Association between nut consumption and low muscle strength among Korean adults.

Nuts are an important component of a healthy diet, but little has been known about their effects on muscle health. Therefore, this study examined the association between nut consumption and low muscle strength among Korean adults. This cross-sectional analysis was conducted using single 24-h recall and handgrip strength data from 3962 younger adults 19-39 years, 6921 middle-aged adults 40-64 years and 3961 older adults ≥65 years participated in the seventh cycle (2016-2018) of the Korea National Health and Nutrition Examination Survey. Low muscle strength was defined as handgrip strength <28 kg for men and <18 kg for women. Sex-specific OR were obtained for younger, middle-aged and older adults using multivariable logistic regression analyses. About one in four Korean adults were consuming nuts (using a culinary definition) with peanut being the most frequently consumed type. After adjustment for age, BMI, total energy intake, household income, alcohol consumption, smoking, resistance exercise, medical history and dietary protein intake, nut consumption was associated with the lower risk of low muscle strength among older adults ≥65 years (men: OR 0·55, 95 % CI (0·38, 0·79); women: OR 0·69, 95 % CI (0·51, 0·93)); however, this association was not observed among younger adults 19-39 years or middle-aged adults 40-64 years. Our results suggest that consuming nuts might be beneficial in lowering the risk of low muscle strength among Korean older adults.

Anti-Obesity Activities of the Compounds from Perilla frutescens var. acuta and Chemical Profiling of the Extract.

Perilla frutescens var. acuta (Lamiaceae) is widely used not only as an oil or a spice, but also as a traditional medicine to treat colds, coughs, fever, and indigestion. As an ongoing effort, luteolin-7-O-diglucuronide (1), apigenin-7-O-diglucuronide (2), and rosmarinic acid (3) isolated from P. frutescens var. acuta were investigated for their anti-adipogenic and thermogenic activities in 3T3-L1 cells. Compound 1 exhibited a strong inhibition against adipocyte differentiation by suppressing the expression of Pparg and Cebpa over 52.0% and 45.0%, respectively. Moreover, 2 inhibited the expression of those genes in a dose-dependent manner [Pparg: 41.7% (5 µM), 62.0% (10 µM), and 81.6% (50 µM); Cebpa: 13.8% (5 µM), 18.4% (10 µM), and 37.2% (50 µM)]. On the other hand, the P. frutescens var. acuta water extract showed moderate thermogenic activities. Compounds 1 and 3 also induced thermogenesis in a dose-dependent manner by stimulating the mRNA expressions of Ucp1, Pgc1a, and Prdm16. Moreover, an LC-MS/MS chromatogram of the extract was acquired using UHPLC-MS2 and it was analyzed by feature-based molecular networking (FBMN) and the Progenesis QI software (version 3.0). The chemical profiling of the extract demonstrated that flavonoids and their glycoside derivatives, including those isolated earlier as well as rosmarinic acid, are present in P. frutescens var. acuta.

Ceramide Synthase 2 Null Mice Are Protected from Ovalbumin-Induced Asthma with Higher T Cell Receptor Signal Strength in CD4+ T Cells.

(1) Background: six mammalian ceramide synthases (CerS1-6) determine the acyl chain length of sphingolipids (SLs). Although ceramide levels are increased in murine allergic asthma models and in asthmatic patients, the precise role of SLs with specific chain lengths is still unclear. The role of CerS2, which mainly synthesizes C22-C24 ceramides, was investigated in immune responses elicited by airway inflammation using CerS2 null mice. (2) Methods: asthma was induced in wild type (WT) and CerS2 null mice with ovalbumin (OVA), and inflammatory cytokines and CD4 (cluster of differentiation 4)+ T helper (Th) cell profiles were analyzed. We also compared the functional capacity of CD4+ T cells isolated from WT and CerS2 null mice. (3) Results: CerS2 null mice exhibited milder symptoms and lower Th2 responses than WT mice after OVA exposure. CerS2 null CD4+ T cells showed impaired Th2 and increased Th17 responses with concomitant higher T cell receptor (TCR) signal strength after TCR stimulation. Notably, increased Th17 responses of CerS2 null CD4+ T cells appeared only in TCR-mediated, but not in TCR-independent, treatment. (4) Conclusions: altered Th2/Th17 immune response with higher TCR signal strength was observed in CerS2 null CD4+ T cells upon TCR stimulation. CerS2 and very-long chain SLs may be therapeutic targets for Th2-related diseases such as asthma.

Suppressing Pyroptosis Augments Post-Transplant Survival of Stem Cells and Cardiac Function Following Ischemic Injury.

The acute demise of stem cells following transplantation significantly compromises the efficacy of stem cell-based cell therapeutics for infarcted hearts. As the stem cells transplanted into the damaged heart are readily exposed to the hostile environment, it can be assumed that the acute death of the transplanted stem cells is also inflicted by the same environmental cues that caused massive death of the host cardiac cells. Pyroptosis, a highly inflammatory form of programmed cell death, has been added to the list of important cell death mechanisms in the damaged heart. However, unlike the well-established cell death mechanisms such as necrosis or apoptosis, the exact role and significance of pyroptosis in the acute death of transplanted stem cells have not been explored in depth. In the present study, we found that M1 macrophages mediate the pyroptosis in the ischemia/reperfusion (I/R) injured hearts and identified miRNA-762 as an important regulator of interleukin 1ß production and subsequent pyroptosis. Delivery of exogenous miRNA-762 prior to transplantation significantly increased the post-transplant survival of stem cells and also significantly ameliorated cardiac fibrosis and heart functions following I/R injury. Our data strongly suggest that suppressing pyroptosis can be an effective adjuvant strategy to enhance the efficacy of stem cell-based therapeutics for diseased hearts.

A Novel Selective Sphingosine Kinase 2 Inhibitor, HWG-35D, Ameliorates the Severity of Imiquimod-Induced Psoriasis Model by Blocking Th17 Differentiation of Naïve CD4 T Lymphocytes.

Sphingosine kinases (SK) catalyze the phosphorylation of sphingosine to generate sphingosine-1-phosphate. Two isoforms of SK (SK1 and SK2) exist in mammals. Previously, we showed the beneficial effects of SK2 inhibition, using ABC294640, in a psoriasis mouse model. However, ABC294640 also induces the degradation of SK1 and dihydroceramide desaturase 1 (DES1). Considering these additional effects of ABC294640, we re-examined the efficacy of SK2 inhibition in an IMQ-induced psoriasis mouse model using a novel SK2 inhibitor, HWG-35D, which exhibits nM potency and 100-fold selectivity for SK2 over SK1. Topical application of HWG-35D ameliorated IMQ-induced skin lesions and normalized the serum interleukin-17A levels elevated by IMQ. Application of HWG-35D also decreased skin mRNA levels of interleukin-17A, K6 and K16 genes induced by IMQ. Consistent with the previous data using ABC294640, HWG-35D also blocked T helper type 17 differentiation of naïve CD4+ T cells with concomitant reduction of SOCS1. Importantly, HWG-35D did not affect SK1 or DES1 expression levels. These results reaffirm an important role of SK2 in the T helper type 17 response and suggest that highly selective and potent SK2 inhibitors such as HWG-35D might be of therapeutic use for the treatment of psoriasis.

Inhibiting Sphingosine Kinase 2 Derived-sphingosine-1-phosphate Ameliorates Psoriasis-like Skin Disease via Blocking Th17 Differentiation of Naïve CD4 T Lymphocytes in Mice.

Sphingosine-1-phosphate (S1P) is a signalling sphingolipid metabolite that regulates important cell processes, including cell proliferation and apoptosis. Circulating S1P levels have been reported to be increased in patients with psoriasis relative to healthy patients. The aim of this study was to examine the potency of S1P inhibition using an imiquimod-induced psoriasis mouse model. Both topical ceramidase and sphingosine kinase 1/2 inhibition, which blocks S1P generation, alleviated imiquimod-induced skin lesions and reduced the serum interleukin 17-A levels induced by application of imiquimod. These treatments also normalized skin mRNA levels of genes associated with inflammation and keratinocyte differentiation. Inhibition of sphingosine kinase 2, but not sphingosine kinase 1, diminished levels of suppressor of cytokine signalling 1 and blocked T helper type 17 differentiation of naïve CD4+ T cells; imiquimod-induced psoriasis-like skin symptoms were also ameliorated. These results indicate the distinct effects of sphingosine kinase 1 and sphingosine kinase 2 inhibition on T helper type 17 generation and suggest molecules that inhibit S1P formation, including ceramidase and sphingosine kinase 2 inhibitors, as novel therapeutic candidates for psoriasis.

Distribution of Rickettsia spp. in Ticks from Northwestern and Southwestern Provinces, Republic of Korea.

This study was done to characterize distribution of Rickettsia spp. in ticks in the northwestern and southwestern provinces in the Republic of Korea. A total of 2,814 ticks were collected between May and September 2009. After pooling, 284 tick DNA samples were screened for a gene of Rickettsia-specific 17-kDa protein using nested PCR (nPCR), and produced 88 nPCR positive samples. Of these positives, 75% contained 190-kDa outer membrane protein gene (ompA), 50% 120-kDa outer membrane protein gene (ompB), and 64.7% gene D (sca4). The nPCR products of ompA, ompB, and sca4 genes revealed close relatedness to Rickettsia japonica, R. heilongjiangensis, and R. monacensis. Most Rickettsia species were detected in Haemaphysalis longicornis. This tick was found a dominant vector of rickettsiae in the study regions in the Republic of Korea.

microRNA-133a attenuates cardiomyocyte hypertrophy by targeting PKCδ and Gq.

During the past decade, microRNAs have continuously been suggested as a promising therapeutic tool due to their beneficial effects, such as their multi-targets and multi-functions in pathologic conditions. As a pathologic phenotype is generally regulated by multiple signaling pathways, in this study we identified a microRNA regulating multiple target genes within cardiac hypertrophic signaling pathways. microRNA-133a is known to play a crucial role in cardiac hypertrophy. However, the role of microRNA-133a, which may regulate several signaling pathways in norepinephrine-induced cardiac hypertrophy via multi-targeting, has not been investigated. In the current study, we showed that microRNA-133a can protect cardiomyocyte hypertrophy against norepinephrine stimulation in neonatal rat ventricular cardiomyocytes via new targets, PKCδ and Gq, all of which are related to downstream signaling pathways of the α1-adrenergic receptor. Taken together, these results suggest the advantages of the therapeutic use of microRNAs as an effective potential drug regulating multiple signaling pathways under pathologic conditions.

Anti-apoptotic effects of adipose-derived adherent stromal cells in mesenchymal stem cells exposed to oxidative stress.

Adipose-derived stromal vascular fractions (SVFs) are a heterogeneous collection of cells, and their regenerative modality has been applied in various animal experiments and clinical trials. Despite the attractive advantages of SVFs in clinical interventions, the recent status of clinical studies involving the application of SVFs in many diseases has not been fully evaluated. Mesenchymal stem cells (MSCs) are multipotent stromal cells that can differentiate into a variety of cell types despite their low numbers in heart tissue. Here, we sought to determine if SVF implantation into impaired heart tissue affected endogenous MSCs in the heart. Therefore, we investigated the expression levels of proteins associated with oxidation, inflammation, and apoptosis in MSCs co-cultured with adipose-derived adherent stromal cells (ADASs) from 6 donors' SVFs under oxidative stress conditions for their roles in many physiological processes in the heart. Interestingly, p53 pathway proteins and mitogen-activated protein kinase (MAPK) signalling pathway components were up-regulated by H2 O2 but exhibited a downward trend in MSCs co-cultured with ADASs. These data suggest that ADASs may inhibit oxidative stress-induced apoptosis in MSCs via the p53 and MAPK pathways. Our findings also suggest that the positive effects of SVF implantation into damaged heart tissue may be attributed to the various responses of MSCs. This finding may provide new insights for the clinical application of adipose-derived SVF transplantation in cardiac diseases. SIGNIFICANCE OF THE STUDY: We investigated the expression levels of proteins associated with oxidation, inflammation, and apoptosis in MSCs co-cultured with isolated ADASs from 6 donors' SVFs under oxidative stress conditions. Our results imply that isolated ADASs from SVFs may inhibit oxidative stress-induced cell cycle arrest and/or apoptosis in MSCs via a p53-dependent pathway. Furthermore, we identified an anti-apoptotic mechanism involving oxidative stress-induced apoptosis by adipose-derived ADASs in MSCs for the first time. Our findings suggest that the positive effects of SVF implantation into damaged heart tissue may be attributed to the various actions of MSCs.

(-)-Epigallocatechin gallate derivatives reduce the expression of both urokinase plasminogen activator and plasminogen activator inhibitor-1 to inhibit migration, adhesion, and invasion of MDA-MB-231 cells.

Urokinase plasminogen activator (uPA) and its inhibitor plasminogen activator inhibitor-1 (PAI-1) are established independent biomarkers for high metastasis risk in breast cancer. In this study, we investigated the regulatory activity of (-)-epigallocatechin-3-gallate (EGCG) and its derivatives on uPA and PAI-1 expression and thereby their anti-metastatic potential. EGCG showed only marginal effects on the uPA system and on the metastatic behavior of breast cancer cells (MDA-MB-231). However, the EGCG derivative 3e with a methyl-substituted carbonate substituent at the 4″-position showed potent inhibition of PAI-1 (62%) and uPA (50%) expression. The Ras-extracellular-signal-regulated kinase (ERK), p38 mitogen-activated protein kinase (MAPK), and phosphatidylinositol-3-kinase (PI3K)/Akt/NF-κB pathways, which regulate uPA and PAI-1 expression, were also affected by 3e (25%, 45%, and 25% reduction, respectively). In line with these findings, substantial reduction in metastatic behavior of MDA-MB-231 cells, such as adhesion (40%), invasion (56%), and migration (40%), was observed in the presence of 3e. It is also noteworthy that, in MDA-MB-231 cells, 3e did not exert any beneficial effect on the expression of matric metalloprotein (MMP) 2 and 9, which indicates that the anti-metastatic activity of 3e in MDA-MB-231 cells is not related to its regulation of the expression of MMPs. Taken together, we have shown that the EGCG derivative 3e could suppress the metastatic behavior of MDA-MB-231 cells through regulation of uPA and PAI-1.

Ablation of ceramide synthase 2 exacerbates dextran sodium sulphate-induced colitis in mice due to increased intestinal permeability.

Ceramides mediate crucial cellular processes including cell death and inflammation and have recently been implicated in inflammatory bowel disease. Ceramides consist of a sphingoid long-chain base to which fatty acids of various length can be attached. We now investigate the effect of alerting the ceramide acyl chain length on a mouse model of colitis. Ceramide synthase (CerS) 2 null mice, which lack very-long acyl chain ceramides with concomitant increase of long chain bases and C16-ceramides, were more susceptible to dextran sodium sulphate-induced colitis, and their survival rate was markedly decreased compared with that of wild-type littermates. Using mixed bone-marrow chimeric mice, we showed that the host environment is primarily responsible for intestinal barrier dysfunction and increased intestinal permeability. In the colon of CerS2 null mice, the expression of junctional adhesion molecule-A was markedly decreased and the phosphorylation of myosin light chain 2 was increased. In vitro experiments using Caco-2 cells also confirmed an important role of CerS2 in maintaining epithelial barrier function; CerS2-knockdown via CRISPR-Cas9 technology impaired barrier function. In vivo myriocin administration, which normalized long-chain bases and C16-ceramides of the colon of CerS2 null mice, increased intestinal permeability as measured by serum FITC-dextran levels, indicating that altered SLs including deficiency of very-long-chain ceramides are critical for epithelial barrier function. In conclusion, deficiency of CerS2 influences intestinal barrier function and the severity of experimental colitis and may represent a potential mechanism for inflammatory bowel disease pathogenesis.

Rapid Induction of Osteogenic Markers in Mesenchymal Stem Cells by Adipose-Derived Stromal Vascular Fraction Cells.

BACKGROUND/AIMS: Stromal vascular fraction (SVF) cells are a mixed cell population, and their regenerative capacity has been validated in various therapeutic models. The purpose of this study was to investigate the regenerative mechanisms utilized by implanted SVF cells. Using an in vitro co-culture system, we sought to determine whether SVF implantation into impaired tissue affects endogenous mesenchymal stem cell (MSC) differentiation; MSCs can differentiate into a variety of cell types, and they have a strong regenerative capacity despite their low numbers in impaired tissue. METHODS: Adipose-derived SVF cells obtained from four donors were co-cultured with bone marrow-derived MSCs, and the differential expression of osteogenic markers and osteogenic differentiation inducers over time was analyzed in mono-cultured MSCs and MSCs co-cultured with SVF cells. RESULTS: The co-cultivation of MSCs with SVF cells significantly and mutually induced the expression of osteogenic-specific markers via paracrine and/or autocrine regulation but did not induce adipocyte, chondrocyte or myoblast marker expression. More surprisingly, subsequent osteogenesis and/or comparable effects were rapidly induced within 48 h. CONCLUSION: To the best of our knowledge, this is the first study in which osteogenesis and/or comparable effects were rapidly induced in bone marrow-derived MSCs and adipose-derived SVF cells through co-cultivation. Our findings suggest that the positive effects of SVF implantation into impaired bone may be attributed to the rapid induction of MSC osteogenesis, and the transplantation of co-cultured and preconditioned SVF cells and/or MSCs may be more effective than the transplantation of untreated cells for the treatment of bone defects.

Interaction of small G protein signaling modulator 3 with connexin 43 contributes to myocardial infarction in rat hearts.

Connexin 43 (Cx43), a ubiquitous connexin expressed in the heart and skin, is associated with a variety of hereditary conditions. Therefore, the characterization of Cx43-interacting proteins and their dynamics is important to understand not only the molecular mechanisms underlying pathological malfunction of gap junction-mediated intercellular communication but also to identify novel and unanticipated biological functions of Cx43. In the present study, we observed potential targets of Cx43 to determine new molecular functions in cardio-protection. MALDI-TOF mass spectrometry analysis of Cx43 co-immunoprecipitated proteins showed that Cx43 interacts with several proteins related to metabolism. In GeneMANIA network analysis, SGSM3, which has not been previously associated with Cx43, was highly correlated with Cx43 in heart functions, and high levels of SGSM3 appeared to induce the turnover of Cx43 through lysosomal degradation in myocardial infarcted rat hearts. Moreover, we confirmed that lysosomal degradation of Cx43 is dependent upon the interaction between SGSM3 and Cx43 in H9c2 cardiomyocytes. The functional importance of the interaction between SGSM3 and Cx43 was confirmed by results showing that Cx43 expression was enhanced by SGSM3 siRNA knockdown in H9c2 cells. In summary, the results of this study elucidate the molecular mechanisms in which Cx43 with SGSM3 is degraded in myocardial infarcted rat hearts, which may contribute to the establishment of new therapeutic targets to modulate cardiac function in physiological and pathological conditions.

MicroRNA-Mediated Down-Regulation of Apoptosis Signal-Regulating Kinase 1 (ASK1) Attenuates the Apoptosis of Human Mesenchymal Stem Cells (MSCs) Transplanted into Infarcted Heart.

Stem cell therapy using adult stem cells, such as mesenchymal stem cells (MSCs) has produced some promising results in treating the damaged heart. However, the low survival rate of MSCs after transplantation is still one of the crucial factors that limit the therapeutic effect of stem cells. In the damaged heart, oxidative stress due to reactive oxygen species (ROS) production can cause the death of transplanted MSCs. Apoptosis signal-regulating kinase 1 (ASK1) has been implicated in the development of oxidative stress-related pathologic conditions. Thus, we hypothesized that down-regulation of ASK1 in human MSCs (hMSCs) might attenuate the post-transplantation death of MSCs. To test this hypothesis, we screened microRNAs (miRNAs) based on a miRNA-target prediction database and empirical data and investigated the anti-apoptotic effect of selected miRNAs on human adipose-derived stem cells (hASCs) and on rat myocardial infarction (MI) models. Our data indicated that miRNA-301a most significantly suppressed ASK1 expression in hASCs. Apoptosis-related genes were significantly down-regulated in miRNA-301a-enriched hASCs exposed to hypoxic conditions. Taken together, these data show that miRNA-mediated down-regulation of ASK1 protects MSCs during post-transplantation, leading to an increase in the efficacy of MSC-based cell therapy.

Larval chigger mites collected from small mammals in 3 provinces, Korea.

A total of 9,281 larval chigger mites were collected from small mammals captured at Hwaseong-gun, Gyeonggi-do (Province) (2,754 mites from 30 small mammals), Asan city, Chungcheongnam-do (3,358 mites from 48 mammals), and Jangseong-gun, Jeollanam-do (3,169 for 62 mammals) from April-November 2009 in the Republic of Korea (= Korea) and were identified to species. Leptotrombidium pallidum was the predominant species in Hwaseong (95.8%) and Asan (61.2%), while Leptotrombidium scutellare was the predominant species collected from Jangseong (80.1%). Overall, larval chigger mite indices decreased from April (27.3) to June (4.9), then increased in September (95.2) and to a high level in November (169.3). These data suggest that L. pallidum and L. scutellare are the primary vectors of scrub typhus throughout their range in Korea. While other species of larval chigger mites were also collected with some implications in the transmission of Orientia tsutsugamushi, they only accounted for 11.2% of all larval chigger mites collected from small mammals.

Association Between Dietary Fiber Intake and Low Muscle Strength Among Korean Adults.

The health benefits of dietary fiber are widely recognized, but its impact on muscle health remains unclear. Therefore, this study aimed to elucidate the relationship between dietary fiber intake and muscle strength through a cross-sectional analysis of data from the Korea National Health and Examination Survey (KNHANES). Data from a single 24-h dietary recall and handgrip strength tests of 10,883 younger adults aged 19 to 64 years and 3,961 older adults aged ≥ 65 years were analyzed. Low muscle strength was defined as handgrip strength < 28 kg for men and < 18 kg for women. Multivariable linear and logistic regression analyses were conducted to determine the association of dietary fiber intake with muscle strength. Approximately 43% of Korean adults met the recommended intake of dietary fiber, and those with higher dietary fiber consumption also had higher total energy and protein intake. After adjusting for confounding variables, dietary fiber intake was found to be positively associated with maximal handgrip strength in younger women aged 19 to 64 years (ß = 0.015; standard error [SE] = 0.006) and older men aged ≥ 65 years (ß = 0.035; SE = 0.014). For older women aged ≥ 65 years, those in the lowest quartile of dietary fiber intake had a higher risk of low muscle strength than those in the highest quartile after adjustment of confounders (odds ratio 1.709; 95% confidence interval 1.130-2.585). These results suggest that adequate dietary fiber intake may reduce the risk of sarcopenia in older Korean women.

Low dietary vitamin C intake is associated with low muscle strength among elderly Korean women.

Although vitamin C is one of the most important antioxidants, its effect on muscle quality is not fully understood. Therefore, we hypothesized that low dietary vitamin C intake is associated with low muscle strength. To test the hypothesis, a single 24-h dietary recall and handgrip strength test of 10,883 younger adults 19-64 y and 3,961 older adults ≥65 y from the seventh Korea National Health and Examination Survey (KNHANES VII 2016-2018) was analyzed by multivariable linear and logistic regression models, and low muscle strength was defined as handgrip strength <28 kg for men and <18 kg for women. Approximately 15.5% of Korean adults met the recommended intake of dietary vitamin C, and those with higher dietary vitamin C intake had higher total energy and protein intake. After adjusting for confounding variables, including age, body mass index, total energy intake, household income, alcohol consumption, smoking, resistance exercise, medical condition, and dietary intake of protein, vitamin E, and ß-carotene, dietary vitamin C was correlated with maximal handgrip strength in younger women 19-64 y (ß = 0.002; SE = 0.001; P-value = .026) and older women ≥65 y (ß = 0.005; SE = 0.002; P-value = .013). Among older women ≥65 y, those in the lowest quartile of dietary vitamin C intake had a higher risk of low muscle strength compared to those in the highest quartile after adjustment of confounding factors (odds ratio, 2.16; 95% confidence interval, 1.49-3.15). These results imply that adequate dietary vitamin C intake may reduce the risk of sarcopenia in older Korean women.

Role of Lymphatic Embolization in Chylothorax Associated with Gorham-Stout Disease: A Case Report.

A 45-year-old male patient with spontaneous chylothorax and osteolysis in the right 1st and 2nd ribs was diagnosed with Gorham-Stout disease based on clinical manifestations and bone biopsy. The chylothorax temporarily decreased after a successful selective lymphatic embolization. The patient presented with recurrent chylothorax, mild chest discomfort, and progressive osteolysis (despite administering sirolimus) during the follow-up period of 15 months.

Spotted fever group rickettsia closely related to Rickettsia monacensis isolated from ticks in South Jeolla province, Korea.

Rickettsia monacensis, a spotted fever group rickettsia, was isolated from Ixodes nipponensis ticks collected from live-captured small mammals in South Jeolla province, Korea in 2006. Homogenates of tick tissues were inoculated into L929 and Vero cell monolayers using shell vial assays. After several passages, Giemsa staining revealed rickettsia-like organisms in the inoculated Vero cells, but not the L929 cells. Sequencing analysis revealed that the ompA-small part (25-614 bp region), ompA-large part (2849-4455 bp region), nearly full-length ompB (58-4889 bp region) and gltA (196-1236 bp region) of the isolates had similarities of 100%, 99.8%, 99.3% and 99.5%, respectively, to those of R. monacensis. Furthermore, phylogenetic analysis showed that the isolate was grouped into the cluster in the same way as R. monacensis in the trees of all genes examined. These results strongly suggest that the isolate is closely related to R. monacensis. As far as is known, this is the first report of isolation of R. monacensis from ticks in Korea.

Detection of Rickettsia monacensis from Ixodes nipponensis collected from rodents in Gyeonggi and Gangwon Provinces, Republic of Korea.

A total of 1,305 ticks were collected from wild rodents captured monthly, except July and August, during 2008 at three US-ROK operated military training sites and three US military installations in Gyeonggi and Gangwon Provinces, the Republic of Korea (ROK). Ixodes nipponensis was the most frequently collected tick (n = 1,299, 99.5 %), followed by Ixodes pomerantzevi (n = 6, 0.5 %). The ticks were pooled (1-15/sample) and tested by nested polymerase chain reaction (nPCR) for spotted fever group (SFG) rickettsiae with primer sets targeting the outer membrane protein B (ompB), citrate synthase (gltA), and 17-kDa antigen gene loci. A total of 115/197 (58.4 %) pools were positive by nPCR for the outer membrane protein ompB. Nucleotide sequence analysis of 105/115 (91.3 %) ompB targeted nPCR positive products showed a high degree of similarity to Rickettsia monacensis (99.3-100 %, n = 87) and R. japonica (99.5-100 %, n = 18). From the 87 positive samples demonstrating a high degree of similarity to R. monacensis, 15 were selected and analyzed by nPCR for gltA and the 17-kDa genes. A total of 12/15 pooled samples were positive for by nPCR for gltA, with amplicons demonstrating a high degree of similarity to R. monacensis (99.3-99.7 %). A total of 13/15 pooled samples were positive by nPCR for the 17-kDa gene, with amplicons demonstrating a high degree of similarity to R. monacensis (99.4-100 %). These findings demonstrate that R. monacensis is distributed throughout Gyeonggi and Gangwon Provinces in the ROK. Furthermore, data suggest a relative high prevalence of R. monacensis in the tick, I. nipponensis.