Activity, stability, and binding capacity of ß-galactosidase immobilized on electrospun nylon-6 fiber membrane.

In this research, we explored various immobilized enzyme support materials, including the novel nylon-6 fiber membrane (NFM), and evaluated the increase in surface area and its effect on enzyme binding potential. We also manipulated incubation and reaction conditions and assessed the subsequent effects on activity and stability of ß-galactosidase, with comparisons between various solid support materials and free (dissolved) enzyme. Nylon-6 fiber membranes were created by electrospinning and were compared with other materials as solid supports for enzyme binding. The other materials included polyvinylidene fluoride 5-kDa nanofiltration dairy membranes, nylon-6 pellets, and silica glass beads. Scanning electron microscopy revealed the large surface area of NFM, which correlated with greater enzyme activity compared with the relatively flatter surfaces of the other solid support materials. Enzyme activity was measured spectrophotometrically with the color-changing substrate o-nitrophenyl-ß-d-galactopyranoside. Compared with the other solid supports, NFM had greater maximum enzyme binding potential. Across pH conditions ranging from 3.5 to 6.0 (including the optimal pH of 4.0-5.0), enzyme activity was maintained on the membrane-immobilized samples, whereas free enzyme did not maintain activity. Altering the storage temperature (4, 22, and 50°C) affected enzyme stability (i.e., the ability of the enzyme to maintain activity over time) of free and polyvinylidene fluoride membrane samples. However, NFM samples maintained stability across the varying storage temperatures. Increasing the immobilization solution enzyme concentration above the maximum enzyme binding capacity had no significant effect on enzyme stability for membrane-immobilized samples; however, both had lower mean stability than free enzyme by approximately 74%. With further development, ß-galactosidase immobilized on NFM or other membranes could be used in continuous processing in the dairy industry for a combination of filtration and lactose hydrolysis-creating products that are reduced in lactose and increased in sweetness, with no requirement for "added sugars" on the nutrition label and no enzyme listed as final product ingredient.

Occurrence of Taenia species in pigs in slaughterhouses in Phu Tho province, northern Vietnam.

Pigs act as the intermediate hosts of the zoonotic tapeworms Taenia solium and Taenia asiatica, as well as of the non-zoonotic Taenia hydatigena. In Vietnam, human taeniasis and cysticercosis have been reported throughout the country; however, data on porcine cysticercosis are scarce. Our study aimed to estimate the prevalence of Taenia spp. in slaughtered pigs in two districts in Phu Tho, a mountainous province in northern Vietnam from where neurocysticercosis patients commonly originate. The carcasses of 399 pigs from 51 small-scale abattoirs were checked for cysticerci, while tongue, liver, masseter muscles, diaphragm and heart were sliced and examined. Retrieved cysticerci underwent polymerase chain reaction-restriction fragment length polymorphism and sequencing for species confirmation. Blood was also collected to detect antibodies by lentil lectin-purified glycoprotein enzyme-linked immunoelectrotransfer blot (LLGP-EITB) and recombinant T24H antigen (rT24H)-EITB and circulating antigens by B158/B60 Ag-ELISA. In two pigs, T. asiatica cysticerci were found, confirming the presence of the parasite in pigs in Vietnam at a low prevalence (0.5%; 95% exact confidence interval (CI): 0-1.19%). Cysticerci of T. solium were found in none of the pigs, although one serum sample was positive for antibodies in both LLGP-EITB and rT24H-EITB. Furthermore, a high prevalence of T. hydatigena cysticercosis was observed (18.0%; 95% Wilson score CI: 14.6-22.1%). In more than half of the T. hydatigena-positive pigs, circulating antigens were detected by Ag-ELISA, confirming that this test cannot be used to diagnose T. solium cysticercosis in this region. Finally, Spirometra erinaceieuropaei was found in one pig liver. It is the first record of this zoonotic cestode species in pigs in Vietnam. Overall, the findings confirmed the complex epidemiology of Taenia spp. in pigs in Vietnam.

Landscape of Elderly Suicide in South Korea: Its Trend According to Age, Gender, and Educational Attainment.

South Korea has one of the highest suicide rates in the world, and the most alarming suicide rate is among its elders. This study aims to understand the social, historical, and cultural context of the Korean older adults and examine suicide trends based on that understanding. The results show that the suicide risk increases with age, the male suicide rate outweighs that of females, and the suicide rate decreases with educational attainment. In addition, several suggestions for reducing elderly suicide rate are addressed, including differentiating the existing social services for elders by age and expanding suicide prevention programs beyond schools to communities so that all people in need can access them.

Allergen-specific immunotherapy induces regulatory T cells in an atopic dermatitis mouse model.

BACKGROUND: Several studies have demonstrated that allergen-specific immunotherapy (SIT) can be an effective treatment for atopic dermatitis (AD). However, there is no relevant mouse model to investigate the mechanism and validate the novel modality of SIT in AD. METHODS: NC/Nga mice with induced AD-like skin lesions received a subcutaneous injection of SIT (an extract of the house dust mite Dermatophagoides farinae [DfE]) or placebo for 5 weeks). Clinical and histological improvements of AD-like skin lesions were examined. The responses of local and systemic regulatory T (Treg) cells, natural killer (NK) cells, B cells, serum immunoglobulin, and T-cell cytokine response to DfE were evaluated to determine the underlying mechanism of the observed results. RESULTS: Specific immunotherapy significantly improved AD-like skin lesions. Histologically, SIT decreased epidermal thickness and reduced inflammatory cell infiltration, especially that of eosinophils. Concomitantly, SIT suppressed Th2 responses and induced local infiltration of Treg cells into the skin. Also, SIT induced the immunoglobulin G4 and attenuated allergen-specific immunoglobulin E. Furthermore, SIT induced local and systemic IL-10-producing Treg cells and regulatory NK cells. CONCLUSION: We established a SIT model on AD mice and showed that our model correlates well with previous reports about SIT-treated patients. Also, we revealed NK cells as another possible resource of IL-10 in SIT. Based on our results, we suggest our SIT model as a useful tool to investigate mechanism of action of SIT and to validate the efficacy of new SIT modalities for the treatment of AD.

DOCK8: regulator of Treg in response to corticotropin-releasing hormone.

BACKGROUND: Atopic dermatitis (AD) is exacerbated by psychological factors, such as stress. We previously reported that corticotrophin-releasing hormone (CRH) treatment in AD patients decreased the proportion of IL-10(+) Tr1 cells, a subset of inducible regulatory T cells (Tregs). However, changes in the function of Tregs in response to CRH have yet to be studied. METHODS: We analyzed the total proteins taken from CRH-treated and untreated Tregs from AD mice model (NC/Nga mice) using a quantitative proteomic analysis for the different protein expressions. RESULTS: We found a statistically decreased protein level of DOCK8 in CRH-treated Tregs from AD mice. In human, DOCK8 protein levels were also significantly decreased in CRH-treated Tregs from AD patients. Moreover, the expression of DOCK8 in Tregs was inversely correlated with the anxiety levels in the AD patients. In addition to the clinical correlation of DOCK8 with the stress level of AD patients, the knockdown of DOCK8 in Tregs reduced the inhibitory cytokines, IL-10 and TGF-ß, and inhibited the regulatory function of Tregs to suppress the proliferation and TNF-α release of CD4(+) T cells in vitro. CONCLUSION: This study provides new insights on the mechanisms of stress-induced AD aggravation by showing that CRH downregulated DOCK8 expression in Tregs that not only clinically correlates with anxiety levels of AD patients but also regulates suppressive function of Tregs on CD4(+) T cells.

Prevalence and prognosis of hypoglycaemia in patients receiving maintenance dialysis.

BACKGROUND: End-stage renal disease is a common predisposing condition for the development of hypoglycaemia. AIM: To determine the effect of hypoglycaemia on the mortality of patients undergoing maintenance dialysis. METHODS: Retrospective and descriptive analyses were performed in five dialysis centres in the Republic of Korea between June 2002 and August 2008. We enrolled 1685 patients who had undergone dialysis for at least 1 month. RESULTS: We identified 453 episodes of hypoglycaemia in 256 of 1685 patients (15.2%); 189 patients (73.8%) had diabetes, whereas the other patients did not. The occurrence of hypoglycaemia in patients receiving dialysis appeared to be a life-threatening complication because 27.0% of patients died within two days of the onset of a hypoglycaemic episode. Older age, low serum albumin levels and infections were independent risk factors for total mortality in these patients. Furthermore, the absence of diabetes, age and serum glucose levels were independent factors associated with early mortality within two days of the development of hypoglycaemia. CONCLUSION: Although several factors were associated with mortality, the degree of hypoglycaemia, absence of diabetes and old age were associated with early mortality. Elderly hypoglycaemic patients, especially those without diabetes, should be closely monitored.

Supplementary tibial fixation in anterior cruciate ligament reconstruction - Direct cortical fixation using spiked washer screw vs. post-tie using washer screw.

We compare clinical outcomes of two different supplementary tibial fixation in anterior cruciate ligament (ACL) reconstruction using free tendon Achilles allograft. Eighty subjects underwent ACL reconstruction using Endobutton CL for femoral fixation and Bio-interference screw for tibial fixation. Supplementary tibial fixation was performed as direct -cortical fixation using spiked washer screw (group I) or as post-tie using washer screw (group II). -Lachman test, pivot shift test, IKDC classification, Lysholm score, and side-to-side difference (SSD) were evaluated. Thirty six in group I and thirty five in group II could follow up for at least 2 years. At the last follow-up, 7 in group I and 1 in group II showed 2+ or 3+ in Lachman test (p = 0.027). Mean SSD was 2.4mm in group I and 1.4mm in group II (p = 0.048). Post-tie using washer screw was more effective than direct cortical fixation using spiked washer screw to restore stability. Level of evidence : Therapeutic Level I ; Randomized controlled clinical trial.

Association of heart rate with albuminuria in a general adult population: the 2011 Korea National Health and Nutrition Examination Survey.

BACKGROUND: Albuminuria is associated with increased risk of multiple adverse health outcomes, such as progressive renal failure, cardiovascular disease and death. However, in the general population, it is uncertain whether albuminuria is associated with elevated heart rate, which is an independent and powerful risk factor for cardiovascular disease. AIM: To investigate whether an elevated heart rate is an independent factor associated with albuminuria in the general adult population of Korea. METHODS: A cross-sectional analysis was carried out on 5198 Korean adults aged 19 years or older who participated in the fifth (2011) Korea National Health and Nutrition Examination Survey (KNHANES V-2). RESULTS: The prevalence of albuminuria showed an increasing trend throughout the whole range of heart rate, even after adjusting for confounders (P = 0.002). The increment was most profound at the heart rate of 70-75 and >76 beats per minute (b.p.m.; P = 0.011). In multiple logistic regression analysis, age (P < 0.001), hypertension (P < 0.001), diabetes (P < 0.001), hypertriglyceridaemia (P = 0.025), estimated glomerular filtration rate (P = 0.028) and heart rate (P = 0.023) were independently associated with the presence of albuminuria in Korean adults. Compared with participants with heart rate ≤ 64 b.p.m., the odds ratio (95% CI) for albuminuria was 1.50 (1.15-1.96) for those with heart rate ≥ 76 b.p.m. CONCLUSIONS: The prevalence of albuminuria is independently associated with heart rate in the general adult population of Korea.

Is elective nodal irradiation beneficial in patients with pathologically negative lymph nodes after neoadjuvant chemotherapy and breast-conserving surgery for clinical stage II-III breast cancer? A multicentre retrospective study (KROG 12-05).

BACKGROUND: To evaluate the effects of elective nodal irradiation (ENI) in clinical stage II-III breast cancer patients with pathologically negative lymph nodes (LNs) (ypN0) after neoadjuvant chemotherapy (NAC) followed by breast-conserving surgery (BCS) and radiotherapy (RT). METHODS: We retrospectively analysed 260 patients with ypN0 who received NAC followed by BCS and RT. Elective nodal irradiation was delivered to 136 (52.3%) patients. The effects of ENI on survival outcomes were evaluated. RESULTS: After a median follow-up period of 66.2 months (range, 15.6-127.4 months), 26 patients (10.0%) developed disease recurrence. The 5-year locoregional recurrence-free survival and disease-free survival (DFS) for all patients were 95.5% and 90.5%, respectively. Pathologic T classification (0-is vs 1 vs 2-4) and the number of LNs sampled (<13 vs ≥13) were associated with DFS (P=0.0086 and 0.0012, respectively). There was no significant difference in survival outcomes according to ENI. Elective nodal irradiation also did not affect survival outcomes in any of the subgroups according to pathologic T classification or the number of LNs sampled. CONCLUSIONS: ENI may be omitted in patients with ypN0 breast cancer after NAC and BCS. But until the results of the randomised trials are available, patients should be put on these trials.

Viral load dynamics in adult patients with A(H1N1)pdm09 influenza.

SUMMARY The dynamics of influenza A viral load in respiratory samples collected from adult A(H1N1)pdm09 influenza patients were investigated. Three respiratory specimens were obtained every 2-4 days and clinical findings were recorded at the time each specimen was collected. A total of 105 serial specimens were collected from 35 patients. Viral clearance was more rapid in patients aged 15-29 years than patients aged 30-49 years (P < 0.01) or ≥ 50 years (P < 0.01). Hospitalized patients showed slow viral clearance compared to outpatients (P < 0.01). Resolution of cough and headache was correlated with viral load reduction in respiratory specimens. Viral shedding was found in 17 patients (48.6%) 5 days after symptom onset. Time to hospital visit after symptom onset was significantly correlated with prolonged viral shedding (odds ratio 9.0, 95% confidence interval 1.56-51.87, P = 0.01). These findings will contribute to infection control aspects with respect to managing patients with influenza virus infections.

Inactivation of the lpcC gene alters surface-related properties and symbiotic capability of Bradyrhizobium japonicum.

UNLABELLED: We investigated the role of the Bradyrhizobium japonicum lpcC gene, encoding a mannosyl transferase, involved in the lipopolysaccharide (LPS) biosynthesis. The inactivation of the lpcC gene considerably altered the LPS structure and the cell surface properties. LPS analysis showed that the lpcC mutant JS715 had an abnormal LPS structure deficient in O-antigen. The cell surface hydrophobicity increased approximately threefold in JS715 compared to the wild type. The increased cell surface hydrophobicity is likely to be related with cell aggregation in the mutant culture. For the growth comparison, JS715 showed slower growth rate than the wild type. The motility of JS715 decreased in soft agar plates, but it showed enhanced biofilm-forming ability. Interestingly, JS715 was not able to nodulate the host legume soybean (Glycine max). This study shows not only that lpcC is involved in the biosynthesis of O-antigen in the B. japonicum LPS, but also that inactivation of the lpcC gene affects symbiotic capability of B. japonicum and surface-related properties such as cell hydrophobicity, biofilm formation and motility. SIGNIFICANCE AND IMPACT OF THE STUDY: This study demonstrates the role of the B. japonicum lpcC in nodulation with soybean and importance of cell surface hydrophobicity. The results also highlight that intact LPS is required for successful symbiosis between B. japonicum and soybeans. Our findings not only support previous studies emphasizing the necessity of LPS on the interaction between the two symbiotic partners, but also contribute to a better understanding of the symbiotic mechanisms.

Predictive factors for lymph node metastasis in patients with poorly differentiated early gastric cancer.

BACKGROUND: Endoscopic submucosal dissection is gaining popularity in the treatment of early gastric cancer. This study aimed to identify clinicopathological factors predictive of lymph node metastasis in patients with the poorly differentiated early gastric cancer to assess the feasibility of using endoscopic submucosal dissection for these cancers. METHODS: The records of patients with poorly differentiated early gastric cancer who had undergone gastric cancer surgery between January 2002 and December 2009 were reviewed. Associations between clinicopathological factors and the presence of lymph node metastasis were analysed by univariable and multivariable logistic regression analysis. RESULTS: Some 1005 patients were included in the analysis. Univariable analysis indicated that lymph node metastasis was associated with sex, ulceration, tumour size, depth of invasion, macroscopic type, lymphatic invasion and venous invasion. Logistic regression revealed that lymph node metastasis was significantly associated with sex, tumour size, depth of tumour invasion and lymphatic involvement. In the group with none of these risk factors (men with mucosal tumour no larger than 2 cm in size, with no lymphatic involvement), lymph node metastasis was present in four (3·2 per cent) of 124 patients. CONCLUSION: In the present study 3·2 per cent of patients who were negative for all identified risk factors had lymph node metastasis. The use of endoscopic submucosal dissection should be considered carefully in the treatment of poorly differentiated early gastric cancer.

Synthesis and electroplating of high resolution insulated carbon nanotube scanning probes for imaging in liquid solutions.

High resolution and isolated scanning probe microscopy (SPM) is in demand for continued development of energy storage and conversion systems involving chemical reactions at the nanoscale as well as an improved understanding of biological systems. Carbon nanotubes (CNTs) have large aspect ratios and, if leveraged properly, can be used to develop high resolution SPM probes. Isolation of SPM probes can be achieved by depositing a dielectric film and selectively etching at the apex of the probe. In this paper the fabrication of a high resolution and isolated SPM tip is demonstrated using electron beam induced etching of a dielectric film deposited onto an SPM tip with an attached CNT at the apex.

Prevalence and antimicrobial resistance of Salmonella species isolated from chicken meats produced by different integrated broiler operations in Korea.

Prevalence and antimicrobial resistance profiles of Salmonella serotypes isolated from 7 chicken meat brands produced by different integrated broiler operations in Korea were determined. In total, 210 samples were collected from retail supermarkets in Seoul, South Korea, and analyzed for the presence of Salmonella. Of 210 chicken meat samples, overall Salmonella prevalence was 22.4%. Salmonella Enteritidis was the dominant serovar, with an isolation rate of 57.4% from the Salmonella-positive chickens, followed by Salmonella Montevideo. Salmonella isolates frequently were resistant to various antibiotics, including 100% to erythromycin, 87% to cephalothin, 85% to nalidixic acid, and 70% to streptomycin. Of the 47 isolates, 41 (87.2%) isolates were resistant to 3 or more antibiotics. Moreover, the Salmonella profiles of each chicken meat brand were different by broiler operation. Brand A showed the highest prevalence of Salmonella (18 isolates, 60%), whereas brand G showed the lowest prevalence (one isolate, 3.3%). Eight among the 18 isolates of brand A were resistant to 11 antibiotics, whereas 5 of the 6 brand C isolates were resistant to only 2 antibiotics. This study demonstrates that a high proportion of chicken meat in Korea is contaminated with Salmonella and the prevalence and antimicrobial resistance patterns of Salmonella of chicken meat differ significantly according to the integrated broiler operation.

Surgical outcome after incomplete endoscopic submucosal dissection of gastric cancer.

BACKGROUND: Endoscopic resection of early gastric cancer is a relatively new and attractive treatment, but occasionally fails to remove all cancer lesions completely. This study aimed to elucidate clinicopathological factors that could be helpful in predicting residual tumour in the surgical specimen after incomplete endoscopic submucosal dissection (ESD). METHODS: Patients who underwent gastrectomy because of incomplete ESD between August 2004 and August 2008 were analysed. Clinicopathological characteristics were reviewed retrospectively from prospectively collected medical records. Patients were classified into groups with and without residual tumour. Pathology results following gastrectomy were compared with those of incomplete ESD. RESULTS: A total of 118 patients were included. The incidence of residual tumour in the surgical specimen was 24·6 per cent after incomplete ESD. Elevated/flat-type cancers, large tumours (at least 2 cm) and those limited to the mucosa had significantly higher incomplete ESD rates. Cancer limited to the mucosa and the presence of tumour in the lateral margin were associated with residual tumour in the surgical specimen (both P = 0·001). CONCLUSION: Radical gastrectomy should be performed if pathological examination reveals a positive lateral resection margin after ESD.

Dependence of milling time on electrochemical properties of nano Si electrodes prepared by ball-milling.

Morphology, crystallinity and electrochemical properties of Si powders fabricated by a mechanical milling process with milling time of 6-40 h were investigated by means of FESEM, XRD, Raman, TEM and cell test. Average size of Si powders was reduced to sub-micrometer scale after 10 h-milling and 40 nm-Si powders could be obtained at 48 h-milling. With increasing milling time, Si powders mostly changes from crystalline Si to amorphous one and the content of amorphous Si was increased. TEM result showed that a negligiable amount of crystalline Si remained even after 48 h-milling. Si electrode with 48 h-milled Si powders exhibited the best electrochemical properties in terms of capacity, efficiency and cycle performance: initial capacity of 3025 mAh g(-1), coulrombic efficiency of 79.4% and the capacity retention of 1000 mAh g(-1) (at 130 cycles). The good electrochemical properties of nano- and amorphous-Si are due to the high resistance against volume change and good reversibility of Li ion.

Population genetic structure of wild and hatchery black rockfish Sebastes inermis in Korea, assessed using cross-species microsatellite markers.

The population structure of the black rockfish, Sebastes inermis (Sebastidae), was estimated using 10 microsatellite loci developed for S. schlegeli on samples of 174 individuals collected from three wild and three hatchery populations in Korea. Reduced genetic variation was detected in hatchery strains [overall number of alleles (N(A)) = 8.07; allelic richness (A(R)) = 7.37; observed heterozygosity (H(O)) = 0.641] compared with the wild samples (overall N(A) = 8.43; A(R) = 7.83; H(O) = 0.670), but the difference was not significant. Genetic differentiation among the populations was significant (overall F(ST) = 0.0237, P < 0.05). Pairwise F(ST) tests, neighbor-joining tree, and principal component analyses showed significant genetic heterogeneity among the hatchery strains and between wild and hatchery strains, but not among the wild populations, indicating high levels of gene flow along the southern coast of Korea, even though the black rockfish is a benthic, non-migratory marine species. Genetic differentiation among the hatchery strains could reflect genetic drift due to intensive breeding practices. Thus, in the interests of optimal resource management, genetic variation should be monitored and inbreeding controlled within stocks in commercial breeding programs. Information on genetic population structure based on cross-species microsatellite markers can aid in the proper management of S. inermis populations.

Internal and external environmental factors affecting the performance of hospital-based home nursing care.

BACKGROUND: Numerous studies on HNC services have been carried out by signifying their needs, efficiency and effectiveness. However, no study has ever been performed to determine the critical factors associated with HNC's positive results despite the deluge of positive studies on the service. METHODS: This study included all of the 89 training hospitals that were practising HNC service in Korea as of November 2006. The input factors affecting the performance were classified as either internal or external environmental factors. This analysis was conducted to understand the impact that the corresponding factors had on performance. Data were analysed by using multiple linear regressions. RESULTS: The internal and external environment variables affected the performance of HNC based on univariate analysis. The meaningful variables were internal environmental factors. Specifically, managerial resource (the number of operating beds and the outpatient/inpatient ratio) were meaningful when the multiple linear regression analysis was performed. Indeed, the importance of organizational culture (the passion of HNC nurses) was significant. CONCLUSION: This study, considering the limited market size of Korea, illustrates that the critical factor for the development of hospital-led HNC lies with internal environmental factors rather than external ones. Among the internal environmental factors, the hospitals' managerial resource-related factors (specifically, the passion of nurses) were the most important contributing element.

Comparison of the efficacy and safety of tramadol/acetaminophen combination therapy and gabapentin in the treatment of painful diabetic neuropathy.

AIMS: This study compared the efficacy and safety of tramadol/acetaminophen (T/A) and gabapentin in the management of painful diabetic neuropathy. METHODS: An open, randomized, comparative study was conducted. Subjects with painful symmetric neuropathy in the lower limbs and mean pain-intensity score > or = 4 on a numeric rating scale were eligible. Subjects were randomized to receive either tramadol (37.5 mg)/acetaminophen (325 mg) or gabapentin (300 mg) for 6 weeks. After 2 weeks of the titration period (1200 mg/day for gabapentin and three tablets/day for T/A), the doses were maintained if the pain was relieved. The primary efficacy outcome was a reduction in pain intensity. Secondary measures evaluated a pain relief scale, a Brief Pain Inventory, a 36-item Short Form Health Survey, average pain intensity and sleep disturbance. RESULTS: One hundred and sixty-three subjects (T/A 79; gabapentin 84) were included. At the final visit, the mean doses were 1575 mg/day for gabapentin and 4.22 tablets/day for T/A. Both groups were similar in terms of baseline pain intensity (mean intensity: T/A 6.7 +/- 1.6; gabapentin 6.3 +/- 1.6, P = 0.168). At the final visit, the mean reductions in pain intensity were similar in both groups (T/A -3.1 +/- 2.0; gabapentin -2.7 +/- 2.1, P = 0.744). Both groups had similar improvements in every Short Form Health Survey category and Brief Pain Inventory subcategory, and in the mean pain relief scores. CONCLUSION: This study suggests that the T/A combination treatment is as effective as gabapentin in the treatment of painful diabetic neuropathy in patients with Type 2 diabetes.

Population structure of the olive flounder (Paralichthys olivaceus) in Korea inferred from microsatellite marker analysis.

The population structure of olive flounder Paralichthys olivaceus was estimated using nine polymorphic microsatellite (MS) loci in 459 individuals collected from eight populations, including five wild and three hatchery populations in Korea. Genetic variation in hatchery (mean number of alleles per locus, A = 10.2-12.1; allelic richness, A(R) = 9.3-10.1; observed heterozygosity, H(O) = 0.766-0.805) and wild (mean number of alleles per locus, A = 11.8-19.6; allelic richness, A(R) = 10.9-16.1; observed heterozygosity, H(O) = 0.820-0.888) samples did not differ significantly, suggesting a sufficient level of genetic variation in these well-managed hatchery populations, which have not lost a substantial amount of genetic diversity. Neighbour-joining tree and principal component analyses showed that genetic separation between eastern and pooled western and southern wild populations in Korea was probably influenced by restricted gene flow between regional populations due to the barrier effects of sea currents. The pooled western and southern populations are genetically close, perhaps because larval dispersal may depend on warm currents. One wild population (sample from Wando) was genetically divergent from the main distribution, but it was genetically close to hatchery populations, indicating that the genetic composition of the studied populations may be affected by hydrographic conditions and the release of fish stocks. The estimated genetic population structure and potential applications of MS markers may aid in the proper management of P. olivaceus populations.