Optimization of suspect and non-target analytical methods using GC/TOF for prioritization of emerging contaminants in the Arctic environment.

Numerous chemicals have been manufactured through industrial activities and used as consumer products since the late 18th century. Non-target analysis is a new analytical tool to detect many chemicals in environmental samples and to prioritize emerging contaminants. In this study, suspect and non-target analytical methods were optimized using gas chromatography coupled with time-of-flight (GC/TOF) to propose contaminants of emerging concern for the Arctic environment.

Simultaneous and Synergic Production of Bioavailable Iron and Reactive Iodine Species in Ice.

The bioavailable iron is essential for all living organisms, and the dissolution of iron oxide contained in dust and soil is one of the major sources of bioavailable iron in nature. Iodine in the polar atmosphere is related to ozone depletion, mercury oxidation, and cloud condensation nuclei formation. Here we show that the chemical reaction between iron oxides and iodide (I) is markedly accelerated to produce bioavailable iron (Fe(II)) and tri-iodide (I: evaporable in the form of I) in frozen solution (both with and without light irradiation), while it is negligible in aqueous phase.

Nitrite-Induced Activation of Iodate into Molecular Iodine in Frozen Solution.

A new mechanism for the abiotic production of molecular iodine (I) from iodate (IO), which is the most abundant iodine species, in dark conditions was identified and investigated. The production of I in aqueous solution containing IO and nitrite (NO) at 25 °C was negligible. However, the redox chemical reaction between IO and NO rapidly proceeded in frozen solution at -20 °C, which resulted in the production of I, I, and NO.

Nanopore sequencing reads improve assembly and gene annotation of the Parochlus steinenii genome.

Parochlus steinenii is a winged midge from King George Island. It is cold-tolerant and endures the harsh Antarctic winter. Previously, we reported the genome of this midge, but the genome assembly with short reads had limited contig contiguity, which reduced the completeness of the genome assembly and the annotated gene sets.

Characterization and mutation anaylsis of a cold-active bacterial hormone-sensitive lipase from Salinisphaera sp. P7-4.

In mammals, hormone sensitive lipase (EC 3.1.1.

Structural and functional analysis of a dimeric fumarylacetoacetate hydrolase (EaFAH) from psychrophilic Exiguobacterium antarcticum.

Fumarylacetoacetate hydrolase (FAH) is essential for the degradation of aromatic amino acids as well as for the cleavage of carbon-carbon bonds in metabolites or small organic compounds. Here, the X-ray crystal structure of EaFAH, a dimeric fumarylacetoacetate hydrolase from Exiguobacterium antarcticum, was determined, and its functional properties were investigated using biochemical methods. EaFAH adopts a mixed β-sandwich roll fold with a highly flexible lid region (Val-Leu), and an Mg ion is bound at the active site by coordinating to the three carboxylate oxygen atoms of Glu, Glu, and Asp.

Ligand-Specific Dissolution of Iron Oxides in Frozen Solutions.

The freezing-enhanced dissolution of iron oxides by various ligands has been recently proposed as a new mechanism that may influence the supply of bioavailable iron in frozen environments. The ligand-induced dissolution of iron oxides is sensitively affected by the kind and concentration of ligands, pH, and kind of iron oxides. While most ligands are thought to be freeze-concentrated in the ice grain boundary region along with iron oxides to enhance the iron dissolution, this study found that some ligands, such as ascorbic acid, suppress the iron dissolution in frozen solution relative to that in aqueous solution.

Embryos of an Antarctic zooplankton require anoxia for dormancy, are permeable to lipophilic chemicals, and reside in sediments containing PCBs.

Zooplankton in Antarctic maritime lakes face challenges imposed by anthropogenic chemicals. Studies on temperate species suggest that lipophilic chemicals will accumulate in dormant embryos of Antarctic zooplankton and decrease hatching success, thereby threatening centuries of accumulated genetic diversity that would increase population resilience in the face of climate change. We evaluated the potential for lakes to act as sinks for legacy pollutants in the maritime Antarctic by testing sediments for polychlorinated biphenyls (PCBs) previously identified in soil, flora and fauna of lake catchments.

Soil pH rather than elevation determines bacterial phylogenetic community assembly on Mt. Norikura.

There is considerable interest in the factors which may explain variation in microbial community assembly processes. In this study, we investigated bacterial community assembly, phylogenetic diversity and the relative role of deterministic and stochastic processes along environmental gradients on Mt. Norikura, Japan.

Modulating α-synuclein fibril formation using DNA tetrahedron nanostructures.

The small presynaptic protein α-synuclein (α-syn) is involved in the etiology of Parkinson's disease owing to its abnormal misfolding. To date, little information is known on the role of DNA nanostructures in the formation of α-syn amyloid fibrils. Here, the effects of DNA tetrahedrons on the formation of α-syn amyloid fibrils were investigated using various biochemical and biophysical methods such as thioflavin T fluorescence assay, atomic force microscopy, light scattering, transmission electron microscopy, and cell-based cytotoxicity assay.

The genome of common long-arm octopus Octopus minor.

Background: 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.

Findings: The final genome assembly of O.

Band Ratios Matrix Transformation (BRMT): A Sedimentary Lithology Mapping Approach Using ASTER Satellite Sensor.

Remote sensing imagery has become an operative and applicable tool for the preparation of geological maps by reducing the costs and increasing the precision. In this study, ASTER satellite remote sensing data were used to extract lithological information of Deh-Molla sedimentary succession, which is located in the southwest of Shahrood city, Semnan Province, North Iran. A robust and effective approach named Band Ratio Matrix Transformation (BRMT) was developed to characterize and discriminate the boundary of sedimentary rock formations in Deh-Molla region.

Synthesis of mycosporine-like amino acids by a size-fractionated marine phytoplankton community of the arctic beaufort sea.

During the RV-ARAON cruise, a comparative study on the biosynthesis of mycosporine-like amino acids (MAAs) was conducted for the size-fractionated phytoplankton of the Beaufort Sea (Arctic). The MAAs contents in the micro-phytoplankton community (>20 μm size) is considerably higher than that observed in the nano- (20-2 μm size) and pico-phytoplankton (<2 μm size) communities. The micro-phytoplankton of the Mackenzie Shelf had a relatively higher Chlorophyll a (Chl a) concentration.

Proteomic comparison of selective breeding and growth hormone transgenesis in fish: Unique pathways to enhanced growth.

In fish used for food production and scientific research, fast growth can be achieved via selective breeding or induced instantaneously via growth hormone (GH) transgenesis (GHT). The proteomic basis for these distinct routes towards a similar higher phenotype remains uncharacterized, as are associated implications for health parameters. We addressed this knowledge gap using skeletal muscle proteomics in coho salmon (Oncorhynchus kisutch), hypothesising that i) selective breeding and GHT are underpinned by both parallel and unique changes in growth systems, and ii) rapidly-growing fish strains have lowered scope to allocate resources towards immune function.

Biochemical characterization of a thermostable cobalt- or copper-dependent polyphenol oxidase with dye decolorizing ability from Geobacillus sp. JS12.

A putative laccase-like gene, GPPO, encoding a protein of 17.2 kDa and belonging to the multicopper oxidase family, was cloned and overexpressed in Escherichia coli cells. The purified recombinant protein GPPO is homodecameric protein with a molecular weight of 171.

Activation of Periodate by Freezing for the Degradation of Aqueous Organic Pollutants.

A new strategy (i.e., freezing) for the activation of IO for the degradation of aqueous organic pollutants was developed and investigated.

Optical and molecular characterization of dissolved organic matter (DOM) in the Arctic ice core and the underlying seawater (Cambridge Bay, Canada): Implication for increased autochthonous DOM during ice melting.

Sea ice contains a large amount of dissolved organic matter (DOM), which can be released into the ocean once it melts. In this study, Arctic sea ice DOM was characterized for its optical (fluorescence) properties as well as the molecular sizes and composition via size exclusion chromatography and Fourier transformation ion cyclotron resonance mass spectrometry (FT-ICR MS). Ice cores were collected along with the underlying seawater samples in Cambridge Bay, an Arctic area experiencing seasonal ice formation.

Occurrence and distribution of old and new halogenated flame retardants in mosses and lichens from the South Shetland Islands, Antarctica.

The spatial distribution of old and new halogenated flame retardants (HFRs), including polybrominated diphenyl ethers (PBDEs), hexabromocyclododecanes (HBCDs), and Dechlorane Plus (DPs) and related compounds (Dechloranes), were investigated in the South Shetland Islands of Antarctica, employing mosses (Andreaea depressinervis and Sanionia uncinata) and lichens (Himantormia lugubris and Usnea antarctica) as bioindicators. The levels of PBDEs, HBCDs, and Dechloranes ranged from 3.2 to 71.

Identification, characterization, immobilization, and mutational analysis of a novel acetylesterase with industrial potential (LaAcE) from Lactobacillus acidophilus.

Lactic acid bacteria, which are involved in the fermentation of vegetables, meats, and dairy products, are widely used for the productions of small organic molecules and bioactive peptides. Here, a novel acetylesterase (LaAcE) from Lactobacillus acidophilus NCFM was identified, functionally characterized, immobilized, and subjected to site-directed mutagenesis for biotechnological applications. The enzymatic properties of LaAcE were investigated using biochemical and biophysical methods including native polyacrylamide gel electrophoresis, acetic acid release, biochemical assays, enzyme kinetics, and spectroscopic methods.

Determinants of serum organochlorine pesticide and polychlorinated biphenyl levels in middle-aged Korean adults.

The serum levels of organochlorine pesticides (OCPs) and polychlorinated biphenyls (PCBs) were measured in a middle-aged Korean population and investigated associations with age, gender, body mass index (BMI), metabolic syndrome (MS), type 2 diabetes mellitus (T2DM), and dietary habits. The median concentrations of 22 OCPs and 34 PCBs in the serum samples were 483 and 216 ng g lipid, respectively. The most abundant compound was p,p'-DDE, followed by PCB 153, β-HCH, PCB 118, and PCB 180.

Pb concentrations and isotopic record preserved in northwest Greenland snow.

We present high-resolution lead (Pb) concentrations and isotopic ratios from a northwest Greenland snow pit covering a six-year period between 2003 and 2009. Pb concentrations ranged widely from 2.7 pg g to 97.

A Dynamic Energy Budget (DEB) model to describe Laternula elliptica (King, 1832) seasonal feeding and metabolism.

Antarctic marine organisms are adapted to an extreme environment, characterized by a very low but stable temperature and a strong seasonality in food availability arousing from variations in day length. Ocean organisms are particularly vulnerable to global climate change with some regions being impacted by temperature increase and changes in primary production. Climate change also affects the biotic components of marine ecosystems and has an impact on the distribution and seasonal physiology of Antarctic marine organisms.

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.

Antarctic ice shelf potentially stabilized by export of meltwater in surface river.

Meltwater stored in ponds and crevasses can weaken and fracture ice shelves, triggering their rapid disintegration. This ice-shelf collapse results in an increased flux of ice from adjacent glaciers and ice streams, thereby raising sea level globally. However, surface rivers forming on ice shelves could potentially export stored meltwater and prevent its destructive effects.

Genome sequencing of the winged midge, Parochlus steinenii, from the Antarctic Peninsula.

Background: In the Antarctic, only two species of Chironomidae occur naturally-the wingless midge, Belgica antarctica , and the winged midge, Parochlus steinenii . B. antarctica is an extremophile with unusual adaptations.