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April 21, 2020

In situ enrichment of microbial communities on polarized electrodes deployed in alkaline hot springs

The discovery of the ability of microorganisms to exchange electrons with inert electrodes has triggered new areas in fundamental and applied research. However, the field is currently limited to several known electrochemically active microorganisms enriched and isolated in research laboratories. An alternative strategy is to enrich such microorganisms in their native environment by allowing them to exchange electrons with polarized solid electrodes. The use of this approach is currently limited because of a lack of available tools. We developed a low-cost, battery-operated potentiostat that is capable of controlling the potential of a working electrode and can be deployed and operated remotely, allowing the enrichment of microorganisms on electrodes in their native environment. The device was tested in four alkaline hot springs in Heart Lake Geyser Basin in Yellowstone National Park (with a temperature ranging from 45 ?C to 91 ?C and a relatively constant pH of 8.5–8.7). Microbial community analysis showed a change in microbial community structure after 32 days of polarization. The impact of polarization on microbial community was most substantial on the electrodes that generated the highest cathodic and anodic currents, suggesting a direct impact of polarization on electrode microbial community.


April 21, 2020

Complete genome of Pseudoalteromonas atlantica ECSMB14104, a Gammaproteobacterium inducing mussel settlement

Pseudoalteromonas is widely distributed in the marine environments and the biofilms formed by Pseudoalteromonas promote settlement of many species of invertebrates. Here, we show the complete genome of Pseudoalteromonas atlantica ECSMB14104, which was isolated from biofilms formed in the East China Sea and exhibited inducing activity on the Mytilus coruscus settlement. Complete genome of this strain containsa total of 3325 genes and the GC content of 41.02%. This genomic information is contributed to molecular mechanism of P. atlantica ECSMB14104 regulating mussel settlement.


April 21, 2020

Full-length mRNA sequencing in Saccharina japonica and identification of carbonic anhydrase genes

The carbonic anhydrases (CAs) are a group of enzymes that play an important role in the absorption and transportation of CO2 in Saccharina japonica. They are encoded by a superfamily of genes with seven subtypes that are unrelated in sequence but share conserved function in catalyzing the reversible conversion of CO2 and HCO3-. Here we have characterized the CA members in the transcriptome of S. japonica using Single-molecule real-time (SMRT) sequencing technology. Approximately 9830.4 megabases from 5,028,003 quality subreads were generated, and they were assembled into 326,512 full-length non-chimeric (FLNC) reads, with an average flnc read length of 2181 bp. After removing redundant sequences, 79,010 unique transcripts were obtained of which 38,039 transcripts were successfully annotated. From the full-length transcriptome, we have identified 7 full-length cDNA sequences for CA genes (4 a-CAs, 1 ß-CAs and 2 ?-CAs) and assessed for their potential functions based on phylogenetic analysis. Characterizations of CAs will provide the ground for future studies to determine the involvement of CAs in inorganic carbon absorption and transportation in S. japonica.


April 21, 2020

Genome sequence of Jatropha curcas L., a non-edible biodiesel plant, provides a resource to improve seed-related traits.

Jatropha curcas (physic nut), a non-edible oilseed crop, represents one of the most promising alternative energy sources due to its high seed oil content, rapid growth and adaptability to various environments. We report ~339 Mbp draft whole genome sequence of J. curcas var. Chai Nat using both the PacBio and Illumina sequencing platforms. We identified and categorized differentially expressed genes related to biosynthesis of lipid and toxic compound among four stages of seed development. Triacylglycerol (TAG), the major component of seed storage oil, is mainly synthesized by phospholipid:diacylglycerol acyltransferase in Jatropha, and continuous high expression of homologs of oleosin over seed development contributes to accumulation of high level of oil in kernels by preventing the breakdown of TAG. A physical cluster of genes for diterpenoid biosynthetic enzymes, including casbene synthases highly responsible for a toxic compound, phorbol ester, in seed cake, was syntenically highly conserved between Jatropha and castor bean. Transcriptomic analysis of female and male flowers revealed the up-regulation of a dozen family of TFs in female flower. Additionally, we constructed a robust species tree enabling estimation of divergence times among nine Jatropha species and five commercial crops in Malpighiales order. Our results will help researchers and breeders increase energy efficiency of this important oil seed crop by improving yield and oil content, and eliminating toxic compound in seed cake for animal feed. © 2018 The Authors. Plant Biotechnology Journal published by Society for Experimental Biology and The Association of Applied Biologists and John Wiley & Sons Ltd.


April 21, 2020

Complete genome sequence of the novel agarolytic Catenovulum-like strain CCB-QB4

Members of the genus Catenovulum are recognized for their ability to degrade algal biomass. Here we report the complete genome of Cantenovulum–like strain CCB-QB4, an agarolytic bacterium isolated from the coastal area of Penang, Malaysia. The sequenced genome is composed of a 5,663,044?bp circular chromosome and a 208,085?bp circular plasmid. It contained 4409 protein coding and 83 RNA genes, including 62 tRNAs and 21 rRNAs. The genome of CCB-QB4 contains many agarases, which correlate with the high capacity of the strain to degrade agar. Genome sequencing of CCB-QB4 reveals gene candidates of potential interest in enzymatic industries or applications in the field of polysaccharides degradation.


April 21, 2020

Complete genome sequence of Pseudomonas frederiksbergensis ERDD5:01 revealed genetic bases for survivability at high altitude ecosystem and bioprospection potential.

Pseudomonas frederiksbergensis ERDD5:01 is a psychrotrophic bacteria isolated from the glacial stream flowing from East Rathong glacier in Sikkim Himalaya. The strain showed survivability at high altitude stress conditions like freezing, frequent freeze-thaw cycles, and UV-C radiations. The complete genome of 5,746,824?bp circular chromosome and a plasmid of 371,027?bp was sequenced to understand the genetic basis of its survival strategy. Multiple copies of cold-associated genes encoding cold active chaperons, general stress response, osmotic stress, oxidative stress, membrane/cell wall alteration, carbon storage/starvation and, DNA repair mechanisms supported its survivability at extreme cold and radiations corroborating with the bacterial physiological findings. The molecular cold adaptation analysis in comparison with the genome of 15 mesophilic Pseudomonas species revealed functional insight into the strategies of cold adaptation. The genomic data also revealed the presence of industrially important enzymes.Copyright © 2018 Elsevier Inc. All rights reserved.


April 21, 2020

Complete genome sequence of Paracoccus denitrificans ATCC 19367 and its denitrification characteristics.

Studies show that Paracoccus denitrificans can denitrify nitrogen sources under aerobic conditions. However, the lack of data on its genome sequence has restricted molecular studies and practical applications. In this study, the complete genome of P. denitrificans ATCC 19367 was sequenced and its nitrogen metabolism properties were characterized. The size of the whole genome is 5?242?327 bp, with two chromosomes and one plasmid. The average G + C content is 66.8%, and it contains 5308 protein-coding genes, 54 tRNA genes, and nine rRNA operons. Among the protein-coding genes, 71.35% could be assigned to the Gene Ontology (GO) pathway, 86.66% to the Clusters of Orthologous Groups (COG) pathway, and 50.57% to the Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway. Comparative genome analysis between P. denitrificans ATCC 19367 and P. denitrificans PD1222 revealed that there are 428 genes specific to ATCC 19367 and 4738 core genes. Furthermore, the expression of genes related to denitrification, biofilm formation, and nitrogen metabolism (nar, nir, and nor) by P. denitrificans ATCC 19367 under aerobic conditions was affected by incubation time and shaking speed. This study elucidates the genomic background of P. denitrificans ATCC 19367 and suggests the possibility of controlling nitrogen pollution in the environment by using this bacterium.


April 21, 2020

Complete Genome Sequence of Lactic Acid Bacterium Pediococcus acidilactici Strain ATCC 8042, an Autolytic Anti-bacterial Peptidoglycan Hydrolase Producer

Pediococcus acidilactici is a probiotic bacterium that is industrially utilized in the food industry and antibiotics development. Here, we determine the complete nucleotide sequence of the genome of Pediococcus acidilactici ATCC 8042. The genome was sequenced by the PacBio RSII to generate a single contig consisting of circular chromosome sequence. Illumina MiniSeq sequencing platform and Sanger sequencing method were additionally utilized to correct errors resulting from the long-read sequencing platform. The sequence consists of 2,009,598 bp with a G + C content of 42.1% and contains 1,865 protein-coding sequences. Based on the sequence information, we could confirm and predict the presence of four peptidoglycan hydrolases by HyPe software. This work, therefore, provides the complete genomic information of P. acidilactici ATCC 8042 with a profitable potential of genome-scale comprehension of anti-pathogenic activity, which can be applied in nutraceutical and pharmaceutical biotechnology field.


April 21, 2020

Koumiss consumption modulates gut microbiota, increases plasma high density cholesterol, decreases immunoglobulin G and albumin

Hyperlipidemia is a risk factor for cardiovascular disease and has become a significant public health problem. In this study, PacBio single-molecule real-time sequencing technology combined with a metabolomics study of koumiss revealed a series of changes in serum lipids, gut microbiota and viscera indices in hyperlipidemia patients 0, 30 and 60?days following daily koumiss treatment. High density lipoprotein cholesterol concentrations significantly increased, while levels of immunoglobulin G and albumin significantly decreased after koumiss treatment. Moreover, the abundance of some Bacteroides, Dorea and Catenibacterium species increased, whereas the abundance of Clostridium and Citrobacter species decreased. Our results indicate that koumiss consumption alleviates the symptoms of hyperlipidemia. This is associated with both the bacterial composition of the koumiss, particularly Lactobacillus and Streptococcus species, and the metabolites present in koumiss, such as s-adenosyl-l-methionine, carnosine, lysophosphatidylinositol and dipeptides. This study provides insight into the mechanisms underpinning the effects of koumiss on hypolipidemic symptoms.


April 21, 2020

Genome mining and metabolic profiling illuminate the chemistry driving diverse biological activities of Bacillus siamensis SCSIO 05746.

Bacillus spp. are important producers of bioactive natural products with potential applications in medicine and agriculture. Bacillus sp. SCSIO 05476 from a deep-sea sediment exhibits broad-spectrum antimicrobial activities and strong cytotoxic activity. Here, an integrative approach combining genome mining and metabolic profiling has been applied to decipher the chemical origins of this strain’s varied and significant biological activities. First, genome mining revealed 19 candidate gene clusters encoding the biosynthesis of diverse secondary metabolites. Then, a series of bacillibactins, fengycins, bacillomycins, surfactins, bacillaenes, macrolactins, and related species were found by LC-DAD-MS. Finally, three new linear bacillibactins, linbacillibactins A-C (1-3), along with 11 known secondary metabolites, bacillibactin (4), normal-C13 Val7 surfactin (5), anteiso-C13 Leu7 surfactin (6), iso-C14 Leu7 surfactin (7), normal-C14 Leu7 surfactin (8), anteiso-C14 Leu7 surfactin (9), macrolactin D (10), normal-C14 bacillomycin D (11), iso-C16 bacillomycin D (12), normal-C17 bacillomycin D (13), and iso-C17 bacillomycin D (14), were obtained and elucidated by bioactivity and structure-guided isolation from the fermentation of strain SCSIO 05746. Among them, new compounds 1-3 show significant siderophore activities comparable to that of bacillibactin (4), compounds 13 and 14 exhibit strong cytotoxic activity. At the same time, the strain classification status was confirmed by genomic analyses, and the complete genome sequence of Bacillus siamensis was presented firstly. This study provides a foundation for understanding the mechanisms driving SCSIO 05746’s multiple bioactivities and demonstrates a successful way of discovering bioactive metabolites using a combination of genome mining and metabolic profiling methods.


April 21, 2020

Distribution and characterization of N-acylhomoserine lactone (AHL)-degrading activity and AHL lactonase gene (qsdS) in Sphingopyxis.

N-Acylhomoserine lactone (AHL)-degrading enzyme is identified from the various environments and applied for quorum-sensing inhibition. In this study, we isolated two AHL-degrading strains, Sphingopyxis sp. EG6 and FD7, from the industrial cooling water samples. When the eight Sphingopyxis type strains were checked for the AHL-degrading activity, two strains, Sphingopyxis alaskensis DSM 13593 and Sphingopyxis bauzanensis DSM 22271, showed high AHL-degrading activity. The complete genome sequences of EG6 and FD7 revealed the presence of gene homolog of qsdS, which encodes AHL-lactonase in Sphingomonas ursincola. The qsdS gene is seated between putative gene homologs involved in 3-isopropylmalate dehydratase large (leuC2) and small (leuD) subunits in the genome of EG6, FD7, DSM 13593, and DSM 22271, but completely disappeared between leuC2 and leuD in the genome sequences of Sphingopyxis type strains without AHL-degrading activity. Purified His-tagged QsdS showed high AHL-degrading activity and catalyzed AHL ring opening by hydrolyzing lactones. In addition, heterologous expression of qsdS in Pseudomonas aeruginosa resulted in reduction of biofilm formation. These results suggested that the AHL-degrading activity in Sphingopyxis is useful as an effective agent for biofilm inhibition.Copyright © 2018 The Society for Biotechnology, Japan. Published by Elsevier B.V. All rights reserved.


April 21, 2020

Genome-wide analysis of methyl jasmonate-regulated isoform expression in the medicinal plant Andrographis paniculata

Alternative splicing can increase the complexity of the transcriptome and proteome. The most common mechanism of alternative splicing in plants is intron retention (IR), and the expression levels of IR isoforms can be differentially regulated when facing abiotic stress. The full-length transcriptome of the medicinal plant Andrographis paniculata was sequenced using both Illumina- and SMRT-based RNA-seq and a total of 4846 IR isoforms were identified. The expression levels of 310/296 IR isoforms were up-regulated, and 629/659 IR isoforms were down-regulated at 24?h/48?h after methyl jasmonate (MeJA) treatment, respectively. In the (E,E,E)-geranylgeranyl diphosphate (GGPP) biosynthesis pathway which contributes to the andrographolide biosynthesis, eight genes were alternatively spliced, resulting in a total of 25 isoforms, of which 12 are IR isoforms. After MeJA treatment, four of these IR isoforms showed significant differential expression. RT-PCR and qRT-PCR experiments confirmed the existence of five IR isoforms. This research deepens our understanding of the A. paniculata transcriptome and can assist in the future study of andrographolide biosynthesis.


April 21, 2020

Physiological properties and genetic analysis related to exopolysaccharide (EPS) production in the fresh-water unicellular cyanobacterium Aphanothece sacrum (Suizenji Nori).

The clonal strains, phycoerythrin(PE)-rich- and PE-poor strains, of the unicellular, fresh water cyanobacterium Aphanothece sacrum (Suringar) Okada (Suizenji Nori, in Japanese) were isolated from traditional open-air aquafarms in Japan. A. sacrum appeared to be oligotrophic on the basis of its growth characteristics. The optimum temperature for growth was around 20°C. Maximum growth and biomass increase at 20°C was obtained under light intensities between 40 to 80 µmol m-2 s-1 (fluorescent lamps, 12 h light/12 h dark cycles) and between 40 to 120 µmol m-2 s-1 for PE-rich and PE-poor strains, respectively, of A. sacrum . Purified exopolysaccharide (EPS) of A. sacrum has a molecular weight of ca. 104 kDa with five major monosaccharides (glucose, xylose, rhamnose, galactose and mannose; =85 mol%). We also deciphered the whole genome sequence of the two strains of A. sacrum. The putative genes involved in the polymerization, chain length control, and export of EPS would contribute to understand the biosynthetic process of their extremely high molecular weight EPS. The putative genes encoding Wzx-Wzy-Wzz- and Wza-Wzb-Wzc were conserved in the A. sacrum strains FPU1 and FPU3. This result suggests that the Wzy-dependent pathway participates in the EPS production of A. sacrum.


April 21, 2020

Investigating the bacterial microbiota of traditional fermented dairy products using propidium monoazide with single-molecule real-time sequencing.

Traditional fermented dairy foods have been the major components of the Mongolian diet for millennia. In this study, we used propidium monoazide (PMA; binds to DNA of nonviable cells so that only viable cells are enumerated) and single-molecule real-time sequencing (SMRT) technology to investigate the total and viable bacterial compositions of 19 traditional fermented dairy foods, including koumiss from Inner Mongolia (KIM), koumiss from Mongolia (KM), and fermented cow milk from Mongolia (CM); sample groups treated with PMA were designated PKIM, PKM, and PCM. Full-length 16S rRNA sequencing identified 195 bacterial species in 121 genera and 13 phyla in PMA-treated and untreated samples. The PMA-treated and untreated samples differed significantly in their bacterial community composition and a-diversity values. The predominant species in KM, KIM, and CM were Lactobacillus helveticus, Streptococcus parauberis, and Lactobacillus delbrueckii, whereas the predominant species in PKM, PKIM, and PCM were Enterobacter xiangfangensis, Lactobacillus helveticus, and E. xiangfangensis, respectively. Weighted and unweighted principal coordinate analyses showed a clear clustering pattern with good separation and only minor overlapping. In addition, a pure culture method was performed to obtain lactic acid bacteria resources in dairy samples according to the results of SMRT sequencing. A total of 102 LAB strains were identified and Lb. helveticus (68.63%) was the most abundant, in agreement with SMRT sequencing results. Our results revealed that the bacterial communities of traditional dairy foods are complex and vary by type of fermented dairy product. The PMA treatment induced significant changes in bacterial community structure.Copyright © 2019 American Dairy Science Association. Published by Elsevier Inc. All rights reserved.


April 21, 2020

Potential use of the Pteris vittata arsenic hyperaccumulation-regulation network for phytoremediation.

Arsenic accumulation in soil is a global problem typically addressed using phytoremediation methods. Pteris vittata, a model arsenic hyperaccumulator, has great potential as a genetically engineered plant for phytoremediation. However, the lack of omic information on this species has severely limited the identification and application of its arsenic hyperaccumulation and regulation components. In this study, we used an optimized single-molecular real-time (SMRT) strategy to create a de novo full-length transcriptomic-tonoplast proteomic database for this unsequenced fern and to determine the genetic components underlying its arsenic hyperaccumulation-regulation mechanisms. We established a comprehensive network consisting of six major transporter families, two novel resistance pathways, and a regulatory system by examining alternative splicing (AS) and long non-coding RNA (lncRNA) in different tissues following As(III) and As(V) treatment. The database and network established in this study will deepen our understanding of the unique hyperaccumulation and regulation mechanisms of P. vittata, ultimately providing a valuable resource for futher research on phytoremediation of arsenic-contaminated soil. Copyright © 2019 Elsevier B.V. All rights reserved.


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