Search

This study evaluated the inhalation of mask-derived materials by simulating real breathing conditions and examined how the amount of inhaled materials varies with breathing flow rate and duration. Three types of non-certified reusable masks and two types of certified disposable masks were selected. For each mask, five different hazardous materials were captured and analyzed in three replicates with two breathing flow rates of 30 L/min and 85 L/min and two breathing time combinations of 15 min and 60 min. Nanoparticles and total volatile organic compounds (TVOC) were analyzed using a real-time instrument, volatile organic compounds (VOCs) and phthalates were analyzed using gas chromatography–mass spectrometry, and metal elements were analyzed using inductively coupled plasma-mass spectrometry. Inhaled nanoparticle number concentrations decreased when wearing the masks, with certified disposable masks showing higher nanoparticle filtration efficiency (>90 %) compared to non-certified reusable masks (

Background Phragmites australis is a common foundation species found in inland and brackish estuarine ecosystems. P. australis stands provide a wide range of habitats for wetland organisms and perform essential functions, such as nutrient cycling, pollutant filtration, wave energy reduction, and soil stabilization. However, excessive growth of P. australis can degrade the quality of wetland habitats, thereby reducing the functions of restored wetlands. Methods In this study, we investigated the effectiveness of vegetation management techniques, such as aboveground cutting and temporal inundation with varying depth and periodicity, in controlling the growth performance of P. australis and adjacent vegetation, Bolboschoenus planiculmis. Differences in growth responses to manipulated inundation stress between P. australis and B. planiculmis were measured. Results Inundation stress of 10–50 cm caused significantly greater inhibition of growth performance in B. planiculmis compared to P. australis. The combination of aboveground-cutting and inundation treatments resulted in a significant inhibitory effect on the growth performance and survival rate of P. australis. The growth performance of P. australis, including stem volume and biomass, decreased and its mortality rate increased. Our manipulated experiment suggests a combined treatment approach of moderate inundation, such as 5–10 cm for 20–30 days, and aboveground cutting to manage the overgrowth of P. australis in restored brackish wetlands.

Abstract Citizen science (CS) is the most effective tool for overcoming the limitations of government and/or professional data collection. To compensate for quantitative limitations of the 'Winter Waterbird Census of Korea', we conducted a total of four bird monitoring via CS from 2021 to 2022. To use CS data alongside national data, we studied CS data quality and improvement utilizing (1) digit-based analysis using Benford’s law and (2) comparative analysis with national data. In addition, we performed bird community analysis using CS-specific data, demonstrating the necessity of CS. Neither CS nor the national data adhered to Benford's law. Alpha diversity (number of species and Shannon index) was lower, and total beta diversity was higher for the CS data than national data. Regarding the observed bird community, the number of species per family was similar; however, the number of individuals per family/species differed. We also identified the necessity of CS by confirming the possibility of predicting bird communities using CS-specific data. CS was influenced by various factors, including the perceptions of the survey participants and their level of experience. Therefore, conducting CS after systematic training can facilitate the collection of higher-quality data

Understanding the ecological characteristics of endangered species is essential for their management and conservation. The dark sleeper (Odontobutis obscurus) is a carnivorous freshwater fish that has been designated an endangered species in South Korea because of its highly restricted habitat range and small population size. However, ecological research on prey items for this species remains severely limited globally, posing challenges for establishing conservation measures such as translocation management. In this study, the food sources and feeding strategies of O. obscurus were identified through non-invasive faecal DNA metabarcoding. A total of 24 O. obscurus specimens were collected from Sanyang Stream on Geoje Island, and faecal DNA was amplified using mitochondrial cytochrome c oxidase I (COI) primer. As a result, 13 prey items were identified, comprising fish and benthic invertebrates. Dietary metrics revealed the overall food composition and major food source of O. obscurus, and the Costello method enabled graphical diet analysis, suggesting that O. obscurus is a generalist, feeding on a wide variety of food sources. The food selectivity index suggested that O. obscurus prefers specific prey items, such as genus Misgurnus, Zacco (fish), Radix (gastropod), and Ephemera (mayfly). This molecular method facilitated the diet analysis of an endangered fish species that cannot undergo dissection, providing crucial information for their management, particularly regarding translocation efforts.

Estuary reopening is a means of restoring estuarine habitats, which has recently been implemented in a few developed countries. The regeneration of a brackish zone in the Nakdong River Estuary (NRE), South Korea, were tested through a series of barrage reopening. During the same period, we conducted extensive fish surveys in the upper part of the NRE barrage on a monthly basis from 2017 to 2021, and subsequently determined whether fish populations and communities were affected by the reopening. The results showed that the reopening of the NRE hardly affected the fish community structure, as non-native species such as Erythroculter erythropterus and Lepomis macrochirus maintained their dominance. Still, we discovered that certain euryhaline species are positively affected by estuary reopening, as total 46 Japanese eels (Anguilla japonica) were captured after the reopening, which had not been detected before the reopening. By comparing the size structure of various fish species, we discovered that size distribution of native and migratory species presented more positively skewed pattern after the reopening, while size structure in non-native species remained relatively unchanged normally distributed pattern. Piecewise structural equation modelling revealed that the NRE had become more complex ecosystem, as migratory fish species abundance and biomass started to show a positive correlation with hydraulic factors such as discharge and negative correlation with seasonality after the reopening. We concluded that estuary reopening created some changes in migratory and native freshwater species but such changes were not notably detected in non-native species. Therefore, appropriate sluice operation methodologies, such as considering the migration seasons of migratory species, should be developed. Additionally, human-involved management policies are required to regulate non-native species populations.

In aquatic ecosystem, the food web structure based on composition and abundance of prey species influences the feeding characteristics of predators, resulting in changes to the structure and function of the entire food web. Zooplankton mainly feed on phytoplankton, but the method of analyzing the feed source through visual and microscopic identification of gut contents has limitations in applicable species and the low resolution of the analysis results. In this study, potential vs. eaten food sources of Sinocalanus tenellus, a small and medium-sized copepod species dominant in brackish waters, were analyzed based on phytoplankton operational taxonomic units detected from the habitat’s raw water and treated whole bodies of S. tenellus. The alpha diversity and dominant/subdominant species of each potential and eaten food source were identified, and they were compared across seasons. At the same time, the feeding selectivity index (Ei) was calculated by identifying overlapping species in the potential vs. eaten food source pool. As a result, it was confirmed that not all surrounding potential food sources are fed on by S. tenellus, and that its diet can vary depending on the presence/absence of preferred prey. Metabarcoding techniques is considered to be an effective way to identify fluctuations in major food sources of zooplankton at the genus or species level. If uncertainties such as incomplete species identification as identified from the results of this study are improved through improving of analysis methods such as application of species-specific primers in the future, it will be useful for securing information on the feeding characteristics of small to medium-sized zooplankton.

Ischnura asiatica (Brauer, 1865) is a freshwater damselfly belonging to the family Coenagrionidae that is distributed across most of Korea, primarily in areas with low water flow, such as ponds and wetlands. The complete mitochondrial genome of I. asiatica was sequenced by next-generation sequencing. The circular mitochondrial genome was found to be 15,769 bp long, with of 13 protein-coding, two ribosomal RNA, and 22 transfer RNA genes (GenBank accession no. OM310774). Maximum likelihood, phylogenetic analysis showed that this species clustered with other species belonging to the family Coenagrionidae. This study contributes to the phylogeny of damselflies and other members of the family Coenagrionidae.

Environmental DNA (eDNA) extracted from the gut contents of filter feeders can be used to identify biodiversity in aquatic ecosystems. In this study, we used eDNA from the gut contents of the Asian clam Corbicula fluminea to examine biodiversity within estuarine ecosystem. Field sampling was conducted at three points in the Nakdong River Estuary, which is characterised by closed estuarine features resulting from the presence of an estuarine barrage. The collected C. fluminea samples were dissected to separate the gut contents, and the extracted eDNA was amplified using 18S V9 primer targeting all eukaryote-derived DNA. The amplified DNA was sequenced using a next-generation sequencing (NGS) technique, and a BLASTn search was performed based on the National Centre for Biotechnology Information (NCBI) database for taxa identification. We obtained 23 unique operational taxonomic units (OTUs), including fish (approximately 8.70%), copepods (approximately 17.39%), and green algae (approximately 21.74%), representing a wide range of habitats. Furthermore, 8 out of the 20 families were identified through comparisons with reference data from conventional field surveys, and the OTUs of elusive migratory fish were detected. The results support the application of C. fluminea as an eDNA sampler for supplementary biodiversity monitoring.

Length–weight relations were estimated for 14 fish species sampled from the coastal waters off the Gwangyang Bay in South Korea. The following species were studied: Okamejei kenojei (Müller et Henle, 1841); Muraenesox cinereus (Forsskål, 1775); Thryssa adelae (Rutter, 1897); Thryssa kammalensis (Bleeker, 1849); Tribolodon hakonensis (Günther, 1877); Inimicus japonicus (Cuvier, 1829); Chelidonichthys spinosus (McClelland, 1844); Jaydia lineata (Temminck et Schlegel, 1842); Sillago japonica Temminck et Schlegel, 1843; Pholis nebulosa (Temminck et Schlegel, 1845); Favonigobius gymnauchen (Bleeker, 1860); Pampus echinogaster (Basilewsky, 1855); Cynoglossus joyneri Günther, 1878; Takifugu niphobles (Jordan et Snyder, 1901).The length–weight relation of Thryssa adelae (Rutter, 1897), (Engraulidae) has not been previously reported. The new maximum total length of Thryssa kammalensis (18.0 cm) is now provided. The values of coefficient a ranged from 0.0007 to 0.0218, and the values of exponent b ranged from 2.82 to 3.52.

Climate warming and eutrophication caused by anthropogenic activities strongly affect aquatic ecosystems. Submerged macrophytes usually play a key role in shallow lakes and can maintain a stable clear state. It is extremely important to study the effects of climate warming and eutrophication on the growth of submerged macrophytes in shallow lakes. However, the responses of submerged macrophytes to climate warming and eutrophication are still controversial. Additionally, the understanding of the main pathways impacting submerged macrophytes remains to be clarified. In addition, the influence of seasonality on the growth responses of submerged macrophytes to climate warming and eutrophication requires further elucidation. In this study, we conducted a series of mesocosm experiments with four replicates across four seasons to study the effects of rising temperature and nutrient enrichment on the biomass of two submerged macrophytes, Potamogeton crispus and Elodea canadensis. Our results demonstrated the seasonality and species specificity of plant biomass under the influence of climate warming and eutrophication, as well as the main explanatory factors in each season. Consistent with the seasonal results, the overall results showed that E. canadensis biomass was directly increased by rising temperature rather than by nutrient enrichment. Conversely, the overall results showed that P. crispus biomass was indirectly reduced by phosphorus enrichment via the strengthening of competition among primary producers. Distinct physiological and morphological traits may induce species-specific responses of submerged macrophytes to climate warming and eutrophication, indicating that further research should take interspecies differences into account.

Periphyton plays an important role in lake ecosystems processes, especially at low and intermediate nutrient levels where periphyton contribution to primary production can be similar to or exceed that of phytoplankton. Knowledge of how periphyton responds to key drivers such as climate change and nutrient enrichment is, therefore, crucial. We conducted a series of mesocosm experiments over four seasons to elucidate the responses of periphyton communities to nutrient (low and high, TN-0.33 mg L–1 TP-7.1 μg L–1 and TN-2.40 mg L–1 TP-165 μg L–1, respectively), temperature (ambient, IPCC A2 scenario and A2 + 50%) and plant type (two submerged macrophytes with different morphological structural complexity: Potamogeton crispus and Elodea canadensis, and their corresponding plastic imitations with similar size and structure). We found a noticeable seasonality in the abundance and composition of periphyton. In spring and summer, periphyton abundances were significantly higher in the turbid-high-nutrient state than in the clear-low-nutrient state, and in summer they were notably higher at ambient temperature than in climate scenario A2 and A2 + 50%. In contrast, periphyton abundances in autumn and winter were not influenced by nutrient and temperature, but they were notably higher on plants with a more complex morphological structure than simple ones. The genus composition of periphyton was significantly affected by nutrient–temperature interactions in all seasons and by plant type in winter. Moreover, periphyton functional composition exhibited noticeable seasonal change and responded strongly to nutrient enrichment and temperature rise in spring, summer, and autumn. Our results suggest that the effect of warming on periphyton abundance and composition in the different seasons varied with nutrient state and host plant type in these mesocosms, and similar results may likely be found under field conditions.

Chum salmon (Oncorhyncus keta) is a cold-water species reported to migrate within a wide range of habitats, including Korea, Japan, North America, and Russia, playing important roles in the river–sea nutrient cycle and food web. However, research on this species has not been widely performed in South Korea owing to its geographical location at the southern edge of migration. In this study, we analyzed the spatial distribution and morphological characteristics of chum salmon migrating to South Korea using the length–weight relationship. We also analyzed 3 years of catch, sex ratio, and individual information (total length (cm), weight (kg), n = 4400) from ten rivers (eight in the East coast and two on the South coast) with a total of 17 years of water quality and the distance they traveled (n = 50) using multivariate analysis. As a result, we discovered a trend of less migration in the southern part of South Korea for all individuals migrating to South Korea. Furthermore, the weight ratio of males/females was significantly different (p < 0.05). Based on the length–weight relationship analysis, the a and b values were between 0.0011 and 0.038 and 2.65 and 3.49, respectively. In the correlation analysis, catch is negatively correlated with distance traveled and temperature (p < 0.05), and positively correlated with pH, dissolved oxygen, distance, and female ratio (p < 0.05). This is possibly the result of differences in water quality during early life stages or the presence of an estuarine barrage at the mouth of the Nakdong River. This research may be used as fundamental distribution and morphological variations of chum salmon in South Korea.

Tangential-firing boilers develop large swirling fireballs by using pulverized coal and air from the corners of the burner zone. During operation, however, the boiler may experience an uneven air supply between corners; this deforms the fireball, raising various issues concerning performance and structural safety. This study investigated the characteristic boiler performance and the role of burner tilting in a 500 MWe boiler with secondary air (SA) in two corners that are up to 1.9 times larger than those in the other corners. Computational fluid dynamics simulations with advanced coal combustion sub-models were employed with the following two sets of cases: (i) six cases of actual operation to validate the modeling and (ii) sixteen cases for the parametric study of SA flow ratio and burner tilt between −15° and +26°. The results showed that the uneven SA supply deteriorated the boiler performance in various aspects and the burner tilt can be used to alleviate its impact. With a larger SA supply from the left wind box, the mass flow, heat absorption, and O2 concentration were larger in the right half of the heat exchanger sections owing to the rotating flow. The corresponding imbalance in the reaction stoichiometry increased the peak temperature entering the tube bundles by up to 60 °C and NO emissions by 6.7% as compared with normal operations. The wall heat absorption was up to 19% larger on the right and front walls. The high burner tilt of +26° helped alleviate the impact of uneven SA supply on the heat distribution and uniformity of the flow pattern and temperature, whereas a +15° burner tilt was the least favorable.

The complete mitochondrial genome of Stictochironomus akizukii (Tokunaga) was sequenced. The circular mitochondrial genome is 15,052 bp and consists of 13 protein-coding, 3 ribosomal RNAs, and 22 transfer RNA genes (GenBank accession no. MT185679). Results of maximum likelihood analysis showed that this species clustered with other species of the family Chironomidae. This study will contribute to the phylogenetics of genus Stictochironomus and the other genera of Chironomidae.

The gut bacterial communities of copepods can affect metabolic processes, and consequently, their activity can be related to the release of organic substances to the environment. Hence, they are important for organic matter cycling in marine coast food webs. However, information regarding the variation in gut bacterial communities based on copepod species and environmental variations is limited. We analysed the differences in gut bacterial communities from dominant copepod species, i.e., Acartia hudsonica, Sinocalanus tenellus, and Pseudodiaptomus inopinus, in a brackish reservoir. The core bacteria among the copepod species and locations consisted of the following main operational taxonomic units (OTUs): Novosphingobium capsulatum and the family Rhodobacteraceae belonging to Alphaproteobacteria, which is abundant in seawater and freshwater aquatic ecosystems as a zooplankton-associated bacterial community. The bacterial community composition of each copepod (except the core species) showed high variability. The bacterial community diversity differed depending on the copepod species and the sites’ environmental conditions, especially salinity, e.g., compositional variations in the bacterial community of P. inopinus were high at sites with low salinity. Therefore, the gut bacterial community of each copepod species responds differently to the environment.

For renewable electricity production, biomass can fully displace coal in an existing power plant with some equipment modifications. Recently, a 125 MWe power plant burning mainly anthracite in Korea was retrofitted for dedicated wood pellet combustion with a change of boiler configuration from arch firing to wall firing. However, this boiler suffers from operational problems caused by high unburned carbon (UBC) contents in the bottom ash. This study comprises an investigation of some methods to reduce the UBC release while achieving lower NOx emissions. The computational fluid dynamics approach was established and validated for typical operating data. Subsequently, it was applied to elucidate the particle combustion and flow characteristics leading to the high UBC content and to evaluate the operating variables for improving the boiler performance. It was found that the high UBC content in the bottom ash was a combined effect of the poor fuel grindability and low gas velocity in the wide burner zone originating from the arch-firing boiler. This prevented the operation with deeper air staging for lower NOx emissions. Reducing the particle size to x emissions with deeper air staging while increasing the boiler efficiency.

The complete mitochondrial genome of Favonigobius gymnauchen was sequenced. The circular mitochondrial genome is 16,480 bp and consists of 13 protein-coding, 2 ribosomal RNAs, and 13 transfer RNA genes (GenBank accession no. MN194589). Results of maximum likelihood analysis showed that this species clustered with other species of the family Gobbidae. This study will contribute to the phylogenetics of genus Favonigobius and the other genera of Gobiidae.

We investigated the influence of summer rainfall on Pectinatella magnifica colonies in lotic ecosystems. Of the examined substrate materials, branches and aquatic macrophytes supported more colonies of P. magnifica than that by stones or artificial materials. The influence of rainfall on P. magnifica colonies differed in accordance with the type of substrate material at each study site. In the Geum River, little difference was noted in the number of P. magnifica colonies on branches before (mean ± SE, 24 ± 7.3 individuals) and after rainfall (20 ± 8.4 ind.); other substrate types supported fewer colonies of P. magnifica after rainfall. In contrast, in the Miryang River, rainfall had minimal effect on the number of P. magnifica colonies supported by macrophytes (13 ± 3.8 and 12 ± 4.3 ind., respectively). Artificial material was more abundant in the Banbyeon Stream where it was able to support more colonies of P. magnifica. We found that the structure of different substrates sustains P. magnifica following rainfall. In the Miryang River, free-floating and submerged plants with a relatively heterogeneous substrate surface were the dominant macrophytes, whereas in the Geum River, simple macrophytes (i.e., emergent plants) were dominant. Therefore, we conclude that the substrate type on which P. magnifica grows plays an important role in resisting physical disturbances such as rainfall.

We designed an experiment to analyze the gut content of Rotifera based on DNA barcoding and tested it on Asplanchna sp. in order to ensure that the DNA extracted from the rotifer species is from the food sources within the gut. We selected ethanol fixation (60%) to minimize the inflow effects of treated chemicals, and commercial bleach (the final concentration of 2.5%, for 210 s) to eliminate the extracellular DNA without damage to the lorica. Rotifers have different lorica structures and thicknesses. Therefore, we chose a pretreatment method based on Asplanchna sp., which is known to have weak durability. When we used the determined method on a reservoir water sample, we confirmed that the DNA fragments of Chlorophyceae, Diatomea, Cyanobacteria, and Ciliophora were removed. Given this result, Diatomea and cyanobacteria, detected from Asplanchna, can be considered as gut contents. However, bacteria were not removed by bleach, thus there was still insufficient information. Since the results of applying commercial bleach to rotifer species confirmed that pretreatment worked effectively for some species of rotifers food sources, in further studies, it is believed to be applicable to the gut contents analysis of more diverse rotifers species and better DNA analysis techniques by supplementing more rigorous limitations.

We conducted a distributional survey of Pectinatella magnifica, an invasive species, in the Geum River and the Nakdong River from July 12 to July 25, 2014. The spacing between the study sites was 10 km along the main channels for the Geum River (n = 12, 120 km) and the Nakdong River (n = 38, 380 km) from the estuarine barrage to upper part of main channel. Pectinatella magnifica was detected along the riparian zone (within 100 m) at each of the study sites. Presence rate of P. magnifica in Geum River and Nakdong River was 25% and 32.6%, respectively. The colony number of P. magnifica at Geum River (9.5 ± 3.1 colony/m, n = 3) was over 94 fold higher than that in the Nakdong River (0.1 ± 0.1 colony/m, n = 16). The Total length distribution of P. magnifica had a truncated bell shape at each rivers (mean length: 14.0 ± 1.2 cm for Geum River (n = 32), and 16.8 ± 1.4 cm for Nakdong River (n = 52)). These findings could provide basic information regarding the distribution pattern of P. magnifica in a new invasion area.

The nonlinearity and complexity of coastal ecosystems often cause difficulties when analyzing spatial and temporal patterns of ecological traits. Environmental DNA (eDNA) monitoring has provided an alternative to overcoming the aforementioned issues associated with classical monitoring. We determined aquatic community taxonomic composition using eDNA based on a meta-barcoding approach that characterizes the general ecological features in the Gwangyang Bay coastal ecosystem. We selected the V9 region of the 18S rDNA gene (18S V9), primarily because of its broad range among eukaryotes. Our results produced more detailed spatial patterns in the study area previously categorized (inner bay, main channel of the bay and outer bay) by Kim et al. (2019). Specifically, the outer bay zone was clearly identified by CCA using genus-level identification of aquatic organisms based on meta-barcoding data. We also found significant relationships between environmental factors. Therefore, eDNA monitoring based on meta-barcoding approach holds great potential as a complemental monitoring tool to identify spatial taxonomic distribution patterns in coastal areas.

Our study focuses on methodological comparison of plankton community composition in relation to ecological monitoring and assessment with data sampling. Recently, along with the advancement of monitoring techniques, metabarcoding has been widely used in the context of environmental DNA (eDNA). We examine the applicability of eDNA metabarcoding for effective monitoring and assessment of community composition, compared with conventional observation using microscopic identification in a coastal ecosystem, Gwangynag Bay in South Korea. Our analysis is based primarily on two surveys at a total of 15 study sites in early and late summer (June and September) of the year 2018. The results of our study demonstrate the similarity and dissimilarity of biological communities in composition, richness and diversity between eDNA metabarcoding and conventional microscopic identification. It is found that, overall, eDNA metabarcoding appears to provide a wider variety of species composition, while conventional microscopic identification depicts more distinct plankton communities in sites. Finally, we suggest that eDNA metabarcoding is a practically useful method and can be potentially considered as a valuable alternative for biological monitoring and diversity assessments.

The use of separated overfire air (SOFA) has become a standard technique of air staging for NOx reduction in the coal-fired boiler and can also be applied to existing boilers by retrofit. This study was to optimize the air distribution for the proposed SOFA installation in a 500 MWe tangential-firing boiler that has 20 identical units in Korea. Using computational fluid dynamics (CFD) incorporating advanced coal combustion submodels, the reference case was established in good agreement with the design data, and different flow ratios of burner secondary air, close-coupled OFA (CCOFA), and SOFA were evaluated. Increasing the total OFA ratio effectively suppressed NO formation within the burner zone but had a negative impact on the boiler performance. With moderate air staging, NO reduction became active between the CCOFA and SOFA levels and, therefore, the OFA distribution could be optimized for the overall boiler performance. For total OFA ratios of 25% and 30% with respective burner zone stoichiometric ratios of 0.847 and 0.791, increasing the SOFA ratio to 15% and 20%, respectively, was ideal for decreasing the unburned carbon release and ash slagging as well as NO emission. Too high or low SOFA ratios rapidly increased the unburned carbon because of inefficient mixing between the strong air jets and char particles. Based on these ideal cases, the actual air distribution can be adjusted depending on the coal properties such as the ash slagging propensity.

Vitellogenesis is a pivotal reproductive process of the yolk formation in crustaceans. Vitellogenin (VTG) is the precursor of main yolk proteins and synthesized by endogenous estrogens. The intertidal mud crab (Macrophthalmus japonicus) inhabits sediment and is a good indicator for assessing polluted benthic environments. The purpose of this study was to identify potential responses of M. japonicus VTG under environmental stresses caused by chemical pollutants, such as 1, 10, and 30 µg L−1 concentrations in di(2-ethylhexyl) phthalate (DEHP), bisphenol A (BPA) and irgarol. We characterized the M. japonicus VTG gene and analyzed the transcriptional expression of VTG mRNA in M. japonicus exposed to various chemicals and exposure periods. A phylogenetic analysis revealed that the M. japonicus VTG clustered closely with Eriocheir sinensis (Chinese mitten crab) VTG, in contrast with another clade that included the VTG ortholog of other crabs. The basal level of VTG expression was the highest in the hepatopancreas and ovaries, and tissues. VTG expression significantly increased in the ovaries and hepatopancreas after 24 h exposure to DEHP. Increased responses of VTG transcripts were found in M. japonicus exposed to DEHP and BPA for 96 h; however, VTG expression decreased in both tissues after irgarol exposure. After an exposure of 7 d, VTG expression significantly increased in the ovaries and hepatopancreas for all concentrations of all chemicals. These results suggest that the crustacean embryogenesis and endocrine processes are impaired by the environmental chemical pollutants DEHP, BPA, and irgarol.

The complete mitochondrial genome of the freshwater bryozoan Pectinatella magnifica was sequenced. The circular mitochondrial genome is 17,539 bp and consists of 13 protein-coding, two ribosomal RNA, and 22 transfer RNA genes (GenBank accession no. MG546680). The Bayesian comparative analysis of molecular evolution rates revealed no acceleration of the mitochondrial DNA (mtDNA) evolution of P. magnifica. Results of maximum likelihood analysis showed that this species clustered with other species of the phylum Bryozoa.