Characteristics and Trends of Pediatric Trauma in Jeju Island, South Korea: A Community Level Serial Cross-sectional study.

Objective: This study aimed to investigate the characteristics and epidemiological trends of pediatric injuries among patients visiting emergency departments (EDs) on Jeju Island. Method: Employing a community-level serial cross-sectional analysis, we targeted pediatric patients aged 18 years or younger who visited EDs for injuries over a ten-year period. The data, sourced from the Jeju Injury Surveillance System (JISS), facilitated a comprehensive examination of injury characteristics and epidemiological trends. This included an evaluation of the annual incidence and overall trends in pediatric injury cases. Results: The study found toddlers (42.5% of cases) to be the most frequently injured age group. Males were more prone to injuries, with a male-to-female ratio of 1.7:1. Injuries among visitors accounted for 17.3% of cases, with a seasonal spike in Summer, evenings and weekends. Most incidents occurred at home, predominantly accidental in nature, with adolescents more likely to require EMS services. The common mechanisms of injuries were blunt force (49.2%), slips/falls (22.0%), and motor vehicle collisions (13.2%), leading to bruises, cuts, and sprains. Over the decade, a general increase in pediatric injuries was observed. Accidental injuries initially surged but later stabilized, while self-harm/suicide and assault/violence injuries showed a concerning upward trend. Age-specific analysis revealed increasing trends in infants and adolescents. Conclusion: The study underscores the crucial need for targeted injury prevention and resource allocation strategies, particularly for high-risk groups and times, to effectively mitigate pediatric trauma on Jeju Island.

Retrospective Study of the Prevalence and Associated Factors of Gallbladder Polyps among Residents of Two Korean Cities.

Background/Aims: Well-known risk factors for gallbladder polyps include metabolic syndrome, age, and dyslipidemia. Jeju Island is approximately 80 km from the Korean peninsula and is divided into two administrative regions (Jeju City and Seogwipo City), with Mount Halla intervening in the center. Jeju City has higher employment and birth rates than Seogwipo City. Age and alcohol consumption differ between the two regions, and these factors may affect the prevalence of gallbladder polyps (GBPs). Therefore, we investigated the prevalence of GBPs and compared various factors, including alcohol consumption habits and age, associated with GBPs among residents in the two regions. Methods: This study included 21,734 residents who visited the Health Screening and Promotion Center of Jeju National University Hospital between January 2009 and December 2019. We investigated the prevalence and associated factors of GBPs among residents of Jeju City and Seogwipo City. Results: The prevalence of GBPs in Jeju City and Seogwipo City was 9.8% and 8.9% (p = 0.043), respectively. The mean age and rate of high-risk alcohol intake were higher in Seogwipo City. The mean body mass index and levels of fasting blood glucose, total cholesterol, low-density lipoprotein cholesterol, aspartate aminotransferase, gamma-glutamyl transferase, and alkaline phosphatase were lower in Jeju City. Conclusions: This study demonstrated a significant difference in GBP prevalence between the two regions of Jeju Island. Age and alcohol consumption might contribute to this difference; however, further prospective cohort studies are warranted to confirm our findings.

Monitoring and evaluation of provincial classical swine fever immunization implementation with an E2 subunit vaccine in Jeju Island, South Korea.

Purpose: Accidental vaccination with a live attenuated low-virulence strain of Miyagi (LOM) vaccine led to the reemergence of classical swine fever virus (CSFV) in Jeju province, South Korea in 2014. To control the continual outbreaks of LOM-derived CSFV, the provincial government launched a provincial mass vaccination project using a CSF-E2 subunit vaccine. We conducted this study to assess the herd immunity level and outcomes of E2 vaccine-based immunization in breeding and growing herds on Jeju Island during 2020-2021. Materials and Methods: A large-scale vaccination trial using the Bayovac CSF-E2 vaccine investigated its efficacy in breeding and growing herds under farm application conditions (10 CSFV-affected and three CSFV-naïve swine farms). Results: The level of herd immunity in each farm was classified into three (S1-S3) and six (G1-G6) profiles in breeding and growing herds, respectively. Immunity monitoring revealed a remarkable improvement in the herd immunity status in all farms. The majority (10/13) of farms, including CSFV-free farms, showed the S1G1 immunity profile in 2021, indicating the appropriate implementation of the advised vaccination regime. Moreover, there were significant decreases in Erns seropositivity from 100% to 50% and 25.9% to 4.3% at farm and pig levels, respectively. In particular, all farms were confirmed as CSFV free in the growing-finishing herds. Conclusion: Our large-scale trial demonstrated the effectiveness of the E2 subunit vaccine in establishing herd immunity stabilization and eliminating CSFV circulation in the affected farms and highlighted the need for a provincial vaccination policy to regain the CSF-free status on Jeju Island.

Identification and Antimicrobial Susceptibilities for Patients with Non-tuberculous Mycobacteria Infection in Jeju Island: Single-Center Retrospective Study.

BACKGROUND: The distribution of species and characteristics of non-tuberculous mycobacteria (NTM) differ, and surveillance data for changes in antimicrobial susceptibilities of NTM is insufficient. This study analyzed the changes in antimicrobial susceptibility trends across NTM species and assessed the appropriateness of empirical antimicrobial drugs for NTM. MATERIALS AND METHODS: We retrospectively analyzed the clinical characteristics, including demographics, distribution of NTM species, antimicrobial drug susceptibilities, and outcomes, at a teaching hospital in Jeju Island from 2009 - 2022. RESULTS: Overall, 342 patients were included in the analysis; 93.0% were classified into the pulmonary group (PG) and 7.0% into the extrapulmonary group (EPG). The isolation rate of Mycobacterium avium was significantly higher in PG (36.8% vs. 0%, P = 0.001), while that of Mycobacterium fortuitum was significantly higher in EPG (4.5% vs. 31.3%, P = 0.001). The antimicrobial susceptibility rate is higher against clarithromycin (89.9%) and amikacin (83.3%) and lower against rifampin (54.7%) and ethambutol (28.1%). The susceptibility rate to clarithromycin was over 80%, but those to rifampin and ethambutol showed decreasing annual trends. Of the 162 patients who received empirical antimicrobial therapy, actual antimicrobial susceptibility rates were high (90.1%) using empirical macrolide, and relatively low using ethambutol and rifampin (28.0% and 58.8%, respectively). CONCLUSION: This is the first study of analysis of the distribution, baseline characteristics, and antimicrobial susceptibility of isolated NTM species in pulmonary and extrapulmonary patients in Jeju Island over 10 years. Policies that continuously monitor changes in susceptibility rate are required to ensure effective treatment strategies.

Genomic surveillance of genes encoding the SARS-CoV-2 spike protein to monitor for emerging variants on Jeju Island, Republic of Korea.

Introduction: The severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) pandemic has been fueled by new variants emerging from circulating strains. Here, we report results from a genomic surveillance study of SARS-CoV-2 on Jeju Island, Republic of Korea, from February 2021 to September 2022. Methods: A total of 3,585 SARS-CoV-2 positive samples were analyzed by Sanger sequencing of the gene encoding the spike protein before performing phylogenetic analyses. Results: We found that the Alpha variant (B.1.1.7) was dominant in May 2021 before being replaced by the Delta variant (B.1.617.2) in July 2021, which was dominant until December 2021 before being replaced by the Omicron variant. Mutations in the spike protein, including N440K and G446S, have been proposed to contribute to immune evasion, accelerating the spread of Omicron variants. Discussion: Our results from Juju Island, Republic of Korea, are consistent with and contribute to global surveillance efforts crucial for identifying new variants of concern of SARS-CoV-2 and for monitoring the transmission dynamics and characteristics of known strains.

The Liverwort and Hornwort Flora of Jeju Island, Republic of Korea: A Volcanic Island with a Unique Mixture of Subtropical, Temperate, Boreal, and Arctomontane Taxa.

Jeju Island, due to its position at the southern tip of the Korean Peninsula in Northeast Asia, is a on the unique enclave of the many southern elements in the area and features a mixture of subtropical, temperate, boreal, and arctomontane taxa. Among the arctomontane species recorded in this study was Anthelia juratzkana; among the temperate species was Dactyloradula brunnea, and subtropical species were Cavicularia densa, Pallavicinia subciliata, Wiesnerella denudata, and Megaceros flagellaris. A valuable species as first recorded for the Jeju Island is Cryptocoleopsis imbricata. The distribution patterns of these species suggest that the flora of Jeju Island is a meeting place between boreal and subtropical floras. We recorded 222 taxa belonging to 45 families, 80 genera, 209 species, 9 subspecies, and 4 varieties. Among these, 86 species are reported as new to the flora of Jeju Island. A checklist based on a study of 1697 specimens is also provided.

Inhibiting bacterial biofilm formation by stimulating c-di-GMP regulation using citrus peel extract from Jeju Island.

Biofilms consist of single or multiple species of bacteria embedded in extracellular polymeric substances (EPSs), which affect the increase in antibiotic resistance by restricting the transport of antibiotics to the bacterial cells. An alternative approach to treatment with antimicrobial agents is using biofilm inhibitors that regulate biofilm development without inhibiting bacterial growth. In this study, we found that citrus peel extract from Jeju Island (CPEJ) can inhibit bacterial biofilm formation. According to the results, CPEJ concentration-dependently reduces biofilm formation without affecting bacterial growth. Additionally, CPEJ decreased the production of extracellular polymeric substances but increased bacterial swarming motility. These results led to the hypothesis that CPEJ can reduce intracellular bis-(3'-5')-cyclic dimeric guanosine monophosphate (c-di-GMP) concentration. The results showed that CPEJ significantly reduced the c-di-GMP level through increased phosphodiesterase activity. Altogether, these findings suggest that CPEJ as a biofilm inhibitor has new potential for pharmacological (e.g. drug and medication) and industrial applications (e.g. ship hulls, water pipes, and membrane processes biofouling control).

Biogeographic origin and genetic characteristics of the peopling of Jeju Island based on lineage markers.

BACKGROUND: Jeju Island is the largest island of South Korea, located southwest far from the mainland of Korea, and has a unique history and its own cultures that are distinguished from those of the other regions of the Korean mainland. However, the Jeju population has not been deeply investigated to date to understand their genetic structure, which may reflect their historical and geographical background. OBJECTIVE: To identify the genetic characteristics and biogeographic origin of people of Jeju Island based on the statistical analysis of genetic data using lineage markers. METHODS: 17 Y-STRs data for 615 unrelated males and mitochondrial DNA haplogroup data for 799 unrelated individuals residing on Jeju Island were generated, and analyzed to investigate genetic diversity and genetic characteristics using statistical methods including pairwise Fst or Rst, Analysis of molecular variance (AMOVA) and Multidimensional scaling (MDS). RESULTS: For male individuals of Jeju Island, unique genetic characteristics were observed in the analysis of Y-STRs, including low haplotype diversity, strong association with surnames, genetic difference from other regions of Korea, and common genetic variation of the Y-STR loci known to be predominant in Northern populations, such as Mongolians. Statistical analysis of the mitochondrial DNA haplogroups also revealed similar results that showed low haplogroup diversity and high frequency of haplogroup Y prevalent mostly in ethnic populations around the Sea of Okhotsk in Northeastern Asia. All these results suggest that Jeju Island is genetically distinct from other regions of Korea, possibly being a subpopulation in Korea, and related closely to Northern Asian populations. CONCLUSION: The findings in the genetic approach could support understanding of the historical background of Jeju Island that is consistent with evidence from other multidisciplinary studies.

Field evaluation of the safety and immunogenicity of a classical swine fever virus E2 subunit vaccine in breeding and nursery animals on Jeju Island, South Korea.

Purpose: Classical swine fever (CSF) reemerged on CSF-free Jeju Island where vaccination is not practiced by the unintentional injection of a live attenuated vaccine (modified live attenuated vaccines-low-virulence Miyagi [MLV-LOM]) in 2014. Since the Jeju provincial authority is considering adopting a voluntary immunization policy using a CSF-E2 subunit vaccine to combat LOM-derived CSF endemic, this study aimed to evaluate in Jeju herds. Materials and Methods: Two vaccination trials using the Bayovac CSF-E2 vaccine licensed for use in South Korea assessed the safety and humoral immunity of the CSF-E2 vaccine in breeding (trial 1) and nursery animals (trial 2) under farm application conditions. Results: Neither local nor systemic (including reproductive) adverse effects were objectively observed in pregnant sows and young piglets following a respective vaccination regime at pregnancy or weaning, respectively. Trial 1 showed that sows immunized with the CSF-E2 vaccine possessed high and consistent E2-specific and neutralizing antibody levels. The CSF-E2 vaccine-immunized pregnant sows subsequently conferred appropriate and steady passive immunity to their offspring. In trial 2, a double immunization scheme of the CSF-E2 vaccine in piglets at 40 and 60 days of age could elicit a consistent and long-lasting adequate antibody response. Additionally, the two trials detected no Erns-specific antibody responses, indicating that CSF-E2 vaccine can differentiate infected from vaccinated animals (DIVA). Conclusion: Our trial data collectively provide invaluable information on applying the CSF-E2 subunit vaccine to circumvent the possible drawbacks associated with the MLV-LOM concerning the safety, efficacy, and DIVA, in the LOM-endemic field farms and contribute to advanced CSF eradication on Jeju Island.

Possible link between derelict fishing gear and sea turtle strandings in coastal areas.

Ghost fishing via a derelict fishing gear (DFG) is a critical threat to marine organisms. To explore the effect of DFG on sea turtle strandings, the DFG distribution was compared at two sites on Jeju Island (South Korea) with a contrasting number of strandings. Coastal areas in northern Jeju Island were surveyed during dives with scuba equipment, and the DFG from two sites, Gwideok-ri and Sinchang-ri was collected and compared in terms of quantity and size of the items. Fishing line was more common, longer, and thicker in Gwideok-ri than in Sinchang-ri, while other types of DFG did not differ between the two sites. In addition, necropsies on two loggerhead sea turtles discovered on Jeju Island found fishing lines with fishing hooks in the oral cavity of both carcasses. This suggests that derelict recreational fishing lines may pose a significant threat to sea turtles in coastal areas.

Integrated application of a Bayesian mixing model, numerical model, and environmental tracers to characterize groundwater recharge sources in a mountainous area.

In this study, the combined use of a Bayesian mixing model (BMM), numerical model (random walk particle tracking-RWPT), and environmental tracers (δ18O-δD, 3H, and CFC) was applied to elucidate the probabilistic contribution of the recharge sources, flow path, and residence time of groundwater across the mountainous area of Jeju Island, South Korea. Especially, the BMM ability to estimate the variable recharge contributions to the aquifer by different elevations and seasons was investigated. The δ18O-δD isotopes showed that groundwater in the study area was primarily fed by precipitation during the wet season, and the BMM estimated that wet season recharge contributed to approximately 64% of the total. The BMM-based probabilistic estimation of recharge sources revealed a mixed contribution of source waters from different elevations. A notable difference in recharge flow path was observed between highland (>450 masl) and lowland (<400 masl) wells, where the inflow of source water from the regional flow was dominant in the former and both regional and local recharges served as significant groundwater sources in the latter. Evidence from age tracers (3H and CFC-12) also supported different recharge mechanisms between highland and lowland wells. A reasonable match between the BMM- and RWPT-derived recharge contributions (RMSE 0.02-0.06) was achieved within the uncertainty ranges, with RWPT being particularly useful for capturing different flow paths between highland and lowland wells. The dynamics revealed here provide important information for establishing an improved and informed groundwater management plan for the mountainous area of Jeju Island. Ultimately, this study highlights the advantageous integrated analysis of BMM, RWPT, and environmental tracer analyses to enhance the reliability of recharge area estimation and increase the collective understanding of complex hydrogeological systems in mountainous areas.

Pathogenicity of a novel classical swine fever LOM vaccine-derived virus isolated on Jeju Island, South Korea.

BACKGROUND: Reemergent local outbreaks of classical swine fever (CSF) occurred simultaneously in multiple pig farms on CSF-free Jeju Island, South Korea, in 2014 because of inadvertent injection of a commercial CSF (LOM) vaccine into pregnant sows. The LOM virus has since spread across the island and has become endemic in Jeju herds, raising concern about possible reversion to the virulence of the LOM vaccine. We previously isolated LOM-derived field CSF virus (CSFV) strains with unique insertion-deletion (INDEL) mutations in the 3'-untranslated region (UTR), designated LOM-derived Jeju 3'-UTR INDEL variants, from CSF-recurrent swine farms on Jeju Island in 2019. METHODS: The present study conducted animal experiments to investigate whether a 2019 emergent LOM 3'-UTR INDEL variant, KNU-1905, has reverted to a pathogenic form in conventional pigs (n = 10). RESULTS: Experimental animal infection showed that pigs inoculated with the commercial LOM vaccine strain developed no adverse effects compared to the sham-infected pigs. However, KNU-1905 displayed pathogenic characteristics in pigs, including clinical symptoms (e.g., lethargy, conjunctivitis, nasal discharge, and diarrhoea), weight loss, and gross lesions. Moreover, viremia, virus shedding in faeces and nasal fluids, and viral loads in various tissues of all the KNU-1905-infected pigs were highly significant, in contrast to those of the LOM-infected group in which CSFV RNA was detected only in the serum, nasal, and tonsil samples of one identical pig. CONCLUSIONS: Overall, the LOM-derived field isolate with molecular variations induced clinical adverse events in pigs, which commonly shed considerable amounts of CSFV. This study provides evidence that the genetic evolution of the LOM-derived CSFV circulating on Jeju Island might have allowed the LOM vaccine to recover its primary prototype and that these variants might have induced chronic or persistent infection in pigs that can shed CSFV in field farms leading to a risk of transmission among pigs or farms in this former CSF-free region.

Molecular Evidence Reveals the Sympatric Distribution of Cervus nippon yakushimae and Cervus nippon taiouanus on Jeju Island, South Korea.

Non-native species threaten native ecosystems and species, particularly on islands where rates of endemism and vulnerability to threats are high. Understanding species invasion will aid in providing insights into ecological and evolutionary processes. To identify the non-native sika deer (Cervus nippon) population in Jeju, South Korea, and their phylogenetic affinities, we collected tissue samples from roadkill and the World Natural Heritage Headquarters in Jeju. Mitochondrial DNA cytochrome B (CytB) gene sequences were analyzed to determine two distinct CytB haplotypes. Phylogenetic analysis using maximum likelihood tree revealed two haplotypes of CytB clustered into two different groups representing two subspecies: C. n. yakushimae, native to Japan, and C. n. taiouanus, native to Taiwan. The tentative divergence time between the two subspecies was estimated at 1.81 million years. Our study confirmed that the two subspecies of sika deer are sympatric in the natural ecosystem of Jeju Island. This study provides valuable information to help government and conservation agencies understand alien species and determine control policies for conserving native biodiversity in South Korea.

Onyx disparamphis sp. n. (Nematoda, Desmodorida) from South Korea with a taxonomic review of the genus.

A new free-living marine nematode Onyx disparamphis sp. n. (Nematoda, Desmodorida) is described from sandy littoral of Jeju Island, South Korea. The new species differs from all other Onyx species by the unusual amphideal fovea morphology in males (elongated loop). O. disparamphis relates to O. balochinensis, and O. brevispiculatum by having simple non-double terminal pharyngeal bulb and relatively small and straight, non-sigmoid supplementary organs, but differs from them by smaller body length, shorter cephalic setae, smaller terminal pharyngeal bulb, smaller spicules, number of supplementary organs and tail shape expressed as ratio tail length/anal diameter. The genus Onyx is revised with updated genus diagnosis, and an annotated list of 23 valid species is presented. Onyx ferox is considered species inquirenda because the species is known only from a sole immature female specimen, while within Onyx, the males provide the most important distinguishing characters such as enlarged and complicated amphids, supplementary organs and copulatory spicules. For species identification, a pictorial key consisting of illustrations of simplified icons of male heads and posterior body sections, as well as a table of the most important morphometric and numerical characters are provided. Geographical distribution and habitat specifity of Onyx species is analysed briefly.

DNA barcoding and morphological identification of spiny lobsters in South Korean waters: a new record of Panulirus longipes and Panulirus homarus homarus.

To date, 19 species of spiny lobsters from the genus Panulirus have been discovered, of which only P. japonicus, P. penicilatus, P. stimpsoni, and P. versicolor have been documented in South Korean waters. In this study, we aimed to identify and update the current list of spiny lobster species that inhabit South Korean waters based on the morphological features and the phylogenetic profile of cytochrome oxidase I (COI) of mitochondrial DNA (mtDNA). Spiny lobsters were collected from the southern and eastern coasts of Jeju Island, South Korea. Phylogenetic analyses were performed using neighbor-joining (NJ), maximum likelihood (ML), and Bayesian inference (BI) methods. The ML tree was used to determine the spiny lobster lineages, thereby clustering the 17 specimens collected in this study into clades A, B, C, and D, which were reciprocally monophyletic with P. japonicus, P. homarus homarus, P. longipes, and P. stimpsoni, respectively. These clades were also supported by morphological examinations. Interestingly, morphological variations, including the connected pleural and transverse groove at the third abdominal somite, were observed in four specimens that were genetically confirmed as P. japonicus. This finding is novel within the P. japonicus taxonomical reports. Additionally, this study updates the documentation of spiny lobsters inhabiting South Korean waters as P. longipes and P. homarus homarus were recorded for the first time in this region.

Complete chloroplast genome of Sphagnum subsecundum Nees from Korea.

We determined the complete chloroplast genome sequence of the peatmoss Sphagnum subsecundum Nees from Mt. Halla in Korea. The total size of the chloroplast genome was 140,136 bp, and it consisted of a large single-copy region (LSC) of 98,064 bp, a small single-copy region (SSC) of 21,388 bp, and two copies of inverted repeat (IRa and IRb) regions of 10,342 bp each. The genome encoded a set of 130 genes, comprising 85 protein-coding genes, 37 tRNA genes, and 8 rRNA genes. This species formed a monophyletic clade with S. orientale and S. lenese as the result of ML phylogenetic analysis based on whole gemone sequence of 15 species including one outgroup species.

Nocardioides donggukensis sp. nov. and Hyunsoonleella aquatilis sp. nov., isolated from Jeongbang Waterfall on Jeju Island.

Two bacterial strains, designated MJB4T and SJ7T, were isolated from water samples collected from Jeongbang Falls on Jeju Island, Republic of Korea. Phylogenetic analysis of 16S rRNA gene sequences indicated that the two strains belonged to the genera Nocardioides and Hyunsoonleella, owing to their high similarities to Nocardioides jensenii DSM 29641T (97.5 %) and Hyunsoonleella rubra FA042 T (96.3 %), respectively. These values are much lower than the gold standard for bacterial species (98.7 %). The average nucleotide identity values between strains MJB4T, SJ7T and the reference strains, Nocardioides jensenii DSM 29641T, Nocardioides daejeonensis MJ31T and Hyunsoonleella flava T58T were 77.2, 75.9 and 75.4 %, respectively. Strains MJB4T and SJ7T and the type strains of the species involved in system incidence have average nucleotide identity and average amino acid threshold values of 60.1-82.6 % for the species boundary (95-96 %), which confirms that strains MJB4T and SJ7T represent two new species of genus Nocardioides and Hyunsoonleella, respectively. Based on phylogenetic and phenotypic data, strains MJB4T and SJ7T are considered to represent novel species of the genus Nocardioides and Hyunsoonleella, respectively, for which the names Nocardioides donggukensis sp. nov. (type strain MJB4T=KACC 21724T=NBRC 114402T) and Hyunsoonleella aquatilis sp. nov., (type strain SJ7T=KACC 21715T=NBRC 114486T) have been proposed.

Pontibacter aquaedesilientis sp. nov., isolated from Jeongbang Waterfall, Jeju Island.

A red-pigmented, aerobic, motile by gliding, pleomorphic to long-rods and divided by budding bacterium, Gram-stain negative bacterium, designated JH31T, was isolated from stream water of Jeongbang Waterfall, famous feature of Jeju Island, Republic of Korea. The cells grew at 9-40 °C (optimum, 28-30 °C), at pH 5.0-10.0 (pH 6.5-7.5) and with 0-6% NaCl (0% NaCl). Phylogenetic analysis based on 16S rRNA gene sequences revealed that strain JH31T forms a lineage within the family Hymenobacteriaceae and clusters with its closest related species Pontibacter virorsus KCTC 42941T (98.1%), Pontibacter salisaro KACC 16885T (98.0%), Pontibacter amylolyticus JCM 19653T (97.2%), Pontibacter ramchanderi KACC 17384T (97.2%) and Pontibacter lucknowensis DM9T (96.4%). Strain JH31T produced carotenoid-type pigments but no flexirubin-type pigments. The genome was 4117105 bp long with 18 contigs and 3509 protein-coding genes. The DNA G+C content was 49.7 mol%. The digital DNA-DNA hybridization and average nucleotide identity values between the genome sequence of strain JH31T and its closely related reference strains were less than 19 and 72%, respectively. The draft genome of strain JH31T contained vital gene clusters involved in resistance against various metals, antibiotics, toxic compounds and radiation. The respiratory quinone of strain JH31T was menaquinone 7 and the predominant cellular fatty acids were iso-C15:0, and summed feature 4 (comprising iso-C17:1 I and/or anteiso B). The major polar lipids were phosphatidylethanolamine, three unidentified glycolipids, one unidentified phospholipid, one unidentified phosphoglycolipid and one unidentified aminoglycolipid. The phylogenetic, physiochemical and biochemical data showed that strain JH31T should represent a novel species in the genus Pontibacter, for which the name Pontibacter aquaedesilientis sp. nov. is proposed. The type strain for this novel species is JH31T (KACC 21705T=NBRC 114480T).

Spatiotemporal change in coastal waters caused by land-based fish farm wastewater-borne nutrients: Results from Jeju Island, Korea.

We investigated spatiotemporal distributions of dissolved inorganic nutrients and organic carbon (DOC) and nitrogen (DON) in coastal waters and land-based fish farm wastewater to determine effects of wastewater on seawater of Jeju Island, Korea. The nutrient concentrations in seawater were lower than in wastewater with negative correlations against salinity, indicating a terrestrial source. Wastewater-derived DOC and DON were transported offshore while wastewater-derived inorganic nutrients were effectively removed, likely via biological production, and this was closely linked to decline in N:P ratios. The correlations between DOC, DON, and colored dissolved organic matter suggest that organic matters likely originate from the fish farm wastewater. Quantitatively, the estimated wastewater-derived DOC flux was equivalent to that through submarine groundwater, which is a significant water source on the island. Our results will be able to trace contaminant sources and support assessments of seawater quality for appropriate regulation of fish farm wastewater discharge into coastal zones.

Promotion effect of the propolis from Jeju Island, Korea, on NGF secretion in human glioblastoma cells.

Propolis is a resinous mixture of substances collected and processed from various botanical sources by honeybees (Apis mellifera). We previously found that propolis collected on Jeju Island, located off the southern coast of Korea, originates from a single plant, Angelica keiskei KOIDZUMI (Ashitaba). A. keiskei has been well-studied as a health food and has been reported to promote nerve growth factor (NGF) production. Propolis formed from the resin of A. keiskei is expected to have a similar promotional effect on NGF production. NGF is a potential pharmacological agent for Alzheimer's disease. In this study, the effects of an ethanolic extract of propolis from Jeju Island (EEPJ) on NGF secretion and cell viability in T98G human glioblastoma cells were evaluated. Ethanolic extracts of propolis from Brazil (Baccharis type) and from Uruguay (Populus type) were also studied for comparison. We found that EEPJ significantly increased NGF secretion in the cells in a concentration-dependent manner. Furthermore, the effects of 27 compounds previously isolated from EEPJ were also evaluated. Several compounds were found to have a promotion effect on NGF secretion, and the structure-activity relationships of the compounds were considered relative to their promotional effect on NGF biosynthesis. The promotional effect of EEPJ is a characteristic biological activity that is not present with other propolis types, so the propolis from Jeju Island may have potential applications as a therapeutic candidate for Alzheimer's disease.