Roseovarius pelagicus sp. nov., a facultatively anaerobic bacterium with potential for degrading polypropylene, isolated from Arctic seawater.

A Gram-stain-negative, facultatively anaerobic, non-motile, rod-shaped bacterial strain, designated HL-MP18T, was isolated from Arctic seawater after a prolonged incubation employing polypropylene as the sole carbon source. Phylogenetic analyses of the 16S rRNA gene sequence revealed that strain HL-MP18T was affiliated to the genus Roseovarius with close relatives Roseovarius carneus LXJ103T (96.8 %) and Roseovarius litorisediminis KCTC 32327T (96.5 %). The complete genome sequence of strain HL-MP18T comprised a circular chromosome of 3.86 Mbp and two circular plasmids of 0.17 and 0.24 Mbp. Genomic comparisons based on average nucleotide identity and digital DNA-DNA hybridization showed that strain HL-MP18T was consistently discriminated from its closely related taxa in the genus Roseovarius. Strain HL-MP18T showed optimal growth at 25 °C, pH 7.0 and 2.5 % (w/v) sea salts. The major cellular fatty acids were C18 : 1 ω6c and/or C18 : 1 ω7c (49.6 %), C19 : 0 cyclo ω8c (13.5 %), and C16 : 0 (12.8 %). The major respiratory quinone was ubiquinone-10. The polar lipids consisted of phosphatidylcholine, phosphatidylglycerol, an unidentified aminolipid and three unidentified lipids. The genomic DNA G+C content of the strain was 59.2 mol%. The phylogenetic, genomic, phenotypic and chemotaxonomic results indicate that strain HL-MP18T is distinguishable from the recognized species of the genus Roseovarius. Therefore, we propose that strain HL-MP18T represents a novel species belonging to the genus Roseovarius, for which the name Roseovarius pelagicus sp. nov. is proposed. The type strain is HL-MP18T (=KCCM 90405T=JCM 35639T).

Arctic Ocean sediments as important current and future sinks for marine microplastics missing in the global microplastic budget.

To better understand unexpectedly low plastic loads at the ocean's surface compared with inputs, unidentified sinks must be located. Here, we present the microplastic (MP) budget for multi-compartments in the western Arctic Ocean (WAO) and demonstrate that Arctic sediments serve as important current and future sinks for MPs missing from the global budget. We identified an increase of 3% year-1 in MP deposition from sediment core observations. Relatively elevated MP abundances were found in seawater and surface sediments around the summer sea ice retreat region, implying enhanced MP accumulation and deposition facilitated by the ice barrier. We estimate 15.7 ± 2.30 × 1016 N and 0.21 ± 0.14 MT as total MP loads in the WAO with 90% (by mass) buried in the post-1930 sediments, which exceeds the global average of the current marine MP load. The slower increase in plastic burial versus production implies a lag in plastic delivery to the Arctic, indicating more pollution in the future.

Microplastics in large marine animals stranded in the Republic of Korea.

Microplastics (MPs) are found in every ocean and are frequently ingested by marine animals. This study analyzed MPs in the stomachs and intestines of 12 large marine animals comprising one fin whale (Balaenoptera physalus), seven finless porpoises (Neophocaena asiaeorientalis), two loggerhead turtles (Caretta caretta), one Indo-Pacific bottlenose dolphin (Tursiops aduncus), and one common dolphin (Delphinus delphis) that were stranded off the Republic of Korea between 2019 and 2021. MPs were detected with a mean abundance of 3.42 ± 3.2 items/g and were predominantly of transparent-white, fragment-shaped polypropylene smaller than 200 µm. The abundance of MPs found did not correlate with the biological information (maturity, body length) of the finless porpoises and there were no significant differences in the abundance of MPs between the stomachs and intestines. These results cannot accurately assess the impact of MPs on large marine animals, so further studies are necessary to understand how MPs can potentially affect them.

Modeling of microplastics discharged from a station in Marian Cove, West Antarctica.

Conspicuous amounts of microplastics have been discovered in bays near Antarctic research stations, including several types of microplastics in the water columns of Marian Cove. This study proposes an efficient operating strategy for a wastewater treatment plant to mitigate microplastic accumulations in the bay by assessing the transport and accumulation of microplastics using numerical simulations. Hence, microplastic particles were classified into falling and rising particles to find a mechanism for their vertical migration. The results showed that the characteristics of the vertical migration of the particles and flow conditions critically determined their traveling distance and accumulation location. Further, the amount of microplastics accumulated in the cove depended on the release time of the wastewater during the tidal cycle. Wastewater treatment plants need to be improved to reduce microplastics. However, it is necessary to adjust the location and schedule for releasing them into Marian Cove.

Toward a long-term monitoring program for seawater plastic pollution in the north Pacific Ocean: Review and global comparison.

Through a literature survey and meta-data analysis, monitoring methods and contamination levels of marine micro- and macroplastics in seawater were compared between the North Pacific and the world's other ocean basins. The minimum cut-off size in sampling and/or analysis of microplastics was crucial to the comparison of monitoring data. The North Pacific was most actively monitored for microplastics and showed comparatively high levels in the global context, while the Mediterranean Sea was most frequently monitored for macroplastics. Of the 65 extracted mean abundances of microplastics in seawater from the North Pacific, two (3.1%) exceeded the lowest predicted no-effect concentration (PNEC) proposed thus far. However, in the context of business-as-usual conditions, the PNEC exceedance probability may be expected to reach 27.7% in the North Pacific in 2100. The abundance of marine plastics in seawater, which reflects the current pollution status and marine organisms' waterborne exposure levels, is a useful indicator for marine plastic pollution. For regional and global assessments of pollution status across space and time, as well as assessment of ecological risk, two microplastic monitoring approaches are recommended along with their key aspects. Although microplastic pollution is closely linked with macroplastics, the monitoring data available for floating macroplastics and more extent to mesoplastics in most ocean basins are limited. A more specific framework for visual macroplastic survey (e.g. fixed minimum cut-off size, along with survey transect width and length according to survey vessel class) is required to facilitate data comparison. With the implementation of standardised methods, increased efforts are required to gather monitoring data for microplastics and-more importantly-floating macroplastics in seawater worldwide.

Biokinetics of fluorophore-conjugated polystyrene microplastics in marine mussels.

Biokinetic information on microplastics in bivalves is required to reduce the human exposure, but little is known about the time-course and size effect on tissue absorption and clearance. The biokinetics of fluorophore-labeled polystyrene microbeads with diameters 10 µm (PL10) and 90 µm (PL90) in Mytilus galloprovincialis marine mussels was investigated in the present study. It was found that both PL10 and PL90 showed a biphasic tissue distribution pattern in digestive and non-digestive tissues, highlighting the significant tissue distribution starting from 48 h post-treatment. The differential size effect on tissue distribution was observed only in the gills, which suggests that PL10 accumulates more than PL90. The depuration kinetics show that particles of both sizes can be cleared in any tissue, but non-digestive tissue requires a longer duration for depuration than digestive tissue. The differential size effect on depuration was observed for both digestive and non-digestive tissues, suggesting that PL10 needed a longer duration for depuration than PL90. More than seven days were needed for depuration of microplastics in mussels, which is an exceptionally longer period compared to conventional depuration of bivalves. The most significant improvement of this study is providing the biokinetics of two different-sized microplastics in mussels and the differential time for purging microplastics from mussels.

Importance of seasonal sea ice in the western Arctic ocean to the Arctic and global microplastic budgets.

Arctic sea ice entraps microplastics (MP) from seawater and atmosphere and is recognized as sink and transport vector of MPs. However, ice-trapped fraction in the global MP budget, contribution of atmospheric input, and linkage among Arctic basins remain unclear. To assess them, we investigated the number- and mass-based data separated by size and shape geometry for MPs in sea ice, snow, and melt pond water from the western Arctic Ocean (WAO). A significant dependency of MP data on measured cutoff size and geometry was found. For the same size range and geometry, sea ice MPs in WAO ((11.4 ± 9.12) × 103 N m-3 for ≥ 100 µm) were within comparable levels with those in other Arctic basins, but showed closer similarity in polymer and shape compositions between WAO and Arctic Central Basin, indicating the strong linkage of the two basins by the Transpolar Drift. Our budgeting shows that a significant amount of plastic particles ((3.4 ± 2.6) × 1016 N; 280 ± 701 kilotons), which are missed from the global inventory, is trapped in WAO seasonal sea ice, with < 1% snowfall contribution. Our findings highlight that WAO ice zone may play a role as a sink of global MPs as well as a source of Arctic MPs.

Variation and Uncertainty of Microplastics in Commercial Table Salts: Critical Review and Validation.

Increasing concern of human exposure to microplastics (MPs) necessitates an assessment of the quality of MP data relevant to human exposure. In this literature review for table salt, we addressed the variability and uncertainty of MP data caused by different analytical methods among studies. Additionally, validation experiment was conducted to identify and correct uncertainties related to MP size. When combined without validation, salt data in literature (n = 150) showed a wide range of 0-39800 (1386 ±â€¯5477) MPs kg-1. All procedures, including sample treatment, MP identification, and quality assurance were related to this variability. Most serious variability originated from the MP identification methods associated with minimum cut-off size of targeted/measured MPs and the selection of particles identified. When not corrected by size, MP content differed by 10-600 times among MP identification methods, with greatest value from visual observation, followed by FTIR and Raman methods. Meanwhile, there was a significant correlation-regardless of identification method-between logarithmic mean abundances and minimum cut-off sizes. The size-corrected values showed that adults intake up to 19000 MPs ≥10 µm annually via table salt, compared with 5100 MPs that was estimated from uncorrected mean abundance. Our validation experiment also showed the possibility of serious errors being caused by arbitrary selection of "MP-like particles" in spectroscopic analysis, specifically for smaller-sized particles. A combination of unverified data originated from different methods might have failed to adequately produce reliable human health-relevant results, thereby undermining the ability to quantify human risk.

Abundance and characteristics of microplastics in soils with different agricultural practices: Importance of sources with internal origin and environmental fate.

Despite intensive use of plastics in agriculture, little is known about the occurrence of microplastics (MPs) in agro-environment. To identify the effect of internal sources and environmental fate on MP appearance in farmland, we examined four soil types with different agricultural practices representing either direct application of polyethylene (PE) film-the inside (GS-in) and outside (GS-out) soils of greenhouse and mulch-film use soils (MS)-or rare use of plastics (rice-paddy soils; RS). MP abundance was 10-7630 items kg-1, with the order of GS-in, GS-out, RS, and MS. Besides the highest MP abundance, rare PE-sheet (4% of MPs) and increased MP abundance with sizes decreasing were unique for GS-in, implying the presence of internal sources other than PE-film and continued MP accumulation. Contrarily, in other outside soils high PE-sheet appearance (10-31%) indicated substantial input via fragmentation of applied PE-film (for GS-out and MS) or via surface-runoff (for RS) while drastic decline of small-sized MPs in order of MS > RS > GS-out than expected from steady-state fragmentation implied significant removal of MPs by surface runoff and/or infiltration. Our results suggest the importance of internal sources and environmental fate as significant factors affecting the occurrence of MPs in agricultural soils.

Environmental Distribution of Styrene Oligomers (SOs) Coupled with Their Source Characteristics: Tracing the Origin of SOs in the Environment.

Despite growing concerns regarding plastic additives, their environmental fate coupled with leaching from source materials are not well known. Styrene oligomers (SOs), which are unintended additives in expanded polystyrene (EPS), are estrogenic micropollutants. Here, we identified the effects of their potential sources (i.e., EPS buoy and its leachate) and environmental dilution on SO distribution within coastal sediments. SO content in fresh EPS particles was 0.1% (w/w), dominated by 2,4,6-triphenyl-hexene (ST-1), while 2,4-diphenyl-1-butene (SD-2) accounted for most of the SOs in EPS leachate, indicating its faster leachability. In lake and offshore environments, the SO composition profiles from their terrestrial inputs and inner sites were similar to those of EPS leachate; meanwhile, the exponentially decreasing SO concentration and increasing styrene trimers (STs) fraction with distance from the inner to outer sites were evident. These profiles indicated continuous SO leaching from their potential sources in the inland, followed by a change in SOs due to environmental dilution. SOs in beach sediment implied the presence of micro-sized EPS particles. We suggest the ST-1 to SD-2 ratio as an index to differentiate among freshly leached SOs (∼0.02), environmentally diluted SOs after leaching (∼0.1), SOs in fresh EPS (∼1.2), and SOs in aged EPS (> 2).

Exposure to sublethal concentrations of zinc pyrithione inhibits growth and survival of marine polychaete through induction of oxidative stress and DNA damage.

Effects of zinc pyrithione (ZnPT) and inorganic Zn (ZnCl2) were evaluated on a marine polychaete at sublethal concentrations for 14 days. ZnPT decreased the burrowing activity and AChE activity with higher acute toxicities, implying its cholinergic effect. Both ZnPT and ZnCl2 increased MDA levels at higher concentrations, suggesting lipid peroxidation and oxidative stress. In the ZnPT-treated polychaete, enzymatic activities of CAT and SOD were elevated with an increase in DNA damage, whereas the levels of GSH, GPx, GR, and GST were decreased. However, in the ZnCl2-treated polychaete, the level of GSH and enzymatic activities of CAT, SOD, GPx, GR, and GST were significantly elevated to resist cellular damage. During 97 days depuration experiment, significant mortality and growth retardation were observed in the ZnPT-exposed polychaete. Overall, ZnPT was found to be more toxic than ZnCl2 with the harmful impact on antioxidant defense system and DNA stability in marine polychaete.

Horizontal and vertical distribution of phthalates acid ester (PAEs) in seawater and sediment of East China Sea and Korean South Sea: Traces of plastic debris?

Phthalate acid esters (PAEs) are commonly used as plasticizers in numerous plastic applications. Owing to their high leachability, the occurrence of PAEs can be used to trace plastic pollution. The northwest Pacific marginal seas, including the East China Sea, are suspected not only to be the area that receives the most plastic waste globally but also transit the waste to the ocean worldwide. To identify the potential sources of PAEs in this area, seawater at different water depths and sediment were investigated. The highest level of di(2-ethylhexyl) phthalate (DEHP), which is primarily used in plastic polymers, was observed in the accumulation zone of plastic debris. Moreover, DEHP exhibited not only the highest levels in the bottom layer of water column but also a significant correlation between bottom water layer and bed sediment, which strongly suggests a continuous flow of PAEs from the seafloor to the seawater column in this area.

Temporal and spatial variations in hydrophobicity dependence of field-derived metrics to assess the biomagnification potential of hydrophobic organochlorine compounds.

The bioaccumulation potential ("B") of compounds is one of the major considerations in assessing chemical hazards. A variety of metrics, including hydrophobicity (KOW), bioconcentration factor (BCF), bioaccumulation factor (BAF), and to an increasing degree biomagnification factor (BMF) and trophic magnification factor (TMF), are widely used to characterize "B". In the present study, the variation and hydrophobicity-dependence of each of these metrics for recalcitrant hydrophobic organochlorine compounds (HOCs) was determined from four food webs collected in two different seasons at two different sites of the Han River, Korea. Measured environmental parameters and stable isotopic ratios exhibited distinct seasonal and spatial shifts in the ecological condition of the river. The observed values of individual metrics were positively and linearly related with their log KOW values, but linearized slopes differed significantly among the four food webs, with the largest variation being exhibited by TMF and log fugacity ratio (log F) followed by log BMF > log BAF. When based on field-derived mean linear equations, different log KOW values were obtained for a critical point for the identification of biomagnification of HOCs. Consequently, the biomagnification potential of HOCs and its relationship with KOW can vary, being seriously affected by not only on the metrics used for its assessment but also on spatial and temporal variations in ecological conditions. Our results indicate that TMF for "B" might be more robust than the other metrics but the development of new methodologies to reduce uncertainty and to enhance the accuracy of TMFs by correcting for ecological variation, together with addition efforts to harmonize individual metrics for "B".

Global Pattern of Microplastics (MPs) in Commercial Food-Grade Salts: Sea Salt as an Indicator of Seawater MP Pollution.

Previous studies have identified microplastics (MPs) in commercial table salts but could not exactly address the origin of the MPs because of several limitations. The present study is based on the hypothesis that commercial sea salts can act as an indicator of MP pollution in the surrounding environment unless the MPs are filtered out during the manufacturing process. A total of 39 different salt brands produced at geospatially different sites, including 28 sea salt brands from 16 countries/regions on six continents, were investigated. A wide range of MP content (in number of MPs per kg of salt; n/kg) was found: 0-1674 n/kg (excluding one outlier of 13 629 n/kg) in sea salts, 0-148 n/kg in rock salt, and 28-462 n/kg in lake salt. Relatively high MP content was identified in sea salts produced in Asian countries/regions. The abundance of MPs in unrefined sea salts ( n = 25) exhibited significant linear correlations with plastic emissions from worldwide rivers ( r2= 0.33; p = 0.003) and with the MP pollution levels in surrounding seawater ( r2= 0.46; p = 0.021) in the published literature. The results indicate that not only is Asia a hot spot of global plastic pollution, as previous studies have suggested, but also that sea salt can be a good indicator of the magnitude of MP pollution in the surrounding marine environment.

The effect of the inspiratory muscle training on functional ability in stroke patients.

[Purpose] This study was to find out an inspiratory muscle training (IMT) program therapeutic effects on stroke patients' functional ability. [Subjects and Methods] Twenty stroke patients were assigned to one of two groups: inspiratory muscle training (n=10), and control (n=10), randomization. The inspiratory muscle training participants undertook an exercise program for 30 minute per times, 5 times a week for 6 weeks. The investigator measured the patients' trunk impairment scale (TIS) and 6 minute walking test (6MW) for functional ability before and after IMT. [Results] The TIS appeared some significant differences in both groups before and after the training. The 6MW test showed some significant differences in the inspiratory muscle training group, but didn't show any significant difference in the control group. And the differences in both groups after depending the inspiratory muscle training were significantly found in the tests of TIS and 6MW test [Conclusion] The results showed that the inspiratory muscle training in stroke patients are correlated with the trunk stability and locomotion ability, suggesting that physical therapist must take into consideration the inspiratory muscle training, as well as functional training to improve physical function in stroke patients.

The relationship between non-affected forelimb exercise and recovery after focal cerebral ischemia in acute phase.

[Purpose] In the present study, we hypothesized that exercise of the nonaffected forelimb in the early poststroke phase would stimulate the intact hemisphere, thereby influencing the hemisphere of the infarcted side and improving the performance of the hemiplegic limb. [Subjects and Methods] Adult male Sprague-Dawley rats (8-10 weeks of age, weighing 250-300 g, n=12) were used and randomly divided into 3 groups: nonaffected forelimb exercise for 3 days and treadmill exercise 7 days after ischemia (ETF, n=6), resting for 3 days and treadmill exercise 7 days after ischemia (ETN, n=6), and after ischemia 10 days resting group. To validate nerve growth factor (NGF), western blot analysis was performed. The results were analyzed using SPSS for Windows version 18.0. and expressed as mean ± standard deviation (SD). [Results] Early treadmill exercise increased the expression of NGF protein level in both ETE and ETN groups. Comparing between the nonaffected forelimb exercise and infarct hemisphere in NGF protein expression, the ETE group showed higher increase of NGF protein level in right hemisphere than ETN group, but there was no statistical significance. [Conclusion] The early treadmill exercise increased NGF protein expression levels in both hemispheres and the nonaffected forelimb exercise in the early poststroke recovery phase could enhance neuronal recovery after focal ischemia in rat models.

The effect of horse-riding simulator exercise on the gait, muscle strength and muscle activation in elderly people with knee osteoarthritis.

[Purpose] The aim of this study was to examine the effects of horse-riding simulator exercise on gait ability and muscle strength, muscle activation in elderly with knee osteoarthritis. [Subjects and Methods] Thirty elderly patients with knee osteoarthritis were recruited, a horse-riding simulator group consisted of fifteen subjects and they performed exercise three times a week for eight weeks. And each exercise was performed, horse riding simulator exercise for 15 minutes and knee strengthening exercise for 15 minutes. Knee strengthening exercise group consisted of fifteen subjects and performed knee strengthening exercise for 30 minutes. [Results] The horse-riding simulator group showed significant differences after the intervention in timed 10-meter walk test (10MWT), muscle strength, muscle activation. [Conclusion] The results of this study indicate that horse-riding simulator exercise is effective on knee osteoarthritis. Therefore, horse-riding simulator exercise can be used for gait training for knee osteoarthritis.

Monitoring of styrene oligomers as indicators of polystyrene plastic pollution in the North-West Pacific Ocean.

Styrene oligomers (SOs) as global contaminants are an environmental concern. However, little is known on the distribution of SOs in the ocean. Here, we show the distribution of anthropogenic SOs generated from discarded polystyrene (PS) plastic monitored from the coastal ocean surface waters (horizontal distribution) and deep seawaters (vertical distribution) in the North-West Pacific Ocean. SOs concentrations in surface seawater and deep seawater ranged from 0.17 to 4.26 µg L-1 (total mean: 1.48 ± 1.23 µg L-1) and from 0.31 to 4.31 µg L-1 (total mean: 1.32 ± 0.87 µg L-1), respectively. Since there is no significant difference in the mean concentrations, SOs seems to be spread across marine environment selected in this study. Nevertheless, regional SOs appears to persist to varying degrees with their broad horizontal and vertical distribution in the ocean. Each horizontal and vertical distribution of SOs differs by approximately 1.95-2.57 times, probably depending on the events of weather and global ocean circulation. These results provide the distribution pattern of SOs for assessing environmental pollution arising from PS plastic.

The effects of horse-riding simulator exercise on balance in elderly with knee osteoarthritis.

[Purpose] The aim of this study was to examine the effects of horse-riding simulator exercise on balance in elderly with knee osteoarthritis. [Subjects and Methods] Fifty elderly patients with knee osteoarthritis were recruited, a horse-riding simulator group performed exercise three times a week for eight weeks. And each exercise was performed for 30 minutes. [Results] The horse-riding simulator group showed significant differences after the intervention in Short Form Berg Balance Scale, Functional reaching test. [Conclusion] The results of this study indicate that horse-riding simulator exercise is effective on knee osteoarthritis. Therefore, horse-riding simulator exercise can be used balance training for knee osteoarthritis.

Influence of Number Fluctuation and Position Variation of Channel Dopants and Gate Metal Grains on Tunneling Field-Effect Transistors (TFETs).

The influence of number fluctuation and position variation on channel dopants and gate metal grains on tunneling field-effect transistors (TFETs) have been discussed in comparison with metal-oxide-semiconductor FETs (MOSFETs). Based on the simulation results of randomly generated device samples, the shape of the statistical threshold voltage (V(th)) distribution of TFETs associated with individual variation sources such as random dopant fluctuation (RDF) and work-function variation (WFV) have been found to be significantly different than that of MOSFETs. This analysis provides a detailed insight into the variation sources related to underlying physics of TFETs.