceps, the Antarctic bullhead notothen, is an endemic teleost fish with a circumpolar distribution and makes a good model to understand the genomic adaptations to constant sub-zero temperatures.ResultsWe provide the draft genome sequence and annotation for N. coriiceps. Comparative genome-wide analysis with other fish genomes shows that mitochondrial proteins and hemoglobin evolved rapidly. Transcriptome analysis of thermal stress responses find alternative response mechanisms for evolution strategies in a cold environment. Loss of the phosphorylation-dependent sumoylation motif in heat shock factor 1 suggests that the heat shock response evolved into a simple and rapid phosphorylation-independent regulatory mechanism. Rapidly evolved hemoglobin and the induction of a heat shock response in the blood may support the efficient supply of oxygen to cold-adapted mitochondria.ConclusionsOur data and analysis suggest that evolutionary strategies in efficient aerobic cellular respiration are controlled by hemoglobin and mitochondrial proteins, which may be important for the adaptation of Antarctic fish to their environment. The use of genome data from the Antarctic endemic fish provides an invaluable resource providing evidence of evolutionary adaptation and can be applied to other studies of Antarctic fish.
Geographical structure of endosymbiotic bacteria hosted by Bathymodiolus mussels at eastern Pacific hydrothermal vents.
Chemolithoautotrophic primary production sustains dense invertebrate communities at deep-sea hydrothermal vents and hydrocarbon seeps. Symbiotic bacteria that oxidize dissolved sulfur, methane, and hydrogen gases nourish bathymodiolin mussels that thrive in these environments worldwide. The mussel symbionts are newly acquired in each generation via infection by free-living forms. This study examined geographical subdivision of the thiotrophic endosymbionts hosted by Bathymodiolus mussels living along the eastern Pacific hydrothermal vents. High-throughput sequencing data of 16S ribosomal RNA encoding gene and fragments of six protein-coding genes of symbionts were examined in the samples collected from nine vent localities at the East Pacific Rise, Galápagos Rift, and Pacific-Antarctic Ridge.Both of the parapatric sister-species, B. thermophilus and B. antarcticus, hosted the same numerically dominant phylotype of thiotrophic Gammaproteobacteria. However, sequences from six protein-coding genes revealed highly divergent symbiont lineages living north and south of the Easter Microplate and hosted by these two Bathymodiolus mussel species. High heterogeneity of symbiont haplotypes among host individuals sampled from the same location suggested that stochasticity associated with initial infections was amplified as symbionts proliferated within the host individuals. The mussel species presently contact one another and hybridize along the Easter Microplate, but the northern and southern symbionts appear to be completely isolated. Vicariance associated with orogeny of the Easter Microplate region, 2.5-5.3 million years ago, may have initiated isolation of the symbiont and host populations. Estimates of synonymous substitution rates for the protein-coding bacterial genes examined in this study were 0.77-1.62%/nucleotide/million years.Our present study reports the most comprehensive population genetic analyses of the chemosynthetic endosymbiotic bacteria based on high-throughput genetic data and extensive geographical sampling to date, and demonstrates the role of the geographical features, the Easter Microplate and geographical distance, in the intraspecific divergence of this bacterial species along the mid-ocean ridge axes in the eastern Pacific. Altogether, our results provide insights into extrinsic and intrinsic factors affecting the dispersal and evolution of chemosynthetic symbiotic partners in the hydrothermal vents along the eastern Pacific Ocean.
Complete genome sequence of Stenotrophomonas sp. KCTC 12332, a biotechnological potential bacterium.
Hydroxy fatty acids are used in various industries due to their availability, and in particular, Stenotrophomonas sp. has been regarded as a potential candidate for biotechnological applications, including biotransformation that hydrate unsaturated fatty acids into their derivatives. Here we complete the genome sequence of Stenotrophomonas sp. KCTC 12332 which has a size of 4,541,594bp (G+C content of 63.83%) with 3790 coding DNA sequences (CDSs), 67 tRNA and 3 rRNA operons. The genome contains gene encoding oleate hydratase that can convert oleic acid into 10-hydroxyoctadecanoic acid. Copyright © 2017 Elsevier B.V. All rights reserved.
Shewanella japonica KCTC 22435Tis a facultatively anaerobic, Gram-negative, mesophilic, rod-shaped bacterium isolated from sea water at the Pacific Institute of Bio-organic Chemistry of the Marine Experimental Station, Troitza Bay, Gulf of Peter the Great, Russia. Here, we report the complete genome of S. japonica KCTC 22435T, which consists of 4,975,677bp (G+C content of 40.80%) with a single chromosome, 4036 protein-coding genes, 97 tRNAs and 8 rRNA operons. Genes detected in the genome reveal that the strain possesses a type II secretion system, cytochrome c family proteins with various numbers of heme-binding motifs, and metabolic pathways for utilizing diverse carbon sources, supporting the potential of KCTC 22435Tto generate electricity in salinity culture conditions. Copyright © 2017 Elsevier B.V. All rights reserved.
Complete genome sequence of Pseudomonas antarctica PAMC 27494, a bacteriocin-producing psychrophile isolated from Antarctica.
Antimicrobial-producing, cold-adapted microorganisms have great potential for biotechnological applications in food, pharmaceutical, and cosmetic industries. Pseudomonas antarctica PAMC 27494, a psychrophile exhibiting antimicrobial activity, was isolated from an Antarctic freshwater sample. Here we report the complete genome of P. antarctica PAMC 27494. The strain contains a gene cluster encoding microcin B which inhibits DNA regulations by targeting the DNA gyrase. PAMC 27494 may produce R-type pyocins and also contains a complete set of proteins for the biosynthesis of adenosylcobalamin and possibly induces plant growth by supplying pyrroloquinoline quionone molecules. Copyright © 2017 Elsevier B.V. All rights reserved.
Leuconostoc garlicum KCCM 43211 isolated from traditional Korean fermented food is an intensive producer of exopolysaccharide (EPS). Here we report the first complete genome sequence of L. garlicum KCCM 43211. The genome sequence displayed that this strain contains genes involved in production of EPS possibly composed of glucose monomers. An uncharacterized EPS from the L. garlicum KCCM 43211 strains was also produced during fermentation in the sucrose medium. The MALDI-TOF results displayed the typical mass spectrometry pattern of dextran. This uncharacterized EPS may have use in commercial prebiotics, food additives, and medical purposes. The complete genome sequence of L. garlicum KCCM 43211 will provide valuable information for strain engineering based on the genetic information. Copyright © 2017 Elsevier B.V. All rights reserved.
Complete genome sequence of a psychrotolerant denitrifying bacterium, Janthinobacterium svalbardensis PAMC 27463.
We report here the complete genome sequence of Janthinobacterium svalbardensis PAMC 27463 isolated from a freshwater lake on Barton Peninsula on King George Island, Antarctica. The genome consists of a chromosome with 6,274,078 bp which contains 5,585 genes, including 121 RNA genes. Copyright © 2017 Cho et al.
Complete genome sequence of Hymenobacter sp. strain PAMC26554, an ionizing radiation-resistant bacterium isolated from an Antarctic lichen.
A Gram-negative, rod-shaped, red-pink in color, and UV radiation-resistant bacterium Hymenobacter sp. strain PAMC26554 was isolated from Usnea sp., an Antarctic lichen, and belongs to the class of Cytophagia and the phylum of Bacteroidetes. The complete genome of Hymenobacter sp. PAMC26554 consists of one chromosome (5,244,843bp) with two plasmids (199,990bp and 6421bp). The genomic sequence indicates that Hymenobacter sp. strain PAMC26554 possesses several genes involved in the nucleotide excision repair pathway that protects damaged DNA. This complete genome information will help us to understand its adaptation and novel survival strategy in the Antarctic extreme cold environment. Copyright © 2016 Elsevier B.V. All rights reserved.
Complete genome sequence of the xylan-degrading Mucilaginibacter sp. strain PAMC26640 isolated from an Arctic lichen.
Mucilaginibacter sp. PAMC26640 is a xylan-degrading bacterium isolated from the Arctic lichen Stereocaulon sp. Here, we present the first complete genome sequence of Mucilaginibacter sp. strain PAMC26640, which contains several genes involved in xylan utilization. This genome information provides new insights into the genetic basis of its physiology and further analysis of key metabolic genes related to the xylan degradation pathway. Copyright © 2016. Published by Elsevier B.V.
Complete genome sequence of Frondihabitans sp. strain PAMC28766, a novel carotenoid-producing and radiation-resistant strain isolated from an Antarctic lichen.
Here, we report the first complete genome sequence of Frondihabitans sp. strain PAMC28766, which was found to consist of three plasmids, one chromosome (4,345,897bp), and a series of genes involved in carotenoid biosynthesis and nucleotide excision repair. An analysis of the Frondihabitans sp. PAMC28766 genome will improve our understanding of the carotenoid biosynthesis pathway. Furthermore, the sequence data will provide novel insight into UV radiation-resistance in extremely cold environments. Copyright © 2016 Elsevier B.V. All rights reserved.