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July 7, 2019  |  

Cupriavidus malaysiensis sp. nov., a novel poly(3-hydroxybutyrate-co-4-hydroxybutyrate) accumulating bacterium isolated from the Malaysian environment.

Bacterial classification on the basis of a polyphasic approach was conducted on three poly(3 hydroxybutyrate-co-4-hydroxybutyrate) [P(3HB-co-4HB)] accumulating bacterial strains that were isolated from samples collected from Malaysian environments; Kulim Lake, Sg. Pinang river and Sg. Manik paddy field. The Gram-negative, rod-shaped, motile, non-sporulating and non-fermenting bacteria were shown to belong to the genus Cupriavidus of the Betaproteobacteria on the basis of their 16S rRNA gene sequence analyses. The sequence similarity value with their near phylogenetic neighbour, Cupriavidus pauculus LMG3413T, was 98.5%. However, the DNA-DNA hybridization values (8-58%) and ribotyping analysis both enabled these strains to be differentiated from related Cupriavidus species with validly published names. The RiboPrint patterns of the three strains also revealed that the strains were genetically related even though they displayed a clonal diversity. The major cellular fatty acids detected in these strains included C15:0 ISO 2OH/C16:1 ?7c, hexadecanoic (16:0) and cis-11-octadecenoic (C18:1 ?7c). Their G+C contents ranged from 68.0  to 68.6 mol%, and their major isoprenoid quinone was Ubiquinone Q-8. Of these three strains, only strain USMAHM13 (= DSM 25816 = KCTC 32390) was discovered to exhibit yellow pigmentation that is characteristic of the carotenoid family. Their assembled genomes also showed that the three strains were not identical in terms of their genome sizes that were 7.82, 7.95 and 8.70 Mb for strains USMAHM13, USMAA1020 and USMAA2-4, respectively, which are slightly larger than that of Cupriavidus necator H16 (7.42 Mb). The average nucleotide identity (ANI) results indicated that the strains were genetically related and the genome pairs belong to the same species. On the basis of the results obtained in this study, the three strains are considered to represent a novel species for which the name Cupriavidus malaysiensis sp. nov. is proposed. The type strain of the species is USMAA1020T (= DSM 19416T = KCTC 32390T).


July 7, 2019  |  

Complete genome sequence of the halophilic methylotrophic methanogen archaeon Methanohalophilus portucalensis strain FDF-1T.

We report here the complete genome sequence (2.08 Mb) of Methanohalophilus portucalensis strain FDF-1T, a halophilic methylotrophic methanogen isolated from the sediment of a saltern in Figeria da Foz, Portugal. The average nucleotide identity and DNA-DNA hybridization analyses show that Methanohalophilus mahii, M. halophilus, and M. portucalensis are three different species within the Methanosarcinaceae family.


July 7, 2019  |  

Complete genome sequence of a new halophilic archaeon, Haloarcula taiwanensis, isolated from a solar saltern in southern Taiwan.

We report here the completion of the genome sequence of a new species of haloarchaea, Haloarcula taiwanensis, isolated in southern Taiwan. The 3,721,706-bp genome consisted of chromosome I (2,966,258 bp, 63.6% GC content), chromosome II (525,233 bp, 59.6% GC content), plasmid pNYT1 (129,893 bp, 55.3% GC content), and plasmid pNYT2 (100,322 bp, 55.7% GC content).


July 7, 2019  |  

Paucibacter aquatile sp. nov. isolated from freshwater of the Nakdong River, Republic of Korea.

A Gram-negative, aerobic, motile, and rod-shaped bacterial strain designated CR182T was isolated from freshwater of the Nakdong River, Republic of Korea. Optimal growth conditions for this novel strain were found to be: 25-30 °C, pH 6.5-8.5, and 3% (w/v) NaCl. Phylogenetic analysis based on 16S rRNA gene sequence indicates that the strain CR182T belongs to type strains of genus Paucibacter. Strain CR182T showed 98.0% 16S rRNA gene sequence similarity with Paucibacter oligotrophus CHU3T and formed a robust phylogenetic clade with this species. The average nucleotide identity value between strain CR182T and P. oligotrophus CHU3T was 78.4% and the genome-to-genome distance was 22.2% on average. The genomic DNA G+C content calculated from the genome sequence was 66.3 mol%. Predominant cellular fatty acids of strain CR182T were summed feature 3 (C16:1 ?7c and/or C16:1 ?6c) (31.2%) and C16:0 (16.0%). Its major respiratory quinine was ubiquinone Q-8. Its polar lipids consisted of diphosphatidylglycerol, phosphatidylethanolamine, and two unidentified phospholipids. Its genomic DNA G+C content was 66.3%. Based on data obtained from this polyphasic taxonomic study, strain CR182T represents a novel species belonging to genus Paucibacter, for which a name of P. aquatile sp. nov. is proposed. The type strain is CR182T (=?KCCM 90284T?=?NBRC 113032T).


July 7, 2019  |  

The complete genome sequence of Colwellia sp. NB097-1 reveals evidence for the potential genetic basis for its adaptation to cold environment

Colwellia sp. NB097-1, isolated from a marine sediment sample from the Bering Sea, is a psychrophilic bacterium whose optimal and maximal growth temperatures were 13 and 25°C, respectively. Here, we present the complete genome of Colwellia sp. NB097-1, which was 4,661,274bp in length with a GC content of 38.5%. The genome provided evidence for the potential genetic basis for its adaptation to a cold environment, such as producing compatible solutes and cold-shock proteins, increasing membrane fluidity and synthesizing glycogen. Some cold-adaptive proteases were also detected in the genome of Colwellia sp. NB097-1. Protease activity analysis further showed that extracellular proteases of Colwellia sp. NB097-1 remained active at low temperatures. The complete genome sequence may be helpful to reveal how this strain survives at low temperature and to find cold-adaptive proteases that may be useful to industry.


July 7, 2019  |  

Complete genome of Halomonas aestuarii Hb3, isolated from tidal flat

Halomonas aestuarii Hb3, a moderately halophilic bacterium belonging to the class Gammaproteobacteria, was isolated from a tidal flat. Herein, we report the complete genome sequence of its strain Hb3. Its size is estimated at 3.54Mbp with a mean G+C content of 67.9%. The genome includes 3238 open reading frames, 65 transfer RNAs, and four ribosomal RNA gene operons. Genes related to the degradation of monoaromatic compounds, detoxification of arsenic, and production of polymers were identified. These features indicate that this strain may be important for ecological and industrial application.


July 7, 2019  |  

Complete genome sequence of the marine Rhodococcus sp. H-CA8f isolated from Comau fjord in Northern Patagonia, Chile

Rhodococcus sp. H-CA8f was isolated from marine sediments obtained from the Comau fjord, located in Northern Chilean Patagonia. Whole-genome sequencing was achieved using PacBio RS II platform, comprising one closed, complete chromosome of 6,19?Mbp with a 62.45% G?+?C content. The chromosome harbours several metabolic pathways providing a wide catabolic potential, where the upper biphenyl route is described. Also, Rhodococcus sp. H-CA8f bears one linear mega-plasmid of 301?Kbp and 62.34% of G?+?C content, where genomic analyses demonstrated that it is constituted mostly by putative ORFs with unknown functions, representing a novel genetic feature. These genetic characteristics provide relevant insights regarding Chilean marine actinobacterial strains.


July 7, 2019  |  

Strategies for high-altitude adaptation revealed from high-quality draft genome of non-violacein producing Janthinobacterium lividum ERGS5:01.

A light pink coloured bacterial strain ERGS5:01 isolated from glacial stream water of Sikkim Himalaya was affiliated to Janthinobacterium lividum based on 16S rRNA gene sequence identity and phylogenetic clustering. Whole genome sequencing was performed for the strain to confirm its taxonomy as it lacked the typical violet pigmentation of the genus and also to decipher its survival strategy at the aquatic ecosystem of high elevation. The PacBio RSII sequencing generated genome of 5,168,928 bp with 4575 protein-coding genes and 118 RNA genes. Whole genome-based multilocus sequence analysis clustering, in silico DDH similarity value of 95.1% and, the ANI value of 99.25% established the identity of the strain ERGS5:01 (MCC 2953) as a non-violacein producing J. lividum. The genome comparisons across genus Janthinobacterium revealed an open pan-genome with the scope of the addition of new orthologous cluster to complete the genomic inventory. The genomic insight provided the genetic basis of freezing and frequent freeze-thaw cycle tolerance and, for industrially important enzymes. Extended insight into the genome provided clues of crucial genes associated with adaptation in the harsh aquatic ecosystem of high altitude.


July 7, 2019  |  

Rhodobacter sp. Rb3, an aerobic anoxygenic phototroph which thrives in the polyextreme ecosystem of the Salar de Huasco, in the Chilean Altiplano.

The Salar de Huasco is an evaporitic basin located in the Chilean Altiplano, which presents extreme environmental conditions for life, i.e. high altitude (3800 m.a.s.l.), negative water balance, a wide salinity range, high daily temperature changes and the occurrence of the highest registered solar radiation on the planet (>?1200 W m-2). This ecosystem is considered as a natural laboratory to understand different adaptations of microorganisms to extreme conditions. Rhodobacter, an anoxygenic aerobic phototrophic bacterial genus, represents one of the most abundant groups reported based on taxonomic diversity surveys in this ecosystem. The bacterial mat isolate Rhodobacter sp. strain Rb3 was used to study adaptation mechanisms to stress-inducing factors potentially explaining its success in a polyextreme ecosystem. We found that the Rhodobacter sp. Rb3 genome was characterized by a high abundance of genes involved in stress tolerance and adaptation strategies, among which DNA repair and oxidative stress were the most conspicuous. Moreover, many other molecular mechanisms associated with oxidative stress, photooxidation and antioxidants; DNA repair and protection; motility, chemotaxis and biofilm synthesis; osmotic stress, metal, metalloid and toxic anions resistance; antimicrobial resistance and multidrug pumps; sporulation; cold shock and heat shock stress; mobile genetic elements and toxin-antitoxin system were detected and identified as potential survival mechanism features in Rhodobacter sp. Rb3. In total, these results reveal a wide set of strategies used by the isolate to adapt and thrive under environmental stress conditions as a model of polyextreme environmental resistome.


July 7, 2019  |  

Complete genome sequence of Microcystis aeruginosa NIES-2481 and common genomic features of group G M. aeruginosa.

Microcystis aeruginosa is a freshwater bloom-forming cyanobacterium that is distributed worldwide. M. aeruginosa can be divided into at least 8 phylogenetic groups (A-G and X) at the intraspecific level. Here, we report the complete genome sequence of M. aeruginosa NIES-2481, which was isolated from Lake Kasumigaura, Japan, and is assigned to group G. The complete genome sequence of M. aeruginosa NIES-2481 comprises a 4.29-Mbp circular chromosome and a 147,539-bp plasmid; the circular chromosome and the plasmid contain 4,332 and 167 protein-coding genes, respectively. Comparative analysis with the complete genome of M. aeruginosa NIES-2549, which belongs to the same group with NIES-2481, showed that the genome size is the smallest level in previously sequenced M. aeruginosa strains, and the genomes do not contain a microcystin biosynthetic gene cluster in common. Synteny analysis revealed only small-scale rearrangements between the two genomes.


July 7, 2019  |  

Complete genome sequence of Loktanella vestfoldensis strain SMR4r, a novel strain isolated from a culture of the chain-forming diatom Skeletonema marinoi.

We report here the genome sequence of Loktanella vestfoldensis strain SMR4r, isolated from the marine diatom Skeletonema marinoi strain RO5AC. Its 3,987,360-bp genome consists of a circular chromosome and two circular plasmids, one of which appears to be shared with an S. marinoi-associated Roseovarius species. Copyright © 2018 Töpel et al.


July 7, 2019  |  

Complete genome sequence of “Thiodictyon syntrophicum” sp. nov. strain Cad16T, a photolithoautotrophic purple sulfur bacterium isolated from the alpine meromictic Lake Cadagno.

Thiodictyon syntrophicum sp. nov. strain Cad16T is a photoautotrophic purple sulfur bacterium belonging to the family of Chromatiaceae in the class of Gammaproteobacteria. The type strain Cad16T was isolated from the chemocline of the alpine meromictic Lake Cadagno in Switzerland. Strain Cad16T represents a key species within this sulfur-driven bacterial ecosystem with respect to carbon fixation. The 7.74-Mbp genome of strain Cad16T has been sequenced and annotated. It encodes 6237 predicted protein sequences and 59 RNA sequences. Phylogenetic comparison based on 16S rRNA revealed that Thiodictyon elegans strain DSM 232T the most closely related species. Genes involved in sulfur oxidation, central carbon metabolism and transmembrane transport were found. Noteworthy, clusters of genes encoding the photosynthetic machinery and pigment biosynthesis are found on the 0.48 Mb plasmid pTs485. We provide a detailed insight into the Cad16T genome and analyze it in the context of the microbial ecosystem of Lake Cadagno.


July 7, 2019  |  

Assembly of a complete genome sequence for Gemmata obscuriglobus reveals a novel prokaryotic rRNA operon gene architecture.

Gemmata obscuriglobus is a Gram-negative bacterium with several intriguing biological features. Here, we present a complete, de novo whole genome assembly for G. obscuriglobus which consists of a single, circular 9 Mb chromosome, with no plasmids detected. The genome was annotated using the NCBI Prokaryotic Genome Annotation pipeline to generate common gene annotations. Analysis of the rRNA genes revealed three interesting features for a bacterium. First, linked G. obscuriglobus rrn operons have a unique gene order, 23S-5S-16S, compared to typical prokaryotic rrn operons (16S-23S-5S). Second, G. obscuriglobus rrn operons can either be linked or unlinked (a 16S gene is in a separate genomic location from a 23S and 5S gene pair). Third, all of the 23S genes (5 in total) have unique polymorphisms. Genome analysis of a different Gemmata species (SH-PL17), revealed a similar 23S-5S-16S gene order in all of its linked rrn operons and the presence of an unlinked operon. Together, our findings show that unique and rare features in Gemmata rrn operons among prokaryotes provide a means to better define the evolutionary relatedness of Gemmata species and the divergence time for different Gemmata species. Additionally, these rrn operon differences provide important insights into the rrn operon architecture of common ancestors of the planctomycetes.


July 7, 2019  |  

Activation of the mismatch-specific endonuclease EndoMS/NucS by the replication clamp is required for high fidelity DNA replication.

The mismatch repair (MMR) system, exemplified by the MutS/MutL proteins, is widespread in Bacteria and Eukarya. However, molecular mechanisms how numerous archaea and bacteria lacking the mutS/mutL genes maintain high replication fidelity and genome stability have remained elusive. EndoMS is a recently discovered hyperthermophilic mismatch-specific endonuclease encoded by nucS in Thermococcales. We deleted the nucS from the actinobacterium Corynebacterium glutamicum and demonstrated a drastic increase of spontaneous transition mutations in the nucS deletion strain. The observed spectra of these mutations were consistent with the enzymatic properties of EndoMS in vitro. The robust mismatch-specific endonuclease activity was detected with the purified C. glutamicum EndoMS protein but only in the presence of the ß-clamp (DnaN). Our biochemical and genetic data suggest that the frequently occurring G/T mismatch is efficiently repaired by the bacterial EndoMS-ß-clamp complex formed via a carboxy-terminal sequence motif of EndoMS proteins. Our study thus has great implications for understanding how the activity of the novel MMR system is coordinated with the replisome and provides new mechanistic insight into genetic diversity and mutational patterns in industrially and clinically (e.g. Mycobacteria) important archaeal and bacterial phyla previously thought to be devoid of the MMR system.


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